Maureen M. Tedesco, Jason T. Lee, Janice J. Yeung, Barton Lane, Wei Zhou, Ronald L. Dalman.
Stanford University Medical Center, Stanford, Calif.
OBJECTIVES: We have previously demonstrated a 70% incidence of microemboli on diffusion weighted magnetic resonance imaging (DW-MRI) following carotid angioplasty and stenting (CAS). The purpose of this study is to compare the incidence of microemboli in two distinct time periods when procedural modifications were implemented into a CAS program.
METHODS: Following a retrospective quality review of our CAS cohort (n=27) from November 2004 through April 2006 (Period 1), we enrolled patients (n=22) from May 2006 through February 2008 (Period 2) undergoing CAS into a prospective cohort that included obtaining pre- and post-procedure DW-MRI exams. Procedural modifications during Period 2 included the preferential use of closed-cell systems (59%), early heparinazation, and elimination of performing a routine arch angiogram. The hospital records of these 49 patients were reviewed; symptoms, co-morbidities, lesion characteristics, peri-procedural information, and postoperative outcomes were collected. The incidence and location of acute, post-procedural microemboli were determined using DW-MRIs.
RESULTS: Twenty (74%) CAS patients from Period 1 and eight (36%) patients from Period 2 demonstrated acute microemboli on post-procedural DW-MRI (p=.02). The mean number of microemboli in Period 1 was 4.1±5.3 vs. 1.5±2.7 during Period 2 (p=.04). Three of the 27 patients (11%) during Period 1 experienced temporary neurologic changes that resolved within 36 hours. None of the patients during Period 2 exhibited any neurologic changes. There were no differences between the two groups with respect to demographics, comorbidities, and presenting symptoms. Period 2 patients when compared to Period 1 had more technically challenging anatomy with more calcified lesions (68% vs. 27%), longer lesions (15.9 mm vs. 8.2 mm), and higher incidence of ulceration (55% vs. 27%) (all p<.04).
CONCLUSIONS: Despite successful performance of 49 consecutive CAS procedures without permanent neurologic sequelae, significant reductions in peri-procedural embolic events as identified via DW-MRI lesions may be achieved through implementation of quality improvement measures identified through continuous outcome analysis. The long term neurologic benefits associated with reduced sub-clinical neurologic events remains to be determined.