Vanita Tongbram

Neurothrombectomy devices for the treatment of acute ischemic stroke: state of the evidence

BACKGROUND Acute ischemic strokes are associated with poor outcomes and high health care burden. Evidence exists evaluating the use of neurothrombectomy devices in patients receiving currently recommended treatments that may have limited efficacy. PURPOSE To describe the state of the evidence supporting use of neurothrombectomy devices in the treatment of acute ischemic stroke. DATA SOURCES MEDLINE, SCOPUS, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and Web of Science were searched, without language restrictions, from their inception through May 2010. The MEDLINE and Cochrane Central Register of Controlled Trials searches were updated through November 2010. STUDY SELECTION Two independent investigators screened citations for human studies of any design or case series or case reports of patients with an acute ischemic stroke that evaluated a neurothrombectomy device and reported at least 1 clinical effectiveness outcome or harm. DATA EXTRACTION Using standardized protocols, 2 independent investigators extracted information about study characteristics and outcomes, and a third reviewer resolved disagreement. DATA SYNTHESIS 87 articles met eligibility criteria, including 18 prospective single-group studies, 7 noncomparative retrospective studies, and 62 case series or case reports. Two U.S. Food and Drug Administration (FDA)-cleared devices, the MERCI Retriever (Concentric Medical, Mountain View, California) (40%) and the Penumbra System (Penumbra, Alameda, California) (9%), represented a large portion of the available data. All prospective and retrospective studies provided data on successful recanalization with widely varying rates (43% to 78% with the MERCI Retriever and 83% to 100% with the Penumbra System). Rates of harms, including symptomatic (16 studies; 0% to 10% with the MERCI Retriever and 0% to 11% with the Penumbra System) or asymptomatic (13 studies; 28% to 43% and 1% to 30%, respectively) intracranial hemorrhage and vessel perforation or dissection (11 studies; 0% to 7% and 0% to 5%, respectively), also varied by device. Predictors of harm included older age, history of stroke, and higher baseline stroke severity scores, whereas successful recanalization was the sole predictor of good outcomes. LIMITATIONS Most available data are from single-group, noncomparative studies. In addition, the patient population most likely to benefit from these devices is undetermined. CONCLUSION Currently available neurothrombectomy devices offer intriguing treatment options in patients with acute ischemic stroke. Future trials should use a randomized design, with adequate power to show equivalency or noninferiority between competing strategies or devices, and strive to identify populations that are most likely to benefit from use of neurothrombectomy devices. PRIMARY FUNDING SOURCE Agency for Healthcare Research and Quality.

Statin use and the prevention of venous thromboembolism: a meta-analysis

Aims:  Statins are thought to have antithrombotic properties and may attenuate patients’ odds of developing venous thromboembolism (VTE), but clinical studies have yielded variable estimates of this effect. The aim was to conduct a meta‐analysis to evaluate the effect of statin use on development of VTE.

Oral Antidiabetic Drugs and Regression from Prediabetes to Normoglycemia: A Meta-Analysis

Background: Impaired glucose tolerance, impaired fasting glucose, and elevated hemoglobin A1c are intermediate stages, considered prediabetes, a precursor to overt type 2 diabetes mellitus. Prediabetes is associated with increased risk for cardiovascular disease, independent of diabetes development. Data have shown that various oral antidiabetic drugs can help people regress from prediabetes to normoglycemia. Objective: To evaluate the efficacy of oral antidiabetic drugs in promoting regression from prediabetes to normoglycemia. Methods: MEDLINE (1950–November 2011), EMBASE (1990–November 2011), and Cochrane Central Register of Controlled Trials (indexed September 2011) were systematically searched. A manual search of references from reports of clinical trials and review articles was performed to identify additional relevant studies. Randomized controlled trials 12 weeks or more in duration evaluating any of the oral antidiabetic drugs and studying regression from prediabetes to normoglycemia were included. A random-effects model was used to calculate pooled odds ratios with 95% confidence intervals. Results: Thirteen studies (N = 11,600 participants) were included in the metaanalysis. Use of oral antidiabetic drugs in prediabetic patients was shown to double the odds of achieving normoglycemia compared to controls (OR 2.03, 95% CI 1.54 to 2.67). When individual classes of oral antidiabetic drugs were evaluated, use of thiazolidinediones (OR 2.33, 95% CI 1.93 to 2.81) and α-glucosidase inhibitors (OR 2.02, 95% CI 1.26 to 3.24) was associated with significantly increased odds. However, biguanides (OR 2.04) and sulfonylureas (OR 1.84) failed to reach statistical significance (p = 0.06 and p = 0.39, respectively). Conclusions: In patients with prediabetes, oral antidiabetic drugs were associated with increased odds of regression to normoglycemia versus placebo/control. Only thiazolidinediones and α-glucosidase inhibitors provided a statistically significant increase in odds of regressing to normoglycemia.

