Diagnostic Criteria and Yield of Real-Time Transcranial Doppler Monitoring of Intra-Arterial Reperfusion Procedures

Abstract

Background and Purpose-Intra-arterial (IA) rescue procedures are increasingly used to treat acute ischemic stroke. We implemented continuous transcranial Doppler (TCD) monitoring during these procedures to detect any potentially harmful flow changes. Here, we report diagnostic criteria and yield of TCD monitoring. Methods-We studied consecutive acute stroke patients who underwent IA reperfusion procedures. TCD flow signatures during these procedures were analyzed and any abnormal findings were documented. Results-Patients were included only if there was successful insonation through the skull; of 56 eligible patients, 51 were included. IA procedures included IA tissue plasminogen activator, use of the Merci retriever, the Penumbra system, balloon angioplasty, and stenting. On TCD monitoring, contrast injections produced high-intensity signals and increased the mean flow velocity (MFV). Deployment of the Merci device appeared as high-intensity, short-duration signals with a transient MFV decrease of 11.5%. The Penumbra system produced lower-intensity signals with a greater transient decrease in MFV during aspiration. IA tissue plasminogen activator significantly increased MFV by 7.5% over Merci and Penumbra flow velocity changes. Power motion Doppler-TCD detected reocclusion in 13 patients, artery-to-artery embolization in 2 patients, air embolism in 2 patients, and hyperperfusion in 6 patients. Overall, the yield of TCD monitoring was positive in 23 (49%) patients who received IA reperfusion procedures. Conclusions-Our velocity, intensity, and flow signatures criteria for TCD monitoring of IA reperfusion procedures detect reocclusion, hyperperfusion, or thromboembolism and air embolism in nearly half of all procedures. This hemodynamic information can be particularly helpful when neurological assessment is limited or delayed. (Stroke. 2010;41:695-699.)

Vascular Imaging in Stroke: Comparative Analysis

“…Continuous TCD monitoring during intra-arterial rescue procedures may detect potentially harmful flow changes like re-occlusion, hypo-and hyper-perfusion or thromboembolism and air embolization, and it can be helpful particularly when neurological assessment in patients is limited because of sedation and intubations [62].…”

“…DSA, however, has a risk of peri-and post-procedural complications (e.g., embolism, dissections, retroperitoneal hematoma, allergic reactions to contrast medium, nephropathy), particularly in older patients with polyvascular atherosclerosis, resulting in a morbidity and mortality from 1 to 4% [62,63]. In the ACAS trial of patients with asymptomatic carotid artery stenosis, half of early stroke risk was attributed to performance of diagnostic catheter angiography [64].…”

Bringing Forward Reperfusion with Oxygenated Blood Perfusion beyond Arterial Occlusion during Endovascular Procedures in Patients with Acute Ischemic Stroke

“…The use of continuous TCD monitoring of the flow in the affected vessel confirms the establishment of blood flow in the otherwise stagnant arteries, adding a new indication for the use of TCD during IA procedures. 11 The idea of establishing catheter systems to reperfuse the brain across the occlusion was described and patented, 16 but to our knowledge, the technology was never applied beyond the initial prototype stage. Other studies theorized about inducing local hypothermia by perfusing cooling fluids beyond the clot to rapidly achieve the potential benefits of hypothermia, avoiding the systemic complications.…”

“…Pre-and postocclusion flow was continuously monitored with TCD during the procedure 11 (PMD100 Digital Transcranial Doppler System; Spencer Technologies, Seattle, Washington), and all changes were recorded. Recanalization was assessed with the TIMI grading score 12 at the end of the procedure.…”

Outcome Improvement in Acute Stroke Revascularization Procedures

“…9 The local hemodynamic effects of thrombolysis, mechanical thrombectomy, balloon angioplasty, and stenting are reviewed. Particulate and gaseous microembolic signals, resulting from arterial manipulations, were detected frequently.…”