IMPORTANCE Loading doses of atorvastatin did not show reduction on clinical outcomes in the overall population of patients with acute coronary syndrome (ACS) enrolled in the Statins Evaluation in Coronary Procedures and Revascularization (SECURE-PCI) trial, but a potential benefit was identified in patients who subsequently underwent percutaneous coronary intervention (PCI). OBJECTIVES To determine whether periprocedural loading doses of atorvastatin are associated with decreased 30-day major adverse cardiovascular events (MACE) in patients with ACS undergoing PCI according to type of ACS and timing of atorvastatin administration before PCI. DESIGN, SETTING, AND PARTICIPANTS Secondary analysis of a multicenter, double-blind, placebo-controlled, randomized clinical trial conducted at 53 sites that enrolled 4191 patients with ACS intended to be treated with PCI between April 18, 2012, and October 06, 2017. INTERVENTIONS Patients were randomized to 2 loading doses of 80 mg of atorvastatin or matching placebo before and 24 hours after a planned PCI. By protocol, all patients (regardless of treatment group) received 40 mg of atorvastatin for 30 days starting 24 hours after the second dose of study medication. MAIN OUTCOMES AND MEASURES The primary outcome was MACE through 30 days, composed by all-cause mortality, myocardial infarction, stroke, and unplanned coronary revascularization. Cox regression models adjusting for key baseline characteristics were used to assess the association between atorvastatin and MACE in patients undergoing PCI. RESULTS Fromtheoveralltrialpopulation,2710(64.7%)underwentPCI(650women[24.0%];mean [SD] age, 62 [11.3] years). Loading atorvastatin was associated with reduced MACE at 30 days by 28% in the PCI group (adjusted hazard ratio [HR], 0.72; 95% CI 0.54-0.97; P = .03). Loading dose of atorvastatinwasadministeredlessthan12hoursbeforePCIin2548patients(95.3%)(45.1% < 2hours and 54.3% between 2 and 12 hours). There was no significant interaction between treatment effect and timing of study drug administration. The treatment effect of loading atorvastatin was more pronounced in patients with ST-segment elevation myocardial infarction than in patients with non-ST-segment elevation ACS (adjusted HR, 0.59; 95% CI, 0.38-0.92; P = .02; HR, 0.85; 95% CI, 0.58-1.27; P = .43, respectively). CONCLUSIONS AND RELEVANCE In patients with ACS undergoing PCI, periprocedural loading doses of atorvastatin appeared to reduce the rate of MACE at 30 days, primarily in patients with ST-segment elevation myocardial infarction. This beneficial effect seemed to be preserved and consistent, regardless of timing of atorvastatin administration, including within 2 hours before PCI. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01448642