The impact of surgical repair on left ventricular outflow tract in atrioventricular septal defect with common atrioventricular valve orifice.

Objective: Although a narrow left ventricular outflow tract in atrioventricular septal defect is related to its intrinsic morphology, the contribution from the repair technique remains to be quantified. Methods: A total of 108 patients with an atrioventricular septal defect with a common atrioventricular valve orifice were divided into 2 groups: 2-patch (N = 67) and modified 1-patch (N = 41) repair. The left ventricular outflow tract morphometric was analyzed by quantifying the degree of disproportion between subaortic and aortic annular dimensions (disproportionate morphometrics ratio was defined as ≤ 0.9). Z-scores (median, interquartile range) were further analyzed in a subset of 80 patients with immediate preoperative and postoperative echocardiography. A total of 44 subjects with ventricular septal defects served as controls. Results: Before repair, 13 patients (12%) with an atrioventricular septal defect had disproportionate morphometrics (vs 6 [14%] ventricular septal defect P = .79), but the subaortic Z-score (-0.53, -1.07 to 0.06) was lower than the ventricular septal defect (0.07, -0.57 to 1.17; P < .001). After repair, both 2-patch (8 [12%] preoperatively vs 25 [37%] postoperatively; P = .001) and modified 1-patch (5 [12%] vs 21 [51%], P < .001) procedures showed a greater degree of disproportionate morphometrics. Both 2-patch (postoperatively -0.73, -1.56 to 0.08 vs preoperatively -0.43, -0.98 to 0.28; P = .011) and modified 1-patch (-1.42, -2.63 to -0.78 vs -0.70, -1.18 to -0.25; P = .001) procedures also demonstrated lower subaortic Z-scores postrepair. The postrepair subaortic Z-scores were lower in the modified 1-patch group (-1.42 [-2.63 to -0.78]) compared with the 2-patch group (-0.73 [-1.56 to 0.08]; P = .004). Low postrepair subaortic Z-scores (<-2) were observed in 12 patients (41%) in the modified 1-patch group and 6 patients (12%) in the 2-patch group (P = .004). Conclusions: Surgical correction resulted in greater disproportionate morphometrics seen immediately postrepair. The impact on the left ventricular outflow tract was observed in all repair techniques, with a greater burden seen after modified 1-patch repair. Video Abstract: This morphometric study in AVSD with common atrio-ventricular valve orifice confirmed further derangements of LV outflow tract morphometrics immediately after surgical repair.

The role of abnormal subaortic morphometry as a substrate for left ventricular outflow tract obstruction following atrioventricular septal defect repair.

OBJECTIVES: Although left ventricular outflow tract (LVOT) obstruction is a recognized risk after atrioventricular (AV) septal defect (AVSD) repair, quantitative assessments to define the substrate of the obstruction are lacking. METHODS: Morphometric analyses were based on measurements from early 2-dimensional echocardiographic scans (within 3 months postoperatively) for 117 patients (82 CAVVO = common AV valve; 35 SAVVO = separate AV valve orifices), which were compared to 50 age/weight matched controls (atrial septal defect/ventricular septal defect). Late echocardiographic analyses were performed in 57 patients with AVSD (follow-up range, 1.2-10.7 years). RESULTS: Adequate z scores (above -2.5) were observed in 109 (93%) patients with AVSD at the aortic annulus and in 89 (76%) with AVSD in the subaortic area. Compared to the control group, patients with AVSD had lower median z scores at the aortic annulus (-0.64 vs 0.60; P < 0.001) and the subaortic areas (-1.48 vs 0.59; P < 0.001), disproportionate subaortic/aortic annulus ratio <1.00 (67% vs 22%; P < 0.001), narrower annuloaortic-septal angle (94.0 vs 104.0; P < 0.001) and annuloaortic left AV valve angle (78.0 vs 90.0; P < 0.001). Compared to patients with CAVVO, those with SAVVO had narrower annuloaortic-septal angles (P = 0.022) that persisted at late analysis, with lower subaortic/aortic annular ratios (P = 0.039). In patients with CAVVO, lower early postoperative subaortic z scores were found following modified single-patch repairs (median -2.12 vs -1.02 in two-patch repairs; P = 0.004). A total of 6/117 (5%) patients (4 CAVVO, 5% and 2 SAVVO, 6%) required reoperations for LVOT obstruction (mean 6.9 years postoperatively), with no difference in morphology or types of operations. CONCLUSIONS: Despite having adequate z scores, patients with AVSD demonstrated abnormal LVOT morphometrics early postoperatively. Besides intrinsic morphology, repair techniques may have an impact on postoperative LVOT morphometrics and requires further evaluation.

Superior Vena Cava Inflow Following Repair for Anomalous Right Pulmonary Venous Drainage in Children.

