Ticagrelor increases adenosine plasma concentration in acute coronary syndrome patients (ACS) by inhibiting adenosine uptake by red blood cells. Besides, ticagrelor treatment might be more effective than clopidogrel in reducing microvascular injury in ST-elevation myocardial infarction (STEMI) patients. However, the effects of ticagrelor on coronary physiology parameters in ACS patients with multivessel disease (MVD) remain uncertain.

We designed a prospective study to assess the effects of ticagrelor treatment on microvascular resistance in ASC patients with MVD.

Ten consecutive non-STE-ASC patients with no prior ticagrelor treatment and MVD, defined as the presence of at least one significant (>50%) lesion in a non-infarct related artery, underwent intracoronary physiology parameters assessment immediately after primary percutaneous coronary intervention (PCI) of the culprit lesion. A second series of measurements was performed after 72hours of ticagrelor treatment. The primary endpoint was the index of microvascular resistance (IMR) in a non-infarct related artery. The secondary endpoints were IMR in the culprit artery and the fractional flow reserve (FFR) both in a non-infarct related artery and in the culprit artery.

IMR measured in a non-infarct related artery was significantly lower after 72h of ticagrelor treatment (19.2±11.2 vs. 14.2±7.4, P=0.02) whereas IMR in the culprit artery was not significantly different from baseline (13.1±4.1 vs. 18.7±11.4, P=0.13). FFR measurements were not significantly different after ticagrelor treatment both in the non-infarct related artery and in the culprit artery after primary PCI (85±0.15 vs. 0.86±0.17, P=0.80 and 0.98±0.04 vs. 0.98±0.04, P=0.56 respectively) (Table 1).

Ticagrelor decreases microvascular resistance in non-infarct related artery in ASC patients with MVD.