Functional Mitral Valve Regurgitation: Mitral Valve Repair or Replacement? Our "Road Map" for the Appropriate Strategy.

Objectives: The optimal surgical approach for the treatment of functional mitral regurgitation (FMR) remains controversial. Current guidelines suggest that the surgical approach has to be tailored to the individual patient. The aim of the present study was to clarify further aspects of this tailored treatment. Methods: From 01/2006 to 12/2015, 390 patients underwent mitral valve (MV) surgery for FMR (ischemic n = 241, non-ischemic n = 149) at our institution. A regression analysis was used to determine the effect of MV repair or replacement on survival. The patients were analyzed according to the etiology of the MR (ischemic or non-ischemic), different age groups (<65 years, 65-75 years, and >75 years), LV function, and LV dimensions, as well as the underlying heart rhythm. Results: The overall survival rates for the repair group at 1, 5, and 8 years were 86.1 ± 1.9%, 70.6 ± 2.6%, and 55.1 ± 3.1%, respectively. For the same intervals, the survival rates in patients who underwent MV replacement were 75.9 ± 4.5%, 58.6 ± 5.4%, and 40.9 ± 6.4%, respectively (p = 0.003). Patients younger than 65 years, with an ischemic etiology of FMR, poor ejection fraction (<30%), severe dilatation of left ventricle (LVEDD > 60mm), and presence of atrial fibrillation had significantly higher mortality rates after MV replacement (HR, 3.0; CI, 1.3-6.9; p = 0.007). Patients between 65 and 75 years of age had a higher risk of death when undergoing mitral valve replacement (HR, 1.7; CI, 1.0-2.8; p = 0.04). In patients older than 75 years, the surgical approach (MV repair or replacement) had no effect on postoperative survival (HR, 0.8; CI, 0.4-1.3; p = 0.003). Conclusions: Our data demonstrate that, in patients younger than 65 years, the treatment of choice for FMR should be MV repair. This advantage was even more evident in patients with an ischemic origin of MR, a poor ejection fraction, a severe LV dilatation, and atrial fibrillation.

Impact of Patient-Prosthesis Mismatch on Long-term Outcomes After Aortic Valve Replacement.

BACKGROUND: Patient-prosthesis mismatch (PPM) after aortic valve replacement potentially affects the outcome after the operation. This study sought to determine whether PPM has an impact on long-term mortality and reoperation rates. METHODS: We included 645 patients who underwent biologic aortic valve replacement between 2000 and 2007. Based on echocardiographic examinations at postoperative month 6, the incidence of PPM was determined according to an indexed effective orifice area <0.85 cm2/m2. Survival and reoperation status were analyzed during 15 years of follow-up. RESULTS: PPM was present in 256 patients (40%), of whom 175 had moderate PPM and 81 had severe PPM. In multivariable adjusted analysis, survival was not statistically significantly impaired in patients with moderate PPM compared with patients with no PPM, whereas patients with severe PPM showed a marginally significant impairment of survival (hazard ratio [HR], 1.40; 95% CI, 0.99-1.97; P = .054). Risk factors for survival were higher age (HR, 1.12; 95% CI, 1.10-1.14; P < .001), arterial hypertension (HR, 1.78; 95% CI, 1.38-2.31; P < .001), and diabetes mellitus (HR, 1.67; 95% CI, 1.31-2.14; P < .001). In patients with no, moderate, and severe PPM, there were 10.1, 8.5, and 14.8 events of reoperation/1000 patient-years, respectively. The corresponding 10-year cumulative incidence of reoperation was 8.3%, 6.7%, and 12.1%, respectively. In multivariable adjusted analysis, PPM category was not significantly associated with the risk of reoperation (P > .2). CONCLUSIONS: In our study with directly measured effective orifice area, PPM was only marginally related to long-term survival and was not statistically significantly associated with the risk of reintervention.

Gender and Sex Differences in the Management, Intervention, and Outcomes of Patients With Severe Primary Mitral Regurgitation.

