Blood-brain barrier disruption after cardiac surgery

Abstract

Background and purpose—CNS complications are often seen after heart surgery, and postsurgical disruption of the blood-brain barrier (BBB) may play an etiologic role. The objective of this study was to determine the prevalence of MRI-detected BBB disruption (Hyperintense Acute Reperfusion Marker: HARM) and DWI lesions after cardiac surgery. Materials & methods—All patients had an MRI after cardiac surgery. In half the patients (group 1), we administered gadolinium 24 hours after surgery and obtained high-resolution DWI and FLAIR images 24-48 hours later. In the other half (group 2), we administered gadolinium at the time of the post-operative scan (2-4 days after surgery). Two stroke neurologists evaluated the images. Results—We studied 19 patients. None of the patients had clinical evidence of a stroke or delirium at the time of the gadolinium administration or the scan, but 9 patients (47%) had HARM (67% in group 1 and 30% in group 2, p=0.18) and 14 patients (74%) had DWI lesions (70% in group 1 and 78% in group 2, p=1.0). Not all patients with DWI lesions had HARM, and not all patients with HARM had DWI lesions (p=0.56). Conclusions—Almost half the patients undergoing cardiac surgery have evidence of HARM and three quarters have acute lesions on DWI after surgery. BBB disruption is more prevalent in the first 24 hours after surgery. These findings suggest that MRI can be used as an imaging biomarker to assess therapies that may protect the BBB in patients undergoing heart surgery