Signal reduction of donor artery on MRI after superficial temporal artery to middle cerebral artery anastomosis: a retrospective analysis.

Abstract

Microsurgical anastomosis from the superficial temporal artery (STA) to the middle cerebral artery (MCA) is a treatment option for appropriately selected patients with cranial atherosclerotic steno-occlusive disease (CASD). However, the long-term efficacy and patency of the donor artery remain unclear. We reviewed the signal intensity of the donor artery on magnetic resonance angiography (MRA) after STA-MCA anastomosis in patients with CASD and clarified the incidence of and risk factors for reduction in postoperative signal of STA. From April 2007 to March 2015, 155 STA-MCA anastomosis operations for CASD were performed at our institute. The postoperative imaging findings of 112 patients with available follow-up data for more than 3 months were retrospectively reviewed. Over a median follow-up of 24 months, the signal of the donor artery on MRA became weaker than that on MRA performed immediately after surgery in 30 (27%) patients. The rates of signal reduction at 1 and 2 years after surgery were 18 and 25%, respectively. Multivariate analysis revealed that a high STA bifurcation (p = 0.015; odds ratio, 7.14) and the presence of chronic kidney disease (p = 0.011; odds ratio, 5.59) were independent risk factors for postoperative signal reduction. Our results suggest that the signal intensity of the donor artery of an established STA-MCA bypass decreases in many cases. Both the loose entrance of the STA to the dura and systemic atherosclerosis are related to postoperative vessel remodeling.