One of the mainstay treatments of aneurysmal subarachnoid hemorrhage for DCI (delayed cerebral ischemia) secondary to cerebral vasospasm is triple-H therapy: hypervolemia, (relative) hypertension, and hemodilution; however, despite the fact that it is standard of practice, the efficacy of this therapy in improving clinical outcomes is not quite clear.

Here, 13 patients were randomized to induced hypertension and 12 patients were induced to no induced hypertension. Patients randomized to induced hypertension received intravenous norepinephrine drip for at least 24-48 hours until neurologic deficits improved, a complication occurred, or a maximum MAP of 130 mmHg or maximum SBP of 230 mmHg was reached. Although the control group did not undergo induced hypertension, the authors note that hypotension was avoided by giving vasopressors to avoid MAP < 80 mmHg. Change in cerebral blood flow (CBF) was calculated between the intervention and comparison group. There was no statistically significant difference in the change in CBF between the two groups; authors note that there was a trend towards improved CBF in follow up CTP in the lowest perfused region, but it does not appear to be statistically significant.  

At least in this small exploratory, no statistically significant improvement was seen with randomization to induced hypertension. A much larger study (authors note 225-250 patients per group would) be needed to find a statistically significant difference in change in overall CBF between intervention and control, and in fact, the trend towards improved CBF in areas of lowest perfusion suggests that an improvement may be detected with a larger sample size. In addition, there were some variables which could have confounded the study results including a higher proportion of high grade WFNS patients in the hypertension group. At this point, however, clinical practice is not likely to be impacted even in light of this negative study given the size of the study and possible confounders.