Fetal left and right ventricular strain parameters using speckle tracking in congenital heart diseases

Assessment of fetal ventricular function is mostly subjective, and currently, for the objective assessment left ventricular shortening fraction is obtained. However, this by itself is not very reliable. Hence, more tools that can provide an objective assessment are needed to increase the confidence of functional assessment. Speckle tracking imaging can provide one such tool. In this study we sought to establish the normative value of global longitudinal and circumferential strain for our fetal patients and for two major forms of congenital heart diseases, namely atrioventricular canal defects (AVC) and uncorrected dextro-transposition of the great arteries (dTGA) to act as a benchmark. The study was completed via a single center retrospective analysis on 72 fetal echocardiograms (26 normal, 15 dTGA, and 31 AVC). Tomtec Arena™ echocardiography analysis software was used for analysis. In normal fetuses, mean left ventricular (LV) global longitudinal strain (GLS) was - 22.6% (95% CI -24, -21.1) and mean right ventricular (RV) GLS was - 22.1% (95% CI -23.6, -20.6). In AVC patients LV GLS was-26.6% (95% CI -28,-25.3) and mean RV GLS was - 26.5% (95% CI -27.9,-25.2). In dTGA patients LV GLS was - 22.9% (95% CI of -24.8, -21) and RV GLS was - 21.3% (95% CI was - 23.4, -20.8). There was good intra-rater reliability though poor to fair inter-rater reliability. Notwithstanding its current limitations, strain imaging can provide useful information that can increase confidence of cardiac functional assessment in fetal patients. However, to be reliable across the board, further automation and standardization is required.

Double orifice and atrioventricular septal defect: dealing with the zone of apposition†

OBJECTIVES

A double orifice of the left atrioventricular valve (LAVV) associated with atrioventricular septal defects (AVSD) can significantly complicate surgical repair. This study reports our experience of AVSD repair over 3 decades, with special attention to the zone of apposition (ZoA) of the main orifice, and presents a technique of hemivalve pericardial extension in specific situations.

METHODS

We performed a retrospective study from 1987 to 2016 on 1067 patients with AVSD of whom 43 (4%) had a double orifice, plus 2 additional patients who required LAVV pericardial enlargement. Median age at repair was 1.3 years. Mean follow-up was 8.2 years (1 month-32 years).

RESULTS

Associated abnormalities of the LAVV subvalvular apparatus were found in 7 patients (5 parachute LAVV and 2 absence of LAVV subvalvular apparatus). ZoA was noted in 4 patients (9%): partially closed in 15 (35%) and completely closed in 24 (56%). Four patients required, either at first repair or secondarily, a hemivalve enlargement using a pericardial patch without closure of the ZoA. The early mortality rate was 7% (n = 3), all before 2000. Two patients had unbalanced ventricles and the third had a single papillary muscle. There were no late deaths. Six patients (14%) required 7 reoperations (3 early and 4 late reoperations) for LAVV regurgitation and/or dysfunction, of whom 4 (9%) required mechanical LAVV replacement (all before 2000). Freedom from late LAVV reoperation was 97% at 1 year, 94% at 5 years and 87% at 10, 20 and 30 years. Unbalanced ventricles (P = 0.045), subvalvular abnormalities (P = 0.0037) and grade >2 LAVV postoperative regurgitation (P = 0.017) were identified as risk factors for LAVV reoperations. Freedom from LAVV mechanical valve replacement was 95% at 1 year, 90% at 5 years and 85% at 10, 20 and 30 years. An anomalous LAVV subvalvular apparatus was identified as a risk factor for mechanical valve replacement (P = 0.010). None of the patients who underwent LAVV pericardial extension had significant LAVV regurgitation at the last follow-up examination.

CONCLUSIONS

Repair of AVSD and double orifice can be tricky. Preoperative LAVV regurgitation was not identified as an independent predictor of surgical outcome. LAVV hemivalve extension appears to be a useful and effective alternate surgical strategy when the ZoA cannot be closed.