Anomalous Aortic Origin of a Coronary Artery

BACKGROUND

Although anomalous aortic origin of a coronary artery (AAOCA) is associated with risk of sudden cardiac arrest (SCA), there is a spectrum of disease, with the appropriate management for many remaining unclear. Increasing data warrant review for an updated perspective on management.

METHODS

A panel of congenital cardiac surgeons, cardiologists, and imaging practitioners reviewed the current literature related to AAOCA and its management. Survey of relevant publications from 2010 to the present in PubMed was performed.

RESULTS

The prevalence of AAOCA is 0.4% to 0.8%. Anomalous left coronary artery is 3 to 8 times less common than anomalous right coronary, but carries a much higher risk of SCA. Nevertheless, anomalous right coronary is not completely benign; 10% demonstrate ischemia, and it remains an important cause of SCA. Decision-making regarding which patients should be recommended for surgical intervention includes determining anatomic features associated with ischemia, evidence of ischemia on provocative testing, and concerning cardiovascular symptoms. Ischemia testing continues to prove challenging with low sensitivity and specificity, but the utility of new modalities is an active area of research. Surgical interventions focus on creating an unobstructed path for blood flow and choosing the appropriate surgical technique given the anatomy to accomplish this. Nontrivial morbidity has been reported with surgery, including new-onset ischemia.

CONCLUSIONS

A proportion of patients with AAOCA demonstrate features and ischemia that warrant surgical intervention. Continued work remains to improve the ability to detect inducible ischemia, to risk stratify these patients, and to provide guidance in terms of which patients warrant surgical intervention.

Contemporary Applications and Outcomes of Pulmonary Artery Banding: An Analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database

BACKGROUND

Pulmonary artery banding (PAB) in isolation or combined with a congenital cardiac surgical procedure is common and has important mortality. We aimed to determine patient characteristics, clinical outcomes, variation in clinical outcomes by diagnoses, and center variation in PAB use.

METHODS

Using The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS CHSD), this study evaluated outcomes of patients undergoing PAB across diagnoses, participating centers, and additional procedures. Patients were identified by procedure and diagnosis codes from 2016 to 2019. We separated patients into groups of main and bilateral PAB and described their outcomes, focusing on patients with main PAB.

RESULTS

This study identified 3367 PAB procedures from 2016 to 2019 (3% of all STS CHSD cardiovascular cases during this period): 2677 main PAB, 690 bilateral PAB. Operative mortality was 8% after main PAB and 26% after bilateral PAB. There was significant variation in use of main PAB by center, with 115 centers performing at least 1 main PAB procedure (range, 1-134; Q1-Q3, 8-33). For patients with main PAB, there were substantial differences in mortality, depending on timing of main PAB relative to other procedures. The highest operative mortality (25%; P < .0001) was in patients who underwent main PAB after another separate procedure during their admission, with extracorporeal membrane oxygenation being the most frequent preceding procedure.

CONCLUSIONS

PAB is a frequently used congenital cardiac procedure with high mortality and variation in use across centers. Outcomes vary widely by banding type and patient diagnosis. Main PAB after cardiac surgical procedures, especially extracorporeal membrane oxygenation, is associated with very high operative mortality.

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.

Outcomes After Hybrid Palliation for Infants With Critical Left Heart Obstruction

BACKGROUND

Hybrid palliation (bilateral pulmonary artery banding with or without ductal stenting) is an initial management strategy for infants with critical left heart obstruction and serves as palliation until subsequent operations are pursued.

OBJECTIVES

This study sought to determine patient characteristics and factors associated with subsequent outcomes for infants who underwent hybrid palliation.

METHODS

From 2005 to 2019, 214 of 1,236 prospectively enrolled infants within the Congenital Heart Surgeons' Society's critical left heart obstruction cohort underwent hybrid palliation across 24 institutions. Multivariable hazard modeling with competing risk methodology was performed to determine risk and factors associated with outcomes of biventricular repair, Fontan procedure, transplantation, or death.

RESULTS

Preoperative comorbidities (eg, prematurity, low birth weight, genetic syndrome) were identified in 70% of infants (150 of 214). Median follow-up was 7 years, ranging up to 17 years. Overall 12-year survival was 55%. At 5 years after hybrid palliation, 9% had biventricular repair, 36% had Fontan procedure, 12% had transplantation, 35% died without surgical endpoints, and 8% were alive without an endpoint. Factors associated with transplantation were absence of ductal stent, older age, absent interatrial communication, smaller aortic root size, larger tricuspid valve area z-score, and larger left ventricular volume. Factors associated with death were low birth weight, concomitant genetic syndrome, cardiopulmonary bypass use during hybrid palliation, moderate to severe tricuspid valve regurgitation, and smaller ascending aortic size.

CONCLUSIONS

Mortality remains high after hybrid palliation for infants with critical left heart obstruction. Nonetheless, hybrid palliation may facilitate biventricular repair for some infants and for others may serve as stabilization for intended functional univentricular palliation or primary transplantation.

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].

The Congenital Heart Surgeons' Society Kirklin/Ashburn Fellowship: The Fellows' Perspective

Since its establishment in 2001, the Congenital Heart Surgeons' Society John W. Kirklin/David Ashburn Fellowship has contributed substantially to the field of congenital heart surgery research while simultaneously training the next generation of surgeon- scientists. To date, ten fellows (and counting) have successfully completed this rigorous training, producing over 40 published articles focused on longitudinal outcomes from the various Congenital Heart Surgeons' Society cohorts. As the Kirklin/Ashburn Fellowship expands and additional fellows matriculate, its legacy, the network of support, and the contribution to congenital heart surgery research will undoubtedly hold strong.

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.

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.

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.

