PCI versus Thrombolytics for Acute MI
Search Strategy: Reading through the EM summary of the 2004 American College of Cardiology Guidelines for the Management of STEMI (Annals EM 2005; 45: 363-376), you note reference number 64 which summarizes Keeley’s 2003 meta-analysis to justify a statement on the superiority of PCI. Reviewing Keeley’s report, you find a reference to GUSTO IIb (1997) as one of the largest primary (randomized, controlled) trials which you elect to review as representative of those summarized in the meta-analysis. Entering “Keeley E* 2003” as a PUBMED search term and then selecting Related Articles, you obtain 397 hits including: a Cochrane Review (updated in 2003) and the PCAT Collaborators which looked at long-term outcomes when the two reperfusion strategies were compared. Looking for more recent evidence, you next search the Web of Science for articles which have referenced Keeley’s article, obtaining 321 such citations of which one is Boersma’s meta-analysis evaluating the effect of time to reperfusion on PCI versus thrombolytics.
The EM faculty of your hospital is divided on whether percutaneous cardiac intervention (PCI) is superior or merely equivalent to thrombolytic (tPA) therapy of acute ST-segment elevation myocardial infarction (STEMI). As the Evidence Based Medicine (EBM) guru of your group, fresh out of a residency which trained you to ask an answerable question before finding and appraising the best available evidence, you are determined to help define standard of care for your group and your hospital.
Your interventional Cardiologists have recently decided that the best policy dictates that optimal reperfusion strategies should be decided by the EM physician who can adequately assess the initial ECG, patient thrombolytic contraindications, and complicating co-morbidities. However, only one interventional group currently exists at your hospital and they have a low threshold for erroneous activation of the catheterization lab team during off-hours when no in-house staffing exists. Therefore, the pressure is on the EM staff to quickly and accurately identify STEMI patients who would most benefit from PCI rather than tPA. Some among your staff believe every patient with STEMI would benefit more from PCI than tPA. Uncertain, you turn to the literature.
Population: ED patients presenting with STEMI
Intervention: PCI reperfusion
Comparison: Thrombolytic reperfusion
Outcome: Short-term cardiac mortality, long-term mortality, bleeding complications, cardiovascular functional status and co-morbidity
First years: A Clinical Trial Comparing Primary Coronary Angioplasty with Tissue Plasminogen Activator for Acute Myocardial Infarction (GUSTO IIb), NEJM 1997; 336: 1621-1628.
Second years: Primary Angioplasty Versus Intravenous Thrombolytic Therapy for Acute Myocardial Infarction: A Quantitative Review of 23Randomised Trials. Lancet 2003; 361: 13-20.
Third years: Primary Coronary Angioplasty Compared with Intravenous Thrombolytic Therapy for Acute Myocardial Infarction: Six-month Follow-up and Analysis of Individual Patient Data from Randomized Trials. Am Heart J 2003; 145: 47-57.
Fourth years: Does Time Matter? A Pooled Analysis of Randomized Clinical Trials Comparing Primary Percutaneous Coronary Intervention and In-hospital Fibrinolysis in Acute Myocardial Infarction Patients. Eur Heart J 2006; 27: 779-788.
Article 1: Clinical Trial Comparing Primary Coronary Angioplasty with Tissue-Plasminogen Activator for Acute Myocardial Infarction (GUSTO-IIb), NEJM 1997; 336: 1621-1628
Article 2: Primary angioplasty versus intravenous thrombolytic therapy for AMI. Lancet 2003; 361: 13-20
Article 3: Primary CoronaryAngioplasty Compared with Intravenous Thrombolytic Therapy for Acute Myocardial Infarction: Six-month Follow-up and Analysis of Individual Patient Data from Randomized Trials, Am Heart J 2003; 145: 47-57
Article 4: Does Time Matter? A Pooled Analysis of Randomized Clinical Trials Comparing Primary Percutaneous Coronary Intervention and In-hospital Fibrinolysis in Acute Myocardial Infarction Patients, Eur Heart J 2006; 27: 779-788
Multiple trials have now demonstrated the superiority of primary PCI over t-PA thrombolytics for reperfusion therapy during acute myocardial infarction. Delays to reperfusion only widen the gap between PCI and thrombolytics and most studies have not yet evaluated the impact of newer anti-platelet agents and stents on this difference. The benefit of PCI over thrombolytics is likely under-estimated by all of the current meta-analyses. The current data alone, however, support the statement that PCI ought to be considered the standard of care wherever it can be cost-effectively applied in centers with cardiac catheterization volumes similar to those previously studied (> 200 caths/year). As each meta-analysis succinctly concludes, one size does not fit all and certain situations may dictate the need for thrombolytics (rural communities without the resources to offer round-the-clock thrombolytics, tertiary care centers where the cath lab is already occupied, etc.). Cath lab inconvenience during off-hours, though, should not be an indication for thrombolytics over PCI as the two therapies are not equal as measured by death, recurrent MI, or non-fatal stroke.