Determinants of survival following heart transplantation in adults with congenital heart disease.

BACKGROUND: Adult patients surviving with congenital heart disease (ACHD) is growing. We examine the factors associated with heart transplant outcomes in this challenging population with complex anatomy requiring redo-surgeries. METHODS: We reviewed the United Network for Organ Sharing-Standard Transplant Analysis and Research database and analyzed 35,952 heart transplants from January 1st, 2000, to September 30th, 2018. We compared transplant characteristics for ischemic cardiomyopathy (ICM) (n = 14,236), nonischemic cardiomyopathy (NICM) (n = 20,676), and ACHD (n = 1040). Mean follow-up was 6.20 ± 4.84 years. Kaplan-Meier survival curves and Cox-proportional hazards analysis were used to analyze survival data. RESULTS: Multivariable analysis confirmed that ACHD was associated greater in-hospital death compared to ICM (HR = 0.54, P < 0.001) and NICM (HR = 0.46, P < 0.001). Notable factors associated with increased mortality were history of cerebrovascular disease (HR = 1.11, P = 0.026), prior history of malignancy (HR = 1.12, P = 0.006), pre-transplant biventricular support (HR = 1.12, P = 0.069), postoperative stroke (HR = 1.47, P < 0.001) and postoperative dialysis (HR = 1.71, P < 0.001). ACHD transplants had a longer donor heart ischemic time (P < 0.001) and trend towards more deaths from primary graft dysfunction (P = 0.07). In-hospital deaths were more likely with ACHD and use of mechanical support such as use of right ventricular assist device (HR = 2.20, P = 0.049), biventricular support (HR = 1.62, P < 0.001) and extracorporeal membrane oxygenation (HR = 2.36, P < 0.001). Conditional survival after censoring hospital deaths was significantly higher in ACHD (P < 0.001). CONCLUSION: Heart transplant in ACHD is associated with a higher post-operative mortality given anatomical complexity but a better long-term conditional survival. Normothermic donor heart perfusion may improve outcomes in the ACHD population by reducing the impact of longer ischemic times.

Modeling and estimating a threshold effect: An application to improving cardiac surgery practices.

Estimating thresholds when a threshold effect exists has important applications in biomedical research. However, models/methods commonly used in the biomedical literature may lead to a biased estimate. For patients undergoing coronary artery bypass grafting (CABG), it is thought that exposure to low oxygen delivery (DO2) contributes to an increased risk of avoidable acute kidney injury. This research is motivated by estimating the threshold of nadir DO2 for CABG patients to help develop an evidence-based guideline for improving cardiac surgery practices. We review several models (sudden-jump model, broken-stick model, and the constrained broken-stick model) that can be adopted to estimate the threshold and discuss modeling assumptions, scientific plausibility, and implications in estimating the threshold. Under each model, various estimation methods are studied and compared. In particular, under a constrained broken-stick model, a modified two-step Newton-Raphson algorithm is introduced. Through comprehensive simulation studies and an application to data on CABG patients from the University of Michigan, we show that the constrained broken-stick model is flexible, more robust, and able to incorporate scientific knowledge to improve efficiency. The two-step Newton-Raphson algorithm has good computational performances relative to existing methods.

Cannulation strategies for extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) is a type of extracorporeal life support (ECLS) in which the function of the heart and/or lungs is partially or completely replaced by a portable system that provides prolonged support to critically ill patients with respiratory or cardiac failure. There are two major variants of ECMO: veno-venous (VV) ECMO and veno-arterial (VA) ECMO. VV ECMO replaces the function of the lung in which it uses a cannula to remove venous blood and oxygenates it using the extracorporeal system, and returns the blood to the right atrium to be pumped to the body. VA ECMO is slightly different in that it replaces the function of the heart and lungs by returning oxygenated blood to the aorta. As a therapy for respiratory failure, ECMO minimizes hypoxia, diminishes lung stress and strain, and allows lung protective mechanical ventilation. As a support for acute and terminal heart failure, ECMO reduces preload, increases aortic flow, and allows for end-organ perfusion. Due to its physiological support and advantages, it is used for a variety of chronic and acute support purposes such as bridge therapy for heart/lung transplant, durable ventricular assist devices, and intermediate-term mechanical support postoperatively. Our review gives a broad overview of the two main types of ECMO strategies and their clinical indications, cannulation strategies, unique clinical utility, and their limitations.

