SEX-DEPENDENT DIFFERENCES IN LEFT-VENTRICULAR FUNCTION AND STRUCTURE IN CHRONIC PRESSURE-OVERLOAD

To evaluate gender-related differences in left ventricular (LV) struct ure and function in aortic stenosis, LV biplane cineangiography, micro manometry and endomyocardial biopsies were carried out in 56 patients with aortic stenosis and normal coronary arteries. Patients were divid ed into males (M: n=35), and females (F: n=21). Sixteen normal subject s 8 M, 8 F) served as haemodynamic controls. Control biopsy data were obtained from six pre-transplantation donor hearts (3 M and 3 F). LV s ystolic function was evaluated by ejection fraction and its relationsh ip to mean systolic circumferential wall stress, diastolic function by the time constant of LV pressure decay, peak filling rates and passiv e myocardial stiffness constant. Biopsy samples were evaluated for int erstitial fibrosis, muscle fibre diameter and volume fraction of myofi brils. In a subset of 27 consecutive patients, biopsy samples were eva luated with a morphometric-morphological method, for total collagen vo lume fraction, endocardial fibrosis and the extension and thickness of orthogonal collagen fibres (cross-hatching). In patients with aortic stenosis, aortic valve area, aortic valve resistance and mean aortic p ressure gradient were comparable in males and females, whereas end-sys tolic and end-diastolic volumes were larger in males than females. Eje ction fraction was lower (56%) in males than females (64%) (P<0.05); 2 0 of 35 males and four of 21 females had depressed systolic contractil ity when assessed with regard to the relationship ejection fraction-me an systolic stress (P<0.01). Myocardial stiffness constant was higher in males than in females (P<0.01). Nine of 14 males and two of 13 fema les had endocardial fibrosis (P<0.009), whereas increased cross-hatchi ng (>1.5 grade) was present in 11 males and four females with aortic s tenosis (P<0.01). An abnormal collagen architecture was present in 13/ 14 males and 5/13 females (P<0.002). In aortic stenosis, males have a depressed systolic function and abnormal passive elastic properties wh en compared to females with valve lesions of similar severity. Changes in collagen architecture may account, at least in part, for these dif ferences.