Stopping LVAD Bleeding: A Piece of the Puzzle

Reduced Rate of Anemia after Transcatheter Aortic Valve Replacement

Background/Objectives: We sought to evaluate changes in hemoglobin level and renal function in patients 5-12 months after transcatheter aortic valve replacement (TAVR), and to examine possible relationships between these changes. Anemia is common in older people with severe aortic stenosis (AS). The two most common etiologies for anemia in this population are iron deficiency due to gastrointestinal blood loss and renal failure. Angiodysplasia in the gastrointestinal system is a feature of AS syndrome. Methods: We collected clinical data, including hemoglobin level and renal function before and 5-12 months after TAVR in 315 consecutive patients. To examine whether calculated clinical predictors such as EuroScore 2 are associated with the persistence of anemia after TAVR, we performed multivariable correlation analysis with post-TAVR anemia as the dependent variable. Results: The mean hemoglobin level increased significantly (from 11.76 to 12.16 g/dL, p < 0.0001) 5-12 months after TAVR, and the number of patients with anemia decreased significantly (from 67.5% to 53.9%, p < 0.0001). At 5-12 months following TAVR, a small reduction in estimated glomerular filtration rate was observed (from 60.05 ± 24.1 to 58.30 ± 24.50 mL/min, p = 0.024). The multivariable correlation analysis did not identify clinical predictors of persistent anemia. Conclusions: A significant increase in hemoglobin was observed 5-12 months after TAVR, despite a reduction in renal function. Our findings imply that gastrointestinal blood loss, which occurs in patients with severe AS, is significantly reduced following TAVR.

Calcium channel blockers and clinical outcomes in patients with continuous-flow left ventricular assist devices

AIMS

Current guidelines suggest calcium channel blockers (CCBs) as the second or third option for blood pressure management in patients with left ventricular assist device (LVAD). However, the clinical outcomes of patients with LVAD who receive CCBs remain unclear. Our study aims to analyse the association of CCBs with clinical outcomes in patients after LVAD implantation.

METHODS AND RESULTS

This is a retrospective analysis based on the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) from 2006 to 2017, and adult patients who were alive with LVAD and CCB treatment information at 6 months after implantation were included. Among 10 717 patients, 1369 received CCBs 6 months after implantation, and there was an increasing trend of CCB use after LVAD. Patients receiving CCB therapy at 6 months had a similar 5 year survival rate to those not receiving CCB [49.6%, 95% confidence interval (CI): 47.5-51.7% vs. 51.1%, 95% CI: 45.3-56.7%]. In both Cox and competing risk regressions after adjusting for confounding factors, CCB treatment at 6 months after implantation was not associated with long-term mortality [hazard ratio (HR): 1.03, 95% CI: 0.91-1.17, P = 0.624 and subdistribution HR (SHR): 1.07, 95% CI: 0.95-1.22, P = 0.260]. Consistently, in time-varying models, CCB treatment was not linked to long-term mortality (HR: 0.97, 95% CI: 0.87-1.09, P = 0.682 and SHR: 1.05, 95% CI: 0.94-1.18, P = 0.359). This null association remained in subgroup analysis according to device strategy and propensity-matching analyses. Neurological dysfunction, stroke, bleeding, rehospitalization, and renal dysfunction were more likely to occur among those with CCB when compared with those without CCB treatment.

CONCLUSIONS

In patients with LVAD, CCB therapy fails to show benefits in long-term survival and is associated with increased incidences of neurological dysfunction, bleeding, renal dysfunction, and rehospitalization.

Left Ventricular Assist Device Emergencies: Diagnosis and Management

Durable left ventricular assist devices (LVADs) are a virtually limitless advanced therapy option for an increasingly growing population of patients with end-stage advanced heart failure. As of 2019, 30% to 40% of all patients diagnosed with heart failure were categorized as New York Heart Association class III or IV. In 2018 more than 3.2 million office visits and 1.4 million emergency department visits carried a primary diagnosis of heart failure. Given the rapid growth of the LVAD population, facility in the diagnosis and management of common perioperative and outpatient LVAD emergencies has become of paramount importance in a variety of clinical settings.

