Gender differences in coronary artery size per 100 g of left ventricular mass in a population without cardiac disease

To determine whether there is a gender difference in coronary artery size normalised for left ventricular (LV) mass.

Small coronary artery caliber may play a role as a risk factor for coronary artery disease in women. However, the existence of a gender difference in coronary artery size is controversial. Furthermore, coronary artery size ought to be normalised for LV mass, since there is a theoretical relation of coronary artery size to LV mass according to the law of minimum viscous energy loss for the transport of blood in the coronary circulation.

In 200 individuals (100 women) without cardiac disease and with normal Doppler echocardiography, left main (LCA) and right coronary artery (RCA) size were determined using transoesophageal echocardiography. LV mass was assessed by transgastric M-mode echocardiography.

Age (44 +/- 15 years in women; 41 +/- 16 years in men), the presence of non-cardiac diseases, cardiovascular risk factors and medication were similar in women and men. LV mass in women was lower than in men (148 +/- 36 g, 189 +/- 45 g; p < 0.0001). LCA and RCA cross-sectional areas in women were smaller than those in men (LCA: 10 +/- 3 and 16 +/- 5 mm2, p < 0.0001; RCA: 4 +/- 2 and 7 +/- 3 mm2, p < 0.0001, respectively). LCA and RCA cross-sectional areas of women were smaller even after normalisation for LV mass (LCA: 7 +/- 3 and 9 +/- 3 mm2/100 g LV mass, p < 0.0001; RCA: 3 +/- 1 and 4 +/- 1 mm2/100 g LV mass, p = 0.002, respectively). LCA caliber of women ranged below the theoretically expected size according to the law of minimum viscous energy loss for the transport of blood in the coronary circulation, whereas those of men tended to be above it.

In a population without cardiac disease, women have smaller coronary artery size even after normalisation for left ventricular mass.