This study looked at the role of fractional myocardial mass (vessel-specific myocardial mass) in the assessment of stenosis physiological severity.

Researchers used CT angiography to study this new concept of myocardial mass subtended by a specific vessel, which could reduce anatomical-physiological mismatch.

The study included 463 patients with 724 lesions evaluated by multislice coronary computed tomography angiography and invasive coronary angiography with fractional flow reserve measurement (FFR).

Fractional myocardial mass was assessed based on arterial tree length and myocardial mass by CT.

FFR <0.80 was considered a functionally significant lesion and it was found in 39% of observed vessels. Fractional myocardial mass decreased consistently according to vessel caliber, which is obvious.

FFR <0.80 increased in direct proportion to fractional myocardial mass and inversely to angiographic minimal luminal diameter (p < 0.001).

Fractional myocardial mass and minimal luminal diameter showed good correlation with FFR (r=0.61) and resulted superior to stenosis diameter to predict FFR <0.80.

Optimal cutoff value for fractional myocardial mass/minimal luminal diameter was 29 g/mm with 75% sensitivity,   77% specificity and 77% diagnostic accuracy.

This relation could add information to the classical stenosis diameter to predict FFR<0.80.

Conclusion

The relation fractional myocardial mass / minimal luminal diameter could help discriminate functional compromise of vessels more accurately than anatomical stenosis. The concept of fractional myocardial mass could explain the discrepancy between anatomy and physiology.

Original Title: Physiological Severity of Coronary Artery Stenosis Depends on the Amount of Myocardial Mass Subtended by the Coronary Artery.

Reference: Hyung Yoon Kim et al. JACC Cardiovasc Interv. 2016 Aug 8;9(15):1548-60.

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