Recent advancements in surgical techniques and intraoperative imaging methods by doctors at NYU Langone’s Hypertrophic Cardiomyopathy Program can enhance outcomes for patients with this genetic heart condition.

Modified Myectomy Allows More Patients to Avoid Mitral Valve Replacement

Surgical director Daniel G. Swistel, MD, associate professor of cardiothoracic surgery, originally pioneered a significant surgical modification to traditional myectomy, performed on patients with obstructive hypertrophic cardiomyopathy (HCM) for whom pharmacologic therapy is ineffective.

The horizontal plication procedure improves blood flow by shortening the mitral valve, which often protrudes into the left ventricular chamber in patients with HCM. As echocardiography has more precisely shown the abnormalities of the mitral valve, Dr. Swistel has altered his approach by excising the residual (extra) portion of the mitral valve, termed residual leaflet excision (ReLex). This can be especially useful in patients who preoperatively are shown to have only mild septal thickening.

“These patients used to require mitral valve replacement,” explains Mark V. Sherrid, MD, professor of medicine, director of the Hypertrophic Cardiomyopathy Program, and a nationally recognized cardiologist who was instrumental in establishing the utility of disopyramide therapy for obstructive HCM. “With these techniques, 95 percent of them can keep their own valve instead of receiving an artificial or bioprosthetic implant.”

Affecting about 1 in 500 people, HCM is the most common inherited heart condition, and the leading cause of sudden death among people under 30 years of age. NYU Langone is one of just a handful of institutions to offer comprehensive management of this disorder. With more than 2,500 patients, the Hypertrophic Cardiomyopathy Program is among the largest such programs in the world, with a record of innovation spanning 3 decades.

Dr. Swistel and Dr. Sherrid have published two papers related to their work in this field. The first, “The Surgical Management of Obstructive Hypertrophic Cardiomyopathy: The RPR Procedure—Resection, Plication, Release,” appeared in the Annals of Cardiothoracic Surgery and was accompanied by a 23-minute online instructional video.

The second paper, whose first author is Robert G. Nampiaparampil, MD, assistant professor of anesthesiology, perioperative care, and pain medicine, was “Intraoperative Two- and Three-Dimensional Transesophageal Echocardiography in Combined Myectomy-Mitral Operations for Hypertrophic Cardiomyopathy.” The article reviewed the innovative techniques used at NYU Langone for intraoperative two- and three-dimensional transesophageal echocardiography in combined myectomy-mitral operations for HCM and was published in the Journal of the American Society of Echocardiography.

The two papers underscore NYU Langone’s eminence and leadership in this field.

Surgical Advances in Intraoperative Imaging of Septal Thickness

One major challenge in the surgical treatment of HCM is that there is no way to monitor the depth of septal myectomy during the on-pump period, since transesophageal echocardiography is impossible when the heart is empty of blood. An experimental technique recently developed and named by NYU Langone’s HCM team, known as on-pump intraoperative echocardiography (OPIE), offers a solution.

In this method, a tiny probe, originally designed for pituitary surgery, is inserted through the aortic valve while the right heart chamber is filled with fluid, creating an interface that the echocardiogram can differentiate.

An Institutional Review Board (IRB)-approved trial of OPIE involving 10 patients was completed last year, and an abstract has been submitted for presentation at the 2019 annual meeting of the American College of Cardiology.

“Our initial findings suggest that this device can improve the efficacy and safety of myectomy procedures,” says Dr. Swistel, who led the study. “We think it will revolutionize the management of patients with only modest hypertrophy of the septum, for whom the line between ‘too little myectomy’ and ‘too much myectomy’ can be difficult to assess with current methods.”