Unaffected ex vivo clotting cascade by experimental hemostatic nanoparticles when introduced in the presence of recombinant tissue plasminogen activator

CONTEXT

Hemostatic nanoparticles (hNPs) have shown efficacy in decreasing intracerebral hemorrhage (ICH) in animal models and are suggested to be of use to counter tissue plasminogen activator (tPA)-induced acute ICH.

AIMS

The objective of this study was to test the ability of an hNP preparation to alter the clotting properties of blood exposed to tPA ex vivo.

MATERIALS AND METHODS

Fresh blood samples were obtained from normal male Sprague-Dawley rats (~300 g; n = 6) and prepared for coagulation assays by thromboelastography (TEG) methods. Samples were untreated, exposed to tPA, or exposed to tPA and then to hNP. TEG parameters included reaction time (R, time in minutes elapsed from test initiation to initial fibrin formation), coagulation time (K, time in minutes from R until initial clot formation), angle (α, a measure in degrees of the rate of clot formation), maximum amplitude (MA, the point when the clot reaches its MA in mm), lysis at 30 min after MA (LY30, %), and clot strength (G, dynes/cm2), an index of clot strength.

STATISTICAL ANALYSIS USED

Kruskal-Wallis test was employed to compare TEG parameters measured for untreated control samples versus those exposed to tPA and to compare tPA-exposed samples to samples treated with tPA + hNPs. Significances were inferred at P ≤ 0.05.

RESULTS

Compared to untreated samples, tPA-treated samples showed a trend toward decreased angle and G suggesting potentially clot formation rate and clot strength. The addition of hNP did not affect any of these or other measured indices.

CONCLUSIONS

The data demonstrated no hemostatic effects when the hNP was used in the presence of tPA. The lack of change in any of the TEG parameters measured in the present study may indicate limitations of the hNPs to reverse the thrombolytic cascade initiated by tPA.

Classification and Prediction of Post-Trauma Outcomes Related to PTSD Using Circadian Rhythm Changes Measured via Wrist-Worn Research Watch in a Large Longitudinal Cohort

Post-Traumatic Stress Disorder (PTSD) is a psychiatric condition resulting from threatening or horrifying events. We hypothesized that circadian rhythm changes, measured by a wrist-worn research watch are predictive of post-trauma outcomes.

APPROACH

1618 post-trauma patients were enrolled after admission to emergency departments (ED). Three standardized questionnaires were administered at week eight to measure post-trauma outcomes related to PTSD, sleep disturbance, and pain interference with daily life. Pulse activity and movement data were captured from a research watch for eight weeks. Standard and novel movement and cardiovascular metrics that reflect circadian rhythms were derived using this data. These features were used to train different classifiers to predict the three outcomes derived from week-eight surveys. Clinical surveys administered at ED were also used as features in the baseline models.

RESULTS

The highest cross-validated performance of research watch-based features was achieved for classifying participants with pain interference by a logistic regression model, with an area under the receiver operating characteristic curve (AUC) of 0.70. The ED survey-based model achieved an AUC of 0.77, and the fusion of research watch and ED survey metrics improved the AUC to 0.79.

SIGNIFICANCE

This work represents the first attempt to predict and classify post-trauma symptoms from passive wearable data using machine learning approaches that leverage the circadian desynchrony in a potential PTSD population.

Abstract P377: Real-Word Performance of Two Automated Software Platforms for Large-Vessel Occlusion Identification in Acute Ischemic Stroke Patients: A Single Center Experience

Background and purpose: Modern stroke treatment has been revolutionized by image-guided selection of patients for endovascular thrombectomy. Current automated platforms allow for real-time identification of large vessel occlusion and salvageable brain tissue. We had previously demonstrated that a “CTA for all” policy for stroke patients immediately upon arrival assists in the earlier identification of treatment candidates. We now sought to evaluate the performance of these platforms under this policy.

Methods: All patients that presented to Henry Ford Health System hospitals over a period of 6 weeks received CTA of the head and neck upon initial presentation. The images were processed with two automated software platforms. We prospectively collected processing times, large-vessel-occlusion alerts, performance warnings, and LVO density ratios. We compared these with the interpretations of board-certified radiologists, and analyzed the performance of each platform.

