A survey of blood pressure parameters after aneurysmal subarachnoid hemorrhage

Blood Pressure Management in Early Aneurysmal Subarachnoid Hemorrhage: A National Cross-Sectional Survey of Canadian Intensivists and Cerebrovascular Neurosurgeons

BACKGROUND

In aneurysmal subarachnoid hemorrhage (aSAH), rebleeding of the culprit aneurysm is associated with significant morbidity and mortality. Blood pressure reduction to specific target levels, with the goal of preventing rebleeding, has been a mainstay of care prior to definitively securing the aneurysm. Clinical practice guidelines have recently changed and no longer recommend specific blood pressure targets. This survey aims to identify the reported practice patterns and beliefs regarding blood pressure management during the early phase of aSAH.

METHODS

We conducted a self-administered, Web-based survey of critical care physicians and cerebrovascular neurosurgeons practicing in Canada. The questionnaire contained 21 items, including 3 case-based scenarios to elicit blood pressure target selection, both before and after aneurysm securing.

RESULTS

In the presecured period, systolic blood pressures of 160 mm Hg (50% [144 of 287]) and 140 mm Hg (42% [120 of 287]) were the most frequently selected upper-limit targets. In the postsecured period, a systolic blood pressure of 180 mm Hg (32% [93 of 287]) was the most frequently selected upper-limit target, but there was a wide distribution of targets selected across all three cases ranging from 100 to > 200 mm Hg. A mean arterial pressure of 65 mm Hg was the most common lower-limit target in both the presecured and postsecured periods. There was little change in blood pressure targets with increasing clinical severity. Predictors of higher or lower blood pressure target selection and barriers to implementation of the desired target were identified.

CONCLUSIONS

During the presecured period, nearly half of the reported upper-limit blood pressure targets are lower than previous guideline recommendations. These targets remain consistent despite increasing clinical severity and could potentially exacerbate cerebral ischemia and negatively impact clinical outcomes. In the postsecured period, there is wide variation in the reported blood pressure targets. A clinical trial is urgently needed to guide decision-making.

Comparison of the Effects of Blood Pressure Parameters on Rebleeding and Outcomes in Unsecured Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Elevated systolic blood pressure (SBP) has been linked to preprocedural rebleeding risk and poor outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH). This study seeks to compare the effects of SBP and mean arterial pressure (MAP) on rebleeding and functional outcomes in aSAH patients.

METHODS

We performed a retrospective study of a prospectively collected cohort of consecutive patients with aSAH admitted to an academic center in 2016-2023. Binary regression analysis was used to determine the association between BP parameters and outcomes including rebleeding and poor outcome defined as modified Rankin Scale 4-6 at 3 months postdischarge.

RESULTS

The cohort included 324 patients (mean age 57 years [standard deviation 13.4], 61% female). Symptomatic rebleeding occurred in 34 patients (11%). Higher BP measurements were recorded in patients with rebleeding and poor outcome, however, only MAP met statistical significance for rebleeding (odds ratio {OR} 1.02 for 1 mmHg increase in MAP, 95% confidence interval {CI}: 1.001-1.03, P = 0.043; OR 1 per 1 mmHg increase in SBP, 95% CI 0.99-1.01; P = 0.06)) and for poor outcome (OR 1.01 for 1 mmHg increase in MAP, 95% CI: 1.002-1.025, P = 0.025; OR 1 for 1 mmHg increase in SBP, 95% CI: 0.99-1.02, P = 0.23) independent of other predictors.

CONCLUSIONS

MAP may appear to be slightly better correlated with rebleeding and poor outcomes in unsecured aSAH compared to SBP. Larger prospective studies are needed to identify and mitigate risk factors for rebleeding and poor outcome in aSAH patients.

