Direct intraoperative measurements of aortic and pulmonary blood flows in patients with severe pulmonary artery hypertension

Background. Evaluate the significance of direct intraoperative measurements of aortic and pulmonary blood flows by electromagnetic flowmeter as an abs olute decision basis for operability in patients with ventricular septal de fect/complete atrioventricular septal defect and severe pulmonary artery hy pertension. Methods. Experimental design: Prospective study. Setting: Institutional pra ctice. Patients: Eight patients with marginal operability based on preopera tive Doppler echocardiography and cardiac catheterization (pulmonary-to-sys temic flow ratio=1.1-2.3, pulmonary-to-systemic resistance ratio=0.34-0.91, and pulmonary vascular resistance=4.6-18.2 units.m(2)) underwent direct in traoperative measurements of aortic and pulmonary blood flows by electromag netic flowmeter, Operation would be performed according to the results of d irect intraoperative measurements in every patient. Results Aortic flow by direct intraoperative measurements ranged from 0.9 t o 3.2 L/min/m(2), and pulmonary blood flow from 4.1 to 8.4 L/min/m(2). Pulm onary-to-aortic flow ratio was calculated at 2.1-6.6, Pulmonary vascular re sistance ranged from 2.6 to 7.7 units.m(2). We assessed that all patients s till had operability, and performed corrective operations. Postoperative co urses corresponded with the data from the direct intraoperative measurement s, Conclusions. When some clinical findings, particularly Doppler echocardiogr aphic findings, of these patients are slightly in favor of reversibility of pulmonary vascular disease despite discrepant data of preoperative cardiac catheterization under a tight control of carbon dioxide tension, we recomm end that direct intraoperative measurement of aortic and pulmonary blood fl ows is especially useful in decision making for the operability of patients with severe pulmonary artery hypertension.