Lack of correlation between coronary risk factors and CAD severity

Interaction between a haptoglobin genetic variant and coronary artery disease (CAD) risk factors on CAD severity in Singaporean Chinese population

Background

Haptoglobin (Hp) is a plasma protein with strong anti‐inflammation and antioxidant activities. Its plasma level is known to be inversely associated with many inflammatory diseases, including cardiovascular diseases. However, the association of HP genetic variants with coronary artery disease (CAD) severity/mortality, and how they interact with common CAD risk factors are largely unknown.

Methods

We conducted the analysis in a Singaporean Chinese CAD population with Gensini severity scores (N = 582) and subsequently evaluated the significant findings in an independent cohort with cardiovascular mortality (excluding stroke) as outcome (917 cases and 19,093 controls). CAD risk factors were ascertained from questionnaires, and stenosis information from medical records. Mortality was identified through linkage with the nationwide registry of births and deaths in Singapore. Linear regression analysis between HP genetic variant (rs217181) and disease outcome were performed. Interaction analyses were performed by introducing an interaction term in the same regression models.

Results

Although rs217181 was not significantly associated with CAD severity and cardiovascular mortality (excluding stroke) in all subjects, when stratified by hypertension status, hypertensive individuals with the minor T allele have more severe CAD (β = 0.073, SE = 0.030, p = 0.015) and non‐hypertensive individuals with the T allele have lower risk for mortality (odds ratio = 0.771 (0.607–0.980), p = 0.033).

Conclusion

HP genetic variant is not associated with CAD severity and mortality in the general population. However, hypertensive individuals with the rs217181 T allele associated with higher Hp levels had more severe CAD while non‐hypertensive individuals with the same allele had lower risk for mortality in the Chinese population.

Lipoprotein(a): An underrecognized genetic risk factor for malignant coronary artery disease in young Indians

Malignant coronary artery disease (CAD) refers to a severe and extensive atherosclerotic process involving multiple coronary arteries in young individuals (aged <45 years in men and <50 years in women) with a low or no burden of established risk factors. Indians, in general, develop acute myocardial infarction (AMI) about 10 years earlier; AMI rates are threefold to fivefold higher in young Indians than in other populations. Although established CAD risk factors have a predictive value, they do not fully account for the excessive burden of CAD in young Indians. Lipoprotein(a) (Lp(a)) is increasingly recognized as the strongest known genetic risk factor for premature CAD, with high levels observed in Indians with malignant CAD. High Lp(a) levels confer a twofold to threefold risk of CAD-a risk similar to that of established risk factors, including diabetes. South Asians have the second highest Lp(a) levels and the highest risk of AMI from the elevated levels, more than double the risk observed in people of European descent. Approximately 25% of Indians and other South Asians have elevated Lp(a) levels (≥50 mg/dl), rendering Lp(a) a risk factor of great importance, similar to or surpassing diabetes. Lp(a) measurement is ready for clinical use and should be an essential part of all CAD research in Indians.

Relationship between Syntax Score and prognostic localization of coronary artery lesions with conventional risk factors, plasma profile markers, and carotid atherosclerosis (CAPP Study 2)

BACKGROUND

Data concerning the relationship between cardiovascular risk factors, plasmatic markers, carotid disease and extent of coronary lesions are lacking.

OBJECTIVES

To evaluate the role of cardiovascular risk factors, plasmatic levels of high sensitivity C-reactive protein (hs-CRP), fibrinogen, lipoprotein(a), and carotid plaque extension in predicting the severity of coronary artery disease (CAD).

METHODS

We analyzed 574 subjects undergoing first coronary angiography. For angiographic analysis, we used the Syntax Score and we defined the prognostic localization of CAD as a critical stenosis of the left main and/or proximal segment of left anterior descending artery. Levels of hs-CRP >3mg/L, lipoprotein(a) plasma levels >30mg/dL and plasma fibrinogen >300mg/dL were considered critical. Significant carotid disease (SCD) was defined by the presence of lesions producing a 50% diameter stenosis with a peak systolic velocity >125cm/s. A mean carotid intima media thickness (IMT) >0.9mm was considered abnormal.

