Mesenteric ischemia K55.0

Scott J. Boley was a pioneer in the field of mesenteric ischemia who extensively studied the entity of CMI as early as the 1960s (Menges 2022).

Mesenteric ischemia is an arterial or venous circulatory disorder of the intestine that can ultimately lead to permanent destruction of the affected section of the intestine (Heiss 2018).

Mesenteric ischemia can be acute or chronic (Herold 2019).

• Acute mesenteric ischemia (AMI):

It is divided according to the pathophysiological mechanism into:

- Arterial occlusive ischemia

- Non-occlusive ischemia

- Venous ischemia (Ghadimi 2022)

This is always an acute emergency (Herold 2019).

• Chronic mesenteric ischemia (CMI)

It is defined as insufficient perfusion of the gastrointestinal tract lasting longer than 3 months. It is most commonly caused by arteriosclerosis (Menges 2022).

In acute abdominal diseases, mesenteric ischemia occurs with a frequency of 0.4 % and is therefore rather rare (Häussinger 2018).

Mesenteric ischemia tends to occur in older people (Herold 2019). The incidence is approx. 2 - 3 affected persons per 100,000 people (Kasper 2015). Women are affected more frequently than men. However, a considerable number of unreported cases are suspected (Heiss 2018).

Acute mesenteric ischemia accounts for approx. 60%-70% of all mesenteric ischemia (Schwab 2019).

• Thromboembolic occlusive ischemia
  • Atrial fibrillation
  • Ventricular aneurysm
  • Artificial heart valve
  • Myocardial infarction
  • Rheumatism
  • Anterior stenosis or aneurysm (Ghadimi 2022)

• Thrombotic occlusive ischemia
  • Cardiovascular risk factors such as:
    • Diabetes mellitus
    • Arterial hypertension
    • Hyperlipidemia
  • Upstream aneurysm
  • Arteriosclerotic stenosis
  • Congenital or acquired coagulation disorder
  • Vasculitis
  • Dehydration (Ghadimi 2022)

• Non-occlusive ischemia
  • shock
  • Years of dialysis
  • Cardiac surgery
  • hypovolemia
  • catecholamines
  • beta-blockers
  • Digitalis
  • Critical general condition (Ghadami 2022)

• Mesenteric vein thrombosis:
  • Liver cirrhosis
  • Portal hypertension
  • Hematologic underlying disease
  • Malignancy
  • Pulmonary embolism
  • Deep vein thrombosis
  • Intra-abdominal infection
  • Heparin-induced thrombocytopenia I / II
  • Taking medications such as: Glucocorticoids, contraceptives
  • Vitamin K
  • Congenital or acquired thrombophilia such as: Antiphospholipid antibody syndrome, antithrombin III deficiency, protein C deficiency, protein S deficiency, prothrombin mutation, factor V Leiden mutation (Ghadami 2022)

In chronic mesenteric ischemia, arteriosclerosis affects the superior mesenteric artery (AMS) in more than 95% of cases, less frequently the coeliac trunk (Menges 2022).

The three visceral arteries, the truncus coeliacus and the superior and inferior mesenteric artery, play a role in mesenteric ischemia (Schwab 2019).

In acute mesenteric occlusion, the superior mesenteric artery is affected in 85% of cases. If a central occlusion occurs, gangrene develops from the jejunal flexure to the left colonic flexure. In peripheral occlusions, only segments of the small or large intestine may be affected (Schwab 2019).

If the arteriosclerotic stenosis of this artery develops slowly, circulation is ensured via collaterals. These stenoses therefore generally remain asymptomatic (Herold 2019).

Acute occlusions of the AMS, on the other hand, usually lead to an intestinal infarction, but can also remain clinically silent with good collateralization (Herold 2019).

In mesenteric ischemia, the superior mesenteric artery is most frequently affected, less frequently the coeliac trunk ((Menges 2022).

