Coronary artery disease (CAD) is the major cause of death in both sexes in the western world. In men with chest pain the diagnostic methods are more useful than in women. An exercise test is considered less reliable in women, mostly due to a high percentage offalse positive tests. Furthermore, 20-40% of women with typical angina have normal vessels at coronary angiography. The mechanisms behind the chest pain in these patients are unknown, but could be due to disturbances in endothelial, thrombogenetic and/or fibrinolytic function.
In a prospective multicentre trial we examined 200 postmenopausal women with unstable CAD and 101 healthy controls. At coronary angiography 15% had normal vessels, 14% had non-significant atherosclerosis and 71% had at least one significant stenosis.
The diagnostic information from basic clinical parameters, ECG and an early exercise test were evaluated. The prevalence of coronary atherosclerosis was high, 85%, and the early exercise test was just as valuable as in men for identifying patients with significant CAD.
Endothelial markers, cyclic GMP (cGMP) and immunoreactive endothelin (irET), were analysed regarding presence or not of coronary atherosclerosis. Patients with normal vessels had low levels of ir-Ef, indicating different mechanisms for ischemia/angina in these patients compared with patients with atherosclerosis. No differences were found regarding cGMP, unless the patient had long-term nitroglycerin treatment, which increased plasma cGMP. Patients with exerciseinduced ischemia had higher cGMP plasma levels compared to those without. This may reflect a general compensatory mechanism.
New lipid variables, apolipoproteins and lipoprotein particles, were no better than the routine lipid examination in separating women with and without coronary atherosclerosis, and the measurement of apolipoproteins and lipoprotein particles on the basis of diagnostic accuracy alone is not justified. Also, elevated triglycerides was most pronounced in women with unstable CAD and coronary atherosclerosis.
Plasma total homocysteine (tHey) is considered a risk factor for CAD, but the relationship between tHey and well-defined CAD in women is still unclear. Mild hyperhomocysteinemia was not related to the risk of unstable CAD in postmenopausal women. Our study stresses the importance of adjusting tHey for the covariates, i.e. age and serum values of folate, vitamin Bl2 and creatinine.
Fibrinolytic and coagulation variables did neither reveal signs of disturbed fibrinolysis nor were in favour of a hypercoagulable/hyperthrombotic state in patients with unstable CAD and normal vessels.
In summary, the prevalence of coronary atherosclerosis in postmenopausal women with signs and symptoms of unstable CAD is high. An early exercise test together with basic clinical parameters is a valuable diagnostic tool. Although there were differences in biochemical markers between patients with and without coronary atherosclerosis, the overlapping between the groups was high. No clinically useful test to separate these two groups was found. Patients with normal vessels were much alike the control group and it is still unclear whether these patients have CAD without atherosclerosis or another mechanism for their chest pain.
Linköping: Linköpings universitet , 2000. , 105 p.
2000-02-04, Berzeliussalen, Universitetssjukhuset, Linköping, 09:00 (Swedish)