Access to durable LVAD therapy for patients with limited social support: Surveying program-specific approaches.

Racial and ethnic disparities in provision of left ventricular assist device (LVAD) therapy have been identified. These disparities may be at least partially related to socioeconomic factors, including social support networks and financial constraints. This study aimed to identify specific barriers, and variations in institutional approaches, to the provision of equitable care to underserved populations. A survey was administered to 237 LVAD program personnel, including physicians, LVAD coordinators, and social workers, at more than 100 LVAD centers across 7 countries. Three fourths of respondents reported that their program required a support person to live with the LVAD patient for some period of time following implantation. In addition, 31% of respondents reported that patients with the inability to pay for medications are turned down at their program. The most significant barriers to successful LVAD implantation were lack of social support, lack of insurance, and lack of timely referral. The most consistently identified supports needed from the hospital system for success in underserved populations were the provision of a solution for patient transportation to and from hospital visits and the provision of financial support. This survey highlights the challenges facing LVAD programs that care for underserved patient populations and sets the stage for specific interventions aimed at reducing disparities in access to care.

Hemodynamics Indicates Differences Between Patients With And Without A Stroke Outcome After Left Ventricular Assist Device Implantation.

Stroke remains a leading cause of complications and mortality in heart failure patients treated with LVAD circulatory support. Hemodynamics plays a central role in affecting risk and etiology of stroke during LVAD support. Yet, detailed quantitative assessment of hemodynamic variables and their relation to stroke outcomes in patients with an implanted LVAD remains a challenge. We present an in silico hemodynamics analysis in a set of 12 patients on LVAD support; 6 with reported stroke outcomes and 6 without. We conducted patient-specific hemodynamics simulations for models with the LVAD outflow graft reconstructed from cardiac-gated CT images. A pre-implantation baseline flow model was virtually generated for each case by removing the LVAD outflow graft and driving flow from the aortic root. Hemodynamics was characterized using quantitative descriptors for helical flow, vortex generation, and wall shear stress. Our analysis showed higher average values for descriptors of positive helical flow, vortex generation, and wall shear stress, across the 6 cases with stroke outcomes on LVAD support, when compared with cases without stroke. When the descriptors for LVAD-driven flow were compared against estimated baseline flow pre-implantation, extent of positive helicity was higher, and vorticity and wall shear were lower in cases with stroke compared to those without. The study suggests that quantitative analysis of hemodynamics after LVAD implantation; and hemodynamic alterations from a pre-implant flow scenario, can potentially reveal hidden information linked to stroke outcomes during LVAD support. This has broad implications on understanding stroke etiology, LVAD treatment planning, surgical optimization, and efficacy assessment.

Impella 5.5 support before, during, and after surgical ventricular septal defect repair: A bridge continuum.

INTRODUCTION: Post-infarction ventricular septal defect formation remains a formidable mechanical complication of acute myocardial infarction associated with increased morbidity and mortality. CASE PRESENTATION: We describe the case of a 72-year-old male who was admitted with post-myocardial infarction ventricular septal defect and cardiogenic shock. DISCUSSION: Impella 5.5 with SmartAssist as temporary left ventricular assist device provided sufficient support throughout multiple bridging episodes including failed percutaneous repair and subsequent definitive surgical repair. Contemporary management of post-infarction ventricular septal defect is discussed.

The Relation Between Viscous Energy Dissipation and Pulsation for Aortic Hemodynamics Driven by a Left Ventricular Assist Device.

Left ventricular assist device (LVAD) provides mechanical circulatory support for patients with advanced heart failure. Treatment using LVAD is commonly associated with complications such as stroke and gastro-intestinal bleeding. These complications are intimately related to the state of hemodynamics in the aorta, driven by a jet flow from the LVAD outflow graft that impinges into the aorta wall. Here we conduct a systematic analyses of hemodynamics driven by an LVAD with a specific focus on viscous energy transport and dissipation. We conduct a complementary set of analysis using idealized cylindrical tubes with diameter equivalent to common carotid artery and aorta, and a patient-specific model of 27 different LVAD configurations. Results from our analysis demonstrate how energy dissipation is governed by key parameters such as frequency and pulsation, wall elasticity, and LVAD outflow graft surgical anastomosis. We find that frequency, pulsation, and surgical angles have a dominant effect, while wall elasticity has a weaker effect, in determining the state of energy dissipation. For the patient-specific scenario, we also find that energy dissipation is higher in the aortic arch and lower in the abdominal aorta, when compared to the baseline flow without an LVAD. This further illustrates the key hemodynamic role played by the LVAD outflow jet impingement, and subsequent aortic hemodynamics during LVAD operation.