Outcomes of expanded polytetrafluoroethylene pericardial membrane implantation in left ventricular assist device explantation and heart transplantation

OBJECTIVES

Redo sternotomy and explantation of left ventricular assist devices (LVAD) for heart transplantation (HT) involve prolonged dissection, potential injury to mediastinal structures and/or bleeding. Our study compared a complete expanded polytetrafluoroethylene (ePTFE) wrap versus minimal or no ePTFE during LVAD implantation, on outcomes of subsequent HT.

METHODS

Between July 2005 and July 2018, 84 patients underwent a LVAD implant and later underwent HT. Thirty patients received a complete ePTFE wrap during LVAD implantation (Group 1), and 54 patients received either a sheet of ePTFE placed in the anterior mediastinum or no ePTFE (Group 2).

RESULTS

Baseline characteristics were similar between Groups 1 and 2. Surgeons reported subjective improvements in speed, predictability, and safety of dissection with complete ePTFE compared with minimal or no ePTFE. Time from incision to initiation of cardiopulmonary bypass (CPB) were similar between groups (97 ± 38 vs. 89 ± 29 min, p = .3). Injury to mediastinal structures during the dissection was similar between groups (10% vs. 11%, p > .9). While surgeons reported less intraoperative bleeding in Group 1 (43% vs. 61%), this trend did not reach significance (p = .1). In-hospital mortality, intensive care unit length of stay and hospital length of stay were similar between both groups.

CONCLUSIONS

In patients undergoing LVAD explant-HT, there was a trend toward reduced surgeon reported intraoperative bleeding with ePTFE placement. Despite qualitatively reported greater ease and speed of mediastinal dissection with ePTFE membrane placement, time to initiation of CPB did not differ, likely because surgeons remained cautious, allowing extra time for unanticipated difficulties.

An integration engineering framework for machine learning in healthcare

Background and Objectives

Machine Learning offers opportunities to improve patient outcomes, team performance, and reduce healthcare costs. Yet only a small fraction of all Machine Learning models for health care have been successfully integrated into the clinical space. There are no current guidelines for clinical model integration, leading to waste, unnecessary costs, patient harm, and decreases in efficiency when improperly implemented. Systems engineering is widely used in industry to achieve an integrated system of systems through an interprofessional collaborative approach to system design, development, and integration. We propose a framework based on systems engineering to guide the development and integration of Machine Learning models in healthcare.

Methods

Applied systems engineering, software engineering and health care Machine Learning software development practices were reviewed and critically appraised to establish an understanding of limitations and challenges within these domains. Principles of systems engineering were used to develop solutions to address the identified problems. The framework was then harmonized with the Machine Learning software development process to create a systems engineering-based Machine Learning software development approach in the healthcare domain.

Results

We present an integration framework for healthcare Artificial Intelligence that considers the entirety of this system of systems. Our proposed framework utilizes a combined software and integration engineering approach and consists of four phases: (1) Inception, (2) Preparation, (3) Development, and (4) Integration. During each phase, we present specific elements for consideration in each of the three domains of integration: The Human, The Technical System, and The Environment. There are also elements that are considered in the interactions between these domains.

Conclusion

Clinical models are technical systems that need to be integrated into the existing system of systems in health care. A systems engineering approach to integration ensures appropriate elements are considered at each stage of model design to facilitate model integration. Our proposed framework is based on principles of systems engineering and can serve as a guide for model development, increasing the likelihood of successful Machine Learning translation and integration.

Anomalous aortic origin of a coronary artery: learning from the past to make advances in the future

PURPOSE OF REVIEW

To review anomalous aortic origin of a coronary artery (AAOCA) anatomy, prevalence, mechanism and risk of ischemia, presentation, evaluation, management, and future directions.

RECENT FINDINGS

Although most anatomic variants of AAOCA are benign, a small number are associated with increased risk of sudden death. A complete evaluation, including the use of advanced noninvasive imaging and provocative testing should be performed on nearly every patient with AAOCA. On the basis of recent studies, the ischemic risk appears to be greatest with a left anomalous coronary artery but an anomalous right coronary artery is not benign. Other risk factors include: a left anomalous coronary with an intramural course, high take-off, or slit-like orifice, and a right anomalous coronary with a longer intramural course. Exercise restriction is rarely recommended. Management primarily consists of nonoperative care, or surgical repair in those who are symptomatic or who have high-risk variants. Surgery itself continues to evolve; however, it is not benign, with a higher than expected chance of morbidity.

SUMMARY

Advances have been made over the past decade regarding management of patients with AAOCA; however, the mechanism of ischemia and ability to predict risk is still incompletely understood. Management decisions should be based on anatomy, results of investigations, and shared decision-making with patients and their families. Surgery may be recommended for those at higher risk and should be done at centers experienced in AAOCA surgery. Future research should be collaborative in order to share experiences and insights to help advance our understanding of risk and ultimately to improve patient management.

Association of atrial septal fenestration with outcomes after atrioventricular septal defect repair

OBJECTIVE

During repair of atrioventricular septal defect (AVSD), surgeons might leave an atrial level shunt when concerned about postoperative physiology, or as part of routine practice. However, the association of fenestration with outcomes is unclear. We sought to determine factors associated with mortality after biventricular repair of AVSD.

METHODS

We included 581 patients enrolled from 32 Congenital Heart Surgeons' Society institutions from January 1, 2012, to June 1, 2020 in the Congenital Heart Surgeons' Society AVSD cohort. Parametric multiphase hazard analysis was used to identify factors associated with mortality. A random effect model was used to account for possible intersite variability in mortality.

RESULTS

An atrial fenestration was placed during repair in 133/581 (23%) patients. Overall 5-year survival after repair was 91%. Patients who had fenestration had an 83% 5-year survival versus 93% for those not fenestrated (P < .001). Variables associated with mortality in multivariable hazard analysis included institutional diagnosis of ventricular unbalance (hazard ratio [HR], 2.7 [95% confidence interval (CI): 1.5-4.9]; P = .003), preoperative mechanical ventilation (HR, 4.1 [95% CI, 1.3-13.1]; P = .02), atrial fenestration (HR, 2.8 [95% CI, 1.5-4.9]; P < .001), and reoperation for ventricular septal defect (HR, 4.0 [95% CI, 1.3-13.1]; P = .002). There was no difference in measures of ventricular unbalance for comparisons of fenestrated with nonfenestrated patients. No significant interinstitution variability in mortality was observed on the basis of the random effect model (P = .7).

