Clinical Characteristics And Endovascular Treatment Experience Of Spontaneous Isolated Superior Mesenteric Artery Dissection

BackgroundSpontaneous isolated dissection of the superior mesenteric artery(SISMAD)is a rare clinical vascular disease.The dissection is primary in the superior mesenteric artery(SMA)rather than caused by aortic dissection.With the development of medical imaging technology in recent years,more and more SISMADs have been diagnosed.The etiology and pathogenesis of SISMAD is not yet clear,but its high-risk factors,such as hypertension,arteritis,atherosclerosis,and smoking,have been recognized by scholars.The most common clinical manifestation of SISMAD is sudden abdominal pain.Other symptoms include nausea,vomiting,and diarrhea.The diagnosis depends on abdominal CT angiography(CTA).There are three main treatment methods:conservative treatment(fasting,gastrointestinal decompression,parenteral nutrition,control of blood pressure,etc.),endovascular repair and open surgery.In order to manage SISMAD patients better,and choose a reasonable treatment,scholars have classified the disease into several types according to the SISMAD CTA form,such as Sakamoto type,Yun classification,Zerbib type,but there is no unified conclusion.Because of its obvious effects,low risk,and rapid postoperative recovery,interventional surgery has gradually become the mainstream method for the treatment of SISMAD.However,there are many controversies in terms of surgical indications,surgical methods,etc.,especially in recent years,most scholars have reported conservative treatment cured some SISMAD patients.ObjectTo investigate the clinical features and endovascular treatment outcomes of spontaneous isolated superior mesenteric artery dissection(SISMAD).MethodsThe clinical data of 42 patients diagnosed as spontaneous solitary superior mesenteric artery dissection in Department of Vascular Surgery,Qilu Hospital of Shandong University from January 2008 to October 2017 were retrospectively analyzed.Among them,38 were males and 4 were females.Age between 35 and 69 years old,and the average age is about(50.2±6.6)years old.There were 39 cases with symptoms and 3 cases without obvious symptoms.Asymptomatic 3 patients and 1 symptomatic patient received conservative treatment.The main measures included fasting,gastrointestinal decompression,parenteral nutrition,and control of blood pressure.One patient underwent open surgery for intestinal necrosis and endovascular repair after surgery.One case was diagnosed as acute SMA embolization and received open thrombectomy,and SISMAD had been formed after surgery,and then endovascular repair was used to cure the dissection.The remaining 36 patients received one-stage endovascular treatment.Prior to endovascular repair,all cases were confirmed by CTA,and were classified according to the method of our center:type ?,mainly SISMAD stenosis or thrombosis of the true lumen;type ?,SISMAD false lumen expansion to form dissection aneurysm;type ?,SISMAD true lumen stenosis with false lumen expansion at the same time.According to the above classification,a reasonable choice of the appropriate treatment,including balloon angioplasty,catheter thrombolysis,stent implantation,stents and coil embolization.There are three major surgical approaches,transfemoral access,transradial or brachial access,combined transfemoral and radial or branchial access.Surgical approach selection mainly refers to the angle between the abdominal aorta and the superior mesenteric artery(?)and is classified according to the following types:type ? 0>90°;type ? 45°<??90°;type ???45°.All patients received regular antiplatelet therapy to prevent complications such as stent thrombosis and stent restenosis.All patients were followed up for a postoperative period.The follow-up included symptom improvement,mesenteric vascular CTA,and vascular morphology.ResultsOf 42 patients diagnosed with SISMAD,38 were male(90.5%),4 females(9.5%),aged(35-69)years old,and average age was(50.2±6.6)years old.Among them,20(47.6%)had hypertension;4(9.5%)had type 2 diabetes;20(47.6%)had hyperlipidemia;17(40.5%)had homocysteine(Hey)increased;6 cases(14.3%)with coronary heart disease;21 cases(50%)of previous long-term smoking history.There were 39 patients with clinical symptoms,mainly abdominal pain(92.9%),and 1 patient(2.4%)also had nausea,vomiting and blood in the stool.Three patients(7.1%)had no obvious symptoms due to physical examination.According to Zerbib classification method,2 cases(4.8%)were type ?,15 cases(35.7%)were type ?,5 cases(11.9%)were type ?,1 case(2.4%)was type?,9 cases(21.4%)were type ?,10 cases(23.8%)were type ?.But according to our center classification method,12 cases(28.6%)were type ?,9 cases(21.4%)were type ?,and 21 cases(50%)were type ?.According to the angle between the abdominal aorta and the superior mesenteric artery(0),5 cases(11.9%)were type ?,31 cases(73.8%)were type ?,6 cases(14.3%)were type ?.In terms of treatment options,conservative treatment and regular follow-up were performed in 3 cases without obvious symptoms and 1 case of abdominal pain.One case was received open surgery because of intestinal necrosis,and SISMAD endovascular repair was performed for the second postoperative period.One patient was diagnosed as SMA acute embolism and accepted open SMA thrombectomy.After surgery,SISMAD was formed,and underwent endovascular repair.The remaining 36 patients underwent endovascular repair in one session.However,because the guidewire could not be selected into the true lumen,one patient failed in interventional surgery.The choice of endovascular repair was mainly based on the preoperative CTA morphology and our central classification method:15 cases with stent graft implantation(5 cases of type ?,6 cases of type ?,4 cases of type ?).Twenty patients were implanted with self-expanding bare stent.(6 in type ?,2 in type ?,12 in type ?,1 in type ?,and 3 in type ? received double bare stent implantation).There was 1 case of type ? with SMA received catheter thrombolysis at the same time.Another type ? with dissection artery aneurysm accepted coil embolization.Of the 35 patients who successfully performed one-stage endovascular treatment,15 were treated with a femoral approach,9 with a radial or branchial approach,and 11 with both femoral and radial or branchial approach.According to the classification of the angle between the abdominal aorta and the superior mesenteric artery(0),5 cases of type ? were successfully performed via the femoral approach.In 24 cases of Type ?,12 cases were successfully treated with radial or branchial artery approach(100%);10 cases were successful(83.3%)in 12 cases undergone femoral approach,and 2 cases failed to transfer into radial approach.The success rate of the two surgical approaches was compared,P=0.239.All 6 cases of type ? were treated with transradial or branchial arteries,and all were successful(100%).In the follow-up results,2 cases of asymptomatic SISMAD showed no-progress,and 1 case progressed to dissection aneurysm and finally received endovascular repair.One symptomatic SISMAD patient who received conservative treatment experienced clinical symptoms such as recurrent abdominal pain.The symptoms eventually improved and the CTA showed dissection.One patient who had developed intestinal necrosis and had undergone two-stage endovascular treatment died due to intestinal necrosis.One patient who underwent open surgical treatment for SMA embolization developed SISMAD and received endovascular treatment.One patient with failure of endovascular treatment experienced recurrent abdominal pain during follow-up.The remaining 35 patients who successfully received one-stage endovascular treatment all had their symptoms disappeared.There were 2 cases of stent distal stenosis,1 case of stent stenosis,and no intestinal ischemia or stent occlusion.ConclusionSISMAD is a rare clinical disease whose main clinical manifestation is abdominal pain.Smoking and high Hcy are the risk factors for SISMAD to be equivalent to hypertension and hyperlipidemia.The diagnosis is dependent on abdominal CTA,and the classification of SISMAD based on imaging findings is conducive to guiding clinical treatment.According to our center classification method can effectively guide the choice of endovascular treatment.Endovascular interventional therapy is a safe and effective method for treating symptomatic SISMAD.