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Background and Purpose: We investigated the prevalence, awareness, and control of vascular risk factors (VRFs) and the use of antithrombotic and statin agents in HCHS (Hispanic Community Health Study)/SOL (Study of Latinos) participants with self-reported history of stroke or transient ischemic attack. Methods: Sociodemographic characteristics, medications, and prevalence of different VRFs were recorded. VRF diagnoses and goals were based on the recommendations of professional organizations. Factors associated with optimal VRF control and use of antithrombotic and statin agents were investigated using multivariate logistic regression. Results: The analysis included 404 participants (39% men). The prevalences of hypertension, dyslipidemia, and diabetes were 59%, 65%, and 39%, respectively. Among those who met the diagnostic criteria for these diagnoses, the frequencies of awareness were 90%, 75%, and 83%, respectively. In participants who were aware of their VRFs, the prevalences of controlled hypertension, dyslipidemia, and diabetes were 46%, 32%, and 54%. Approximately 46% of the participants were on antithrombotics, 39% on statins, and 26% on both. Only 38% of those with atrial fibrillation received anticoagulation. In multivariate analyses adjusted for baseline sociodemographic characteristics, older age was associated with uncontrolled hypertension and diabetes. Residing in the United States for ≥10 years and born in the United States were associated with uncontrolled diabetes, female sex with uncontrolled dyslipidemia, and lack of health insurance with decreased use of statins and hyperlipidemia. Conclusions: Hispanic/Latino adults in the United States have high prevalence and awareness of VRFs but low adherence to secondary stroke prevention strategies. Older adults, women, and uninsured people are vulnerable groups that may benefit from targeted interventions. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02060344.

Introduction: Prior evidence suggests that treatment outcomes after ischemic stroke differ based on racial background. For example, two studies that queried the National Inpatient Sample (NIS) found that White patients were more likely to be discharged home compared to non-White patients after treatment with mechanical thrombectomy or IV tPA. Although these database studies provide the advantage of substantial patient numbers, the NIS is an inpatient administrative dataset lacking stroke-specific outcomes such as modified Rankin Score (mRS) and follow-up data. Nevertheless, a relationship between race and clinical outcome after thrombectomy is suggested. Methods: We utilized the NeuroVascular Quality Initiative-Quality Outcomes Database (NVQI-QOD) to collect demographic data, clinical information, and outcome measures on ischemic stroke patients treated with mechanical thrombectomy. Univariate and multivariate analysis was conducted to evaluate the relationship between race and outcomes such as mRS at discharge (0-2 vs. 3-6), discharge disposition, and 90-day mRS (0-2 vs. 3-6). Race was included in multivariate modeling as it was our predictor variable of interest. P Results: A total of 3,597 patients were included. Of the entire cohort, 15.8% of patients were Black. On univariate analysis, Black race was significantly associated with younger age at treatment, CHF, hypertension, diabetes, prior stroke, being a current smoker, and higher baseline NIHSS (16.4 for Black compared to 15.8 for non-Black, p=0.044). Non-Black race was significantly associated with atrial fibrillation and hyperlipidemia at baseline. On both univariate and multivariate analysis, Black race was not significantly associated with discharge mRS, discharge to home, or 90-day mRS (p>0.3 for all). Conclusions: In conclusion, though Black race seems to be associated with several comorbidities prior to ischemic stroke, we did not find a significant association between Black race and clinical outcome after mechanical thrombectomy.

Background and Purpose: The role of regional hypoperfusion as a contributor to stroke risk in atherosclerotic vertebrobasilar disease has recently been confirmed by the observational VERiTAS (Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke) Study. We examined the stability of hemodynamic status over time and its relationship to stroke risk in patients from this prospective cohort. Methods: VERiTAS enrolled patients with recently symptomatic ≥50% atherosclerotic stenosis/occlusion of vertebral and/or basilar arteries. Large vessel flow in the vertebrobasilar territory was assessed using quantitative magnetic resonance angiography, and patients were designated as low or normal flow based on distal territory regional flow, incorporating collateral capacity. Patients underwent standard medical management and follow-up for primary outcome event of vertebrobasilar territory stroke. Quantitative magnetic resonance angiography imaging was repeated at 6, 12, and 24 months. Flow status over time was examined relative to baseline and relative to subsequent stroke risk using a cause-specific proportional hazard model, with flow status treated as a time-varying covariate. Mean blood pressure was examined to assess for association with changes in flow status. Results: Over 19±8 months of follow-up, 132 follow-up quantitative magnetic resonance angiography studies were performed in 58 of the 72 enrolled patients. Of the 13 patients with serial imaging who had low flow at baseline, 7 (54%) had improvement to normal flow at the last follow-up. Of the 45 patients who had normal flow at baseline, 3 (7%) converted to low flow at the last follow-up. The mean blood pressure did not differ in patients with or without changes in flow status. The time-varying flow status remained a strong predictor of subsequent stroke (hazard ratio, 10.3 [95% CI, 2.2–48.7]). Conclusions: There is potential both for improvement and worsening of hemodynamics in patients with atherosclerotic vertebrobasilar disease. Flow status, both at baseline and over time, is a risk factor for subsequent stroke, thus serving as an important prognostic marker. Registration: URL: https://clinicaltrials.gov . Unique identifier: NCT00590980.

