George A. Lopez
University of Texas Health Science Center at Houston
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by George A. Lopez.
The Lancet | 2017
Daniel F. Hanley; Karen Lane; Nichol McBee; Wendy C. Ziai; Stanley Tuhrim; Kennedy R. Lees; Jesse Dawson; Dheeraj Gandhi; Natalie Ullman; W. Andrew Mould; Steven Mayo; A. David Mendelow; Barbara Gregson; Kenneth Butcher; Paul Vespa; David W. Wright; Carlos S. Kase; J. Ricardo Carhuapoma; Penelope M. Keyl; Marie Diener-West; John Muschelli; Joshua Betz; Carol B. Thompson; Elizabeth A. Sugar; Gayane Yenokyan; Scott Janis; Sayona John; Sagi Harnof; George A. Lopez; E. Francois Aldrich
BACKGROUND Intraventricular haemorrhage is a subtype of intracerebral haemorrhage, with 50% mortality and serious disability for survivors. We aimed to test whether attempting to remove intraventricular haemorrhage with alteplase versus saline irrigation improved functional outcome. METHODS In this randomised, double-blinded, placebo-controlled, multiregional trial (CLEAR III), participants with a routinely placed extraventricular drain, in the intensive care unit with stable, non-traumatic intracerebral haemorrhage volume less than 30 mL, intraventricular haemorrhage obstructing the 3rd or 4th ventricles, and no underlying pathology were adaptively randomly assigned (1:1), via a web-based system to receive up to 12 doses, 8 h apart of 1 mg of alteplase or 0·9% saline via the extraventricular drain. The treating physician, clinical research staff, and participants were masked to treatment assignment. CT scans were obtained every 24 h throughout dosing. The primary efficacy outcome was good functional outcome, defined as a modified Rankin Scale score (mRS) of 3 or less at 180 days per central adjudication by blinded evaluators. This study is registered with ClinicalTrials.gov, NCT00784134. FINDINGS Between Sept 18, 2009, and Jan 13, 2015, 500 patients were randomised: 249 to the alteplase group and 251 to the saline group. 180-day follow-up data were available for analysis from 246 of 249 participants in the alteplase group and 245 of 251 participants in the placebo group. The primary efficacy outcome was similar in each group (good outcome in alteplase group 48% vs saline 45%; risk ratio [RR] 1·06 [95% CI 0·88-1·28; p=0·554]). A difference of 3·5% (RR 1·08 [95% CI 0·90-1·29], p=0·420) was found after adjustment for intraventricular haemorrhage size and thalamic intracerebral haemorrhage. At 180 days, the treatment group had lower case fatality (46 [18%] vs saline 73 [29%], hazard ratio 0·60 [95% CI 0·41-0·86], p=0·006), but a greater proportion with mRS 5 (42 [17%] vs 21 [9%]; RR 1·99 [95% CI 1·22-3·26], p=0·007). Ventriculitis (17 [7%] alteplase vs 31 [12%] saline; RR 0·55 [95% CI 0·31-0·97], p=0·048) and serious adverse events (114 [46%] alteplase vs 151 [60%] saline; RR 0·76 [95% CI 0·64-0·90], p=0·002) were less frequent with alteplase treatment. Symptomatic bleeding (six [2%] in the alteplase group vs five [2%] in the saline group; RR 1·21 [95% CI 0·37-3·91], p=0·771) was similar. INTERPRETATION In patients with intraventricular haemorrhage and a routine extraventricular drain, irrigation with alteplase did not substantially improve functional outcomes at the mRS 3 cutoff compared with irrigation with saline. Protocol-based use of alteplase with extraventricular drain seems safe. Future investigation is needed to determine whether a greater frequency of complete intraventricular haemorrhage removal via alteplase produces gains in functional status. FUNDING National Institute of Neurological Disorders and Stroke.
