Implantation of a left ventricular assist device (LVAD) as a bridge to recovery or transplantation is a widely accepted treatment modality.1 Despite the clinical benefit of LVAD usage, right ventricular (RV) failure after LVAD implantation continues to be a major postoperative problem. Most of these patients are extremely ill and present with coagulopathy, renal failure, and hepatic congestion. Although some patients recover successfully on medical right heart supporting therapies including inotropes, phosphodiesterase inhibitors, or inhaled nitric oxide, others require mechanical circulatory support.2,3 Current options for mechanical assistance include venoarterial extracorporeal membrane oxygenation (ECMO), centrifugal pump as an RV assist device (RVAD) and pulmonary artery balloon pump.4 However, it is well documented that patients with biventricular assist devices have poorer outcomes than those requiring isolated LVAD support.5 In fact, RV failure requiring RVAD implantation is the most significant risk factor for mortality in LVAD patients.6 To avoid secondary RV failure and the upgrade to a biventricular long-term assist device, temporary RV assist may serve as alternative.
In this report, we describe our experience with a transcutaneous RVAD as a temporary RV support to avoid secondary RV failure and the upgrade to a biventricular long-term assist device after LVAD implantation, which does not necessitate rethoracotomy for explantation.
Materials and Methods
After approval by the local ethics committee, we reviewed data from three patients with profound cardiogenic shock secondary to acute or chronic heart failure, who were provided with a percutaneous extracorporeal life support (ECLS) system on an emergency basis by the femoral vessels before LVAD implantation. After stabilization, an LVAD was implanted. To avoid secondary RV failure, the ECLS was switched to a transcutaneous RVAD as a temporary RV support.
The ECLS system (Cardiohelp, Maquet CP, Hirrlingen, Germany) is a lightweight (10 kg), ultracompact, and portable extracorporeal perfusion system. A membrane oxygenator, a centrifugal pump, arterial and venous pressure sensors, temperature monitoring, and measuring devices for mixed venous saturation and hemoglobin are put together to create a single exchangeable component. As all blood contact surfaces of the system are heparin coated with the BIOLINE technique (Maquet CP), systemic anticoagulation can be kept at a minimum. The effect of heparin was measured by the activated partial thromboplastin time (aPTT), ideally between 50 and 60 seconds. In all patients, a 23-Fr cannula (BE-PVS 2338, Maquet CP) was percutaneously inserted into the right femoral vein using Seldinger technique. The arterial return was achieved with a 17-Fr cannula by the left femoral artery.
After stabilization and excluding contraindications for transplantation, a pneumatically driven paracorporeal LVAD (80 ml pump chamber, Berlin Heart EXCOR, Berlin, Germany) was implanted using a standard approach between the left ventricular apex and the ascending aorta (Figure 1).
RV failure was determined clinically and included inadequate cardiac output and systemic pressure despite large doses of inotropes and vasopressor agents, hypokinetic RV free wall motion by intraoperative echocardiography, and increased central venous pressure (CVP) with or without new-onset moderate-to-severe tricuspid regurgitation.
As it is difficult to evaluate the RV function during ECLS support, we decided to change the venoarterial ECLS to a venoarterial RVAD immediately after LVAD implantation to avoid secondary RV failure. The arterial cannula was removed from the femoral artery, and the femoral vein cannulas were left in situ and used as inflow. An 8-mm Dacron graft (Vascutek-Gelweave, Inchinan, UK) was anastomosed end-to-side to the main pulmonary artery with a 5-0 polypropylene running suture using a Satinsky side clamp and passed through a subxiphoid exit, where the outflow cannula (23 Fr) was inserted. The graft is tied tightly around the cannula outside the chest with umbilical tapes and secured firmly to the chest wall with multiple heavy sutures. For mechanical circulatory support, cannulae were connected to a centrifugal pump (Rotaflow, Maquet CP). An integration of an oxygenator into the RVAD was possible, when the pulmonary function was impaired. The chest was definitely closed. The operating room was left with an LVAD flow between 4 and 5 L/min and an RVAD flow between 2 and 3 L/min. After 6 hours without bleeding, we started anticoagulation with heparin (aPTT 50–60 seconds), and we maintained this anticoagulation protocol till RVAD explantation. Long-term anticoagulation consisted of coumarin, together with a platelet aggregation inhibitor at a low dosage.
