Circulation, Vol 77, 613-624, Copyright © 1988 by American Heart Association
ES Monrad, OM Hess, T Murakami, H Nonogi, WJ Corin and HP Krayenbuehl
We studied the hemodynamic response to supine bicycle exercise in 20
patients late (10 +/- 2 years) after aortic valve replacement (for aortic
stenosis in 12 patients, aortic insufficiency in six patients, and for
combined stenosis and insufficiency in two patients). The pulmonary artery
wedge pressure was obtained with a pulmonary artery balloon catheter, and
left ventriculography was performed by digital- subtraction angiography
after injection of radiographic contrast into the pulmonary artery. These
patients were compared with 11 control subjects with no or minimal cardiac
disease studied routinely for evaluation of chest pain in whom left
ventricular end-diastolic pressure and a direct contrast ventriculogram
were obtained. Compared with the control population, the study population
had similar left heart filling pressures (7 +/- 3 vs 9 +/- 3 mm Hg, NS),
but higher left ventricular ejection fractions (75 +/- 7% vs 67 +/- 7%, p
less than .02) and higher left ventricular muscle mass indexes (106 +/- 28
vs 85 +/- 9 g/m2, p less than .01). Elevated myocardial muscle mass led to
lower systolic wall stress in the study population than in the control
subjects (254 +/- 65 vs 320 +/- 49 10(3).dynes/cm2, p less than .01) and
might explain the higher ejection fraction observed. Fourteen patients had
a normal response to exercise (with left heart filling pressures of 16 +/-
4 vs 18 +/- 2 mm Hg for control subjects, NS; and left ventricular ejection
fraction of 77 +/- 8% vs 73 +/- 5% for control subjects, NS). However,
while the remaining six patients had a normal exercise left ventricular
ejection fraction (72 +/- 9%, NS), they had an abnormal rise in left heart
filling pressure (33 +/- 8 mm Hg, p less than .01). Preoperatively these
patients also had higher left ventricular mid- and end-diastolic pressures
at similar diastolic volumes, suggesting a decrease in chamber compliance.
Thus, late after aortic valve replacement there is a subgroup of patients
who, despite normal hemodynamics and normal left ventricular systolic
function as assessed by the left ventricular ejection fraction at rest,
have an abnormal response to exercise characterized primarily by a
substantial rise in left heart filling pressures. Preoperatively this group
also has a decrease in diastolic chamber compliance despite nearly normal
left ventricular ejection fractions. This abnormality appears to result
from a primary derangement of diastolic function that is not evident at
rest.
ARTICLES
Abnormal exercise hemodynamics in patients with normal systolic function late after aortic valve replacement
Division of Cardiology, University Hospital, Zurich, Switzerland.
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