Risk of intracerebral haemorrhage from hypertension is greatest at an early age

Introduction

The risk of intracerebral haemorrhage (ICH) associated with hypertension (HTN) is well documented. While the prevalence of HTN increases with age, the greatest odds ratio (OR) for HTN as a risk for ischemic stroke is at an early age. We sought to evaluate if the risk for ICH from HTN was higher in the youngest patients of each race.

Patients and methods

The Ethnic/Racial Variations of ICH (ERICH) study is a prospective multicenter case-control study of ICH among whites, blacks, and Hispanics. Participants were divided into age groups based on race-specific quartiles. Cases in each race/age group were compared to controls using logistic regression (i.e., cases and controls unmatched). The probability of ICH among cases and controls for each race were compared against independent variables of HTN, quartile of age and interaction of quartile and age also using logistic regression.

Results

Overall, 2033 non-lobar ICH cases and 2060 controls, and 913 lobar ICH cases with 927 controls were included. ORs were highest in the youngest age quartile for non-lobar haemorrhage for blacks and Hispanics and highest in the youngest quartile for lobar haemorrhage for all races. The formal test of interaction between age and HTN was significant in all races for all locations with the exception of lobar ICH in whites (p = 0.2935).

Discussion

Hypertension is a strong independent risk factor for ICH irrespective of location among persons of younger age, consistent with the hypothesis that first exposure to HTN is a particularly sensitive time for all locations of ICH.

Abstract P448: Axial versus Vertical Area of Intracerebral Hemorrhage and Outcome

Background: Intracerebral hemorrhage (ICH) has the highest morbidity and mortality rate of the major stroke subtypes. Volume is a well-established predictor of outcome. Theoretically, ICH should expand more in areas of less resistance. We hypothesize that 1) expansion perpendicular to neural tracts (axially) will be less great than expansion parallel to tracts (vertically) and 2) differing effect on outcome will occur based on axial and vertical areas of hemorrhage.

Methods: The Genetic and Environmental Risk Factors of Hemorrhagic Stroke (GERFHS) study is a population-based case-control study. Each case of ICH within the 5 county region of Greater Cincinnati was evaluated for volume of hemorrhage with a subset completing 3 month telephone follow-up to obtain data including modified Rankin Scale (mRS). Baseline variables were assessed for poor outcome, defined as mRS greater than or equal to 3 at 90 days.

Results: From July 2009 to December 2012, 1205 cases of ICH were identified, of which 304 had 3-month follow up. The table presents univariate association with outcome. More than 86% of hemorrhages had greater vertical area than axial area. On multivariable analysis controlling for ICH score variables, vertical area showed a trend toward worse outcome (OR 1.09, p= 0.06) vs axial area (OR 0.97, p=0.69) which was not found to have a significant effect on outcome independent of total volume.

Conclusion: Most patients have greater vertical expansion of ICH than axial expansion. This pattern of hemorrhage growth is consistent with neural tracts having less resistance vertically. If the greater impact on outcome is confirmed, improved outcome and trial inclusion criteria may be determined.

Abstract P625: Rate of Hemorrhagic Transformation After Ischemic Stroke and Associated Risk Factors: The Greater Cincinnati/Northern Kentucky Stroke Study (GCNKSS)

Background: Hemorrhagic transformation (HT) of ischemic stroke can have devastating consequences, leading to longer hospitalizations, increased morbidity and mortality. We sought to identify the rate of HT in stroke patients not treated with tPA within a large, biracial population.

Methods: The GCNKSS is a population-based stroke epidemiology study from five counties in the Greater Cincinnati region. During 2015, we captured all hospitalized strokes by screening ICD-9 codes 430-436 and ICD-10 codes I60-I68, and G45-46. Study nurses abstracted all potential cases and physicians adjudicated cases, including classifying the degree of HT. Patients treated with thrombolytics were excluded. Incidence rates per 100,000 and associated 95% confidence intervals (CI) were estimated for HT cases, age and sex adjusted to the 2000 US population. Multiple logistic regression was used to examine risk factors associated with HT.

Results: In 2015, there were 2301 ischemic strokes included in the analysis. Of these 104 (4.5%) had HT; 23 (22.1%) symptomatic, 55 (52.9%) asymptomatic and 26 (25%) unknown. Documented reasons for not receiving tPA in these patients were: time (71, 68.3%), anticoagulant use (1, 1.0%), other (18,17.3%) and unknown (14, 13.5%), which were not significantly different compared to those without HT. Only 29/104 (18.3%) had HT classified as PH-1 or PH-2. The age, sex and race-adjusted rate of HT was 9.8 (7.9, 11.6) per 100,000. The table shows rates of potential risk factors and the adjusted odds of developing HT. 90 day all-cause case fatality for patients with HT was significantly higher, 27.9% vs. 15.7%, p<0.0001.