Results: 276 patients presented with stroke symptoms and received CT angiography upon presentation. Both platforms were able to image all stroke patients within their FDA-approved indications. Both platforms were noted to have comparable sensitivity, specificity, PPV and NPV, and excellent accuracy. The overall prevalence of LVO was extremely low (8/276). As a result, for both, NPV was much better than PPV because of the percentage of false positive results. Further ROC analysis, demonstrated an area under the ROC curve of 0.982, and overall model quality of 0.97. Optimal LVO density cutoff was <0.093 in order to maximize overall accuracy, or < 0.271, in order to maintain a sensitivity of 100% as an absolute priority (both significantly lower than the current threshold of <0.45).

Conclusions: Automated software platforms are an invaluable aid in the selection of patients for endovascular thrombectomy. Different LVO detection algorithmic thresholds may be necessary (and should be part of individual stroke center validation pathways) to avoid fatigue alert, and optimize test accuracy, when LVO prevalence is low. Stroke teams should be aware of the limitations of automated analysis and need for expert review.

Abstract P355: Real-Word Performance of Two Automated Software Platforms for Identification of Salvageable Tissue in Stroke Patients: A Single Center Experience

Background and purpose: Modern stroke treatment has been revolutionized by image-guided selection of patients for endovascular thrombectomy. Current automated platforms allow for real-time identification of large vessel occlusion and salvageable brain tissue. We sought to evaluate the performance of these platforms with regard to identification of infarcted and salvageable tissue.

Methods: We studied all patients that presented to Henry Ford Health System hospitals over a period of 6 weeks, received CT perfusion imaging of the brain upon initial presentation. The images were processed with two automated software platforms. We prospectively measured volumes of tissue with cerebral blood flow (CBF) < 30% of contralateral hemisphere, Tmax >6 secs, and hypoperfusion indices (defined as the ratio of volumes Tmax>10 secs and Tmax>6 secs). We compared the outputs of the two platforms and analyzed the performance of each platform.

Results: 66 scans were included in our study. Both platforms were able to image all stroke patients within their FDA-approved indications. With regard to all scans, both platforms were noted to demonstrate comparable CBF<30% volumes (6.32 ml. vs 4.97 ml, p=0.276), and hypoperfusion indices (0.278 vs 0.338, p=0.344). However, there was statistically significant discrepancy in the volumes of tissue with Tmax>6 secs (23.96 vs 14.18 ml, p=0.023). Analysis of a subset of 12 scans, with evidence of LVO or severe symptomatic stenosis on corresponding CTA, showed again comparable CBF<30% volumes (12.84 ml vs 13.67 ml, p=0.725), and hypoperfusion indices (0.344 vs 0.314, p=0.699). However, the Tmax>6 secs volume discrepancy was greater and still statistically significant (75.54 ml vs 39.58 ml, p=0.048)

Conclusions: Automated software platforms are an invaluable aid in the identification of salvageable tissue, and selection of patients for endovascular thrombectomy in the 6-24 hour window. However, the substantial difference in the identified volumes of hypoperfused tissue-at-risk may result in largely different clinical decisions and patient outcomes. Further validation efforts (and harmonization of algorithms) are required. Stroke teams should be aware of the limitations of automated analysis and need for expert review.

Abstract WP238: Safety and Outcomes of Stroke Mimics After Thrombolysis: A Single Center Experience

Background: Administration of intravenous (IV) t-PA for acute ischemic stroke (AIS) improves outcomes. The most dreaded complication is intracerebral hemorrhage (ICH). Some patients have symptoms that impersonate an AIS but are later found to have an alternate diagnosis; these are termed stroke mimics (SM). SM treated with IV t-PA are exposed to hemorrhagic complications without benefit.

Objectives: To describe the characteristics, safety, and outcomes of SM patients treated with t-PA under 4.5 hours.

Methods: We reviewed all patients hospitalized after IV t-PA treatment at a tertiary care hospital and primary stroke center from January 2008 through December 2011. SMs were determined by review of clinical and imaging findings. SM are described and compared to t-PA treated patients with AIS for demographics, ICH, bleeding complications, and outcomes.

