Association of lipoprotein(a) levels and apolipoprotein(a) phenotypes with coronary heart disease in patients with essential hypertension

Background Besides hypertension, several cardiovascular risk factors can play a role in the development of coronary heart disease (CHD) in hypertensive patients. Lipoprotein(a) [Lp(a)] is an important and independent cardiovascular risk factor, but its role in the development of CHD in hypertensives has not been studied. Objective To investigate whether or not Lp(a) levels and isoforms of apolipoprotein(a) [apo(a)] are predictors of CHD in patients with essential hypertension. Methods Lp(a) levels and apo(a) polymorphism were evaluated in 249 patients with essential hypertension, in 142 non-hypertensive patients with CHD and in 264 healthy controls. Results Hypertensives with CHD (n = 61) had Lp(a) levels [19 (range 0.5-73.5) versus 7 mg/dl (range 0-83.5), P < 0.001] and a percentage of apo(a) isoforms of low (< 655 kDa) relative molecular mass (RMM, 59.2 versus 25.9%, P < 0.001) higher than did those without CHD (n = 188). Moreover, there were more subjects with at least one apo(a) isoform of low RMM in the subgroup of patients with CHD than there were in that of those without CHD (80.3 versus 30.8%, P < 0.001), Lp(a) levels and apo(a) polymorphism did not differ significantly between hypertensive and non-hypertensive patients with CHD, Stepwise regression analysis indicated that high Lp(a) levels (P = 0.002073) and particularly the presence of at least one apo(a) isoform of low RMM (P < 0.000001) are strong predictors of CHD in hypertensive patients. Conclusions Our data show that high Lp(a) levels and the presence of at least one apo(a) isoform of low RMM are strong and independent genetic risk factors for CHD in hypertensive patients. These findings suggest that Lp(a) and apo(a) isoforms should be assessed together with other cardiovascular risk factors to establish the overall CHD risk status of each hypertensive patient.