Ventricular Assist Devices - Evolution of Surgical Heart Failure Treatment

Recent Developments in Ventricular Assist Device Therapy

The evolution of left ventricular assist devices (LVADs) from large, pulsatile systems to compact, continuous-flow pumps has significantly improved implantation outcomes and patient mobility. Minimally invasive surgical techniques have emerged that offer reduced morbidity and enhanced recovery for LVAD recipients. Innovations in wireless power transfer technologies aim to mitigate driveline-related complications, enhancing patient safety and quality of life. Pediatric ventricular assist devices (VADs) remain a critical unmet need; challenges in developing pediatric VADs include device sizing and managing congenital heart disease. Advances in LVAD technology adapted for use in right ventricular assist devices (RVADs) make possible the effective management of right ventricular failure in patients with acute cardiac conditions or congenital heart defects. To address disparities in mechanical circulatory support (MCS) access, cost-effective VAD designs have been developed internationally. The Vitalmex device from Mexico City combines pulsatile-flow technology with a paracorporeal design, utilizing cost-effective materials like silicone-elastic and titanium, and features a reusable pump housing to minimize manufacturing and operational costs. Romanian researchers have used advanced mathematical modeling and three-dimensional (3D) printing to produce a rim-driven, hubless axial-flow pump, achieving efficient blood flow with a compact design that includes a wireless power supply to reduce infection risk. In conclusion, MCS continues to advance with technological innovation and global collaboration. Ongoing efforts are essential to optimize outcomes, expand indications, and improve access to life-saving therapies worldwide.

Minimally invasive versus conventional continuous-flow left ventricular assist device implantation for heart failure: a meta-analysis

Many studies have reported various minimally invasive techniques for continuous-flow left ventricular assist device implantation. There is no consensus on whether minimally invasive techniques can bring more benefits for patients compared with the conventional technique, due to the limited number of patients and diverse results in current studies. Our meta-analysis mainly discussed the comparison of minimally invasive and conventional techniques. We searched controlled trials from PubMed, Cochrane Library, and Embase databases until Dec 11, 2020. Perioperative and postoperative outcomes were analyzed among 10 included studies. The protocol has been registered with PROSPERO (CRD42020221532). There were no statistical differences in the 30-day mortality (OR 0.57; 95% CI 0.29 to 1.14), 6-month mortality (OR 0.66; 95% CI 0.41 to 1.05), neurological dysfunction (OR 1.10; 95% CI 0.69 to 1.76), major infection (OR 0.68; 95% CI 0.36 to 1.28), and pump thrombus (OR 1.49; 95% CI 0.63 to 3.52) among the cohorts. Minimally invasive techniques were associated with lower incidences of major bleeding (OR 0.39; 95% CI 0.22 to 0.68), severe right heart failure (OR 0.43; 95% CI 0.23 to 0.81), and less blood-product utilization (SMD -0.44). Sensitivity analysis suggested that minimally invasive techniques were associated with a lower incidence of respiratory failure (OR 0.50; 95% CI 0.26 to 0.96) and shorter mechanical ventilation time (SMD -0.53). Subgroup analysis demonstrated that patients, implanted with a centrifugal pump by minimally invasive techniques, were associated with a shorter length of intensive care unit (ICU) stay (SMD -0.27) and hospital stay (SMD -0.42), and less blood-product utilization (SMD -0.26). In conclusion, minimally invasive techniques can reduce the risks of major bleeding, severe right heart failure, and blood-product utilization, as well as have positive impacts on reducing mechanical ventilation time and the risk of respiratory failure. Minimally invasive centrifugal pump implantation can reduce the length of ICU and hospital stay.

Durable Continuous-Flow Mechanical Circulatory Support: State of the Art

Implantable mechanical circulatory support (MCS) systems for ventricular assist device (VAD) therapy have emerged as an important strategy due to a shortage of donor organs for heart transplantation. A growing number of patients are receiving permanent assist devices, while fewer are undergoing heart transplantation (Htx). Continuous-flow (CF) pumps, as devices that can be permanently implanted, show promise for the treatment of both young and old patients with heart failure (HF). Further improvement of these devices will decrease adverse events, enable pulse modulation of continuous blood flow, and improve automatic remote monitoring. Ease of use for patients could also be improved. We herein report on the current state of the art regarding implantable CF pumps for use as MCS systems in the treatment of advanced refractory HF.

Low immunogenic endothelial cells endothelialize the Left Ventricular Assist Device

Low haemocompatibility of left ventricular assist devices (LVAD) surfaces necessitates anticoagulative therapy. Endothelial cell (EC) seeding can support haemocompatibility, however, the availability of autologous ECs is limited. In contrast, allogeneic ECs are readily available in sufficient quantity, but HLA disparities induce harmful immune responses causing EC loss. In this study, we investigated the feasibility of using allogeneic low immunogenic ECs to endothelialize LVAD sintered inflow cannulas (SIC). To reduce the immunogenicity of ECs, we applied an inducible lentiviral vector to deliver short-hairpins RNA to silence HLA class I expression. HLA class I expression on ECs was conditionally silenced by up to 70%. Sufficient and comparable endothelialization rates were achieved with HLA-expressing or HLA-silenced ECs. Cell proliferation was not impaired by cell-to-Sintered Inflow Cannulas (SIC) contact or by silencing HLA expression. The levels of endothelial phenotypic and thrombogenic markers or cytokine secretion profiles remained unaffected. HLA-silenced ECs-coated SIC exhibited reduced thrombogenicity. In contrast to native ECs, HLA-silenced ECs showed lower cell lysis rates when exposed to allogeneic T cells or specific anti-HLA antibodies. Allogeneic HLA-silenced ECs could potentially become a valuable source for LVAD endothelialization to reduce immunogenicity and correspondingly the need for anticoagulative therapy which can entail severe side effects.