Background and Purpose— The VERiTAS (Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke) study demonstrated posterior circulation distal flow status, determined by quantitative magnetic resonance angiography, is a robust predictor of vertebrobasilar stroke risk in patients with symptomatic atherosclerotic vertebrobasilar disease. Flow-compromised high-risk patients may benefit from flow-restoring endovascular procedures, such as submaximal angioplasty. In this study, we examine the cost-effectiveness of quantitative magnetic resonance angiography screening to identify patients who may benefit from submaximal angioplasty to restore vertebrobasilar flow. Methods— A Markov model was created comparing a no screening strategy with standard medical management alone and a screening strategy involving quantitative magnetic resonance angiography imaging and submaximal angioplasty for treatable patients with low vertebrobasilar flow for a 30-year time horizon. Outcomes included quality-adjusted life years (QALY) and lifetime costs. Rates of stroke and death were obtained from VERiTAS data, and disability rates and costs were derived from VERiTAS and the literature. A sensitivity analysis was performed with periprocedural stroke rate from angioplasty the primary variable of interest. Results— At a 6% periprocedural stroke risk, the screening strategy saved an average of 0.364 QALYs per patient and a lifetime cost savings of $7312 versus the no screening strategy. Among patients with low flow suitable for intervention, the benefit was substantially higher, averaging 1.485 QALYs saved and lifetime cost savings of $21 294. Across the entire cohort, QALY savings were observed at the end of the first year and economic savings at year 6. The benefit of screening declined at higher periprocedural risk. Conclusions— Quantitative magnetic resonance angiography screening and submaximal angioplasty with 6% periprocedural risk in suitable patients are cost effective both in terms of QALY and lifetime costs for patients with symptomatic vertebrobasilar occlusive disease. With potential health and economic savings, a clinical trial examining the periprocedural risk of submaximal angioplasty is warranted. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00590980.

Background and Purpose— Cerebral hypoperfusion symptoms (defined as symptoms related to change in position, effort or exertion, or recent change in antihypertensive medication) have been used in stroke studies as a surrogate for detecting hemodynamic compromise. However, the validity of these symptoms in identifying flow compromise in patients has not been well established. We examined whether hypoperfusion symptoms correlated with quantitative measurements of flow compromise in the prospective, observational VERiTAS study (Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke). Methods— VERiTAS enrolled patients with recent vertebrobasilar transient ischemic attack or stroke and ≥50% atherosclerotic stenosis or occlusion in vertebral or basilar arteries. Hemodynamic status using vertebrobasilar large vessel flow was measured using quantitative magnetic resonance angiography, and patients were designated as low, borderline, or normal flow based on distal territory regional flow, incorporating collateral capacity. The presence of qualifying event hypoperfusion symptoms was assessed relative to the quantitatively determined flow status (normal versus borderline/low) and also examined as a predictor of subsequent stroke risk. Results— Of the 72 enrolled subjects, 66 had data on hypoperfusion symptoms available. On initial quantitative magnetic resonance angiography designation, 43 subjects were designated as normal flow versus 23 subjects designated as low flow (n=16) or borderline flow (n=7). Of these, 5 (11.6%) normal flow and 3 (13.0%) low/borderline flow subjects reported at least one qualifying event hypoperfusion symptom ( P =0.99, Fisher exact test). Hypoperfusion symptoms had a positive predictive value of 37.5% and negative predictive value of 65.5% for low/borderline flow status. Compared with flow status, which strongly predicted subsequent stroke risk, hypoperfusion symptoms were not associated with stroke outcome ( P =0.87, log-rank test). Conclusions— These results suggest that hypoperfusion symptoms alone correlate poorly with actual hemodynamic compromise as assessed by quantitative magnetic resonance angiography and subsequent stroke risk in vertebrobasilar disease, and are not a reliable surrogate for flow measurement. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT00590980.