Results: We identified 38 SM (12%) and 285 AIS (88%) t-PA treated patients. Compared to AIS, SM patients were younger (55.1 vs. 67.0 yrs, p<.001), more often women (68% vs.49%, p=.025), and reported a history of stroke more often (45% v 14%, p<.001). There were no differences in race, baseline stroke scale (9.4 v 10.9, p=.26), or onset to treatment time (164 min v 159 min, p=.63); 12 SM were in the 3-4.5 hour window. There were no ICHs or deaths in SM patients. There were two (5.2%) SM systemic hemorrhages; a femoral artery bleed post cardiac catheterization requiring transfusion, and an UGI bleed after a nasogastric tube not requiring transfusion. The average SM length of stay was 3.4 +/- 2.2 days. The mean discharge NIHSS score was 1.3 +/-2.5 in the SM v 4.6+/-5.7 in the AIS patients (p<.001). SM discharges were: home (84%), rehab center (12%), Nursing home 3%, and other (3%). The most common cause of SM was conversion disorder (47%) seizures (32 %) and migraine (8%).

Conclusion: SM are not uncommon. Treatment of SM with IV t-PA appears to be safe in this cohort. The most common etiologies of stroke mimics were conversion disorder, seizures, and migraine. These results are consistent with existing published data on use of IV t-PA in SMs. Until more specific diagnostics are available, suspected SM should not be a reason to withhold t-PA treatment.

Clinical Practice Guideline

Objective. Sudden hearing loss (SHL) is a frightening symptom that often prompts an urgent or emergent visit to a physician. This guideline provides evidence-based recommendations for the diagnosis, management, and follow-up of patients who present with SHL. The guideline primarily focuses on sudden sensorineural hearing loss (SSNHL) in adult patients (aged 18 and older). Prompt recognition and management of SSNHL may improve hearing recovery and patient quality of life (QOL). Sudden sensorineural hearing loss affects 5 to 20 per 100,000 population, with about 4000 new cases per year in the United States. This guideline is intended for all clinicians who diagnose or manage adult patients who present with SHL.

Purpose. The purpose of this guideline is to provide clinicians with evidence-based recommendations in evaluating patients with SHL, with particular emphasis on managing SSNHL. The panel recognized that patients enter the health care system with SHL as a nonspecific, primary complaint. Therefore, the initial recommendations of the guideline deal with efficiently distinguishing SSNHL from other causes of SHL at the time of presentation. By focusing on opportunities for quality improvement, the guideline should improve diagnostic accuracy, facilitate prompt intervention, decrease variations in management, reduce unnecessary tests and imaging procedures, and improve hearing and rehabilitative outcomes for affected patients.

Results. The panel made strong recommendations that clinicians should (1) distinguish sensorineural hearing loss from conductive hearing loss in a patient presenting with SHL; (2) educate patients with idiopathic sudden sensorineural hearing loss (ISSNHL) about the natural history of the condition, the benefits and risks of medical interventions, and the limitations of existing evidence regarding efficacy; and (3) counsel patients with incomplete recovery of hearing about the possible benefits of amplification and hearing-assistive technology and other supportive measures. The panel made recommendations that clinicians should (1) assess patients with presumptive SSNHL for bilateral SHL, recurrent episodes of SHL, or focal neurologic findings; (2) diagnose presumptive ISSNHL if audiometry confirms a 30-dB hearing loss at 3 consecutive frequencies and an underlying condition cannot be identified by history and physical examination; (3) evaluate patients with ISSNHL for retrocochlear pathology by obtaining magnetic resonance imaging, auditory brainstem response, or audiometric follow-up; (4) offer intratympanic steroid perfusion when patients have incomplete recovery from ISSNHL after failure of initial management; and (5) obtain follow-up audiometric evaluation within 6 months of diagnosis for patients with ISSNHL. The panel offered as options that clinicians may offer (1) corticosteroids as initial therapy to patients with ISSNHL and (2) hyperbaric oxygen therapy within 3 months of diagnosis of ISSNHL. The panel made a recommendation against clinicians routinely prescribing antivirals, thrombolytics, vasodilators, vasoactive substances, or antioxidants to patients with ISSNHL. The panel made strong recommendations against clinicians (1) ordering computerized tomography of the head/brain in the initial evaluation of a patient with presumptive SSNHL and (2) obtaining routine laboratory tests in patients with ISSNHL.