BACKGROUND: Gender- and sex-based disparities in mitral valve disease exist; however the factors associated with these differences are unknown. Identifying these differences is essential in devising mitigating strategies. We evaluated gender and sex differences among patients with severe primary mitral regurgitation (MR) across treatment phases. METHODS AND RESULTS: We conducted a retrospective cohort study of patients with new diagnoses of severe primary MR between 2016 and 2020. We compared multidisciplinary evaluation incidence and 2-year survival between men and women. We analyzed a subgroup meeting class 1 indications for intervention, which includes severe symptomatic MR or severe asymptomatic MR with ejection fraction <60% or left ventricular end-systolic diameter >40 mm. Logistic regression models identified predictors associated with the likelihood of multidisciplinary evaluation. Among 330 patients meeting class 1 indications, women were older (79 versus 76 years, P=0.01) and had higher Society of Thoracic Surgeons risk scores for mitral valve repair than men (2.5% versus 1.4%, P=0.003). Women were less likely to undergo multidisciplinary evaluation (57% versus 84%, P<0.001) and intervention (47% versus 69%, P<0.001) than men. Median days to intervention for women and men were 77 and 43, respectively. Women had a higher 2-year mortality rate than men (31% versus 21%, P=0.035). On a multivariable model, female sex and older age were associated with lower odds of undergoing multidisciplinary evaluation (odds ratio, 0.26; P<0.001; odds ratio, 0.95; P<0.001, respectively). CONCLUSIONS: Women with severe primary MR with class 1 indication for intervention were less likely to undergo multidisciplinary evaluation and intervention and had a longer interval to intervention than men. Survival was comparable after accounting for age and comorbidity differences.

Midterm results after aortic valve neocuspidization.

Objectives: Aortic valve neocuspidization with autologous pericardium is gaining increasing attention as a surgical treatment option for aortic valve disease. However, little is known about midterm durability and valve-related events. Methods: Patients undergoing aortic valve neocuspidization between 2016 and 2021 were included. Transthoracic echocardiography was performed before the operation, at discharge, and annually thereafter. Data were analyzed for incidences of structural valve deterioration, bioprosthetic valve failure, survival, freedom from reoperation, and hemodynamic performance. Results: A total of 162 patients underwent aortic valve neocuspidization (mean age, 52.6 ± 16.6 years; range, 13-78 years); 114 (70.4%) were male. A total of 132 patients presented with a bicuspid aortic valve (81.5%) and 126 patients presented with aortic valve stenosis (77.8%). Concomitant procedures were performed in 63 patients (38.9%). Mean follow-up was 3.5 ± 1.2 years. At discharge, peak and mean pressure gradients were 15.6 ± 7.2 mm Hg and 8.4 ± 3.7 mm Hg, respectively, with a mean effective orifice area of 2.4 ± 0.8 cm2. After 5 years, peak and mean pressure gradients were 14.5 ± 4.6 mm Hg and 7.5 ± 2.2 mm Hg, respectively, with a mean effective orifice area of 2.3 ± 0.8 cm2. At 5 years, cumulative incidences of moderate and severe structural valve deterioration and bioprosthetic valve failure were 9.82% ± 3.87%, 6.96% ± 3.71%, and 12.1% ± 4.12%, respectively. Survival was 97.3% ± 1.4%, and freedom from reoperation was 91.3% ± 2.4%. Conclusions: Aortic valve neocuspidization accomplishes low pressure gradients early after initial surgery and during follow-up. Survival in this young patient population is excellent. The main reason for reoperation is endocarditis, and rates for structural valve degeneration are low.

The high-risk features among patients undergoing mitral valve operation for ischemic mitral regurgitation: The 3-strike score.

Objective: Ischemic mitral regurgitation is prevalent and associated with high surgical risk. With the less-invasive option of transcatheter edge-to-edge repair, the optimal patient selection for mitral valve operation for ischemic mitral regurgitation remains unclear. We sought to identify high-risk features in this group to guide patient selection. Methods: Using the Cardiothoracic Surgery Trial Network's severe ischemic mitral regurgitation trial data, we identified patient and echocardiographic characteristics associated with an increased risk of 2-year mortality using the support vector classifier and Cox proportional hazards model. We identified 6 high-risk features associated with 2-year survival. Patients were categorized into 3 groups, each having 1 or less, 2, or 3 or more of the 6 identified high-risk features. Results: Among the 251 patients, the median age was 69 (Q1 62, Q3 75) years, and 96 (38%) were female. Two-year mortality was 21% (n = 53). We identified 6 high-risk preoperative features: age 75 years or more (n = 69, 28%), prior sternotomy (n = 49, 20%), renal insufficiency (n = 69, 28%), gastrointestinal bleeding (n = 15, 6%), left ventricular ejection fraction less than 40% (n = 131, 52%), and ventricular end-systolic volume index less than 50 mL/m2 (n = 93, 37%). In patients who had 1 or less, 2, and 3 or more high-risk features, 90-day mortality was 4.2% (n = 5), 9.9% (n = 4), and 20.0% (n = 10), respectively (P = .006), and 2-year mortality was 10% (n = 12), 22% (n = 18), and 46% (n = 23) (P < .001), respectively. Conclusions: We developed the 3-strike score by identifying high-risk preoperative features for mitral valve surgery for ischemic mitral regurgitation. Patients having 3 or more of such high-risk features should undergo careful evaluation for surgical candidacy given the high early and late mortality after mitral valve operations.

