Ischaemia-Driven Optimal Therapeutic Approach in Asymptomatic Patients with High Cardiovascular Risk: The Value of Clinical, Laboratory and Myocardial Spect Imaging Findings

Abstract

We wanted to evaluate the presense of myocardial ischaemia in asymptomatic patients with high cardiovascular risk, the influencing clinical and laboratory factors and the impact of ischaemia on final management decision. We evaluated 60 asymptomatic patients with high CV risk, who underwent SPECT myocardial perfusion imaging (MPI) for detection of suspected CAD. We used the 17 segment model for quantitative and semiquantitative scan perfusion and function analysis using perfusion scores. All patients had full blood laboratory analyses including lipid values, presence of albuminuria, rest and stress ECG. Logistic regression analysis was used to assess the impact of clinical and laboratory parameters on myocardial ischaemia prevalence. Stress-inducible ischaemia was found in 19 pts (33%), fixed defects were found in 13% and mixed defects in 9% of cases. The average ischaemia amount was 10%. Mild ischaemia was found in 12 patients (64%)--summed stress score (SDS)<4, moderate ischaemia in 5 patients (26%)--SDS 5-7 and severely abnormal scans in 2 patients (10%)--SDS>7. Severe ischaemia was only related to the duration of diabetes. Six pts with severe ischaemia had ST depression>2 mm on stress study, and a higher wall motion index and LVEF fall>5% during stress study (p<0.01). Stepwise logistic regression analysis for prediction of stress-induced ischaemia showed OR 2.4 (95% CI 1.7-3.6) for stress-induced ECG changes and OR 3.9 for presence of DM over 10 y (95% CI 2.3-6.6). Seven patients with ischaemia>10%, were referred for coronary angiography. MPI is a valuable method for preclinical assessment of myocardial ischaemia in patients with high CV risk, which can improve prognosis and guide treatment decision.