Long-Term Outcomes of Early Coronary Artery Disease Testing after New-Onset Heart Failure

BACKGROUND: Coronary artery disease (CAD) testing remains underutilized in patients with newly diagnosed heart failure (HF). The longitudinal clinical impact of early CAD testing has not been well-characterized. We investigated changes in clinical management and long-term outcomes after early CAD evaluation in patients with incident HF. METHODS: We identified Medicare patients with incident HF from 2006 to 2018. The exposure variable was early CAD testing within 1 month of initial HF diagnosis. Covariate-adjusted rates of cardiovascular interventions after testing, including CAD-related management, were modeled using mixed-effects regression with clinician as a random intercept. We assessed mortality and hospitalization outcomes using landmark analyses with inverse probability-weighted Cox proportional hazards models. Falsification end points and mediation analysis were employed for bias assessment. RESULTS: Among 309 559 patients with new-onset HF without prior CAD, 15.7% underwent early CAD testing. Patients who underwent prompt CAD evaluation had higher adjusted rates of subsequent antiplatelet/statin prescriptions and revascularization, guideline-directed therapy for HF, and stroke prophylaxis for atrial fibrillation/flutter than controls. In weighted Cox models, 1-month CAD testing was associated with significantly reduced all-cause mortality (hazard ratio, 0.93 [95% CI, 0.91–0.96]). Mediation analyses indicated that ≈70% of this association was explained by CAD management, largely from new statin prescriptions. Falsification end points (outpatient diagnoses of urinary tract infection and hospitalizations for hip/vertebral fracture) were nonsignificant. CONCLUSIONS: Early CAD testing after incident HF was associated with a modest mortality benefit, driven mostly by subsequent statin therapy. Further investigation on clinician barriers to testing and treating high-risk patients may improve adherence to guideline-recommended cardiovascular interventions.