HeartWare and HeartMate II left ventricular assist devices as bridge to transplantation: a comparative analysis

The impact of preoperative kidney replacement therapy on kidney outcome and survival in patients with left ventricular assist device

Left ventricular assist device (LVAD) has been highlighted as a new treatment option in the end-stage heart failure (HF). Kidney outcome after LVAD in severe cardiorenal syndrome (CRS) patients requiring kidney replacement therapy (KRT) is unclear. We investigated the impact of preoperative KRT on kidney function and survival in LVAD patients with severe CRS. A total of 50 patients followed up for at least 1 year after LVAD implantation was analyzed. The primary outcomes were estimated glomerular filtration rate and survival rate. Patients were divided into two groups depending on in-hospital KRT before LVAD implantation: the control group (n = 33) and the KRT group (n = 17). Postoperative KRT was performed for 76.5% of patients in the KRT group, and all of them discontinued KRT before discharge. There were no statistically significant differences in the degree of eGFR decline in survivors according to preoperative KRT. Although there were no statistically significant differences in the degree of eGFR decline in survivors regardless of preoperative KRT, old age (β -0.94, p < 0.01), preexisting chronic kidney disease (β -21.89, p < 0.01), and high serum creatinine (β -13.95, p < 0.01) were identified as independent predictors of post-LVAD eGFR decline. Mortality rate was higher, and more patients progressed to end-stage kidney disease in KRT group than control group. However, LVAD still can be considered as the treatment option in end-stage HF patients with severe CRS requiring KRT, especially in those with young age and previous normal kidney function.

Propensity Score-Matched Comparison of Right Ventricular Strain in Women and Men Before and After Left Ventricular Assist Device Implantation

Objective: Adverse events following left ventricular assist device (LVAD) implantation are more common in women than in men, but the impact of gender differences on right ventricular (RV) failure is not well defined. Therefore, we calculated RV strain before and after LVAD implantation in matched groups of men and women to determine if gender differences in RV failure after LVAD might account for the gender differences in overall outcomes. Methods: RV free wall longitudinal strain (FWS) and fractional area change were calculated preoperatively and 3 months postoperatively using speckle-tracking echocardiography analysis. A total of 172 patients (86 women, 86 men) were then propensity score matched (1:1) for comparison. Results: Although women had higher preoperative CHA₂DS₂-VASc scores and more frequent moderate mitral regurgitation than men (P = 0.018), the preoperative hemodynamic parameters were similar. Preoperative RV-FWS was -6.7% in women and -6.0% in men (P = 0.65). Postoperatively, women had more progression to severe tricuspid regurgitation (TR) than men (15% vs 7%, P = 0.06). At 3 months the RV-FWS was -7.7% in women and -7.0% in men (P = 0.59). Postoperative TR was moderate-severe in 20% of women and in 9% of men (P = 0.001). Women had a higher incidence of venous thromboembolism, cardiac arrhythmias, and bleeding compared with men. Women also had higher mortality rates at discharge and 30 days after surgery, but the survival rates at 5 years were similar. Conclusions: RV strain measurements track standard hemodynamic and echocardiographic parameters and confirm that gender differences in outcomes following LVAD implantation are not related to gender differences in RV failure rates.

Catheter Ablation of Ventricular Tachycardia in Patients With a Ventricular Assist Device: A Systematic Review of Procedural Characteristics and Outcomes

OBJECTIVES

This is a systematic review summarizing the procedural characteristics and outcomes of ventricular assist device (VAD)-related ventricular tachycardia (VT) ablation.

BACKGROUND

Drug-refractory VT refractory commonly develops post-VAD implantation. Procedural and outcome data come from small series or case reports.

METHODS

An electronic search was performed using major databases. Primary outcomes were VT recurrence, mortality, and cardiac transplantation. Secondary endpoints were acute procedural success and procedural complications.

RESULTS

Eighteen studies were included, with a total of 110 patients (mean age 59.6 ± 11 years, 89% men; VT storm 34%). Scar-related re-entry was the predominant mechanism of VT (90.3%) and cannula-related VT in 19.3% cases. Electroanatomical mapping interference occurred in 1.8% of cases; there were no reports of catheter entrapment. Noninducibility of clinical VT was achieved in 77.9%; procedural complications occurred in 9.4%. At a mean follow-up of 263.5 ± 267.0 days, VT recurred in 43.6%, 23.4% underwent cardiac transplant, and 48.1% died. There were no procedural-related deaths and no death was directly related to ventricular arrhythmia. In follow-up, there was a significant reduction in implantable cardioverter-defibrillator therapies or shocks (57.1% vs. 23.8%). Ablation allowed VT storm termination in 90% of patients.

