Routine 4–6-week high-sensitivity C-reactive protein and subsequent cardiovascular outcomes after percutaneous coronary intervention: a landmark cohort study

Elevated high-sensitivity C-reactive protein (hsCRP) after percutaneous coronary intervention (PCI) is associated with adverse outcomes. It is less clear whether a value obtained at an ordinary early follow-up visit carries prognostic information in a routine-care population, and whether it adds to the admission measurement. Among 2,262 patients who underwent PCI between 2012 and 2021 at a single tertiary centre where laboratory tests including hsCRP are obtained routinely 4–6 weeks after PCI, 1,773 entered a 42-day landmark analysis after exclusion of those with major adverse cardiovascular events (MACE) or end of follow-up before day 42, missing admission or 4–6-week hsCRP or covariates, or 4–6-week hsCRP ≥ 20 mg/L. The primary endpoint was MACE (all-cause death, myocardial infarction, stroke, or any revascularization) through 730 days. The primary analysis examined natural log-transformed 4–6-week hsCRP per 1-standard deviation (SD) increase in a Cox model adjusted for clinical covariates (Model 1); Model 2 additionally included admission hsCRP. Median hsCRP was 1.39 mg/L at admission and 0.91 mg/L at 4–6 weeks. MACE occurred in 135 patients; Kaplan–Meier estimates at 730 days were 6.9%, 10.1%, and 12.3% across increasing hsCRP tertiles (log-rank P = 0.026). In Model 1, 4–6-week hsCRP was associated with MACE (hazard ratio [HR] per 1-SD, 1.20; 95% confidence interval [CI], 1.02–1.41; P = 0.029), without evidence of nonlinearity ( P = 0.750), whereas hsCRP ≥ 2 mg/L was not (HR, 1.18; 95% CI, 0.80–1.75). None of the lipid-related markers measured at the same visit was associated with MACE. After addition of admission hsCRP, the estimate for 4–6-week hsCRP was attenuated (HR, 1.13; 95% CI, 0.95–1.35; P = 0.158), and 4–6-week hsCRP did not improve model fit (likelihood-ratio P = 0.161) or discrimination (C-statistic, 0.640 to 0.642). Admission hsCRP alone showed a similar association (HR, 1.22; 95% CI, 1.04–1.43). In this low-inflammation routine-care cohort, 4–6-week hsCRP was modestly associated with 2-year MACE after clinical adjustment, but it did not provide prognostic information beyond the admission measurement. The prognostic information of the two measurements largely overlapped, and the incremental value of routine re-measurement was not established. Not applicable.