How Will Speckle Tracking Transform Cardiac Ultrasound?
Researchers are using speckle tracking imaging in heart ultrasound to monitor the health of transplant acceptance, and clinicians are redefining how to predict and classify the risk of a heart attack among women. These are some of the hot topics being presented at the 19th Annual Scientific Sessions of the American Society of Echocardiography (ASE), June 7-11, in Toronto.
To find out how these findings will impact the use of ultrasound technology and the practice of cardiology, Diagnostic and Invasive Cardiology spoke with Judy R. Mangion, M.D., FACC, FASE, FAHA, Brigham and Women’s Hospital Division of Cardiology.
Diagnostic and Invasive Cardiology (DAIC): New research shows that heart ultrasound technology can be very effective in monitoring heart transplant acceptance as traditional post-operation biopsies, and that the less invasive procedure is not as stressful on the patient’s new heart. How do you anticipate these findings may affect monitoring of heart transplant patients?
Dr. Mangion: Investigators from Korea are presenting data at ASE’s Scientific Sessions showing new highly sensitive and specific heart ultrasound technology called speckle tracking imaging. Traditionally patients who have undergone heart transplants are frequently subject to routine follow-up invasive endomyocardial biopsies to monitor the potential for rejection of that transplant. This particular study looked at 17 consecutive heart transplant patients who underwent a total of 42 routine follow-up endomyocardial biopsies. They looked at the new revolutionary ultrasound technology called speckle tracking to measure peak systolic longitudinal strain (PSLS) and they correlated decreases in PSLS, especially PSLS of mid and apical segments . They were able to detect early evidence of subclinical acute allograft rejection after heart transplant in these patients with a sensitivity and specificity of 78 percent. It’s a pretty high sensitivity and specificity with which this speckle tracking technology measured PSLS correlated with the traditional invasive endomyocardial biopsy.
DAIC: If this technology is widely adopted, how would that change standard follow-up protocol for transplant patients?
Dr. Mangion: It would improve the quality of life for many heart transplant patients who have to come in every year, sometimes more frequently, for myocardial biopsy. These patients could avoid the potential risks of the invasive procedure including perforation of the myocardium and damage to the tricuspid leaflets. These endomyocardial biopsies are performed by placing a bioptome in the right heart and taking a piece of the heart muscle within the right ventricle. If we know that we have the technology that 80 percent of the time is able to pick up subclinical rejection, we have a noninvasive method of intervening early, diagnosing early rejection and treating rejection before it becomes more dangerous to the patient.
Large academic echo labs are using speckle tracking, but mostly for research purposes. Many of the large academic echo labs have this technology installed on their ultrasound machines. It is starting to be used more and more both clinically and for research purposes. I suspect as people become more familiar with it, it will be used even more. For example, technology that just came out 10 years ago, such as tissue Doppler is routinely used nowadays, and I suspect the same pattern will happen when it comes to speckle tracking as people become more familiar with it. It is not more difficult to perform than any of the other Doppler techniques we regularly use. Getting the word out to the clinicians that this technology has benefits over older technologies is really going to be the key to its more widespread utilization.
DAIC: Is there a need for further research on speckle tracking technology as it is used for diagnosing rejection in heart transplant patients?
Dr. Mangion: I suspect the heart transplant people would want to see further research in the area of transplant rejection, but in terms of this speckle tracking technology, there is a lot of research that has been published in the last year or so in the area of heart muscle dysfunction, particularly research using speckle tracking for identifying genetic cardiomyopathies. GE, Philips and Siemens all offer speckle tracking imaging within their line of ultrasound systems.
DAIC: A new method to predict and classify the risk of a heart attack among women was presented in an abstract by Farooq Chaudhry, et al. How could these findings impact the current protocol for women presenting with chest pain?
Dr. Mangion: This study on stress echocardiography in women with atypical chest pain is an important presentation of research from St. Luke’s Hospital in NYC. The study investigates stress echo and its roll in predicting and classifying the risk of myocardial infarction and cardiac death in women presenting with atypical chest pain.
This study is very important because women present differently from men when they have chest pain symptoms. Their symptomotology is not the typical substernal chest pressure radiating down the left arm associated with nausea and vomiting. Their chest pain can be very unusual. So traditionally it’s been very difficult to diagnose heart disease in women. And women unlike men are at high risk for false positive EKG stress tests – those are stress tests where the EKG is monitored alone, without using any type of imaging modality in addition to the EKG.
This was a large study in which 1,375 consecutive women with atypical chest pain were referred for stress echocardiography. They were able to very effectively risk stratify this large cohort of patients into patients who were low risk for coronary artery disease versus patients, who despite their atypical symptoms, were really at high risk for coronary artery disease.
The conclusion of the study is that women, even women who present with unusual symptoms of chest pain would do well if they underwent stress echo as oppose to plain EKG stress testing.
DAIC: Do you think this is a protocol that could be adopted in the ER for women presenting with atypical chest pain?
Dr. Mangion: I do, and I think that physicians should be aware that if they have women who are presenting with symptoms of atypical chest pain, if they were to just refer these women for typical EKG stress testing, they could potentially over diagnose or even overlook serious problems without the aid of stress echocardiogram.
The word needs to get out to referring physicians because there are still many women who present to their doctors with chest pain, who are either overlooked entirely or who are just getting referred for plain EKG stress testing. Part of the reason is that physicians feel that the chest pain is not likely to be something serious. They think it is unusual. So, they appear to be missing patients who do have significant coronary artery disease.