First-in-Man Use of a Modified Controller to Resolve HVAD Failure-to-Restart.

We report a case of Medtronic HeartWare ventricular assist device (HVAD) pump failure-to-restart. Despite HVAD withdrawal from the market in June 2021, up to 4,000 patients remain on HVAD support worldwide, and many are at high risk for this serious complication. This report describes the first-in-man use of a new HVAD controller that restarted a defective HVAD pump and avoided a fatal outcome. This new controller has the potential of preventing unnecessary VAD exchanges and saving lives.

Quantitative Assessment of Aortic Hemodynamics for Varying Left Ventricular Assist Device Outflow Graft Angles and Flow Pulsation.

Left ventricular assist devices (LVADs) comprise a primary treatment choice for advanced heart failure patients. Treatment with LVAD is commonly associated with complications like stroke and gastro-intestinal (GI) bleeding, which adversely impacts treatment outcomes, and causes fatalities. The etiology and mechanisms of these complications can be linked to the fact that LVAD outflow jet leads to an altered state of hemodynamics in the aorta as compared to baseline flow driven by aortic jet during ventricular systole. Here, we present a framework for quantitative assessment of aortic hemodynamics in LVAD flows realistic human vasculature, with a focus on quantifying the differences between flow driven by LVAD jet and the physiological aortic jet when no LVAD is present. We model hemodynamics in the aortic arch proximal to the LVAD outflow graft, as well as in the abdominal aorta away from the LVAD region. We characterize hemodynamics using quantitative descriptors of flow velocity, stasis, helicity, vorticity and mixing, and wall shear stress. These are used on a set of 27 LVAD scenarios obtained by parametrically varying LVAD outflow graft anastomosis angles, and LVAD flow pulse modulation. Computed descriptors for each of these scenarios are compared against the baseline flow, and a detailed quantitative characterization of the altered state of hemodynamics due to LVAD operation (when compared to baseline aortic flow) is compiled. These are interpreted using a conceptual model for LVAD flow that distinguishes between flow originating from the LVAD outflow jet (and its impingement on the aorta wall), and flow originating from aortic jet during aortic valve opening in normal physiological state.

Challenging Paradigm Limits of Retrograde Cerebral Perfusion During Lower Body Circulatory Arrest.

INTRODUCTION: Retrograde cerebral perfusion (RCP) is a safe and effective technique to augment cerebral protection during lower body circulatory arrest in patients undergoing elective hemiarch replacement. However, recommendations guiding optimal temperature, flow rate, and perfusion pressure are outdated and potentially overly limiting. We report our experience using RCP for elective hemiarch replacement with parameters that challenge the currently accepted paradigm. METHODS: This was a single-center, retrospective analysis of 319 adult patients who underwent elective hemiarch replacement between February 2010 and 2021 using hypothermic lower body circulatory arrest with RCP alone, RCP followed by antegrade cerebral perfusion (ACP), or ACP alone. Flow rates were adjusted to maintain cerebral perfusion pressure between 30 and 50 mm Hg for RCP and between 40 and 60 mm Hg for ACP. RESULTS: RCP was used in 22.6% (n = 72) of cases, whereas ACP alone was performed in 77.4% (n = 247) of cases. Baseline patient characteristics were similar between groups. Patients undergoing RCP demonstrated shorter cross-clamp time (97.0 min versus 100.0 min, P = 0.034) and shorter lower body circulatory arrest time (7.0 min versus 10.0 min, P < 0.0001) compared with ACP alone. Nadir bladder temperature was equivalent between groups (27.3°C versus 27.5°C, P = 0.752). There were no significant differences in postoperative complications, neurologic outcomes, or mortality. CONCLUSIONS: Moderate hypothermic lower body circulatory arrest combined with RCP at target perfusion pressures of 30-50 mm Hg in patients undergoing elective hemiarch replacement results in equivalent neurologic outcomes and overall morbidity to cases using ACP alone. These results challenge the currently accepted paradigm for RCP, which typically uses deep hypothermia while keeping perfusion pressures below 25 mm Hg.

