Coronary Blood Flow Measurement in Conventional Coronary Angiograms by a New Method Based on Contrast Density Detection. A Physiological Insight

Abstract

Background

TIMI flow grade and corrected TIMI frame count (CTFC) are widely used methods to evaluate angiographic coronary blood flow. Measurement of coronary blood flow (CBF) on standard coronary angiography (CAG) has aroused great interest recently, trying to combine the CTFC concept with new methods for post-angioplasty and for cardiac syndrome X assessment. Additionally, coronary slow flow it is now considered a major criterion for microvascular angina.

Objective

Explore a new approach of quantitative angiographic measurement of CBF based on densitometric contrast detection in CAG off-line, using an accessible software to obtain a more precise and reliable CBF assessment.

Methods

Thirty patients were studied and divided in 2 groups, normal coronary blood flow (NF) and slow coronary blood flow (SF), according to CTFC definition. The DM was applied to the study sample to differentiate between NF and SF. Non-parametric statistics was used to assess differences between groups at p<0.05.

Results

The DM normal reference value obtained for coronary blood flow was 9 [5–10] frames. NF vs SF group were compared and expressed as median [interquartile range], for the left anterior descending: 10 [7-11] vs 21 [8-33];p= 0.016; circumflex: 9 [4-13] vs 14 [11-30]; p= 0.012 and right coronary artery: 5 [3-11] vs 13 [8-26]; p=0.009.

Conclusion

The DM showed the feasibility of measuring coronary blood flow with precision, consistency and reproducible in a standard coronary angiogram, showing the additional capability to differentiate between NF and SF in chest pain patients with normal coronary arteries. (Arq Bras Cardiol. 2020; 115(3):503-512)

Coronary Artery Disease; Cardiac syndrome X; Blood Circulation/physiopathology; Stable angina; Coronary angiography/methods; Microvascular angina