Myocardial ischaemia in systemic lupus erythematosus: detection and clinical relevance.

Background: Severe cardiovascular complications are among the most important causes of mortality in systemic lupus erythematosus (SLE) patients.
Aim: To assess the usefulness of echocardiography, ECG, and coronary artery calcium scoring (CACS) in the detection of myocardial ischaemia in SLE patients compared to single photon emission computerised tomography (SPECT) and to assess their five-year follow-up.
Methods: In 50 consecutive SLE patients (mean age 39.2 ± 12.9 years, 90% female), clinical assessment, resting and exercise ECG and echocardiography, multidetector computed tomography - based CACS and SPECT studies (Tc-99m sestamibi) were performed. Patients were then followed for five years.
Results: SPECT revealed perfusion defects in 25 (50%) patients; persistent defects in 18 (36%) and exercise-induced defects in seven (14%) subjects. No typical ischaemic heart disease clinical symptoms, signs of ischaemia in resting ECG, or left ventricular contractility impairment in echocardiography were observed. Signs of ischaemia in exercise ECG were found in 17 (34%) patients. The CACS ranged from 1 to 843.2 (median 23.15), and coronary calcifications were observed in 12 (24%) patients. Compared to the SPECT study, exercise ECG had 68% sensitivity and 100% specificity in detecting myocardial ischaemia, while CACS had only 28% sensitivity and 58% specificity. During follow-up, one patient who showed myocardial perfusion defects and the highest calcium score (843.2) at baseline, developed CCS II class symptoms of myocardial ischaemia. Coronary angiography was not performed because of severe anaemia; the patient died three months later. In two other patients with perfusion defects and calcium deposits at baseline, CCS I class symptoms were observed; coronary angiography showed only thin calcified coronary plaques that were haemodynamically insignificant.
Conclusions: In about half of relatively young, mostly female, SLE patients, SPECT shows myocardial perfusion defects, with coronary calcifications present in one quarter of them. While ECG and echocardiography may not reveal any pathology, ECG exercise test can identify these patients with high specificity. In patients with a negative SPECT, the short-term prognosis is good, while in patients with perfusion defects and coronary calcifications, the clinical symptoms of myocardial ischaemia could occurr. However, at a low calcium score ( < 150), the short-term risk of significant atherosclerosis progression is low.