Pathophysiology and management of valvular disease in patients with destination left ventricular assist devices.

Over the last two decades, implantable continuous flow left ventricular assist devices (LVAD) have proven to be invaluable tools for the management of selected advanced heart failure patients, improving patient longevity and quality of life. The presence of concomitant valvular pathology, including that involving the tricuspid, mitral, and aortic valve, has important implications relating to the decision to move forward with LVAD implantation. Furthermore, the presence of concomitant valvular pathology often influences the surgical strategy for LVAD implantation. Concomitant valve repair or replacement is not uncommonly required in such circumstances, which increases surgical complexity and has demonstrated prognostic implications both short and longer term following LVAD implantation. Beyond the index operation, it is also well established that certain valvular pathologies may develop or worsen over time following LVAD support. The presence of pre-existing valvular pathology or that which develops following LVAD implant is of particular importance to the destination therapy LVAD patient population. As these patients are not expected to have the opportunity for heart transplantation in the future, optimization of LVAD support including ameliorating valvular disease is critical for the maximization of patient longevity and quality of life. As collective experience has grown over time, the ability of clinicians to effectively address concomitant valvular pathology in LVAD patients has improved in the pre-implant, implant, and post-implant phase, through both medical management and procedural optimization. Nevertheless, there remains uncertainty over many facets of concomitant valvular pathology in advanced heart failure patients, and the understanding of how to best approach these conditions in the LVAD patient population continues to evolve. Herein, we present a comprehensive review of the current state of the field relating to the pathophysiology and management of valvular disease in destination LVAD patients.

Diagnosis and treatment of right ventricular dysfunction in patients with COVID-19 on veno-venous extra-corporeal membrane oxygenation.

BACKGROUND: Veno-venous (VV) extracorporeal membrane oxygenation (ECMO) is an effective, but highly resource intensive salvage treatment option in COVID patients with acute respiratory distress syndrome (ARDS). Right ventricular (RV) dysfunction is a known sequelae of COVID-19 induced ARDS, yet there is a paucity of data on the incidence and determinants of RV dysfunction on VV ECMO. We retrospectively examined the determining factors leading to RV failure and means of early identification of this phenomenon in patients on VV ECMO. METHODS: The data was extracted from March 2020 to March 2021 from the regional University of Washington Extracorporeal Life Support database. The inclusion criteria included patients > 18 years of age with diagnosis of COVID-19. All had already been intubated and mechanically ventilated prior to VV ECMO deployment. Univariate analysis was performed to identify risk factors and surrogate markers for RV dysfunction. In addition, we compared outcomes between those with and without RV dysfunction. RESULTS: Of the 33 patients that met inclusion criteria, 14 (42%) had echocardiographic evidence of RV dysfunction, 3 of whom were placed on right ventricular assist device support. Chronic lung disease was an independent risk factor for RV dysfunction (p = 0.0002). RV dysfunction was associated with a six-fold increase in troponin I (0.07 ng/ml vs. 0.44 ng/ml, p = 0.039) and four-fold increase in brain natriuretic peptide (BNP) (158 pg/ml vs. 662 pg/ml, p = 0.037). Deep vein thrombosis (DVT, 21% vs. 43%, p = 0.005) and pulmonary embolism (PE, 11% vs. 21%, p = 0.045) were found to be nearly twice as common in the RV dysfunction group. Total survival rate to hospital discharge was 39%. Data trended towards shorter duration of hospital stay (47 vs. 65.6 days, p = 0.15), shorter duration of ECMO support (21 days vs. 36 days, p = 0.06) and improved survival rate to hospital discharge (42.1% vs. 35.7%, p = 0.47) for those with intact RV function compared to the RV dysfunction group. CONCLUSIONS: RV dysfunction in critically ill patients with COVID-19 pneumonia in common. Trends of troponin I and BNP may be important surrogates for monitoring RV function in patients on VV ECMO. We recommend echocardiographic assessment of the RV on such patients.

