Keywords
abdomen - arteries - vascular - angiography - CT-angiography - stents
Introduction
Isolated dissection of the superior mesenteric artery (IDSMA) is an increasingly frequently
diagnosed pathology [1]. This is partly due to the availability of computed tomography (CT) scanners, which
allow rapid and accurate detection of the dissected superior mesenteric artery (SMA)
[1]. In this context, IDSMA is symptomatic in 86 % of cases [1] and accounts for 0.03 % of patients presenting with abdominal pain in an emergency
department [2]. Causes of pain symptomatology include bowel ischemia and irritation of periarterial
nerve plexuses combined with symptoms like nausea and vomiting [3]
[4]. Mechanical stress has been discussed as an initiating cause for IDSMA. In vitro,
dissection has been shown to originate mainly from the anterior wall of the convex
curvature, or from the inferior end of the pancreas, where the fixed part of the artery
runs into a more mobile part [5]
[6]. Another factor is an angle between the SMA and the distal aorta of more than 70
degrees that may lead to unfavorable hemodynamics [7]. However, a definite cause has not yet been found. Male gender, hypertension, and
smoking have been identified as major risk factors. Diabetes mellitus, hyperlipidemia,
and cardiac disease may also be associated with IDSMA but appear to be less relevant
[8]. In the acute setting, computed tomography angiography (CTA) with imaging of visceral
vessels in an arterial contrast phase is the gold standard [9]. Laboratory values and conventional radiographs of the abdomen are rarely conclusive
[10]. In the absence of adequate collateral flow, IDSMA poses a risk to ischemia of the
intestine leading to bowel wall infarction and peritonitis. In addition, rupture of
the dissected SMA may result in pseudoaneurysm formation. The reported mortality rate
is approximately 0.5 % [8].
Various treatment strategies have been discussed in the literature, including conservative
medical, endovascular, and surgical therapy [1].
Due to the rarity of the disease, the scarcity of available data, and the complexity
of this condition, there are still uncertainties with special regard to appropriate
management. Existing data are mostly limited to case reports and small case series.
To address the need for better evidence, we present our single center data on the
management of IDSMA collected over a period of five years.
Methods and Patients
Patient records were drawn from the electronic medical record database covering a
period of five years. Search terms included mesenteric artery dissection, but only
patients who had an isolated dissection of the SMA were considered. Dissections based
on other entities, i. e., aortic dissection with mesenteric malperfusion, were not
included in our study. Imaging data were acquired from the PACS of our institution
(picture archiving and communication system, MERLIN Diagnostic Workcenter, version
5.8.1.200625; Phönix-PACS GmbH, Freiburg im Breisgau, Germany). All patients were
examined and treated as part of routine care. Informed consent was obtained from all
patients before endovascular and surgical treatment. Study design and data acquisition
complied with the institutional review board guidelines regarding anonymized retrospective
studies.
Study cohort
In total, six patients were identified. All patients were male (6/6) and predominantly
smokers (4/6) with a mean age of 52 years (range, 45–58). The majority of patients
were symptomatic, with four of six patients (66.7 %) experiencing severe abdominal
pain. In total, three of six patients (50 %) were treated conservatively, one of six
patients (16.7 %) by a surgical intervention, and two of six patients (33.3 %) by
endovascular therapy. Of those cases treated conservatively, two patients were asymptomatic
and one patient was symptomatic.
Patient demographics and characteristics are presented in [Table 1].
Table 1
Case specifications. RAS: Renal artery stenosis; VAS: Visual Analogue Scale: 0–10
with 10 the most pain; CV: cardiovascular; CT: computed tomography; US: Ultrasound.