Background: Population studies showed that Hispanic/Latino adults have elevated rates of uncontrolled cardiovascular risk factors (CVRFs) with noticeable sex-specific variations . We investigated prevalence of CVRFs and the use of American Heart Association (AHA) secondary stroke prevention strategies in Hispanics/Latinos in the United States. Methods: Data from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) were used to examine sociodemographic characteristics, use of antithrombotic agents and statins, and treatment of CVRFs in persons with a history of stroke or transient ischemic attack (TIA). CVRFs were categorized as “controlled” if the CVRF met the goals defined by the AHA irrespective of whether the subject was on treatment for it or not; and “unaware” if the participant denied having a CVRF but met the diagnostic criteria for it. Differences between men and women were tested using ANOVA test and Pearson’s χ 2 . Factors associated with adherence to AHA recommendations were investigated using logistic regression. Results: These analyses included 404 individuals with history of stroke/TIA (men=159; women=245). Women were slightly older than men (55.1±1.5 vs. 54.1±1.6 years; p10 years in the US were associated with uncontrolled HC and DM, respectively. Conclusion: Hispanics/Latinos with stroke have elevated rates of awareness but suboptimal use of AHA secondary stroke prevention strategies. Older persons and women are vulnerable groups that may benefit from targeted interventions.

Introduction: Hypoperfusion symptoms, defined as symptoms related to change in position (i.e. supine to seated), effort or exertion, or recent change in antihypertensive medication have been used in stroke studies as a surrogate for detecting hemodynamic compromise. However, the validity of these symptoms in identifying flow compromise in patients has not been well established. We examined whether hypoperfusion symptoms correlated with quantitative evaluation of flow compromise in the prospective observational Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS) study. Methods: VERiTAS enrolled patients with recent vertebrobasilar TIA or stroke and ≥50% atherosclerotic stenosis or occlusion in vertebral and/or basilar arteries. Hemodynamic status using large vessel flow in the vertebrobasilar territory was measured using quantitative magnetic resonance angiography (QMRA), and patients were designated as low, borderline or normal flow based on distal territory regional flow, incorporating collateral capacity, as previously reported. The presence of qualifying event hypoperfusion symptoms was assessed relative to the quantitatively determined flow status (normal vs borderline/low), and also examined as a predictor of subsequent stroke risk. Results: Of the 72 enrolled subjects, 66 had data on hypoperfusion symptoms available. On initial QMRA designation, 43 subjects were designated as normal flow vs. 23 subjects designated as low flow (n=16) or borderline (n=7). Of these, 5 (11.6%) normal flow and 3 (13.0%) low/borderline flow subjects reported at least one qualifying event hypoperfusion symptom (p=0.99, Fisher’s exact test). Hypoperfusion symptoms had a positive predictive value of 37.5% and negative predictive value of 65.5% for low/borderline flow status. Compared to flow status, which strongly predicted subsequent stroke risk, hypoperfusion symptoms were not associated with stroke outcome (p=0.87, log rank test). Conclusions: These results suggest that hypoperfusion symptoms alone correlate poorly with actual hemodynamic compromise, and subsequent stroke risk in vertebrobasilar disease, and are not a reliable surrogate for flow measurement.

Objectives: Patients with symptomatic atherosclerotic vertebrobasilar disease are at high risk for recurrent stroke and we have demonstrated that distal flow status is independently associated with this risk. Our aim was to assess the mechanism of recurrent strokes in these patients related to their distal flow status. Methods: Patients with symptomatic atherosclerotic vertebrobasilar disease were enrolled in a prospective longitudinal cohort study (VERiTAS) with a median follow-up of 23 months. Large-vessel flow in the posterior circulation distal to the stenosis and/or occlusion was measured on quantitative MR angiography and dichotomized into normal or low flow. Three observers, who were blinded to the distal flow status, independently reviewed the imaging done at the time of the recurrent stroke to classify the most likely stroke mechanism. Results: Ten out of 72 enrolled patients had a recurrent stroke in the posterior circulation. Four patients were determined to have embolic infarcts, four patients had infarcts caused by plaques that occluded a branch or perforating artery (junctional plaques), and two patients had imaging that suggested hemodynamic infarction. Five of the ten patients with recurrent strokes had low distal flow. Of these, two patients had hemodynamic infarcts, one patient had an embolic infarct, and two patients had a junctional plaque. None of the five patients with normal flow had hemodynamic infarcts, three patients had embolic infarcts, and two patients had a junctional plaque. Conclusion: Despite the small numbers, there seems to be a higher risk of hemodynamic infarction in patients with low flow distal to symptomatic vertebrobasilar disease than in the presence of normal distal flow. This would confirm the hypothesis that in addition to embolic strokes and those related to junctional plaque, patients with low distal flow are at risk for hemodynamic infarction. Further studies are required to determine whether flow measurements could be used to select patients who may benefit from endovascular treatment of atherosclerotic vertebrobasilar disease.

