Article Text
Abstract
A shortcut review was carried out to establish whether ST elevation in aVR accurately identifies acute myocardial infarction caused by left main coronary artery stenosis. 141 unique papers were found in Medline, EMBASE, Cochrane Database of Systematic Reviews, ACP Journal Club and the Database of Abstracts of Reviews of Effects using the reported searches. Of these, 12 presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these best papers are tabulated. It is concluded that ST elevation in aVR can identify high-risk patients for early intensive investigation, particularly when found alongside widespread ST depression. It has insufficient utility to identify patients who require immediate revascularisation.
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Clinical scenario
A 60-year-old man presents to the emergency department with typical cardiac chest pain but is now pain free. His ECG is not diagnostic of ST elevation myocardial infarction (STEMI) but shows 1.5 mm ST segment elevation in lead aVR. Having visited a number of educational websites, you recognise that this finding may signify left main coronary artery (LMCA) occlusion. Concerned about the potential risks associated with both failure to recognise such an important and potentially life-threatening diagnosis and with those associated with over-diagnosis, over-investigation and over-treatment, you wonder whether the presence of ST elevation in aVR is a specific marker of that diagnosis.
Three-part question
In [patients with suspected acute coronary syndromes and an ECG that is non-diagnostic for STEMI] does [ST elevation in lead aVR] accurately identify [acute myocardial infarction caused by LMCA stenosis]?
Search strategy
The following databases were searched using the Ovid interface: EBM Reviews—Cochrane Database of Systematic Reviews 2005–November 2014, EBM Reviews—ACP Journal Club 1991–December 2014, EBM Reviews—Database of Abstracts of Reviews of Effects 4th Quarter 2014, Ovid MEDLINE(R) 1946–January Week 2 2014 and Embase 1974–2014 Week 02.
The following search strategy was employed:
(exp ST segment elevation/OR exp ST segment elevation myocardial infarction/OR exp Angina, Unstable/OR exp Percutaneous Coronary Intervention/OR exp Acute Coronary Syndrome/OR exp heart infarction/OR exp Coronary Artery Disease/OR exp Myocardial Infarction/) AND (aVR.mp.) AND (anterior interventricular artery.mp. OR left main coronary artery.mp. OR left coronary artery.mp. OR LCA.mp. OR LMCA.mp. OR left main stem.mp. OR left main stem coronary artery.mp. OR LMS.mp. OR left main trunk.mp.) limit to human and English language.
Outcome
In total, 185 papers were identified, of which 44 were duplicates leaving 141 titles and abstracts for review. We excluded conference abstracts where insufficient data were available to enable the evidence to be appraised. This yielded a total of 12 papers for appraisal. One of these was a systematic review that summarised the evidence from five of the papers (see table 2).
Comments
All the papers appraised note an association between this pattern and severe stenosis of the LMCA or 3-vessel disease. However, the evidence identified from nine cohort studies consistently shows that lone ST elevation in lead aVR has little diagnostic value for identifying patients with stenosis of the LMCA. Both sensitivity and specificity are suboptimal to guide clinical decision making. The evidence suggests that diagnostic performance may improve when there is accompanying diffuse ST depression. Kosuge et al 8 found that such changes have a specificity of 93% for LMCA stenosis or 3-vessel disease, although the positive predictive value in that sample was only 58%, which limits the value of the finding for ‘ruling in’ LMCA stenosis. As such, taken alone this finding could not be used to guide the need for primary percutaneous coronary intervention, for example. However, as patients with LMCA stenosis are at particularly high risk, ST elevation in aVR may help to identify patients for early aggressive investigation.
Clinical bottom line
ST elevation in aVR can identify high-risk patients with LMCA stenosis for early intensive investigation, particularly when found alongside widespread ST depression. It has insufficient utility to identify patients who require immediate revascularisation.
Footnotes
Provenance and peer review Not commissioned; internally peer reviewed.