Color flow, PW, and CW Doppler are used to evaluate flow patterns of the outflow cannula (Fig. 5). To measure flow velocity in the outflow graft, the PW sample volume should be 1 cm proximal to the aortic anastomosis. The peak velocity in the outflow graft in axial flow pumps usually ranges from 1.0 to 2.0 m/s, with unidirectional and slightly pulsatile flow (Fig. 5D) (105), and it is about 2.1 m/s in a normally functioning pulsatile LVAD (7). Outflow valve regurgitation is defined as retrograde flow seen within the outflow graft occurring during LVAD diastole.
Simulation studies showed that flow patterns of the aortic outflow cannula are significantly affected by the angle of insertion of the LVAD outflow cannula into the native aorta (106). Zones of flow recirculation and high shear stress on the aortic wall can be observed when the cannula is at a 90° angle with the ascending aorta, gradually decreasing in size with decreasing angle. Connecting the LVAD outflow conduit at a shallower angle to the proximal aorta produces fewer secondary flows. However, this inhibits the washing of the aortic valve, which helps to reduce thrombus formation in the proximal aorta.
Inflow cannula obstruction is defined as interrupted flow at the mouth of the inflow cannula occurring during LVAD or RVAD diastole (7). It can be caused by hypovolemia (107), intracardiac clot or thrombus (105,108) (Fig. 6A), misalignment or compression of the interventricular septum (7), and, in RVADs, by the anterior leaflet of the TV, the tricuspid subvalvular apparatus, or an aneurysmal interatrial septum (109,110). Diagnosis can be performed using TTE, TEE, or epicardial echocardiography. Intermittent inflow cannula obstruction was reported in 2 of a 32-patient series studied with a protocol based on TTE (7). The true incidence of cannula obstruction is likely more frequent considering its causative factors, and may well be unrecognized and under-reported. The presence of turbulent flow in color Doppler images is a criterion for an obstructed cannula. PW and CW Doppler can be used for further quantification by measuring velocities in the inflow cannula (Fig. 6B). Intermittent interruptions of the usually continuous laminar diastolic flow into the inflow cannula (7) or a peak velocity greater than 2.3 m/s (6) can be used as indicative of inflow cannula obstruction.
Outflow graft distortion results in acceleration of Doppler velocities proximal in the graft compared with the values measured more distally (7,111). Color Doppler is characterized by a turbulent high-velocity flow at the cannula orifice with a clear flow convergence area. Cannula obstruction can be caused by cannula orifice obstruction (105) or intrinsic obstructing lesions (112). Patient position can worsen graft distortion and the produced obstruction. These result in increased CW and PW velocities at the site of obstruction (7). Complete cannula obstruction will cause the loss of Doppler flow signal in any echocardiographic view (105).
Cannula perforation is an unusual event. One inflow cannula perforation and one outflow cannula perforation were reported in a series of 68 LVAD patients (97). In our series, there is one inflow cannula perforation in 95 patients. Perforation can be suspected if air bubbles are observed in the outflow cannula or aorta using two-dimension echocardiography. If the perforation occurs intraoperatively, air bubbles will persist in the perforated cannula even after thorough deairing and separation from CPB.
Inflow valve regurgitation is the most common cause of LVAD dysfunction in long-term LVAD support (7,113). The incidence of inflow valve dysfunction after 1-yr implantation of a HeartMate LVAD has been reported to be 2.4%–5.3% (112,114) and 2% for the Thoratec/TCI HeartMate and the Thoratec paracorporeal VAD devices (96). Inflow valve incompetence in LVADs that use tissue valves can be due to a torn cusp, dehisced commissures or endocarditis (7,111,115). Hypertension and outflow graft twisting increase afterload to the LVAD and may lead to high pump chamber pressure and inflow valve regurgitation (115).
The normal PW Doppler flow into the apical cannula during LVAD filling is unidirectional and laminar (6) (Fig. 5B). Inflow valve regurgitation is indicated by the presence of biphasic inlet conduit flow pattern in color Doppler images and turbulent flow at the inflow cannula during LVAD ejection (7). PW Doppler shows flow reversal in the inflow cannula during device ejection (6). In patients with inflow valve regurgitation, TEE may demonstrate a nondecompressed or dilated LV, frequent opening of the aortic valve, and reduction of the outflow graft velocity time integral and peak velocities (6,7). Regurgitant flow can be estimated from the product of the graft area by the regurgitant flow velocity–time integral.
A mismatch between Doppler-derived cardiac output at the pulmonic valve and device output, i.e., between LVAD output and forward cardiac output, will be observed in the case of inflow valve regurgitation. Such mismatch can also be found in other conditions, such as during outflow valve regurgitation, native or prosthetic valve regurgitation, and incomplete filling of the VAD chamber. Consequently, the finding of that mismatch should always alert to the presence of device malfunction (116) or of a potentially serious condition.
Outflow valve regurgitation has been reported in 3% of patients receiving LVADs within 547 days after insertion (97). The presence of retrograde flow within the outflow graft during LVAD diastole in color Doppler images is indicative of outflow valve regurgitation (7,40). This finding will be associated with a mismatch between the high LVAD output and the effective forward cardiac output due to the increased number of LVAD beats caused by the regurgitation.
Thrombotic complications can occur in these pumps, and protocols for fast evaluation of axial pump LVADs have been developed (105). Because of the devices’ echogenicity, it is not possible to visualize thrombi within the pump. Thromboembolic material can develop and be detected in the LA appendage or the LV apex and impair forward flow. Thrombi have been also found in the small pocket next to the LVAD inflow cannula orifice and interventricular septum-inferior wall, frequently associated with low regional flow assessed by PW Doppler (105). It is also essential to exclude, with TEE, the presence of obstruction of the inflow and outflow cannula and other sources of thromboemboli (Fig. 6).
A variety of new devices with alternative principles and cannulation methods have been introduced. Besides the general considerations after VAD placement, as discussed above, such as LV unloading, RV function, deairing, and PFO detection, they also require specific echocardiographic considerations (Table 2). We will describe three devices to exemplify some of the alternative methods.