Gastrointestinal Bleeding in Patients Supported with Left Ventricular Assist Devices: The Journey from Bridging to Destination

End-stage heart failure is a prevalent and fatal cardiovascular disease. Almost 1 in 4 cases of mortality in the United States is attributed to heart failure. Left ventricular assist devices (LVADs) have emerged as a safe destination therapy or bridge to transplant. Despite remarkable results, LVAD is associated with significant adverse events, such as gastrointestinal bleeding (GIB). In this review, we aimed to understand the incidence and prevalence, pathophysiologic mechanisms, predictors, diagnostic mechanisms, management, and preventative measures of GIB in patients with an LVAD. GIB is a common adverse event in patients with an LVAD with an incidence of 15% to 25%. The exact pathogenesis of GIB is poorly understood. However, different mechanisms of bleeding have been described, such as arteriovenous malformations, acquired von Willebrand syndrome, coagulopathy, and treatment with antithrombotic therapy. Upper GIB is the most common site of GIB in patients with an LVAD. The management of GIB in patients with LVAD includes ensuring hemodynamic stability, holding or reversing antithrombotic therapy, and investigating and controlling the source of GIB through diagnostic and interventional endoscopic and radiologic means. Prophylactic medication use (e.g., danazol, octreotide, and bevacizumab) can decrease the risk of GIB in patients with an LVAD by decreasing arteriovenous malformations. Despite that the overall risk of GIB has decreased with new advancements in LVAD technology, further studies are needed regarding predictors, risk stratification, and optimal antithrombotic therapy to minimize the morbidity and mortality in patients with an LVAD. In conclusion, prompt diagnosis and management in a multidisciplinary team approach are crucial and lifesaving in such a life-threatening condition.

von Willebrand Factor and Angiopoietin-2 are Sensitive Biomarkers of Pulsatility in Continuous-Flow Ventricular Assist Device Patients

Nonsurgical bleeding occurs in a significant proportion of patients implanted with continuous-flow ventricular assist devices (CF-VADs) and is associated with nonphysiologic flow with diminished pulsatility. An in vitro vascular pulse perfusion model seeded with adult human aortic endothelial cells (HAECs) was used to identify biomarkers sensitive to changes in pulsatility. Diminished pulsatility resulted in an ~45% decrease in von Willebrand factor (vWF) levels from 9.80 to 5.32 ng/ml (n = 5, p < 0.05) and a threefold increase in angiopoietin-2 (ANGPT-2) levels from 775.29 to 2471.93 pg/ml (n = 5, p < 0.05) in cultured HAECs. These changes are in agreement with evaluation of patient blood samples obtained pre-CF-VAD implant and 30-day postimplant: a decrease in plasma vWF level by 50% from ~45.59 to ~22.49 μg/ml (n = 15, p < 0.01) and a 64% increase in plasma ANGPT-2 level from 7,073 to 11,615 pg/ml (n = 8, p < 0.05). This study identified vWF and ANGPT-2 as highly sensitive to changes in pulsatility, in addition to interleukin-6 (IL-6), IL-8, and tumor necrosis-α (TNF-α). These biomarkers may help determine the optimal level of pulsatility and help identify patients at high risk of nonsurgical bleeding.

A Multicenter Study of Left Ventricular Assist Device-Related Gastrointestinal Bleeding

INTRODUCTION

Continuous left ventricular assist devices (LVADs) offer hemodynamic support in advanced and decompensated heart failure but are often complicated by gastrointestinal bleeding (GIB) in medically fragile patients.

METHODS

We performed a retrospective analysis of 475 consecutive patients who underwent LVAD implantation at the Massachusetts General Hospital and Tufts Medical Center from 2008 to 2019 and identified 128 patients with clinically significant GIB. Clinical characteristics of each bleeding event, including procedures and interventions, were recorded. We examined LVAD patients with overt and occult presentations to determine diagnostic endoscopic yield and analyzed predictors of recurrent GIB.

