Predictors and Impact of Prolonged Vasoplegia After Continuous-Flow Left Ventricular Assist Device Implantation.

Background: Vasoplegia after cardiac surgery is associated with adverse outcomes. However, the clinical effects of vasoplegia and the significance of its duration after continuous-flow left ventricular assist device (CF-LVAD) implantation are less known. Objectives: This study aimed to identify predictors of and outcomes from transient vs prolonged vasoplegia after CF-LVAD implantation. Methods: The study was a retrospective review of consecutive patients who underwent CF-LVAD implantation between January 1, 2005, and December 31, 2017. Vasoplegia was defined as the presence of all of the following: mean arterial pressure ≤65 mm Hg, vasopressor (epinephrine, norepinephrine, vasopressin, or dopamine) use for >6 hours within the first 24 hours postoperatively, cardiac index ≥2.2 L/min/m2 and systemic vascular resistance <800 dyne/s/cm5, and vasodilatory shock not attributable to other causes. Prolonged vasoplegia was defined as that lasting 12 to 24 hours; transient vasoplegia was that lasting 6 to <12 hours. Patient characteristics, outcomes, and risk factors were analyzed. Results: Of the 600 patients who underwent CF-LVAD implantation during the study period, 182 (30.3%) developed vasoplegia. Mean patient age was similar between the vasoplegia and no-vasoplegia groups. Prolonged vasoplegia (n = 78; 13.0%), compared with transient vasoplegia (n = 104; 17.3%), was associated with greater 30-day mortality (16.7% vs 5.8%; P = 0.02). Risk factors for prolonged vasoplegia included preoperative dialysis and elevated body mass index. Conclusions: Compared with vasoplegia overall, prolonged vasoplegia was associated with worse survival after CF-LVAD implantation. Treatment to avoid or minimize progression to prolonged vasoplegia may be warranted.

Recovery of Lung Function After 149 Days on Extracorporeal Membrane Oxygenation for COVID-19.

This report highlights survival and the patient's perspective after prolonged venovenous extracorporeal membrane oxygenation (ECMO) for COVID-19-related respiratory failure. A 36-year-old man with COVID-19 presented with fever, anosmia, and hypoxia. After respiratory deterioration necessitating intubation and lung-protective ventilation, he was referred for ECMO. After 3 days of conventional venovenous ECMO, he required multiple creative cannulation configurations. Adequate sedation and recurrent bradycardia were persistent challenges. After 149 consecutive days of ECMO, he recovered native lung function and was weaned from mechanical ventilation. This represents the longest-duration ECMO support in a survivor of COVID-19 yet reported. Necessary strategies included unconventional cannulation and flexible anticoagulation.

Leadless pacemaker with transcatheter aortic valve implantation: A single-center experience.

BACKGROUND: The safety and efficacy of leadless pacemakers (LP) in transcatheter aortic valve implant (TAVI) patients is not well known due to paucity of data. Herein, we compared outcomes between leadless pacemakers to traditional dual chamber pacemakers (DCP) following TAVI. METHODS: A single-center retrospective study was conducted, including a total of 27 patients with LP and 33 patients with DCP after TAVI between November 2013 and May 2021. We compared baseline demographics, pacemaker indications, complication rates, percent pacing, and ejection fractions. RESULTS: Leading indications for pacemaker implant were complete heart block (74% LP, 73% DCP) and high degree atrioventricular block (26% LP, 21% DCP). Twenty-two (82%) LP patients had devices implanted in the right ventricular septal-apex. Three (9%) DCP patients required rehospitalization for pocket related complications. Zero pacemaker-related mortality was observed in both groups. Frequency of ventricular pacing and ejection fraction was similar between LP and DCP groups. CONCLUSION: From this single-center retrospective study, LP implant was feasible following TAVI and was found to have comparable performance to DCPs. LPs may be a reasonable alternative in TAVI patients where single ventricular pacing is indicated. Larger studies are required to validate these findings.

Peripheral extracorporeal membrane oxygenation support expands the application of robot-assisted coronary artery bypass.

