Impact of atherosclerosis-related gene polymorphisms on mortality and recurrent events after myocardial infarction

Although previous epidemiologic studies have suggested an association between the onset of myocardial infarction (MI) and some genetic variations, the impact of these variants on recurrent cardiovascular events after MI has not been fully elucidated. We genotyped 87 polymorphisms of 73 atherosclerosis-related genes in consecutive acute MI patients registered in the Osaka Acute Coronary Insufficiency Study and compared the incidence of death and major adverse cardiac events (MACE) among the polymorphisms of each gene. After initial screening in 507 patients, we selected nine polymorphisms for screening in all 1586 patients. Multivariate Cox regression analysis revealed that G allele carriers at the position 252 of the lymphotoxin alpha (LTA) gene were independently associated with an increased risk of death (hazard ratio [HR]: 2.46; 95% CI: 1.24-4.86). In conclusion, a 252G allele of LTA is associated with an increased risk of death after AMI and may be a useful genetic predictor.

[Effect of successful late reperfusion by primary coronary angioplasty on mechanical complications of acute myocardial infarction]

It has been suggested that early treatment decreases, but late treatment increases, the risk of mechanical complications for a thrombolytic strategy. However, few studies have evaluated whether late reperfusion by primary coronary angioplasty decreases the risk of mechanical complications. A total of 2,209 patients with acute myocardial infarction treated with primary coronary angioplasty within 24 hr after the onset of symptoms were divided into three groups: early reperfusion (ER; <- 12 hr, n = 1,647), late reperfusion (LR; > 12 hr, n = 219), and failed reperfusion (RF; n = 343). We evaluated the incidence, risk ratio, and predictors of mechanical complication. The overall incidence of mechanical complications was 2.0%. The incidence of mechanical complications was highest in the FR group (ER 1.4%, LR 1.8%, FR 5.0%, p <0.01). After adjusting for clinical variables, the risk ratio for mechanical complications increased in the FR group compared with LR group [risk ratio 7.34, 95% confidence interval (CI) 1.02 - 52.80, p = 0.04]. Predictors of an increased risk of mechanical complications by multivariate analysis were age >- 70 years (odds ratio 3.68, 95% CI 1.56-8.64, p < 0.01), Killip class >- II (odds ratio 3.73, 95% CI 1.52-9.12, p >- 0.01), absence of collateral vessels (odds ratio 4.09, 95% CI 1.17-14.26, p = 0.03), and FR (odds ratio 2.68, 95% CI 1.01-6.61, p = 0.03). In conclusion, successful late reperfusion by primary coronary angioplasty is associated with the reduced risk of mechanical complications in patients with acute myocardial infarction.

Predictors of Length of Hospital Stay After Acute Myocardial Infarction in Japan

BACKGROUND

In Western countries, the length of hospital stay after acute myocardial infarction (AMI) has decreased dramatically during the past 3 decades and is now approximately 1 week. However, epidemiological data concerning the length of hospital stay, its predictors and trends based on a large-scale sample are still limited in Japan.

METHODS AND RESULTS

The study group comprised 4,113 surviving AMI patients who were enrolled in the Osaka Acute Coronary Insufficiency Study from April 1998 to March 2003. The mean length of hospital stay was 31.2 days. Clinical factors (patient characteristics, severity of infarction, therapy, and in-hospital complications) only explained 26% of the variation in hospital stay. The mean hospital stay was significantly longer in 1998 than in 2002. In 2002, occupational status and admission to a high-volume hospital were independent predictors of a shorter hospital stay, but this association was not observed in 1998.

CONCLUSIONS

The hospital stay is still extremely long in Japan and clinical factors do not provide an explanation. The findings of the present study suggest that the hospital stay could be reduced in some patients with AMI, but randomized studies are needed to examine the feasibility of early discharge.

Prognostic significance of atrial fibrillation/atrial flutter in patients with acute myocardial infarction treated with percutaneous coronary intervention

Atrial fibrillation (AF) is a frequent complication after acute myocardial infarction (AMI) that has been associated with increased in-hospital and long-term mortality rates in the prethrombolytic and thrombolytic eras. Current therapies, including percutaneous coronary intervention (PCI), are effective in reducing mortality in patients with AMI. However, little is known concerning the incidence and prognostic significance of AF in patients with AMI who are treated with PCI. We evaluated 2,475 consecutive patients with AMI who underwent PCI within 24 hours after onset and who were enrolled in the Osaka Acute Coronary Insufficiency Study. Patients were categorized into 2 groups according to the presence of AF or atrial flutter. The incidence of AF was 12.0%. Patients with AF were older, were in higher Killip classes, had higher rates of previous myocardial infarction and previous cerebrovascular disease, had systolic blood pressure of <100 mm Hg and heart rates of > or =100 beats/min, multivessel disease, and had poorer reperfusion of the infarct-related artery than those without AF. Patients with AF had higher in-hospital (16.0% vs 6.7%, p <0.001) and 1-year (18.9% vs 7.9%, p <0.001) mortality than those without AF. Multivariate Cox regression analysis revealed that AF was an independent predictor of 1-year mortality (hazard ratio 1.64, 95% confidence interval 1.05 to 2.55) but was not a predictor of in-hospital mortality. AF is a common complication in patients with AMI who are treated with PCI and independently influences 1-year mortality.