RESULTS

We identified 128 unique patients with LVAD implantation complicated by GIB. No significant difference was observed based on study center, underlying cardiomyopathy, race/ethnicity, serum indices, and medications used. Overt bleeders presented more commonly during LVAD implantation admission ( P = 0.001) than occult bleeders. Occult bleed presentations had only 1 lower and no middle GI bleed source identified, despite similar workups to overt bleeds. Destination therapy (e.g., among nontransplant candidates) LVAD implantation (odds ratio 2.38, 95% confidence interval 1.05-5.58) and a history of GIB (odds ratio 3.85, 95% confidence interval 1.29-12.7) were independently associated with an increased risk of recurrent GIB-related hospitalization.

DISCUSSION

Our findings confirm a high rate of GIB, especially in destination LVAD patients, and show a low diagnostic yield for colonoscopy and middle GI bleed assessments in LVAD patients with occult bleeds. Overt bleeding was more common and associated with vascular malformations. Although endoscopic interventions stopped active hemorrhage, GIB often recurred.

Severe Pulmonary Bleeding after Assist Device Implantation: Incidence, Risk Factors and Prognostic Impact

Background: Continuous flow left ventricular assist devices (CF-LVAD) improve survival in patients with advanced heart failure but confer risk of bleeding complications. Whereas pathophysiology and risk factors for many bleeding complications are well investigated, the literature lacks reports about pulmonary bleeding. Therefore, it was the aim of the present study to assess incidence, risk factors, and clinical relevance of pulmonary bleeding episodes after LVAD implantation. Methods: We retrospectively analyzed our institutional database of 125 consecutive patients who underwent LVAD implantation between 2008 and 2017. Demographic and clinical variables related to bleeding were collected. The primary endpoint was incidence of severe pulmonary bleeding (SPB). Results: Nine out of 125 patients suffered from SPB during the postoperative course (7.2%) 11 days after surgery in the median. None of them had a known history of lung disease or bleeding disorder. History of prior myocardial infarction (0% vWD. 42.2%, p = 0.012) and ischemic cardiomyopathy (25.0% vs. 50.0%, p = 0.046) were less frequent in the SBP group. Concomitant aortic valve replacement was more common in the group with SPB (33.3% versus 7.0%, p = 0.034). Surgical (blood loss 9950 vs. 3800 mL, p = 0.012) as well as ear-nose-throat (ENT) bleedings (33% vs. 4.6%, p = 0.015) were observed more frequently in patients with SPB. SPB was associated with a complicated postoperative course with a higher incidence of acute kidney failure (100% versus 36.7%, p = 0.001) and delirium (44.4% versus 14.8%, p = 0.045); a higher need for red blood cell (26 packs versus 7, p < 0.001), fresh frozen plasma (18 units versus 6, p = 0.002), and platelet transfusion (8 pools versus 1, p = 0.001); longer ventilation time (1206 versus 171 h, p = 0.001); longer ICU-stay (58 versus 13 days, p = 0.002); and higher hospital mortality (66.7% vs. 29%, p = 0.029). Conclusion: SPB is a rare but serious complication after LVAD implantation and is significantly associated with higher morbidity and mortality. The pathophysiology and potential risk factors are unknown but may include coagulation disorders and frequent suctioning or empiric bronchoscopy causing airway irritation.

Antiplatelet and anticoagulation strategies for left ventricular assist devices

Left ventricular assist devices (LVAD) have revolutionized the management of advanced heart failure. However, complications rates remain high, among which hemorrhagic and thrombotic complications are the most important. Antiplatelet and anticoagulation strategies form a cornerstone of LVAD management and may directly affect LVAD complications. Concurrently, LVAD complications influence anticoagulation and anticoagulation management. A thorough understanding of device, patient, and management, including anticoagulation and antiplatelet therapies, are important in optimizing LVAD outcomes. This article provides a comprehensive state of the art review of issues related to antiplatelet and anticoagulation management in LVADs. We start with a historical overview, the epidemiology and pathophysiology of bleeding and thrombotic complications in LVADs. We then discuss platelet and anticoagulation biology followed by considerations prior to, during, and after LVAD implantation. This is followed by discussion of anticoagulation and the management of thrombotic and hemorrhagic complications. Specific problems, including management of heparin-induced thrombocytopenia, anticoagulant reversal, novel oral anticoagulants, artificial heart valves, and noncardiac surgeries are covered in detail.

