Author + information
- Cindy L. Grines, MD, FACC* ( and )
- William O'Neill, MD, FACC
- ↵*William Beaumont Hospital, 3601 13 Mile Road, Royal Oak, MI 48073
We thank Drs. Sutton and Belder for their interest in our paper (1) and again wish to compliment Sutton et al. (2) on undertaking the largest rescue angioplasty trial conducted to date. It appears that we were using an earlier version of the study when commenting on the required sample size of 3,000 patients, and for this we apologize. But all parties agree that one could not expect a significant reduction in mortality given the small sample size and control group mortality of only 11%.
Although we can debate whether nonanterior myocardial infarction (MI) is the same as inferior MI, it is clear that patients who present with inferior ST-segment elevation have a smaller infarct size (3) and better prognosis than patients with anterior MI (4). Moreover, given the low baseline risk of inferior MI patients, it has been difficult to prove a mortality advantage with reperfusion therapy compared to placebo (4).
So what have we learned from the MERLIN trial? It is clear that rescue angioplasty has room for improvement. Consistently, rates of Thrombolysis In Myocardial Infarction (TIMI) flow grade 3 after rescue percutaneous coronary intervention (PCI) are lower than those reported after primary PCI. We had hoped that extraction of thrombosis or use of distal protection devices would improve perfusion and clinical outcomes. Yet large, randomized trials using distal protection (EMERALD trial) or thrombectomy (AIMI trial) showed no improvement in TIMI flow grades, myocardial blush scores, infarct size, or major adverse cardiac events compared to PCI alone (5). The lack of benefit may have been due to embolization with saline agitation, advancing the device past the thrombotic lesion or diverting emboli into proximal side branches. Therefore, it is possible that use of lower-profile thrombectomy catheters, filters, or proximal protection devices may be of benefit.
We agree with the MERLIN investigators that the focus should not be on rescue PCI, but on how to deliver primary angioplasty to a larger population. Performance of primary PCI (by an experienced PCI operator) in a diagnostic-only catheterization laboratory would increase availability enormously. We should work toward a goal of performing prehospital electrocardiography and transferring patients with ST-segment elevation myocardial infarction from home, directly to a primary PCI center.
- American College of Cardiology Foundation
- Grines C.L.,
- O'Neill W.W.
- Sutton G.C.,
- Campbell P.G.,
- Graham R.,
- et al.
- Gibbons R.J.,
- Christian T.F.,
- Hopfenspirger M.,
- et al.
- Fibrinolytic Therapy Trialists' (FTT) Collaborative Group
- ↵Ali A, for the AIMI Investigators. AngioJet rheolytic thrombectomy in patients undergoing primary angioplasty for acute myocardial infarction: the AIMI study. Presented at the Transcatheter Cardiovascular Therapeutics Symposium. Washington, DC, September 2004.