Significant intraoperative right ventricular outflow gradients after repair for tetralogy of Fallot: to revise or not to revise?

BACKGROUND: This study was performed to define alternative parameters for the management of intraoperative residual right ventricular outflow obstruction (RVOTO) after transatrial repair of tetralogy of Fallot (ToF) in order to differentiate those requiring immediate revision from those who do not. METHODS: Since October 1995, 166 patients of ToF underwent transatrial repair. Postbypass residual RVOTO was assessed by surgeon's subjective impression, direct intracardiac pressure measurements, and intraoperative echocardiography (IOE). RVOTO was labeled "significant" whenever it exceeded a gradient of 40 mm Hg on IOE or right ventricular to left ventricular pressure ratio (pRV/LV) exceeded 0.85. Further, on IOE, significant RVOTO was defined "fixed", if there was no change in RVOT dimensions during the cardiac cycle, along with the presence of anatomic substrate for obstruction, and "dynamic" if RVOT dimensions increased appreciably in diastole. Postoperative course and follow-up echocardiograms of all patients were analyzed. RESULTS: Significant RVOTO was detected in 58 (35%) patients (mean gradient 54 mm Hg). Seven (12%) of them with fixed obstruction (mean 46 mm Hg) underwent immediate surgical revision, while the remaining 51 patients with mean gradient of 78 mm Hg (including 10 patients with pRV/LV ratio of > or = 1.0) with dynamic obstruction did not undergo revision. There were six (3.6%) early deaths. Operative mortality and postoperative morbidity were not related to higher residual gradients, although the first 15 such patients had longer intensive care stay and inotropic support, in which this was done electively. On follow-up (mean 18.5 months), outflow gradients declined sharply (mean 16 mm Hg) irrespective of the severity of intraoperative gradients (p < 0.001). There were no reoperations or late deaths. CONCLUSIONS: This study shows that: 1) existing parameters for immediate revision of residual RVOTO possibly need to be reviewed; 2) intraoperative echocardiography helps in differentiating "fixed" from "dynamic" obstruction and helps obviate needless revisions; and 3) dynamic RVOT gradients decline significantly irrespective of their severity after transatrial repair of ToF.

Intraoperative echocardiography as a routine adjunct in assessing repair of congenital heart defects: experience with 300 cases.

Utility of intraoperative echocardiography (IOE) in perioperative management of congenital heart disease has been reported in literature. However, its consistent use as a monitoring tool has not yet been reported from our country. The aim of this study was to evaluate the role of routine use of IOE for intraoperative assessment of surgical repairs in terms of residual shunt, residual gradient, valvular insufficiency and ventricular function. Three hundred consecutive patients above 3 Kg body weight were included in this study. In 152 patients epicardial and in 148 patients transoesophageal echocardiography (TEE) was performed intraoperatively. Age ranged from 4 months to 52 years (median 5.8 yrs) and body weight from 3 Kg to 62 Kg (Median 12 Kg). IOE Doppler and Doppler colour flow imaging studies were performed before cardiopulmonary bypass (CPB) whenever feasible and after CPB in all patients. Pre-bypass examination yielded additional information in 17 (5.6%) patients. In 9 (3%) such patients it had an impact on surgery. In post CPB IOE studies, surgery was found to be 'perfect' in 210 (70%) patients and 'acceptable' residual defects in 70 (23.3%) patients. In 20 (6.6%) cases post CPB IOE found surgical repair 'unacceptable'. Ten of these patients required immediate surgical revision with excellent outcome, thus saving them from late reoperation or postoperative complications. No short term complications were encountered relating to the procedure. We conclude that intraoperative echocardiography is an inexpensive, accurate, valuable and safe addition to the perioperative care of patients and should be mandatory during all corrective surgical procedures for congenital heart disease. It is especially applicable in our country where the costs of reoperation for residual defects are prohibitive.