Pulmonary Risk Stratification in Open Thoracoabdominal Aortic Aneurysm Repair

Background/Objectives: The aim of this study was to assess whether preoperative pulmonary function testing (PFT) is related to postoperative complications after open thoracoabdominal aortic aneurysm (TAAA) repair. Methods: This study was conducted as a retrospective cohort analysis of 205 patients undergoing open TAAA repair (2006-2024) with preoperative spirometry and body plethysmography with at least one value available. Patients were classified by ventilation patterns: obstructive (n = 85, 45.2%), restrictive (n = 26, 14.1%), and hyperinflation (n = 56, 30.3%). Primary endpoints included in-hospital mortality, pulmonary complications (pneumonia, ARDS), and multi-organ outcomes. Associations were analyzed using chi-square and Spearman correlation tests and multivariable linear regression adjusted for age, smoking status, COPD, emergency operation, and time period. Results: Postoperative pulmonary complications occurred in 126 patients (61.5%), including pneumonia (46.8%) and ARDS (15.1%). Reduced vital capacity and FEV₁ expressed as a percentage of the lower limit of normal (%LLN) were related to postoperative pneumonia (p = 0.031 and p = 0.003) and ARDS (p = 0.038). Both obstructive and restrictive ventilation patterns were related to acute kidney injury after surgery (all KDIGO stage) (p = 0.044 and p = 0.043, respectively). Hyperinflation was related to atrial fibrillation (p = 0.039) and stroke (p = 0.034). FEV₁ < 2.0 L was related to increased mortality risk (p = 0.037), and FEV₁ < 1.5 L predicted acute kidney injury (p = 0.017), spinal cord ischemia (p = 0.035), and mortality (p = 0.023). Prolonged mechanical ventilation correlated with reduced preoperative lung function (VC %LLN ρ = -0.288, p = 0.002; FEV₁ %LLN ρ = -0.286, p = 0.001). During median follow-up of 6.35 years, patients in the highest FEV₁ quartile demonstrated substantially reduced long-term mortality (HR 0.27, 95% CI 0.10-0.73, p = 0.01). These associations between lower FEV₁ and VC (expressed as %LLN) with pneumonia, ARDS, in-hospital mortality, and prolonged ventilation remained significant after multivariable analysis. Conclusions: Preoperative pulmonary function assessment may help identify TAAA patients at increased risk of postoperative complications and mortality. Combining percentage-predicted spirometry, ventilation patterns, and hyperinflation markers may support individualized treatment selection, prehabilitation, and perioperative monitoring based on each patient's specific risk profile.