Management Strategies For Unstable Angina / NSTEMI
A meta-analysis conducted by Michelle O'Donoghue MD and colleagues and published in the Journal of the American Medical Association (JAMA) reccomends that men and women with high-risk unstable angina/non-ST-segment elevation myocardial infarction (UA/NSTEMI) should have an invasive management strategy as part of their treatment. It goes on to posit however that low-risk women should be treated with a greater degree of conservatism. The analysis is based on randomized trials eight in total. The published report compares eight trials of invasive versus conservative strategies for the treatment of both genders with UA/NSTEMI in the July Second issue of JAMA. The researchers trawled the databases of Medline and Cochrane in order to identify randomized controlled trials which were conducted between 1970 and April of 2008. The trials selected analysed a management style which could be characterised as invasive defined as referring the patient for coronary angiography preceded by revascularization if considered appropriate. This was contrasted with a management style which could be characterised as conservative and defined as pharmacologic management with only subsequent coronary angiography chosen for selected cases as the primary strategy. 10 412 patients were randomized to either an invasive strategy or a conservative one. 1571 women and 3641 men for invasive and 1581 women and 3619 men for conservative. From this data the research team concludes that there was a comparable benefit with an invasive management strategy in lowering the odds ratio of death MI or the need for further hospitalization for acute coronary syndrome in biomarker-positive males low-risk biomarker-negative men and bio-marker positive women. There was an insignificant rise in odds ratio for death or MI discovered in the data for low-risk females managed with a strategy characterised as invasive. Therefore Dr. O'Donoghue and her team reccomend a conservative management strategy for low-risk women suffering from UA/NSTEMI. The guidelines jointly published in 2007 by the American Heart Association (AHA) and the American College of Cardiology (ACC) advise that the management of patients with UA/NSTEMI should involve an initial invasive strategy for patients with refractory angina and/or hemodynamic or electrical instability who are stabilized in the initial stages of treatment but whose risk of further elevations for clinical events is high. The characteristics which should be considered high-risk are to include reccurent angina or ischemia at rest with low-level activities even through intensive medical therapy elevated cardiac biomarkers new or assumed new ST-segment depression symptoms or signs of heart failure or worsening mitral regurgitation high-risk findings from non-invasive testing hemodynamic instability sustained ventricular tachycardia percutaneuous coronary intervention within six months prior coronary artery bypass graft surgery elevated thrombolysis in Myocardial infarction risk score or reduced left ventricular function (reduced by more than 40%). A management strategy characterised as conservative then is preferred for those presenting with a low TIMI risk score or may be considered preferred in the absence of high-risk features by either patient or doctor. Benefits have been found consistently in clinical trials of UA/NSTEMI males for an invasive strategy however corresponding results for women have not been shown. Guidelines proffered by the ACC and AHA posit that women suffering from UA/NSTEMI who can be characterised as high-risk appear to draw benefit from an invasive strategy in conjunction with glycoprotein IIb/IIIA antagonist use. Low-risk women however do not appear to benefit from such strategies. The ACC/AHA support the view that the body of evidence shows a possible excess risk in using invasive strategy in those women who are considered low-risk. The meta-analysis carried out by Dr. O'Donoghue would appear to support such a conclusion.