Aortic Stenosis and Lipoprotein(a) - clinical studies.
Angiology. 2017 Jan 1:3319716688415. doi: 10.1177/0003319716688415. [Epub ahead of print]
Wilkinson MJ1, Ma GS1, Yeang C1, Ang L1, Strachan M1, DeMaria AN1, Tsimikas S1, Cotter B1.
Lipoprotein(a; Lp[a]) and its associated oxidized phospholipids are causal, genetic risk factors for calcific aortic valve stenosis (CAVS). We determined the prevalence of Lp(a) measurement among 2710 patients with CAVS and 1369 control patients (∼50% of study group) without CAVS with an echocardiogram between January 2010 and February 2016 in an academic echocardiography laboratory. Lipoprotein(a) measurements were performed at a referral laboratory using an isoform-independent assay. The prevalence of any Lp(a) measurement was 4.6% (124 of the 2710) in patients with CAVS and 3.1% (42 of the 1369) in the control group ( P = .021). In patients with CAVS, mean (standard deviation) Lp(a) levels were 38 (54) mg/dL and median (interquartile range) Lp(a) levels were 14 (6-48) mg/dL. Of the 124 patients with CAVS having Lp(a) measurements, 83 (66.9%) had Lp(a) <30 mg/dL and 41 (33.1%) had Lp(a) ≥30 mg/dL. This study reflects low physician testing of Lp(a) levels in CAVS. Given the role of Lp(a) as a causal risk factor for CAVS, and the ongoing development of therapies to normalize Lp(a) levels, our results suggest that Lp(a) measurements in CAVS should be more widely obtained in clinical practice.
Oxidized Phospholipids, Lipoprotein(a), and Progression of Calcific Aortic Valve Stenosis
J Am Coll Cardiol. 2015 Sep 15;66(11):1236-46. doi: 10.1016/j.jacc.2015.07.020
Capoulade R1, Chan KL2, Yeang C3, Mathieu P1, Bossé Y1, Dumesnil JG1, Tam JW4, Teo KK5, Mahmut A1, Yang X3, Witztum JL6, Arsenault BJ1, Després JP1, Pibarot P7, Tsimikas S8.
Elevated Lp(a) and OxPL-apoB levels are associated with faster AS progression and need for aortic valve replacement. These findings support the hypothesis that Lp(a) mediates AS progression through its associated OxPL and provide a rationale for randomized trials of Lp(a)-lowering and OxPL-apoB-lowering therapies in AS. (Aortic Stenosis Progression Observation: Measuring Effects of Rosuvastatin [ASTRONOMER]; NCT00800800).
Antisense therapy targeting apolipoprotein(a): a randomised, double-blind, placebo-controlled phase 1 study.
Lancet. 2015 Oct 10;386(10002):1472-83. doi: 10.1016/S0140-6736(15)61252-1. Epub 2015 Jul 22.
Tsimikas S1, Viney NJ2, Hughes SG2, Singleton W2, Graham MJ2, Baker BF2, Burkey JL2, Yang Q2, Marcovina SM3, Geary RS2, Crooke RM2, Witztum JL4.
ISIS-APO(a)Rx results in potent, dose-dependent, selective reductions of plasma Lp(a). The safety and tolerability support continued clinical development of ISIS-APO(a)Rx as a potential therapeutic drug to reduce the risk of cardiovascular disease and calcific aortic valve stenosis in patients with elevated Lp(a) concentration.
Genetic associations with valvular calcification and aortic stenosis.
N Engl J Med. 2013 Feb 7;368(6):503-12. doi: 10.1056/NEJMoa1109034.
Thanassoulis G1, Campbell CY, Owens DS, Smith JG, Smith AV, Peloso GM, Kerr KF, Pechlivanis S, Budoff MJ, Harris TB, Malhotra R, O'Brien KD, Kamstrup PR, Nordestgaard BG, Tybjaerg-Hansen A, Allison MA, Aspelund T, Criqui MH, Heckbert SR, Hwang SJ, Liu Y, Sjogren M, van der Pals J, Kälsch H, Mühleisen TW, Nöthen MM, Cupples LA, Caslake M, Di Angelantonio E, Danesh J, Rotter JI, Sigurdsson S, Wong Q, Erbel R, Kathiresan S, Melander O, Gudnason V, O'Donnell CJ, Post WS; CHARGE Extracoronary Calcium Working Group.
