The therapeutic value of left ventricular assist devices (LVADs) as either a bridge-to-transplant or destination therapy in heart failure patients is now well established.1–31–31–3 There is an increase in the morbidity and mortality after LVAD implantation in patients who have undergone one or more previous median sternotomies.4 New surgical approaches including left thoracotomy and left subcostal and bilateral anterior thoracotomy have been used to minimize the morbidity of LVAD implantation.5–75–75–7 However, prior sternotomy contraindicates their use or requires alternate targets for the outflow graft because of poor access to the ascending aorta due to adhesions between the dilated heart and back of the sternum. Surgical robotics has proven to enhance access and dexterity in surgical fields such as the retrosternal space in a redo chest that are difficult to access using conventional methods.8 Specifically for redo cardiac surgery, robotics enables access to be achieved through “virgin territory” or areas such as the right chest that have not been previously manipulated and have no surgical scarring. Enhanced magnification and exposure allows the scar between the sternum and the heart to be lysed in a far more hemostatic and precise manner than through a repeat sternal splitting approach. We applied our expertize in the use of robotics in redo cardiac surgery toward the implantation of a HeartWare ventricular assist device (HVAD, HeartWare International, Framingham, MA) in three patients awaiting heart transplant, one of whom is specifically outlined below.9 Furthermore, we compared the outcomes of all patients at our institution who underwent LVAD implantation via either a traditional sternotomy or a robotic-assisted procedure.
A 59-year-old woman with systemic and pulmonary hypertension, type 2 diabetes mellitus, and nonischemic dilated cardiomyopathy presented with progressively worsening heart failure (New York Heart Association class IV and American College of Cardiology stage D) despite optimal medical therapy with angiotensin-converting enzyme inhibitors, beta-blockers, spironolactone, and aggressive diuretic therapy. Her cardiac surgical history was notable for resection of atrial myxoma and mitral valve repair via a median sternotomy approach. Despite surgical correction, she progressively developed severe mitral regurgitation and worsening dilated cardiomyopathy. She underwent cardiac magnetic resonance imaging, which confirmed severely dilated left ventricle (LV) with an ejection fraction of approximately 10% and nonviable myocardium. Therefore, HVAD implantation was recommended as a bridge-to-cardiac transplantation. She was taken to the operating room and underwent robotic-assisted HVAD implantation.
The HVAD was implanted using a robot-assisted bilateral minithoracotomy approach, similar to the procedure recently illustrated by Khalpey et al.9 First, transthoracic echocardiogram was initialized to visualize the LV apex, confirm LV dysfunction, and verify the absence of aortic insufficiency, intracardiac thrombus, patent foramen ovale, and right ventricular (RV) dysfunction.
After affirmation of these findings, a left minithoracotomy was performed through the fifth intercostal space (ICS), and the LV apex was dissected under transesophageal echocardiogram (TEE) guidance. Four-pledgeted ethibond 2-0 stitches were placed at the LV apex through the sewing ring, before a running prolene 4-0 for HVAD implantation. The device was then tunneled down to the right flank with a counter incision in the right subcostal midaxillary line. Standard femoral cannulation was completed for cardiopulmonary bypass (CPB). Using the da Vinci robot (Intuitive Surgical Inc., Sunnyvale, CA), robotic access to the right chest was gained through 1 cm incisions in the third, fifth, and seventh ICS anterior to the right anterior axillary line; anesthesia was maintained on single left lung ventilation. The right ventricle was dissected from the sternum with robotic arms, and a tunnel was fashioned to reach the left minithoracotomy. Then, the adhesions and fat surrounding the aorta and aortopulmonary window were dissected. With robotic assistance along the right heart extrapericardial space, a tunnel was created to minimize kinking of the outflow tube graft (10 Fr Dacron, HeartWare). The tube graft was allowed to fill and sized appropriately to the aorta. Standard CPB was then initiated. The O-ring of the HVAD was secured to the LV apex; hemostasis was achieved in a standardized manner; and the HVAD connection was secured. A separate right minithoracotomy (3 cm) was performed in the second ICS to approach the aorta. A partial occluding clamp was applied to the ascending aorta through this incision in the second ICS. Under direct visualization, the outflow graft was sewn to the aorta with running prolene 4-0 sutures. A deairing procedure was then performed anterograde and retrograde within the tube graft. Cardiopulmonary bypass was weaned as the heart filled and the HVAD rpm increased. Hemostasis was confirmed. Finally, TEE verified good RV function without intracardiac thrombus. Mediastinal and pleural drains were inserted, and standard closure of sites for surgical access was performed.
