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J P Mohr

Publications and source records attributed to J P Mohr.

At least 19 recordsLinked to original sources
PubMed2006

Predictors of hemorrhage in patients with untreated brain arteriovenous malformation.

BACKGROUND: Intracranial hemorrhage is a serious possible complication in patients with brain arteriovenous malformation (AVM). Several morphologic factors associated with hemorrhagic AVM presentation have been established, but their relevance for the risk of subsequent AVM hemorrhage remains unclear. METHODS: The authors analyzed follow-up data on 622 consecutive patients from the prospective Columbia AVM database, limited to the period between initial AVM diagnosis and the start of treatment (i.e., any endovascular, surgical, or radiation therapy). Univariate and multivariate logistic regression and Cox proportional hazard models were applied to analyze the effect of patient age, gender, AVM size, anatomic location, venous drainage pattern, and associated arterial aneurysms on the risk of intracranial hemorrhage at initial presentation and during follow-up. RESULTS: The mean pretreatment follow-up was 829 days (median: 102 days), during which 39 (6%) patients experienced AVM hemorrhage. Increasing age (hazard ratio [HR] 1.05, 95% CI 1.03 to 1.08), initial hemorrhagic AVM presentation (HR 5.38, 95% CI 2.64 to 10.96), deep brain location (HR 3.25, 95% CI 1.30 to 8.16), and exclusive deep venous drainage (HR 3.25, 95% CI 1.01 to 5.67) were independent predictors of subsequent hemorrhage. Annual hemorrhage rates on follow-up ranged from 0.9% for patients without hemorrhagic AVM presentation, deep AVM location, or deep venous drainage to as high as 34.4% for those harboring all three risk factors. CONCLUSIONS: Hemorrhagic arteriovenous malformation (AVM) presentation, increasing age, deep brain location, and exclusive deep venous drainage appear to be independent predictors for AVM hemorrhage during natural history follow-up. The risk of spontaneous hemorrhage may be low in AVMs without these risk factors.

Adolescent↗
PubMed2006

Cerebrovascular reactivity and vasospasm after subarachnoid hemorrhage: a pilot study.

The authors performed serial transcranial Doppler (TCD) and carbon dioxide reactivity (CO2R) testing in 20 aneurysmal subarachnoid hemorrhage patients to determine whether impaired cerebrovascular reactivity was associated with symptomatic vasospasm. Symptomatic vasospasm occurred in 9 of 14 patients with abnormal CO2R and in none of 6 patients with preserved reactivity (p = 0.011). Abnormal CO2R preceded the onset of vasospasm in 7 of 9 patients. Abnormal standard TCD testing was not associated with vasospasm.

Adult↗
PubMed2006

Factors associated with in-hospital mortality after administration of thrombolysis in acute ischemic stroke patients: an analysis of the nationwide inpatient sample 1999 to 2002.

BACKGROUND AND PURPOSE: The prospective trials evaluating the safety and efficacy of intravenous tissue plasminogen activator have generally been conducted at academic medical centers and community hospitals with an institutional commitment to stroke care. Relatively little is known about the safety of this therapy as it is used in the community. We therefore examined outcomes in acute stroke patients treated with thrombolysis using the largest discharge database available in the United States for the years 1999 to 2002. METHODS: Data were derived from the Nationwide Inpatient Sample for the years 1999 to 2002. Using the appropriate International Classification of Disease-Clinical Modification, 9th revision, codes, patients admitted through the emergency room with a primary diagnosis of acute ischemic stroke were selected for analysis. From these patients, those coded as receiving thrombolysis were identified. Multivariate logistic regression was performed on the thrombolysis and nonthrombolysis cohorts to identify independent predictors of in-hospital mortality from among those clinical elements available in the database. RESULTS: We identified 2594 patients treated with thrombolysis from a group of 248,964 patients admitted through the emergency room with a primary diagnosis of acute ischemic stroke. The thrombolysis cohort had a higher in-hospital mortality rate compared with the nonthrombolysis patients (11.4% versus 6.8%). The rate of intracerebral hemorrhage was 4.4% for the thrombolysis cohort and 0.4% for nonthrombolysis patients. Multivariate logistic regression showed advanced age, Asian/Pacific Islander race, congestive heart failure, and atrial fibrillation/flutter to be independent predictors of in-hospital mortality after thrombolysis. Thrombolysis volume, overall ischemic stroke volume, and teaching status were not significant predictors of in-hospital mortality after thrombolysis. CONCLUSIONS: Thrombolysis, as it is used in the community, has a safety profile that is similar to that observed in the large, prospective clinical trials.

Adult↗
PubMed2005

Stroke as a complication of congenital heart disease.