After an uneventful recovery, the RVAD was weaned under echocardiography control and surveillance of CVP and LVAD flow. RV recovery included no escalation of inotropic support, maintenance of a low CVP (<15 mm Hg), and return of transaminases and creatinine to near-normal levels. Before explantation of the RVAD, its flow was decreased to 1 L/min and the hemodynamic status reassessed. The pump lines were clamped, and skin exit of the graft was widely prepared and draped. Gentle traction on the graft allowed the redundant portions from inside the chest to be exposed. The umbilical tapes were cut, and the cannula was removed. The graft was then divided at the skin level and oversewn. By delivering the redundant portion, the graft was sterile at the point of division. The closed stump was allowed to retract into the oblique chest wall track, and the skin incision was loosely closed. Removal of the inflow femoral was simple with manual compression of the groin.
A 51-year-old man was admitted to our institution with cardiogenic shock due to end-stage dilated cardiomyopathy. Echocardiography showed a dilated left and right ventricle with and a poor contractility despite inotropic and antiarrhythmic support. He was immediately provided with a percutaneous ECLS system by the femoral vessels. On postoperatively day (POD) 8, an Excor l LVAD was implanted. The venoarterial ECLS was terminated and rearranged as RVAD system. The chest was definitely closed. The operating room was left with an LVAD flow of 4.5 L/min and RVAD flow of 2.5 L/min. The patient was extubated 2 days later. The RVAD was successfully weaned after 6 days, the inflow cannula was taken out, and the outflow cannula was removed under local anesthesia. After removal of the RVAD, no signs of right heart failure occurred. Native cardiac function continued to be poor, so that the patient was listed for cardiac transplantation (Figure 2).
A 38-year-old man was referred to our institution after massive myocardial infarction owing to occlusion of the left anterior descending coronary artery (LAD). He had been treated with a drug-eluting stent into the LAD and was in cardiogenic shock. He required mechanical respiratory support and high doses of inotropes. At the referral center, the ECLS system Cardiohelp was implanted by the femoral vessels, and the patient then transported by car to our center. As cardiac function did not recover despite an ECLS support of 3–4 L/min, an LVAD (EXCOR) was implanted using a standard approach after 9 days. Similar to our first patient, the venoarterial ECLS was switched to a venoarterial RVAD to avoid secondary RV failure in the immediate postoperative period. In contrast to the first patient, the pulmonary function was severely impaired. Hence, an oxygenator was integrated into the RVAD, which was in fact a venoarterial ECMO. At the end of the procedure, the patient was hemodynamically stable with an LVAD flow between 4 and 5 L/min, RVAD flow between 2 and 3 L/min, and low doses of inotropes. The native lung function improved within 7 days; the RVAD was weaned and removed after 15 days. With the aid of a tracheostomy, respirator therapy could be terminated 4 weeks after LVAD implantation. The patient was listed as a cardiac transplant candidate (Figure 2).
The third patient was a 42-year-old man with cardiogenic shock and severe multiorgan failure due to massive myocardial infarction after occlusion of the left circumflex artery (LCX). After 20 minutes of mechanical cardiopulmonary resuscitation, he had been treated with a drug-eluting stent into the LCX. An ECLS was implanted by the femoral vessels as in the former cases to transport him to our institution. After stabilization and excluding contraindications for transplantation, an LVAD (EXCOR) was implanted using a standard approach after 6 days of ECLS support. Similar to other patients, the ECLS was changed to a RVAD immediately after LVAD implantation. An oxygenator was not integrated into the RVAD. Also, this patient was at the end of the procedure hemodynamically stable with LVAD flow between 4 and 5 L/min and RVAD flow between 2 and 3 L/min. Also, this patient showed no signs of right heart failure. Unfortunately, the patient died due to internal bleeding 14 days after LVAD implantation (Figure 2).
