Coronary Sinus Narrowing for the Treatment of Patients With Angina and Evidence of Microvascular Dysfunction: A Prospective Single-Arm Study.
Maayan Konigstein, Itamar Loewenstein, Ophir Freund et al.
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In 30 seconds
This prospective, single-arm study evaluated coronary sinus Reducer implantation in 40 patients with refractory angina, nonobstructive coronary artery disease, and evidence of coronary microvascular dysfunction. At 4 months, median index of microcirculatory resistance fell from 35 to 17 (P < 0.001), while median coronary flow reserve rose from 1.6 to 2.8 (P < 0.001). Angina class, 6-minute walk distance, and all five Seattle Angina Questionnaire domains also improved. The findings suggest potential benefit across measured microvascular, symptom, functional, and quality-of-life outcomes, but the uncontrolled design does not establish that implantation caused these changes.
Key findings
- Median index of microcirculatory resistance decreased from 35 [IQR, 25-43] to 17 [IQR, 10-32]; P < 0.001.
- Median coronary flow reserve increased from 1.6 [IQR, 1.3-2.0] to 2.8 [IQR, 1.9-3.3]; P < 0.001.
- Median 6-minute walk distance increased from 300 [IQR, 231-400] to 383 [IQR, 278-452] m; P < 0.001.
- Canadian Cardiovascular Society class improved from a median of III to II, and all five Seattle Angina Questionnaire domains improved (P < 0.05 for all).
Why it matters
Angina associated with coronary microvascular dysfunction can be difficult to manage. These findings indicate that coronary sinus Reducer implantation was followed by improvements not only in invasive measures of microvascular function but also in symptoms, walking capacity, and reported quality of life. The results provide a rationale for further evaluation of this approach in patients with refractory angina and nonobstructive coronary disease.
What to keep in mind
The study was single-arm and assessed outcomes at 4 months; without a comparator, observed improvements cannot be attributed definitively to implantation.