High level of lipoprotein(a) is a strong predictor for progression of coronary artery disease

Predictive value of lipoprotein(a) for assessing the prevalence and severity of lower-extremity peripheral artery disease among patients with acute coronary syndrome

Lipoprotein(a) [Lp(a)] is a reliable lipid marker for atherosclerosis. However, the clinical relevance of Lp(a) to lower-extremity peripheral artery disease (LE-PAD) and coronary artery disease (CAD) in the same patient has not been investigated. Patients who received primary percutaneous coronary intervention for the acute coronary syndrome (ACS) were enrolled. Patients who received hemodialysis, required multidisciplinary treatments, or had incomplete medical history were excluded. A total of 175 patients were divided into two groups according to whether they had LE-PAD (n = 21) or did not (n = 154), and three multivariable logistic regression models were used to assess if Lp(a) level is associated with LE-PAD prevalence. In addition, serum Lp(a) levels were compared among three groups according to the severity of LE-PAD (none, unilateral, or bilateral) and CAD. Serum Lp(a) levels were significantly higher in patients with LE-PAD than in those without (31.0 mg/dL vs. 13.5 mg/dL, p = 0.002). After adjusting for confounding factors, higher Lp(a) levels were independently associated with the prevalence of LE-PAD in all three models (p < 0.001 for all). With respect to LE-PAD severity, serum Lp(a) levels were significantly higher in the bilateral LE-PAD groups than in the group with no LE-PAD (p = 0.005 for all), whereas Lp(a) was not associated with CAD severity. Though Lp(a) levels are associated with the prevalence and severity of LE-PAD, are not associated with the severity of CAD among patients with ACS.

Lipoprotein(a): An independent, genetic, and causal factor for cardiovascular disease and acute myocardial infarction

Lipoprotein(a) [Lp(a)] is a circulating lipoprotein, and its level is largely determined by variation in the Lp(a) gene (LPA) locus encoding apo(a). Genetic variation in the LPA gene that increases Lp(a) level also increases coronary artery disease (CAD) risk, suggesting that Lp(a) is a causal factor for CAD risk. Lp(a) is the preferential lipoprotein carrier for oxidized phospholipids (OxPL), a proatherogenic and proinflammatory biomarker. Lp(a) adversely affects endothelial function, inflammation, oxidative stress, fibrinolysis, and plaque stability, leading to accelerated atherothrombosis and premature CAD. The INTER-HEART Study has established the usefulness of Lp(a) in assessing the risk of acute myocardial infarction in ethnically diverse populations with South Asians having the highest risk and population attributable risk. The 2018 Cholesterol Clinical Practice Guideline have recognized elevated Lp(a) as an atherosclerotic cardiovascular disease risk enhancer for initiating or intensifying statin therapy.

Prediction of Short-Term Progression or Regression of Atherosclerotic Coronary Artery Disease by Lipoprotein (a): A Quantitative Coronary Angiographic Study

This study assessed whether progression of coronary artery atherosclerotic lesions could be predicted in the short term using various lipid profiles. In 37 patients (61.9 ±9.5 years) under going coronary angioplasty and with 6-month follow-up angiography, quantitative coronary angiography of a new or changed lesion was performed in the follow-up examination, except for intervention vessels. The progression-regression score of the assessed lesion was calcu lated as the baseline minus the follow-up minimal lumen diameter. The serum lipoprotein (a) level was higher in the progression group (progression-regression score >0.15 mm), than in the regression group (≤ -0.15 mm; p<0.01) and the no change group (within ±0.15 mm; p < 0.05). Remnant-like lipoprotein particle-cholesterol and apolipoprotein-B levels were also higher in the progression group. However, multiple regression analysis of the progression showed that the progression-regression score was independently correlated with lipoprotein (a) alone (R = 0.50, p < 0.05). This shows that lipoprotein (a) is an independent predictor of coronary atherosclerotic lesion progression over the short term.

Impact of lipoprotein(a) as residual risk on long-term outcomes in patients after percutaneous coronary intervention

Cardiovascular risk remains uncertain in patients with cardiovascular disease despite achieving target lipid levels. Serum levels of lipoprotein(a) [Lp(a)] can be risk factors for adverse events. The aim of this study was to determine the role of Lp(a) as a residual risk factor in patients who achieve target lipid levels by the time of treatment by percutaneous coronary intervention (PCI). A total of 3,508 patients were treated by PCI from 1997 to 2011 at our institution. Among them, we analyzed consecutive 569 patients who achieved target lipid levels of low-density lipoprotein cholesterol <100 mg/dl, high-density lipoprotein cholesterol ≥40 mg/dl, and triglycerides <150 mg/dl at PCI. A total of 411 eligible patients were assigned to groups according to Lp(a) levels of ≥30 mg/dl (high Lp(a); n = 119) or <30 mg/dl (low Lp(a); n = 292). The primary outcome was a composite of all-cause death and acute coronary syndrome. The median follow-up period was 4.7 years. Cumulative event-free survival was significantly worse for the group with high Lp(a) than with low Lp(a) group (p = 0.04). Multivariate analysis selected a high Lp(a) level as an independent predictor of primary outcomes (hazard ratio 1.68, 95% confidence interval 1.03 to 2.70, p = 0.04). In conclusion, a high Lp(a) value (≥30 mg/dl) could be associated with a poor prognosis after PCI even for patients who achieved target lipid levels.