CONCLUSIONS

An atrial communication at biventricular repair of AVSD is associated with significantly reduced long-term survival after adjusting for other known associated factors, including unbalance. These findings might challenge the routine practice of fenestration.

Time-related risk of pulmonary conduit re-replacement: a Congenital Heart Surgeons' Society Study

BACKGROUND

Patients receiving a right ventricle-to-pulmonary artery conduit 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 had undergone 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 of 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<0.001), concomitant aortic valve intervention (HR 7.6, p=0.009), aortic allograft (HR 2.2, p=0.008), younger age (HR 1.4, p<0.001), and larger Z score of PC1 (HR 1.2, p=0.04). Factors at PC2 associated with increased time-related risk of TPVI were aortic allograft (HR: 3.3, p=0.006), porcine unstented conduit (HR 4.7, p<0.001), and older age (HR 2.3, p=0.01).

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.

Surgery for Anomalous Aortic Origin of Coronary Arteries: Technical Safeguards and Pitfalls

Anomalous aortic origin of a coronary artery (AAOCA) is reported as the second leading cause of sudden cardiac death in otherwise healthy young individuals. Several surgical studies have reported a shallow operative risk, describing repair as safe and effective with short or medium-term follow-up. However, surgical repair can also be associated with a high risk of complications. Numerous repair techniques have been described in the literature, but each technique's indications and limitations are often not well-understood or understated. Since explicit technical knowledge of the most appropriate surgical technique is highly desirable, we sought to thoroughly and clearly outline the safeguards and pitfalls of the most common surgical techniques used to repair AAOCA.

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.

How and When Should Tetralogy of Fallot be Palliated Prior to Complete Repair?

The controversy regarding the best or ideal surgical management of Tetralogy of Fallot (ToF) stems from the recognition of there being a spectrum of morphology and associated lesions, each of which require a different approach to achieve the three goals of minimizing mortality preserving right ventricular function long-term and minimizing reinterventions. A one-size-fits-all approach to ToF needs to be replaced by a considered and personalized approach in order to yield the best outcomes possible for individual patients. The great majority of patients with ToF undergo primary complete repair between age 3-9 months with excellent outcomes. However, the greatest challenge is the severely cyanotic neonates where primary repair is still associated with high mortality and reintervention rates. Risk factors are low weight and small/poorly developed pulmonary vasculature. High-risk neonates have better outcomes with palliation-but mortality is still high. Palliative interventions in the catherization lab are showing better outcomes than traditional BT shunt and the RVOT stent is emerging as potential game-changer. Primary neonatal repair is still recommended if weight >3 kg and Nakata >100 mm²/m². However, neonates with low weight, small pulmonary arteries or multiple comorbidities (including ToF/AVSD and anomalous LAD) may do better with a staged approach, There is good argument for RVOT stenting as a bridge to complete repair due to its stable circulation without diastolic run off and volume loading of the circulation, and its potential to allow branch PA growth.

Bleeding risk associated with combination thromboprophylaxis therapy is low for patients with coronary artery aneurysms after Kawasaki disease

BACKGROUND

Kawasaki disease (KD) may lead to coronary artery aneurysms (CAA) with potential for thrombosis. We aimed to determine the bleeding risk during thromboprophylaxis regimens with dual and triple therapy.

METHODS

KD patients with medium to large CAAs receiving combination thromboprophylaxis therapy (dual or triple therapy with acetylsalicylic acid (ASA), clopidogrel, low molecular weight heparin (LMWH) or warfarin) were reviewed (1979-2017). Treatment periods <30 days were excluded. Bleeding events were classified using the Bleeding Academic Research Consortium (BARC) Score. The incidence of bleeding events per patient year of exposure was determined for each regimen.

RESULTS

n = 98 of 3022 KD (23 females:75 males) were included. Median age at diagnosis was 2.6 years (IQR: 0.6-6.2), median maximum CAA z-score was 18.0 (range: 5-65.5, IQR: 10.8-28.0, m = 6) and median follow-up duration was 6.5 years (IQR: 2.5-20.2). The incidence of type ≥2 bleeds per patient-year for each regimen was 0 (ASA + clopidogrel+LMWH), 0.03 (ASA + clopidogrel), 0.06 (ASA + warfarin), 0.06 (ASA + clopidogrel+warfarin), and 0.1 (ASA + LMWH) in ascending order. 31 bleeding events requiring medical attention (type ≥2) occurred in 30 patients (median age 7.8 years). Of the 17 type ≥2 bleeds on warfarin with an International Normalised Ratio (INR) available, 13 occurred with an INR >3. For patients receiving triple therapy (dual antiplatelet with anticoagulant), there were 57 bleeding events over 20 treatment periods.

CONCLUSIONS

The overall bleeding risk was low in KD patients receiving combination thromboprophylaxis, and not significantly different across all regimens. Type ≥2 bleeding events that occurred on warfarin were most frequently associated with high INR values.

Negative Impact of Obesity on Ventricular Size and Function and Exercise Performance in Children and Adolescents With Repaired Tetralogy of Fallot

BACKGROUND

Up to 25% of children with congenital heart disease are obese, which may have negative physiologic consequences for patients with repaired tetralogy of Fallot (rTOF).

METHODS

Patients with rTOF who underwent cardiac magnetic resonance (CMR) imaging and cardiopulmonary exercise testing from 2007 to 2018 were reviewed. Complex rTOF patients were excluded. Obese patients (body mass index [BMI] ≥ 95th percentile) were compared with normal-weight patients (BMI < 85th percentile). CMR data were indexed to actual body surface area (aBSA), height, and BSA assuming ideal body weight (iBSA).

