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 (PRWFP ) and at the mid-diastolic point (PRMD ). 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 PRWFP (r = 0.993, P < 0.0001) and PRMD (r = 0.997, P < 0.0001). The diagnostic efficiency was excellent (area under the receiver-operating characteristic curve, 0.997) for both PRWFP  ≤ 0.89 (specificity, 0.99; sensitivity, 0.96) and PRMD  ≤ 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.