Ex vivo heart perfusion: an updated systematic review.

Due to the discrepancy between patients awaiting a heart transplant and the availability of donor hearts, strategies to expand the donor pool and improve the transplant's success are crucial. This review aims to summarize current knowledge on the ex vivo heart preservation (EVHP) experience as an alternative to standard cold static storage (CSS). EVHP techniques can improve the preservation of the donor's heart before transplantation and allow for pre-transplant organ evaluation.

Evaluation of tricuspid valve regurgitation following transvenous rotational mechanical lead extraction.

AIMS: Transvenous lead extraction (TLE) is potentially complicated by significant tricuspid valve regurgitation increase (TRI). However, there are limited data on the effect of the bidirectional rotational mechanical sheaths on significant TRI. The aim of the present study was to investigate the rate of significant changes in tricuspid regurgitation (TR) severity following mechanical rotational TLE and their outcomes. METHODS AND RESULTS: In 158 patients (mean age 66 ± 16.9 years) undergoing mechanical rotational TLE, acute changes in TR severity were assessed by echocardiography evaluation. A significant acute TRI was defined as an increase of at least one grade with a post-extraction severity at least moderate. A total of 290 leads were extracted (mean implant duration, 93 ± 65 months). Significant TRI was noted in 5.7% of patients, and it was linked to tricuspid valve damage, TLE infection indication, and longer lead implant duration. Univariate predictors of significant TRI included implant duration of all leads [odds ratio (OR) 1.01; 95% confidence interval (CI) 1.003-1.018; P = 0.001] and right ventricular leads (OR 1.01; 95% CI 1.004-1.017; P = 0.002). Severe increase of TR following TLE was an independent predictor of mortality [hazard ratio (HR) 5.20; 95% CI 1.44-18.73; P = 0.012 ] along with severe systolic dysfunction (HR 2.37; 95% CI 1.01-5.20; P = 0.032), and systemic infection (HR 2.28; 95% CI 1.06-4.89; P = 0.035). CONCLUSION: Significant TRI was detected in 5.7% of patients following transvenous rotational mechanical lead extraction. The duration of lead implantation emerged as the sole predictor of significant TRI. Physicians engaged in TLE should exercise greater vigilance for this potential complication.

Redefining CAV surveillance strategies: Benefits of CCTA vs. ICA.

BACKGROUND: Cardiac allograft vasculopathy (CAV) assessment post-heart transplantation (HT) typically relies on invasive coronary angiography (ICA). However, cardiac computed tomography angiography (CCTA) is emerging as a promising alternative due to its potential benefits in economic, safety, and logistical aspects. This study aimed to evaluate the impact of a CCTA program on these aspects in CAV surveillance post-HT. METHODS: A retrospective single-center study was conducted between March 2021 and February 2023, involving HT patients who underwent either CCTA or ICA. RESULTS: Among 260 patients undergoing CAV surveillance, 115 (44.2%) patients underwent CCTA, and 145 (55.8%) patients underwent ICA. The CCTA group showed incurred lower overall costs (p â€‹< â€‹0.0001) and shorter hospitalization times (p â€‹< â€‹0.0001) compared to the ICA group. In terms of safety, CCTA surveillance required significantly lower contrast volumes (p â€‹< â€‹0.0001) and lower effective doses (p â€‹= â€‹0.03). CONCLUSION: CCTA emerges as a safe and cost-effective non-invasive alternative for CAV surveillance post-HT, outperforming ICA in terms of safety, logistical aspects, and economic burden.

A Comprehensive Excursus of the Roles of Echocardiography in Heart Transplantation Follow-Up.

Current guidelines for the care of heart transplantation recipients recommend routine endomyocardial biopsy and invasive coronary angiography as the cornerstones in the surveillance for acute rejection (AR) and coronary allograft vasculopathy (CAV). Non-invasive tools, including coronary computed tomography angiography and cardiac magnetic resonance, have been introduced into guidelines without roles of their own as gold standards. These techniques also carry the risk of contrast-related kidney injury. There is a need to explore non-invasive approaches providing valuable information while minimizing risks and allowing their application independently of patient comorbidities. Echocardiographic examination can be performed at bedside, serially repeated, and does not carry the burden of contrast-related kidney injury and procedure-related risk. It provides comprehensive assessment of cardiac morphology and function. Advanced echocardiography techniques, including Doppler tissue imaging and strain imaging, may be sensitive tools for the detection of minor myocardial dysfunction, thus providing insight into early detection of AR and CAV. Stress echocardiography may offer a valuable tool in the detection of CAV, while the assessment of coronary flow reserve can unravel coronary microvascular impairment and add prognostic value to conventional stress echocardiography. The review highlights the role of Doppler echocardiography in heart transplantation follow-up, weighting advantages and limitations of the different techniques.

