Rachel Hards

Clinical Experience With HeartWare Left Ventricular Assist Device in Patients With End-Stage Heart Failure

BACKGROUND The gold standard treatment for end-stage heart failure is cardiac transplantation. Because of the increasing number of heart failure patients and the limited supply of donor hearts, a ventricular assist device (VAD) is used as a bridge to transplantation, recovery, or decision. Newer generation VADs have lower risk of fatal adverse events and are also smaller in size. We present our experience with the intrapericardial HeartWare VAD (HeartWare, Framingham, MA) and its clinical outcome. METHODS The clinical outcome of HeartWare VAD implantations for end-stage heart failure patients performed at Harefield Hospital from March 2007 to June 2011 was studied. The study design was a retrospective review of the prospectively collected data. RESULTS Thirty-four patients with a mean age of 51±10 years were included in this study. Twenty-nine patients were male (85%). The mean duration of mechanical support was 261±64 days. Five patients (15%) were successfully bridged to heart transplantation. The overall mortality was 24% (8 patients). There were 1 case of mechanical device failure (2%) and 3 cases of device failure due to thrombus formation (8%). Postoperative complications included 5 reoperations for bleeding (15%), 12 acute renal failures (36%), 7 respiratory failures (21%), 2 hepatic dysfunctions (6%), 3 neurologic dysfunctions (9%), 7 right-side heart failures (21%), and 5 driveline infections (15%). CONCLUSIONS Although cardiac transplantation remains the gold standard for treatment of end-stage heart failure patients, the HeartWare VAD can be used as a safe alternative with a satisfactory clinical outcome.

De Novo Aortic Regurgitation After Continuous-Flow Left Ventricular Assist Device Implantation

BACKGROUND Significant aortic regurgitation (AR) after continuous-flow left ventricular assist device (cf-LVAD) placement affects device performance and patient outcomes. This study examined the development of AR and long-term results after implantation of cf-LVADs. METHODS The study included all patients with no or less than mild AR who underwent HeartMate II (58 [62%]; Thoratec Corp, Pleasanton, CA) or HeartWare (35 [38%]; HeartWare International, Framingham, MA) implantation at our institute from July 2006 to July 2012. Serial echocardiograms were obtained preoperatively, at 1, 3 and 6 months postoperatively, and then at a minimum of 4-month intervals in patients with longer-term support. Kaplan-Meier estimates for freedom from moderate or greater AR were generated. Logistic regression analysis was used to define independent predictors of AR after cf-LVAD implantation. RESULTS Median duration of LVAD support was 527 days (25(th), 75(th): 289, 907; range, 60 to 2,433 days). Mild AR developed in 48 patients (51.6%) over a median duration of 126 days, with progression to moderate AR in 13 (14%) over 493 days and to severe AR in 2 (2.1%) over 1,231 days. The incidence of mild or greater AR was 43.1% in HeartMate II vs 65.7% in HeartWare recipients (p = 0.035). Overall freedom from moderate or greater AR was 94.7% ± 2.6% at 1 year, 86.9% ± 4.5% at 2 years, 82.8% ± 5.9% at 3 years, and 31% ± 16.9% at 4 years. Independent predictors of AR were duration of support (odds ratio, 1.002; 95% confidence interval, 1.000 to 1.004; p = 0.017) and a persistently closed aortic valve (odds ratio, 0.193; 95% confidence interval, 0.097 to 0.382; p < 0.001). CONCLUSIONS AR is associated with longer cf-LVAD support duration and persistent aortic valve closure. Incidence of moderate or greater AR after cf-LVAD implantation increases significantly after 3 years. The clinical implications of these data may warrant consideration of prophylactic aortic valve replacement at the time of cf-LVAD implantation, particularly with expected longer duration of support and in patients with preexisting AR that is more than mild.

Outcomes and Predictors of Early Mortality After Continuous-Flow Left Ventricular Assist Device Implantation as a Bridge to Transplantation

Left ventricular assist devices (LVADs) are fast becoming standard of care for patients with advanced heart failure. However, despite continuous improvement in VAD technology, there remains a significant early postoperative morbidity and mortality in this extreme patient group. The aim of the current study was to explore the short-term outcomes and predictors for 90 day mortality in the patients after implantation of continuous-flow LVAD. Perioperative clinical, echocardiographic, hemodynamic, and laboratory data of 90 day survivors and nonsurvivors were collected and compared retrospectively. Multivariate logistic regression analysis was performed on univariate predictors for 90 day mortality with an entry criterion of p < 0.1. Between July 2006 and May 2012, 117 patients underwent implantation of a continuous-flow LVAD as a bridge to transplantation: 71 (60.7%) HeartMate II (Thoratec Corp, Pleasanton, CA) and 46 (39.3%) HVAD (HeartWare International, Framingham, MA). All-cause 90 day mortality was 17.1%. Multivariate analysis revealed higher preoperative central venous pressure (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.014–1.378; p = 0.033) and higher age (OR, 1.14; 95% CI, 1.01–1.38; p = 0.045) as the only independent predictors for 90 day mortality. Optimization of preoperative volume status, preload, and right heart function as well as age-based selection of candidates for LVAD support are the critical factors influencing early outcome after continuous-flow LVAD implantation.

