Faculty Bibliography

BACKGROUND:Anticoagulation with warfarin is common prior to heart transplantation and complicates perioperative management. METHODS:This single-center, non-interventional, retrospective cohort study evaluated heart transplants before and after institution of a PCC-based preoperative warfarin reversal protocol for heart transplantation. Patients with international normalized ratio (INR) > 1.5 received who PCC prior to heart transplant surgery were compared to a control group prior to implementation of a PCC protocol. Co-primary endpoints were utilization of individual blood products. Secondary endpoints included in-hospital mortality, reoperation for bleeding, delayed sternal closure, thromboembolic events, duration of chest tube use, time to extubation, ICU length of stay, and hospital length of stay. RESULTS:The study included 106 consecutive heart transplant patients (PCC cohort = 57, historical control cohort = 49). There was a significant reduction in FFP utilization in the PCC cohort (6 units vs 8 units, p=0.002). Rates of PRBC and platelet transfusion were similar between groups. There was a significant increase in the incidence of cryoprecipitate utilization in the PCC cohort, which can likely be attributed to decreased antifibrinolytic utilization. There were no differences in secondary endpoints between groups, including thromboembolic events. CONCLUSIONS:This study found that a PCC-based warfarin reversal protocol significantly reduced FFP utilization compared to historical controls without impacting other clinically important surgical outcomes. These data suggest that PCC is a valuable tool for INR normalization that could safely reduce FFP administration and offer a practical alternative to traditional approaches for INR reversal prior to heart transplantation.

BACKGROUND:Little data exists regarding reversal and resumption of antithrombotics following left ventricular assist device (LVAD)-associated intracranial hemorrhage (ICH). METHODS:Prospectively collected data of LVAD patients with ICH was reviewed. Coagulopathy reversal agents, antithrombotic regimens and thrombotic (venous thromboembolism, ischemic stroke, myocardial infarction) and hemorrhagic (recurrent ICH, gastrointestinal bleed, anemia requiring transfusion) complications were recorded. RESULTS:Of 405 patients, intracranial hemorrhage occurred in 39 (10%): 23 intracerebral hemorrhages, 10 subarachnoid hemorrhages, and 6 subdural hematomas. Of 27 patients who received antithrombotic reversal, 8 (30%) had inadequate coagulopathy reversal and 3 of these had hemorrhage expansion or died before repeat imaging. One (4%) had a thrombotic complication (deep vein thrombosis). Antithrombotic therapy was resumed in 17(100%) survivors in a median time 8 days for antiplatelet agents, and 14 days for warfarin. Recurrent intracranial hemorrhage occurred within a median of 7 days of antithrombotic resumption, while ischemic stroke occurred in a median of 428 days. Patients who resumed antiplatelets alone (N=4) had a trend toward more thrombotic events (1.37 vs. 0.14 events-per-patient-year [EPPY],P=0.08), including more fatal thrombotic events (0.34 EPPY vs. 0.08, P=0.89) compared to those resuming warfarin±antiplatelet (N=14). Non-fatal hemorrhage event rates were 0.34 EPPY in the warfarin±antiplatelet vs. 0 EPPY in the antiplatelet alone group (P=0.16). No fatal hemorrhagic events occurred. CONCLUSIONS:Reversal of anticoagulation appears safe following LVAD-associated intracranial hemorrhage, though inadequate reversal was common. Resumption of warfarin±antiplatelet was associated with fewer fatal and non-fatal thrombotic events compared to antiplatelets alone, though more non-fatal hemorrhage events occurred.

BACKGROUND:Infection has been associated with stroke in patients with left ventricular assist devices (LVAD); however, little data exist on the timing, type and mortality impact of infection-related stroke. METHODS:Prospectively collected data of HeartMate II (N = 332) and HeartWare (N = 70) LVAD patients from a single center were reviewed. Only strokes (ischemic or hemorrhagic) that occurred within 6 weeks following a LVAD infection were considered in analyses. The association between LVAD infections (wound, pump pocket, driveline and/or bloodstream infection [BSI]), specific pathogens and ischemic and hemorrhagic strokes was evaluated using multivariable logistic regression analysis. The impact of infection-related stroke on cumulative survival was assessed using Kaplan-Meier analysis. RESULTS:Of 402 patients, LVAD infection occurred in 158 (39%) including BSI in 107 (27%), driveline infection in 67 (17%), wound infection in 31 (8%) and pump pocket infection in 24 (6%). LVAD infection-related stroke occurred in 20/158 (13%) patients in a median of 4 days (0-36 days) from documented infection. In multivariable analysis, ischemic stroke was associated with wound infection (aOR 9.0, 95% CI 2.4-34.0, P = 0.001) and BSI (aOR 7.7, 95% CI 0.9-66.0, P = 0.064), and hemorrhagic stroke was associated with BSI in 100% of cases (P = 0.01). There was no association with driveline or pump pocket infection. The cumulative survival rate among patients with infection-related stroke was significantly lower compared to those with LVAD infection but no stroke (log-rank P < 0.001). There was a trend toward shorter stroke-free survival among patients with LVAD infection. CONCLUSIONS:LVAD infections, particularly BSI, are significantly associated with stroke, and infection-related stroke conferred significantly lower cumulative survival.