Case
|
1
|
2
|
3
|
4
|
5
|
6
|
|
Gender
|
m
|
m
|
m
|
m
|
m
|
m
|
100 %
|
Age
|
54
|
56
|
53
|
58
|
46
|
45
|
Mean: 52
|
Submission for
[1]
|
Tumor follow-up
|
RAS
|
Pain
|
Pain
|
Pain
|
Pain
|
Pain: 67 %
|
Pain specification
|
|
|
|
|
|
|
|
|
0
|
0
|
8
|
6
|
7
|
6
|
Mean: 4.5
|
|
None
|
None
|
Lower abd left
|
Epigastric
|
Epigastric
|
Epigastric
|
|
CV risk factors:
|
|
|
|
|
|
|
|
|
No
|
Yes
|
Yes
|
Yes
|
No
|
Yes
|
67 %
|
|
No
|
Yes
|
Yes
|
Yes
|
No
|
No
|
50 %
|
|
No
|
No
|
No
|
Yes
|
No
|
No
|
17 %
|
|
No
|
No
|
No
|
Yes
|
No
|
No
|
17 %
|
|
No
|
No
|
No
|
Yes
|
No
|
No
|
17 %
|
|
No
|
No
|
No
|
Yes
|
No
|
No
|
17 %
|
|
No
|
No
|
No
|
Yes
|
No
|
No
|
17 %
|
Hypercholesterolemia
|
No
|
No
|
No
|
Yes
|
No
|
No
|
17 %
|
Dissection:
|
|
|
|
|
|
|
|
|
I
|
IIb
|
IIb->IIa[3]
|
IIb
|
IIb
|
IIa
|
|
|
67
|
57
|
38
|
55
|
69
|
28
|
|
Treatment
|
|
|
|
|
|
|
|
|
No
|
No
|
Yes
|
No
|
No
|
No
|
|
|
No
|
No
|
No
|
Yes
|
No
|
No
|
|
|
No
|
No
|
No
|
No
|
Yes
|
No
|
|
|
No
|
No
|
No
|
No
|
No
|
Yes
|
|
Follow-up
|
|
|
|
|
|
|
|
|
CT
|
CT/US
|
CT/US
|
Lost
|
CT
|
CT
|
|
|
19
|
226
|
23
|
Lost
|
58
|
14
|
Mean: 68
|
|
No
|
Yes
|
No
|
No
|
No
|
No
|
|
Further treatment
[5]
|
No
|
No
|
No
|
No
|
No
|
No
|
|
1 at initial presentation at the hospital
2 according to Yun et al.
3 change of type after 6 months
4 in millimeter
5 during follow-up period
Diagnostic investigations
The initial diagnostic approach used to identify IDSMA was contrast-enhanced, multislice
CTA in five of six patients (83.3 %), and one patient (16.7 %) was examined with CTA
and magnetic resonance angiography (MRA). The IDSMA was clearly depicted in all cases
(6/6).
Radiologic reading contained descriptions of the entry/re-entry of the false lumen,
the dissection length, the degree of stenosis of the patent lumen, and the involvement
of side branches of the SMA. Moreover, attention was also paid to collateralization
via the celiac trunk (CA).
Follow-up investigations were performed by CTA and ultrasound [US].
IDSMA was classified according to Yun et al. [5]: type I describes a patent true and false lumen with the false lumen showing re-entry.
In contrast, type II does not present with re-entry (further subtyping: type IIa:
the false lumen is patent, type IIb: the false lumen is thrombosed). In type III,
both lumina are thrombosed. Symptomatic patients usually present with type II and
III dissections.
Outcome measures
The primary outcome measure of our study was complete absence of IDSMA-related symptoms
(i. e., abdominal pain, nausea, vomiting) after conservative, endovascular, or surgical
treatment during the follow-up period. Symptoms were investigated by physicians of
the department of surgery. The secondary outcome measure was worsening of imaging
findings such as increasing length of the stenosis, dilatation, or worsening of true
lumen compromise as determined by a radiologist.
Follow-up
After the diagnosis of IDSMA, all patients were closely monitored, regardless of treatment.
Clinical examination was performed in the outpatient clinic of the surgical department
for routine follow-up. All patients were advised to immediately contact the outpatient
clinic at the onset of new or worsening symptoms. One patient was lost to follow-up. The
mean follow-up time for the remaining five patients was 68 months (range: 14–226 months).
