Long-term impact of baseline anaemia on clinical outcomes following percutaneous coronary intervention in stable angina

Background In patients with stable angina (SA), the clinical benefits of percutaneous coronary intervention (PCI) reside almost exclusively within the realm of symptomatic improvement rather than improvement in hard clinical endpoints. The benefits of PCI should always be balanced against its potential short-term and long-term risks. Common among these risks is the presence of anaemia and its interaction with poor clinical outcomes and increased morbidity; this study aims to elucidate the impact of anaemia on long-term clinical outcomes of this patient group. Methods From Danish national registries, we identified patients with SA treated with PCI who had a haemoglobin measurement maximum of 90 days prior to PCI procedure. Anaemia was defined as haemoglobin <130 and <120 g/L in men and women, respectively. Follow-up was up to 3 years after PCI, and Cox regression was used to estimate HRs with 95% CIs of hospitalisation due to bleeding, acute coronary syndrome (ACS) and all-cause mortality in patients with anaemia compared with patients without anaemia. Results Of 2837 included patients, 14.6% had anaemia prior to PCI. During follow-up, 93 patients (3.3%) had a bleeding episode, which was higher in patients with anaemia (5.8%) compared with patients without anaemia (2.8%). A total of 213 patients (7.5%) developed ACS, which was higher in patients with anaemia (10.6%) compared with patients without anaemia (7.0%). Furthermore, 185 patients (6.5%) died, with a mortality rate of 18.1% in patients with anaemia compared with 4.5% in patients without anaemia. In multivariable analyses, anaemia was associated with a significantly increased risk of bleeding (HR 1.69; 95% CI 1.04 to 2.73; P 0.033), ACS (HR 1.47; 95% CI 1.04 to 2.10; P 0.031) and all-cause mortality (HR 2.41; 95% CI 1.73 to 3.30; P <0.001). Conclusion Anaemia in patients with SA was significantly associated with bleeding, ACS and all-cause mortality following PCI.