Sildenafil treatment of subacute ischemic stroke: a safety study at 25-mg daily for 2 weeks

BACKGROUND

In several animal studies of young and aged rats with ischemic stroke, treatment with sildenafil improved functional outcomes compared with placebo. We conducted a safety study of sildenafil (25 mg daily for 2 weeks) shortly after ischemic stroke onset.

METHODS

We recruited patients aged 18 to 80 years with ischemic stroke, National Institutes of Health stroke scale (NIHSS) score 2 to 21, between days 2 and 9 after symptom onset. Patients were treated with sildenafil for 2 weeks (25 mg daily). The primary outcome measure was the adverse occurrence of any of the following during the treatment period: stroke worsening, new stroke, myocardial infarction, vision loss, hearing loss, or death from any cause. Secondary outcome measures were NIHSS score, Barthel indices, and modified Rankin score at 90 days.

RESULTS

Twelve patients were recruited. Mean age was 57 years, 5 were female, and median NIHSS score at entry was 9.5 (range 2-20). The primary outcome measure occurred in one patient (sudden death). Another patient committed suicide 2 months after study entry (and 6 weeks after treatment with sildenafil had been completed). Among the 10 survivors, at 90 days, median NIHSS score was 2 (range 0-12), median Barthel index was 95 (range 15-100), and median modified Rankin score was 1.5 (range 0-5).

CONCLUSIONS

Sildenafil (25 mg daily for 2 weeks) appeared to be safe in this group of patients with mild to moderately severe stroke. Further studies of higher doses will be tested.

Centenarian stroke treated with tissue-type plasminogen activator

BACKGROUND

Elderly patients with acute ischemic stroke often do worse than younger counterparts independent of thrombolytic therapy. Further, tissue-type plasminogen activator, (t-PA) is frequently withheld from the very old. This may be the result of comorbid conditions prohibiting its use or possibly the fear of causing more harm than good. We present a case of a 100-year-old woman who was treated with t-PA for acute ischemic stroke with rapid resolution of symptoms.

CASE DESCRIPTION

A 100-year-old woman presented to the emergency department with slurred speech, right hemiparesis and right hemisensory loss. Computed tomography revealed neither hemorrhage nor early ischemic changes. Intravenous t-PA was administered at 0.9 mg/kg 3 min prior to the 3-hour limit. She improved rapidly (NIHSS from 12 on admission to 4 at 1 month) and was discharged to the care of her family after 4 hospital days.

CONCLUSION

Intravenous thrombolysis may be beneficial in the very elderly and should be considered in any eligible elderly patients with acute ischemic stroke, with a risk/benefit analysis individualized to each case.

Lack of clinical significance of early ischemic changes on computed tomography in acute stroke

CONTEXT

The prevalence and clinical significance of early ischemic changes (EICs) on baseline computed tomography (CT) scan of the head obtained within 3 hours of ischemic stroke are not established.

OBJECTIVE

To determine the frequency and significance of EIC on baseline head CT scans in the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA (recombinant tissue plasminogen activator) Stroke Trial.

DESIGN AND SETTING

The original study, a randomized controlled trial, took place from January 1991 through October 1994 at 43 sites, during which CT images were obtained within 3 hours of symptom onset and prior to the initiation of rt-PA or placebo. For the current analysis, detailed reevaluation was undertaken after October 1994 of all baseline head CT scans with clinical data available pretreatment (blinded to treatment arm).

PATIENTS

Of 624 patients enrolled in the trial, baseline CT scans were retrieved and reviewed for 616 (99%).

MAIN OUTCOME MEASURES

Frequency of EICs on baseline CT scans; association of EIC with other baseline variables; effect of EICs on deterioration at 24 hours (>/=4 points increase from the baseline National Institutes of Health Stroke Scale [NIHSS] score); clinical outcome (measured by 4 clinical scales) at 3 months, CT lesion volume at 3 months, death at 90 days; and symptomatic intracranial hemorrhage (ICH) within 36 hours of treatment.

