Mesenteric ischemia

Mesenteric ischemia is sudden blockage of blood flow to part of your small and large intestines, which may lead to gangrene and perforation (puncture) ¹⁾, ²⁾, ³⁾, ⁴⁾, ⁵⁾, ⁶⁾, ⁷⁾. Mesenteric ischemia occurs when there is a narrowing or blockage of one or more of the three mesenteric arteries that supply the small and large intestines. Sudden loss of blood flow to the intestines also known as acute mesenteric ischemia from a blood clot requires immediate surgery ⁸⁾. Mesenteric ischemia that develops over time also called chronic mesenteric ischemia is treated with angioplasty or open surgery ⁹⁾. Untreated, chronic mesenteric ischemia can become acute mesenteric ischemia or lead to severe weight loss and malnutrition. However, chronic mesenteric ischemia (CMI) often presents with vague abdominal pain that may be difficult to differentiate from other, more common causes of abdominal pain ¹⁰⁾, ¹¹⁾, ¹²⁾, ¹³⁾.

The most common risk factors for acute mesenteric ischemia include:

• Atrial fibrillation (AF or AFib) — an irregular and often very rapid heart rhythm.
• Congestive heart failure — a condition in which the heart muscle doesn’t pump blood as well as it should.
• Recent vascular surgery.

The most common risk factors for chronic mesenteric ischemia include:

• Type 2 diabetes.
• High cholesterol levels.
• High blood pressure.
• Artery disease.
• Smoking.
• Obesity.
• Older age.

Figure 1. Mesenteric artery

Figure 2. Superior mesenteric artery and its branches

Figure 3. Inferior mesenteric artery and its branches

Mesenteric ischemia causes

Both acute and chronic mesenteric ischemia are caused by a decrease in blood flow to the small and large intestines. Acute mesenteric ischemia is most commonly caused by a blood clot in the main mesenteric artery. The blood clot often starts in the heart. Chronic mesenteric ischemia is most commonly caused by a buildup of fatty deposits, called plaque, that narrows the arteries.

The arteries that supply blood to your intestines run directly from the aorta. The aorta is the main artery from your heart. Hardening of the arteries occurs when fat, cholesterol, and other substances build up in the walls of arteries. This is more common in smokers and in people with high blood pressure or high blood cholesterol. This narrows the blood vessels and reduces blood flow to the intestines. Like every other part of the body, blood brings oxygen to the intestines. When the oxygen supply is slowed, symptoms may occur.

3 major vessels serve the abdominal contents:

• Celiac trunk: Supplies the esophagus, stomach, proximal duodenum, liver, gallbladder, pancreas, and spleen
• Superior mesenteric artery (SMA): Supplies the distal duodenum, jejunum, ileum, and colon to the splenic flexure (see Figures 1 and 2)
• Inferior mesenteric artery (IMA): Supplies the descending colon, sigmoid colon, and rectum (see Figures 1 and 3)

Collateral vessels are abundant in the stomach, duodenum, and rectum; these areas rarely develop ischemia. The splenic flexure is a watershed between the superior mesenteric artery and inferior mesenteric artery and is at particular risk of ischemia. Note that acute mesenteric ischemia is distinct from ischemic colitis, which involves only small vessels and causes mainly mucosal necrosis and bleeding.

Mesenteric blood flow may be disrupted on either the venous or arterial sides. In general, patients > 50 are at greatest risk and have the types of occlusions and risk factors. However, many patients have no identifiable risk factors.

The blood supply to the intestines may be suddenly blocked by a blood clot (embolus). The clots most often come from the heart or aorta. These clots are more commonly seen in people with abnormal heart rhythm.

Both acute and chronic mesenteric ischemia are caused by a decrease in blood flow to your intestines. Acute mesenteric ischemia is most commonly caused by a blood clot in the main mesenteric artery. The blood clot often originates in the heart. The chronic form is most commonly caused by a buildup of plaque that narrows the mesenteric arteries.

