OBJECTIVES: The Multi-center Prospective Study to Evaluate Outcomes of Moderate to Severely Calcified Coronary Lesions (MACE-Trial) was designed to provide further insight on the impact of calcification on procedural and long-term percutaneous coronary intervention outcomes. BACKGROUND: Prior studies evaluating the impact of lesion calcification on percutaneous coronary intervention outcomes are limited by: retrospective nature, pooled data from multiple studies, or lack of specificity around calcification with only operator assessment and without core lab evaluation. METHODS: The MACE-Trial was a prospective, multicenter, observational clinical study that enrolled 350 subjects at 33 sites from September 2013 to September 2015. Core lab assessed subject stratification by lesion calcification (none/mild [N = 133], moderate [N = 99], and severe [N = 114]). Endpoints were lesion success, procedural success, and 1-year major adverse cardiac events (MACEs). RESULTS: Presence of severe calcification had significant impact on lesion success ([83.3%] versus none/mild calcification [94.7%, P = 0.006]) and procedural success ([86.8%] versus moderate [95.0%, P = 0.028], and none/mild [97.7%, P = 0.001]). 1-year MACE rates were associated with presence of calcification in subjects with none/mild (4.7%), moderate (8.7%), and severe (24.4%) (P < 0.001) calcification; however, no difference was noted between none/mild and moderate (P = 0.237). The risk adjusted multivariable model identified severe calcification and decreasing eGFR as predictors of 30-day and 1-year MACE. CONCLUSIONS: In this prospective study, patients with severe calcification had significantly worse outcomes compared to those without; however, unlike previous retrospective studies, moderate calcium resulted in similar outcomes as none/mild calcium. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov/ct2/show/NCT01930214. Unique Identifier: NCT01930214.