Control of mechanical circulatory support pump output typically requires that pressure-regulating functions be accomplished by active control of the speed or geometry of the device, with feedback from pressure or flow sensors. This article presents a different design approach, with a pressure-regulating device as the core design feature, allowing the essential control function of regulating pressure to be directly programmed into the hydromechanical design. We show the step-by-step transformation of a pressure-regulating device into a continuous-flow total artificial heart that passively balances left and right circulations without the need for pressure and flow sensors. In addition, we discuss a ventricular assist device that prevents backflow in the event of power interruption and also dynamically interacts with residual ventricle function to preserve pulsatility.

Anemia is common in patients with mechanical circulatory support and is associated with increased morbidity. Repletion using parenteral iron infusions has been proven to be beneficial in patients with heart failure. In this report, we describe a case of increased power and flows of continuous-flow left ventricular assist device (LVAD) during an iron dextran infusion. We subsequently studied the effects of iron dextran infusion in an in vitro LVAD mock circulatory loop. The observed increase in flow and power was most likely due to drug-patient interaction rather than drug-LVAD interaction. Mock loops and in vivo animal models may be necessary for proactive evaluation of the safety of intravenous (IV) preparations in this patient population.

Introduction: Cardiogenic shock is associated with high in-hospital mortality rates regardless of etiology. Recently, there has been an increase in utilization of acute mechanical circulatory support (MCS) in patients with cardiogenic shock. Although there is no consensus as to the most appropriate device for any particular patient presentation, acute MCS devices have been widely adopted in institutions that favor an aggressive approach to cardiogenic shock. Establishment of an Adult ECMO Program at our institution has led to experience with additional acute MCS devices. The complexity of these clinical situations led to the creation of a multidisciplinary team, including a combination of cardiologists, surgeons, interventionalists, and intensivists, committed to treating these patients. As an early ECMO Program and Cardiogenic Shock Team, we sought to review our early experience with acute MCS for cardiogenic shock to define our baseline strategies and outcomes in this patient population. Materials and Methods: We completed a retrospective review of cardiogenic shock patients who were treated with acute MCS by Fiscal Year (September 1 to August 31) beginning with Fiscal Year (FY) 2014. We reviewed implant volume by device, including temporary surgical ventricular assist device (VAD), percutaneous and surgical Impella, percutaneous RVADs, and veno-arterial Extracorporeal Membrane Oxygenation (VA-ECMO). Data collected included etiology of shock, indication for device implantation, type of support offered, length of support, and outcome of support. For each category of device, we also reviewed our outcomes by mirroring the established ELSO benchmarks of "Survival from ECMO" and "Survival to Discharge." Results: We found a steady increase in the use of acute MCS for treatment of cardiogenic shock from FY 2014 to FY 2018. From FY 2014 to 2015 there was an increase from zero to 18 implants. The following year (FY 2016) revealed a 100% increase, with a total of 36 implants. The volume increased more slowly (16%/year) the following two years (FY 2017, FY 2018) with 43 and 48 implants, respectively. Overall outcome assessment revealed that 68% of patients survived acute MCS and 53% of patients survived to hospital discharge with an increased survival to discharge in the last fiscal year to 62%. Conclusion: Creation of an Adult ECMO Program and a multidisciplinary Cardiogenic Shock Team correlated with an increase in the number of patients supported with acute MCS. As the team gains experience with these patients and the devices available to support them, we expect the outcomes to continue to improve. Patient selection, surgical approaches and techniques, standardizing medical therapy, and managing and reducing complications will give these patients the best opportunity to survive