Background
Although kidney insufficiency has been shown to be associated with increased risk of myocardial injury, benefit of coronary angiography (CAG) and revascularization remains uncertain, with implications on management strategies and outcomes. We aimed to compare rates of CAG and revascularization and subsequent risk of cardiovascular and kidney outcomes in hospitalized patients with myocardial injury and kidney dysfunction.

Methods
Retrospective cohort study encompassing hospitalized patients with myocardial injury i.e. elevated troponin I or T and an eGFR ≤60 ml/min/1.73 m2 identified between 2011 and 2021 in Danish national registers. 30-day odds for CAG were computed across granular eGFR-categories based on multiple logistic regression. Standardized one-year risks of cardiovascular and kidney outcomes including mortality were determined based on hazards obtained in multiple Cox regression.

Results
A total of 52,798 patients with myocardial injury were identified. CAG was performed in 14.3 % (n = 7549). 30-day odds ratios for CAG were 0.64 [0.60–0.68], 0.38 [0.34–0.42], 0.18 [0.14–0.22], and 0.35 [0.30–0.40] in patients with eGFR 31–45 ml/min/1.73 m2, eGFR 15–30 ml/min/1.73 m2 for eGFR<15 ml/min/1.73 m2 and chronic dialysis, respectively (eGFR 46-60 ml/min/1.73 m2 as reference). Median follow-up was 4.1 years. One-year mortality risk differences associated with CAG and revascularization (no CAG as reference) were −7.8 [−7.0; −8.7] and −9.1 [−8.4; −9.9] for eGFR 46-60 ml/min/1.73 m2; −7.0 [−5.7;-8–3] and −8.0 [−6.6; −9.5] for eGFR 31-45 ml/min/1.73 m2; −5.4 [−3.0; −7.2] and −5.2 [−2.2; −8.3] for eGFR 15-30 ml/min/1.73 m2; −8.8 [−3.1; −13.7] and −5.4 [3.1; −13.4] for eGFR<15 ml/min/1.73 m2; and −4.9 [−0.1; −9.7] and −4.2 [1.5; −9.2] for chronic dialysis, respectively.

Conclusion
Probability of CAG following myocardial injury declined with progressive kidney dysfunction. Overall, CAG was associated with lower mortality irrespective of kidney function and subsequent revascularization.