Background: Delayed cerebral ischemia (DCI) is a common and serious complication of aneurysmal subarachnoid hemorrhage (aSAH). Though many clinical trials have looked at therapies for DCI and vasospasm in aSAH, along with reducing rebleeding risks, none have led to improving outcomes in this patient population. We present an up-to-date review of the pathophysiology of DCI and its association with early brain injury (EBI). Recent Findings: Recent studies have demonstrated that EBI, as opposed to delayed brain injury, is the main contributor to downstream pathophysiological mechanisms that play a role in the development of DCI. New predictive models, including advanced monitoring and neuroimaging techniques, can help detect EBI and improve the clinical management of aSAH patients. Summary: EBI, the severity of subarachnoid hemorrhage, and physiological/imaging markers can serve as indicators for potential early therapeutics in aSAH. The microcellular milieu and hemodynamic pathomechanisms should remain a focus of researchers and clinicians. With the advancement in understanding the pathophysiology of DCI, we are hopeful that we will make strides toward better outcomes for this unique patient population.

Objective Permissive hypertension may benefit patients with non-recanalized large vessel occlusion (nrLVO) post mechanical thrombectomy (MT) by maintaining brain perfusion. Data evaluating the impact of post-MT blood pressure (BP) levels on outcomes in nrLVO patients are scarce. We investigated the association of the post-MT BP course with safety and efficacy outcomes in nrLVO. Methods Hourly systolic BP (SBP) and diastolic BP (DBP) values were prospectively recorded for 24 hours following MT in consecutive nrLVO patients. Maximum, minimum, and mean BP levels were documented. Three-month functional independence (FI) was defined as modified Rankin Scale (mRS) scores of 0–2. Results A total of 88 nrLVO patients were evaluated post MT. Patients with FI had lower maximum SBP (160±19 mmHg vs 179±23 mmHg; P=0.001) and higher minimum SBP levels (119±12 mmHg vs 108±25 mmHg; P=0.008). Maximum SBP (183±20 mmHg vs 169±23 mmHg; P=0.008) and DBP levels (105±20 mmHg vs 89±18 mmHg; P=0.001) were higher in patients who died at 3 months while minimum SBP values were lower (102±28 mmHg vs 115±16 mmHg; P=0.007). On multivariable analyses, both maximum SBP (OR per 10 mmHg increase: 0.55, 95% CI 0.39 to 0.79; P=0.001) and minimum SBP (OR per 10 mmHg increase: 1.64, 95% CI 1.04 to 2.60; P=0.033) levels were independently associated with the odds of FI. Maximum DBP (OR per 10 mmHg increase: 1.61; 95% CI 1.10 to 2.36; P=0.014) and minimum SBP (OR per 10 mmHg increase: 0.65, 95% CI 0.47 to 0.90; P=0.009) values were independent predictors of 3-month mortality. Conclusions Our study demonstrates that wide BP excursions from the mean during the first 24 hours post MT are associated with worse outcomes in patients with nrLVO.

Introduction The optimal guidelines for post-mechanical thrombectomy (MT) blood pressure (BP) management are not well established. While observational studies have shown benefits of lowering BP in successfully recanalized patients to reduce the risk of reperfusion injury, there are no randomized trials to support this hypothesis. Recanalization may not always result in reperfusion and non infarcted area of brain in occluded arteries’ territory can remain hypo-perfused (no-reflow or stunned brain phenomena). Acute lowering of BP in this subgroup of successfully recanalized patients can potentially be harmful. Therefore, knowledge of the reperfusion status in the immediate post-MT period can potentially help determine the optimal BP target and provide prognostic information. Methods For each eligible study patient with LVO, a CBF study using Siemens ARTIS icono biplane will be performed immediately post MT while patient is on angiography table. We will retrospectively generate CTPpost maps (CBV, CBF, TTP and Tmax). Hypoperfusion will be defined as volume of Tmax delay ≥6 seconds in the affected vascular territory. Hyperperfusion will be defined as visual increase in CBF and CBV with reduced Tmax compared with the unaffected hemisphere. A retrospective correlative analyses of reperfusion status, recanalization grades, post thrombectomy BP levels with various outcome measures will be performed. We hypothesize that the successfully recanalized (based on angiography) and reperfused (based on cerebral blood flow analysis) patients would do better with lower levels of BP, whereas the patients with successful recanalization with incomplete reperfusion or unsuccessful recanalization would do better with higher BP levels. Technical Parameters of Perfusion Imaging and Injector Setup Imaging is done on a Siemens ARTIS icono biplane (Siemens Healthineers, Forchhiem, Germany) will consist of a 60 second multi-sweep protocol. The protocol includes 10 rotations of the c-arm which catch the mask, rise, and fall of the contrast injection into the patient. Contrast is injected radially through a 18 or 20 gauge IV at the start of the first rotation. Contrast injector is layered and filled with 80 ml of 100% saline followed by 70 ml of 100% contrast. The contents of the injector are not combined and remain layered so that the contrast is injected first followed by a saline chaser. Injection parameters are as follows: Contrast injection at 5 ml/sec to a total of 120 ml volume of contrast/saline layer at 300 PSI lax with a rise rate of 0.1 sec and no x-ray delay. Results 12 patients with LVO had the post MT CBF study using Siemens Icono perfusion protocol. We are in process of getting these images processed and generating CTP post maps (CBF, CBV, MTT and Tmax). The planned sample size is 100 patients. Conclusion Assessment of reperfusion status in immediate post MT period can potentially help understand the optimal BP target. Based on our single center study, we plan to conduct a prospective multicenter study to evaluate this hypothesis further. Disclosures N. Goyal: None. D. Alsbrook: None. M. Cornejo: None. J. Sequeiros: None. B. Krishnaiah: None. A. Arthur: None. V. Inoa: None. D. Hoit: None. J. DiNitto: None.