Downloaded from http://pmj.bmj.com/ on March 6, 2015 - Published by group.bmj.com
Original article
Acute ischaemic stroke or transient ischaemic attack and the need for inpatient echocardiography Bijoy K Menon,1,2,3,4 Jonathan I Coulter,1 Simerpreet Bal,1 Catherine Godzwon,1 Sarah Weeks,5 Stuart Hutchison,5 Michael D Hill,1,2,3,4,6 Shelagh B Coutts1,2,4 1
Departments of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada 2 Departments of Radiology, University of Calgary, Calgary, Alberta, Canada 3 Community Health Sciences, University of Calgary, Calgary, Alberta, Canada 4 Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada 5 Department of Cardiac Sciences, University of Calgary, Calgary, Alberta, Canada 6 Departments of Medicine, University of Calgary, Calgary, Alberta, Canada Correspondence to Dr Bijoy K Menon, Departments of Clinical Neurosciences, University of Calgary, 1079 A, 29th Street NW, Calgary, Alberta, Canada T3H4J2; Bijoy.Menon@ Albertahealthservices.ca Received 25 June 2013 Revised 24 April 2014 Accepted 24 May 2014 Published Online First 11 June 2014
ABSTRACT Objectives To determine the diagnostic yield of echocardiography and its utility in changing medical management; and to derive a risk score to guide its use in patients with in-hospital stroke or transient ischaemic attack (TIA). Methods We carried out a retrospective chart review from January 2009 to June 2010 of patients with acute ischaemic stroke or TIA who had undergone transthoracic echocardiography (TTE) or transoesophageal echocardiography (TOE). Clinical and imaging findings at baseline were noted and ‘potential clinically relevant findings’ identified on TTE and TOE. A multivariable logistic regression was used to identify predictors of potential clinically relevant findings on TTE or TOE and derive a risk score. Results Of 370 patients, 307 (83.0%) had TTE and 63 (17.0%) had additional TOE. Potential clinically relevant findings on echocardiography were noted in 28 (7.6%) patients. Change in medical management was noted in 19/307 (6.2%) patients on TTE and in 7/63 (11.1%) patients on TOE. Male sex (OR 3.05, 95% CI 1.19 to 7.84; p=0.021), abnormal admission ECG (OR 4.39, 95% CI 1.79 to 10.79; p=0.001), and embolic pattern imaging at baseline (OR 2.38, 95% CI 1.05 to 5.40; p=0.038) were independent predictors of findings on TTE or TOE. A risk score including these three variables had modest discrimination (c-statistic 0.69, 95% CI 0.59 to 0.80). Conclusions Echocardiography detected potential clinically relevant findings in a minority of patients (7.6%), but these findings changed medical management 90.5% of the time. A risk score using sex, ECG abnormality, and embolic pattern imaging at baseline could help predict which patients are more likely to have these echo findings. INTRODUCTION
To cite: Menon BK, Coulter JI, Bal S, et al. Postgrad Med J 2014;90:434–438. 434
Cardiac investigations are often performed after acute ischaemic stroke in an effort to determine the potential source of embolism. These include an ECG, chest radiographs, Holter monitor assessment, echocardiography, and cardiac CT/MRI. Echocardiography is non-invasive, easily available, and has become the primary method of imaging the heart after stroke.1 Numerous cross-sectional studies have evaluated the diagnostic yield of transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE) in detecting potential clinically relevant echo findings. These studies have reported diagnostic yields ranging from 4–10% for TTE and 11–41% for TOE.2–6 Clinicians often wait until these tests are done before discharging these patients, prolonging
hospital stay. There is evidence to suggest that inpatient hospital costs, including length of stay, account for nearly 70% of first year acute care costs, of which 19% goes for diagnostic testing.7 Identifying a group of patients with a high probability of having a potential clinically relevant echocardiography finding, and triaging these patients for in-hospital echocardiography before discharge, while discharging patients with a low probability of these findings and possibly doing echo as an outpatient investigation, can limit the length of hospital stay and reduce wait times for hospital based diagnostic services. We aimed to determine the diagnostic yield of in-hospital TTE and TOE in detecting potential clinically relevant echo findings and to identify how frequently medical management changed as a result. Combining clinical and imaging information available at baseline, we then derived a risk model that might help clinicians predict the likely usefulness of in-hospital echocardiography.
