Intervention for critical aortic stenosis in Hutchinson-Gilford progeria syndrome.

Hutchinson-Gilford Progeria Syndrome (HGPS) is an ultra-rare genetic premature aging disease that is historically fatal in teenage years, secondary to severe accelerated atherosclerosis. The only approved treatment is the farnesyltransferase inhibitor lonafarnib, which improves vascular structure and function, extending average untreated lifespan of 14.5 years by 4.3 years (30%). With this longer lifespan, calcific aortic stenosis (AS) was identified as an emerging critical risk factor for cardiac death in older patients. Intervention to relieve critical AS has the potential for immediate improvement in healthspan and lifespan. However, HGPS patient-device size mismatch, pervasive peripheral arterial disease, skin and bone abnormalities, and lifelong failure to thrive present unique challenges to intervention. An international group of experts in HGPS, pediatric and adult cardiology, cardiac surgery, and pediatric critical care convened to identify strategies for successful treatment. Candidate procedures were evaluated by in-depth examination of 4 cases that typify HGPS clinical pathology. Modified transcatheter aortic valve replacement (TAVR) and left ventricular Apico-Aortic Conduit (AAC) placement were deemed high risk but viable options. Two cases received TAVR and 2 received AAC post-summit. Three were successful and 1 patient died perioperatively due to cardiovascular disease severity, highlighting the importance of intervention timing and comparative risk stratification. These breakthrough interventions for treating critical aortic stenosis in HGPS patients could rewrite the current clinical perspective on disease course by greatly improving late-stage quality of life and increasing lifespan. Expanding worldwide medical and surgical competency for this ultra-rare disease through expert information-sharing could have high impact on treatment success.

Early and long-term outcomes following cardiac surgery for patients with heterotaxy syndrome.

Objective: Heterotaxy syndrome is a complex multisystem abnormality historically associated with high morbidity and mortality. We sought to evaluate the early and long-term outcomes after cardiac surgery in heterotaxy syndrome. Methods: This is a single-center retrospective review of patients with heterotaxy syndrome undergoing single-ventricle palliation or primary or staged biventricular repair from 1998 to 2018. Patients were stratified by single ventricle versus biventricular physiology, and the severity of atrioventricular valve regurgitation. Demographics, anatomic characteristics, and early and late outcomes, including the length of stay, mortality, and surgical or catheter reinterventions, were analyzed. Results: Among 250 patients, 150 (60%) underwent biventricular repair. In-hospital mortality was 7.6% (n = 19). Median follow-up was 5.2 (range, 0-16) years. Among survivors to discharge, mortality was 19% (n = 44) and reintervention was 52% (n = 120). Patients with moderate/severe atrioventricular valve regurgitation were older (32 vs 16 months, P = .02), were more likely to experience adverse events during their index surgical admission (72% vs 46%, P < .001), and had longer in-hospital length of stay (20 vs 12 days, P = .009). Among patients with moderate to severe atrioventricular valve regurgitation, single-ventricle palliation is associated with a greater risk of unplanned reintervention compared with patients undergoing biventricular repair (hazard ratio, 2.13; CI, 1.10-4.12; P = .025). Conclusions: There was no significant difference in early or late outcomes in single-ventricle versus biventricular repair strategies in heterotaxy. In the subgroup of patients with moderate/severe atrioventricular valve regurgitation, patients who underwent single-ventricle palliation were 2.5 times more likely to need a late reintervention compared with those undergoing biventricular repair.

Impact of Age-Related Change in Caval Flow Ratio on Hepatic Flow Distribution in the Fontan Circulation.

