Home Cardiac Care Strategies to steer clear of trouble managing acute coronary syndrome

Strategies to steer clear of trouble managing acute coronary syndrome

March 2006

Published in the March 2006 issue of Today’s Hospitalist

The patient presents to the ER with chest pain consistent with cardiac pain and EKG changes, but his biomarkers do not appear to be elevated. After examining the patient, you suspect the cause may be acute coronary syndrome (ACS), but you’re not sure. How should you proceed?

As hospital medicine makes a name for itself as the go-to specialty, cardiologists are asking hospitalists to take on more and more responsibility for triaging ACS patients. That trend is putting hospitalists in the sometimes uncomfortable position of deciding whether to admit patients that may have acute coronary syndrome and begin treatment, or to send them home for later follow-up.

That responsibility is also raising two other types of concerns. The first, and probably most important worry revolves around liability: Will hospitalists who diagnose and treat an ACS patient, some wonder, be faulted for not calling a cardiologist quickly enough if something goes wrong?

The second concern focuses not on legal issues, but reimbursement. With payers like Medicare already benchmarking hospitals based on how well they care for ACS patients, it’s only a matter of time before they start measuring “and reimbursing “physicians using those same measures.

While these are legitimate concerns, there is help for hospitalists in the form of widely endorsed guidelines released several years ago by the American College of Cardiology and American Heart Association. According to Debabrata Mukherjee, MD, these guidelines can not only help physicians reduce morbidity and mortality in their ACS patients, but steer clear of problems with liability and performance measures as well.

At last year’s Fall 2005 Hospitalist CME Series, Dr. Mukherjee reviewed how hospitalists can use the ACC/AHA guidelines to diagnose and treat patients they suspect of having acute coronary syndrome. Here’s a recap of the advice he offered hospitalists.

High-risk patients

Dr. Mukherjee, professor of interventional cardiology at the University of Kentucky, said that the ACC/AHA guidelines provide strong evidence on diagnosing and treating acute coronary syndrome. First and foremost, he said, is determining the patient’s acute coronary syndrome risk level.

While many symptoms will help you confirm a diagnosis of acute coronary syndrome, Dr. Mukherjee urged physicians to look for two key factors: heart failure and elevated enzymes. “If patients have heart failure symptoms, crackles and rales in their lungs, a new onset mitral regurgitation murmur, hypotension or elevated biomarkers,” he explained, “you’ll know they are high-risk patients without looking at anything else.”

If the patient is high-risk, Dr. Mukherjee added, you need to determine whether ST elevation is present. A convincing body of evidence says that patients who have ST elevation need to go to the cath lab within 90 minutes for reperfusion. (If that is not an option, he said, go ahead and thrombolyse the patient.)

When working with high-risk ACS patients, and not just those with ST elevation, the guidelines call for invasive therapy. The guidelines provide a long of symptoms that should trigger a visit to the cath lab, including recurrent ischemia despite medical therapy and elevated biomarkers.

Dr. Mukherjee said that if patients have even one of the symptoms on the list, the guidelines call for an invasive strategy. (For a full list of signs that should tell you a patient is high-risk, see “High-risk ACS patients: a list of candidates for invasive therapy” left.)

When working with high-risk ACS patients, however, Dr. Mukherjee noted that hospitalists should consider getting help. “It’s probably a good time to go ahead and check with the cardiologist,” he said.

Low- and moderate-risk patients

When patients are not high-risk “their EKG and biomarkers are relatively normal “you can admit them to your service or put them in an observation unit, if your hospital has one. The goal, Dr. Mukherjee said, is to get a repeat EKG and cardiac marker measurement six to 12 hours after the onset of symptoms.

“You do not want to rule out an MI on a single EKG or a single blood test,” he explained. “You need a repeat EKG or repeat biomarkers at six to 12 hours. If patients have recurrent pain or if the second troponin comes back positive, they obviously need to be admitted.”

If your patient is truly low- to moderate-risk and has no contraindications to revascularization, the guidelines call for either invasive or conservative therapy. While many of the medical therapies recommended by the guidelines may seem basic “giving these patients aspirin, for example “they still bear repeating because they’re not always followed.

(For more recommendations on the guidelines for medical management, see “A review of medical approaches to acute coronary syndrome” below.)

Dr. Mukherjee pointed out that only about 90 percent of ACS patients receive aspirin, despite extensive data showing that the drug reduces the risk of a patient dying in the hospital or having a reinfarction by about 50 percent.

