Left ventricular contractile state after surgical correction of tetralogy of Fallot: Risk factors for late left ventricular dysfunction

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Abstract
The purpose of this study was to analyze potential “risk-factors” for late left ventricular dysfunction after surgical correction of Fallot's tetralogy (FT). As the ejection-phase indices cannot distinguish abnormalities of contractility from altered loading conditions, the slope values of the end-systolic pressure-length and stress-shortening relationships were analyzed by increasing afterload. Thirty-two patients were studied after surgical correction of FT in infancy. The age at investigation was 19.2±5.6 years, total correction had been performed at the age of 7.7±3.3 years. In 20 patients a one-stage operation was performed, and in 12 patients a two-stage correction. The control group consisted of 30 healthy volunteers, aged 18–30 years. The following potential risk factors for left ventricular dysfunction were evaluated: one-stage vs. two-stage correction, age at total correction, preoperative systemic oxygen saturation, preoperative hematocrit, occurrence of hypoxic spells, preoperative ratio of left-to-right ventricular peak systolic pressure, and preoperative ratio of left-to-right ventricular end-diastolic volume. In most patients the baseline data for end-systolic wall stress lay outside the normal range, indicating abnormal loading conditions. Thus, analysis of load-independent indices of the contractile state seems to be mandatory in these patients. Our data show that the severity of preoperative hypoxemia is an important risk factor for late dysfunction of the left ventricle (pp<0.01). No influence of preoperative hypoxic spells, the need for a palliative aortopulmonary shunt, or the age at surgical correction on the postoperative contractile state was demonstrated. The latter may have been due to the fact that none of the patients were operated on within the first 2 years of life.