BACKGROUND: The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac conduit or a lateral tunnel connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics. The effect of age-related changes in caval inflows on HFD was evaluated using cardiac magnetic resonance data and patient-specific computational fluid dynamics modeling. METHODS: SVC and IVC flow from 414 patients with Fontan were collected to establish a relationship between SVC:IVC flow ratio and age. Computational fluid dynamics modeling was performed in 60 (30 extracardiac and 30 lateral tunnel) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively. RESULTS: SVC:IVC flow ratio inverted at ≈8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC, 2, 1, and 0.5 corresponded to ages, 3, 8, and 15+, respectively) was not significant for extracardiac but statistically significant for lateral tunnel cohorts. For all 3 caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2 to 0.5 (age, 3-15+) years, the correlation's strength decreased from 0.87 to 0.64, due to potential flow perturbation as IVC flow momentum increased. CONCLUSIONS: Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of SVC:IVC variations over time on Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes.

Erector spinae plane blocks for opioid-sparing multimodal pain management after pediatric cardiac surgery.

OBJECTIVE: Peripheral regional anesthesia is proposed to enhance recovery. We sought to evaluate the efficacy of bilateral continuous erector spinae plane blocks (B-ESpB) for postoperative analgesia and the impact on recovery in children undergoing cardiac surgery. METHODS: Patients aged 2 through 17 years undergoing cardiac surgery in the enhanced recovery after cardiac surgery program were prospectively enrolled to receive B-ESpB at the end of the procedure, with continuous infusions via catheters postoperatively. Participants wore an activity monitor until discharge. B-ESpB patients were retrospectively matched with control patients in the enhanced recovery after cardiac surgery program. Outcomes of the matched clusters were compared using exact conditional logistic regression and generalized linear modeling. RESULTS: Forty patients receiving B-ESpB were matched to 78 controls. There were no major complications from the B-ESpB or infusions, and operating room time was longer by a median of 31 minutes. While blocks were infusing, patients with B-ESpB received fewer opioids in oral morphine equivalents than controls at 24 hours (0.60 ± 0.06 vs 0.78 ± 0.04 mg/kg; P = .02) and 48 hours (1.13 ± 0.08 vs 1.35 ± 0.06 mg/kg; P = .04), respectively. Both groups had low median pain scores per 12-hour period. There was no difference in early mobilization, length of stay, or complications. CONCLUSIONS: B-ESpBs are safe in children undergoing cardiac surgery. When performed as part of a multimodal pain strategy in an enhanced recovery after cardiac surgery program, pediatric patients with B-ESpB experience good pain control and require fewer opioids in the first 48 hours.

Association of tetralogy of Fallot and complete atrioventricular canal: a single-centre 40-year experience.

OBJECTIVES: Outcome data in tetralogy of Fallot (ToF) and complete atrioventricular canal (CAVC) are limited. We report our experience for over 40 years in this patient population. METHODS: Single-centre, retrospective analysis of patients who underwent surgical repair with the diagnosis of ToF-CAVC from 1979 to 2022, divided into 2 different periods and compared. RESULTS: A total of 116 patients were included: 1979-2007 (n = 61) and 2008-2021 (n = 55). Balanced CAVC (80%) and Rastelli type C CAVC (81%) were most common. Patients in the later era were younger (4 vs 14 months, P < 0.001), fewer had trisomy 21 (60% vs 80%, P = 0.019) and fewer had prior palliative prior procedures (31% vs 43%, P < 0.001). In the earlier era, single-patch technique was more common (62% vs 16%, P < 0.001), and in recent era, double-patch technique was more common (84% vs 33%, P < 0.001). In the earlier era, right ventricular outflow tract was most commonly reconstructed with transannular patch (51%), while in more recent era, valve-sparing repairs were more common (69%) (P < 0.001). In-hospital mortality was 4.3%. The median follow-up was 217 and 74 months for the first and second eras. Survival for earlier and later eras at 2-, 5- and 10-year follow-up was (85.1%, 81.5%, 79.6% vs 94.2%, 94.2%, 94.2% respectively, log-rank test P = 0.03). CONCLUSIONS: The surgical approach to ToF-CAVC has evolved over time. More recently, patients tended to receive primary repair at younger ages and had fewer palliative procedures. Improved surgical techniques allowing for earlier and complete repair have shown a decrease in mortality, more valve-sparing procedures without an increase in total reoperations. Presented at the 37th EACTS Annual Meeting, Vienna, Austria.