The incidence of excessive bleeding after LVAD insertion has been reported with high variability, ranging from 11% to 48%, (99,119–121) and 0.6 non-neurological bleeding events/patient/year in the REMATCH experience (97). This variability is due to factors such as device characteristics, surgical and anesthetic management, and definition of bleeding. More recently, it seems that the incidence of bleeding is decreasing, a fact that can be assigned to improved experience with devices and perioperative patient management, use of antifibrinolytics, and advances in surgical techniques. Two-dimensional TEE for assessment of bleeding after implantation of a device allows for determination of the site and estimation of the volume of pericardial effusion (122), hemopericardium, and distortion, partial displacement and compression of one or more cardiac chambers, despite the limitations of echocardiography for diagnosis of tamponade (123,124). Cardiac tamponade is one of the most common reasons for hemodynamic instability after VAD insertion. Findings compatible with tamponade are RA systolic collapse, RV diastolic collapse, reciprocal respiratory changes in RV and LV volume, swinging heart and IVC plethora (reduction in dilated IVC diameter ≤50% during inspiration), and respiratory flow variation of mitral and tricuspid inflow velocities (123,124). Regional tamponade may be associated with LA compression and LV diastolic compression without collapse of the RA or RV (123). Isolated tamponade due to anterior mediastinal clot can be somewhat difficult to visualize echocardiographically. Tamponade should be suspected when a decline in cardiac output is observed in a small or nondistended ventricle on reduced or partial mechanical support (125).
The presence of intracavitary thrombi requires extra care during cannulation because of the risk of embolism (126). The incidence of thromboembolic complications after LVAD support varies significantly in different reports from 5% to 47% (98,99,127,128). This wide range reflects the variability in device thrombogenicity, patient characteristics and anticoagulation management principles in different studies. LV thrombus has been reported to occur in 9% and 16% of patients receiving VADs (6,126). LA cannulation was found to be an independent risk factor for LVAD-associated LV thrombus (126). In this study, 7 of 13 patients with LA cannulation presented LV thrombus in contrast to 1 of 44 for LV cannulation. The two-dimensional TEE examination for assessment of emboli or thrombus after implantation of a device will include all cardiac chambers, particularly the LA, LA appendage, and apex of the LV, which is the insertion site of the inflow cannula. Use of TEE allows for identification of mobile LV thrombi adjacent to the LVAD inflow cannula (129) (Fig. 6), and the LV outflow tract (41).
Infection is an important cause of morbidity and mortality after LVAD implantation (127,133,134). VAD endocarditis is established when the inner components of the VAD are infected (135). This will often be associated with mechanical complications of the VAD (127). TEE is recommended to evaluate endocarditis (136). Echocardiographic findings suggestive of VAD endocarditis are: 1) visualization of echodense structures compatible with vegetations on the inflow or outflow conduits, as well as in native or prosthetic valves (136,137); 2) LVAD inlet obstruction (127); 3) Inflow and outflow valve malfunction (138); 4) LVAD outflow rupture (127).
Echocardiography is very useful for detection and management of micro- or macro-bubbles, observed in the echocardiographic image as white reflections (139–141). The VAD and its cannulas may harbor a significant amount of air. This adds to the general common sites of intracardiac air after open-heart surgery such as the right and left upper pulmonary veins, LV apex, LA, right coronary sinus of Valsalva, LA appendage, and PA (140,141). Reestablishment of pulmonary perfusion after CPB will result in the transport of the air bubbles to the heart and systemic circulation. The most common locations to which air will migrate are the right coronary artery and the innominate artery (142). This may produce right coronary ischemia and RV dysfunction or contribute to postoperative neurocognitive impairment.
Three distinct perioperative periods are relevant to air detection: from the conclusion of device anastomoses to release of the aortic cross-clamp, from release of the aortic cross-clamp to termination of CPB, and from the end of CPB to the end of operation (141). The first two periods are the most critical, because they will correspond to the removal of the largest amount of intravascular and intracavitary air and, consequently, reduce the likelihood of subsequent complications.
Careful deairing is performed before the device is fully activated. To observe signs of air entrapment in the device, structures distal to the outflow cannula should be inspected. These include the ascending and descending aorta using the ME aortic valve long-axis view, ME ascending aorta long-axis view and descending aorta short- and long-axis view. The ME aortic valve long-axis view will allow for observation of both air from the outflow cannula and air present in ventral regions of the heart chambers, where bubbles would most likely collect. Finally, anastomotic sites, such as at the ascending aorta, descending aorta, pulmonary trunk, RA or LV apex, can be a source of air entrance. This is particularly important in the case of an air entry port in the circuit upstream to the device (i.e., inflow cannula and respective anastomosis), due to the negative pressures generated by several devices during filling (e.g., ABIOMED AB5000, Thoratec, HeartMate I). Air entrapment due to this mechanism can also occur postoperatively and result in air embolism with RV failure and neurological complications (142,143).
LV and RV recovery can occur after VAD implantation. Several studies have reported recovery and weaning strategies based on cardiopulmonary testing, and hemodynamic and echocardiographic variables (144–146). Echocardiographic variables indicative of left myocardial recovery are LVEF >45% (147), LV internal diameter in diastole (LVIDd) <45 mm (142), fractional area change >40% (148), and improved myocardial ventricular contractility (2). The largest series of weaning and removal from chronic LVAD support used a LVEF ≥40% and LVIDd <60 mm as echocardiographic criteria for myocardial recovery (93). Dobutamine stress echocardiography, combined with invasive hemodynamic monitoring, has been proposed to assess the ability of LV response to the increased load and to consider device explantation (149). This test is performed with an infusion at 5 μg · kg−1 · min−1 titrated every 5 min up to 40 μg · kg−1 · min−1 and simultaneous assessment of cardiac index, LVEF, LVIDd, and dP/dt. The test is halted if the patient demonstrates symptoms of heart failure or unacceptable hemodynamics. The favorable test is defined as the improvement of cardiac index and LVEF without symptoms of heart failure, and pulmonary capillary wedge pressure ≤15 mm Hg.
Less quantitative data are available for weaning from a RVAD. The PVR is a crucial variable in this case, and most patients can be weaned once the PVR is optimized (150). Patients with malignant arrhythmias or fixed PVR will need additional management to allow for weaning. During the weaning process, the RVAD flows are decreased, e.g., by setting a pulsatile RVAD to the asynchronous mode and progressively reducing the pumping rate and vacuum (151). The central venous pressure, PVR, RV, and LV function are assessed throughout the process (150). If the left and right components of the circulation continue to fill and function without excessive elevation of the central venous pressure, the RVAD can be further weaned and ultimately removed.
It is important to recognize that identification of the patient ready for successful LVAD and RVAD weaning is still a topic of current study and depends on integration of clinical and echocardiographic factors (98,152).
