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Evaluation of Anticoagulation Bridging Strategies in LVAD Patients
Abstracts 171 Effect of Anesthesia on Cardiac Hemodynamics in patients undergoing durable LVAD Implantation: The EACH LVAD Study T.C. Hanff,1 P.A. Patel,2 K.L. Kurcik,1 S. Rao,1 S.E. Kimmel,3 M.E. Putt,3 P. Atluri,4 C.A. Bermudez,4 M.A. Acker,4 E.Y. Birati,1 J.E. Rame,1 and J.W. Wald.1 1Division of Cardiology, University of Pennsylvania, Philadelphia, PA; 2Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA; 3Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA; and the 4 Division of Cardiovascular Surgery, University of Pennsylvania, Philadelphia, PA. Purpose: Right ventricular (RV) dysfunction is often unmasked or exacerbated during implantation of a left ventricular assist device (LVAD). Prior to LVAD implantation, the effect of anesthesia induction on RV performance is unknown. We assessed for early hemodynamic changes in the RV after induction, prior to initiation of cardiopulmonary bypass (CPB), in the presence or absence of preoperative temporary mechanical circulatory support (tMCS). Methods: We prospectively collected hemodynamic measurements in patients undergoing LVAD implantation at a large academic institution between 9/2017 and 9/2018. Preoperative RV hemodynamics were compared to RV hemodynamics post-induction and intubation but prior to CPB, including central venous pressure (CVP), mean pulmonary artery pressure (mPAP), and pulmonary artery pulsatility index (PAPi). Serial hemodynamics and vasoactive inotropic score (VIS) were analyzed over time using random effects models, adjusting for induction agents and use of pre-operative tMCS. Results: There were 41 patients included in this analysis, with 4 intubated prior to induction. There was a significant increase in CVP (3.6 mmHg, p<0.001) and mPAP (4.0 mmHg, p<0.001) and decrease in PAPi (-1.5, p<0.001) at all time points in the first hour after induction. PAPi was worse at all times among patients receiving preoperative tMCS (-2.83, p<0.001), but had smaller decline from baseline (Figure 1). Recipients of intra-aortic balloon pumps were 14 of 17 tMCS cases and had similar reduction in PAPi at all time points (-2.5, p<0.001), with insufficient counts of temporary LVADs or VA ECMO for individual analysis. Changes in PAPi were not associated with choice of anesthetic, baseline VIS, or change in VIS. Conclusion: RV hemodynamics acutely worsen after anesthesia induction prior to bypass initiation in LVAD recipients. Patients with preoperative tMCS have worse RV hemodynamics at each timepoint but less significant decline over time.
172 Evaluation of Anticoagulation Bridging Strategies in LVAD Patients A.D. Rabon,1 D.J. Taber,2 W.E. Uber,1 B.A. Houston,3 and H. Meadows.1 1Department of Pharmacy Services, Medical University of South Carolina, Charleston, SC; 2Department of Surgery, Medical University of South Carolina, Charleston, SC; and the 3Division of Cardiology, Medical University of South Carolina, Charleston, SC. Purpose: Warfarin is the established anticoagulant for LVAD patients. For patients with a subtherapeutic INR, bridging with low molecular weight heparin (LMWH) or unfractionated heparin (UFH) is common, but safety and efficacy of these strategies have not been established.