Impella versus VA-ECMO for the treatment of patients with cardiogenic shock: the Impella Network Project - observational study protocol for cost-effectiveness and budget impact analyses.

INTRODUCTION: The treatment of patients with cardiogenic shock (CS) encompasses several health technologies including Impella pumps and venoarterial extracorporeal membrane oxygenation (VA-ECMO). However, while they are widely used in clinical practice, information on resource use and quality of life (QoL) associated with these devices is scarce. The aim of this study is, therefore, to collect and comparatively assess clinical and socioeconomic data of Impella versus VA-ECMO for the treatment of patients with severe CS, to ultimately conduct both a cost-effectiveness (CEA) and budget impact (BIA) analyses. METHODS AND ANALYSIS: This is a prospective plus retrospective, multicentre study conducted under the scientific coordination of the Center for Research on Health and Social Care Management of SDA Bocconi School of Management and clinical coordination of Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute in Milan. The Impella Network stemmed for the purposes of this study and comprises 17 Italian clinical centres from Northern to Southern Regions in Italy. The Italian network qualifies as a subgroup of the international Impella Cardiac Surgery Registry. Patients with CS treated with Impella pumps (CP, 5.0 or 5.5) will be prospectively recruited, and information on clinical outcomes, resource use and QoL collected. Economic data will be retrospectively matched with data from comparable patients treated with VA-ECMO. Both CEA and BIA will be conducted adopting the societal perspective in Italy. This study will contribute to generate new socioeconomic evidence to inform future coverage decisions. ETHICS AND DISSEMINATION: As of May 2024, most of the clinical centres submitted the documentation to their ethical committee (N=13; 76%), six centres received ethical approval and two centres started to enrol patients. Study results will be published in peer-reviewed publications and disseminated through conference presentations.

Surgery for Active Infective Endocarditis on Mitral Valve: Anatomical, Surgical, and Disease Factors as Long-Term Outcome Modifiers.

Background and Objectives: Determinants of long-term outcomes after surgery for native mitral valve endocarditis have not been thoroughly investigated. The aim of this study was to assess anatomical, disease, and surgical risk factors for long-term mortality and need of reintervention, in patients undergoing mitral valve surgery for active endocarditis. Materials and Methods: Patients who underwent surgery for active native mitral valve endocarditis at three academic centres, between 2000 and 2022, were analysed. The primary outcome was long-term survival. The secondary outcome was the freedom from mitral reoperation. Survival curves were constructed with Kaplan-Meier methodology. Multivariable Cox regression was used to identify demographic, anatomical, disease, and surgical factors associated with late mortality and reoperation. Results: 335 consecutive patients with active mitral endocarditis were analysed. Two hundred and one patients (70.5%) had infection confined to the valve cusp whereas 89 (25.6%) had invasive disease extended to the annulus and surrounding tissues. Preoperative neurological events occurred at the diagnosis in 52 cases. Streptococci were the most common causative organisms followed by Staphylococcus aureus, Coagulase-negative Staphylococcus, and Enterococcus. Valve repair was performed in 108 patients (32.2%). Survival at 5 and 10 years was 70.1% and 59.2%, respectively. Staphylococcus emerged as an independent predictor of late mortality, along with age, chronic obstructive pulmonary disease, and previous cardiac surgery. Survival was considerably reduced in patients with S. aureus compared with those without (log rank p < 0.001). The type of surgery (repair vs. replacement) did not emerge as a risk factor for late mortality and reoperation. Seventeen patients underwent mitral reoperation during the follow-up. The 5- and 10-year freedom from reoperation was 94.7% and 91.8%, respectively. Conclusions: Active mitral valve endocarditis remains a life-threatening disease with impaired survival. While lesion characteristics influenced surgical decision-making and intraoperative management, their impact on long-term survival and freedom from reintervention appears to be moderated by other factors such as infecting pathogens and patient comorbidities.

