The therapeutic management of South African dyslipidaemic patients at very high cardiovascular risk (CARDIO TRACK): a cross-sectional study

BACKGROUND

Dyslipidaemia is a major modifiable risk factor for atherosclerotic cardiovascular disease. At the time the study was conducted, guidelines recommended a low-density lipoprotein cholesterol (LDL-C) target of less than 1.8 mmol/l and a reduction of at least 50% if the baseline LDL-C was between 1.8 and 3.5 mmol/l in patients with either very high cardiovascular risk or established atherosclerosis. In South Africa, there is a paucity of data on attainment of LDL-C goal in patients with very high cardiovascular risk who are on maximum tolerated statin with or without ezetimibe.

OBJECTIVE

The aim was to assess the percentage of very high cardiovascular risk South African patients with dyslipidaemia not reaching an LDL-C goal of less than 1.8 mmol/l, despite maximum tolerated statin with or without ezetimibe.

METHODS

This was a multi-centre, observational, cross-sectional study conducted at 15 private healthcare sector sites and one public sector site. Adults (> 18 years) with very high cardiovascular risk of familial hypercholesterolaemia receiving stable, maximum-tolerated statin therapy for at least four weeks prior to their latest lipid profile were enrolled into the study, and electronic case report forms were completed after written informed consent was provided. LDL-C goal attainment was modelled, first assuming an increase in the statin dose to the registered maximum, followed by the addition of ezetimibe or a PCSK9-inhibitor.

RESULTS

In total, 507 patients were screened, of whom 492 were eligible for study participation. One patient was excluded from the analysis because of a missing LDL-C value. Most participants were male (male 329, 67%; female 162, 33%). Most patients were either obese (223, 46.0%) or overweight (176, 36.3%). Hypertension and diabetes mellitus were frequent co-morbidities and were found in 381 (77.6%) and 316 (64.4%) patients, respectively. Eighty (16.3%) patients reported current smoking. Only 68 (13.8%) patients were taking ezetimibe in addition to a statin. Reasons for not using ezetimibe included no requirement for ezetimibe in the opinion of the treating physician (229, 48.7%), cost (149, 31.7%), Physician's choice (39, 8.3%), or other (53, 11.3%). Only 161 (32.8%) of the patients attained their goal LDL-C level. In our modelling analysis, increasing the statin dose to the registered maximum and adding ezetimibe brought an additional 34.5% of patients to goal, while adding a PCSK9-inhibitor, irrespective of any other changes to lipid-lowering therapy brought over 90% of not-at-goal patients to goal.

CONCLUSIONS

Most study participants were not at LDL-C goal despite maximum-tolerated statin, highlighting the need for treatment intensification in this high-risk population. Although intensifying treatment by adding a PCSK9-inhibitor brought more patients to goal, the initial addition of ezetimibe would be more reasonable, given the cost of PCSK9-inhibitors.

2020 Heart Failure Society of South Africa perspective on the 2016 European Society of Cardiology Chronic Heart Failure Guidelines

Heart failure with a reduced ejection fraction (HFrEF) is a condition frequently encountered by healthcare professionals and, in order to achieve the best outcomes for patients, needs to be managed optimally. This guideline document is based on the European Society of Cardiology Guidelines for the treatment of acute and chronic heart failure published in 2016, and summarises what is considered the best current management of patients with the condition. It provides information on the definition, diagnosis and epidemiology of HFrEF in the African context. The best evidence-based treatments for HFrEF are discussed, including established therapies (beta-blockers, ACE-i/ARBs, mineralocorticoid receptor antagonists (MRAs), diuretics) that form the cornerstone of heart failure management as well as therapies that have only recently entered clinical use (angiotensin receptor-neprilysin inhibitor (ARNI), sodium/glucose cotransporter-2 (SGLT2) inhibitors). Guidance is offered in terms of more invasive therapies (revascularisation, implantable cardioverter defibrillators (ICDs) and cardiac resynchronisation therapy (CRT) by implantation of a biventricular pacemaker with (CRT-D) or without (CRT-P) an ICD, left ventricular assist device (LVAD) use and heart transplantation) in order to ensure efficient use of these expensive treatment modalities in a resource-limited environment. Furthermore, additional therapies (digoxin, hydralazine and nitrates, ivabradine, iron supplementation) are discussed and advice is provided on general preventive strategies (vaccinations). Sections to discuss conditions that are particularly prevalent in sub-Saharan Africa (HIV-associated cardiomyopathy (CMO), peripartum CMO, rheumatic heart disease, atrial fibrillation) have been added to further improve clinical care for these commonly encountered disease processes. You are encouraged to read the complete 2016 ESC Heart Failure guideline: Ponikowski P, Voors AA, Anker SD, et al.; on behalf of the European Society of Cardiology. 2016 ESC guidelines for the diagnosis and treatment of acute and chronic heart failure. Eur Heart J 2016,37:2129-2200.