Patients primarily complain of

• sudden onset of crushing abdominal pain (in acute mesenteric ischemia)
• diffuse abdominal pain (in chronic mesenteric ischemia)
• often watery diarrhea with or without blood admixtures
• in the further course, improvement of symptoms after 6 - 8 hours with subsequent dramatic deterioration up to circulatory failure and sepsis (Häussinger 2018)

Acute mesenteric ischemia (AMI):

This can occur suddenly without any precursors as occlusive mesenteric ischemia (OMI). Around 70 % of cases are caused by embolisms, less frequently (in around 30 %) by arterial thrombosis. It can also represent the final stage of chronic mesenteric ischemia (Herold 2019).

The stages of acute mesenteric ischemia are divided into:

• Initial stage: Abdominal pain, diarrhea and shock symptoms predominate. This stage can last up to 6 hours (Schwab 2019).
• Low-pain interval: Also referred to as "lazy peace". This stage begins after 3-12 h and is characterized by dull abdominal pain, deterioration of the general condition and intestinal paralysis (Schwab 2019).
• End stage: The end stage occurs after approx. 12-24 h and is characterized by peritonitis, ileus, sepsis and multiple organ failure (Schwab 2019).

An acceptable treatment outcome can only be achieved in stages 1 and 2 (Schwab 2019).

Chronic mesenteric ischemia (CMI):

Due to the pronounced collateral circulation, symptoms of CMI usually only occur when more than one vessel is affected. The main symptom of CMI is angina abdominalis, in which cramp-like abdominal pain occurs approx. 20 - 30 min after eating and can last up to 2 h (Menges 2022).

Patients avoid eating and may lose a considerable amount of weight as a result (Menges 2022).

Clinically, a distinction is made between 4 different stages of chronic mesenteric ischemia (CMI):

- Stage I:

Here, the stenosis is found by chance arteriographically or by duplex sonography. There are no symptoms (Herold 2019).

- Stage II:

There is abdominal angina with intermittent, ischemia-related, postprandial abdominal pain (Herold 2019).

- Stage III:

In this stage, permanent abdominal pain and malabsorption syndrome are already present. Ischemic colitis may also develop (Herold 2019).

- Stage IV:

In stage IV, acute mesenteric obstruction with mesenteric infarction occurs. This stage progresses in 3 phases:

- 1st phase: In addition to nausea, there is also severe colicky pain in the middle abdomen (Herold 2019).

- 2nd phase: This phase is characterized by a relative pain-free interval that extends over several hours (Herold 2019).

- 3rd phase: This phase is characterized by paralytic ileus with peritonitis, clinical signs of an acute abdomen. There is defensive tension, diffuse pressure pain, shock and possibly bloody stools (Herold 2019).

Acute mesenteric ischemia is an emergency that requires rapid diagnosis (and treatment), as the ischemia tolerance of the intestine is only approx. 3 h (Herold 2019).

The medical history is of particular importance, as AKI can also represent the final stage of chronic mesenteric ischemia. The following diseases also represent a risk factor, such as:

• Heart disease, especially CHD, atrial fibrillation, heart failure
• Arterial hypertension
• Hypercholesterolemia
• Diabetes mellitus
• Taking ergotamine or digitalis
• Post aortic aneurysm surgery
• Post rectal amputation
• Circulatory shock (Herold 2019)
• Smoking (Heiss 2018)

The following examinations are recommended:

• Auscultation of the abdomen with the question of pulse-synchronous stenosis noises, especially in the upper abdomen (Herold 2019)
• ECG: Detection of atrial fibrillation (Herold 2019)
• Abdominal X-ray: This is primarily used to exclude free air and mechanical ileus (Häussinger 2018)
• Abdominal sonography: Here the focus should be particularly on stagnant bowel loops and free fluid (Herold 2019). In the case of mesenteric ischemia, an edematous thickened intestinal wall is seen in which the wall stratification is abolished (Häussinger 2018).
• Biphasic contrast agent CT (angio CT): This examination is the most important examination for detecting arterial or venous vascular occlusion (Herold 2019). It has a high sensitivity and specificity (Menges 2022).

