Monitoring pulmonary arterial pressure in coronary-artery disease

Abstract

To delineate the indications for pulmonary arterial pressure monitoring, the relationship between central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP) was examined in 30 patients with coronary-artery disease and ventricular dysfunction (ejection fractions ranging from 0.26 to 0.84) prior to, during, and after coronary-artery surgery. For each patient, 30 simultaneous measurements of CVP and PCWP were made during a 36-hour period that included the awake state, the anesthetized state with and without surgery, before and after pericardiotomy, before and after cardiopulmonary bypass, and one, four, eight, and 24 hours after operation. At each point, changes in filling pressures were acutely induced by changing body position to alter venous retrun. The CVPs ranged from 0 to 19 torr, and the PCWPs from 0 to 31 torr. The CVP and the PCWP correlated well (r = 0.89) during all measurement periods for patients who had ejection fractions greater than 0.50 without angiographically demonstrable ventricular dyssynergy preoperatively. Changes in CVP (ΔCVP) and PCWP (ΔPCWP) over the 36-hour period also correlated well (r - 0.94). Normality (abnormality) of the CVP was predictive of normality (abnormality) of the PCWP for more than 96 per cent of the 450 data points. On the other hand, for patients with ejection fractions less than 0.40 or with dyssynergy, the CVP did not correlate with the PCWP (r = 0.24), and ΔCVP did not correlate with ΔPCWP (r = 0.04). Normality (abnormality) of the CVP was predictive of normality (abnormality) of the PCWP for less than 62 per cent of the 450 data points. This study has defined subclasses of patients with coronary-artery disease for whom pulmonary arterial pressure monitoring is indicated prior to, during, and following coronary-artery surgery.