Association of serum lipoprotein(a) levels and apolipoprotein(a) size polymorphism with target-organ damage in arterial hypertension

Objective.-To investigate the association between lipoprotein(a) [Lp(a)] and other plasma lipids and apolipoproteins and target-organ damage (TOD) in patients with arteria[ hypertension. Design.-Cross-sectional study of a case series. Setting.-University medical center. Participants.-Lipoprotein(a) and apolipoproteins were analyzed in 277 untreated patients with mild to moderate essential hypertension and in 102 healthy controls. Apolipoprotein(a) [apo(a)] phenotypes were additionally analyzed in an independent sample set of 106 hypertensive and 105 control subjects. Main Outcome Measures.-Staging of TOD obtained according to World Health Organization guidelines by clinical evaluation, and laboratory tests including measurments of creatinine clearance, proteinuria, ophthalmoscopy, electrocardiography, echocardiography, and ultrasound examination of major arteries; levels of lipids, apolipoproteins, Lp(a), fibrinogen, and apo(a) phenotypes. Results.-Blood pressure, duration of hypertension, and levels of total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, Lp(a), and fibrinogen were significantly related to the presence and severity of TOD in univariate analysis. Stepwise multivariate analysis showed Lp(a) levels (P<.001) to be the best discriminator of the presence of TOD, followed by systolic blood pressure (P<.001), duration of hypertension (P=.01), and low-density lipoprotein cholesterol (P=.04). The Lp(a) levels were related to TOD independent of the level of blood pressure. We confirmed this association between Lp(a) concentrations and severity of TOD in a second independent sample set and observed a significantly higher frequency of low-molecular-weight apo(a) isoforms with increasing severity of TOD (P=.02). Conclusions.-Lipoprotein(a) and apo(a) phenotype are sensitive indicators of the severity of TOD in patients with essential hypertension, and their evaluation might permit identification of hypertensive subjects liable to the development of organ damage. The higher frequency of low-molecular-weight apo(a) isoforms in patients with TOD demonstrates a genetically determined risk for the development of TOD in hypertensive patients.