RESULTS

We compared 32 obese patients matched with 64 normal-weight patients. Obese vs normal-weight patients had significantly lower right (RV; median 45% [interquartile range 42%-48%] vs 52% [47%-55%]; P < 0.0001) and left (LV; 52% [47%-56%] vs 56% [54%-60%]; P < 0.0001) ventricular ejection fractions (EFs). There were no statistically significant differences regarding aBSA-indexed volumes of the RV or LV at either end-diastole (EDV) or end-systole (ESV). However, when indexed to either height or iBSA, obese patients had significantly greater RVEDV and LVEDV, greater LV mass, and higher RV and LV stroke volumes. Obese patients had lower peak oxygen consumption and oxygen consumption at anaerobic threshold. These results did not change after adjusting for degree of pulmonary regurgitation.

CONCLUSIONS

Obesity is associated with increased biventricular size, decreased biventricular EFs, and impaired exercise performance after rTOF. These data suggest a potential role for cardiac rehabilitation for weight management and to optimize fitness.

A practical approach to storage and retrieval of high-frequency physiological signals

OBJECTIVE

Storage of physiological waveform data for retrospective analysis presents significant challenges. Resultant data can be very large, and therefore becomes expensive to store and complicated to manage. Traditional database approaches are not appropriate for large scale storage of physiological waveforms. Our goal was to apply modern time series compression and indexing techniques to the problem of physiological waveform storage and retrieval.

APPROACH

We deployed a vendor-agnostic data collection system and developed domain-specific compression approaches that allowed long term storage of physiological waveform data and other associated clinical and medical device data. The database (called AtriumDB) also facilitates rapid retrieval of retrospective data for high-performance computing and machine learning applications.

MAIN RESULTS

A prototype system has been recording data in a 42-bed pediatric critical care unit at The Hospital for Sick Children in Toronto, Ontario since February 2016. As of December 2019, the database contains over 720,000 patient-hours of data collected from over 5300 patients, all with complete waveform capture. One year of full resolution physiological waveform storage from this 42-bed unit can be losslessly compressed and stored in less than 300 GB of disk space. Retrospective data can be delivered to analytical applications at a rate of up to 50 million time-value pairs per second.

SIGNIFICANCE

Stored data are not pre-processed or filtered. Having access to a large retrospective dataset with realistic artefacts lends itself to the process of anomaly discovery and understanding. Retrospective data can be replayed to simulate a realistic streaming data environment where analytical tools can be rapidly tested at scale.

Outcomes after anomalous aortic origin of a coronary artery repair: A Congenital Heart Surgeons' Society Study

OBJECTIVES

It remains unclear when sudden cardiac event risk outweighs surgical risk for patients with anomalous aortic origin of a coronary artery. The Congenital Heart Surgeons' Society sought to characterize the surgical risks by determining the techniques, complications, and outcomes of repair.

METHODS

Between January 2000 and September 2018, 682 patients with anomalous aortic origin of a coronary artery aged 30 years or less were enrolled. Demographic, morphologic, operative, imaging, and ischemia-related data were analyzed.

RESULTS

There were 395 of 682 (57%) surgical patients (45 centers, median follow-up 2.8 years). In addition to primary repair (87% unroofing, 26% commissural manipulation), 13 patients had 15 coronary-related reoperations. Of 358 patients with pre/postoperative aortic insufficiency assessment, 27 (8%) developed new mild or greater aortic insufficiency postoperatively, and 7 (2%) developed new moderate or greater aortic insufficiency. Freedom from mild aortic insufficiency differed in those with versus without commissural manipulation (85%/91% at 6 months, 83%/90% at 1 year, and 77%/88% at 3 years, respectively) (P = .05). Of 347 patients with preoperative/postoperative ejection fraction, 6 (2%) developed new abnormal ejection fraction (<50%) within 30 days of surgery which persisted. Although 64 of 395 patients (16%) had preoperative ischemia, after surgery 51 of 64 patients (80%) no longer had ischemia (13 = new postoperative ischemia, P < .0001). Four patients died postoperatively (preoperatively 2 asymptomatic, 1 symptomatic, 1 in extremis). Composite surgical adverse event rates were 7% to 13% in the entire cohort (increasing/decreasing by presentation/anatomy/repair strategy).

CONCLUSIONS

Anomalous aortic origin of a coronary artery surgery may relieve ischemia with low mortality; however, it can result in a variety of important morbidities, varying by the group evaluated. Strategies avoiding commissural manipulation may decrease the risk of developing aortic insufficiency. Understanding these risks should inform surgical decision-making and support the need for standardized assessment and management.

Extracorporeal membrane oxygenation as a novel management strategy for interventricular septal hematoma following ventricular septal defect repair

OBJECTIVES

Interventricular septal hematoma (IVSH) is a rare complication, which may result from ventricular septal defect (VSD) repair. IVSH can result in conduction and/or hemodynamic abnormalities related to impaired ventricular filling or outflow tract obstruction. We report the novel use of extracorporeal membrane oxygenation (ECMO) for management.

METHODS

Echocardiography reports (January 1980 to December 2016) were searched for the term "hematoma" in our institutional database and reviewed to determine appropriate cases. Charts and imaging (reports) data were abstracted. All intraoperative and select postoperative echocardiograms were reread by a pediatric cardiologist.

RESULTS

N = 12 patients with IVSH. Mean age and weight at surgery were 59 ± 41 days and 3.4 (2.9-5.1) kg, respectively, while the most frequent diagnosis was tetralogy of Fallot. Although all patients had intraoperative transesophageal echocardiography (TEE), only 55% (6 of 11, missing [m] = 1) of IVSH were discovered intraoperatively. Of the 5 patients not discovered intraoperatively (m = 1), IVSH was postoperatively detected secondary to arrhythmia/decompensation by echocardiogram 10.1 ± 7.9 hours postoperatively. Five patients (42%) were managed with ECMO (1 unable to separate from bypass). Overall mortality was 33%. For patients in whom ECMO was used, 2 of 5 (40%) survived. Mean time to IVSH resolution in all survivors was 20 ± 185 days.

