The effect of statin therapy on Lipoprotein(a)
Evidence that elevated lipoprotein(a) (Lp[a]) levels contribute to cardiovascular disease (CVD) and calcific aortic valve stenosis (CAVS) is substantial. Development of isoform-independent assays, in concert with genetic, epidemiological, translational, and pathophysiological insights, have established Lp(a) as an independent, genetic, and likely causal risk factor for CVD and CAVS. These observations are consistent across a broad spectrum of patients, risk factors, and concomitant therapies, including patients with low-density lipoprotein cholesterol <70 mg/dl. Statins tend to increase Lp(a) levels, possibly contributing to the "residual risk" noted in outcomes trials and at the bedside. Recently approved proprotein convertase subtilisin/kexin-type 9 inhibitors and mipomersen lower Lp(a) 20% to 30%, and emerging RNA-targeted therapies lower Lp(a) >80%. These approaches will allow testing of the "Lp(a) hypothesis" in clinical trials. This review summarizes the current landscape of Lp(a), discusses controversies, and reviews emerging therapies to reduce plasma Lp(a) levels to decrease risk of CVD and CAVS.
Oxidized phospholipids (OxPL) on apolipoprotein B-100 (OxPL-apoB) reflect the biological activity of lipoprotein(a) (Lp[a]) and predict cardiovascular disease events. However, studies with statins and low-fat diets show increases in OxPL-apoB and Lp(a).
This study evaluated changes in OxPL-apoB and Lp(a) with extended-release niacin (N), ezetimibe/simvastatin (E/S) and combination E/S/N. A systematic literature review of previously published trials, measuring both OxPL-apoB and Lp(a) after therapeutic interventions, was also performed.
OxPL-apoB and Lp(a) were measured in 591 patients at baseline and 24 weeks after therapy with N, E/S, or E/S/N in a previously completed randomized trial of hypercholesterolemic patients. The literature review included 12 trials and 3896 patients evaluating statins, low-fat diets, antisense to apolipoprotein(a) and lipid apheresis.
Niacin decreased OxPL-apoB levels (median [interquartile range]; 3.5 [2.2-9.2] nM to 3.1 [1.8-7.2] nM, P < .01) and Lp(a) (10.9 [4.6-38.4] to 9.3 [3.1-32.9] mg/dL, P < .01). In contrast, E/S and E/S/N significantly increased OxPL-apoB (3.5 [2.1-7.8] to 4.9 [3.0-11.1] nM, P < .01) and (3.3 [1.9-9.3] to 4.3 [2.6-11.2] nM, P < .01), respectively and Lp(a) (11.5 [6.1-36.4] to 14.9 [6.6-54.6] mg/dL, P < .01) and (11.3 [5.4-43.8] to 11.6 [5.9-52.8] mg/dL, P < .01), respectively. The systematic review of statins and diet demonstrated 23.8% and 21.3% mean increases in OxPL-apoB and 10.6% and 19.4% increases in Lp(a), respectively. However 44.1% and 52.0% decreases in OxPL-apoB and Lp(a), respectively, were present with Lp(a)-lowering therapies.
This study demonstrates differential changes in OxPL-apoB and Lp(a) with various lipid-lowering approaches. These changes in OxPL-apoB and Lp(a) may provide insights into the results and interpretation of recent cardiovascular disease outcomes trials.