Right ventricular ejection fraction in the preoperative risk evaluation of candidates for pulmonary resection

The major determinants of postoperative morbidity and mortality after lung resection are the physiologic and functional statuses of the pulmonary and cardiac systems. In our previous study, serial measurements of right ventricular performance after pulmonary resection demonstrated significant right ventricular dysfunction in the postoperative period. This study evaluates the preoperative measurement of right ventricular ejection fraction as a predictor of postoperative complications. In addition to conventional cardiopulmonary functional tests, right ventricular function was assessed with a thermodilution technique at rest and during exercise in 18 patients before and 3 weeks after lobectomy or pneumonectomy. The patients were grouped according to severity of right ventricular functional defect: right ventricular ejection fraction of at least 45% (group Ia, n = 8), right ventricular ejection fraction less than 45% (group Ib, n = 10), exercise-induced increases in right ventricular ejection fraction (group IIa, n = 8), and exercise-induced decreases in right ventricular ejection fraction (group IIb, n = 10). Postoperative cardiopulmonary morbidity was recorded for two patients (25%) in group Ia, three patients (30%) in group Ib, no patients (0%) in group IIa, and five patients (50%) in group IIb. Postoperative hospital stay was 28.9 +/- 8.5 days in group Ia, 29.9 +/- 20.2 days in group Ib, 19.4 +/- 8.0 days in group IIa, and 37.5 +/- 15.9 days in group IIb (p < 0.05, group IIa vs group IIb). Although resection-induced changes in forced expiratory volume in 1 second did not differ significantly between group Ia and group Ib, these values appeared to be increased in groups IIa (not statistically significant) and IIb (significantly, p < 0.05). The measured postoperative values of forced expiratory volume in 1 second and vital capacity were significantly higher than the predicted postoperative values (p < 0.05) in group IIa, but not in groups Ia, Ib, and IIb. We conclude that evaluation of right ventricular performance is useful in determining which patients are at increased risk for medical complications after lung resection. Exercise-induced change in right ventricular ejection fraction may be a better indicator of high risk among candidates for pulmonary resection than the absolute value of this parameter.