Effect of Preoperative Volume Overload on Left Ventricular Function Recovery After Ventricular Septal Defect Repair

Abstract

Significant left-to-right shunt across a ventricular septal defect (VSD) may lead to left ventricle (LV) volume overload and dilation. The acute loss of LV preload after repair of VSD may contribute to postoperative LV systolic dysfunction. The primary aim of the study is to assess the effect of presence of preoperative LV dilation on LV systolic function recovery after VSD repair. We evaluated the LV systolic function by measuring LV longitudinal strain and ejection fraction (EF) before surgery (time point 1) and at 5 time points after VSD repair (time point 2: 0 to 2 weeks, time point 3: 2 to 6 weeks, time point 4: 6 weeks to 4 months, time point 5: 4 to 12 months, and time point 6: >12 months). A total of 120 patients were included in the study cohort. A total of 84 patients (70%) had LV dilation (group 1) and 36 patients (30%) had normal LV size on preoperative echocardiogram (group 2). Median age (interquartile range 25% to 75%) at surgery was 5.5 months (4 to 10) and 7 months (5 to 44.5) in groups 1 and 2 respectively (p = 0.03). Mean LV EF and strain were not significantly different among the 2 groups at time point 1. At time point 2, both mean EF and strain were significantly lower in group 1 compared with group 2 (p <0.05). At time point 3, mean EF was not significantly different among the two groups, while mean LV strain was significantly lower in group 1 (p = 0.044). At time points 4, 5 and 6, mean EF and strain were not significantly different between the two groups. In conclusion, presence of preoperative LV dilation is associated with a more pronounced LV systolic dysfunction in the early postoperative period only. The LV systolic function recovers back to the baseline after the first year following the repair. These are very reassuring prognostic findings.