LVAD implantation has been increasingly used in patients with terminal heart failure as a bridge to transplant or recovery, and as destination therapy. Echocardiography plays a fundamental role in evaluating perioperative structure and function related both to the patient’s heart and large vessels and to the implanted device. This evaluation is essential for anesthetic and surgical planning and intervention success. A comprehensive echocardiographic examination includes a pre- and a post-VAD assessment phases. The pre-VAD insertion examination of the heart and large vessels addresses the structural and functional factors relevant to anesthetic and surgical management: aortic regurgitation, tricuspid regurgitation, mitral stenosis, patent foramen ovale or other cardiac abnormalities that could lead to right-to-left shunt after LVAD placement, intracardiac thrombi, ventricular scars, pulmonic regurgitation, pulmonary hypertension, pulmonary embolism, and atherosclerotic disease in the ascending aorta, and RV function. The post-VAD insertion examination addresses device function and reassessment of the heart and large vessels. The examination of the device aims to confirm completeness of device and heart deairing, cannula alignment and patency, and competency of device valves using two-dimensional, and color, CW, and PW Doppler modalities. The examination of the heart targets to exclude aortic regurgitation, or an uncovered right-to-left shunt; and to assess RV function, LV unloading, and the effect of device settings on global heart function. Specific echocardiographic considerations should be taken into account according to the VAD model used. Performance of an echocardiographic assessment firmly based on the principles detailed in this review can optimize perioperative clinical management and provide data for objective decision-making in patients receiving VADs.
The authors would like to thank the members of the Cardiac Anesthesia Group who contributed with the acquisition of the images: Drs. Edwin Avery, Michael D’Ambra, Dwight Geha, Fumito Ichinose, Carolyn Mehaffey, Vipin Mehta, Robert Schneider, Scott Streckenbach, Jason Qu, and Xiping Zhang; Mark Handschumacher for the preparation of images for the website supplement; Mark S. Adams, BS, RDCS, FASE, for his helpful suggestions on the manuscript; and O.H. Frazier, MD, and C. J. Genmato, BS, for the web supplement images on the Jarvik 2000 and TandemHeart.
1. Hetzer R, Muller JH, Weng YG, Loebe M, Wallukat G. Midterm follow-up of patients who underwent removal of a left ventricular assist device after cardiac recovery from end-stage dilated cardiomyopathy. J Thorac Cardiovasc Surg 2000;120:843–53
2. Leprince P, Combes A, Bonnet N, Ouattara A, Luyt CE, Theodore P, Leger P, Pavie A. Circulatory support for fulminant myocarditis: consideration for implantation, weaning and explantation. Eur J Cardiothorac Surg 2003;24:399–403
3. Kirklin JK, Holman WL. Mechanical circulatory support therapy as a bridge to transplant or recovery (new advances). Curr Opin Cardiol 2006;21:120–6
4. Park SJ, Tector A, Piccioni W, Raines E, Gelijns A, Moskowitz A, Rose E, Holman W, Furukawa S, Frazier OH, Dembitsky W. Left ventricular assist devices as destination therapy: a new look at survival. J Thorac Cardiovasc Surg 2005;129:9–17
5. Rose EA, Gelijns AC, Moskowitz AJ, Heitjan DF, Stevenson LW, Dembitsky W, Long JW, Ascheim DD, Tierney AR, Levitan RG, Watson JT, Meier P, Ronan NS, Shapiro PA, Lazar RM, Miller LW, Gupta L, Frazier OH, Desvigne-Nickens P, Oz MC, Poirier VL; Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) Study Group. Long-term mechanical left ventricular assistance for end-stage heart failure. N Engl J Med 2001;345:1435–43
6. Scalia GM, McCarthy PM, Savage RM, Smedira NG, Thomas JD. Clinical utility of echocardiography in the management of implantable ventricular assist devices. J Am Soc Echocardiogr 2000;13:754–63
7. Horton SC, Khodaverdian R, Chatelain P, McIntosh ML, Horne BD, Muhlestein JB, Long JW. Left ventricular assist device malfunction: an approach to diagnosis by echocardiography. J Am Coll Cardiol 2005;45:1435–40
8. Frazier OH, Myers TJ, Jarvik RK, Westaby S, Pigott DW, Gregoric ID, Khan T, Tamez DW, Conger JL, Macris MP. Research and development of an implantable, axial-flow left ventricular assist device: the Jarvik 2000 Heart. Ann Thorac Surg 2001;71:S125–32
9. Tittle SL, Mandapati D, Kopf GS, Elefteriades JA. Alternate technique for implantation of left ventricular assist system: left thoracotomy for reoperative cases. Ann Thorac Surg 2002;73: 994–6
10. Mihaylov D, Verkerke GJ, Rakhorst G. Mechanical circulatory support systems—a review. Technol Health Care 2000;8:251–66
11. Gemmato CJ, Forrester MD, Myers TJ, Frazier OH, Cooley DA. Thirty-five years of mechanical circulatory support at the Texas Heart Institute: an updated overview. Tex Heart Inst J 2005;32:168–77
12. Song X, Throckmorton AL, Untaroiu A, Patel S, Allaire PE, Wood HG, Olsen DB. Axial flow blood pumps. ASAIO J 2003;49:355–64
13. Noon GP, Lafuente JA, Irwin S. Acute and temporary ventricular support with BioMedicus centrifugal pump. Ann Thorac Surg 1999;68:650–4
14. Vranckx P, Foley DP, de Feijter PJ, Vos J, Smits P, Serruys PW. Clinical introduction of the Tandemheart, a percutaneous left ventricular assist device, for circulatory support during high-risk percutaneous coronary intervention. Int J Cardiovasc Intervent 2003;5:35–9
15. Stainback RF, Croitoru M, Hernandez A, Myers TJ, Wadia Y, Frazier OH. Echocardiographic evaluation of the Jarvik 2000 axial-flow LVAD. Tex Heart Inst J 2005;32:263–70
16. Maybaum S, Williams M, Barbone A, Levin H, Oz M, Mancini D. Assessment of synchrony relationships between the native left ventricle and the HeartMate left ventricular assist device. J Heart Lung Transplant 2002;21:509–15
