Cerebrovascular accident complicating acute myocardial infarction: incidence, clinical significance and short- and long-term mortality rates. The SPRINT Study Group

Incidence of Acute Myocardial Infarction in Patients Presenting With Cerebrovascular Accident in a Tertiary Care Centre in Eastern India

Acute myocardial infarction in individuals who have had a cerebrovascular accident or transient ischemic attack (CVA-TIA) is a medical emergency, which must be examined and treated as soon as possible. Physicians face a significant problem in managing this scenario because early treatment of one ailment would surely postpone treatment of the other. Early detection and treatment will have an impact on the patient's morbidity and mortality in the future, as well as aid in the patient's rehabilitation. On the basis of ECG alterations and cardiac biomarkers, a prospective observational study was conducted in 103 diagnosed CVA patients to investigate the incidence of myocardial infarction. Infarct and hemorrhagic CVA cases were evenly distributed. According to the age-based distribution, the highest rate of myocardial infarction (8%, 8) was observed in those aged 51-60 years. The male-to-female ratio is 1.86:1. Thirty-two patients had diabetes, among them 75% had only elevated creatine kinase MB (CKMB) with no myocardial infarction (MI), whereas 59 patients had hypertension of which 70% had only elevated CK-MB with no MI. ST-elevation myocardial infarction (STEMI) with high CKMB accounted for 14.78% (15) of the cases, but the majority (71%, 73) of the cases had elevated CKMB with no MI, and the rest presented with normal CKMB. Elevated CKMB with or without STEMI serves as a poor prognosticating factor. Therefore, these patients should be managed on a priority basis for a better outcome.

Cost-effectiveness of hypertension therapy based on 2020 International Society of Hypertension guidelines in Ethiopia from a societal perspective

Introduction

There is inadequate information on the cost-effectiveness of hypertension based on evidence-based guidelines. Therefore, this study was conducted to evaluate the cost-effectiveness of hypertension treatment based on 2020 International Society of Hypertension (ISH) guidelines from a societal perspective.

Methods

We developed a state-transition Markov model based on the cardiovascular disease policy model adapted to the Sub-Saharan African perspective to simulate costs of treated and untreated hypertension and disability-adjusted life-years (DALYs) averted by treating previously untreated adults above 30 years from a societal perspective for a lifetime.

Results

The full implementation of the ISH 2020 hypertension guidelines can prevent approximately 22,348.66 total productive life-year losses annually. The incremental net monetary benefit of treating hypertension based was $128,520,077.61 US by considering a willingness-to-pay threshold of $50,000 US per DALY averted. The incremental cost-effectiveness ratio (ICER) of treating hypertension when compared with null was $1,125.44 US per DALY averted. Treating hypertension among adults aged 40–64 years was very cost-effective 625.27 USD per DALY averted. Treating hypertensive adults aged 40–64 years with diabetes and CKD is very cost-effective in both women and men (i.e., 559.48 USD and 905.40 USD/DALY averted respectively).

Conclusion

The implementation of the ISH 2020 guidelines among hypertensive adults in Southern Ethiopia could result in $9,574,118.47 US economic savings. Controlling hypertension in all patients with or with diabetes and or CKD could be effective and cost-saving. Therefore, improving treatment coverage, blood pressure control rate, and adherence to treatment by involving all relevant stakeholders is critical to saving scarce health resources.

Bioinformatics analysis to identify potential biomarkers and therapeutic targets for ST-segment–elevation myocardial infarction-related ischemic stroke

Background

Acute myocardial infarction (AMI) is one of the major causes of mortality and disability worldwide, and ischemic stroke (IS) is a serious complication after AMI. In particular, patients with ST-segment–elevation myocardial infarction (STEMI) are more susceptible to IS. However, the interrelationship between the two disease mechanisms is not clear. Using bioinformatics tools, we investigated genes commonly expressed in patients with STEMI and IS to explore the relationship between these diseases, with the aim of uncovering the underlying biomarkers and therapeutic targets for STEMI-associated IS.

Methods

Differentially expressed genes (DEGs) related to STEMI and IS were identified through bioinformatics analysis of the Gene Expression Omnibus (GEO) datasets GSE60993 and GSE16561, respectively. Thereafter, we assessed protein-protein interaction networks, gene ontology term annotations, and pathway enrichment for DEGs using various prediction and network analysis methods. The predicted miRNAs targeting the co-expressed STEMI- and IS-related DEGs were also evaluated.

Results

We identified 210 and 29 DEGs in GSE60993 and GSE16561, respectively. CD8A, TLR2, TLR4, S100A12, and TREM1 were associated with STEMI, while the hubgenes, IL7R, CCR7, FCGR3B, CD79A, and ITK were implicated in IS. In addition, binding of the transcripts of the co-expressed DEGs MMP9, ARG1, CA4, CRISPLD2, S100A12, and GZMK to their corresponding predicted miRNAs, especially miR-654-5p, may be associated with STEMI-related IS.

Conclusions

STEMI and IS are related and MMP9, ARG1, CA4, CRISPLD2, S100A12, and GZMK genes may be underlying biomarkers involved in STEMI-related IS.

Societal economic burden of hypertension at selected hospitals in southern Ethiopia: a patient-level analysis

OBJECTIVES

There is inadequate information on the economic burden of hypertension treatment in Ethiopia. Therefore, this study was conducted to determine the societal economic burden of hypertension at selected hospitals in Southern Ethiopia.

METHODS

Prevalence-based cost of illness study from a societal perspective was conducted. Disability-adjusted life years (DALYs) were determined by the current WHO's recommended DALY valuation method. Adjustment for comorbidity and a 3% discount was done for DALYs. The data entry, processing and analysis were done by using SPSS V.21.0 and Microsoft Excel V.2013.

RESULTS

We followed a cohort of 406 adult patients with hypertension retrospectively for 10 years from September 2010 to 2020. Two hundred and fifty (61.6%) of patients were women with a mean age of 55.87±11.03 years. Less than 1 in five 75 (18.5%) of patients achieved their blood pressure control target. A total of US$64 837.48 direct cost was incurred due to hypertension. A total of 11 585 years and 579.57 years were lost due to hypertension-related premature mortality and morbidity, respectively. Treated and uncontrolled hypertension accounted for 50.83% (6027) of total years lost due to premature mortality from treated hypertension cohort. Total productivity loss due to premature mortality and morbidity was US$449 394.69. The overall economic burden of hypertension was US$514 232.16 (US$105.55 per person per month).

CONCLUSION

Societal economic burden of hypertension in Southern Ethiopia was substantial. Indirect costs accounted for more than 8 out of 10 dollars. Treated and uncontrolled hypertension took the lion's share of economic cost and productivity loss due to premature mortality and morbidity. Therefore, designing and implanting strategies for the prevention of hypertension, early screening and detection, and improving the rate of blood pressure control by involving all relevant stakeholders at all levels is critical to saving scarce health resources.

Acute Ischemic Stroke Associated with Myocardial Infarction: Challenges and Management

Acute ischemic stroke (AIS) and acute myocardial infarction (AMI) may co-occur simultaneously or in close temporal succession, with occurrence of one ischemic vascular event increasing a patient's risk for the other. Both employ time-sensitive treatments, and both benefit from expert consultation. Patients are at increased risk of stroke for up to 3 months following AMI, and aggressive treatment of AMI, including use of reperfusion therapy, decreases the risk of AIS. For patients presenting with AIS in the setting of a recent MI, treatment with alteplase, an intravenous tissue plasminogen activator, can be given, provided anterior wall myocardial involvement has been carefully evaluated. It is important for clinicians to recognize that troponin elevations can occur in the setting of AIS as well as other clinical scenarios and that this may have implications for short- and long-term mortality.