S79 Methods: We performed a retrospective longitudinal cohort study to evaluate safety and efficacy of bridging strategies including all adult LVAD patients implanted at the Medical University of South Carolina from 8/ 2014 to 7/2017. Patients were followed from LVAD implantation to transplant, death, or study termination. Bridging episodes occurred when a patient received LMWH or UFH; non-bridging episodes were defined as any time period a patient did not receive LMWH or UFH for a subtherapeutic INR. Primary outcomes were major bleeding and thrombotic events evaluated for each bridging or non-bridging episode in an intention to treat analysis. Multivariable Cox regression survival models were used for analysis. Results: There were 563 episodes evaluated in 50 patients (182 bridging episodes and 381 non-bridging episodes). Of the 182 bridging episodes, 129 were with LMWH (70.9%) and 53 (29.1%) with UFH. Overall, the median INR (IQR) was 1.8 (1.5-2.1) at bridging and was similar between all bridging episode types. Compared to non-bridging episodes, UFH (HR 3.75, [95%CI 1.45-9.73], P = 0.007) and LMWH (HR 2.25, [1.03-4.94], P = 0.04) were both associated with an increased risk of bleeding. There was a trend toward reduced bleeding risk when comparing LMWH to UFH (HR 0.4, [0.13-1.19], P = 0.1). Among bridging episodes, all 17 thrombotic events occurred in the LMWH group and were primarily pump thrombosis events. Compared to non-bridging events, LMWH was not associated with a decreased risk of clotting events (HR 1.56, [0.28-8.73], P = 0.62). Patients with an INR ≤ 1.5 at the time of bridging had a trend towards increased risk of thrombotic events (HR 2.43, [0.88-6.69], P = 0.09). For patients with an INR ≥ 2.0 at the time of bridging, a significant increase in bleeding events was observed (HR 2.34, [1.06-5.14], P = 0.03). Conclusion: Our data suggests that bridging is not necessary for certain patients with a subtherapeutic INR and that the efficacy particularly of LMWH bridging in LVAD patients warrants further investigation. Furthermore, INR at time of bridging may significantly affect subsequent risk of bleeding and clotting. 173 Concentrated Factor Administration and Subsequent Pump Thrombosis on HeartMate II LVAD Support H. Shah,1 R. Cogswell,1 J. Misialek,2 J. Schultz,1 A. Nitzkowski,3 R. John,4 C. Martin,1 M. Pritzker,1 and A. Shaffer.4 1Cardiology, University of Minnesota, Minneapolis, MN; 2Epidemiology & Community Health, University of Minnesota, Minneapolis, MN; 3Pharmacology, University of Minnesota, Minneapolis, MN; and the 4Cardiothoracic Surgery, University of Minnesota, Minneapolis, MN. Purpose: Limited data exists regarding concentrated factor administration during continuous flow left ventricular assist device (CF-LVAD) implantation and subsequent rates of pump thrombosis. While the hemocompatability profile of CF pumps are presently changing, this is the largest concentrated factor experience reported in CF-LVAD patients to date. Methods: Patients with first time HeartMate II implantation (n=328) were identified from a single center continuous-flow (CF-LVAD) database (n=400). Patients were coded as receiving concentrated factor if prothrombin 4 factor complex or recombinant factor VIIa was charted intra-operatively or within 48 hours of device implantation. Laboratory and hospitalization data were reviewed to determine time to first suspected or confirmed pump thrombosis. Suspected pump thrombosis was defined as a sustained rise in lactate dehydrogenase (LDH) > 2.5 the upper limit of normal. Confirmed pump thrombosis was defined as a pump exchange, cardiac transplant, or death associated with a hemolysis event. Multivariable cox regression was utilized to determine the association between concentrated factor administration and the time to suspected or confirmed pump thrombosis. Results: Eighteen percent of patients (59/328) received concentrated factor intra-operatively or within 48 hours of device implantation. On multivariate analysis, concentrated factor administration was not significantly associated with time to first suspected pump thrombosis (HR 1.17, 95 % CI 0.62-2.20, p = 0.62) or confirmed pump thrombosis (HR 1.19, 95 % CI 0.43-3.3, p = 0.73). All models were adjusted for discharge pump speed, age, bridge to transplant status, diabetes, and INTERMACS profile. Conclusion: While no statistical association was observed between concentrated factor administration and subsequent pump thrombosis in this
172 Evaluation of Anticoagulation Bridging Strategies in LVAD Patients A.D. Rabon,1 D.J. Taber,2 W.E. Uber,1 B.A. Houston,3 and H. Meadows.1 1Department of Pharmacy Services, Medical University of South Carolina, Charleston, SC; 2Department of Surgery, Medical University of South Carolina, Charleston, SC; and the 3Division of Cardiology, Medical University of South Carolina, Charleston, SC. Purpose: Warfarin is the established anticoagulant for LVAD patients. For patients with a subtherapeutic INR, bridging with low molecular weight heparin (LMWH) or unfractionated heparin (UFH) is common, but safety and efficacy of these strategies have not been established.
