Right ventricular dilatation score: a new assessment to right ventricular dilatation in adult patients with repaired tetralogy of Fallot

Background Patients with repaired tetralogy of Fallot (rTOF) experience long-term chronic pulmonary valve regurgitation resulting in right ventricular (RV) dilatation. According to current guidelines, the evaluation of patients with rTOF for RV dilatation should be based on cardiac magnetic resonance (CMR). However, for many asymptomatic patients, routine CMR is not practical. Our study aims to identify screening methods for CMR based on echocardiographic data, with the goal of establishing a more practical and cheap method of screening for severity of RV dilatation in patients with asymptomatic rTOF. Methods Thirty two rTOF patients (mean age, 21(10.5) y, 21 males) with moderate to severe pulmonary regurgitation (PR) were prospectively recruited. Each patient received CMR and echocardiogram examination within 1 month prior to operation and collected clinical data, and then received echocardiogram examination at discharge and 3–6 months post-surgery. Results RV moderate-severe dilatation was defined as right ventricular end-diastolic volume index (RVEDVI) ≥ 160 ml/m2 or right ventricular end-systolic volume index (RVESVI) ≥ 80 ml/m2 in 15 of 32 patients (RVEDVI, 202.15[171.51, 252.56] ml/m2, RVESVI, 111.99 [96.28, 171.74] ml/m2). The other 17 (RVESDI, 130.19 [117.91, 139.35] ml/m2, RVESVI = 67.91 [63.35, 73.11] ml/m2) were defined as right ventricle mild dilatation, i.e., RVEDVI < 160 ml/m2 and RVESVI < 80 ml/m2, and the two parameters were higher than normal values. Compared with the RV mild dilatation group, patients of RV moderate-severe dilatation have worse cardiac function before surgery (right ventricular ejection fraction, 38.92(9.19) % versus 48.31(5.53) %, p < 0.001; Left ventricular ejection fraction, 59.80(10.26) versus 66.41(4.15), p = 0.021). Patients with RV moderate-severe dilatation faced longer operation time and more blood transfusion during operation (operation time, 271.53(08.33) min versus 170.53(72.36) min, p < 0.01; Intraoperative blood transfusion, 200(175) ml versus 100(50) ml, p = 0.001). Postoperative RV moderate-severe dilatation patients have poor short-term prognosis, which was reflected in a longer postoperative hospital stay (6.59 [2.12] days versus 9.80 [5.10] days, p = 0.024) and a higher incidence of hypohepatia (0[0] % versus 4[26.7] %, p = 0.023). Patients with RV dilatation score > 2.35 were diagnosed with RV moderate-severe dilatation (AUC = 0,882; Sensitivity = 94.1%; Specificity = 77.3%). Conclusions RV moderate-severe dilatation is associated with worse preoperative cardiac function and short-term prognosis after PVR in rTOF patients with moderate to severe PR. The RV dilatation score is an effective screening method. When RV dilatation score > 2.35, the patient is indicated for further CMR examination and treatment.