Intraoperative Blood Pressure and Carbon Dioxide Values during Aneurysmal Repair and the Outcomes after Aneurysmal Subarachnoid Hemorrhage

Cerebral autoregulation impairment is a critical aspect of subarachnoid hemorrhage (SAH)-induced secondary brain injury and is also shown to be an independent predictor of delayed cerebral ischemia (DCI) and poor neurologic outcomes. Interestingly, intraoperative hemodynamic and ventilatory parameters were shown to influence patient outcomes after SAH. The aim of the current study was to evaluate the association of intraoperative hypotension and hypocapnia with the occurrence of angiographic vasospasm, DCI, and neurologic outcomes at discharge. Intraoperative data were collected for 390 patients with aneurysmal SAH who underwent general anesthesia for aneurysm clipping or coiling between January 2010 and May 2018. We measured the mean intraoperative blood pressure and end-tidal carbon dioxide (ETCO2), as well as the area under the curve (AUC) for the burden of hypotension: SBP below 100 or MBP below 65 and hypocapnia (ETCO2 < 30), during the intraoperative period. The outcome measures were angiographic vasospasm, DCI, and the neurologic outcomes at discharge as measured by the modified Rankin scale score (an mRS of 0-2 is a good outcome, and 3-6 is a poor outcome). Univariate and logistic regression analyses were performed to evaluate whether blood pressure (BP) and ETCO2 variables were independently associated with outcome measures. Out of 390 patients, 132 (34%) developed moderate-to-severe vasospasm, 114 (29%) developed DCI, and 46% (169) had good neurologic outcomes at discharge. None of the measured intraoperative BP and ETCO2 variables were associated with angiographic vasospasm, DCI, or poor neurologic outcomes. Our study did not identify an independent association between the degree of intraoperative hypotension or hypocapnia in relation to angiographic vasospasm, DCI, or the neurologic outcomes at discharge in SAH patients.

Therapies for Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) is one of the most important complications of subarachnoid hemorrhage. Despite lack of prospective evidence, medical rescue interventions for DCI include hemodynamic augmentation using vasopressors or inotropes, with limited guidance on specific blood pressure and hemodynamic parameters. For DCI refractory to medical interventions, endovascular rescue therapies (ERTs), including intraarterial (IA) vasodilators and percutaneous transluminal balloon angioplasty, are the cornerstone of management. Although there are no randomized controlled trials assessing the efficacy of ERTs for DCI and their impact on subarachnoid hemorrhage outcomes, survey studies suggest that they are widely used in clinical practice with significant variability worldwide. IA vasodilators are first line ERTs, with better safety profiles and access to distal vasculature. The most commonly used IA vasodilators include calcium channel blockers, with milrinone gaining popularity in more recent publications. Balloon angioplasty achieves better vasodilation compared with IA vasodilators but is associated with higher risk of life-threatening vascular complications and is reserved for proximal severe refractory vasospasm. The existing literature on DCI rescue therapies is limited by small sample sizes, significant variability in patient populations, lack of standardized methodology, variable definitions of DCI, poorly reported outcomes, lack of long-term functional, cognitive, and patient-centered outcomes, and lack of control groups. Therefore, our current ability to interpret clinical results and make reliable recommendations regarding the use of rescue therapies is limited. This review summarizes existing literature on rescue therapies for DCI, provides practical guidance, and identifies future research needs.

Racial differences in time to blood pressure control of aneurysmal subarachnoid hemorrhage patients: A single-institution study

BACKGROUND AND PURPOSE

Aneurysmal subarachnoid hemorrhage occurs in approximately 30,000 patients annually in the United States. Uncontrolled blood pressure is a major risk factor for aneurysmal subarachnoid hemorrhage. Clinical guidelines recommend maintaining blood pressure control until definitive aneurysm securement occurs. It is unknown whether racial differences exist regarding blood pressure control and outcomes (HLOS, discharge disposition) in aneurysmal subarachnoid hemorrhage. Here, we aim to assess whether racial differences exist in 1) presentation, 2) clinical course, and 3) outcomes, including time to blood pressure stabilization, for aSAH patients at a large tertiary care medical center.

METHODS

We conducted a retrospective review of adult aneurysmal subarachnoid hemorrhage cases from 2013 to 2019 at a single large tertiary medical center. Data extracted from the medical record included sex, age, race, insurance status, aneurysm location, aneurysm treatment, initial systolic and diastolic blood pressure, Hunt Hess grade, modified Fisher score, time to blood pressure control (defined as time in minutes from first blood pressure measurement to the first of three consecutive systolic blood pressure measurements under 140mmHg), hospital length of stay, and final discharge disposition.