International Journal of Stroke | 2013
Nicole R. Gonzales; Jharna Shah; Navdeep Sangha; Lenis Sosa; Rebecca Martinez; Loren Shen; Mallikarjunarao Kasam; Miriam M. Morales; Monir Hossain; Andrew D. Barreto; Sean I. Savitz; George A. Lopez; Vivek Misra; Tzu Ching Wu; Ramy El Khoury; Amrou Sarraj; Preeti Sahota; William J Hicks; Indrani Acosta; M. Rick Sline; Mohammad H. Rahbar; Xiurong Zhao; Jaroslaw Aronowski; James C. Grotta
Rationale Preclinical work demonstrates that the transcription factor peroxisome proliferator-activated receptor gamma plays an important role in augmenting phagocytosis while modulating oxidative stress and inflammation. We propose that targeted stimulation of phagocytosis to promote efficient removal of the hematoma without harming surrounding brain cells may be a therapeutic option for intracerebral hemorrhage. Aims The primary objective is to assess the safety of the peroxisome proliferator-activated receptor gamma agonist, pioglitazone, in increasing doses for three-days followed by a maintenance dose, when administered to patients with spontaneous intracerebral hemorrhage within 24 h of symptom onset compared with standard care. We will determine the maximum tolerated dose of pioglitazone. Study Design This is a prospective, randomized, blinded, placebo-controlled, dose-escalation safety trial in which patients with spontaneous intracerebral hemorrhage are randomly allocated to placebo or treatment. The Continual Reassessment Method for dose finding is used to determine the maximum tolerated dose of pioglitazone. Hematoma and edema resolution is evaluated with serial magnetic resonance imaging (MRI) at specified time points. Functional outcome will be evaluated at three- and six-months. Outcomes The primary safety outcome is mortality at discharge. Secondary safety outcomes include mortality at three-months and six-months, symptomatic cerebral edema, clinically significant congestive heart failure, edema, hypoglycemia, anemia, and hepatotoxicity. Radiographic outcomes will explore the time frame for resolution of 25%, 50%, and 75% of the hematoma. Clinical outcomes are measured by the National Institutes of Health Stroke Scale (NIHSS), the Barthel Index, modified Rankin Scale, Stroke Impact Scale-16, and EuroQol at three- and six-months.
Stroke | 2013
Amrou Sarraj; Karen C. Albright; Andrew D. Barreto; Amelia K Boehme; Clark W. Sitton; Jeanie Choi; Steven L Lutzker; Chung Huan J Sun; Wafi Bibars; Claude Nguyen; Osman Mir; Farhaan Vahidy; Tzu Ching Wu; George A. Lopez; Nicole R. Gonzales; Randall C. Edgell; Sheryl Martin-Schild; Hen Hallevi; Peng R. Chen; Mark Dannenbaum; Jeffrey L. Saver; David S. Liebeskind; Raul G. Nogueira; Rishi Gupta; James C. Grotta; Sean I. Savitz
Background and Purpose— Intra-arterial therapy (IAT) promotes recanalization of large artery occlusions in acute ischemic stroke. Despite high recanalization rates, poor clinical outcomes are common. We attempted to optimize a score that combines clinical and imaging variables to more accurately predict poor outcome after IAT in anterior circulation occlusions. Methods— Patients with acute ischemic stroke undergoing IAT at University of Texas (UT) Houston for large artery occlusions (middle cerebral artery or internal carotid artery) were reviewed. Independent predictors of poor outcome (modified Rankin Scale, 4–6) were studied. External validation was performed on IAT-treated patients at Emory University. Results— A total of 163 patients were identified at UT Houston. Independent predictors of poor outcome (P⩽0.2) were identified as score variables using sensitivity analysis and logistic regression. Houston Intra-Arterial Therapy 2 (HIAT2) score ranges 0 to 10: age (⩽59=0, 60–79=2, ≥80 years=4), glucose (<150=0, ≥150=1), National Institute Health Stroke Scale (⩽10=0, 11–20=1, ≥21=2), the Alberta Stroke Program Early CT Score (8–10=0, ⩽7=3). Patients with HIAT2≥5 were more likely to have poor outcomes at discharge (odds ratio, 6.43; 95% confidence interval, 2.75–15.02; P<0.001). After adjusting for reperfusion (Thrombolysis in Cerebral Infarction score ≥2b) and time from symptom onset to recanalization, HIAT2≥5 remained an independent predictor of poor outcome (odds ratio, 5.88; 95% confidence interval, 1.96–17.64; P=0.02). Results from the cohort of Emory (198 patients) were consistent; patients with HIAT2 score ≥5 had 6× greater odds of poor outcome at discharge and at 90 days. HIAT2 outperformed other previously published predictive scores. Conclusions— The HIAT2 score, which combines clinical and imaging variables, performed better than all previous scores in predicting poor outcome after IAT for anterior circulation large artery occlusions.
Neurocritical Care | 2010
Parita Bhuva; Sheng-Han Kuo; J. Claude Hemphill; George A. Lopez
Background and PurposeStroke is one of the most common neurological manifestations of infective endocarditis. The use of intravenous tissue plasminogen activator (t-PA) in the management of acute ischemic stroke is the accepted standard of practice.Current guidelines for intravenous (IV) t-PA therapy in acute ischemic stroke do not exclude patients with infective endocarditis.Summary of the CaseWe present three patients who received IV t-PA for acute ischemic stroke in the setting of infective endocarditis and developed multifocal intracranial hemorrhage as a complication.ConclusionInfective endocarditis related strokes are associated with a higher risk of hemorrhagic complications and our experience suggests that IV t-PA use may potentiate that risk.