RESULTS

The prevalence of EIC on baseline CT in the combined rt-PA and placebo groups was 31% (n = 194). The EIC was significantly associated with baseline NIHSS score (rho = 0.23; P<.001) and time from stroke onset to baseline CT scan (rho = 0.11; P =.007). After adjusting for baseline variables, there was no EIC x treatment interaction detected for any clinical outcome, including deterioration at 24 hours, 4 clinical scales, lesion volume, and death at 90 days (P>/=.25), implying that EIC is unlikely to affect response to rt-PA treatment. After adjusting for NIHSS score (an independent predictor of ICH), no EIC association with symptomatic ICH at 36 hours was detected in the group treated with rt-PA (P>/=.22).

CONCLUSIONS

Our analysis suggests that EICs are prevalent within 3 hours of stroke onset and correlate with stroke severity. However, EICs are not independently associated with increased risk of adverse outcome after rt-PA treatment. Patients treated with rt-PA did better whether or not they had EICs, suggesting that EICs on CT scan are not critical to the decision to treat otherwise eligible patients with rt-PA within 3 hours of stroke onset.

Outcome of stroke patients without angiographically revealed arterial occlusion within four hours of symptom onset

BACKGROUND AND PURPOSE

Follow-up imaging data from stroke patients without angiographically apparent arterial occlusions at symptom onset are lacking. We reviewed our Emergency Management of Stroke (EMS) trial experience to determine the clinical and imaging outcomes of patients with ischemic stroke who showed no arterial occlusion on angiograms obtained within 4 hours of symptom onset.

METHODS

All patients in this report were participants in the EMS trial that was designed to address the safety and potential efficacy of combined IV and intraarterial thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA) in patients with acute ischemic stroke.

RESULTS

Thirty-five patients were randomized to receive either IV rt-PA (n = 17) or placebo (n = 18), followed by cerebral angiography. No symptomatic arterial occlusion was evident in 10 (29%) of the 34 patients. Eight (80%) of 10 patients without angiographically apparent clot within 4 hours of symptom onset had a new cerebral infarction confirmed on follow-up brain imaging. The median 72-hour infarction volume was 2.4 cc (range, 1-30 cc). Four of the 10 "no-clot" patients had a favorable 3-month outcome as assessed by Barthel Index (score, 95 or 100) and modified Rankin Scale (score, 0 or 1). The six remaining patients had 3-month Rankin Scale scores of 1 (Barthel of 90), 2, 3, 4, or 5.

CONCLUSION

Acute ischemic stroke patients with a neurologic deficit but a negative angiogram during the first 4 hours after symptom onset usually develop image-documented cerebral infarction, and approximately half suffer from long-term functional disability. The two most likely explanations for negative angiograms are very early irreversible ischemic damage despite recanalization or ongoing ischemia secondary to clot in non-visible penetrating arterioles or in the microvasculature.

Early stroke treatment associated with better outcome: the NINDS rt-PA stroke study

BACKGROUND

The National Institute of Neurological Disorders and Stroke (NINDS) rt-PA Stroke Study showed a similar percentage of intracranial hemorrhage and good outcome in patients 3 months after stroke treatment given 0 to 90 minutes and 91 to 180 minutes after stroke onset. At 24 hours after stroke onset more patients treated 0 to 90 compared to 91 to 180 minutes after stroke onset had improved by four or more points on the NIH Stroke Scale (NIHSS). The authors performed further analyses to characterize the relationship of onset-to-treatment time (OTT) to outcome at 3 months, early improvement at 24 hours, and intracranial hemorrhage within 36 hours.

METHODS

Univariate analyses identified potentially confounding variables associated with OTT that could mask an OTT-treatment interaction. Tests for OTT-treatment interactions adjusting for potential masking confounders were performed. An OTT-treatment interaction was considered significant if p < or = 0.10, implying that treatment effectiveness was related to OTT.

RESULTS

For 24-hour improvement, there were no masking confounders identified and there was an OTT-treatment interaction (p = 0.08). For 3-month favorable outcome, the NIHSS met criteria for a masking confounder. After adjusting for NIHSS as a covariate, an OTT-treatment interaction was detected (p = 0.09): the adjusted OR (95% CI) for a favorable 3-month outcome associated with recombinant tissue-type plasminogen activator (rt-PA) was 2.11 (1.33 to 3.35) in the 0 to 90 minute stratum and 1.69 (1.09 to 2.62) in the 91 to 180 minute stratum. In the group treated with rt-PA, after adjusting for baseline NIHSS, an effect of OTT on the occurrence of intracranial hemorrhage was not detected.