Mesenteric ischemia has multiple causes. The most common are:

• Mesenteric Arterial Embolism (> 40%): Arterial embolism is a blood clot or piece of atherosclerotic plaque material (the buildup of cholesterol and other fatty materials in an artery) that travels from its origin in the heart or aorta to lodge in the smaller arteries (in this case those of the intestines). Predisposing factors include cardiomyopathy, atrial fibrillation, recent angiography, underlying vasculitis and valvular disorders.
• Mesenteric Arterial Thrombosis (30%): Arterial thrombus is a blood clot that forms spontaneously in the arteries or veins, including those of the intestines, blocking flow ¹⁴⁾. Predisposing factors include patients with atherosclerosis, peripheral arterial disease, hypercoagulability, estrogen therapy, and prolonged hypotension.
• Mesenteric Venous Thrombosis (15%). Mesenteric venous thrombosis causes increases in the resistance of mesenteric venous blood flow. Patients who have local intra-abdominal inflammatory processes (such as inflammatory bowel disease) are at higher risk for this. Patients who are hypercoagulable (in other words those with heritable and acquired thrombophilias and malignancies) are also at a higher risk.
  
• Nonocclusive Mesenteric Ischemia (NOMI) (15%): Sometimes flow is not blocked completely but is simply too low because of low heart output (as in heart failure or shock), “spasm” of the superior mesenteric artery (SMA) or because certain drugs (such as cocaine) narrow the blood vessels ¹⁵⁾. In general, people older than 50 years are at greatest risk. Risk factors include peripheral artery disease, septic shock, vasoconstrictive medications (such as digoxin), cocaine abuse, hemodialysis, among many other conditions.
  

Blockage of blood flow for more than 6 hours can cause the affected area of intestine to die, allowing intestinal bacteria to invade the person’s system. Shock, organ failure, and death are likely if intestinal death occurs.

Risk factors for mesenteric ischemia

• Arterial embolus (> 40%): Coronary artery disease, heart failure, valvular heart disease, atrial fibrillation, history of arterial emboli
• Arterial thrombosis (30%): Generalized atherosclerosis. If you’ve had other conditions caused by atherosclerosis you have an increased risk of intestinal ischemia. These conditions include decreased blood flow to your heart (coronary artery disease), legs (peripheral vascular disease) or the arteries supplying your brain (carotid artery disease).
• Venous thrombosis (15%): Hypercoagulable states, inflammatory conditions (eg, pancreatitis, diverticulitis), trauma, heart failure, renal failure, portal hypertension, decompression sickness
• Nonocclusive ischemia (15%): Low-flow states (eg, heart failure, shock, cardiopulmonary bypass), splanchnic vasoconstriction (eg, vasopressors, cocaine)
• Age. People older than 50 are more likely to develop intestinal ischemia.
• Smoking. Cigarettes and other forms of smoked tobacco increase your risk of intestinal ischemia.
• Heart and blood vessel problems. Your risk of intestinal ischemia is increased if you have congestive heart failure or an irregular heartbeat such as atrial fibrillation. Blood vessel diseases that result in irritation and inflammation of veins and arteries (vasculitis) may also increase risk.
• Medications. Certain medications may increase your risk of intestinal ischemia. Examples include birth control pills and medications that cause your blood vessels to expand or contract, such as some allergy medications and migraine medications.
• Blood-clotting problems. Diseases and conditions that increase your risk of blood clots may increase your risk of intestinal ischemia. Examples include sickle cell anemia and the Factor V Leiden mutation.
• Other health conditions. For example, having high blood pressure, diabetes or high cholesterol can increase the risk of intestinal ischemia.
• Recreational drug use. Cocaine and methamphetamine use have been linked to intestinal ischemia.

The most common risk factors for acute mesenteric ischemia include:

• Atrial fibrillation (AF or AFib) — an irregular and often very rapid heart rhythm.
• Congestive heart failure — a condition in which the heart muscle doesn’t pump blood as well as it should.
• Recent vascular surgery.