Conclusion: We found that 4.5% of non-tPA treated IS patients had HT. These patients had more severe strokes, were more likely to have abnormal coagulation tests or anticoagulant use, and were more likely to die within 90 days. We also report the first population-based incidence rate of HT in non-tPA treated of 9.8/100,000, a rate similar to the incidence of SAH.

Abstract P716: Factors Associated With Functional Dependence at Hospital Discharge in Patients With Low NIHSS Strokes Who Do Not Receive Intravenous Alteplase

Introduction: Patients without prior functional deficits who suffer mild stroke (NIHSS <6) have a 20-30% likelihood of disability (mRS ≥2). Predictors of disability have been described mostly in clinical trials and single center registries. We identified variables associated with functional dependence (mRS ≥3) in mild stroke using a retrospective population-based sample.

Methods: Hospitalized strokes from the Greater Cincinnati Northern Kentucky Stroke Study were used. Included patients had an initial NIHSS <6 and baseline mRS 0, both extrapolated from chart review. To minimize the inclusion of patients with disabling symptoms, tPA treatment was excluded. Demographic and clinical characteristics were analyzed by discharge disability status. A multivariable logistic model with least absolute shrinkage and selection operator (lasso) regression analysis identified independent predictors of disability.

Results: Of 1268 ischemic strokes, 353 (28%) were functionally dependent at discharge. Increased baseline NIHSS was associated with worse outcome on the mRS. Leg, LOC questions, and sensation NIHSS subscores were the best predictors of outcome. Multivariable analysis identified age, race, hypertension, chronic kidney disease, heart failure, and post-stroke dysphagia as independently associated with discharge mRS ≥3.

Discussion: Our results agree with and complement the results of prior studies. They are not limited by inclusion/exclusion criteria or referral bias. Rather, our major limitation is the retrospective estimation of NIHSS and mRS based on physician descriptive documentation rather than direct score assessment. Our results may allow for modeling to better predict outcome which in turn can inform clinical decision making and trial design.

Abstract P121: Update on Regional Stroke Activation Trends During Covid-19 Mitigation

Background: The University of Cincinnati Stroke Team provides acute stroke care to the southwest Ohio, northern Kentucky, and southeast Indiana catchment area of ~2 million people and 30 healthcare facilities. We previously published a significant decline in stroke activations and reperfusion treatment (IV thrombolysis and EVT) rates following state announcements of COVID-19 mitigation measures. Here, we update these trends after state reopening guidelines.

Methods: We compared Stroke Team activations and reperfusion treatments logged in a prospectively collected database, comparing the same period in 2020 versus 2019. Kentucky and Ohio announced school and restaurant closures on March 12 and 13, respectively, followed by Indiana. A stepwise reopening of our tristate area started on May 1, 2020. We also compared trends in activations and treatment rates before (Weeks 1-10), during (Weeks 11-17), and after (Weeks 18-26) the lifting of COVID-19 mitigation efforts using the Poisson test, and graphically with segmented regression analysis.

Results: Compared to 2019, stroke team activations declined by 12% in 2020 (95% CI 7 - 16%; p<0.01). During 2020, an initial decline in stroke activations following COVID-19 mitigation announcements was followed by a 28% increase in activations after reopening (Weeks 18-26: 95% CI 15 - 42%; p<0.01). In contrast, compared to 2019, treatment rates were unchanged (0%, 95% CI -15 - 18%; p=1.00), including specifically IV thrombolysis and thrombectomy rates. Similarly, an initial decline in reperfusion treatments was followed by a 24% nonsignificant increase after reopening (95% CI -10 - 71%; p=0.19) in 2020.

Conclusion: The initial decline in stroke team activations during COVID-19 mitigation efforts was followed by an increase in activations after reopening. Hospital capacity and 911 services remained fully intact, suggesting that the reduction in activations were related to reduced presentation by patients for emergent stroke care.

Effect of COVID-19 on Emergent Stroke Care: A Regional Experience

BACKGROUND AND PURPOSE

Anecdotal evidence suggests that the coronavirus disease 2019 (COVID-19) pandemic mitigation efforts may inadvertently discourage patients from seeking treatment for stroke with resultant increased morbidity and mortality. Analysis of regional data, while hospital capacities for acute stroke care remained fully available, offers an opportunity to assess this. We report regional Stroke Team acute activations and reperfusion treatments during COVID-19 mitigation activities.

METHODS

Using case log data prospectively collected by a Stroke Team exclusively serving ≈2 million inhabitants and 30 healthcare facilities, we retrospectively reviewed volumes of consultations and reperfusion treatments for acute ischemic stroke. We compared volumes before and after announcements of COVID-19 mitigation measures and the prior calendar year.