CONCLUSIONS

IVSH from VSD repair can result in clinical decompensation and mortality. This may relate to the high proportion missed intraoperatively. ECMO should be considered an important modality, which can allow for IVSH resolution. However, considerations must be made to allow for appropriate anticoagulation to avoid hematoma expansion and repeat imaging during ECMO to continually assess the interventricular septum.

Pulmonary artery banding in complete atrioventricular septal defect

OBJECTIVES

To analyze outcomes after pulmonary artery banding (PAB) in complete atrioventricular septal defect (AVSD), with a focus on surgical pathway outcome and timing, survival, and atrioventricular valve function.

METHODS

PAB was performed in 50 of 474 infants (11%) from 28 institutions between 2012 and 2018 at a median age of 1.1 months. The median duration of follow-up was 2.1 years. Atrioventricular valve function was assessed by review of pre-PAB and predischarge echocardiograms (median, 9 days postoperatively). Competing-risks methodology was used to analyze the risks for biventricular repair, univentricular repair, and death.

RESULTS

At 2 years, the proportions of patients who underwent biventricular repair, univentricular repair, and death were 68%, 13%, and 12%, respectively, with 8% awaiting definitive repair. After PAB, atrioventricular valve regurgitation decreased in 14 infants and increased in 10, but the distribution of regurgitation severity did not change significantly in the total cohort or subgroups. The intended management plan at PAB was deferred biventricular/univentricular decision (23 infants), 2-stage biventricular repair (24 infants), and univentricular repair (3 infants). Among the 24 infants intended for biventricular repair, 23 achieved biventricular repair and 1 died before repair. Survival at 4 years after biventricular repair among patients with previous PAB (93%) was similar to the 4-year survival of the patients who underwent primary biventricular repair (91%; n = 333).

CONCLUSIONS

PAB is a successful strategy in complete AVSD to bridge to biventricular repair and has similar post-biventricular repair survival to primary biventricular repair. Changes in atrioventricular valve regurgitation after PAB were variable.

Late Survival and Patient-Perceived Health Status of the Congenital Heart Surgeons' Society dextro-Transposition of the Great Arteries Cohort

BACKGROUND

Improved survival for patients with dextro-transposition of the great arteries (d-TGA) has led to an increased focus on functional health status (FHS). We assessed late survival and patient-perceived FHS for repaired TGA patients.

METHODS

From 1985-1990, 830 neonates admitted to 24 Congenital Heart Surgeons' Society (CHSS) institutions with d-TGA underwent repair, including 516 arterial switch, 110 Mustard, 175 Senning, and 29 Rastelli operations. Median follow-up was 24.0 years (range, 0-32.7 years). We performed multiphase parametric hazard analysis for death after repair. Patients completed Pediatric Quality of Life Inventory (PedsQL) Core Scales and Cardiac Module Adult Forms. Patient and operative factors and CHSS General Questionnaire responses were analyzed for association with FHS using multiple linear regression.

RESULTS

Survival at 30 years after repair was arterial switch, 80% ± 2%; Mustard, 81% ± 5%; Senning, 70% ± 4%; and Rastelli, 86% ± 8%. The arterial switch had the lowest hazard for late death. TGA patients reported FHS similar to a healthy population in all domains except physical health (lower scores). Symptoms, including chest pain and fainting, and having a pacemaker were associated with lower, and being employed with higher, self-reported physical health. Arterial switch patients reported higher FHS than the atrial switch patients in all domains.

CONCLUSIONS

Arterial switch patients have a lower risk of premature death and better FHS than those with an atrial switch. Increased surveillance in atrial switch patients is warranted because of their increased risk of late death. Presence of symptoms, pacemaker, and lack of employment are associated with reduced FHS.

Self-reported functional health status following interrupted aortic arch repair: A Congenital Heart Surgeons' Society Study

OBJECTIVES

Improved survival after congenital heart surgery has led to interest in functional health status. We sought to identify factors associated with self-reported functional health status in adolescents and young adults with repaired interrupted aortic arch.

METHODS

Follow-up of survivors (aged 13-24 years) from a 1987 to 1997 inception cohort of neonates included completion of functional health status questionnaires (Child Health Questionnaire-CF87 [age <18 years, n = 51] or the Short Form [SF]-36 [age ≥18 years, n = 66]) and another about 22q11 deletion syndrome (22q11DS) features (n = 141). Factors associated with functional health status domains were determined using multivariable linear regression analysis.

RESULTS

Domain scores of respondents were significantly greater than norms in 2 of 9 Child Health Questionnaire-CF87 and 4 of 10 SF-36 domains and only lower in the physical functioning domain of the SF-36. Factors most commonly associated with lower scores included those suggestive of 22q11DS (low calcium levels, recurrent childhood infections, genetic testing/diagnosis, abnormal facial features, hearing deficits), the presence of self-reported behavioral and mental health problems, and a greater number of procedures. Factors explained between 10% and 70% of domain score variability (R² = 0.10-0.70, adj-R² = 0.09-0.66). Of note, morphology and repair type had a minor contribution.

CONCLUSIONS

Morbidities associated with 22q11DS, psychosocial issues, and recurrent medical issues affect functional health status more than initial morphology and repair in this population. Nonetheless, these patients largely perceive themselves as better than their peers. This demonstrates the chronic nature of interrupted aortic arch and suggests the need for strategies to decrease reinterventions and for evaluation of mental health and genetic issues to manage associated deteriorations.