Comparing apples to apples: Exploring public reporting of congenital cardiac surgery outcomes based on common congenital heart operations.

OBJECTIVE: We sought to simplify reporting of outcomes in congenital heart surgery that compares well-defined patient groups and accommodates multiple stakeholder needs while being easily understandable. METHODS: We selected 19 commonly performed congenital heart surgeries ranging in complexity from repair of atrial septal defects to the Norwood procedure. Strict inclusion/exclusion criteria ensured the creation of 19 well-defined diagnosis/procedure cohorts. Preoperative, procedural, and postoperative data were collected for consecutive eligible patients from 9 centers between January 1, 2016, and December 31, 2021. Unadjusted operative mortality rates and hospital length of stay for each of the 19 diagnosis/procedure cohorts were summarized in aggregate and stratified by each center. RESULTS: Of 8572 eligible cases included, numbers in the 19 diagnosis/procedure cohorts ranged from 73 for tetralogy of Fallot repair after previous palliation to 1224 for ventricular septal defect (VSD) repair for isolated VSD. In aggregate, the unadjusted mortality ranged from 0% for atrial septal defect repair to 28.4% for hybrid stage I. There was significant heterogeneity in case mix and mortality for different diagnosis/procedure cohorts across centers (eg, arterial switch operation/VSD, n = 7-42, mortality 0%-7.4%; Norwood procedure, n = 16-122, mortality 5.3%-25%). CONCLUSIONS: Reporting of institutional case volumes and outcomes within well-defined diagnosis/procedure cohorts can enable centers to benchmark outcomes, understand trends in mortality, and direct quality improvement. When made public, this type of report could provide parents with information on institutional volumes and outcomes and allow them to better understand the experience of each program with operations for specific congenital heart defects.

Prognostic utility of a novel risk prediction model of 1-year mortality in patients surviving to discharge after surgery for congenital or acquired heart disease.

OBJECTIVE: We sought to develop a novel risk prediction model of 1-year mortality after congenital heart surgery that accounts for clinical, anatomic, echocardiographic, and socioeconomic factors. METHODS: This was a single-center, retrospective review of consecutive index operations for congenital or acquired heart disease, from January 2011 to January 2021, among patients with known survival status at 1 year after discharge from the index hospitalization. The primary outcome was postdischarge mortality at 1 year. Variables of interest included age, prematurity, noncardiac anomalies or syndromes, the Childhood Opportunity Index, primary procedure, major adverse postoperative complications, and the Residual Lesion Score. Logistic regression was used to develop a weighted risk score for the primary outcome. Internal validation using a bootstrap-resampling approach was performed. RESULTS: Of 10,412 consecutive operations for congenital or acquired heart disease, 8808 (84.6%) cases met entry criteria, including survival to discharge. There were 190 (2.2%) deaths at 1 year postdischarge. A weighted risk score was formulated on the basis of the variables in the final risk prediction model, which included all aforementioned risk factors of interest. This model had a C-statistic of 0.82 (95% confidence interval, 0.80-0.85). The median risk score was 6 (interquartile range, 4-8) points. Patients were categorized as low (score 0-5), medium (score 6-10), high (score 11-15), or very high (score 16-20) risk. The expected probability of mortality was 0.4% ± 0.2%, 2.0% ± 1.1%, 10.1% ± 5.0%, and 36.6% ± 9.6% for low-risk, medium-risk, high-risk, and very high-risk patients, respectively. CONCLUSIONS: A risk prediction model of 1-year mortality may guide prognostication and follow-up of patients after discharge after surgery for congenital or acquired heart disease.

Growth of the Neo-Aortic Root and Prognosis of Transposition of the Great Arteries.

