Ventricular septal defect complicating acute myocardial infarction: diagnosis and management. A Clinical Consensus Statement of the Association for Acute CardioVascular Care (ACVC) of the ESC, the European Association of Percutaneous Cardiovascular Interventions (EAPCI) of the ESC and the ESC Working Group on Cardiovascular Surgery.

Ventricular septal defects are a rare complication after acute myocardial infarction with a mortality close to 100% if left untreated. However, even surgical or interventional closure is associated with a very high mortality and currently no randomized controlled trials are available addressing the optimal treatment strategy of this disease. This state-of-the-art review and clinical consensus statement will outline the diagnosis, hemodynamic consequences and treatment strategies of ventricular septal defects complicating acute myocardial infarction with a focus on current available evidence and a focus on major research questions to fill the gap in evidence.

Fully magnetically centrifugal left ventricular assist device and long-term outcomes: the ELEVATE registry.

BACKGROUND AND AIMS: HeartMate 3 (HM3) is a fully magnetically levitated continuous flow left ventricular assist device, which received CE marking in 2015. The ELEVATE Registry was initiated to collect real-world outcomes in patients treated with HM3 post-CE Mark approval. METHODS: A total of 540 subjects implanted at 26 centres between March 2015 and February 2017 were included in this registry. Of these, 463 received the device as a primary implant (primary implant cohort, PIC), 19 as a pump exchange (pump exchange cohort), and in 58 patients, only anonymized survival data were collected (anonymized cohort, AC). Patients in the PIC contributed to the baseline demographics, survival, adverse events, quality of life (QoL) (EuroQoL-5 Dimensions-5 Levels visual analogue scale), and functional capacity (6 min walk distance) assessments, while patients in the AC contributed only to survival. RESULTS: Primary implant cohort patients had a mean age of 56 years and were predominantly male (89%) with 48% ischaemic aetiology. The majority of subjects was designated bridge to transplant (66%) and had INTERMACS Profiles 1-3 (70%). At baseline, the subjects had poor functional capacity (104 ± 140 m) and impaired QoL (35 ± 19 points). The overall survival rate of the PIC was 63.3% and survival free of stroke was 58.1% at 5 years. Significant improvements in functional capacity and QoL were observed and maintained for 5 years (301 ± 131 m and 64 ± 20 points, respectively). CONCLUSIONS: Real-world data from the ELEVATE registry demonstrate an overall survival rate for primary implants of 63.3%. In the PIC, reductions in adverse events for patients in the extended follow-up and improved QoL and functional capacity were observed at 5 years in this patient population with advanced heart failure.

OPTN/SRTR 2022 Annual Data Report: Heart.

The number of heart transplants in the United States has continued to increase. Since 2011, pediatric heart transplants have increased 31.7% to 494 and adult heart transplants have increased 85.8% to 3,668 in 2022. The numbers of new candidates for pediatric and adult heart transplants have also increased, with 703 new pediatric candidates and 4,446 new adult candidates in 2022. Adult heart transplant rates continue to rise, peaking at 122.5 transplants per 100 patient-years in 2022; however, the pediatric heart transplant rate decreased to its lowest rate in the past decade, 104.2 transplants per 100 patient-years, a decrease of 13.9% from 121 transplants per 100 patient-years in 2011. Despite this, pretransplant mortality among pediatric candidates has decreased by 52.2%, from 20.8 deaths per 100 patient-years in 2011 to 10.0 deaths per 100 patient-years in 2022, but remains excessive for candidates younger than 1 year at 25.7 deaths per 100 patient-years. Among adult candidates, pretransplant mortality declined from 15 deaths per 100 patient-years in 2011 to 8.7 deaths per 100 patient-years in 2022. Since 2011, posttransplant mortality has been stable to slightly better; among recipients who underwent transplant in 2015-2017, the 1-, 3-, and 5-year pediatric survival rates were 93.7%, 89.2%, and 85.0%, respectively, and the adult survival rates were 91.3%, 85.7%, and 80.4%. Donor trends have been favorable, with an increase in the numbers of hearts recovered and growing numbers of hearts procured after circulatory death.

