Invited Commentary: Notwithstanding the Significance of Anatomy in Anomalous Aortic Origin of a Coronary Artery, Physiology Is Important, Too.

The management strategies for anomalous aortic origin of a coronary artery (AAOCA) are based on anatomy, symptoms, and stress tests for evidence of ischemia. These strategies remain associated with low levels of evidence. Stress tests for ischemia or ventricular dysfunction, the only widely used physiological tests, are not adequately reliable. Additional physiological metrics are needed to build reliable strategies. Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are physiological measurements that are used in assessing acquired coronary artery disease (CAD). In this commentary, we describe FFR and iFR and review studies supporting their utility in assessing CAD. We describe a few small studies of their use in assessing AAOCA. Finally, we comment on the unique features of AAOCA that mandate further investigation on how to conduct and interpret FFR/iFR measurements. Even at a point where we understand how to do this, determining the effectiveness of these measurements in improving outcomes and guiding management will require lengthy and challenging trials. A collective effort of institutions that manage AAOCA will be essential.

The Academic Impact of Congenital Heart Surgeons' Society (CHSS) Studies.

PURPOSE: We reviewed all 64 articles ever published by The Congenital Heart Surgeons' Society (CHSS) Data Center to estimate the academic impact of these peer-reviewed articles. MATERIALS AND METHODS: The Congenital Heart Surgeons' Society has performed research based on 12 Diagnostic Inception Cohorts. The first cohort (Transposition) began enrolling patients on January 1, 1985. We queried PubMed to determine the number of publications that referenced each of the 64 journal articles generated by the datasets of the 12 Diagnostic Inception Cohorts that comprise the CHSS Database. Descriptive summaries of the data were tabulated using mean with standard deviation and median with range. RESULTS: Sixty-four peer-reviewed papers have been published based on the CHSS Database. Fifty-nine peer-reviewed articles have been published based on the 12 Diagnostic Inception Cohorts, and five additional articles have been published based on Data Science. Excluding the recently established Diagnostic Inception Cohort for patients with Ebstein malformation of tricuspid valve, the number of papers published per cohort ranged from 1 for coarctation to 11 for transposition of the great arteries. The 11 articles generated from the CHSS Transposition Cohort were referenced by a total of 111 articles (median number of references per journal article = 9 [range = 0-22, mean = 10.1]). Overall, individual articles were cited by an average of 11 (mean), and a maximum of 41 PubMed-listed publications. Overall, these 64 peer-reviewed articles based on the CHSS Database were cited 692 times in PubMed-listed publications. The first CHSS peer-reviewed article was published in 1987, and during the 35 years from 1987 to 2022, inclusive, the annual number of CHSS publications has ranged from 0 to 7, with a mean of 1.8 publications per year (median = 1, mode = 1). CONCLUSION: Congenital Heart Surgeons' Society studies are widely referenced in the pediatric cardiac surgical literature, with over 10 citations per published article. These cohorts provide unique information unavailable in other sources of data. A tool to access this analysis is available at: [https://data-center.chss.org/multimedia/files/2022/CAI.pdf].

Research Enterprise of the Congenital Heart Surgeons' Society 2018 to 2023: History, Accomplishments, Transformation, and Challenges.

The history of the research arm of the Congenital Heart Surgeons' Society (CHSS) through 2017 was contained within two prior publications that covered CHSS history in general. The present article is the first to focus explicitly on the research enterprise, with emphasis on the period 2018 to 2023. During this time, the challenges of continuing to build multiple cohorts with lifelong follow-up and to transform the enterprise to a premiere research organization became manifest. Although continuing its commitment to produce impactful research results and to educate the Kirklin/Ashburn Fellow, the research team devoted considerable effort to defining the problems of cohort relevance, workflow, data management, long-term patient follow-up, CHSS member engagement, and the regulatory burden. The team wrote a proposal outlining ways to solve the challenges. A major change from a single-institution "Data Center" to a two-institution Center for Research & Quality (CRQ) was made, assuring increased faculty members and resources. The proposed changes to structure and process began execution in mid-2022. A second Kirklin/Ashburn Fellowship position was created. Between 2018 and 2022, the CRQ produced 17 publications and launched five new research initiatives. This article chronicles the exciting five-year period in which the CHSS research enterprise began a transformation with the intent to become the premiere research organization in the world in the specialty of congenital cardiac surgery.

A dynamic Norwood mortality estimation: Characterizing individual, updated, predicted mortality trajectories after the Norwood operation.

