Does Coronary Artery Size Really Matter? Turgay Celik, M.D., ∗ Atila Iyisoy, M.D., ∗ Hurkan Kursaklioglu, M.D., ∗ Sedat Kose, M.D., ∗ Selim Kilic, M.D.,‡ Basri Amasyali, M.D., ∗ and Ersoy Isik, M.D. ∗ ∗ Department of Cardiology, and ‡Department of Epidemiology, Gulhane Military Medical Academy, School of Medicine, Etlik, Ankara, Turkey Objective: To evaluate ischemia in right ventricle (RV) in patients with small caliber of right coro- nary artery (RCA). Patients and Methods: The study population consisted of 60 consecutive patients undergoing coronary angiography within 3 months. The patients were divided into three different groups according to lumen diameter of RCA and coronary dominance. Group 1, 2, and 3 consisted of patients with small diameter of RCA, dominant RCA, and dominant circumflex artery, respec- tively. RV ischemia was assessed by using pulse-wave tissue Doppler sampling obtained from RV free wall close to the lateral tricuspid annulus at the apical four-chamber view during dobutamine stress echocardiography (DSE). Results: When the mean systolic velocity percentages of increase from low to peak dose dobutamine in patients with small RCA were compared to those of other groups, statis- tically significant difference was found between group 1 and the other groups (P = 0.007 for group 1 vs group 2; P = 0.01 for group 1 vs group 3). The mean systolic velocity at peak dobutamine dose of patients with small caliber of right coronary artery was statistically lower than the other groups (P = 0.001 for group 1 vs group 2, P < 0.001 group 1 vs group 3). Conclusions: There are a group of patients with small diameter of RCA causing probable ischemia in RV and small caliber of RCA can really matter in these patients. (ECHOCARDIOGRAPHY, Volume 22, July 2005) pulse-wave tissue Doppler imaging, dobutamine stress echocardiography, right coronary artery Several reports have been published in the literature describing the poorly defined entity that is called coronary hypoplasia. 1,2 However, it is very difficult to demonstrate congenital inadequacy of coronary vessel diameter. Nor- mal coronary arterial size should be defined in terms of resting metabolic needs and coronary reserve. Epicardial coronary artery branches normally maintain an ideal lumen diameter ra- tio related to dependent myocardial bed. 3–6 Up to now any report that portrays a small coronary artery as a pathologic congenital en- tity has been met with skepticism. 7 We noticed that there was a group of pa- tients having small or hypoplastic right coro- nary artery when coronary luminograms were analyzed. The data led us to think that a small caliber of right coronary artery might cause possible ischemia in the dependent myocardial territory in this group of patients. However, the detection of the right ventricular ischemia Address for correspondence and reprint requests: Turgay Celik, M.D., Assistant Professor of Cardiology, Depart- ment of Cardiology, G¨ ulhane School of Medicine, 06018 Etlik, Ankara, Turkey. Fax: +90-312-3044250; E-mail: benturgay@yahoo.com is not easy. Both right ventricular anatomy and function are difficult to obtain from a re- liable echocardiographic examination, mainly because of a complex shape. 8,9 The analysis of right ventricular walls during ischemia by us- ing of myocardial perfusion scintigraphy is dif- ficult and somewhat operator dependent. Pulse-wave tissue Doppler (PWTD) imaging displays tissue velocity profiles of areas of inter- est with high temporal resolution. By sampling right ventricle (RV) free wall close to the tri- cuspid annulus in the apical four-chamber view, PWTD sampling estimates longitudinal RV dy- namics. 10,11 Hence, we used PWTD imaging to show RV ischemia in our study. The aim of this study was to show right ven- tricular ischemia in patients with small caliber of right coronary artery (RCA) by using PWTD sampling obtained from RV free wall close to lateral tricuspid annulus in at the apical four- chamber view during DSE. Methods Patients The study population consisted of 60 consecu- tive patients undergoing coronary angiography Vol. 22, No. 6, 2005 ECHOCARDIOGRAPHY: A Jrnl. of CV Ultrasound & Allied Tech. 479