A total of three patients with previous cardiac surgeries have undergone HVAD implantation by the described technique at our institution (Table 1). Each had at least one previous sternotomy and was alive at their most recent follow-up visit.
The outcomes of patients undergoing LVAD implantation (n = 23) by either a redo sternotomy (n = 4) or a robotic approach (n = 6) at our institution were compared using a two-sample t-test with unequal variances for continuous outcomes and Fisher’s exact test for binary outcomes. Supporting findings established in previous literature, patients who underwent previous sternotomies required significantly more red blood cells intraoperatively than the nonredo sternotomy group (3.5 ± 1.0 vs. 1.7 ± 2.1; p ≤ 0.03).4,9
Patients receiving LVAD support by both the aforementioned technique and the other robotic techniques did not have an increased risk of thromboembolic events or valve-related problems. In addition, utilizing robotic assistance instead of traditional sternotomy resulted in a significant reduction in resource utilization after LVAD implantation, affirmed by comparing all patients who underwent robotic implantation (n = 6) with those who underwent implantation via traditional sternotomy approach (n = 17). The robotic group spent significantly less time in the hospital (36.0 ± 17.1 vs. 67.4 ± 34.2; p ≤ 0.01), required less fresh frozen plasma intraoperatively (2.2 ± 1.0 vs. 4.0 ± 2.9; p ≤ 0.04), less cryoprecipitate (0 ± 0 vs. 2.4 ± 3.7; p ≤ 0.02), and less platelets (0 ± 0 vs. 1.5 ± 2.6; p ≤ 0.03) postoperatively than the nonrobotic group.10
For patients with previous cardiac surgery, re-entry via median sternotomy is challenging and poses significant risk of injury to the underlying heart and great vessels that are often densely adherent to the previous sternotomy wound.11 The availability of miniaturized HVAD and improvement in robotic techniques has resulted in innovative techniques for LVAD placement in high-risk patients with previous median sternotomy and its associated complications. Umakanthan et al.12 recently implanted an HVAD through a left thoracotomy approach with the outflow graft anastomosis performed onto the descending aorta. This approach obviates the need for dissecting thick tissue adhesions retrosternally and surrounding the ascending aorta, but results in altered patterns of flow in the aortic arch that can lead to stasis and the risk of thrombus formation.12 Our less invasive robotic technique differs in that we are able to duplicate the arrangement of the conventional operation with the outflow graft anastomosed onto the standard location on the ascending aorta.13
Despite several advantages, our approach has limitations. It is a technically complex feat to operate within the relatively tight and constrained chest cavity on patients who have end-stage heart failure. Limited surgical access hinders the ability to directly inspect the heart and surgical field. The potential for sudden bleeding, either from the heart or the vascular sources such as the inferior mesenteric artery, cardiac fibrillation, myocardial ischemia, and hemodynamic collapse can be difficult to diagnose and treat in this setting, particularly when the bulky arms of the robot are docked to the patient and severely hindering access. Best practices in team communication must be developed that facilitate early identification of impending problems and the appropriate responses. This includes efforts to optimize team communication, heighten “situational awareness,” and develop standardized and reliable protocols for responding to intraoperative events. Concerns about overall safety may be demoralizing to the team, which can be a latent risk factor for complications. Therefore, team morale is a critical focus of assuring the safety of the procedure. Developing and validating strategies for rapid progress through the learning curve and gaining “buy in” about the benefits of less invasive surgery is critical for success.
If validated by our ongoing experience with this procedure, robotic assistance may improve the safety and cost-effectiveness of reoperative LVAD surgery in addition to minimizing blood product use in bridge-to-transplant patients.
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