Sex differences in coronary artery size assessed by intravascular ultrasound

Background Women have worse outcomes after myocardial infarction and corona ry revascularization. The explanations are likely multifactorial but may in clude smaller coronary artery size. Smaller luminal diameter has been confi rmed angiographically; however, because of possible confounding effects of coronary remodeling, angiographically silent atherosclerosis, and body size , it is unclear if there is a true sex influence on arterial size. Methods We performed intravascular ultrasound on left main (LM) and proxima l left anterior descending (LAD) coronary artery segments that were free of significant atherosclerosis in 50 men and 25 women. Arterial and luminal a reas were measured by planimetry and corrected for body surface area. We ev aluated associations between sex and coronary dimensions with univariate an d then multiple linear regression analyses. Results Mean uncorrected LM and LAD arterial areas were smaller in women th an in men (21.53 vs 26.95 mm(2), P < .001, and 14.68 vs 19.94 mm(2), P = .0 02, respectively), as were mean LM and LAD luminal areas (15.94 vs 18.79 mm (2), P = .020, and 10.13 vs 12.71 mm(2), P = .036, respectively). In multiv ariate models accounting for body surface area and controlling for other fa ctors, sex independently predicted corrected LM and LAD arterial area. In a nalyses that additionally controlled For plaque area, sex independently pre dicted corrected LAD luminal area. Conclusions LM and LAD arteries are smaller in women, independent of body s ize. This suggests an intrinsic sex effect on coronary dimensions. Future s tudies should investigate underlying mechanisms because hey may lead to nov el therapeutic strategies and improved outcomes for women with coronary art ery disease.