Simultaneous transesophageal doppler estimation of coronary flow reserve in the left descending artery and coronary sinus in the differentiation of proximal and nonproximal left descending artery stenoses

Abstract

The aim of our study was the differentiation of proximal and non-proximal left descending artery (LDA) stenoses with simultaneous assessment of coronary flow reserve (CFR) in the LDA and coronary sinus (CS) in CAD patients with single-vessel LDA stenosis using multiplane transesophageal echocardlography. Methods: We studied 17 men (mean age 46~7 years) with over 50% single-vessel LDA stenosis, confirmed with quantitative coronary angiography. Nine patients with over 50% smgle-vessel proximal LDA stenosis were included in group la. Eight patients with over 50% stenosis of the LDA mid and/or distal third composed group lb. The control group (II) consisted of 25 healthy volunteers (men, mean age 35*5 years). Transesophageal Doppler assessment of coronary blood flow in proximal LDA and CS was performed at baseline and after intravenous dipyridamole (0,56 mg/kg for 4 minutes) using ultrasound diagnostic systems HDI 5000 SonoCT and Ultramark 9 HDI CV (Philips-ATL). CFR was calculated as the ratio of hyperemic to baseline peak diastolic velocities I” the LDA and CS. Results: The baseline peak diastolic velocltvas of blood flow in the LDA and CS did not differ significantly in groups la, lb and II, and were 52+27 cm/s, 39*13 cm/s. 37+11 cm/s for the LDA, and 32ill cm/s, 34+8 cm/s. 3&l 1 cm/s for the CS, respectively. In group la CFR in the LDA was significantly reduced, compared to groups lb and II, and made 1.87eO.43. 3.23el.35 and 3.51kO.79, p<O.Ol, respectively. We revealed a reverse correlation between the LDA stenosis area and CFR in this artery (r=-0.60, pcO.001). CFR in the LDA <2 had a positive predictive accuracy of 83% in the diagnostics of proxlmal stenoses. A signtficant diminution of CFR in the CS was determined in CAD patients of both the groups when compared with healthy volunteers and was 1.74eO.53, 1.63*0.30. 2.56i0.87 for groups la, lb, II, respectively (p la-11 cO,O5, p lb-11 <0,05, p la-lb =ns). CFR ~2 in the CS had a positive predictive accuracy of 63% in the diagnosttcs of LDA stenosis of any localization. Thus. reduced CFR in the LDA is a predictor of proximal LDA stenosis. Reduced CFR in the CS IS a predictor of stenosis in both the proximal and non-proximal LDA segments.