Periprocedural Complications With Balloon Pulmonary Angioplasty: Analysis of Global Studies.

BACKGROUND: Balloon pulmonary angioplasty (BPA) was introduced as a treatment modality for patients with inoperable, medically refractory chronic thromboembolic pulmonary hypertension decades ago; however, reports of high rates of pulmonary vascular injury have led to considerable refinement in procedural technique. OBJECTIVES: The authors sought to better understand the evolution of BPA procedure-related complications over time. METHODS: The authors conducted a systematic review of original articles published by pulmonary hypertension centers globally and performed a pooled cohort analysis of procedure-related outcomes with BPA. RESULTS: This systematic review identified 26 published articles from 18 countries worldwide from 2013 to 2022. A total of 1,714 patients underwent 7,561 total BPA procedures with an average follow up of 7.3 months. From the first period (2013-2017) to the second period (2018-2022), the cumulative incidence of hemoptysis/vascular injury decreased from 14.1% (474/3,351) to 7.7% (233/3,029) (P < 0.01); lung injury/reperfusion edema decreased from 11.3% (377/3,351) to 1.4% (57/3,943) (P < 0.01); invasive mechanical ventilation decreased from 0.7% (23/3,195) to 0.1% (4/3,062) (P < 0.01); and mortality decreased from 2.0% (13/636) to 0.8% (8/1,071) (P < 0.01). CONCLUSIONS: Procedure-related complications with BPA, including hemoptysis/vascular injury, lung injury/reperfusion edema, mechanical ventilation, and death, were less common in the second period (2018-2022), compared with first period (2013-2017), likely from refinement in patient and lesion selection and procedural technique over time.

ECMO During COVID-19: A Society of Thoracic Surgeons/Extracorporeal Life Support Organization Survey.

Background: The Society of Thoracic Surgeons Workforce on Critical Care and the Extracorporeal Life Support Organization sought to identify how the coronavirus disease 2019 (COVID-19) pandemic has changed the practice of venoarterial (VA) and venovenous (VV) extracorporeal membrane oxygenation (ECMO) programs across North America. Methods: A 26-question survey covering 6 categories (ECMO initiation, cannulation, management, anticoagulation, triage/protocols, and credentialing) was emailed to 276 North American Extracorporeal Life Support Organization centers. ECMO practices before and during the COVID-19 pandemic were compared. Results: Responses were received from 93 (34%) programs. The percentage of high-volume (>20 cases per year) VV ECMO programs increased during the pandemic from 29% to 41% (P < .001), as did institutions requiring multiple clinicians for determining initiation of ECMO (VV ECMO, 25% to 43% [P = .001]; VA ECMO, 20% to 32% [P = .012]). During the pandemic, more institutions developed their own protocols for resource allocation (23% before to 51%; P < .001), and more programs created sharing arrangements to triage patients and equipment with other centers (31% to 57%; P < .001). Direct thrombin inhibitor use increased for both VA ECMO (13% to 18%; P = .025) and VV ECMO (12% to 24%; P = .005). Although cardiothoracic surgeons remained the primary cannulating proceduralists, VV ECMO cannulations performed by pulmonary and critical care physicians increased (13% to 17%; P = .046). Conclusions: The Society of Thoracic Surgeons/Extracorporeal Life Support Organization collaborative survey indicated that the pandemic has affected ECMO practice. Further research on these ECMO strategies and lessons learned during the COVID-19 pandemic may be useful in future global situations.

Contemporary Management of Ischemic Mitral Regurgitation at Coronary Artery Bypass Grafting.

