The critical month: managing patients after heart attack
By Gina Shaw
Internist David L. Fried, ACP Member, vividly recalls a patient he treated some years back who survived a heart attack—with a left ventricular ejection fraction (LVEF) of only 15%.
"He was on maximal medications, and his cardiologist and I worked together to watch him very closely, constantly adjusting his medications," said Dr. Fried, a general internist in Cranston, R.I. While the patient ultimately succumbed to cardiovascular disease, Dr. Fried recalled, he did live several years after the initial infarction. "He absolutely would not have survived that long without aggressive management."
A recent study has underscored the need for "aggressive management," particularly in the first month post-MI. An observational study published in the June 23, 2005, issue of New England Journal of Medicine (NEJM) found that heart attack survivors with decreased left ventricular function, heart failure or both face a 30-day window of dramatically increased risk of sudden death.
"The risk during that first month is over 10 times what it is in about a year [post-discharge]," said Scott Solomon, MD, a cardiologist at Boston's Brigham and Women's Hospital who led the research team. "After the first month, we begin to see a dramatic reduction in this risk of sudden death."
The findings may spur renewed research into the effectiveness of different devices designed to help patients avoid sudden death or another cardiac event. And, experts say, study results highlight the need for aggressive use of medications and other interventions.
More research needed
Dr. Solomon's research team used data from the Valsartan in Acute Myocardial Infarction Trial (VALIANT), which between 1998 and 2001 followed more than 14,000 high-risk patients post-MI with left ventricular dysfunction (defined as an ejection fraction of no more than 40%), heart failure or both. (The study abstract is online.)
The team found that during the first 30 days, these patients had a 1.4% risk per month of sudden death overall. (The study defined sudden death as one "that occurred 'suddenly and unexpectedly' in a patient in otherwise stable condition.") Patients whose LVEF was below 30% were found to be in particular danger, with a 2.3% risk of death or cardiac arrest per month during that critical one-month window.
"The patients with the lowest ejection fraction were at greatest risk, which makes sense," Dr. Solomon said, "but surprisingly, even those with somewhat higher ejection fractions were at increased risk of death in that first month."
Of the 14,609 enrolled patients, 1,067 patients, or 7%, had an event 180 days after their myocardial infarction; 903 of them died suddenly. Nineteen percent of all sudden deaths or episodes of cardiac arrest with resuscitation occurred within the first 30 days after the heart attack, while 83% of all patients who died suddenly within the first 30 days did so after discharge.
Clearly, those first 30 days post-discharge for high-risk MI patients are somewhat akin to the "golden hour" of trauma cases: a time when they need to be treated aggressively and watched carefully to buy time until their chances of survival improve. But how do physicians buy patients that time? And what does the study imply for risk assessment and patient management?
"What these data tell us is that we have a challenge, and a period of time in which certain patients are very vulnerable," Dr. Solomon said. Experts say the study findings are a mandate for more research, particularly for different types of what Dr. Solomon calls "bridge protection," getting patients through the first few months post-MI.
One possibility: noninvasive, vest-style defibrillators for high-risk patients. The first wearable defibrillator, the Lifecor LifeVest, got a boost this summer when Medicare expanded its coverage of the LifeVest for the prevention of sudden cardiac death. The new reimbursement policy now covers LifeVest use immediately after an MI in patients with an ejection fraction of less than 36%.
"A study of these vests, focused on high-risk patients, was proposed to the National Institutes of Health [NIH] a number of years ago, but not funded," said Kenneth Ellenbogen, MD, professor of medicine at the Virginia Commonwealth School of Medicine in Richmond, Va., and spokesperson for the American Heart Association. "But now, looking at these results, it's the ideal type of study to do with these patients."
Another potentially lifesaving intervention could be sending automatic external defibrillators (AEDs) home with high-risk patients, along with instructions for family members on how to use the device. The NIH is already sponsoring a study of this approach, led by the Seattle Institute for Cardiac Research, which is expected to conclude in 2007.
"The utilization of home AEDs should definitely be looked at," said Howard Weitz, FACP, vice chair of the department of medicine at Jefferson Medical College in Philadelphia and co-director of the Jefferson Heart Institute. "But we should also look at when in the one-month period the sudden deaths occur, and how recently the patients were discharged. It may be a matter of prolonging hospitalization for some in the highest-risk group, but research is needed to determine the identifying characteristics of that group."
According to Dr. Solomon, however, while the increased risk of sudden death drops every day post-MI, risk does extend more than just a few days out from discharge.
"It's true that we've been sending patients home from hospital earlier and earlier after infarction, and there's probably a balance we have to achieve," he said. "But we've not yet precisely identified the optimal time period for hospitalization." A study in the April 12, 2004, issue of Archives of Internal Medicine noted that the overall average length of hospital stay after an acute MI declined from 11.7 days in the late 1980s to 5.9 days between 1997 and 1999.
