Cerebral protection strategies for type A aortic dissection repair.

Importance: Techniques to preserve neurological function during type A aortic dissection repairs have been broadly discussed in the literature and heavily debated. Despite the effectiveness of various approaches, a consensus lacks on how to maintain optimal cerebral temperature during surgery. This review examines the three predominant cerebral protection strategies in aortic arch reconstructions: straight deep hypothermic circulatory arrest (sDHCA), retrograde cerebral perfusion (RCP), and antegrade cerebral perfusion (ACP). Observations: The signature characteristics of sDHCA, RCP, and ACP are similar-hypothermia, with or without cerebral perfusion. Employing cerebral perfusion techniques may prolong operative times, while ACP permits operation at higher body temperatures, albeit with restricted operative durations. Conclusion: For type A dissection arch reconstructions, sDHCA, RCP, and ACP can be successfully implemented. Factors such as operative times and individual patient conditions should be considered when choosing a cerebral protection strategy.

Recipient-surgeon racial concordance in orthotopic heart transplantation outcomes.

BACKGROUND: Prior studies have demonstrated deleterious outcomes for physician-patient racial discordance. We explored recipient-surgeon racial concordance and short-term postoperative survival in adults undergoing orthotopic heart transplantation (OHT). METHODS: The United Network for Organ Sharing (UNOS) database was queried to identify White and Black adult (≥18 years) patients undergoing isolated OHT between 2000 and 2020. Surgeon race was obtained from publicly available images. All non-White and non-Black recipients and surgeons were excluded. Linear probability models were utilized to explore the relationship between recipient-surgeon racial concordance and 30-, 60-, and 90-day post-transplant mortality using a fixed effects approach. RESULTS: A total of 26,133 recipients were identified (mean age 52.79 years, 74.4% male) with 77.65% (n = 20,292) being White and 22.35% (n = 5841) being Black. A total of 662 White surgeons performed 25,946 (97.56%) OHTs during the study period while 17 Black surgeons performed 437 (1.67%) OHTs. Although some evidence of differences across groups was observed in cross-tabular specifications, these differences became insignificant after the inclusion of controls (i.e., comorbidities and fixed effects). This suggests that recipient race and physician race are not correlated with post-OHT survival at 30, 60, or 90 days. CONCLUSIONS: Recipient-surgeon racial concordance and discordance among adults undergoing OHT do not appear to impact post-transplant survival. Nor do we observe significant penalties accruing for Black patients overall once controls are accounted for. Given that worse outcomes have historically been demonstrated for Black patients undergoing OHT, further work will be necessary to improve understanding of racial disparities for patients with end-stage heart failure.

Diversity in the Adult and Pediatric Heart Transplant Surgeon Workforce between 2000 and 2020.

There is a paucity of literature evaluating trends in the demographic composition of the cardiothoracic surgery workforce. Using the United Network for Organ Sharing database, we retrospectively analyzed the changes in sex, race, and ethnicity of surgeons performing heart transplantations between 2000−2020. Surgeons performing heart transplantations for adult (≥18 years) and pediatric (<18 years) patients between 2000−2020 were identified and stratified by sex (male, female) and by race/ethnicity (non-Hispanic White, non-Hispanic Black, non-Hispanic Asian, Hispanic of any race). Between 2000−2020, the proportion of non-White and female cardiothoracic surgeons performing adult and pediatric heart transplantations increased. Nevertheless, there remains a lack of diversity in the workforce, particularly when compared to the general United States population.

Ross Operation in Neonates: A Meta-analysis.