The Burden of Obesity in Cardiac Surgery: A 14 years' Follow-Up of 14.754 Patients.

Aims: The prevalence of obesity is rapidly increasing during the past decades. While previous research has focused on the early outcome after cardiac surgery or specific complications, the current study covers the whole burden of obesity in the field of cardiac surgery over short term and long term. Endpoints of the study were all-cause mortality, perioperative outcome, and wound-healing disorders (WHDs). Methods: 14.754 consecutive patients who underwent cardiac surgery over a 14 years' time period were analyzed. BMI classifications were used according to the WHO definition. Results: Mean survival was 11.95 years ± 0.1; CI 95% [12.04-12.14]. After adjustment for clinical baseline characteristics, obesity classes' I-III (obesity) did not affect 30-day mortality or all-cause mortality during the whole observational period. After adjustment for known risk factors, the risk for WHDs doubled at least in obesity patients as follows: obesity I (OR = 2.06; CI 95% [1.7-2.5]; p < 0.0001), obesity II (OR = 2.5; CI 95% [1.83-3.41]; p < 0.0001), and obesity III (OR = 4.12; CI 95% [2.52-6.74]; p < 0.0001). The same applies to the risk for sternal reconstruction that is substantially elevated in obesity I (OR = 2.23; CI 95% [1.75-2.83]; p < 0.0001), obesity II (OR = 2.81; CI 95% [1.91-4.13]; p < 0.0001), and obesity III (OR = 2.31; CI 95% [1.08-4.97]; p=0.03). No significant correlation could be found between obesity and major adverse events in the perioperative course like renal failure, ventilation >24 h, re-exploration, or cerebrovascular events. Conclusions: Cardiac surgery is safe in obesity as short- and long-term mortality are not increased, and major adverse events during the perioperative course are similar to control patients. The burden of obesity lies in substantially increased rates of wound-healing disorders and sternal reconstructions.

Transcatheter or Surgical Treatment of Aortic-Valve Stenosis.

BACKGROUND: Among low-risk patients with severe, symptomatic aortic stenosis who are eligible for both transcatheter aortic-valve implantation (TAVI) and surgical aortic-valve replacement (SAVR), data are lacking on the appropriate treatment strategy in routine clinical practice. METHODS: In this randomized noninferiority trial conducted at 38 sites in Germany, we assigned patients with severe aortic stenosis who were at low or intermediate surgical risk to undergo either TAVI or SAVR. Percutaneous- and surgical-valve prostheses were selected according to operator discretion. The primary outcome was a composite of death from any cause or fatal or nonfatal stroke at 1 year. RESULTS: A total of 1414 patients underwent randomization (701 to the TAVI group and 713 to the SAVR group). The mean (±SD) age of the patients was 74±4 years; 57% were men, and the median Society of Thoracic Surgeons risk score was 1.8% (low surgical risk). The Kaplan-Meier estimate of the primary outcome at 1 year was 5.4% in the TAVI group and 10.0% in the SAVR group (hazard ratio for death or stroke, 0.53; 95% confidence interval [CI], 0.35 to 0.79; P<0.001 for noninferiority). The incidence of death from any cause was 2.6% in the TAVI group and 6.2% in the SAVR group (hazard ratio, 0.43; 95% CI, 0.24 to 0.73); the incidence of stroke was 2.9% and 4.7%, respectively (hazard ratio, 0.61; 95% CI, 0.35 to 1.06). Procedural complications occurred in 1.5% and 1.0% of patients in the TAVI and SAVR groups, respectively. CONCLUSIONS: Among patients with severe aortic stenosis at low or intermediate surgical risk, TAVI was noninferior to SAVR with respect to death from any cause or stroke at 1 year. (Funded by the German Center for Cardiovascular Research and the German Heart Foundation; DEDICATE-DZHK6 ClinicalTrials.gov number, NCT03112980.).

Early outcomes of transapical mitral valve implantation versus surgical replacement in matched elderly patients at intermediate surgical risk.