Contemporary Care and Outcomes of Critically-ill Children With Clinically Diagnosed Myocarditis.

PURPOSE: To describe contemporary management and outcomes in children with myocarditis who are admitted to a cardiac intensive care unit (CICU) and to identify the characteristics associated with mortality. METHODS: All patients in the Pediatric Cardiac Critical Care Consortium (PC4) registry between August 2014 and June 2021 who were diagnosed with myocarditis were included. Univariable analyses and multivariable logistic regression evaluated the factors associated with in-hospital mortality. RESULTS: There were 847 CICU admissions for myocarditis in 51 centers. The median age was 12 years (IQR 2.7-16). In-hospital mortality occurred in 53 patients (6.3%), and 60 (7.1%) had cardiac arrest during admission. Mechanical ventilation was required in 339 patients (40%), and mechanical circulatory support (MCS) in 177 (21%); extracorporeal membrane oxygenation (ECMO)-only in 142 (16.7%), ECMO-to-ventricular assist device (VAD) in 20 (2.4%), extracorporeal cardiac resuscitation in 43 (5%), and VAD-only in 15 (1.8%) patients. MCS was associated with in-hospital mortality; 20.3% receiving MCS died compared to 2.5% without MCS (P < 0.001). Mortality rates were similar in ECMO-only, ECMO-to-VAD and VAD-only groups. The median time from CICU admission to ECMO was 2.0 hours (IQR 0-9.4) and to VAD, it was 9.9 days (IQR 6.3-16.8). Time to MCS was not associated with mortality. In multivariable modeling of patients' characteristics, smaller body surface area (BSA) and low eGFR were independently associated with mortality, and after including critical therapies, mechanical ventilation and ECMO were independent predictors of mortality. CONCLUSION: This contemporary cohort of children admitted to CICUs with myocarditis commonly received high-resource therapies; however, most patients survived to hospital discharge and rarely received VAD. Smaller patient size, acute kidney injury and receipt of mechanical ventilation or ECMO were independently associated with mortality.

A Novel Predictive Score Model for Successful Weaning From Mechanical Circulatory Support in Patients With Cardiogenic Shock.

BACKGROUND: Clinical evidence regarding predictors of successful weaning from mechanical circulatory support (MCS) is lacking. This study aimed to create a simple risk score to predict successful weaning from MCS in patients with cardiogenic shock. METHODS AND RESULTS: This retrospective single-center cohort study included 114 consecutive patients with cardiogenic shock treated with venoarterial extracorporeal membrane oxygenation or IMPELLA between January 2013 and June 2023. Patients with out-of-hospital cardiac arrest were excluded. The primary end point was successful weaning from MCS, defined as successful decannulation without the need for MCS reimplantation and survival to discharge. Multivariable logistic regression with a stepwise variable selection was performed to generate the prediction model. We first developed a general weaning score model, and then created a simple version of the score model using the same variables. Fifty-five patients were weaned from MCS successfully. The following variables measured during weaning evaluation were selected as the components of the weaning score model: acute myocardial infarction (AMI), mean blood pressure, left ventricular ejection fraction (LVEF), lactate level, and QRS duration. According to the results, we conducted a novel weaning score model to predict successful weaning from MCS: 1.774 - 2.090 × (AMI) + 0.062 × [mean blood pressure (mm Hg)] + 0.139 × [LVEF (%)] - 0.322 × [Lactate (mg/dL)] - 0.066 × [QRS (ms)]. The following variables were selected as the components of the simple version of the weaning score model: AMI, mean blood pressure of ≥80 mm Hg, lactate of <10 mg/dL, QRS duration of ≤95 ms, and LVEF of >35%. CONCLUSIONS: We developed a simple model to predict successful weaning from MCS in patients with cardiogenic shock.

