Impact of time off anticoagulation in patients with continuous-flow left ventricular assist devices.

Patients with left ventricular assist devices (LVADs) receive anticoagulation to decrease the risk of thrombosis. Various circumstances require discontinuing anticoagulation in LVAD patients, but the risks entailed are not well defined. In a retrospective review of LVAD implantation procedures, we examined the effect of time off anticoagulation on thrombosis and mortality rates after implantation. An international normalized ratio ≤ 1.5 was used to screen for patients taken off anticoagulation. Patients were divided into three groups by the cumulative number of days off anticoagulation: no discontinuation, short-term discontinuation (< 30 days), and long-term discontinuation (≥ 30 days). Rates of ischemic stroke, pump thrombosis, and mortality were compared among groups. Of 245 patients who underwent LVAD implantation during the study, 70 (28.6%) were off anticoagulation during follow-up: 37 (15.1%) had short-term discontinuation (median, 11 days), and 33 (13.5%) had long-term discontinuation (median, 124 days). Patients with long-term discontinuation had a higher rate of ischemic stroke (adjusted hazard ratio 8.5, p = 0.001) and death (adjusted hazard ratio 3.9, p = 0.001). The three groups did not differ in pump thrombosis rate. We conclude that after LVAD implantation, discontinuing anticoagulation for ≥ 30 days is independently associated with an increased risk of ischemic stroke and death.

Extracorporeal Membrane Oxygenation for COVID-19: Collaborative Experience From the Texas Medical Center in Houston With 2 Years Follow-Up.

Patients with severe refractory hypoxemic respiratory failure may benefit from extracorporeal membrane oxygenation (ECMO) for salvage therapy. The Coronavirus disease 2019 (COVID-19) pandemic offered three high-volume independent ECMO programs at a large medical center the chance to collaborate to optimize ECMO care at the beginning of the pandemic in Spring 2020. Between March 15, 2020, and May 30, 2020, 3,615 inpatients with COVID-19 were treated at the Texas Medical Center. During this time, 35 COVID-19 patients were cannulated for ECMO, all but one in a veno-venous configuration. At hospital discharge, 23 (66%) of the 35 patients were alive. Twelve patients died of vasodilatory shock (n = 9), intracranial hemorrhage (n = 2), and cannulation-related bleeding and multiorgan dysfunction (n = 1). The average duration of ECMO was 13.6 days in survivors and 25.0 days in nonsurvivors ( p < 0.04). At 1 year follow-up, all 23 discharged patients were still alive, making the 1 year survival rate 66% (23/35). At 2 years follow-up, the overall rate of survival was 63% (22/35). Of those patients who survived 2 years, all were at home and alive and well at follow-up.

First-in-Human Study of the Saranas Early Bird Bleed Monitoring System for the Detection of Endovascular Procedure-Related Bleeding Events.

OBJECTIVES: To evaluate the safety and accuracy of the Early Bird Bleed Monitoring System (EBBMS; Saranas) for the detection of access-site related bleeds in humans undergoing endovascular procedures. BACKGROUND: Bleeding complications after endovascular procedures are frequent and associated with poor prognosis. The EBBMS is a novel technology designed to detect in real time the onset, progression, and severity of internal bleeds. METHODS: The EBBMS was used during and after endovascular procedures, either as a venous or arterial access sheath. The primary endpoint was the level of agreement in bleed detection between the Saranas EBBMS and postprocedural computed tomography. RESULTS: From August 2018 to December 2018, a total of 60 patients from five United States sites were enrolled and underwent elective endovascular procedures (transcatheter aortic valve replacement [67%], percutaneous coronary intervention [13%], percutaneous ventricular assist device [8%], balloon aortic valvuloplasty [7%], transcatheter mitral valve repair/replacement [4%], and endovascular aneurysmal repair [2%]). The EBBMS detected the absence of bleeds in 21 patients (35%) and bleeds in 39 patients (65%), with bleeding severity level 1 in 20 patients (33%), level 2 in 15 patients (25%), and level 3 in 4 patients (7%). Bleeding detection occurred during the procedure in 31% of patients and post procedure in 69% of patients. The level of agreement between the EBBMS and computed tomography scan was high (Cohen's kappa=0.84). No device-related complications were reported. CONCLUSIONS: The EBBMS was safe across a variety of endovascular procedures and detected bleeding events with a high level of agreement with postprocedural computed tomography scan.

