Elevated levels may prove to be a simple means of predicting which patients will develop cerebral hyperperfusion syndrome, researchers say.
Measuring global cerebral oxygen extraction fraction by blood sampling may be a fairly simple way of helping to predict which patients will develop cerebral hyperperfusion syndrome following carotid artery stenting (CAS), according to a retrospective analysis published online March 6, 2018, in the Journal of NeuroInterventional Surgery.
Cerebral hyperperfusion syndrome occurs at a rate of 0.2% to 18.9% among patients who undergo carotid revascularization, report the authors, led by Tomonori Iwata, MD (Saiseikai Fukuoka General Hospital, Fukuoka, Japan). The condition is associated with serious morbidity and mortality. Thus, there is a need to predict its occurrence.
One predictor of hyperperfusion syndrome, they write, is stage 2 hemodynamic failure, defined as a critical reduction in cerebral blood flow and a compensatory increase in oxygen extraction fraction in the ischemic brain. While this can be measured using PET, not all hospitals have access to this expensive technology. SPECT with acetazolamide challenge is another option, but this test is not definitive and intravenous use of acetazolamide has been linked with acute heart failure.
The authors, therefore, set out to determine whether global cerebral oxygen extraction fraction, obtained via blood sampling, could be used to anticipate stage 2 hemodynamic failure and thus predict cerebral hyperperfusion syndrome.
For this prospective trial, Iwata and colleagues calculated oxygen extraction fraction by blood sampling just before and after 134 patients underwent coronary artery stenting. Prior to the procedure, patients’ median global cerebral oxygen extraction fraction was 0.41. After the procedure, it was 0.42.
Nine patients developed cerebral hyperperfusion syndrome, and they had a higher median global cerebral oxygen extraction fraction before CAS than those who did not develop the syndrome. After CAS, median oxygen extraction fraction was not significantly higher in patients with who developed hyperperfusion syndrome, although there was a nonsignificant trend toward higher values.
Global Cerebral Oxygen Extraction Fraction by Presence of Cerebral Hyperperfusion Syndrome
|
Median (IQR) |
With (n = 9) |
Without (n = 125) |
P Value |
|
Before Stenting |
0.47 (0.41-0.50) |
0.41 (0.36-0.45) |
0.027 |
|
After Stenting |
0.51 (0.38-0.52) |
0.42 (0.38-0.46) |
0.058 |
Scattergrams of patients with and without hyperperfusion syndrome revealed that the cutoff values for prediction of the condition were 0.46 prior to stenting (P < 0.01) and 0.49 post-CAS (P < 0.001).
If oxygen extraction fraction “can be easily measured in institutions where CAS or [carotid endarterectomy] is performed, it will provide interventionalists or neurovascular surgeons with useful and accurate information about cerebral oxygen metabolism,” write the authors. This study demonstrates that detection of elevation of global cerebral oxygen extraction fraction by blood sampling “allowed for anticipation of [cerebral hyperperfusion syndrome] following CAS,” they conclude, particularly if elevated global cerebral oxygen extraction fraction is identified after stenting.
Source:
Iwata T, Mori T, Tanno Y, et al. Measurement of oxygen extraction fraction by blood sampling to estimate severe cerebral hemodynamic failure and anticipate cerebral hyperperfusion syndrome following carotid artery stenting. J NeuroInterv Surg. 2018;Epub ahead of print.
Disclosures:
Iwata reports no relevant conflicts of interest.