Successful Recovery of Cardiac Function Following 20 min of a No-touch Period in a Donation After Circulatory Death: A Case Report.

BACKGROUND: Withdrawal of life-sustaining therapy (WLST) performed in the circulatory determination of death (DCD) donors leads to cardiac arrest, challenging the utilization of the myocardium for transplantation. The rapid initiation of normothermic regional perfusion or extracorporeal membrane oxygenation after death helps to optimize organs before implantation. However, additional strategies to mitigate the effects of stress response during WLST, hypoxic/ischemic injury, and reperfusion injury are required to allow myocardium recovery. METHODS: To this aim, our team routinely used a preconditioning protocol for each DCD donation before and during the WLST and after normothermic regional perfusion/extracorporeal membrane oxygenation. The protocol includes pharmacological treatments combined to reduce oxidative stress (melatonin, N -acetylcysteine, and ascorbic acid), improve microcirculation (statins), and mitigate organ's ischemic injury (steroids) and organ ischemia/reperfusion injury (remifentanil and sevoflurane when the heart is available for transplantation). RESULTS: This report presents the first case of recovery of cardiac function, with the only support of normothermic regional reperfusion, following 20 min of a no-touch period and 41 min of functional warm ischemic time in a DCD donor after the preconditioning protocol. CONCLUSIONS: Our protocol seems to be effective in abolishing the stress response during WLST and, on the other hand, particularly organ protective (and heart protective), giving a chance to donate organs less impaired from ischemia/reperfusion injury.

Hybrid Materials for Vascular Applications: A Preliminary In Vitro Assessment.

The production of biomedical devices able to appropriately interact with the biological environment is still a great challenge. Synthetic materials are often employed, but they fail to replicate the biological and functional properties of native tissues, leading to a variety of adverse effects. Several commercial products are based on chemically treated xenogeneic tissues: their principal drawback is due to weak mechanical stability and low durability. Recently, decellularization has been proposed to bypass the drawbacks of both synthetic and biological materials. Acellular materials can integrate with host tissues avoiding/mitigating any foreign body response, but they often lack sufficient patency and impermeability. The present paper investigates an innovative approach to the realization of hybrid materials that combine decellularized bovine pericardium with polycarbonate urethanes. These hybrid materials benefit from the superior biocompatibility of the biological tissue and the mechanical properties of the synthetic polymers. They were assessed from physicochemical, structural, mechanical, and biological points of view; their ability to promote cell growth was also investigated. The decellularized pericardium and the polymer appeared to well adhere to each other, and the two sides were distinguishable. The maximum elongation of hybrid materials was mainly affected by the pericardium, which allows for lower elongation than the polymer; this latter, in turn, influenced the maximum strength achieved. The results confirmed the promising features of hybrid materials for the production of vascular grafts able to be repopulated by circulating cells, thus, improving blood compatibility.

The COVID-19 Pandemic Was Associated with a Change in Therapeutic Management and Mortality in Heart Failure Patients.

Background: Heart failure (HF)-related mortality has been exacerbated by the COVID-19 pandemic; however, it is unclear how healthcare reassessment has contributed to the excess mortality versus SARS-CoV-2 infection itself. We aimed to assess how the pandemic affected the therapeutic management and prognosis of HF patients. Methods: We retrospectively reviewed the healthcare utilization databases of the Lombardy region (Italy) to identify all newly-diagnosed HF patients from January 2018 to December 2021. Outcomes were the utilization of HF therapies (Sacubitril/Valsartan; cardiac resynchronization therapy [CRT] and/or implantable cardioverter-defibrillator [ICD]; mechanical circulatory support [MCS]; heart transplantation [HTX]) and mortality. Cox regression models were fitted to estimate the hazard ratios (HR) and 95% confidence intervals (CI) for outcomes associated with the pandemic. Results: 36,130 and 17,263 patients were identified in the pre-pandemic and pandemic eras, respectively. The pandemic reduced Sacubitril/Valsartan utilization (HR = 0.77, 95% CI: 0.65-0.91) and CRT/ICD implantation (HR = 0.85, 95% CI: 0.78-0.92), but not MCS (HR = 1.11, 95% CI: 0.86-1.43) and HTX (HR = 0.88, 95% CI: 0.70-1.09). An increased mortality risk was observed during the pandemic (HR = 1.19, 95% CI: 1.15-1.23), which was attributable to SARS-CoV-2 infection (HR for non-COVID-19-related mortality = 1.01, 95% CI: 0.97-1.04). Conclusions: The COVID-19 pandemic was associated with a reduction in medical and interventional therapies for HF and an increase in mortality for HF patients.