Effect of successful late reperfusion by primary coronary angioplasty on mechanical complications of acute myocardial infarction

It has been suggested that early treatment decreases, but late treatment increases, the risk of mechanical complications for a thrombolytic strategy. However, few studies have evaluated whether late reperfusion (LR) by primary coronary angioplasty decreases the risk of mechanical complications. A total of 2,209 patients with acute myocardial infarction treated with primary coronary angioplasty within 24 hours after the onset of symptoms were divided into 3 groups: early reperfusion (ER; < or =12 hours, n = 1,647), LR (>12 hours, n = 219), and failed reperfusion (FR; n = 343). We evaluated the incidence, risk ratio, and predictors of mechanical complications. The overall incidence of mechanical complications was 2.0%. The incidence of mechanical complications was highest in the FR group (ER 1.4%, LR 1.8%, FR 5.0%; p <0.01). After adjusting for clinical variables, the risk ratio for mechanical complications increased in the FR group compared with the LR group (risk ratio 7.34, 95% confidence interval [CI] 1.02 to 52.80; p = 0.04). Predictors of an increased risk of mechanical complications by multivariate analysis were age > or =70 years (odds ratio [OR] 3.68, 95% CI 1.56 to 8.64; p <0.01), Killip class > or =II (OR 3.73, 95% CI 1.53 to 9.12; p <0.01), absence of collateral vessels (OR 4.09, 95% CI 1.17 to 14.26; p = 0.03), and FR (OR 2.68, 95% CI 1.09 to 6.61; p = 0.03). In conclusion, successful LR by primary coronary angioplasty is associated with the reduced risk of mechanical complications in patients with acute myocardial infarction.

Joint effects of Chlamydia pneumoniae infection and classic coronary risk factors on risk of acute myocardial infarction

BACKGROUND

Although not in itself strongly predictive of coronary heart disease, Chlamydia pneumoniae infection could interact with classic risk factors in determining risk of acute myocardial infarction (AMI).

METHODS

We assessed C pneumoniae immunoglobulin (Ig) G and IgA titers and classic risk factors in 618 patients with AMI and in 967 controls.

RESULTS

IgG titers were not related to AMI, but a significant association was seen between IgA titers and AMI. Excess risk of AMI was noted mainly among patients with the highest IgA titers, such as those beyond 2.88 (the 95th percentile cutoff point in control subjects), showing a 1.8-fold increase in risk (odds ratio 1.75, 95% CI 1.04-2.92). Classic risk factors did not differ between subjects with IgA titers above and below the 95th percentile cutoff. However, in multivariate analyses, models incorporating both IgA titers and a classic risk factor such as obesity, hypercholesterolemia, or smoking predicted risk more effectively than single-parameter models. For example, the odds ratio for AMI among subjects with the highest IgA titers plus hypercholesterolemia was greater than the product of individual risks associated with these high IgA titers and with hypercholesterolemia.

CONCLUSIONS

Interactions with classic risk factors (ie, obesity, hypercholesterolemia, and smoking), increased the predictive value of C pneumoniae IgA antibody titers in determining risk of AMI.

Impact of high-sensitivity C-reactive protein on predicting long-term mortality of acute myocardial infarction

Although the C-reactive protein (CRP) concentration measured shortly after acute myocardial infarction (AMI) is associated with infarct size, its prognostic value is controversial. The reduction of CRP is accelerated by reperfusion. Therefore, the CRP concentration, measured during the stable phase of AMI in patients treated predominantly with reperfusion therapies, may be independent of infarct size and may predict long-term mortality. We studied 1,309 patients with AMI enrolled in the Osaka Acute Coronary Insufficiency Study between April 1999 and June 2001. CRP was measured during the stable phase (mean 25 days after AMI onset). The patients were followed for an average of 522 days. Reperfusion therapies were performed in 90% of the patients. Patients in the highest quartile of CRP values (> or =0.38 mg/dl) were older, had higher prevalences of diabetes mellitus, and had higher Killip classes than patients in the lower 3 quartiles (<0.38 mg/dl). Multivariate logistic regression analysis revealed that CRP was independently associated with age and the absence of revascularization therapies. Patients in the highest quartile had a higher long-term mortality rate than patients in the lower 3 quartiles (8.9% vs 2.0%; p <0.001). Multivariate Cox regression analysis revealed that the highest quartile of CRP values was an independent predictor of long-term mortality (hazard ratio 4.94, 95% confidence interval 1.13 to 21.6). We conclude that CRP measured during the stable phase of AMI is not associated with infarct size in the reperfusion era but is significantly associated with long-term mortality of AMI.

