Impact of hypotonic hyponatremia on outcomes in patients undergoing transcatheter aortic valve replacement: a national inpatient sample

BACKGROUND: Transcatheter aortic valve replacement (TAVR) has emerged as a major therapeutic option for treating aortic stenosis. Hyponatremia is a common electrolyte disorder closely associated with adverse cardiovascular outcomes. However, large-scale studies investigating the impact of hypotonic hyponatremia on outcomes among TAVR patients are lacking. METHODS: We queried patients who underwent TAVR with concomitant hypo-osmolar hyponatremia (defined as a serum sodium concentration < 135 mEq/L with a serum osmolality < 280 mOsm/kg) using the National Inpatient Sample (2016-2021). Multivariate regression analysis and 1:1 propensity score matching (PSM) were performed to assess the associations between hypo-osmolar hyponatremia and in-hospital mortality and major adverse events (including acute kidney injury [AKI], acute myocardial infarction [AMI], and cardiogenic shock [CS]). Furthermore, sensitivity analysis was performed to assess the robustness of the findings. RESULTS: Among the total weighted national estimate of 370,680 patients who underwent TAVR, 13,865 (3.7%) had concomitant hypo-osmolar hyponatremia. These patients had a significantly increased risk of in-hospital mortality (aOR: 1.37; 95% CI: 1.08-1.74) and a greater likelihood of developing AKI (aOR: 3.39; 95% CI: 3.07-3.74), AMI (aOR: 3.20; 95% CI: 2.77-3.70), and CS (aOR: 2.96; 95% CI: 2.52-3.47). After PSM and sensitivity analysis, these associations remained significant. CONCLUSION: In TAVR patients, hypo-osmolar hyponatremia is associated with increased in-hospital mortality and adverse events, including AKI, AMI, and CS.