BACKGROUND: Recent guidelines for the treatment of moderate or severe ischemic mitral regurgitation (IMR) in patients undergoing coronary artery bypass grafting (CABG) have changed. This study assessed the real-world impact of changing guidelines on the management of IMR during CABG over time. We hypothesized that the utilization of mitral valve repair for IMR would decrease over time, whereas mitral valve replacement for severe IMR would increase. METHODS: Patients undergoing CABG in a statewide collaborative database (2011-2020) were stratified by severity of IMR. Trends in mitral valve repair or replacement were evaluated. To account for differences of the patients, propensity score-matched analyses were used to compare patients with and without mitral intervention. RESULTS: A total of 11,676 patients met inclusion criteria, including 1355 (11.6%) with moderate IMR and 390 (3.3%) with severe IMR. The proportion of patients undergoing mitral intervention for moderate IMR decreased over time (2011, 17.7%; 2020, 7.5%; Ptrend = .001), whereas mitral replacement for severe IMR remained stable (2011, 11.1%; 2020, 13.3%; Ptrend = .14). Major morbidity was higher for patients with moderate IMR who underwent mitral intervention (29.1% vs 19.9%; P = .005). In a propensity analysis of 249 well-matched pairs, there was no difference in major morbidity (29.3% with mitral intervention vs 23.7% without; P = .16) or operative mortality (1.2% vs 2.4%; P = .5). CONCLUSIONS: Consistent with recent guideline updates, patients with moderate IMR were less likely to undergo mitral repair. However, the rate of replacement for severe IMR did not change. Mitral intervention during CABG did not increase operative mortality or morbidity.

Determining optimal donor heart ischemic times in adult cardiac transplantation.

OBJECTIVES: Unsupervised statistical determination of optimal allograft ischemic time (IT) on heart transplant outcomes among ABO donor heart types. METHODS: We identified 36,145 heart transplants (2000-2018) from the United Network for Organ Sharing database. Continuous and categorical variables were analyzed with parametric and nonparametric testing. Determination of IT cutoffs for survival analysis was performed using Contal and O'Quigley univariable method and Vito Muggeo multivariable segmented modeling. RESULTS: Univariable and multivariable IT threshold determination revealed a cutoff at about 3 h. The hourly increase in survival risk with ≥3 h IT is asymmetrically experienced at the early 90 days (hazard ratio [HR] = 1.29, p < .001) and up to 1-year time point (HR = 1.16, p < .001). Beyond 1 year the risk of prolonged IT is less impactful (HR = 1.04, p = .022). Longer IT was associated with more postoperative complications such as stroke (2.7% vs. 2.3, p = .042), dialysis (11.6% vs. 9.1%, p < .001) and death from primary graft dysfunction (1.8% vs. 1.2%, p < .001). O blood type donor hearts with IT ≥ 3 h has significantly increased hourly mortality risk at 90 days (HR = 1.27, p < .001), 90 days to 1 year (HR = 1.22, p < .001) and >1 year (HR = 1.05, p = .041). For non-O blood types with ≥3 h IT hourly mortality risk was increased at 90 days (HR = 1.33, p < .001), but not at 90 days to 1 year (HR = 1.09, p = .146) nor ≥1 year (HR = 1.08, p = .237). CONCLUSIONS: The donor heart IT threshold for survival determined from unbiased statistical modeling occurs at 3 h. With longer preservation times, transplantation with O donor hearts was associated with worse survival.

Outcomes After Prolonged ICU Stays in Postoperative Cardiac Surgery Patients.

Background: Prolonged postoperative intensive care unit (ICU) stays are common after cardiac surgery and are associated with poor outcomes. There are few studies evaluating how risk factors associated with mortality may change during prolonged ICU stays or how mortality may vary with length of stay. We evaluated operative and long-term mortality in post-cardiac surgery patients after prolonged ICU stays at 7, 14, 21, and 28 days and factors associated with mortality. Methods: We included University of Michigan Medical Center cardiac surgery patients with ≥ 7 postoperative days in the ICU. We determined factors associated with hospital mortality at 7, 14, 21, and 28 days of ICU stay using logistic regression, and among hospital survivors, we determined the factors associated with long-term mortality using Cox regression. Results: Of 8309 ICU admissions from cardiac surgery, 1174 (14%) had ICU stays > 7 days. Operative mortality was 11%, 18%, 22%, and 35% for the 7-, 14-, 21-, and 28-day groups, respectively. Mechanical ventilation on the day of assessment was associated with increased odds ratios of operative mortality in all models. Of the 1049 (89%) hospital survivors, 420 (40%) died by late follow-up. Median (IQR) Cox model survival was 10.7 (0.7) years. Longer ICU stays, postoperative pneumonia, and elevated discharge blood urea nitrogen were associated with increased hazard of dying; whereas higher discharge platelet count and cardiac transplant were protective. Conclusions: Both operative and late mortality increased as the duration of a ICU stay increased after cardiac surgery.

