The Relationship Between Preoperative International Normalized Ratio and Postoperative Major Bleeding in Total Shoulder Arthroplasty

Introduction: This study aimed to assess the relationship between preoperative international normalized ratio (INR) levels and major postoperative bleeding events after total shoulder arthroplasty (TSA). Methods: The American College of Surgeons National Surgical Quality Improvement Program database was queried for TSA from 2011 to 2020. A final cohort of 2405 patients with INR within 2 days of surgery were included. Patients were stratified into four groups: INR ≤ 1.0, 1.0 < INR ≤ 1.25, 1.25< INR ≤ 1.5, and INR > 1.5. The primary outcome was bleeding requiring transfusion within 72 hours, and secondary outcome variables included complication, revision surgery, readmission, and hospital stay duration. Multivariable logistic and linear regression analyses adjusted for relevant comorbidities were done. Results: Of the 2,405 patients, 48% had INR ≤ 1.0, 44% had INR > 1.0 to 1.25, 7% had INR > 1.25 to 1.5, and 1% had INR > 1.5. In the adjusted model, 1.0 < INR ≤ 1.25 (OR 1.7, 95% CI 1.176 to 2.459), 1.25 < INR ≤ 1.5 (OR 2.508, 95% CI 1.454 to 4.325), and INR > 1.5 (OR 3.200, 95% CI 1.233 to 8.302) were associated with higher risks of bleeding compared with INR ≤ 1.0. Discussion: The risks of thromboembolism and bleeding lie along a continuum, with higher preoperative INR levels conferring higher postoperative bleeding risks after TSA. Clinicians should use a patient-centered, multidisciplinary approach to balance competing risks.