Life-Time Covariation of Major Cardiovascular Diseases: A 40-Year Longitudinal Study and Genetic Studies

BACKGROUND

It is known that certain cardiovascular diseases (CVD) are associated, like atrial fibrillation and stroke. However, for other CVDs, the links and temporal trends are less studied. In this longitudinal study, we have investigated temporal epidemiological and genetic associations between different CVDs.

METHODS

The ULSAM (Uppsala Longitudinal Study of Adult Men; 2322 men aged 50 years) has been followed for 40 years regarding 4 major CVDs (incident myocardial infarction, ischemic stroke, heart failure, and atrial fibrillation). For the genetic analyses, publicly available data were used.

RESULTS

Using multistate modeling, significant relationships were seen between pairs of all of the 4 investigated CVDs. However, the risk of obtaining one additional CVD differed substantially both between different CVDs and between their temporal order. The relationship between heart failure and atrial fibrillation showed a high risk ratio (risk ratios, 24-26) regardless of the temporal order. A consistent association was seen also for myocardial infarction and atrial fibrillation but with a lower relative risk (risk ratios, 4-5). In contrast, the risk of receiving a diagnosis of heart failure following a myocardial infarction was almost twice as high as for the reverse temporal order (risk ratios, 16 versus 9). Genetic loci linked to traditional risk factors could partly explain the observed associations between the CVDs, but pathway analyses disclosed also other pathophysiological links.

CONCLUSIONS

During 40 years, all of the 4 investigated CVDs were pairwise associated with each other regardless of the temporal order of occurrence, but the risk magnitude differed between different CVDs and their temporal order. Genetic analyses disclosed new pathophysiological links between CVDs.

Temporal Trends, Predictors, and Outcomes of Acute Ischemic Stroke in Acute Myocardial Infarction in the United States

Background

There are limited contemporary data prevalence and outcomes of acute ischemic stroke (AIS) complicating acute myocardial infarction (AMI).

Methods and Results

Adult (>18 years) AMI admissions using the National Inpatient Sample database (2000–2017) were evaluated for in‐hospital AIS. Outcomes of interest included in‐hospital mortality, hospitalization costs, length of stay, discharge disposition, and use of tracheostomy and percutaneous endoscopic gastrostomy. The discharge destination was used to classify survivors into good and poor outcomes. Of a total 11 622 528 AMI admissions, 183 896 (1.6%) had concomitant AIS. As compared with 2000, in 2017, AIS rates increased slightly among ST‐segment–elevation AMI (adjusted odds ratio, 1.10 [95% CI, 1.04–1.15]) and decreased in non–ST‐segment–elevation AMI (adjusted odds ratio, 0.47 [95% CI, 0.46–0.49]) admissions (P<0.001). Compared with those without, the AIS cohort was on average older, female, of non‐White race, with greater comorbidities, and higher rates of arrhythmias. The AMI‐AIS admissions received less frequent coronary angiography (46.9% versus 63.8%) and percutaneous coronary intervention (22.7% versus 41.8%) (P<0.001). The AIS cohort had higher in‐hospital mortality (16.4% versus 6.0%; adjusted odds ratio, 1.75 [95% CI, 1.72–1.78]; P<0.001), longer hospital length of stay, higher hospitalization costs, greater use of tracheostomy and percutaneous endoscopic gastrostomy, and less frequent discharges to home (all P<0.001). Among AMI‐AIS survivors (N=153 318), 57.3% had a poor functional outcome at discharge with relatively stable temporal trends.

Conclusions

AIS is associated with significantly higher in‐hospital mortality and poor functional outcomes in AMI admissions.

Stroke Risk in Patients With Reduced Ejection Fraction After Myocardial Infarction Without Atrial Fibrillation

BACKGROUND

Stroke can occur after myocardial infarction (MI) in the absence of atrial fibrillation (AF).

OBJECTIVES

This study sought to identify risk factors (excluding AF) for the occurrence of stroke and to develop a calibrated and validated stroke risk score in patients with MI and heart failure (HF) and/or systolic dysfunction.

METHODS

The datasets included in this pooling initiative were derived from 4 trials: CAPRICORN (Effect of Carvedilol on Outcome After Myocardial Infarction in Patients With Left Ventricular Dysfunction), OPTIMAAL (Optimal Trial in Myocardial Infarction With Angiotensin II Antagonist Losartan), VALIANT (Valsartan in Acute Myocardial Infarction Trial), and EPHESUS (Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study); EPHESUS was used for external validation. A total of 22,904 patients without AF or oral anticoagulation were included in this analysis. The primary outcome was stroke, and death was treated as a "competing risk."

RESULTS

During a median follow-up of 1.9 years (interquartile range: 1.3 to 2.7 years), 660 (2.9%) patients had a stroke. These patients were older, more often female, smokers, and hypertensive; they had a higher Killip class; a lower estimated glomerular filtration rate; and a higher proportion of MI, HF, diabetes, and stroke histories. The final stroke risk model retained older age, Killip class 3 or 4, estimated glomerular filtration rate ≤45 ml/min/1.73 m², hypertension history, and previous stroke. The models were well calibrated and showed moderate to good discrimination (C-index = 0.67). The observed 3-year event rates increased steeply for each sextile of the stroke risk score (1.8%, 2.9%, 4.1%, 5.6%, 8.3%, and 10.9%, respectively) and were in agreement with the expected event rates.

CONCLUSIONS

Readily accessible risk factors associated with the occurrence of stroke were identified and incorporated in an easy-to-use risk score. This score may help in the identification of patients with MI and HF and a high risk for stroke despite their not presenting with AF.

Twenty-Five-Year (1986-2011) Trends in the Incidence and Death Rates of Stroke Complicating Acute Myocardial Infarction

BACKGROUND

The occurrence of a stroke after an acute myocardial infarction is associated with increased morbidity and mortality rates. However, limited data are available, particularly from a population-based perspective, about recent trends in the incidence and mortality rates associated with stroke complicating an acute myocardial infarction. The purpose of this study was to examine 25-year trends (1986-2011) in the incidence and in-hospital mortality rates of initial episodes of stroke complicating acute myocardial infarction.

METHODS

The study population consisted of 11,436 adults hospitalized with acute myocardial infarction at all 11 medical centers in central Massachusetts on a biennial basis between 1986 and 2011.

RESULTS

In this study cohort, 159 patients (1.4%) experienced an acute first-ever stroke during hospitalization for acute myocardial infarction. The proportion of patients with acute myocardial infarction who developed a stroke increased through the 1990s but decreased slightly thereafter. Compared with patients who did not experience a stroke, those who experienced a stroke were significantly older, were more likely to be female, had a previous acute myocardial infarction, had a significant burden of comorbidities, and were more likely to have died (32.1% vs 10.8%) during their index hospitalization. Patients who developed a first stroke in the most recent study years (2003-2011) were more likely to have died during hospitalization than those hospitalized during earlier study years.

CONCLUSIONS

Although the incidence rates of acute stroke complicating acute myocardial infarction remained relatively stable during the years under study, the in-hospital mortality rates of those experiencing a stroke have not decreased.

