Even though echocardiography has been the most widely-used diagnostic test for heart disease for more than 50 years, it’s more than keeping up with, even exceeding the benefits of, other imaging modalities. With better resolution than MR and CT, powerful and portable devices, and new research and theories, the echocardiogram is poised to take a starring role in screening and diagnosing heart disease.
Echo for annual exams
John Postley, MD, a cardiologist with New York Physicians Group, performs more than 2,000 echocardiograms a year using the handheld MicroMaxx from SonoSite. Postley recently presented his findings that vascular ultrasound screening can be a more accurate means of risk stratification for heart attack, particularly among women, than the Framingham Risk Score, which has been the traditional method of identifying cardiovascular risk. He used the device to look for the presence of carotid and femoral arterial plaque and the measurement of carotid intimal medial thickness (CIMT).
“We’ve been struggling with what is the relationship between plaque and CIMT,” he says. One thought was that a lower CIMT measurement is the first stage of developing plaque. Research has shown that they are probably separate problems, however. Regardless, clinicians can use echo to analyze both.
Since 800,000 Americans have a first heart attack each year and 40 percent die, 250,000 people are dying without even knowing they were sick, Postley says. He advocates making screening echocardiograms part of annual exams, especially because of the superior resolution offered. “The limit of resolution of MR and CT is no better than 1.5 or two millimeters.” Echo is 10 times more subtle, allowing clinicians to catch much more when it comes to changes and abnormalities.
Supporting Postley’s recommendation is the recent CAFES-CAVE Italian study, which found that looking at CIMT in the four carotid and femoral arteries, outside of the heart, predicts with 98.5 percent sensitivity who will have a heart attack or stroke. “You’re better off looking outside of the heart if you have the technical expertise,” he says. He has that expertise: with the SonoSite MicroMaxx, Postley can look at those four vessels “with astounding resolution” in 14 minutes.
Postley acknowledges the “turf war” that many radiologists and cardiologists experience. “We’re not pretending to be radiologists,” he says. “We can be good partners with radiologists.” If Postley finds a problem via echo, “I immediately refer patients for another study, usually MR or contrast CT, to work out the abnormality.”
Stat in the ICU
Yanick Beaulieu, MD, of the Division of Cardiology and Critical Care Medicine at Hôpital Sacré-Coeur de Montréal, is using handheld, portable echocardiography from SonoSite at the bedside in the intensive care unit. “It’s an important place for echo,” he says. “Every day there’s a situation that dictates an emergent or semi-urgent echo in the ICU.”
As an intensivist and cardiologist, Beaulieu splits his time between the ICU and his cardiology practice. There are different indications for echo in the ICU. Either a patient isn’t doing well from the start or starts to decline, usually because of low blood pressure. There are many causes for that and Beaulieau points out that knowing whether the cause is heart-related or not is a big help. An echocardiogram can quickly show him if there is fluid around the heart, whether the patient has had a heart attack, or whether a pulmonary embolism or other problem with the lungs is straining the heart.
About four years ago, Beaulieu was doing his critical care fellowship when the program’s director purchased a handheld unit. He found the device “addictive.” He has found that patients in ICU or emergency departments “have all kinds of pathologies and a physical exam is not always helpful. We need more information that cannot be provided by physical examination.”
The handheld unit isn’t meant to do everything a larger device can — it’s really a screening tool, Beaulieu says. His hospital has three MicroMaxx devices. Other clinicians and residents use one in the ICU to screen the heart for right and left side function, and putting in lines and drains. A device in the OR assists surgeons with central line access and regional nerve blocks.
Quick EF and volumes
Navin Nanda, MD, professor of medicine and director of the Heart Station/Echocardiography Laboratories at the University of Alabama at Birmingham, recently received an upgrade