Minimally invasive access for off-pump HeartWare left ventricular assist device explantation

The implantation of a left ventricular assist device as a bridge to transplantation is a well-established treatment of end-stage heart failure in selected patients. Device-related infection is a well-known complication that may require the removal of the device. We describe a minimally invasive explantation approach with complete removal of all components of a HeartWare left ventricular assist device in a patient with persistent infection related to the device.

Does postoperative blood pressure influence development of aortic regurgitation following continuous-flow left ventricular assist device implantation?

OBJECTIVES The true impact of postoperative blood pressure (BP) control on development of aortic regurgitation (AR) following continuous-flow left ventricular assist device (CF-LVAD) implantation remains uncertain. This study examines the influence of BP in patients with de novo AR following CF-LVAD implantation. METHODS All patients with no or <mild AR who underwent CF-LVAD implantation from July 2006 to July 2012 at our institute and with subsequent device-support of ≥3months (n = 90) were studied. Serial echocardiograms and BP readings were obtained preoperatively, postoperatively at 1, 3 and 6 months, and then at a minimum of 4-monthly intervals. BP readings were compared between patients who developed mild AR (AR group) versus those who did not (non-AR group). Logistic regression analysis was used to define independent predictors of ≥mild AR following CF-LVAD implantation. RESULTS Median duration of CF-LVAD support was 575 days (range: 98-2433 days). Forty-eight patients (53.3%) developed mild AR over a median duration of 126 days. BP readings (median values, mmHg) between AR and non-AR groups showed statistically significant differences: at 3 months-systolic 99.5 vs 92.5 (P = 0.038), diastolic 81.5 vs 66 (P < 0.001), mean 86.5 vs 74 (P < 0.001) and at 6 months-diastolic 73 vs 62 (P = 0.044), mean 83 vs 74.5 (P = 0.049), respectively. Systolic BP at 3 months (P = 0.047, 95% CI 0.453-0.994, OR 0.671), aortic valve (AoV) closure (P = 0.01, 95% CI 0.002-0.429, OR 0.029) and duration of support (P = 0.04, 95% CI 1.000-1.009, OR 1.004) were found to be independent predictors of AR following CF-LVAD implantation. CONCLUSIONS BP readings at 3 months and 6 months showed a statistically significant association with ≥mild AR following CF-LVAD implantation, with systolic blood pressure at 3 months, aortic valve closure and longer support duration being independent predictors. Clinical implications of these data may warrant consideration of aggressive early control of BP to protect against the development/progress of AR following CF-LVAD implantation.

Preoperative predictors and outcomes of right ventricular assist device implantation after continuous-flow left ventricular assist device implantation

OBJECTIVE The outcomes of ventricular assist device therapy remain limited by right ventricular failure. We sought to define the predictors and evaluate the outcomes of right ventricular failure requiring right ventricular assist device support after long-term continuous-flow left ventricular assist device implantation. METHODS Records of all continuous-flow left ventricular assist device recipients for the last 10 years were analyzed, including patients on preoperative intra-aortic balloon pump, extracorporeal membrane oxygenation, and short-term ventricular assist device support. Perioperative clinical, echocardiographic, hemodynamic, and laboratory data of continuous-flow left ventricular assist device recipients requiring right ventricular assist device support (right ventricular assist device group) were compared with the rest of the patient cohort (control group). RESULTS Between July 2003 and June 2013, 152 patients underwent continuous-flow left ventricular assist device implantation as a bridge to transplantation. The overall postoperative incidence of right ventricular assist device support was 23.02% (n = 35). Right ventricular assist device implantation did not significantly affect eventual transplantation (P = .784) or longer-term survival (P = .870). Preoperative right ventricular diameter (P < .001), tricuspid annular plane systolic excursion (P < .001), previous sternotomy (P = .002), preoperative short-term mechanical support (P = .005), left atrial diameter (P = .014), female gender (P = .020), age (P = .027), and preoperative bilirubin levels (P = .031) were univariate predictors of right ventricular assist device implantation. Multivariate analysis revealed lesser tricuspid annular plane systolic excursion (P = .013; odds ratio, 0.613; 95% confidence interval, 0.417-0.901) and smaller left atrial diameter (P = .007; odds ratio, 0.818; 95% confidence interval, 0.707-0.947) as independent predictors of right ventricular assist device implantation. Receiver operating characteristic curve of tricuspid annular plane systolic excursion yielded an area under the curve of 0.85 (95% confidence interval, 0.781-0.923), with cutoff tricuspid annular plane systolic excursion less than 12.5 mm having 84% sensitivity and 75% specificity. CONCLUSIONS Lesser tricuspid annular plane systolic excursion and smaller left atrial diameter are independent predictors of the need for right ventricular assist device support after continuous-flow left ventricular assist device implantation. Right ventricular assist device implantation does not adversely affect eventual transplantation or survival after continuous-flow left ventricular assist device implantation.

