The effect of preprocedural hematological and biochemical parameters on in-hospital, 1-month and 1-year total mortality in patients undergoing transcatheter aortic valve implantation

Objective: Transcatheter aortic valve implantation (TAVI) is an alternative treatment modality to surgery in patients with high surgical risk. Surgical risk is determined by means of classic surgical risk scoring systems. The present study aims to assess parameters practically measured in blood samples collected from patients prior to TAVI procedure at all centers such as hematological and biochemical parameters and serum albumin/creatinine ratio, and investigate the predictive value of these parameters for postprocedural in-hospital, 1-month and 1-year survival. Furthermore, this study also aims to determine standalone risk factors likely to affect mortality, thereby contribute to improvement of risk scoring systems with predictive biomarkers that may decrease post-TAVI mortality in fragile and elderly patients at high surgical risk. Materials and Method: The present study included a total of 135 patients with symptomatic severe aortic stenosis (AS) considered to have high surgical risk and underwent TAVI at Dicle University Faculty of Medicine, Cardiology Clinic during 01.04.2013-31.12.2018. Transfemoral access was utilized for all patients. Echocardiographic measures of severe AS were determined based on relevant guidelines. Patients were evaluated for surgery by a cardiac team consisting of two cardiologists, two cardiovascular surgeons and an anesthetist. Key inclusion criteria included symptom presence, aortic valve area <1 cm2, mean aortic valve gradient >40 mmHg, STS (Society of Thoracic Surgeons) score ≥8 and EuroSCORE (European System for Cardiac Operative Risk Evaluation) II ≥8, functional capacity ≥II or contraindication for surgical aortic valve replacement (SAVR). Preprocedural clinical, laboratory and echocardiography data of patients undergoing TAVI were assessed retrospectively. Results: Of the 135 patients (mean age: 79.1±6.99 years, 58.5% females) included in the study, in-hospital death occurred in 16 patients while 15 patients died within the first 1 month and 37 patients died within 1 year from the procedure. Low serum albumin/creatinine ratio was found to be a standalone predictor of total all-cause mortality including in-hospital death and mortality at 1 month and 1 year. Similarly, low albumin level was a standalone predictor of total all-cause mortality for in-hospital death and 1-year mortality. Based on post-TAVI univariate analyses of the present study, elevated urea (p:0.01), low albumin (p:0.001), low serum albumin/creatinine ratio (p<0.001), low hematocrit (p:0.05) and increased neutrophils (p:0.05) were found to affect in-hospital mortality. Low serum albumin (p:0.01), low serum albumin/creatinine ratio (p:0.005) and decreased RBCs (p:0.04) were associated with mortality at 1 month from the TAVI procedure. Mortality within 1 year from TAVI was associated with low hemoglobin (p<0.001), low hematocrit (p<0.001), elevated urea (p<0.001), low serum albumin (p<0.001), low serum albumin/creatinine ratio (p<0.001), elevated creatinine (p:0.03), decreased lymphocytes (p:0.01), decreased RBCs (p:0.03) and high STS scores. Conclusion: In the present study, low serum albumin levels and low serum albumin/creatinine ratio were found to be independent variables of early and late mortality following TAVI. The finding that low serum albumin levels and low serum albumin/creatinine ratio in patients planned to undergo TAVI are standalone predictors of early and late mortality shows that malnutrition, fragility and chronic renal damage are parameters to take into consideration in this patient group. Keywords: Aortic stenosis, transcatheter aortic valve implantation, serum albumin/creatinine ratio, mortality