Influence of Catheter Tip Position on Pulmonary Wedge Pressures

Abstract

Pulmonary artery wedge pressures and wedge pulmonary arteriograms were obtained in 68 patients with either mitral stenosis, congenital heart disease, or no demonstrable heart disease. The arteriogram defines five catheter tip positions in the wedged artery. Tip positions unfavorable for left atrial pressure transmission occurred in 20 of the 68 trials and accounted for 19 of the 31 unsatisfactory tracings. Favorable tip positions were found in 48 instances and resulted in 36 phasic tracings. Unsatisfactory tracings in patients with pulmonary hypertension and congenital heart disease are shown to result primarily from unfavorable catheter tip positions. In these patients structural changes in the larger pulmonary arteries may prevent proper wedging. Increased left atrial pressure assures transmission of a cyclic left atrial pulse to a properly impacted catheter regardless of the degree of associated pulmonary hypertension. It is concluded that the fortuitous position assumed by the catheter tip in the wedged artery and the level of the left atrial pressure are factors of major importance in the satisfactory recording of the left atrial pulse curve by the wedged catheter.