Abdominal Aortic Branch Occlusion
- The branches of the aorta can become obstructed due to several conditions such as atherosclerosis, the atypical proliferation of muscle cells within the arterial walls (known as fibromuscular dysplasia), blood clots, or various other diseases.
- This obstruction leads to symptoms associated with insufficient blood supply, including pain, in the region supplied by the affected artery.
- Diagnostic procedures typically involve various imaging techniques.
- The treatment approach may include the elimination of a blood clot, angioplasty (a procedure to widen narrowed or obstructed arteries or veins), or in certain cases, surgical creation of a bypass using grafts.
The aorta, the body’s main artery, carries oxygenated blood from the heart and distributes it throughout the body through its many smaller branches. The part of the aorta that runs through the abdomen is known as the abdominal aorta. This section of the aorta gives rise to several important branches that supply blood to different parts of the body, including:
- The intestines, served by the celiac artery and the superior and inferior mesenteric arteries
- The kidneys, through the renal arteries
- The legs, via the iliac arteries
Obstructions in the aorta’s arterial branches can happen suddenly or develop over time.
Acute occlusion, or sudden blockage, in the branches of the abdominal aorta can occur due to various reasons. One common cause is a blood clot forming within the artery. Alternatively, an embolism, where a clot travels to the artery from another location, can also lead to acute occlusion. Additionally, arterial dissection, characterized by the sudden separation of the artery wall layers, is another possible cause.
On the other hand, gradual blockages typically stem from atherosclerosis, a condition where cholesterol and other fatty substances accumulate within the arterial walls. Moreover, fibromuscular dysplasia, which involves abnormal muscle growth in the arterial wall, or external pressure from an enlarging abdominal tumor, can also contribute to the development of blockages.
Furthermore, these blockages can affect arteries in the legs and, less frequently, in the arms. This manifestation is known as Occlusive Peripheral Arterial Disease, highlighting its impact on peripheral circulation.
Symptoms of Abdominal Aortic Branch Occlusion
A sudden arterial blockage stops blood flow instantly, causing severe pain in the abdomen, back, or legs, depending on the blocked artery. Without quick blood flow restoration, organ failure and tissue death (necrosis) can happen within hours.
Symptoms from gradual blockages change based on the affected artery and blockage extent. The growth rate of the blockage and the body’s alternative blood route development affect symptom severity.
A sudden lower aorta blockage at the common iliac arteries usually causes immediate, painful, pale, and cold legs. Leg pulses become undetectable, and numbness may occur. If the blockage is in an iliac artery, it affects only one leg. These are medical emergencies due to their severe impact on blood flow.
Gradual narrowing of the lower aorta or common iliac arteries typically leads to cramping and walking pain (intermittent claudication) in the buttocks and thighs. Legs might feel cold or appear pale. Chronic blockage can cause erectile dysfunction, known as Leriche syndrome.
A sudden, complete renal artery blockage, supplying the kidneys, can cause side pain and blood in the urine, needing urgent care.
Gradual and moderate renal artery narrowing often shows no symptoms. But severe narrowing can lead to kidney failure and high blood pressure, a challenging condition known as renovascular hypertension.
A sudden, complete superior mesenteric artery blockage, supplying the intestine, leads to severe abdominal pain, nausea, and vomiting. This is a medical emergency. People may feel urgent bowel movement needs and become seriously ill.
On examination, the abdomen might be tender, with pronounced, vague abdominal pain. Bowel sounds may reduce to silence. Initially, the stool may have little blood, but it can quickly worsen. This blockage can lower blood pressure and cause shock as the intestine suffers necrosis or gangrene.
Gradual constriction of the superior mesenteric artery causes intense navel-centered pain about 30 to 60 minutes after eating. This leads to eating fear and significant weight loss due to impaired nutrient absorption. People may also have nausea, vomiting, constipation, or diarrhea.
Hepatic or splenic artery blockages are less severe but can damage the liver or spleen. Hepatic artery blockage may show no symptoms or cause abdominal pain, fevers, chills, nausea, vomiting, and jaundice. Splenic artery blockage might cause no symptoms or abdominal pain with fevers and chills. Symptoms vary with the blockage extent and the body’s alternative blood flow capacity.
Diagnosis of Abdominal Aortic Branch Occlusion
Imaging tests are crucial in diagnosing arterial blockages. Initially, doctors evaluate symptoms and perform a physical examination. Following this, they often turn to imaging tests like ultrasonography, CT angiography, MRA, or traditional angiography for a more definitive diagnosis.
Specifically, angiography, which is more invasive, entails the insertion of a catheter into a thigh artery. This method is particularly used when planning surgery or angioplasty. It not only provides detailed artery images but also involves injecting a contrast agent that highlights the artery’s diameter on X-rays. Significantly, this technique is usually more accurate than ultrasonography in detecting certain types of blockages.
Furthermore, many medical centers are now opting for less invasive techniques such as CT angiography or MRA. Unlike traditional angiography, these methods do not require inserting a catheter into a major artery. Instead, they involve the injection of a small amount of contrast agent into the bloodstream via an intravenous catheter in the arm, simplifying the process and reducing patient discomfort.
Treatment of Abdominal Aortic Branch Occlusion
Acute occlusion of blood vessels demands urgent medical action to restore blood flow. This can include procedures like embolectomy (blood clot removal), angioplasty, clot-dissolving medication, or sometimes, emergency surgical bypass.
In sudden blockages of the lower aorta and common iliac arteries, immediate surgery is critical. Doctors can use a catheter to remove the clot or perform open surgery to extract it. This quick action is vital to prevent severe complications and protect the affected tissue.
For sudden renal artery blockages, doctors often use angioplasty with clot removal, stent insertion, or surgery. Done quickly, these can restore blood flow and save kidney function.
Angioplasty involves a balloon-tipped catheter to clear the blockage. Doctors may also use stents, especially drug-eluting types, to keep the vessel open. In chronic blockage cases, surgery or angioplasty with antiplatelet medications might be necessary.
Gradual, moderate renal artery blockages may not need treatment if blood pressure and kidney function are stable. For renovascular hypertension, doctors often prescribe a mix of antihypertensives, including ACE inhibitors, which need careful kidney monitoring. In severe cases, angioplasty or bypass surgery may be options.
Rapid interventions are essential for sudden blockages in the superior mesenteric artery. These include angioplasty, stent placement, bypass surgery, or specific medications. Doctors may go straight to surgery, sometimes removing or bypassing the blockage or even the affected intestine segment.
During angiography, clot-dissolving drugs or vasodilators can clear blockages, potentially avoiding surgery. Quick restoration of blood flow is crucial for successful treatment.
For gradual narrowing of the superior mesenteric artery, medications like nitroglycerin can ease pain, but angioplasty or surgery might be needed to widen the artery effectively.
In hepatic or splenic artery blockages, surgical intervention is usually required to clear the obstruction and restore blood flow to the liver and spleen. The surgical approach depends on the blockage’s location, extent, and the patient’s health.