BACKGROUND: The Ross operation is the preferred treatment for aortic valve replacement in children. However previous studies indicate that outcomes in neonates are poor. This meta-analysis examines the pooled outcomes of the Ross operation in neonates. METHODS: Four major databases (PubMed/MEDLINE, EMBASE, Scopus, and ScienceDirect) were searched from inception until May 1, 2020 for studies describing outcomes of the Ross operation in neonates. The primary outcome was early mortality, and secondary outcomes were late mortality and mechanical support. Random-effects models were used to account for possible heterogeneity between studies, and continuity corrections were used to include zero total event trials. RESULTS: Eighteen studies comprising outcomes data on 181 neonates were included in the analysis. Meta-analysis showed a pooled early mortality rate of 24% (95% confidence interval, 12%-38%; I2 = 52%, P for heterogeneity = .01). Meta-regression analysis showed that more recently published studies reported significantly worse early mortality (P = .03). The pooled incidence of postoperative mechanical support was 15% (95% confidence interval, 5%-28%; I2 = 28%, P for heterogeneity = .22). No evidence of publication bias was found according to Egger's test (bias coefficient = 0.21, P = .57). CONCLUSIONS: The neonatal Ross operation carries a high early mortality rate. The treatment of unrepairable aortic valves in neonates remains an unsolved problem in congenital cardiac surgery.

Aortic root replacement with bicuspid valve reimplantation: Are outcomes and valve durability comparable to those of tricuspid valve reimplantation?

OBJECTIVES: To assess intermediate-term outcomes of aortic root replacement with valve-sparing reimplantation of bicuspid aortic valves (BAV), compared with tricuspid aortic valves (TAV). METHODS: From January 2002 to July 2017, 92 adults underwent aortic root replacement with BAV reimplantation and 515 with TAV reimplantation at the Cleveland Clinic. Balancing-score matching based on 28 preoperative variables yielded 71 well-matched BAV and TAV pairs (77% of possible pairs) for comparison of postoperative mortality and morbidity, longitudinal echocardiogram data, aortic valve reoperation, and survival. RESULTS: In the BAV group, 1 hospital death occurred (1.1%); mortality among all reimplantations was 0.2%. Among matched patients, procedural morbidity was low and similar between BAV and TAV groups (1 stroke in TAV group; renal failure requiring dialysis, 1 patient each; red cell transfusion, 25% each). Five-year results: Severe aortic regurgitation was present in 7.4% of the BAV group and 2.9% of the TAV group (P = .7); 39% of BAV and 65% of TAV patients had none. Higher mean gradients (10 vs 7.4 mm Hg; P = .001) and left ventricular mass index (111 vs 101 g/m2; P = .5) were present in BAV patients. Freedom from aortic valve reoperation was 94% in the BAV group and 98% in the TAV group (P = .10), and survival was 100% and 95%, respectively (P = .07). CONCLUSIONS: Both BAV and TAV reimplantations can be performed with equal safety and good midterm outcomes; however, the constellation of higher gradients, less ventricular reverse remodeling, and more aortic valve reoperations with BAV reimplantations raises concerns requiring continued long-term surveillance.

Postoperative Outcomes in Infants Undergoing ABO-incompatible Heart Transplantation in the United States.

BACKGROUND: ABO-incompatible heart transplant is a method to increase the infant donor pool. However data on long-term survival and rejection after ABO-incompatible heart transplant in recent era are limited. METHODS: The United Network for Organ Sharing database was queried for infant heart transplants performed from January 2008 to March 2020. Patient demographics and known risk factors for posttransplant mortality were collected. Statistical analysis using Bayesian additive regression trees was performed to evaluate the association of ABO incompatibility and overall survival, graft survival, acute rejection episodes, and length of stay. RESULTS: Of 1368 included infants (age < 1 year), 280 (20.47%) were ABO incompatible. ABO incompatibility was not associated with increased all-cause mortality, acute rejection episodes, or length of stay, whereas extracorporeal membrane oxygenation and intubation status of the recipient at the time of transplantation were associated with increased all-cause mortality and graft failure. Idiopathic cardiomyopathy was associated with a decreased likelihood of posttransplant all-cause mortality. One-, 5-, and 10-year survival rates among compatible vs incompatible transplants were estimated to be 90% vs 88%, 82% vs 79%, and 77% vs 73%, respectively. CONCLUSIONS: ABO-incompatible infant heart transplant does not affect posttransplant survival, incidence of rejection, or postoperative length of stay. Therefore it remains a viable and important strategy to increase the infant donor pool.

Guidelines for the management of thoracic aortic disease in 2017.

