Utility of routine follow-up defibrillation safety margin testing in young patients with epicardial implantable cardioverter-defibrillators.

BACKGROUND: Routine defibrillation threshold testing (DFT) of transvenous implantable defibrillators (ICDs) has largely been in decline. In patients with non-transvenous ICDs that utilize subcutaneous and pleural ICD leads, serial DFT testing can detect a significant number of failures. Data about the utility of follow-up defibrillation safety margin testing (DSM) testing in pediatric patients and young adults with an epicardial ICD are lacking. METHODS: Patients aged < 25 years old who underwent epicardial ICD placement at Mayo Clinic from 2014 to 2023 with at least one follow-up DSM test were included. The patients were divided into a "routine" (R) and "clinically indicated" (CI) group based on the index of clinical concern. Inadequate DSM was defined as unsuccessful defibrillation at an output of less than 10 J below the maximum output of the device. The purpose of this study was to assess the utility of follow-up DSM testing. RESULTS: An epicardial ICD system was placed in 122 patients. A total of 26 patients met inclusion criteria and underwent a total of 47 DSM follow up tests. Inadequate DSM occurred in 1/33 (3%) in the R group and 2/14 (14%) DSM tests in the CI group. The median follow-up period was 54 and 36 months for the R and CI group, respectively. CONCLUSIONS: Our data suggest that epicardial ICDs are reliable and routine follow-up DSM testing may not be necessary for all patients. DSM testing should be performed in individuals with epicardial ICD systems when there is clinical concern about lead or coil performance.

Hypertrophic Cardiomyopathy: Preadolescence, Mitral Valve Disease, and Midventricular Obstruction.

Septal myectomy is indicated in patients with obstructive hypertrophic cardiomyopathy (HCM) who have persistent symptoms despite medical therapy, intolerance of medication side effects, or severe resting or provocable gradients. Septal myectomy at high volume centers is safe, with low operative mortality (1%) and low rates of complications such as complete heart block or ventricular septal defect (3% and 0.5%, respectively). Additionally, improved survival following myectomy has been observed when compared to patients with obstructive HCM managed medically or those with nonobstructive HCM. As a longstanding, quaternary referral center for septal myectomy, our institution has built significant experience and expertise in the surgical and medical management of HCM, including atypical HCM, defined as preadolescent patients, those with mitral valve disease, and those with isolated midventricular obstruction. The most important factor of septal myectomy in achieving complete resolution of obstruction and avoiding recurrence is the apical extent of the myectomy trough, which must extend to the septum opposite the papillary muscles. If this cannot be fully achieved via a transaortic exposure, especially in preadolescents and patients with midventricular obstruction, then a transapical approach may be needed. Mitral valve repair is rarely necessary as SAM-mediated MR resolves with adequate myectomy alone, but mitral repair is performed in cases of intrinsic valvular disease. In this manuscript we provide a summary of current operative techniques and outcomes data from our institution on the management of these various categories of HCM.

Temporal Changes in Clinical Characteristics and Outcomes of Adults With Congenital Heart Disease.

BACKGROUND: The purpose of this study was to assess differences in the clinical characteristics (defined by congenital heart disease [CHD] anatomic and physiologic classification scheme) of adults with CHD across different eras, and how these differences influence outcomes (heart failure hospitalization and all-cause mortality). METHOD: Patients were divided into depending on year of baseline encounter: cohort #1 (1991-2000, n = 1,984 [27%]), cohort #2 (2001-2010, n = 2,448 [34%]), and cohort #3 (2011-2020, n = 2,847 [39%]). Patients were classified into 3 anatomic groups (simple, moderate, and complex CHD) and 4 physiologic stages (stage A-D). RESULTS: There was a temporal increase in the proportion of patients in physiologic stage C (17% vs 21% vs 24%, P < .001), and stage D (7% vs 8% vs 10%, P = .09), with a corresponding decrease in physiologic stage A (39% vs 35% vs 28%, P < .001). No temporal change in anatomic groups. There was a temporal decrease in the incidence of all-cause mortality (12.7 vs 10.6 vs 9.5 per 1,000 patient-years, P < .001). However, there was a temporal increase in the incidence of heart failure hospitalization (6.8 vs 8.4 vs 11.2 per 1,000 patient-years, P < .001). CHD physiologic stage (but not anatomic groups) was associated with heart failure hospitalization and all-cause mortality. CONCLUSIONS: There is a need for better strategies to identify and treat heart failure, and to modify the risk factors associated with heart failure and all-cause mortality.