Objective: Post-Norwood mortality remains high and unpredictable. Current models for mortality do not incorporate interstage events. We sought to determine the association of time-related interstage events, along with (pre)operative characteristics, with death post-Norwood and subsequently predict individual mortality. Methods: From the Congenital Heart Surgeons' Society Critical Left Heart Obstruction cohort, 360 neonates underwent Norwood operations from 2005 to 2016. Risk of death post-Norwood was modeled using a novel application of parametric hazard analysis, in which baseline and operative characteristics and time-related adverse events, procedures, and repeated weight and arterial oxygen saturation measurements were considered. Individual predicted mortality trajectories that dynamically update (increase or decrease) over time were derived and plotted. Results: After the Norwood, 282 patients (78%) progressed to stage 2 palliation, 60 patients (17%) died, 5 patients (1%) underwent heart transplantation, and 13 patients (4%) were alive without transitioning to another end point. In total, 3052 postoperative events occurred and 963 measures of weight and oxygen saturation were obtained. Risk factors for death included resuscitated cardiac arrest, moderate or greater atrioventricular valve regurgitation, intracranial hemorrhage/stroke, sepsis, lower longitudinal oxygen saturation, readmission, smaller baseline aortic diameter, smaller baseline mitral valve z-score, and lower longitudinal weight. Each patient's predicted mortality trajectory varied as risk factors occurred over time. Groups with qualitatively similar mortality trajectories were noted. Conclusions: Risk of death post-Norwood is dynamic and most frequently associated with time-related postoperative events and measures, rather than baseline characteristics. Dynamic predicted mortality trajectories for individuals and their visualization represent a paradigm shift from population-derived insights to precision medicine at the patient level.

Hybrid palliation versus nonhybrid management for a multi-institutional cohort of infants with critical left heart obstruction.

OBJECTIVE: To compare patient characteristics and overall survival for infants with critical left heart obstruction after hybrid palliation (bilateral pulmonary artery banding with or without ductal stenting) versus nonhybrid management (eg, Norwood, primary transplantation, biventricular repair, or transcatheter/surgical aortic valvotomy). METHODS: From 2005 to 2019, 1045 infants in the Congenital Heart Surgeons' Society critical left heart obstruction cohort underwent interventions across 28 institutions. Using a balancing score propensity analysis, 214 infants who underwent hybrid palliation and 831 infants who underwent nonhybrid management were proportionately matched regarding variables significantly associated with mortality and variables noted to significantly differ between groups. Overall survival between the 2 groups was adjusted by applying balancing scores to nonparametric estimates. RESULTS: Compared with the nonhybrid management group, infants who underwent hybrid palliation had lower birth weight, smaller gestational age, and higher prevalence of in-utero interventions, noncardiac comorbidities, preoperative mechanical ventilation, absent interatrial communication, and moderate or severe mitral valve stenosis (all P values < .03). Unadjusted 12-year survival after hybrid palliation and nonhybrid management, was 55% versus 69%, respectively. After matching, 12-year survival after hybrid palliation versus nonhybrid management was 58% versus 63%, respectively (P = .37). Among matched infants born weighing <2.5 kg, 2-year survival after hybrid palliation versus nonhybrid management was 37% versus 51%, respectively (P = .22). CONCLUSIONS: Infants born with critical left heart obstruction who undergo hybrid palliation have more high-risk characteristics and anatomy versus infants who undergo nonhybrid management. Nonetheless, after adjustment, there was no significant difference in 12-year survival after hybrid palliation versus nonhybrid management. Mortality remains high, and hybrid palliation confers no survival advantage, even for lower-birth-weight infants.

Norwood operation versus comprehensive stage II after bilateral pulmonary artery banding palliation for infants with critical left heart obstruction.

OBJECTIVE: To determine patient characteristics and outcomes after Norwood versus comprehensive stage II (COMPSII) for infants with critical left heart obstruction who had prior hybrid palliation (bilateral pulmonary artery banding ± ductal stent). METHODS: From 23 Congenital Heart Surgeons' Society institutions (2005-2020), 138 infants underwent hybrid palliation followed by either Norwood (n = 73, 53%) or COMPSII (n = 65). Baseline characteristics were compared between Norwood and COMPSII groups. Parametric hazard model with competing risk methodology was used to determine risk and factors associated with outcomes of Fontan, transplantation, or death. RESULTS: Infants who underwent Norwood versus COMPSII had a higher prevalence of prematurity (26% vs 14%, P = .08), lower birth weight (median 2.8 vs 3.2 kg, P < .01) and less frequent ductal stenting (37% vs 99%; P < .01). Norwood was performed at a median age of 44 days and median weight of 3.5 kg, versus COMPSII at 162 days and 6.0 kg (both P < .01). Median follow-up was 6.5 years. At 5 years after Norwood and COMPSII, respectively; 50% versus 68% had Fontan (P = .16), 3% versus 5% had transplantation (P = .70), 40% versus 15% died (P = .10), and 7% versus 11% are alive without transition, respectively. For factors associated with either mortality or Fontan, only preoperative mechanical ventilation occurred more frequently in the Norwood group. CONCLUSIONS: Higher prevalence of prematurity, lower birth weight, and other patient-related characteristics in the Norwood versus COMPSII groups may influence differences in outcomes that were not statistically significant for this limited risk-adjusted cohort. The clinical decision regarding Norwood versus COMPSII after initial hybrid palliation remains challenging.

