The Norwood procedure - does the type of shunt determine outcome?

Abstract

Background: Stage I palliation of hypoplastic left heart syndrome (HLHS) and its variants is usually performed by a Norwood operation. The management of pulmonary blood flow during this procedure remains controversial. The RV-to-PA conduit (RVPAC) has been proposed as the better alternative compared to a systemic-to-pulmonary shunt (SPS).

Methods: A retrospective single center chart review of consecutive patients who underwent a Norwood I procedure between 01/1997 and 09/2006 was performed. All patients were operated in deep hypothermia, with or without circulatory arrest, using different shunt modifications according to surgeon's preference. Patients were divided into two groups depending on surgical management for pulmonary blood flow (modified BT shunt [BT] and non-valved RVPAC [Sano]).

Results: Fifty-four patients were included in the study (BT: 31 patients vs. Sano: 23 patients). Diastolic blood pressure during the first 24 hours postoperatively was significantly lower in the BT group (BT: 38.6 +/- 6.9 mmHg vs. Sano: 42.4 +/- 7.2 mmHg; P < 0.01) with a trend towards a higher systolic blood pressure (BT: 74.1 +/- 13.5 mmHg vs. Sano: 69.8 +/- 12.1 mmHg; P = 0.08). Mean circulatory arrest time in the BT group was significantly longer compared to the Sano patients (BT: 41 +/- 21 min vs. Sano: 25 +/- 23 min; P < 0.01). The mean hospital stay was 18.5 days for BT patients and 20 days for Sano patients ( P = 0.45). Early mortality for the total cohort was 14.8 % (n = 8) (BT 19.4 % [n = 6] vs. Sano 8.7 % [n = 2]; P = 0.12). There was no significant difference in inter-stage mortality between the two groups (BT: 18.2 % vs. Sano: 21.1 %; P = 0.47).

Conclusion: The results for both established surgical methods (BT and Sano) for the palliation of HLHS and its variants have improved over time and are reaching acceptable early mortality rates. There was a trend towards a favorable early outcome for Sano patients, which did not reach statistical significance in this study due to the low patient numbers.