In addition, some of the recommendations urge physicians not to use certain drugs. While GP IIb/IIIa inhibitors were widely used to treat ACS patients as recently as 10 years ago, for example, Dr. Mukherjee said the evidence now shows that these drugs don’t provide as good a risk reduction as other therapies. As a result, they are no longer recommended for all ACS patients, but individuals who show positive biomarkers and need to go to the cath lab.

Dr. Mukherjee also pointed to another recommendation in the guidelines that not all physicians know about: Consider any individual with diabetes, even if they don’t have other ACS risk factors, as intermediate risk of having ACS.

Clearing low-risk patients

If your patient appears to be low-risk for ACS, how do you proceed? You may be leery of sending the patient home, but you don’t want to unnecessarily admit patients.

“If there is no recurrent pain,” Dr. Mukherjee said, “the patient has negative follow-up studies, a negative EKG and negative troponin at 48 hours, you can either do a stress test in the hospital, or very soon afterward as an outpatient to look at their LV for ischemia.”

He explained that the guidelines say that if two sets of EKGs and two sets of enzymes are negative, it’s not necessary to do a stress test in the hospital. He was just as quick to warn, however, that sending the patient home without any follow-up is the wrong approach.

“You cannot send patients home and simply tell them that they need to follow up with someone else,” Dr. Mukherjee said. “If you are going to send someone home without a stress test, make sure the patient has a name and number of a physician and that an appointment has been set.”

“You need to document that the patient has an appointment with Dr. X on such and such a date, the patient knows it and it’s in writing,” he added. “Only then are you protected from liability.”

What about the patient who repeatedly presents with signs of ACS, like the individual who has been to the hospital three to four times over the last six months complaining of chest pain but consistently has a negative EKG, negative biomarkers and a negative stress test? Dr. Mukherjee said that the guidelines recommend early invasive strategies for these individuals, even if they don’t have any high-risk features of ongoing ischemia.

He added that catheterizing these patients provides tremendous “reassurance value,” even if you find that their arteries are clear. “If you cath them, and you explain that they are normal and that’s not going to change in four or five years,” he explained, “those patients will not come back the next time as soon as they have musculoskeletal chest pain.”

Coping with ambiguity

While Dr. Mukherjee said the ACC/AHA guidelines provide a good starting point to manage ACS patients, he acknowledged that many of the patients who present with signs of the disease are not clearly high- or low-risk. That ambiguity in diagnosing ACS patients clearly made some hospitalists at the meeting nervous.

One hospitalist described how the cardiologists at her institution are asking hospitalists to take on primary responsibility for diagnosing and treating many ACS patients. She sometimes wonders exactly when she should call for a cardiology consult, and if she is increasing her liability by treating patients who could benefit from the expertise of a cardiologist.

Dr. Mukherjee responded that the ACC/AHA guidelines can play an important role in protecting the physicians who use them. “If you follow the recommendations in the current guidelines and consult a cardiologist for high-risk patients,” he said, “I think that’s very acceptable.”

Liability considerations aside, Dr. Mukherjee added, hospitalists have a strong financial incentive to follow the guidelines: They are already being used to benchmark hospital performance, and it’s only a matter of time before they affect physician reimbursement.

“How hospitals are paid will depend on how well we are adhering to these guidelines for managing patients with acute coronary syndrome,” he said, “so you need to be aware of them. Somebody at some point is going to check whether you are following the guidelines, and your reimbursement will vary depending on how well you adhered to them.”

Edward Doyle is Editor of Today’s Hospitalist.

A review of medical approaches to acute coronary syndrome

When it comes to treating lowand moderate-risk cases of acute coronary syndrome, many of the medical approaches listed in the guidelines from the American College of Cardiology and American Heart Association will come as little surprise. But as Debabrata Mukherjee, MD, pointed out, the adoption of many of these strategies is far from universal.

Here’s a review of medical therapies for ACS that are most applicable to hospitalists:

“¢ Aspirin. Everyone knows the data showing that aspirin is one of the most effective and simple treatments for patients with acute coronary syndrome ” the drug reduces the risk of patients dying in the hospital or having a reinfarction by about 50 percent “but it is not universally used. With Medicare taking note of hospitals that don’t give aspirin to 98 percent of their ACS patients, that may change. If patients have a true contraindication to aspirin “anaphylaxis or a severe reaction, for example “the guidelines call for clopidogrel instead.