The most common risk factors for chronic mesenteric ischemia include:

• Type 2 diabetes.
• High cholesterol levels.
• High blood pressure.
• Artery disease.
• Smoking.
• Obesity.
• Older age.

Mesenteric ischemia prevention

The following lifestyle changes can reduce your risk for narrowing of the arteries:

• Get regular exercise.
• Follow a healthy diet.
• Get heart rhythm problems treated.
• Keep your blood cholesterol and blood sugar under control.
• Quit smoking.

Mesenteric ischemia symptoms

At first, the person has severe abdominal pain, usually developing suddenly, but only mild pain occurs when the doctor presses on the abdomen during the examination (unlike in disorders such as appendicitis or diverticulitis, in which pressing makes the pain much worse). Later, as the intestine starts to die, the doctor’s examination of the abdomen causes more severe pain.

Acute mesenteric ischemia symptoms

Symptoms of sudden acute mesenteric ischemia due to a traveling blood clot include:

• Sudden severe abdominal pain
• Diarrhea
• Nausea and vomiting
• Urgent need to have a bowel movement
• Fever

Patients with acute mesenteric ischemia may initially present with classic “pain out of proportion to examination”, with an epigastric bruit; many, however, do not ¹⁶⁾. Other patients may have tenderness with palpation on examination owing to peritoneal irritation caused by full-thickness bowel injury. This finding may lead the physician to consider diagnoses other than acute mesenteric ischemia ¹⁷⁾. In a patient with abdominal pain of acute onset, it is critical to assess the possibility of atherosclerotic disease and potential sources of an embolus, including a history of atrial fibrillation and recent myocardial infarction ¹⁸⁾. During the examination, the patient’s description of the history and symptoms can be unclear because of changes in mental status, particularly if he or she is elderly ¹⁹⁾.

Differentiation between arterial and venous obstruction is not always simple; however, patients with mesenteric venous thrombosis, as compared with those with acute arterial occlusion, tend to present with a less abrupt onset of abdominal pain ²⁰⁾. Risk factors for venous thrombosis that should be evaluated include a history of deep venous thrombosis, cancer, chronic liver disease or portal-vein thrombosis, recent abdominal surgery, inflammatory disease, and thrombophilia ²¹⁾.

Chronic mesenteric ischemia symptoms

Symptoms caused by chronic mesenteric ischemia due to gradual hardening of the mesenteric arteries include:

• Abdominal pain that starts about 30 minutes after eating
• Pain that worsens over an hour
• Pain that goes away within one to three hours
• Diarrhea

Patients with chronic mesenteric ischemia can present with a variety of symptoms, including abdominal pain, postprandial pain, nausea or vomiting (or both), early satiety, diarrhea or constipation (or both), and weight loss ²²⁾. A detailed inquiry into the abdominal pain and its relationship to eating can help with the diagnosis. Abdominal pain 30 to 60 minutes after eating is common ²³⁾ and is often self-treated with food restriction, resulting in weight loss and, in extreme situations, fear of eating, or “food fear”. Postprandial pain may, however, be associated with other intraabdominal processes, including biliary disease, peptic ulcer disease, pancreatitis, diverticular disease, gastric reflux, irritable bowel syndrome, and gastroparesis.

An extensive gastroenterologic workup, possibly including cholecystectomy and upper and lower endoscopy — tests that are often negative in patients with chronic mesenteric ischemia — is generally carried out before the diagnosis is made ²⁴⁾. An important distinction is that many of these alternative processes do not involve weight loss, whereas it is common in cases of mesenteric ischemia ²⁵⁾, ²⁶⁾. Since older age and a history of smoking are common in these patients, cancer is often considered, and concern about it may delay the identification of chronic mesenteric ischemia ²⁷⁾. Furthermore, particularly in the case of elderly women with a history of weight loss, dietary changes, and systemic vascular disease, chronic mesenteric ischemia must be seriously considered and evaluated appropriately ²⁸⁾.

