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Time Is of the Essence

Improving door-to-balloon time provides our best opportunity to improve MI survival at present.

For patients with an ST-segment elevation myocardial infarction (STEMI), rapid treatment with angioplasty can be lifesaving, but timing is essential. The literature indicates that faster door-to-balloon times (the time from arrival at the hospital to the deployment of the balloon or device) are associated with clinically meaningful differences in survival. For each 15-minute decrement in door-to-balloon time from 150 minutes to less than 90 minutes, there are about 6 fewer deaths per 1000 patients treated. As noted by my colleagues and me in a review article in the current New England Journal of Medicine, it is also likely that faster door-to-balloon times benefit quality of life in survivors because of greater myocardial salvage. Among all the key quality-of-care processes that we track, improving time to angioplasty is the best opportunity to improve MI survival, based on current performance and what we can reasonably achieve.

Guidelines and national performance measures state that these times should be less than 90 minutes, but evaluations of hospital performance indicate that more than half of patients with STEMI experience longer waits. Moreover, patients who are transferred from one hospital to another for emergency angioplasty seldom have total door-to-balloon times of less than 90 minutes.

Given these problems, a key question is whether there is a clear threshold after which rapid administration of fibrinolytic therapy becomes a better strategy than angioplasty. Studies suggest that if it takes more than 90 to 120 minutes longer to provide angioplasty than fibrinolytic therapy, then fibrinolytic therapy is preferred. Some experts have also suggested that we might tolerate slightly longer delays for certain subgroups who may derive greater benefit from angioplasty than others, such as those in shock; but time still matters.

Researchers, institutions, and individual teams are focusing substantial effort on ways to improve door-to-balloon times. Recent studies have identified several key, underutilized strategies that are associated with faster times. These simple and inexpensive strategies include having the emergency medicine physician activate the catheterization laboratory, having activation require only a single call, setting the expectation that the catheterization laboratory team be ready within 20 to 30 minutes of the call, and implementing a system for rapid data feedback about cases in progress. Currently, a national initiative called the D2B: An Alliance for Quality, developed by the American College of Cardiology and supported by 38 other partners including the American Heart Association, is promoting the adoption of these strategies with a goal to perform 75% of primary angioplasties in 90 minutes or less. More than 900 U.S. hospitals are enrolled in this effort, and an evaluation of the program will occur next spring. Anecdotal reports are suggesting that improvement is occurring in many hospitals throughout the country.

The challenge now is for every hospital to achieve the goal of treating at least 75% of patients with STEMI within 90 minutes or less. The D2B Alliance is making a final push for all to reach this goal by the end of the year. This effort is showing how to translate information about best practices into everyday practice, transforming what was once extraordinary performance into routine care.

— Harlan M. Krumholz, MD, SM

Published in Journal Watch Cardiology October 17, 2007