BACKGROUND: Neo-aortic root dilatation can lead to significant late morbidity after the arterial switch operation (ASO) for dextro-transposition of the great arteries (d-TGA). OBJECTIVES: We sought to examine the growth of the neo-aortic root in d-TGA. METHODS: A single-center, retrospective cohort study of patients who underwent the ASO between July 1, 1981 and September 30, 2022 was performed. Morphology was categorized as dextro-transposition of the great arteries with intact ventricular septum (d-TGA-IVS), dextro-transposition of the great arteries with ventricular septal defect (d-TGA-VSD), and double-outlet right ventricle-transposition of the great arteries type (DORV-TGA). Echocardiographically determined diameters and derived z scores were measured at the annulus, sinus of Valsalva, and sinotubular junction immediately before the ASO and throughout follow-up. Trends in root dimensions over time were assessed using linear mixed-effects models. The association between intrinsic morphology and the composite of moderate-severe aortic regurgitation (AR) and neo-aortic valve or root intervention was evaluated with univariable and multivariable Cox proportional hazards models. RESULTS: Of 1,359 patients who underwent the ASO, 593 (44%), 666 (49%), and 100 (7%) patients had d-TGA-IVS, d-TGA-VSD, and DORV-TGA, respectively. Each patient underwent a median of 5 echocardiograms (Q1-Q3: 3-10 echocardiograms) over a median follow-up of 8.6 years (range: 0.1-39.3 years). At 30 years, patients with DORV-TGA demonstrated greater annular (P < 0.001), sinus of Valsalva (P = 0.039), and sinotubular junction (P = 0.041) dilatation relative to patients with d-TGA-IVS. On multivariable analysis, intrinsic anatomy, older age at ASO, at least mild AR at baseline, and high-risk root dilatation were associated with moderate-severe AR and neo-aortic valve or root intervention at late follow-up (all P < 0.05). CONCLUSIONS: Longitudinal surveillance of the neo-aortic root is warranted long after the ASO.

Right ventricular papillary muscle approximation to the septum as an adjunct technique during tricuspid valve repair in congenital heart surgery.

OBJECTIVE: Tricuspid regurgitation is often caused by leaflet splaying from displaced papillary muscles or ventricular dilatation. Traditional annuloplasty may not address this mechanism. The present study describes a single institution's experience using right ventricular papillary muscle approximation for tricuspid valve repair. METHODS: Right ventricular papillary muscle approximation consists of suturing the anterior papillary muscle to a point of the septum (septum or septal papillary muscle) that optimizes leaflet coaptation. We describe our technique and analyze clinical data of patients undergoing tricuspid valve repair with right ventricular papillary muscle approximation during congenital heart surgery between 2012 and 2021. RESULTS: Right ventricular papillary muscle approximation was performed as an adjunct procedure in 207 of 825 tricuspid valve repairs (25.1%). Discharge tricuspid regurgitation grade was mild tricuspid regurgitation or less in 153 patients (73.9%), and 140 patients (67.6%) had mild tricuspid regurgitation or less at a median latest follow-up of 3.2 years (interquartile range, 0.7-6.8). Thirty patients (14.5%) underwent 11 early tricuspid valve reinterventions (3 due to right ventricular papillary muscle approximation dehiscence) and 21 late tricuspid valve reinterventions. Estimated 5-year freedom from tricuspid valve reintervention was 84% (95% CI, 77.0-89.2). Systemic right ventricle physiology (odds ratio, 2.88, P = .048) and multiple mechanisms of tricuspid regurgitation (odds ratio, 7.35, P = .038) were significant predictors of tricuspid valve reintervention on multivariable analysis. CONCLUSIONS: Tricuspid valve repair with right ventricular papillary muscle approximation demonstrates acceptable short-term durability, but similar to other tricuspid valve repair strategies is less durable in patients with systemic right ventricle pressure and multiple mechanisms of tricuspid regurgitation. Right ventricular papillary muscle approximation is a safe and effective adjunct technique that should be considered in patients with tricuspid regurgitation caused by leaflet splaying from displaced papillary muscles or right ventricle dilatation.

