Screening for subclinical subclavian artery stenosis before coronary artery bypass grafting: Should we do it?

Abstract

Atherosclerotic subclavian artery disease is detected in about 5% of patients referred for coronary artery bypass (CABG) surgery. The internal mammary artery, a branch of the subclavian artery, is the most frequently utilized graft to restore coronary circulation because of its longevity. Stenosis or occlusion of the subclavian artery can cause retrograde blood flow in the ipsilateral internal mammary artery, known as "steal," compromising coronary circulation supplied by the graft. Steal may be asymptomatic or may result in symptoms of myocardial ischemia. Symptomatic subclavian artery stenosis post bypass is referred to as coronary subclavian steal syndrome post-CABG. The incidence is not well defined, and the benefits of screening patients referred for CABG are not known. Despite the various modalities available to detect subclavian artery stenosis, current guidelines fail to provide guidance about screening high-risk patients for this entity. Detection of subclavian artery disease prior to CABG can reduce complications posed by post-mammary artery graft cardiac ischemia. This review discusses the utility of preoperative subclavian artery screening prior to CABG.

The Role of Color Doppler Ultrasonography in the Perioperative Period of Coronary Artery Bypass Grafting: Comparison with Transit-Time Flow Measurement

“…Spectral Doppler waveform of the SCA and IMA has been proven useful for predicting the degree of ipsilateral stenosis. Increased systolic velocity, spectral broadening, delayed systolic peak, and a change from a triphasic or biphasic waveform to a monophasic waveform distal to the obstruction indicate significant proximal SCA and IMA disease [14]). Subcutaneous emphysema on the left supraclavicular fossa was present in 2 patients, which resulted in an insufficient visualization of proximal LIMA through CDUS.…”

“…The LIMA is the preferred conduit for CABG because of the better biological characteristics and the better long-term patency that it presents [16-19]. However, disease proximal to the graft can impair flow and result in a retrograde flow or “steal” from the coronary circulation, with resultant myocardial ischemia [14, 20, 21]. CDUS is the noninvasive modality of choice in the evaluation for SCA and IMA disease.…”

Preoperative Assessment for Coronary Artery Bypass Graft: Going Back to the Basics

“…However, SCA stenosis or occlusion proximal to the origin of LITA may severely compromise the graft's flow, even if the internal thoracic artery (ITA) per se, is an otherwise disease-free graft. Therefore, this can potentially result in retrograde flow or steal phenomenon from the coronary circulation, with resultant myocardial ischemia [8]. The need for surgeons' awareness cannot be overemphasized, since detection of optimal ITA flow prior to CABG can reduce complications caused by post-ITA graft ischemia [4,6].…”

Proposal for Manual Osteopathic Treatment of the Phrenic Nerve

“…When the phrenic nerve enters the mediastinum, it crosses the internal mammary artery or internal thoracic artery near its origin (subclavian artery) [ 35 , 36 ]. The phrenic nerves enter the mediastinum together with the phrenic veins and arteries, constituting the pericardiacophrenic neurovascular bundle, passing in front of the pulmonary roots (above the middle of the mediastinal area), where major bronchi and the pulmonary arteries and veins are present [ 37 , 38 ].…”