The C-Pulse Heart Assist System (Eden Prairie, MN) is an extravascular, diastolic counterpulsation circulatory support device for patients with refractory NHYA Class III/ambulatory class IV heart failure symptoms. It comprises a balloon-cuff (Figure 1) which is implanted around the ascending aorta that is synchronized to inflate during ventricular diastole. The system eliminates the need for systemic anticoagulation, significantly reduces the risk of bleeding and overcomes the problem of device thrombosis.1 However, clinical efficacy is dependent on maintenance of residual myocardial function. We describe a case of a patient who presented with ischemic cardiomyopathy in end-stage heart failure and received the C-Pulse System. However, due to deterioration in cardiac function the system had to be upgraded to a full-support left ventricular assist device (LVAD) after 4 months.
A 55 year old man was admitted with severe ischemic cardiomyopathy in end-stage heart failure following anterior myocardial infarction 12 years previously. Comorbidities included type 2 diabetes mellitus and history of thyrotoxicosis attributed to amiodarone treatment for permanent atrial fibrillation. Cardiac catheterization showed a patent right coronary artery (RCA) and ramus circumflexus but occlusion of LAD with no options for revascularization. Despite CRT-D, cardiac catheterization showed a cardiac index of 1.48 ml/min/m2. After recompensation, trans-thoracic echocardiography showed an enlarged left ventricle with severe global impairment and a left ventricular ejection fraction of 25% and a normal-sized right ventricle (RV) with reasonable RV free wall motion and a tricuspid annular plane systolic excursion (TAPSE) of 15 mm. He was discharged home on medical therapy with orthopnea, dyspnea, and fatigue. Subsequently, he was scheduled for elective implantation of C-Pulse System as a bridge to transplantation. Having met OPTIONS study (ongoing prospective, multi-center, open label post market study) inclusion criteria, the C-Pulse device was implanted through a median sternotomy without cardio-pulmonary bypass (CPB). The patient was discharged home in clinically stable condition on postoperative day (POD) 22. The 6 minute walk test distance increased from baseline of 205 to 403 m on POD 29. Two months later, an ECG performed during a scheduled outpatient appointment showed multifocal ventricular ectopics. Due to amiodarone intolerance, beta-blocker therapy was uptitrated and the CRT-D pacing rate was increased in an attempt to control ventricular ectopy. However, the problem persisted, and the patient showed increasing symptoms of nausea and fatigue. The ventricular ectopy limited the efficacy of C-Pulse therapy exacerbating the heart failure symptoms. It was concluded that implantation of a full support LVAD was the only viable treatment option. The explantation of the C-Pulse Heart System and the upgrade to a full support HeartWare LVAD system was performed through a redo sternotomy (Figure 2) 4 months after initial surgery. Femoro-femoral CPB was instituted. Intraoperatively, dense adhesions were encountered, particularly between the aortic wall and the C-Pulse cuff leading to a very long dissection time before the cuff could be explanted (Figure 3). As the ascending aorta was short, the outflow graft of the HeartWare LVAD had to be anastomosed to the cuff balloon region of the aorta. This was achieved without any technical problems. Six weeks later, the patient was discharged in a stable clinical condition on LVAD support. One hundred and thirteen days after HeartWare ventricular assist device (HVAD) implantation, the patient had a suspected pump thrombosis episode characterized by elevation in 1) pump power (5.8 W at 2,600 rpm), 2) plasma hemoglobin (2.6 g/L), and 3) lactate dehydrogenase (6,107 U/L) levels despite good anticoagulation control. The LVAD was exchanged 2 days later and pump thrombosis was confirmed at explant. The patient was discharged 82 days later. A repeat computed tomography of the thorax 6 months after LVAD implantation showed no evidence of deterioration of the outflow graft anastomosis (Figure 4).