Factor Xa inhibitors in patients with continuous-flow left ventricular assist devices.

OBJECTIVE: Warfarin is standard anticoagulation therapy for patients with a continuous-flow left ventricular assist device (CF-LVAD). However, warfarin requires regular monitoring and dosage adjustments and fails for many patients, causing thromboembolic and bleeding events. Factor Xa inhibitors have been shown to be noninferior to warfarin in preventing strokes and are associated with less intracranial hemorrhage in patients with atrial fibrillation. We evaluated treatment safety and effectiveness in CF-LVAD patients who switched from warfarin to a factor Xa inhibitor (apixaban or rivaroxaban) after warfarin failure. METHODS: This was a retrospective, single-center study of patients treated between 2008 and 2018. We assessed the occurrence of stroke, non-central nervous system (CNS) embolism, pump thrombosis, and major gastrointestinal bleeding and intracranial hemorrhage during therapy. RESULTS: We identified seven patients: five were male, the average body mass index was 30 kg/m2, and average age was 56 years. Preimplantation comorbidities included hypertension (all patients) and diabetes mellitus, ischemic cardiomyopathy, atrial fibrillation, and previous myocardial infarction (four patients each). Overall, patients received warfarin for 3968 days and apixaban/rivaroxaban for 1459 days. The warfarin group was within the therapeutic INR range (2.0-3.0) 30% of the time. Complication rates did not differ between warfarin and apixaban/rivaroxaban: strokes, 0.20 vs none, non-CNS embolism, 0.54 vs none; pump thrombosis, 0.27 vs none; major gastrointestinal bleeding, 0.20 vs 0.50; intracranial hemorrhage, 0.13 vs none. CONCLUSIONS: Factor Xa inhibitors may be viable treatment options for CF-LVAD patients for whom warfarin therapy has failed. Large prospective studies are necessary to confirm these results.

A coronary cameral fistula treated with coil embolization.

A 56-year-old man who had twice previously undergone orthotopic heart transplantation was admitted with dyspnea and heart failure symptoms. A biopsy excluded rejection. Left heart catheterization revealed a coronary cameral fistula. After the patient was given mild diuretics, his condition improved. No significant fistula flow was detected, and he was discharged. Several months later, the patient was readmitted with worsening chest pain and dyspnea. Left ventricular end-diastolic pressure and flow through the fistula were increased. To correct the coronary cameral fistula, we performed a coil embolization without complications. Several months later at follow-up, the patient's symptoms had resolved, and his left ventricular end-diastolic pressure had normalized. We conclude that coronary fistulas may be caused by trauma to the heart during the de-airing process, which may be prevented in the future with the development of safer and more effective de-airing techniques.

Acute kidney injury after implantation of a left ventricular assist device: a comparison of axial-flow (HeartMate II) and centrifugal-flow (HeartWare HVAD) devices.

Continuous-flow left ventricular assist devices (CF-LVADs) are increasingly being used to treat advanced, refractory chronic heart failure. Herein, we sought to determine the incidence of postoperative acute kidney injury (AKI) in axial-flow (HeartMate II; HM-II) and centrifugal-flow (HVAD) CF-LVAD recipients, as well as the effect of AKI on mortality. The study cohort comprised 520 patients who received a HM-II (n = 398) or HVAD (n = 122) at our center between November 2003 and March 2016. Their records were reviewed to determine the incidence of RIFLE-defined AKI after LVAD implantation. We compared the perioperative characteristics, postoperative complications, and survival rates of the patients with and without AKI and differentiated the outcomes based on device type (HM-II or HVAD). Seventy-five patients (14.4%) developed AKI postoperatively. Patients with AKI after LVAD implantation had significantly reduced survival compared to patients without AKI (p = 0.01). Cox proportional hazards models showed that AKI was a significant independent predictor of mortality (HR = 1.54, p = 0.03). Preoperative mechanical circulatory support and prolonged cardiopulmonary bypass time were independent predictors of AKI. The incidence of AKI was similar for HM-II and HVAD recipients (p = 0.25). There was no significant difference in AKI rates for the HM-II and HVAD recipients. Developing AKI adversely affected survival.