Objective: Robot-assisted coronary artery bypass (RCAB) is typically not offered to higher risk patients with reduced cardiopulmonary function, critical coronary artery disease, and challenging chest wall anatomy. In this study, we report the novel use of nonemergency intraoperative peripheral extracorporeal membrane oxygenation as partial cardiopulmonary support during RCAB for patients who were considered high-risk candidates for conventional CAB and at the same time not eligible for RCAB without cardiopulmonary support. Methods: Forty-five high risk patients (mean age, 68 years; Society of Thoracic Surgeons score, 6.27%; ejection fraction, 45%) underwent RCAB with nonemergency peripheral extracorporeal membrane oxygenation support for the following indications: inability to tolerate single-lung ventilation (n = 17; 38%), low ejection fraction <35% (n = 17; 38%), inadequate exposure of internal thoracic artery (n = 24; 53%), critical coronary artery disease (n = 16; 36%), and hemodynamic instability after anesthesia induction (n = 3; 7%). Following robotic internal thoracic artery takedown, all patients had beating heart minimally invasive direct CAB through a 2-inch minithoracotomy. Results: Up to 30 days, there were no strokes (0%), myocardial infarctions (0%), or access vessel complications (0%). One noncardiac related mortality (2.2%) was related to hemodialysis access issues in a patient with preexisting end-stage renal disease. One redo-CAB (2.2%) patient required sternotomy to locate the target vessel. Thirty-four (75.6%) patients were extubated within 6 hours of surgery. Conclusions: Our results examine the feasibility of using peripheral extracorporeal membrane oxygenation during RCAB for high-risk patients who otherwise had limited options. The use of peripheral extracorporeal membrane oxygenation in RCAB can potentially expand the surgical treatment options in high-risk coronary artery disease patients.

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.

The influence of preoperative dialysis on survival after continuous-flow left ventricular assist device implantation.

OBJECTIVES: Dialysis is considered a contraindication to continuous-flow left ventricular assist device (CF-LVAD) implantation. We evaluated clinical outcomes and survival in carefully selected, low-risk patients with renal failure who required dialysis before CF-LVAD implantation. METHODS: We extracted medical record data of patients who underwent CF-LVAD placement at our centre between 1 January 2006 and 31 August 2017, with 2 clinical scenarios: those who required long-term (>14 days) dialysis and those who required short-term (≤14 days) dialysis immediately before implantation. Demographic, clinical and intraoperative characteristics and survival outcomes were assessed. RESULTS: Of 621 patients who underwent CF-LVAD implantation during the study period, 31 underwent dialysis beforehand. Of these, 17 required long-term dialysis (13 haemodialysis, 4 peritoneal dialysis), and 14 underwent short-term haemodialysis. Compared with the long-term dialysis patients, the short-term dialysis patients were more likely to be Interagency Registry for Mechanically Assisted Circulatory Support profile 1-2 (92.9% vs 70.6%; P < 0.001), to have needed preoperative mechanical circulatory support (78.6% vs 70.6%; P < 0.01) and to have higher in-hospital mortality (85.7% vs 29.4%; P = 0.01). Patients stable on long-term dialysis had acceptable overall survival and markedly better 6-month and 1-year survival than those with short-term dialysis before implantation (64.7% vs 14.3% and 58.8% vs 7.1%, respectively; P < 0.001). CONCLUSIONS: Carefully selected patients who are stable on long-term dialysis have acceptable survival rates after CF-LVAD implantation. Patients with acute renal failure had much poorer outcomes than those with chronic end-stage renal disease.

Tree-aggregated predictive modeling of microbiome data.

Modern high-throughput sequencing technologies provide low-cost microbiome survey data across all habitats of life at unprecedented scale. At the most granular level, the primary data consist of sparse counts of amplicon sequence variants or operational taxonomic units that are associated with taxonomic and phylogenetic group information. In this contribution, we leverage the hierarchical structure of amplicon data and propose a data-driven and scalable tree-guided aggregation framework to associate microbial subcompositions with response variables of interest. The excess number of zero or low count measurements at the read level forces traditional microbiome data analysis workflows to remove rare sequencing variants or group them by a fixed taxonomic rank, such as genus or phylum, or by phylogenetic similarity. By contrast, our framework, which we call trac (tree-aggregation of compositional data), learns data-adaptive taxon aggregation levels for predictive modeling, greatly reducing the need for user-defined aggregation in preprocessing while simultaneously integrating seamlessly into the compositional data analysis framework. We illustrate the versatility of our framework in the context of large-scale regression problems in human gut, soil, and marine microbial ecosystems. We posit that the inferred aggregation levels provide highly interpretable taxon groupings that can help microbiome researchers gain insights into the structure and functioning of the underlying ecosystem of interest.

