Michael Gritti

Aortic valve repair for insufficiency in older children offers unpredictable durability that may not be advantageous over a primary Ross operation

OBJECTIVES To evaluate the durability of aortic valve (AoV) repair relative to other strategies for children with significant aortic insufficiency (AI). METHODS From 2001 to 2012, 90 children with greater than or equal to moderate AI underwent surgery. Resulting procedures were classified according to final operative outcome: AoV repair (repair; n = 46, 51%), Ross procedure (Ross; n = 21, 23%) or replacement with mechanical or tissue prosthesis [aortic valve replacement (AVR); n = 23, 26%]. Repeated measures (n = 1081 echocardiograms) mixed-model analysis and parametric multiphase risk-adjusted hazard analysis were used to evaluate haemodynamic parameters and durability of operations. RESULTS Mean age at operation was similar for repair and Ross groups, but slightly higher for the AVR group (10.6, 11 and 13.2, respectively; P = 0.04). Baseline annular dimensions were similar among groups. Of 46 repairs, 85% involved pericardial leaflet extensions (commonly with leaflet shaving and/or commisuroplasty). The remaining repairs were commissuroplasties. On multivariable analysis, repair was associated with increased early (∼1-2 years) AI and increased outflow tract peak pressure gradients relative to Ross and AVR procedures. On univariate analysis, repairs tended to have a larger annulus size compared with Ross or AVR; however, this was not significant on multivariable analysis. There were 25 reinterventions (surgical reoperation = 16; transcatheter intervention = 9) for 22 children. Freedom from surgical reoperation was 64, 100 and 51% at 6 years for repairs, Ross and AVR, respectively (P = 0.05); however, three of five reoperations after AVR were for failed bioprosthetic devices. The freedom from reintervention was not significantly influenced by the type of AoV operation (P = 0.43). CONCLUSIONS Durability of aortic valve repair for children is limited by recurrence of AI and/or stenosis, often within the first few years. After repair, reoperation should be anticipated within ∼7 years.

Young Infants with Severe Tetralogy of Fallot: Early Primary Surgery versus Transcatheter Palliation

Background: Infants with severe tetralogy of Fallot may undergo (1) early primary surgical repair (EARLY) or (2) early transcatheter palliation (CATH) before delayed surgical repair. We compared these strategies with (3) elective single‐stage tetralogy of Fallot repair (IDEAL). Methods: From 2000 to 2012, 453 children underwent tetralogy of Fallot repair (excluding systemic‐pulmonary shunts), including 383 in the IDEAL (75%), 42 in the EARLY (9%), and 28 in the CATH (6%) groups. IDEAL repair at The Hospital for Sick Children occurs after 3 months. Risk‐adjusted hazard analysis compared freedom from surgical or catheter reintervention. Somatic size, branch pulmonary artery size, and right ventricle systolic pressure were modeled using 2780 echocardiogram reports via mixed‐model regression. Results: CATH involved right ventricular outflow tract stent in 18 patients, right ventricular outflow tract balloon in 9 patients, and ductal‐stent in 1 patient. Three patients died (1 per group). Risk‐adjusted freedom from surgical reoperation was 89% ± 4%, 88% ± 5%, and 85% ± 6% for the IDEAL, EARLY, and CATH groups, respectively, at 10 years. Patients in the EARLY and CATH groups had similar reoperation rates, except for neonates (<1 month), for whom EARLY repair conferred an increased risk of reoperation. Risk‐adjusted freedom from catheter reintervention was lower in the EARLY group (76%) and especially for the CATH group (53%) at 10 years versus the IDEAL group (83%). Somatic growth and progression of right ventricle systolic pressure were similar among groups at 8 years. Although those undergoing EARLY (P = .02) and CATH (P = .09) tend to have smaller branch pulmonary arteries initially, late pulmonary artery size was not significantly different among groups. Conclusions: Early primary repair for neonates may increase surgical reoperation, whereas transcatheter palliation comes at a cost of increased catheter reintervention. However, overall outcomes between groups, in terms of survival, growth, and hemodynamic parameters, were comparable, suggesting that both strategies are a reasonable option for children with severe tetralogy of Fallot.

