Factors Associated with Invasive Coronary Angiography Use in Type 2 Myocardial Infarction: A Systematic Review with Narrative Synthesis

Background/Objectives: Type 2 myocardial infarction (T2MI) results from a myocardial oxygen supply–demand imbalance without acute coronary atherothrombosis, and the role of invasive coronary angiography in its management is undefined. Prior literature has largely compared T2MI to type 1 myocardial infarction (T1MI) rather than examining angiography selection within T2MI itself. This systematic review with narrative synthesis identified and synthesized factors associated with angiography utilization among T2MI patients, distinguishing adjusted from unadjusted evidence. Methods: PubMed, Embase, and ClinicalTrials.gov were searched for studies reporting patient or clinical characteristics associated with undergoing invasive coronary angiography among patients with T2MI, identified via multivariable regression, univariate comparison, or stratified baseline tables. Studies using angiography as an inclusion criterion, an event-risk outcome, or a randomized treatment assignment, or comparing T2MI to T1MI as groups without addressing within-T2MI factors, were excluded. This review was conducted in accordance with PRISMA 2020 guidance. Given clinical and methodological heterogeneity and no common effect-size metric across studies, findings were synthesized narratively without quantitative pooling. Results: Three studies met inclusion criteria (two large US administrative-data cohorts, n = 268,850 and n = 18,606 T2MI; one French two-center cohort, n = 224). Younger age was independently associated with greater odds of angiography in the largest cohort reporting age-specific estimates, with a monotonic decline in angiography utilization across advancing age strata; a second cohort’s unadjusted group comparison was directionally concordant, but its own multivariable estimate for age was internally inconsistent and is not treated as confirmatory. Chronic ischemic heart disease and heart failure were independently associated with higher odds of angiography, while chronic kidney disease, chronic obstructive pulmonary disease, peripheral vascular disease, and atrial fibrillation were independently associated with lower odds. Commercial insurance and Midwest or South United States residence were independently associated with higher odds in the single study assessing these factors. Cardiology consultation showed conflicting directions of adjusted association between the two studies reporting it. Conclusions: Selection for invasive angiography in T2MI is heterogeneous and inconsistently studied. Age was the only factor with cross-study directional support, and even that lacked confirmed adjusted concordance. Other factors were supported by single studies or conflicting findings, and no included study reported the bedside clinical variables plausibly driving real-time decisions. Certainty was very low for every factor examined (modified GRADE), underscoring the need for prospective study of angiography selection in T2MI.