Patent foramen ovale is a common finding in the general population. It is associated with an increased risk of stroke, but it may not have a significant effect on recurrent stroke risk in medically treated patients. Recently, many questions have arisen with respect to best treatment for preventing recurrent stroke. Some data from a clinical trial of anticoagulation compared with antiplatelet therapy support antiplatelet treatment for secondary prevention. There are not enough data currently to support surgical or percutaneous closure of patent foramen ovale for stroke prevention.

Anticoagulants↗
PubMed2005

Aggregate analysis of the literature for unruptured intracranial aneurysm treatment.

BACKGROUND: Publication bias and/or true heterogeneity can skew aggregate impressions from scientific literature. To better determine aggregate measures for unruptured intracranial aneurysm (UIA) treatment, we analyzed adverse outcome rates of surgical clipping and endovascular coil embolization. METHODS: Two independent reviewers searched MEDLINE for studies publishing adverse outcome rates for endovascular coiling and surgical clipping between January 1990 and July 2003. Studies were classified as single-center, multicenter, or community-based. We defined adverse outcome rates as combined all-cause early or in-hospital morbidity and mortality. We determined cumulative adverse outcome rates by plotting precision measure (sample size) against trial-specific effect (adverse outcome rate). FINDINGS: We included 4 endovascular coiling multicenter/community-based studies (1019 patients) and 13 single-center studies (810 patients) and 5 surgical clipping multicenter/community-based studies (10,541 patients) and 23 single-center studies (1759 patients). Cumulative adverse outcome rates for endovascular coiling and surgical clipping were 8.8% (95% confidence interval [CI] 7.6%-10.1%) and 17.8% (95% CI 17.2%-18.6%). INTERPRETATION: Scattergram distribution illustrated the magnitude of bias in current literature reporting UIAs. Major parts of the literature may have underestimated surgical clipping morbidity and mortality, which can be attributed to bias from smaller retrospective studies. Neuroradiologic coiling studies were less likely to include factors contributing to inaccurate adverse outcome rates.

Embolization, Therapeutic↗
PubMed2004

Thrombin generation in non-cardioembolic stroke subtypes: the Hemostatic System Activation Study.

BACKGROUND: The association between hemostatic activation, stroke mechanism, and outcome is poorly defined. The Hemostatic System Activation Study (HAS) investigators measured serial levels of prothrombin fragment F1.2, a marker of thrombin generation, in patients enrolled in the Warfarin Aspirin Recurrent Stroke Study (WARSS). METHODS: HAS enrolled 631 of the 2,206 patients in WARSS. Strokes were subtyped according to inferred mechanism. Plasma was collected for F1.2 at randomization (within 30 days of stroke), 3 months, 12 months, and 18 months. The 3 to 6 month samples in aspirin-treated patients were used for the primary analysis. RESULTS: The authors analyzed 3 to 6 month samples on 320 patients. Higher F1.2 levels were associated with older age, female sex, and hypertension. There was no difference between mean F1.2 levels in 56 cryptogenic (0.9 +/- 0.32 nmol/L) and 114 non-cryptogenic (1.13 +/- 0.74 nmol/L) patients or across specific stroke subtypes. There was an 8.8%/year (p = 0.006) increase in mean F1.2 levels. There was a trend toward higher risk of recurrent stroke or death as F1.2 levels increased in aspirin (RR: 1.30, 95% CI: 0.57 to 2.94, p = 0.53) and warfarin treated patients (RR: 1.68, 95% CI: 0.48 to 5.94, p = 0.42). F1.2 levels were reduced on average 70% in warfarin-treated patients in a dose-dependent fashion. CONCLUSION: F1.2 levels did not appear to differ by stroke subtype, suggesting that factors other than underlying stroke pathophysiology influence thrombin generation in the post-acute stroke period. F1.2 levels were suppressed by warfarin in a dose-dependent fashion. Additional research is needed to determine the predictive value of F1.2 after stroke.

Aged↗
PubMed2004

Age as a determinant of adverse events in medically treated cryptogenic stroke patients with patent foramen ovale.