This review provides a general overview of the consensus statement from the 2010 more recent updates AHA/ACC Guidelines for the Diagnosis and Management of Patients with Thoracic Aortic Disease, and highlights current practice patterns. The suggestions herein are intended to facilitate clinical decision making in the management of thoracic aortic disease. The main intent of this report is to highlight screening, surveillance, initial and definitive management of thoracic aortic disease, and special populations that should be considered.

Outcomes after mechanical aortic valve replacement in children and young adults with congenital heart disease.

OBJECTIVES: There are little recent data on the outcomes of mechanical aortic valve replacement (AVR) in children and young adults with congenital aortic valve disease. We sought to review the survival and associated thromboembolic or bleeding complications after mechanical AVR at a single center. METHODS: Data were retrospectively collected for 121 patients undergoing prosthetic AVR from 2000 to 2014. Kaplan-Meier estimates and Cox proportional hazards were employed. RESULTS: Median age at AVR was 16 years (interquartile range, 12-22.8 years). The valves implanted were the St Jude valve (St Jude Medical Inc, St Paul, Minn) in 79 patients (62%), the On-X valve (On-X Life Technologies Inc, Austin, Tex) in 45 patients (35%), and CarboMedics (Sorin SpA, Milan, Italy) in 3 patients (2.4%). Median valve size was 23 mm (range, 21-25 mm). There were 5 early deaths (3.9%). Median follow-up was 5 years (range, 1.6-9.2 years; 600 patient-years). There were 14 deaths during follow-up. Survival was 90.6% ± 2.8% at 1 year, 85.4% ± 3.7% at 5 years, and 81.5% ± 4.5% at 10 years. Freedom from aortic valve reoperation was 98% ± 1.4% at 1 and 5 years, 91.5% ± 3.9% at 7 years, and 78.4% ± 6.9% at 10 years and at latest follow-up. Univariable analysis identified younger age, lower weight, and use of a 16-mm CarboMedics valve as predictors of reoperation. Valve sizes of 16 or 17 mm have a significantly higher risk of reoperation compared with larger valves (log-rank test, P < .001). At multivariable analysis, only younger age was a significant independent predictor of reoperation (hazard ratio, 0.84; 95% confidence interval, 0.71-0.99; P = .038). All patients were treated with warfarin to a goal international normalized ratio of 2.0 to 3.0. Four patients (3.1%; 0.66% per patient-year) had thromboembolic complications, and 5 patients (3.9%; 0.83% per patient-year) had bleeding events during follow-up. CONCLUSIONS: Mechanical AVR in patients with congenital heart disease has excellent short- and midterm outcomes. Younger age was an independent predictor of reoperation.

Outcomes and Short-Term Follow-Up in Complex Ross Operations in Pediatric Patients Undergoing Damus-Kaye-Stansel Takedown.

Review echocardiography and outcomes before and after Ross procedures, including patients undergoing biventricular conversion with Damus-Kaye-Stansel (DKS) takedown. A retrospective review was performed on 62 patients undergoing simple (control group) and complex Ross procedures, including 12 patients who underwent biventricular conversion with Ross operation and DKS takedown (complex). Echocardiography was reviewed preoperatively and at discharge and late follow-up. Kaplan-Meier estimates of patient survival and freedom from reintervention were obtained. In all, 62 patients had a median age of 4.5 years (interquartile range [IQR]: 1-12.5), weight of 16.4kg (IQR: 8-41), and follow-up of 3.8 years (IQR: 1.3-6). The complex DKS takedown group had 2 deaths, no neoaortic valve or root reinterventions, and 3 right ventricular outflow tract (VOT) reinterventions. There were no differences from the control group in left VOT or right VOT reinterventions. Neither group showed differences between pre- and late follow-up aortic root and ascending aorta dimensions, and no correlations were found among preoperative pulmonary valve (PV) size, late aortic regurgitation (AR), aortic root, or ascending aortic Z-scores. Aortic valve size increased from discharge to late follow-up for both groups (P ≤ .05); 90% of patients at late follow-up had mild or less AR with similar distributions in severity between complex and control groups. Severity of late AR showed no correlation with preoperative PV size and is independent of it. The Ross procedure has good short-term results in simple and complex patients and should be considered in those undergoing Ross operation with biventricular conversion and DKS takedown. Moreover, native PV size should not be a contraindication for Ross procedure.