CONCLUSIONS

If the NINDS rt-PA Stroke Trial treatment protocol is followed, this analysis suggests that patients treated 0 to 90 minutes from stroke onset with rt-PA have an increased odds of improvement at 24 hours and favorable 3-month outcome compared to patients treated later than 90 minutes. No effect of OTT on intracranial hemorrhage was detected within the group treated with rt-PA, possibly due to low power.

Combined intravenous and intra-arterial r-TPA versus intra-arterial therapy of acute ischemic stroke: Emergency Management of Stroke (EMS) Bridging Trial

BACKGROUND AND PURPOSE

The purpose of this study was to test the feasibility, efficacy, and safety of combined intravenous (IV) and local intra-arterial (IA) recombinant tissue plasminogen activator (r-TPA) therapy for stroke within 3 hours of onset of symptoms.

METHODS

This was a double-blind, randomized, placebo-controlled multi-center Phase I study of IV r-TPA or IV placebo followed by immediate cerebral arteriography and local IA administration of r-TPA by means of a microcatheter. Treatment activity was assessed by improvement on the National Institutes of Health Stroke Scale Score (NIHSSS) at 7 to 10 days. The Barthel Index, modified Rankin Scale, and the Glasgow Outcome Scale measured 3-month functional outcome. Arterial recanalization rates and their relation to total r-TPA dose and time to lysis were measured. Rates of life-threatening bleeding, intracerebral hemorrhage (ICH), or other bleeding complications assessed safety.

RESULTS

Thirty-five patients were randomly assigned, 17 into the IV/IA group and 18 into the placebo/IA group. There was no difference in the 7- to 10-day or the 3-month outcomes, although there were more deaths in the IV/IA group. Clot was found in 22 of 34 patients. Recanalization was better (P=0. 03) in the IV/IA group with TIMI 3 flow in 6 of 11 IV/IA patients versus 1 of 10 placebo/IA patients and correlated to the total dose of r-TPA (P=0.05). There was no difference in the median treatment intervals from time of onset to IV treatment (2.6 vs 2.7 hours), arteriography (3.3 vs 3.0 hours), or clot lysis (6.3 vs 5.7 hours) between the IV/IA and placebo/IA groups, respectively. A direct relation between NIHSSS and the likelihood of the presence of a clot was identified. Eight ICHs occurred; all were hemorrhagic infarctions. There were no parenchymal hematomas. Symptomatic ICH within 24 hours occurred in 1 placebo/IA patient only. Beyond 24 hours, symptomatic ICH occurred in 2 IV/IA patients only. Life-threatening bleeding complications occurred in 2 patients, both in the IV/IA group. Moderate to severe bleeding complications occurred in 2 IV/IA patients and 1 placebo/IA patient.

CONCLUSIONS

This pilot study demonstrates combined IV/IA treatment is feasible and provides better recanalization, although it was not associated with improved clinical outcomes. The presence of thrombus on initial arteriography was directly related to the baseline NIHSSS. This approach is technically feasible. The numbers of symptomatic ICH were similar between the 2 groups, which suggests that this approach may be safe. Further study is needed to determine the safety and effectiveness of this new method of treatment. Such studies should address not only efficacy and safety but also the cost-benefit ratio and quality of life, given the major investment in time, personnel, and equipment required by combined IV and IA techniques.

Agreement and variability in the interpretation of early CT changes in stroke patients qualifying for intravenous rtPA therapy

BACKGROUND AND PURPOSE

Ischemic changes identified on CT scans performed in the first few hours after stroke onset, which are thought to possibly represent early cytotoxic edema and development of irreversible injury, may have important implications for subsequent treatment. However, insecurity and conflicting data exist over the ability of clinicians to correctly recognize and interpret these changes. We performed a detailed review of selected baseline CT scans from the NINDS rt-PA Stroke Trial to test agreement among experienced stroke specialists and other physicians on the presence of early CT ischemic changes.

