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© 2004 European Association of Cardio-Thoracic Surgery
Successful replacement of malfunctioning TCI HeartMate LVAD with DeBakey LVAD as a bridge to heart transplantation
a Department of Cardiac Surgery, Niguarda Hospital, P.zza Ospedale Maggiore 3, 20100 Milan, Italy
* Corresponding author. Tel.: +39-2-6444-2565; fax: +39-2-6444-2566 Received January 24, 2004; received in revised form June 1, 2004; accepted June 2, 2004
Congestive heart failure is the leading cause of hospitalization and death in the developed world and affects about 0.4–2% of the adult population [Ann Thorac Surg 1999;68:637–40]. Heart transplantation remains the most effective therapy for end-stage heart disease, but the shortage of donors has led to increasing interest in other surgical options, especially ventricular assist devices (VAD). Several VADs are available to bridge patients to transplantation [N Engl J Med 2001;345:1435–43], including pulsatile devices like the HeartMate (HeartMate, Thoratec, Pleasanton, CA) and Novacor (World Heart, Netherlands), and the DeBakey VAD (MicroMed Technology, Inc., Houston, TX), which is an electromagnetically driven implantable titanium axial flow blood pump designed for left ventricular support. Despite technical improvements, VADs still are associated with serious complications. We reporte a successfull case where we replaced a TCI HeartMate with a DeBakey VAD because of a serious pocket infection, deterioration and failure of the inflow valve.
Key Words: Mechanical circulatory assistance; Infection; Heart transplantation
A 47-year-old woman presented with a history of type II diabetes mellitus, arterial hypertension and post-partum dilated cardiomyopathy in 1987. In 2000 she had an implantable cardioverter defibrillator implanted for recurrent episodes of ventricular tachycardia. By the end of January 2002, the patient clinically deteriorated with episodes of congestive heart failure (CHF) and recurrent ventricular arrhythmias. Despite maximal IV inotropic support, she progressed to cardiogenic shock and a TCI Heartmate was implanted at an outside Center. The perioperative period was complicated by haemorrhage requiring re-thoracotomy and massive transfusion of blood products. Four months later, the patient developed a pump pocket infection that cultured positive for coagulase negative staphylococcus. Despite surgical exploration and drainage, IV Vancomycin therapy and daily irrigation with iodine solution, the abdominal pocket infection did not resolve and remained culture positive. Six months after implantation, she developed severe tachycardia and the HeartMate LVAD software indicated a sudden increase in device output. Therefore, the patient was referred to our center for heart transplantation consideration. Her PRA antibodies were found to be high and she had HLA antibodies, probably due to earlier massive transfusions and pregnancy. On admission, echocardiography showed a TCI Heartmate failure secondary to leaflet rupture and severe incompetence of inflow valve, with incomplete opening of aortic valve. After consultation with the Heartmate Support Staff, the device was switched from electromechanical to pneumatic setting, but there was no hemodynamic improvement. Therefore, the patient was placed on urgent list for heart transplantation. Before an acceptable donor became available, she developed progressive hemodynamic impairment, despite maximal IV inotropic support. She experienced two episodes of complete device blockage. Renal and hepatic functions started deteriorating. We therefore decided to replace the TCI Heartmate with a miniaturized and smaller DeBakey LVAD [1]. After dissection of extensive adhesions, with patient on cardiopulmonary bypass (CPB), the aorta cross-clamped and cardioplegic arrest induced. The TCI HeartMate was completely removed and replaced with a DeBakey device using the previous hole in the left ventricular apex for the inflow cannula of the new device. The aorta cross-clamp was then removed and with the heart beating, still on CPB, the DeBakey outflow graft was anastamosed to the previous ascending aorta site. The DeBakey ventricular assist devices (VAD) was de-aired, turned on, and the patient was weaned from CPB. After completion of all surgical procedure, the abdominal pocket of TCI HeartMate was drained and closed. A Gore-Tex sheet was wrapped around the device to prevent adhesions [2]. At the end of implantation, the patient was stable and the mechanical system working properly. The accurate position of left ventricular outflow cannula and adequate right ventricular function were confirmed by transesophageal echocardiogram. Inspection after removal confirmed the diagnosis of malfunction of the HeartMate LVAD: the inflow valvular bioprosthesis was incompetent because of valve degeneration: one of the leaflets was completely torn. The patient was returned to ICU in stable condition and had an uneventful postoperative course. Postoperatively, mean blood pressures were always >90 mmHg and the arterial pressure and flow waveforms showed a mild pulsate pattern. No right ventricle failure occurred. The urine output was normal, the SvO2 remained >70% and end organ dysfunction recovered quickly. The patient was extubated on the second postoperative day. Four days after implant, the patient was weaned from the inotropic support and four days later she was discharged from intensive care to medical ward. Our usual anticoagulation protocol was followed. After the first phase of intravenous heparin, we use a multisystematic anticoagulation protocol consisting of dipirydamole 1 g/day, penthoxifilline 800 mg/day, aspirin 100 mg/day, warfarin sodium (to maintain INR-International Normalized Ratio between 2.5 and 3.5), and low molecular weight heparin 2.000IU. Daily INR and PTT (thromboplastin time) samples were analyzed and weekly thrombelastograms were used to monitor coagulation trends. Finally, she was discharged home on the 30th postop day in stable condition. Afterward, the patient did very well: the device kept working properly and no complication occurred. The abdominal pocket healed completely without any evidence of further infection. The patient was very happy and confident with the device and she completed physical rehabilitation program. She received immunoglobulin and cyclofosfamide therapy in order to decrease the level of anti-HLA hyperimmunization. Vancomycin was given for other 5 weeks after implantation. Two months later, the patient, fully rehabilitated and in stable condition, was successfully transplanted and she was discharged home in good clinical status with no sign of acute rejection.
Although LVAD is widely accepted as an effective option in case of end-stage CHF, still cases of complications like infection or device dysfunction with mechanical failure are reported for various devices. The REMATCH study registered a probability of infection of 28% within 3 months after implantation and the probability of mechanical dysfunction of 35% at 24 months [3]. The rupture of the inflow valve in the TCI Heartmate has been already reported in several cases [4,5]. In this patient, we were forced to replace the device because of missing adequate donor and severe hemodynamic deterioration, despite intensive care. We preferred a smaller device because of the abdominal pocket infection. The DeBakey continuous flow LVAD was effective in replacing the previous pulsatile device and adequately supported the patient until transplantation, with good hemodynamic performance, good quality of life and no complications. We do believe that the DeBakey LVAD, in case of malfunction of other kind of device without right ventricular failure and no donor soon available, should be considered as a reliable replacement option. doi:10.1016/j.icvts.2004.06.001
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Abstract
1. Case report