Comparative Visual Analysis of Coronary Slow Flow and Myocardial Blush Grade in Relation to Invasive Testing for...

Area of Science:

• Cardiology
• Vascular Biology
• Diagnostic Imaging

Background:

• Coronary slow flow (CSF) and abnormal myocardial blush grade (MBG) are linked to coronary microvascular dysfunction (CMD) and adverse outcomes.
• The diagnostic accuracy of these angiographic markers compared to invasive methods for CMD is not well-established.

Purpose of the Study:

• To evaluate the correlation between angiographic assessments of CSF and MBG and gold-standard invasive coronary functional testing (CFT) for CMD diagnosis.

Main Methods:

• The Coronary Microvascular Disease Registry identified patients with angina and non-obstructive coronary arteries (ANOCA) undergoing invasive CFT.
• CMD was defined by invasive bolus thermodilution (coronary flow reserve < 2.5 and index of microcirculatory resistance > 25).
• CSF and MBG were assessed angiographically and compared between CMD-positive and negative groups.

Main Results:

• Of 304 patients, 26.6% had CMD. No significant differences were observed in the rates of abnormal CSF (8.6% vs. 4.9%) or slow Thrombolysis in Myocardial Infarction frame count (14.8% vs. 15.7%) between CMD-positive and negative groups.
• Similarly, the rates of abnormal MBG were comparable (1.3% vs. 3.1%) across groups.
• Patient demographics showed CMD-positive individuals were slightly older and had lower BMIs.

Conclusions:

• Angiographic CSF and MBG are not reliable indicators of CMD in ANOCA patients.
• Invasive CFT should be considered for definitive CMD diagnosis when clinically suspected.