Letters Section Editor: Stephen J. Lurie,
MD, PhD, Senior Editor.
To the Editor: Dr Neumann and colleagues1 found that in patients with unstable coronary syndromes,
those who had deferred catheter intervention for prolonged antithrombotic
pretreatment ("cooling off") had somewhat worse outcomes than those who had
immediate intervention accompanied by intense antiplatelet treatment.
I would appreciate it if the authors would provide additional details
regarding the definitions and timing of nonfatal reinfarction. In particular,
it is unclear how they decided whether to classify an infarction as an index
event or as an end point. This seems especially problematic, as 67% of all
patients had elevated levels of cardiac troponin T at presentation. It would
be of interest to know how many patients in each group had elevated levels
of creatine kinase and its MB isoenzyme at presentation. This is particularly
important, as an end-point infarction was defined as "new Q waves in 2 or
more contiguous electrocardiographic leads" in 11 of 33 patients. In the remaining
22 patients it was defined as levels of creatine kinase and MB isoenzyme that
were 5 or more times the upper limit of normal. Were the nonfatal infarctions
identified solely by the treating, unblinded physician or was there an independent,
blinded end point committee?
Goodman S. "Cooling-Off" vs Immediate Revascularization for Patients With Acute Coronary Syndromes. JAMA. 2004;291(6):691-692. doi:10.1001/jama.291.6.691-a