Background: Fractional flow across an atherosclerotic lesion measured with TOF-MRA signal intensity ratio (SIR) may be used to gauge hemodynamic severity and to predict subsequent stroke. The degree of flow impairment may also be ascertained by quantitative MRA (QMRA). We analyzed performance of these noninvasive imaging parameters to estimate risk of subsequent posterior circulation events in VERiTAS. Methods: TOF-MRA data and QMRA were simultaneously acquired in VERiTAS. SIR were derived from TOF source images and normalized for analysis with volume flow ratios (VFR) on QMRA at standard anatomical landmarks and across the maximal stenosis. Statistics analyzed the correlation between SIR and VFR, and the ability of each to predict clinical events. Results: 72 subjects (mean age 65.6±10.3 years, 32 (44%) women) with posterior circulation atherosclerosis were enrolled in VERiTAS. Posterior communicating artery (PCOMM) flow to the posterior circulation was detected in 85% on the right, in 86% on the left, with bilateral PCOMM flow in 78%. Fractional flow measures or SIR across the maximal stenotic lesion evident on TOF MRA was reduced in 43%, increased in 16%, with no change in 40%. SIR from the proximal to distal basilar artery segments increased in 62%, was unchanged in 33% and decreased in 4% of cases. SI and VFR exhibited limited correlation at corresponding arterial segments. QMRA VFR indicative of low distal flow status predicted subsequent clinical events, unlike SIR. Conclusions: Evaluation of hemodynamics in posterior circulation atherosclerosis reveals superiority of QMRA to SIR in prospectively predicting recurrent ischemia. Collateral circulation, tandem disease and unique aspects of vertebrobasilar atherosclerosis likely influence the utility of SIR on TOF MRA.

Introduction: Despite theoretical concerns regarding hypoperfusion in patients with large artery occlusive disease, strict blood pressure (BP) control has become adopted as a safe strategy for stroke risk reduction. We examined the relationship between BP control, flow, and risk of subsequent stroke in the prospective Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS) Study. Hypothesis: Strict BP control may be less efficacious and safe in flow compromised patients with symptomatic vertebrobasilar (VB) disease. Methods: VERiTAS enrolled patients with recent VB TIA or stroke and ≥50% atherosclerotic stenosis or occlusion of vertebral or basilar arteries. Hemodynamic status using large vessel flow in the VB territory was designated as low or normal flow using quantitative MRA. Patients underwent standard medical management and follow-up for primary outcome event of VB territory stroke. Mean SBP during follow-up ( Results: The 72 enrolled subjects had an average of 3.8±1.2 BP recordings over the 20 ±8 months of follow-up; 40 (56%) had mean SBP of Conclusion: Among a subgroup of patients with VB disease and low flow, strict BP control (SBP

