Stroke following acute myocardial infarction in diabetics

Stroke in the patient with diabetes (part 1) - Epidemiology, etiology, therapy and prognosis

There is a higher incidence of stroke in both the type 2 diabetic and the non-diabetic insulin resistant patient which is accompanied by higher morbidity and mortality. The increase in the frequency of stroke is due to an increase in cerebral infarction, mainly lacunar infarcts, with the incidence of cerebral hemorrhage being less frequent. The major risk factors for stroke in the type 2 diabetic patient are age, hypertension, the number of features of the Metabolic Syndrome, the presence of diabetic nephropathy in both the type 1 and type 2 patient, the presence of peripheral and coronary artery disease and especially the presence of atrial fibrillation. Hyperglycemia is associated with a poor outcome from stroke but is not causative.

Safety and tolerability of duloxetine treatment of diabetic peripheral neuropathic pain between patients with and without cardiovascular conditions

BACKGROUND

Diabetic patients are predisposed to cardiovascular (CV) disease and other chronic medical conditions. We compared the safety of duloxetine in patients with (CV-positive) and without (CV-negative) historical/comorbid cardiovascular conditions at study entry.

METHODS

Data were pooled from three double-blind studies in which patients (age > or =18 years) with diabetic peripheral neuropathic pain (DPNP) were randomized to 12 weeks of duloxetine (DLX) 60 mg qd (n=344), 60 mg bid (n=341), or placebo (PBO, n=339). Safety assessments included discontinuation rates, spontaneously reported treatment-emergent adverse events (TEAEs), changes in vital signs, and changes in lab analytes.

RESULTS

Mean age of CV-positive patients (n=762) vs. CV-negative patients (n=262) was 61.1 vs. 56.1 years. The most common historical or comorbid CV conditions were hypertension, coronary artery disease, and myocardial infarction. Discontinuation due to adverse events was higher for DLX than for PBO in both CV-positive and CV-negative patients (13.5% DLX, 6.0% PBO, and 14.3% DLX, 3.4% PBO, respectively). Rates of CV-related TEAEs in CV-positive (8.4% DLX; 9.9% PBO) and CV-negative (8.6% DLX; 5.7% PBO) patients were similar (P>.1). Mean changes in blood pressure for each DLX dose vs. PBO between CV-positive and CV-negative patients were not statistically significant (P>.1), nor were sustained hypertension rates between CV-positive (2.4% DLX; 2.8% PBO) and CV-negative (2.9% DLX; 4.7% PBO) patients.

CONCLUSIONS

In this analysis, the safety of duloxetine in patients with DPNP was not found to be significantly different between patients with and without historical or comorbid CV conditions.

The incidence of stroke after myocardial infarction: a meta-analysis

PURPOSE

While the risk of stroke after myocardial infarction (MI) is increased compared with the risk among those without MI, the magnitude of this risk remains unclear. Although numerous clinical trials have reported the incidence of stroke following MI, these are among selected populations. We reviewed cohort studies reporting the incidence of stroke after MI to better define the risk of ischemic stroke in an unselected population.

METHODS

A computerized literature search (MEDLINE and PubMed) and manual review of reference lists of identified articles were conducted. Population-based studies published from 1978-2004 with at least 100 subjects that reported number or percent of ischemic strokes experienced by MI survivors were identified. Data were extracted using standardized forms, and study quality was assessed by 2 independent reviewers. Ischemic stroke rates were reported as number of events per 1000 MI with 95% confidence intervals (CI) calculated by Poisson distribution. A combined stroke rate was calculated for in-hospital, 30 days, and 1-year post-MI using weights of 1/variance. A random-effects model also was created to estimate in-hospital stroke rate. Variability in study designs and outcome definitions limit synthesis of available data.

RESULTS

During hospitalization for the index MI, 11.1 ischemic strokes occurred per 1000 MI compared with 12.2 at 30 days and 21.4 at 1 year. Using a random-effects model, 14.5 strokes occurred per 1000 MI. Positive predictors of stroke after MI included: advanced age, diabetes, hypertension, history of prior stroke, anterior location of index MI, prior MI, atrial fibrillation, heart failure, and nonwhite race.