Literature review
A literature search of articles on IDSMA published between May 21, 2009 and November
8, 2022 was performed using PubMed for relevant articles published in English. The
search terms included “mesenteric artery dissection”. Retrieved results were filtered
using information provided in the title and abstract. Studies addressing topics other
than isolated dissection of the SMA were excluded. Results were also excluded when
a full text was not available (i. e., abstract only or congress contributions). Studies
covering other mesenteric vessels than the SMA, experimental or in-vitro studies,
and systematic reviews were also excluded.
Results
Dissection specifications
The overall dissection length was 52 mm ± 16 mm (48 ± 18 mm in symptomatic and 62 mm
± 7 in asymptomatic patients).
The two asymptomatic patients in our cohort were classified as type I and II, respectively.
The four symptomatic patients were classified as type II. One of those symptomatic
patients showed a change of type from IIb to IIa with recanalization of the false
lumen in a CTA follow-up one month after the acute event ([Fig. 1]). In this patient, additional recanalization of the true lumen occurred after approximately
6 months with further improvement of perfusion on imaging.
Fig. 1 (case 3): Patient with symptomatic isolated dissection of the superior mesenteric
artery (IDSMA). Computed tomography (CT) scans in axial (a, b) and sagittal (c, d) orientation and arterial contrast phase. The patient initially presented with dissection
type IIb (a, c). After receiving oral medications, a 6-month follow-up examination
revealed recanalization of the collapsed or stenosed true lumen and also recanalization
of the false lumen, resulting in a change of classification from type IIb to type
IIa (c and d) at 0 and 6 months.
Treatment strategy
At our institution, all treatment decisions were made by multidisciplinary consensus
owing to the rarity of the disease, the complex anatomy, and the individual circumstances
in each patient.
The asymptomatic patients did not require endovascular or surgical treatment. Instead,
their conservative treatment consisted of a watch-and-wait strategy as well as antihypertensive
medications. In one symptomatic patient, a conservative therapy regimen was chosen,
consisting of full anticoagulation (heparin, 60 mg per day for 6 weeks), single antiplatelet
therapy (acetylsalicylic acid) and antihypertensive medication (ramipril) for lifetime
as well as analgesics (novaminsulfone/paracetamol), and an antiemetic (metoclopramide).
In one case, a surgical approach was selected with patch angioplasty of the central
SMA with bovine pericardium.
Two endovascular procedures were performed in our local angiography suite equipped
with state-of-the-art flat-panel detector angiographic systems (Axiom Artis, Siemens
AG, Healthcare Sector, Forchheim, Germany; Azurion 7 C20, Philips Healthcare, Best,
The Netherlands). The procedures were carried out under local anesthesia via a retrograde
femoral artery approach.
In one of those cases ([Fig. 2]), the SMA was cannulated with a selective catheter (cobra-1 configuration) through
a 7F sheath. DSA revealed dissection of the SMA with formation of two pseudoaneurysms
directly proximal to the jejunal arcade region, both arising from the true lumen.
During the session, there was a detailed interdisciplinary discussion and consensus
concerning the findings and the treatment strategy between surgeons and interventional
radiologists. For the treatment of the distal segment of the SMA including the more
distal pseudoaneurysm, two balloon-expandable bare metal stents (BMS) (Tsunami 6/18 mm,
Terumo, Tokyo, Japan; RX Herculink Elite 6/18 mm, Abbott, Redwood City, CA) and four
microcoils (VortX 3/2,5, Boston Scientific, Natick, MA) were used. Next, a balloon-expandable
covered stent (Advanta V12 7/22 mm, Atrium Medical Corporation, Merrimack, NH) was
inserted into the region of the proximal pseudoaneurysm in order to exclude it. An
extension of the stent tract into the proximal SMA was carried out by a self-expanding
BMS (Protégé GPS, Medtronic, Minneapolis, MN) with a high radial strength.
Fig. 2 (case 5): Digital subtraction angiography (DSA) of IDSMA; a) before and b) after endovascular treatment using bare metal stents (BMS) (arrowheads), a covered
stent, and a self-expanding BMS (open arrowhead). In this special case, the distal
part of the dissection membrane was adapted by bare metal stenting, not to compromise
relevant jejunal side branches (star). However, as one of the two pseudoaneurysms
originated from the true lumen of the distal segment and could not be cannulated from
collateral vessels of the celiac trunk, it was excluded by coil embolization through
the struts of the stent (arrow, a: pseudoaneurysm, b: coils). The proximal aneurysm
was excluded by prolongation with a covered stent.