Introduction: The role of regional hypoperfusion as an important contributor to stroke risk in atherosclerotic vertebrobasilar (VB) disease has recently been confirmed by the observational Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS) Study. We examined the stability of hemodynamic status over time and relationship to stroke risk in patients followed in this prospective cohort. Methods: VERiTAS enrolled patients with recent VB TIA or stroke and ≥50% atherosclerotic stenosis or occlusion of vertebral and/or basilar arteries. Large vessel flow in the vertebrobasilar territory was assessed using quantitative MRA, and patients were designated as low flow or normal flow based on distal territory regional flow, incorporating collateral capacity. Patients underwent standard medical management and follow-up for primary outcome event of VB territory stroke. QMRA imaging was repeated at 6, 12 and 24 months. Flow status over time was examined relative to baseline, and relative to subsequent stroke risk using survival analysis. Results: Of 72 enrolled subjects, 50, 45 and 28 had follow-up QMRA at 6, 12 and 24 months respectively. 18 (25%) were characterized as low flow at baseline, 10% at 6 m, 20 % at 12m and 11% at 24m. Over 18±7months of follow-up, 7 of the 12 low flow patients (58%) with follow-up imaging had improved their flow status (low to normal) while only 3 of 44 normal flow patients (7%) had worsened. Baseline flow status has previously been demonstrated to be an independent stroke risk predictor; flow status at latest follow-up and prior to event remained a strong predictor of subsequent stroke (HR 4.9, CI 1.4 to16.9, p=0.01). Conclusions: There is potential both for improvement and worsening of hemodynamics in patients with atherosclerotic VB disease; improvement, likely attributable to development of collateral supply, was evident more frequently than worsening, presumably due to progression of disease. Flow status, both at baseline and over time, remains a robust risk factor for subsequent stroke, thus serving as an important prognostic marker.

Background and Purpose— Atherosclerotic vertebrobasilar disease is an important cause of posterior circulation stroke. To examine the role of hemodynamic compromise, a prospective multicenter study, Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS), was conducted. Here, we report clinical features and vessel flow measurements from the study cohort. Methods— Patients with recent vertebrobasilar transient ischemic attack or stroke and ≥50% atherosclerotic stenosis or occlusion in vertebral or basilar arteries (BA) were enrolled. Large-vessel flow in the vertebrobasilar territory was assessed using quantitative MRA. Results— The cohort (n=72; 44% women) had a mean age of 65.6 years; 72% presented with ischemic stroke. Hypertension (93%) and hyperlipidemia (81%) were the most prevalent vascular risk factors. BA flows correlated negatively with percentage stenosis in the affected vessel and positively to the minimal diameter at the stenosis site ( P P P =0.01). Distal flow status assessment, based on an algorithm incorporating collateral flow by examining distal vessels (BA and posterior cerebral arteries), correlated neither with multifocality of disease nor with severity of the maximal stenosis. Conclusions— Flow in stenotic posterior circulation vessels correlates with residual diameter and drops significantly with tandem disease. However, distal flow status, incorporating collateral capacity, is not well predicted by the severity or location of the disease.

Introduction: Risk assessment and estimation can be used to support the choice of behavioral and therapeutic interventions. Objective: To derive and validate a race and sex sensitive risk prediction algorithm for incident AIS. Methods: Risk prediction functions for incident AIS were developed and validated using ARIC, CHS, and MESA research databases obtained from the NHLBI BioLINCC. ARIC and CHS cohort members with prior stroke/TIA or cancer at baseline examination and CHS cohort members above age 84 years were excluded. A random 60% sample of the ARIC and CHS cohorts, separately, were pulled and combined to form the derivation cohort. The remaining 40% of ARIC and CHS data were pooled and used as the validation cohort. MESA was used as an external validation cohort. Subjects with missing data on established cardiovascular risk factors were excluded. Cox proportional hazards regression was used to develop best fitting prediction model in the derivation cohort. Performance of the model was assessed at 5 and 10 years. Measures of calibration and discrimination were undertaken in both validation cohorts. Results: The derivation cohort included 9,762 subjects (54.4% women, 23.8% blacks) with 708 cases of AIS with a median follow-up of 18.3 years. The ARIC-CHS validation cohort included 6,538 subjects (55.6% women, 22.8% blacks) with 475 AIS and a median follow-up of 18.3 years. The MESA validation cohort included 6,566 subjects (52.6% women, 27.9% blacks) with 106 AIS and a median follow-up of 7.6 years. The final risk equation demonstrated very good discrimination (concordance statistics: Harrell’s C = 0. 80, Somer’s D =.59). The accuracy of probabilistic predictions for 10-year stroke risk in the derivation cohort was 0.820 (p Conclusion: We have derived and validated a new race and sex sensitive prediction equation based on readily available predictors in clinical practice that quantifies absolute risk of first AIS at 5 and 10 years.