Infant Mitral Valve Replacement: Current State of the Art.

Mitral valve replacement (MVR) in the very young is an imposing clinical challenge. Early and late mortality risk is substantial, severe adverse events are common, and redo mitral valve replacement is inevitable. Therapeutic options are limited. In the older infant with an annulus of 17mm or larger, mechanical MVR is associated with low risk of mortality and predictable durability. For the very young with annular hypoplasia, bovine jugular vein conduit MVR appears to offer equivalent or better early outcomes with the possibility of subsequent valve expansion, potentially prolonging the interval to redo MVR. Experience with cylinder MVR and other forms of surgeon-manufactured MVR is quite limited, and there is currently no information on late outcomes or durability.

Intraoperative Versus Postoperative Hydroxocobalamin for Vasoplegic Shock in Cardiothoracic Surgery.

OBJECTIVES: Hydroxocobalamin inhibits nitric oxide pathways contributing to vasoplegic shock in patients undergoing cardiopulmonary bypass (CPB). The objective of this study was to evaluate the effect of intraoperative versus postoperative application of hydroxocobalamin for vasoplegic shock in patients undergoing CPB. DESIGN: This was a historic cohort study. SETTING: The study was conducted at a quaternary academic cardiovascular surgery program. PARTICIPANTS: Adults undergoing cardiac surgery using CPB were participants in the study. INTERVENTIONS: Hydroxocobalamin (5 g) intravenously over 15 minutes. MEASUREMENTS AND MAIN RESULTS: The treatment groups were assigned based on the receipt location of hydroxocobalamin (ie, intensive care unit [ICU] versus operating room [OR]). The primary outcome was vasopressor-free days in the first 14 days after CPB. Of the 112 patients included, 37 patients received hydroxocobalamin in the OR and 75 in the ICU. Patients in the OR group were younger than those in the ICU group (57.5 v 63.9 years, p = 0.007), with statistically similar American Society of Anesthesiologists scores. The mean CPB duration was 3.4 hours in the OR group and 2.9 hours in the ICU group (p = 0.09). In both groups, the norepinephrine-equivalent dose of vasopressors at hydroxocobalamin was 0.27 µg/kg/min. Days alive and free of vasopressors were not different between the OR and ICU groups (estimated difference 0.48 [95% CI -1.76-2.72], p = 0.67). The odds of postoperative renal failure, mesenteric ischemia, ICU, hospital length of stay, and in-hospital mortality were also similar between groups. CONCLUSIONS: A difference in vasopressor-free days after CPB was not found between patients who received hydroxocobalamin intraoperatively versus postoperatively for vasoplegic shock.

Outcomes of cardiac surgery in nonagenarians.

