Kounis Syndrome: A Systematic Review and Meta-analysis

Kounis syndrome (KS), an allergic acute coronary syndrome, remains incompletely characterized because available evidence is largely limited to case reports and small case series. We conducted a Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review and meta-analysis with pooled patient-level data to quantitatively synthesize demographic patterns, clinical features, management strategies, and outcomes across published KS cases. A PubMed search identified 892 records, of which 3 studies met eligibility criteria, yielding 71 extractable cases. Study-level proportions were pooled using random-effects models with assessment of between-study heterogeneity. Age distribution varied by trigger, with contrast-related cases occurring at older ages, cephalosporin-associated cases at intermediate ages, and nonsteroidal anti-inflammatory drug-related cases at younger ages. Male predominance was consistent, with pooled estimates approximating 75%. ST-segment elevation was common, and angiographic abnormalities were present in 42%. Subtype distribution demonstrated substantial heterogeneity, particularly for Type I KS. Allergic-directed therapies, including corticosteroids and antihistamines, were frequently reported, whereas ischemia-directed therapies and invasive procedures were inconsistently documented. Recovery was the predominant outcome (94%), while mortality was low (4%). Shock and cardiac arrest occurred in a minority of cases, and pooled estimates demonstrated only a weak association between severity markers and mortality. In conclusion, this systematic review and meta-analysis provide a quantitative synthesis of KS, demonstrating trigger-specific demographic patterns, consistent male predominance, and generally favorable outcomes, although reporting variability limits definitive inference.