One patient presented with IDSMA plus stenosis of the CA ([Fig. 3]), which was treated via a 6-french sheath by placement of two balloon-expandable
uncovered stents into the CA (BeSmooth 10/17 and 10/23 mm, Bentley, Hechingen, Germany)
and by implantation of a balloon-expandable covered stent in the SMA (BeGraft 6/23 mm,
Bentley, Hechingen, Germany).
Fig. 3 (case 6): Images from a patient with symptomatic IDSMA initially presenting with
type IIa dissection. (a) CT scan in sagittal orientation clearly demonstrates dissection of the SMA and stenosis
of the celiac trunk. DSA after therapy in a corresponding angulation (b) shows free perfusion of the celiac trunk after implantation of a BMS and the excluded
dissection of the SMA after placement of a covered stent (open arrowheads).
After initial treatment, all of our patients (100 %) were symptom-free. During our
follow-up period, one patient developed minor progression of the diameter of the dissected
SMA after 6 years and significant progression after more than 17 years ([Fig. 4]). As the patient was disinclined to undergo surgery, he agreed to a watch-and-wait
strategy with close monitoring of symptoms by our surgical outpatient clinic. One
patient presented with stent tract occlusion approximately 30 months after interventional
treatment but did not show corresponding symptoms or imaging evidence of mesenteric
ischemia. In follow-up CT examinations, distal vessels were perfused via large-caliber
collaterals of the inferior mesenteric artery.
Fig. 4 (case 2): Patient with asymptomatic IDSMA (arrows a–c). CT examinations, each in the arterial contrast phase in axial slice orientation.
A progression of the diameter of the superior mesenteric artery (SMA) during a period
of more than 17 years is shown. The diameter of the true lumen remains stable, with
dilatation of the thrombosed part and increasing calcification of the vessel wall.
Diameters in a) 17 mm at baseline, b) 19 mm after 6 years, c) 28 mm after 17 years
All other patients did not develop worrisome changes of the SMA during the follow-up
period and thus did not need any further intervention.
Literature review
A literature search comprising the outlined criteria yielded 12 relevant publications:
two larger studies, three case series, and seven case reports. The relevant detailed
literature search is outlined in [Table 2].
Table 2
Literature review of patients with symptomatic IDSMA. AC: anticoagulation; AP: antiplatelet
agents; BP: optimization of blood pressure control; ET: endovascular therapy; “–”:
no further information in the manuscript.
Reference
|
Cases
|
Initial treatment
|
Results:
Pain resolution
|
Further treatment
|
Complications
|
Follow-up time/clinical outcome
|
Xu L., et al. (2020) [21]
|
42
|
Conservative: 15/42
AC/AP + BP
ET: 27/42
23 stenting + in 7 cases additional balloon angioplasty,
whereas 4/27 could not be treated by stenting
(guide wire could not enter the lumen)
|
Conservative: pain resolution 14/15
ET: pain resolution 26/27
|
1 conservatively treated patient with additional ET (stent) after 7 days/ pain resolution
1 patient (stent) with persisting abdominal
pain treated with ET/no further treatment
|
Conservative: No
ET: 1/27 (pseudoaneurysm formation in the brachial artery with exclusion by surgery)
|
38 patients mean follow-up time: 28.5 months
Conservative: 6 with recurrent pain during follow-up: 4/6 were successfully stented
ET: 4 patients who failed ET did not need further treatment
2/4 with pain recurrence,
2/4 with progression
|
Chu SY., et al. (2012) [24]
|
8
|
Conservative: 1/8 AP + BP
ET: 6/8 stent
|
Conservative:
pain resolution 1/8
ET:
pain resolution 6/8
|
No
|
1 patient without treatment died before intervention (hepatitis and multiple organ
failure).