Cost-effectiveness and population impact of statins for primary prevention in adults aged 75 years or older in the United States

BACKGROUND

Evidence to guide primary prevention in adults aged 75 years or older is limited.

OBJECTIVE

To project the population impact and cost-effectiveness of statin therapy in adults aged 75 years or older.

DESIGN

Forecasting study using the Cardiovascular Disease Policy Model, a Markov model.

DATA SOURCES

Trial, cohort, and nationally representative data sources.

TARGET POPULATION

U.S. adults aged 75 to 94 years.

TIME HORIZON

10 years.

PERSPECTIVE

Health care system.

INTERVENTION

Statins for primary prevention based on low-density lipoprotein cholesterol threshold of 4.91 mmol/L (190 mg/dL), 4.14 mmol/L (160 mg/dL), or 3.36 mmol/L (130 mg/dL); presence of diabetes; or 10-year risk score of at least 7.5%.

OUTCOME MEASURES

Myocardial infarction (MI), coronary heart disease (CHD) death, disability-adjusted life-years, and costs.

RESULTS OF BASE-CASE ANALYSIS

All adults aged 75 years or older in the National Health and Nutrition Examination Survey have a 10-year risk score greater than 7.5%. If statins had no effect on functional limitation or cognitive impairment, all primary prevention strategies would prevent MIs and CHD deaths and be cost-effective. Treatment of all adults aged 75 to 94 years would result in 8 million additional users and prevent 105 000 (4.3%) incident MIs and 68 000 (2.3%) CHD deaths at an incremental cost per disability-adjusted life-year of $25 200.

RESULTS OF SENSITIVITY ANALYSIS

An increased relative risk for functional limitation or mild cognitive impairment of 1.10 to 1.29 could offset the cardiovascular benefits.

LIMITATION

Limited trial evidence targeting primary prevention in adults aged 75 years or older.

CONCLUSION

At effectiveness similar to that in trials, statins are projected to be cost-effective for primary prevention; however, even a small increase in geriatric-specific adverse effects could offset the cardiovascular benefit. Improved data on the potential benefits and harms of statins are needed to inform decision making.

PRIMARY FUNDING SOURCE

American Heart Association Western States Affiliate, National Institute on Aging, and the National Institute for Diabetes on Digestive and Kidney Diseases.

Patient characteristics and comorbidities associated with cerebrovascular accident following acute myocardial infarction in the United States

BACKGROUND

Although cerebrovascular accident (CVA) is a relatively infrequent complication of acute myocardial infarction (AMI), the occurrence of CVA in patients with AMI is associated with increased morbidity and mortality. We wanted to assess post-AMI CVA rate in the United States and identify the associated patient characteristics, comorbidities, type of AMI, and utilization of invasive procedures.

METHODS

This is an observational study from the Nationwide Inpatient Sample, 2006-2008. Using multivariate regression models, we assessed predictive risk factors for post-AMI CVA among patients admitted for AMI.

RESULTS

Among the 1,924,413 patients admitted for AMI, the overall rate of CVA was 2% (ischemic stroke: 1.47%, transient ischemic attack [TIA]: 0.35% and hemorrhagic stroke: 0.21%). In this sample of AMI patient, higher incidence of CVA was associated with: CHF (adjusted odds ratio [AOR] 1.71; 95% confidence interval [CI], 1.58-1.84,), age over 65 AOR, 1.65; 95% CI, 1.60-1.70, alcohol abuse AOR, 1.60; 95% CI, 1.49-1.73, cocaine use AOR, 1.48; 95% CI, 1.29-1.70, atrial fibrillation AOR, 1.43; 95% CI, 1.39-1.46, Black race AOR, 1.35; 95% CI, 1.30-1.40, female gender AOR, 1.32; 95% CI, 1.29-1.35, peripheral vascular disease [PVD] AOR, 1.26; 95% CI, 1.22-1.30, coronary artery bypass graft (CABG) AOR, 1.22; 95% CI, 1.17-1.27, P<0.0001, STEMI AOR, 1.17; 95% CI, 1.14-1.20 and teaching hospitals AOR, 1.09; 95% CI, 1.06-1.12.

CONCLUSION

Female gender, older age (age≥65), black ethnicity, comorbidities including CHF, PVD, atrial fibrillation as well as STEMI and undergoing CABG were associated with the highest risk of CVA post-AMI.

Recurrent myocardial infarction after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction

The determinants and prognostic value of recurrent myocardial infarction (MI) in a contemporary cohort of ST-segment elevation MI patients treated with primary percutaneous coronary intervention (PPCI) and stenting are currently unknown. We investigated the predictors and prognostic impact of recurrent MI on subsequent clinical outcome in 1,700 ST-segment elevation MI patients treated with PPCI and stenting between January 1, 2003, and July 31, 2008. Two hundred forty patients had a recurrent MI during a median follow-up of 4 years and 7 months (Kaplan Meier estimate 21.2%). By multivariable analysis, recurrent MI was associated with a higher risk of subsequent cardiac mortality (hazard ratio [HR] 6.86, 95% confidence interval [CI] 4.24 to 8.72), noncardiac mortality (HR 2.02, 95% CI 1.10 to 3.69), stroke (HR 3.68, 95% CI 2.02 to 6.72), and Global Use of Strategies to Open Occluded Coronary Arteries criteria severe or moderate bleeding (HR 3.17, 95% CI 1.79 to 5.60). Early recurrent MI (within 1 day of the initial PPCI) was associated with higher unadjusted cardiac mortality rates (64.4%) compared with recurrent MIs occurring ≥1 day after PPCI. However, after multivariable adjustment, late recurrent MI (occurring >1 year after PPCI) was associated with the highest risk of subsequent cardiac mortality (HR 7.98, 95% CI 5.05 to 12.6). The risk of cardiac death was irrespective of the presence of persistent ST-segment elevation during the recurrent MI. In conclusion, recurrent MI after PPCI remains a relatively common complication in contemporary practice and confers a significantly increased risk of death, stroke, and bleeding.

Neurologic complications of myocardial infarction

Cardiac disease, in particular coronary artery disease, is the leading cause of mortality in developed nations. Strokes can complicate cardiac disease - either as result of left ventricular dysfunction and associated thrombus formation or of therapy for the cardiac disease. Antiplatelet drugs and anticoagulants routinely used to treat cardiac disease increase the risk for hemorrhagic stroke.

Immediate and one-year outcome of patients presenting with acute coronary syndrome complicated by stroke: findings from the 2nd Gulf Registry of Acute Coronary Events (Gulf RACE-2)

Background

Stroke is a potential complication of acute coronary syndrome (ACS). The aim of this study was to identify the prevalence, risk factors predisposing to stroke, in-hospital and 1-year mortality among patients presenting with ACS in the Middle East.

Methods

For a period of 9 months in 2008 to 2009, 7,930 consecutive ACS patients were enrolled from 65 hospitals in 6 Middle East countries.

Results

The prevalence of in-hospital stroke following ACS was 0.70%. Most cases were ST segment elevation MI-related (STEMI) and ischemic stroke in nature. Patients with in-hospital stroke were 5 years older than patients without stroke and were more likely to have hypertension (66% vs. 47.6%, P = 0.001). There were no differences between the two groups in regards to gender, other cardiovascular risk factors, or prior cardiovascular disease. Patients with stroke were more likely to present with atypical symptoms, advanced Killip class and less likely to be treated with evidence-based therapies. Independent predictors of stroke were hypertension, advanced killip class, ACS type –STEMI and cardiogenic shock. Stroke was associated with increased risk of in-hospital (39.3% vs. 4.3%) and one-year mortality (52% vs. 12.3%).