S79 Methods: We performed a retrospective longitudinal cohort study to evaluate safety and efficacy of bridging strategies including all adult LVAD patients implanted at the Medical University of South Carolina from 8/ 2014 to 7/2017. Patients were followed from LVAD implantation to transplant, death, or study termination. Bridging episodes occurred when a patient received LMWH or UFH; non-bridging episodes were defined as any time period a patient did not receive LMWH or UFH for a subtherapeutic INR. Primary outcomes were major bleeding and thrombotic events evaluated for each bridging or non-bridging episode in an intention to treat analysis. Multivariable Cox regression survival models were used for analysis. Results: There were 563 episodes evaluated in 50 patients (182 bridging episodes and 381 non-bridging episodes). Of the 182 bridging episodes, 129 were with LMWH (70.9%) and 53 (29.1%) with UFH. Overall, the median INR (IQR) was 1.8 (1.5-2.1) at bridging and was similar between all bridging episode types. Compared to non-bridging episodes, UFH (HR 3.75, [95%CI 1.45-9.73], P = 0.007) and LMWH (HR 2.25, [1.03-4.94], P = 0.04) were both associated with an increased risk of bleeding. There was a trend toward reduced bleeding risk when comparing LMWH to UFH (HR 0.4, [0.13-1.19], P = 0.1). Among bridging episodes, all 17 thrombotic events occurred in the LMWH group and were primarily pump thrombosis events. Compared to non-bridging events, LMWH was not associated with a decreased risk of clotting events (HR 1.56, [0.28-8.73], P = 0.62). Patients with an INR ≤ 1.5 at the time of bridging had a trend towards increased risk of thrombotic events (HR 2.43, [0.88-6.69], P = 0.09). For patients with an INR ≥ 2.0 at the time of bridging, a significant increase in bleeding events was observed (HR 2.34, [1.06-5.14], P = 0.03). Conclusion: Our data suggests that bridging is not necessary for certain patients with a subtherapeutic INR and that the efficacy particularly of LMWH bridging in LVAD patients warrants further investigation. Furthermore, INR at time of bridging may significantly affect subsequent risk of bleeding and clotting. 173 Concentrated Factor Administration and Subsequent Pump Thrombosis on HeartMate II LVAD Support H. Shah,1 R. Cogswell,1 J. Misialek,2 J. Schultz,1 A. Nitzkowski,3 R. John,4 C. Martin,1 M. Pritzker,1 and A. Shaffer.4 1Cardiology, University of Minnesota, Minneapolis, MN; 2Epidemiology & Community Health, University of Minnesota, Minneapolis, MN; 3Pharmacology, University of Minnesota, Minneapolis, MN; and the 4Cardiothoracic Surgery, University of Minnesota, Minneapolis, MN. Purpose: Limited data exists regarding concentrated factor administration during continuous flow left ventricular assist device (CF-LVAD) implantation and subsequent rates of pump thrombosis. While the hemocompatability profile of CF pumps are presently changing, this is the largest concentrated factor experience reported in CF-LVAD patients to date. Methods: Patients with first time HeartMate II implantation (n=328) were identified from a single center continuous-flow (CF-LVAD) database (n=400). Patients were coded as receiving concentrated factor if prothrombin 4 factor complex or recombinant factor VIIa was charted intra-operatively or within 48 hours of device implantation. Laboratory and hospitalization data were reviewed to determine time to first suspected or confirmed pump thrombosis. Suspected pump thrombosis was defined as a sustained rise in lactate dehydrogenase (LDH) > 2.5 the upper limit of normal. Confirmed pump thrombosis was defined as a pump exchange, cardiac transplant, or death associated with a hemolysis event. Multivariable cox regression was utilized to determine the association between concentrated factor administration and the time to suspected or confirmed pump thrombosis. Results: Eighteen percent of patients (59/328) received concentrated factor intra-operatively or within 48 hours of device implantation. On multivariate analysis, concentrated factor administration was not significantly associated with time to first suspected pump thrombosis (HR 1.17, 95 % CI 0.62-2.20, p = 0.62) or confirmed pump thrombosis (HR 1.19, 95 % CI 0.43-3.3, p = 0.73). All models were adjusted for discharge pump speed, age, bridge to transplant status, diabetes, and INTERMACS profile. Conclusion: While no statistical association was observed between concentrated factor administration and subsequent pump thrombosis in this