RESULTS

Compared with the 10 weeks prior, stroke consultations declined by 39% (95% CI, 32%-46%) in the 5 weeks after announcement of statewide school and restaurant closures in Ohio, Kentucky, and Indiana. Results compared with the prior year and time trend analyses were consistent. Reperfusion treatments also appeared to decline by 31% (95% CI, 3%-51%), and specifically thrombolysis by 33% (95% CI, 4%-55%), but this finding had less precision.

CONCLUSIONS

Upon the announcement of measures to mitigate COVID-19, regional acute stroke consultations declined significantly. Reperfusion treatment rates, particularly thrombolysis, also appeared to decline qualitatively, and this finding requires further study. Urgent public education is necessary to mitigate a possible crisis of avoiding essential emergency care due to COVID-19.

Abstract TP440: Heart Failure is Associated With Elevated von Willebrand Factor (vWF) Antigen but not Factor VIII (FVIII) in Acute Ischemic Stroke (AIS)

Introduction: von Willebrand Factor (vWF) and factor VIII (FVIII) contribute to thrombosis and are important risk factors in acute ischemic stroke (AIS). Elevated vWF has been correlated with depressed left ventricular (LV) function, but has not been examined in a cohort of patients with AIS, particularly with regard to concurrent elevation in FVIII.

Hypothesis: We hypothesized that vWF is associated with HF and that combined elevation of vWF and FVIII would strengthen this association.

Methods: From our prospective stroke registry, AIS patients >18 years of age admitted from 09/2011 to 01/2015 were included if both FVIII and vWF were measured during hospitalization and an echocardiogram was performed. Comparisons were done between the following groups: patients with normal (-) vs. elevated (+) vWF, patients with (-) vs. (+) FVIII, and patients with (-) vs. (+) levels of both factors.

Results: Of 1,091 patients in the study period, 212 patients met inclusion criteria. In all groups, patients differed significantly according to history of DM. +vWF had higher frequency of female gender than -vWF, but did not differ according to any other demographic or baseline characteristics. +vWF patients had higher frequency of HF (p=0.007) and higher frequency of depressed LV function (p=0.028) compared to those with -vWF. vWF level correlated with HF (r=0.189, p=0.006) and reduced LV function (r=0.187, p=0.006). Similar findings were found with dual elevation, but we found no relationship between FVIII and HF. After adjustment for HTN, CAD, and DM, vWF remained an independent predictor of HF (OR 1.003, 95%CI 1.000-1.007, p=0.036). While we found no relationship between LV function and FVIII level, median vWF levels increased with decreasing LV function (p=0.027).

Conclusion: The results of our study suggest an association between HF and elevated vWF in the setting of AIS, irrespective of FVIII elevation. These results suggest the potential utility of vWF as an independent biomarker for heart failure in the AIS patient population.

Testosterone as a discriminative stimulus in male rats

Testosterone and other anabolic-androgenic steroids (AAS) are reinforcing in animals, as determined by conditioned place preference or self-administration. Most drugs of abuse produce subjective effects on mood and perception that initiate and maintain drug taking. Whether AAS have similar effects is not known. Food-restricted male Sprague-Dawley rats (n=9) were tested for their ability to discriminate an injection of testosterone from the β-cyclodextrin vehicle using a standard two-lever operant paradigm. In drug discrimination, animals use the subjective effects of drug or vehicle to select the appropriate lever to obtain food pellets under an FR10 schedule of reinforcement. All rats demonstrated vigorous responding for food (1415.1±76.1 responses/20 min) with 94.9% of responses on the active lever. For the first 30 days, rats received 1mg/kg testosterone sc 30 min before testing. On Day 14, one rat achieved the discrimination criteria of 9/10 consecutive days with >90% responses on the active lever and ≤5 responses on the inactive lever before the first reinforcement. Subsequently, rats were tested with testosterone at different doses (2, 7.5, 15 mg/kg at 30 min before testing) and times (2mg/kg at 30 or 60 min before testing), each for 20 days. One additional rat demonstrated successful discrimination at Day 54 with 2mg/kg testosterone 60 min before testing. The remaining 7 rats failed to discriminate testosterone within 110 days. When analyzed according to less-stringent standards, 4 additional rats met criteria for testosterone discrimination. However, continued performance was not stable. Thus, testosterone was unable to consistently support drug discrimination. We conclude that testosterone does not produce rapid interoceptive effects (NIH DA12843 to RIW).