Comparative Effectiveness of Low-Molecular-Weight Heparins versus Other Anticoagulants in Major Orthopedic Surgery: A Systematic Review and Meta-analysis

To evaluate the comparative efficacy and safety of low‐molecular‐weight heparins (LMWHs) versus other anticoagulants as venous thromboembolism prophylaxis in major orthopedic surgery.

Prolonged Versus Standard-Duration Venous Thromboprophylaxis in Major Orthopedic Surgery: A Systematic Review

BACKGROUND The optimal duration of thromboprophylaxis after major orthopedic surgery is unclear. PURPOSE To compare the benefits and harms of prolonged versus standard-duration thromboprophylaxis after major orthopedic surgery in adults. DATA SOURCES Cochrane Central Register of Controlled Trials and Scopus from 1980 to July 2011 and MEDLINE from 1980 through November 2011, without language restrictions. STUDY SELECTION Randomized trials reporting thromboembolic or bleeding outcomes that compared prolonged (≥21 days) with standard-duration (7 to 10 days) thromboprophylaxis. DATA ABSTRACTION Two independent reviewers abstracted data and rated study quality and strength of evidence. DATA SYNTHESIS Eight randomized, controlled trials (3 good-quality and 5 fair-quality) met the inclusion criteria. High-strength evidence showed that compared with standard-duration therapy, prolonged prophylaxis resulted in fewer cases of pulmonary embolism (PE) (5 trials; odds ratio [OR], 0.14 [95% CI, 0.04 to 0.47]; absolute risk reduction [ARR], 0.8%), asymptomatic deep venous thrombosis (DVT) (4 trials; relative risk [RR], 0.48 [CI, 0.31 to 0.75]; ARR, 5.8%), symptomatic DVT (4 trials; OR, 0.36 [CI, 0.16 to 0.81]; ARR, 1.5%), and proximal DVT (6 trials; RR, 0.29 [CI, 0.16 to 0.52]; ARR, 7.1%). Moderate-strength evidence showed fewer symptomatic objectively confirmed episodes of venous thromboembolism (4 trials; RR, 0.38 [CI, 0.19 to 0.77]; ARR, 5.7%), nonfatal PE (4 trials; OR, 0.13 [CI, 0.03 to 0.54]; ARR, 0.7%), and DVT (7 trials; RR, 0.37 [CI, 0.21 to 0.64]; ARR, 12.1%) with prolonged prophylaxis. High-strength evidence showed more minor bleeding events with prolonged prophylaxis (OR, 2.44 [CI, 1.41 to 4.20]; absolute risk increase, 6.3%), and insufficient evidence from 1 trial on hip fracture surgery suggested more surgical-site bleeding events (OR, 7.55 [CI, 1.51 to 37.64]) with prolonged prophylaxis. LIMITATIONS Data relevant to knee replacement or hip fracture surgery were scant and insufficient. Most trials had few events; the strength of evidence ratings that were used may not adequately capture uncertainty in such situations. CONCLUSION Prolonged prophylaxis decreases the risk for venous thromboembolism, PE, and DVT while increasing the risk for minor bleeding in patients undergoing total hip replacement.

Comparative effectiveness of combined pharmacologic and mechanical thromboprophylaxis versus either method alone in major orthopedic surgery: a systematic review and meta-analysis.

To evaluate the comparative efficacy and safety of combination pharmacologic and mechanical venous thromboembolism (VTE) prophylaxis versus either method alone in major orthopedic surgery.