RESULTS

194 patients met inclusion criteria; 140 (72%) White and 54 (28%) Black. While White patients were more likely than Black patients to be privately insured (62.1% versus 33.3%, p < 0.001), Black patients were more likely than White patients to have Medicaid (55.6% versus 15.0%, p < 0.001). Compared to White patients, Black patients presented with a higher median systolic (165 mmHg versus 148 mmHg, p = 0.004) and diastolic (93 mmHg versus 84 mmHg, p = 0.02) blood pressure. Black patients had a longer median time to blood pressure control than White patients (200 minutes versus 90 minutes, p = 0.001). Black patients had a shorter median hospital length of stay than White patients (15 days versus 18 days, p < 0.031). There was a small but statistically significant difference in modified Fisher score between black and white patients (3.48 versus 3.17, p = 0.04).There were no significant racial differences present in sex, Hunt Hess grade, discharge disposition, complications, or need for further interventions.

CONCLUSION

Black race was associated with higher blood pressure at presentation, longer time to blood pressure control, but shorter hospital length of stay. No racial differences were present in aneurysmal subarachnoid hemorrhage associated complications or interventions.

Management of Poor-Grade Aneurysmal Subarachnoid Hemorrhage and Key Pearls for Achieving Favorable Outcomes: An Illustrative Case

Poor-grade aneurysmal subarachnoid hemorrhage (aSAH) is associated with high patient mortality. Despite recent advances in management strategies, the prognosis for poor-grade aSAH remains dismal. We present a challenging case of a patient presenting with poor-grade aSAH. A 46-year-old female presented to the emergency department after losing consciousness following a sudden headache. The examination showed a dilated left pupil and a Glasgow Coma Scale of 4. Imaging revealed a ruptured anterior communicating artery (ACoM) aneurysm, after which the patient was subsequently taken to the neuro-interventional radiology suite. We showed that carefully managing blood pressure and intracranial pressure (ICP) makes it possible to achieve a favorable outcome and reduce the risk of secondary brain injury in aSAH, regardless of patient presentation. We propose maintaining blood pressure at <160 mmHg prior to intervention, after which it can be permitted to increase to 160-240 mmHg for the purpose of preventing vasospasm. Additionally, transcranial doppler (TCD) is essential to detect vasospasm due to the subtility of symptoms in patients with aSAH. Once identified, vasospasm can be successfully treated with balloon angioplasty. Finally, targeted temperature management (TTM), mannitol, hypertonic saline, and neuromuscular paralysis are essential for the postoperative management of ICP levels.

Intraarterial Nimodipine Versus Induced Hypertension for Delayed Cerebral Ischemia: A Modified Treatment Protocol

Background:

Rescue treatment for delayed cerebral ischemia (DCI) after subarachnoid hemorrhage can include induced hypertension (iHTN) and, in refractory cases, endovascular approaches, of which selective, continuous intraarterial nimodipine (IAN) is one variant. The combination of iHTN and IAN can dramatically increase vasopressor demand. In case of unsustainable doses, iHTN is often prioritized over IAN. However, evidence in this regard is largely lacking. We investigated the effects of a classical (iHTN+IAN) and modified (IAN only ) treatment protocol for refractory DCI in an observational study.

Methods:

Rescue treatment for DCI was initiated with iHTN (target >180 mm Hg systolic) and escalated to IAN in refractory cases. Until July 2018, both iHTN and IAN were offered in cases refractory to iHTN alone. After protocol modification, iHTN target was preemptively lowered to >120 mm Hg when IAN was initiated (IAN only ). Primary outcome was noradrenaline demand. Secondary outcomes included noradrenaline-associated complications, brain tissue oxygenation, DCI-related infarction and favorable 6-month outcome (Glasgow Outcome Scale 4–5).