Lipoprotein (A): Better assessor of coronary heart disease risk in south Indian population

In an attempt to search for risk factors which can explain the increasing prevalence of coronary heart disease (CHD) in Indian population, we conducted a case-control study to assess the association of Lipoprotein (a)(Lp(a)) with CHD. One hundred and fifty one consecutive patients with clinical and angiographic evidence of CHD and forty-nine healthy controls were drawn for the study. Triglycerides, very low density cholesterol (VLDL-C), total cholesterol (total-C)/high density cholesterol (HDL-C) ratio, low density cholesterol (LDL-C)/HDL cholesterol ratio and Lp(a) were found to be higher in patients than controls. In female sex and in those with family history of CHD, higher total and LDL cholesterol levels were observed to be associated with higher Lp(a) levels. Lp(a) levels were also found to be higher in triple vessel disease than other vessel disease patients. Significant difference in Lp(a) levels were observed between normal coronaries vs. single and triple vessel disease(P<0.05) and also between single vs. double and triple vessel disease (P<0.01).Lp(a) levels correlated positively with vessel severity(P<0.005). Lp(a) levels >25 mg/dl were associated with coronary heart disease (Odds ratio 1.98 P<0.05 95% CI 0.007-1.18). Our findings suggest a cut-off level of 25mg/dl for determination of risk of CHD. Studies from different areas involving larger sample size are needed to confirm the findings of the present study.

Relation between lipoprotein(a) and fibrinogen and serial intravascular ultrasound plaque progression in left main coronary arteries

OBJECTIVES

Patients with elevated lipoprotein(a) [Lp(a)] and fibrinogen levels have an increased risk of coronary heart disease and adverse cardiovascular events. There is evidence that coronary plaque progression is linked to a higher risk for future cardiovascular events.

BACKGROUND

There are no data demonstrating a relation between Lp(a), fibrinogen, and directly measured coronary plaque progression over time.

METHODS

We performed a retrospective analysis of serial intravascular ultrasound (IVUS) studies of 60 left main stems (18 +/- 9 months apart) to evaluate plaque progression in relation to Lp(a) and fibrinogen levels and association with adverse cardiovascular events.

RESULTS

There was a positive correlation between Lp(a) (r = 0.58; p < 0.0001), fibrinogen (r = 0.48; p < 0.0001), and changes in plaque-plus-media area. Patients with plaque progression (n = 41) had higher Lp(a) (30 +/- 26 mg/dl vs. 14 +/- 9 mg/dl; p < 0.0012) and fibrinogen (295 +/- 88 mg/dl vs. 240 +/- 72 mg/dl; p = 0.019) levels than patients with plaque regression (n = 19). Multivariate linear regression analysis showed Log Lp(a) (regression coefficient = 9.45; p = 0.0008) but not fibrinogen to be independently associated with plaque progression. A total of 19 patients suffered from adverse cardiovascular events; they had higher Lp(a) (44 +/- 30 mg/dl vs. 16 +/- 12 mg/dl; p < 0.0001) and fibrinogen (342 +/- 73 mg/dl vs. 248 +/- 76 mg/dl; p < 0.0001) levels. Multivariate logistic regression analysis showed Log Lp(a) (odds ratio 10.20, 95% confidence interval 2.36 to 44.13; p = 0.0019) and fibrinogen (odds ratio 1.01, 95% confidence interval 1.00 to 1.03; p = 0.018) were independently associated with adverse cardiovascular events.

CONCLUSIONS

Serial IVUS showed a positive correlation between Lp(a) and fibrinogen levels and plaque progression. Lp(a), but not fibrinogen, remains independently associated with plaque progression. In addition, the present data suggest a considerable incremental value of Lp(a) in predicting cardiovascular risk.

Risk factors for progression of peripheral arterial disease in large and small vessels

BACKGROUND

Data on the natural history of peripheral arterial disease (PAD) are scarce and are focused primarily on clinical symptoms. Using noninvasive tests, we assessed the role of traditional and novel risk factors on PAD progression. We hypothesized that the risk factors for large-vessel PAD (LV-PAD) progression might differ from small-vessel PAD (SV-PAD).

