Cardiac Output Response to Exercise in Patients with Inferior Vena Caval Ligation

Studies were carried out to determine whether hemodynamic alterations may follow inferior vena caval (IVC) ligation. Five patients, aged 29 to 49 years, who had been operated upon 2 to 5 years previously, and five normal controls, aged 39 to 44 years, were studied at rest and during graded submaximal treadmill exercise. There were no significant differences in heart rate, right atrial pressure, brachial arterial pressure, oxygen consumption, or cardiac output between the patients and normals in the supine rest and head-up tilt positions. During treadmill exercise the heart rate and oxygen consumption were comparable in the two groups, but the cardiac output response was definitely diminished in the patient group. This was reflected in the exercise factor, that is, the increase in cardiac output per 100 ml increase in oxygen consumption. The mean exercise factor was 406 ml for the patient group and 726 ml for the controls, a significant difference ( P < 0.001). It is concluded that the cardiac output response to upright exercise may be impaired in patients with IVC ligation. Inadequate venous return following IVC ligation may explain the persistent postoperative exertional dyspnea that has been noted in our patients.