The Gradient in Pressure Across the Pulmonary Vascular Bed During Diastole

Abstract

By means of right and left heart catheterization 70 patients with congenital or acquired heart disease were examined to determine whether or not a gradient in pressure existed between the pulmonary artery and the left ventricle at the end of diastole. In the absence of mitral valvular obstruction in 56 patients there was a statistically significant correlation of pulmonary artery diastolic, left ventricular end-diastolic, and left atrial mean pressures less than 15 mm Hg which was independent of heart rate. Diastolic pressures at identical levels as high as 40 mm Hg were demonstrated in the presence of aortic insufficiency without left ventricular failure, and as high as 47 mm Hg during pulmonary edema in one patient with aortic stenosis and insufficiency. A diastolic gradient in pressure between the pulmonary artery and the left ventricle existed in 14 patients with pulmonary hypertension. These patients all had congenital intracardiac shunts and it may be assumed that they had some obstruction in the pulmonary vascular bed. These findings suggest that within defined limits friction across the pulmonary vascular bed is so small that a state of pressure equilibrium exists at the end of diastole. When the limits are met clinically, the pressures in the pulmonary artery and in the left ventricle at the end of diastole are identical.

Effects of increasing left ventricular filling pressure in patients with acute myocardial infarction

“…Also the change in ventricular performance as a function of heart rate alterations (treppe phenomenon) would have no important effect in this study as the heart rate in individual patients varied little at all during infusion. Finally, the pulmonary artery end-diastolic pressure has been shown to be a reliable index of left ventricular end-diastolic pressure assuming a normal mitral valve and normal pulmonary vascular resistance (30). The two pressures were recorded simultaneously on 20 occasions in four patients in this study, in three patients before infusion, and in one during dextran infusion.…”

Determinants of pulmonary blood volume

“…The diastolic pressures in these five patients ranged from 7 to 10 mm of Hg. Since Kaltman, Herbert, Conroy, and Kossmann have reported that in this range pulmonary artery diastolic pressure varies little from left atrial pressure, these patients were included in the series (18).…”

Relationship between Pulmonary Artery End-Diastolic Pressure and Left Ventricular Filling Pressure in Patients in Shock

“…The agents were infused in increasing amounts depending on clinical response (i.e., increases in systemic pressure, urine flow, improved sensorium, cardiac output), the limiting factors being an undue increase in heart rate or increased ventricular irritability. Four patients were treated with norepinephrine (4-12 ug/min), three with isoproterenol (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) gg/min) and one patient in the latter group received 5 mg of glucagon (table 3). Two patients were studied before and after intravenous administration of 80 mg of ethacrynic acid while another subject was studied before and 10 min after administration of a 250-ml volume challenge.…”