More Acute, Persisting Brain Lesions with Carotid Stenting Than Endarterectomy
Acute and persisting ischemic brain lesions are more likely to occur after carotid artery stenting (CAS) than after carotid endarterectomy (CEA), according to a substudy of the ICSS trial published online December 24, 2013, ahead of print in Stroke. However, the rate of conversion from acute to persisting lesions is lower in CAS patients, probably due to lower acute lesion volumes.
The International Carotid Stenting Study (ICSS) randomly assigned 1,713 patients with recently symptomatic carotid artery stenosis to CAS (n = 855) or CEA (n = 858). During the 120 days following randomization, there was a significantly greater risk of death, stroke, or MI among those who underwent stenting compared with endarterectomy.
For the ICSS-MRI substudy, researchers led by Leo H. Bonati, MD, of University Hospital Basel (Basel, Switzerland), looked at results of pretreatment conventional MRI, diffusion-weighted imaging (DWI) shortly after intervention, and fluid-attenuated inversion recovery (FLAIR) imaging at follow-up in 124 CAS and 107 CEA patients from the ICSS trial.
Risk Factors for Acute Lesions in CAS
CAS patients had more acute lesions than CEA patients (0.5 vs. 0; RR 8.8; 95% CI 4.4-17.5; P < 0.001). In the CAS group, there was at least a trend for increased acute lesions in patients who:
- Were older (≥ 71 years; RR 2.1; 95% CI 1.0-4.6; P = 0.067)
- Male (RR 2.4; 95% CI 1.00-5.8; P = 0.042)
- Had stroke as the qualifying event (RR 2.5; 95% CI 1.2-5.5; P = 0.021)
- Had more severe white matter disease (sum score ≥ 5; RR 2.4; 95% CI 1.1-5.3; P = 0.028)
CAS patients also had more persisting lesions (27 to 33 days post treatment) than CEA patients (RR 4.2; 95% CI 1.6-11.1; P = 0.005). However, the likelihood of conversion from acute (1 to 3 days post treatment) to persisting lesions was lower in the CAS group (RR 0.4; 95% CI 0.2-0.8; P = 0.007). No patient-level variable in either group predicted lesion conversion, although at the lesion level, volume of the acute lesion was associated with conversion (OR 1.7; 95% CI 1.5-2.1; P < 0.001).
The authors note that their study is in line with previous research showing that procedural ischemic stroke risks are increased in elderly patients treated with stents. “The association between acute lesion count and type of qualifying event may indicate that patients with a preceding stroke have particularly unstable plaques that are vulnerable to dislodgment of plaque debris or thrombus during stenting,” they observe. “White matter disease might be considered an indicator for increased vulnerability of the brain toward periprocedural embolism.”
The investigators add that in previous reports, the proportion of brain lesions persisting on follow-up FLAIR imaging ranged from 3% to 40% after stenting, and was 33% after CEA. “In contrast to these studies,” Dr. Bonati and colleagues add, “we were able to compare the rate of conversion from acute to persisting lesions between patients randomized to stenting or endarterectomy. Although stented patients had more persisting lesions, their conversion rate from acute to persisting lesions was lower than in the endarterectomy group, which was most likely explained by smaller acute lesions. In line with previous studies, acute lesion volume was the only predictor for lesion persistence.”
Clinical Impact of Persisting Lesions Unknown--but Unlikely
In an email correspondence with TCTMD, Dr. Bonati noted that although the main results were predictable, the “novel aspect [of the findings] was that we were able to compare the rate of conversion from acute to chronic lesions between CAS and CEA, as this was a randomized study,” he said.
“While the clinical significance of these lesions for the individual patient remains to be determined,” Dr. Bonati added, “novel protection devices that operate based on flow reversal appear to be superior [to] conventional protection devices to avoid cerebral emboli.”
Overall, “[t]he results on the rate of conversion from acute ischemic lesion to permanent tissue defect seen in this study are in line with clinical data showing that periprocedural strokes are more common with stenting, but that the long-term functional outcome appears to be equivalent to patients undergoing surgery,” Dr. Bonati said.
Rostamzadeh,A, Zumbrunn T, Jongen LM, et al. Predictors of acute and persisting ischemic brain lesions in patients randomized to carotid stenting or endarterectomy. Stroke. 2013;Epub ahead of print.
ICSS was funded by grants from the Medical Research Council, the Stroke Association, Sanofi-Synthélabo, and the European Union. Dr. Bonati reports receiving funding for travel from and serving on scientific advisory boards for Bayer.