Comparison of 3D Echocardiogram-Derived 3D Printed Valve Models to Molded Models for Simulated Repair of Pediatric Atrioventricular Valves

Mastering the technical skills required to perform pediatric cardiac valve surgery is challenging in part due to limited opportunity for practice. Transformation of 3D echocardiographic (echo) images of congenitally abnormal heart valves to realistic physical models could allow patient-specific simulation of surgical valve repair. We compared materials, processes, and costs for 3D printing and molding of patient-specific models for visualization and surgical simulation of congenitally abnormal heart valves. Pediatric atrioventricular valves (mitral, tricuspid, and common atrioventricular valve) were modeled from transthoracic 3D echo images using semi-automated methods implemented as custom modules in 3D Slicer. Valve models were then both 3D printed in soft materials and molded in silicone using 3D printed "negative" molds. Using pre-defined assessment criteria, valve models were evaluated by congenital cardiac surgeons to determine suitability for simulation. Surgeon assessment indicated that the molded valves had superior material properties for the purposes of simulation compared to directly printed valves (p < 0.01). Patient-specific, 3D echo-derived molded valves are a step toward realistic simulation of complex valve repairs but require more time and labor to create than directly printed models. Patient-specific simulation of valve repair in children using such models may be useful for surgical training and simulation of complex congenital cases.

TOUGH Syndrome: A Report of an Early Immediate Postoperative Cause of Aortocoronary Graft Occlusion

Aortocoronary artery bypass grafts are time tested to be effective definitive therapy of symptomatic coronary artery disease since their inception in the 1960s. Over the years, multiple factors have affected the long-term outcome and patency rates of vein grafts. These can be divided into acute, subacute, and delayed categories. The most common causes, respectively, are thrombosis, intimal hyperplasia, and accelerated atherosclerosis. Numerous studies have analyzed postoperative angiographic images to evaluate these phenomena, and medical therapies have been instituted to prevent occlusion of these grafts. Besides these pathologic mechanisms, a surgeon and the surgeon's team must be aware of potential early reversible causes of coronary occlusion that are most often mechanical in nature. Graft kinking and external compression are known adverse events that may require early intervention to correct the underlying cause of graft occlusion. Here we present a case of graft occlusion by what we refer to as TOUGH syndrome: Thoracostomy tube Occluding Underlying coronary Graft causing Harm.

Balancing pulmonary blood flow: Theory, in vitro measurements, and clinical correlation of systemic-to-pulmonary shunt banding

BACKGROUND

Size mismatch between body and a systemic-to-pulmonary shunt can result in excessive pulmonary blood flow, compromising systemic oxygen delivery. Previously reported techniques to mechanically restrict shunt flow lack precision and reproducibility. We developed a formula for shunt banding and assessed its efficacy and reproducibility by in vitro and clinical measurements.

METHODS

Formulas to determine diameter reduction, length of banding, and effect on the ratio of pulmonary blood flow (Q_p) to systemic blood flow (Q_s) were established. In vitro measurements of different shunt grafts were performed. Results were compared with calculations and clinical data. Clinical outcome was retrospectively assessed in all patients (n = 8) who underwent a shunt banding procedure at our institution between 2008 and 2012.

RESULTS

Our formulas can adequately predict the length of the band based on the desired diameter and shunt type or on the Q_p:Q_s mismatch. In vitro measurements correlated with the manufacturer's specifications in small shunts (≤5 mm diameter; 0.45 mm mean wall thickness). The calculated diameters of these shunts were closely correlated with in vitro measurements (r = 0.953; P = .001). Arterial saturation, pH, and calculated Q_p:Q_s decreased significantly with banding (P = .026, .002, and .004, respectively). Clinical effects varied among patients, with hemodynamically stable patients achieving the most benefit. Adjustment of the band was required in 1 patient. No shunt thrombosis or shunt banding-related complications were noted.

CONCLUSIONS

Our formulas and surgical strategy offer a new approach to controlling excessive pulmonary blood flow in shunt-dependent circulations in an effective and predictable way. The best reproducibility was achieved in small, thin-walled shunts. This strategy was most effective in patients with pulmonary overcirculation without hemodynamic decompensation.

Anomalous Aortic Origin of a Coronary Artery

Background:

Anomalous aortic origin of a coronary artery (AAOCA) is a common congenital heart lesion that may be rarely associated with myocardial ischemia and sudden death in the young. Evidence-based criteria for managing young patients with AAOCA are lacking. The Congenital Heart Surgeons Society (CHSS) established a multicenter registry of patients with AAOCA aged ≤30 years to develop these criteria.

Methods:

All institutional members of the CHSS are eligible to enroll patients. Patients were enrolled retrospectively if diagnosis of AAOCA occurred between January 1, 1998, and January 20, 2009, and prospectively from January 20, 2009 forward. The first phase of analysis explored possible associations between demographics, symptoms, coronary anatomy, and management using correlation analysis and logistic regression.

Results:

As of June 2012, 198 patients were enrolled from CHSS member institutions (median age at diagnosis = 10.2 years; 64% male). Data were extracted from clinical records. Fifty-four percent were symptomatic at presentation (most commonly chest pain, N = 78). The AAOCA was diagnosed at autopsy in two patients who presented with sudden death (one with anomalous aortic origin of the left coronary artery [AAOLCA]; one with a single ostium above a commissure giving rise to both left and right coronary arteries). Imaging reports documented anomalous aortic origin of the right coronary artery (AAORCA) in 144 patients, AAOLCA in 51 patients, and AAOLCA/AAORCA in 1 patient. Surgery or autopsy without surgery was performed in 106 patients (71 AAORCA [67%]; 31 AAOLCA [29%]; and 4 AAORCA/AAOLCA [4%]) at a median age of 12.6 years. Overall, 52% of patients with AAORCA versus 67% with AAOLCA had surgery. Most surgical operative reports described an intramural segment of the coronary artery with anomalous origin. Surgery correlated with symptoms, older age, and presence of an intramural segment in the setting of AAOLCA.