If mesenteric ischemia is suspected, the following laboratory parameters in particular should be determined:

• Lactate
• CK
• LDH (often elevated, but non-specific)
• D- dimers: these are elevated in AMI (Herold 2019)

• Non-occlusive mesenteric ischemia (NOMI):

In this case, ischemia occurs in the area of the mesenteric arteries without arterial occlusion. This can be caused, for example, by a reduction in cardiac output with vasoconstriction of the splanchnic vessels, as can occur in heart failure, circulatory shock, myocardial infarction, chronic haemodialysis (Herold 2019), after cocaine overdose (Kasper 2015) or after cardiac surgery with the use of extracorporeal circulation. Digitalis has a favorable effect here (Herold 2019).

• Thrombosis of the V. portae and V. mesenterica

This is the cause of a mesenteric infarction in around 10 % of cases (Herold 2019).

The following complications can occur postoperatively after a bowel resection

• Short bowel syndrome (Herold 2019)
• Postoperative bleeding due to heparin administration
• Anastomotic insufficiency
• Short-bowel syndrome (Jauch 2013)

• Acute mesenteric ischemia with intestinal infarction:

If an intestinal infarction is detected, an immediate laparotomy is indicated (for details see "Surgical therapy" below).

• Chronic mesenteric ischemia:

If chronic mesenteric ischemia is detected, revascularization is generally indicated either as endovascular revascularization = ER or as open surgical revascularization = OR. (Menges 2022). For more details, see "Surgical therapy" below.

• Portal vein thrombosis:

A transjugular intrahepatic portosystemic shunt (TIPS) is created and catheter lysis is performed (Herold 2019).

• Non-occlusive mesenteric ischemia (NOMI):

In NOMI, catheter angiography is performed with selective intravenous application of vasodilators such as alprostadil or epoprostenol plus heparin into the superior mesenteric artery (Herold 2019).

Secondary prevention by optimizing cardiovascular risk factors also plays a major role. This includes both drug therapy and the optimization of personal lifestyle (Menges 2022).

All patients with CMI should receive secondary prophylaxis with an antiplatelet agent (for 3 - 12 months) and a statin (Menges 2022) such as acetylsalicylic acid or clopidogrel after endovascular revascularization (Schwab 2019).

• Chronic mesenteric ischemia:

Here, endovascular revascularization has the advantage due to low morbidity and lower costs. However, the disadvantages are an increased recurrence and reintervention rate (Menges 2022).

Surgical revascularization shows an initially increased perioperative morbidity, but has a better open rate (Menges 2022).

• Acute mesenteric ischemia or intestinal infarction:

As the ischemia tolerance of the bowel is only about 3 h, an exploratory laparoscopy should be performed immediately after diagnosis. Depending on the intraoperative findings, desobliteration, embolectomy, bypass surgery or stent PTA may be necessary. Necrosis of the bowel that has already occurred always necessitates bowel resection (Herold 2019).

The prognosis is largely determined by the length of time before surgery. In stage II, operations have a good prognosis, with an operative mortality rate of 5%. After 12 hours of ischemia, the mortality rate increases to 30% and after 24 hours to 85%. Concomitant diseases, the age of the patient and the length of the ischemic segment also play a role in the prognosis (Herold 2019).

The mortality rate for acute mesenteric ischemia is around 80% (Häussinger 2018).

If left untreated, mesenteric ischemia generally always leads to death (Heiss 2018).

To prevent mesenteric ischaemia, any risk of arteriosclerosis should be minimized by administering antiplatelet agents such as ASA. If atrial fibrillation is present, thromboembolism prophylaxis is indicated (Herold 2019).

Regular postoperative check-ups are absolutely essential. These should be carried out after 4 weeks, 6, 12, 18 and 24 months and then annually in the form of a duplex sonography. If restenosis is suspected, an angio-CT scan is recommended (Menges 2022).

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