Results:

N=29 and n=20 patients were treated according to the classical and modified protocol, respectively. Protocol modification resulted in a significant reduction of noradrenaline demand (iHTN+IAN 0.70±0.54 µg/kg per minute and IAN only 0.26±0.20 µg/kg per minute, P <0.0001) and minor complications (15.0% versus 48.3%, unadjusted odds ratio, 0.19 [95% CI, 0.05–0.79]; P <0.05) with comparable rates of major complications (20.0% versus 20.7%, odds ratio, 0.96 [0.23–3.95]; P =0.95). Incidence of DCI-related infarction (45.0% versus 41.1%, odds ratio, 1.16 [0.37–3.66]; P =0.80) and favorable clinical outcome (55.6% versus 40.0%, odds ratio, 1.88 [0.55–6.39]; P =0.32) were similar. Brain tissue oxygenation was significantly higher with IANonly (26.6±12.8, 39.6±15.4 mm Hg; P <0.01).

Conclusions:

Assuming the potential of iHTN to be exhausted in case of refractory hypoperfusion, additional IAN may serve as a last-resort measure to bridge hypoperfusion in the DCI phase. With close monitoring, preemptive lowering of pressure target after induction of IAN may be a safe alternative to alleviate total noradrenaline load and potentially reduce complication rate.

Blood Pressure in Acute Stroke and Secondary Stroke Prevention

PURPOSE OF REVIEW

Hypertension is common in patients presenting with stroke and is independently associated with unfavorable outcomes. This article reviews current guidelines for early management of blood pressure (BP) and highlights the findings of recent investigative works.

RECENT FINDINGS

Intensive blood pressure reduction after receiving alteplase has not been shown to improve outcomes. Patients with large vessel occlusions may benefit from lower blood pressure targets post-intervention. Retrospective analyses of large intracerebral hemorrhage trials suggest that specific subgroups of patients may disproportionately benefit from or be harmed by intensive BP reduction. Robust data for management of blood pressure in subarachnoid hemorrhage patients is lacking and expert consensus continues to guide decision-making. Despite the impact of hypertension on outcomes, most prospective trials assessing efficacy of blood pressure reduction have yielded neutral or inconclusive results. Further trials are necessary to determine which patient populations are most likely to benefit from blood pressure control.

Optimal Cerebral Perfusion Pressure During Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage

OBJECTIVES

The recommendation of induced hypertension for delayed cerebral ischemia treatment after aneurysmal subarachnoid hemorrhage has been challenged recently and ideal pressure targets are missing. A new concept advocates an individual cerebral perfusion pressure where cerebral autoregulation functions best to ensure optimal global perfusion. We characterized optimal cerebral perfusion pressure at time of delayed cerebral ischemia and tested the conformity of induced hypertension with this target value.

DESIGN

Retrospective analysis of prospectively collected data.

SETTING

University hospital neurocritical care unit.

PATIENTS

Thirty-nine aneurysmal subarachnoid hemorrhage patients with invasive neuromonitoring (20 with delayed cerebral ischemia, 19 without delayed cerebral ischemia).

INTERVENTIONS

Induced hypertension greater than 180 mm Hg systolic blood pressure.

MEASUREMENTS AND MAIN RESULTS

Changepoint analysis was used to calculate significant changes in cerebral perfusion pressure, optimal cerebral perfusion pressure, and the difference of cerebral perfusion pressure and optimal cerebral perfusion pressure 48 hours before delayed cerebral ischemia diagnosis. Optimal cerebral perfusion pressure increased 30 hours before the onset of delayed cerebral ischemia from 82.8 ± 12.5 to 86.3 ± 11.4 mm Hg (p < 0.05). Three hours before delayed cerebral ischemia, a changepoint was also found in the difference of cerebral perfusion pressure and optimal cerebral perfusion pressure (decrease from -0.2 ± 11.2 to -7.7 ± 7.6 mm Hg; p < 0.05) with a corresponding increase in pressure reactivity index (0.09 ± 0.33 to 0.19 ± 0.37; p < 0.05). Cerebral perfusion pressure at time of delayed cerebral ischemia was lower than in patients without delayed cerebral ischemia in a comparable time frame (cerebral perfusion pressure delayed cerebral ischemia 81.4 ± 8.3 mm Hg, no delayed cerebral ischemia 90.4 ± 10.5 mm Hg; p < 0.05). Inducing hypertension resulted in a cerebral perfusion pressure above optimal cerebral perfusion pressure (+12.4 ± 8.3 mm Hg; p < 0.0001). Treatment response (improvement of delayed cerebral ischemia: induced hypertension+ [n = 15] or progression of delayed cerebral ischemia: induced hypertension- [n = 5]) did not correlate to either absolute values of cerebral perfusion pressure or optimal cerebral perfusion pressure, nor the resulting difference (cerebral perfusion pressure [p = 0.69]; optimal cerebral perfusion pressure [p = 0.97]; and the difference of cerebral perfusion pressure and optimal cerebral perfusion pressure [p = 0.51]).

