OVERVIEW
Superior mesenteric artery embolism is a disease caused by obstruction of the superior mesenteric artery due to the entry of emboli. The main trunk of the superior mesenteric artery has a large caliber, and the abdominal aorta is tilted at an angle, the embolus is easy to enter, so clinically this disease is more common, accounting for 40% to 50% of acute mesenteric vascular ischemia. Emboli generally come from the heart attached to the wall of the thrombus, so most commonly seen in rheumatic heart disease, coronary heart disease, infective endocarditis and recent infarction patients. In addition, emboli come from atherosclerotic plaques and occasionally bacterial emboli. These emboli are dislodged spontaneously or during catheterization.
Questions you may be concerned about
What does embolization of the superior mesenteric artery mean
Superior mesenteric artery embolism is a condition in which an embolus blocks the superior mesenteric artery, resulting in ischemia of the small intestine and part of the colon, causing symptoms such as abdominal pain.
The superior mesenteric artery starts from the abdominal aorta at about the height of the first lumbar vertebra and enters the root of the small intestine mesentery between the pancreas and duodenum, and the branches it gives off supply blood to the pancreas, duodenum, jejunum ileum, ascending colon, and right half of the transverse colon.
The embolus of superior mesenteric artery embolism is mostly originated from the heart or proximal large arteries, such as rheumatic heart disease of the redundant, the right and left auricles of the attached wall thrombus or large atherosclerotic plaques, abscess dislodgment of the embolus produced.
The superior mesenteric artery starts from the abdominal aorta at an acute angle, the lumen is wider, and the direction of blood flow is the same as that of the abdominal aorta, which makes it easy for the dislodged emboli to enter and block the narrower lumen or bifurcation, leading to embolism.
Superior mesenteric artery embolism often manifests severe abdominal pain, nausea, frequent vomiting, diarrhea, and in the late stage, vomiting dark red bloody fluid or bloody stools. Systemic symptoms include fever, tachypnea, decreased blood pressure, cyanosis, cyanosis of the fingertips, cold clammy skin, and dyspnea.
Patients with suspected superior mesenteric artery embolism are advised to seek prompt medical attention and early treatment to avoid adverse consequences.
Causes
The embolus of superior mesenteric artery embolism mainly originates from the heart, such as the wall embolus after myocardial infarction, the valve redundant organisms of subacute bacterial endocarditis, redundant organisms at rheumatic heart valve lesions and the shedding of wall thrombus of right and left auricles, etc; it can also originate from the wall thrombus of atherosclerosis of the large arteries or the shedding of atherosclerotic plaques, and embolus of the bacteria of abscess or septicemia.
The occurrence of mesenteric artery embolism is also related to the anatomical structure of the superior mesenteric artery, the superior mesenteric artery from the abdominal aorta is divided at an acute angle, and the aorta parallel to the aortic line, the lumen is thicker, and the direction of the abdominal aortic blood flow is the same, the dislodged embolus is easy to enter the vascular stenosis or bifurcation, resulting in vascular embolism.
Classification
Superior mesenteric artery embolism is generally categorized into acute superior mesenteric artery occlusion and chronic mesenteric vessel occlusion. Acute superior mesenteric artery occlusion is the most common cause of intestinal ischemia and is usually due to thrombosis and embolization. Most cases of chronic mesenteric vascular occlusion are characterized by atherosclerotic stenosis or obstruction of visceral vessels.
Symptoms
1. Acute superior mesenteric artery occlusion
(1) History of rheumatic heart disease, atrial fibrillation, endocarditis, myocardial infarction, valvular disease and valve replacement.
(2) Sudden severe abdominal colic, which cannot be relieved by drugs, early abdominal softness and non-distension, active bowel sounds, and inconsistency between symptoms and signs are the characteristics of early lesions.
(3) Continued development, the emergence of strangulated small bowel obstruction manifestations and signs, vomiting and diarrhea of bloody material.
(4) Early onset of shock.
2. Chronic mesenteric vascular occlusion
(1) Diffuse abdominal cramps after eating, may be accompanied by nausea and vomiting, the severity of which is related to the amount of food eaten, with progressive aggravation of symptoms.
(2) Chronic diarrhea, foamy stools, malabsorption, and weight loss.