Mesenteric ischemia complications

If not treated promptly, acute mesenteric ischemia can lead to:

• Sepsis. This potentially life-threatening condition is caused by the body releasing chemicals into the bloodstream to fight infection. In sepsis, the body overreacts to the chemicals, triggering changes that can lead to multiple organ failure.
• Irreversible bowel damage. Insufficient blood flow to the bowel can cause parts of the bowel to die (gangrene).
• Death. Both of the above complications can lead to death.

People with chronic mesenteric ischemia can develop:

• Fear of eating. This occurs because of the after-meal pain associated with the condition.
• Unintentional weight loss. This can occur as a result of the fear of eating.
• A hole through the wall of the intestines (perforation). A perforation can develop, which can cause the contents of the intestine to leak into the abdominal cavity. This may cause a serious infection (peritonitis).
• Scarring or narrowing of your intestine. Sometimes the intestines can recover from ischemia, but as part of the healing process the body forms scar tissue that narrows or blocks the intestines. This occurs most often in the colon. Rarely this happens in the small intestines.
• Acute-on-chronic mesenteric ischemia. Symptoms of chronic mesenteric ischemia can progress, leading to the acute form of the condition.

Mesenteric ischemia diagnosis

If the person has typical symptoms of acute mesenteric ischemia or if the abdomen is very tender, doctors usually take the person to surgery straight away.

If the diagnosis of acute mesenteric ischemia is not clear, doctors do CT angiography (a special CT scan using radiopaque dye injected in an arm vein to produce images of blood vessels) to look for swelling of the intestines or blockages in the arteries that supply blood to the intestines ²⁹⁾, ³⁰⁾, ³¹⁾. In addition to providing information about the vasculature, CT angiography (CTA) can indicate potential sources of emboli, other intraabdominal structures and pathologic processes, and abnormal findings such as the lack of enhancement or the thickening of the bowel wall and mesenteric stranding associated with diminished blood flow. More ominous pathological findings, including pneumatosis, free intraabdominal air, and portal venous gas, may also be noted ³²⁾.

Catheter angiography, which was previously considered to be the standard method of diagnosis of mesenteric ischemia, has become a component of initial therapy. Catheter angiography with selective catheterization of mesenteric vessels is now used once a plan for revascularization has been chosen. Single or complementary endovascular therapies, including thrombolysis ³³⁾, angioplasty with or without stenting ³⁴⁾ and intraarterial vasodilation ³⁵⁾ are then combined to restore blood flow. Catheter angiography can also be used to confirm the diagnosis before open abdominal exploration is undertaken ³⁶⁾

In some cases, you may need surgery to find and remove damaged tissue. Opening the abdomen allows diagnosis and treatment during one procedure.

Despite the many investigations conducted to date, there are no specific blood tests to indicate intestinal ischemia ³⁷⁾, ³⁸⁾. Tests for markers of nutritional status, such as albumin, transthyretin, transferrin, and C-reactive protein, are the only studies of value in cases of chronic mesenteric ischemia, since they can be used to assess the degree of malnutrition before revascularization is undertaken.

Mesenteric ischemia treatment

If mesenteric ischemia is diagnosed during surgery, the blood vessel blockage can sometimes be removed or bypassed, but other times the affected intestine must be removed.

If mesenteric ischemia is diagnosed during CT angiography, doctors may try to relieve the blockage in the blood vessels using angiography. In angiography, a small flexible tube (catheter) is threaded through the artery in the groin and into the arteries of the intestines. If a blockage is seen during angiography, sometimes it can be opened by injecting certain drugs, suctioning out a blood clot using a special angiography catheter, or inflating a small balloon within the artery to widen it and then placing a small tube or manufactured mesh (stent) to keep it open. If doctors cannot successfully open the blockage using these procedures, the person needs surgery to open the blockage or to remove the affected portion of the intestine.

