Evidence for palliative enlargement of the right ventricular outflow tract in severe tetralogy of Fallot.

OBJECTIVE

If the pulmonary artery (PA) tree in patients with Fallot's tetralogy (TOF) is extremely hypoplastic, a shunt procedure may be difficult and not desirable because of side-effects. Moreover, the failing catch-up growth of the pulmonary annulus is well known. In patients with a severe form of TOF, we performed palliative transannular patching of the right ventricular outflow tract. The early and long-term follow-up was evaluated.

METHODS

Eleven patients (93 days (10-245 days); 3.5+/-0.7 kg (2.5-4.3 kg)) had highly symptomatic TOF (Hb: 18+/-2g/dl, SO2: 68+/-11%); angiographic diameters: RPA: 4.1 mm (2.5-6.4 mm), LPA: 3.4 mm (1.6-7.0 mm), PA trunc: 4.4 mm (2.5-7.0 mm). All 11 underwent transannular enlargement of the right ventricular outflow tract without closure of the ventricular septum defect. A PA index (cross-sectional area of the pulmonary arteries to BSA) was used to compare pre- and postoperative data. For follow-up, the patients were repetitively examined clinically and echocardiographically.

RESULTS

Preoperative PA index was 87+/-40 mm2/m2 (normal: 330+/-35 mm2/m2). Postpalliation angiograms (age: 10-14 months) demonstrated a significant catch-up growth in nine patients (PA index from 99+/-40 to 310+/-54 mm2/m2) and inadequate growth in two patients (PA index 63 and 115 mm2/m2). Perioperative mortality was zero. Ten patients (43 months; 6-105 months) underwent elective repair. Six patients received pulmonary homograft valves (6-15 years after repair) because of severe pulmonary valve insufficiency and severe RV dilation.

COMPLICATIONS: One patient died 10 months postpalliation due to pneumonia, one patient received a pacemaker after repair and died (2 months post-repair) due to pacemaker failure, a 5-year-old patient died 1 month after repair due to sepsis. All eight long-term survivors (12-17 years) are in excellent clinical condition. Echocardiography revealed good RV function and near normal diameters at peak systolic pressures between 25 and 50 mmHg. Only one patient developed brady-arrhythmia; a pacemaker was implanted 8 years after repair and 2 years after homograft implantation.

CONCLUSIONS

In a very severe form of TOF, palliative right ventricular outflow tract construction may provide the potential for complete repair. In the presented high-risk patient group, mortality was not related to the hypoplastic pulmonary arteries. Obviously, all patients need pulmonary valve implantation in the long run.