BACKGROUND: Data comparing transcatheter mitral valve implantation (TMVI) with surgical mitral valve replacement (SMVR) are lacking. AIMS: This study sought to compare the 30-day Valve Academic Research Consortium (VARC)-3 device success of TMVI with that of SMVR. METHODS: Matching protocol combined exact matching (sex, atrial fibrillation, previous surgical aortic valve replacement [SAVR] or coronary artery bypass grafting [CABG]), coarsened exact matching (age) and propensity score matching (body mass index, mitral valve pathology and concomitant tricuspid regurgitation). RESULTS: A total of 40 Tendyne TMVI and 80 SMVR patients with similar baseline characteristics were analysed (TMVI vs SMVR): age (78 years [interquartile range [{IQR} 75; 80] vs 78 years [IQR 73; 80]; p=0.8), female (60% vs 60%; p=1.0), atrial fibrillation (67.5% vs 63.7%; p=0.8), previous SAVR (12.5% vs 10.0%; p=0.8), previous CABG (20.0% vs 16.2%; p=0.8), body mass index (25.54 kg/m² vs 25.24 kg/m²; p=0.7) and valve pathology (mitral regurgitation: 70.0% vs 73.8%, mitral stenosis: 7.5% vs 3.8%, and mixed disease: 22.5% vs 22.5%; p=0.6). Most baseline characteristics not included in the matching model were balanced among the TMVI/SMVR cohorts: European System for Cardiac Operative Risk Evaluation (EuroSCORE) II (5.8% [IQR 2.9; 7.5] vs 4.2% [IQR 2.4; 6.8]; p=0.3) and Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) score (5.2% [IQR 3.2; 8.6] vs 4.1% [IQR 3.3; 6.1]; p=0.076). Coronary artery disease (67.5% vs 32.5%; p<0.001) and previous percutaneous coronary intervention (47.5% vs 25.0%; p=0.023) differed among groups. Mitral VARC (MVARC) device success at 30 days was achieved in 82.5% of patients after TMVI and 57.5% of patients after SMVR (p=0.04). MVARC procedural success at 30 days was 75.0% after TMVI versus 52.5% after SMVR (p=0.07). Thirty-day mortality (2.5% vs 3.8%; p=0.47), technical success (97.5% vs 97.5%; p=1.0), major bleeding (17.5% vs 18.7%; p=0.087), stroke (5.0% vs 4.9%; p=1.0) and postoperative haemodialysis (7.5% vs 5.2%; p=0.4) were similar in both groups. CONCLUSIONS: Patients with intermediate surgical risk, according to STS-PROM and EuroSCORE II, demonstrated higher rates of MVARC device at 30 days after TMVI compared to 30 days after SMVR. Rates of survival and procedural success, neurological, renal and bleeding complications were similar. Transfusion count and length of stay were lower after TMVI. For elderly patients at intermediate risk, a TMVI eligibility assessment may be considered.

Implementing Formal Mitral Heart Team Improves Multidisciplinary Evaluation Rate and Survival of Patients With Severe Primary Mitral Regurgitation.

BACKGROUND: Multidisciplinary heart team (HT) evaluation is recommended for patients with severe primary mitral regurgitation to optimize treatment decisions. However, its impact on patient outcomes remains unknown. We evaluated the impact of implementing mitral HT on patient survival. METHODS AND RESULTS: We conducted a retrospective cohort study of patients with new diagnoses of severe primary mitral regurgitation in a large healthcare network echocardiogram database between 2016 and 2020. We compared the incidence of multidisciplinary evaluation by structural cardiology and cardiac surgery services and 2-year survival before and after mitral HT implementation. The 1:1 propensity-score matching between pre- and post-mitral HT used Society of Thoracic Surgeons Predicted Risk of Mortality for mitral repair, age, sex, race, heart failure symptoms, inpatient setting, history of MI, and dementia as covariates. Logistic regression identified variables associated with the likelihood of undergoing multidisciplinary evaluation. Among 70 510 echocardiograms performed, 391 patients had severe primary mitral regurgitation (median age, 77 years; 46% women). Multidisciplinary evaluation increased from 29% to 89% (P<0.001), and intervention increased from 24% to 75% following mitral HT implementation (P<0.001). Among 180 propensity-score matched patients, mortality was lower post-mitral HT at 2 years (19% versus 32%, P=0.04). The multivariable model showed that mitral HT implementation and heart failure symptoms were associated with higher odds of undergoing multidisciplinary evaluation (OR [odds ratio], 18.7 and 2.72, respectively), whereas female sex and older age were associated with lower odds (OR, 0.39 and 0.93, respectively). CONCLUSIONS: Implementation of mitral HT was associated with drastic improvement in multidisciplinary evaluation for patients with severe primary mitral regurgitation. This coincided with higher proportions of patients undergoing mechanical correction of MR and improved overall patient survival.