Impact of donor blood type on outcomes after prolonged allograft ischemic times.

OBJECTIVE: The study objective was to determine the influence of allograft ischemic time on heart transplant outcomes among ABO donor organ types given limited prior reports of its survival impact. METHODS: We identified 32,454 heart transplants (2000-2016) from the United Network for Organ Sharing database. Continuous and categoric variables were analyzed by parametric and nonparametric testing. Survival was determined using log-rank or Cox regression tests. Propensity matching adjusted for preoperative variables. RESULTS: By comparing allograft ischemic time less than 4 hours (n = 6579) with 4 hours or more (n = 25,875), the hazard ratios for death at 15 years after prolonged ischemic time (≥4 hours) for blood types O, A, B, and AB were 1.106 (P < .001), 1.062 (P < .001), 1.059 (P = .062), and 1.114 (P = .221), respectively. Unadjusted data demonstrated higher mortality for transplantation of O versus non-O donor hearts for ischemic time 4 hours or more (hazard ratio, 1.164; P < .001). After propensity matching, O donor hearts continued to have worse survival if preserved for 4 hours or more (hazard ratio, 1.137, P = .008), but not if ischemic time was less than 4 hours (hazard ratio, 1.042, P = .113). In a matched group with 4 hours or more of ischemic time, patients receiving O donor organs were more likely to experience death from primary graft dysfunction (2.5% vs 1.7%, P = .052) and chronic allograft rejection (1.9% vs 1.1%, P = .021). No difference in death from primary graft dysfunction or chronic allograft rejection was seen with less than 4 hours of ischemic time (P > .150). CONCLUSIONS: Compared with non-O donor hearts, transplantation with O donor hearts with ischemic time 4 hours or more leads to worse survival, with higher rates of primary graft dysfunction and chronic rejection. Caution should be practiced when considering donor hearts with the O blood type when anticipating extended cold ischemic times.

Twenty-four-hour normothermic perfusion of isolated ex vivo hearts using plasma exchange.

OBJECTIVE: Cross-circulation of plasma from a paracorporeal animal allows successful ex vivo heart perfusion (EVHP) for 3 days. Little is known about the feasibility of prolonged EVHP without a paracorporeal animal. These experiments evaluated plasma exchange (PX) that infuses fresh plasma, whereas an equal amount is removed to replace paracorporeal cross-circulation. METHODS: Ten hearts were procured from 8 to 10 kg piglets and maintained with EVHP. The EVHP circuit was primed with platelet- and leukocyte-reduced blood. Plasma obtained from stored porcine blood (4°C for ≤7 days) was infused and removed with a plasma separator at 1 mL/h/g cardiac tissue (n = 5) in the PX group. Controls (n = 5) used the same EVHP without PX. Antegrade aortic perfusion was adjusted to reach physiologic coronary flow of 0.7 to 1.2 mL/min/g, normothermia (37°C), and hemoglobin ≥8 g/dL. Viability was assessed by hemodynamic metrics, metabolic assays, and histopathology. RESULTS: All PX hearts remained viable for 24 hours compared with only 1 control (P = .015). Coronary resistance was higher in the PX versus controls (1.06 ± 0.06 mm Hg/mL/min; 0.58 ± 0.02 mm Hg/mL/min [P < .05]). Lactate levels were lower in PX (2.8-4.2 mmol/L) versus controls (3.6-7.6 mmol/L) (P < .05). PX demonstrated a trend toward preservation of left ventricle systolic pressure (63.0 ± 10.9 mm Hg) versus controls (37 ± 22.0 mm Hg) (P > .05). In mixed effect models, oxygen consumption was higher with PX (P < .05). Histopathologic evaluation confirmed extensive myocardial degeneration and worse interstitial edema in controls. CONCLUSIONS: These results demonstrate that EVHP can be successfully maintained for at least 24 hours using continuous PX. This eliminates the need for a paracorporeal animal and provides an important step toward clinical application.

Pulmonary Endarterectomy for Chronic Thromboembolic Pulmonary Hypertension: An STS Database Analysis.

