Protective STA-MCA bypass to prevent brain ischemia during high-flow bypass surgery: case series of 10 patients

Excerpt

Aboukais et al. present an article titled “Protective STA-MCA bypass to prevent brain ischemia during high-flow bypass surgery: case series of 10 patients.” [1] Using data from two institutions, the authors report the strategy of performing a STA-MCA bypass prior to completing a “high-flow” ECA-MCA bypass utilizing an interposition ulnar vein graft (UVG) for the purpose of flow replacement during aneurysm surgery. The cohort included 5 patients with ICA aneurysms (3 cavernous/paraclinoid, 1 terminus, 1 not specified), none of whom tolerated a balloon occlusion test or had anatomy suitable for placement of a flow diverter, and 5 with MCA bifurcation aneurysms. Mean total surgical time was 11 h (range 9–12 h). The mean recipient vessel occlusion time was 42 min (range 30–70 min) for STA-MCA bypasses and 51 min (range 37–65 min) for ECA-UVG-MCA bypasses. In addition to the STA-MCA and ECA-UVG-MCA bypasses, 2 patients underwent M2 MCA-M2 MCA bypasses. In total, 7 single- and 3 double-barrel STA-MCA bypasses were performed. Following creation of the bypasses, 7 patients underwent surgical parent artery occlusion while 3 patients underwent post-bypass endovascular parent artery occlusion. The authors did not perform intra-operative blood flow measurements nor did they utilize intra-operative neurophysiologic monitoring. Early (<7 days) angiographic follow-up showed patency of all bypasses except 1 ECA-UVG-MCA bypass and no patients had any new areas of restricted diffusion on post-operative MR imaging, when performed. Modified Ranking Scale (mRS) scores at 90 days improved from baseline in 1 patient, remained the same in 7 patients, and worsened in 2 patients, 1 of whom died secondary to an ICA dissection that led to a hemispheric infarction. The authors conclude that a “protective” STA-MCA bypass can reduce the risk of ischemic complications associated with high-flow bypass surgery. However, the authors do not include data from a control cohort of patients that did not undergo STA-MCA bypass to demonstrate that the risk of “high-flow” ECA-MCA bypass alone is unacceptably high. …