METHODS Study population This was a single centre retrospective chart review of patients admitted to the Foothills Medical Center, Calgary from January 2009 to June 2010 with a diagnosis of acute ischaemic stroke or transient ischaemic attack (TIA). The stroke programme at the Foothills Medical Center serves the Calgary metropolitan area and surrounding communities with an estimated population of 1.2 million people and sees over 1500 stroke admissions/year. Inpatients with acute ischaemic stroke or TIA who had undergone TTE and/or TOE as part of their diagnostic evaluation within the predefined study period were included in the study. These patients were identified from a comprehensive electronic echocardiography database at our hospital. After excluding 69 patients with a history of atrial fibrillation or new onset atrial fibrillation detected in the emergency room or before echocardiography, 370 patients were included in the study (figure 1). The Conjoint Health Research Board of the University of Calgary approved the study.
Clinical variables Clinical variables including age, sex, baseline stroke severity (National Institute of Health Stroke Scale (NIHSS)), history of previous cardiac disease including congestive cardiac failure, coronary artery disease (CAD), valvular heart disease, prosthetic heart valves, congenital heart disease, previous strokes/TIA, history of hypertension, dyslipidaemia, smoking status, and alcohol abuse were collected
Menon BK, et al. Postgrad Med J 2014;90:434–438. doi:10.1136/postgradmedj-2013-132220
Downloaded from http://pmj.bmj.com/ on March 6, 2015 - Published by group.bmj.com
Original article Figure 1 Flowchart showing patient population, diagnostic yield of transthoracic echocardiography (TTE)/ transoesophageal echocardiography (TOE) and change in medical management with potential clinically relevant findings. Afib, atrial fibrillation; ER, emergency room.
from the chart review. In addition, information on the presence or absence of atrial fibrillation, use of antithrombotics/anticoagulation at admission, and abnormal cardiac examination including the presence of cardiac murmurs, clinical suspicion of congestive cardiac failure or infective endocarditis was also collected. The admission ECG was analysed and considered abnormal if there was evidence of any old or new ischaemia (septum, anterior, inferior). Neurovascular imaging at baseline (noncontrast CT (NCCT) brain, CT-angio head and neck, and MRI brain) was analysed and stratified into the following categories: normal, large artery involvement thought to explain brain infarct (extracranial or intracranial carotid, vertebral and basilar, intracranial middle cerebral artery (MCA) with atherosclerotic stenosis ≥50%; in patients with stenosis
Original article
Acute ischaemic stroke or transient ischaemic attack and the need for inpatient echocardiography Bijoy K Menon,1,2,3,4 Jonathan I Coulter,1 Simerpreet Bal,1 Catherine Godzwon,1 Sarah Weeks,5 Stuart Hutchison,5 Michael D Hill,1,2,3,4,6 Shelagh B Coutts1,2,4 1
Departments of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada 2 Departments of Radiology, University of Calgary, Calgary, Alberta, Canada 3 Community Health Sciences, University of Calgary, Calgary, Alberta, Canada 4 Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada 5 Department of Cardiac Sciences, University of Calgary, Calgary, Alberta, Canada 6 Departments of Medicine, University of Calgary, Calgary, Alberta, Canada Correspondence to Dr Bijoy K Menon, Departments of Clinical Neurosciences, University of Calgary, 1079 A, 29th Street NW, Calgary, Alberta, Canada T3H4J2; Bijoy.Menon@ Albertahealthservices.ca Received 25 June 2013 Revised 24 April 2014 Accepted 24 May 2014 Published Online First 11 June 2014
ABSTRACT Objectives To determine the diagnostic yield of echocardiography and its utility in changing medical management; and to derive a risk score to guide its use in patients with in-hospital stroke or transient ischaemic attack (TIA). Methods We carried out a retrospective chart review from January 2009 to June 2010 of patients with acute ischaemic stroke or TIA who had undergone transthoracic echocardiography (TTE) or transoesophageal echocardiography (TOE). Clinical and imaging findings at baseline were noted and ‘potential clinically relevant findings’ identified on TTE and TOE. A multivariable logistic regression was used to identify predictors of potential clinically relevant findings on TTE or TOE and derive a risk score. Results Of 370 patients, 307 (83.0%) had TTE and 63 (17.0%) had additional TOE. Potential clinically relevant findings on echocardiography were noted in 28 (7.6%) patients. Change in medical management was noted in 19/307 (6.2%) patients on TTE and in 7/63 (11.1%) patients on TOE. Male sex (OR 3.05, 95% CI 1.19 to 7.84; p=0.021), abnormal admission ECG (OR 4.39, 95% CI 1.79 to 10.79; p=0.001), and embolic pattern imaging at baseline (OR 2.38, 95% CI 1.05 to 5.40; p=0.038) were independent predictors of findings on TTE or TOE. A risk score including these three variables had modest discrimination (c-statistic 0.69, 95% CI 0.59 to 0.80). Conclusions Echocardiography detected potential clinically relevant findings in a minority of patients (7.6%), but these findings changed medical management 90.5% of the time. A risk score using sex, ECG abnormality, and embolic pattern imaging at baseline could help predict which patients are more likely to have these echo findings. INTRODUCTION
