In this retrospective study, the investigators will analyze the correlation between cardiopulmonary bypass (CPB) time and acute gastrointestinal injury (AGI), and the outcomes of AGI in patients undergoing heart valve replacement.

Patients with heart valve diseases often have chronic cardiac insufficiency. Patients undergoing heart valve replacement with CPB are always complicated with gastrointestinal tract ischemia-reperfusion injury, which usually leads to AGI. AGI after cardiovascular surgery, especially in that use CPB, is associated with significant morbidity and an increase in peri-operative mortality. Prolonged CPB time could be predictive of AGI following heart valve replacement. This study is to analyze the correlation between CPB time and AGI, and the outcomes of AGI in patients undergoing heart valve replacement. The investigators hope that the benefits will include fewer patients becoming seriously postoperative AGI and mortality after cardiac surgery.

Inclusion Criteria:

• Patients undergoing heart valve replacement surgery with CPB
• Age > 18 years and ≤ 70 years

Exclusion Criteria:

• Patients combined with severe hematological disease, respiratory disease, and other critical diseases
• Patients had severe disorder of multiple systems and organs or severe pulmonary hypertension
• Have received major gastrointestinal surgery within 5 years
• Inflammatory bowel disease (IBD), including ulcerative colitis, Crohn's disease, or colitis
• Acute gastroenteritis
• Clostridium difficile or Helicobacter pylori infection
• Chronic constipation
• Peptic ulcer
• Polyps in the stomach or intestines
• Gastrointestinal neoplasms
• Abdominal hernia
• Irritable bowel syndrome
• Acute or chronic cholecystitis, hepatitis
• Patients who died during surgery
• Patients with digestive system tumors

Heart valve diseases

If patients permitted