Incidence and Pathophysiology of Gastrointestinal Bleeding During Mechanical Circulatory Support: A Retrospective Analysis Using Machine Learning Algorithms

Background: End-organ hypoperfusion from cardiopulmonary shock may require mechanical circulatory support (MCS). However, patients receiving MCS are at risk for hemorrhagic complications, including gastrointestinal (GI) bleeding. Examining potential risk factors for these complications improves clinical understanding. The purpose of this investigation was to study the risk for GI bleeding in MCS patients. Methods: Following IRB approval, patient characteristics, previously reported comorbidities, and the incidence of GI bleeding were reviewed from January 2017 to October 2023. Clinical variables underwent machine learning with autovalidation. Support Vector Machine modeling provided the best performance among the ensemble models tested. Results: Among 156 patients who underwent 284 MCS procedures, the incidence of GI bleeding was 6.0% (CI 3.3–10.4%). Following machine learning, insulin-dependent diabetes was associated with GI bleeding. The Receiver Operating Characteristic (ROC) curve demonstrated an area under the curve (AUC) of 0.85 with a misclassification rate of 7.5%. The relative risk for requiring major transfusion (>2 units packed red blood cells per episode) was 1.7 (CI 1.1–2.5). Most patients (87%), but not all, received unfractionated heparin therapy. Hospital length of stay was increased in patients with GI bleeding. Conclusion: Insulin-dependent diabetes was associated with increased risk for GI bleeding during MCS, and these patients more often required major transfusions. Further evaluation of continuous anticoagulation therapy is warranted. Knowledge derived from this analytical study may guide development of institutional protocols to improve care in this patient population.