Postoperative Troponin Levels in Children Undergoing Open Heart Surgery With and Without Coronary Intervention.

We aimed to characterize the ranges, temporal trends, influencing factors, and prognostic significance of postoperative troponin levels after congenital heart surgery. This single-center retrospective study included patients from 2006 to 2021 who had ≥ 1 postoperative troponin-T measurement collected within 96 h of congenital heart surgery (CHS). Patients were grouped as Anomalous Aortic Origin of the Coronary Artery-"AAOCA repair," or congenital heart surgery with "Other Coronary Interventions" other than AAOCA repair, or "No Coronary Intervention." In each group, information on concomitant surgery requiring one or more of the following-atriotomy, ventriculotomy, right ventricular muscle bundle resection, and/or septal myectomy-was collected. Clinical correlates of troponin values were analyzed in three postoperative windows: < 8, 8-24, and 24-48 h. The highest median [range] troponin levels (ng/mL) for the samples were 0.34 [0.06, 1.32] at < 8 h for "AAOCA repair," 1.35 [0.14, 12.0] at < 8 h for those undergoing CHS with "Other Coronary Interventions," and 0.87 [0.06, 25.1] at 8-24 h for those undergoing CHS with "No Coronary Interventions." Atriotomy was associated with higher median troponin levels in the AAOCA group at < 8 h (0.40 [0.31, 0.77] vs. 0.29 [0.17, 0.54], P = 0.043) and in the Other Coronary Intervention group at 8-24 h (1.67 [1.04, 2.63] vs. 0.40 [0.19, 1.32], P = 0.002). Patients experiencing major postoperative complications (vs. those who did not) had higher troponin levels in the AAOCA group as early as 8-24 h (0.36 [0.24, 0.57] vs. 0.21 [0.14, 0.33], P = 0.03). Similar findings were noted in the Coronary Intervention (2.20 [1.34, 3.90] vs. 1.11 [0.51, 2.90], P = 0.028) and No Coronary Intervention (2.2 [1.49, 15.1] vs. 0.74 [0.40, 2.34], P = 0.027) groups but earlier at < 8 h. In the AAOCA group, 2/18 (11%) troponin outliers experienced cardiac arrest in comparison to 0/80 (0%) non-outliers (P = 0.032). In the Other Coronary Intervention group, troponin outliers had longer median times to ICU discharge (10 vs. 4 days) and hospital discharge (21 vs. 10 days) (both P < 0.001). Postoperative troponin levels depend on a multitude of factors and may have prognostic value in patients undergoing congenital heart surgery with coronary interventions.

Mitochondrial transplantation preserves myocardial function and viability in pediatric and neonatal pig hearts donated after circulatory death.

OBJECTIVE: Mitochondrial transplantation has been shown to preserve myocardial function and viability in adult porcine hearts donated after circulatory death (DCD) . Herein, we investigate the efficacy of mitochondrial transplantation for the preservation of myocardial function and viability in neonatal and pediatric porcine DCD heart donation. METHODS: Circulatory death was induced in neonatal and pediatric Yorkshire pigs by cessation of mechanical ventilation. Hearts underwent 20 or 36 minutes of warm ischemia time (WIT), 10 minutes of cold cardioplegic arrest, and then were harvested for ex situ heart perfusion (ESHP). Following 15 minutes of ESHP, hearts received either vehicle (VEH) or vehicle containing isolated autologous mitochondria (MITO). A sham nonischemic group (SHAM) did not undergo WIT, mimicking donation after brain death heart procurement. Hearts underwent 2 hours each of unloaded and loaded ESHP perfusion. RESULTS: Following 4 hours of ESHP perfusion, left ventricle developed pressure, dP/dt max, and fractional shortening were significantly decreased (P < .001) in DCD hearts receiving VEH compared with SHAM hearts. In contrast, DCD hearts receiving MITO exhibited significantly preserved left ventricle developed pressure, dP/dt max, and fractional shortening (P < .001 each vs VEH, not significant vs SHAM). Infarct size was significantly decreased in DCD hearts receiving MITO as compared with VEH (P < .001). Pediatric DCD hearts subjected to extended WIT demonstrated significantly preserved fractional shortening and significantly decreased infarct size with MITO (P < .01 each vs VEH). CONCLUSIONS: Mitochondrial transplantation in neonatal and pediatric pig DCD heart donation significantly enhances the preservation of myocardial function and viability and mitigates against damage secondary to extended WIT.

