E. Dunn

Left Ventricular Assist Device Malfunctions: It Is More Than Just the Pump

Background: Reports of left ventricular assist device (LVAD) malfunction have focused on pump thrombosis. However, the device consists of the pump, driveline, and peripherals, all of which are potentially subject to failure. Methods: Prospectively collected data were reviewed for all LVAD device malfunctions (DMs) occurring in rotary LVADs implanted at a single center between April 2004 and May 2016. Durable LVADs included 108 Heartmate II (HM II) and 105 HeartWare VAD (HVAD). DM data were categorized according to device type and into categories related to the component that failed: (1) controller, (2) peripheral components, and (3) implantable blood pump or its integral electric driveline. Pump-related events were analyzed as pump-specific (suspected or confirmed thrombosis) or nonpump-specific (driveline failure). DM rates were reported as events per 1000 patient-days, and Cox proportional hazard models were used for time-to-event analyses. Cumulative rates of malfunction were examined for the main components of each type of LVAD. Results: Types of DM included controller failure (30%), battery failure (19%), or patient cable failure (14%), whereas only 13% were because of pump failure. DMs were more common in the HM II device (3.73 per 1000 patient-days versus 3.06 per 1000 patient-days for the HVAD, P<0.01). A higher rate of pump-specific malfunctions was discovered in those implanted with an HM II versus an HVAD (0.55 versus 0.39, respectively; P<0.01) and peripheral malfunctions (2.32 versus 1.78 for the HM II and HVAD, respectively; P<0.01); no difference occurred in the incidence of controller DM between the 2 LVADs. Patients with HVAD were 90% free of a pump-specific malfunction at 3 years compared with 56% for the HM II (log-rank P<0.003). Only 74% of the patients with HM II were free of pump thrombosis at 3 years compared with 90% of the patients with HVAD. Freedom from failure of the integrated driveline was 79% at 3 years for the HM II but 100% for the HVAD (log-rank P<0.02). Conclusions: Device malfunction is much broader than pump failure alone and occurs for different components at different rates based on the type of LVAD.

Substantial Reduction in Driveline Infection Rates With the Modification of Driveline Dressing Protocol

BACKGROUND Driveline infection (DLI) is a cause of morbidity and mortality in patients with continuous-flow left ventricular assist devices (CF-LVADs). We hypothesized that an alternate dressing protocol would decrease the rate of DLIs. METHODS AND RESULTS A retrospective review of CF-LVAD implants at a single institution from January 2010 to October 2015 was conducted. Patients were divided into implants before (group 1) and after (group 2) the introduction of the new protocol on September 1, 2012. Patients were followed until death, transplantation, change in dressing type, or 2 years. 153 patients were included: 61 in group 1 and 92 in group 2. Group 1 had fewer HVADs than group 2 (27.9% vs 71.7%; P < .001) and more destination therapy, although the latter was not statistically significant (50.8% vs 34.8%; P = .118). At 24 months, the freedom from DLI was 53% in group 1 and 89% in group 2 (P = .01). Group 1 had a significantly greater risk of DLI than group 2 (incident rate ratio 3.18, 95% confidence interval 1.23-8.18; P = .016). CONCLUSIONS Dramatic improvement in freedom from DLI at 2 years was achieved with a new driveline dressing protocol. This demonstrates that DLI rates can be improved with alternate percutaneous site care techniques in CF-LVAD patients.