Angiographic characteristics of the intermesenteric artery

PURPOSE

The literature reports the presence of the intermesenteric artery (IA), an anastomosis connecting the superior mesenteric artery (SMA) to the inferior mesenteric artery (IMA) in 9-18% of human cadaver dissections. This is the first study describing the morphological and demographic characteristics of the IA based on in vivo imaging.

METHODS

A total of 150 consecutive abdominal computed tomography (CT) angiographies of adult patients identified by sex and age were analyzed. The IA was assessed for its presence, point of origin, pathway, point of insertion, and diameter at its origin. The diameters of the SMA, IMA, and other arteries from which the IA originated and into which it inserted were measured by CT angiography using Radiant™ and Osirix MD™ software.

RESULTS

The IA was found in 17 (51.5%) of the females and 60 (51.3%) of the males. The diameters of the SMA and IMA were larger in the males than in the females, but there was no sex difference in the diameter of the IA. The diameter of the SMA was larger than that of the IMA, and the diameter of the IA was smaller than that of the other arteries evaluated. An IA connecting the SMA and IMA trunks was found in 25.9% of the cases, while other connections between the branches of those trunks through an IA occurred less frequently.

CONCLUSIONS

The intermesenteric artery is more frequently found than the literature refers and in most of cases directly connects the upper and lower arterial mesenteric circulations.

Hemodynamic Influences on Mesenteric Blood Flow in Shock Conditions

The gastrointestinal (GI) system, is most vulnerable to hypoperfusion among the splanchnic organs. Disturbed perfusion of the mesenteric area may lead to GI dysfunction, cause further injury to the patients and even vital outcomes. However, due to the limitation of detection methods, the hemodynamic influences on mesenteric blood flow in clinical practice are not fully understood. By elucidating the underlying mechanisms, we may be able to recognize disturbed GI perfusion and eventually GI dysfunction at an early phase. Thus, in this review, we will focus on situations where mesenteric blood flow is disturbed due to hemodynamic causes in shock conditions, and the present research status will be discussed. English language articles published before 2020 were identified through a computerized PubMed search using the terms "mesenteric, gastrointestinal, intestinal, splanchnic, blood flow, perfusion" and the cofactors. Relevant publications were retrieved and scanned for additional sources. There were few clinical trials focusing on mesenteric blood flow in shock patients. Most were animal experiments. Based on the best current evidence from these sources, we described the major influences on mesenteric blood flow in the context of physiologic accommodation, disease-related effects and the consequences of medical interventions related to shock conditions. During circulatory shock, sepsis, and medical interventions related to shock treatment, mesenteric blood flow changes and shows different features. We need to carefully consider these issues when making medical decisions, and more work needs to be done on early detection of GI hypoperfusion and its accurate correlation with GI dysfunction.

Systematic review: the impact of exercise on mesenteric blood flow and its implication for preoperative rehabilitation

BACKGROUND

Exercise in the preoperative period, or prehabilitation, continues to evolve as an important tool in optimising patients awaiting major intra-abdominal surgery. It has been shown to reduce rates of post-operative morbidity and length of hospital stay. The mechanism by which this is achieved remains poorly understood. Adaptations in mesenteric flow in response to exercise may play a role in improving post-operative recovery by reducing rates of ileus and anastomotic leak.

AIMS

To systematically review the existing literature to clarify the impact of exercise on mesenteric arterial blood flow using Doppler ultrasound.

METHODS

PubMed, EMBASE and the Cochrane library were systematically searched to identify clinical trials using Doppler ultrasound to investigate the effect of exercise on flow through the superior mesenteric artery (SMA). Data were extracted including participant characteristics, frequency, intensity, timing and type of exercise and the effect on SMA flow. The quality of each study was assessed using the Downs and Black checklist.

RESULTS

Sixteen studies, comprising 305 participants in total, were included. Methodological quality was generally poor. Healthy volunteers were used in twelve studies. SMA flow was found to be reduced in response to exercise in twelve studies, increased in one and unchanged in two studies. Clinical heterogeneity precluded a meta-analysis.

CONCLUSION

The weight of evidence suggests that superior mesenteric arterial flow is reduced immediately following exercise. Differences in frequency, intensity, timing and type of exercise make a consensus difficult. Further studies are warranted to provide a definitive understanding of the impact of exercise on mesenteric flow.