Just over a decade ago, an interventional cardiology team led by Richard Smalling, M.D., Ph.D., professor of internal medicine, knew it had a problem as results of a dye test lit up the monitor.
A patient with a thickening heart muscle was down to her last hope for easing the shortness of breath and debilitating fatigue that came with the rare condition. She wasn’t a candidate for open heart surgery, and the other option — alcohol septal ablation (ASA) — had just been ruled out because of the anatomy of her heart.
In Smalling’s words, “She was ready to give up the ghost.”
But Smalling, the Jay Brent Sterling Professor of Cardiovascular Medicine and James D. Woods Distinguished Chair of Cardiovascular Medicine, decided to try something different — the deployment of coils into blood vessels feeding the thickened muscle that impeded blood flow through the heart.
The positive safety and efficacy results of a 10-year clinical trial launched after that first procedure were recently published in the journal Catheterizations and Cardiovascular Interventions. The procedures took place at Memorial Hermann Heart & Vascular Institute-Texas Medical Center (HVI).
Called septal coil embolization, the procedure is for a condition called hypertrophic obstructive cardiomyopathy (HOCM), which occurs when the heart muscle thickens and impedes the flow of blood out of the heart’s left ventricle. About 1 in 500 adults have it.
The classic symptoms of hypertrophic obstructive cardiomyopathy include dizziness, shortness of breath, and fatigue. This condition is usually hereditary but can develop over time due to high blood pressure or aging, according to the American Heart Association.
Medications can improve the blood flow of HOCM patients about half the time. When drugs do not work, doctors will sometimes remove a tiny part of the heart surgically through an operation called a septal myectomy. The standard non-surgical option, called alcohol septal ablation (ASA), is to destroy the thickened muscle via blood vessels feeding it using ethanol.
The problem with ASA is that the ethanol solution can travel into surrounding vessels and tissue. What Smalling’s team saw on the monitor was that the dye injected into the vessels in the problem area shot up into the entire heart muscle, which meant the ethanol would kill the patient.
Coils, which remain stationary, seemed to be the right option for these patients. Coil embolization is performed by inserting a catheter in a patient’s femoral artery near the groin and guiding it to the narrowed area with the aid of echocardiography and X-ray imaging. The coils, which are attached to a delivery wire, are then used to plug the blood vessels feeding the thickened muscle, which will then partially die and thin over time.
To gauge the safety and effectiveness of coil embolization, Smalling’s team studied 24 patients who had the procedure between 2005 and 2015. Twenty-two of the patients experienced significant improvement.
Smalling said the benefits of coil embolization over ASA include fewer complications, shorter hospital stay, and less pain during the procedure. Only about 5 percent of coil embolization patients required a pacemaker in comparison to up to 30 percent with ASA.
Smalling, the study’s senior author and chief of interventional cardiology at McGovern Medical School and HVI, said the next step will be a clinical trial comparing coil embolization to ASA.
Meanwhile, patients like West Texas rancher Alvin Dunn, 68, are still benefiting from the procedure. Dunn underwent a coil embolization performed by Smalling and the HVI team on Nov. 22.
“I’m back to feeding my cattle,” said Dunn, who lives in Ballinger, a city of about 4,000 people that is billed as “The Greatest Little Town in Texas.” “I can also enjoy my grandchildren. Being able to keep up with them is no easy task.”
UTHealth co-authors of the study include Israel Guerrero, M.D.; Abhijeet Dhoble, M.D., M.P.H.; Mark Fasulo, M.D.; Shehzad Sami, M.D.; Sangbum Choi, Ph.D.; Prakash Balan, M.D., J.D.; and Salman Arain, M.D. Ali E. Denktas, M.D., of Baylor College of Medicine, was also a co-author.