Modes of Death in Patients with Cardiogenic Shock in the Cardiac Intensive Care Unit: A Report from the Critical Care Cardiology Trials Network.

BACKGROUND: There are limited data on how patients with cardiogenic shock (CS) die. METHODS: The Critical Care Cardiology Trials Network is a research network of cardiac intensive care units coordinated by the Thrombolysis In Myocardial Infarction (TIMI) Study Group (Boston, MA). Using standardized definitions, site investigators classified direct modes of in-hospital death for CS admissions (October 2021 to September 2022). Mutually exclusive categories included 4 modes of cardiovascular death and 4 modes of noncardiovascular death. Subgroups defined by CS type, preceding cardiac arrest (CA), use of temporary mechanical circulatory support (tMCS), and transition to comfort measures were evaluated. RESULTS: Among 1068 CS cases, 337 (31.6%) died during the index hospitalization. Overall, the mode of death was cardiovascular in 82.2%. Persistent CS was the dominant specific mode of death (66.5%), followed by arrhythmia (12.8%), anoxic brain injury (6.2%), and respiratory failure (4.5%). Patients with preceding CA were more likely to die from anoxic brain injury (17.1% vs 0.9%; P < .001) or arrhythmia (21.6% vs 8.4%; P < .001). Patients managed with tMCS were more likely to die from persistent shock (P < .01), both cardiogenic (73.5% vs 62.0%) and noncardiogenic (6.1% vs 2.9%). CONCLUSIONS: Most deaths in CS are related to direct cardiovascular causes, particularly persistent CS. However, there is important heterogeneity across subgroups defined by preceding CA and the use of tMCS.

The Future of Durable Mechanical Circulatory Support: Emerging Technological Innovations and Considerations to Enable Evolution of the Field.

The field of durable mechanical circulatory support (MCS) has undergone an incredible evolution over the past few decades, resulting in significant improvements in longevity and quality of life for patients with advanced heart failure. Despite these successes, substantial opportunities for further improvements remain, including in pump design and ancillary technology, perioperative and postoperative management, and the overall patient experience. Ideally, durable MCS devices would be fully implantable, automatically controlled, and minimize the need for anticoagulation. Reliable and long-term total artificial hearts for biventricular support would be available; and surgical, perioperative, and postoperative management would be informed by the individual patient phenotype along with computational simulations. In this review, we summarize emerging technological innovations in these areas, focusing primarily on innovations in late preclinical or early clinical phases of study. We highlight important considerations that the MCS community of clinicians, engineers, industry partners, and venture capital investors should consider to sustain the evolution of the field.

Left Ventricular Unloading Using Intra-Aortic Entrainment Pumping Before Reperfusion Reduces Post-AMI Infarct Size.

BACKGROUND: Anterior myocardial infarction standard of care prioritizes swift coronary reperfusion. Recent studies show left ventricular (LV) unloading with transvalvular axial-flow pumps for 30 minutes before reperfusion (versus immediate reperfusion) reduces 28-day infarct size. Intra-aortic entrainment pumping, using hardware located away from the heart to provide support throughout the cardiac cycle, reduce effective systemic vascular resistance, and augment visceral blood flow and pressure, may reproduce this benefit with reduced risk. This study characterized hemodynamic effects of unloading before and during reperfusion using intra-aortic entrainment pumping and investigated whether unloading reduced anterior myocardial infarction (AMI) scar size. METHODS AND RESULTS: Yorkshire swine were subjected to 90 minutes of left anterior descending artery balloon occlusion and randomly assigned to immediate reperfusion (n=6) versus 30 minutes unloading before reperfusion followed by 120 minutes further unloading (n=7). Unloading was achieved using percutaneous entrainment pumping in the descending aorta. The AMI model matches that used in recent transvalvular pumping studies. Mortality before randomization was 22%. After randomization, mortality was 36% for immediate reperfusion and 0% for unloading. Unloading showed immediate hemodynamic benefit that increased through reperfusion and continued support, leading to distinct differences in cardiac function between groups after 30 minutes of reperfusion. Unloading increased stroke volume and cardiac efficiency at this timepoint relative to pre-occlusion baseline and reduced 28-day LV scar size by 37-45%. CONCLUSIONS: We present the first preclinical data showing extra-cardiac LV unloading before coronary reperfusion using intra-aortic entrainment pumping decreases 28-day infarct size. Extra-cardiac unloading to reduce LV scar size may provide an alternative to transvalvular pumping with potential advantages including reduced risk.