Aggressive Patch Augmentation May Reduce Growth Potential of Hypoplastic Branch Pulmonary Arteries After Tetralogy of Fallot Repair

BACKGROUND Potential surgical strategies for hypoplastic branch pulmonary arteries (BPAs) during tetralogy of Fallot repair include (1) extensive patch augmentation to the hilum (PATCH), (2) limited extension arterioplasty to the proximal pulmonary artery (EXTENSION), or (3) leaving the native vessels unaugmented (NATIVE). We explored the effect of these strategies on reintervention and BPA growth. METHODS From 2000 to 2012, 434 children underwent complete tetralogy of Fallot repair. Risk-adjusted parametric models were used to analyze the risk of BPA reintervention for (1) all children, (2) children with BPAs of 4 mm or smaller, and (3) children with BPAs of 3 mm or smaller. Repeated-measures analysis of more than 2,000 echocardiograms was used to characterize postoperative BPA growth and right ventricular pressure by using nonlinear mixed models. RESULTS Overall survival (99% [3 deaths]) was excellent. The 10-year freedom from BPA reintervention was 84%. In risk-adjusted models (including baseline BPA z-score), PATCH had a decreased freedom from reintervention (73%; p < 0.01) vs EXTENSION (87%) or NATIVE (91%). For children with BPAs of 4 mm or smaller (28 PATCH, 60 EXTENSION, 75 NATIVE), baseline characteristics were similar. The risk-adjusted 5-year freedom from reintervention was 68% for PATCH, 76% for EXTENSION, and 85% for NATIVE. PATCH trended toward an increased risk of reintervention (p = 0.07). For children with BPAs of 4 mm or smaller left in their NATIVE state, only ∼15% required reintervention. After adjustment for baseline BPA z-score, the time-related BPA growth was decreased (p < 0.014) and right ventricular pressure was increased (p = 0.03) for the PATCH group. CONCLUSIONS Aggressive PATCH augmentation of hypoplastic BPAs improves the short-term geometry but may lead to late stenosis and higher rates of reintervention. Hypoplastic BPAs in tetralogy of Fallot tend (∼85%) to grow well without instrumentation.

“Splint” Mitral Valve Repair for Destructive Endocarditis in Children

Medical management of infective endocarditis in the pediatric population has an associated in-hospital mortality rate of up to 25%. In the past, infective endocarditis of the mitral valve was surgically managed with a valve replacement. Now, there is a shift toward repair. However, for complex lesions in pediatric patients, many institutions are still hesitant to perform a mitral valve repair. We describe the cases of three children with destructive mitral valve endocarditis and risk factors for higher perioperative mortality and morbidity who were successfully treated with a complex mitral valve repair with “splint” patch plasty of the posteromedial commissure.

AVIATION “THREAT AND ERROR MODEL” IN CONGENITAL CARDIOVASCULAR SURGERY: INEFFECTIVE INTRA-OPERATIVE ERROR RESCUE LEADS TO DANGEROUS ERROR CYCLES

tion with response to heparin. METHODS: Pediatric patients had a comprehensive coagulation panel performed prior to cardiac surgery (antithrombin, protein C/S, coagulation factors II (FII), FVII, FVIII, FIX, FX, FXI, FXIII, fibrinogen, prothrombin time/international normalized ratio (PT/INR) and activated partial thromboplastin time). Previously published, age-appropriate values obtained from normal children were used as reference values across age groups. We also examined the effect of preoperative oxygen saturation and C-reactive protein on blood levels of coagulation factors. The Hemostatic Management System (Medtronic) was used to measure response to the initial heparin dose. RESULTS: Of the 157 enrolled patients, 8%were 10 years old; 31% had a cyanotic condition and 11% had recent heparin exposure. Patients had lower coagulation circulating level activity than expected for age, ranging from 61% to 92% of age-appropriate values (p<0.001 for all) with the exception of PT/INR (106% of age-normal, p1⁄40.002) and circulating FVIII (114% of age-normal, p<0.001). Abnormalities were mostly consistent across age groups. Lower oxygen saturation was associated with lower coagulation system activity (FIX:2.6(1.4)% per -10% oxygen saturation, p1⁄40.06; FVII:3.3(1.3)%, p1⁄40.01; protein C:-3.4(1.6)%, p1⁄40.04). Increasing C-reactive protein was associated with increased FX (+4.0(1.8)% per pmol/L C-reactive protein, p1⁄40.03) and fibrinogen levels (+1.5(0.7)g/L per pmol/L C-reactive protein, p1⁄40.03). Response to initial heparin dose (prior to bypass) was impaired in patients with lower activity of the coagulation system, particularly antithrombin, factors II, IX, X, XI and fibrinogen reuslting in greater thrombin generation during cardiac surgery. CONCLUSION: Children about to undergo cardiac surgery have multiple abnormalities within their coagulation system that affect response to heparin; this in turn affects heparin management and monitoring during surgery and predisposes to both thrombosis and bleeding. Future research identifying determinants of heparin sensitivity and developing potential corrective strategies are warranted. CIHR