Association between periprocedural change in serum renalase and microvascular obstruction in patients with STEMI after primary percutaneous coronary intervention: protocol for the ReMVOS prospective cohort study.

introductionMicrovascular obstruction (MVO) is a common complication following primary percutaneous coronary intervention (PPCI) for ST-segment elevation myocardial infarction (STEMI) and is strongly associated with adverse clinical outcomes. MVO is a dynamic, multifactorial process shaped by factors spanning the myocardial infarction-reperfusion continuum and by PPCI-related microcirculatory injury, which leaves current early risk stratification-often a static snapshot-with limited power to anticipate its evolution. Renalase, a cardioprotective enzyme, exhibits a post-reperfusion surge that parallels MVO development; periprocedural renalase release may likewise be driven by overlapping mechanisms along the ischaemia-reperfusion pathway. This hypothesis-generating observation supports evaluating the delta-Renalase (periprocedural change in serum renalase) as a candidate association-based biomarker. Accordingly, this study aims to assess whether delta-Renalase is independently associated with MVO in patients with STEMI after PPCI and to evaluate its incremental predictive value, without causal inference. METHODS AND ANALYSIS: The Renalase and MicroVascular Obstruction Study (ReMVOS) is a prospective, single-centre, observational cohort study conducted at a nationally accredited chest pain centre in China. We will enrol 266 patients with consecutive STEMI with symptom onset within 12 hours who undergo PPCI. The exposure variable is delta-Renalase, calculated as the increase in serum renalase levels at 24 hours post-PPCI relative to the preprocedural baseline. The primary outcome is the presence of MVO, assessed by cardiovascular magnetic resonance (CMR) performed 2-5 days post-PPCI. Secondary outcomes include infarct size and peak global longitudinal strain quantified by CMR, major adverse cardiovascular events within 90 days and peak oxygen pulse from cardiopulmonary exercise testing (CPET) at the 90-day visit. The independent association and predictive value of delta-Renalase will be evaluated using a prespecified multivariable logistic regression model. ETHICS AND DISSEMINATION: This protocol has been approved by the Ethics Committee of the Third Xiangya Hospital of Central South University (approval No. K24655). All patients will provide written informed consent prior to enrolment. The findings of this study will be disseminated through publications in peer-reviewed international medical journals and presentations at relevant academic conferences. TRIAL REGISTRATION NUMBER: NCT06669520.