Variation during the week in the incidence of acute myocardial infarction: increased risk for Japanese women on Saturdays

BACKGROUND

Variations in the incidence of acute myocardial infarction during the week may differ between and within communities, according to lifestyle.

OBJECTIVE

To identify potential triggering factors for acute myocardial infarction by examining variations in incidence in the days of the week within the Osaka area of Japan.

PATIENTS

Of 2511 consecutive patients in this region who were admitted to hospital for acute myocardial infarction between April 1998 and March 2001 and consented to take part, 2400 who had a definitely identified time of onset were enrolled.

RESULTS

For this group as a whole, no significant difference in incidence was noted between days of the week. However, in subgroup analyses women were shown to have significant variation through the week, peaking on Saturday with a 39% increase in relative risk (p = 0.037); working subjects showed a peak on Monday, with a 26% increase in relative risk (p = 0.038). Stratified analyses showed that in working men there was a prominent Monday peak in the onset of infarction, with a 30% increase in relative risk (p = 0.022), while in working women, there was no significant variation through the week.

CONCLUSIONS

Earlier findings of a Monday peak linked to increased physical and mental occupational stress are confirmed. There is also an increase in uncertain risk factors on Saturdays for Japanese women, possibly involving a stressful weekend burden for women. Confirmation of this finding in other communities may help identify triggers of acute myocardial infarction and be useful in prevention.

Prevalence of Helicobacter pylori infection and its link to coronary risk factors in Japanese patients with acute myocardial infarction

The association between Helicobacter pylori (H. pylori) infection and coronary artery disease, as well as the association between H. pylori infection and classic coronary risk factors, is controversial in patients from Western countries. The high prevalence of H. pylori infection in Japanese subjects enables an examination of these associations in a large population, especially in young patients, because coronary risk factors may be more strongly associated with younger individuals than with older individuals. The IgG seropositivity to H. pylori was assessed in 618 cases with acute myocardial infarction (AMI) and in 967 controls. The prevalence of seropositivity to H. pylori was similar between cases and controls, but in subjects younger than 55 years, the rate was significantly higher in cases than in controls (58.7% vs 43.3%, p = 0.009). After adjustment for age, gender, diabetes mellitus, hypertension, smoking, body mass index, total cholesterol, and high density lipoprotein cholesterol, the odds ratio for acute myocardial infarction was 2.97 (95% confidence interval, 1.37-6.41; p = 0.006). Worsening of classic coronary risk factors was not associated with H. pylori infection in subjects younger than 55 years. These results suggest that in younger individuals in Japan, H. pylori infection is significantly associated with AMI independent of the classic coronary risk factors.

Depressive symptoms predict 12-month prognosis in elderly patients with acute myocardial infarction

BACKGROUND

Several studies have associated depressive symptoms with an increased risk for cardiac events after the onset of acute myocardial infarction (AMI). The aim of the present study is to investigate the impact of the depressive symptoms on prognosis of the elderly patients with AMI.

METHOD

Depression was assessed in consecutive patients with AMI (n = 1042; mean age 63 +/- 11 years) using the Zung Self-Rating Depression Scale (SDS). Patient with a score > or = 40 was classified as having depressive symptoms. Cardiac events (cardiac death, nonfatal re-MI, coronary angioplasty or bypass surgery, readmission for heart failure, unstable angina, or uncontrolled arrhythmia) were examined during 12 months follow-up period.

RESULTS

Depressive symptoms were observed in 438 patients (42.0%). Prevalence of depression was not dependent of age (P = 0.60) and gender (P = 0.91). The rate of cardiac events was 31.2% per year in patients with depressive symptoms whereas 23.9% per year in patients without depressive symptoms. Multiple logistic regression analyses showed that depression was significantly associated with 1-year cardiac events (odds ratio 1.41, 95% CI 1.03 to 1.92, P = 0.03) after controlling for age, gender, severity of myocardial infarction, coronary risk factors, e.g. hypertension, diabetes mellitus and smoking habits. Depression was a significant risk factor for the cardiac events (log rank, P = 0.02) in the elderly patients (> or = 65 years old, 501 patients). However, the association of depression with cardiac events in the young patients (< 65 years old, 541 patients) was not statistically significant (P = 0.11).

CONCLUSION

Depression after AMI is a significant predictor of 1-year cardiac events for Japanese population, and its presence augments the risk especially in the elderly patients.

