Limitations of the study evaluating fibrinolytic therapy and in-hospital PCI for ST-elevation myocardial infarction

Faizel Osman

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

Sohail Qaisar

Department of Cardiology
Heartlands Hospital
Birmingham B9 5SS
UK

Nadia El Gaylani

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 2–3 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

  1. McClelland AJJ, Owens CG, Walsh SJ, McCarty D, Mathew T, Stevenson M, Gracey H, Khan MM, Adgey AAJ. Percutaneous coronary intervention and 1 year survival in patients treated with fibrinolytic therapy for acute ST-elevation myocardial infarction. Eur Heart J 2005;26:544–548.[Abstract/Free Full Text]
  2. Gersh BJ, Stone GW, White HD, Holmes DR. Pharmacological facilitation of primary percutaneous coronary intervention for acute myocardial infarction. Is the slope of the curve the shape of the future? JAMA 2005;293:979–986.[Abstract/Free Full Text]
  3. Danchin N. Percutaneous coronary intervention following intravenous fibrinolytic therapy: should it be a must? Eur Heart J 2005;26:529–531.[Free Full Text]




This Article
Full Text (PDF)
All Versions of this Article:
26/16/1684    most recent
ehi361v1
Alert me when this article is cited
Alert me if a correction is posted
Services
Email this article to a friend
Similar articles in this journal
Similar articles in ISI Web of Science
Similar articles in PubMed
Alert me to new issues of the journal
Add to My Personal Archive
Download to citation manager
Request Permissions
Google Scholar
Articles by Osman, F.
Articles by El Gaylani, N.
PubMed
PubMed Citation
Articles by Osman, F.
Articles by El Gaylani, N.