Cardiac Emergencies in Patients with Left Ventricular Assist Devices

Continuous-flow left ventricular assist devices are frequently used for management of patients with advanced heart failure with reduced ejection fraction. Although technologic advancements have contributed to improved outcomes, several complications arise over time. These complications result from several factors, including medication effects, physiologic responses to chronic exposure to circulatory support that is minimally/entirely nonpulsatile, and dysfunction of the device itself. Clinical presentation can range from chronic and indolent to acute, life-threatening emergencies. Several areas of uncertainty exist regarding best practices for managing complications; however, growing awareness has led to development of new guidelines to reduce risk and improve outcomes.

Anesthesia at the Edge of Life: Mechanical Circulatory Support

Mechanical circulatory support devices are increasingly being used for patients presenting with heart failure. The primary goal of these devices is to maintain perfusion to all organs. Intra-aortic balloon pump and extracorporeal membrane oxygenators are temporary devices that are usually reserved for patients presenting with acute heart failure. A left ventricular assist device may be implanted either as a bridge to heart transplant or to cardiac recovery, or for destination therapy in refractory heart failure. Familiarization with these devices is key to patient management in the perioperative period, especially for patients presenting for noncardiac surgeries.

Left ventricular assist devices and their complications: A review for emergency clinicians

INTRODUCTION

End stage heart failure is associated with high mortality. However, recent developments such as the ventricular assist device (VAD) have improved patient outcomes, with left ventricular assist devices (LVAD) most commonly implanted.

OBJECTIVE

This narrative review evaluates LVAD epidemiology, indications, normal function and components, and the assessment and management of complications in the emergency department (ED).

DISCUSSION

The LVAD is a life-saving device in patients with severe heart failure. While first generation devices provided pulsatile flow, current LVAD devices produce continuous flow. Normal components include the pump, inflow and outflow cannulas, driveline, and external controller. Complications related to the LVAD can be divided into those that are LVAD-specific and LVAD-associated, and many of these complications can result in severe patient morbidity and mortality. LVAD-specific complications include device malfunction/failure, pump thrombosis, and suction event, while LVAD-associated complications include bleeding, cerebrovascular event, infection, right ventricular failure, dysrhythmia, and aortic regurgitation. Assessment of LVAD function, patient perfusion, and mean arterial pressure is needed upon presentation. Electrocardiogram and bedside ultrasound are key evaluations in the ED. LVAD evaluation and management require a team-based approach, and consultation with the LVAD specialist is recommended.

CONCLUSION

Emergency clinician knowledge of LVAD function, components, and complications is integral in optimizing care of these patients.

Left Ventricular Assist Device Management in the Emergency Department

The prevalence of patients living with a left ventricular assist device (LVAD) is rapidly increasing due to improvements in pump technology, limiting the adverse event profile, and to expanding device indications. To date, over 22,000 patients have been implanted with LVADs either as destination therapy or as a bridge to transplant. It is critical for emergency physicians to be knowledgeable of current ventricular assist devices (VAD), and to be able to troubleshoot associated complications and optimally treat patients with emergent pathology. Special consideration must be taken when managing patients with VADs including device inspection, alarm interpretation, and blood pressure measurement. The emergency physician should be prepared to evaluate these patients for cerebral vascular accidents, gastrointestinal bleeds, pump failure or thrombosis, right ventricular failure, and VAD driveline infections. Early communication with the VAD team and appropriate consultants is essential for emergent care for patients with VADs.