Muscle pump-dependent self-perfusion mechanism in legs in normal subjects and patients with heart failure

Leg venous pressure markedly falls during upright exercise via a muscle pump effect, creating de novo perfusion pressure. We examined physiological roles of this mechanism in increasing femoral artery blood flow (FABF) and its alterations in chronic heart failure (CHF). In 10 normal subjects and 10 patients with CHF, standard hemodynamic variables, mean ankle vein pressure (MAVP), and FABF with Doppler techniques were obtained during graded upright bicycle exercise. To evaluate a nonspecific blood flow response, normal subjects also performed supine exercise. In normal subjects, MAVP rapidly declined by 45 mmHg and FABF correspondingly increased 5.3-fold without a systemic pressor response during 10 s of light upright exercise at 5 W. Approximately 67% of the blood flow response was attributed to the venous pressure drop-dependent mechanism. In CHF patients, MAVP declined by only 36 mmHg and FABF increased only 1.7-fold during the same upright exercise. The muscle venous pump has an ability to increase FABF at least threefold via the venous pressure drop-dependent mechanism. This mechanism is impaired in CHF patients.

Circadian variation of the onset of acute myocardial infarction in the Osaka area, 1998-1999: characterization of morning and nighttime peaks

The onset of acute myocardial infarction (AMI) shows characteristic circadian variations; that is, a definite morning peak related to biologic rhythms and a vague nighttime peak related to socioeconomic factors. The recent economic recession in Japan may change the circadian variation, especially the nighttime peak. This study evaluated the recent circadian variation of AMI in Osaka and specified the patient subgroups showing either a morning or nighttime peak predominantly. Of 1,609 consecutive patients with AMI registered from April 1998 to January 2000, 1,252 whose onset of AMI was definitely identified were studied. The day was divided into six 4-h periods with a morning peak between 08.01 h and 12.00h, and nighttime peak between 20.01 h and 24.00h. When subgroup analysis was performed, female patients aged 65 years or more showed a morning peak alone and male patients aged less than 65 years with an occupation and the habits of cigarette smoking and alcohol intake showed a nighttime peak alone. Thus, in Osaka nighttime socioeconomic factors may currently be more potent triggers of AMI than the morning surges in younger male workers who smoke and drink.

Occurrence of sustained increase in QT dispersion following exercise in patients with residual myocardial ischemia after healing of anterior wall myocardial infarction

Our objective was to evaluate the effect of exercise on QT dispersion over the next 3 hours, as seen on a standard 12-lead electrocardiogram in patients with healed myocardial infarction with or without residual ischemia. We measured QT and QTc dispersion before, immediately after, and 1 and 2 hours after symptom-limited, dynamic treadmill exercise tests in 28 patients with healed anterior wall myocardial infarction with (group I, n = 18) and without (group II, n = 10) residual ischemia. The same protocol was followed in 5 group I patients after successful performance of coronary angioplasty. QT and QTc dispersion did not change immediately after exercise in group II. These parameters increased in group I (QT dispersion at rest [mean +/- SD] 57 +/- 22 ms, and after exercise 87 +/- 27 ms; QTc dispersion at rest 62 +/- 25 ms, and after exercise 114 +/- 36 ms). The increases in QT and QTc dispersion were sustained for at least 2 hours. After a successful coronary angioplasty in 5 patients, these parameters no longer increased with exercise. Thus, QT dispersion increased for at least 2 hours after exercise in patients who had residual ischemia after healing of myocardial infarction. Data obtained in 5 of these patients after coronary angioplasty support the idea that residual ischemia plays a key role in the sustained increase in QT dispersion after exercise.

[Recovery process from myocardial stunning after transient ischemia: assessment with pulsed wave Doppler transmitral flow pattern]

Sustained left ventricular systolic dysfunction after transient myocardial ischemia is well known as "myocardial stunning", but little is known about the recovery in left ventricular diastolic function. Changes in left ventricular systolic and diastolic performance following dobutamine-induced ischemia were investigated in 13 patients with chest pain syndrome and normal coronary arteries (control) and 34 patients with coronary artery disease. Two-dimensional echocardiography and pulsed wave Doppler transmitral flow velocity curves were recorded at baseline, after infusion of a peak dose of dobutamine and at 20 min and 2 hours after dobutamine infusion. In control subjects, left ventricular ejection fraction and the peak early diastolic filling velocity increased at the peak dose of dobutamine. At 20 min after the cessation of dobutamine infusion, these values were restored to the baseline levels. In patients with coronary artery disease, ejection fraction and peak velocity increased at the peak dose of dobutamine but decreased at 20 min after infusion compared with baseline values despite the restoration of heart rate and blood pressure. Although ejection fraction increased at 2 hours compared with 20 min after infusion, peak velocity did not increase. Left ventricular diastolic dysfunction may be sustained longer than systolic dysfunction after transient myocardial ischemia.