17. Practice guidelines for perioperative transesophageal echocardiography. A report by the American Society of Anesthesiologists and the Society of Cardiovascular Anesthesiologists Task Force on transesophageal echocardiography. Anesthesiology 1996;84:986–1006
18. Joffe II, Jacobs LE, Lampert C, Owen AA, Ioli AW, Kotler MN. Role of echocardiography in perioperative management of patients undergoing open heart surgery. Am Heart J 1996;131:162–76
19. Peterson GE, Brickner ME, Reimold SC. Transesophageal echocardiography: clinical indications and applications. Circulation 2003;107:2398–402
20. Shanewise JS, Cheung AT, Aronson S, Stewart WJ, Weiss RL, Mark JB, Savage RM, Sears-Rogan P, Mathew JP, Quinones MA, Cahalan MK, Savino JS. ASE/SCA guidelines for performing a comprehensive intraoperative multiplane transesophageal echocardiography examination: recommendations of the American Society of Echocardiography Council for Intraoperative Echocardiography and the Society of Cardiovascular Anesthesiologists Task Force for certification in perioperative transesophageal echocardiography. J Am Soc Echocardiogr 1999;12:884–900
21. Penco M, Paparoni S, Dagianti A, Fusilli C, Vitarelli A, De Remigis F, Mazzola A, Di Luzio V, Gregorini R, D’Eusanio G. Usefulness of transesophageal echocardiography in the assessment of aortic dissection. Am J Cardiol 2000;86:G53–6
22. Vitarelli A, Gheorghiade M. Transthoracic and transesophageal echocardiography in the hemodynamic assessment of patients with congestive heart failure. Am J Cardiol 2000; 86:36–40
23. Hagen PT, Scholz DG, Edwards WD. Incidence and size of patent foramen ovale during the first 10 decades of life an autopsy study of 965 normal hearts. Mayo Clin Proc 1984;59:17–20
24. de Belder MA, Tourikis L, Griffith M, Leech G, Camm AJ. Transesophageal contrast echocardiography and color flow mapping: methods of choice for the detection of shunts at the atrial level? Am Heart J 1992;124:1545–50
25. Stefanadis C, Dernellis J, Stratos C, Tsiamis E, Tsioufis C, Toutouzas K, Vlachopoulos C, Pitsavos C, Toutouzas P. Assessment of left atrial pressure-area relation in humans by means of retrograde left atrial catheterization and echocardiographic automatic boundary detection: effects of dobutamine. J Am Coll Cardiol 1998;31:426–36
26. Liao KK, Miller L, Toher C, Ormaza S, Herrington CS, Bittner HB, Park SJ. Timing of transesophageal echocardiography in diagnosing patent foramen ovale in patients supported with left ventricular assist device. Ann Thorac Surg 2003;75:1624–6
27. Kyo S, Matsumura M, Takamoto S, Omoto R. Transesophageal color Doppler echocardiography during mechanical assist circulation. ASAIO Trans 1989;35:722–5
28. Shapiro GC, Leibowitz DW, Oz MC, Weslow RG, Di Tullio MR, Homma S. Diagnosis of patent foramen ovale with transesophageal echocardiography in a patient supported with a left ventricular assist device. J Heart Lung Transplant 1995;14:594–7
29. Kilger E, Strom C, Frey L, Felbinger TW, Pichler B, Tichy M, Rank N, Wheeldon D, Kesel K, Schmitz C, Reichenspurner H, Polasek J, Weis F, Goetz AE. Intermittent atrial level right-to-left shunt with temporary hypoxemia in a patient during support with a left ventricular assist device. Acta Anaesthesiol Scand 2000;44:125–7
30. Baker JE, Stratmann G, Hoopes C, Donateillo R, Tseng E, Russell IA. Profound hypoxemia resulting from shunting across an inadvertent atrial septal tear after left ventricular assist device placement. Anesth Analg 2004;98:937–40
31. Peters J, Fraser C, Stuart RS, Baumgartner W, Robotham JL. Negative intrathoracic pressure decreases independently left ventricular filling and emptying. Am J Physiol 1989;257:H120–31
32. Nussmeier NA, Probert CB, Hirsch D, Cooper JR Jr, Gregoric ID, Myers TJ, Frazier OH. Anesthetic management for implantation of the Jarvik 2000 left ventricular assist system. Anesth Analg 2003;97:964–71
33. Rao V, Slater JP, Edwards NM, Naka Y, Oz MC. Surgical management of valvular disease in patients requiring left ventricular assist device support. Ann Thorac Surg 2001; 71:1448–53
34. Bryant AS, Holman WL, Nanda NC, Vengala S, Blood MS, Pamboukian SV, Kirklin JK. Native aortic valve insufficiency in patients with left ventricular assist devices. Ann Thorac Surg 2006;81:E6–8
35. Rahimtoola SH. The year in valvular heart disease. J Am Coll Cardiol 2005;45:111–22
36. Pelletier MP, Chang CP, Vagelos R, Robbins RC. Alternative approach for use of a left ventricular assist device with a thrombosed prosthetic valve. J Heart Lung Transplant 2002; 21:402–4
37. Swartz MT, Lowdermilk GA, Moroney DA, McBride LR. Ventricular assist device support in patients with mechanical heart valves. Ann Thorac Surg 1999;68:2248–51
38. Holman WL, Bourge RC, Fan P, Kirklin JK, Pacifico AD, Nanda NC. Influence of left ventricular assist on valvular regurgitation. Circulation 1993;88:309–18
39. Samuels LE, Thomas MP, Holmes EC, Narula J, Fitzpatrick J, Wood D, Fyfe B, Wechsler AS. Insufficiency of the native aortic valve and left ventricular assist system inflow valve after support with an implantable left ventricular assist system: signs, symptoms, and concerns. J Thorac Cardiovasc Surg 2001;122:380–1
40. Amir O, Kar B, Delgado RM III, Younis AG, Gregoric ID, Smart FW, Radovancevic B, Frazier OH. Images in cardiovascular medicine. High left ventricular assist device flows resulting from combined native aortic valve and outflow valve regurgitation. Circulation 2005;111:E34
41. Gruber EM, Seitelberger R, Mares P, Hiesmayr MJ. Ventricular thrombus and subarachnoid bleeding during support with ventricular assist devices. Ann Thorac Surg 1999;67:1778–80
42. Lacroix V, d’Udekem Y, Jacquet L, Noirhomme P. Resection of the ascending aorta and aortic valve patch closure for type A aortic dissection after Novacor LVAD insertion. Eur J Cardiothorac Surg 2003;24:309–11