Patients with acute mesenteric ischemia require intensive care and should be placed in the hospital’s intensive care unit after surgery. Most patients require a “second-look laparotomy” 24 to 48 hours after mesenteric revascularization, as it is important to re-evaluate the bowel. Unless contraindicated, many people need to be on long-term systemic anticoagulation prevent blood clotting after their hospital stay. If a mesenteric artery stent is placed, it is important to have periodic surveillance of the stent (either with duplex ultrasound or CT angiography), although there have been few studies done on specific surveillance intervals.

Early medical therapy

Fluid resuscitation with the use of isotonic crystalloid fluids and blood products as needed is a critical component of initial care. Serial monitoring of electrolyte levels and acid–base status should be performed, and invasive hemodynamic monitoring should be implemented early ³⁹⁾; this is especially true in patients with acute mesenteric ischemia, in whom severe metabolic acidosis and hyperkalemia can develop as a result of infarction ⁴⁰⁾. These conditions may create the potential for rapid decompensation to a systemic inflammatory response or progression to sepsis.

In patients with hemodynamic instability, it is imperative to carefully adjust fluid volume while avoiding fluid overload and to use pressor agents only as a last resort. The fluid-volume requirement can be very high, especially after revascularization, because of the extensive capillary leakage; as much as 10 to 20 liters of crystalloid fluid may be required during the first 24 hours after the intervention ⁴¹⁾.

Heparin treatment should be initiated as soon as possible in patients who have acute mesenteric ischemia or an exacerbation of chronic mesenteric ischemia. Vasodilators may play a role in care, particularly in combating persistent vasospasm in patients with acute ischemia after revascularization ⁴²⁾. Epithelial permeability increases during acute mesenteric ischemia as high bacterial antigen loads trigger inflammatory pathways ⁴³⁾, ⁴⁴⁾ and the risk of bacterial translocation and sepsis increases ⁴⁵⁾.

Antibiotics can lead to resistance and alterations in bacterial flora; however, their use has been associated with improved outcomes in critically ill patients ⁴⁶⁾, ⁴⁷⁾. In general, the high risk of infection among patients with acute mesenteric ischemia outweighs the risks of antibiotic use, and therefore broad-spectrum antibiotics should be administered early in the course of treatment.

Oral intake should be avoided in patients with acute mesenteric ischemia, since it can exacerbate intestinal ischemia ⁴⁸⁾. In patients with chronic mesenteric ischemia, in contrast, enteral nutrition (as long as it does not cause pain) or parenteral nutrition should be considered in order to improve perfusion by means of mucosal vasodilation and to provide nutritional and immunologic benefits ⁴⁹⁾.

Acute mesenteric artery ischemia treatment

Surgery may be necessary to remove a blood clot, to bypass an artery blockage, or to repair or remove a damaged section of intestine. Treatment also may include antibiotics and medications to prevent clots from forming, dissolve clots or dilate blood vessels.

If angiography is done to diagnose the problem, it may be possible to remove a blood clot or to open up a narrowed artery with angioplasty at the same time. A stent also may be placed in your artery to help keep it open.

Endovascular procedures

Endovascular procedures can theoretically restore perfusion more rapidly than can open repair and may thus prevent progression of mesenteric ischemia to bowel necrosis. Although the use of endovascular techniques is becoming more common, the comparative data on the results with the two approaches in patients with acute mesenteric ischemia are insufficient to show a clear advantage of one approach over the other ⁵⁰⁾, ⁵¹⁾, ⁵²⁾.