Journal of Stroke & Cerebrovascular Diseases | 2012
Navdeep Sangha; Ramy El Khoury; Vivek Misra; George A. Lopez
Dabigatran etexelate is a new oral direct thrombin inhibitor that has been approved by the US Food and Drug Administration to prevent stroke in patients with nonvalvular atrial fibrillation. A 51-year-old man with a history of atrial fibrillation who was taking dabigatran presented with an acute ischemic stroke. The patient had a normal international normalized ratio, activated partial thromboplastin time, and an elevated thrombin time of 26.4 seconds. Recanalization of the middle cerebral artery with intravenous tissue plasminogen activator was apparent on digital subtraction angiography, and there was no evidence of intracerebral hemorrhage on the repeat computed tomographic scan. This is the first report of a patient who was taking dabigatran etexilate and who had an ischemic stroke caused by a middle cerebral artery occlusion, with an elevated thrombin time and radiographic recanalization with intravenous tissue plasminogen activator without evidence of hemorrhagic transformation.
Stroke | 2015
Alastair J.S. Webb; Natalie Ullman; Timothy C. Morgan; John Muschelli; Joshua Kornbluth; Issam A. Awad; Stephen Mayo; Michael Rosenblum; Wendy C. Ziai; Mario Zuccarrello; Francois Aldrich; Sayona John; Sagi Harnof; George A. Lopez; William C. Broaddus; Christine A.C. Wijman; Paul Vespa; Ross Bullock; Stephen J. Haines; Salvador Cruz-Flores; Stan Tuhrim; Michael D. Hill; Raj K. Narayan; Daniel F. Hanley
Background and Purpose— The ABC/2 score estimates intracerebral hemorrhage (ICH) volume, yet validations have been limited by small samples and inappropriate outcome measures. We determined accuracy of the ABC/2 score calculated at a specialized reading center (RC-ABC) or local site (site-ABC) versus the reference-standard computed tomography–based planimetry (CTP). Methods— In Minimally Invasive Surgery Plus Recombinant Tissue-Type Plasminogen Activator for Intracerebral Hemorrhage Evacuation-II (MISTIE-II), Clot Lysis Evaluation of Accelerated Resolution of Intraventricular Hemorrhage (CLEAR-IVH) and CLEAR-III trials. ICH volume was prospectively calculated by CTP, RC-ABC, and site-ABC. Agreement between CTP and ABC/2 was defined as an absolute difference up to 5 mL and relative difference within 20%. Determinants of ABC/2 accuracy were assessed by logistic regression. Results— In 4369 scans from 507 patients, CTP was more strongly correlated with RC-ABC (r2=0.93) than with site-ABC (r2=0.87). Although RC-ABC overestimated CTP-based volume on average (RC-ABC, 15.2 cm3; CTP, 12.7 cm3), agreement was reasonable when categorized into mild, moderate, and severe ICH (&kgr;=0.75; P<0.001). This was consistent with overestimation of ICH volume in 6 of 8 previous studies. Agreement with CTP was greater for RC-ABC (84% within 5 mL; 48% of scans within 20%) than for site-ABC (81% within 5 mL; 41% within 20%). RC-ABC had moderate accuracy for detecting ≥5 mL change in CTP volume between consecutive scans (sensitivity, 0.76; specificity, 0.86) and was more accurate with smaller ICH, thalamic hemorrhage, and homogeneous clots. Conclusions— ABC/2 scores at local or central sites are sufficiently accurate to categorize ICH volume and assess eligibility for the CLEAR-III and MISTIE III studies and moderately accurate for change in ICH volume. However, accuracy decreases with large, irregular, or lobar clots. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: MISTIE-II NCT00224770; CLEAR-III NCT00784134.
