Objective: The outcomes of carotid angioplasty and stenting (CAS) are, in addition to patient baseline characteristics, highly dependent on the safety of the endovascular procedure. During the successive stages of CAS, transcranial Doppler (TCD) monitoring of the middle cerebral artery was used to assess the association of cerebral embolism and hemodynamic changes with transient (amaurosis fugax and transient ischemic attack) and persistent (minor and major stroke) cerebral deficits, and death.
Methods: By use of a prospectively completed database of 550 patients, the association of various TCD emboli and velocity variables with periprocedural cerebral outcome <or=7 days was evaluated by univariable and multivariable logistic regression analyses in combination with receiver operating characteristic (ROC) curve analyses. The impact of basic patient characteristics, such as age, sex, preprocedural cerebral symptoms, and ipsilateral carotid endarterectomy before CAS was also evaluated.
Results: We observed 36 patients with amaurosis fugax (n = 6; 1.1%) or transient ischemic attack (n = 30; 5.4%), 1 patient (0.2%) with an ipsilateral retinal infarct, and 21 patients with minor (n = 15; 2.7%) or major (n = 6; 1.1%) stroke, respectively. Five patients (0.9%) died. Multiple showers of microemboli (>5) at postdilation after stent deployment (odds ratio [OR] 2.6, 95% confidence interval [CI], 1.3 to 5.1), particulate macroembolus (OR, 27.0; 95% CI, 4.5 to 157), and massive air embolism (OR, 51.4; 95% CI, 5.4 to 492), as well as angioplasty-induced asystole and prolonged hypotension with a >70% reduction of middle cerebral artery blood flow velocities (OR, 6.4; 95% CI, 2.3 to 17.8) were independently associated with cerebral deficits. The ROC area of this model was 0.72. Of the patient characteristics, only preprocedural cerebral ischemia (OR, 5.0; 95% CI, 2.4 to 10.4) was associated with outcome. Adding this patient characteristic to the model, the area under the ROC curve increased to 0.80.
Conclusions: In CAS, in addition to such obviously adverse events as particulate macroembolism and massive air embolism, multiple microemboli (>5 showers) at postdilation after stent deployment and angioplasty-induced asystole and hypotension with a significant reduction of middle cerebral artery blood flow velocities are associated with periprocedural cerebral deficits. In combination with the presence of preprocedural cerebral symptoms, these four TCD monitoring variables reasonably differentiate between patients with and without adverse cerebral outcome. TCD monitoring provides insight into the pathogenesis of CAS related adverse cerebral events.