Faculty Bibliography

Right ventricular failure is a difficult problem to manage and typically carries a dismal prognosis. In the setting of post-left ventricular assist device implantation (LVAD), right ventricular dysfunction both in the early and late stages is of particularly high incidence and concern. There are currently no agreed upon preoperative algorithms to predict patients at risk for this problem, thus adding another level of complexity to treatment. Furthermore, there is no current technology available for chronic right ventricular support and the devices currently in use are LVADS modified to adapt to the right circulatory system. This review provides an overview of right ventricular failure, particularly after LVAD implantation, and describes the survival outcomes and continued challenges in this area.

BACKGROUND: Drive-line infections (DLIs) frequently complicate ventricular assist device (VAD) support. We sought to describe the detailed effects of DLIs over time in patients with continuous-flow VADs, including the onset, risk factors, organisms involved, association with invasive infections, and outcomes. METHODS: We reviewed data for patients with HeartMate II VADs (HMII) who were implanted at the Cleveland Clinic from October 2004 to September 2011 and followed through December 2011. DLIs were defined according to published criteria. RESULTS: DLIs developed in 45 of 194 HMII VADs over a median period of 232 days (range 22 to 883 days). Hazard for DLI was 2.0%/month, but transiently peaked at 11%/month at 7.5 months after implant. Pseudomonas aeruginosa accounted for 31%, 42% and 55% of initial, final and deep DLIs, respectively. Of the 40 superficial DLIs, 13 (32.5%) became deep. DLI-associated bacteremia and hospitalization occurred in 14 of 45 (31%) and 30 of 45 (67%), respectively. All patients received antibiotics (median 171 days), but only 3 of 44 (6.8%) developed an antibiotic complication. DLIs increased the risk for death while on VAD support (HR 2.20, 95% CI 1.20 to 4.05; p = 0.01). Six and 12 months after DLI, mortality was 9.8% and 31%, but the competing event of transplantation occurred successfully in 20% and 28%, respectively. CONCLUSIONS: Most DLIs begin superficially with peak hazard at 7.5 months after implant. Depth of infection and infecting organism may evolve over months on support, with Pseudomonas becoming more prominent. Although effectively managed for prolonged periods, DLIs are associated with reduced survival on VAD support. Earlier transplantation is the most successful approach to treatment.

Patients on peripheral extracorporeal membrane oxygenation (ECMO) are at risk for lower extremity ischemia. Effective monitoring is needed to identify complications quickly and allow timely correction. Near-infrared spectroscopy has been used extensively in cerebral monitoring during cardiac surgery. We present its use in monitoring lower extremity perfusion in patients on ECMO. Five patients on ECMO had near-infrared spectroscopy monitors placed on the calf of both lower extremities. Continuous real-time tissue oxygen saturation data (stO2) was displayed and recorded. Two patients had lower extremity complications in the leg with the arterial cannula. The patients with complications had lower stO2 in the cannulated leg at the time of ECMO insertion, larger differences in stO2 between the legs at the time of insertion, lower nadir stO2s, and larger peak differences in stO2 between the legs than patients without limb complications. The use of near-infrared spectroscopy for continuous monitoring of tissue oxygenation in the lower extremities in patients on ECMO may allow early identification of patients with lower extremity complications.

Number of left ventricular assist device (LVAD) implantations increases every year, particularly LVADs for destination therapy (DT). Right ventricular failure (RVF) has been recognized as a serious complication of LVAD implantation. Reported incidence of RVF after LVAD ranges from 6% to 44%, varying mostly due to differences in RVF definition, different types of LVADs, and differences in patient populations included in studies. RVF complicating LVAD implantation is associated with worse postoperative mortality and morbidity including worse end-organ function, longer hospital length of stay, and lower success of bridge to transplant (BTT) therapy. Importance of RVF and its predictors in a setting of LVAD implantation has been recognized early, as evidenced by abundant number of attempts to identify independent risk factors and develop RVF predictor scores with a common purpose to improve patient selection and outcomes by recognizing potential need for biventricular assist device (BiVAD) at the time of LVAD implantation. The aim of this article is to review and summarize current body of knowledge on risk factors and prediction scores of RVF after LVAD implantation. Despite abundance of studies and proposed risk scores for RVF following LVAD, certain common limitations make their implementation and clinical usefulness questionable. Regardless, value of these studies lies in providing information on potential key predictors for RVF that can be taken into account in clinical decision making. Further investigation of current predictors and existing scores as well as new studies involving larger patient populations and more sophisticated statistical prediction models are necessary. Additionally, a short description of our empirical institutional approach to management of RVF following LVAD implantation is provided.