Association between ticagrelor loading timing within the primary PCI workflow and ST-segment resolution in STEMI: a single-center real-world cohort study

We examined whether the timing of ticagrelor loading relative to culprit-lesion wire crossing within the primary PCI workflow was associated with ST-segment resolution (STR) after STEMI. The loading-to-wire-crossing interval was treated as a workflow-related timing measure rather than a direct pharmacodynamic exposure. This single-center retrospective cohort included 600 of 680 consecutive patients evaluated for STEMI and initially planned for emergency primary PCI between January 2023 and December 2024. All received aspirin 300 mg and ticagrelor 180 mg. The interval was analyzed primarily as a continuous variable per 10-min increase, with STR ≥ 70% as the primary outcome. Modified Poisson regression with robust standard errors was the primary framework; logistic regression was secondary. Key sensitivity analyses additionally adjusted for ticagrelor administration location or restricted the analysis to emergency-department loading. The 30-min dichotomization and opioid interaction were exploratory. Among 600 patients, 438 (73.0%) achieved STR ≥ 70%. In the overall workflow-associated model, each 10-min increase in the recorded interval corresponded to an adjusted RR of 1.02 for STR ≥ 70% (95% CI 1.01–1.04, P < 0.001). After additional adjustment for administration location, the point estimate remained similar but became less precise and was no longer statistically significant (adjusted RR 1.02, 95% CI 1.00–1.05, P = 0.067). Among 339 patients loaded in the emergency department, the continuous association was not significant (adjusted RR 1.02, 95% CI 0.96–1.07, P = 0.558). In the exploratory emergency-department overlap-weighted ≥ 30 versus < 30-min comparison, the weighted RR was 1.10 (95% CI 0.97–1.25, P = 0.155). Restricted cubic spline analysis showed no evidence of nonlinearity ( P = 0.770). The overall association between the loading-to-wire-crossing interval and STR ≥ 70% could not be separated reliably from ticagrelor administration setting and was not supported by the setting-restricted analyses. The interval should therefore be interpreted as a workflow-related measure and not as a rationale for delaying mechanical reperfusion.