MPTP Neurotoxicity and Testosterone Induce Dendritic Remodeling of Striatal Medium Spiny Neurons in the C57Bl/6 Mouse

Nigrostriatal damage is increased in males relative to females. While estrogen is neuroprotective in females, less is known about potential protective effects of testosterone in males. We determined if castration enhances neuronal injury to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Castrates or sham-castrated mice were sacrificed 1 week following injection of MPTP (4 × 20 mg/kg) or saline (n = 11-12/group). The right striatum was immunostained for tyrosine hydroxylase (TH). The left hemisphere was stained by Golgi Cox to quantify neuronal morphology in medium spiny neurons (MSNs) of the dorsolateral striatum. MPTP reduced TH, but there was no effect of castration and no interaction. For MSN dendritic morphology, MPTP decreased the highest branch order and increased spine density on 2nd-order dendrites. Castrated males had shorter 5th-order dendrites. However, there was no interaction between gonadal status and MPTP. Thus, castration and MPTP exert nonoverlapping effects on MSN morphology with castration acting on distal dendrites and MPTP acting proximally.

Sex differences in motor behavior in the MPTP mouse model of Parkinson's disease

Sex differences in Parkinson's disease (PD) have been reported in humans and rodent models, with a higher incidence in men and increased severity in male rodents. The current study examined sex differences and the effects of gonadal steroid hormones in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned mouse model of PD. Male (n=51) and female (n=50) mice were gonadectomized and received physiologic replacement with testosterone or estrogen (Experiment 1), or no hormones (Experiment 2). Two weeks later, mice received either MPTP (10 mg/kg per day for 5 days) or saline. Higher doses killed female mice. Mice were tested one week after MPTP for motor performance using rotarod, pole and gait tests. In hormone-treated mice, males significantly outperformed females in all three tests (p<0.05). Compared with females, males had a greater overall rotarod performance (ORP: 1317.1+/-98.3 vs. 988.1+/-95.6), descended a pole faster (7.1+/-0.6 vs. 9.6+/-0.7s), and had longer stride lengths (hindlimb 7.3+/-0.1 vs. 6.8+/-0.1cm). By contrast, ovariectomized female mice receiving saline outperformed castrated males on the rotarod (1296.6+/-83.3 vs. 811.2+/-113.7, p<0.05) and descended a pole faster (9.7+/-2.0 vs. 15.6+/-1.9s, p<0.05). MPTP significantly impaired ORP (p<0.05) in hormone-treated males (703.7+/-65.5) and females (432.8+/-88.6, p<0.05). After MPTP, stride length was selectively decreased in males (hindlimb 6.6+/-0.1 cm, p<0.05), and pole test performance was unimpaired in either sex. After gonadectomy, MPTP did not decrease motor performance in males (p>0.05) but significantly reduced ORP in females (975.9+/-110.3 vs. saline females, p<0.05). Our results show that small, chronic doses of MPTP produce subtle, sexually-dimorphic impairments in motor performance, but without a loss of tyrosine hydroxylase-positive neurons in the substantia nigra. In gonadectomized mice, this sex difference is reversed.

Cell proliferation and survival in the mating circuit of adult male hamsters: effects of testosterone and sexual behavior

The transient actions of gonadal steroids on the adult brain facilitate social behaviors, including reproduction. In male rodents, testosterone acts in the posterior medial amygdala (MeP) and medial preoptic area (MPOA) to promote mating. Adult neurogenesis occurs in both regions. The current study determined if testosterone and/or sexual behavior promote cell proliferation and survival in MeP and MPOA. Two experiments were conducted using the thymidine analog BrdU. First, gonad-intact and castrated male hamsters (n=6/group) were compared 24 h or 7 weeks after BrdU. In MeP, testosterone-stimulated cell proliferation 24 h after BrdU (intact: 22.8+/-3.9 cells/mm(2), castrate: 13.2+/-1.4 cells/mm(2)). Testosterone did not promote cell proliferation in MPOA. Seven weeks after BrdU, cell survival was sparse in both regions (MeP: 2.5+/-0.6 and MPOA: 1.7+/-0.2 cells/mm(2)), and was not enhanced by testosterone. In Experiment 2, gonad-intact sexually-experienced animals were mated weekly to determine if regular neural activation enhances cell survival 7 weeks after BrdU in MeP and MPOA. Weekly mating failed to increase cell survival in MeP (8.1+/-1.6 vs. 9.9+/-3.2 cells/mm(2)) or MPOA (3.9+/-0.7 vs. 3.4+/-0.3 cells/mm(2)). Furthermore, mating at the time of BrdU injection did not stimulate cell proliferation in MeP (8.9+/-1.7 vs. 8.1+/-1.6 cells/mm(2)) or MPOA (3.6+/-0.5 vs. 3.9+/-0.7 cells/mm(2)). Taken together, our results demonstrate a limited capacity for neurogenesis in the mating circuitry. Specifically, cell proliferation in MeP and MPOA are differentially influenced by testosterone, and the birth and survival of new cells in either region are not enhanced by reproductive activity.