On the front lines of aortic dissection

A leading cardiologist explains why hospitalists are key to improving long-term outcomes.

Hospitalists are ideally placed to improve long-term outcomes in patients with aortic dissection, but first they need to know how to recognize the disorder. The best place to look for risk is in the patient's history, advised a presenter at Hospital Medicine 2009.

“Lesson No. 1 that I want you to take home: Patients who've had prior heart surgery are at higher risk for aortic dissection,” Kim A. Eagle, MD, director of the University of Michigan Cardiovascular Center, told attendees. “Also remember that we cause aortic dissection in 5% of the cases. If you're called to see a patient after a cardiac surgical procedure or catheter-based procedure in the aorta and the patient has findings that suggest possible acute dissection, think iatrogenic dissection. That happens, and it can happen in your hospital.”

Patients with bicuspid aortic valve disease are also at high risk for aortic dissection, Dr. Eagle said. “Imprint in your mind: When you see bicuspid aortic valve disease, think aorta,” he said. “These patients are often missed. Furthermore, I want you to think of their children and their relatives, because if they have a bicuspid aortic valve, 9% of their descendants will have bicuspid aortic valve and another group will have other congenital heart defects.”

Crippling pain a telltale sign

Hospitalists may think they don't have to worry about diagnosing aortic dissection because it will be caught in the emergency department. Wrong, Dr. Eagle said. “Over half the time, [the patient has] been admitted to you and nobody knew what the diagnosis was because they thought it was an acute coronary syndrome, or ‘acute chest pain, rule out MI’.”

Abrupt, crippling pain is a common symptom of aortic dissection, reported in 85% of patients, Dr. Eagle said. Unlike patients with acute coronary syndromes, who often describe a general uneasiness and chest discomfort, dissection patients usually have a photographic memory of what they were doing the moment their pain began, Dr. Eagle said.

“The other thing about this pain is it can go away,” he noted, “so do not be misled to thinking this patient is stable if their horrific sudden-onset pain went away. It's a ticking time bomb, and it will blow, and it often blows soon.”

Twenty-eight percent of patients with aortic dissection present with acute abdominal pain rather than thoracic pain, Dr. Eagle said. On physical exam, 30% of patients have a murmur of aortic valve insufficiency and about 25% have a pulse deficit.

“If they record a differential blood pressure, look out. That could be a dissection,” he said.

He warned attendees not to be reassured by normal chest X-rays, which can be found in 15% of patients with aortic dissection. Physicians may also have been taught that the EKG will be normal, but that's not true, Dr. Eagle said.

“The EKG in acute dissection is often not normal and it may lead you to think about ischemic heart disease, but most MIs don't present with catastrophic sudden onset of discomfort of the chest going to the back,” he noted. “So you have to use the history to try to tease out [the correct diagnosis]. You have to find those cases.”

As for biomarkers, Dr. Eagle recommends d-dimer for diagnosis. “d-dimer is up in 97% of acute aortic dissections, and we should be using it,” he said. Most dissections will have a d-dimer level above 500, and a d-dimer level above 1600 ng/mL is likely to indicate a pulmonary embolism or an aortic dissection, according to Dr. Eagle.

“If you have a patient with atypical symptoms, a normal troponin, and a high d-dimer, I want you to focus on PE and dissection. It could be either one. I want to see us using d-dimer as one of our biomarkers in acute aortic syndromes,” he said.

When it comes to testing for aortic dissection, Dr. Eagle reminded his audience that quickness counts. “Time is life with dissection, so speed is everything,” he said.

Often, however, the first study won't tell you what you need to know. “Most patients with dissection need two or sometimes three tests to either make the diagnosis and plan therapy,” he noted. Computed tomography (CT) is the most commonly used test, followed by echocardiography. Aortograms and MRIs are less common because they're less available or they're too invasive, Dr. Eagle said.

“One patient out of 20, the first test will miss it. So if you're sure that this sounds like a dissection, that is your best diagnosis, get another test. Don't stop if you really think this sounds like the right story,” he said.

A disease for life

Hospitalists need to stress to patients that aortic dissection is a disease for life, Dr. Eagle said. Survival rates after treatment for aortic dissection are poor in the first year because many patients are lost to good follow-up.

“Our handoffs are terrible,” Dr. Eagle said. “[Patients] don't know that they have to get their medicines when they run out, that they've got to get follow-up imaging. We haven't told them. We've told them how great we are saving them from this dreaded disease, and then they go home and they rupture alone. We can't do that. We've got to attack.”

Beta-blockers are the mainstay of therapy, despite a lack of randomized, controlled trials, Dr. Eagle said. He also recommended angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in addition to beta-blockers, based in part on the results of the Jikei Heart Study, and said that statins are indicated in patients with atherosclerosis.

Over the long term, patients who've had aortic dissection should aim for a heart rate less than 60 beats per minute. Blood pressure should be controlled to less than 120/80 mm Hg, or “as low as you can get it and not have hypoperfusion symptoms,” Dr. Eagle said. Clinicians should order imaging studies to watch for aneurysm formation one, three, six and 12 months after the initial event. “The first year after dissection is the most important year of life,” he said.

Dr. Eagle urged attendees to educate their patients and let them know what they are up against. Patients should be told to avoid lifting more than 30 or 40 pounds and should not play contact sports, such as soccer or football, he said. They should know to seek urgent medical help if they have any sudden onset of pain in their chest, back or abdomen, Dr. Eagle noted, and should tell medical personnel about their previous dissection. Also, they need to understand that their medications are vital to their survival. “When they run out of medicines, they are threatening their lives,” he said. “So they can't run out of their medicines.”