Association between cell-derived microparticles and adverse events in patients with nonpulsatile left ventricular assist devices.

BACKGROUND: Continuous-flow left ventricular assist devices (LVADs) expose blood cells to high shear stress, potentially resulting in the production of microparticles that express phosphatidylserine (PS+) and promote coagulation and inflammation. In this prospective study, we attempted to determine whether PS+ microparticle levels correlate with clinical outcomes in LVAD-supported patients. METHODS: We enrolled 20 patients undergoing implantation of the HeartMate II LVAD (Thoratec Corp, Pleasanton, CA) and 10 healthy controls who provided reference values for the microparticle assays. Plasma was collected before LVAD implantation, at discharge, at the 3-month follow-up, and when an adverse clinical event occurred. We quantified PS+ microparticles in the plasma using flow cytometry. RESULTS: During the study period, 8 patients developed adverse clinical events: ventricular tachycardia storm in 1, non-ST-elevation myocardial infarction in 2, arterial thrombosis in 2, gastrointestinal bleeding in 2, and stroke in 3. Levels of PS+ microparticles were higher in patients at baseline than in healthy controls (2.11% ± 1.26% vs 0.69% ± 0.46%, p = 0.007). After LVAD implantation, patient PS+ microparticle levels increased to 2.39% ± 1.22% at discharge and then leveled to 1.97% ± 1.25% at the 3-month follow-up. Importantly, levels of PS+ microparticles were significantly higher in patients who developed an adverse event than in patients with no events (3.82% ± 1.17% vs 1.57% ± 0.59%, p < 0.001), even though the 2 patient groups did not markedly differ in other clinical and hematologic parameters. CONCLUSIONS: Our results suggest that an elevation of PS+ microparticle levels may be associated with adverse clinical events. Thus, measuring PS+ microparticle levels in LVAD-supported patients may help identify patients at increased risk for adverse events.

Improved hemodynamics with a novel miniaturized intra-aortic axial flow pump in a porcine model of acute left ventricular dysfunction.

Currently, long-term mechanical circulatory support (MCS) is limited to large, complex devices that require invasive, high-risk surgical implantation. These devices are mainly used in patients with late stage heart failure (HF). We are developing a novel percutaneous intra-aortic micro-axial fluid entrainment pump intended for long-term MCS in patients with earlier stage HF. This study examined the pump's hemodynamic effects in a porcine model of acute HF. In three porcine experiments, the pump was deployed in the thoracic aorta by standard cardiac catheterization techniques and was anchored with self-expanding struts. Acute cardiac dysfunction was induced by infusing esmolol continuously. Pump support increased cardiac output (+10.4%), stroke volume (+8.9%), and ejection fraction (+10.8%) while decreasing cardiac stroke work (-10.8%) and afterload (-22.7%). Furthermore, pump support significantly enhanced renal perfusion through sustained increases in both renal artery flow (+36.4%) and pressure (+73.6%). In a porcine model of acute HF, the catheter-based intra-aortic fluid entrainment pump improved hemodynamics and renal perfusion. These results suggest that the pump could improve HF outcomes and patients' quality of life by resting the heart, promoting reverse remodeling, and augmenting end-organ perfusion. Furthermore, the enhanced renal perfusion may help disrupt the cardiorenal syndrome cycle and improve HF treatment.

Remission of chronic anthracycline-induced heart failure with support from a continuous-flow left ventricular assist device.

We report the case of a patient who had chronic anthracycline-induced cardiomyopathy that was reversed after treatment with a left ventricular assist device. A 29-year-old woman had undergone anthracycline-based chemotherapy as a teenager in 1991 and 1992 and received a diagnosis of dilated cardiomyopathy 10 years later. Optimal medical therapy had initially controlled the symptoms of heart failure. However, in June 2006, the symptoms worsened to New York Heart Association functional class IV status. We implanted a continuous-flow left ventricular assist device as a bridge to cardiac transplantation; of note, a left ventricular core biopsy at that time showed no replacement fibrosis. The patient's clinical status improved thereafter, enabling left ventricular assist device ex-plantation after 17 months. To our knowledge, this is the first report of the use of left ventricular assist device support to reverse chronic anthracycline-induced heart failure.