BACKGROUND: While advanced age can be considered by some a contraindication to open-heart surgery, there is a paucity of data regarding outcomes of cardiac surgery in nonagenarians. We, therefore, sought to investigate the outcomes of nonagenarians undergoing cardiac surgery. METHODS: A retrospective review of our institutional Society of Thoracic Surgeons database between 1993 and 2019 was performed. Among a total of 32,421 patients who underwent open-heart surgery, 134 patients (0.4%) were nonagenarians (50.7% females, median age 91.6 [interquartile range: 90.7-92.9]). A comparison was performed between nonagenarians and patients aged 80-89 years. A regression analysis was performed to evaluate factors associated with midterm mortality in nonagenarians. RESULTS: The incidence of cardiac surgery in nonagenarians has been stable over time, from 0.4% in (1993-2000), 0.5% in (2001-2010) to 0.4% in (2011-2019). Valve surgery and CABG+valve were higher in nonagenarians compared to octogenarians (44.8% vs. 25.6%, 39.6% vs. 30.7%, respectively), but CABG was lower (15.7% vs. 33.8%); p < .01. Urgent/emergent surgery status was similar between groups (p = .7). Operative mortality was similar in the two groups (6% vs. 4.6%, p = .5). Hospital complications were comparable between groups. CONCLUSION: Cardiac surgery in nonagenarians can be achieved with acceptable morbidity and mortality. This study can be a benchmark for risk stratification for cardiac surgery in this high-risk population.

Surgical repair of discontinuous right pulmonary artery utilising an autologous main pulmonary artery flap: a case report and literature review.

This is a case of an infant with unilateral discontinuous right pulmonary artery. Cardiac catheterisation with pulmonary wedge injection diagnosed the anomaly and aided in surgical planning. The patient underwent semi-autologous surgical repair utilising an autologous main pulmonary artery flap. One month following discharge, he underwent successful balloon dilation of the residual stenosis and was discharged the same day.

Aortic root replacement for bicuspid aortopathy following heart transplantation.

Although donors with well-functioning bicuspid aortic valves (BAV) are not a contraindication for transplantation, BAV patients are at risk for long-term aortopathy and valve dysfunction. We report a case of a patient status-post heart transplant 13 years ago who presented to our institution with a BAV and severe aortic regurgitation associated with an aortic root aneurysm and underwent aortic root replacement.

Extracellular matrix remodeling in wound healing of critical size defects in the mitral valve leaflet.

The details of valvular leaflet healing following valvuloplasty and leaflet perforation from endocarditis are poorly understood. In this study, the synthesis and turnover of valvular extracellular matrix due to healing of a critical sized wound was investigated. Twenty-nine sheep were randomized to either CTRL (n = 11) or HOLE (n = 18), in which a 2.8-4.8 mm diameter hole was punched in the posterior mitral leaflet. After 12 weeks, posterior leaflets were harvested and histologically stained to localize extracellular matrix components. Immunohistochemistry was also performed to assess matrix components and markers of matrix turnover. A semi-quantitative grading scale was used to quantify differences between HOLE and CTRL. After 12 weeks, the hole diameter was reduced by 71.3 ± 1.4 % (p < 0.001). Areas of remodeling surrounding the hole contained more activated cells, greater expression of proteoglycans, and markers of matrix turnover (prolyl 4-hydroxylase, metalloproteases, and lysyl oxidase, each p ≤ 0.025), along with fibrin accumulation. Two distinct remodeling regions were evident surrounding the hole, one directly bordering the hole rich in versican and hyaluronan and a second adjacent region with abundant collagen and elastic fiber turnover. The remodeling also caused reduced delineation between valve layers (p = 0.002), more diffuse staining of matrix components and markers of matrix turnover (p < 0.001), and disruption of the collagenous fibrosa. In conclusion, acute valve injury elicited distinct, heterogeneous alterations in valvular matrix composition and structure, resulting in partial wound closure. Because these changes could also affect leaflet mechanics and valve function, it will be important to determine their impact on healing wounds.

Repair of ascending aortic aneurysms following cardiac transplantation.

Ascending aortic aneurysms arising from the native aorta following cardiac transplantation are rare. We report two patients who developed aneurysms of the native ascending aorta requiring surgical repair post-transplantation. Both patients underwent ascending and hemi-arch replacement and recovered uneventfully. Heart transplant patients with pre-existing aortic dilation/ectasia may display more rapid aneurysmal growth compared to non-transplant patients. Therefore close observation is warranted in these patients.

Heart Transplantation for Ebstein Anomaly due to Late Surgical Presentation.