Extracorporeal membrane oxygenation support after Ivor-Lewis esophagectomy for esophageal adenocarcinoma.

Respiratory failure after Ivor-Lewis esophagectomy results in poor outcomes. Limited treatment strategies are available to manage this severe complication. One possibility is extracorporeal support. We report the successful use of extracorporeal support as a successful strategy for refractory respiratory failure.

Optimized ventricular restraint therapy: adjustable restraint is superior to standard restraint in an ovine model of ischemic cardiomyopathy.

OBJECTIVE: The effects of ventricular restraint level on left ventricular reverse remodeling are not known. We hypothesized that restraint level affects the degree of reverse remodeling and that restraint applied in an adjustable manner is superior to standard, nonadjustable restraint. METHODS: This study was performed in 2 parts using a model of chronic heart failure in the sheep. In part I, restraint was applied at control (0 mm Hg, n = 3), low (1.5 mm Hg, n = 3), and high (3.0 mm Hg, n = 3) levels with an adjustable and measurable ventricular restraint (AMVR) device. Restraint level was not altered throughout the 2-month treatment period. Serial restraint level measurements and transthoracic echocardiography were performed. In part II, restraint was applied with the AMVR device set at 3.0 mm Hg (n = 6) and adjusted periodically to maintain that level. This was compared with restraint applied in a standard, nonadjustable manner using a mesh wrap (n = 6). All subjects were followed up for 2 months with serial magnetic resonance imaging. RESULTS: In part I, there was greater and earlier reverse remodeling in the high restraint group. In both groups, the rate of reverse remodeling peaked and then declined as the measured restraint level decreased with progression of reverse remodeling. In part II, adjustable restraint resulted in greater reverse remodeling than standard restraint. Left ventricular end diastolic volume decreased by 12.7% (P = .005) with adjustable restraint and by 5.7% (P = .032) with standard restraint. Left ventricular ejection fraction increased by 18.9% (P = .014) and 14.4% (P < .001) with adjustable and standard restraint, respectively. CONCLUSIONS: Restraint level affects the rate and degree of reverse remodeling and is an important determinant of therapy efficacy. Adjustable restraint is more effective than nonadjustable restraint in promoting reverse remodeling.

Restraint to the left ventricle alone is superior to standard restraint.

OBJECTIVE: In standard ventricular restraint therapy, a single level of restraint is applied to the entire ventricular surface. We showed previously that at high restraint levels, cardiac tamponade develops because of the thin-walled right ventricle, even while the left ventricle remains unaffected. We now hypothesize that applying restraint exclusively to the left ventricle permits higher levels of restraint, resulting in increased benefit to the left ventricle. METHODS: The acute effect of restraint applied to the left ventricle alone was analyzed in healthy and cardiomyopathic sheep hearts. Restraint therapy was applied by fluid-filled epicardial balloons placed solely around the left ventricle. Restraint level was defined by the measured balloon luminal pressure at end diastole. At incrementally higher restraint levels (0, 3, 5, 8, 10, 12, and 14 mm Hg), transmural myocardial left ventricular pressure (P(tm) = Left ventricle pressure - Balloon pressure) and indices of myocardial oxygen consumption were measured in healthy sheep (n = 5) and in sheep with heart failure (n = 6). RESULTS: Increasing restraint from 0 to 14 mm Hg decreased transmural myocardial pressure by 48.8% (P ≤ .02) and the left ventricle tension-time index by 39.1% (P ≤ .01), and the pressure-volume area decreased by 58.4% (P ≤ .01). Similarly, stroke work decreased by 57.9% (P ≤ .03). Systemic hemodynamics were unchanged. There was no difference in the trend for all indices between animals that were healthy and those with heart failure. CONCLUSIONS: We showed previously that, with standard restraint, right ventricle tamponade develops at high restraint levels, limiting restraint therapy. We now show that restraint applied to the left ventricle alone permits increased restraint levels, without causing right ventricle or left ventricle tamponade, for greater therapeutic benefit. We conclude that partial left ventricle restraint may be more effective than standard restraint.