43. Momeni M, Van Caenegem O, Van Dyck MJ. Aortic regurgitation after left ventricular assist device placement. J Cardiothorac Vasc Anesth 2005;19:409–10
44. Rose AG, Connelly JH, Park SJ, Frazier OH, Miller LW, Ormaza S. Total left ventricular outflow tract obstruction due to left ventricular assist device-induced sub-aortic thrombosis in 2 patients with aortic valve bioprosthesis. J Heart Lung Transplant 2003;22:594–9
45. Connelly JH, Abrams J, Klima T, Vaughn WK, Frazier OH. Acquired commissural fusion of aortic valves in patients with left ventricular assist devices. J Heart Lung Transplant 2003;22:1291–5
46. Baradarian S, Dembitsky WP, Jaski B, Abolhoda A, Adamson R, Chillcot S, Daily PO. Left ventricular outflow tract obstruction associated with chronic ventricular assist device support. ASAIO J 2002;48:665–7
47. Rose AG, Park SJ, Bank AJ, Miller LW. Partial aortic valve fusion induced by left ventricular assist device. Ann Thorac Surg 2000;70:1270–4
48. Rose AG, Park SJ. Pathology in patients with ventricular assist devices: a study of 21 autopsies, 24 ventricular apical core biopsies and 24 explanted hearts. Cardiovasc Pathol 2005;14: 19–23
49. Katz ES, Tunick PA, Rusinek H, Ribakove G, Spencer FC, Kronzon I. Protruding aortic atheromas predict stroke in elderly patients undergoing cardiopulmonary bypass: experience with intraoperative transesophageal echocardiography. J Am Coll Cardiol 1992;20:70–7
50. Tenenbaum A, Fisman EZ, Schneiderman J, Stroh CI, Shemesh J, Schwammenthal E, Vered Z, Motro M. Disrupted mobile aortic plaques are a major risk factor for systemic embolism in the elderly. Cardiology 1998;89:246–51
51. Vitebskiy S, Fox K, Hoit BD. Routine transesophageal echocardiography for the evaluation of cerebral emboli in elderly patients. Echocardiography 2005;22:770–4
52. Hartman GS, Yao FS, Bruefach M III, Barbut D, Peterson JC, Purcell MH, Charlson ME, Gold JP, Thomas SJ, Szatrowski TP. Severity of aortic atheromatous disease diagnosed by transesophageal echocardiography predicts stroke and other outcomes associated with coronary artery surgery: a prospective study. Anesth Analg 1996;83:701–8
53. Koelling TM, Aaronson KD, Cody RJ, Bach DS, Armstrong WF. Prognostic significance of mitral regurgitation and tricuspid regurgitation in patients with left ventricular systolic dysfunction. Am Heart J 2002;144:524–9
54. Dreyfus GD, Corbi PJ, Chan KM, Bahrami T. Secondary tricuspid regurgitation or dilatation: which should be the criteria for surgical repair?. Ann Thorac Surg 2005;79:127–32
55. Gibson TC, Foale RA, Guyer DE, Weyman AE. Clinical significance of incomplete tricuspid valve closure seen on two-dimensional echocardiography. J Am Coll Cardiol 1984;4:1052–7
56. Mukherjee D, Nader S, Olano A, Garcia MJ, Griffin BP. Improvement in right ventricular systolic function after surgical correction of isolated tricuspid regurgitation. J Am Soc Echocardiogr 2000;13:650–4
57. Chumnanvej S, Wood MJ, MacGillivray TE, Vidal Melo MF. Effect of tricuspid annuloplasty on postoperative tricuspid regurgitation following left ventricular assist device implantation. Anesth Analg 2006;102:SCA54
58. Bursi F, Enriquez-Sarano M, Nkomo VT, Jacobsen SJ, Weston SA, Meverden RA, Roger VL. Heart failure and death after myocardial infarction in the community: the emerging role of mitral regurgitation. Circulation 2005;111:295–301
59. Patel JB, Borgeson DD, Barnes ME, Rihal CS, Daly RC, Redfield MM. Mitral regurgitation in patients with advanced systolic heart failure. J Card Fail 2004;10:285–91
60. Yiu SF, Enriquez-Sarano M, Tribouilloy C, Seward JB, Tajik AJ. Determinants of the degree of functional mitral regurgitation in patients with systolic left ventricular dysfunction: a quantitative clinical study. Circulation 2000;102:1400–6
61. Uemura T, Otsuji Y, Nakashiki K, Yoshifuku S, Maki Y, Yu B, Mizukami N, Kuwahara E, Hamasaki S, Biro S, Kisanuki A, Minagoe S, Levine RA, Tei C. Papillary muscle dysfunction attenuates ischemic mitral regurgitation in patients with localized basal inferior left ventricular remodeling: insights from tissue Doppler strain imaging. J Am Coll Cardiol 2005;46: 113–19
62. Sabbah HN, Rosman H, Kono T, Alam M, Khaja F, Goldstein S. On the mechanism of functional mitral regurgitation. Am J Cardiol 1993;72:1074–6
63. Santamore WP, Gray LA Jr. Left ventricular contributions to right ventricular systolic function during LVAD support. Ann Thorac Surg 1996;61:350–6
64. Farrar DJ, Hill JD, Pennington DG, McBride LR, Holman WL, Kormos RL, Esmore D, Gray LA Jr, Seifert PE, Schoettle GP, Moore CH, Hendry PJ, Bhayana JN. Preoperative and postoperative comparison of patients with univentricular and biventricular support with the thoratec ventricular assist device as a bridge to cardiac transplantation. J Thorac Cardiovasc Surg 1997;113:202–9
65. Kormos RL, Gasior TA, Kawai A, Pham SM, Murali S, Hattler BG, Griffith BP. Transplant candidate’s clinical status rather than right ventricular function defines need for univentricular versus biventricular support. J Thorac Cardiovasc Surg 1996;111:773–82
66. Kaul TK, Fields BL. Postoperative acute refractory right ventricular failure: incidence, pathogenesis, management and prognosis. Cardiovasc Surg 2000;8:1–9
67. Ochiai Y, McCarthy PM, Smedira NG, Banbury MK, Navia JL, Feng J, Hsu AP, Yeager ML, Buda T, Hoercher KJ, Howard MW, Takagaki M, Doi K, Fukamachi K. Predictors of severe right ventricular failure after implantable left ventricular assist device insertion: analysis of 245 patients. Circulation 2002; 106:I198–202
68. Miller LW. Patient selection for the use of ventricular assist devices as a bridge to transplantation. Ann Thorac Surg 2003;75:S66–71
