Biventricular amputation for biventricular pulsatile assist device implantation in patients with severe ventricular septal perforation

Abstract

Complete ischaemic destruction of the cardiac apex as well as the majority of the ventricular septum is usually a lethal condition with no alternatives except mechanical circulation support and highly urgent heart transplantation. Depending on the mass of the necrotic and destructed myocardium, implantation of a ventricular assist device can be challenging due to insufficient tissue quality. We describe here a new approach to pulsatile Thoratec (Thoratec Corporation, Pleasanton, CA, USA) extracorporeal biventricular assist device implantation.

INTRODUCTION

Severe ventricular septal perforation (VSD) can be a fatal complication in patients with acute myocardial infarction. It is associated with a high mortality due to the structural disintegration of the myocardium. The therapeutic regimen includes either conservative treatment or surgical interventions—both with a high incremental risk [1]. The first successful surgical repair of a postinfarction VSD was reported by Cooley in 1957 [2]. The ultimate goal of surgical repair for VSD is to reconstruct normal ventricular and septal anatomy and to restore the best possible ventricular function. In selected patients with large myocardial infarcts including the ventricular septum and both ventricles, implantation of a ventricular assist device (VAD) can be the only reasonable option to save patients' lives [3]. Depending on the mass of the necrotic myocardium, implantation of a VAD can be challenging, due to insufficient tissue quality. We describe here a new approach to Thoratec extracorporeal pulsatile biventricular assist device implantation (BVAD).

PATIENT PRESENTATION

A 59-year old female patient was admitted to our centre in cardiogenic shock with high-dose intravenous catecholamine support. The patient was intubated and mechanically ventilated.

Emergency coronary angiogram showed total occlusion of the left anterior descending artery (LAD). Transoesophageal echocardiographic examination revealed severely impaired biventricular function with left ventricular ejection fraction of 15%. In addition, a large VSD of 3 cm in diameter was diagnosed. Percutaneous coronary intervention of the LAD was not possible by any means. The patients' status rapidly deteriorated with increasing inotropic support. Further instability required urgent femo-femoral extracorporeal membrane oxygenation (ECMO) implantation. An interdisciplinary heart team decision was made in favour of BVAD with subsequent evaluation for heart transplantation due to the patient's age, lack of comorbidities and the fatal clinical situation.

SURGICAL PROCEDURE

The operative set-up included complete sternotomy and standard cannulation for cardiopulmonary bypass. Cardiac arrest was achieved with Brettschneider cardioplegia. Large apical portions of both ventricles were necrotic (Fig. 1a). The cardiac apex was amputated and the VSD, which presented at a maximum diameter of 3 cm, was identified (Fig. 1b). All necrotic myocardium was resected in a circular fashion up beneath the valvular plane with a remaining depth of ventricular myocardium of ∼2 cm. In order to create sufficient-sized neo-ventricles to anchor the Thoratec inflow cannula, the LV was patched with a Dacron membrane of 10 × 8 cm using 3-0 running sutures with felt pledgets (Fig. 1c). The right ventricular cavity was patched with bovine pericardium (8 × 5 cm) in order to prevent thrombotic formation (Fig. 1d). Subsequently, a circular hole was created in the Dacron-formed neo-apex. A 28-mm graft prosthesis (Hemashield) was anastomosed to the orifice for positioning the left ventricular inflow cannula using a 4-0 Prolene running suture (Fig. 1e). The left ventricular outflow cannula was anastomosed to the ascending aorta in a standard fashion. The right ventricular inflow cannula was installed directly into the right atrium using locked purse string sutures. The right ventricular outflow cannula was anastomosed to the pulmonary artery (Fig. 1f). The extracorporeal pulsatile ventricles were de-aired and connected, and pulsatile perfusion was initiated. Left ventricular pulsatile flow of 5.5 l/min and right ventricular flow of 4.8 l/min were chosen, respectively. Weaning from cardiopulmonary bypass was uneventful, with stable patient haemodynamics. The patient was admitted to the ICU and subsequently evaluated for heart transplantation.

Figure 1:

Biventricular apex amputation with patch reconstruction and Thoratec biventricular assist device implantation (view from the assistant side). (a) Massive necrotic apex; (b) amputated LV and RV and necrotic septum; (c) neo-LV patch reconstruction; (d) Dacron patched neo-LV, neo-RV patched with bovine pericardium; (e) LVAD inflow cannula fixed into Dacron formed neo-LV (arrow); (f) RV inflow and outflow cannula (circle), LV outflow cannula (arrow).

DISCUSSION

Complete ischaemic destruction of the cardiac apex as well as the majority of the ventricular septum is a lethal condition with no alternatives except mechanical circulation support and highly urgent heart transplantation [3]. In cases with a large VSD that extends towards the valvular plain, a surgical ventricular patch restoration with subsequent implantation of a pulsatile VAD (Thoratec) might be an option. We report here a new surgical approach for extracorporeal BVAD through the creation of a neo-apex after extensive myocardial resection. Surgery was successfully performed as described with no adverse event whatsoever. Haemodynamic stability of the patient was achieved with sufficient assist device performance.

Biventricular pulsatile assist device implantation represents a standard treatment therapy in patients with acute end-stage heart failure, irrespective of aetiology. Surgical implantation of the assist device inflow cannula to the ventricular apex, is, however, dependent on sufficient tissue quality and quantity. In cases of inappropriate anatomical conditions due to severe myocardial damage and necrosis, direct anastomosis of the assist device cannulas can be challenging or even impossible. However, successful implantation following surgical ventricular restoration with the use of a Dacron patch has been previously described to overcome this limitation [4]. This regimen creates enough tissue for anastomosis of the inflow cannula after elongation of the proximal portion using an interponated standard vascular prosthesis. Subsequent implantation of the right VAD in a standard fashion accounted for right ventricular failure.

CONCLUSION

Neo-apex creation after complete biventricular amputation facilitates BVAD (Thoratec). This technique can be of additional use in cases of extensive irreversible myocardial damage.

Conflict of interest: none declared.