The NEJM study findings also raise questions about implantable cardiac defibrillator (ICD) use.
Current ST-elevation myocardial infarction guidelines from the American College of Cardiology-American Heart Association (ACC/AHA) recommend that ICDs be implanted no sooner than one month after an MI in high-risk patients. (According to the NEJM study, Medicare will not pay for implanting ICDs in these patients before 40 days post-MI).
Should the ACC/AHA recommendation be revisited?
That depends on who you ask. Results published in 2004 from the Defibrillator In Acute Myocardial Infarction Trial (DINAMIT) found that implanting these devices six to 40 days post-MI for patients with an LVEF of 35% or less didn't reduce the risk of death. (The DINAMIT study abstract is online.)
But others suggest that perhaps DINAMIT isn't the last word on the subject.
"The editorial accompanying the [VALIANT NEJM] study made the point that we might need to look again at ICDs in these patients, and perhaps study the type used more specifically," said the AHA's Dr. Ellenbogen. "There's some concern that if you put in an ICD and let it pace the heart, it could actually cause heart failure. Perhaps the solution would be the type of defibrillator that doesn't pace, or one that paces both ventricles."
At the same time, Dr. Ellenbogen said, the ACC/AHA guideline on ICDs may be updated in the future. "We use 35% as the cutoff for ICD implantation after one month in the current guidelines," he said, "but the risk is still relatively high for those with an LVEF of 35% to 40%. That cutoff point may be reconsidered in the future, based on that data, particularly in that high-risk window of one month or so." The full ACC/AHA guidelines are online.
ICDs are also receiving heightened scrutiny in the wake of recent FDA recalls of several ICD models manufactured by Guidant Corporation, as well as an FDA investigation into how the company addressed safety. But Dr. Ellenbogen pointed out that there have been only two patient deaths among the thousands in whom the devices have been implanted.
"These devices save lives," he said, "and it would be a shame if this problem makes people afraid of getting ICDs to prevent a future heart attack."
Mayo Clinic's Raymond Gibbons, MD, president-elect of the American Heart Association and past chair of the ACC/AHA task force on practice guidelines, said he hopes the new VALIANT results spur additional ICD research.
"Because it was negative, DINAMIT reduced the interest in the use of ICDs early after an MI," he pointed out. "Hopefully, this study will put the issue back on everyone's radar screen."
Risk awareness is key
In the meantime, what can physicians do now to manage these high-risk patients?
According to Dr. Gibbons, the first step is to prevent patients from getting this ill in the first place.
'The best data we have suggest that only 70% of patients eligible for thrombolytic therapy or primary PCI during the acute stages of MI get it.'
—Raymond Gibbons, MD
"The best data we have suggest that only 70% of patients eligible for thrombolytic therapy or primary PCI [percutaneous intervention] during the acute stages of MI get it," he said, noting that the NEJM study highlights the importance of that therapy. Of the patients in the VALIANT trial who survived, 49% received thrombolytic therapy or primary PCI, compared with only 31% of patients who died.
And, Dr. Gibbons added, patients in the VALIANT trial who died were much more likely to have had at least one other prior heart attack. Only 24% of the survivors had a prior MI vs. 43% among those who died.
"This wasn't their first heart attack—it was their second or third or fourth," Dr. Gibbons said. "Internists and cardiologists need to work together aggressively to make sure that post-MI patients get all the things we know make a difference in preventing a second infarction, including aspirin, ACE inhibitors and appropriate lipid-lowering therapy."
When a patient does survive an MI with a heavily damaged heart, he continued, the study holds another clear message: the importance of beta-blockers. Of patients who survived, he said, 73% were taking beta-blockers, compared with only 59% of those who died.
Rhode Island's Dr. Fried noted that his patient with an LVEF of only 15% was taking an ACE inhibitor, nitrate, diuretic, beta-blocker and aspirin.
He saw the patient weekly and was in regular phone contact with the visiting nurse to monitor the patient's health. While Dr. Fried said he relies on visiting nurses to help track patients' progress, he also asks family members to serve as extra eyes and ears and he educates patients about cardiac warning signs, such as discomfort and shortness of breath. He also makes sure he is available to appropriately respond to patient calls or questions.
Ultimately, said Dr. Gibbons, the VALIANT study reinforces the urgency of using information already available on reperfusion therapy, medications and secondary prevention.
"It's long been recognized that there's a disconnect between what we know and publish in guidelines, and what happens in practice—and we all need to work hard on reducing that gap," he said. "This study is a dramatic illustration of just why that's so important."
Gina Shaw is a freelance health care writer based in Montclair, N.J.
The information included herein should never be used as a substitute for clinical judgment and does not represent an official position of ACP.
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