Toward More Granular Guidelines in AAOCA: Associating Anatomical Details With Specific Surgical Strategies.

Patients with anomalous aortic origin of a coronary artery (AAOCA) require imaging to clarify the multiple potential anatomic sites of obstruction (fixed or dynamic). Once repaired, the pathway of blood to the myocardium must not encounter: (1) intrinsic ostial stenosis, (2) obstruction from compression or distortion near the commissure or the intercoronary pillar, (3) stenosis where the artery exits the aortic wall (due to an acutely angled "take-off"), (4) compression due to a pathway between the great vessels, (5) stenosis or compression along an intramural course, or (6) compression due to an intramuscular (intraseptal/intraconal) course. Detailed anatomic evaluation of each of these locations allows the surgeon to select an appropriate repair strategy, and each of these abnormal anatomic features should be "matched" with a particular surgical correction. We speculate that the most common surgical repair, unroofing with or without tacking, is often inadequate, as in isolation, it may not allow for correction with a large orifice from the appropriate sinus, without an interarterial course. While the evidence base is insufficient to call these recommendations formal guidelines, these recommendations should serve as a basis for further validity testing, and ultimate evolution to more granular guidelines on AAOCA management.

Persistent Hypoxia After Blunt Thoracic Trauma due to Flail Tricuspid Valve Leaflet and Patent Foramen Ovale.

Structural cardiac injury after blunt trauma is uncommon but usually life-threatening. While tricuspid injury is very rare and potentially lethal, the right heart can accommodate larger volumes and higher pressures in acute tricuspid insufficiency and facilitate initial stabilization prior to definitive valvular repair. ECMO may be used to ameliorate resulting right heart failure. The traumatic force required to cause cardiac structural injury is also associated with pulmonary complications related to pneumothorax, hemothorax, effusion, acute pain secondary to rib fractures, and pulmonary contusions causing hypoxia. We present an unusual case of hypoxia in a trauma patient caused by acute tricuspid regurgitation with pre-existing patent foramen ovale.

Mycotic Pseudoaneurysm: Rare Complication of a Norwood/Sano Graft Stump.

The Sano variant of the stage 1 Norwood procedure is commonly performed as initial palliation for hypoplastic left heart syndrome. We present a case of a 2-year-old who developed a mycotic pseudoaneurysm of the Sano graft and discuss the importance of imaging and operative management of this rare presentation. Localization and full description of the lesion require compulsive, often multimodality imaging.

Congenital Left Main Coronary Atresia: Rare Cause of Sudden Cardiac Arrest.

A 13-month-old male sustained cardiac arrest under general anesthesia and was found to have left main coronary artery atresia with collateralization from the right coronary artery. After protracted recovery, the patient underwent coronary ostioplasty. Postoperative imaging confirmed patency of the newly established artery without stenosis. At 12 months, no changes in the vessel were noted. Ventricular function remains mildly decreased and stable.

Joint programmes in paediatric cardiac surgery: an update and descriptive analysis.

OBJECTIVE: Joint programmes are an alternative model that may aid in improving congenital cardiac surgery outcomes while avoiding the potential resource and accessibility challenges that could result from regionalisation. This study aims to characterise current joint programmes, identify factors that are associated with joint programme success and failure, and gauge attitudes within the profession regarding joint programmes as an alternative. METHODS: A multiple choice survey with 23 standard questions for all programmes and additional 42 additional questions for each participant hospital in a joint programme was addressed to paediatric cardiac surgeons in the United States of America. Questions were designed to qualitatively and quantitatively characterise congenital cardiac surgery joint programmes. RESULTS: Of the 34 unique congenital cardiac surgery programmes identified in this survey, 14 have participated in a joint programme and 50% of those joint programmes existed for more than 10 years. Most joint programmes (86%) participate or participated in a model where the hospital participants are engaged in a "mother-daughter" relationship in both perception and case volume distribution. In three out of four defunct joint programmes, there were case complexity limitations placed on partner institutions, but the now independent partner institutions operate with no limitation on complexity. Most (71%) hospital participants in a joint programme felt that the joint programme produced better outcomes than two separate programmes; however, among those who participate or have participated in a joint programme, only 18% felt that joint programmes were the optimal model for delivery of congenital cardiac surgical care.