CONCLUSIONS

The public health implications of stroke among MI survivors, as well as the large number of MI survivors, underscore the need to be aware of this devastating complication. Further research is needed to determine the optimal stroke prevention strategies for MI survivors.

Factors associated with development of stroke long-term after myocardial infarction: experiences from the LoWASA trial

OBJECTIVE

To describe factors associated with the development of stroke during long-term follow-up after acute myocardial infarction (AMI) in the LoWASA trial.

PATIENTS

Patients who had been hospitalized for AMI were randomized within 42 days to receive either warfarin 1.25 mg plus aspirin 75 mg daily or aspirin 75 mg alone.

DESIGN

The study was performed according to the probe design, that is open treatment and blinded end-point evaluation.

SETTING

The study was performed in 31 hospitals in Sweden. The mean follow-up time was 5.0 years with a range of 1.7-6.7 years.

RESULTS

In all, 3300 patients were randomized in the trial, of which 194 (5.9%) developed stroke (4.2% nonhaemorrhagic, 0.5% haemorrhagic and 1.3% uncertain. The following factors appeared as independent predictors for an increased risk of stroke: age, hazard ratio and 95% confidence interval (1.07; 1.05-1.08), a history of diabetes mellitus (2.4; 1.8-3.4), a history of stroke (2.3; 1.5-3.5), a history of hypertension (2.0; 1.5-2.7) and a history of smoking (1.5;1.1-2.0). Most of these factors were also predictors of a nonhaemorrhagic stroke whereas no predictor of haemorrhagic stroke was found.

CONCLUSION

Risk indicators for stroke long-term after AMI were increasing age, a history of either diabetes mellitus, stroke, hypertension or smoking.

Cardiovascular events in diabetic and nondiabetic adults with or without history of myocardial infarction

BACKGROUND

Whether diabetic patients without a history of myocardial infarction (MI) have the same risk of coronary heart disease (CHD) events as nondiabetic patients with a history of MI remains controversial. We compared risks of CHD and stroke events and mortality from cardiovascular disease (CVD) in diabetic and nondiabetic men and women with and without a history of MI.

METHODS AND RESULTS

We followed a total of 13 790 African American and white men and women ages 45 to 64 years who participated in the Atherosclerosis Risk in Communities study, beginning in 1987 to 1989. There were 634 fatal CHD or nonfatal MI events, 312 fatal or nonfatal strokes, and 358 deaths from CVD during an average of 9 years of follow-up (125 998 person-years). After adjustment for age, sex, race, Atherosclerosis Risk in Communities field center, and multiple baseline risk factors, patients who had a history of MI without diabetes at baseline had 1.9 times the risk of fatal CHD or nonfatal MI (95% CI, 1.35 to 2.56; P<0.001) compared with diabetic patients without a prior history of MI. The nondiabetic patients with MI also had 1.8 times the risk of CVD mortality compared with diabetic patients without MI (95% CI, 1.22 to 2.72; P=0.003). However, stroke risk was similar between diabetic patients without MI and nondiabetic patients with MI (RR, 1.05; 95% CI, 0.61 to 1.79; P=0.87). We also observed that nondiabetic patients with MI had a carotid artery wall thickness similar to diabetic patients without MI (P=0.77).

CONCLUSIONS

Diabetic patients without MI had lower risk of CHD events and mortality from CVD compared with nondiabetic patients with MI, but stroke risk was similar between these 2 groups.

Hypoperfusion-related cerebral ischemia and cardiac left ventricular systolic dysfunction

BACKGROUND

Cardiomyopathy and low ejection fraction (EF) are associated with cardiac thrombi and cardiogenic embolism but may also be risk factors for hypoperfusion-related cerebral ischemia (HRCI). Current stroke subtype criteria do not include an HRCI category.

METHOD

To look for evidence of HRCI, we compared mean infarct volume between serial patients with EF < or =35% and high-grade (> or = 70%) carotid stenosis and serial patients with normal EF and high-grade carotid stenosis. We matched serial stroke patients with EF < or =35% with stroke patients with normal EF and compared the number and type of ischemic lesion (symptomatic or asymptomatic) and mean infarct volume on magnetic resonance imaging. We blindly compared stroke subtype in these groups using modified Trial of ORG 10172 in Acute Stroke Treatment (TOAST) criteria, including an HRCI category.

