Clinical Significance of Microvascular Obstruction Following Primary Percutaneous Coronary Intervention

Objective: To evaluate the clinical significance of Microvascular obstruction following primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) and to assess its impact on myocardial recovery and long-term outcomes. Methodology: This retrospective study was conducted at Department of Cardiology, Hayatabad Medical Complex, Peshawar, from January 2018 to December 2018. A total of 250 STEMI patients undergoing primary PCI were enrolled. Data on demographics, clinical presentation, angiographic characteristics, and procedural details were collected. Microvascular obstruction (MVO) was assessed using cardiac magnetic resonance imaging (CMR) 48 hours post-PCI. Statistical analysis included chi-square tests, t-tests, and logistic regression models. Results: Among 250 patients, 150 (60%) were males and 100 (40%) were females, with a median age of 58 years (range 25-85). MVO was detected in 35% of patients. Myocardial Blush Grade (MBG) was Grade 3 in 30%, Grade 2 in 50%, and Grade 1 in 20% of patients. Infarct size ≤30% was seen in 50% of patients, 30-50% in 40%, and >50% in 10%. Adjunctive therapies significantly reduced MVO incidence (p=0.02). Logistic regression identified age ≥60 (OR=2.1, p=0.015), infarct size >30% (OR=3.2, p=0.008), and MBG 1 (OR=3.4, p=0.003) as significant predictors of MVO. Conclusion: MVO significantly impacts myocardial recovery post-PCI, increasing infarct size and reducing left ventricular function. Early detection and adjunctive therapies improve outcome. Future research should explore long-term prognostic implications. Keywords: Microvascular obstruction, primary PCI, STEMI, myocardial blush grade, cardiac MRI.