HCM drug advances have been a breakthrough—but more invasive treatments are still vital
New drug therapies for hypertrophic cardiomyopathy (HCM) are expanding treatment options for patients and reducing the amount of invasive procedures being performed on a day-to-day basis. This is raising concerns about whether sufficient expertise will remain for patients who still end up requiring surgical myectomy or alcohol septal ablation.
Srihari S. Naidu, MD, director of cath labs and HCM at Westchester Medical Center and immediate-past president of the Society for Cardiovascular Angiography and Interventions (SCAI), spoke with Cardiovascular Business about this very topic for a new video interview. He noted how much cardiac myosin inhibitors have changed the treatment landscape for obstructive HCM since their introduction just a few years ago.
Mavacamten, a cardiac myosin inhibitor, reduces excessive myocardial contractility by decreasing myosin cross-bridging. Naidu said roughly 85% to 90% of the approximately 3,000 HCM patients in his practice can tolerate the drug, although its required monitoring for potential drug interactions. He added that patients also face logistical challenges due to distances for monitoring to to obtain the drugs.
A newer cardiac myosin inhibitor, aficamten, offers a shorter half-life and requires fewer required echocardiographic assessments, potentially making it an attractive alternative for some patients. Naidu said the shorter half-life allows physicians to adjust therapy more quickly if a patient's ejection fraction declines, while also potentially creating greater risk if patients abruptly miss doses.
Another advantage of aficamten is that there are potentially fewer drug-drug interactions, which can be an especially big risk with oral contraceptive pills.
"There was some potential interaction with mavacamten, but not with aficamten, so that opens up a segment of the population of young women in reproductive age that may want to be on these medications first," Naidu said.
Rather than one drug replacing another, Naidu expects physicians will select between the therapies based on individual patient characteristics.
HCM drug therapy is largely replacing invasive therapies
The growing use of medications, however, has had a significant effect on invasive HCM treatment. Naidu estimates that alcohol septal ablation volumes have fallen about 50% overall, with an initial decline of approximately 70% before procedure volumes began to recover somewhat.
The concern, he said, is that declining procedural volumes could erode the expertise needed to treat patients who cannot tolerate or do not have access to drug therapy.
"I'm a little concerned that that expertise may not be there," Naidu explained. "More so for myectomy than ablation, because my impression is myectomy has taken a bigger hit because most people would rather not have surgery. So they will try the medications uniformly. Whereas with alcohol ablation, I think it tends to be older population of patients who have some logistical barriers to coming in for routine echoes, may have drug-drug interactions, may have polypharmacy, or may have other reasons to not be on the medication."
For some older patients, definitive elimination of the obstruction through a procedure may also simplify long-term management, particularly when other medical conditions or unexpected surgeries arise.
Naidu said procedural expertise can disappear when physicians perform only a handful of cases annually, retire or relocate. He emphasized that medications, myectomy and alcohol ablation should be viewed as complementary rather than competing approaches.
“We need all of these tools at our disposal,” Naidu said, adding that the field needs to ensure invasive therapies remain available alongside drug treatment.
The growth of drug therapy also creates concerns about comprehensive HCM care. Naidu said patients receiving myosin inhibitors still need assessments for other important aspects of HCM, including genetic screening, family screening, annual follow-up and sudden cardiac arrest risk. He suggested that patients receiving medications in the community could be connected with specialized HCM centers virtually and evaluated at least annually to ensure those risks are not overlooked.
At the same time, the expansion of drug treatment is helping identify patients who previously went undiagnosed. Naidu said HCM was historically under recognized, in part because clinicians were less likely to look for a condition for which few treatment options existed.
Greater awareness, wider use of cardiac MRI and recognition of myocardial scar are now helping clinicians establish HCM diagnoses, potentially benefiting patients and their families through earlier evaluation and screening.
The challenge for the field, Naidu said, will be maintaining the infrastructure and expertise for invasive treatment while taking advantage of the new medical therapies that have made HCM more treatable.
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: [email protected]