Idiopathic dissection from left subclavian artery to brachial artery: Spontaneous repair with conservative management

      Summary

      We report an unusual case of a 58-year-old female with idiopathic dissection of the left subclavian artery to the brachial artery which provoked vessel narrowing in the acute phase and was spontaneously repaired without surgical procedures in the chronic phase. We describe the serial imaging findings of the angiography and ultrasonography which demonstrate restoration of the dissection. In carefully selected patients, conservative management could be an alternative treatment to surgery or stenting with an excellent outcome.

      Keywords

      Introduction

      Idiopathic subclavian artery (SA) dissection is very rare. SA dissection has been reported with anomalies of the aortic arch and in an anatomically normal arch following trauma or iatrogenic injury during catheterization. Patients have been reported to present with chest and back pain and sometimes neurological symptoms [
      • Garewal M.
      • Selhorst J.B.
      Subclavian artery dissection and triple infarction of the nervous system.
      ,
      • Ananthakrishnan G.
      • Bhat R.
      • Zealley I.
      Spontaneous subclavian artery dissection causing ischemia of the arm: diagnosis and endovascular management.
      ,
      • Iwamuro Y.
      • Nakahara I.
      • Tanaka M.
      • Higashi T.
      • Watanabe Y.
      • Harada K.
      • Fujimoto M.
      • Oku T.
      Occlusion of the vertebral artery secondary to dissection of the subclavian artery case report.
      ].

      Case report

      A 58-year-old woman with hypertension was admitted to our hospital due to easy fatigability of her left arm for 5 months. The symptoms were unstable and intermittent. She had no history of pain in the left shoulder, catheterization, or injury such as from a traffic accident. On physical examination, the pulse in her left arm was weak and faint. Blood pressure in the right arm was 140/80 mmHg, and we were unable to measure blood pressure in the left arm. Her blood fibrin degradation product was 1.4 μg/ml and fibrin degradation product D-dimer was 0.4 μg/ml, so the possibility of thromboembolism was low. We therefore considered that her symptoms were due to vascular insufficiency. Three-dimensional computed tomography angiography (3D-CT) showed severe stenosis of the left SA, axillary artery, and brachial artery (BA), and a left SA aneurysm at a proximal site (Fig. 1a ). Ten days later, left SA angiography demonstrated mild stenosis of the left SA, severe stenosis of the left BA, and a left SA aneurysm at a proximal site (Fig. 1b). Ultrasonography (US) of the left SA to the BA showed an intimal flap and a true-lumen compressed by a thrombosed pseudo-lumen (Fig. 1c and d). She was diagnosed as having a dissection from the left SA to the BA. We selected conservative management with antiplatelet therapy to prevent acute occlusion with close follow-up, because her symptoms were spontaneously improving and her left radial artery became well palpable. Angiographic findings also improved over 10 days. Two weeks later, her symptoms disappeared and the second left SA angiography showed repair of the dissection (Fig. 2a ). Simultaneous intravascular US also showed the retraction of thrombosed pseudo-lumen (Fig. 2b). US of the left SA to BA showed retraction of the thrombosed pseudo-lumen and restoration of blood flow (Fig. 2c). The second 3D-CT angiography also demonstrated restored SA dissection, but the SA aneurysm remained (Fig. 2d).
      Figure thumbnail gr1
      Figure 1First three-dimensional computed tomography angiography showed severe stenosis of the left subclavian artery (SA), axillary artery, and brachial artery (BA) and a left SA aneurysm at a proximal site (a). First left SA angiography demonstrated mild stenosis of the left SA, severe stenosis of the left BA, and a left SA aneurysm at a proximal site (b). Gray scale images of first ultrasonography of the left BA showed an intimal flap (c). Two-dimensional color Doppler images of first ultrasonography of the left BA showed true-lumen compressed by a thrombosed pseudo-lumen (d).
      Figure thumbnail gr2
      Figure 2The second left subclavian artery (SA) angiography showed repair of the dissection (a). Intravascular ultrasonography of the left brachial artery (BA) showed the retraction of thrombosed pseudo-lumen (b). Two-dimensional color Doppler images of the second ultrasonography of the left BA showed retraction of the thrombosed pseudo-lumen and restoration of blood flow (c). Second three-dimensional computed tomography angiography demonstrated restored SA dissection but the SA aneurysm remained (d).