Ongoing technological improvements in the field of mechanical circulatory support have led to the introduction of smaller and more reliable continuous-flow blood pumps with improved morbidity and mortality.2 The concept of chronic partial flow support has been shown to be effective and may even be suitable for inotropic-dependent patients and those in cardiogenic shock.3 In contrast to partial support LVADs such as the Synergy CircuLite Micropump, the C-Pulse System is an extravascular counterpulsation device which avoids the complications associated with blood contact.4 The identification of patients suitable for partial support whose ventricular function will be sustained long enough to justify the support strategy remains challenging. Potential advantages of partial support device implantation include a shorter, less traumatic surgical procedure, and reduced risk of acquired aortic regurgitation due to continuous aortic valve leaflet motion. However, the consequence of failure of partial support is the need to upgrade to a full flow LVAD with increased risks (such as the risk of HLA sensitization although this was not the case in this report), increased burden to the patient, and incremental treatment.5 However, it should be highlighted that full flow LVADs are also associated with inherent risks.6 It is conceivable that a positive response to preoperative intraaortic balloon therapy would be predictive of long-term benefit from chronic counterpuslation. However, this strategy does not form part of the clinical study to which the patient was recruited.
If an upgrade from C-Pulse to full flow support is required, additional care has to be taken during the dissection of the ascending aorta and while performing the outflow-graft-to-aorta anastomosis as the impact of C-Pulse cuff action on aortic wall integrity in the context of anastomotic surgery has not been fully characterized. Cheng et al. reported recently a case on a 58 year old woman with nonischemic cardiomyopathy who received a heart transplant 21 months after C-Pulse implantation.7 Following histopathological analysis, the native ascending aorta showed only mild neutrophilic inflammation with maintenance of aortic wall structural integrity. However, a case of aortic rupture in a patient after C-Pulse implantation has been reported although this was attributed to severe mediastinitis.1 Our findings concur with those of Abraham et al.1 and Cheng et al.6 by showing that that the inflatable cuff action did not compromise the structural integrity of the aortic wall even in a patient with ischemic cardiomyopathy.7
Conversely, if prolonged partial support can be effectively implemented, it is conceivable that the patient may be less susceptible to acquired aortic regurgitation than those receiving a continuous-flow LVAD8 due to continuous valve leaflet motion.
Our preliminary experience suggests that it is feasible and safe to perform outflow graft anastomosis to the aortic wall adjacent to the C-Pulse cuff balloon. Further evidence is required to comprehensively evaluate the impact of the action of the C-pulse cuff on the aortic anastomotic integrity in the context of LVAD implantation.
1. Abraham WT, Aggarwal S, Prabhu SD, et al.C-Pulse Trial Study GroupAmbulatory extra-aortic counterpulsation in patients with moderate to severe chronic heart failure.JACC Heart Fail20142526533
2. Slaughter MS, Rogers JG, Milano CA, et al.HeartMate II InvestigatorsAdvanced heart failure treated with continuous-flow left ventricular assist device.N Engl J Med200936122412251
3. Sabashnikov A, Popov AF, Bowles CT, et al.Outcomes after implantation of partial-support left ventricular assist devices in inotropic-dependent patients: Do we still need full-support assist devices?J Thorac Cardiovasc Surg2014148111521; discussion 1021
4. Capoccia M, Bowles CT, Pepper JR, Banner NR, Simon AREvidence of clinical efficacy of counterpulsation therapy methods.Heart Fail Rev201520323335
5. Zeriouh M, Sabashnikov A, Banner NR, Simon AR, Popov AFUpgrade ambulatory extra-aortic counterpulsation to full-support LVAD.JACC Heart Fail20153342343
6. Cheng A, Monreal G, William ML, Sobieski M 2nd, Slaughter MSExtended extra-aortic counterpulsation with the C-Pulse device does not alter aortic wall structure.ASAIO J201460e5e7
7. Abraham WT, Aggarwal S, Prabhu SD, et al.C-Pulse Trial Study GroupReply: Upgrade ambulatory extra-aortic counterpulsation to full-support LVAD.JACC Heart Fail20153343344
8. Patil NP, Mohite PN, Sabashnikov A, et al.Does postoperative blood pressure influence development of aortic regurgitation following continuous-flow left ventricular assist device implantation?†.Eur J Cardiothorac Surg201649788794