Author + information
- C. Richard Conti, MD⁎ ()
- ↵⁎University of Florida Health Science Center, Room M-438, 1600 Southwest Archer Road, PO Box 100277, Gainesville, Florida 32610-0277
I would like to congratulate the authors for their paper the mini-focus issue on the ST-segment elevation myocardial infarction (STEMI) (1), for calling attention to the fact that door-to-balloon time might not be the best metric to assess successful treatment of STEMI (2). In their State-of-the-Art paper, the authors clearly point out that measuring door-to-balloon time ignores, for the most part, the pre-hospital phase of myocardial infarction. In the piece that I wrote for Clinical Cardiology, I made the point that door-to-balloon time is certainly a-metric (i.e., easy to measure and can be documented accurately). Unfortunately, in the human it is nearly impossible to measure the precise onset of occlusion of a coronary artery. Many patients can present with stuttering chest pain for many hours before arriving in the emergency department, at which time that is the first indication of ST-segment elevation, and that is when door-to-balloon time is calculated.
There is no question that door-to-balloon time has been studied carefully and correlates well with successful outcomes. However, it does not take into account several factors that might influence the outcome positively or negatively. It seems to me that attention to details of the individual parameters noted before, during, and after percutaneous coronary intervention in STEMI patients might make a difference in outcome and should be considered when metrics of successful management of acute STEMI are being considered by oversight or regulatory bodies.
There are several clinical conditions that might influence outcome. For example:
Patients who have had a previous infarction might have a worse outcome than patients who present with a first infarction.
If chronic angina was present before STEMI, outcome might be better, because collaterals might be present.
If the patient was diabetic and not well-controlled, outcome might be poorer than a patient who is not diabetic.
If the patient was markedly hypertensive, outcome might be poorer than if the patient was normotensive or well-controlled with drugs.
If the patient had chronic obstructive pulmonary disease, outcome might be poorer than if the patient had normal lung function.
All these parameters, as far as I can tell, have not really been addressed in the classic articles on door-to-balloon time in patients presenting with STEMI.
Thus, I share the belief (and evidence) of the authors that mortality is strongly correlated with total ischemic time. However, I also would add other factors that might contribute to mortality that are not really counted when the only metric measured is door-to-balloon time.
- American College of Cardiology Foundation