PCSK9 Inhibitors: From Nature’s Lessons to Clinical Utility

Background:

Proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors are a novel class of non-statin lipid lowering therapy that reduce LDL-cholesterol by 50 - 60%. PCSK9 inhibitors decrease LDL-cholesterol by preventing intracellular degradation of LDL receptors; subsequently, a greater number of LDL-receptors are available on the cell surface to extract circulating LDL.

Objective:

To describe the origins of PCSK9 inhibitors and their current use in clinical practice.

Methods:

We performed a narrative review of the PCSK9 inhibitor class of drugs.

Results:

Current data indicate that PCSK9 inhibitors effectively reduce LDL-cholesterol and are well tolerated and safe. PCSK9 inhibitors have also been shown to reduce cardiovascular event rates in patients with stable atherosclerotic cardiovascular disease and in patients with a recent (up to one year) acute coronary syndrome. Given the costs, chronicity of the treatment and the potential budget impact, PCSK9 inhibitors are often limited to patients with the highest absolute risk for major adverse cardiovascular events despite optimal treatment with high-intensity statin and ezetimibe.

Conclusion:

PCSK9 inhibitors have a favorable safety, efficacy and tolerability profile. Postmarketing safety surveillance and real-world studies are needed to further support the long-term safety profile of this class of medicine.

A Narrative Review and Expert Panel Recommendations on Dyslipidaemia Management After Acute Coronary Syndrome in Countries Outside Western Europe and North America

Patients who have experienced an acute coronary syndrome (ACS) are at very high risk of recurrent atherosclerotic cardiovascular disease (CVD) events. Dyslipidaemia, a major risk factor for CVD, is poorly controlled post ACS in countries outside Western Europe and North America, despite the availability of effective lipid-modifying therapies (LMTs) and guidelines governing their use. Recent guideline updates recommend that low-density lipoprotein cholesterol (LDL-C), the primary target for dyslipidaemia therapy, be reduced by ≥ 50% and to < 1.4 mmol/L (55 mg/dL) in patients at very high risk of CVD, including those with ACS. The high prevalence of CVD risk factors in some regions outside Western Europe and North America confers a higher risk of CVD on patients in these countries. ACS onset is often earlier in these patients, and they may be more challenging to treat. Other barriers to effective dyslipidaemia control include low awareness of the value of intensive lipid lowering in patients with ACS, physician non-adherence to guideline recommendations, and lack of efficacy of currently used LMTs. Lack of appropriate pathways to guide follow-up of patients with ACS post discharge and poor access to intensive medications are important factors limiting dyslipidaemia therapy in many countries. Opportunities exist to improve attainment of LDL-C targets by the use of country-specific treatment algorithms to promote adherence to guideline recommendations, medical education and greater prioritisation by healthcare systems of dyslipidaemia management in very high risk patients.

Marfan syndrome: a case report and pictorial essay

We report a case of Marfan syndrome (MFS) in a South African patient, which is extraordinary because of the large constellation of clinical, radiological and vascular anomalies in a single patient. A literature search from 1950 to date did not show a similar report of such extensive clinical characteristics of MFS.

Obesity-associated genetic variants in young Asian Indians with the metabolic syndrome and myocardial infarction

OBJECTIVE

Associations between obesity-related polymorphisms and the metabolic syndrome in 485 young ( ≤ 45 Years) Asian Indian patients with acute myocardial infarction (AMI), and 300 matched controls were assessed.

METHODS

Genetic variants included the adiponectin 45T→G and 276G→T, LEPR K109R and Q223R, MC4R-associated C→T and FTO A→T polymorphisms.

RESULTS

The metabolic syndrome, as defined by NCEP ATP III and IDF criteria, was diagnosed in 61 and 60% of patients, respectively. No relationship was found between the obesity-associated polymorphisms and the metabolic syndrome, or between AMI patients and controls. The MC4R-associated TT genotype occurred more frequently in patients with lower triglyceride levels (p = 0.024), while the adiponectin 45 TT genotype occurred more commonly in patients with normal fasting glucose levels (p = 0.004). The LEPR Q223R TT genotype was associated with low high-density lipoprotein (HDL) cholesterol levels (p = 0.003).

CONCLUSION

The metabolic syndrome occurs commonly in young Asian Indian patients with AMI. No relationship was found between any obesity-associated polymorphism and the metabolic syndrome. Particular genotypes may exert protective or disadvantageous effects on individual components of the metabolic syndrome.

