Author + information
- Andrew G.C. Sutton, MA, MB, MRCP* ( and )
- Mark A. de Belder, MA, MD, FRCP
- ↵*The James Cook University Hospital, Cardiothoracic Division, Marton Road, Middlesbrough, Cleveland TS4 3BW, United Kingdom
Some of the issues raised by Drs. Grines and O'Neill in their editorial in JACC(1) accompanying the Middlesbrough Early Revascularization to Limit Infarction (MERLIN) trial report (2) should be addressed.
Before the trial initiation, we estimated 18% mortality in the conservative group and 6% in the rescue group, as described in the statistical methods section. This may have been optimistic, but was based upon a careful literature search. Power calculations cannot be made on the basis of data that subsequently become available. In the discussion, we describe a 2% to 12% 30-day or hospital mortality among patients undergoing rescue angioplasty, but it is clear from the reference section that this includes data from studies published after initiation of the MERLIN trial.
It is extraordinary for the authors to suggest that we made the comment that 3,000 patients would be needed to show mortality benefit and that, knowing this, we went on to perform a trial on 300 patients. First, this comment does not actually appear in our study, having been removed (not at our request) during the review and editing process. Second, the figure of 3,000 is an estimation of the number required in each of the two arms in order to demonstrate significant reduction in coronary mortality at the levels we observed(11% conservative vs. 8.5% rescue). Their comments imply that the authors have not understood our power calculation and also that they have either reviewed our original study and been subsequently unaware of changes made by the editorial team, or been given the wrong draft to comment on in the editorial process.
We have not stated that the primary end point in the MERLIN trial is negative, but instead that we failed to demonstrate mortality benefit. Presentation of the results in open forum suggests that those in favor of rescue angioplasty have seen a slight benefit in mortality, as well as the perceived advantages of the combined end point, and interpret this as a reason to continue a rescue program. Conversely, skeptics interpret our results as confirming their belief that rescue angioplasty is performed too late to be beneficial.
We agree that the majority (56%) of our patients had nonanterior infarction, but this is not the same as inferior infarction and does not imply anything about infarct size. The investigators state that randomized trials and American Heart Association/American College of Cardiology guidelines suggest that clinical benefit from rescue angioplasty is confined to anterior myocardial infarction (MI). However, this is based almost entirely on data from the RESCUE trial (3), with its limitations as described. No randomized trial has demonstrated lack of benefit from rescue angioplasty in patients with nonanterior MI.
Despite the above comments, we suspect there is no major conflict. A successful rescue angioplasty frequently benefits the patient: the vessel opens, flow is restored, the ST segments come down, and there are no complications. However, it is an omission to make no comment on the potential for harm. The challenge is to identify those patients with most to gain and the lowest risk of harm.
We have not abandoned rescue angioplasty, and certainly not abandoned the open-artery hypothesis. We believe that primary angioplasty is the best treatment for ST-segment elevation myocardial infarction. However, while patients continue to receive fibrinolytics for ST-segment elevation myocardial infarction, the question of rescue remains. Our approach is a selective one, in line with the editorial view. Our current focus is on how to deliver primary angioplasty to a large population in the northeast of England with equitable access to care for all patients. If this can be achieved, the unanswered dilemmas of rescue angioplasty will become relatively less important.
- American College of Cardiology Foundation
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- O'Neill W.W.
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- Ellis S.G.,
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