ET: injury of a small SMA branch
|
Mean: 16 months/no recurrence
|
Katsura M., et al. (2011) [20]
|
3
|
Conservative:
1/3 watch-and-wait
ET: None 0/3
Surgical: bypass graft 2/3
|
Conservative:
Pain resolution 1/3
Surgical:
pain resolution 2/3
|
No
|
Thrombotic graft occlusion 1/3
|
Median: 4.3 years/no recurrence
|
Funahashi H., et al. (2016) [10]
|
2
|
Conservative: 1/2 AC + BP
1/2 BP
|
Pain resolution 2/2
|
No
|
No 2/2
|
1: 2 years/no recurrence
2: 5 years/no recurrence
|
Asif S., et al. (2019) [12]
|
1
|
Conservative: AC + BP
|
Pain resolution
|
No
|
No
|
2 weeks/no recurrence
|
Barnes S., et al. (2017) [14]
|
1
|
Conservative: AC
|
Pain resolution
|
No
|
No
|
–/–
|
Daoud H., et al. (2018) [13]
|
1
|
Conservative: AC + BP
|
Pain resolution
|
No
|
No
|
3 days/no recurrence
|
Ezeh KJ, et al. (2022) [17]
|
1
|
Conservative: AC
|
Pain resolution
|
No
|
No
|
–/–
|
Gao DN., et al. (2017) [19]
|
1
|
Conservative: AP + BP
|
Persistent pain for 5 days
|
Additional ET (stent)/pain resolution
|
No
|
6 months/no recurrence
|
Miyata T., et al. [15]
|
1
|
Conservative: AC + BP
|
Pain resolution
|
No
|
No
|
2 months/no recurrence
|
Subhas G., et al. (2009) [16]
|
1
|
Conservative:
AC
|
Pain resolution
|
No
|
No
|
5 years/no recurrence
|
Discussion
Our patient population exhibited risk factors like male gender and a history of smoking
that were in accordance with those in the literature for IDSMA [8]. In addition, half of our patients suffered from arterial hypertension. The majority
of patients was symptomatic, a finding that is also consistent with the clinical literature
[1]. Similar to other publications [5]
[8], IDSMA predominantly occurred in patients between the 4th and 6th decade of life
in our small series.
Conservative treatment
In the absence of any strict standards, conservative management consisting of a watch-and-wait
strategy and/or anticoagulation, antiplatelet, and antihypertensive therapy is the
most common treatment in approximately 62–89 % of patients [1]
[8]
[11]. This approach seems to be especially beneficial in patients without any symptoms
[1]. These findings are in line with the clinical outcome of our asymptomatic patients,
in whom conservative treatment was chosen and resulted in satisfying long-term results.
However, in one of our symptomatic patients, conservative management was also chosen
as the treatment of choice. In this case, the use of a covered stent was not considered
due to a lack of an adequate proximal and distal landing zone. On the one hand, placement
of such a stent could have compromised relevant side branches of the small bowel.
On the other hand, sealing of the dissection entry could have been hampered. The patientʼs
condition improved with adequate analgesics and antiemetics. Further CT follow-up
studies were performed several months after the acute onset of abdominal pain, with
the width of the dissected SMA remaining constant. As a result, further treatment
was not required.
However, in the literature it is pointed out that conservative medical treatment and
bowel rest is the most common initial treatment also in patients with symptoms. In
most cases, further treatment is not needed [12]
[13]
[14]
[15]
[16]
[17]
[18]. An important question is how to manage patients with persistent pain or those with
initial treatment failure. Previously published experience has shown that pain should
resolve after 2–5 days of initial conservative therapy [10]
[13]
[19]
[20].
A study with a larger cohort of patients showed that the recurrence rate of pain was
higher in conservatively treated patients in comparison to those in the endovascular
group, in which patients had been successfully treated by stenting [21]. As a consequence, the need for further treatment was slightly higher in the conservatively
treated group.
In general, in patients with longer-lasting pain, the regimen should be adjusted towards
endovascular or surgical therapy to avoid the risk of fatal complications [19]
[21].
Therefore, a cut-off point with pain lasting longer than 5–7 days seems to be the
right interval for reconsideration, with patients being under close clinical monitoring
during that time [10]
[13]
[19]
[20].