Postoperative recurrence of mitral regurgitation after annuloplasty for functional mitral regurgitation.

BACKGROUND: We investigated predictive factors of postoperative recurrence of mitral regurgitation (MR) after mitral valve annuloplasty for functional ischemic MR. METHODS: This study was a retrospective review of patients with functional MR who underwent mitral ring annuloplasty at our institution from 1998 to 2008. Records were reviewed for perioperative variables, including echocardiographic measurements. Recurrence was defined as MR grade moderate (3+) or greater on any postoperative echocardiogram. RESULTS: Of 548 patients who underwent mitral annuloplasty for functional MR, echocardiogram reports were available for review for 250. These patients comprised the study cohort. There were 154 patients with concomitant coronary artery bypass grafting. The left ventricular (LV) end-diastolic (LVED) index was calculated by dividing the LVED dimension by body surface area (BSA). A high LVED index (>3.5 cm/m2) was predictive of MR recurrence (p=0.047): the recurrence rate was 20.3% (13 of 64) in high-index patients and 10.2% (19 of 186) in low-index (<3.5 cm/m2) patients. Median recurrence-free survival was 35 months (range, 19 to 59 months) in high-LVED-index patients and 46.5 months (range, 22 to 75 months) in low-LVED-index patients (p=0.048). Preoperative MR severity and LV ejection fraction were not predictive of MR recurrence. CONCLUSIONS: Careful analysis of the preoperative echocardiogram using a novel, easily calculated variable, the LVED index, may help identify patients who are at greater risk for MR recurrence and reduced survival. Such information could prompt consideration of alternative or additional interventions in these patients.

Past, present, and future of minimally invasive mitral valve surgery.

Minimally invasive mitral valve surgery (mini-MVS) has evolved into a safe and efficient surgical option for many patients. The overall complication rate is reduced, patient satisfaction increased, and hospital costs are lower with this approach, while providing safe and durable surgery. The repair/replacement of mitral valves via a minimally invasive technique represents a significant recent paradigm shift in cardiac surgery. The rapid development and refinement of minimally invasive valve surgery has enabled the repair of complex valves and, most importantly, has yielded similar results to those provided by standard surgical approaches.

Ventricular assist device in patients with prosthetic heart valves.

Ventricular assist device (VAD) support inpatients with a prosthetic heart valve had previously been considered a relative contraindication due to an increased risk of thromboembolic complications. We report our clinical experience of VAD implantation in patients with prosthetic heart valves, including both mechanical and bioprosthetic valves. The clinical records of 133 consecutive patients who underwent VAD implantation at a single institution from January 2002 through June 2009 were retrospectively reviewed. Six of these patients had a prosthetic valve in place at the time of device implantation. Patient demographics,operative characteristics, and postoperative complications were reviewed.Of the six patients,four were male.The mean age was 57.8 years (range 35­66 years). The various prosthetic cardiac valves included a mechanical aortic valve (n = 2), a bioprosthetic aortic valve (n = 3), and a mechanical mitral valve (n = 1).The indications for VAD support included bridge to transplantation (n = 2), bridge to recovery (n = 1), and postcardiotomy ventricular failure(n = 3). Three patients underwent left ventricular assist device placement and three received a right ventricular assist device. Postoperatively, standard anticoagulation management began with a heparin infusion (if possible)followed by oral anticoagulation.The 30-day mortality was50% (3/6). The mean duration of support among survivors was 194.3 days (range 7­369 days) compared with 16.0 days(range 4­29 days) for nonsurvivors. Of the three survivors,two were successfully bridged to heart transplantation and one recovered native ventricular function.Among the three nonsurvivors,acute renal failure developed in each case, and two developed heparin-induced thrombocytopenia. This study suggests that VAD placement in patients with a prosthethic heart valve, either mechanical or bioprosthetic,appears to be a reasonable option.

A novel, innovative ovine model of chronic ischemic cardiomyopathy induced by multiple coronary ligations.