Conclusions:

Management decisions, including surgical referral, are associated with patient symptoms and coronary morphology. Information derived from annual follow-up of surgically and nonsurgically managed patients enrolled in the registry will eventually form the basis for development of evidence-based protocols to address the spectrum of risk and inform clinical decision making in this heterogeneous population of young patients.

Unbalanced atrioventricular septal defect: definition and decision making

Unbalanced atrioventricular septal defect is an uncommon lesion with widely varying anatomic manifestations. When unbalance is severe, diagnosis and treatment is straightforward, directed toward single-ventricle palliation. Milder forms, however, pose a challenge to current diagnostic and therapeutic approaches. The transition from anatomies that are capable of sustaining biventricular physiology to those that cannot is obscure, resulting in uneven application of surgical strategy and excess mortality. Imprecise assessments of ventricular competence have dominated clinical decision making in this regard. Malalignment of the atrioventricular junction and its attendant derangement of inflow physiology is a critical factor in determining the feasibility of biventricular repair in the setting of unbalanced atrioventricular septal defect. The atrioventricular valve index accurately identifies unbalanced atrioventricular septal defect and also brings into focus a zone of transition from anatomies that can support a biventricular end state and those that cannot.

Echocardiographic features defining right dominant unbalanced atrioventricular septal defect: a multi-institutional Congenital Heart Surgeons' Society study

BACKGROUND

Definition and management of right dominant unbalanced atrioventricular septal defect (AVSD) remains challenging because unbalance entails a spectrum of left heart hypoplasia. Previous work has highlighted atrioventricular valve (AVV) index as a reasonable defining echocardiographic measure. We sought to assess which additional echocardiographic features might provide further characterization.

METHODS AND RESULTS

From a multi-institutional cohort of complete AVSD, 52 preoperative echocardiograms of patients with presumed right dominant unbalanced AVSD (based on AVV index) and 60 randomly selected preoperative echocardiograms from patients with presumed balanced AVSD were reviewed. Cluster analysis of echocardiographic variables was used to group patients with similar features. Discriminant function analysis was used to explore which variables differentiated these groups. Three groups were identified from the cluster analysis. Echocardiographic variables that differentiated these groups were right ventricle:left ventricle inflow angle, LV width/LV length, left AVV color diameter at smallest inflow, left AVV color diameter at annulus, right AVV overriding left atrium, and LV width. Based on procedures and outcomes, 1 group likely represented balanced patients, whereas 2 groups with similar outcomes likely represented unbalanced patients. The dominant differentiating echocardiographic variable between the 3 cluster groups was the right ventricle:LV inflow angle (partial R²=0.86), defined as the angle between the base of the right ventricle and LV free wall, using the crest of the ventricular septum as apex of the angle.

CONCLUSIONS

The angle of right ventricle/LV inflow and other surrogates of inflow may be important defining echocardiographic measures of right dominant unbalanced AVSD, although confirmation is needed.

Costs of prenatal detection of congenital heart disease

Little information is available about the transportation costs incurred from the missed prenatal diagnosis of congenital heart disease (CHD). The objectives of the present study were to analyze the costs of emergency transportation related to the postnatal diagnosis of major CHD and to perform a cost/benefit analysis of additional training for ultrasound technicians to study the implications of improved prenatal detection rates. The 1-year costs incurred for emergency transportation of pre- and postnatally diagnosed infants with CHD in Northern California and North Western Nevada were calculated and compared. The prenatal detection rate in our cohort (n = 147) was 30.6%. Infants postnatally diagnosed were 16.5 times more likely (p <0.001) to require emergency transport. The associated emergency transportation costs were US$542,143 in total for all patients with CHD. The mean cost per patient was $389.00 versus $5,143.51 for prenatally and postnatally diagnosed infants, respectively (p <0.001). Assuming an improvement in detection rates after 1-day training for ultrasound technicians, the investment in training cost can be recouped in 1 year if the detection rate increased by 2.4% to 33%. Savings of $6,543,476 would occur within 5 years if the detection rate increased to 50%. In conclusion, CHD diagnosed postnatally results in greater costs related to emergency transportation of ill infants. Improving the prenatal detection rates through improved ultrasound technician training could result in considerable cost savings.

Echocardiographic definition and surgical decision-making in unbalanced atrioventricular septal defect: a Congenital Heart Surgeons' Society multiinstitutional study

BACKGROUND

Although identification of unbalanced atrioventricular septal defect (AVSD) is obvious when extreme, exact criteria to define the limits of unbalanced are not available. We sought to validate an atrioventricular valve index (AVVI) (left atrioventricular valve area/total atrioventricular valve area, centimeters squared) as a discriminator of balanced and unbalanced forms of complete AVSD and to characterize the association of AVVI with surgical strategies and outcomes.

METHODS AND RESULTS

Diagnostic echocardiograms and hospital records of 356 infants with complete AVSD at 4 Congenital Heart Surgeons' Society (CHSS) institutions (2000-2006) were reviewed and AVVI measured (n=315). Patients were classified as unbalanced if AVVI≤0.4 (right dominant) or ≥0.6 (left dominant). Surgical strategy and outcomes were examined across the range of AVVI. Competing risks analysis until the time of commitment to a surgical strategy examined 4 end states: biventricular repair (BVR), univentricular repair (UVR), pulmonary artery banding (PAB), and death before surgery. A prediction nomogram for surgical strategy based on AVVI was developed. The majority of patients had balanced AVSD (0.4<AVVI<0.6) and underwent BVR. Patients with AVVI<0.19 uniformly underwent UVR. Heterogeneous repair strategies were found when 0.19≤AVVI≤0.39 (UVR and BVR), with a disproportionate number of deaths in this range. AVVI≥0.6 (left dominant) was less common. The proportion of subjects predicted for the end states at 12 months after diagnosis are: BVR, 86%; UVR, 7%; PAB, 1%; death without surgery, 1%; alive without surgery, 5%.

