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 absolute decision basis for operability in patients with ventricular septal defect/complete atrioventricular septal defect and severe pulmonary artery hypertension. Methods. Experimental design: Prospective study. Setting: Institutional practice. Patients: Eight patients with marginal operability based on preoperative Doppler echocardiography and cardiac catheterization (pulmonary-to-systemic 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 intraoperative measurements of aortic and pulmonary blood flows by electromagnetic flowmeter, Operation would be performed according to the results of direct intraoperative measurements in every patient. Results Aortic flow by direct intraoperative measurements ranged from 0.9 to 3.2 L/min/m(2), and pulmonary blood flow from 4.1 to 8.4 L/min/m(2). Pulmonary-to-aortic flow ratio was calculated at 2.1-6.6, Pulmonary vascular resistance ranged from 2.6 to 7.7 units.m(2). We assessed that all patients still had operability, and performed corrective operations. Postoperative courses corresponded with the data from the direct intraoperative measurements, Conclusions. When some clinical findings, particularly Doppler echocardiographic 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 recommend that direct intraoperative measurement of aortic and pulmonary blood flows is especially useful in decision making for the operability of patients with severe pulmonary artery hypertension.