RESULTS

In patients with carotid stenosis, ipsilateral infarct volume was greater with EF < or = 35% (74.7 mL, 95% CI, 17.3-132.1 mL) than in controls (17.1 mL, 95% Cl, 9.4-24.8 mL) (P<.05). There was no difference in the mean number of HRCI-compatible infarcts on computed tomography scan between patients with low EF and controls. Symptomatic HRCI occurred in 4 of 15 patients with low EF and in 0 of 15 controls.

CONCLUSIONS

Symptomatic HRCI occurs in patients with low EF. Severe arterial stenosis may interact with left ventricular systolic dysfunction to cause cerebral hypoperfusion. Modification of the TOAST criteria to include an HRCI subtype is feasible and HRCI should be included as a stroke subtype.

Cerebral microembolism in acute myocardial infarction

BACKGROUND AND PURPOSE

This study was undertaken to determine the frequency of cerebral microemboli (high-intensity transient signals; HITS) detected by transcranial Doppler (TCD) in patients with acute myocardial infarction (AMI) and to relate them to the various putative risk factors and clinical embolic events.

METHODS

We investigated 112 consecutive patients within 72 hours of admission to an acute coronary care unit using TCD to monitor for cerebral microemboli. Twelve patients were excluded because of failure of ultrasound insonation. All patients had 2-dimensional echocardiograms within the study period.

RESULTS

HITS were detected in 17% of patients, with significantly higher frequency in patients with reduced (<65%) left ventricular (LV) ejection fraction (P=0. 019), akinetic LV segments (P=0.002), and LV thrombus (P=0.015). A marginally significant (P=0.059) increase of HITS was found in patients with anterior AMI. Stroke was significantly more frequent in patients with cerebral microemboli (P=0.01).

CONCLUSIONS

HITS were detected in 17% of patients in spite of adequate antithrombotic therapy and were increased in patients with reduced LV function, akinetic myocardial segments, and LV thrombus. They were present in all 3 patients with stroke and may represent a predictor of clinical embolic events.

Ischemic stroke. Impact of a recent myocardial infarction

BACKGROUND AND PURPOSE

The risk of ischemic stroke is increased after a myocardial infarction. We quantified the stroke risk and evaluated ischemic stroke characteristics after an acute myocardial infarction.

METHODS

A case-control study including patients with first-ever stroke was undertaken. Cases (n=103) were recorded prospectively in the population-based Northern Sweden World Health Organization Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) study. Two controls per case with a stroke but without a recent myocardial infarction were matched for age, sex, and year of stroke onset.

RESULTS

The sudden onset of neurological symptoms (76.7% versus 54.9%, P<0.001), impairment of consciousness (35.0% versus 18.4%, P<0.01), and a progression in neurological deficits (19.4% versus 8.7%, P<0.01) were more common in cases, while the onset of stroke during sleep was rarer in cases (6.8% versus 21.4%, P<0.01). In cases and controls, the clinical subclasses of stroke were as follows: total anterior circulation infarcts, 51.5% versus 37.9% (P<0.05); partial anterior circulation infarcts, 28.2% versus 26.7% (P=NS); lacunar infarcts, 4.8% versus 27.2% (P<0.001); and posterior circulation infarcts, 15.5% versus 8.2% (P=0.051). During the first 28 days after myocardial infarction, the daily rate of stroke declined rapidly from approximately 9 to 1 stroke per 10 000 myocardial infarction patients compared with an age-adjusted average daily stroke rate of 0.14 per 10 000 in the MONICA population.

CONCLUSIONS

We conclude that the clinical characteristics of the stroke differ between patients with and without a recent myocardial infarction. The risk of a first-ever ischemic stroke is highest during the first few days after a myocardial infarction, but it then declines rapidly, and the absolute number of stroke events is low.

