J.W. Haft

Gastrointestinal bleeding and subsequent risk of thromboembolic events during support with a left ventricular assist device

BACKGROUND Modern left ventricular assist devices (LVAD) require anti-coagulation (AC) with warfarin and anti-platelet therapy to prevent thromboembolic complications in patients. Gastrointestinal bleeding (GI) is a significant adverse event in these patients and treatment typically requires reduction or elimination of AC or anti-platelet therapy. It is not known whether alterations in AC to treat GI bleeding influence subsequent risk of thromboembolic (TE) events during LVAD support. METHODS Between July 2003 and September 2011, 389 patients (308 male) underwent implantation of a continuous-flow LVAD at the University of Michigan Health System and the Mayo Clinic. Median age at implant was 60 years (range 18 to 79 years). Outcomes were analyzed for the association of GI bleeding events and subsequent TE events, defined as stroke, transient ischemic attack, hemolysis or suspected or confirmed pump thrombosis. RESULTS Median survival was 10 months (maximum 7.2 years, total 439 patient-years). TE events occurring within the first 30 days were not counted. Overall survival and freedom from an outcome event were assessed using the Kaplan-Meier method. Associations between GI bleeding and subsequent TE events and survival impact were analyzed as time-dependent covariates. One hundred ninety-nine GI bleeding episodes occurred in 116 of 389 patients (30%) for an event rate of 0.45 GI bleed/patient-year of support. One hundred thirty-eight TE events occurred in 97 of 389 patients (25%) for an event rate of 0.31 TE event/patient-year of support. Median time from LVAD implant to first GI bleed was 5 months (range 1 to 116 months) and to first TE event was 6 months (range 1 to 29 months). For patients who had a TE event after GI bleed, the median interval was 5 months (range 0.5 to 25 months). TE events were 7.4-fold more likely in patients who had a prior GI bleed (range 4.9- to 11.1-fold) (p < 0.001); however, neither the presence of GI bleeding (0.7 to 1.2) nor a TE event (0.8 to 2.0) portended a lower overall survival. CONCLUSIONS Patients who had GI bleeding were at significantly higher risk for a subsequent TE event. Although the exact cause of this relationship is unknown, it suggests that a reduction in anti-coagulation and anti-platelet management to treat GI bleeds may contribute to this risk.

Device exchange after primary left ventricular assist device implantation: Indications and outcomes

BACKGROUND Patients are being supported for longer periods with implantable left ventricular assist devices (LVADs) owing to longer transplantation wait times and approval of LVADs for destination therapy. This comes with an increased potential need for device exchange when complications arise. There are few data examining this patient population. METHODS Between August 1998 and January 2012, 45 patients (34 men) underwent 57 device exchanges after primary pulsatile or continuous-flow LVAD implantation. The median age at the initial LVAD implantation was 58 years (range, 28-78 years) and the median time to first device exchange was 15 months (range, immediate-56 months). Indications for primary LVAD included bridge to transplantation in all but 10 patients, and devices included the HeartMate I (Thoratec, Pleasanton, CA) in 16 patients, the HeartMate II (Thoratec) in 21 patients, the HeartWare HVAD (HeartWare, Framingham, MA) in 2 patients, the DuraHeart I (Terumo Heart, Ann Arbor, MI) in 1 patient, and other devices in 5 patients. Indications for reoperation included device/component failure (n=24), major driveline infection (n=15), pump thrombus (n=15), and other indications (n=2). RESULTS Pumps implanted in 57 reoperations included the HeartMate I in 15 patients, the HeartMate II in 35 patients, the HeartWare HVAD in 2 patients, the DuraHeart I in 2 patients, and other devices in 3 patients. Early mortality occurred in 2/57 (3.5%) patients. Median follow-up was 18 months (range, 1-113 months); median length of LVAD therapy after the first device exchange was 13 months (range, 1-59 months). Actuarial 1-year survival and freedom from repeated device exchange after the first exchange was 89% and 79%, respectively. CONCLUSIONS Device exchange may be required after LVAD implantation. This can be performed with low early mortality and no adverse effect on late survival. Multiple reoperations may be required in some patients.

Delayed sternal closure does not increase late infection risk in patients undergoing left ventricular assist device implantation

BACKGROUND Delayed sternal closure (DSC) is employed after conventional cardiac surgery without a significantly increased risk of late mediastinitis or sternal wound infection. There are no data specifically examining its late effects on patients undergoing implantation with a ventricular assist device (VAD). METHODS Between October 1996 and October 2010, 364 patients underwent primary VAD implant and DSC was utilized in 184 (51%) patients for coagulopathy (n = 155; 84%), hemodynamic instability (n = 103; 56%), isolated right ventricular dysfunction (n = 15; 8%) or unspecified reasons (n = 17; 9%). RESULTS Median duration of DSC was 1 day (range 1 to 7 days). Patients with DSC were older (54.5 vs. 50.3 years, p = 0.002), had a higher incidence of previous sternotomy (42% vs. 28%, p = 0.005), pre-operative intra-aortic balloon pump (50% vs. 30%, p < 0.001), pre-operative temporary extracorporeal mechanical circulatory support (23% vs 10%, p < 0.001), lower platelet counts (171,000 vs. 209,000, p < 0.001) and lower hematocrit levels (32% vs. 36%, p < 0.001). Operative (11% vs. 9%, p = 0.65) or late (2 years; 66 ± 7% vs 66 ± 7%, p = 0.720) mortality; composite incidence of mediastinitis, percutaneous drive-line infection, pocket infection and VAD-related endocarditis (15% vs. 16%, p = 0.79); re-exploration for bleeding (18% vs. 18%, p = 0.99); urgent transplantation for infection (4% vs. 3%, p = 0.99); or need for device exchange (9% vs. 10%, p = 0.16) was not increased after DSC when compared with immediate sternal closure. DSC increased ICU stay (10 vs. 5 days, p = 0.001). CONCLUSIONS DSC was performed most commonly for coagulopathy and/or hemodynamic instability, and patients were older with a greater severity of illness as shown by the higher incidence of right-sided circulatory failure and history of prior sternotomy. Although DSC was associated with longer ICU stay, DSC was not associated with a significantly increased risk of death or infection.