Effects of statin therapy according to plasma high-sensitivity C-reactive protein concentration in the Controlled Rosuvastatin Multinational Trial in Heart Failure (CORONA): a retrospective analysis

BACKGROUND

We examined whether the antiinflammatory action of statins may be of benefit in heart failure, a state characterized by inflammation in which low cholesterol is associated with worse outcomes.

METHODS AND RESULTS

We compared 10 mg rosuvastatin daily with placebo in patients with ischemic systolic heart failure according to baseline high sensitivity-C reactive protein (hs-CRP) <2.0 mg/L (placebo, n=779; rosuvastatin, n=777) or > or = 2.0 mg/L (placebo, n=1694; rosuvastatin, n=1711). The primary outcome was cardiovascular death, myocardial infarction, or stroke. Baseline low-density lipoprotein was the same, and rosuvastatin reduced low-density lipoprotein by 47% in both hs-CRP groups. Median hs-CRP was 1.10 mg/L in the lower and 5.60 mg/L in the higher hs-CRP group, with higher hs-CRP associated with worse outcomes. The change in hs-CRP with rosuvastatin from baseline to 3 months was -6% in the low hs-CRP group (27% with placebo) and -33.3% in the high hs-CRP group (-11.1% with placebo). In the high hs-CRP group, 548 placebo-treated (14.0 per 100 patient-years of follow-up) and 498 rosuvastatin-treated (12.2 per 100 patient-years of follow-up) patients had a primary end point (hazard ratio of placebo to rosuvastatin, 0.87; 95% confidence interval, 0.77 to 0.98; P=0.024). In the low hs-CRP group, 175 placebo-treated (8.9 per 100 patient-years of follow-up) and 188 rosuvastatin-treated (9.8 per 100 patient-years of follow-up) patients experienced this outcome (hazard ratio, 1.09; 95% confidence interval, 0.89 to 1.34; P>0.2; P for interaction=0.062). The numbers of deaths were as follows: 581 placebo-treated (14.1 per 100 patient-years of follow-up) and 532 rosuvastatin-treated (12.6 per 100 patient-years) patients in the high hs-CRP group (hazard ratio, 0.89; 95% confidence interval, 0.79 to 1.00; P=0.050) and 170 placebo-treated (8.3 per 100 patient-years) and 192 rosuvastatin-treated (9.7 per 100 patient-years) patients in the low hs-CRP group (hazard ratio, 1.17; 95% confidence interval, 0.95 to 1.43; P=0.14; P for interaction=0.026).

CONCLUSIONS

In this retrospective hypothesis-generating study, we found a significant interaction between hs-CRP and the effect of rosuvastatin for most end points whereby rosuvastatin treatment was associated with better outcomes in patients with hs-CRP > or = 2.0 mg/L.

CLINICAL TRIAL REGISTRATION INFORMATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00206310.

Genetic variants associated with insulin resistance and metabolic syndrome in young Asian Indians with myocardial infarction

BACKGROUND

The objective of this study was to assess whether an association exists between the metabolic syndrome and polymorphisms in genes involved in insulin resistance in young Asian Indian patients presenting with acute myocardial infarction (AMI).

METHODS

The study population comprised 467 patients who were 45 years or younger. The National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) and the International Diabetes Federation (IDF) definitions were used to assess the prevalence of metabolic syndrome. We examined the genotype and allele frequencies of the IRS-I G972R, PPAR-gamma P12A, KCNJ11 E23K, and TNF-alpha -308G/A polymorphisms in relation to the metabolic syndrome determined by both definitions.

RESULTS

The metabolic syndrome as defined by the NCEP ATP III criteria was found in 282 (60.4%) patients, and in 278 (59.5%) patients according to the IDF criteria. This gave only a moderate level of agreement of 79% between the two definitions (Cohen's kappa = 0.554). No association was found between the IRS-I G972R, PPAR-gamma P12A, and KCNJ11 E23K, or TNF-alpha -308G/A polymorphic variants and the metabolic syndrome, or its components, for either definition.

CONCLUSION

Although the metabolic syndrome is a common finding in young Asian Indian patients with AMI, there was only a moderate level of agreement between the NCEP ATP III and IDF definitions of the syndrome. Our findings do not support a role for any of the polymorphic variant alleles in the four insulin resistance-related genes examined in the etiology of insulin resistance and reinforces the notion of a multifactorial etiology for the metabolic syndrome.

The role of echocardiography and its comparison with NT-proBNP measurements in patients with acute myocardial infarction

BACKGROUND

This study investigated the use of echocardiography in the early detection of regional wall motion abnormalities (RWMA) in patients presenting with acute myocardial infarction (AMI). The relationship between RWMA and mechanical complications, as assessed by two-dimensional echocardiography, and admission levels of amino terminal fragment of pro-brain natriuretic peptide (NT- proBNP) was also examined.