The largest review of endovascular interventions involved 70 patients with acute mesenteric ischemia. Treatment was considered to be successful in 87% of the patients, and in-hospital mortality was lower among those who underwent endovascular procedures than among those who underwent open surgery (36% vs. 50%). However, patients who presented with more profound visceral ischemia may have been assigned to open revascularization. These and other data ⁵³⁾, ⁵⁴⁾ suggest that the use of endovascular procedures for acute mesenteric ischemia is becoming more common; the use of these procedures increased from 12% of cases in 2005 to 30% of cases in 2009 ⁵⁵⁾. These data also show that endovascular intervention may be most appropriate for patients with mesenteric ischemia that is not severe and those who have severe coexisting conditions that place them at high risk for complications and death associated with open surgery.

An acute occlusion can be treated with a combination of endovascular interventions, with initial treatment aimed at rapidly restoring perfusion to the viscera, most often by means of mechanical thrombectomy or angioplasty and stenting. Thrombolysis is safe and very effective as an adjunct procedure to remove the additional burden of thrombus in patients without peritonitis, and it can be especially helpful in restoring perfusion to occluded arterial branches. These techniques can be effective in treating both embolic and thrombotic occlusions ⁵⁶⁾, ⁵⁷⁾. Although the use of endovascular therapy for acute mesenteric ischemia precludes direct assessment of bowel viability, 31% of patients who received endovascular therapy in one series were spared laparotomy ⁵⁸⁾. If endovascular-only therapy is pursued, close monitoring is compulsory, and any evidence of clinical deterioration or peritonitis necessitates operative exploration performed on an emergency basis because 28 to 59% of these patients will ultimately require bowel resection ⁵⁹⁾, ⁶⁰⁾.

Open surgical repair

The goals of open surgical repair for acute mesenteric ischemia are to revascularize the occluded vessel, assess the viability of the bowel, and resect the necrotic intestine ⁶¹⁾. Emboli that cause acute occlusion typically lodge within the proximal superior mesenteric artery and have a good response to surgical embolectomy. If embolectomy is unsuccessful, arterial bypass may be performed. This procedure is ideally carried out with autologous grafting, typically of a single vessel distal to the occlusion. However, if distal perfusion remains impaired, local intraarterial doses of thrombolytic agents can be administered.

A hybrid option, retrograde open mesenteric stenting, involves local thromboendarterectomy and angioplasty, followed by retrograde stenting ⁶²⁾, ⁶³⁾. This approach reduces the extent of surgery while allowing for direct assessment of the bowel. At this time, however, it is not commonly used, and evidence regarding its outcomes is limited ⁶⁴⁾.

After revascularization, the bowel and other intraabdominal organs are assessed for viability and evidence of ischemia. Frankly ischemic bowel is resected, whereas areas that suggest the possible presence of ischemia may be left for evaluation at a follow-up, or “second-look,” operation. Up to 57% of patients ultimately require further bowel resection ⁶⁵⁾, ⁶⁶⁾, ⁶⁷⁾, including nearly 40% of patients who undergo a second-look operation  ⁶⁸⁾, ⁶⁹⁾. Short-term mortality after open revascularization ranges from 26 to 65% and rates are higher among patients with renal insufficiency, older age, metabolic acidosis, a longer duration of symptoms, and bowel resection at the time of a second-look operation ⁷⁰⁾, ⁷¹⁾, ⁷²⁾, ⁷³⁾.

Chronic mesenteric artery ischemia treatment

Treatment requires restoring blood flow to your intestine. Your surgeon can bypass the blocked arteries or widen narrowed arteries with angioplasty or by placing a stent in the artery.

Decisions regarding the most appropriate approach to patients with chronic mesenteric ischemia should weigh the morphologic features of the lesion and the patient’s state of health against the short- and long-term risks and benefits of the procedure. In most centers, endovascular therapy is considered to be first-line therapy, particularly in patients with short, focal lesions. The risks associated with future reintervention may outweigh the immediate risks of open surgery among most patients with chronic mesenteric ischemia. In contrast, open repair may be a preferable option for younger, lower-risk patients with a longer life expectancy or for those whose lesions are not amenable to endovascular techniques.