Examination
1. Acute superior mesenteric artery occlusion
(1) Laboratory tests: markedly elevated white blood cell count of more than 20×109/L, hemoconcentration, metabolic acidosis.
(2) auxiliary examination ① X-ray abdominal plain film of the small intestine and colon moderate or mild insufflation and peritoneal fluid images. ② Selective arteriography can clarify the diagnosis. ③ Ultrasound Doppler examination and CT have auxiliary diagnostic significance.
2. Chronic mesenteric vascular occlusion
(1) Laboratory tests: Stool examination contains more lipids and a large amount of undigested food.
(2) Auxiliary examination Selective arteriography can show stenosis or even occlusion at the outlet of celiac artery and superior mesenteric artery, which is of diagnostic significance.
Diagnosis
1. The disease should be considered in people over 50 years old with a history of cardiac and vascular diseases who suddenly develop acute abdominal pain, vomiting, diarrhea and bloody stools.
2. Laboratory tests show markedly elevated white blood cell count, hemoconcentration and metabolic acidosis.
3. Abdominal X-ray radiography reveals small intestines, or abdominal puncture sees bloody material to help diagnosis. Abdominal X-ray radiographs show that the large and small intestines or colon are inflated or have a fluid level, and there is a generalized increase in density in the abdomen in the late stage due to the large amount of fluid in the intestinal and abdominal cavities.
4. Abdominal vascular multispectral ultrasound and enhanced CT are meaningful for diagnosis, and abdominal angiography is more meaningful for establishing diagnosis.
5. For patients with no obvious contraindications to colonoscopy, endoscopy can observe the scope, degree, and period of the lesion, which is also meaningful for confirming the diagnosis.
Differential diagnosis
1. Acute superior mesenteric artery occlusion
Acute superior mesenteric artery occlusion should be distinguished from strangulated small bowel obstruction caused by the progression of various mechanical intestinal obstruction. In addition, its clinical manifestations are similar to those of non-occlusive acute intestinal ischemia and should be distinguished. Selective arteriography is decisive for correct diagnosis.
2. Chronic mesenteric vascular occlusion
Chronic mesenteric vascular occlusion is characterized by intermittent abdominal pain, which is difficult to distinguish from other abdominal pain. Particular attention should be paid to the identification of chronic cholecystitis, chronic appendicitis, chronic pancreatitis. Angiography is essential to confirm the diagnosis of chronic mesenteric vascular occlusion.
Treatment
1. Acute superior mesenteric artery occlusion
(1) Non-surgical treatment ①Actively treat and control the primary disease. ②After arteriography, continuous arterial infusion of opium poppy, and try arterial thrombolysis with urokinase or thrombin.
(2) Surgical treatment ① embolism is located in a branch, involving localized necrosis of the intestinal tube, enterotomy and small bowel anastomosis. ② embolism is located in the main trunk of the superior mesenteric artery, all the small intestine and the right half of the colon is necrotic, then all the small intestine, the right half of the colon resection, postoperative parenteral nutritional support. If the embolism is located in the main trunk of the superior mesenteric artery and the bowel is not necrotic, then vein dissection should be performed to remove the embolus. If there is no blood or less blood outflow from the upper segment of the superior mesenteric artery after taking the embolus, autologous saphenous vein or artificial blood vessel should be performed in the abdominal aorta or the common skeletal artery and the superior mesenteric artery bypass anastomosis.
2. Chronic mesenteric vascular occlusion
(1) Non-surgical treatment: small amount and frequent meals, oral vitamin C, E and vasodilator drugs, low molecular dextrose drip, etc. (2) Surgical treatment: blood pressure, blood pressure, blood pressure, blood pressure, blood pressure, blood pressure.
(2) Surgical therapy ① thrombus endothelial stripping. ② Autologous vein bypass surgery over the narrow section. ③ Remove the stenotic segment of superior mesenteric artery and then reimplant the artery into the aorta. ④ Stenosis of the abdominal artery, autologous vein bypass surgery between the abdominal aorta and the splenic artery; or end-to-side anastomosis between the splenic artery and the abdominal aorta. ⑤ Stenosis at the outlet of the superior mesenteric artery, with autologous vein bypass surgery between the abdominal aorta below the opening of the middle colonic artery and below the level of the renal artery.