Conclusion

There is low incidence of in-hospital stroke in Middle-Eastern patients presenting with ACS but with very high in-hospital and one-year mortality rates. Stroke patients were less likely to be appropriately treated with evidence-based therapy. Future work should be focused on reducing the risk and improving the outcome of this devastating complication.

Antithrombotic medication for cardioembolic stroke prevention

Embolism of cardiac origin accounts for about 20% of ischemic strokes. Nonvalvular atrial fibrillation is the most frequent cause of cardioembolic stroke. Approximately 1% of population is affected by atrial fibrillation, and its prevalence is growing with ageing in the modern world. Strokes due to cardioembolism are in general severe and prone to early recurrence and have a higher long-term risk of recurrence and mortality. Despite its enormous preventive potential, continuous oral anticoagulation is prescribed for less than half of patients with atrial fibrillation who have risk factors for cardioembolism and no contraindications for anticoagulation. Available evidence does not support routine immediate anticoagulation of acute cardioembolic stroke. Anticoagulation therapy's associated risk of hemorrhage and monitoring requirements have encouraged the investigation of alternative therapies for individuals with atrial fibrillation. New anticoagulants being tested for prevention of stroke are low-molecular-weight heparins (LMWH), unfractionated heparin, factor Xa inhibitors, or direct thrombin inhibitors like dabigatran etexilate and rivaroxaban. The later exhibit stable pharmacokinetics obviating the need for coagulation monitoring or dose titration, and they lack clinically significant food or drug interaction. Moreover, they offer another potential that includes fixed dosing, oral administration, and rapid onset of action. There are several concerns regarding potential harm, including an increased risk for hepatotoxicity, clinically significant bleeding, and acute coronary events. Therefore, additional trials and postmarketing surveillance will be needed.

Acute Cerebral Infarction Following Intravenous Glycoprotein IIb/IIIa Inhibitor for Acute Myocardial Infarction

Stroke is a rare but serious complication of acute myocardial infarction (AMI). Currently, glycoprotein (GP) IIb/IIIa inhibitor is used in clinical practice for acute coronary syndromes and percutaneous coronary interventions (PCIs). The incidence of stroke in patients receiving GP IIb/IIIa inhibitor during PCIs is very low. We report the case of a 47-year-old man who presented with AMI and suffered an acute cerebral infarction after infusion of a GP IIb/IIIa inhibitor following primary PCI.

Evaluating the role of elevated levels of troponin in acute ischemic stroke

Ischemic heart disease and cerebrovascular diseases may coexist in the same patient, and similar risk factors are shared. However, for several years, experimental and observational data have incessantly indicated that neurologically induced myocardial injury exists. This leaves the clinician with a diagnostic dilemma of how to distinguish between neurologically induced myocardial injury and myocardial infarction prior to the stroke. Since various alterations of the ECG have also been reported in this patient category, it has been suggested that elevated troponin levels are somehow neurologically mediated, thus not resulting from direct cardiac release. This review focuses on the available studies that systematically measured troponin in patients with acute ischemic stroke in order to properly interpret troponin elevations in these patients.

Circadian, day-of-week, and age patterns of the occurrence of acute coronary syndrome in Beijing's emergency medical services system

Background

Previous in-hospital studies suggest that there are significant circadian rhythms associated with the incidence of acute coronary syndromes (ACSs). No study to date has examined the presentation of ACS in the prehospital setting. Our goal was to examine circadian, day-of-week, and age patterns of occurrence in ACS in a large, urban emergency medical services (EMS) system.

Methods

We retrospectively reviewed the electronic prehospital medical records from the Beijing's EMS system spanning August 1, 2005, to July 31, 2007. Data were analyzed by hour of the day and day of the week. χ² tests were performed to compare the difference.

Results

Seven thousand thirty-two cases of ACS were identified by the EMS system physicians during the 2-year study period, including 536 cases of acute myocardial infarction. A significant variation of circadian distribution of ACS was observed in both 24-hour (P < .001) and 2-hour (P < .001) interval time course. Two peaks were observed in the morning from 0800 to 1000 and approaching midnight from 2200 to 2400. Increases of 50% and 60.8% in the morning and evening peaks were found, respectively, when compared with the early morning baseline (nadir). No significant difference was found among the accumulated cases in 2 years on each day in a week (P = .203).

Conclusions

Our study shows that, in the Beijing metropolitan area, the presentation of ACS has significant circadian rhythm characterized by 2 peaks within 24 hours, the morning peak is 0800 to 1000, and the late evening peak is 2200 to 2400. No significant weekly rhythm was observed in the present study.

Selective risk factors profiles and outcomes among patients with stroke and history of prior myocardial infarction. The European Community Stroke Project

BACKGROUND AND OBJECTIVE

Previous myocardial infarction (MI) has been linked with poorer stroke outcome. Whether this depends on a greater stroke severity is still uncertain. The aim of the study was to assess the effect of previous MI on characteristics and outcome of stroke in a large hospital cohort of patients.

METHODS

In a European Union Concerted Action, patients hospitalized for first-in-a-lifetime stroke were assessed for demographics, risk factors, clinical presentation, and 3-month survival and handicap.

RESULTS

Out of 4190 study patients, 460 (11%) reported a history of MI. Compared with patients without previous MI, those with MI were significantly older, more often males, smokers, alcohol consumers, and with a more severe pre-stroke level of handicap. They had more frequently atrial fibrillation and a history of transient ischemic attack. The acute neurological state and the 28-day mortality did not differ between the two groups. At 3 months, death or severe handicap were more frequent in the MI group (28.3% vs. 21.7%, P=0.001; 74.8% vs. 65.8%, P=0.008). Controlling by logistic regression analysis for age, sex, vascular risk factors, comorbidities, prior to stroke therapy, pre-stroke level of handicap, and clinical acute phase variables, prior MI remained an independent predictor of 3-month death (OR 1.30; 95% CI, 1.02-1.66) and 3-month handicap (OR 1.46; 95% CI, 1.01-2.11).

CONCLUSIONS

Previous MI has no impact on clinical severity of acute stroke, but significantly affects 3-month outcome in terms of handicap and mortality.

Causes of Mortality on a University Hospital Neurology Service

BACKGROUND

The mortality rate for all patients cared for by inpatient neurology services has not been described.

METHODS

Quality assurance case discussions of all patients (n = 6012) admitted to a neurology service from 1996 to 2003 were reviewed to determine frequency and causes of mortality. All cases of mortality were reviewed in detail.

RESULTS

The majority of patients (98%) survived their admission; 118 patients died. In 95/118 cases, care had been withdrawn at the time of death. In 11 cases, adverse events occurred during the patients' hospital stay and may have impacted outcome. Few patients (18%) had clear advance directives.

CONCLUSION

Most mortality in this acute care neurology setting occurs in the course of stroke, epilepsy, or complicated tumor management and is managed through withdrawal of care with family participation.

