N. Robinson-Smith

Four-year outcomes with third-generation centrifugal left ventricular assist devices in an era of restricted transplantation

OBJECTIVES Third-generation ventricular assist devices (VADs) are associated with improved outcomes, though in recent clinical trials bridge-to-transplant (BTT) rates are ∼30% at 6 months, so that transplantation can be used as a ‘bail out’ for serious complications. In the UK, there was a significant reduction in heart transplantation rates over the last decade, so that transplantation from VADs is much less frequent. The objective of this study was to determine outcomes and their predictors in this situation of low BTT rates, and as patients were exposed to long-term support, the incidence and outcomes of VAD thrombosis. METHODS We analysed outcomes for 102 consecutive patients between 2009 and 2013 (mean age 47 ± 13; VentrAssist n = 6 and HeartWare n = 96). The median duration of support was 462 ± 426 days. RESULTS Survival rates on the device were 75 and 66% at 1 and 2 years, respectively. Older age and more acute INTERMACS groups were significantly related to reduced survival within the first 90 days (P = 0.030 and 0.010, respectively). Poor preoperative right ventricular (RV) function had a negative effect on survival after 1 year (P = 0.009), though not earlier. VAD thrombosis (n = 24 HeartWare and n = 1 VentrAssist) occurred at 0.18 events per patient-year for HeartWare and 0.07 for VentrAssist devices at a median time of onset at 404 ± 281 days. There was no significant effect of VAD thrombosis on survival. Only 14 of 102 patients were transplanted at a median of 334 ± 347 days, and only 3 were transplanted within the first 6 months. CONCLUSIONS Third-generation left ventricular assist device implants with a low rate of transplantation have similar survival to destination therapy, and are susceptible to long-term complications of VAD thrombosis and right heart failure.

Development of de novo aortic valve incompetence in patients with the continuous-flow HeartWare ventricular assist device.

BACKGROUND In this study we investigated the development of aortic incompetence (AI) and change in aortic root and left ventricular dimensions after implantation of the continuous-flow HeartWare ventricular assist device (HVAD) in our adult patient cohort. METHODS A retrospective analysis of serial echocardiograms was performed on patients implanted with an HVAD between July 2009 and July 2013. Data from echocardiograms performed before and at 1 and 2 years (±3 months) were analyzed. Patients with native aortic valves (AoVs) with no previous intervention and HVAD in situ for ≥6 months were included. RESULTS A total of 73 HVADs in 71 patients with a mean duration of support of 624 ± 359 days were included in our study. One patient developed moderate AI at 1 year (1.9%). Mild or greater AI was more likely in those with a closed or intermittently opening AoV at 1 year (p = 0.005). Aortic annulus dimensions increased significantly at 1 and 2 years, regardless of extent of AI. At 2 years, in those with mild or worse AI, the sinuses of Valsalva were also larger (p = 0.002). Left ventricular end-diastolic dimension (LVEDD) was significantly reduced in those with no or trace AI at 1 and 2 years (p = 0.012 and p = 0.008, respectively), but remained unchanged in those with AI at both time-points. CONCLUSIONS The development of more than mild AI is rare in HVAD patients at our center. When encountered, it is more common with a closed AoV. Dilation of the aortic annulus, and root dilation in those with mild or more AI, is seen with HVAD support over time.

Impact of aortic valve closure on adverse events and outcomes with the HeartWare ventricular assist device

BACKGROUND This study examined whether aortic valve opening (AVO) and other echocardiographic parameters influence outcomes in patients on left ventricular (LV) assist device (LVAD) support. Pump thrombosis (PT) and ischemic stroke (IS) are known complications of LVAD, but mechanisms that could influence them are not completely understood. METHODS This was a retrospective analysis of 147 patients who received a HeartWare Ventricular Assist Device ( HeartWare International) as a bridge to transplant or to candidacy between July 2009 and August 2015, of whom 126 had at least 30 days of follow-up before the first event (30-days-out cohort). Outcomes included survival, PT, IS, and PT+IS (combined thrombotic event; CTE). RESULTS Median time on support was 518 days. Of the 30-days-out cohort, 29% had a first PT and 19% a first IS. AVO was associated with longer survival on device (1,081 vs 723 days; p = 0.01) in the entire cohort. In the 30-days-out cohort, the aortic valve was more frequently closed in patients with lower ejection fractions on support (14% ± 6% vs 18% ± 9%; p = 0.009), more dilated pre-event echocardiogram (LV end-diastolic diameter, 66 ± 12 mm vs 62 ± 10 mm; p = 0.04), and pre-implant LV end-diastolic diameter (70 ± 10 mm vs 66 ± 9 mm; p = 0.06). CTE-free survival on the device was lower with a closed aortic valve (897 vs 1,314 days; p = 0.003) as was PT-free survival on the device (1,070 vs 1,457 days; p = 0.02). Cox regression analysis showed that AVO was an independent predictor of CTE (p = 0.03) CONCLUSIONS: Thrombotic events are relatively frequent in patients on long-term LVAD support. A closed aortic valve was associated with decreased overall survival, thrombosis-free survival, and poorer LV function on support. These are high-risk patients, so whether they require more intense anti-coagulation or prioritizing for transplantation requires further research.

Myocardial Recovery Strategy with Decommissioning for the HeartWare Left Ventricular Assist Device

To manage myocardial recovery in patients with the HeartWare left ventricular assist device (HVAD), we describe a minimally invasive approach (decommissioning) that involves disconnecting the driveline and occluding the outflow tract through a small left thoracotomy incision, leaving the device in situ, in conjunction with optimal medical therapies and comprehensive assessment of left ventricular recovery. Nine patients (all male, 37 ± 12 years, all nonischemic dilated cardiomyopathy) had an HVAD implanted for 766 ± 343 days. When left ventricular function improved to mild impairment by echocardiography, patients underwent assessment at reduced flow (2578 ± 148 to 1822 ± 67 rpm) with documentation of compensated right heart hemodynamics and ejection fraction 52 ± 8%. Eight of nine patients underwent decommissioning, and 1 patient had a hybrid procedure of percutaneous occlusion of outflow graft and surgical division of driveline. Two patients died postoperatively at 413 days (sepsis) and 810 days (heart failure). In conclusion, in selected patients with nonischemic dilated cardiomyopathy, a prolonged period of HVAD support in conjunction with heart failure medications can lead to recovery of left ventricular function. Surgical decommissioning is then an option to remove these patients from support. These patients are, however, not cured and remain at risk for future deterioration in ventricular function and infections.