Venovenous extracorporeal membrane oxygenation support in patients with COVID-19 respiratory failure: A multicenter study.

Objective: The COVID-19 pandemic presents a high mortality rate amongst patients who develop severe acute respiratory distress syndrome (ARDS). The purpose of this study was to evaluate the outcomes of venovenous extracorporeal membrane oxygenation (VV-ECMO) in COVID-19-related ARDS and identify the patients who benefit the most from this procedure. Methods: Adult patients with COVID-19 and severe ARDS requiring VV-ECMO support at 4 academic institutions between March and October 2020 were included. Data were collected through retrospective chart reviews. Bivariate and multivariable analyses were performed with the primary outcome of in-hospital mortality. Results: Fifty-one consecutive patients underwent VV-ECMO with a mean age of 50.4 years; 64.7% were men. Survival to hospital discharge was 62.8%. Median intensive care unit and hospitalization duration were 27.4 days (interquartile range [IQR], 17-37 days) and 34.5 days (IQR, 23-43 days), respectively. Survivors and nonsurvivors had a median ECMO cannulation time of 11 days (IQR, 8-18) and 17 days (IQR, 12-25 days). The average postdecannulation length of stay was 17.5 days (IQR, 12.4-25 days) for survivors and 0 days for nonsurvivors (IQR, 0-6 days). Only 1 nonsurvivor was able to be decannulated. Clinical characteristics associated with mortality between nonsurviors and survivors included increasing age (P = .0048), hemorrhagic stroke (P = .0014), and postoperative dialysis (P = .0013) were associated with mortality in a bivariate model and retained statistical significance in a multivariable model. Conclusions: This multicenter study confirms the effectiveness of VV-ECMO in selected critically ill patients with COVID-19-related severe ARDS. The survival of these patients is comparable to non-COVID-19-related ARDS.

Association of COVID-19 Vaccination With Risk of COVID-19 Infection, Hospitalization, and Death in Heart Transplant Recipients.

Importance: Orthotopic heart transplant (OHT) recipients are at increased risk for morbidity and mortality after SARS-CoV-2 infection. Although antibody response to COVID-19 vaccination is lower in solid organ transplant recipients, there has been no study assessing the safety and effectiveness of COVID-19 vaccination in OHT recipients. Objective: To assess the safety and effectiveness of COVID-19 vaccination and associations with SARS-CoV-2 infection and clinical outcomes in a large population of adult OHT recipients. Design, Setting, and Participants: This case-control study examined data from a US heart transplant program at a single center for all adult recipients of OHT who were followed up from January 15, 2021, through January 31, 2022. Main Outcomes and Measures: The primary outcome was number of SARS-CoV-2 infections and related hospitalizations, intensive care unit (ICU) admissions, and deaths between vaccinated vs unvaccinated adult recipients of OHT. Results: A total of 436 patients who received OHT were included in the study, of which 106 patients were infected with COVID-19. The mean (SD) age was 54 (17) years; 303 (69.5%) were men and 133 (30.5%) were women. There were 366 patients in the vaccinated cohort with 72 COVID-19 infections (19.7%), 15 hospitalizations (4.1%), 4 ICU admissions (1.1%), and 3 deaths (0.8%). There were 70 patients in the unvaccinated cohort with 34 COVID-19 infections (48.6%), 10 hospitalizations (14.3%), 3 ICU admissions (4.3%), and 3 deaths (4.3%). COVID-19 vaccination was associated with a lower risk of COVID-19 infection (risk ratio [RR], 0.41; 95% CI, 0.30-0.56), hospitalization (RR, 0.29; 95% CI, 0.14-0.61), and death (RR, 0.19; 95% CI, 0.05-0.82). Among the 366 vaccinated OHT recipients, there was no echocardiographic evidence of graft dysfunction, clinically significant rejection, or allosensitization at 6 months after they received the COVID-19 vaccine. Conclusions and Relevance: Patients with OHT who are infected with SARS-CoV-2 are at greater risk of severe infection and death compared with immunocompetent individuals. COVID-19 vaccination was associated with fewer COVID-19 infections, hospitalizations, and deaths, with no heart transplant-specific adverse events. COVID-19 vaccination for all OHT recipients is of paramount importance.

