An 83-year-old man was admitted for severe arteriosclerosis obliterans (ASO) of both legs. Severe left ventricular dysfunction (ejection fraction, 31%) with two-vessel coronary artery disease was diagnosed during preoperative evaluation. He underwent off-pump coronary artery bypass grafting (CABG) before the surgical correction of ASO. The operation time was 350 minutes, and he was transferred to the cardiac surgical intensive care unit (ICU) in an intubated state. He was extubated on the 1st postoperative day, and intravenous infusions of catecholamine were all discontinued. However, abdominal distension and vague abdominal tenderness without rebound were found on the 3rd postoperative day. Laboratory parameters revealed elevated white blood cell (WBC) count (26,000/μl) and C-reactive protein (CRP) level (20 mg/dl), but fairly normal lactate (1.1 mmol/L) and procalcitonin (0.47 ng/ml) levels. Plain abdominal radiography showed ileus with gaseous distension of the small bowel (Figure 1A). On the 4th postoperative day, about 200 ml of blood discharge abruptly appeared in the intraperitoneal drain, which was inserted after harvesting the right gastroepiploic artery during CABG. Computed tomographic angiography (CTA) showed diffuse small-bowel pneumatosis intestinalis and maintained perfusion of the celiac axis and superior mesenteric artery with mesenteric arterial enhancement, which suggested nonocclusive mesenteric ischemia (NOMI) (Figure 1B).

A bedside laparoscopy in the ICU was done 2 hours after the CTA scan. Trocars were placed through a subumbilical (12 mm, camera) and right lower quadrant (5 mm) incisions. Laparoscopic exploration showed a relatively pinkish distended small bowel without definite evidence of perfusion deficit except for a few focal ischemic spots (Figure 2). A Jackson-Pratt drain was placed through the right-lower-quadrant port site for further detection of abnormal fluids.

Postoperative care was focused on the optimization of perfusion through intravenous fluid resuscitation, and any vasoconstrictive agents were avoided. For bowel rest, the patient was placed on nil per os for 14 days followed by careful administration of liquid diet. Third-generation cephalosporin in combination with metronidazole was administered for 14 days to prevent bacterial translocation through the disrupted intestinal mucosa. The patient was transferred to the vascular surgery department for the treatment of ASO without any other complications, at 28 days after CABG.

A 68-year-old man was admitted to our institution for syncope. His medical history included laparoscopic left nephrectomy for a renal pelvis tumor 1 year previously. Severe aortic stenosis was diagnosed, and the patient underwent mechanical aortic valve replacement. The operative time was 200 minutes. The cardiopulmonary bypass and cardiac ischemic times were 95 and 65 minutes, respectively. He remained intubated and was transferred to the cardiac surgical ICU. He was extubated 5 hours after ICU admission. Oral anticoagulation combined with subcutaneous injection of low molecular weight heparin was started on the 1st postoperative day. He was transferred to the general ward on the next day.

The patient was readmitted to the ICU on the same day because of hemodynamically compromised atrial fibrillation. Abdominal distension and whole abdominal tenderness accompanied by a high fever up to 38.5°C were noted on the 3rd postoperative day. Simple abdominal radiography showed severe gaseous distension of the bowel loops (Figure 3A). CTA showed diffuse dilatation of the bowel loops with multifocal perfusion decrease and pneumatosis intestinalis without evidence of vascular compromise, suggestive of NOMI (Figure 3B). The WBC count was fair (7,990/μl), but the CRP (31.31 mg/dl) and lactate (6.3 mmol/L) levels were markedly elevated. The general surgery service recommended close observation. On the 5th postoperative day, serum lactate level decreased to the normal range (1.6 mmol/L), but the WBC count and CRP level were still high (9,390/μl and 41.97 mg/dl, respectively). The abdominal circumference was decreased by 4 cm; however, the abdomen was still distended, and pain and fever had not subsided. Follow-up CTA was performed, which demonstrated decreased perfusion of the small bowel with segmental nonenhancing bowel wall with air bubbles, suggestive of microperforation (Figure 3C).

The patient was transferred to the operating room and a diagnostic laparoscopy demonstrated small-bowel ischemia and pus-like fluid collection in the peritoneal cavity (Figure 4A). The operation was converted to median laparotomy and complete resection of the ischemic segments of the small bowel, primary end-to-end anastomosis, and creation of a temporary ileostomy were performed (Figure 4B). The length of the remnant small bowel was about 210 cm. Pathologic examination showed transmural infarction with bilateral involvement of the intestinal resection margins. The patient recovered well after laparotomy and was discharged home without any sequelae on the 35th postoperative day from the initial surgery, with a plan of ileostomy closure at 6 weeks after small-bowel resection.