CONCLUSIONS

AVVI effectively characterizes the transition between balanced and unbalanced AVSD with important correlation to anatomic substrate and selected surgical strategy.

Inflammation and infection in nine surgically explanted Medtronic Freestyle® stentless aortic valves

BACKGROUND

The Medtronic Freestyle valve is fixed in glutaraldehyde at zero pressure on the cusps and treated with alpha-amino oleic acid. This valve reportedly has excellent clinical and hemodynamic results, but little has been reported about its long-term pathology.

METHODS AND RESULTS

Nine Freestyle valves explanted between 2003 and 2005 were reviewed to assess the reasons for bioprosthesis failure (six implanted at our institution). All valves were examined in detail, using histochemistry and immunohistochemistry to identify the cellular response. One Freestyle valve, explanted for mitral valve endocarditis on the fifth postoperative day, was excluded from analysis. Average implant duration was 52.8+/-35.5 months. Four valves were explanted for infective endocarditis, three for aortic insufficiency, two for aortic stenosis with cusp calcification seen in five valves, pannus and thrombus in all valves and a chronic inflammatory reaction involving the xenograft arterial wall seen in eight of nine valves. This was associated with significant damage to the porcine aortic wall in seven cases, and cusp myocardial shelf damage in six cases.

CONCLUSIONS

In this series of valves, we found (1) infective endocarditis; (2) pannus, thrombus, and calcification; and (3) unusual and significant inflammatory reaction and aortic tissue damage, which could by itself lead to aortic incompetence.

Quantitative analysis of catheter roughness induced by cutting and manipulation: a potential prothrombotic risk

Thrombosis is a major complication of central venous access devices, its incidence depending on material, diameter, tip position, and tip surface. Catheters are usually cut to the appropriate length for accurate positioning. Cutting is not recommended, however, as rough surfaces can serve as a nidus for thrombosis. The present study was performed to assess the roughness of catheter tips provided by various manufacturers versus the roughness once cut and handled. Three types of catheters (Hickman, Port-a-Cath, and Per Q Cath) were cut by scissors, iris scissors, or scalpel, and were handled with debakey forceps, a needle driver, adson with teeth or adson without teeth, to determine the damage created on the catheter. The uncut manufactured tip was compared as a control. Scanning electron microscopy was used for imaging of all samples, and roughness was quantified by atomic force microscopy for the cutting methods. Qualitative results by scanning electron microscopy showed that scalpel-cut and manufactured ends appeared smoother relative to those cut with scissors or iris scissors. This complemented the roughness analysis by atomic force microscopy. Catheters handled by debakey forceps and adsons with teeth showed most roughness, visible as deep holes or a grainy surface when observed by high-magnification scanning electron microscopy. Overall, the smoothest result was produced by scalpel, followed by the manufactured end, scissors, and iris scissors. Handling should be minimized, and use of adsons with teeth, needle drivers and debakey forceps should be avoided, as they can leave permanent damage. Adsons without teeth appeared the least damaging.

Pathologic Analysis of 19 Heart Valves With Silver-Coated Sewing Rings

OBJECTIVE

The St. Jude Medical Silzone (Silzone) mechanical heart valve was voluntarily recalled (January 2000) due to an unusually high incidence of paravalvular leaks. We present the first series of human morphological data on the failure of these valves.

METHODS

Nineteen Silzone valves were evaluated from the 176 Silzone valves implanted in 147 patients at our institution between 1997 and 1999. Explanted prostheses were fixed in 10% formalin, photographed, and X-rayed. Histological sections were collected from the sewing cuff, accompanying tissues, and thrombus. For comparison, six age-matched SJM-standard valves were similarly analyzed.

RESULTS

Nineteen Silzone valves from 16 patients (10 male, six female, 52.0 +/- 15.2 years) were examined. Significantly more mitral (15/95) prostheses were removed than aortic (4/81) despite the nearly equal number implanted (p = 0.027). Fifteen of the Silzone valves (13/16 patients) were explanted in the early postoperative period (within six months of implantation), although collection continued for eight years after our institution stopped implanting them. The common indications for surgical explantation were paravalvular leak (8/12) and clinically suspected infective endocarditis (IE) (four patients, five valves). IE was not confirmed by histology or culture in any valve. The sewing cuffs of many Silzone valves showed large regions of pannus, granulation tissue, and purulent exudate. Polymorphonuclear leukocytes were more common in the sewing cuff of Silzone valves; however, the cellular infiltrate was superficial when compared to SJM-standard valves.

CONCLUSION

This is the largest morphologically analyzed series of Silzone explants. It demonstrates a consistent pattern of atypical tissue incorporation into the silver-coated sewing ring particularly in the mitral position. Clinical and morphologic features of IE (sterile) are seen in the early postimplant period. Prosthesis-related problems were almost wholly seen at the mitral site, in our group. Our current data indicate that although early failure due to dehiscence and paravalvular leak is a problem, Silzone valves that "survive" past six months will likely function as well as the SJM-standard prosthesis.

Pathology of infectious and inflammatory diseases in prosthetic heart valves

Prosthetic heart valves, both mechanical and biological (xenograft valves, stented or unstented), show an inflammatory reaction (infective endocarditis), associated predominantly with bacterial/fungal infection. Somewhat surprisingly, no immune-mediated reaction has been reported thus far. This may, among other reasons, be related to the fact that the tissues are "fixed" with aldehydes and are virtually isolated from host circulation, separated by synthetic material (the valve stent and the fabric covering it). Stentless valves (especially these without fabric covering them), however, have no such "isolation" from the host circulation. While the Toronto-Stentless Porcine Valve has a covering of fabric, the Medtronic Freestyle valve has no such covering. It is perhaps not so surprising therefore that at the intermediate time point of 5 to 6 years, some valves are beginning to show such an immune reaction.