a 48-year - old woman suddenly experienced a diffuse rending abdominal pain , and so she visited the hospital .
emergency contrast - enhanced abdominal ct revealed the presence of mural thrombus within the main trunk of the sma without any evidence of abdominal aortic aneurysm or dissection ( fig .
1a ) . there was no finding of bowel ischemia such as bowel wall thickening or abnormal contrast enhancement .
her medical history included hypertension , which had been controlled with a single drug for 4 years .
the physical examination revealed a temperature of 36.8 , blood pressure 110/70 mmhg , and the pulse was 68 beats per minute and regular .
an electrocardiogram , chest radiograph , and abdominal plain films were also normal . under the impression of thromboembolic occlusion of the sma
the superior mesenteric arteriogram demonstrated the complete occlusion of the ileocolic and right colic branches of the sma ( fig .
an inferior mesenteric arteriogram showed collateral flow through a marginal artery to the occluded branches .
a 5-f 11-cm multisidehole infusion catheter ( cook , bloomington , in , u.s.a . ) was placed within the main trunk of the sma and then urokinase was infused at a rate of 100,000 iu per hour .
after 14-hours of infusion of urokinase , she still suffered from the symptoms , and the follow - up arteriogram revealed an isolated dissection of the sma ( fig .
we considered percutaneous stent placement instead of surgical bypass graft . over the guidewire ( terumo , tokyo , japan ) via a right femoral artery approach , an 870-mm self - expandable wallstent ( boston scientific , watertown , ma , u.s.a . ) was placed in the true lumen so that the proximal end was dipped into the aortic lumen ( fig .
we used a relatively long stent because of the stability of this stent within the sma .
the control angiogram showed a patent , true lumen with good blood flow in all the branches of the sma .
the patient complained of postprandial abdominal pain for a week , however , the symptom was gradually subsided and the patient was discharged two weeks after the stent placement .
two months later , ct angiograms showed good blood flow through the fully expanded stent and all the branches of the sma .
however , the stent was shortened and the proximal segment of the sma was narrowed by 50 - 75% ( fig .
1e ) , but the patient did n't complain of any symptoms for 6 months after the stent placement .
a 54-year - old healthy man experienced severe epigastric pain just after drinking a cup of cold water , and so he visited to our emergency room .
abdominal ct showed the common trunk of celiac and superior mesenteric arteries without evidence of bowel necrosis .
an intimal flap was noted 1.5 cm distal to the orifice of the common trunk with a distally thrombosed and proximally patent false lumen ( figs .
a celiacomesenteric arteriogram demonstrated a severely narrowed true lumen and an aneurysmally dilated false lumen ( fig . 2c ) .
an 860-mm self - expandable wallstent was placed in the true lumen to cover the dissection so that the proximal end of the stent was at the orifice of the sma .
the control angiogram showed a patent true lumen with good blood flow in all the branches of the sma ( fig .
afterwards , his symptom was disappeared and he was discharged a week after the stent placement .
four months later , his celiacomeseteric arteriogram showed good blood flow through the stent , however , the aneurysmally dilated false lumen had recurred ( fig .
to prevent the progression of the arterial dissection , another 1050-mm self - expandable stent ( s.m.a.r.t . , cordis , miami , fl , u.s.a . ) was placed within the wallstent to cover the opening of the intimal flap ( fig .
three days later , a ct angiogram showed good patency through the fully expanded stents .
the extent of the false lumen was significantly decreased and the tip of the latter stent was at the orifice of the celiacomesenteric trunk .
a 48-year - old woman suddenly experienced a diffuse rending abdominal pain , and so she visited the hospital .
emergency contrast - enhanced abdominal ct revealed the presence of mural thrombus within the main trunk of the sma without any evidence of abdominal aortic aneurysm or dissection ( fig .
1a ) . there was no finding of bowel ischemia such as bowel wall thickening or abnormal contrast enhancement .
her medical history included hypertension , which had been controlled with a single drug for 4 years .
the physical examination revealed a temperature of 36.8 , blood pressure 110/70 mmhg , and the pulse was 68 beats per minute and regular .
an electrocardiogram , chest radiograph , and abdominal plain films were also normal . under the impression of thromboembolic occlusion of the sma
the superior mesenteric arteriogram demonstrated the complete occlusion of the ileocolic and right colic branches of the sma ( fig .
an inferior mesenteric arteriogram showed collateral flow through a marginal artery to the occluded branches .
a 5-f 11-cm multisidehole infusion catheter ( cook , bloomington , in , u.s.a . ) was placed within the main trunk of the sma and then urokinase was infused at a rate of 100,000 iu per hour .
after 14-hours of infusion of urokinase , she still suffered from the symptoms , and the follow - up arteriogram revealed an isolated dissection of the sma ( fig .
we considered percutaneous stent placement instead of surgical bypass graft . over the guidewire ( terumo , tokyo , japan ) via a right femoral artery approach , an 870-mm self - expandable wallstent ( boston scientific , watertown , ma , u.s.a . ) was placed in the true lumen so that the proximal end was dipped into the aortic lumen ( fig .
we used a relatively long stent because of the stability of this stent within the sma .
the control angiogram showed a patent , true lumen with good blood flow in all the branches of the sma .
the patient complained of postprandial abdominal pain for a week , however , the symptom was gradually subsided and the patient was discharged two weeks after the stent placement .
two months later , ct angiograms showed good blood flow through the fully expanded stent and all the branches of the sma .
however , the stent was shortened and the proximal segment of the sma was narrowed by 50 - 75% ( fig .
