A 68-year-old man with decompensated nonischemic cardiomyopathy was transferred to our institution for evaluation of heart transplantation or mechanical circulatory support candidacy. He was stabilized in the intensive care unit with intubation, diuresis, and inotropic support. Transthoracic echocardiogram revealed severely depressed right ventricular (RV) and left ventricular function (left ventricular ejection fraction, 10%), severe mitral regurgitation, as well as a mildly dilated right atrium (RA) with a large, mobile mass consistent with thrombus/embolus. Emergent percutaneous atrial thrombectomy by cardiac surgery with transesophageal echocardiography (TEE) guidance was planned, given the patient’s high operative risk and likelihood of mortality if distal embolization to the pulmonary artery (PA) occurred.
Intraoperative TEE confirmed the presence of a large, free-floating, worm-like, mobile thromboembolus within the RA with reduced RV function (Figure 1; Supplemental Digital Content 1, Video 1, http://links.lww.com/AA/B286). No embolic material was visualized in the RV or PA, and McConnell sign was not present. Cannulation for venovenous extracorporeal bypass was established through right and left femoral veins for use with the AngioVac™ (Angiodynamics, Vortex Medical Inc., New York, NY) venous drainage cannula. The venous cannula was sequentially advanced over a wire (Fig. 2A) until visualized at the inferior vena cava (IVC)–RA junction, and bypass circulation was initiated. The cannula was advanced from the IVC, through the RA (Figure 2B and 2C; Supplemental Digital Content 2, Video 2, http://links.lww.com/AA/B287) and into superior vena cava (SVC) to remove all visible thrombus in the RA (Figure 2D; Supplemental Digital Content 3, Video 3, http://links.lww.com/AA/B288). The patient remained hemodynamically stable receiving dobutamine and dopamine throughout the procedure. Unfortunately, he was not deemed suitable for heart transplant or mechanical circulatory support because of multiple medical comorbidities and he died 14 days after the procedure. Written consent for publication was unable to be obtained because of the patient’s death, and no family member was available to provide consent. IRB approval for publication of this case was obtained.
The AngioVac balloon-tipped venous drainage cannula is a coil-reinforced cannula designed for evacuation of soft, fresh thrombi or emboli in conjunction with venovenous extracorporeal bypass (Fig. 3A). Venous inflow through the AngioVac catheter may be established in the contralateral femoral vein (as in this case) or the SVC (as depicted in Fig. 3B), depending on anatomic features influencing site selection, e.g., local site thrombosis). The inflow cannula has a single orifice at the termination of the catheter, which must be maneuvered into close approximation of the material to be extracted. In the event of distal embolization during cannula manipulation, pulmonary embolectomy may be possible by advancement into the PA.1 The variable circuit flow rate generates suction at the cannula tip, and solid material is trapped through an inline filter before blood return to the patient (Fig. 3B). In this case, fluoroscopy was not used, although a multidisciplinary team commonly performs these procedures in a hybrid operating room with fluoroscopic capability.
Essential steps for TEE guidance include the assessment of wire/cannula placement, monitoring for inadvertent damage of cardiac structures, and assessing successful removal of the mass. Placement of the inflow cannula is guided by a wire, which is readily visualized on TEE (Supplemental Digital Content 2, Video 2, http://links.lww.com/AA/B287). It may be useful to visualize the intrahepatic IVC to observe the cannula position during advancement. By advancing the TEE probe to a transgastric position and turning to the right, the liver and IVC are visualized; the multiplane angle is then rotated until the IVC is viewed in long axis (20°–70°). In the case presented here, inadvertent instrumentation of the mass was avoided by only advancing the cannula to the SVC/RA junction. The wire was removed, the balloon was inflated, and bypass flow was initiated, which successfully evacuated the majority of visualized thrombus (Supplemental Digital Content 2, Video 2, http://links.lww.com/AA/B287). Bypass flow was then suspended to place a wire to advance the cannula into the SVC. Bypass was resumed, and the cannula slowly pulled back to collect any remaining thrombus (Supplemental Digital Content 2, Video 2, http://links.lww.com/AA/B287). TEE imaging of the cannula is facilitated by the echogenic coils present in the AngioVac; the balloon tip is readily visualized extending beyond the coils when partially/fully inflated; struts that support the opening of the catheter are seen flaring out (Fig. 2C).
