The development of the first drug therapy to treat hypertrophic cardiomyopathy (HCM) has led to an explosion of interest in the condition. While surgical myectomy and catheter-based alcohol septal ablation have been used to manage patients with severe enlargement of the myocardium that can block the left ventricular outflow tract (LVOT), HCM has remained a largely underdiagnosed and undertreated until now.
Ted Abraham, MD, co-director of the Hypertrophic Cardiomyopathy (HCM) Center of Excellence and director of the adult cardiac echocardiography laboratory at the University of California San Francisco, spoke with Cardiovascular Business to explain why HCM has come into the limelight at cardiology conferences, most notably the American Society of Echocardiography (ASE) 2023 annual meeting in June.
"HCM was a disease first described close to 80 years ago, and there has never been any specific therapy for HCM until about three years ago with the development of a drug called mavacamten, which gained FDA approval last year," Abraham said. "It is the first time there has been a disease-specific drug that has been extremely effective."
Many hospitals have set up mavacamten clinics and added additional training to detect and analyze HCM for their imagers.
He said cardiac ultrasound is the primary diagnostic imaging modality used to diagnosis HCM, risk stratifying patients and determining which ones may benefit from the new drug therapy. Echo HCM confirmation is also often the gatekeeper to more advanced CT and MRI imaging exams when more detailed anatomical and functional details are needed.
Due to the large role of echocardiography in HCM, Abraham said the ASE has decided to become more proactive and be at the forefront of expanding HCM education and research.
ASE leading effort to standardize and expand HCM screening, diagnosis and treatment
ASE President Stephen Little, MD, mentioned the society's efforts to address HCM during his address at the opening session at ASE 2023. He highlighted the society's role in bringing more attention of HCM, including the release of recommendations for multimodality imaging of HCM patients in 2022.
Abraham noted that ASE also hosted an HCM forum event the day after the ASE annual meeting this year that included experts from several cardiology societies. The forum was designed to bring together several key opinion leaders to discuss next steps and gaps that need to be addressed in HCM patient care now that there is growing interest in the disease. The key takeaways from the five-hour discussion in the forum were that more standardization is needed in the imaging, reporting language, reporting fields in report templates and how interventional and surgical procedures for HCM are performed.
Experts in the forum expressed the need to make sure patients who need treatment beyond pharmaceutical therapy are sent to HCM centers of excellence or higher volume HCM surgical and interventional centers. Speakers at the forum agreed the current low volume of these patients means most hospitals cannot become experts in HCM myectomy or alcohol septal ablation. This inexperience requires patients to be sent to higher volume centers that do have expertise with these patients and procedures. There also were calls for HCM patient registries so that data can be collected in a standardized format nationally. Forum participants said this data is needed to better understand what works and what does not in this patient population and to develop better risk stratification models. Several experts also complained at the forum that current clinical evidence cited in guidelines is based largely on single center studies with only small numbers of patients.
"ASE has been instrumental in bringing all these parties together to talk at the forum. This will serve as a launching pad for a future larger conference next year in New York City, where we will we will have a significantly larger audience that will talk more in-depth on this topic," Abraham explained. "The drug mavacamten is being used as a launchpad for this effort, but what we have recognized for a while is that echocardiography and multimodality imaging is used in almost every aspect of HCM treatment. This includes right from screening for the disease, diagnosing the disease, to every aspect of patient management,"
HCM remains an underdiagnosed heart disease
Abraham explained that HCM is believed to be the most common inherited genetic cardiac condition in the world. In the U.S., it is estimated there are between 700,000 to 900,000 patients at risk for HCM. The world-wide burden is estimated to be about 20 million patients. This is why HCM is important for people to pay attention to and understand what the clinical signs are on imaging.
"So it is a disease that is thought to be rare, but it really is not so rare," Abraham said.
He added that 90% of patients with an HCM diagnosis will generally live normal, healthy and full lives.
"You want to reassure patients who do not have high-risk features that they will do well. But you also want to identify those who will need an intervention," Abraham said.
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: dfornell@innovatehealthcare.com