MATERIAL/METHODS

The study population comprised 226 patients admitted to hospital with a diagnosis of AMI. Echocardiography and NT-proBNP measurements were performed on all patients.

RESULTS

Sixty-eight percent of the patients with AMI were found to have RWMA on echocardiography. Significantly more patients had RWMA within any given range of ejection fraction (EF) (p<0.001), but this difference was most pronounced in those with left ventricular (LV) dysfunction. Mitral regurgitation was the most common complication (48%) seen on echocardiography. The majority of patients (84%) had elevated NT-proBNP levels on admission; this was evident in all categories of EF (p=0.003). In those with normal EF on echocardiography (58%), more patients had elevated levels regardless of the presence of RWMA.

CONCLUSIONS

This study showed that echocardiography is useful in the detection of RWMA in the early stages of AMI. No significant relationship was demonstrated between NT-proBNP levels and RWMA in patients with normal or abnormal LV function. Admission plasma NT-proBNP may, however, be considered as an additional marker in the diagnosis of AMI, especially in those without RWMA.

Rosuvastatin in older patients with systolic heart failure

BACKGROUND

Patients with systolic heart failure have generally been excluded from statin trials. Acute coronary events are uncommon in this population, and statins have theoretical risks in these patients.

METHODS

A total of 5011 patients at least 60 years of age with New York Heart Association class II, III, or IV ischemic, systolic heart failure were randomly assigned to receive 10 mg of rosuvastatin or placebo per day. The primary composite outcome was death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. Secondary outcomes included death from any cause, any coronary event, death from cardiovascular causes, and the number of hospitalizations.

RESULTS

As compared with the placebo group, patients in the rosuvastatin group had decreased levels of low-density lipoprotein cholesterol (difference between groups, 45.0%; P<0.001) and of high-sensitivity C-reactive protein (difference between groups, 37.1%; P<0.001). During a median follow-up of 32.8 months, the primary outcome occurred in 692 patients in the rosuvastatin group and 732 in the placebo group (hazard ratio, 0.92; 95% confidence interval [CI], 0.83 to 1.02; P=0.12), and 728 patients and 759 patients, respectively, died (hazard ratio, 0.95; 95% CI, 0.86 to 1.05; P=0.31). There were no significant differences between the two groups in the coronary outcome or death from cardiovascular causes. In a prespecified secondary analysis, there were fewer hospitalizations for cardiovascular causes in the rosuvastatin group (2193) than in the placebo group (2564) (P<0.001). No excessive episodes of muscle-related or other adverse events occurred in the rosuvastatin group.

CONCLUSIONS

Rosuvastatin did not reduce the primary outcome or the number of deaths from any cause in older patients with systolic heart failure, although the drug did reduce the number of cardiovascular hospitalizations. The drug did not cause safety problems. (ClinicalTrials.gov number, NCT00206310.)

Metabolic syndrome in young Asian Indian patients with myocardial infarction

OBJECTIVES

This study assessed the prevalence of the metabolic syndrome and its impact on hospital outcomes in young South African Indians (< or = 45 years) with acute myocardial infarction (AMI) using both the National Cholesterol Education Programme Adult Treatment Panel III (NCEP ATP III) and the International Diabetes Federation (IDF) definitions.

METHODS AND RESULTS

The study population comprised 389 patients with AMI. The metabolic syndrome as defined by the NCEP ATP III criteria was found in 235 (60%) patients and in 223 (57%) according to the IDF criteria, with only a 79% concordance between the two definitions. However, when ethnic-specific waist circumference cut-offs proposed by the IDF were used as a criterion for obesity in the NCEP ATP III definition, the number of patients with the metabolic syndrome increased significantly to 270 (69%) (p < 0.001). Elevated fasting blood glucose was the major NCEP ATP III determinant present in 86% of individuals. All determinants for both definitions were found more frequently in patients with the metabolic syndrome (p < 0.001). Although 44% of patients had triple-vessel disease on cardiac catheterization studies, the frequency of adverse cardiovascular events during hospital stay was low, and was uninfluenced by the presence or absence of the metabolic syndrome.

CONCLUSION

The metabolic syndrome is a common finding in young Indian patients with AMI who frequently present with extensive atherosclerotic disease. Adverse event rate during hospital stay was low, and was unrelated to the presence of the metabolic syndrome. There was no significant difference in the prevalence rate of the metabolic syndrome as determined by either the NCEP ATP III or IDF definitions, but there was only a moderate level of agreement between the two definitions. Inclusion of ethnic-specific waist circumference cut-offs as the determinant of obesity in the NCEP definition may identify more accurately individuals at increased cardiometabolic risk and improve predication of the metabolic syndrome.

