Abstract 11343: Aortic Valve Opening Predicts Thrombotic Events during Continuous Flow Left Ventricular Assist Device (CF-LVAD) Support
Background: Managing CF-LVADs to promote intermittent Aortic Valve Opening (AVO) has been proposed to limit adverse events; however, the safety of this strategy has not been investigated. We explored the association between AVO and thrombotic events (pump thrombosis and thromboembolic events) during CF-LVAD support.
Methods: A retrospective review of 81 consecutive patients who underwent Heart Mate (HM) II CF-LVAD placement at our center was conducted. Baseline demographics, AVO, LVAD speed and flows were compared between thrombotic and non-thrombotic groups. AVO was ascertained from all clinical echocardiograms performed during LVAD support and scored as: 0=no opening, 1=intermittent opening, 2=opening every beat. In the thrombotic group, data was acquired until thrombotic event (TE). Pump thrombosis was confirmed by CT scan of the outflow graft or through direct visualization during device exchange.
Results: During CF-LVAD support, 13/81(16%) of patients had a TE. The median time to TE after LVAD placement was 70 days (range: 1-733). All patients were on aspirin and warfarin (therapeutic range: 1.5-2.5). Nearest to TE, INR was 1.61±0.54 and 4 patients were subtherapuetic. Of the 13 patients with TE, 7 had CVA’s, 1 presented with a coronary artery embolus and 5 had pump thrombosis. Five of the thirteen patients with TE had active infection ≤2 weeks prior to TE. Higher AVO score was associated with an increased likelihood of TE (OR: 2.74, 95% CI: 1.10-6.89) and patients with a TE tended to be maintained on lower LVAD speeds, p=0.10 (Table 1). No difference in HM II flows was seen between groups; however, this data was limited by dropout at low flows.
Conclusion: TE’s were more likely in patients with more frequent AVO, who were maintained on lower LVAD speeds. Our data raises the concern that reduced flow through the pump might predispose patients to TE. Further investigation will define the risk benefit profile of adjusting speed to sustain AVO during CF-LVAD support.
- © 2012 by American Heart Association, Inc.