Background
We evaluated thrombotic and bleeding outcomes in patients with continuous flow left ventricular assist devices (CF-LVADs), stratified by anticoagulation intensity. Previous studies of outpatients with CF-LVADs have suggested that target international normalized ratio (INR) values less than 2.5 (range 2-3) may be used. However, recent studies reported an increase in pump thrombosis among CF-LVADs, especially within the first 6 months of implant.
Methods and Results
We retrospectively reviewed 249 outpatients at our center who received a CF-LVAD between 1/2005 and 8/2013. Using Poisson models we analyzed their 10,927 INRs to determine INR-specific rates of thrombotic (ischemic stroke and suspected pump thrombosis) and hemorrhagic (gastrointestinal bleeding and hemorrhagic stroke) events occurring outside of the hospital. In multivariate analyses, we adjusted for age, sex, atrial fibrillation, coronary disease, and LVAD type as time-dependent Cox proportional hazard models. During a mean follow-up of 17.6 ± 13.6 months, thrombotic events occurred in 46 outpatients. The highest event rate (0.40 thrombotic events per patient-year) was in the INR range of < 1.5, but INR values of 1.5-1.99 also had high rates (0.16 thrombotic events per patient-year). INR was inversely associated with thrombotic events (HR 0.40, 95% 0.22-0.72; P = 0.002). The optimal INR based on weighted mortality of thrombotic and bleeding events was 2.6.
Conclusions
INR is inversely related to thrombotic events occurring outside of the hospital among patients supported with CF-LVADs. INR values less than 2.0 increase the rate of thrombotic events occurring outside of the hospital among patients supported with CF-LVADs.
Background
Stroke is a significant complication in patients supported with continuous-flow left ventricular assist devices (CF-LVAD) and hypertension (HTN) is a significant risk factor for stroke, but the association between blood pressure and stroke in LVAD patients is not well characterized.
Methods
We identified 275 consecutive patients who survived implant hospitalization between 1/2005 and 4/2013. Patients were divided into above and below median SBP (100 mmHg) groups based on their averaged systolic blood pressure (SBP) during the last 48 hours prior to discharge from implantation hospitalization. The groups were compared for the primary outcome of time-to-stroke.
Results
The above-median SBP (AM-SBP) group had mean SBP=110 mmHg and the below-median SBP (BM-SBP) group had mean SBP=95 mmHg. There were no significant between-group differences in BMI, smoking, vascular disease, HTN, atrial fibrillation, or prior stroke. During a mean follow-up of 16 months, stroke occurred in 16% of the AM-SBP group vs. 7% of the BM-SBP group, HR 2.38 (95% CI 1.11 - 5.11), with a similar proportion of hemorrhagic and ischemic strokes in each group. In Cox proportional hazard models adjusting for age, diabetes, or prior stroke, the HR remained statistically significant. SBP as a continuous variable predictor of stroke had an AUC of 0.64 in an ROC analysis.
Conclusion
In this large, CF-LVAD cohort, elevated SBP was independently associated with a greater risk of subsequent stroke. These results identify management of HTN as a potential modifiable risk factor for reducing the incidence of stroke in patients supported by CF-LVAD.
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