Inhibition of phospholipase C-γ1augments the decrease in cardiomyocyte viability by H2O2

The present study was conducted to examine the role of a major cardiac phospholipase C (PLC) isozyme, PLC-γ1, in cardiomyocytes during oxidative stress. Left ventricular cardiomyocytes were isolated by collagenase digestion from adult male Sprague-Dawley rats (250–300 g) and treated with 20, 50, and 100 μM H2O2for 15 min. A concentration-dependent (up to 50 μM) increase in the mRNA level and membrane protein content of PLC-γ1was observed with H2O2treatment. Furthermore, PLC-γ1was activated in response to H2O2, as revealed by an increase in the phosphorylation of its tyrosine residues. There was a marked increase in the phosphorylation of the antiapoptotic protein Bcl-2 by H2O2; this change was attenuated by a PLC inhibitor, U-73122. Although both protein kinase C (PKC)-δ and -ε protein contents were increased in the cardiomyocyte membrane fraction in response to H2O2, PKC-ε activation, unlike PKC-δ, was attenuated by U-73122 (2 μM). Inhibition of PKC-ε with inhibitory peptide (0.1 μM) prevented Bcl-2 phosphorylation. Moreover, different concentrations (0.05, 0.1, and 0.2 μM) of this peptide augmented the decrease in cardiomyocyte viability in response to H2O2. In addition, a decrease in cardiomyocyte viability, as assessed by trypan blue exclusion, due to H2O2was also seen when cells were pretreated with U-73122 and was as a result of increased apoptosis. It is therefore suggested that PLC-γ1may play a role in cardiomyocyte survival during oxidative stress via PKC-ε and phosphorylation of Bcl-2.

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.

Pharmacokinetic and pharmacodynamic issues in the treatment of bacterial infectious diseases

This review outlines some of the many factors a clinician must consider when selecting an antimicrobial dosing regimen for the treatment of infection. Integration of the principles of antimicrobial pharmacology and the pharmacokinetic parameters of an individual patient provides the most comprehensive assessment of the interactions between pathogen, host, and antibiotic. For each class of agent, appreciation of the different approaches to maximize microbial killing will allow for optimal clinical efficacy and reduction in risk of development of resistance while avoiding excessive exposure and minimizing risk of toxicity. Disease states with special considerations for antimicrobial use are reviewed, as are situations in which pathophysiologic changes may alter the pharmacokinetic handling of antimicrobial agents.

Pharmacodynamics of the new des-f(6)-quinolone garenoxacin in a murine thigh infection model

Garenoxacin is a new des-F(6)-quinolone with broad-spectrum activity against both gram-positive cocci and gram-negative bacilli. We used the neutropenic murine thigh infection model to characterize the time course of antimicrobial activity of garenoxacin and determine which pharmacokinetic-pharmacodynamic (PK-PD) parameter best correlated with efficacy. Serum drug levels following three fourfold-escalating single-dose levels of garenoxacin were measured by microbiologic assay. In vivo postantibiotic effects (PAEs) were determined after doses of 16 and 64 mg/kg of body weight. Mice had 10(6.5) to 10(6.7) CFU of Streptococcus pneumoniae strain ATCC 10813 or Staphylococcus aureus strain ATCC 33591 per thigh when they were treated for 24 h with garenoxacin at a dose of 4 to 128 mg/kg/day fractionated for 3-, 6-, 12-, and 24-hour dosing regimens. Nonlinear regression analysis was used to determine which PK-PD parameter best correlated with the measurement of CFU/thigh at 24 h. Pharmacokinetic studies yielded peak/dose values of 0.2 to 0.3, area under the concentration-time curve (AUC)/dose values of 0.1 to 0.5, and half-lives of 0.7 to 1.6 h. Garenoxacin produced in vivo PAEs of 1.4 to 8.2 h with S. pneumoniae ATCC 10813, 7.6 to >12.4 h with S. aureus ATCC 25923, and 0 to 1.5 h with Klebsiella pneumoniae ATCC 43816. The 24-h AUC/MIC ratio was the PK-PD parameter that best correlated with efficacy (R2=71 to 90% for the two organisms compared with 43 to 56% for the peak/MIC ratio and 47 to 75% for percent time above the MIC [% T>MIC]). In subsequent studies we used the neutropenic murine thigh infection model to determine if the magnitude of the AUC/MIC ratio needed for efficacy of garenoxacin varied among pathogens (including resistant strains). Mice had 10(5.9) to 10(7.2) CFU of 6 strains of S. aureus (2 methicillin resistant), 11 strains of S. pneumoniae (5 penicillin susceptible, 1 penicillin intermediate, and 5 penicillin resistant, and of the resistant strains, 3 were also ciprofloxacin resistant), and 4 gram-negative strains per thigh when treated for 24 h with 1 to 64 mg of garenoxacin per kg every 12 h. A sigmoid dose-response model was used to estimate the doses (mg/kg/24 h) required to achieve a net bacteriostatic effect over 24 h. MICs ranged from 0.008 to 4 microg/ml. The free drug 24-h AUC/MIC ratios for each static dose (2.8 to 128 mg/kg/day) varied from 8.2 to 145. The mean 24-h AUC/MIC ratios +/- standard deviations for S. pneumoniae, S. aureus, and gram-negative strains were 33 +/- 18, 81 +/- 37, and 33 +/- 30, respectively. Methicillin, penicillin, or ciprofloxacin resistance did not alter the magnitude of the AUC/MIC ratio required for efficacy.

Ciprofloxacin in polyethylene glycol-coated liposomes: efficacy in rat models of acute or chronic Pseudomonas aeruginosa infection

In a previous study in experimental Klebsiella pneumoniae pneumonia, the therapeutic potential of ciprofloxacin was significantly improved by encapsulation in polyethylene glycol-coated ("pegylated") long-circulating (STEALTH) liposomes. Pegylated liposomal ciprofloxacin in high doses was nontoxic and resulted in relatively high and sustained ciprofloxacin concentrations in blood and tissues, and hence an increase in the area under the plasma concentration-time curve (AUC). These data correspond to data from animal and clinical studies showing that for fluoroquinolones the AUC/MIC ratio is associated with favorable outcome in serious infections. Clinical failures and the development of resistance are observed for marginally susceptible organisms like Pseudomonas aeruginosa and for which sufficient AUC/MIC ratios cannot be achieved. In the present study the therapeutic efficacy of pegylated liposomal ciprofloxacin was investigated in two rat models of Pseudomonas aeruginosa pneumonia. In the acute model pneumonia developed progressively, resulting in a rapid onset of septicemia and a high mortality rate. Ciprofloxacin twice daily for 7 days was not effective at doses at or below the maximum tolerated dose (MTD). However, pegylated liposomal ciprofloxacin either at high dosage or given at low dosage in combination with free ciprofloxacin on the first day of treatment was fully effective (100% survival). Obviously, prolonged concentrations of ciprofloxacin in blood prevented death of the animals due to early-stage septicemia in this acute infection. However, bacterial eradication from the left lung was not effected. In the chronic model, pneumonia was characterized by bacterial persistence in the lung without bacteremia, and no signs of morbidity or mortality were observed. Ciprofloxacin administered for 7 days at the MTD twice daily resulted in killing of more than 99% of bacteria in the lung; this result can also be achieved with pegylated liposomal ciprofloxacin given once daily. Complete bacterial eradication is never observed.