Prognostic significance of cerebrovascular disease in 11,526 chronic coronary artery disease patients. Bezafibrate Infarction Prevention (BIP) Study Group

Patients with chronic CAD and a history of cerebrovascular events were compared with patients without prior cerebrovascular events to assess the effect of these events on 5-year prognosis. Despite adjustment for older age and higher comorbidity among patients who had experienced a cerebrovascular event, a history of such an event was associated with an increased risk of 1.86 for total mortality.

Influence of diabetes mellitus on clinical outcome in the thrombolytic era of acute myocardial infarction. GUSTO-I Investigators. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries

OBJECTIVES

This study was undertaken to define and better understand the characteristics and outcomes of patients with diabetes treated for acute myocardial infarction with contemporary thrombolysis.

BACKGROUND

Although thrombolysis has substantially improved survival of patients with myocardial infarction, diabetes mellitus remains an independent predictor for a poor prognosis.

METHODS

We characterized the contemporary relation between diabetes and outcome after myocardial infarction treated with thrombolytic agents from a large international cohort. Of 41,021 patients randomized to receive accelerated tissue-type plasminogen activator (t-PA), streptokinase or a combination of both agents in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries study, there were 5,944 patients with diabetes and 34,888 patients without diabetes.

RESULTS

Patients with diabetes were older and more likely to be female, to present with anterior wall infarction, to receive thrombolysis later and to have triple-vessel coronary artery disease. Mortality at 30 days was highest among diabetic patients treated with insulin (12.5%) compared with non-insulin-treated diabetic (9.7%) and nondiabetic (6.2%) patients (p < 0.001). Mortality was lowest among those with diabetes receiving accelerated t-PA, which is consistent with the results of the overall patient cohort. Although stroke occurred more frequently among diabetic (1.9%) than nondiabetic patients (1.4%, p < 0.001), there was no significant difference in the rates of intracranial hemorrhage. Cardiac failure, shock, atrioventricular block and atrial flutter/ fibrillation were more common among diabetic patients. The proportion of patients undergoing revascularization was similar between patients with and without diabetes, although diabetic patients were more likely to undergo coronary artery bypass graft surgery (10.4% vs. 8.3%). Diabetes remained an independent predictor for mortality at 1-year follow-up (14.5% vs. 8.9%, p < 0.001).

CONCLUSIONS

Diabetes, alone and in association with its comorbidities, portends a substantially worse 30-day and 1-year prognosis for patients with myocardial infarction.

Relation between myocardial infarct location and stroke

OBJECTIVES

We sought to compare the likelihood of stroke in patients with anterior versus nonanterior myocardial infarction.

BACKGROUND

The association between anterior infarction and left ventricular thrombus has led to the assumption that embolization from thrombi is an important cause of stroke in patients with anterior infarction. We hypothesized that if anterior infarction is a cause of left ventricular thrombi, the number of strokes should be disproportionately higher in patients with anterior than nonanterior infarction.

METHODS

We performed a retrospective analysis of 2,466 patients randomized from day 3 to day 15 after infarction as part of a multicenter placebo-controlled study of diltiazem to prevent cardiac death or myocardial infarction. Any acute focal cerebral disorder resulting in localizing findings characterized as a stroke or transient ischemic attack was considered an event.

RESULTS

Of 91 events during a follow-up period of 12 to 52 months, 23 (3.2%) occurred in 724 patients with an anterior and 68 (3.9%) in 1,742 patients with a nonanterior myocardial infarction (relative risk 0.81; 95% confidence interval 0.51 to 1.30). Power analysis revealed that the negativity of the study was not the result of inadequate sample size. Life table analysis showed no difference in cumulative event rate (p = 0.42) according to site of infarction. Cox regression analysis showed that of 10 clinical covariates, only systolic blood pressure was predictive of stroke (p < 0.001). The use of warfarin did not contribute to the model. Finally, the addition of site of infarction (anterior vs. nonanterior) did not contribute significantly to the Cox model.

CONCLUSIONS

Although there is a significant incidence of stroke after acute myocardial infarction, there is no relation between the occurrence of stroke and site of infarction. These data do not support the presumed causal relation between anterior myocardial infarction, thrombus and stroke.