Six-year clinical and computed tomography angiography follow-up after Nexus implantation.

Endovascular aortic arch repair (Ar-TEVAR) with single-branch, off-the-shelf Nexus aortic arch system has shown promising early and 3-year outcomes. There is lack of data regarding long-term results of this specific device, particularly regarding patency of supra-aortic bypasses and stability of the connection between the 2 modules. This case report describes 6-year clinical and imaging follow-up of a 74-year-old patient who underwent Ar-TEVAR with Nexus. Over 6 years, the patient experienced minor complications unrelated to the device. The patency of supra-aortic bypasses and integrity of the device's connection were confirmed. Computed tomography angiography constantly showed exclusion of the aneurysm and reduction of the aneurysmal sac. In conclusion, although extended research and broader data are needed, this case provides encouraging evidence of long-term results of Ar-TEVAR with Nexus.

Endovascular aortic arch repair under monitored anaesthesia care: maximizing microinvasiveness.

Patients with aortic arch pathologies after surgery for type-A acute aortic dissection represent a challenging population since open surgery is associated with a non-negligible rate of mortality and complications. Microinvasive endovascular aortic arch repair Arch-Thoracic EndoVascular Aortic Repair (Ar-TEVAR) has shown promising results in high-risk patients. Ar-TEVAR is usually performed under general anaesthesia. We report the case of an 83-year-old man with a history of ascending aorta replacement for type-A acute aortic dissection who was referred for an anastomotic pseudoaneurysm. Ar-TEVAR using an off-the-shelf single-branch aortic arch stent graft was chosen. In order to further minimize procedural invasiveness, monitored anaesthesia care (local anaesthesia with sedation and analgesia) was performed since it provides less stress on the cardiovascular and respiratory systems and overall leads to a faster recovery especially in elderly patients.

Overcoming the Boundaries of Heart Warm Ischemia in Donation After Circulatory Death: The Padua Case.

A 45 year old male obese patient with a previous history of repaired congenital heart disease developed worsening heart failure making heart transplantation listing mandatory. Unfortunately, due to his anthropometric measures, the search for a suitable brain-dead donor was unsuccessful. For this reason, he accepted to be enrolled in the controlled donation after circulatory death (cDCD) program. According to the Italian Law regulating death declaration after cardiac arrest (no-touch period of 20 minutes-one of the longest in the world), we faced a 34 minute cardiac asystole, after which the heart was recovered through a thoraco-abdominal normothermic regional perfusion excluding the epiaortic vessels. The heart was then preserved by means of cold static storage. Heart transplantation was performed successfully without any signs of primary graft failure. Postoperative endomyocardial biopsies were negative for acute cellular and antibody-mediated rejection. Furthermore, echocardiographic and cardiac magnetic resonance evaluation of the heart did not show any functional abnormalities. The patient was discharged on post-operative day (POD) #39 in good clinical conditions.

Comparison of 4 mortality scores for surgical repair of type A aortic dissection: a multicentre external validation.

OBJECTIVES: In the last decades, 4 different scores for the prediction of mortality following surgery for type A acute aortic dissection (TAAD) were proposed. We aimed to validate these scores in a large external multicentre cohort. METHODS: We retrospectively analysed patients who underwent surgery for TAAD between 2000 and 2020. Patients were enrolled from 10 centres from 2 European countries. Outcomes were the early (30-day and/or in-hospital) and 1-year mortality. Discrimination, calibration and observed/expected (O/E) ratio were evaluated. RESULTS: A total of 1895 patients (31.7% females, mean age 63.72 ± 12.8 years) were included in the study. Thirty-day mortality and in-hospital mortality were 21.7% (n = 412) and 22.5% (n = 427) respectively. The German Registry of Acute Aortic Dissection Type A (GERAADA) score shows to have the best discrimination [area under the curve (AUC) 0.671 and 0.672] in predicting as well the early and the 1-year mortality, followed by the International Registry of Acute Aortic Dissection (IRAD) model 1 (AUC 0.658 and 0.672), the Centofanti (AUC 0.645 and 0.66) and the UK aortic score (AUC 0.549 and 0.563). According to Hosmer-Lemeshow and Brier tests, the IRAD model I and GERAADA, respectively, were well calibrated for the early mortality, while the GERAADA and Centofanti for the 1-year mortality. The O/E analysis showed a marked underestimation for patients labelled as low-risk for UK aortic score and IRAD model I for both outcomes. CONCLUSIONS: The GERAADA score showed the best performance in comparison with other scores. However, none of them achieved together a fair discrimination and a good calibration for predicting either the early or the 1-year mortality.