69. Kavarana MN, Pessin-Minsley MS, Urtecho J, Catanese KA, Flannery M, Oz MC, Naka Y. Right ventricular dysfunction and organ failure in left ventricular assist device recipients: a continuing problem. Ann Thorac Surg 2002;73:745–50
70. Morgan JA, John R, Lee BJ, Oz MC, Naka Y. Is severe right ventricular failure in left ventricular assist device recipients a risk factor for unsuccessful bridging to transplant and post-transplant mortality. Ann Thorac Surg 2004;77:859–63
71. Morita S, Kormos RL, Mandarino WA, Eishi K, Kawai A, Gasior TA, Deneault LG, Armitage JM, Hardesty RL, Griffith BP. Right ventricular/arterial coupling in the patient with left ventricular assistance. Circulation 1992;86:II316–25
72. Schmid C, Radovancevic B. When should we consider right ventricular support? Thorac Cardiovasc Surg 2002;50:204–7
73. Kawai A, Kormos RL, Mandarino WA, Morita S, Deneault LG, Gasior TA, Armitage JM, Griffith BP. Differential regional function of the right ventricle during the use of a left ventricular assist device. ASAIO J 1992;38:M676–8
74. Mendes LA, Picard MH, Sleeper LA, Thompson CR, Jacobs AK, White HD, Hochman JS, Davidoff R. Cardiogenic shock: predictors of outcome based on right and left ventricular size and function at presentation. Coron Artery Dis 2005;16:209–15
75. Maslow AD, Regan MM, Panzica P, Heindel S, Mashikian J, Comunale ME. Precardiopulmonary bypass right ventricular function is associated with poor outcome after coronary artery bypass grafting in patients with severe left ventricular systolic dysfunction. Anesth Analg 2002;95:1507–18
76. Vaur L, Abergel E, Laaban JP, Raffoul H, Jeanrenaud X, Diebold B. Quantitative analysis of systolic function of the right ventricule by Doppler echocardiography. Arch Mal Coeur Vaiss 1991;84:89–93
77. Yamada S, Nakatani S, Imanishi T, Nakasone I, Sunagawa K, Miyatake K. Estimation of right ventricular contractility by continuous-wave Doppler echocardiography. J Cardiol 1996; 28:287–93
78. Moon MR, DeAnda A, Castro LJ, Daughters GT III, Ingels NB Jr, Miller DC. Effects of mechanical left ventricular support on right ventricular diastolic function. J Heart Lung Transplant 1997;16:398–407
79. Fukamachi K, McCarthy PM, Smedira NG, Vargo RL, Starling RC, Young JB. Preoperative risk factors for right ventricular failure after implantable left ventricular assist device insertion. Ann Thorac Surg 1999;68:2181–4
80. Nakatani S, Thomas JD, Savage RM, Vargo RL, Smedira NG, McCarthy PM. Prediction of right ventricular dysfunction after left ventricular assist device implantation. Circulation 1996; 94:II216–21
81. Moazami N, Pasque MK, Moon MR, Herren RL, Bailey MS, Lawton JS, Damiano RJ Jr. Mechanical support for isolated right ventricular failure in patients after cardiotomy. J Heart Lung Transplant 2004;23:1371–5
82. Lip GYH, Gibbs CR, Beevers DG. ABC of heart failure: aetiology. BMJ 2000;320:104–7
83. Gracin N, Johnson MR, Spokas D, Allen J, Bartlett L, Piccione W, Parrillo JE, Costanzo MR, Calvin JE. The use of APACHE II scores to select candidates for left ventricular assist device placement. Acute Physiology and Chronic Health Evaluation. J Heart Lung Transplant 1998;17:1017–23
84. Badano LP, Albanese MC, De Biaggio P, Rozbowsky P, Miani D, Fresco C, Fioretti PM. Prevalence, clinical characteristics, quality of life, and prognosis of patients with congestive heart failure and isolated left ventricular diastolic dysfunction. J Am Soc Echocardiogr 2004;17:253–61
85. Khouri SJ, Maly GT, Suh DD, Walsh TE. A practical approach to the echocardiographic evaluation of diastolic function. J Am Soc Echocardiogr 2004;17:290–7
86. Nagueh SF, Middleton KJ, Kopelen HA, Zoghbi WA, Quiñones MA. Doppler tissue imaging: a noninvasive technique for evaluation of left ventricular relaxation and estimation of filling pressures. J Am Coll Cardiol 1997;30:1527–33
87. Richartz BM, Werner GS, Ferrari M, Figulla HR. Comparison of left ventricular systolic and diastolic function in patients with idiopathic dilated cardiomyopathy and mild heart failure versus those with severe heart failure. Am J Cardiol 2002; 90:390–4
88. Wood MJ, Picard MH. Utility of echocardiography in the evaluation of individuals with cardiomyopathy. Heart 2004;90:707–12
89. Pinamonti B, Zecchin M, Di Lenarda A, Gregori D, Sinagra G, Camerini F. Persistence of restrictive left ventricular filling pattern in dilated cardiomyopathy: an ominous prognostic sign. J Am Coll Cardiol 1997;29:604–12
90. Hamilton A, Huang SL, Warnick D, Stein A, Rabbat M, Madhav T, Kane B, Nagaraj A, Klegerman M, MacDonald R, McPherson D. Left ventricular thrombus enhancement after intravenous injection of echogenic immunoliposomes: studies in a new experimental model. Circulation 2002;105:2772–8
91. Ishino K, Murakami T, Takata K, Kino K, Senoo Y, Teramoto S. Assessment of myocardial function during mechanical left ventricular support using serial echocardiography: a case report. Acta Med Okayama 1994;48:165–8
92. Dalby MC, Banner NR, Tansley P, Grieve LA, Partridge J, Yacoub MH. Left ventricular function during support with an asynchronous pulsatile left ventricular assist device. J Heart Lung Transplant 2003;22:292–300
93. Hetzer R, Muller JH, Weng Y, Meyer R, Dandel M. Bridging-to-recovery. Ann Thorac Surg 2001;71:S109–13; discussion S114–15
94. Nakatani T, Takano H, Beppu S, Noda H, Taenaka Y, Kumon K, Kito Y, Fujita T, Kawashima Y. Practical assessment of natural heart function using echocardiography in mechanically assisted patients. ASAIO Trans 1991;37:M420–1
95. Mandarino WA, Gorcsan J III, Gasior TA, Pham S, Griffith BP, Kormos RL. Estimation of left ventricular function in patients with a left ventricular assist device. ASAIO J 1995;41:M544–7