Current status and future directions in pediatric ventricular assist device.

A ventricular assist device (VAD) is a form of mechanical circulatory support that uses a mechanical pump to partially or fully take over the function of a failed heart. In recent decades, the VAD has become a crucial option in the treatment of end-stage heart failure in adult patients. However, due to the lack of suitable devices and more complicated patient profiles, this therapeutic approach is still not widely used for pediatric populations. This article reviews the clinically available devices, adverse events, and future directions of design and implementation in pediatric VADs.

Durable ventricular assist device in adult patients with single ventricle: a systematic literature review.

The worldwide experience with mechanical circulatory support in adult patients with single ventricle and Fontan palliation is limited. We aimed to see the outcomes in such patients on durable left ventricular assist device. We systematically reviewed the English language literature found on PubMed and Google Scholar, searching the terms "Fontan," "single ventricle," "ventricular assist device," "LVAD," and "mechanical circulatory support," and selected all individual cases with reported outcomes. We identified 4 patients on pulsatile left ventricular assist device, all of whom were successfully bridged to transplant, and 15 patients on continuous flow LVAD, age 25.9 ± 5.8, predominantly males. Mean time on LVAD support was 718.6 ± 616.5 days, and only 2 patients (13.3%) died. Durable left ventricular assist device support in adult patients with Fontan provides excellent results and should be used more frequently.

Clinical Application of Extracorporeal Membrane Oxygenation in the Treatment of Fulminant Myocarditis.

Fulminant myocarditis (FM) is a rare but serious clinical syndrome which can be characterized by the rapid deterioration of cardiac function, with cardiogenic shock (CS) and arrhythmic electrical storms being common presentations, often requiring adjunctive support with mechanical circulatory devices. With the development of mechanical circulatory support (MCS) devices, there are now more and more studies investigating the application of MCS in FM patients, and the use of extracorporeal membrane oxygenation (ECMO) to treat FM has shown good survival rates. This review elucidates the treatment of FM, and the application and clinical outcomes associated with ECMO intervention.

Cardiogenic shock severity predicts bleeding events in patients with temporary mechanical circulatory support.

BACKGROUND: Data on shock severity and bleeding events in patients with temporary mechanical circulatory support (tMCS) are limited. We investigated the relationship between the Society for Cardiovascular Angiography and Interventions (SCAI) shock stage classification and bleeding events in patients with tMCS. METHODS: We evaluated the data of 285 consecutive patients with tMCS who were admitted to our institution between June 2019 and May 2022. At the time of tMCS initiation, 81 patients (28.4%) were in SCAI stage A, 38 (13.3%) in stage B, 69 (24.2%) in stage C, 33 (11.6%) in stage D, and 64 (22.5%) in stage E. Multivariable logistic regression modeling was used to assess the association between the SCAI shock stage and in-hospital bleeding events. RESULTS: In-hospital bleeding occurred in 100 patients (35.1%). The bleeding event rate increased incrementally across the SCAI shock stages (stage A, 11.1%; stage B, 15.8%; stage C, 37.7%; stage D, 54.6%; stage E, 64.1%). In-hospital bleeding was associated with the SCAI shock stage (p < 0.001). Compared with stage A, the adjusted odds ratios for in-hospital bleeding were 1.48 (95% confidence interval [CI] 0.47-4.66), 6.47 (95% CI 2.61-10.66), 11.59 (95% CI 3.77-35.64), and 7.85 (95% CI 2.51-24.55) for stages B, C, D, and E, respectively. CONCLUSIONS: The SCAI shock stage predicted subsequent bleeding events in patients with tMCS. This simple scheme may be useful for tailored risk-based clinical assessment and management of patients with tMCS.

