Risk assessment before transcatheter aortic valve implantation (TAVI) remains important, but widely applicable biomarkers are limited. This retrospective cohort study, published in Clinical Research in Cardiology assessed whether preprocedural Systemic Immune-Inflammation Index (SII) levels are associated with clinical outcomes in patients undergoing TAVI for severe aortic stenosis.

The analysis included 1822 patients treated between 2014 and 2023 at two centers in Germany, divided into derivation and validation cohorts. SII values were calculated from routine blood counts, and patients in the derivation cohort were grouped into tertiles based on SII levels.

In multivariable analysis, higher SII values were associated with increased rates of major adverse cardiovascular events (MACE) (hazard ratio [HR] 1.0001; 95% CI, 1.00001-1.00002; p=0.020) and stroke (HR 1.0003; 95% CI, 1.00002-1.00004; p<0.001). A generalized linear model showed that SII was positively associated with age (p=0.013) and C-reactive protein (CRP) (p<0.001), and inversely associated with mean aortic gradient (p=0.022) and hemoglobin (p=0.011).

Receiver operating characteristic (ROC) analysis identified an SII cut-off of 1204 for the validation cohort. Patients above this threshold had a higher risk of one-year all-cause mortality (HR 2.19; 95% CI, 1.59-3.02; p<0.001).

Higher preprocedural SII levels were associated with increased rates of cardiovascular events and mortality following TAVI.