Techniques and Technologies to Improve Vein Graft Patency in Coronary Surgery.

Vein grafts are the most used conduits in coronary artery bypass grafting (CABG), even though many studies have suggested their lower patency compared to arterial alternatives. We have reviewed the techniques and technologies that have been investigated over the years with the aim of improving the quality of these conduits. We found that preoperative and postoperative optimal medical therapy and no-touch harvesting techniques have the strongest evidence for optimizing vein graft patency. On the other hand, the use of venous external support, endoscopic harvesting, vein preservation solution and anastomosis, and graft configuration need further investigation. We have also analyzed strategies to treat vein graft failure: when feasible, re-doing the CABG and native vessel primary coronary intervention (PCI) are the best options, followed by percutaneous procedures targeting the failed grafts.

Left ventricular assist device in the presence of subcutaneous implantable cardioverter defibrillator: Data from a multicenter experience.

BACKGROUND: Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure (HF). Subcutaneous implantable cardioverter defibrillator (S-ICD) might be a viable alternative to conventional ICDs with a lower risk of short- and long-term of device-related complications and infections.The aim of this multicenter study was to evaluate the outcomes and management of S-ICD recipients who underwent LVAD implantation. METHODS: The study population included patients with a preexisting S-ICD who underwent LVAD implantation for advanced HF despite optimal medical therapy. RESULTS: The study population included 30 patients (25 male; median age 45 [38-52] years).The HeartMate III was the most common LVAD type. Median follow-up in the setting of concomitant use of S-ICDs and LVADs was 7 months (1-20).There were no reports of inability to interrogate S-ICD systems in this population. Electromagnetic interference (EMI) occurred in 21 (70%) patients. The primary sensing vector was the one most significantly involved in determining EMI. Twenty-seven patients (90%) remained eligible for S-ICD implantation with at least one optimal sensing vector. The remaining 3 patients (10%) were ineligible for S-ICD after attempts of reprogramming of sensing vectors. Six patients (20%) experienced inappropriate shocks (IS) due to EMI. Six patients (20%) experienced appropriate shocks. No S-ICD extraction because of need for antitachycardia pacing, ineffective therapy or infection was reported. CONCLUSIONS: Concomitant use of LVAD and S-ICD is feasible in most patients. However, the potential risk of EMI oversensing, IS and undersensing in the post-operative period following LVAD implantation should be considered. Careful screening for EMI should be performed in all sensing vectors after LVAD implantation.

Transvenous lead extraction of lumenless 3830 pacing lead in conduction system pacing: a single-center experience.

BACKGROUND: The Medtronic SelectSecure Model 3830 lumenless lead (Medtronic, Inc., Minneapolis, MN) is commonly used for conduction system pacing (CSP). However, with this increased use, the potential need for transvenous lead extraction (TLE) also will increase. While extraction of endocardial 3830 leads is rather well described especially in pediatric and adult congenital heart disease population, there is very limited data on extraction of CSP leads. In the present study, we reported our preliminary experience on TLE of CSP leads and provided technical considerations. METHODS: The study population comprised 6 consecutive patients (67% male; mean age 70 ± 22 years) with CSP leads (3830 leads), including left bundle branch pacing (LBBP) lead (n = 3) and His pacing lead (n = 3) undergoing TLE. Overall target leads were 17. The mean implant duration time of CSP leads was 97 ± 90 months [range 8-193). RESULTS: Manual traction was successful in 2 cases and mechanical extraction tools were required in the remaining cases. Sixteen leads (94%) were completely extracted, whereas incomplete removal was observed in one lead (6%) among 1 patient. Of note, in the only lead incompletely removed, we observed retention of < 1-cm remnant of lead material consisting of the screw of 3830 LBBP lead into the interventricular septum. No failure of lead extraction was reported and no major complications occurred. CONCLUSIONS: Our findings demonstrated that at an experienced center the success of TLE of chronically implanted CSP leads is high in the absence of major complications also when mechanical extraction tools are needed.