Ebstein anomaly is a myopathy of the right ventricle characterized by failure of tricuspid valve delamination with accompanying tricuspid regurgitation. Its rarity, considerable anatomic variability, and frequent absence of symptoms can make the timing of surgery challenging. Contemporary tricuspid repair techniques can be performed with low mortality and bidirectional cavopulmonary anastomosis reduces the risk of operation when right ventricular function is poor. Here, we present a patient who presented late for surgery, failed high-risk conventional surgery and required heart transplantation.

Surgical Considerations for the Mitral Valve in Congenitally Corrected Transposition.

BACKGROUND: Systemic atrioventricular valve (morphologic tricuspid valve [TV]) regurgitation has been implicated in the development of systemic ventricular failure in congenitally corrected transposition of the great arteries (ccTGA), leading to timely referral for valve replacement. However, the surgical management of subpulmonary atrioventricular valve (morphologic mitral valve [MV]) regurgitation and outcomes has not been well studied. METHODS: Of 108 ccTGA patients undergoing atrioventricular valve surgery from 1979 to 2022, 22 patients (20%) underwent MV surgery. Demographics, etiology of valve regurgitation, operative details, and outcomes of these 22 patients were retrospectively reviewed. Follow-up at 1, 5, and 10 years was available for 18 (82%), 13 (59%), and 11 patients (50%), respectively. RESULTS: Median age was 37 years (interquartile range, 29-57 years). Intrinsic MV pathology was present in 18 individuals (82%). Operations included repair in 16 patients (73%), replacement in 6 (27%), and concomitant replacement of TV in 16 (73%). There was 1 perioperative death (5%) in a patient undergoing an emergent operation for severe acute-on-chronic heart failure due to worsening TV regurgitation. During a median follow-up of 12 years (interquartile range, 2-19 years), 7 patients (32%) died. Among the 16 patients who underwent repair, recurrent moderate or greater regurgitation was seen in 15%, 29%, and 43% of repairs in patients with annular, leaflet, and lead-induced regurgitation, respectively. CONCLUSIONS: Concomitant TV and MV disease occur much less frequently than isolated TV disease in ccTGA. Intrinsic MV disease is most commonly observed but appears less amenable to successful repair compared with mitral repair in the systemic position and suggests MV replacement may be preferred in ccTGA patients.

National In-Hospital Outcomes of Mechanical Mitral Valve Replacement in the Pediatric Population.

Background: National data about the outcomes of children undergoing mechanical mitral valve replacement (m-MVR) are scarce. Methods: A retrospective review of hospitalizations from the Kids' Inpatient Database was performed for patients ≤18 years of age in the United States. A total of 500 patients underwent m-MVR in 2009, 2012, 2016, and 2019. Patients with single ventricle physiology were excluded (n = 13). These patients were categorized into three groups according to age: neonates (<1 month, n = 20), infants (1-12 months, n = 76 patients), and children (1-18 years, n = 404). Outcomes were compared between the three groups. Results: The proportion of m-MVR involving children undergoing MV procedures (repair and replacement) has increased from 17.3% in 2009 to 30.8% in 2019 (Ptrend < .01). History of cardiac surgery was present in 256 patients (51.2%). Concomitant procedures were performed in 119 patients (23.8%). Intra- or postoperative extracorporeal membrane oxygenation was required in 19 patients (3.8%). The overall in-hospital mortality was 4.8% and was significantly higher in neonates and infants compared with older children (10% vs 11.8% vs 3.2%, P = .003). The length of hospital stay was longer in the neonatal group (median, 57 days, interquartile range, [24.8-90] vs 29.5 days [15.5-61] vs 10 days [7-18], P < .01). Nonhome discharges were more common in neonates and infants (40% vs 36.8% vs 13.1%, P < .01). Conclusion: Mechanical mitral valve replacement is increasingly performed over time with acceptable in-hospital morbidity and mortality, especially in older children and adolescents. Neonates and infants are associated with worse hospital survival, prolonged hospitalization, and significant rates of nonhome discharges.