In our study population, there was no sign of recurrence of abdominal pain during
the follow-up.
Endovascular treatment
The need for endovascular therapy of IDSMA varies from 4 % to 33.6 % in the literature
and is an additional option in cases with persistent pain or aneurysms/pseudoaneurysms
and simultaneous stenosis of the CA [8]
[11]
[20]. In addition, a more recent study showed that endovascular treatment may prevent
the recurrence of symptoms and may also achieve complete remodeling of the dissection
compared to conservative therapy [21]. In one of our cases, DSA revealed a dissection of the SMA with the formation of
two pseudoaneurysms in the jejunal arcade region ([Fig. 2]), both originating from the true lumen. Initially, two BMSs were implanted in the
distal segment of the true lumen to readapt the dissecting membrane to the adventitial
layer and not to compromise the relevant jejunal side branches. As the distal pseudoaneurysm
originated from the true lumen of the distally stented segment and from collateral
vessels of the CA that could not be cannulated, coaxial microcoil embolization was
performed through the bare struts of the implanted stent. Using an overlapping technique,
a covered stent was placed in the more proximal segment in order to seal the entry
of a further pseudoaneurysm. Finally, a self-expanding nitinol stent was inserted
into the proximal segment ([Fig. 2]). Completion angiography demonstrated complete exclusion of the pseudoaneurysms
as well as preservation of the perfusion of the SMA. Post-interventional CTA did not
show any reperfusion of the pseudoaneurysms or evidence of mesenteric ischemia, while
the inserted stents were freely contrasted. In this case, interventional treatment
was the treatment of choice based on multidisciplinary consensus in terms of minimal
invasiveness and a hemodynamically stable patient. A deterioration in clinical status
and an impending hemorrhagic shock due to a ruptured pseudoaneurysm would have been
clear indications for surgical treatment [1]
[8]
[21]
[22]
[23]
[24].
To date, the role of oral antiplatelet therapy after stent implantation is not clear
in the setting of an IDSMA [25]. As demonstrated in patient 5, there is not any guarantee for long-term patency
since our patient showed stent occlusion after a follow-up of 30 months post interventional
treatment. However, it can be hypothesized that in this particular case, antiplatelet
therapy might have contributed to the development of progressive collateralization
in addition to the blood supply via vascular anastomoses of the CA and Riolan [26], thus preventing mesenteric ischemia and the recurrence of pain.
In contrast, in symptomatic two-vessel disease consisting of an IDSMA in combination
with significant stenosis of the CA and hence impaired collateralization, treatment
of both lesions seems to be indicated [11]
[22]
[27]
[28]. One of our patients therefore required stenting of both arteries. He was treated
with two balloon-expandable BMSs within the CA and implantation of a balloon-expandable
covered stent within the dissected SMA to seal the entry. Abdominal pain was significantly
reduced. In control series and follow-up examinations, the CA stenosis resolved without
subsequent compromise, making ligamentous stenosis unlikely ([Fig. 3]).
Possible complications that may occur after endovascular therapy are access site complications
in terms of pseudoaneurysm formation [21] or abdominal hematoma caused by injury of an SMA branch [24]. However, in our small case series, periprocedural complications were not encountered.
On the other hand, failure of endovascular therapy due to technical problems or persistent
abdominal pain does not seem to lead to a change in therapy, i. e., escalation to
a surgical approach [21].
Surgical treatment
In cases of persistent pain or long-standing stenosis involving multiple side branches
of the SMA, surgical treatment with patch angioplasty may be considered. Surgical
bypass may serve as an alternative option in the case of reduced blood flow of the
SMA. An absolute indication for surgical therapy in the form of bowel resection is
bowel necrosis [1]
[8]
[11]
[27]
[28]
[29]. However, as long as there is no evidence of bowel necrosis and the patient is hemodynamically
stable, endovascular therapy with recanalization may still be a therapeutic option,
especially in acute ischemia. After restoration of perfusion, a “second look” operation
may then be performed. Unfortunately, these cases are rare, because patients are usually
not transferred to the hospital before necrosis has developed [21].
