Reduction in driveline infection rates: Results from the HeartMate II Multicenter Driveline Silicone Skin Interface (SSI) Registry.
BACKGROUND
During left ventricular assist device implantation, a surgical tunneling technique to keep the entire driveline (DL) velour portion in the subcutaneous tunnel, resulting in a silicone-skin interface (SSI) at the exit site, has been adopted by many centers. To assess long-term freedom from DL infection associated with this technique, a multicenter SSI registry was initiated. It was hypothesized that the modified tunneling technique is associated with at least 50% reduction in DL infection at 1 year post-implant compared with the velour-to-skin method used in the HeartMate II (HMII) Destination Therapy (DT) trial.


METHODS
SSI is a retrospective and prospective registry of patients who have received the HMII device. Results are reported from the retrospective cohort, which consists of 200 patients who were implanted during the period 2009-2012 with the SSI tunneling method and on HMII support for at least 10 months at the time of enrollment. The prevalence and incidence of DL infection after left ventricular assist device implantation in the SSI retrospective cohort were determined and compared with a control group of 201 patients also on HMII support for at least 10 months from the HMII DT clinical trial who were implanted during the period 2007-2009 using the traditional method in which a small section of the velour portion of the DL was externalized.


RESULTS
The 1-year and 2-year prevalence rates of DL infection were 9% and 19% in the SSI patient group compared with 23% and 35% in the control group (hazard ratio 0.49, 95% confidence interval 0.33-0.73, p < 0.001). The event-per-patient year was 0.11 and 0.22 for the SSI and control groups, respectively (p < 0.001). Based on a multivariate analysis, age and DL exit side were the only independent variables associated with DL infection. Effects of management changes over the eras were not studied and could have contributed to the findings.


CONCLUSIONS
These results suggest that leaving the entire DL velour portion below the skin is associated with 50% reduction in DL infection compared with results from the HMII DT trial.