Surgical management in chronic mesenteric ischemia (CMI).
CMI is mainly secondary to atherosclerotic disease of the mesenteric arteries (superior and inferior mesenteric arteries, celiac trunk). Its incidence is about 1-2% of all abdominal pathologies. Because of excellent collaterals, extensive chronic occlusive processes of the mesenteric arteries will be compensated for a long time and remain asymptomatic. The disease usually manifests once at least two arteries have been affected. The intestinal artery causing the symptoms is the superior mesenteric artery, which is involved in 85% of all cases. The problem in CMI is primarily its progression, which ultimately results in collateral circulation failure and fatal mesenteric infarction with high mortality ("acute upon chronic visceral ischemia").
A characteristic feature is calcification close to the aorta, which obstructs the inflow into the otherwise still healthy arterial distribution. Occlusions far from the arterial origin or over a long distance are less common and indicate other metabolic diseases (diabetes, chronic renal failure, amyloidosis).
Akin to the Fontaine classification [1], the clinical presentation of CMI is classified into 4 stages:
| Stage I: | Asymptomatic, but evidence of pathology |
| Stage II | Intermittent abdominal pain (abdominal claudication, intestinal angina) |
| Stage III | Abdominal pain at rest |
| Stage IV | Ischemic tissue death (mesenteric infarction) |
In stage II and III the indication for treatment is absolute. In asymptomatic patients (stage I) there is no indication for treatment, but patients should be followed up closely. Exceptions include asymptomatic patients eligible for concurrent intestinal artery repair in aortic aneurysm or aortoiliac occlusive disease.
Endovascular vs. open revascularization (ER vs. OR).
A systematic literature review of CMI management comprising 43 papers with 1795 patients was presented in 2013.[2] Perioperative morbidity and mortality were lower with ER than with OR, and there were no differences in survival between both procedures. In the OR group, primary and secondary patency rates were better and the recurrence rate was lower. The authors recommended ER as the first-line treatment in most patients with CMI, and OR should be limited to those patients who are either ineligible for ER or have low surgical risk and long life expectancy.
The first meta-analysis comparing ER versus OR dates back to 2015.[3] A total of 4255 patients underwent primary ER and 3110 primary OR. There was no statistically significant difference between both procedures for 30-day survival, postoperative complication rate, and long-term mortality. In contrast, the long-term patency rates clearly revealed the superiority of OR, which is why the authors of the meta-analysis referred to the open procedure as the gold standard in CMI, but still emphasized the benefits of initial management with ER because of its minimally invasive nature.
In the Nationwide Inpatient Sample (NIS) database from 2000 to 2012, Zettervall et al. found a total of 14,811 revascularizations for CMI in 2017, of which 10,453 were performed by ER and 4358 by OR.[4] Over the period studied, ER increased from 0.6 to 4.5/million population, while OR remained largely constant at 1-1.1/million population. At the same time, annual mortality due to CMI remained stable at 0.6-0.7 deaths/million population over the observation period. The figures show that with stable OR rates, ER in CMI increased significantly without affecting population-based mortality due to CMI.
Another analysis of the 2017 NIS database examined 4150 patients with CMI treated between 2007 and 2014 by endovascular (3206 = 77.2%) or open repair (944 = 22.8%).[5] After ER, the rate of severe cerebral and cardiac events and complications was significantly lower than after OR. In addition, ER was associated with lower costsand shorter hospital stay.
A series comparing OR with ER was published by the Mayo Clinic.[6] 187 patients underwent OR and 156 underwent ER. The follow-up period was 96 ± 54 months. Early mortality was almost identical at 2.7% (OR) and 2.6% (ER). Long-term survival was critically affected by patient comorbidities and revealed no significant difference between both groups: Five-year survival with OR 60%, with ER 57%. The authors concluded that it was not the type of revascularization that was critical for long-term outcome, but patient age, diabetes, and renal failure.
Between 2008 and 2012, Zacharias et al. treated a total of 215 vessels for CMI in 161 patients.[7] 116 patients (72%) underwent ER, and 45 (28%) underwent OR. Overall perioperative mortality was 6, 8%, and primary patency at 3 years was significantly higher for OR (91%) than ER (74%). Long-term survival on the other hand was significantly higher after ER (95%) than after OR (78%). While the perioperative mortality did not differ significantly, the length of stay in hospital after ER was significantly shorter but associated with a higher rate of restenosis when compared with OR. ER benefited most patients with short lesions ≤ 2 cm and a higher surgical risk, while OR benefited patients with marked changes in the abdominal aorta and long lesions > 2 cm near the origins of the celiac trunk and superior mesenteric artery.