METHODS

Seventy baseline CT scans from the NINDS Stroke Trial were read and classified for the presence or absence of various early findings of ischemia by 16 individuals, including NINDS trial investigators, other neurologists, other emergency medicine physicians, and radiology or stroke fellows. CT scans included normal scans and scans from patients who later developed symptomatic intracranial hemorrhage, as well as scans on which the NINDS rt-PA Stroke Trial neuroradiologist identified clear-cut early CT changes. For each CT finding, kappa-statistics were used to assess the proportion of agreement beyond chance.

RESULTS

kappa-Values (95% confidence interval [CI]) ranged from 0.20 (-0.20, 0.61) (fair agreement) to 0.41 (0.37, 0.45) (moderate agreement) among the 16 viewers, and the kappa-value was only 0.39 (0.29, 0.49) (fair) in answer to the question "do early CT changes involve more than one third of the MCA [middle cerebral artery] territory?" There was substantial variability within each specialty group and between groups. kappa-Values were only fair to moderate even among physicians experienced in selecting and treating acute stroke patients with rtPA. Observed agreement ranged from 68% to 85%. Physicians agreed on the finding of early CT changes involving >33% of the MCA territory 77% of the time, although the kappa-value of 0.39 suggested only moderate agreement beyond chance.

CONCLUSIONS

There is considerable lack of agreement, even among experienced clinicians, in recognizing and quantifying early CT changes. Improved methods of recognizing and quantifying early ischemic brain damage are needed.

Effects of tissue plasminogen activator for acute ischemic stroke at one year. National Institute of Neurological Disorders and Stroke Recombinant Tissue Plasminogen Activator Stroke Study Group

BACKGROUND

In 1995, the two-part National Institute of Neurological Disorders and Stroke (NINDS) Recombinant Tissue Plasminogen Activator Stroke Trial found that patients who were treated with tissue plasminogen activator (t-PA) within three hours after the onset of symptoms of acute ischemic stroke were at least 30 percent more likely than patients given placebo to have minimal or no disability three months after the stroke. It was unknown, however, whether the benefit would be sustained for longer periods.

METHODS

In the NINDS Trial, a total of 624 patients with stroke were randomly assigned to receive either t-PA or placebo. We collected outcome data over a period of 12 months after the occurrence of stroke. The primary outcome measure was a "favorable outcome," defined as minimal or no disability as measured by the Barthel index, the modified Rankin Scale, and the Glasgow Outcome Scale. We assessed the treatment effect using a global statistic.

RESULTS

Using an intention-to-treat analysis for the combined results of the two parts of the trial at 6 months and 12 months, we found that the global statistic favored the t-PA group (odds ratio for a favorable outcome at 6 months, 1.7; 95 percent confidence interval, 1.3 to 2.3; odds ratio at 12 months, 95 percent confidence interval, 1.7; 1.2 to 2.3). The patients treated with t-PA were at least 30 percent more likely to have minimal or no disability at 12 months than were the placebo-treated patients (absolute increase in the proportion with a favorable outcome, 11 to 13 percentage points). There was no significant difference in mortality at 12 months between the t-PA group and the placebo group (24 percent vs. 28 percent, P=0.29). There was no interaction between the type of stroke identified at base line and treatment with respect to the long-term response. The rate of recurrent stroke at 12 months was similar in the two groups.

CONCLUSIONS

During 12 months of follow-up, the patients with acute ischemic stroke who were treated with t-PA within three hours after the onset of symptoms were more likely to have minimal or no disability, than the patients given placebo. These results indicate a sustained benefit of t-PA for such patients.

Simultaneous radial, femoral, and aortic arterial pressures during human cardiopulmonary resuscitation

OBJECTIVE

To examine the validity of interchanging arterial sites and their responses to graded doses of epinephrine during human cardiopulmonary resuscitation (CPR).

DESIGN

Consecutive case series.

SETTING

Large, urban Emergency Department.

PATIENTS

Adult, normothermic, nonhemorrhagic cardiac arrest patients.

INTERVENTIONS

While receiving advanced cardiac life support, patients received right atrial (n = 40), aortic (n = 40), radial (n = 40), and femoral (n = 17) artery catheters. Pressures were measured simultaneously at baseline, after 0.01 mg/kg and 0.2 mg/kg of epinephrine.

