Isolated spontaneous dissection of the superior mesenteric artery treated by percutaneous stent placement: Case report
Article Outline
Acute ischemia due to spontaneous dissections of the superior mesenteric artery are uncommon events, with sporadic reports. Therapeutic options include clinical management, direct artery repair, bowel resection, and more recently, endovascular stenting. We present a case of abdominal pain due to superior mesenteric artery spontaneous isolated dissection treated with stent placement and with a favorable 31-month follow-up period.
Dissection of the superior mesenteric artery (SMA) is an event frequently associated with and considered an extension of aortic dissections.1, 2 However, in a small number of cases, spontaneous isolated SMA dissection were reported, and different therapeutic approaches suggested.3 Such dissections usually initiate in the SMA ostium, and an interesting therapeutic option may be the use of endovascular stents. We report a case of self-expanding stent placement to treat isolated spontaneous SMA dissection.
Case report
A 51-year-old man, with a previous history of moderate hypertension, presented a 1-day history of upper quadrant, low-intensity abdominal pain and nausea. Clinical examination was unspecific, with diffuse pain at palpation, but no evidence of peritoneal irritation. Bowel sounds were slightly augmented. The first diagnosis considered was of gastroenterocolitis, and discharge with symptomatic therapy was prescribed.
After 4 days, the patient presented a sudden worsening of pain with nausea and vomiting. Leukocyte count, lactate levels, conventional x-ray, and ultrasound were normal. The hypothesis of acute vascular disease was made, and a duplex-scan investigation showed a double-lumen image of the SMA with concomitant focal 8 mm dilation (Fig 1), but with normal velocities. A contrast-enhanced CT confirmed the duplex-scan findings without signs of bowel ischemia.
Fig 1.
Duplex-scan images of SMA dissection in longitudinal (left) and transversal view. The white arrows point the intimal flap.
On the same day, the patient was submitted to digital subtraction angiography (DSA) through the left femoral artery. No images of aortic dissection or of the celiac trunk and renal arteries were present. Isolated dissection of the SMA, about 0.5 cm distal to its origin was noted, leading to a 60% stenosis of the true lumen (Fig 2). The dissected area was relatively short, with distal branches preserved from dissection. Immediate option for endovascular therapy was made, and a self-expandable 8 × 36 mm stent (Wallstent, Boston Scientific, Natick, Mass) was delivered over the dissected area (Fig 2). A similar-diameter balloon was inflated to provide full expansion to the stent. Inflation was performed under low pressure to avoid excessive tension on the weakened vessel walls. The patient had almost immediate relief from symptoms, and was discharged after 2 days with full recovery of symptoms. Since the first months of follow-up, duplex-scan surveillance showed a focal increase in peak systolic velocity (PSV) in the transition between SMA trunk and proximal portion of the stent (Fig 3), with stable values along this period. The patient completed 31 months of follow-up period without symptoms.
Fig 2.
A, Side view angiogram of the SMA showing the dissection flap (black arrow) with false lumen in the upper portion. B, After stent deployment. C, Final angiogram after stent dilation.
Fig 3.
From left to right, duplex-scan surveillance images with 5, 17, and 26 months. Note the peak systolic velocities in the bottom left of each image.
Discussion
Isolated spontaneous dissection of the superior mesenteric artery is an uncommon finding. The postmortem incidence in a series of 6666 autopsies was 0.06%.4 In recent years, however, an increasing number of case reports have been published.5, 6, 7, 8
In this case report, we avoid to affirm that bowel ischemia was installed. Although this case carries some characteristics that suggest intestinal ischemia, the symptoms could be also related to the acute and continued vessel endothelial injury, which could be enhanced by augmented mesenteric flow induced by feeding. Although a 60% acute SMA stenosis could be observed, this finding may not lead to an acute intestinal ischemic event. Theoretically, the residual lumen, as well as collateral circulation from celiac trunk and inferior mesenteric artery should provide proper blood flow to avoid ischemia.