      Discussion

      SA dissection is a rare entity and is usually associated with anomalies of the aortic arch, trauma, and vascular catheterization [
      • Garewal M.
      • Selhorst J.B.
      Subclavian artery dissection and triple infarction of the nervous system.
      ]. Surgery and endovascular stent-graft treatment have been reported as conventional treatments of SA dissection [
      • Ananthakrishnan G.
      • Bhat R.
      • Zealley I.
      Spontaneous subclavian artery dissection causing ischemia of the arm: diagnosis and endovascular management.
      ,
      • Ilkay E.
      • Rahman A.
      • Ozdemir H.
      • Ozbay Y.
      • Yavuzskir M.
      • Burma O.
      Endovascular stent management of acute traumatic subclavian artery occlusion by intimal flap.
      ,
      • Guhathakurta S.
      • Agarwal R.
      • Borker S.
      • Sherma A.
      Chronic dissection of the left subclavian artery with pseudocoarctation.
      ]. On the other hand, there have been some reports of successful treatment of vascular dissection with conservative management using heparin and antiplatelets [
      • Frohwein S.
      • Ververis J.J.
      • Marshall J.J.
      Subclavian artery dissection during diagnostic cardiac catheterization: the role of conservative management.
      ]. Recently, a hybrid therapy with a conservative and an interventional approach was also reported for a long dissection from the SA to the BA [
      • Collins N.J.
      • Beecroft J.R.
      • Horlick E.M.
      Complex right subclavian artery dissection during diagnostic cardiac catheterization.
      ]. In our case, a surgical approach was difficult because of anatomic constraints, and exposure of a large area was required. Bypass surgery by synthetic vascular prosthesis from the left SA to the BA is fraught with the possibility of occlusion, insufficient blood flow of the branch, and neurological disorder. Stenting from the SA to the BA included the possibility of compression, deformation, migration, restenosis, occlusion or additional dissection, and lifelong antiplatelet medication is necessary. There is only a small number of case reports of stenting or surgery for SA dissection because of the rarity of the disease. Long-term prognosis and frequency of complications with these two therapies are unknown at present. Therefore no clear-cut recommendations could be made. At the first angiography, no sign of critical distal ischemia existed, her symptoms were improving and angiographical findings demonstrated that severe stenosis due to dissection was improved from the proximal site. We thought her dissection was in the natural recovery process, so conservative management with close follow-up was selected on the condition that whenever her symptoms deteriorated, emergency surgery could be performed. We used antiplatelet therapy without heparin because there was no critical ischemia [
      • McNeill D.H.
      • Dreisbach J.
      • Marsden R.J.
      Spontaneous dissection of the internal carotid artery: its conservative management with heparin sodium.
      ]. Two weeks later, angiography and echocardiography demonstrated an excellent outcome. In carefully selected patients, conservative management with close follow-up could be an alternative treatment to surgery or stenting with an excellent outcome. Conservative management can be indicated if there is the minimum necessary blood flow and the symptoms are not exacerbated. Spontaneous recovery may be expected under these conditions. Although blood pressure and symptoms are of course the most important indices during follow-up, we also considered US useful for the diagnosis and follow-up of dissection, because the dissection can be clearly visualized noninvasively.
      SA aneurysm is also a rare entity and is usually associated with atherosclerosis, trauma, thoracic outlet syndrome, and infection [
      • Davidović L.B.
      • Marković D.M.
      • Pejkić S.D.
      • Kovacević N.S.
      • Colić M.M.
      • Dorić P.M.
      Subclavian artery aneurysms.
      ]. The 3D-CT findings of our case suggested that the entry point of dissection was just distal to the takeoff of the left costocervical trunk and extended to the BA, and the entry point of the dissection subsequently became an aneurysm. Therefore, we speculated that idiopathic SA dissection may be one of the possible causes of SA aneurysm.

      Conclusions

      We presented an uncommon case of idiopathic dissection from the SA to the BA which showed spontaneous repair without surgery or stenting. In cases of unstable or intermittent symptoms of the upper limb such as easy fatigability or faint pulse, we must distinguish spontaneous artery dissection without pain or an episode of injury. In patients with dissection without critical ischemia, conservative management with close follow-up could be recommended to avoid unnecessary surgery or stenting. And in such cases, US is useful for the diagnosis and follow-up of the dissection.

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