Surgical management of chronic mesenteric ischaemia (CMI)
CMI is predominantly secondary to atherosclerotic disease of the mesenteric arteries (superior and inferior mesenteric arteries, coeliac trunk). Its incidence is about 1-2% of all abdominal pathologies. Because of excellent collateralisation, extensive chronic occlusive processes of the mesenteric arteries can be compensated for a long time and remain asymptomatic. Symptoms typically only occur once at least two arteries are affected. The visceral 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 leads to failure of the collateral circulation and fatal mesenteric infarction with high mortality ("acute upon chronic visceral ischaemia").
A characteristic feature is the calcification close to the aorta, which obstructs the inflow into the otherwise still healthy arterial territory. Occlusions far from the ostium or over a long segment are less common and indicate other metabolic diseases (diabetes mellitus, chronic renal insufficiency, amyloidosis).
Akin to the Fontaine classification [1], the clinical presentation of CMI is classified into 4 stages:
Stage I | Asymptomatic, but with demonstrable pathology |
|---|---|
Stage II | Intermittent abdominal pain (abdominal claudication, intestinal angina) |
Stage III | Abdominal pain at rest |
Stage IV | Ischaemic tissue death (mesenteric infarction) |
In stage II and III there is an absolute indication for treatment. In asymptomatic patients (stage I) there is no indication for treatment, but patients should undergo close follow-up. Exceptions include asymptomatic patients eligible for concurrent reconstruction of the visceral arteries owing to an aortic aneurysm or aortoiliac occlusive disease.
Endovascular vs. open revascularisation (ER vs. OR)
A systematic literature review of CMI management comprising 43 papers with 1795 patients was presented in 2013 [2]. With ER, perioperative morbidity and mortality were lower than with OR, and there were no differences in survival between the two 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 who 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 the two 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 emphasised 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. in 2017 found a total of 14,811 revascularisations for CMI, of which 10,453 were ER and 4358 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 demonstrate that, with a stable OR rate, ER for CMI increased significantly without affecting population-based mortality due to CMI.
Another analysis of the NIS database from 2017 examined 4150 patients treated for CMI between 2007 and 2014 by endovascular (3206 = 77.2%) or open repair (944 = 22.8%).[5] After ER, severe cerebral and cardiac events as well as complications overall occurred significantly less frequently than after OR. In addition, ER was associated with lower costs and a shorter hospital stay.
A comparative series of OR vs. 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 influenced by the patients' comorbidities and revealed no significant difference between the two groups: five-year survival with OR 60%, with ER 57%. The authors concluded that it was not the type of revascularisation that was decisive for the long-term outcome, but patient age, diabetes mellitus, and renal insufficiency.
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 for ER (74%). Conversely, long-term survival after ER was significantly higher (95%) than after OR (78%). While perioperative mortality did not differ significantly, the length of hospital stay after ER was considerably shorter but associated with a higher rate of restenosis than OR. ER benefited most those patients with short lesions ≤ 2 cm and a higher surgical risk, whereas OR benefited patients with marked changes in the abdominal aorta and long, ostial lesions > 2 cm in the celiac trunk and the superior mesenteric artery.