In the treatment of end-stage heart failure, LVADs have gained broader application not only as a bridge to heart transplantation but also as a bridge to recovery and permanent support.1 Despite the clinical benefit of LVAD usage, RV failure after LVAD implantation continues to be a major postoperative problem. The incidence of RV failure for patients after implantation of a long-term LVAD is approximately 30%.2 Also, for ECLS-supported patients, the incidence of RV failure in LVAD implants is relatively high (66.7%).7 Previous studies have reported poor outcomes in LVAD recipients with significant RV dysfunction8 and in case of RVAD placement after LVAD implantation.3 Most of these patients are in a critical condition and already have serious complication such as bleeding, coagulopathy, pulmonary hypertension, liver failure, or other end-stage organ dysfunction. For this reason, it is important to provide RV support early and with minimal trauma. Current options for mechanical assistance include venoarterial ECMO, centrifugal pump as a RVAD, and pulmonary artery balloon pump.4 The right atrium to pulmonary artery bypass using an ECLS circuit or paracorporeal devices is a widely accepted modality. The disadvantage of this technique is the reoperation to remove the right atrial and the pulmonary artery cannulas with additional risk for bleeding, wound infection, and device contamination. Peripheral venoarterial ECMO for RV support is another alternative. However, the ECMO flow in this approach is limited and may carry an additional thromboembolic and bleeding risk for the patients. The pulmonary artery balloon pump support is only suitable for a short time period in patients with up to a 50% reduction in optimal RV performance. This method is unsuitable for extended use and is not as reliable as the RVAD support.9
Previous reports have demonstrated the feasibility of minimally invasive RVAD insertion using different approaches. Stepanenko et al.10 described implantation of temporary RVAD by a left lateral thoracotomy. Cohn et al. described RVAD insertion through vessel grafts with bedside removal, whereas Minami et al.11,12 described cannulation of the outflow graft through the right pulmonary artery between the ascending aorta and the superior vena cava using Seldinger technique. The basic idea of the transcutaneous RVAD by sternotomy was devised by Strauch et al.13 in 2004. The concept was seen as especially useful for patients with RV failure after LVAD implantation.
In this report, we describe our experience with three patients with cardiogenic shock and severe multiorgan failure who were supported initially with a percutaneous miniaturized ECLS (Cardiohelp) system. After stabilization, LVADs were implanted using a standard approach. The preoperative prediction of RV function after LVAD implantation is crucial for device selection and patient outcome, but it is still not well established. As it is difficult to evaluate the RV function during ECLS support, we decided to change the venoarterial ECLS to a venoarterial RVAD immediately after LVAD implantation. The graft of the outflow cannula was simply anastomosed end-to-side to the pulmonary artery before termination of the ECLS support and then guided outside the chest. The inflow cannula was left in the right femoral vein. Both cannulae were connected to a Rotaflow pump. We were able to achieve adequate blood flows up to 6 L/min. The (additional) surgical procedure takes only a short period of time. Postoperatively, a meticulous cannula side wound care was practiced to prevent any infection. After an uneventful recovery, the RVAD was weaned under echocardiography control and surveillance of CVP and LVAD flow. Right ventricular function remained intact in all cases. Infection and bleeding are the most frequent complications after RVAD implantation, which can be alleviated by transcutaneous temporary RV support. The described approach diminishes the risk of bleeding, because this less invasive technique does not require extensive dissection of cardiac adhesions. During weaning from RVAD, the venous inflow cannula is easy to remove, no right atrial manipulation is needed.13 The outflow cannula is pulled out of the tube graft; the latter is ligated and buried in the abdominal wall. The prosthesis can be removed on further surgery as at the time of transplantation. This technique is comparable with the mediastinal implantation of IABP by means of a graft sutured to the side of the aorta. The device is removed transcutaneously, and the graft is ligated and subsequently thromboses.14
Most of the currently available devices require full-dose systemic anticoagulation. In contrast, our RVAD system (BIOLINE coating) runs with a “low-dose” heparin infusion that does not exceed normal antithrombotic anticoagulation of the intensive care patient.
Our cases are of particular interest because the duration of RVAD support was relatively long (up to 15 days) in comparison with previously reported cases. Another advantage is that an integration of an oxygenator into the RVAD was possible, when the pulmonary function was impaired. None of the typical complications related to RVAD, such as cannula thrombosis, bleeding, or hemolysis were observed. Also, infections associated with the Dacron prosthesis during or after support were not observed.
Nevertheless, our report has some limitations. The report is a single-center experience, and the number of patients is small.
In conclusion, the transcutaneous RVAD provides effective temporary mechanical circulatory support and thus avoids secondary RV failure after LVAD implantation. The ease of device implantation, weaning, and explantation justifies a liberal use.
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