RESULTS

In the adjusted analysis the presence of SCD was found to be an independent predictor of high Syntax Score (p<0.001), while high fibrinogen levels were independently associated with the presence of CAD in prognostic localization (p=0.04). In the sub-group of patients without SCD, IMT >0.9mm was found to be an independent predictor of the presence of CAD (p<0.001).

CONCLUSIONS

SCD strongly predicts high Syntax Score, while IMT shows excellent positive predictive value for the presence of CAD. In addition, high plasma fibrinogen levels are associated with coronary stenoses in prognostic localization.

Prevalence of conventional risk factors and lipid profiles in patients with acute coronary syndrome and significant coronary disease

BACKGROUND

Among patients with coronary artery disease (CAD), 80%-90% present at least one conventional risk factor. On the other hand, lipid profile modification after a cardiovascular event related to acute coronary syndrome (ACS) has been recognized. The prevalence of conventional risk factors and the lipid profile at the time of admission in patients with ACS and significant CAD (stenosis ≥50%) determined through coronary angiography is not well described.

METHODS

We studied 3,447 patients with a diagnosis of ACS and significant CAD with stenosis ≥50%, as shown o n angiography. We recorded the presence of conventional risk factors, including smoking, hypertension, dyslipidemia, and diabetes. In addition, we analyzed the lipid profiles within the first 24 hours of admission. We analyzed the studied population and compared findings according to sex.

RESULTS

Most patients (81.7%) were male. ST-elevation myocardial infarction was present in 51.3% of patients, and non-ST-elevation acute coronary syndrome was present in 48.7%. The most frequent risk factor was smoking, which was present in 68% of patients, followed by hypertension (57.8%), dyslipidemia (47.5%), and diabetes (37.7%). In women, the most frequent risk factors were hypertension, diabetes, and dyslipidemia, whereas in men, smoking was the most frequent. We identified at least one risk factor in 95.7% of all patients, two or three risk factors in 62%, and four risk factors in 8.6% of patients. The lipid profile analysis revealed that 85.1% of patients had some type of dyslipidemia, and the most frequent was low levels of high-density lipoprotein cholesterol (68.6% of cases).

CONCLUSION

We found at least one conventional risk factor in 95.7% of patients with ACS and significant CAD. The lipid profile analysis revealed that two thirds of cases had low high-density lipoprotein cholesterol levels.

Traditional cardiovascular risk factors and severity of angiographic coronary artery disease in the elderly

Over 80% of annual coronary heart disease mortality occurs in the elderly, a rapidly expanding subset of the population. The authors retrospectively examined the relationship between traditional cardiovascular risk factors and atherosclerotic coronary artery disease burden in a cohort of 631 elderly patients undergoing angiography. Age and male sex but not hypertension or dyslipidemia were predictors of presence of obstructive coronary artery disease (Duke score >or=2). Only diabetes mellitus emerged as an independent predictor of obstructive coronary artery disease burden. Smoking was found to be predictive of left main coronary artery disease. In summary, severity of angiographic disease in the elderly as assessed by Duke Myocardial Jeopardy scoring appears to correlate poorly with prevalence of established traditional cardiovascular risk factors.

Determining the relationship between metabolic syndrome score and angiographic severity of coronary artery disease

BACKGROUND

Cardiovascular disease is leading cause of mortality and morbidity in developed and developing countries. Metabolic syndrome (MS) is a risk factor for coronary artery disease (CAD). The effect of MS on angiographic severity of CAD is not well defined. The aim of this study was to examine the effect of MS on angiographic severity of CAD by using Gensini score.

METHODS

The total number of 1003 patients who underwent elective coronary angiography in catheter laboratory were included in the study. MS score based on National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) criteria which ranged between zero and five were calculated for each subject. Gensini scores were determined by examining coronary angiograms of the patients.

RESULTS

The study population consisted of 634 (63%) male, and 369 (37%) female subjects. The mean age was 59 +/- 11. MS based on NCEP ATP III was present in 246 (25%) patients. CAD was present in 691 patients (69%). The median of Gensini score was five (0-192) in the total sample, 18 (1-192) in the patients with CAD and 25 (0-192) in the patients with MS. A positive correlation was found between MS score and Gensini score (r = 0.402, p < 0.001).