96. Birks EJ, Tansley PD, Yacoub MH, Bowles CT, Hipkin M, Hardy J, Banner NR, Khaghani A. Incidence and clinical management of life-threatening left ventricular assist device failure. J Heart Lung Transplant 2004;23:964–9
97. Dembitsky WP, Tector AJ, Park S, Moskowitz AJ, Gelijns AC, Ronan NS, Piccione W Jr, Holman WL, Furukawa S, Weinberg AD, Heatley G, Poirier VL, Damme L, Long JW. Left ventricular assist device performance with long-term circulatory support: lessons from the REMATCH trial. Ann Thorac Surg 2004;78:2123–9
98. Sun BC, Catanese KA, Spanier TB, Flannery MR, Gardocki MT, Marcus LS, Levin HR, Rose EA, Oz MC. 100 long-term implantable left ventricular assist devices: the Columbia Presbyterian interim experience. Ann Thorac Surg 1999;68:688–94
99. Frazier OH, Rose EA, Oz MC, Dembitsky W, McCarthy P, Radovancevic B, Poirier VL, Dasse KA; HeartMate LVAS Investigators. Multicenter clinical evaluation of the HeartMate vented electric left ventricular assist system in patients awaiting heart transplantation. J Thorac Cardiovasc Surg 2001; 122:1186–95
100. Ferns J, Dowling R, Bhat G. Evaluation of a patient with left ventricular assist device dysfunction. ASAIO J 2001;47:696–8
101. Kormos RL, Griffith BP. Ventricular assist. In: Kaiser LR, Kron IL, Spray TL, eds. Mastery of cardiothoracic surgery. 1st ed. Philadelphia: Lippincott-Raven, 1998:521–7
102. Westaby S, Frazier OH, Pigott DW, Saito S, Jarvik RK. Implant technique for the Jarvik 2000 Heart. Ann Thorac Surg 2002;73:1337–40
103. Minami K, Bonkohara Y, Arusoglu L, El-Banayosy A, Korfer R. New technique for the outflow cannulation of right ventricular assist device. Ann Thorac Surg 1999;68:1092–3
104. Petrofski JA, Patel VS, Russell SD, Milano CA. BVS5000 support after cardiac transplantation. J Thorac Cardiovasc Surg 2003;126:442–7
105. Catena E, Milazzo F, Montorsi E, Bruschi G, Cannata A, Russo C, Barosi A, Tarelli G, Tartara P, Paino R, Vitali E. Left ventricular support by axial flow pump: the echocardiographic approach to device malfunction. J Am Soc Echocardiogr 2005;18:1422
106. May-Newman KD, Hillen BK, Sironda CS, Dembitsky W. Effect of LVAD outflow conduit insertion angle on flow through the native aorta. J Med Engl Technol 2004;28:105–9
107. Noon GP, Morley DL, Irwin S, Abdelsayed SV, Benkowski RJ, Lynch BE. Clinical experience with the MicroMed DeBakey ventricular assist device. Ann Thorac Surg 2001;71:S133–8
108. Kececioglu D, Galal O, Halees Z, Fadely F, Wilson N, Vogt J. Transesophageal echocardiography in children with cardiac assist. Thorac Cardiovasc Surg 1994;42:21–4
109. Kaplon RJ, Qi XS, Andreopoulos FM, Anderson MB, Bauerlein E, Nejman A, Pham SM. Tricuspid valvectomy for right ventricular outflow cannula occlusion with the Thoratec ventricular assist device. J Thorac Cardiovasc Surg 2001;121:812–13
110. Augoustides J, Mancini DJ, Horak J, Pochettino A, Dupont F, Dowling RD. CASE 1–2003. The use of intraoperative echocardiography during insertion of ventricular assist devices. J Cardiothorac Vasc Anesth 2003;17:113–20
111. Croitoru M, Stainback R, Frazier OH, Radovancevic B, Myers T, Miller K, Hernandez A, Wilansky S. Echocardiography for early detection of left ventricular assist system inlet and outlet conduit dysfunction. J Congestive Heart Fail Circ Support 2001;2:19–22
112. Jaski BE, Miller DA, Hoagland PM, Gordon JB, Chillcott SR, Stahovich MJ, Adamson RM, Baradarian S, Dembitsky WP. Assessment of recurrent heart failure associated with left ventricular assist device dysfunction. J Heart Lung Transplant 2005;24:2060–7
113. Moczar M, Houel R, Ginat M, Clerin V, Wheeldon D, Loisance D. Structural changes in porcine bioprosthetic valves of a left ventricular assist system in human patients. J Heart Valve Dis 2000;9:88–95
114. Dowling RD, Park SJ, Pagani FD, Tector AJ, Naka Y, Icenogle TB, Poirier VL, Frazier OH. HeartMate VE LVAS design enhancements and its impact on device reliability. Eur J Cardiothorac Surg 2004;25:958–63
115. Poirier VL. Inflow valve incompetence. J Congestive Heart Fail Circ Support 2001;2:23–5
116. Akosah KO, Song A, Guerraty A, Mohanty P, Paulsen W. Echocardiographic evaluation of patients with a left ventricular device. ASAIO J 1998;44:M624–7
117. Catena E, Milazzo F, Pittella G, Paino R, Colombo T, Garatti A, Vitali E, Merli M. Echocardiographic approach in a new left ventricular assist device: Impella Recover 100. J Am Soc Echocardiogr 2004;17:470–3
118. Pretorius M, Hughes AK, Stahlman MB, Saavedra PJ, Deegan RJ, Greelish JP, Zhao DX. Placement of the TandemHeart percutaneous left ventricular assist device. Anesth Analg 2006;103:1412–13
119. Di Bella I, Pagani F, Banfi C, Ardemagni E, Capo A, Klersy C, Vigano M. Results with the Novacor assist system and evaluation of long-term assistance. Eur J Cardiothorac Surg 2000;18:112–16
120. Vitali E, Lanfranconi M, Bruschi G, Russo C, Colombo T, Ribera E. Left ventricular assist devices as bridge to heart transplantation: the Niguarda Experience. J Card Surg 2003;18:107–13
121. Minami K, El-Banayosy A, Sezai A, Arusoglu L, Sarnowsky P, Fey O, Koerfer R. Morbidity and outcome after mechanical ventricular support using Thoratec, Novacor, and HeartMate for bridging to heart transplantation. Artif Organs 2000;24:421–6
122. Kohmoto T, Oz MC, Naka Y. Late bleeding from right internal mammary artery after heartmate left ventricular assist device implantation. Ann Thorac Surg 2004;78:689–91
123. Fowler NO. Cardiac tamponade. A clinical or an echocardiographic diagnosis? Circulation 1993;87:1738–41
124. Kuvin JT, Harati NA, Pandian NG, Bojar RM, Khabbaz KR. Postoperative cardiac tamponade in the modern surgical era. Ann Thorac Surg 2002;74:1148–53
125. Smart K, Jett GK. Late tamponade with mechanical circulatory support. Ann Thorac Surg 1998;66:2027–8