Comparison of in-hospital outcomes of ST-elevation myocardial infarction patients with cardiogenic shock receiving left ventricular mechanical circulatory support devices based on transfer status.

BACKGROUND: We aimed to compare outcomes in patients who receive on-site left ventricular mechanical support versus those transferred to other facilities for mechanical support in ST-elevation myocardial infarction (STEMI) patients with cardiogenic shock. METHODS: This retrospective study analyzed data from the 2016 to 2020 Nationwide Inpatient Sample (NIS) database. We identified patients with STEMI and cardiogenic shock who received Impella and LVAD placement during their hospital stay. They were divided into two groups: those with in-house (direct) placement and those transferred to higher-level medical centers. The primary goal was to compare mortality rates between these groups. RESULTS: During the study, 15,934 (75.2%) received in-house left ventricular support, while 5255 (24.8%) were transferred. Mean age (63 vs. 64 years) and female percentage (25 vs. 26%) were similar. The average time from admission to receiving LV support was 0.8 days for direct group versus 2.8 days for transfer group (p < 0.001). Transferred patients had a higher rate of prior heart failure (68 vs. 79%, p < 0.001) and peripheral vascular disease (10 vs. 14%, p < 0.001) but a lower rate of hypertension (23 vs. 17%, p = 0.003). There were no significant differences in other comorbidities. Primary outcome mortality did not significantly differ (44.9 vs. 44.2, p = 0.66). After multivariate analysis, transferred patients had higher rates of ECMO usage, acute kidney injury, renal replacement therapy, major bleeding, and ischemic stroke. Length of stay (8 vs. 15 days, p < 0.001) and total charges ($391,472 vs. $581,183, p < 0.001) were significantly higher in the transferred group. CONCLUSION: Among STEMI patients with cardiogenic shock, our study found no significant difference in mortality between patients transferred for and those with on-site LV support. Those transferred patients experienced more complications, longer length of stay, and increased hospital costs.

Use of percutaneous mechanical circulatory support for right ventricular failure.

BACKGROUND: Utilization of right ventricular mechanical circulatory support (RV-MCS) devices has been limited by a lack of recognition of RV failure as well as a lack of availability and experience with RV-MCS. AIMS: We report a single-center experience with the use of percutaneous RV-MCS and report predictors of adverse outcomes. METHODS: This was a single-center retrospective cohort study. Data from consecutive patients who received RV-MCS for any indication between June 2015 and January 2022 were included. Data on baseline comorbidities, hemodynamics, and laboratory values were collected. The primary outcome was in-hospital mortality analyzed as a logistic outcome in a multivariable model. These variables were further ranked by their predictive value. RESULTS: Among 58 consecutive patients enrolled, the median age was 66 years, 31% were female and 53% were white. The majority of the patients (48%) were hospitalized for acute on chronic heart failure. The majority of the patients were SCAI SHOCK Stage D (67%) and 34 (64%) patients had MCS placed within 24 h of the onset of shock. Before placement of RV-MCS, median central venous pressure (CVP) and RV stroke work index were 20 mmHg and 8.9 g m/m2, respectively. Median serum lactate was 3.5 (1.6, 6.2) mmol/L. Impella RP was implanted in 50% and ProtekDuo in the remaining 50%. Left ventricular MCS was concomitantly used in 66% of patients. Twenty-eight patients (48.3%) died. In these patients, median serum lactate was significantly higher (4.1 [2.3, 13.0] vs. 2.2 [1.4, 4.0] mmol/L, p = 0.007) and a trend toward higher median CVP (24 [18, 31] vs. 19 [14, 24] mmHg, p = 0.052). In the multivariable logistic model, both serum lactate and CVP before RV-MCS placement were independent predictors of in-hospital mortality. Serum lactate had the highest predictive value. CONCLUSION: In our real-world cohort, 52% of patients treated with RV-MCS survived their index hospitalization. Serum lactate at presentation and CVP were the strongest predictors of in-hospital mortality.