Cases of surgical treatment are rarely documented in the literature. One publication
reported two cases with surgical intervention. In one of these two cases, there was
intraoperative evidence of ischemia, and in the other case, prolonged pain led to
bypass surgery. In one of these cases, thrombotic graft occlusion was reported on
follow-up CT, which did not lead to recurrence of abdominal pain, presumably due to
the development of collateral vessels [20]. Our patient, who was treated by surgical bypass, had an uneventful outcome. We
want to mention that signs of ischemia are not always present on CT, a fact that may
delay a surgical approach [20].
Follow-up
Management and follow-up beyond the acute setting can be challenging for all specialties
involved [1]
[8]
[11]. In the article by Acosta et al., it was shown that approximately 0.5 % of patients
required further treatment in the form of surgical or endovascular treatment at an
interval of 1–44 months after the initial diagnosis of SMA dissection [8] because of acute vessel occlusion and aneurysm formation after dissection [30]
[31]
[32]
[33]
[34].
CTA studies have shown that 43 % of conservatively treated patients had complete resolution
of the dissection at a mean of 22 months [8]. Further CTA studies showed that there was not any progression of the SMA diameter
or false lumen during an average period of 21 and 22 months [5]
[35]. A more recent article suggested that such complications may occur within the first
6 months in symptomatic patients. However, relevant changes do not tend to occur after
one year [36]. If progression of the diameter of the SMA and/or a compromise of bowel perfusion
has been verified, the respective case has to be reevaluated with special regard to
endovascular and surgical treatment options [1]
[8]. In particular, if the SMA diameter in the dissected area is more than 50 % larger
than in the unaffected area, or when a narrowing of more than 90 % of the true lumen
occurs [37]
[38], invasive or minimally invasive treatment approaches should be considered.
Long-term data on changes in the dissected SMA beyond a 6-year period are lacking
in the literature [8]. Due to the cumulative long-term risk, IDSMA can lead to life-threatening complications.
One case in our study showed that even after a long follow-up period of more than
17 years, progression may occur and may lead to a critical state with risk of rupture
([Fig. 4]). In this case DSA revealed a dissecting aneurysm of the SMA with exclusive supply
of the small bowel via the true lumen ([Fig. 5]). Therefore, interventional therapy would not have been an adequate option. In addition,
the patient was reluctant to undergo surgery. Our other patients did not show worsening
pathomorphological imaging findings of the SMA and recurrent abdominal symptoms during
the follow-up period. There was no further need for intervention at a mean follow-up
time of 68 months. These findings support the fact that long-term follow-up may be
warranted in those selected cases.
Fig. 5 (case 2): Follow-up: a) Corresponding sonographic control examination of the previously illustrated patient
with IDSMA type IIb. b) Due to progression of the diameter of IDSMA, DSA was perfomed, which revealed a
dissecting aneurysm of the SMA (false lumen: arrow) with exclusive supply of the small
bowel via the true lumen (arrow head); branches of the superior mesenteric artery
(stars).
Conclusion
To conclude, the appropriate diagnosis, treatment, and follow-up of IDSMA must be
tailored to the needs of the individual patient and require multidisciplinary decision
making. For the management of IDSMA in most symptomatic patients, we recommend observation
and conservative medical therapy with bowel rest, antihypertensive drugs, anticoagulation,
and/or antiplatelet agents. In the case of complications such as prolonged pain or
evidence of intestinal ischemia, endovascular or surgical therapy should be considered.
-
IDSMA is an increasingly frequently diagnosed entity.
-
Treatment of IDSMA is highly dependent on symptoms and radiomorphological aspects
and constellations.
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IDSMA requires multidisciplinary expertise.
Abbreviations
BMS:
bare metal stent
CA:
celiac trunk
CT:
computed tomography
CTA:
computed tomography angiography
CV:
cardiovascular
DSA:
digital subtraction angiography
IDSMA:
isolated dissection of the superior mesenteric artery
mg:
milligram
MRA:
magnetic resonance angiography
RAS:
renal artery stenosis
SD:
standard deviation
SMA:
superior mesenteric artery
US:
ultrasound
VAS:
visual analog scale