This story has almost disappeared without a trace. That’s because it defies conventional wisdom. Doctors do not know what to do when data do not support strongly held beliefs.
The New England Journal of Medicine published an important study on September 5, 2013, titled “Door-to-Balloon Time and Mortality Among Patients Undergoing Primary PCI.” In a nutshell, deaths due to heart attacks have not been reduced despite faster clot busting strategies.
Here’s the story behind the headlines. A heart attack is generally thought to be caused by a blood clot that lodges in a coronary artery, cutting off blood flow to heart tissue. This can lead to cellular damage, irregular heart rhythms and death. The goal of modern-day treatment has been to open blocked arteries as quickly as possible and to restore blood flow and prevent further tissue damage. It seems totally logical.
Interventional cardiologists have been pushing to speed up this process because of the absolute belief that minutes matter. They assess their success by measuring “door-to-balloon” or D2B time, meaning the time from entrance into the hospital to actual insertion of the catheter that contains a small balloon. When the balloon is inflated it is supposed to open the blocked artery through a procedure called PCI (primary coronary intervention, aka angioplasty). Pressure to shorten D2B time has been intense and hospitals congratulate themselves when they make progress shortening the amount of time it takes to get a patient from the ER into the cath lab and open the clogged artery.
Here’s the rub. In the just-published study, researchers analyzed data from 96,738 heart attack patients undergoing angioplasty between 2005 and 2009. These are big numbers and very revealing.
Between July 2005 and June 2006 the door to balloon time across 515 hospitals was 83 minutes. Between July 2008 and June 2009 that time dropped significantly to 67 minutes. That may not seem like much to a layman, but trust us when we tell you that it is a substantial improvement. Hospitals are really humping to accomplish that kind of reduced D2B time.
Perhaps even more impressive is the statistic that 83.1% of hospitals reduced door-to-balloon times to 90 minutes or less (a major goal) by the end of the study compared to only 59.7% of the hospital at the beginning of the study. By all accounts, the grand operation (in the fullest sense of that word) was a success. The trouble is the patients still died at the same rate. There was no improvement in outcome. The same number of patients died at the end of the study as at the beginning, despite faster angioplasty procedures.
What went wrong? No one seems to have a good answer. Here is what the authors conclude with regard to their research. Their “findings raise questions about the role of door-to-balloon time as a principal focus for performance measurement and public reports,” and “suggest that additional strategies are needed to reduce in-hospital mortality in this population.”
You have to understand that the commitment to reduce D2B times was extraordinary. To accomplish a goal of under 90 minutes, or better yet, 67 minutes, took incredible resources and effort by dedicated teams of health professionals. It comes as a tremendous shock to learn that this super-human effort didn’t pay off in reduced mortality.
This isn’t the first time that primary coronary intervention (angioplasty with a stent) has produced unexpected results. A study published in the New England Journal of Medicine (April 12, 2007) rattled the cardiology community to its core. The COURAGE trial (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) pitted stents against drug therapy and lifestyle changes.
The 2,287 patients who participated in this study all had chest pain on physical exertion, what doctors call stable coronary artery disease. They presumably also had some clogging of their coronary arteries. Roughly half were randomized to receive angioplasty and stents plus drugs and lifestyle recommendations. The other half just got medication, diet recommendations and exercise coaching. To the shock of interventional cardiologists (who perform angioplasties), there was no measurable difference between the two groups after five years when it came to heart attacks, strokes or deaths.
Angioplasty costs about $30,000. The medications (which are mostly available generically) are inexpensive and should cost less than $500 a year.
The core of the problem with angioplasty and stenting is that cardiologists have sold this procedure as a plumbing problem. They perform an angiogram in which dye is squirted into the heart so that the arteries can be seen in graphic detail. If there is a blockage it looks dramatic. That is why George Bush had stent surgery this summer. Although he had no chest pain or shortness of breath and was in great shape, an exercise stress test suggested trouble. That led to heart imaging and signs of blockage and that led to angioplasty and a stent.
We won’t enter the controversy over whether this was a life-saving procedure or an overreaction. What we can say is that most patients believe getting a stent will prevent a future heart attack. There are no data to support that belief. Angioplasty and stents can often ease chest pain (if it exists). The COURAGE trial demonstrated that this procedure doesn’t necessarily save lives or prevent heart attacks or strokes.
That’s in part because the blockage that can be seen on an angiogram may not be the demon we once thought. Some cardiologists now believe that it is invisible plaque inside the wall of the artery that may be most vulnerable. When this ruptures, it spills inflammatory proteins into the artery that creates a blood clot and a heart attack.
We are not therapeutic nihilists. Anyone who suspects he is having a heart attack should immediately call 911 and get to an emergency department for evaluation and treatment. But the new study is a wakeup call that a speedy angioplasty and stenting procedure is not necessarily the magic bullet we all were led to believe. There may be other factors, as yet unidentified, that will make surviving a heart attack more successful.
Of course we prefer prevention, but that too remains controversial. There are many physicians who believe that statin-type drugs are the best way to prevent a heart attack or a stroke despite a meta-analysis of clinical trials suggesting that such drugs are not very good for accomplishing this in otherwise healthy people. Here is a link to this research.
We think diet can often be as effective as medications. To read about this controversy in more detail so you can decide for yourself, here is a link.
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