Ventriculo-arterial uncoupling with an impella assisted HVAD: The p-D LVAD.

This paper presents the novel use of a temporary percutaneous ventricular assist device (pVAD) in a 51-year-old man with an implanted durable left ventricular assist device (d-LVAD). The pre-existing left ventricular assist device was unable to successfully unload the left ventricle, and the addition of the temporary pVAD achieved successful unloading as well as a decrease in pulmonary artery pressures without compromising the function of the right ventricle allowing safe UNOS listing for orthotopic heart transplantation.

Mechanical circulatory support versus vasopressors alone in patients with acute myocardial infarction and cardiogenic shock undergoing percutaneous coronary intervention.

BACKGROUND: Previous studies have compared Impella use to intra-aortic balloon pump (IABP) use in patients with acute myocardial infarction and cardiogenic shock (AMI-CS) undergoing percutaneous coronary intervention (PCI). Our objective was to compare clinical outcomes in patients with AMI-CS undergoing PCI who received Impella (percutaneous left ventricular assist device) without vasopressors, IABP without vasopressors, and vasopressors without mechanical circulatory support (MCS). METHODS: We queried the National Inpatient Sample (NIS) using ICD-10 codes (2015-2018) to identify patients with AMI-CS undergoing PCI. We created three propensity-matched cohorts to examine clinical outcomes in patients receiving Impella versus IABP, Impella versus vasopressors without MCS, and IABP versus vasopressors without MCS. RESULTS: Among 17,762 patients, Impella use was associated with significantly higher in-hospital major bleeding (31.4% vs. 13.6%; p < 0.001) and hospital charges (p < 0.001) compared to IABP use, with no benefit in mortality (34.1% vs. 26.9%; p = 0.06). Impella use was associated with significantly higher mortality (42.3% vs. 35.7%; p = 0.02), major bleeding (33.9% vs. 22.7%; p = 0.001), and hospital charges (p < 0.001), when compared to the use of vasopressors without MCS. There were no significant differences in clinical outcomes between IABP use and the use of vasopressor without MCS. CONCLUSIONS: In this analysis of retrospective data of patients with AMI-CS undergoing PCI, Impella use was associated with higher mortality, major bleeding, and in-hospital charges when compared to vasopressor therapy without MCS. When compared to IABP use, Impella was associated with no mortality benefit, along with higher major bleeding events and in-hospital charges. A vasopressor-only strategy suggested no difference in clinical outcomes when compared to IABP. This study uses the NIS for the first time to highlight outcomes in AMI-CS patients undergoing PCI when treated with vasopressor support without MCS, compared to Impella and IABP use.

Percutaneous axillary extracorporeal membrane oxygenation supported complex left main bifurcation percutaneous coronary intervention.

A 66-year-old man with multiple comorbidities including severe peripheral artery disease and heart failure with reduced ejection fraction presented with complex coronary artery disease with an elevated Society of Thoracic Surgeons Predicted Risk of Mortality for coronary artery bypass grafting and a Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery score of 18. With a multidisciplinary heart team approach, the patient successfully underwent percutaneous axillary venoarterial extracorporeal membrane oxygenation (VA-ECMO) supported high-risk percutaneous coronary intervention of a heavily calcified left main bifurcation lesion. Given the patient's peripheral artery disease, alternative arterial access for ECMO cannulation was performed percutaneously via the right axillary artery. Additionally, adequate coronary calcium modification was critical to successful stenting of a heavily calcified left main bifurcation. This case highlights a novel approach to obtaining alternative arterial access for ECMO cannulation and emphasizes the importance of calcium modification to achieve excellent stent results.