SARS-CoV-2 Infects Human Engineered Heart Tissues and Models COVID-19 Myocarditis.

There is ongoing debate as to whether cardiac complications of coronavirus disease-2019 (COVID-19) result from myocardial viral infection or are secondary to systemic inflammation and/or thrombosis. We provide evidence that cardiomyocytes are infected in patients with COVID-19 myocarditis and are susceptible to severe acute respiratory syndrome coronavirus 2. We establish an engineered heart tissue model of COVID-19 myocardial pathology, define mechanisms of viral pathogenesis, and demonstrate that cardiomyocyte severe acute respiratory syndrome coronavirus 2 infection results in contractile deficits, cytokine production, sarcomere disassembly, and cell death. These findings implicate direct infection of cardiomyocytes in the pathogenesis of COVID-19 myocardial pathology and provides a model system to study this emerging disease.

Transcatheter aortic valve replacement after chest radiation: A propensity-matched analysis.

BACKGROUND: Chest radiation therapy (CRT) for malignant thoracic neoplasms is associated with development of valvular heart disease years later. As previous radiation exposure can complicate surgical treatment, transcatheter aortic valve replacement (TAVR) has emerged as an alternative. However, outcomes data are lacking for TAVR patients with a history of CRT. METHODS: We conducted a retrospective study of all patients who underwent a TAVR procedure at a single institution between September 2012 and November 2018. Among 1341 total patients, 50 had previous CRT. These were propensity-matched in a 1:2 ratio to 100 patients without history of CRT. Thirty-day adverse events were analyzed with generalized estimating equation models. Overall mortality was analyzed with stratified Cox regression modelling. RESULTS: Median clinical follow-up was 24 months (interquartile range [IQR], 12-44 months). There was no difference between CRT and non-CRT patients in overall mortality (hazard ratio [HR] 0.84 [0.37-1.90], P = 0.67), 30-day mortality (HR 3.1 [0.49-20.03], P = 0.23), or 30-day readmission rate (HR 1.0 [0.43-2.31], P = 1). There were no differences in the rates of most adverse events, but patients with CRT history had higher rates of postprocedural respiratory failure (HR 3.63 [1.32-10.02], P = 0.01) and permanent pacemaker implantation (HR 2.84 [1.15-7.01], P = 0.02). CONCLUSIONS: For patients with aortic valve stenosis and previous CRT, TAVR is safe and effective, with outcomes similar to those in the general aortic stenosis population. Patients with history of CRT are more likely to have postprocedural respiratory failure and to require permanent pacemaker implantation.

Delayed removal of a percutaneous left ventricular assist device for patients undergoing catheter ablation of ventricular tachycardia is associated with increased 90-day mortality.

PURPOSE: Assess if timing of removal of a percutaneous left ventricular assist device (pLVAD) after ventricular tachycardia (VT) ablation alters patient outcomes. METHODS: Sixty-nine patients underwent pLVAD support. Patients were divided into early (< 24 h, n = 43) and delayed (≥ 24 h, n = 26) removal groups after ablation. Factors for delayed pLVAD removal and predictors of 90-day mortality were analyzed. RESULTS: The delayed removal group had lower LVEF (27.1 ± 9.3% vs. 20.6 ± 5.4%, p = 0.002), greater percentage LVEF < 25% (58.1% vs. 84.6%, p = 0.02), and more VT storm (41.9% vs. 96.2%, p < 0.001). Ventricular fibrillation (VF) was induced in 9/69 (13%), with incidence higher in delayed removal group (27% vs. 5%, p = 0.002). VT storm (OR = 34.72, 95% CI, 4.30-280.33; p = 0.001), LVEF < 25% (OR = 3.95, 95% CI, 1.16-13.48; p = 0.03), and VF induced during ablation (OR = 9.25, 95% CI, 1.71-50.0; p = 0.01) were associated with delayed pLVAD removal in univariate analysis. Delayed pLVAD removal had a significantly higher 90-day mortality rate (2.3% vs 30.2%; p < 0.001). Univariate Cox proportional hazard regression analysis revealed delayed pLVAD removal was a significant predictor of 90-day mortality. CONCLUSIONS: Prolonged pLVAD insertion (≥ 24 h) after VT ablation was associated with VT storm, LVEF < 25%, and VF induced during ablation. Delayed pLVAD removal was a significant predictor of 90-day mortality in patients undergoing VT ablation.