Open repair, which was formerly considered to be the standard in such cases, has been surpassed in recent years by endovascular repair, which is now used in 70 to 80% of initial procedures ⁷⁴⁾. Because angioplasty alone has poor patency and is associated with poor long-term symptom relief, stenting is used most often ⁷⁵⁾, ⁷⁶⁾. Open repair can be performed with the use of antegrade inflow (from the supraceliac aorta) or retrograde inflow (from the iliac artery), with either a vein or prosthetic conduit to bypass one or more vessels, depending on the extent of disease. Hybrid procedures involving open access to the superior mesenteric artery and retrograde stenting, are also options.

Endovascular repair is a very successful, minimally invasive approach that provides initial relief of symptoms in up to 95% of patients and has a lower rate of serious complications than open repair ⁷⁷⁾. Despite these advantages, the use of endovascular techniques is associated with lower rates of long-term patency and a shorter time to the return of symptoms ⁷⁸⁾, ⁷⁹⁾, ⁸⁰⁾. Restenosis occurs in up to 40% of patients, and among these patients, 20 to 50% will require reintervention ⁸¹⁾, ⁸²⁾. Open repair is associated with slower recovery and longer hospital stays than endovascular repair. Data on mortality are inconsistent; however, patients treated with open repair have improved rates of symptom relief at 5 years and of primary patency (both rates are as high as 92%) and lower rates of reintervention  ⁸³⁾, ⁸⁴⁾, ⁸⁵⁾, ⁸⁶⁾.

Mesenteric venous thrombosis treatment

If your intestine shows no signs of damage and unless systemic anticoagulation is contraindicated, you’ll likely need to take anticoagulant medication for about 3 to 6 months. Anticoagulants help prevent clots from forming. In most cases, anticoagulation is the only therapy necessary; rates of recurrence and death are lower among patients who receive anticoagulation than among those who do not ⁸⁷⁾. The condition of approximately 5% of patients who receive conservative treatment will deteriorate, and further intervention will be required ⁸⁸⁾. Options for intervention in patients in whom medical treatment alone is unsuccessful include transhepatic and percutaneous mechanical thrombectomy ⁸⁹⁾, thrombolysis ⁹⁰⁾ and open intraarterial thrombolysis ⁹¹⁾. The few studies of the outcomes of these interventions have shown technical success with low risks of complications and death, although outcomes may be affected by the selection of patients and the timing of the intervention ⁹²⁾.

You might need a procedure to remove the clot. If parts of your intestine show signs of damage, you might need surgery to remove the damaged section. If tests show you have a blood-clotting disorder, you may need to take anticoagulants for the rest of your life.

As in all cases of mesenteric ischemia, any evidence of peritonitis, stricture, or gastrointestinal bleeding should trigger an exploratory laparotomy to assess for the possibility of bowel necrosis and the need for a second-look operation.

Non-occlusive mesenteric ischemia (NOMI) treatment

The initial goal of treatment is to address hemodynamic instability. Additional treatment may include systemic anticoagulation and the use of vasodilators in patients who do not have bowel infarction. Catheter-directed infusion of vasodilatory and antispasmodic agents, most commonly papaverine hydrochloride, can be used ⁹³⁾. Patients should be monitored closely by means of serial abdominal examinations, and open surgical exploration should be performed if there is concern about the possibility of peritonitis.

If there is evidence of severe colonic ischemia, your health care provider may recommend antibiotics to treat or prevent infections. Treating any underlying medical condition, such as congestive heart failure or an irregular heartbeat, is also important.

You’ll likely need to stop medications that constrict your blood vessels, such as migraine drugs, hormone medications and some heart drugs. In most cases, colon ischemia heals on its own.

If your colon has been severely damaged, you may need surgery to remove the dead tissue. In some cases, you may need surgery to bypass a blockage in one of your intestinal arteries. If angiography is done to diagnose the problem, it may be possible to open up a narrowed artery with angioplasty.