During bypass, the occurrence of low flow/no flow may indicate obstruction of the cannula funnel, requiring withdrawal and repositioning. Obstruction may occur during aspiration of a large thrombus or inadvertent aspiration of the RA wall or tricuspid valve, which can be noted by TEE. The vigilant monitoring of cannula tip position is essential to avoid rupture of cardiac chambers, damage to the tricuspid valve, or dislodgement of an implanted device (e.g., pacemaker wire). Distal embolization may occur if the mass is dislodged during manipulation. The reader is referred to previous Echo Rounds discussing the features of acute right heart embolus,2 including McConnell sign.3 The precarious nature and significant potential for mortality associated with a highly mobile right heart thromboembolus (or pulmonary embolism-in-transit) justifies urgent intervention, particularly if embolism has not already occurred.4 TEE guidance is crucial for all portions of an AngioVac extraction procedure.
Clinician’s Key Teaching Points
By Kent H. Rehfeldt, MD, Roman M. Sniecinski, MD, Martin J. London, MD
- The AngioVac system is designed to remove embolic material or other masses from the right atrium (RA), right ventricle, and pulmonary artery. It uses a balloon-tipped, wire-reinforced cannula that is inserted into either the femoral vein or internal jugular vein and advanced into the right heart. Blood is aspirated into the AngioVac cannula, passes through an in-line filter designed to remove the mass, and then is returned by means of a centrifugal pump into the contralateral femoral vein.
- Transesophageal echocardiography (TEE) can readily visualize the AngioVac cannula, allowing for real-time guidance during the procedure. When the device is placed via the femoral vein, a modified transgastric view with rightward probe rotation and a multiplane angle of 20° to 70° can visualize it advancing past the RA–inferior vena cava junction into the RA. Similarly, a midesophageal bicaval view would be helpful to monitor cannula advancement from the superior inferior vena cava when an internal jugular vein placement is selected.
- In this case, an isolated RA thrombus was noted in a patient with severe biventricular systolic dysfunction. The AngioVac cannula was advanced from the femoral vein into the heart and then activated. TEE was critical in confirming proper placement and monitoring for aspiration of the RA thrombus.
- In addition to evaluating the cannula placement, TEE can diagnose iatrogenic damage to the right-sided valves or dislodgment of intracardiac devices such as pacing leads. If a sudden low-flow condition develops during this venovenous bypass procedure, TEE can determine whether the AngioVac cannula has become occluded by the target thrombus or whether the device is inappropriately aspirating the RA wall or the tricuspid valve.
Name: Rebecca M. Gerlach, MD, FRCPC.
Contribution: This author was a fellow in cardiothoracic anesthesiology at Cedars-Sinai Medical Center and participated in the intraoperative management of the presented case. This author also participated in the preparation of the manuscript and attests to the originality of the current information.
Attestation: Rebecca M. Gerlach approved the final version of this manuscript.
Name: Danny Ramzy, MD.
Contribution: This author performed the surgical intervention and participated in the preparation of the manuscript and attests to the originality of the current information.
Attestation: Danny Ramzy approved the final version of this manuscript.
Name: Lorraine Lubin, MD.
Contribution: This author participated in the preparation of the manuscript and attests to the originality of the current information.
Attestation: Lorraine Lubin approved the final version of this manuscript.
Name: Antonio Hernandez Conte, MD, MBA.
Contribution: This author was the attending anesthesiologist responsible for the management of the current case and participated in the preparation of the manuscript and attests to the originality of the current information.
Attestation: Antonio Hernandez Conte approved the final version of this manuscript.
This manuscript was handled by: Martin J. London, MD.
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