Nonocclusive mesenteric ischemia following cardiothoracic surgery

Introduction

Nonocclusive mesenteric ischemia (NOMI) following cardiac surgery carries a high mortality. This disease is difficult to diagnose. Early diagnosis is thought to be of paramount importance as the only chance of improving the survival rate in these patients. Therefore, we were retrospectively studied all cases of NOMI to evaluate what were the sensitive markers and what were the risk factors contributing to the occurrence of NOMI.

Methods

We retrospectively reviewed 279 patients undergoing cardiothoracic surgery from August 2007 to July 2008. Six of these patients (2.2%) developed NOMI postoperatively and the data for them were retrospectively evaluated in detail.

Results

In all cases of NOMI, they were diagnosed at laparotomy. The mean age was 69.7 years (50 to 83 years old), and the male:female ratio was 1:1. One patient received off -pump coronary artery bypass surgery, and five underwent thoracic aortic surgery. Hemodialysis was initiated in one of six patients before operation, while the continuous hemodiafiltration was initiated in all patients postoperatively. After operation, high-dose catecholamines were necessary in five of six patients for long periods because of severe hypotension. In four of six patients, abdominal pain was the presenting symptom. The rest of two patients had a nonspecific presentation because they were ventilated and sedated. All patients presented abdominal distension and their abdominal X-rays showed paralytic ileus features. The serum values of AST, LDH, CK, and lactate were slightly elevated in most patients. Five of six patients died from septic shock and multiple organ failures, and the mortality rate of patients with NOMI was 83%. Potential risk factors contributing to the occurrence of NOMI and sensitive markers might be the following: continuous hemodiafiltration (6/6); hypotension (5/6); high-dose catecholamines (5/6); dehydration (6/6); abdominal pain (4/6); paralytic ileus patterns of abdominal X-rays (6/6).

Conclusions

The increase of NOMI incidence following cardiothoracic surgery might be related to continuous hemodiafiltration, hypotension, dehydration, and uses of high-dose catecholamines. Identification of patients at NOMI risk and prevention of hypovolemic hypotension and use of vasodilator may help to reduce the incidence of NOMI.