Appraisal of Donation After Circulatory Death: How Far Could We Expand the Heart Donor Pool?

BACKGROUND: the incidence of organ donation after circulatory death (DCD) is increasing; however, heart use has lagged behind other solid organs. Ex vivo perfusion devices are under United States Food and Drug Administration review for use in DCD heart recovery. This study sought to measure the potential increase in the donor pool if DCD heart donation becomes widely adopted. METHODS: DCD donor data were obtained from Organ Procurement and Transplantation Network database. Selection criteria included donor age 18 to 49 years, donors meeting Maastricht III criteria, warm ischemia time ≤30 minutes, and donation between 2015 and 2020. Exclusion criteria were coronary disease, prior myocardial infarction, ejection fraction <0.50, significant valve disease, bacteremia, pulmonary capillary wedge pressure >15 mm Hg, and history of HIV/hepatitis C virus infections. RESULTS: There were 12 813 DCD donors during this period, of which 3528 met study criteria, and 70 hearts (2%) were transplanted. The use of DCD hearts would represent an additional 48 heart transplants per month, which corresponds to a 21% (3458 of 16 521) increase across the country. Median warm ischemia was 23 minutes, with no difference between hearts that were or were not transplanted (23 vs 22.5 minutes, P = .97). The frequency with which other organs were successfully transplanted was kidney, 92%; liver, 44%; lung, 7%; intestine, 0%; and pancreas, 2%. CONCLUSIONS: Wide adoption of DCD heart transplantation could yield a substantial increase in the donor pool size, with approximately 580 additional organs being available each year across the United States. This would represent the largest increase in the donor pool in the modern era of heart transplantation.

Creatinine elevations from baseline at the time of cardiac surgery are associated with postoperative complications.

OBJECTIVES: Baseline kidney function is a key predictor of postoperative morbidity and mortality. Whether an increased creatinine at the time of surgery, compared with the lowest creatinine in the 3 months before surgery, is associated with poor outcomes has not been evaluated. We examined whether creatinine elevations from "baseline" were associated with adverse postoperative outcomes. METHODS: A total of 1486 patients who underwent cardiac surgery at the University of Colorado Hospital between January 2011 and May 2016 met inclusion criteria. "Change in creatinine from baseline" was defined as the difference between the immediate presurgical creatinine value and the lowest creatinine value within 3 months preceding surgery. Outcomes evaluated were in-hospital mortality, postoperative infection, postoperative stroke, development of stage 3 acute kidney injury, intensive care unit length of stay, and hospital length of stay. Outcomes were adjusted using a balancing score to account for differences in patient characteristics. RESULTS: There were significant increases in the odds of postoperative infection (odds ratio, 1.17; confidence interval, 1.02-1.34; per 0.1 mg/dL increase in creatinine), stage 3 acute kidney injury (odds ratio, 1.44; confidence interval; 1.18-1.75), intensive care unit length of stay (odds ratio, 1.13; confidence interval, 1.01-1.26), and hospital length of stay (odds ratio, 1.09; confidence interval, 1.05-1.13). There was a significant increase in mortality in the unadjusted analysis, although not after adjustment using a balancing score. There was no association with postoperative stroke. CONCLUSIONS: Elevations in creatinine at the time of surgery above the "baseline" level are associated with increased postoperative morbidity. Baseline creatinine should be established before surgery, and small changes in creatinine should trigger heightened vigilance in the postoperative period.

Operative intervention for a central pulmonary artery pseudoaneurysm.

Pulmonary artery (PA) pseudoaneurysms are a rare but potentially lethal diagnosis. They can be further categorized by etiology or location and are typically successfully treated with endovascular therapies. However, they occasionally require operative intervention. Here, we present a case of a patient who presented with a central PA pseudoaneurysm on computed tomography scan with unclear etiology that was initially treated with conservative management. However, this was noted to have rapid enlargement on interval imaging necessitating urgent surgical intervention. The patient underwent a median sternotomy, anterior PA arteriotomy for exposure, exclusion of the posterior artery pseudoaneurysm with a bovine pericardial patch, and closure of the anterior arteriotomy with a bovine pericardial patch. The patient did well and was discharged on postoperative day 11 with repeat imaging showing resolution.