Prognostic value of N-terminal-pro-brain natriuretic peptide measurements in patients with acute coronary syndromes

BACKGROUND

The aim of this study was to examine the prognostic value of admission N-terminal-pro-brain natriuretic peptide (NT-proBNP) measurements for the outcome of adverse events, and to compare it with that of cardiac troponin T in the assessment of risk in patients with acute coronary syndrome (ACS) during the hospital stay and at six months following hospital discharge.

METHODS

The study population consisted of 200 Asian Indian patients admitted with a diagnosis of ACS to the Coronary Care Unit at RK Khan Hospital, Durban, South Africa. A reference group comprising 100 healthy Indian individuals drawn from the same community and who did not suffer from cardiovascular disease was also analysed.

RESULTS

The majority of patients presented with ST segment elevation myocardial infarction (STEMI) (71%), whereas 14.5% had non-ST segment elevation MI (NSTEMI), and the remaining 14.5% had unstable angina. Patients had multiple risk factors for coronary heart disease (CHD) including hypertension (59%), hypercholesterolaemia (59%), smoking (57%), diabetes mellitus (51%), obesity (46%), and a strong family history of CHD (55%). NT-proBNP levels were significantly increased in patients with STEMI (p = 0.005) and NSTEMI (p = 0.002) who developed adverse events during their hospital stay, compared with those who did not. At the six-month followup, although NT-proBNP levels were higher in patients with STEMI and NSTEMI who developed adverse events, these differences were not statistically significant. No differences in troponin T levels were detected in patients with STEMI and NSTEMI who developed adverse events, compared to those who did not, either during the hospital stay, or at six months after release. At hospital admission, 24% of patients with unstable angina who had elevated NT-proBNP levels and normal troponin T concentrations developed adverse events, compared to 38% at six months. NT-proBNP levels in the reference group were comparable with those reported in other populations.

CONCLUSION

This study demonstrated that elevation in admission NT-proBNP levels is an important determinant of acute and intermediate cardiac risk in patients with ACS. NT-proBNP concentrations were superior to those of troponin T as prognostic markers in both STEMI and NSTEMI. In a low-risk group of patients with unstable angina and negative troponin T concentrations, elevated NT-proBNP levels constituted a risk for the development of adverse cardiovascular events. Therefore, NT-proBNP should be included in the risk assessment of ACS to provide guidance for further therapeutic strategies.

Plasminogen activator inhibitor type 1 (PAI-1) and platelet glycoprotein IIIa (PGIIIa) polymorphisms in young Asian Indians with acute myocardial infarction

BACKGROUND

The relationship between polymorphisms in the genes for plasminogen activator inhibitor type 1(PAI-1) and platelet glycoprotein IIIa (PGIIIa), clinical and environmental features, and the risk of premature coronary heart disease (CHD) in Asian Indian subjects living in South Africa, has been investigated.

METHODS

The prevalence of the PAI-1 promoter 4G/5G and the PGIIIa PI A1A2 polymorphisms was examined in 195 unrelated Asian Indian patients ( <or= 45 years) who presented with myocardial infarction (MI). Results were compared with those from 107 unaffected siblings (18-45 years) and 300 healthy age- and race-matched control subjects.

RESULTS

Overall, neither the PAI-1 4G/5G nor the PGIIIa PI A1A2 polymorphism demonstrated an independent risk for MI. No synergistic effect was observed between these two polymorphisms when analysed together. There was a marginal association between the 4G allele of the PAI-1 gene and the risk of MI in individuals who smoked compared with non-smokers (26 vs 11%; p = 0.028; OR 2.74; 95% CI 1.04-8.47). The PGIIIa PI A2 allele was, however, strongly associated with a previous history of MI (17 vs 6%; p = 0.004; OR 3.00; 95% CI 1.38-6.46), as well as the severity of disease as determined by angiography (single/double- vs triple-vessel disease: 3% vs 15%; p = 0.020; OR 0.19; 95% CI 0.02-0.92).

CONCLUSION

In young Asian Indians who smoke, the PAI-1 4G allele is a mild risk factor for the development of MI. The PGIIIa PI A2 allele constitutes a significant risk for individuals who have a previous history of MI, as well as serving as an indicator for the severity of CHD.

Coagulation gene polymorphisms as risk factors for myocardial infarction in young Indian Asians

BACKGROUND

The relationship between pro-coagulant gene polymorphisms, clinical features and the risk of premature coronary heart disease (CHD) in Indian Asian subjects resident in South Africa has been investigated.

METHODS

The prevalence of the beta-fibrinogen -455G/A and -148C/T, and the factor VII 10 bp 5' promoter insertion/deletion and R353Q polymorphisms were examined in 195 unrelated Indian Asian patients (< or = 45 years) who presented with myocardial infarction (MI). Results were compared with those from 107 unaffected siblings (18-45 years) and 300 healthy age- and race-matched control subjects.