Risk of superior vena cava (SVC) obstruction following repair of anomalous right upper pulmonary veins in children is unclear. The incidence and outcome of subclinical obstruction remained unknown. Retrospective single institutional study (07/1993-02/2017) in a pediatric population (N = 42, median age 3.9-year, range 0.1-15.3 years). 33 (79%) children had repair without SVC translocation ("non-Warden") and 9 (21%) had Warden-type surgery. Echocardiographic SVC obstruction was defined as (I) turbulent flow across SVC and (II) continuous flow pattern without return to baseline velocity (0 m/s); severe obstruction was defined as loss of distinct biphasic profile ± mean gradient ≥ 5 mmHg. 3 (7%) patients required intra-operative revision due to obstruction (non-Warden: 1, Warden: 2). After discharge, 2 (5%) patients required reintervention (3 and 6-month post-op) for severe symptomatic obstruction (non-Warden: 1, Warden-type: 1). Both patients responded to balloon angioplasty with symptomatic resolution (one required repeat catheter reintervention). 10 (24%) patients had subclinical echocardiographic obstruction (2, 22% Warden vs. 8, 24% non-Warden; p = 1.0; 8 of 10 patients had mild gradient), which resolved and remained well without reintervention. At follow-up (mean 7.2-year, range 0-23 years), all patients were alive. Freedom from SVC reintervention at 10 and 20-year is 95% (97% at 10, 20-year in non-Warden and 89% at 5, 8-year in Warden-type group; log-rank p = 0.34). Surgical repair for anomalous right upper pulmonary veins is associated with risk of SVC obstruction in children. The need for reintervention for severe obstruction is rare at late follow-up. Patients with subclinical obstruction remain asymptomatic and demonstrate echocardiographic improvement.

Synergistic interaction between right ventricular mechanical dyssynchrony and pulmonary regurgitation determines early outcome following tetralogy of Fallot repair.

OBJECTIVE: The ability of the right ventricle to tolerate acute pulmonary regurgitation (PR) following tetralogy of Fallot (TOF) repair is variable and the mechanisms that underlie this are not completely understood. We hypothesise that dyssynchronous wall mechanics affects the RV tolerance to postoperative PR with adverse effect on early surgical outcome. METHODS: Twenty-four TOFs (mean age 19.5+/-15.5 months) undergoing elective repair were prospectively recruited. Ventricular wall mechanics was studied by tissue Doppler echocardiography following induction (preop) and postoperative day one (POD1) and compared with a control group (10 VSD/AVSD). Segmental dyssynchrony, defined as out-of-phase peak myocardial contraction, was determined at the base, mid, apical segments of the septum, RV and LV free walls and scored by the total number of affected segments. PR was graded from absent to severe and RV dimension was quantified by end-diastolic area index (RVEDAI). Cardiac index (CI) was measured by pulse contour cardiac output analysis. Outcome measures were CI, mixed venous oxygen saturation (SvO2), lactate, and duration of ventilation and critical care stay. RESULTS: Preoperatively, biventricular free-wall motion was synchronous in both groups. Following surgery, TOF developed RV-septal dyssynchrony (>2 segments in 11 (46%) vs none in control, p=0.01), while the LV free wall remained normal in both groups. RV-septal dyssynchrony correlated with the ventilation time (rho=0.69, p=0.003), critical care stay (rho=0.58, p=0.02) in the presence of PR (n=16), but not with other outcome measures. The relationships between dyssynchrony and early outcome were not seen when PR was absent. In the presence of PR, median RVEDAI was greater with higher dyssynchrony score (>3 segments; p=0.009). The degree of PR did not affect critical care/ventilation time or RVEDAI. The presence of transannular patch (p=0.007) or at least moderate PR (p=0.01) was associated with a more severe dyssynchrony. CONCLUSIONS: Dyssynchronous RV-septal wall mechanics occurs early after Fallot repair. The magnitude of dyssynchrony appears to interact synergistically with pulmonary regurgitation to influence RV dimension and early outcome.

Tissue Doppler imaging following paediatric cardiac surgery: early patterns of change and relationship to outcome.

In this study, tissue Doppler imaging (TDI) was used to assess changes in ventricular function following repair of congenital heart defects. The relationship between TDI indices, myocardial injury and clinical outcome was explored. Forty-five children were studied; 35 with cardiac lesions and 10 controls. TDI was performed preoperatively, on admission to paediatric intensive care unit (PICU) and day 1. Regional myocardial Doppler signals were acquired from the right ventricle (RV), left ventricle (LV) and septum. TDI indices included: peak systolic velocities, isovolumetric velocities (IVV) and isovolumetric acceleration (IVA). Preoperatively, bi-ventricular TDI velocities in the study group were reduced compared with normal controls. Postoperatively, RV velocities were significantly reduced and this persisted to day-1 (PreOp vs. PICU and day-1: 7.7+/-2.2 vs. 3.4+/-1.0, P<0.0001 and 3.55+/-1.29, P<0.0001). LV velocities initially declined but recovered towards baseline by day-1 (PreOp vs. PICU: 5.31+/-1.50 vs. 3.51+/-1.23, P<0.0001). Isovolumetric parameters in all regions were reduced throughout the postoperative period. Troponin-I release correlated with longer X-clamp times (r=0.82, P<0.0001) and reduced RV velocities (r=0.42, P=0.028). Reduced pre- and postoperative LV velocities correlated with longer ventilation (PreOp: r=0.54, P=0.002; PostOp: r=0.42, P=0.026). This study identified reduced postoperative RV velocities correlated with myocardial injury while reduced LV TDI correlated with longer postoperative ventilation.

Feasibility and safety of immediate perioperative implantation of intravascular stents in cavopulmonary pathways.

Fontan-type procedures are widely used for palliation of patients with many forms of a functional univentricular heart. An ideal Fontan circuit should be free of any distortion or stenosis. The use of stents for the treatment of stenotic and hypoplastic vessels is well established in pediatric cardiac practice. We report the successful use of endovascular stents during the immediate postoperative period in patients undergoing cavopulmonary anastomoses.