METHODS AND RESULTS

Between 1990 and 1994, patients seen during the prior 10 years in our vascular laboratories were invited for a new vascular examination. The first assessment provided baseline data, with follow-up data obtained at this study. The highest decile of decline was considered major progression, which was a -0.30 ankle brachial index decrease for LV-PAD and a -0.27 toe brachial index decrease for SV-PAD progression. In addition to traditional risk factors, the roles of high-sensitivity C-reactive protein, serum amyloid-A, lipoprotein(a), and homocysteine were assessed. Over the average follow-up interval of 4.6+/-2.5 years, the 403 patients showed a significant ankle brachial index and toe brachial index deterioration. In multivariable analysis, current smoking, ratio of total to HDL cholesterol, lipoprotein(a), and high-sensitivity C-reactive protein were related to LV-PAD progression, whereas only diabetes was associated with SV-PAD progression.

CONCLUSIONS

Risk factors contribute differentially to the progression of LV-PAD and SV-PAD. Cigarette smoking, lipids, and inflammation contribute to LV-PAD progression, whereas diabetes was the only significant predictor of SV-PAD progression.

Genes and atherosclerosis: at the origin of the predisposition

Atherosclerosis (ATS) is a multifactorial disease caused by the interaction of established or emerging risk factors with multiple predisposing genes that regulate ATS-related processes. This review will discuss the current knowledge concerning the potential role of the genetic variations that could promote and/or accelerate ATS, in both animal models and humans. Allelic polymorphisms or variations of distinct genes that enhance the risk of ATS frequently occur in the general population, but only adequate gene-environment interactions will lead to the disease. The main genes so far studied are involved in the regulation of processes such as endothelial function, antioxidant potential, coagulation, inflammatory response, and lipid, protein and carbohydrate metabolism. The detection of candidate genes associated with ATS could allow, in the near future, earlier interventions in genetically susceptible individuals. Further, large-scale population studies are needed to obtain more information on the specific gene-environment and drug-gene interactions capable of influencing ATS progression.

Lipoprotein(a): an emerging cardiovascular risk factor

Lipoprotein(a) is a cholesterol-enriched lipoprotein, consisting of a covalent linkage joining the unique and highly polymorphic apolipoprotein(a) to apolipoprotein B100, the main protein moiety of low-density lipoproteins. Although the concentration of lipoprotein(a) in humans is mostly genetically determined, acquired disorders might influence synthesis and catabolism of the particle. Raised concentration of lipoprotein(a) has been acknowledged as a leading inherited risk factor for both premature and advanced atherosclerosis at different vascular sites. The strong structural homologies with plasminogen and low-density lipoproteins suggest that lipoprotein(a) might represent the ideal bridge between the fields of atherosclerosis and thrombosis in the pathogenesis of vascular occlusive disorders. Unfortunately, the exact mechanisms by which lipoprotein(a) promotes, accelerates, and complicates atherosclerosis are only partially understood. In some clinical settings, such as in patients at exceptionally low risk for cardiovascular disease, the potential regenerative and antineoplastic properties of lipoprotein(a) might paradoxically counterbalance its athero-thrombogenicity, as attested by the compatibility between raised plasma lipoprotein(a) levels and longevity.

Molecular genetics and gene expression in atherosclerosis

Although molecular cardiology is a relative young discipline, the impact of the new techniques on diagnosis and therapy in cardiovascular disease are extensive. Our insight into pathophysiological mechanisms is rapidly expanding and is changing our understanding of cardiovascular disease radically and irrevocably. Molecular cardiology has many different aspects. In this paper the importance of molecular cardiology and genetics for every day clinical practice are briefly outlined. It is expected that in the genetic predisposition for atherosclerotic disease multiple genes are involved (genetics). The role of only a minority of genes involved in the atherosclerotic process is known. Far less is known about particular gene-gene and gene-environment interactions. In some families disease can be explained mostly by a single, major gene (monogenic), of which the lipid disorder Familial Hypercholesterolemia is an example. In other cases, one or several variations in minor genes (multigenic) contribute to an atherosclerotic predisposition, for instance the lipoprotein lipase gene. Although mutations in this gene influence lipoprotein levels, disease development is predominantly depending on environmental influences. Recently several additional genetic risk factors were identified including elevated levels of lipoprotein (a) [Lp(a)], the DD genotype of angiotensin converting enzyme (ACE), and elevated levels of homocysteine. This illustrates the complexity of genetics in relation to atherosclerosis and the difficulty to assign predictive values to separate genetic risk factors. Furthermore, little attention has been given to protective genes thus far, explaining why some high risk patients are protected from vascular disease. Genetics based treatment or elimination of the genetic risk factor requires complete understanding of the pathogenic molecular basis. Once this requirement is fulfilled, disease management can be strived for, provided that adequate medical management is available. Recent studies suggest that such treatment should be genotype specific, as the genetic makeup can determine the outcome of a pharmacological intervention (pharmacogenetics). Once the trigger for atherosclerosis has initiated disease development, various genes are activated or silenced and contribute to lesion progression. Every stage of lesion development depends on a different gene expression programme (genomics). In this review paper an introduction is provided into genetics, pharmacogenetics and gene expression with respect to atherosclerotic disease.