Correlation of lipoprotein(a) levels and myocardial stress thallium scintigraphy pattern in different entities of CHD severity

Abstract

Background: Higher levels of lipoprotein(a) confer an increased risk for coronary heart disease (CHD). Apo-E genotype (APO-E) also plays a role, the APO-E epsilon 4 allele being associated with CHD. Furthermore, higher Lp(a) concentrations are correlated with APO-E epsilon 4 allele presence. The study was performed to investigate the relationship of Lp(a) and APO-E with the functional status of coronary arteries as evaluated by myocardial scintigraphy.

Patients and methods: We studied 70 patients (27 F and 43 M; mean age: 55 +/- 6 yrs.) consecutively referred for CHD, and 50 normal sex and age-matched controls. Total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, apo-AI, apo-B, Lp(a) levels (ELISA), Lp(a) isoforms (Immuno Blotting) and APO-E (PCR) were measured in all subjects. Only CHD patients underwent a myocardial tomographic stress thallium scintigraphy (201Tl-SPECT); the SPECT pattern was classified as follows: no perfusion defects (unstable angina group = 1), reversible defects at stress images (ischemia group = 2), fixed defects (infarction group = 3).

Results: Lp(a) medians were significantly higher than controls in group 1 (p < 0.05), 2 (p < 0.001) and 3 (p = 0.00). Low molecular weight isoforms (B, S1, S2) were significantly more frequent in all CHD-patients vs. controls (p < 0.05), whereas APO-E genotypes did not differ among controls and patients. Multiple regression analysis showed family history (p < 0.001) to be the only independent predictive variable of CHD severity correlated to the scintigraphic pattern.

Conclusion: Among the considered biological parameters in our patients only Lp(a) plasma levels are related to the entity of ischemic cardiac wall damage as evaluated by 201Tl-SPECT.