Transcatheter Palliation With Pulmonary Artery Flow Restrictors in Neonates With Congenital Heart Disease: Feasibility, Outcomes, and Comparison With a Historical Hybrid Stage 1 Cohort.

BACKGROUND: Neonates with complex congenital heart disease and pulmonary overcirculation have been historically treated surgically. However, subcohorts may benefit from less invasive procedures. Data on transcatheter palliation are limited. METHODS: We present our experience with pulmonary flow restrictors (PFRs) for palliation of neonates with congenital heart disease, including procedural feasibility, technical details, and outcomes. We then compared our subcohort of high-risk single ventricle neonates palliated with PFRs with a similar historical cohort who underwent a hybrid Stage 1. Cox regression was used to evaluate the association between palliation strategy and 6-month mortality. RESULTS: From 2021 to 2023, 17 patients (median age, 4 days; interquartile range [IQR], 2-8; median weight, 2.5 kilograms [IQR, 2.1-3.3]) underwent a PFR procedure; 15 (88%) had single ventricle physiology; 15 (88%) were high-risk surgical candidates. All procedures were technically successful. At a median follow-up of 6.2 months (IQR, 4.0-10.8), 13 patients (76%) were successfully bridged to surgery (median time since PFR procedure, 2.6 months [IQR, 1.1-4.4]; median weight, 4.9 kilograms [IQR, 3.4-5.8]). Pulmonary arteries grew adequately for age, and devices were easily removed without complications. The all-cause mortality rate before target surgery was 24% (n=4). Compared with the historical hybrid stage 1 cohort (n=23), after adjustment for main confounding (age, weight, intact/severely restrictive atrial septum or left ventricle to coronary fistulae), the PFR procedure was associated with a significantly lower all-cause 6-month mortality risk (adjusted hazard ratio, 0.26 [95% CI, 0.08-0.82]). CONCLUSIONS: Transcatheter palliation with PFR is feasible, safe, and represents an effective strategy for bridging high-risk neonates with congenital heart disease to surgical palliation, complete repair, or transplant while allowing for clinical stabilization and somatic growth.

Prognostic utility of a risk prediction model for predischarge major residual lesions or unplanned reinterventions following congenital mitral valve repair.

OBJECTIVE: We sought to develop a risk prediction model for predischarge major mitral valve (MV) residual lesions or unplanned MV reinterventions following congenital MV repair. METHODS: Patients who underwent congenital MV repair (excluding primary repair, but including secondary repair, of canal-type defects) at a single institution from January 2000 to December 2020 and survived to discharge were retrospectively reviewed. The primary outcome was major MV residua (mean gradient >6 mm Hg or moderate or greater regurgitation on the discharge echocardiogram) or predischarge unplanned MV reintervention. Risk factors of interest included age, single-ventricle physiology, preoperative and intraoperative postrepair MV stenosis and regurgitation severity, MV annular diameter z score, systemic ventricle ejection fraction, unfavorable anatomy, concomitant left-heart procedure, and various technique-related categories. Logistic regression was used to develop a weighted risk score for the primary outcome. Internal validation using bootstrap-resampling was performed. RESULTS: Of 866 patients who underwent congenital MV repair at a median age of 2.7 years (interquartile range, 0.7-9.1 years), 202 (23.3%) patients developed the primary outcome. The final risk prediction model had a C-statistic of 0.82 (95% confidence interval, 0.78-0.85). A weighted risk score was formulated per the variables in this model. The median risk score was 8 (interquartile range, 6-11) points. Patients were categorized as low (score 0-5), medium (score 6-10), high (score 11-15), or very high (score ≥16) risk. The probability of the primary outcome was 5.0 ± 1.7%, 15.2 ± 6.7%, 45.9 ± 12.6%, and 76.7 ± 8.8% for low-, medium-, high-, and very-high-risk patients, respectively. CONCLUSIONS: Our risk prediction model may guide prognostication of patients following congenital MV repair.

