Transcranial Doppler Waveforms During Intra-aortic Balloon Pump Counterpulsation for Vasospasm Detection After Subarachnoid Hemorrhage.

Abstract

Transcranial Doppler ultrasound is a standard screening tool for vasospasm after subarachnoid hemorrhage. Prevention of vasospasm-induced delayed cerebral ischemia after subarachnoid hemorrhage depends on optimization of cerebral perfusion pressure, which can be challenged by neurogenic stress cardiomyopathy. Intra-aortic balloon pumps have been utilized to augment cerebral perfusion, but they change the transcranial Doppler waveform, altering its interpretability for vasospasm screening. To assess the features of the transcranial Doppler waveform that correlate with vasospasm. We retrospectively reviewed cases of subarachnoid hemorrhage that underwent same-day transcranial Doppler ultrasound and angiography. Transcranial Doppler waveforms were assessed for mean velocity, peak systolic velocity, balloon pump-augmented diastolic velocity, and a novel feature, "delta velocity" (balloon pump-augmented velocity - systolic velocity). Relationship of flow velocity features to vasospasm was estimated by generalized estimating equation models using a Gaussian distribution and an exchangeable correlation structure. There were 31 transcranial Doppler and angiography pairings (12 CT angiography/19 digital subtraction angiography) from 4 patients. Fourteen pairings had proximal vasospasm by angiography. Delta velocity was associated with proximal vasospasm (coefficient -6.8 [95% CI -9.8 to -3.8], P < .001). There was no significant correlation with proximal vasospasm for mean velocity (coefficient -13.0 [95% CI -29.3 to 3.4], P = .12), systolic velocity (coefficient -8.7 [95% CI -24.8 to 7.3], P = .29), or balloon pump-augmented velocity (coefficient -15.3 [95% CI -31.3 to 0.71], P = .06). Delta velocity, a novel transcranial Doppler flow velocity feature, may reflect vasospasm in patients with subarachnoid hemorrhage and intra-aortic balloon pumps.