Background and purpose: Cerebral hyperperfusion syndrome (CHS) including intracranial hemorrhage (ICH) is a serious complication after carotid artery stenting (CAS). Therefore, in Japan, neuroendovascular physicians commonly evaluate the CHS risk of the CAS candidates using various pre-procedural imaging tests and sometimes perform preventive procedures against CHS, such as staged angioplasty (SAP; balloon angioplasty with an undersized balloon followed by delayed CAS) reported by Yoshimura et al. We conducted a nationwide questionnaire survey to clarify the current status of pre-procedural evaluation of the CHS risk and outcomes of high-risk patients of CHS who underwent CAS (including SAP) in Japan.
Methods: Questionnaires were mailed to neuroendovascular therapy experts certified by the Japanese society in June 2014, regarding imaging tests to evaluate the CHS risk and the total number of the patients who underwent CAS with or without 30-day adverse event (CHS, ICH, stroke or death) between October 2007 and March 2014.
Results: Responses were obtained from 154 institutes enrolling 363 experts (35.3% of all the certified experts). Pre-procedural imaging tests to evaluate the CHS risk were introduced in 144 institutes (93.5%) and single photon emission CT (SPECT) was mostly used in 88.2% of the institutes. A total of 7114 patients (7470 lesions) who underwent CAS with pre-procedural imaging tests was registered, including 1269 high-risk patients of CHS (1305 lesions, 17.5%). The rates of CHS and ICH in the high-risk patients were significantly higher than those of the non-high-risk patients (6.0% vs 0.4% [p<0.01] and 3.1% vs 0.3% [p<0.01], respectively). SAP was performed in 184 high-risk patients (189 lesions, 14.5%). SAP tended to reduce CHS (6.5% to 3.2%, p=0.08) of high-risk patients although modestly increase ischemic stroke (3.2 to 4.2%, p=0.51). The composite stroke or death rate of the SAP group was not different from that of the single-stage CAS group (6.1% vs 5.8%, p=0.88).
Conclusion: Most of the CAS candidates were stratified according to the CHS risk by SPECT in Japan, and CHS was developed in 6.5% of the high-risk patients who underwent single-stage CAS and in 3.2% of those who underwent SAP. To prove the efficacy of SAP, further study is needed.