Department of Cardiology
Heartlands Hospital
Bordesley Green East
Birmingham B9 5SS
UK
Tel: +44 121 424 3737
Fax: +44 121 424 1074
E-mail address: f.osman{at}bham.ac.uk
Department of Cardiology
Heartlands Hospital
Birmingham B9 5SS
UK
Department of Cardiology
Heartlands Hospital
Birmingham B9 5SS
UK
We read with interest the article by McClelland et al.1 entitled Percutaneous coronary intervention and 1-year survival in patients treated with fibrinolytic therapy for acute ST-elevation myocardial infarction. We would like to congratulate the authors on their study, but would like to highlight a few limitations that may have influenced the study findings.
The 154 patients treated by in-hospital percutaneous coronary intervention (PCI) in the study received fibrinolytic therapy more quickly compared with those who had no in-hospital PCI; the median pain-to-needle time was significantly shorter in those who later underwent PCI than those who did not. This would have clearly influenced the outcome, as those in the PCI group were likely to have salvaged more myocardium. The median time difference between the two groups was 1.4 h and when we consider that minutes means muscle, 1.4 h implies a lot of muscle. A recent systematic review article by Gersh et al.2 suggests that patients presenting within the first 23 h of symptom onset benefit most in terms of myocardial salvage by undergoing prompt reperfusion therapy. This being the case, those in the PCI group of the study by McClelland et al.1 would have benefited more, not necessarily because of in-hospital PCI but rather because of more prompt reperfusion with fibrinolytic therapy with a resultant bias favouring the PCI group.
A second factor that may have favoured the PCI group was also eluded in the accompanying editorial by Danchin.3 The majority of patients in the PCI group went to the cardiac catheter lab >24 h after admission (59%). This means that patients in the PCI group had survived at least up till the point of being taken to the cath lab. Those who died very early on in their admission may not have been taken to the cath lab because of this delay and would have been counted within the non-PCI group, resulting in bias favouring the PCI group.
McClelland et al.1 do not provide any data on the usage of platelet glycoprotein IIb/IIIa inhibitors in their study. The combination of fibrinolytics with these agents has raised concerns about bleeding risks of subsequent PCI, but there is a paucity of data.2 However, clarification concerning the use of such agents would provide the reader with useful information.
We once again congratulate the authors on their study of this important topic, but highlight some limitations that may have affected its findings.
References
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