NIH Public Access Author Manuscript J Cardiovasc Dis. Author manuscript; available in PMC 2014 January 06.

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Published in final edited form as: J Cardiovasc Dis. 2014 January ; 2(1): 1–3.

The Impact of Myocardial Infarction vs. Pneumonia on Outcome in Acute Ischemic Stroke

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Tiffany L. Mathias, BS, Karen C. Albright, DO, MPH, Amelia K Boehme, MSPH, Dominique Monlezun, BA, Alexander J. George, BS, Erica Jones, BS, T. Mark Beasley, PhD, and Sheryl Martin-Schild, MD, PhD* Stroke Program, Department of Neurology, Tulane University Hospital, New Orleans, LA 70112 (TLM, DM, AJG, EJ, SMS); Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35249 (KCA, AKB); Health Services and Outcomes Research Center for Outcome and Effectiveness Research and Education (COERE) (KCA); Center of Excellence in Comparative Effectiveness Research for Eliminating Disparities (CERED) Minority Health & Health Disparities Research Center (MHRC) (KCA); Department of Biostatistics, School of Public Health, University of Alabama at Birmingham, Birmingham, AL 35249 (TMB)

Abstract The aim of this study was to examine the association between MI and PNA in the setting of acute ischemic stroke and patient outcome. Eligible patients were identified from a prospectively collected stroke registry and included if transthoracic echocardiography (TTE) was performed during their inpatient stay. 426 patients met inclusion criteria (mean age 64, 73% Black, 48% female). Twenty-one patients (4.9%) experienced an MI. Patients who later suffered a MI initially presented with more severe strokes (median NIHSS 7 vs. 5, p=0.014). More patients in the MI group experienced pneumonia (26% vs. 9%, p=0.004). After adjusting for age, baseline glucose and NIHSS, the odds of in-hospital mortality for patients with MI was 3 times that of those without MI (OR 3.2 95% CI 1.1–9.7, p=0.036). When adjustment was made for pneumonia, age, baseline glucose and NIHSS, MI was no longer significantly related to in-hospital mortality (OR 2.5 95% CI 0.8–8.2, p=0.131). In our sample, while MI was significantly associated with inhospital mortality, this association was attenuated after adjusting for presence of pneumonia. Our findings raise the question as to whether the prevention of pneumonia could improve in-hospital mortality among patients who experience MI in the setting of ischemic stroke.

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Keywords myocardial infarction; ischemic stroke; in-hospital mortality

I. Introduction A cute ischemic stroke (AIS) and myocardial infarction (MI) share similar atherosclerotic pathophysiologic mechanisms and risk factors, leading to an intricate and codependent relationship between the two.1–3 Brain tissue affected by AIS loses auto-regulatory mechanisms, forcing cerebral blood flow to become more dependent on cardiac function for appropriate perfusion. Further, AIS patients may experience elevated afterload and systolic dysfunction, resulting in higher in-hospital mortality, and high blood pressure being associated with poor clinical outcomes.4, 5 Despite this, previous research has shown that

*

Correspondence to Dr. Sheryl Martin-Schild ([email protected])..

Mathias et al.

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low left ventricular ejection fraction (LVEF) is not an independent, significant predictor of short term functional outcome in ischemic stroke patients after adjusting for stroke severity and admission glucose.6 Cardiotoxic catecholamines induce a cyclic AMP-mediated increase in cellular Ca2+ overload as well as a vasospasm of epicardial coronary arteries, further exacerbating cardiac injury during AIS.7 This same overactivity of the sympathetic nervous system can cause immunodeficiency, rendering patients more vulnerable to infection, including pneumonia (PNA).8 PNA has been shown to influence outcomes in AIS patients with an increased odds of poor functional outcome even after adjustment.9 The aim of this study was to examine the association between MI in the setting of acute ischemic stroke, patient outcomes and other clinical factors.

II. Methods

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We conducted a single-site cross-sectional analysis of patients with acute ischemic stroke admitted to our stroke center between July 1, 2008 and December 31, 2010. Eligible patients were identified retrospectively from a prospectively collected stroke registry and included if transthoracic echocardiography (TTE) was performed during their inpatient stay. MI was defined as troponin >1.0 ng/mL in the setting of clinical symptoms or electrocardiogram changes.10 Baseline demographic information, imaging studies, laboratory values, and early outcomes were collected.11 Stroke severity was measured using the National Institutes of Health Stroke Scale (NIHSS). Stroke subtype was defined according to Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification.12 As previously described, pneumonia was defined as a new infiltrate on chest radiography with appropriate clinical signs and symptoms.13 Good functional outcome was defined as a modified Rankin Scale score (mRS) of 0–2. MI and non-MI groups were compared using Pearson Chi-square and Wilcoxon Rank Sum. Logistic regression was used to assess the odds of in-hospital mortality.

III. Results

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Four hundred and twenty-six patients met inclusion criteria (mean age 64, 73% Black, 48% female). Twenty-one patients (4.9%) had an MI during hospitalization for AIS. Table 1 provides the baseline comparison between the MI and non-MI groups. There was no significant difference in age, race, or gender between the MI and non-MI groups. A significantly higher proportion of patients in the MI group had a past medical history that included coronary artery disease (p

The Impact of Myocardial Infarction vs. Pneumonia on Outcome in Acute Ischemic Stroke.

The aim of this study was to examine the association between MI and PNA in the setting of acute ischemic stroke and patient outcome. Eligible patients...
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