Pharmacodynamics of the new fluoroquinolone gatifloxacin in murine thigh and lung infection models

Gatifloxacin is a new 8-methoxy fluoroquinolone with enhanced activity against gram-positive cocci. We used the neutropenic murine thigh infection model to characterize the time course of antimicrobial activity of gatifloxacin and determine which pharmacokinetic (PK)-pharmacodynamic (PD) parameter best correlated with efficacy. The thighs of mice were infected with 10(6.5) to 10(7.4) CFU of strains of Staphylococcus aureus, Streptococcus pneumoniae, or Escherichia coli, and the mice were then treated for 24 h with 0.29 to 600 mg of gatifloxacin per kg of body weight per day, with the dose fractionated for dosing every 3, 6, 12, and 24 h. Levels in serum were measured by microbiologic assay. In vivo postantibiotic effects (PAEs) were calculated from serial values of the log(10) numbers of CFU per thigh 2 to 4 h after the administration of doses of 8 and 32 mg/kg. Nonlinear regression analysis was used to determine which PK-PD parameter best correlated with the numbers of CFU per thigh at 24 h. Pharmacokinetic studies revealed peak/dose values of 0.23 to 0.32, area under the concentration-time curve (AUC)/dose values of 0.47 to 0.62, and half-lives of 0.6 to 1.1 h. Gatifloxacin produced in vivo PAEs of 0.2 to 3.1 h for S. pneumoniae and 0.4 to 2.3 h for S. aureus. The 24-h AUC/MIC was the PK-PD parameter that best correlated with efficacy (R(2) = 90 to 94% for the three organisms, whereas R(2) = 70 to 81% for peak level/MIC and R(2) = 48 to 73% for the time that the concentration in serum was greater than the MIC). There was some reduced activity when dosing every 24 h was used due to the short half-life of gatifloxacin in mice. In subsequent studies we used the neutropenic and nonneutropenic murine thigh and lung infection models to determine if the magnitude of the AUC/MIC needed for the efficacy of gatifloxacin varied among pathogens (including resistant strains) and infection sites. The mice were infected with 10(6.5) to 10(7.4) CFU of four isolates of S. aureus (one methicillin resistant) per thigh, nine isolates of S. pneumoniae (two penicillin intermediate, four penicillin resistant, and two ciprofloxacin resistant) per thigh, four isolates of the family Enterobacteriaceae per thigh, a single isolate of Pseudomonas aeruginosa per thigh, and 10(8.3) CFU of Klebsiella pneumoniae per lung. The mice were then treated for 24 h with 0.29 to 600 mg of gatifloxacin per kg every 6 or 12 h. A sigmoid dose-response model was used to estimate the dose (in milligrams per kilogram per 24 h) required to achieve a net bacteriostatic effect over 24 h. MICs ranged from 0.015 to 8 microg/ml. The 24-h AUC/MICs for each static dose (1.7 to 592) varied from 16 to 72. Mean +/- standard deviation 24-h AUC/MICs for isolates of the family Enterobacteriaceae, S. pneumoniae, and S. aureus were 41 +/- 21, 52 +/- 20, and 36 +/- 9, respectively. Methicillin, penicillin, or ciprofloxacin resistance did not alter the magnitude of the AUC/MIC required for efficacy. The 24-h AUC/MICs required to achieve bacteriostatic effects against K. pneumoniae were quite similar in the thigh and lung (70 versus 56 in neutropenic mice and 32 versus 43 in nonneutropenic mice, respectively). The magnitude of the 24-h AUC/MIC of gatifloxacin required for efficacy against multiple pathogens varied only fourfold and was not significantly altered by drug resistance or site of infection.

Embolization of calcific thrombi after tissue plasminogen activator treatment

BACKGROUND AND PURPOSE

Embolic stroke has been reported after thrombolysis in cardiac patients but has not yet been documented after thrombolytic therapy for acute ischemic stroke.

DESCRIPTION OF CASES

Patient 1 had a calcific embolus in the right M1 region on head computed tomography (CT) scan when treated with tissue plasminogen activator (tPA). Repeat imaging within hours showed distal migration of calcific fragments into the M2 region. Patient 2 had a calcific embolus in the right M1 region, as well as distal calcific emboli in multiple vascular distributions on initial head CT scan. She was treated with intravenous tPA but became unresponsive within 2 hours. Repeat imaging showed new calcium-density signal in the basilar artery.

CONCLUSIONS

We present 2 cases of radiographically evident, calcific embolization after tPA therapy for acute ischemic stroke. Emboli with a calcific component may lyse with tPA, but such patients should be carefully monitored for distal or recurrent embolization.

Long-term prevention of ischaemic stroke and stroke recurrence

Stroke is the third most important cause of mortality, but the leading cause of severe handicap, dependency, and loss of social competence. Because of the high recurrence rate, active secondary prevention is mandatory once a stroke has occurred. Secondary prevention of stroke implies the primary prevention of cardiovascular disorders as well. Among the modifiable risk factors hypertension is worst and should be normalized according to recent WHO criteria, also in the elderly. Smoking is another major risk factor and hard to delete. Diabetes mellitus and hyperlipidaemia are also important risk factors and should be treated consequently by diet and medication. Moderate alcohol intake, normalization of body weight and regular physical activity also contribute considerably to prevention of stroke. Whether hyperhomocysteinaemia should be normalized has not yet been clarified. Cardiovascular disorders are an important source of ischemic strokes, particularly atrial fibrillation. Low dose anticoagulation can dramatically reduce stroke risk. Carotid endarterectomy in symptomatic stenoses is the most expensive means of stroke prevention. In less severe stenoses, or ICA occlusions, antiplatelet agents are the treatment of choice. Composite drugs with ASS and other antiplatelet agents seem to be superior to either compound alone. Dissections of the cervical arteries should not be operated on but may be treated by anticoagulation or antiplatelet agents in the acute and subacute phase. The potency of a consequent and comprehensive stroke prevention in preventing disability and death is much greater than any sophisticated acute stroke treatment.

CME Paper: Acute Myocardial Infarction in the Elderly

Up to half of admissions with myocardial infarction are over 70 years of age. Mortality in this age group is higher than in younger age groups. However, elderly patients are less likely to be managed in an acute coronary care setting. Low dose aspirin should be given to all elderly patients with myocardial infarction. Thrombolytic agents have the greatest effect in the elderly even though they give an increased risk of hemorrhagic stroke. They are underused in the elderly with myocardial infarction for a number of reasons. Ã -Blockers reduce mortality post infarction and ACE inhibitors improve morbidity and mortality rates in those with evidence of heart failure post infarction. Amiodarone may also be of use as an antiarrhythmic in the post infarction period. (c) 2000 by CVRR, Inc.

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.