Model of Ischemia and Reperfusion Injury in Rabbits.

The protocol here provides a simple, highly replicable methodology to induce in situ acute regional myocardial ischemia in the rabbit for non-survival and survival experiments. New Zealand White adult rabbit is sedated with atropine, acepromazine, butorphanol, and isoflurane. The animal is intubated and placed on mechanical ventilation. An intravenous catheter is inserted into the marginal ear vein for the infusion of medications. The animal is pre-medicated with heparin, lidocaine, and lactated Ringer's solution. A carotid cut-down is performed to obtain arterial line access for blood pressure monitoring. Select physiologic and mechanical parameters are monitored and recorded by continuous real-time analysis. With the animal sedated and fully anesthetized, either a fourth intercostal space small left thoracotomy (survival) or midline sternotomy (non-survival) is performed. The pericardium is opened, and the left anterior descending (LAD) artery is located. A polypropylene suture is passed around the second or third diagonal branch of the LAD artery, and the polypropylene filament is threaded through a small vinyl tube, forming a snare. The animal is subjected to 30 min of regional ischemia, achieved by occluding the LAD by tightening the snare. Myocardial ischemia is confirmed visually by regional cyanosis of the epicardium. Following regional ischemia, the ligature is loosened, and the heart is allowed to re-perfuse. For both survival and non-survival experiments, the myocardial function can be assessed via an echocardiography (ECHO) measurement of the fractional shortening. For non-survival studies, data from sonomicrometry collected using three digital piezoelectric ultrasonic probes implanted within the ischemic area and the left ventricle developed pressure (LVDP) using an apically inserted left ventricle (LV) catheter can be continuously acquired for evaluating the regional and global myocardial function, respectively. For survival studies, the incision is closed, a left needle thoracentesis is performed for pleural air evacuation, and postoperative pain control is achieved.

Mechanical failure analysis of patch materials used in aortic arch reconstruction: implications for clinical practice.

OBJECTIVES: Thick-patch pulmonary homograft, autologous pericardium and CardioCel Neo are common patch materials for aortic arch reconstruction. Insufficient data exist on sutured patch strength and limits of use. We evaluated failure strength of these materials to develop a failure prediction model for clinical guidance. METHODS: Patch failure strength was evaluated via sutured uniaxial and burst pressure testing. In sutured uniaxial testing, patches were sutured to aortic or Dacron tabs and pulled to failure. In burst pressure testing, patches were sewn into porcine aortas or Dacron grafts and pressurized to failure. Failure membrane tension was calculated. A prediction model of membrane tension versus vessel diameter was generated to guide clinical patch selection. RESULTS: Combining sutured uniaxial and burst pressure test data, pulmonary homograft failure strength {0.61 [interquartile range (IQR): 0.44, 0.78] N/mm, n = 21} was less than half that of autologous pericardium [2.22 (IQR: 1.65, 2.78) N/mm, n = 15] and CardioCel Neo [1.31 (IQR: 1.20, 1.42) N/mm, n = 20]. Pulmonary homograft burst pressure [245 (IQR: 202, 343) mmHg, n = 7] was significantly lower than autologous pericardium [863 (IQR: 802, 919) mmHg, n = 6] and CardioCel Neo [766 (IQR: 721, 833) mmHg, n = 6]. Our model predicts failure limits for each patch material and outlines safety margins for combinations of aortic diameter and pressure. CONCLUSIONS: Sutured failure strength of thick-patch pulmonary homograft was significantly lower than autologous pericardium and CardioCel Neo. Patient selection (predicted postoperative arch diameter and haemodynamics) and blood pressure management must be considered when choosing patch material for arch reconstruction. In older children and adolescents, autologous or bovine pericardium may be more suitable materials for aortic patch augmentation to minimize the risk of postoperative patch failure.

