The Impact of Coronary Sinus Narrowing On Diastolic Function in Patients With Myocardial Ischemia And Refractory Angina

Background: Coronary Sinus (CS) Reducer implantation is an emerging therapy for patients suffering from refractory angina pectoris. The Reducer establishes a narrowing in the CS with pressure gradient across it thus improves perfusion to the ischemic subendocardium and relieves angina. It was speculated that increased CS pressure might cause interstitial myocardial edema and diastolic dysfunction, nevertheless, the impact of CS narrowing on diastolic function has not been previously evaluated.

Methods: Prospective assessment of diastolic function was performed at baseline and 6 months following CS Reducer implantation. Diastolic function assessment included left atrial volume, early transmitral filling peak velocity (E wave), E wave deceleration time (DT), transmitral atrial wave velocity (A wave), and early diastolic velocity of the septal (e’ septal) and lateral (e’ lateral) aspects of the mitral annulus.

Results: Overall, 24 patients (69.3±10.9 years, 92% males) were included. A wave velocity, E/A ratio, E wave DT and left atrial volume did not significantly change following Reducer implantation (p>0.1 for all comparisons). A non-significant decrease in E wave velocity (80.5±22.3 cm/s vs. 75.7±17.5 cm/s, p=0.19) and increase in e’ septal and lateral (5.28±1.54 cm/s vs. 5.30±1.71cm/s, and 8.26±1.85 cm/s vs, 8.46±2.07 cm/s, p>0.1 for both) led to a non-significant decrease in E/e’ average ratio (12.6±5.7 vs. 11.4±3.3, p=0.24). However, diastolic dysfunction class significantly decreased from 1.5±0.66 to 1.17±0.76 (p=0.008).

Conclusion: CS narrowing in patients with myocardial ischemia and refractory angina does not adversely affect diastolic function and may actually improve it. Larger studies are required to further establish this finding.