Case Reports

The Importance of Subclavian Angiography in the Evaluation of Chest Pain: Coronary-Subclavian Steal Syndrome

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Discussion

Long-term follow-up of LIMA as a conduit to LAD has shown a 10-year patency of 95% compared with 76% for saphenous vein and an associated 10-year survival of 93.4% for LIMA compared with 88% for saphenous vein graft.9,10 Because of the superiority of LIMA outcomes, it has become the preferred graft in CABG. However, this approach is associated with 0.1% to 0.2% risk of ischemia related to flow reversal in the LIMA b

ecause of CSSS.2

Greater awareness and improvement in diagnostic imaging have contributed to the increased incidence of CSSS and its consequences.2 Although symptoms related to myocardial ischemia, as in this case, are the most dominant in CSSS, other brachiocephalic symptoms, including vertebral-subclavian steal, transient ischemic attacks, and strokes, have been reported.11 Additionally, the same disease might compromise distal flow, resulting in extremity claudication or even distal microembolization.12

It is important to recognize that significant brachiocephalic stenosis has been reported in about 0.2% to 2.5% of patients undergoing elective CABG.6,8 Therefore, it is essential to screen for brachiocephalic artery disease before undergoing CABG. Different strategies have been suggested, including assessing pressure gradient between the upper extremities as the initial step; CSSS should be considered when the pressure gradient is > 20 mm Hg.

Other strategies include ultrasonic duplex scanning with provocation test using arm exercise or reactive hyperemia.13 Many high-volume centers are performing screening by proximal subclavian angiography in all patients undergoing coronary angiography. When significant disease is detected, arch aortography and 4-vessel cerebral angiography is performed.6 In addition, other centers have adopted the routine use of computerized tomographic angiography before CABG.14

Surgical correction of CSSS is considered to be the gold standard and can be accomplished by performing aorta-subclavian bypass, carotid-subclavian bypass, axillo-axillary bypass, or relocation of the IMA graft.2 Although this approach is invasive and carries many disadvantages related to patient comfort,surgical revascularization can be performed safely at the time of CABG and may not carry additional risk of morbidity or mortality.15 Moreover, surgical correction is the preferred modality for treatment of CSSS when the anatomy is not favorable for percutaneous intervention, such as chronic total occlusion of the subclavian artery.15Alternatively, CSSS can effectively be managed less invasively by percutaneous intervention, including PTA with stent placement,16,17 thrombectomy18 or atherectomy of the stenotic subclavian artery.19

In this patient, PTA was performed with primary stent placement. The lesion was crossed with a sheath, using combined femoral and radial access. After proper positioning, a balloon-expandable stent was deployed that resulted in complete angiographic resolution of the lesion and improvement of symptoms at 6-month follow-up. In line with previous reports, this case demonstrated that percutaneous intervention is a feasible and less invasive approach for management of CSSS.16,17 The effectiveness of the percutaneous approach has effectiveness equivalent to surgical bypass with minimal complications and good long-term success. Therefore, it has been suggested as first-line therapy in CSSS.8,16

Although preoperative screening for brachiocephalic disease before undergoing ipsilateral IMA coronary artery bypass can prevent the development of CSSS, there is controversy about the best approach for managing these concomitant conditions. Many institutions use all-vein coronary conduits, but that forgoes the benefit of a LIMA graft. Therefore, others still perform an IMA conduit after brachiocephalic reconstruction. An alternative method is to use free IMA or radial artery conduit. Currently, there are limited data about the use of endovascular treatment for brachiocephalic disease with a CABG.2

Conclusion

Coronary-subclavian steal syndrome is an important clinical condition that is associated with significant morbidity and mortality. In the Sullivan and colleagues report of 27 patients with CSSS, 59.3% had stable angina and 40.7% had acute coronary syndrome, among which 14.8% presented with acute MI.7 Therefore, early recognition is essential to prevent catastrophic consequences.

Patients with CSSS usually present with cardiac symptoms, but symptoms related to vertebral-subclavian steal and posterior cerebral insufficiency can coexist. The authors suggest routine preoperative screening for the presence of brachiocephalic disease, using ultrasonic duplex or angiography. This practice is cost-effective and essential to prevent the development of CSSS. Optimal management of brachiocephalic disease prior to CABG is debatable; however, IMA grafting and reconstruction of the brachiocephalic system seems to be a promising approach.

When CSSS develops after CABG, the condition can be successfully treated with percutaneous intervention and outcomes comparable with those of surgical bypass.

Acknowledgments
Special thanks to the division of cardiology at New Jersey VA Health Care System, in particular Steve Tsai, MD; Ronald L. Vaillancourt, RN, and Preciosa Yap, RN.

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