BACKGROUND AND PURPOSE: Patent foramen ovale (PFO) is associated with cryptogenic stroke. There is no study that assessed the effect of age on adverse event rates in cryptogenic stroke patients with PFO. The purpose of this retrospective analysis from PFO in Cryptogenic Stroke Study (PICSS) database was to assess the effect of age on the risk of adverse events in medically treated cryptogenic stroke patients with PFO. METHODS: 250 cryptogenic stroke patients from PICSS were followed-up for 24 months, with death and recurrent ischemic stroke as primary endpoints. Hazard ratios were calculated for determination of relative risk in cryptogenic stroke patients with and without PFO in 3 age groups (younger than 55, 55 to 64, and 65 years or older). RESULTS: Among the 2 younger age groups, the presence of PFO did not significantly affect the risk of adverse events (P=0.15; hazard ratio=0.21; 95% CI, 0.02 to 1.78; 2-year event rates, 2.0% versus 9.3%; and P=0.70; hazard ratio=0.72; 95% CI, 0.14 to 3.73; 2-year event rates, 10.0% versus 13.9%). However, in those aged 65 years or older, the risk of adverse events was significantly higher in the patients with PFO (P=0.01; hazard ratio=3.21; 95% CI, 1.33 to 7.75; 2-year event rates 37.9% versus 14.5%). CONCLUSIONS: In this exploratory analysis, the presence of PFO in the younger cryptogenic stroke patients did not increase the risk of adverse events. However, in the older patients, PFO significantly increased the risk of adverse events.

Adult↗
PubMed2004

Effect of aspirin and warfarin therapy in stroke patients with valvular strands.

BACKGROUND: Valvular strands are associated with ischemic stroke. The recurrent rate of adverse events in stroke patients with valvular strands has not been defined and, importantly, there are no randomized studies to evaluate efficacy of antithrombotic therapies in these patients. METHODS: Patent Foramen Ovale in Cryptogenic Stroke Study (PICSS) enrolled 630 stroke patients, of whom 312 (49.5%) were randomized to warfarin and 318 (50.5%) were randomized to aspirin; 265 patients experienced cryptogenic stroke and 365 experienced stroke with known subtypes. Endpoints were recurrent ischemic stroke or death from any cause. All transesophageal echocardiography studies were blindly, centrally analyzed and all endpoints were blindly adjudicated. RESULTS: Overall, of 619 studies analyzed, valvular strands were present in 39.4% of the patients (244/619), 5.8% (36/619) on the aortic valve and 27.8% (172/619) on the mitral valve, and 5.8% (36/619) on both valves. In an intention-to-treat analysis, there was no significant difference in the time to primary endpoints between patients with and without strands in the overall population (P=0.82; hazard ratio: 1.05; 95% CI: 0.70 to 1.57; 2-year event rates: 16.4% versus 15.5%). Among the patients with strands, there was no significant difference in the time to primary endpoints between those treated with warfarin or aspirin (P=0.21; hazard ratio: 0.67; 95% CI: 0.36 to 1.26; 2-year event rates: 13.5% versus 19.6%). CONCLUSIONS: While on medical therapy, valvular strands do not significantly increase recurrent adverse event rates in patients with ischemic stroke. Furthermore, the study does not provide evidence to support an advantage of warfarin or aspirin for this purpose.

Adult↗
PubMed2004

Antiphospholipid antibodies and subsequent thrombo-occlusive events in patients with ischemic stroke.

CONTEXT: The presence of antiphospholipid antibodies (aPL) has been associated with vascular occlusive events. However, the role of aPL in predicting ischemic events, particularly recurrent ischemic stroke, is controversial. OBJECTIVE: To evaluate the effect of baseline aPL positivity (ie, positivity for anticardiolipin antibodies [aCL], lupus anticoagulant antibodies [LA], or both) on subsequent thrombo-occlusive events, including recurrent stroke. DESIGN, SETTING, AND PARTICIPANTS: The Antiphospholipid Antibodies and Stroke Study (APASS), a prospective cohort study within the Warfarin vs Aspirin Recurrent Stroke Study (WARSS), a randomized double-blind trial (N = 2206) conducted at multiple US clinical sites from June 1993 through June 2000 and comparing adjusted-dose warfarin (target international normalized ratio, 1.4-2.8) and aspirin (325 mg/d) for prevention of recurrent stroke or death. APASS participants were 1770 (80%) WARSS participants who consented to enroll in the APASS, with usable baseline blood samples drawn prior to randomization to the WARSS and analyzed for aPL status within 90 days of index stroke by a central independent laboratory. Quality assurance was performed on approximately 10% of samples by a second independent laboratory. MAIN OUTCOME MEASURE: Two-year rate of the composite end point of death from any cause, ischemic stroke, transient ischemic attack, myocardial infarction, deep vein thrombosis, pulmonary embolism, and other systemic thrombo-occlusive events. The primary analysis assessed the outcome associated with aPL positivity within each WARSS treatment group separately, after risk-factor adjustment (since these aPL-positive vs aPL-negative comparisons were not randomized). RESULTS: Of the 1770 APASS patients, 720 (41%) were classified as aPL-positive and 1050 (59%) as aPL-negative. There was no increased risk of thrombo-occlusive events associated with baseline aPL status in patients treated with either warfarin (relative risk [RR], 0.99; 95% confidence interval [CI], 0.75-1.31; P =.94), or aspirin (RR, 0.94; 95% CI, 0.70-1.28; P =.71). The overall event rate was 22.2% among aPL-positive and 21.8% among aPL-negative patients. There was no treatment x aPL interaction (P =.91). Patients with baseline positivity for both LA and aCL antibodies tended to have a higher event rate (31.7%) than did patients who tested negative for both antibodies (24.0%) (unadjusted RR, 1.36; 95% CI, 0.97-1.92; P =.07). Classification and regression tree analyses did not identify a specific LA test or aCL isotype or titer that was associated with increased risk of thrombo-occlusive event. CONCLUSIONS: The presence of aPL (either LA or aCL) among patients with ischemic stroke does not predict either increased risk for subsequent vascular occlusive events over 2 years or a differential response to aspirin or warfarin therapy. Routine screening for aPL in patients with ischemic stroke does not appear warranted.

