Life-threatening bowel ischaemia can often be treated by endovascular means

Jussi Kärkkäinen

Acute mesenteric ischaemia can be successfully treated with endovascular therapy such as balloon angioplasty, according to research from the University of Eastern Finland.

The study also found that acute mesenteric ischaemia is a more common cause of abdominal pain among the elderly than generally thought, but also that it is difficult to diagnose before bowel damage develops. If left untreated, acute mesenteric ischaemia usually leads to gangrenous bowel, which is a life-threatening condition. Acute mesenteric ischaemia usually results from an occlusion of the superior mesenteric artery, typically caused by arteriosclerosis or embolism. Previously, the most common course of treatment was resection of gangrenous bowel—that is if anything at all could be done, as the overall mortality rate was over 80%.

From 2009 to 2013, a total of 66 patients with acute mesenteric ischaemia were treated at Kuopio University Hospital in Finland. Mesenteric revascularisation by endovascular therapy, such as balloon angioplasty or mechanical suction of the blood clot, was attempted in 50 of the patients, proving successful in 44 of the cases. Three of the patients underwent a surgical bypass after failed endovascular therapy. The mortality rate among the 66 patients was only 42%, which is a clear improvement compared to earlier treatment outcomes. Resection of gangrenous bowel was resorted to only in approximately one third of the patients, and more than half of them avoided surgery altogether.

Acute mesenteric ischaemia has so far been regarded as a very rare condition. The study analysed the incidence of the disease within one hospital district in eastern Finland and found that in patients over 75 years of age, the condition is in fact a more common cause of acute abdominal pain than ruptured abdominal aortic aneurysm or acute appendicitis. The mean age of the treated patients was 79 years. Acute mesenteric ischaemia is usually diagnosed using contrast enhanced CT, which is generally regarded as a very reliable diagnostic method. However, the study demonstrated that it is very challenging to make a definite diagnosis at the early stage of the disease. CT findings are often inconclusive, and they tend to get more conclusive only after permanent bowel damage has developed. For the patient’s prognosis, however, it is crucial to make a diagnosis before bowel damage develops.

Jussi Kärkkäinen, vascular surgeon and gastrointestinal surgeon, who presented the results in his doctoral dissertation, spoke to Interventional News about his recommendations to overcome the diagnosis-related challenges. “Many patients with acute mesenteric ischaemia, especially those with atherosclerotic aetiology, present with obscure symptoms such as vomiting and diarrhoea. The diagnosis can be incredibly difficult. Contrast-enhanced CT should be performed liberally to elderly patients with acute abdominal pain without fear of contrast-induced nephropathy if there is any suspicion of the condition. However, one-third of patients with acute on chronic mesenteric ischaemia in our study did not show any of the specific CT signs (thrombotic clot, decreased bowel wall enhancement or pneumatosis). Even so, nearly all patients had at least some abnormal intestinal findings (such as paralysis, mesenteric fat stranding, bowel wall thickening) in their CT examinations. The diagnosis is based on CT, laboratory and clinical findings, all together. The diagnostic accuracy of CT alone should not be overestimated.

“We hope that this study will raise awareness among surgeons and radiologists of the incidence of acute mesenteric ischaemia in older patients, as well as of the diagnostics-related challenges,” Kärkkäinen added.

Commenting on why balloon angioplasty offered benefit over surgery to treat acute mesenteric ischaemia, he noted: “These patients are elderly, fragile people with numerous risk factors for operative mortality. The endovascular approach offers the possibility of avoiding surgery in approximately half of acute mesenteric ischaemia patients. During our five-year study period, 3/4 of all patients with acute mesenteric ischaemia due to embolic or atherosclerotic arterial obstruction from a well-defined population of 250,000 inhabitants were treated with endovascular therapy and only 1/3 of those patients required bowel resection. The overall mortality was 42%. The mean age of the patients who received attempts at endovascular revascularisation was 79 years and their 30-day mortality was 32%. The oldest survivor was a 94-year old lady who was treated with endovascular aspiration of superior mesenteric artery embolus. Still, the caveat accompanying the endovascular-first approach is not to postpone laparotomy if the symptoms do not resolve quickly after revascularisation. Failure to resect dead bowel in time will lead to septic shock and even larger bowel necrosis or death.”

The findings from the study were originally published in the Journal of Gastrointestinal Surgery, European Journal of Radiology, and CardioVascular and Interventional Radiology.