Totally endoscopic, robotic-assisted tricuspid valve repair and biatrial CryoMAZE.

We describe in detail our technique for totally endoscopic, robotic-assisted tricuspid valve repair for iatrogenic tricuspid regurgitation and biatrial cryoMAZE.

Robotic Mitral Valve Repair for Degenerative Mitral Regurgitation.

BACKGROUND: Contemporary national utilization and comparative safety data of robotic mitral valve repair for degenerative mitral regurgitation compared with nonrobotic approaches are lacking. The study aimed to characterize national trends of utilization and outcomes of robotic mitral repair of degenerative mitral regurgitation compared with sternotomy and thoracotomy approaches. METHODS: Patients undergoing intended mitral repair of degenerative mitral regurgitation in The Society of Thoracic Surgeons Adult Cardiac Surgery Database between 2015 and 2021 were examined. Mitral repair was performed in 61,322 patients. Descriptive analyses characterized center-level volumes and outcomes. Propensity score matching separately identified 5540 pairs of robotic vs thoracotomy approaches and 6962 pairs of robotic vs sternotomy approaches. Outcomes were operative mortality, composite mortality and major morbidity, postoperative length of stay, and conversion to mitral replacement. RESULTS: Through the 7-year study period, 116 surgeons across 103 hospitals performed mitral repair robotically. The proportion of robotic cases increased from 10.9% (949 of 8712) in 2015 to 14.6% (1274 of 8730) in 2021. In both robotic-thoracotomy and robotic-sternotomy matched pairs, mortality and morbidity were not significantly different, whereas the robotic approach had lower conversion (1.2% vs 3.1% for robotic-thoracotomy and 1.0% vs 3.7% for robotic-sternotomy), shorter length of stay, and fewer 30-day readmissions. Mortality and morbidity were lower at higher-volume centers, crossing the national mean mortality and morbidity at a cumulative robotic mitral repair case of 40. CONCLUSIONS: Robotic mitral repair is a safe and effective approach and is associated with comparable mortality and morbidity, a lower conversion rate, a shorter length of stay, and fewer 30-day readmissions than thoracotomy or sternotomy approaches.

Insertion of a FLAG-tag sequence at the end of exon 9 of the TBX5 gene in three induced pluripotent stem cell lines (DHMi004-A-4, DHMi004-A-5, DHMi004-A-6) by CRISPR/Cas9 technology.

The identification of TBX5-related regulatory sequences in genes essential for heart development is hampered by the absence of antibodies which allow precipitation of TBX5:DNA complexes. Employing CRISPR/Cas9 technology, we have inserted a FLAG-tag sequence at the end of exon 9 of the TBX5 gene prior to the stop codon by homologous recombination. The translated TBX5-FLAG fusion protein of the three iPSC lines can effectively be precipitated by anti-FLAG antibodies and, thus, allow the detection of specific TBX5-binding sites and their associated genes.

Results of new-generation balloon vs. self-expandable transcatheter heart valves for bicuspid aortic valve stenosis.

Background: Data comparing new-generation self-expandable (SEV, Evolut R/PRO) vs. balloon-expandable (BEV, SAPIEN 3/3Ultra) transcatheter heart valve replacement (TAVR) in bicuspid aortic valve stenosis (BAV) is limited. Our aim was to compare 30-day results of SEV and BEV implantations in patients with BAV. Methods: A total of 2009 patients underwent TAVR between April 2015 and June 2021 at our Centre. From our institutional registry, we identified 106 consecutive patients with BAV who underwent TAVR using SEV and BEV. Results: A 106 patients (n = 68 BEV; n = 38 SEV) were included. Mean age was 74.6 ± 8.8 years (BEV) vs.75.3 ± 8.7 years (SEV) (p = 0.670) and Society of Thoracic Surgeons score was 2.6 ± 1.9 (BEV) vs. 2.6 ± 1.6 (SEV) (p = 0.374), respectively. Device landing zone calcium volume (DLZ-CV) was 1168 ± 811 vs. 945 ± 850 mm3 (p = 0.192). Valve Academic Research Consortium (VARC)-3 device success at 30 days was similar (BEV 80.9% vs. SEV 86.8%; p = 0.433). More post-dilatations were performed in SEVs (23.5% BEV vs. 52.6% SEV; p = 0.002). Overall mean gradient at 30 days follow-up was 11.9 ± 4.6 mmHG (BEV) vs. 9.2 ± 3.0 mmHG (SEV) (p = 0.002). A mild-moderate degree of paravalvular leak (PVL) was detected more often in the SEV group (7.4% vs. 13.2%; p = 0.305). A trend towards higher rate of permanent pacemaker implantation was observed in SEV (11.8% vs. 23.7%; p = 0.109). Conclusions: Treatment of BAV revealed similar performance using BEV and SEV. In this retrospective cohort study, hemodynamics were more favorable with the SEV, although there was a trend toward more PVL and significantly more post-dilations.