Stroke | 2011
Tzu Ching Wu; Mallik Kasam; Nusrat Harun; Hen Hallevi; Hesna Bektas; Indrani Acosta; Vivek Misra; Andrew D. Barreto; Nicole R. Gonzales; George A. Lopez; James C. Grotta; Sean I. Savitz
Background and Purpose— Patients with intracerebral hemorrhage (ICH) are at high risk for development of deep venous thrombosis. Current guidelines state that low-dose subcutaneous low molecular weight heparin or unfractionated heparin may be considered at 3 to 4 days from onset. However, insufficient data exist on hematoma volume in patients with ICH before and after pharmacological deep venous thrombosis prophylaxis, leaving physicians with uncertainty regarding the safety of this practice. Methods— We identified patients from our stroke registry (June 2003 to December 2007) who presented with ICH only or ICH+intraventricular hemorrhage and received either low molecular weight heparin subcutaneously or unfractionated heparin within 7 days of admission and had a repeat CT scan performed within 4 days of starting deep venous thrombosis prophylaxis. We calculated the change in hematoma volume from the admission and posttreatment CTs. Hematoma volume was calculated using the ABC/2 method and intraventricular hemorrhage volumes were calculated using a published method of hand drawn regions of interest. Results— We identified 73 patients with a mean age of 63 years and median National Institutes of Health Stroke Scale score 11.5. The mean baseline total hematoma volume was 25.8 mL±23.2 mL. There was an absolute change in hematoma volume from pre- and posttreatment CT of −4.3 mL±11.0 mL. Two patients developed hematoma growth. Repeat analysis of patients given pharmacological deep venous thrombosis prophylaxis within 2 or 4 days after ICH found no increase in hematoma size. Conclusions— Pharmacological deep venous thrombosis prophylaxis given subcutaneously in patients with ICH and/or intraventricular hemorrhage in the subacute period is generally not associated with hematoma growth.
Neurocritical Care | 2010
Elissa Wible; George A. Lopez
BackgroundTherapeutic hypothermia is becoming the standard-of-care for coma following out-of-hospital cardiac arrest. Pregnancy has been considered a contraindication for therapeutic hypothermia.MethodsCase report.ResultsA 44-year-old woman presented after a witnessed out-of-hospital ventricular fibrillation cardiac arrest. She remained comatose upon hospital admission and was treated with induced hypothermia via surface cooling pads. An intrauterine pregnancy of 20 weeks gestation was discovered on admission. One day after admission, a stillborn fetus was spontaneously delivered. The patient made a good neurologic recovery and now lives at home with her family.ConclusionDuring pregnancy, beneficence toward the pregnant woman must be the primary ethical guideline in emergent, life-threatening situations. Pregnancy should not be a contraindication to therapeutic hypothermia following cardiac arrest.
Neurology | 2008
Asma Zakaria; J. Javier Provencio; George A. Lopez
Historically, neurology has been a primarily outpatient specialty.1 The advent of modern neurosurgical techniques, as well as more elegant means of artificial ventilation in the 1960s, brought increasing numbers of neurologic patients to the intensive care units (ICU). Although these patients were primarily managed by medical and surgical–anesthesiologist intensivists, occasional consults for neurophysiologic testing, management of neuromuscular failure, and, more commonly, prognostication, would bring neurologists to the ICU. In the 1980s and 1990s, the surge in new neurosurgical procedures and advances in cardiovascular disease spurred on the development of a newer, different subset of neurologist. Some developed an interest in cerebrovascular diseases, while others ventured into the ICUs and carved a niche for a new subspecialty: neurocritical care. A small number of neurologists, anesthesiologists, neurosurgeons, and medical intensivists aimed to identify and correct the factors that were contributing to the high mortality rates in neurologic intensive care units (NICUs). Through the 1980s and 1990s, four major centers of NICU training emerged. These centers were headed by Dr. Allan Ropper at Massachusetts General Hospital, Dr. Matthew Fink at Columbia University, Dr. Thomas Bleck at University of Virginia at Charlottesville, and Dr. Dan Hanley at Johns Hopkins.2 These “Four fathers”3 of neurocritical care in the United States have trained numerous fellows who …
Current Treatment Options in Neurology | 2016
George A. Lopez
Opinion statementFever in the neurocritical care unit has a high prevalence and is associated with worse outcomes in patients with severe neurologic illness. While it is well accepted that fever is associated with worse outcomes in this patient population, it is unclear if aggressive temperature management will improve outcomes. Temperature should be monitored routinely in this high-risk population, fever worked up appropriately to identify infectious etiology, and reasonable measures taken to control elevated temperature. While infection is a common source of fever in patients with significant neurologic illness, the fever may also be exacerbated by the underlying brain injury. The clinician must decide at which point to initiate fever control measures, how aggressively to manage the fever, and which temperature to target for normothermia. Several pharmacological agents are available as first-line therapy. Depending on the degree and severity of the febrile response, advanced temperature-control devices should be added to pharmacological measures. Several types of temperature-control devices are available, including invasive (intravascular catheters) and noninvasive (external cooling pads) technologies. The clinician should utilize both pharmacologic and device-based temperature therapies to minimize the amount of time spent in a febrile state and help to mitigate the secondary brain injury brought on by fever.