Influence of the location of left anterior descending coronary artery stenosis on left ventricular function during exercise.

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Abstract
Whether a stenosis of a coronary artery located proximally caused greater deterioration of left ventricular function than a stenosis of a similar magnitude located more distally in the artery was determined. Patients (26) with isolated left anterior descending coronary artery (LAD) lesions documented by cardiac catheterization were studied by radionuclide angiocardiography (RNA) at rest and during exercise on a bicycle ergometer. Thirteen patients (9 males and 4 females) had a proximal lesion of the LAD averaging 91 .+-. 11% of the diameter of the lumen (group 1) and 13 patients (8 males and 5 females) had a distal lesion averaging 88 .+-. 12% of the lumen (group 2). The mean age of group 1 was 49 .+-. 9 yr and the mean age of group 2 was 48 .+-. 9 yr. In group 1, the ejection fraction decreased from 63 .+-. 8% to 55 .+-. 11% (P = 0.02), left ventricular end-diastolic volume (EDV) increased from 130 .+-. 32 ml to 174 .+-. 34 ml (P = 0.001) and left ventricular end-systolic volume (ESV) increased from 49 .+-. 16 ml to 80 .+-. 26 ml (P = 0.001) during exercise. In group 2, the ejection fraction and ESV showed no significant change during exercise. In this group, the left ventricular EDV increased from 117 .+-. 28 ml to 140 .+-. 37 ml (P = 0.04) during exercise. The 2 groups showed no significant hemodynamic differences during the rest studies, but group 1 showed significantly lower ejection fraction and higher EDV and ESV during exercise. A stenotic lesion located at a more proximal level of the coronary arterial system reduces blood flow in a larger area of myocardium, resulting in a more pronounced ischemic response to exercise than a similar lesion located more distally.