Subannular repair in secondary mitral regurgitation with restricted leaflet motion during systole.

OBJECTIVE: Ventricular secondary mitral regurgitation (SMR) (Carpentier type IIIb) results from left ventricular (LV) remodelling, displacement of papillary muscles and tethering of mitral leaflets. The most appropriate treatment approach remains controversial. We aimed to assess the safety and efficacy of standardised relocation of both papillary muscles (subannular repair) at 1-year follow-up (FU). METHODS: REFORM-MR (Reform-Mitral Regurgitation) is a prospective, multicentre registry that enrolled consecutive patients with ventricular SMR (Carpentier type IIIb) undergoing standardised subannular mitral valve (MV) repair in combination with annuloplasty at five sites in Germany. Here, we report survival, freedom from recurrence of MR >2+, freedom from major adverse cardiac and cerebrovascular events (MACCEs), including cardiovascular death, myocardial infarction, stroke, MV reintervention and echocardiographic parameters of residual leaflet tethering at 1-year FU. RESULTS: A total of 94 patients (69.1% male) with a mean age of 65.1±9.7 years met the inclusion criteria. Advanced LV dysfunction (mean left ventricular ejection fraction 36.4±10.5%) and severe LV dilatation (mean left ventricular end-diastolic diameter 61.0±9.3 mm) resulted in severe mitral leaflet tethering (mean tenting height 10.6±3.0 mm) and an elevated mean EURO Score II of 4.8±4.6 prior to surgery. Subannular repair was successfully performed in all patients, without operative mortality or complications. One-year survival was 95.5%. At 12 months, a durable reduction of mitral leaflet tethering resulted in a low rate (4.2%) of recurrent MR >2+. In addition to a significant improvement in New York Heart Association (NYHA) class (22.4% patients in NYHA III/IV vs 64.5% patients at baseline, p<0.001), freedom from MACCE was observed in 91.1% of patients. CONCLUSIONS: Our study demonstrates the safety and feasibility of standardised subannular repair to treat ventricular SMR (Carpentier type IIIb) in a multicentre setting. By addressing mitral leaflet tethering, papillary muscle relocation results in very satisfactory 1-year outcomes and has the potential to durably restore MV geometry; nevertheless, long-term FU is mandatory. TRIAL REGISTRATION NUMBER: NCT03470155.

Immature human engineered heart tissues engraft in a guinea pig chronic injury model.

Engineered heart tissue (EHT) transplantation represents an innovative, regenerative approach for heart failure patients. Late preclinical trials are underway, and a first clinical trial started recently. Preceding studies revealed functional recovery after implantation of in vitro-matured EHT in the subacute stage, whereas transplantation in a chronic injury setting was less efficient. When transplanting matured EHTs, we noticed that cardiomyocytes undergo a dedifferentiation step before eventually forming structured grafts. Therefore, we wanted to evaluate whether immature EHT (EHTIm) patches can be used for transplantation. Chronic myocardial injury was induced in a guinea pig model. EHTIm (15×106 cells) were transplanted within hours after casting. Cryo-injury led to large transmural scars amounting to 26% of the left ventricle. Grafts remuscularized 9% of the scar area on average. Echocardiographic analysis showed some evidence of improvement of left-ventricular function after EHTIm transplantation. In a small translational proof-of-concept study, human scale EHTIm patches (4.5×108 cells) were epicardially implanted on healthy pig hearts (n=2). In summary, we provide evidence that transplantation of EHTIm patches, i.e. without precultivation, is feasible, with similar engraftment results to those obtained using matured EHT.