Biventricular catheterization combined with pressure-volume loop monitoring provides insight into the dynamic effects of left ventricular assist devices ramp on right ventricular function.

Ramp studies are utilized for speed optimization of continuous flow left ventricular assist devices (CF-LVADs). We here report the utility of combined left and right heart catheterization during a ramp study to ensure a comprehensive understanding of the hemodynamic implications on both ventricles. Pressure-volume loop (PV loop) monitoring uncovered compromised systolic and mildly compromised right ventricular function with increasing LVAD speeds, despite improvement in left ventricular unloading. These findings informed patient management and highlight the potential utility of PV loop monitoring as an adjunct to left and right heart catheterization during ramp studies of next-generation LVADs.

Incidence, risk factors, and outcomes of postoperative stroke in combined heart-lung transplantation: A retrospective cohort study of the UNOS registry.

Stroke is a well-characterized complication of isolated heart and lung transplantation, but has not been described in combined heart-lung transplantation (HLTx). We retrospectively reviewed national U.S. data to describe the incidence, risk factors, and impact of postoperative stroke in HLTx recipients. Of 871 heart-lung recipients between 1994-2022, 35 (4.0%) experienced stroke, and the incidence increased over time, trending toward significance (p-trend = .07). After adjustment, extracorporeal membrane oxygenation (ECMO) (Adjusted odds ratio [aOR] = 2.63, 95%CI = [1.13-6.11]) and pre-transplant implantable defibrillator (aOR = 2.86, 95%CI = [1.20-6.81]) were independent risk factors for stroke. Postoperative stroke is common and is increasing in an era where organ allocation is driven by mechanical circulatory support (MCS) bridging.

Bridge-to-transplant temporary mechanical circulatory support and risk of allosensitization.

INTRODUCTION: Since the 2018 change in the US adult heart allocation policy, more patients are bridged-to-transplant on temporary mechanical circulatory support (tMCS). Previous studies indicate that durable left ventricular assist devices (LVAD) may lead to allosensitization. The goal of this study was to assess whether tMCS implantation is associated with changes in sensitization. METHODS: We included patients evaluated for heart transplants between 2015 and 2022 who had alloantibody measured before and after MCS implantation. Allosensitization was defined as development of new alloantibodies after tMCS implant. RESULTS: A total of 41 patients received tMCS before transplant. Nine (22.0%) patients developed alloantibodies following tMCS implantation: 3 (12.0%) in the intra-aortic balloon pump group (n = 25), 2 (28.6%) in the microaxial percutaneous LVAD group (n = 7), and 4 (44.4%) in the veno-arterial extra-corporeal membrane oxygenation group (n = 9)-p = .039. Sensitized patients were younger (44.7 ± 11.6 years vs. 54.3 ± 12.5 years, p = .044), were more likely to be sensitized at baseline - 3 of 9 (33.3%) compared to 2 out of 32 (6.3%) (p = .028) and received more transfusions with red blood cells (6 (66.6%) vs. 8 (25%), p = .02) and platelets (6 (66.6%) vs. 5 (15.6%), p = .002). There was no significant difference in tMCS median duration of support (4 [3,15] days vs. 8.5 [5,14.5] days, p = .57). Importantly, out of the 11 patients who received a durable LVAD after tMCS, 5 (45.5%) became sensitized, compared to 4 out of 30 patients (13.3%) who only had tMCS-p = .028. CONCLUSIONS: Our findings suggest that patients bridged-to-transplant with tMCS, without significant blood product transfusions and a subsequent durable LVAD implant, have a low risk of allosensitization. Further studies are needed to confirm our findings and determine whether risk of sensitization varies by type of tMCS and duration of support.