Heart failure is one of the fastest-growing epidemics worldwide in health care today. Although a wide variety of animal models exist to create chronic heart failure, there are few truly successful, reproducible models with ischemic dilation and mitral regurgitation. Six healthy sheep (36 ± 5 kg) underwent multiple, strategic coronary artery ligations on the left ventricle (LV). Six to eight ligations were performed transmurally on three of four segments of the LV: anterior, lateral, and posterior. Side branches of the left anterior descending and circumflex arteries were ligated to create multiple, patchy areas of myocardial infarction. Cardiac global and regional systolic function was assessed by echocardiography and cardiac magnetic resonance imaging (MRI). The extent, the characteristics, and the location of the myocardial infarction were qualitatively and quantitatively assessed by late gadolinium enhancement imaging. The overall mortality rate was 16.7% (1/6 animals). Animals who survived showed a significantly reduced ejection fraction (mean 60 ± 5% to 28 ± 7%; P < 0.05); additionally, two out of the remaining five (40%) animals developed mild to moderate mitral regurgitation quantified by cardiac MRI. Furthermore, each animal developed clinical signs of heart failure (tachycardia, dyspnea, and tachypnea) consistent with global, dilated cardiomyopathy noted on MRI. Creating and reproducing a model of global, ischemic cardiomyopathy with functional mitral regurgitation is an arduous task. We have developed a promising model of ischemic heart failure using multiple ligations, which mimics the sequelae of human cardiomyopathy. Our proposed model is highly effective, reproducible, and may be used for experimental research on heart failure (cardiac assist devices, heart transplant, etc.).

Preventing cardiac remodeling: the combination of cell-based therapy and cardiac support therapy preserves left ventricular function in rodent model of myocardial ischemia.

OBJECTIVE: Cellular and mechanical treatment to prevent heart failure each holds therapeutic promise but together have not been reported yet. The goal of the present study was to determine whether combining a cardiac support device with cell-based therapy could prevent adverse left ventricular remodeling, more than either therapy alone. METHODS: The present study was completed in 2 parts. In the first part, mesenchymal stem cells were isolated from rodent femurs and seeded on a collagen-based scaffold. In the second part, myocardial infarction was induced in 60 rats. The 24 survivors were randomly assigned to 1 of 4 groups: control, stem cell therapy, cardiac support device, and a combination of stem cell therapy and cardiac support device. Left ventricular function was measured with biweekly echocardiography, followed by end-of-life histopathologic analysis at 6 weeks. RESULTS: After myocardial infarction and treatment intervention, the ejection fraction remained preserved (74.9-80.2%) in the combination group at an early point (2 weeks) compared with the control group (66.2-82.8%). By 6 weeks, the combination therapy group had a significantly greater fractional area of change compared with the control group (69.2% ± 6.7% and 49.5% ± 6.1% respectively, P = .03). Also, at 6 weeks, the left ventricular wall thickness was greater in the combination group than in the stem cell therapy alone group (1.79 ± 0.11 and 1.33 ± 0.13, respectively, P = .02). CONCLUSIONS: Combining a cardiac support device with stem cell therapy preserves left ventricular function after myocardial infarction, more than either therapy alone. Furthermore, stem cell delivery using a cardiac support device is a novel delivery approach for cell-based therapies.

Comparison of cardiothoracic surgery training in USA and Germany.

BACKGROUND: Training of cardiothoracic surgeons in Europe and the United States has expanded to incorporate new operative techniques and requirements. The purpose of this study was to compare the current structure of training programs in the United States and Germany. METHODS: We thoroughly reviewed the existing literature with particular focus on the curriculum, salary, board certification and quality of life for cardiothoracic trainees. RESULTS: The United States of America and the Federal Republic of Germany each have different cardiothoracic surgery training programs with specific strengths and weaknesses which are compared and presented in this publication. CONCLUSIONS: The future of cardiothoracic surgery training will become affected by technological, demographic, economic and supply factors. Given current trends in training programs, creating an efficient training system would allow trainees to compete and grow in this constantly changing environment.