Aged↗
PubMed2004

Association of infratentorial brain arteriovenous malformations with hemorrhage at initial presentation.

BACKGROUND AND PURPOSE: The goal of this study was to analyze the association of hemorrhagic presentation with infratentorial brain arteriovenous malformations (AVMs). METHODS: The 623 consecutive, prospectively enrolled patients from the Columbia AVM Databank were analyzed in a cross-sectional study. Clinical presentation (diagnostic event) was categorized as intracranial hemorrhage or nonhemorrhagic presentation. From brain imaging and cerebral angiography, AVM location was classified as either infratentorial or supratentorial. Univariate and multivariate statistical models were applied to test the effect of age, sex, AVM size and location, venous drainage pattern, and associated (ie, feeding artery or intranidal) arterial aneurysms on the likelihood of hemorrhage at initial AVM presentation. RESULTS: Of the 623 patients, 72 (12%) had an infratentorial and 551 (88%) had a supratentorial AVM. Intracranial hemorrhage was the presenting symptom in 283 patients (45%), and infratentorial AVM location was significantly more frequent (18%) among patients who bled initially (6%; odds ratio [OR], 3.60; 95% confidence interval [CI], 2.09 to 6.20). This difference remained significant (OR, 1.99; 95% CI, 1.07 to 3.69) in the multivariate logistic regression model controlling for age, sex, AVM size, deep venous drainage, and associated arterial aneurysms. In the same model, the effect of other established determinants for AVM hemorrhage--ie, AVM size (in 1-mm increments; OR, 0.95; 95% CI, 0.94 to 0.96), deep venous drainage (OR, 3.09; 95% CI, 1.87 to 5.12), and associated aneurysms (OR, 2.78; 95% CI, 1.76 to 4.40)--remained significant. CONCLUSIONS: Our findings suggest that infratentorial AVM location is independently associated with hemorrhagic AVM presentation.

Adult↗
PubMed2003

Urgent endovascular revascularization for symptomatic intracranial atherosclerotic stenosis.

BACKGROUND: Endovascular revascularization for intracranial atherosclerotic stenoses is being increasingly performed at major medical centers and has been reported to be technically feasible and safe. The authors report their experience with patients who underwent such a procedure for impending stroke and neurologic instability. METHOD: All 18 patients (21 intracranial lesions) treated between 1997 and 2002 at the authors' institution with endovascular revascularization were retrospectively reviewed. Each patient had failed maximal medical therapy and was thought to be at high risk for an imminent stroke. RESULTS: Endovascular revascularization was performed on eight distal internal carotid artery lesions, six middle cerebral artery lesions, four intracranial vertebral artery lesions, and three basilar artery lesions. Recanalization was complete in 5 arteries (Thrombolysis in Myocardial Infarction [TIMI] Grade III), partial in 14 arteries (TIMI Grade II), and complete occlusion (TIMI 0) developed in 1 artery. In a patient with a tight basilar stenosis, no angioplasty could be performed because of the inability to cross the stenosis with the guidewire. Major periprocedural complications occurred in 9 (50%) patients: intracranial hemorrhage in 3 (17%), disabling ischemic stroke in 2 (11%), and major extracranial hemorrhage in 4 (22%). Three patients died: one from intracerebral hemorrhage and two from cardiorespiratory failure. CONCLUSIONS: Endovascular revascularization of intracranial vessels is technically feasible and may be performed successfully. However, periprocedural complication and fatality rates in neurologically unstable patients are high. The results suggest that patient selection, procedure timing, and periprocedural medical management are critical factors to reduce periprocedural morbidity and mortality.

Adult↗