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.

A fetal goat model of cardiopulmonary bypass with cardioplegic arrest and hemodynamic assessment.

OBJECTIVE: Increasing evidence shows that some cardiac defects may benefit from fetal interventions, including fetal cardiac surgery. We attempted to develop an in vivo animal model of fetal cardiopulmonary bypass with cardioplegic arrest. METHODS: Operations were performed on 14 pregnant goats. The extracorporeal circulation circuit consisted of a centrifugal pump, silicone tubings with an inner diameter of 6 mm, a roller pump, and a reservoir. The placenta was the sole oxygenator. Cardiopulmonary bypass was maintained at a mean flow rate of 344 ± 68 mL/kg/min, including 30 minutes of cardiac arrest and 15 minutes of reperfusion. Mean arterial blood pressure and heart rate were monitored. Arterial blood samples were analyzed. The pulse index and resistance index of the fetal umbilical artery were monitored. RESULTS: Experiments were completed in 11 cases (79%), with the fetuses weighing 0.65 to 1.8 kg. Fetal mean arterial blood pressure and heart rate remained stable throughout the experiments. A decrease in partial pressure of oxygen with concomitant increase in carbon dioxide partial pressure was noted, but trends were relatively stable. Metabolic acidosis was recognized during and after cardiac bypass. The pulse index and resistance index of the umbilical artery increased significantly after 2 hours off bypass. CONCLUSIONS: We confirmed the technical feasibility of establishing an in vivo model of fetal cardiac bypass with cardioplegic arrest. This fetal goat model provides reproducible data and is suitable to study clinically relevant problems related to fetal cardiopulmonary bypass, myocardial protection, and hemodynamics.