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Initial clinical experience with a novel left ventricular assist device with a magnetically levitated rotor in a multi-institutional trial

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Background

Third-generation rotary blood pumps have magnetically levitated rotors that eliminate mechanical wear over the years. Together with their potential for miniaturization, these pumps seem suitable for long-term support of patients with a wide range of body surface areas (BSA). Recently, the novel HVAD pump (HeartWare Inc, Framingham, MA), a miniaturized centrifugal pump with a hydrodynamic, magnetically levitated rotor, became ready for clinical application.

Methods

In a multi-institutional trial in Europe and Australia, 23 patients (mean age, 47.9 ± 12 years) in end-stage heart failure were enrolled in 5 centers. The primary end point of the bridge-to-transplant study was survival to heart transplant or survival to 180 days on the device, whichever occurred first. Follow-up data at 1 year are presented. The small size of the device allows for intrapericardial placement of the pump.

Results

Implant procedures were generally fast and uneventful. Mean duration of support was 167 ± 143 days (range, 13–425 days), and mean blood flow provided by the pump was 6.1 ± 1.1 liters/min. At the 180-day end point, 2 patients had undergone successful transplant at 157 and 175 days, 2 patients died while on the device, and 19 patients continued pump support for more than 180 days. Actuarial survival after 6 months was 91% and was 86% at the 1-year follow-up.

Conclusions

The design of the HVAD pump enables a quick and less invasive implantation. The results to date demonstrate satisfactory long-term survival with excellent quality of life in this cohort of 23 patients of the initial multi-institutional Conformité Européene (CE) mark trial.

Section snippets

HVAD pump

The HVAD pump is a miniaturized centrifugal blood pump with a displaced volume of only 50 ml, a maximum external diameter of 53 mm, and a weight of 140 grams (Figure 1). A short inflow cannula integrated into the pump housing is placed in the apex of the left ventricle, and a 10-mm pre-clotted vascular graft connects as an outflow conduit from the pump to the ascending aorta. This configuration allows intrapericardial placement, thereby avoiding abdominal surgery and pump pockets. A thin and

Device implantation and anticoagulation

Device implantation was performed through a standard sternotomy using normothermic cardiopulmonary bypass (CPB) with beating heart.5 The sewing ring was attached epicardially to the left ventricular (LV) apex, and the inflow cannula was inserted through the sewing ring into the LV. The outflow graft was cut to length and sewn to the ascending aorta using an end-to-side anastomosis. The percutaneous lead was tunneled to exit in the right upper quadrant. After de-airing was completed, the clamp

Results

Between March 2006 and December 2007, 20 men and 3 women with a mean age of 48 ± 12.6 years (range, 25–68 years) who met the study entry criteria were enrolled into the clinical evaluation trial of the HVAD pump. Baseline hemodynamic data are provided in Table 1, and pre-operative risk factors are listed in Table 2. Body surface areas varied widely, with a mean of 1.98 m2 (range, 1.5–2.6 m2), and the mean body mass index was 27.6 kg/m2 (range, 20.2–40.8 kg/m2). Idiopathic cardiomyopathy was the

Adverse events

The most common AE within a 1-year follow-up period was infection, which occurred on 16 occasions in 11 patients (Table 4). Sepsis developed in 3 patients (1 fungal, 2 bacterial). None of the septic episodes were related to the device. Eight local driveline exit site infections developed in 6 patients. The exit site infections appeared rather late, between 102 and 364 days (mean, 238 days) post-operatively. With the exception of 1 surgical débridement, all of the exit sites were successfully

Discussion

In November 1998, when the first miniaturized axial-flow pumps were implanted in humans,7 no one could have anticipated that the evolving technology of rotary blood pumps would replace the displacement pumps used for the previous 20 years. Rotary pumps seemed to provide striking advantages in terms of potential for miniaturization of pumps and controller units, elimination of noise, reduction of driveline diameters, and the need for compliance chambers. However, there was uncertainty regarding

Disclosure statement

G. M. Wieselthaler is member of the Medical Advisory Board of HeartWare Inc, and his institution participates in technical research that is funded by a grant from HeartWare Inc. None of the other authors has a financial relationship with a commercial entity that has an interest in the subject of the presented manuscript or other conflicts of interest to disclose.

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