Influence of the culprit lesion on clinical symptoms of coronary artery disease, with special emphasis on exercise data.

Abstract

Clinical symptoms have been found to correlate only poorly with the severity of the culprit lesion in coronary artery disease. The purpose of the present study was to evaluate the influence of the culprit lesion and its change during exercise on clinical symptoms in patients with this condition. Minimal luminal area was determined using biplane quantitative coronary angiography in 42 patients (aged 53 +/- 8 years) with coronary artery disease. Percent diameter stenosis and minimal luminal area and its change during exercise were assessed in all patients and compared with clinical symptoms judged according to the functional classification of the New York Heart Association (NYHA). Coronary dimensions were determined with the patient at rest, during supine bicycle exercise and after sublingual administration of 1.6 mg glyceryl trinitrate. Exercise-induced vasoconstriction of the culprit lesion was found in all patients (-14.0% at 102 W), but there was exercise-induced vasodilatation in the normal vessel segments (+13.0%). However, only minimal vasoconstriction was found in groups 1 (NYHA I: -0.5%, NS) and 2 (NYHA II: -4.7%, NS), but significant constriction in groups 3 (NYHA II-III: -18.0%, P < 0.01) and 4 (NYHA III: -31.4, P < 0.01). Vasodilatation of the normal vessel segments was similar in the four groups. The observed inverse relationship between exercise-induced changes in minimal luminal area and NYHA classification was stronger than the relationship between NYHA and minimal luminal area when the patient was at rest. There was no correlation between glyceryl trinitrate-induced vasodilatation and NYHA classification. The more severe the culprit lesion, the more pronounced the exercise-induced vasoconstriction. This effect of the culprit lesion was reflected by the clinical symptoms: the greater the exercise-induced vasoconstriction, the higher the NYHA classification. Thus the anatomy of the lesion (= severity) and the functional integrity of the endothelium (= exercise-induced vasomotion) are two major determinants of clinical symptoms.