BACKGROUND: Chronic thromboembolic pulmonary hypertension is optimally treated by pulmonary thromboendarterectomy (PEA). Treatment effectiveness has been evaluated principally using single-center series. Data from The Society of Thoracic Surgeons Adult Cardiac Surgery Database were used to evaluate a volume-outcomes relationship for PEA. METHODS: Circulatory arrest procedures performed between 2012 and 2018 were identified through a Society of Thoracic Surgeons Adult Cardiac Surgery Database Participant User File. For descriptive purposes, total center procedural volume categories were computed: low (0-75th percentile, <16); medium (76-95th percentile, 16-100); high (>95th percentile, >100). Mixed effect modeling was used to evaluate the effect of center procedural volume (modeled continuously) on operative mortality, adjusting for preoperative risk factors, with centers as a random effect. RESULTS: There were 1358 cases performed across 64 centers (low volume: n = 49 of 172; medium volume: n = 12 of 527; high volume: n = 3 of 659), with 42 centers performing less than 10 operations during the period. Procedural volume increased 2.6-fold between 2012 and 2018 (94 vs 339), with 79% of the change in volume accounted for by 4 centers. The median preoperative pulmonary artery systolic value was 74 (interquartile range, 57-88) mm Hg, with no difference (P = .55) by center volume categories. In unadjusted analysis, patients at high-volume centers required fewer transfusions, had shorter ventilator and intensive care unit duration, had a lower frequency of postoperative extracorporeal membrane oxygenation, and trended toward lower mortality (2.1% vs 5.2%; P = .051). Operative mortality was lower at higher-volume centers (adjusted odds ratio [1-case increase], 0.997; 95% confidence interval, 0.994-1.0; P = .025). CONCLUSIONS: Most PEA procedures are performed among a small number of centers, with high-volume hospitals having favorable outcomes. These data suggest a potential role for PEA regionalization.

Human factors in ECLS - A keystone for safety and quality - A narrative review for ECLS providers.

INTRODUCTION: Although the technology used for extracorporeal life support (ECLS) has improved greatly in recent years, the application of these devices to the patient is quite complex and requires extensive training of team members both individually and together. Human factors is an area that addresses the activities, contexts, environments, and tools which interact with human behavior in determining overall system performance. HYPOTHESIS: Analyses of the cognitive behavior of ECLS teams and individual members of these teams with respect to the occurrence of human errors may identify additional opportunities to enhance safety in delivery of ECLS. RESULTS: The aim of this article is to support health-care practitioners who perform ECLS, or who are starting an ECLS program, by establishing standards for the safe and efficient use of ECLS with a focus on human factor issues. Other key concepts include the importance of ECLS team leadership and management, as well as controlling the environment and the system to optimize patient care. CONCLUSION: Expertise from other industries is extrapolated to improve patient safety through the application of simulation training to reduce error propagation and improve outcomes.

Risk factors for heart transplant survival with greater than 5 h of donor heart ischemic time.

OBJECTIVE: Implantation of donor hearts with prolonged ischemic times is associated with worse survival. We sought to identify risk factors that modulate the effects of prolonged preservation. METHODS: Retrospective review of the United Network for Organ Sharing database (2000-2018) to identify transplants with >5 (n = 1526) or ≤5 h (n = 35,733) of donor heart preservation. In transplanted hearts preserved for >5 h, Cox-proportional hazards identify modifiers for survival. RESULTS: Compared to ≤5 h, transplanted patients with >5 h of preservation spent less time in status 1B (76 ± 160 vs. 85 ± 173 days, p = .027), more commonly had ischemic cardiomyopathy (42.3% vs. 38.3%, p = .002), and less commonly received a blood type O heart (45.4% vs. 50.8%, p < .001). Longer heart preservation time was associated with a higher incidence of postoperative stroke (4.5% vs. 2.5%, p < .001), and dialysis (16.4% vs. 10.6%, p < .001). Prolonged preservation was associated with a greater likelihood of death from primary graft dysfunction (2.8% vs. 1.5%, p < .001) but there was no difference in death from acute (2.0% vs. 1.7%, p = .402) or chronic rejection (2.0% vs. 1.9%, p = .618). In transplanted patients with >5 h of heart preservation, multivariable analysis identified greater mortality with ischemic cardiomyopathy etiology (hazard ratio [HR] = 1.36, p < 0.01), pre-transplant dialysis (HR = 1.84, p < .01), pre-transplant extracorporeal membrane oxygenation (ECMO, HR = 2.36, p = .09), and O blood type donor hearts (HR = 1.35, p < .01). CONCLUSION: Preservation time >5 h is associated with worse survival. This mortality risk is further amplified by preoperative dialysis and ECMO, ischemic cardiomyopathy etiology, and use of O blood type donor hearts.