Passive high-frequency microrheology of blood.

Indicative of various pathologies, blood properties are under intense scrutiny. The hemorheological characteristics are traditionally gauged by bulk, low-frequency indicators that average out critical information about the complex, multi-scale, and multi-component structure. In particular, one cannot discriminate between the erythrocytes contribution to global rheology and the impact of plasma. Nevertheless, in their fast stochastic movement, before they encounter each other, the erythrocytes probe the subtle viscoelasticity of their protein-rich environment. Thus, if these short time scales can be resolved experimentally, the plasma properties could be determined without having to separate the blood components; the blood is practically testing itself. This microrheological description of blood plasma provides a direct link between the composition of whole blood and its coagulability status. We present a parametric model for the viscoelasticity of plasma, which is probed by the erythrocytes over frequency ranges of kilohertz in a picoliter-sized volume. The model is validated both in vitro, using artificial hemo-systems where the composition is controlled, as well as on whole blood where continuous measurements provide real-time information. We also discuss the possibility of using this passive microrheology as an in vivo assay for clinically relevant situations where the blood clotting condition must be observed and managed continuously for diagnosis or during therapeutic procedures at different stages of hemostatic and thrombotic processes.

Factors associated with mortality or transplantation versus Fontan completion after cavopulmonary shunt for patients with tricuspid atresia.

OBJECTIVE: Tricuspid atresia with normally related great vessels (TA) is considered the optimal substrate for the Fontan pathway. The factors associated with death or transplantation after cavopulmonary shunt (CPS) are underappreciated. We aimed to determine factors associated with CPS-Fontan interstage death/transplantation versus transition to Fontan in TA. METHODS: A total of 417 infants younger than 3 months of age with TA were enrolled (January 1999 to February 2020) from 40 institutions into the Congenital Heart Surgeons' Society TA cohort. Parametric competing risk methodology was used to determine factors associated with the competing end points of death/transplantation without Fontan completion, and transition to Fontan. RESULTS: CPS was performed in 382 patients with TA; of those, 5% died or underwent transplantation without transition to Fontan and 91% transitioned to Fontan by 5 years after CPS. Prenatal diagnosis (hazard ratio [HR], 0.74; P < .001) and pulmonary artery band (PAB) at CPS (HR, 0.50; P < .001) were negatively associated with Fontan completion. Preoperative moderate or greater mitral valve regurgitation (HR, 3.0; P < .001), concomitant mitral valve repair (HR, 11.0; P < .001), PAB at CPS (HR, 3.0; P < .001), postoperative superior vena cava interventions (HR, 9.0; P < .001), and CPS takedown (HR, 40.0; P < .001) were associated with death/transplantation. CONCLUSIONS: The mortality rate after CPS in patients with TA is notable. Those with preoperative mitral valve regurgitation remain a high-risk group. PAB at the time of CPS being associated with both increased risk of death and decreased Fontan completion may represent a deleterious effect of antegrade pulmonary blood flow in the CPS circulation.

Time-Related Risk of Pulmonary Conduit Re-replacement: A Congenital Heart Surgeons' Society Study.

BACKGROUND: Patients receiving a right ventricle to pulmonary artery conduit (PC) in infancy will require successive procedures or replacements, each with variable longevity. We sought to identify factors associated with time-related risk of a subsequent surgical replacement (PC3) or transcatheter pulmonary valve insertion (TPVI) after a second surgically placed PC (PC2). METHODS: From 2002 to 2016, 630 patients from 29 Congenital Heart Surgeons' Society member institutions survived to discharge after initial valved PC insertion (PC1) at age ≤ 2 years. Of those, 355 underwent surgical replacement (PC2) of that initial conduit. Competing risk methodology and multiphase parametric hazard analyses were used to identify factors associated with time-related risk of PC3 or TPVI. RESULTS: Of 355 PC2 patients (median follow-up, 5.3 years), 65 underwent PC3 and 41 TPVI. Factors at PC2 associated with increased time-related risk of PC3 were smaller PC2 Z score (hazard ratio [HR] 1.6, P < .001), concomitant aortic valve intervention (HR 7.6, P = .009), aortic allograft (HR 2.2, P = .008), younger age (HR 1.4, P < .001), and larger Z score of PC1 (HR 1.2, P = .04). Factors at PC2 associated with increased time-related risk of TPVI were aortic allograft (HR: 3.3, P = .006), porcine unstented conduit (HR 4.7, P < .001), and older age (HR 2.3, P = .01). CONCLUSIONS: Aortic allograft as PC2 was associated with increased time-related risk of both PC3 and TPVI. Surgeons may reduce risk of these subsequent procedures by not selecting an aortic homograft at PC2, and by oversizing the conduit when anatomically feasible.