Optimizing Safety and Success: The Advantages of Bloodless Cardiac Surgery. A Systematic Review and Meta-Analysis of Outcomes in Jehovah's Witnesses.

Transfusions are extremely frequent after cardiac surgery, and they have a considerable economic burden and impact on outcomes. Optimal patient blood management could play a fundamental role in reducing the rate of transfusion and Jehovah's Witnesses (JW) represent the ideal surrogate study population. This meta-analysis compares outcomes of JWs and non-JWs' patients undergoing cardiac surgery, assessing the safety of a bloodless cardiac surgery. A scoping review was conducted using a search strategy for studies assessing outcomes of JW undergoing cardiac surgery. The primary outcome was perioperative mortality, and a random-effects meta-analysis was performed. Ten studies were included in our meta-analysis, involving 780 JW patients refusing any type of transfusion ("JW") and 1182 patients accepting transfusion if needed ("non-JW"). 86% of non-JW patients received at least 1 transfusion. There was no significant difference in terms of perioperative mortality (OR 0.91; 95% CI 0.55-1.52; p = 0.72). The volume blood loss was significantly less in the JW (p = 0.001), while the rate of reoperation for bleeding was also lower, but not statistically significative, in the JW (p = 0.16). Both preoperative and postoperative hemoglobin and hematocrit were significantly higher in the JW. Therefore, we concluded that bloodless cardiac surgery is safe and early outcomes are similar between JW and non-JW patients: optimal patient blood management is fundamental in guarantying these results. Further studies are needed to assess if a limitation of transfusion could have a positive long-term impact on outcomes.

A cardiac intimal sarcoma mimicking infective endocarditis.

Primary malignant cardiac tumors are rare and usually misdiagnosed because they can mimic more common intracardiac lesions, therefore, in clinical practice it is important to always consider even uncommon diseases in order to avoid delayed diagnosis and to plan the most appropriate therapeutic strategy in a timely fashion. We report a case of a 73-year-old man with clinical signs and imaging findings (echocardiography) suggesting infective bacterial endocarditis of the mitral valve. However, intraoperative evaluation raised suspicion that the mitral lesions had a different nature. Surgical removal of the mass was performed, and the final correct diagnosis was made through pathologic examination, revealing a mitral valve sarcoma thus allowing for the beginning of specific oncological treatment.

The introduction of surgical simulation on three-dimensional-printed models in the cardiac surgery curriculum: an experimental project.

AIMS: Training in congenital cardiac surgery has become more and more difficult because of the reduced opportunities for trainees in the operating room and the high patient anatomical variability. The aim of this study was to perform a pilot evaluation of surgical simulation on a simple 3D-printed heart model in training of young surgeons and its potential inclusion in the curriculum of residency programs. METHODS: A group of 11 residents performed a surgical correction of aortic coarctation using a 3D-printed surgical model. After teaching the surgical procedure, a simulation was performed twice, at different times, and was evaluated quantitatively and qualitatively by a senior surgeon. A 3D model-based training program was then developed and incorporated into our cardiac surgery training program. RESULTS: A significant improvement in surgical technique was observed between the first and second surgical simulations: median of 65% [interquartile range (IQR) = 61-70%] vs. 83% (IQR = 82-91%, P < 0.001). The median time required to run the simulation was significantly shorter during the second simulation: 39 min (IQR = 33-40) vs. 45 min (IQR = 37-48; P = 0.02). Regarding the simulation program, a basic and an advanced program were developed, including a total of 40 different simulated procedures divided into 12 sessions. CONCLUSION: Surgical simulation using 3D-printing technology can be an extremely valuable tool to improve surgical training in congenital heart disease. Our pilot study can represent the first step towards the creation of an integrated training system on 3D-printed models of congenital and acquired heart diseases in other Italian residency programs.