Impact of different perioperative intraluminal shunt insertion methods on final patient outcomes after carotid endarterectomy in a sample of 250 patients
Abstract
Background and purpose Carotid endarterectomy (CEA) is a common and effective surgical method of stroke prevention. The procedure is performed under general anesthesia and is usually accompanied by simultaneous intraoperative somatosensory evoked potential (SEP) monitoring.
If a more than 50% decrease in N20/P25 SEP wave amplitude in 3 or more recordings occurs during surgery, a shunt is inserted. Shunt surgery is associated with higher risk of vessel wall injury and possible central embolization.
In an effort to minimize the number of shunted patients, we modified shunt insertion timing criteria according to intraoperative SEP changes and reviewed a sample of patients for whom this modified approach was utilized. Methods 250 patients (171 males, 79 females, mean age = 67.00 +- 8.55 SD, max. 86, min. 45) indicated for CEA were retrospectively enrolled in the study.
Shunting criteria included long-term loss of SEP that was not affected by full anesthesia with elevated mean arterial pressure and increased sedation. Neurological complications (measured as changes in NIHSS) were recorded and compared.
Results The overall incidence of perioperative adverse events (i.e. stroke/death) following CEA was 2.8% (2.0 and 0.8% in 5 and 2 patients, respectively). A drop in SEP was observed in 68 cases (27.2%).
Early persistent declines in cortical response amplitude that developed into complete persistent SEP amplitude loss resulted in shunt placement in 5 cases (2.0%). Perioperative neurological complications were observed in all patients and independently of intraoperative SEP response development (2.9% in patients with SEP loss vs. 2.7% in the remainder of the sample, p = 0.79).
Conclusion Surgery with modified shunt insertion timing demonstrated standard results. Due to the potential for vessel wall injury and embolization it is crucial to pay attention to shunt insertion timing in accordance with the individual course of surgery and intraoperative SEP development.