For the patients who experience a heart attack caused by a complete blockage of blood supply to the heart (called ST segment elevation myocardial infarction or STEMI), quick response is critical. These patients should be treated with artery-opening procedures soon after they arrive at an emergency room. As a result of the complete blockage of the artery, virtually all the heart muscle being supplied by the affected artery starts to die if the patient is not treated quickly.
In the heart attack care community, the mantra is “time is muscle”, referring to the urgent need to restore the flow of oxygen-rich blood to preserve the heart’s function. A measurement that is also important is the door-to-balloon time (D2B): the time between going through the door of an emergency room to the time a balloon is used in opening the blocked artery (the procedure is called angioplasty).
The American Heart Association (AHA) and American College of Cardiology (ACC) recommend a door-to-balloon time of no more than 90 minutes for STEMI. Thanks to a nationwide concerted effort, the median door-to-balloon time dropped from 96 minutes in 2005 to 64 minutes in 2010. This is a success story in healthcare quality improvement. This is also a excellent example of statistics in action – from identifying the issues and problems, to tracking and measuring progress in improvement. In this instance, statistics helps saves lives.
For angioplasty to be performed in a timely manner for a STEMI heart attack, many things have to fall into place. The staff to perform the procedure needs to arrive on time (preferably within 20-30 minutes). Should angioplasty is determined to be necessary; the catheterization lab needs to be activated (preferably with a single phone call). For the heart attack care unit to be efficient and effective, there has to be strong administrative support and all the personnel have to work with a team mentality. A mechanism for providing real-time feedback, a way for the staff to share experience and to find out what went right and what went wrong, can help the staff make continual improvement.
A study conducted in 2006 set out to identify the problems and issues in the low performing hospitals and the best practices in the high performing hospitals in treating STEMI heart attacks. The strategies described in the previous paragraph are some of the best practices identified in this study. The widespread adoption in these best practices, as a result of a nationwide concerted effort, has led to the marked improvement in STEMI cardiac across the United States.
The most important improvement is on the key quality measure of door-to-balloon time. According to a new study, door-to-balloon time declined from a median of 96 minutes in the year ending December 31, 2005, to a median of 64 minutes in the 3 quarters ending September 30, 2010. This study represents a 5-year follow up. A 4-year follow up published one year earlier also presented a similarly excellent report card.
At Yale-New Haven Hospital recently (a record breaking example), a woman was treated within just 16 minutes, resulting in no damage to her heart muscle. The woman was home in two days and back to work in 10 days.
According to the same new study, the percentage of patients treated under the 90-minute guideline has also increased substantially. The percentage of patients treated with angioplasty within 90 minutes increased from 44.12% in 2005 to 91.4% in 2010. So previously, being treated in a timely manner was more like a coin toss. Now virtually everyone is treated within the AHA/ACC guideline.
Furthermore, the percentage of patients treated within 75 minutes increased from 27.3% in 2005 to 70.4% in 2010. The investigators reported that the declines in median times were greatest among groups that initially had the highest median times: patients older than 75 years of age (median decline, 38 minutes), women (35 minutes), and blacks (42 minutes).
The concerted effort mentioned earlier was coordinated between federal agencies, healthcare organizations and clinicians. The goals are to improve heart attack care and to improve outcome by accelerating treatment. One organization involved is D2B Alliance, which was launched in 2006 by the American College of Cardiology with national partners to improve D2B time by advocating the adoption of best practices shown to reduce delays of care of STEMI.
The excellent report card achieved by these organizations is also a success story of using statistics to solve problems and save lives.