Low carotid stump pressure as a predictor for ischemic symptoms and as a marker for compromised cerebral reserve in octogenarians undergoing carotid endarterectomy
Sam Tyagi, Matthew Dougherty, Keith Calligaro, Douglas Troutman, Danielle Pineda, Hong Zheng.
Pennsylvania Hospital, Philadelphia, PA, USA.
Introduction The majority of strokes due to carotid stenosis are thought to have an embolic etiology rather than related to cerebral hypoperfusion. In our practice, we usually measure stump pressure (SP) during carotid endarterectomy (CEA). We questioned whether cerebral hypoperfusion, as reflected by low SP, correlated with neurologic symptoms both pre-operative and peri-operatively. CREST trial data suggested a dramatically elevated procedural stroke risk in patients over 80, and it has been suggested that this reflected elevated embolic risk from aortic arch disease. We analyzed our data comparing elderly patients with others, specifically looking at the impact of stump pressure. Methods We reviewed our prospectively maintained database for CEA performed between January 1, 1992 and December 31, 2015. A low SP was defined as a systolic pressure less than 50 mm Hg. We preferentially perform CEAs under cervical block anesthesia. Shunts were utilized for neurologic changes in patients under cervical block anesthesia and for low SP in patients under general anesthesia. Results During this time period, 1403 CEAs were performed, and SP was recorded in 1190 cases. Of this latter group, 343 (28.9%) were symptomatic and 847 (71.1%) were asymptomatic. Of these, 192 CEAs (16.1%) were performed on octagenarians. Symptomatic patients were more likely to have a low SP (35.6%) compared to asymptomatic patients (26.2%)(p=0.0015). Patients having a low SP also had a higher postoperative stroke rate (2.9%) compared with patients with high SP (0.9%)(p=0.0174). Octogenarians were more likely to have a low SP (35.7%) compared to patients less than 80 years old (27.7%)(p=0.0328). Symptomatic patients with low SP had equivalent perioperative stroke rates regardless whether they were older (7.4%) or younger (5.3%) than 80 years old (p=0.6497). Conclusion While plaque material embolization may be the principal cause of symptoms with carotid bifurcation disease, symptomatic patients undergoing CEA are significantly more likely to have lower SP, raising the possibility that hypoperfusion plays a more important role in the etiology of stroke than previously thought. The symptomatic low SP group is at highest risk for peri-operative stroke, despite selective shunting based on neurologic changes and low SP. Octogenarians have a lower SP regardless of symptomatic status. This finding suggests hypoperfusion may account for the increased stroke rate seen in this population, perhaps reflecting decreased cerebral reserve.
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