Coronary heart disease. Stable and unstable syndromes

CHD in the elderly population will continue to be a source of major concern because of the increasing costs entailed and uncertainties about how the widespread array of diagnostic and therapeutic interventions, often expensive and sometimes hazardous, should be applied. Financial, political, and health policy decisions will continue to occupy much attention, but it is likely that philosophic considerations about aging and death, both from the individual and the societal perspective, will be of paramount importance of deciding how the substantial resources available to the elderly will be used. Randomized, controlled trials are unlikely to play a major role in resolution of management dilemmas in the elderly because of the extraordinary heterogeneity in this population. Registries (databases) involving carefully prospectively collected key variables are likely to be a more effective approach. Critical characterization of complications of procedures, adverse drug reactions, and collection of follow-up data on functional status are among the critical questions, and these can be answered by registry studies. Algorithms and clinical rules developed in younger cohorts are not directly transferable to the elderly cardiovascular patients, further emphasizing the need for prospectively collected, syndrome-specific data. Treatments convincingly demonstrated to reduce mortality in absolute terms more in the elderly than in the young are underused. The heterogeneity of aging emphasizes the wide variability in patients' ability to withstand the stress of procedures and complications of disease and makes clear the need to consider physiologic reserve and biologic age rather than chronology. With better characterization of biologic age and physiologic reserve, more precise estimates of outcomes of therapies and interventions can be made, and patients can be given better information and with their families have more realistic expectations. Better-informed decisions will result. Biologic age will be multifactorial, involving cognitive, emotional, physical, and nutritional attributes as well as specific organ function (lung, kidney, liver) because no single feature can characterize the total elderly patient. The concept of competing risks among the cardiovascular disease being treated, comorbidity, risks of study, and life expectancy will evolve because even the most successful therapy will have limited effect on longevity in the very old. Although important research at the cellular and molecular level will characterize and provide better understanding of the aging process, it is not likely that this basic information will be immediately useful in the management of the large number of elderly patients with major cardiovascular disease. Preventive measures, including physical exercise, mental stimulation, avoidance of depression, good nutrition, and abstinence from tobacco use, are useful approaches to postpone or ameliorate the consequences of aging and allow patients to tolerate cardiovascular diseases better when they become manifest.

HMG-CoA reductase inhibitor therapy and stroke risk reduction: an analysis of clinical trials data

Although associations of cholesterol and coronary heart disease (CHD) are well accepted, the association between cholesterol and stroke has been a subject of some confusion. Epidemiologic evidence suggests no association between plasma concentrations of cholesterol and stroke, and earlier clinical trials were also negative. Two early meta-analyses of clinical trials designed to evaluate the effects of cholesterol lowering on CHD concluded that cholesterol lowering had no effect. More recently newer, more potent and better tolerated agents (HMG-CoA reductase inhibitors, reductase inhibitors) have become available and have been tested for their efficacy in reducing cholesterol and CHD in both primary prevention and secondary prevention trials. Meta-analyses of these trials, in contrast to the earlier trials, reveal a powerful statistically significant effect to reduce stroke as well as CHD in secondary prevention (30%); the direction of the effect is the same in trials of primary prevention or trials that randomized patients with and without CHD (mixed primary and secondary prevention trials) where the risk reductions for stroke, although not reaching statistical significance are 11 and 30%, respectively. An important difference in the newer analysis is the availability of several trials of secondary prevention in which low density lipoprotein cholesterol was lowered 25-30% and in which CHD event reduction was similarly reduced by 30%. Mechanisms for stroke reduction likely involve retardation of plaque progression in the intracranial and extracranial carotid arteries, plaque stabilization, and, in addition, stroke may be reduced partly as a consequence of CHD reduction.

Incidence and mortality from early stroke associated with acute myocardial infarction in the prethrombolytic and thrombolytic eras. Secondary Prevention Reinfarction Israeli Nifedipine Trial (SPRINT) and Israeli Thrombolytic Survey Groups

OBJECTIVES

This study sought to compare the incidence of early cerebrovascular events and subsequent mortality in two cohorts of consecutive patients with acute myocardial infarction (AMI), admitted to coronary care units (CCUs) in Israel, in the prethrombolytic and thrombolytic eras.

BACKGROUND

During the past decade, substantial changes have occurred in the medical treatment of AMI, and important new therapies have been introduced that could all affect stroke risk and type by diverse mechanisms. Yet the overall impact of these new therapeutic modalities on the incidence of stroke complicating AMI is not clear.

METHODS

We compared the incidence and mortality rates of cerebrovascular events complicating AMI within CCUs among 5,839 consecutive patients admitted in the period 1981 to 1983 versus 2,012 patients from two prospective nationwide surveys conducted in all CCUs operating in Israel in 1992 and 1994.

RESULTS

The demographic and clinical characteristics of patients with AMI in both periods were comparable. Patients admitted in the period 1981 to 1983 did not receive thrombolysis and reperfusion therapy; those admitted in 1992 and 1994 received thrombolysis (45%) and coronary angioplasty or coronary artery bypass graft surgery (14%), and antiplatelet and anticoagulant treatments were more frequently used. The incidence of early cerebrovascular events was 0.74% (43 of 5,839) in 1981 to 1983 versus 0.75% (15 of 2,012) in the 1992 to 1994 cohort. Patients with an AMI who experienced a cerebrovascular event were somewhat older in both groups and had a high rate of previous cerebrovascular events, congestive heart failure and atrial and ventricular arrhythmias during the hospital period. Mortality declined by one-third between the two periods. However, the mortality rate of patients with AMI who sustained a cerebrovascular event remained high (> or =40% for 30 days, 60% for 1 year).

CONCLUSIONS

The overall incidence of early cerebrovascular events complicating AMI remained similar (0.75%) in the prethrombolytic and thrombolytic eras. Mortality rates of patients with an AMI but no cerebrovascular events decreased substantially over the past decade but not in patients with AMI with a cerebrovascular event.

Ischemic stroke after acute myocardial infarction. A population-based study

BACKGROUND AND PURPOSE

Modern treatment may have influenced the risk of stroke after myocardial infarction (MI). The purpose of this study was to examine the incidence of ischemic stroke during the first month after an acute MI in an unselected population, to identify predictors of MI-related stroke, and to investigate the secular trend in MI-related stroke incidence.

METHODS

In this case-control study, from a population of approximately 310000 25- to 74-year-old inhabitants, case subjects with a stroke within 1 month after an MI were prospectively recorded in the population-based Northern Sweden MONICA (Monitoring of Trends and Determinants in Cardiovascular Disease) study from 1985 to 1994. The same number of control subjects with an MI but without a stroke were matched for age, sex, and year when MI occurred.

RESULTS

One hundred twenty-four case subjects were recorded. Fifty-one percent (63/124) of the strokes occurred within 5 days after onset of MI. The odds ratios (ORs) of an MI-related stroke were for a history of hypertension 1.7 (95% confidence interval [CI], 1.0 to 3.2), previous stroke 2.4 (CI, 1.0 to 6.1), chronic atrial fibrillation 3.0 (CI, 1.1 to 9.2), onset of atrial fibrillation during the hospital stay 3.5 (CI, 1.4 to 10.1), ST-segment elevation 2.4 (CI, 1.4 to 4.6), and anterior infarction 1.5 (CI, 0.9 to 2.6). In a conditional multiple logistic regression model, previous stroke (OR, 2.8; CI, 1.1 to 7.6), chronic atrial fibrillation (OR, 3.8; CI, 1.3 to 11.0), new-onset atrial fibrillation (OR, 4.6; CI, 1.6 to 12.8), and ST-segment elevation (OR, 3.4; CI, 1.6 to 7.4) were independent predictors of stroke. MIs preceding stroke were larger and in 51% were located anteriorly. There was a decrease in the incidence and event rate of MI-related stroke during the study period (P < .01 and P < .05, respectively).

CONCLUSIONS

The risk of stroke is highest the first 5 days after MI. Only approximately half of the strokes occurring the first month after an MI are preceded by an anterior MI. The most important predictors of MI-related stroke are atrial fibrillation (chronic or new onset), ST elevation, and a history of a previous stroke. There is a long-term trend toward a lower incidence of MI-related stroke. These findings have important implications concerning both the pathophysiology and prevention of MI-related stroke.