RESULTS

Overall, none of the polymorphisms examined here showed any association with MI. However, when stratified according to obesity, patients with a BMI > 30 kg/m2 had a significantly higher frequency of the beta-fibrinogen variant alleles, compared with non-obese patients (19% vs 9%; p = 0.025) and controls (19% vs 9%; p = 0.003). Furthermore, the highest frequency of variant alleles occurred in obese smokers (24%), compared with 4% in non-obese non-smokers (p = 0.003) and 9% in control subjects (p < 0.001). The factor VII R353Q and promoter insertion variants, on the other hand, were associated with higher HDL and lower LDL levels (p = 0.034 and 0.04, respectively).

CONCLUSION

In young Indian Asians who are both obese and smoke, the beta-fibrinogen genetic polymorphisms -455G-->A and -148C-->T, which are in linkage disequilibrium, are significant risk factors for the development of MI. Factor VII genetic variants, namely the 10 bp promoter insertion/deletion and R353Q polymorphisms, may possibly play a protective role through their association with elevated HDL and low LDL levels, respectively.

Demographic data and outcome of acute coronary syndrome in the South African Asian Indian population

Significant differences in the prevalence of coronary heart disease (CHD) exist with respect to gender, age and ethnicity. The disease has been reported to be higher in Indian populations that have emigrated from the Indian subcontinent. The aim of this study was to examine differences in major cardiovascular risk factors and clinical outcome in South African Asian Indians of different age groups and gender, who presented with acute coronary syndromes (ACS). The study cohort consisted of 2 290 consecutive patients, admitted between 1996 and 2002, who were divided into three age subgroups: young ( </= 45 years; 20%), middle age (> 45 to </= 65 years; 59%), and old age (> 65 years; 21%). All three age groups were predominantly male, but this was more evident in the younger (88%) and middle age groups (71%), and became less striking as the proportion of females increased with age. Smoking was more common in young men compared with young women (p < 0.01). Diabetes mellitus (21%) and hypertension (18%) were seen less frequently in young patients but this was confined to men only. Total cholesterol was elevated in 65 to 70% of all patients while high-density lipoprotein (HDL) levels were significantly lower in men compared with women for all age subsets. Hospital mortality was extremely low in young (1%) and middle-aged patients (2%), but was expectedly higher in older patients (8%; p < 0.0001). A family history of CHD was the most common familial vascular disease seen. Young patients were more often subjected to diagnostic and therapeutic interventions. They had more aggressive disease, with 48% of those subjected to angiographic studies having triple vessel disease (TVD), and 14% undergoing coronary artery bypass grafting (CABG). Triple vessel disease was also detected most commonly in middle-aged (64%) and old patients (75%). In conclusion, significant differences in risk factor status were found in South African Indians between genders and for different age groups. Also, young Indians in this study differed markedly from other young population groups with CHD, in that they frequently had premature atherosclerosis with diffuse and aggressive disease.

Lp(a) and apoE polymorphisms in young South African Indians with myocardial infarction

The lipoprotein(a) [Lp(a)] and apolipoprotein E (apoE) polymorphisms have been shown to be important genetic determinants of cardiovascular risk. Their effect on coronary heart disease (CHD) is less clear, particularly in Asian Indians who are at high risk for this disease. The aim of this study was to examine the association of the Lp(a) promoter pentanucleotide repeat polymorphism and the apoE codon 112 and 158 genotypes in 195 young South African Indian patients (< or = 45 years) with myocardial infarction (MI). Results were compared with 300 healthy age-matched control subjects drawn from the same community and 107 unaffected siblings (18-45 years). In addition, fasting lipograms were performed on all patients and a detailed history of conventional risk factors and family background was obtained. Of the six different Lp(a) alleles detected, the 8-repeat sequence was most frequently seen. However, no difference in frequencies existed between patient and control groups. The most frequently occurring apoE genotype in the three study groups was E3/E3 (patients 71%; siblings 70%; controls 70%). A significant difference in the E3/E4 genotype was seen between patients and controls (23% vs 14%; p = 0.018) and between siblings and controls (24% vs 14%; p = 0.027). These patients were also more likely to have significantly higher low-density lipoprotein (LDL) and lower high-density lipoprotein (HDL) levels (p = 0.005 and 0.045, respectively). No association was observed between any of the Lp(a) or apoE genotypes and conventional risk factors such as smoking, diabetes, hypertension, obesity or a family history of CHD. In conclusion, the apoE3/E4 genotype is strongly associated with the incidence of myocardial infarction in young South African Indians. This genotype also adversely affects LDL and HDL cholesterol levels, both of which contribute to premature atherosclerosis. In contrast, the Lp(a) pentanucleotide repeat polymorphism does not appear to have any aetiological role in MI in this population.

