Impact of preceding acetylcholine provocation testing on following coronary physiological assessment during an interventional diagnostic procedure.

BACKGROUND

Intracoronary acetylcholine (ACh) provocation test and coronary physiological assessment are useful interventional diagnostic procedures for evaluating ischemia with no obstructive coronary arteries (INOCA). However, the appropriate sequential order of the diagnostic procedures has been a matter of debate. We investigated the impact of preceding ACh provocation on following coronary physiological assessment.

METHODS

Patients suspected of INOCA underwent invasive coronary physiological assessment using thermodilution method and were divided into two groups according to the implementation of ACh provocation test. The ACh group was further divided into the positive and negative ACh groups. In the ACh group, intracoronary ACh provocation was performed before the invasive coronary physiological assessment. The main interest of this study was to compare coronary physiological indices among the no ACh, negative ACh, and positive ACh groups.

RESULTS

Of 120 patients, the no ACh, and negative and positive ACh groups included 46 (38.3 %), 36 (30.0 %), and 38 (31.7 %), respectively. Fractional flow reserve was lower in the no ACh group than in the ACh group. Resting mean transit time was significantly longer in the positive ACh group, followed by the no ACh and negative ACh groups (1.22 ± 0.55 vs. 1.00 ± 0.46 vs. 0.74 ± 0.36 s, p < 0.001). Index of microcirculatory resistance and coronary flow reserve did not differ significantly among the three groups.

CONCLUSIONS

Preceding ACh provocation influenced following physiological assessment, particularly when ACh test was positive. Further studies are warranted to determine which interventional diagnostic procedure, ACh provocation or physiological assessment, should be preceded in the invasive evaluation of INOCA.