“¢ Aspirin and clopidogrel. Because aspirin inhibits only one platelet antagonist, the guidelines call for dual antiplatelet therapy for up to one month after hospitalization. Researchers have found that the combination reduces risk by 20 percent.

“¢ Antithrombotic agents. While there are many new types of antithrombotic agents on the horizon, Dr. Mukherjee said that heparin works as well as anything else. It produces a 30 percent risk reduction in ACS patients.

While some trials where patients were primarily treated conservatively have produced evidence that enoxaparin is more effective than unfractionated heparin, he noted that U.S. trials where most patients are treated invasively have shown essentially no difference between unfractionated heparin and enoxaparin, and that the drug has been associated with some increased bleeding. However, enoxaparin is easier to use and does not require monitoring, and the current guidelines recommend enoxaparin as a preferred alternative.

“¢ ACE inhibitors. The ACC/AHA guidelines recommend ACE inhibitors, particularly for ACS patients who have hypertension, heart failure or diabetes.

“¢ Beta-blockers. This class of drugs, which Dr. Mukherjee described as one of the most effective anti-ischemic therapies available, produces a 20 percent reduction in mortality and major adverse cardiac events. He added that physicians need to use beta-blockers judiciously and avoid using the drug in patients with heart failure and advanced heart blockage.

“¢ Calcium channel blockers. Dr. Mukherjee said that calcium channel blockers should be used to treat ACS patients only if betablockers are contraindicated. The drugs are also recommended for patients who have recurrent chest pain while they are taking nitrates and beta-blockers.

“¢ Statins. Recent research found that an intensive course of lipid lowering therapy ” an 80 mg dose “produced an 18 percent risk reduction. Dr. Mukherjee said that the lesson is that statins are effective, and that higher doses of the more potent statins are better.

“¢ GP IIb/IIIa inhibitors. While this drug was widely used 10 years ago, Dr. Mukherjee said, it offers only a modest reduction in risk and increases bleeding risks. The guidelines note that two groups of patients, however, will benefit from GP IIb/IIIa inhibitors: patients who show positive troponins or biomarkers, and those who need to go to the cath lab.

A cumulative effect

Combining four of the above strategies ” aspirin, statins, beta-blockers and ACE inhibitors “can achieve a 90 percent reduction in mortality. “If you use all four drugs together,” Dr. Mukherjee said, “you get a marked synergistic benefit.”

He also predicted that payers are going to add more of these drugs to their performance measurements.

“Right now, we are using aspirin and beta-blockers as benchmarks in patients with acute coronary syndrome,” Dr. Mukherjee explained. “Eventually, statins and ACE inhibitors will also be used as benchmarks. If you use these four therapies, your patients are going to live longer.”

Clopidogrel before reperfusion: How much, and in what setting?

While clinical practice guidelines offer recommendations on diagnosing and treating patients with acute coronary syndrome, they are largely silent on a topic that’s gaining popularity among cardiologists: giving patients about to undergo reperfusion a loading dose of clopidogrel.

Clopidogrel has been found effective as part of dual-antiplatelet therapy, but cardiologists are now giving it to patients well before they head to the cath lab for reperfusion. At the Fall 2005 Hospitalist CME Series, several hospitalists wondered whether giving patients 300 mg and 600 mg doses of the drug, particularly while they’re still in the ER, is supported by the evidence.

Debabrata Mukherjee, MD, professor of interventional cardiology at the University of Kentucky, explained that while guidelines from the American College of Cardiology and the American Heart Association do not say whether patients should receive the drug in the emergency room, various studies support the strategy.

At his hospital, for example, patients headed to the cath lab receive a 600 mg loading dose of clopidogrel, either before they reach the lab or once they arrive in the lab. He noted that in Europe, physicians tend to go even further and use a 900 mg loading dose based on one study over there.

“Certainly most patients benefit from giving a loading dose of Plavix early on,” Dr. Mukherjee said. “The only downside is that patients who subsequently go for bypass surgery will have increased bleeding.”

While bleeding is a possibility, he added that the number of ACS patients who will need emergent bypass surgery is fairly low, less than 5 percent. “I think it’s a good idea to go ahead and load Plavix early on,” he said. “That will benefit 95 percent of your patients who are treated medically or receive angioplasty.”

Dr. Mukherjee also added that he expects the next generation of practice guidelines to address the use of loading doses of clopidogrel before perfusion.