Coronary angiography and pathogenesis of coronary artery disease in young male survivors of myocardial infarction

Vascular Disease in Young Indians (20-40 years): Role of Ischemic Heart Disease

Coronary Artery Disease (CAD) occurs at a younger age in Indians with over 50% of Cardiovascular Disease (CVD) mortality occurring in individuals aged less than 50 years. Although several risk factors have been suggested; smoking, dyslipidemia and hypertension are major risk factors in the young. In this review, we have pooled the current evidence on Ischemic Heart Disease (IHD) in young (20-40 years) and provided an opinion for the effective management of IHD in young Indians.

Comparison of angiographic findings, risk factors, and long term follow-up between young and old patients with a history of myocardial infarction

We compared the angiographic findings, coronary risk factors and five years prognosis in 200 patients < or =45, and 260 patients >45 years old who where admitted with an acute myocardial infarction. We found that family history and smoking were the most common risk factors in patients < or =45 years old P<0.04, P<0.0001, respectively, and hypertension and diabetes mellitus were more prevalent in patients >45 years, P<0.00001 for both. Young patients had a higher incidence of normal coronary arteries and a lesser one of triple vessel disease in comparison with old ones P<0.001 and P<0.04, respectively. There was also a tendency for young patients to have a higher frequency of single vessel disease. The long-term prognosis was favourable in the younger age group since the survival rate was much better, as well as the quality of life. Death in the young patients seems to be very often electrical owing to sudden ventricular fibrillation, whereas death in the elderly is more often associated with congestive heart failure.

Clinical and biochemical factors associated with prognosis after myocardial infarction at a young age

OBJECTIVES

This study examined the effect of metabolic disturbances, hemostatic function, coronary artery disease severity and left ventricular function on the long-term prognosis after myocardial infarction in men < 45 years old.

BACKGROUND

Heavy smoking; dyslipoproteinemias involving very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL); a family history of premature coronary artery disease; hyperinsulinemic responses to oral and intravenous glucose challenges; and defective fibrinolytic function characterize the young postinfarction patient, but the influence of these features on the long-term prognosis is virtually unknown.

METHODS

Measurements of hemostatic function and metabolic and angiographic indicators of risk were included in a prospective cohort study of variables predictive of reinfarction, cardiac death and major coronary events within 6 to 9 years in 108 unselected nondiabetic men with a first myocardial infarction before age 45 years.

RESULTS

During follow-up, 20 patients had sudden cardiac death, and 53 had a major coronary event (reinfarction, sudden cardiac death, bypass surgery or intervention by catheterization). In multivariate analysis, VLDL and global coronary atherosclerosis score predicted reinfarction; plasma plasminogen activator inhibitor-1 (PAI-1) activity and global coronary stenosis score predicted cardiac death; and VLDL triglyceride levels, global coronary atherosclerosis score and age predicted any major coronary event.

CONCLUSIONS

This prospective cohort study shows that hypertriglyceridemia, impaired fibrinolytic capacity secondary to plasma PAI-1 activity elevation and extensive coronary artery disease increase the risk of recurrences in men with a first myocardial infarction before age 45 and contribute to the relatively poor long-term prognosis in this patient group.

Acute myocardial infarction in young and very old Chinese adults: clinical characteristics and therapeutic implications

To characterize acute myocardial infarction (AMI) in young adults and octogenarians, 475 AMI patients, in age subsets, were examined. The clinical features, risk factors and in-hospital mortality were compared among 17 young patients (< 40 years), 426 patients of common age (40-79 years), and 32 very elderly patients (> or = 80 years). The octogenarian patients were mainly female (male/female ratio, 0.9 vs. 4.7 in other subgroups, P < 0.005), and had more frequent atypical presentation and postinfarctional congestive heart failure; whereas infarct size, location and development of Q-wave, major arrhythmias and cardiac wall rupture were not different among these age subsets. The most common risk factors in the young group were dyslipidemia (67%) and cigarette smoking (65%), and in the octogenarian group were dyslipidemia (52%) and hypertension (50%). Among age subsets, however, the prevalence of risk factors was not significantly different except for a relatively lower smoking rate in the octogenarians. Compared with 40- to 79-year-old patients who had predominantly multi-vessel diseases, the young patients had milder coronary atherosclerosis and were more likely to have normal coronaries (27% vs. 5%, P < 0.01). Significantly more octogenarians than young patients succumbed to AMI in the hospital (44% vs. 18%, P < 0.005), usually because of a cardiogenic complication (93%). Also, the octogenarians were less likely than the younger patients to have received thrombolytic therapy, mostly because of delayed diagnosis and arrival at the hospital, or because of old age itself.(ABSTRACT TRUNCATED AT 250 WORDS)

Postprandial lipoproteins and progression of coronary atherosclerosis

The relations between triglyceride-rich lipoproteins, alimentary lipaemia and coronary heart disease (CHD) have remained obscure and much debated. We studied the basal and postprandial plasma levels of chylomicron remnants and very low density lipoproteins (VLDL) of varying particle size in 32 male postinfarction patients (mean (S.D.) age 48.8 (3.2) years) and in 10 age-matched control men. The selective quantification of postprandial intestinal and hepatic lipoproteins was accomplished by determining apolipoproteins B-48 and B-100 in lipoprotein subfractions of Svedberg flotation (Sf) rates > 12 before and 3, 6 and 12 h after an oral fat load. Since all patients had undergone two coronary angiographies with an intervening time interval of around 5 years, lipoprotein fractions were examined in relation to the global severity as well as the rate of progression of coronary lesions. The postprandial plasma levels of small chylomicron remnants (Sf 20-60 apolipoprotein B-48) were found to relate distinctly to the rate of progression of coronary lesions between the angiographies (r = 0.51, P = 0.01). Adjustment for the possible confounding effect of the HDL cholesterol and dense LDL apolipoprotein B concentrations did not substantially alter the strength of this association. Neither the increment of plasma triglyceride during the postprandial period nor the concentrations of other lipoprotein fractions closely reflected the amount of small chylomicron remnants in the circulation or correlated with progression of coronary lesions. Our data suggest that small chylomicron remnants are implicated in the progression of coronary artery disease.

Does diffuse coronary atherosclerosis affect the relation between coronary stenoses and uptake of thallium-201 after exercise?

It has been proposed that diffuse coronary atherosclerosis influences the myocardial perfusion. We performed a study of 94 young men with previous myocardial infarction in order to find out whether the presence and extent of diffuse coronary atherosclerosis affected the relation between maximal stenosis and myocardial perfusion in areas remote from the infarction. The patients were examined by planar-imaging thallium-201 scintigraphy, following exercise, and coronary angiography within 6 months after myocardial infarction. The maximal distinct stenosis and diffuse coronary atherosclerosis, comprising both plaque size and extent, were semiquantitatively assessed. The correlation coefficients between maximal stenosis within the LAD, RCA, and LCX vascular territories and the corresponding initial uptake of thallium were 0.52 (P = 0.0001), 0.30 (P = 0.04), and 0.46 (P = 0.02), respectively. No change of the correlations was found, except for a slight increase of the r-value from 0.30 to 0.37 in regions corresponding to RCA, after controlling for the diffuse atherosclerosis score in a multiple stepwise regression analysis. These findings indicate no impact of diffuse coronary atherosclerosis on regional myocardial perfusion in areas remote from the infarction.