The use of percutaneous endovascular techniques to treat SMA lesions is feasible in many conditions.9, 10, 11 A rare event, spontaneous SMA dissection was first treated with conservative or surgical therapy. Percutaneous stent placement for SMA isolated dissection treatment was first related by Leung et al.7 Since then, only a few reports have been found describing endovascular therapy for such condition12, 13, 14, 15 (Table). In most of the cases, self-expandable stents with diameters up to 10 mm and overall lengths up to 10 cm were used. There are no evidence-based data to support the choice of the best stent type for such specific situation. We opted for a self-spanding stent because of its weaker radial force, once we did not want to submit the weakened artery wall to excessive tension. Froment et al14 described a case of stent therapy for SMA dissection, along with a review of 29 reported cases since 1975. The patients were submitted to several modalities of surgical approach, such as bowel resection, direct arterial repair, venous or prosthetic grafts, either isolated or combined. Also, 13 patients received only conservative treatment. Although the majority of patients showed good evolution, 38% of the individuals who had undergone the initial nonsurgical approach were submitted to surgery or stenting in early or late evolution. These observations suggest that early intervention, when feasible, may provide better results for SMA dissection than clinical therapy alone. The decision for early stent therapy in the present case, even without major signs of bowel ischemia, follows this rationale.
Table. Reported cases of spontaneous dissection of SMA treated by percutaneous stent placement
| Authors | Age/sex | Diagnosis | Stent type and dimensions | Result/follow-up |
|---|---|---|---|---|
| Leung et al, 2000 | 67, male | MRA | Self-expandable 8 × 68 mm | Technical success/asymptomatic after 6 months |
| Yoon et al, 2003 | 52, male | Duplex | Balloon-expandable 6 × 15 mm; Balloon-expandable 7 × 15 mm | Technical success/asymptomatic after 12 months |
| Kim et al, 2004 | 48, female | CECT | Self-expandable 08 × 70 mm | Technical success/asymptomatic restenosis after 6 months |
| Kim et al, 2004 | 54, male | CECT | Self-expandable 08 × 60 mm Second intervention: self-expandable 10 × 50 mm | Proximal aneurismatic dilation of celiacomesenteric trunk occurred after 4 months; a second stent delivered. |
| Asymptomatic 2 months after second intervention | ||||
| Froment et al, 2004 | 58, male | CECT | Self-expandable (2), 8 × 20 mm; Balloon-expandable, 7 × 28 mm | Technical success/asymptomatic after 18 months |
| Miyamoto et al, 2005 | 59, male | CECT | Self-expandable 10 × 60 mm; Self-expandable 10 × 40 mm | Technical success/asymptomatic after 03 months |
| Present case | 51, male | Duplex, CECT | Self-expandable 8 × 36 mm | Technical success/asymptomatic after 31 months |
Endovascular therapy is an attractive option for SMA dissection, since it can provide immediate relief from ischemia with minimal invasiveness. DSA can be considered a gold-standard diagnostic method, and extending the procedure with interventional proposals would result in a small increase in the amount of contrast used and the time of procedure.
We believe that both DSA and contrast enhanced CT can provide images of dissection of SMA proximal segments with very similar accuracy. But DSA will also provide details of distal segments, as well as images of eventually occluded branches through the way of the false lumen, features that only recently became possible by top-line CT systems. Thus, DSA should be seen not as an imposition to confirm the diagnosis, but as a tool for a better comprehension of the distal anatomy of the affected vessel.
In this case, the SMA approach was performed through the femoral artery, without difficulties. In our experience, femoral access to SMA is usually feasible, and arm arteries should be an exception choice access.
A limitation for stent-based intervention should be advanced bowel ischemia. But even in these cases, combined arterial stenting with eventual bowel resection would represent the possibility of a reduced magnitude surgery, avoiding artery manipulation and use of synthetic grafts or patches in a hostile and possibly contaminated cavity, in frequently unstable patients.
In chronic intestinal ischemia due to atherosclerotic SMA disease, surgery has shown better results of continued patency than single PTA or stenting,16 the latter presenting frequent necessity of re-intervention for assisted patency.17 These results cannot be freely extrapolated to SMA dissection stenting since the physiopathology of these conditions is different, but they suggest that the use of stents in the SMA for any reason should be followed up by a thorough surveillance schedule.
Duplex-scan is a useful tool in surveillance of vascular interventions. In this case, a persistent high PSV was continuously observed in the SMA trunk, with the presented values oscillating in a nonprogressive way. According to most authors, these values do not represent significant stenosis.18, 19, 20 Some authors19, 20 consider end diastolic velocity (EDV) more important than PSV, and in this case, EDV values were always below 30 cm/s in all surveillance measurements.
SMA dissection also can present vessel dilation as seen in this case, which can lead to aneurismatic changes, what strengthens the importance of regular follow-up with proper imaging exams.
In conclusion, a growing number of reports show the safety and efficacy of endovascular stent therapy for isolated SMA dissection. Regular follow-up of these rare cases is necessary to understand the long term results of this therapeutic option.
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Competition of interest: none.
PII: S0741-5214(07)01269-4
doi:10.1016/j.jvs.2007.07.051
© 2008 The Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.
