We report a challenging case of a 68-year-old man with advanced gastric adenocarcinoma and severe dilated cardiomyopathy (DCM; EF 25%), highlighting perioperative management complexities to balance thrombosis prevention and bleeding risk. Preoperative evaluation revealed significant systolic dysfunction and coronary artery disease. A multidisciplinary team planned an open Roux-en-Y total gastrectomy to optimize oncological outcomes while minimizing anesthesia-related cardiac risks. Key interventions included heart-friendly anesthesia, continuous intraoperative cardiac monitoring, goal-directed fluid management, and dynamic anticoagulation adjustments. Postoperatively, the patient developed left leg intermuscular vein thrombosis, pneumonia, and gastrointestinal bleeding. Management included temporary discontinuation of enoxaparin, hemostatic therapy (tranexamic acid 1 g IV, batroxobin 5 IU IV, somatostatin 250 µg/h infusion), delirium control with dexmedetomidine 0.2–0.7 µg/kg/h and olanzapine 5 mg daily, and supportive transfusions (RBC 1.5 units, FFP 250 ml). Recovery was uneventful; follow-up at 3 months demonstrated stable cardiac function, no recurrent bleeding, and no disease recurrence. This case underscores the importance of individualized, dynamic perioperative strategies in patients with concurrent high-risk cardiovascular disease and advanced gastric malignancy, emphasizing careful anticoagulation, hemodynamic optimization, and multidisciplinary coordination to achieve favorable outcomes.