SARS-CoV-2 Infects Human Engineered Heart Tissues and Models COVID-19 Myocarditis.

Epidemiological studies of the COVID-19 pandemic have revealed evidence of cardiac involvement and documented that myocardial injury and myocarditis are predictors of poor outcomes. Nonetheless, little is understood regarding SARS-CoV-2 tropism within the heart and whether cardiac complications result directly from myocardial infection. Here, we develop a human engineered heart tissue model and demonstrate that SARS-CoV-2 selectively infects cardiomyocytes. Viral infection is dependent on expression of angiotensin-I converting enzyme 2 (ACE2) and endosomal cysteine proteases, suggesting an endosomal mechanism of cell entry. After infection with SARS-CoV-2, engineered tissues display typical features of myocarditis, including cardiomyocyte cell death, impaired cardiac contractility, and innate immune cell activation. Consistent with these findings, autopsy tissue obtained from individuals with COVID-19 myocarditis demonstrated cardiomyocyte infection, cell death, and macrophage-predominate immune cell infiltrate. These findings establish human cardiomyocyte tropism for SARS-CoV-2 and provide an experimental platform for interrogating and mitigating cardiac complications of COVID-19.

Outcomes of Repeat Left Ventricular Assist Device Exchange.

Implantable continuous-flow left ventricular assist devices (CF-LVADs) are used for long-term LV support in bridging patients to heart transplantation or as destination therapy. With prolonged support times, some patients will have repeat complications necessitating multiple device exchanges. To elucidate the safety and efficacy of repeat device exchange, we retrospectively reviewed data from 25 patients who underwent two or more CF-LVAD implantations between July 2005 and August 2017. Indications for exchange were thrombus/hemolysis (n = 8, 32%), electromechanical device malfunction (n = 14, 56%), and infection (n = 3, 12%). The implanted devices were the HeartMate II (n = 13, 52%), the HeartWare HVAD (n = 11, 44%), and the Jarvik 2000 (n = 1, 4%). Average hospital length of stay was 44 days (range 4-221 days), and 17 patients (68%) survived to discharge. Average duration of support after the most recent LVAD implantation was 802 days (range 1-3,229 days). Overall survival was 72% at 1 year and 60% at 2 years. Postoperative complications included respiratory failure in five patients (20%), device infection in five (20%), bleeding requiring reoperation in four (16%), neurologic dysfunction in four (16%), and acute renal failure in two (8%). Overall, our data suggest that repeat LVAD exchange is a feasible option for patients with recurrent device-related complications.

Plasmapheresis in Patients With Heparin-induced Thrombocytopenia Requiring Ventricular Assist Device.

Anticoagulation with unfractionated heparin is vital to reduce the risk of thromboembolic events during cardiopulmonary bypass and left ventricular assist device placement. However patients with heparin-induced thrombocytopenia are at risk of developing immune-mediated thrombotic events. We describe 2 patients with heparin-induced thrombocytopenia confirmed via serotonin release assay who were successfully treated with plasmapheresis exchange before left ventricular assist device placement.

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.

Incidence, Predictors, and Significance of Ventricular Arrhythmias in Patients With Continuous-Flow Left Ventricular Assist Devices: A 15-Year Institutional Experience.

OBJECTIVES: The aim of this study was to evaluate the incidence, predictors, and associated mortality of pre-implantation, early, and late ventricular arrhythmias (VAs) in patients receiving continuous-flow left ventricular assist devices (CFLVADs). BACKGROUND: VAs are common both pre- and post-implantation of left ventricular assist devices. Limited data exist on their prognostic impact in contemporary CFLVADs. METHODS: A retrospective review was performed to identify patients who underwent CFLVAD implantation between 2000 and 2015 with 2 years of follow-up. All VAs, defined as ventricular fibrillation, ventricular tachycardia lasting >30 s, or a ventricular rhythm requiring defibrillation, were analyzed. VAs occurring within 30 days of implantation were defined as early. Recorded outcomes included death and receipt of cardiac transplant. RESULTS: A total of 517 patients were included for analysis. Early VAs were associated with a significant reduction in survival (hazard ratio: 1.83; 95% confidence interval: 1.28 to 2.61; p = 0.001) compared with patients with late or no VAs. Pre-implantation variables independently predictive of early VAs included prior cardiac surgery (odds ratio: 1.90; 95% confidence interval: 1.09 to 3.32; p = 0.023) and pre-CFLVAD ventricular tachycardia storm (odds ratio: 3.15; 95% confidence interval: 1.49 to 6.69; p = 0.003). The incidence of early VAs from 2000 to 2007 was as high as 47%, whereas the highest incidence from 2008 to 2015 was <22%. CONCLUSIONS: VAs within 30 days after CFLVAD implantation are associated with an increased risk for death. Predictors of early VAs include prior cardiac surgery and pre-CFLVAD ventricular tachycardia storm. Temporal trends have shown a decrease in VA from 2000 to 2015. Strategies to reduce arrhythmia burden shortly after CFLVAD implantation warrant further investigation.