Venoarterial Extracorporeal Membrane Oxygenation for Postcardiotomy Shock-Analysis of the Extracorporeal Life Support Organization Registry.

OBJECTIVES: Refractory postcardiotomy cardiogenic shock complicating cardiac surgery yields nearly 100% mortality when untreated. Use of venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock has increased worldwide recently. The aim of the current analysis was to outline the trends in use, changing patient profiles, and in-hospital outcomes including complications in patients undergoing venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock. DESIGN: Analysis of extracorporeal life support organization registry from January 2010 to December 2018. SETTING: Multicenter worldwide registry. PATIENTS: Seven-thousand one-hundred eighty-five patients supported with venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock. INTERVENTIONS: Venoarterial extracorporeal membrane oxygenation. MEASUREMENTS AND MAIN RESULTS: Hospital death, weaning from extracorporeal membrane oxygenation, hospital complications. Mortality predictors were assessed by multivariable logistic regression. Propensity score matching was performed for comparison of peripheral and central cannulation for extracorporeal membrane oxygenation. A significant trend toward more extracorporeal membrane oxygenation use in recent years (coefficient, 0.009; p < 0.001) was found. Mean age was 56.3 ± 14.9 years and significantly increased over time (coefficient, 0.513; p < 0.001). Most commonly, venoarterial extracorporeal membrane oxygenation was instituted after coronary artery bypass surgery (26.8%) and valvular surgery (25.6%), followed by heart transplantation (20.7%). Overall, successful extracorporeal membrane oxygenation weaning was possible in 4,520 cases (56.4%), and survival to hospital discharge was achieved in 41.7% of cases. In-hospital mortality rates remained constant over time (coefficient, -8.775; p = 0.682), whereas complication rates were significantly reduced (coefficient, -0.009; p = 0.003). Higher mortality was observed after coronary artery bypass surgery (65.4%), combined coronary artery bypass surgery with valve (68.4%), and aortic (69.6%) procedures than other indications. Lower mortality rates were observed in heart transplantation recipients (46.0%). Age (p < 0.001), central cannulation (p < 0.001), and occurrence of complications while on extracorporeal membrane oxygenation were independently associated with poorer prognosis. CONCLUSIONS: The analysis confirmed increased use of venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock. Mortality rates remained relatively constant over time despite a decrease in complications, in the setting of supporting older patients.

Fate of preoperative moderate mitral regurgitation following left ventricular assist device implantation.

OBJECTIVE: We examined for improvements in preoperative moderate mitral regurgitation following continuous-flow left ventricular assist device (cfLVAD) implantation. METHODS: From 2006 to 2020, 190 patients with moderate MR underwent cfVLAD implant without concomitant mitral valve (MV) surgery. Cardiac dimensions and contractility, as well as valve function, were assessed with an echocardiogram (echo) pre-cfLVAD, and at approximately 1 month post-cfLVAD. Outcomes were determined by retrospective chart review. RESULTS: Median echo follow-up was 0.94 (0.53, 1.38) months. Residual significant moderate or greater MR was present in 30/190 (15.8%) on follow-up. Patients with significant residual MR had larger preoperative left ventricular internal diameters in diastole (74.4 ± 8.7 vs. 71.1.0 ± 9.1 mm, p = .034). Significant residual MR was associated with higher preoperative mean pulmonary artery pressures (OR = 1.055, p = .035) and pulmonary capillary wedge pressures (OR = 1.060, p = .034). Significant residual MR on echo was not associated with any survival difference (p = .325). The 1, 5, and 10 year survival were 89.9%, 55.2%, and 34.2%, respectively. CONCLUSIONS: For patients with moderate MR undergoing LVAD implantation, the likelihood of significant residual MR is low and mitral intervention in this population is not recommended. However, select patients with larger preoperative left heart dimensions and pulmonary vascular pressures may be at risk for persistent residual MR.