Relationship between coronary diastolic pressure indexes during the wave-free period and a novel pressure-derived index: Diastolic pressure ratio at the optimal point.

OBJECTIVES

We aimed to determine the diastolic pressure ratio at the optimal point (DROP) using a simple measurement algorithm and to compare DROP with distal coronary-to-aortic pressure ratios during the wave-free period (PR ) and at the mid-diastolic point (PR ).

METHODS

Distal coronary and aortic pressures were measured from color pressure images of 440 beats in 48 patients with coronary stenoses. The DROP measurement point was 67% for one beat between the two rising points on the aortic pressure curve according to the distribution of the wave-free period and the mid-diastolic point.

RESULTS

DROP correlated closely with PR (r = 0.993, P < 0.0001) and PR (r = 0.997, P < 0.0001). The diagnostic efficiency was excellent (area under the receiver-operating characteristic curve, 0.997) for both PR  ≤ 0.89 (specificity, 0.99; sensitivity, 0.96) and PR  ≤ 0.89 (specificity, 0.95; sensitivity, 1.00).

CONCLUSIONS

A simple pressure-derived physiological marker of coronary stenosis, DROP, might represent other diastolic pressure indexes with a numerical equivalency to the instantaneous wave-free ratio. DROP can be measured automatically assuming that the rising points on the aortic pressure curve are detectable. However, further large-scale clinical investigations are needed to determine whether DROP could contribute to the further generalization of physiology-guided percutaneous coronary intervention.