CONCLUSIONS

At the time of delayed cerebral ischemia occurrence, there is a significant discrepancy between cerebral perfusion pressure and optimal cerebral perfusion pressure with worsening of autoregulation, implying inadequate but identifiable individual perfusion. Standardized induction of hypertension resulted in cerebral perfusion pressures that exceeded individual optimal cerebral perfusion pressure in delayed cerebral ischemia patients. The potential benefit of individual blood pressure management guided by autoregulation-based optimal cerebral perfusion pressure should be explored in future intervention studies.

Goal-directed Fluid Therapy Versus Conventional Fluid Therapy During Craniotomy and Clipping of Cerebral Aneurysm: A Prospective Randomized Controlled Trial

BACKGROUND

Fluid imbalance is common after aneurysmal subarachnoid hemorrhage and negatively impacts clinical outcomes. We compared intraoperative goal-directed fluid therapy (GDFT) using left ventricular outflow tract velocity time integral (LVOT-VTI) measured by transesophageal echocardiography with central venous pressure (CVP)-guided fluid therapy during aneurysm clipping in aneurysmal subarachnoid hemorrhage patients.

METHODS

Fifty adults scheduled for urgent craniotomy for aneurysm clipping were randomly allocated to 2 groups: group G (n=25) received GDFT guided by LVOT-VTI and group C (n=25) received CVP-guided fluid management. The primary outcome was intraoperative mean arterial pressure (MAP). Secondary outcomes included volume of fluid administered and several other intraoperative and postoperative variables, including neurological outcome at hospital discharge and at 30 and 90 days.

RESULTS

There was no difference in MAP between the 2 groups despite patients in group G receiving lower volumes of fluid compared with patients in group C (2503.6±534.3 vs. 3732.8±676.5 mL, respectively; P<0.0001). Heart rate and diastolic blood pressure were also comparable between groups, whereas systolic blood pressure was higher in group G than in group C at several intraoperative time points. Other intraoperative variables, including blood loss, urine output, and lactate levels were not different between the 2 groups. Postoperative variables, including creatinine, duration of postoperative mechanical ventilation, length of intensive care unit and hospital stay, and incidence of acute kidney injury, pneumonitis, and vasospasm were also comparable between groups. There was no difference in neurological outcome at hospital discharge (modified Rankin scale) and at 30 and 90 days (Extended Glasgow Outcome Scale) between the 2 groups.

CONCLUSION

Compared with CVP-guided fluid therapy, transesophageal echocardiography-guided GDFT maintains MAP with lower volumes of intravenous fluid in patients undergoing clipping of intracranial aneurysms with no adverse impact on postoperative complications.

A Questionnaire Survey of Management of Patients with Aneurysmal Subarachnoid Haemorrhage in Poland

BACKGROUND

Aneurysmal subarachnoid haemorrhage (aSAH) remains a potentially devastating threat to the brain with a serious impact on mortality and morbidity. We attempted to investigate correspondence between the current guidelines for aSAH management and real clinical practice in Poland.

METHODS

A web-based questionnaire was performed between 03.2019 and 06.2019. Centres performing neuro-interventional radiology procedures and neuro-critical care were included (n = 29). One response from each hospital was recorded.