One SNP in the lipoprotein(a) (LPA) locus (rs10455872) reached genomewide significance for the presence of aortic-valve calcification (odds ratio per allele, 2.05; P=9.0×10(-10)), a finding that was replicated in additional white European, African-American, and Hispanic-American cohorts (P<0.05 for all comparisons). Genetically determined Lp(a) levels, as predicted by LPA genotype, were also associated with aortic-valve calcification, supporting a causal role for Lp(a). In prospective analyses, LPA genotype was associated with incident aortic stenosis (hazard ratio per allele, 1.68; 95% confidence interval [CI], 1.32 to 2.15) and aortic-valve replacement (hazard ratio, 1.54; 95% CI, 1.05 to 2.27) in a large Swedish cohort; the association with incident aortic stenosis was also replicated in an independent Danish cohort. Two SNPs (rs17659543 and rs13415097) near the proinflammatory gene IL1F9 achieved genomewide significance for mitral annular calcification (P=1.5×10(-8) and P=1.8×10(-8), respectively), but the findings were not replicated consistently.
Genetic variation in the LPA locus, mediated by Lp(a) levels, is associated with aortic-valve calcification across multiple ethnic groups and with incident clinical aortic stenosis. (Funded by the National Heart, Lung, and Blood Institute and others.).
Elevated lipoprotein(a) and risk of aortic valve stenosis in the general population.
J Am Coll Cardiol. 2014 Feb 11;63(5):470-7. doi: 10.1016/j.jacc.2013.09.038. Epub 2013 Oct 23.
Kamstrup PR1, Tybjærg-Hansen A2, Nordestgaard BG3.
Elevated Lp(a) levels were associated with multivariable adjusted hazard ratios for AVS of 1.2 (95% confidence interval [CI]: 0.8 to 1.7) for 22nd to 66th percentile levels (5 to 19 mg/dl), 1.6 (95% CI: 1.1 to 2.4) for 67th to 89th percentile levels (20 to 64 mg/dl), 2.0 (95% CI: 1.2 to 3.4) for 90th to 95th percentile levels (65 to 90 mg/dl), and 2.9 (95% CI: 1.8 to 4.9) for levels greater than 95th percentile (>90 mg/dl), versus levels less than the 22nd percentile (<5 mg/dl; trend, p < 0.001). Lp(a) levels were elevated among carriers of rs10455872 and rs3798220 minor alleles, and of low number of KIV-2 repeats (trend, all p < 0.001). Combining all genotypes, instrumental variable analysis yielded a genetic relative risk for AVS of 1.6 (95% CI: 1.2 to 2.1) for a 10-fold Lp(a) increase, comparable to the observational hazard ratio of 1.4 (95% CI: 1.2 to 1.7) for a 10-fold increase in Lp(a) plasma levels.
Elevated Lp(a) levels and corresponding genotypes were associated with increased risk of AVS in the general population, with levels >90 mg/dl predicting a threefold increased risk.
Aortic valve calcification in systemic lupus erythematosus.
Kiani AN1, Fishman EK, Petri M..
Aortic valve calcification is associated with atherosclerosis in the general population. We investigated the prevalence of and associates of aortic valve calcification in systemic lupus erythematosus (SLE). One-hundred and ninety-nine SLE patients enrolled in a clinical trial had aortic valve calcification assessed by helical CT. The patients had a mean age of 44.3 +/- 11.4 years and were 92% female, 61% Caucasian, 34% African-American, 2% Asian and 2% Hispanic. Aortic valve calcification was present in 1.5%, whereas coronary calcium was found in 43% and carotid plaque in 17%. Among cardiovascular risk factors, hs-CRP (P = 0.0592), fibrinogen (P = 0.0507), and lipoprotein(a) (P = 0.0250), were associated with aortic valve calcification. Prednisone use (P = 0.049) and use of methotrexate (P = 0.0174) were also associated with aortic valve calcification. Aortic valve calcification was associated with antiphospholipid antibody positivity (0.0287) (lupus anticoagulant, by dilute Russell viper venom time). It was not associated with coronary calcium or carotid plaque. Aortic valve calcification, although rare in SLE, was associated with some novel cardiovascular risk factors and with a marker of hypercoagulability (lupus anticoagulant). In contrast to the general population, aortic valve calcification in SLE is not associated with subclinical measures of atherosclerosis, such as coronary calcium or carotid plaque.