A PROSPECTIVE, RANDOMIZED TRIAL EVALUATING TRANSATRIAL AND TRANSVENTRICULAR APPROACHES TO REPAIR OF TETRALOGY OF FALLOT

The traditional approach to repair of tetralogy of Fallot involves a r ight ventriculotomy for closure of ventricular septal defect. During t he past two decades, reports of progressive right ventricular dilation and dysfunction, and late occurrence of ventricular arrhythmias, have led investigators to reevaluate this approach and advocate instead th e transatrial-transpulmonary approach, hoping to preserve global right ventricular function. We studied the short term effects on right vent ricular function of either of the two approaches through a prospective randomised study, involving two comparable groups of patients operate d in the same time frame. Between June 1993 and February 1994, 40 pati ents having tetralogy of Fallot with comparable preoperative character istics, were assigned randomly to each of two groups for surgical corr ection. In 20 patients, correction was achieved via the transatrial-tr anspulmonary route. In the other 20 patients, transventricular correct ion was the chosen option. Six months after surgery, patients were eva luated clinically, by Doppler echocardiography, cardiac catheterisatio n, first pass radionuclide angiography and by 24 hours ambulatory elec trocardiographic monitoring, taking note of hemodynamics, abnormalitie s in rhythm, and global right ventricular function. There were no earl y deaths or morbidity in either group. Mean immediate postoperative ra tio between peak right ventricular and systemic pressures was 0.62 +/- 0.22 after transatrial and 0.70 +/- 0.007 after transventricular corr ection. All patients were in functional class I. Six months after surg ery the mean ratio between peak ventricular pressures was similar in t he two groups (transatrial group: 0.37 +/- 0.02, transventricular grou p: 0.38 (0.01), but significantly lower than that measured in the oper ating room. There were no significant arrythmias in either group. Mean right ventricular ejection fraction was nearly the same in both group s (transatrial group versus transventricular group; 44.83 +/- 5.65% ve rsus 42.37 +/- 8.70%). Significant global hypokinesia of the right ven tricle was documented in three patients, and mild hypokinesia in anoth er three, undergoing repair through the transventricular route while i n the group undergoing transatrial repair only one patient had mild hy pokinesia. We conclude that comparable hemodynamic results are obtaine d on short term follow-up after repair of tetralogy of Fallot by eithe r the transatrial or transventricular route. Although more patients in the transventricular group were found to have global hypokinesia of t he right ventricle, longer follow-up is necessary to establish the cli nical relevence of these findings.