Physiologic Functional Evaluation of Left Internal Mammary Artery Graft to Left Anterior Descending Coronary Artery Steal due to Unligated First Thoracic Branch in a Case of Refractory Angina

Abstract

Unligated side branches of the left internal mammary artery (LIMA) have been described in the literature as a cause of coronary steal resulting in angina. Despite a number of studies reporting successful side branch embolization to relieve symptoms, this phenomenon remains controversial. Hemodynamic evidence of coronary steal using angiographic and intravascular Doppler techniques has been supported by some and rejected by others. In this case study using an intracoronary Doppler wire with adenosine, we demonstrate that a trial occlusion of the LIMA thoracic side branch with selective balloon inflation can confirm physiologic significant steal and whether coil embolization of the side branch is indicated.

Exertional angina after cardiac bypass surgery successfully solved by endovascular occlusion of unligated lateral costal artery

“…Thus, the theory of CSP becomes doubtful. It is perhaps better to use the term diversion of systolic blood flow 5 8. Due to the unclear results of previous studies, several trials evaluating the haemodynamic consequences of unligated side branches of the IMA to coronary circulation and flow in an IMA have been carried out.…”

Left internal mammary artery side branch intervention in the management of coronary steal syndrome following coronary artery bypass grafting

“…Additionally, contrary to these studies, numerous case reports have yielded opposing results using Doppler flow velocity measurements 9–12 . Further, there is evidence that the presence of reversible anterior wall ischemia on pre‐angiography stress testing can predict differences in Doppler flow velocity measurements that improve with side branch occlusion 13 . Sawaya et al, for example, performed Doppler‐tipped flow velocity measurements in a symptomatic patient with a reversible LAD territory defect involving 10–15% of the left ventricular myocardium who had undergone LIMA‐LAD grafting roughly 10 years prior.…”

“…[9][10][11][12] Further, there is evidence that the presence of reversible anterior wall ischemia on pre-angiography stress testing can predict differences in Doppler flow velocity measurements that improve with side branch occlusion. 13…”

Combined Cardiac PET-CT and Transcatheter Closure for Left Internal Mammary Artery Side Branch Steal Syndrome

“…The left internal mammary artery (LIMA) side branch steal syndrome is a rare cause of refractory angina in patients after coronary artery bypass grafting (CABG) ( 1 ). However, the hemodynamic significance of large LIMA thoracic side branches and the potential clinical benefits of transcatheter side branch occlusion for angina relief remain controversial ( 2 ). Decision-making for LIMA side branch intervention in the management of LIMA side branch coronary steal syndrome relies on the documentation of myocardial ischemia and the effective contribution of the LIMA side branch to coronary blood flow in the native coronary artery ( 1 , 2 ).…”

“…However, the hemodynamic significance of large LIMA thoracic side branches and the potential clinical benefits of transcatheter side branch occlusion for angina relief remain controversial ( 2 ). Decision-making for LIMA side branch intervention in the management of LIMA side branch coronary steal syndrome relies on the documentation of myocardial ischemia and the effective contribution of the LIMA side branch to coronary blood flow in the native coronary artery ( 1 , 2 ). Cardiac positron emission tomography−computed tomography (PET-CT) represents an attractive noninvasive imaging modality to assess both myocardial ischemia and coronary blood flow, identifying patients with LIMA side branch steal phenomenon who may benefit from invasive treatment.…”