To cite: Menon BK, Coulter JI, Bal S, et al. Postgrad Med J 2014;90:434–438. 434
Cardiac investigations are often performed after acute ischaemic stroke in an effort to determine the potential source of embolism. These include an ECG, chest radiographs, Holter monitor assessment, echocardiography, and cardiac CT/MRI. Echocardiography is non-invasive, easily available, and has become the primary method of imaging the heart after stroke.1 Numerous cross-sectional studies have evaluated the diagnostic yield of transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE) in detecting potential clinically relevant echo findings. These studies have reported diagnostic yields ranging from 4–10% for TTE and 11–41% for TOE.2–6 Clinicians often wait until these tests are done before discharging these patients, prolonging
hospital stay. There is evidence to suggest that inpatient hospital costs, including length of stay, account for nearly 70% of first year acute care costs, of which 19% goes for diagnostic testing.7 Identifying a group of patients with a high probability of having a potential clinically relevant echocardiography finding, and triaging these patients for in-hospital echocardiography before discharge, while discharging patients with a low probability of these findings and possibly doing echo as an outpatient investigation, can limit the length of hospital stay and reduce wait times for hospital based diagnostic services. We aimed to determine the diagnostic yield of in-hospital TTE and TOE in detecting potential clinically relevant echo findings and to identify how frequently medical management changed as a result. Combining clinical and imaging information available at baseline, we then derived a risk model that might help clinicians predict the likely usefulness of in-hospital echocardiography.
METHODS Study population This was a single centre retrospective chart review of patients admitted to the Foothills Medical Center, Calgary from January 2009 to June 2010 with a diagnosis of acute ischaemic stroke or transient ischaemic attack (TIA). The stroke programme at the Foothills Medical Center serves the Calgary metropolitan area and surrounding communities with an estimated population of 1.2 million people and sees over 1500 stroke admissions/year. Inpatients with acute ischaemic stroke or TIA who had undergone TTE and/or TOE as part of their diagnostic evaluation within the predefined study period were included in the study. These patients were identified from a comprehensive electronic echocardiography database at our hospital. After excluding 69 patients with a history of atrial fibrillation or new onset atrial fibrillation detected in the emergency room or before echocardiography, 370 patients were included in the study (figure 1). The Conjoint Health Research Board of the University of Calgary approved the study.
Clinical variables Clinical variables including age, sex, baseline stroke severity (National Institute of Health Stroke Scale (NIHSS)), history of previous cardiac disease including congestive cardiac failure, coronary artery disease (CAD), valvular heart disease, prosthetic heart valves, congenital heart disease, previous strokes/TIA, history of hypertension, dyslipidaemia, smoking status, and alcohol abuse were collected
Menon BK, et al. Postgrad Med J 2014;90:434–438. doi:10.1136/postgradmedj-2013-132220
Downloaded from http://pmj.bmj.com/ on March 6, 2015 - Published by group.bmj.com
Original article Figure 1 Flowchart showing patient population, diagnostic yield of transthoracic echocardiography (TTE)/ transoesophageal echocardiography (TOE) and change in medical management with potential clinically relevant findings. Afib, atrial fibrillation; ER, emergency room.
from the chart review. In addition, information on the presence or absence of atrial fibrillation, use of antithrombotics/anticoagulation at admission, and abnormal cardiac examination including the presence of cardiac murmurs, clinical suspicion of congestive cardiac failure or infective endocarditis was also collected. The admission ECG was analysed and considered abnormal if there was evidence of any old or new ischaemia (septum, anterior, inferior). Neurovascular imaging at baseline (noncontrast CT (NCCT) brain, CT-angio head and neck, and MRI brain) was analysed and stratified into the following categories: normal, large artery involvement thought to explain brain infarct (extracranial or intracranial carotid, vertebral and basilar, intracranial middle cerebral artery (MCA) with atherosclerotic stenosis ≥50%; in patients with stenosis