A Neonatal Heterotopic Rat Heart Transplantation Model for the Study of Endothelial-to-Mesenchymal Transition.

Endocardial fibroelastosis (EFE), defined by subendocardial tissue accumulation, has major impacts on the development of the left ventricle (LV) and precludes patients with congenital critical aortic stenosis and hypoplastic left heart syndrome (HLHS) from curative anatomical biventricular surgical repair. Surgical resection is currently the only available therapeutic option, but EFE often recurs, sometimes with an even more infiltrative growth pattern into the adjacent myocardium. To better understand the underlying mechanisms of EFE and to explore therapeutic strategies, an animal model suitable for preclinical testing was developed. The animal model takes into consideration that EFE is a disease of the immature heart and is associated with flow disturbances, as supported by clinical observations. Thus, the heterotopic heart transplantation of neonatal rat donor hearts is the basis for this model. A neonatal rat heart is transplanted into an adolescent rat's abdomen and connected to the recipient's infrarenal aorta and inferior vena cava. While perfusion of the coronary arteries preserves the viability of the donor heart, flow stagnation within the LV induces EFE growth in the very immature heart. The underlying mechanism of EFE formation is the transition of endocardial endothelial cells to mesenchymal cells (EndMT), which is a well-described mechanism of early embryonic development of the valves and septa but also the leading cause of fibrosis in heart failure. EFE formation can be macroscopically observed within days after transplantation. Transabdominal echocardiography is used to monitor the graft viability, contractility, and the patency of the anastomoses. Following euthanasia, the EFE tissue is harvested, and it shows the same histopathological characteristics as human EFE tissue from HLHS patients. This in vivo model allows for studying the mechanisms of EFE development in the heart and testing treatment options to prevent this pathological tissue formation and provides the opportunity for a more generalized examination of EndMT-induced fibrosis.

Photopolymerizable Hydrogel for Enhanced Intramyocardial Vascular Progenitor Cell Delivery and Post-Myocardial Infarction Healing.

Cell transplantation success for myocardial infarction (MI) treatment is often hindered by low engraftment due to washout effects during myocardial contraction. A clinically viable biomaterial that enhances cell retention can optimize intramyocardial cell delivery. In this study, a therapeutic cell delivery method is developed for MI treatment utilizing a photocrosslinkable gelatin methacryloyl (GelMA) hydrogel. Human vascular progenitor cells, capable of forming functional vasculatures upon transplantation, are combined with an in situ photopolymerization approach and injected into the infarcted zones of mouse hearts. This strategy substantially improves acute cell retention and promotes long-term post-MI cardiac healing, including stabilized cardiac functions, preserved viable myocardium, and reduced cardiac fibrosis. Additionally, engrafted vascular cells polarize recruited bone marrow-derived neutrophils toward a non-inflammatory phenotype via transforming growth factor beta (TGFß) signaling, fostering a pro-regenerative microenvironment. Neutrophil depletion negates the therapeutic benefits generated by cell delivery in ischemic hearts, highlighting the essential role of non-inflammatory, pro-regenerative neutrophils in cardiac remodeling. In conclusion, this GelMA hydrogel-based intramyocardial vascular cell delivery approach holds promise for enhancing the treatment of acute myocardial infarction.