Objective: We have previously demonstrated an effect of age and Circle of Willis anatomic variants on individual major cerebral vessel flow rates, using quantitative magnetic resonance angiography (QMRA). We have now sought to establish normative flow ranges which could serve as clinically useful benchmarks for evaluating the hemodynamics of large vessel cerebrovascular occlusive disease. Methods: 326 healthy adult volunteers with no history of cerebrovascular disease underwent QMRA of cerebral vessels. Flows were measured bilaterally in the internal carotid artery (ICA), middle cerebral artery (MCA), anterior cerebral artery (ACA) A1 and A2 segments, posterior cerebral artery (PCA), basilar artery (BA), and vertebral artery (VA). Both individual vessel flow in ml/min, and indexed to total cerebral flow (TCBF=ICAs + VAs) was examined in relation to age and vascular anatomy, and percentile thresholds for normative flow were determined. Results: The volunteers ranged from 18 to 84 (mean 48) years old, with 48% female. All individual vessel flows declined with age (P Conclusions: Indexing individual flows to TCBF allows age-adjusted normative ranges to be defined by percentile categories. Definition of these ranges may allow examination of the hemodynamic effect of cerebrovascular occlusive disease, although it remains to be examined if specific percentile thresholds for individual distal vessel flow will be a useful predictor of increased hemodynamic stroke risk.

IV r-tPA has been shown to be an efficacious and cost-effective treatment for acute ischemic stroke (AIS). Lack of adequate reimbursement for treatment of AIS with r-tPA from the CMS may be a barrier for r-tPA use among Medicare beneficiaries. In October 2005, CMS introduced DRG 559- increased reimbursement for iv r-tPA administration. We evaluated the impact of demograhic factors and DRG 559 on use of iv r-tPA for AIS among Medicare beneficiaries. Methods: CMS Medicare claims database from MEDPAR for 2004 and CCW for 2005-07 were accessed. AIS was defined by the presence of a primary diagnosis according to an ICD-9 codes 433 and 434 with a fifth-digit subclassification 1 indicating occlusion with infarction of precerebral and cerebral arteries from DRG 14 and 559. AIS patients receiving iv r-tPA were identified by presence of ICD-9 procedure codes 99.10 and receiving such procedure within one day of admission. r-tPA drip and ship cases were identified and included as r-tPA drip & ship cases in the receiving hospitals. Patients transferred for acute stroke care to another short term general/specialty hospital were excluded as were admissions to hospitals other than short term general/specialty or critical access hospitals and those admissions in the rehab units of the short term general/specialty hospitals. Impact of reimbursement on r-tPA use was assessed using piecewise regression methods in STATA 11. Results: From January 2004 to September 2007 a total of 742,368 AIS admissions were evaluated and estimated use of r-tPA by age, sex, race/ethnicity and geographical region is presented in the table. Trends in use of r-tPA are depicted in the figure . The estimated intercepts and slopes in the figure by pre- and post-DRG 559 and age group depicts the possible effect of increased reimbursement on r-tPA use in this population. A significant increase in r-tPA use with the introduction of DRG 559 in October 2005 (i.e. month = 9 onwards) was noticed by the significant jump (p-value < 0.01) in the intercepts. Conclusion: The results generally suggest the highest use of r-tPA among ages 65-75, men, white race and in the Northeast region.The increase in r-tPA use may be explained by the impact of policy change with introduction of higher reimbursement for r-tPA for AIS among Medicare beneficiaries. Estimates of use of r-tPA by month and age group

Background and Purpose— Since the 1999 identification of clopidogrel-associated thrombotic thrombocytopenic purpura (TTP) through independent active surveillance, subsequent cases have been identified by pharmaceutical suppliers of clopidogrel and the Food and Drug Administration (FDA). For cases of clopidogrel-associated TTP reported between 1998 to 2002, we evaluated the quality and timeliness of data from 3 reporting systems-independent active surveillance (n=13), pharmaceutical suppliers (n=24), and the FDA (n=13)—and identified prognostic factors associated with mortality. Methods— This study assessed the completeness of information on TTP diagnosis, treatment response, and causality from the 3 reporting systems. In addition, predictors of mortality were identified through classification tree analysis. Results— Completeness, timeliness, and certainty of diagnosis were best for cases obtained by active surveillance, intermediate for cases reported to the pharmaceutical supplier, and poorest for cases reported directly to the FDA. Clopidogrel had been used for ≤2 weeks by 65%. The survival rate for patients with clopidogrel-associated TTP was 71.2%. Receipt of therapeutic plasma exchange within 3 days of onset of TTP increased the likelihood of survival (100% versus 27.3%, P Conclusions— Compared with reports submitted by suppliers or the FDA, reports obtained through active surveillance provided timelier and more complete information. Clopidogrel-associated TTP often occurs within 2 weeks of drug initiation, occasionally relapses, and has a high mortality if not treated promptly.