A new technology called “virtual native enhancement” (VNE) may soon eliminate the need for gadolinium as a contrast agent for patients with hypertrophic cardiomyopathy undergoing cardiac MRI. Gadolinium, a heavy metal contrast agent which is injected intravenously, has long been used in cardiac MRI scans to spot cardiac scar tissue in patients with HCM. In 2017, the FDA issued a safety communication relating to gadolinium because it was found that gadolinium remains in the body for months to years after the use of the drug.
The new VNE technology, recently described in the journal Circulation, uses artificial intelligence (AI) to virtually enhance the standard MRI image. The technology was developed using data taken from 1348 HCM patients and was validated in the HCM population, but the technology may have uses extending beyond HCM.
By avoiding the use of the contrast agent, this technology avoids side effects and long term consequences from the use of gadolinium. Additionally, it will make cardiac MRI available to patients who are allergic to gadolinium. VNE is also faster and cheaper that current technology used for cardiac MRI, which may make more frequent MRI monitoring of patients feasible.
To read more about VNE, see also this article in UVA Today, this article in ACM Tech News, this article in Engineering and Technology, and this article in Science Daily.
Researchers in the U.K. have found that 20% of HCM gene carriers who do not show overt signs of HCM do show reduced blood flow to cardiac tissue.
Although the gene positive individuals lacked the characteristic left ventricular wall thickening of HCM, 1 of 5 patients who carried the HCM gene showed marked regional perfusion defects when compared to healthy individuals. Hence, the researchers concluded that a person who is gene positive for the disease may show reduced cardiac perfusion before they develop hypertrophy.
The study compared 50 patients who carried the HCM gene but had no signs of left ventricular hypertrophy to 28 healthy individuals. Both groups underwent Cardiac MRI testing.
The researchers theorize that perfusion mapping may be a useful way to identify HCM gene carriers who will go on to develop the disease.
To read about more early signs of HCM click here
and to read the findings of another study describing reduced cardiac volume in gene positive people, click here
In a recent study, researchers examined whether cardiac MRI results might help predict which patients would would go on to develop atrial fibrillation (AFib) that was serious enough to require hospitalization, require electrical cardioversion or catheter ablation, or identify those patients who might go on to develop permanent AFib.
The study found that the major predictors of these serious AFib consequences in HCM were those who were of older age, those with an increased BMI (this was especially important in patients under age 33), increased left atrial volume index as seen on cardiac MRI (this was especially important in middle-aged patients), reduced left atrial contractile function (this was especially important in middle-age and older patients), and moderate or severe mitral valve regurgitation.
The researchers concluded that using cardiac MRI to measure left atrial volume and contractile function might help medical providers ability to intervene before major AFib develops in HCM patients, specifically by helping patients find ways to reduce their weight and by treating mitral regurgitation and left atrial function more aggressively.
The full paper can be found here and for a summary from Cardiac Rhythm News click here.
The results from the Myokardia EXPLORER- MRI sub-study are in, and there is more positive news for mavacamten (formerly known as MYK-461). According to the results of this small 35 patient study, patients who took mavacamten showed reduction of left ventricular size and wall thickness on MRI. These patients also had a reduction in their left atrial volume. All three of these measurements are predictors of poor outcome for HCM patients Additionally, this study found a reduction in certain biomarkers such as NT-proBNP, which indicate heart stress and injury.
MyoKardia (which was recently acquired by Bristol Myers Squibb) hopes that this drug will be approved by the FDA and available to American HCM patients by the end of this year.
For more on the progress of mavacamten, read these previous entries on HCMBeat:
Positive Results for MyoKardia Drug Mavacamten
MyoKardia Announces Positive Result for Mavacamten for Treatment of HOCM
MyoKardia Announces Positive Results from EXPLORER Trial
More Positive Results for MyoKardia Drug
MyoKardia’s EXPLORER Trial Big Success
DISCLOSURES: CYNTHIA BURSTEIN WALDMAN OF HCMBEAT SERVED AS A PATIENT ADVISOR ON THE STEERING COMMITTEE OF MYOKARDIA’S EXPLORER TRIAL. CYNTHIA ALSO SERVES ON MYOKARDIA’S PATIENT ADVISORY BOARD
According to a recently published study by doctors in Copenhagen, Denmark, myocardial crypts (clefts, cracks or fissures in the myocardium) are found in the general population. Therefore, this article concludes that crypts seen on scans of the heart are not necessarily an indicator of HCM and do not warrant further investigation.
This paper is a departure from a 2012 paper by doctors at Tufts, which concluded that myocardial crypts were associated with HCM, and that they were often found in relatives of HCM patients found to be gene positive for HCM, but lacking the hallmark thickening of the ventricle.
Here is an example of what the crypts look like on MRI.
If you are looking for a good survey of current practices in the treatment of HCM, a recent article published in the journal Structural Heart by Dr. Ahmad Masri and the team at Oregon Health and Sciences University (OHSU) provides an informative overview of thirty controversies and considerations in the treatment of HCM. This article explains in some detail how the doctors at this HCM Center approach these situations.
Continue reading “HCM Treatment: The View from OHSU”