Renin-angiotensin system and associated gene polymorphisms in myocardial infarction in young South African Indians

The renin-angiotensin system plays an important role in cardiovascular regulation. Abnormalities in genetic components of this system, such as the angiotensin-converting enzyme (ACE) gene, angiotensin II type 1 (AT1) receptor gene and angiotensinogen (AGT) gene, may cause a variety of adverse cardiovascular effects. It was the aim of this study, therefore, to investigate the involvement of the ACE insertion/deletion (I/D), AT1 receptor 1166 A->C and AGT M235T polymorphisms as predisposing factors for myocardial infarction (MI) in 195 young South African Indians (</= 45 years). Results were compared with those obtained I n 107 unaffected siblings (18-45 years old) and 300 healthy age- and race-matched control subjects. The distribution of the ACE genotypes was the same in each of the three study groups (p-value ranged between 0.83 and 0.98). No differences were observed in the 1166 A->C AT1 receptor polymorphism with respect to both genotype and allelotype (p > 0.70), or in the genotype or allele frequency distribution of the AGT M235T polymorphism (p > 0.44). However, a significant in crease was noted for both the AT1 receptor C variant (p = 0.025) and the AGT T variant (p = 0.047) in hypertensive patients compared with those who were normotensive. In conclusion, results of this study indicate that the ACE I/D, the 1166 A->C AT1 receptor and AGT M235T polymorphisms do not confer any increased risk for MI in young South African Indians.

Haemostatic gene polymorphisms in young indian asian subjects with acute myocardial infarction

BACKGROUND

The relationship between haemostatic gene polymorphisms and arterial disease remains unclear. Much of the evidence gathered so far has been obtained from small heterogeneous studies, resulting in inconsistencies. This study focuses on the South African Indian population which not only represents the largest Indian population outside the Indian subcontinent, but also constitutes a genetically discrete group in whom a high incidence of coronary heart disease occurs.

MATERIAL/METHODS

We investigated the relationship between polymorphisms in the Factor V (Leiden), prothrombin (20210 GgA) and thrombomodulin (Ala455Val) genes in patients with a myocardial infarction (MI) <45 years of age (n=195) and in unaffected siblings (n=107) and unrelated healthy race-matched individuals drawn from the same community (n=300).

RESULTS

The Factor V Leiden mutation was found to occur with a frequency of less than 1%, while the prothrombin 20210 GgA polymorphism was not observed in any of the individuals in this study. In contrast, the variant thrombomodulin Val allele occurred with a frequency similar to that reported in Caucasians. The frequency of this allele in both patients with MI and their siblings was marginally higher than in healthy controls, but the difference did not reach statistical significance. However, in patients who smoked, the thrombomodulin variant allele occurred significantly more frequently than in the non-smoking group (p=0.044).

CONCLUSIONS

The Leiden Factor V and prothrombin 20210 GgA polymorphisms have no value in disease association studies in the Indian Asian population. In smokers, the thrombomodulin Ala455Val variant allele emerges as a significant risk factor for coronary heart disease.

Risk factors and methylenetetrahydrofolate reductase gene polymorphisms in a young South African Indian-based population with acute myocardial infarction

Although coronary heart disease (CHD) is extremely common in South African Indians, there is little published data on the possible causes leading to myocardial infarction (MI) in young Indians. The aim of this study was to identify common environmental risk factors and to examine the relationship between two polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene, the 677 C right arrow-hooked T and 1298 A right arrow-hooked C in young South African Indians with MI. Demographic and risk factor data were obtained from245 patients </= 45 years with MI who were admitted to the RK Khan Hospital, Durban. Venous blood from 195 of the 245 patients with MI, as well as from the sublings of the MI patients (n = 107), and 300 healthy age-matched Indian control subjects, were collectd from genetic analysis. Cigarette smoking was the most important risk factor, occurring in three-quarters of patients, followed by dyslipidaemia in half of the subjects. Diabetes (19%) and hypertension (22%) were found not to be major risk factors for MI. A strong familial link was observed not only for a history of CHD (54%), but also for diabetes (42%) and hypertension (41%). No difference was found in the thermolabile variant of the MTFHR gene (677 C right arrow-hooked T) or the second variant 1298 A right arrow-hooked C between controls and patients with MI or their siblings. The two polymorphisms did not appear to work in synergy, neither was there any relationship to common risk factors for CHD. In conclusion, smoking, dyslipidaemia and obesity were the most common phenotypic risk factors for MI. Neither the 667 C right arrow-hooked T nor the 1298 A right arrow-hooked C MTFHR variants appeared to be risk factors for premature CHD in this group.