Ventricular dysfunction and the risk of stroke after myocardial infarction

BACKGROUND

In patients who have had a myocardial infarction, the long-term risk of stroke and its relation to the extent of left ventricular dysfunction have not been determined. We studied whether a reduced left ventricular ejection fraction is associated with an increased risk of stroke after myocardial infarction and whether other factors such as older age and therapy with anticoagulants, thrombolytic agents, or captopril affect long-term rates of stroke.

METHODS

We performed an observational analysis of prospectively collected data on 2231 patients who had left ventricular dysfunction after acute myocardial infarction who were enrolled in the Survival and Ventricular Enlargement trial. The mean follow-up was 42 months. Risk factors for stroke were assessed by both univariate and multivariate Cox proportional-hazards analysis.

RESULTS

Among these patients, 103 (4.6 percent) had fatal or nonfatal strokes during the study (rate of stroke per year of follow-up, 1.5 percent). The estimated five-year rate of stroke in all the patients was 8.1 percent. As compared with patients without stroke, patients with stroke were older (mean [+/-SD] age, 63+/-9 years vs. 59+/-11 years; P<0.001) and had lower ejection fractions (29+/-7 percent vs. 31+/-7 percent, P=0.01). Independent risk factors for stroke included a lower ejection fraction (for every decrease of 5 percentage points in the ejection fraction there was an 18 percent increase in the risk of stroke), older age, and the absence of aspirin or anticoagulant therapy. Patients with ejection fractions of < or = 28 percent after myocardial infarction had a relative risk of stroke of 1.86, as compared with patients with ejection fractions of more than 35 percent (P=0.01). The use of thrombolytic agents and captopril had no significant effect on the risk of stroke.

CONCLUSIONS

During the five years after myocardial infarction, patients have a substantial risk of stroke. A decreased ejection fraction and older age are both independent predictors of an increased risk of stroke. Anticoagulant therapy appears to have a protective effect against stroke after myocardial infarction.

Methodologic sources of inconsistent prognoses for post-acute myocardial infarction

PURPOSE

To investigate basic methodologic problems that could explain inconsistent and contradictory results for predictor variables in studies of prognosis after myocardial infarction (MI).

MATERIALS AND METHODS

Studies on postinfarct prognosis published in English between 1979 and 1991 were identified with a MEDLINE literature search. The key words used for the computer search were: "prognosis" and "myocardial infarction" in the title and "mortality" or "survival" or "outcome" in the title or abstract. Reference lists in the reports captured by the search were examined for pertinent articles, and additional articles were sought in the index pages of two prominent journals. To be included in the analysis, a study had to fulfill the following eligibility criteria: a cohort study or randomized, controlled trial; sample size > or = 50 patients; a clear identification of the time when follow-up began, after the acute phase of MI and either before or at hospital discharge; follow-up for a minimum of 6 months or median/mean of 1 year; and multivariable analysis for intervals no longer than 2 years after the MI. Eight methodologic standards addressing sources of major problems were established and applied to each study.

RESULTS

Of 766 reports identified, 111 fulfilled the eligibility criteria. The median number of standards fulfilled was 3, the highest 6. The proportions of studies complying with each of the 8 methodologic standards were: (1) inception cohort, 60%; (2) total death as an unequivocal outcome, 54%; (3) verification of cause-specific deaths (in 62 studies analyzing cardiac death), 37%; (4) analysis of crucial variables describing baseline severity, 13%; (5) indication of quantitative scope of the spectrum of baseline severity, 20%; (6) reproducible classification of candidate predictor variables, 40%; (7) adequate identification of quantitative importance of and boundaries for statistically significant predictor variables, 39%; and (8) evaluation of impact of treatment on predictor variables, 13%.

CONCLUSIONS

The results show that studies on postinfarct prognosis have frequently disregarded basic methodologic principles. Suitable adherence to these principles in future research will allow improved interpretation of results and can reduce inconsistent findings, while improving the applicability of the identified predictors.

Frequency and prognosis of stroke/TIA among 4808 survivors of acute myocardial infarction. The SPRINT Study Group

BACKGROUND AND PURPOSE

Stroke complicating acute myocardial infarction is associated with substantial morbidity and mortality. The purpose of this study was to assess the incidence, predictors, and impact on mortality of stroke/transient ischemic attacks occurring after hospital discharge in a large unselected population of acute myocardial infarction survivors.

METHODS

During a secondary prevention study with nifedipine (SPRINT), demographic, anamnestic, and clinical data were collected for 5839 consecutive acute myocardial infarction patients admitted to 13 coronary care units in Israel. Hospital survivors (n = 4808) were followed for a year after their discharge. Mortality was assessed for a mean follow-up of 5.5 years (range, 4.5 to 7 years).

RESULTS

One percent (48/4808) of hospital survivors from acute myocardial infarction experienced a stroke/transient ischemic attack in the year after acute myocardial infarction. Thirty-one percent (15 of 48) of events occurred in the first month after hospital discharge. Incidence was higher among older patients (> 70 years; 1.9%), those with anterior site of myocardial infarction (1.35%), a previous history of myocardial infarction (1.8%), hypertension (1.4%), stroke in the past (4.1%), and chronic atrial fibrillation (9%). Multivariate analysis identified the following as independent predictors of stroke/transient ischemic attacks occurring in the year after hospital discharge: chronic atrial fibrillation, older age, history of previous myocardial infarction, anterior myocardial infarction site, serum glutamic oxaloacetic transaminase levels more than four times above upper normal limits, and stroke in the past. The age-adjusted 1-year and long-term mortality rates (4.5 to 7 years; mean, 5.5 years) were significantly higher in patients with (31% and 62%) than in those without stroke/transient ischemic attacks (9% and 31%, respectively; P < .01).

CONCLUSIONS

Stroke/transient ischemic attack is a relatively rare (1%) complication in the year after hospital discharge from acute myocardial infarction, though more frequent in the first month. Chronic atrial fibrillation, older age, anterior myocardial infarction site, serum glutamic oxaloacetic transaminase levels more than four times above upper normal limits, past myocardial infarction, and stroke identify high-risk patients. Patients suffering from subsequent stroke/transient ischemic attacks experienced higher mortality than counterparts who remained free from this complication.

Infection as a risk factor for infarction and atherosclerosis

A growing amount of clinical and experimental evidence suggests a link between infection and atherosclerotic diseases including both myocardial and cerebral infarction. A prime example is a greatly increased risk of stroke in septicaemic patients with and without endocarditis. Controlled clinical studies have recently shown, however, that certain other milder bacterial infections are also a risk factor for infarction. A preceding febrile respiratory infection was a major risk factor for stroke in young and middle aged patients. In patients with acute myocardial infarction Chlamydia pneumoniae and dental infections seem to be risk factors according to one controlled clinical study. Several possible mechanisms could explain the observed association of infection and infarction. For instance, infection causes a hypercoagulable state which increases the risk of thrombosis. In addition, infection has profound and harmful effects on prostaglandin and lipid metabolism. Infection may also have some role in the atherosclerotic process itself by inducing damage and inflammation in vascular endothelium in the presence of hypercholesterolemia. So far, however, little clinical evidence is available to suggest that by controlling infection the risk of infarction or development of atherosclerotic lesions might be reduced except in patients with endocarditis, where the risk of thromboembolic complications rapidly diminished when the infection is controlled with antimicrobial therapy.