Improved hemodynamics and outcome after modified Norwood operation on the beating heart.

BACKGROUND

Recently introduced cardiopulmonary bypass techniques to avoid circulatory arrest were proposed to improve organ function of the modified Norwood operation for hypoplastic left heart syndrome. This study compares postoperative hemodynamics and survival in patients who underwent Norwood procedure on the beating heart to those operated on with cardioplegic cardiac arrest.

METHODS

Between October 2002 and January 2005, 26 consecutive patients aged 4 to 275 days (median, 9 days) and weighing 2.9 to 4.4 kg (median, 3.4 kg) underwent Norwood palliation: 13 with continuous coronary and systemic perfusion (group 1), and 13 with only continuous systemic perfusion but arrested heart (group 2). Standard hemodynamic measurements, lactate levels, arterial and superior vena cava oxygen saturations, and inotropic agents required for postoperative hours 0, 6, 12, 18, 24, and 48 were retrospectively analyzed. For univariate comparison of different variables, chi2 test, Fisher's exact test, or Student's t test was used as appropriate.

RESULTS

In group 1 significantly higher mean arterial pressure (53 +/- 0.8 versus 50 +/- 1.2 mm Hg; p = 0.04), higher central oxygen saturation (54% +/- 1.1% versus 50% +/- 1.5%; p = 0.03), higher urinary output (5.3 +/- 0.4 versus 4.4 +/- 0.4 mL.kg(-1).h(-1); p = 0.09), lower lactate levels (2.4 +/- 0.1 versus 4.1 +/- 0.6 mmol/L; p = 0.009) with lower doses of norepinephrine (0.03 +/- 0.004 versus 0.14 +/- 0.03 microg.kg(-1).min(-1); p = 0.002) were recognized. Hospital mortality was 0% in group 1 and 38.5% (5 of 13) in group 2 (p = 0.04). Univariate analysis revealed mortality to be also correlated with preoperative intubation (p = 0.02) and the use of preoperative inotropic agents (p = 0.03).

CONCLUSIONS

Avoidance of cardiac arrest by means of continuous coronary perfusion in addition to continuous systemic perfusion significantly improves postoperative hemodynamic performance and thus helps to reduce hospital mortality after the modified Norwood procedure.