CORRESPONDENCE: LETTER TO THE EDITOR
Reply
Nico H.J. Pijls, MD, PhD*,
Pepijn van Schaardenburg, MD,
Ganesh Manoharan, MD,
Erik Boersma, PhD,
Jan-Willem Bech, MD, PhD,
Marcel van’t Veer, MSc,
Frits Bär, MD, PhD,
Jan Hoorntje, MD, PhD,
Jacques Koolen, MD, PhD,
William Wijns, MD, PhD and
Bernard de Bruyne, MD, PhD
* Catharina Hospital, Cardiology, Michelangelolaan 2, P.O. Box 1350, 5602-ZA Eindhoven, Noord-Brabant 5602, the Netherlands (Email: carias{at}cze.nl).
We do not believe that the rate of coronary artery bypass grafting in the reference group of the DEFER (Deferral Versus Performance of PTCA in Patients Without Documented Ischemia) study was high compared with that seen in other studies.
Although in the DEFER study the majority of patients had single-vessel disease, the reference group only consisted of those patients with proven ischemia (1). This is in contrast to the COURAGE (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) trial and many other trials. In those trials (2), patients were classified according to angiographic criteria, and it is well known that a significant number of angiographic stenoses in those patients is not functionally important (i.e., not responsible for reversible ischemia) and that from the functional point of view, angiographic 2- or 3-vessel disease often becomes 1-vessel disease in terms of inducible ischemia (3,4).
In fact, one of the reasons why outcome after medical treatment was reasonable compared with that seen with percutaneous coronary intervention (PCI) in the COURAGE trial has been the fact that in the PCI group, intervention was often performed on relatively mild lesions, many of them most likely not functionally significant. Performing PCI of such lesions (fractional flow reserve [FFR] >0.75) creates a negative bias for PCI as demonstrated in the perform group of the DEFER study. In contrast, also in the COURAGE trial, PCI of ischemia-related stenosis (equivalent of FFR <0.75 in a study) was significantly better than medical treatment.
At the time when the DEFER study was performed (1997 and 1998), no consistent definition of myocardial infarction in enzymatic terms existed, and an increase to more than twice the normal upper limit was often used. Nowadays, we would have taken a 3-fold increase as standardized in the recent guidelines of the European Society of Cardiology (5). This would not have made any fundamental difference for the outcome of the study.
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1. Pijls NHJ, van Schaardenburgh P, Manoharan G, et al. Percutaneous coronary intervention of functionally nonsignificant stenosis: 5-year follow-up of the DEFER study J Am Coll Cardiol 2007;49:2105-2111.[Abstract/Free Full Text]2. Boden WE, O’Rourke RA, Teo KK, et al. COURAGE Trial Research Group Optimal medical therapy with or without PCI for stable coronary disease N Engl J Med 2007;12:1503-1516. 3. Botman KJ, Pijls NHJ, Bech GJW, et al. Percutaneous coronary intervention or bypass surgery in multivessel coronary disease?. A tailored approach based on coronary pressure measurement. Cathet Cardiovasc Interv 2004;63:184-191.[CrossRef][Web of Science][Medline] 4. Sant’Anna FM, Silva EE, Batista LA, et al. Influence of routine assessment of fractional flow reserve on decision making during coronary interventions Am J Cardiol 2007;99:504-508.[CrossRef][Web of Science][Medline] 5. Thygesen K, Alpert JS, White HD. Universal definition of myocardial infarction Eur Heart J 2007;28:2525-2538.[Free Full Text]
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