CONCLUSIONS

VAD-related VT is predominantly related to pre-existing intrinsic myocardial scar rather than inflow cannula site insertion. Catheter ablation is a reasonable treatment strategy, albeit with expectedly high rate of recurrence, transplantation, and mortality related to severe underlying disease.

Longitudinal structural, functional, and cellular myocardial alterations with chronic centrifugal continuous-flow left ventricular assist device support

BACKGROUND

Left ventricular assist device (LVAD) support triggers adaptations within failing hearts. The HeartWare (HeartWare International, Inc., Framingham, MA) LVAD exhibits different flow profiles and afterload dependence compared with previous-generation devices, which may alter remodelling patterns. We sought to characterize myocardial adaptation to third-generation centrifugal-flow LVADs at a functional, hemodynamic, and structural level in addition to profiling transcriptomal changes using next-generation sequencing platforms.

METHODS

We studied 37 patients supported with the HeartWare device with paired measurements of invasive hemodynamics, serial longitudinal left ventricular (LV) and right ventricular (RV) 3-dimensional echocardiography, and N-terminal of the prohormone brain natriuretic peptide (NT-proBNP) measurements. Paired samples for comparison of histologic myocardial cellular size and transcriptomal profiling were performed on specimens taken at pump implant and transplantation.

RESULTS

The mean support duration was 280 ± 163 days. Mechanical unloading after HeartWare support resulted in reduced filling pressures (mean pulmonary capillary wedge pressure 27.1 ± 6.6 to 14.8 ± 5.1 mm Hg, p < 0.0001). Mean LV cardiomyocyte cell size decreased from 2,789.7 ± 671.8 to 2,290.8 ± 494.2 μm² (p = 0.02). LV and RV ejection fractions improved significantly (24% ± 8% to 35% ± 9% [p < 0.001] and 35% ± 11% to 40% ± 8% [p < 0.02], respectively). NT-proBNP levels fell 4.8-fold by Day 90 after support, consistent with a decrease in LV wall stress. Despite these concordant beneficial findings, the microRNA transcriptome did not change significantly across the group.

CONCLUSIONS

Reverse remodelling is evident at multiple levels with chronic HeartWare support in the absence of changes in the microRNA transcriptome. Successful myocardial unloading is associated with a decrease in wall stress, regression of cardiomyocyte hypertrophy, and an improvement in LV and RV ejection fractions.

HeartWare left ventricular assist device for the treatment of advanced heart failure

The importance of mechanical circulatory support in the therapy of advanced heart failure is steadily growing. The rapid developments in the field of mechanical support are characterized by continuous miniaturization and enhanced performance of the assist devices, providing increased pump durability and prolonged patient survival. The HeartWare left ventricular assist device system (HeartWare Inc., Framingham, MA, USA) is a mechanical ventricular assist device with over 8000 implantations worldwide. Compared with other available assist devices it is smaller in size and used in a broad range of patients. The possibility of minimally invasive procedures is one of the major benefits of the device – allowing implants and explants, as well as exchanges of the device with reduced surgical impact. We present here a review of the existing literature on the treatment of advanced heart failure using the HeartWare left ventricular assist device system.

Cardiac surgery 2014 reviewed

For the year 2014, more than 17,000 published references can be found in Pubmed when entering the search term "cardiac surgery". The last year has been characterized by a vivid discussion in the fields where classic cardiac surgery and modern interventional techniques overlap. Specifically, there have been important contributions in the field of coronary revascularization with either percutaneous coronary intervention or bypass surgery as well as in the fields of interventional valve therapy. Here, the US core valve trial with the first demonstration of a survival advantage at 1 year with transcatheter valves compared to surgical aortic valve replacement or the 5-year outcome of the SYNTAX trial with significant advantages for bypass surgery has been the landmark. However, in addition to these most visible publications, there have been several highly relevant and interesting contributions. This review article will summarize the most pertinent publications in the fields of coronary revascularization, surgical treatment of valve disease, heart failure (i.e., transplantation and ventricular assist devices) and aortic surgery. This condensed summary will provide the reader with "solid ground" for up-to-date decision-making in cardiac surgery.