Bridging to lung transplantation with extracorporeal circulatory support: when or when not?

Patients with end-stage lung disease who are candidates for lung transplantation may acutely decompensate before a donor organ becomes available. In this scenario, extracorporeal life support (ECLS) may be considered as a bridge to transplant or as a bridge to decision. In the current chapter, we review the indications, techniques, and outcomes for bridging to lung transplantation with ECLS.

Outcomes of pre-emptive and rescue use of percutaneous left ventricular assist device in patients with structural heart disease undergoing catheter ablation of ventricular tachycardia.

PURPOSE: Patient selection and timing of percutaneous left ventricular assist device (pLVAD) insertion for maximal benefit during ventricular tachycardia (VT) ablation is not well defined. We aimed to assess the outcomes of pre-emptive and rescue use of pLVAD during VT ablation in patients with ischemic and non-ischemic cardiomyopathy. METHODS: Between January 2009 and October 2011, 93 patients underwent VT ablation. Three groups were compared: (1) Rescue group (n = 12)-patients who required emergent pLVAD insertion due to hemodynamic collapse during VT ablation, (2) Pre-emptive group (n = 24)-patients who had pre-ablation pLVAD insertion, and (3) Non-pLVAD group (n = 57)-patients who did not undergo pLVAD insertion. Procedural outcomes including 30-day mortality were compared. RESULTS: Thirty-day mortality was higher in the Rescue group compared to the Pre-emptive group (58 vs. 4 %, p = 0.003) and non-pLVAD (58 vs. 3 %, p = 0.001) group. There was no significant difference in 30-day mortality or long-term freedom of VT between the pre-emptive and non-pLVAD groups. CONCLUSIONS: Despite rescue pLVAD insertion, hemodynamic collapse during VT ablation is associated with a persistently high 30-day mortality. Further studies are warranted to predict hemodynamic collapse and to refine the role of pLVAD in this setting.

Safety and Feasibility of Open Chest Epicardial Mapping and Ablation of Ventricular Tachycardia During the Period of Left Ventricular Assist Device Implantation.

INTRODUCTION: Patients undergoing catheter ablation for ventricular tachycardia (VT) may require epicardial mapping. In patients with end-stage heart failure, hybrid surgical epicardial mapping and ablation during the period of left ventricular assist device (LVAD) implantation may be considered in select patients to reduce post-LVAD ventricular tachycardia. METHODS AND RESULTS: From March 2009 to October 2012, 5 patients (4 men and 1 woman, age range 52-73 years) underwent open chest electrophysiology study and epicardial mapping for recurrent ventricular tachycardia while the heart was exposed during the period of LVAD implantation. Epicardial mapping was considered if patients had recurrent VT despite failed prior endocardial ablation and/or electrocardiogram (EKG) features of an epicardial exit. Activation and/or a substrate mapping approach were employed during all procedures. Three of 5 patients (60%) had acute procedural success. In all patients, VT was either eliminated or significantly reduced with epicardial ablation. One patient had mediastinal bleeding delaying sternal closure. During a follow-up period of 363 ± 368 days, 4 patients died due to nonarrhythmic causes. CONCLUSIONS: Open-chest hybrid epicardial mapping and ablation for recurrent VT is feasible and can be considered in select patients during the period of LVAD implantation.

The State of the Art in Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation has evolved in design, technology, patient selection, insertion techniques, adjunct devices, and management in the past 45 years since it began. Outcomes have improved and indications have expanded. It continues to be an expeditious, cost-effective tool for rapid resuscitation of patients with cardiorespiratory failure, whose outcomes without extracorporeal membrane oxygenation intervention are predominately fatal. However, results are still moderately satisfactory, and the ethical aspects of ongoing care need to be at the forefront of daily family discussions in patients for whom a bridge to transplant or definitive device is not possible.