RESULTS

In three (10.4%) centres, there was no clear protocol for an interventional treatment plan. Endovascular embolisation was predominantly used in 11 (37.9%) hospitals, and microsurgical clipping, in 10 (34.5%). A written protocol for standard anaesthetic management was established only in six (20.7%) centres for coiling and in five (17.2%) for microsurgical clipping. The diagnosis of cerebral vasospasm was based on transcranial Doppler as the first-choice method in seven (24.1%) units. "3-H therapy" was applied by 15 (51.8%) respondents, and "2-H therapy", by four (13.8%) respondents. In only eight (27.6%) centres were all patients with aSAH being admitted to the ICU.

CONCLUSION

Many discrepancies exist between the available guidelines and clinical practice in aSAH treatment in Poland. Peri-procedural management is poorly standardised. Means must be undertaken to improve patient-oriented treatment and care.

Endogenous arterial blood pressure increase after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Spontaneous blood pressure rise is a frequently observed phenomenon following aneurysmal subarachnoid hemorrhage (SAH). Facing the risk of aneurysmal rebleeding and the occurrence of delayed cerebral ischemia it is unclear how to react to these endogenous-driven blood pressure changes, as their predictive value for clinical course and functional outcome is still unknown.

PATIENTS AND METHODS

Endogenous blood pressure characteristics within 21 days after SAH were retrospectively analyzed in 93 patients. Any use of vasopressors for active induction of hypertension marked the end of data collection. Mean arterial blood pressure (MAP) was related to the onset of cerebral vasospasm and patient characteristics (Hunt&Hess, age, pre-existing hypertension, antihypertensive therapy, sedation). Predictors for cerebral infarction and functional outcome were calculated using a logistic regression model.

RESULTS

A significant MAP increase was observed in all patients from day 3 to day 7. Patients developing cerebral vasospasm had an overall steeper increase of MAP during this period (11.1 ± 11.4 mmHg vs. 6.5 ± 8.9 mmHg, p = 0.04). MAP rise started already 3 days before detection of vasospasm. Lower MAP values were recorded in patients with poor Hunt&Hess grade, under sedation and thus in patients with poor outcome. MAP had no impact on the development of cerebral infarction. In univariate analysis MAP on day 5 (OR 0.95, 95 %-CI: 0.89-0.99), MAP on day 6 (OR 0.95, 95 %-CI: 0.91-1.00), Hunt&Hess grade (OR 1.72, 95 %-CI: 1.14-2.60), sedation (OR 17.04, 95 %-CI: 2.08-139.51) and stroke (OR 5.82, 95 %-CI: 1.63-20.82) were predictors for poor outcome. In multivariable analysis, only sedation (OR 13.72, 95 %-CI: 1.62-115.94) and ischemic stroke (OR 4.48, 95 %-CI: 1.16-17.31) remained significant.

CONCLUSION

Spontaneous MAP increase occured in all patients following SAH. It was highly influenced by clinical parameters, thereby limiting its prognostic value for functional outcome. However, a steep increase of MAP might be an early clinical marker to identify patients at risk for developing cerebral vasospasm.

The Management of Hypertension in Pre-Aneurysmal Treatment Subarachnoid Hemorrhage Patients

BACKGROUND

Management of hypertension in subarachnoid hemorrhage patients within the preaneurysmal treatment period remains ambiguous, in part due to the lack of high-level, evidence-based guidelines. Despite this, current recommendations offer guidance regarding certain parameters (e.g., mean arterial pressure, systolic blood pressure). However, managing hypertension within this critical period is difficult because a fine balance must be achieved between lowering blood pressure enough to minimize the risk of rebleeding and preventing reduced cerebral perfusion and subsequent ischemic damage. Furthermore, the different causes of hypertension within the preaneurysmal treatment period are polyfactorial and include pathophysiologic responses, sympathetic nervous system activation, and iatrogenic from hyperdynamic therapy and vasopressors, which requires consideration for these patients to receive optimal management. Other factors including loss of autoregulation and concomitant conditions must also be considered when deciding whether to start antihypertensive therapy.

METHODS

We review the literature and provide a comprehensive update on management of hypertension within the preaneurysmal treatment period, which we hope stresses the need for better evidence-based guidelines that will in turn help manage this cohort.

