Acute Mesenteric Artery Occlusion (Mesenteric Artery Occlusion): Causes, Mesenteric Infarction, Mesenteric Artery Stenosis, and Surgical Vascular Surgery for Acute Artery Occlusion

Mesenteric artery occlusion is one of the rare cerebrovascular emergencies in the abdomen, but it occurs more frequently in older adults. Epidemiologically, it is known that patients with atrial fibrillation, cardiac arrhythmias, or severe atherosclerosis are at particularly high risk. Acute mesenteric infarction is usually caused by an embolus that is dislodged from the heart and blocks a mesenteric artery. Arterial thrombosis also plays a role, especially in pre-existing vessels that are already narrowed. Recurrent abdominal pain after eating—known as angina abdominalis—may be an indication of an upstream mesenteric artery stenosis.

The etiology shows that vascular occlusion never occurs by chance but is almost always attributable to clearly identifiable risk factors. These include arterial circulatory disorders, chronic vascular diseases, and coagulation disorders such as an imbalance in anticoagulation. An acute mesenteric artery occlusion can also result from thrombosis when blood clotting is strongly activated locally. In rare cases, the occlusion is precipitated by trauma, abdominal surgery, or inflammatory processes. The etiology is therefore multifaceted and requires thorough investigation.

In clinical practice, mesenteric artery occlusion is often recognized late, as patients initially present with only nonspecific symptoms. These nonspecific symptoms make early diagnosis difficult and contribute to the severe course of the disease. Epidemiological data also show that many cases are not diagnosed until the advanced stage. The combination of embolism, thrombosis, and atherosclerotic processes underlies most cases. Without prompt intervention, severe ischemia of intestinal segments may occur.

A blood clot blocks the mesenteric artery and interrupts the vital blood supply to the intestine.

Symptoms often begin suddenly with severe abdominal pain, which initially appears disproportionately intense compared to the visible findings. This discrepancy is typical of mesenteric artery occlusion, as blood flow to the intestine is abruptly cut off. This is accompanied by nausea, vomiting, and increasing abdominal rigidity, indicating a developing acute abdomen. Some patients describe the pain as coming in waves, which can lead to misinterpretation at the onset. Early recognition of these symptoms can be life-saving.

As the condition progresses, the clinical picture deteriorates dramatically. Due to persistent ischemia, peristalsis in the affected bowel ceases to function, which can lead to bowel paralysis and gas-filled segments of the bowel. Progressive necrosis of the intestinal wall is a feared complication. In the event of a complete obstruction, toxins can enter the bloodstream and trigger sepsis. The rapid deterioration of vital signs requires immediate emergency measures.

Cases diagnosed too late often present with acute mesenteric infarction, characterized by severe abdominal distension and circulatory instability. The abdomen becomes increasingly hard, tender, and barely reacts to pressure. The combination of pain, vomiting, and circulatory disturbance is typical of the advanced clinical presentation. Since symptoms may begin nonspecifically, a high degree of vigilance is required. Early hospitalization can prevent long-term complications.

Diagnosis begins with a rapid clinical assessment, as mesenteric artery occlusion is an absolute medical emergency. The physician evaluates abdominal pain, guarding, and the clinical presentation of a possible acute abdomen. Blood tests often reveal elevated lactate levels due to ischemia. However, a physical examination alone is not sufficient, as the nonspecific symptoms can be misleading at first. Therefore, imaging studies are initiated early on.

CT angiography is the most important procedure for detecting mesenteric artery occlusion. It reveals whether a blood clot or an embolus is blocking the mesenteric artery and which segments of the intestine are affected. It also reveals stenoses or near-complete occlusions. Angiography also allows for an assessment of the stage of ischemia. In diagnostically challenging cases, conventional angiography may also be used.

Other procedures aid in establishing the diagnosis. When performed by experienced practitioners, duplex ultrasound can provide evidence of circulatory disturbances. In rare cases, diagnostic laparoscopy is indicated when findings are unclear and an acute mesenteric infarction cannot be ruled out. The diagnosis must be made quickly, as every moment lost reduces the chance of survival. The earlier the occlusion is detected, the better the prognosis.

Depending on the stage, treatment consists of a combination of medical and surgical measures. Initially, heparin is often administered for anticoagulation to halt the progression of thrombosis. In cases of embolic occlusion, removal of the blood clot is crucial. In the early phase, endovascular treatment—such as the interventional removal or dissolution of the clot—is an effective option. These procedures are primarily performed in specialized centers.

If the intestine is already damaged, immediate surgical intervention is performed. The affected section of the intestine is surgically resected to remove necrotic tissue and prevent the life-threatening consequences of ischemia. Depending on the findings, reconstruction of the affected artery may also be performed, for example, by creating a bypass. In extreme cases, a large area of intestinal tissue must be resected to prevent sepsis. Vascular surgical management is often complex and requires a specialized team.

In some cases, treatment can also be performed endovascularly, particularly if the diagnosis is made early. In this procedure, the mesenteric artery is assessed using angiography, and the occlusion is resolved—for example, by inserting a stent. The choice between surgical and interventional approaches depends on the clinical presentation, the timing of the diagnosis, and the extent of necrosis. Consistent follow-up care is crucial to prevent recurrent occlusions. This also includes long-term management of potential risk factors.

The prognosis depends largely on how quickly the mesenteric artery occlusion is detected and treated. With a very early diagnosis, therapy and intervention can restore blood flow before the intestine suffers irreversible damage. However, delays lead to necrosis, sepsis, and a greatly increased risk of death. The clinical picture deteriorates extremely rapidly, which is why every hour counts. Early intervention can drastically improve the chances of survival.

The course of an acute mesenteric infarction is often severe if the occlusion is detected late. Many patients do not arrive at the hospital until several hours later, which complicates treatment. In cases of advanced ischemia, the intestine often cannot be saved, and large sections must be resected. Despite surgery, the risk of complications remains high. Close monitoring in an intensive care unit is then necessary.

In the long term, the prognosis depends on the cause. Embolic occlusions have a better prognosis than those caused by atherosclerosis, as the artery is often unobstructed again after the blood clot is removed. Consistent management of risk factors such as hypertension, atrial fibrillation, or vascular disease is essential. Recurrent abdominal pain should always be investigated, as it may indicate mesenteric artery stenosis. Early preventive treatment can help prevent recurrent occlusions.