One and a half ventricle repair in adults: postoperative hemodynamic assessment using phase-contrast magnetic resonance imaging.

BACKGROUND

One and a half ventricle repair (1½ repair) strategy has been used for patients with a hypoplastic or dysfunctional right ventricle (RV), or both. We sought to assess the postoperative hemodynamics of 1½ repair using phase-contrast magnetic resonance imaging (PC-MRI).

METHODS

Ten adults, 9 with Ebstein's anomaly and 1 with tricuspid stenosis, underwent 1½ repair (median age at operation, 42.4 years). The azygos vein was left open in all patients on 1½ repair to prevent severe postoperative central venous hypertension. Postoperative PC-MRI studies were performed to measure blood flow to the ascending aorta (QAsc-Ao), the main pulmonary artery (QMPA), the superior vena cava (SVC) (QSVC), and the branch pulmonary arteries and veins. From these values, blood flow to the upper compartment of the body (QUC), right ventricular volume unloading effect (QMPA/QAsc-Ao), proportion of blood flow to the upper compartment of the body (QUC/QAsc-Ao), and venous return to arterial forward flow ratio of the upper compartment of the body (QSVC/QUC) were calculated. Two patients also underwent preoperative PC-MRI.

RESULTS

On PC-MRI, QMPA/QAsc-Ao, QUC/QAsc-Ao, and QSVC/QUC were 0.58 to 0.84 (median, 0.67), 0.19 to 0.36 (median, 0.27), and 0.47 to 1.57 (median, 0.93, lower than 1.0 in 7 patients), respectively. In 2 patients who had preoperative and postoperative PC-MRI, QUC/QAsc-Ao decreased from 0.26, 0.32 to 0.21, 0.28, respectively.

CONCLUSIONS

After 1½ repair, right ventricular volume unloading was effective in all patients, but intercaval collateral veins (ie. QSVC/QUC<1) appeared to develop in most of the patients. Furthermore blood flow to the upper compartment of the body appeared to diminish, presumably due to postoperative elevation of central venous pressure.