Are the risk factors listed in warfarin prescribing information associated with anticoagulation-related bleeding? A systematic literature review

Warfarin significantly reduces thromboembolic risk, but perceptions of associated bleeding risk limit its use. The evidence supporting the association between bleeding and individual patient risks factors is unclear. This systematic review aims to determine the strength of evidence supporting an accentuated bleeding risk when patients with risk factors listed in the warfarin prescribing information are prescribed the drug. A systematic literature search of MEDLINE and Cochrane CENTRAL was conducted to identify studies reporting multivariate relationships between prespecified covariates and the risk of bleeding in patients receiving warfarin. The prespecified covariates were identified based on patient characteristics for bleeding listed in the warfarin package insert. Each covariate was evaluated for its association with specific types of bleeding. The quality of individual evaluations was rated as ‘good’, ‘fair’ or ‘poor’ using methods consistent with those recommended by the Agency for Healthcare Research and Quality (AHRQ). Overall strength of evidence was determined using the Grading of Recommendations Assessment, Development (GRADE) criteria and categorised as ‘insufficient’, ‘very low’, ‘low’, ‘moderate’ or ‘high’. Thirty‐four studies, reporting 134 multivariate evaluations of the association between a covariate and bleeding risk were identified. The majority of evaluations had a low strength of evidence for the association between covariates and bleeding and none had a high strength of evidence. Malignancy and renal insufficiency were the only two covariates that had a moderate strength of evidence for their association with major and minor bleeding respectively. The associations between covariates listed in the warfarin prescribing information and increased bleeding risk are not well supported by the medical literature.

Systematic review: comparative effectiveness of adjunctive devices in patients with ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention of native vessels

BackgroundDuring percutaneous coronary intervention (PCI), dislodgement of atherothrombotic material from coronary lesions can result in distal embolization, and may lead to increased major adverse cardiovascular events (MACE) and mortality. We sought to systematically review the comparative effectiveness of adjunctive devices to remove thrombi or protect against distal embolization in patients with ST-segment elevation myocardial infarction (STEMI) undergoing PCI of native vessels.MethodsWe conducted a systematic literature search of Medline, the Cochrane Database, and Web of Science (January 1996-March 2011), http://www.clinicaltrials.gov, abstracts from major cardiology meetings, TCTMD, and CardioSource Plus. Two investigators independently screened citations and extracted data from randomized controlled trials (RCTs) that compared the use of adjunctive devices plus PCI to PCI alone, evaluated patients with STEMI, enrolled a population with 95% of target lesion(s) in native vessels, and reported data on at least one pre-specified outcome. Quality was graded as good, fair or poor and the strength of evidence was rated as high, moderate, low or insufficient. Disagreement was resolved through consensus.Results37 trials met inclusion criteria. At the maximal duration of follow-up, catheter aspiration devices plus PCI significantly decreased the risk of MACE by 27% compared to PCI alone. Catheter aspiration devices also significantly increased the achievement of ST-segment resolution by 49%, myocardial blush grade of 3 (MBG-3) by 39%, and thrombolysis in myocardial infarction (TIMI) 3 flow by 8%, while reducing the risk of distal embolization by 44%, no reflow by 48% and coronary dissection by 70% versus standard PCI alone. In a majority of trials, the use of catheter aspiration devices increased procedural time upon qualitative assessment.Distal filter embolic protection devices significantly increased the risk of target revascularization by 39% although the use of mechanical thrombectomy or embolic protection devices did not significantly impact other final health outcomes. Distal balloon or any embolic protection device increased the achievement of MBG-3 by 61% and 20% and TIMI3 flow by 11% and 6% but did not significantly impact other intermediate outcomes versus control. Upon qualitative analysis, all device categories, with exception of catheter aspiration devices, appear to significantly prolong procedure time compared to PCI alone while none appear to significantly impact ejection fraction. Many of the final health outcome and adverse event evaluations were underpowered and the safety of devices overall is unclear due to insufficient amounts of data.ConclusionsIn patients with STEMI, for most devices, few RCTs evaluated final health outcomes over a long period of follow-up. Due to insufficient data, the safety of these devices is unclear.