Angioplasty involves using a balloon inflated at the end of a catheter to compress the fatty deposits and stretch the artery, making a wider path for the blood to flow. A spring-like metallic tube (stent) also may be placed in your artery to help keep it open. A blood clot may be removed or be treated with medication to dissolve the clot.

Follow-up care

The long-term care of patients with mesenteric ischemia is focused on managing coexisting conditions and risk factors. Therefore, smoking-cessation measures, blood-pressure control, and statin therapy are recommended. Lifelong preventive treatment with aspirin is recommended in all patients who undergo endovascular or open repair ⁹⁴⁾. Patients who undergo endovascular repair should also receive clopidogrel for 1 to 3 months after the procedure ⁹⁵⁾. Regardless of the type of repair performed, in patients with atrial fibrillation, mesenteric venous thrombosis, or inherited or acquired thrombophilia, oral anticoagulant therapy is indicated and should be continued indefinitely or until the underlying cause of embolism or thrombosis has resolved ⁹⁶⁾.

Nutritional status and body weight should be monitored in all patients who have undergone an intervention for mesenteric ischemia. These patients may have prolonged ileus and food fear, and they may require total parenteral nutrition until full oral intake is possible ⁹⁷⁾. In patients who require bowel resection, diarrhea and malabsorption may occur. Extensive nutritional support, lifelong total parenteral nutrition, or even evaluation for small-bowel transplantation may be required in patients with persistent short-gut syndrome.

Because the recurrence of symptoms is common in patients with a history of mesenteric ischemia, lifelong repeated assessment of vascular patency is indicated ⁹⁸⁾. Duplex ultrasonography should be performed every 6 months for the first year after repair, then yearly thereafter ⁹⁹⁾. All patients should be informed about the risks and warning signs of stenosis, occlusion, and repeated episodes of ischemia. Any recurrence of symptoms should prompt diagnostic imaging. Given the high morbidity and mortality associated with acute mesenteric ischemia, preemptive revascularization is advised if evidence of recurrent stenosis or occlusion is identified ¹⁰⁰⁾.

Mesenteric ischemia prognosis

Even though survival of patients following mesenteric artery ischemia has improved over the past 3 decades, mesenteric ischemia still carries a very high morbidity and mortality. Mortality is estimated to be 60% to 80%, especially in those with more than a 24-hour delay in diagnosis. Early recognition of the problem can help reduce the mortality ¹⁰¹⁾, ¹⁰²⁾. If the doctor can make the diagnosis and begin treatment early, people usually recover well. People with acute mesenteric ischemia often do poorly because parts of the intestine may die before surgery can be done. This can be fatal. However, with prompt diagnosis and treatment, acute mesenteric ischemia can be treated successfully. Depending on the time of presentation and treatment, the mortality can approach 10-80%. Surgical intervention within 6 hours of symptom onset increases survival rates. If the diagnosis is not made or if treatment is not started until some of the affected intestine has died, 70 to 90% of people die. A person cannot survive if almost all the small intestine dies or is removed. Even those who survive are left with a risk of re-thrombosis, short bowel, a colostomy or ileostomy ¹⁰³⁾. Many patients are left with a short gut and require long-term parenteral nutrition. The outcomes are usually worse in the elderly, those with other comorbidities, sepsis and metabolic acidosis at the time of presentation.

The prognosis for chronic mesenteric ischemia is good after a successful surgery. However, it is important to make lifestyle changes to prevent hardening of the arteries from getting worse.

People with hardening of the arteries that supply the intestines often have the same problems in blood vessels that supply the heart, brain, kidneys, or legs.

The long-term mortality among patients with venous mesenteric ischemia is heavily influenced by the underlying cause of thrombosis; the rate of 30-day survival is 80%, and the rate of 5-year survival is 70% ¹⁰⁴⁾.

The outcomes in patients with nonocclusive mesenteric ischemia (NOMI) depend on the management of the underlying cause; overall mortality is 50 to 83% among these patients ¹⁰⁵⁾.