126. Reilly MP, Wiegers SE, Cucchiara AJ, O’Hara ML, Plappert TJ, Loh E, Acker MA, St John Sutton M. Frequency, risk factors, and clinical outcomes of left ventricular assist device-associated ventricular thrombus. Am J Cardiol 2000;86:1156–9
127. Oz MC, Argenziano M, Catanese KA, Gardocki MT, Goldstein DJ, Ashton RC, Gelijns AC, Rose EA, Levin HR. Bridge experience with long-term implantable left ventricular assist devices. Are they an alternative to transplantation? Circulation 1997;95:1844–52
128. Schmid C, Weyand M, Nabavi DG, Hammel D, Deng MC, Ringelstein EB, Scheld HH. Cerebral and systemic embolization during left ventricular support with the Novacor N100 Device. Ann Thorac Surg 1998;65:1703–10
129. Miyake Y, Sugioka K, Bussey CD, Di Tullio M, Homma S. Left ventricular mobile thrombus associated with ventricular assist device: diagnosis by transesophageal echocardiography. Circ J 2004;68:383–4
130. Vignon P, Gueret P, Vedrinne JM, Lagrange P, Cornu E, Abrieu O, Gastinne H, Bensaid J, Lang RM. Role of transesophageal echocardiography in the diagnosis and management of traumatic aortic disruption. Circulation 1995;92:2959–68
131. Dworschak M, Wiesinger K, Lorenzl N, Wieselthaler G, Wolner E, Lassnigg A. Late aortic dissection in a patient with a left ventricular assist device. Jpn J Thorac Cardiovasc Surg 2001;49:395–7
132. Nicolson DG, Porto I, Westaby S, Boardman P, Banning AP. Spontaneous echocardiographic contrast in the ascending aorta mimicking the appearance of aortic dissection in a patient with a left ventricular assist device. Echocardiography 2004;21:193–5
133. de Jonge KC, Laube HR, Dohmen PM, Ivancevic V, Konertz WF. Diagnosis and management of left ventricular assist device valve-endocarditis: LVAD valve replacement. Ann Thorac Surg 2000;70:1404–5
134. Holman WL, Skinner JL, Waites KB, Benza RL, McGiffin DC, Kirklin JK. Infection during circulatory support with ventricular assist devices. Ann Thorac Surg 1999;68:711–16
135. Gordon RJ, Quagliarello B, Lowy FD. Ventricular assist device-related infections. Lancet Infect Dis 2006;6:426–37
136. Baddour LM, Bettmann MA, Bolger AF, Epstein AE, Ferrieri P, Gerber MA, Gewitz MH, Jacobs AK, Levison ME, Newburger JW, Pallasch TJ, Wilson WR, Baltimore RS, Falace DA, Shulman ST, Tani LY, Taubert KA; AHA. Nonvalvular cardiovascular device-related infections. Circulation 2003;108:2015–31
137. Simon D, Fischer S, Grossman A, Downer C, Hota B, Heroux A, Trenholme G. Left ventricular assist device-related infection: treatment and outcome. Clin Infect Dis 2005;40:1108–15
138. Barbone A, Pini D, Grossi P, Bandera A, Manasse E, Citterio E, Eusebio A, Silvaggio G, Settepani F, Municino A, Colombo P, Casari E, Ornaghi D, Gronda E, Gallotti R. Aspergillus left ventricular assist device endocarditis. Ital Heart J 2004;5:876–80
139. Rodigas PC, Meyer FJ, Haasler GB, Dubroff JM, Spotnitz HM. Intraoperative 2-dimensional echocardiography: ejection of microbubbles from the left ventricle after cardiac surgery. Am J Cardiol 1982;50:1130–2
140. Orihashi K, Matsuura Y, Hamanaka Y, Sueda T, Shikata H, Hayashi S, Nomimura T. Retained intracardiac air in open heart operations examined by transesophageal echocardiography. Ann Thorac Surg 1993;55:1467–71
141. Tingleff J, Joyce FS, Pettersson G. Intraoperative echocardiographic study of air embolism during cardiac operations. Ann Thorac Surg 1995;60:673–7
142. Leyvi G, Rhew E, Crooke G, Wasnick JD. Transient right ventricular failure and transient weakness: a TEE diagnosis. J Cardiothorac Vasc Anesth 2005;19:406–8
143. Pollock SG, Dent JM, Kaul S, Lake C. Diagnosis of ventricular assist device malfunction by transesophageal echocardiography. Am Heart J 1992;124:793–4
144. Slaughter MS, Silver MA, Farrar DJ, Tatooles AJ, Pappas PS. A new method of monitoring recovery and weaning the Thoratec left ventricular assist device. Ann Thorac Surg 2001;71:215–18
145. Farrar DJ, Holman WR, McBride LR, Kormos RL, Icenogle TB, Hendry PJ, Moore CH, Loisance DY, El-Banayosy A, Frazier H. Long-term follow-up of Thoratec ventricular assist device bridge-to-recovery patients successfully removed from support after recovery of ventricular function. J Heart Lung Transplant 2002;21:516–21
146. Delgado DH, Rao V, Miriuka SG, Al-Hesayen A, McIver J, Feindel CM, Cusimano RJ, Ross HJ. Explantation of a mechanical assist device: assessment of myocardial recovery. J Card Surg 2004;19:47–50
147. Hetzer R, Muller J, Weng Y, Wallukat G, Spiegelsberger S, Loebe M. Cardiac recovery in dilated cardiomyopathy by unloading with a left ventricular assist device. Ann Thorac Surg 1999;68:742–9
148. Gorcsan J III, Severyn D, Murali S, Kormos RL. Non-invasive assessment of myocardial recovery on chronic left ventricular assist device: results associated with successful device removal. J Heart Lung Transplant 2003;22:1304–13
149. Khan T, Delgado RM, Radovancevic B, Torre-Amione G, Abrams J, Miller K, Myers T, Okerberg K, Stetson SJ, Gregoric I, Hernandez A, Frazier OH. Dobutamine stress echocardiography predicts myocardial improvement in patients supported by left ventricular assist devices (LVADs): hemodynamic and histologic evidence of improvement before LVAD explantation. J Heart Lung Transplant 2003;22:137–46
150. Chen JM, Levin HR, Rose EA, Addonizio LJ, Landry DW, Sistino JJ, Michler RE, Oz MC. Experience with right ventricular assist devices for perioperative right-sided circulatory failure. Ann Thorac Surg 1996;61:305–10; discussion 311–13
151. Eltzschig HK, Mihaljevic T, Byrne JG, Ehlers R, Smith B, Shernan SK. Echocardiographic evidence of right ventricular remodeling after transplantation. Ann Thorac Surg 2002;74:584–6
152. Dandel M, Weng Y, Siniawski H, Potapov E, Lehmkuhl HB, Hetzer R. Long-term results in patients with idiopathic dilated cardiomyopathy after weaning from left ventricular assist devices. Circulation 2005;112:I37–45