April 18, 2025
A new treatment option may be possible for patients with microvascular disease and debilitating chest pain. A Mayo Clinic study suggests that implanting an hourglass-shaped stent could improve blood flow, ease angina and enhance quality of life. The findings were published in JACC: Cardiovascular Interventions.
"A major highlight from the study is that a coronary sinus mesh implant may be a potential therapy for individuals with angina and nonobstructive coronary disease with microvascular dysfunction," says Amir Lerman, M.D., a cardiologist at Mayo Clinic in Rochester, Minnesota, and the senior author of the study.
A common cause of angina with no obstructive coronary artery disease (ANOCA) is coronary microvascular dysfunction (CMD). Effective treatment options are limited.
Forefront of research
This research is significant to the field and to patients. "Close to 40% of the patients undergoing clinically indicated coronary angiography are found to have nonobstructive coronary disease. Many of them have abnormality in the microvascular function. There's been no gold standard or guidelines therapy for these individuals," says Dr. Lerman. "This study provides for the first time information regarding device and procedure-oriented therapy for individuals with underlying coronary microvascular dysfunction."
Improving blood flow using an hourglass-shaped stent is cutting edge. "Using the coronary sinus mesh implant to treat nonrevascularized patients is part of the clinical practice in Europe and in Israel. However, the indication for the improvement of microvascular function is currently not a clinical practice and is being studied in several randomized studies in the United States and in Europe," says Dr. Lerman.
Why shape matters
The study addresses an unmet need since patients are experiencing recurring angina even with current medical therapies.
This study looked at the safety and efficacy of using an hourglass-shaped stent for treatment of angina in patients with CMD. The hourglass-shaped stent design creates a permanent and controlled narrowing of the coronary sinus to improve perfusion in ischemic myocardium.
The hourglass-shaped stent narrows in the middle — unlike the tube-shaped stents used to open clogged arteries. It redistributes blood flow more fully through the heart's small vessels that are not working at capacity.
Rather than address the symptoms, implanting an hourglass-shaped stent can target the cause of the angina — the reduction in blood flow affecting the heart muscle.
Study findings
The single-center, open-label, single-arm study was a phase 2 clinical trial that enrolled 30 patients with ANOCA despite medical therapy. The mean age was 54.8 ± 11.0 years, and 67% were women. CMD is more common in women.
Reduced blood flow to the heart can be debilitating. The patients with heart-related microvascular dysfunction in the study could not control their chronic angina, which limited their daily activities.
The mesh stent was successfully implanted in 30 patients, and 76% saw improvement in day-to-day life. Invasive coronary microvascular function testing was performed prior to implantation and again at 120 days postimplantation.
Coronary flow reserve (CFR) increased significantly in patients with low baseline CFR (endothelium-independent CMD), from 2.1 (1.95-2.30) to 2.7 (2.45-2.95) (n=19; P=0.0011).
Patients with abnormal coronary blood flow (CBF) response to acetylcholine at baseline (endothelium-dependent CMD) had an increase in CBF response to acetylcholine: -11.0% (-20.15% to 5.85%) to 11.5% (-4.82% to 39.29%) (n=11; P=0.042).
Mayo Clinic Cardiovascular Medicine researchers found that implanting this device can help improve angina symptoms, quality of life and coronary flow reserve in patients with microvascular angina dysfunction.
Looking ahead
More research is needed to understand long-term effects. "This study presents a new potential novel therapy for patients with angina and microvascular disease," says Dr. Lerman. "The next step should be addressing the use of the coronary sinus in a randomized study for the improvement of microvascular function and angina in symptomatic patients with nonobstructive coronary disease."
For more information
Tryon D, et al. Coronary sinus reducer improves angina, quality of life, and coronary flow reserve in microvascular dysfunction. JACC: Cardiovascular Interventions. 2024;17:2893.
Refer a patient to Mayo Clinic.