RESULTS

Thorough review revealed no high-grade, evidence-based guidelines to manage these patients, which results in variation in clinical practice among different clinicians and institutions. Despite this, current recommendations seem reasonable until such guidelines are established.

CONCLUSIONS

It is clear that further, larger studies are warranted in order to clarify the effect of antihypertensive therapy on patient outcome and what the BP thresholds are, along with establishing the best treatment, for commencing antihypertensive therapy.

Posterior Reversible Encephalopathy Syndrome as a Complication of Induced Hypertension in Subarachnoid Hemorrhage: A Case-Control Study

BACKGROUND

Induced hypertension (IH) remains the mainstay of medical management for delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH). However, raising blood pressure above normal levels may be associated with systemic and neurological complications, of which posterior reversible encephalopathy syndrome (PRES) has been increasingly recognized.

OBJECTIVE

To ascertain the frequency and predisposing factors for PRES during IH therapy.

METHODS

We identified 68 patients treated with IH from 345 SAH patients over a 3-yr period. PRES was diagnosed based on clinical suspicion, confirmed by imaging. We extracted additional data on IH, including baseline and highest target mean arterial pressure (MAP), comparing PRES to IH-treated controls.

RESULTS

Five patients were diagnosed with PRES at median 6.6 d (range 1-8 d) from vasopressor initiation. All presented with lethargy, 3 had new focal deficits, and 1 had a seizure. Although baseline MAP (prior to DCI) did not differ between cases and controls, both MAP immediately prior to IH (112 vs 90) and highest MAP targeted were greater (140 vs 120 mm Hg, both P < .01). Magnitude of MAP elevation was greater (54 vs 34 above baseline, P = .004) while degree of IH was not (37 vs 38 above pre-IH MAP). All 4 surviving PRES patients had complete resolution with IH discontinuation.

CONCLUSION

PRES was diagnosed in 7% of SAH patients undergoing IH therapy, most often when MAP was raised well above baseline to levels that exceed traditional autoregulatory thresholds. High suspicion for this reversible disorder appears warranted in the face of unexplained neurological deterioration during aggressive IH.

Spontaneous Elevation of Blood Pressure After SAH: An Epiphenomenon of Disease Severity and Demand, But Not a Surrogate for Outcome?

BACKGROUND

Spontaneous blood pressure increase is frequently observed after aneurysmal subarachnoid hemorrhage (aSAH). These episodes of spontaneous blood pressure alterations are usually tolerated under the assumption of an endogenous response to maintain cerebral perfusion. The relevance of blood pressure variability and its relationship to disease severity and outcome, however, remain obscure.

METHODS

A total of 115 consecutive patients with aSAH were included for this retrospective analysis of a continuously collected data pool. Demographics, initial clinical severity of aSAH (HH°, mFS), treatment modality, clinical course, and outcome (development of DCI, cerebral infarction, and GOS after 3 months) were recorded. Hemodynamic information-recorded automatically with a frequency of 1/15 min-was analyzed for spontaneous blood pressure increase (SBI) and endogenous persistent hypertension (EPH) after exclusion of iatrogenic factors and relevant co-medication. Subgroup analysis included stratification for day 0-3, 4-14, and 14-21.

RESULTS

SBI and EPH incidence varied from 17 to 84% depending on detection threshold (15-35 mmHg) and time period under scrutiny. Incidence of blood pressure increase correlated with disease severity upon admission (p < 0.05), but the anticipated association with outcome was not observed. SBI and EPH were more likely to occur between day 4 and 14 (p < 0.001), but only early occurrence (day 0-3) was associated with higher incidence of DCI (p < 0.05). Persistent blood pressure elevation between day 4 and 21 was associated with fewer DCI. However, no influence of spontaneous upregulation on clinical outcome after three months was observed.

CONCLUSIONS

Spontaneous hemodynamic upregulation is a frequent phenomenon after aSAH. Our data support the hypothesis that spontaneous blood pressure alterations reflect an endogenous, demand-driven response correlating with disease severity. Early alterations may indicate an aggravated clinical course, while later upregulation in particular-if permitted-does not translate into a higher risk of unfavorable outcome.