1e ) , but the patient did n't complain of any symptoms for 6 months after the stent placement .
a 54-year - old healthy man experienced severe epigastric pain just after drinking a cup of cold water , and so he visited to our emergency room . his physical examination and routine lab values were negative . an electrocardiogram , chest radiograph and abdominal plain films were also normal .
abdominal ct showed the common trunk of celiac and superior mesenteric arteries without evidence of bowel necrosis .
an intimal flap was noted 1.5 cm distal to the orifice of the common trunk with a distally thrombosed and proximally patent false lumen ( figs .
a celiacomesenteric arteriogram demonstrated a severely narrowed true lumen and an aneurysmally dilated false lumen ( fig . 2c ) .
an 860-mm self - expandable wallstent was placed in the true lumen to cover the dissection so that the proximal end of the stent was at the orifice of the sma .
the control angiogram showed a patent true lumen with good blood flow in all the branches of the sma ( fig .
afterwards , his symptom was disappeared and he was discharged a week after the stent placement .
four months later , his celiacomeseteric arteriogram showed good blood flow through the stent , however , the aneurysmally dilated false lumen had recurred ( fig .
to prevent the progression of the arterial dissection , another 1050-mm self - expandable stent ( s.m.a.r.t . , cordis , miami , fl , u.s.a . ) was placed within the wallstent to cover the opening of the intimal flap ( fig .
three days later , a ct angiogram showed good patency through the fully expanded stents .
the extent of the false lumen was significantly decreased and the tip of the latter stent was at the orifice of the celiacomesenteric trunk .
the superior mesenteric artery is the second most frequent peripheral artery after the internal carotid artery to be affected by spontaneous dissection ( 2 , 3 ) . in the medical literature ,
the patients were predominantly male and over forty years of age ( 1 , 2 , 4 ) .
the reported risk factors of this disease were hypertension , cystic medial necrosis , abdominal aortic aneurysm and so on ; however , most of the patients were generally healthy without underlying disease ( 5 , 6 ) .
when diagnosing sma dissection , a contrast - enhanced ct scan can reveal the presence of an intimal flap and mural thrombus within the sma lumen ( 3 ) .
however , because the intimal flap can not be always noticed , the mural thrombus may be only the clue of the sma dissection . in our former case
, we misdiagnose the dissection as the thromboembolic occlusion of the sma and then we preformed an unnecessary pharmacologic thrombolysis .
therefore , the arterial dissection must be included as one of differential diagnosis in cases of mural thrombosis of the sma . the mainstay of treatment of the spontaneous dissection of the sma has been surgery ( 1 , 2 ) .
surgical techniques have included graft interposition , reimplantation of sma on the aorta , intimectomy , right gastroepiploic artery bypass , and simple arteriotomy with thrombectomy ( 1 ) .
successful conservative management has been reported , although long - term results have not been obtained ( 2 , 4 ) .
several authors have shown promising results for the stenting of chronic lesions of the visceral arteries ( 7 , 8) .
( 2 ) have reported the first successful case of isolated spontaneous dissection of the sma treated by percutaneous stent placement .
the patient did n't experiencea recurrence of abdominal angina during a 6-month follow - up period .
however , in acute mesenteric ischemia due to arterial dissection , the clinical outcome and complications after the stent placement can not be anticipated yet because of an insufficient number of patients . in our cases ,
the wallstent showed one important disadvantage , and that is proximal shortening . for our female patient ,
the mechanism is not certain , however , suspected mechanisms may be the proximal shortening of the non - fixed wide proximal sma segment and an irritation of the vessel wall by the free end of the stent . for our male patient ,
the opening of the false lumen was n't covered by the stent due to proximal shortening , so that the aneurysmally dilated false lumen compressed the stent .
reported that the dissection usually begins 1.5 - 3 cm from the orifice of the sma , thereby sparing the origin of the artery .
this segment of the sma corresponds with the portion running behind the pancreas , and being a fixed site , it may bear the consequences of a straining force ( 1 ) .
therefore , this proximal sma segment must be securely covered by the stent . in our latter patient , an additional stent with less shortening and a greater ability to conform
consequently , the stent for the sma dissection needs several important characteristics ; minimal shortening , good conformability and flexibility , and it must not change location due to the continuous movement of the mesentery . as in aortic dissection ,
most of cases of segmental dissection without side branch involvement or distal reentry may benefit from implanting a covered stent graft over the entry site of the dissection , thus causing thrombosis and obliteration of the false lumen ( 9 ) .
multidetector row ct facilitates shorter acquisition times , retrospective creation of thinner sections from the raw data , and improved three - dimensional rendering with diminished helical artifacts ( 10 ) . in our cases , the three - dimensional ct angiography provided sufficient information for the assessment of the spontaneous dissection of the sma .
these techniques were also useful for our follow - up examination after the stenting . concerning conventional arteriography , catheterization into the dissected peripheral artery at an early stage
, the conventional diagnostic angiography will soon be replaced with ct angiography . in conclusion ,
percutaneous stent placement is a safe and feasible therapeutic alternative for the treatment of isolated spontaneous dissection of the sma .
however , studies with a larger group of patients and long - term follow - up will be needed to validate this procedure .
 isolated spontaneous dissection of the superior mesenteric artery ( sma ) is a rare cause of acute mesenteric ischemia . 
 two patients were successfully treated by percutaneous stent placement within the main trunk of the sma . 
 emphasis is placed on the feasibility of nonsurgical management with percutaneous stent placement of isolated spontaneous dissection of the sma . 
CASE REPORT
Case 1
Case 2
DISCUSSION