Intravascular ultrasound study and evidence of pathological coronary flow reserve in patients with isolated coronary artery aneurysms.

OBJECTIVES: Isolated coronary artery aneurysms (CA) are defined as non-obstructive lesions with luminal dilation > or =2-fold of normal coronary diameters. METHODS: A coronary sinus study with incremental atrial pacing was performed in 19 patients with bilateral fusiform CA to investigate myocardial ischemia. Intravascular ultrasound was performed to characterize the lesions morphology. The average peak velocity in the aneurysmatic segment of the left anterior descending artery was simultaneously measured by a Doppler flow wire. Coronary flow volumes, vascular resistances and flow reserve after administration of papaverin were calculated. Ten patients without heart disease served as a control group (CG). RESULTS: Intravascular ultrasound revealed large true CA with a cross-sectional area of 34.2 +/- 4.1 mm(2) and only slight atherosclerosis. Exercise-induced myocardial ischemia was found in CA presenting with a cardiac lactate production and an only 1.6-fold increase in coronary blood flow. A significant smaller coronary flow reserve of 1.51 was revealed in CA when compared with CG (2.86, P < 0.02) corresponding to a coronary vascular resistance of 0.59 versus 0.35 (P < 0.03) mmHg (ml/min) after papaverin. CONCLUSIONS: Coronary artery aneurysms were unequivocally identified as an entity of ischemic non-obstructive coronary artery disease with a markedly reduced flow reserve.

Evidence of pathological coronary flow patterns in patients with isolated coronary artery aneurysms.

OBJECTIVES: Aim of our study was to evaluate the coronary flow patterns and therapeutic effects of nitroglycerin (NTG) in patients with isolated large coronary artery aneurysms (CA). CA are defined as nonobstructive lesions of the epicardial coronary arteries with a luminal dilation >or=two-fold of the normal diameters. The pathophysiology of a potential coronary insufficiency in this entity is still unknown. METHODS: A coronary sinus study with incremental atrial pacing before and after the administration of 0.2 mg NTG was performed in 19 patients with bilateral large fusiform nonstenotic CA to evaluate an exercise-induced myocardial ischemia. The average peak velocity in the aneurysmatic segment of the proximal left anterior descending artery was simultaneously measured by a 14/1000 inch Doppler flow wire. The coronary flow volumes and vascular resistances were calculated. RESULTS: Evidence of exercise-induced myocardial ischemia was found in all patients presenting with a frank cardiac lactate production (10.2+/-3.3%) which was significantly aggravated by NTG (26.0+/-7.5%, P<0.003). 0.2 mg NTG provoked a long-lasting and significant decrease in coronary flow volume (from 140.2+/-34.2 to 91.2+/-21.8 ml/min, P<0.002), a marked increase in coronary vascular resistance (from 0.62 to 0.92 mmHG x ml/min(-1), P<0.002) and an inadequate increase in coronary flow volume under cardiac pacing. CONCLUSION: CA were identified as an entity of nonobstructive ischemic coronary artery disease with an exercise-induced myocardial ischemia and impaired flow volume. NTG exerted an adverse vasoactive effect in CA.