CONCLUSIONS

In this study, it was determined that as the severity of MS increases, the angiographic severity of CAD increases as well. Besides, the most important factor on Gensini score was diabetes mellitus in male and hypertension in female subjects.

The relationship between the metabolic syndrome defined by various criteria and the extent of coronary artery disease

The association between the severity of coronary artery disease (CAD) and metabolic syndrome (MS) as defined by recently proposed criteria remains unknown. Therefore, we investigated the association between the severity of CAD and MS based on four sets of criteria. The frequency of MS and the severity of CAD determined using the Gensini score (GS) were assessed in 656 consecutive patients who underwent elective coronary angiography for the first time. Using the various criteria, 25.4% of males and 25.6% of females fulfilled the NCEP-ATPIII criteria, 46.6% of males and 21.3% of females fulfilled the International Diabetes Federation (IDF) criteria, 44.0% of males and 41.9% of females fulfilled the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) criteria, and 42.5% of males and 18.8% of females fulfilled the Japanese definition. On multivariate analysis, MS defined according to the AHA/NHLBI criteria was related to an increased risk of extensive CAD in males [odds ratio (OR) 1.89, p=0.001]. MS defined according to the IDF criteria was associated with the highest risk for extensive CAD in females (OR 2.83, p=0.019). In conclusion, MS was found to be associated with the extent of CAD. However, gender-specific differences and MS definition-specific differences exist.

A hypothesis out-of-date. the diet-heart idea

An almost endless number of observations and experiments have effectively falsified the hypothesis that dietary cholesterol and fats, and a high cholesterol level play a role in the causation of atherosclerosis and cardiovascular disease. The hypothesis is maintained because allegedly supportive, but insignificant findings, are inflated, and because most contradictory results are misinterpreted, misquoted or ignored.

Triglyceride expression

Current epidemiologic reports claim an important role for triglycerides in coronary artery disease (CAD). By cross-sectional data analysis, the role of triglycerides was assessed in 1726 consecutive patients investigated for chest pain, 1119 with CAD and 607 with normal coronaries. Besides study of male and female patients as separate groups, the males were divided into age groups of below 40 years, 41 to 50 years, 51 to 60 years and over 61 years. The female patients were divided into those below 50 years and over 51 years because of smaller numbers. Using the mean value for cholesterol, triglyceride, HDL cholesterol, LDL cholesterol and body mass index for normals as the demarcation line, logistic regression analysis was carried out to study their association in the patients with CAD and normals. Results showed that while the odds ratio for total cholesterol were higher for the younger age groups, the odds ratio for triglycerides were consistently higher for the groups over 51 years both male and female. It is speculated that there may be a difference in the relative importance of lipid fractions with reference to age in the development of atherosclerotic plaque with cholesterol playing a more important role in younger people and triglycerides being equally or more important in older people, on the basis of metabolic handling of lipid fractions.

A contemporary research paradigm for the genetic analysis of a common chronic disease

Rapid discoveries of novel and unexpected disease-associated genes for atherosclerotic coronary artery disease (CAD) are anticipated as genomic maps become more detailed and methods for mapping complex disease phenotypes become more refined. Although establishing association or linkage of a marker locus to a CAD susceptibility gene is an important first step, the long-term goal should be to define the underlying functional mutations and explore possible disease mechanisms, including the gene-environment interactions that culminate in clinically apparent disease. This review will define a contemporary research paradigm for study of the genetics of CAD and other common chronic diseases, using the tools of modern molecular biology and human genetics.

Genetic analysis of atherosclerosis: a research paradigm for the common chronic diseases

Rapid discoveries of novel and unexpected disease-associated genes for atherosclerotic coronary artery disease (CAD) are anticipated as genomic maps become more detailed and methods for mapping complex disease phenotypes become more refined. Although establishing association or linkage of a marker locus to a CAD susceptibility gene is an important first step, the long-term goal should be to define the underlying functional mutations and explore possible disease mechanisms, including the gene-environment interactions that culminate in clinically apparent disease. This review will define a contemporary research paradigm for study of the genetics of CAD and other common chronic diseases using the tools of modern molecular biology and human genetics.