Gender disparity in radial and femoral arterial size: an ultrasound study

Abstract

Sir: Arterial catheterization is a common intensive care unit (ICU) procedure. We have previously found that women are more likely to fail catheter attempts [1]. Few prior studies have investigated gender differences in arterial size. Men have larger left main and left anterior descending (LAD) coronary arteries, independently of body surface area (BSA) [2]. Herity et al. [3] found increased LAD size in hearts transplanted from female donors to male recipients. Krejza et al. found men have larger carotid arteries [4]. Babuccu et al. [5] studied the diameters of radial, thoracodorsal, and dorsalis pedis arteries in pediatric patients and found that age, weight, and male gender are associated with larger size. The radial and femoral arteries are commonly used for arterial catheter placement. We studied arterial size in these locations to determine whether men have larger arteries. The study was conducted over a 4-month period beginning 11 May 2005 in the medical ICU of an urban teaching hospital. The study was approved by the Beth Israel Medical Center Institutional Review Board and was performed in accordance with the ethical standards of the 1964 Declaration of Helsinki. The requirement for written informed consent was waived. An Acuson Cypress 7.5 MHz ultrasound probe with 0.1-mm resolution was used (Siemens, Malvern, Pa., USA). Arterial diameter was measured in the transverse orientation of arterial diameter in systole. Measurements were taken during three different cardiac cycles and averaged. Radial arteries were measured 2 cm proximal to the distal wrist crease. Femoral arteries were measured one-third of the way from the pubic symphysis to the superior iliac crest. Based on clinical observations prior to the study we estimated that men’s femoral arteries would be 1 mm larger than women’s, and that their radial arteries would be 0.5 mm larger. Setting α at 5% and β at 20%, we calculated that 30 patients would be required to detect this difference in femoral arteries, and 36 patients would be required for radial arteries. Associations between demographic characteristics and arterial size were assessed by