Pseudoshock: A Challenging Presentation of Bilateral Subclavian Artery Stenosis
  • Adeel Nasrullah
    Division of Pulmonology and Critical Care, Allegheny Health Network, Pittsburgh, PA, USA
  • Romil Singh
    Department of Medicine, Allegheny Health Network, Pittsburgh, PA, USA
  • Amina Hamza
    Department of Medicine, Allegheny Health Network, Pittsburgh, PA, USA
  • Briana DiSilvio
    Division of Pulmonology and Critical Care, Allegheny Health Network, Pittsburgh, PA, USA


Bilateral subclavian artery stenosis, vertebrobasilar insufficiency, shock, pseudoshock, peripheral vascular disease, vasopressors


Introduction: Subclavian artery stenosis (SAS) is a manifestation of peripheral artery disease (PAD). Presentation varies, ranging from arm claudication and muscle fatigue to symptoms which reflect vertebrobasilar hypoperfusion, among which are syncope, ataxia and dysphagia. Although rare, severe bilateral SAS can exist and present as refractory hypotension. We describe a case of bilateral SAS masquerading as circulatory shock, or rather ‘pseudoshock’.

Case Description: A 59-year-old female patient presented to the emergency department with complaints of dark stools. She was anaemic and hypotensive and therefore suspected to have an acute gastrointestinal bleed (GIB) with resultant haemorrhagic shock. Her hypotension was unresponsive to fluid resuscitation and blood transfusions. Bilateral upper extremity radial artery catheters confirmed low blood pressures. After her blood pressure failed to improve despite the addition of several vasopressors, a femoral artery catheter (FAC) was placed, which revealed significant hypertension discordant with the hypotension measured by the radial artery catheters. Review of CT angiography of the upper extremities revealed the presence of bilateral SAS which was deemed to be the aetiology of the falsely low blood pressure.

Discussion: SAS should be suspected in patients with lower extremity PAD or a blood pressure (BP) differential of 15 mmHg or more between arms. When bilateral subclavian arteries are stenosed, this difference in BP may be concealed, making lower extremity BP measurements, as seen in non-invasive tests such as ankle brachial index (ABI) tests or through more invasive procedures such as FAC placement, critically important.

Conclusion: Bilateral SAS may present as pseudo-hypotension. In cases of refractory shock of unclear aetiology, especially in patients with known PAD, a high index of suspicion is warranted for ‘pseudoshock’ secondary to severe vascular stenosis. Comparison of upper and lower extremity BP via invasive arterial catheters or non-invasive ABI tests can aid in the diagnosis of bilateral SAS.



  • Ramin S, Michael HC, Warner PB, Arnost F, Julie OD, et al. Subclavian artery stenosis: prevalence, risk factors, and association with cardiovascular diseases. J Am Coll Cardiol 2004;44:618–623.
  • Hirata K, Nakazato J, Wake M, Takahashi T. Pseudo-hypotension with acute pulmonary oedema due to simultaneous bilateral subclavian artery stenosis in a patient with coronary artery bypass graft surgery using bilateral internal mammary arteries: a case report. Oxf Med Case Reports 2019;2019:omz038-omz.
  • Caesar-Peterson S, Bishop MA, Qaja E. Subclavian artery stenosis. Treasure Island (FL): StatPearls Publishing; 2021.
  • Standring S, Gray H, Borley N. Gray's anatomy: the anatomical basis of clinical practice. 40th ed. Amsterdam: Elsevier; 2021.
  • Rahimi O, Geiger Z. Anatomy, thorax, subclavian arteries. Treasure Island (FL): StatPearls Publishing; 2021.
  • Afari ME, Wylie JV, Carrozza JP. Refractory hypotension as an initial presentation of bilateral subclavian artery stenosis. Case Rep Cardiol 2016;2016:8542312.
  • Lakshman A, Singh C, Singhal M, Jain S, Sharma N, Kumari S, et al. A curious case of "septic shock". J Emerg Med 2017;52:e61–e63.
  • Potter BJ, Pinto DS. Subclavian steal syndrome. Circulation 2014;129:2320–2323.
  • Pollard H, Rigby S, Moritz G, Lau C. Subclavian steal syndrome: a review. Australas Chiropr Osteopathy 1998;7:20–28.
  • Khan TH, Farooqui FA, Niazi K. Critical review of the ankle brachial index. Curr Cardiol Rev 2008;4:101–106.
  • Khoury SR, Ratchford EV. Vascular disease patient information page: subclavian artery stenosis. Vasc Med 2021;26:464–468.
  • Byrne C, Tawfick W, Hynes N, Sultan S. Ten-year experience in subclavian revascularisation. A parallel comparative observational study. Vascular 2016;24:378–382.
  • Salman R, Hornsby J, Wright LJ, Elsaid T, Timmons G, Mudawi A, et al. Treatment of subclavian artery stenosis: a case series. Int J Surg Case Rep 2016;19:69–74.
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    Published: 2022-07-22
    Issue: 2022: Vol 9 No 7 (view)

    How to cite:
    Nasrullah A, Singh R, Hamza A, DiSilvio B. Pseudoshock: A Challenging Presentation of Bilateral Subclavian Artery Stenosis. EJCRIM 2022;9 doi:10.12890/2022_003495.