MEASUREMENTS AND MAIN RESULTS

The mean aortic compression-phase pressure was 9.3 +/- 10 (SD), 8.1 +/- 11, and 4.4 +/- 9.5 mm Hg higher than radial artery pressure at baseline, after 0.01 mg/kg, and 0.2 mg/kg of epinephrine, respectively (all statistically significant). When compared with the femoral artery at the same time points, the mean aortic compression-phase pressure was also 3.0 +/- 6.8, 1.9 +/- 8, and 0.6 +/- 7.7 mm Hg higher, respectively (none statistically significant). The aortic relaxation-phase pressure was 1.3 +/- 3.6, 1.1 +/- 3.8, and 1.6 +/- 2.5 mm Hg lower than the radial artery at baseline, after 0.01 mg/kg and 0.2 mg/kg of epinephrine, respectively (all statistically significant). When compared with the femoral artery at the same time points, the aortic relaxation-phase pressure was 0.6 +/- 2.0, 0.3 +/- 3.3, and 0.3 +/- 2.4 mm Hg lower, respectively (none statistically significant).

CONCLUSIONS

Radial artery relaxation-phase pressure, although statistically higher, correlated with aortic relaxation-phase pressure. Femoral artery relaxation-phase pressure was not statistically different from aortic relaxation-phase pressure. Aortic pressure was statistically higher and had a lower correlation with radial artery pressures during compression phase. The aortic to radial artery and aortic to femoral artery compression-phase gradients abated with increasing doses of epinephrine therapy. Caution must be used when substituting compression-phase pressure obtained at radial or femoral artery sites for aortic pressure during human CPR. Coronary artery perfusion pressures obtained with radial and femoral arteries correlate with aortic pressure when measuring the response to vasopressor therapy during CPR when an interpretable waveform exists.

Angioedema related to angiotensin-converting enzyme inhibitors

Angioedema is a disorder characterized by well-demarcated nonpitting edema involving the tongue, floor of the mouth, larynx, lips, and face. This condition can progress to upper airway obstruction and death. Angiotensin-converting enzyme inhibitors (ACEIs), relatively new antihypertensive agents, act by blocking the formation of angiotensin II, a potent vasoconstrictor and stimulator of aldosterone formation. ACEIs also retard the breakdown of bradykinin, a potent vasodilator, which may lead to the edema seen in nonhereditary angioedema. These ACEIs include enalapril, captopril, lisinopril, saralasin acetate, and a combination of ACEI with diuretics (for example, Capozide). From August 1987 to January 1989, we treated six patients with a nonhereditary form of angioedema related to ingestion of angiotensin-converting enzyme inhibitors. Symptoms developed in all patients within 12 hours after their initial dose of an ACEI. They presented with shortness of breath and dysphagia associated with tongue and floor of the mouth edema. Two of the six required intubation and monitoring in the surgical intensive care unit for 36 to 48 hours. Three required supportive treatment and observation in an intermediate care unit, and one received supportive care in the clinic and was discharged the same day. Specifically, treatment consisted of cessation of inciting agent, steroids, antihistamines, and epinephrine, if not otherwise contraindicated. Assays of C1 esterase inhibitor levels and C4 were normal in all six patients; this was important in order to rule out hereditary forms of angioedema. These cases will be discussed, including a review of the literature, methods of diagnosis, pathophysiology, and treatment of angioedema.

Dissecting cellulitis of the scalp

Dissecting cellulitis of the scalp or perifolliculitis capitis abscedens et suffodiens is a rare, chronic, progressive, suppurative disease of the scalp of unknown etiology. It is characterized by painful nodules, purulent drainage, burrowing interconnecting abscesses, and cicatricial alopecia. The pathogenesis is unknown, although it is probably related to follicular occlusion, secondary infection, and deep inflammation. Black men in their second to fourth decade are predominantly affected. Treatment varies from systemic antibiotics to incision and drainage, x-ray epilation of the affected areas, systemic steroid administration, and surgical excision. Our experience with four patients with extensive scalp disease is presented. Wide excision of the affected areas and splitthickness skin graft are favored as our treatment of choice.