While the first part of the treatment focuses on the underlying cause to relieve the low-flow state, a more direct treatment can be initiated to return blood flow to the splanchnic circulation. It is important to mention that the low-flow state, which usually precedes NOMI, cannot be treated with vasoconstrictors, since they would only worsen the condition by increasing resistance in peripheral splanchnic vessels. Furthermore, even when the precipitating event is corrected, the mesenteric vasospasm may still persist, indicating the importance of treatment continuation for this phenomenon [5, 6].

Two different treatment modalities exist: the first being intra-arterial application of vasodilators, the second being intravenous prostaglandin E1 (PGE1) administration. In the early 1970s, Boley et al. used intra-arterial papaverine (30–60 mg/h max. 4 h), a phosphodiesterase inhibitor that increases blood flow through smooth muscle relaxation, to improve bowel salvage [4]. Their group was able to obtain mortality rates of only 40 % by performing laparotomy only in patients who did not respond to treatment. This technique was practical since intra-arterial angiography was already used to differentiate between NOMI and OMI, giving the opportunity to directly engage intra-arterial treatment. Since in these days intra-arterial angiography was also used to follow up these patients and monitor the release of the vasospasm, continuation of vasodilators was possible. Alternative vasodilators for papaverine are phenoxybenzamine, tolazoline, and laevodosine, although these are not commonly used nowadays. In patients with poor or unstable conditions, repeated selective mesenteric angiography with papaverine may not be possible due to its complexity and invasiveness sometimes leading to acute tubular necrosis, local hematomas, and catheter dislodgement, especially in older patients [7, 8].

As mentioned in Chap. 25, computed tomography angiography (CTA) has now replaced angiography as the standard of reference in diagnosing mesenteric ischemia [9]. Additionally, CTA has a short examination time and the ability to rule out other causes of acute abdominal pain in a noninvasive way [10]. Consequently, an alternative for intra-arterial vasodilator therapy was found by administrating a continuous high dose of intravenous PGE1. PGE1 improves blood flow due to relaxation of vascular smooth muscle and inhibits reactive oxygen production due to ischemia [11]. Recently, two groups have tried this approach showing promising results by preventing acute NOMI in three out of three and eight out of nine patients using a PGE1 dose of 0.01–0.03 μg/kg/min for a maximum of 5 days (until improvement of abdominal symptoms) [7, 12]. Only one laparotomy was performed, and PGE1 infusion was deemed to be a safe treatment option. However, PGE1 also inhibits platelet aggregation. Therefore, particular care must be taken in elderly patients who are at risk for hemorrhage.

A laparotomy is only required when symptoms persist after initial treatment and/or when serum markers continue to increase. During surgery it is possible to use direct transcatheter infusion of papaverine into the superior mesenteric artery (SMA), which will restore blood flow within minutes. After restoration of blood supply, the bowel must be accurately reassessed. In order to do so, at least 20–30 min of reperfusion time should be allowed before viability can be determined via thorough exploration [13]. The bowel sections in which irreversible damage took place must then be resected [2]. It is important to realize that although blood flow may be restored with direct infusion of papaverine, the initial stimulus causing the ischemia still has to be treated to prevent further progression of ischemia.