Acute myocardial infarction in a young South African Indian-based population: patient characteristics on admission and gender-specific risk factor prevalence

BACKGROUND

Myocardial infarction (MI) is a complex disease caused by interaction of a number of genetic and environmental factors. This disease has reached epidemic proportions in South African Indian descendants. The aim of this study was to survey the prevalence of coronary heart disease risk factors in a sub-group of young Indian patients (< or = 45 years) who presented to the Coronary Care Unit at the R. K. Khan Hospital in Durban, a major referral centre for patients with acute MI in the province of Natal.

METHODS AND RESULTS

A total of 245 patients < or = 45 years of age were recruited from patients consecutively admitted to the Coronary Care Unit at the R. K. Khan Hospital, Durban, KwaZulu Natal, South Africa between 1996 and 1999 with a diagnosis of acute MI. All patients were of Indian origin living in the Durban area in the province of KwaZulu-Natal. Demographic and risk factor data were obtained from all patients and included anthropometric measures, family history and the traditional cardiovascular risk factor assessment (smoking, lipids, hypertension, and diabetes mellitus). Clinical data included in-hospital presentation, management and complications and angiographic classification of coronary atherosclerosis. The most prevalent risk factors were previous: smoking (74%), and hypertriglyceridaemia (54%). Only 14% of the population presenting with an acute MI were women. Smoking was more common among men (81%) than in women (35%). Abnormal high density lipoprotein (HDL) cholesterol levels were detected in 38% of the patients with a dear gender difference: 43% and 9%, in men and women, respectively. In contrast hypertension was more prevalent in young women with MI than in men: 38% and 19%, respectively. Coronary angiography was performed in 79 patients on admission; a single vessel stenosis was found in 28%, two vessel disease in 20% and triple vessel disease in 52%, respectively. On admission, 92% of patients were in Killip class I. Overt heart failure and cardiogenic shock were uncommon and were seen in 3.3% and 0.8%, respectively. Patients who received thrombolytic therapy had fewer complications (8%) compared to those who did not (11%). However, the difference towards a benefit of thrombolysis did not reach significance. Recurrent angina (6%) was the commonest complication, while ventricular arrhythmias were observed in 2% of patients. There was a strong familial link: 54% of the patients had a family background of coronary heart disease (CHD) while 42% and 41% had family members who suffered from diabetes mellitus and hypertension, respectively.

CONCLUSION

Smoking and dyslipidaemia (predominantly hypertriglyceridaemia, and low HDL-cholesterol) were the most common cardiovascular risk factors of MI in young South African Indians. A strong familial link was observed not only for a history of CHD/MI, but also for hypertension and diabetes mellitus, supporting a genetic basis for the development of premature CHD. Therefore, further analysis of potential genetic factors such as variance of genes involved in vascular homeostasis, haemostatic factors, lipid metabolism and other metabolic factors seems warranted.

Cigarette smoking is independently associated with markers of endothelial dysfunction and hyperinsulinaemia in nondiabetic individuals with coronary artery disease

BACKGROUND

Oxidative stress and endothelial dysfunction have been introduced as a unifying pathological mechanism for early atherosclerotic disease. They are caused by a variety of stimuli including cigarette smoking (environmental) and type 2 diabetes (disease factor). However, the role of hyperinsulinemia, a marker of insulin resistance, as a risk factor for atherosclerosis remains to be clarified.

STUDY OBJECTIVES

To study the relationship of smoking, hyperinsulinaemia and biochemical markers of oxidative stress and endothelial dysfunction, in patients with coronary artery disease.

DESIGN

Case-control study of 5-year survivor status in smokers, former smokers and nonsmokers with angiographically documented stable coronary artery disease classified by self-reporting of smoking status together with plasma cotinine measurements.

SETTING

Cardiology and cardiac surgery unit of a tertiary care referral centre.

PATIENTS AND METHODS

Plasma levels of vitamins C, E and selenium, and the adhesion molecules E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were assessed in 214 patients at baseline together with the glucose and insulin response to an oral glucose challenge. Sixty known or newly diagnosed type 2 diabetic patients (28%) were identified and excluded from further analysis.

RESULTS

E-selectin and ICAM-1, serving as markers of endothelial dysfunction, significantly correlated with hyperinsulinaemia (p < 0.05). Circulating immunoreactive insulin was elevated in active smokers and former smokers as compared to non-smokers after an oral glucose load (p < 0.05 for the area under the insulin time curve), despite a similar glucose response. Smoking was associated with a decrease in antioxidant vitamins C (p = 0.02) and E (p = 0.03), and an increase of E-selectin (p < 0.05) and ICAM-1 (p < 0.001). Low baseline ICAM-1 and high vitamin C levels emerged as the most significant multivariate predictors of 5-year survival (p < 0.001).

CONCLUSIONS

Hyperinsulinaemia in smokers is linked with markers of endothelial dysfunction. Impaired vascular reactivity can thus be a new possible mechanism linking insulin resistance and smoking.