Adenocarcinoma ; surgery ; Candidiasis ; etiology ; Cardiac Tamponade ; diagnosis ; etiology ; Echocardiography ; Electrocardiography ; Esophageal Fistula ; complications ; diagnostic imaging ; Fever ; etiology ; Gastrectomy ; Haemophilus Infections ; etiology ; Heart Diseases ; complications ; diagnostic imaging ; Humans ; Male ; Middle Aged ; Pericardial Effusion ; diagnostic imaging ; etiology ; Pericarditis ; diagnostic imaging ; etiology ; Postoperative Complications ; diagnostic imaging ; Staphylococcal Infections ; etiology ; Stomach Neoplasms ; surgery ; Streptococcal Infections ; etiology ; Tomography, X-Ray Computed