Ventricular assist device outflow graft in congenitally corrected transposition of great arteries - a surgical challenge.

Congenitally corrected transposition of the great arteries is a complex congenital cardiac anomaly with a wide spectrum of morphologic features and clinical profiles. Most patients are diagnosed late in their life, undergoes surgical repairs, eventually leading to systemic ventricular failure needing heart transplant or mechanical circulatory assistance. As, aorta is located anterior to and left of the PA (Transposition of great arteries), the outflow graft of ventricular assist device traverse across pulmonary artery to reach aorta which poses challenge during further surgical explorations.

Outcomes in Patients Receiving HeartMate II Versus HVAD Left Ventricular Assist Device as a Bridge to Transplantation

OBJECTIVE Ventricular assist devices have become a standard treatment for patients with advanced heart failure. We present data comparing results after implantation of HeartMate II (HM II) versus HVAD (HW) left ventricular assist devices (LVADs) for the past 7 years at our institution. METHODS From July 2006 to August 2012, 121 consecutive patients underwent LVAD implantation: 70 (57.9%) received HM II and 51 (42.1%) HW. Patient demographics, perioperative characteristics, and laboratory parameters as well as postoperative outcome were compared retrospectively. RESULTS Patients in the HM II group were significantly younger (P < .01), with more deranged liver function (higher bilirubin [P = .02] and alanine aminotransferase [P = .01] levels), and had a significantly higher rate of preoperative infections requiring antibiotic treatment (P = .02) and a higher body core temperature (P < .01). Other demographic and preoperative parameters did not show statistical differences. Most postoperative characteristics were also similar between the two groups. HM II patients had a significantly higher transfusion rate, but there were no differences in incidence of resternotomy (P = .156). Recovery and VAD explantation were more likely in the HM II group (P = .02). Although there was no significant difference in survival (log rank test: P = .986; Breslow test: P = .827), HM II patients were more likely to develop a percutaneous site infection (P = .01). CONCLUSIONS Both HM II and HW provide similar early postoperative outcome and good long-term survival. The differences observed between the groups may be related to demographic and preoperative factors rather than the type of the device used.

Left ventricular assist device thrombosis due to clopidogrel resistance

A 53-year-old man presented with acute ST-elevation myocardial infarction and cardiogenic shock, due to proximal left main stem artery occlusion. Recovery was complicated by end-stage ischemic heart failure, and he was referred for left ventricular assist device (LVAD) implantation 2 months after his original presentation. A HeartMate II LVAD was implanted via a median sternotomy with cardiopulmonary bypass. He had an uneventful postoperative recovery and was started on clopidogrel and heparin infusion. Antithrombin 3 levels were in the normal range, and the activated partial thromboplastin time was 60–100 sec at all times. On postoperative day 9, he developed sudden severe hemodynamic compromise, and the LVAD stopped working. An emergency re-sternotomy showed that the LVAD was completely blocked by blood clots in the inflow and outflow cannulae (Figure 1). The LVAD was explanted and replaced with a CentriMag Levitronix system as a salvage operation. After 6 weeks, the CentriMag Levitronix system was replaced with a new HeartMate II LVAD, and the patient was started on heparin and aspirin. Later, heparin was changed to warfarin. The LVAD revealed diffuse thrombosis with no evidence of mechanical failure. Screening of the patient for clotting disorders and platelet dysfunction was remarkable for clopidogrel resistance.

Algorithms to guide ambulance clinicians in the management of emergencies in patients with implanted rotary left ventricular assist devices

Advances in left ventricular assist device (LVAD) therapy have resulted in increasing numbers of adult LVAD recipients in the community. However, device failure, stroke, bleeding, LVAD thrombosis and systemic infection can be life-threatening emergencies. Currently, four LVAD systems are implanted in six UK transplant centres, each of which provides device-specific information to local emergency services. This has resulted in inconsistent availability and content of information with the risks of delayed or inappropriate decision-making. In order to improve patient safety, a consortium of UK healthcare professionals with expertise in LVADs developed universally applicable prehospital emergency algorithms. Guidance was framed as closely as possible on the standard ABCDE approach to the assessment of critically ill patients.