R W Smalling

University of Texas at Austin, Austin, Texas, United States

Are you R W Smalling?

Claim your profile

Publications (197)952.41 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper describes the stroke volume selection and operational design for the TORVAD, a synchronous, positive-displacement ventricular assist device (VAD). A lumped parameter model was used to simulate hemodynamics with the TORVAD compared to those under continuous flow VAD support. Results from the simulation demonstrated that a TORVAD with a 30 mL stroke volume ejecting with an early diastolic counterpulse provides comparable systemic support to the HeartMate II (HMII) (cardiac output 5.7 L/min up from 3.1 L/min in simulated heart failure). By taking advantage of synchronous pulsatility, the TORVAD delivers full hemodynamic support with nearly half the VAD flow rate (2.7 L/min compared to 5.3 L/min for the HMII) by allowing the left ventricle to eject during systole, thus preserving native aortic valve flow (3.0 L/min compared to 0.4 L/min for the HMII, down from 3.1 L/min at baseline). The TORVAD also preserves pulse pressure (26.7 mmHg compared to 12.8 mmHg for the HMII, down from 29.1 mmHg at baseline). Preservation of aortic valve flow with synchronous pulsatile support could reduce the high incidence of aortic insufficiency and valve cusp fusion reported in patients supported with continuous flow VADs.
    ASAIO journal (American Society for Artificial Internal Organs: 1992) 12/2014; · 1.39 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A coordinated system of care for patients with ST-segment elevation myocardial infarctions that includes prehospital administration of reduced-dose fibrinolytic agents coupled with urgent percutaneous coronary intervention (PCI), termed FAST-PCI, has been shown to be at least as effective as primary PCI (PPCI) alone. However, this reduced-dose fibrinolytic strategy could be associated with increased bleeding risk, especially in elderly patients. The purpose of this study was to examine 30-day outcomes in patients aged ≥75 years with ST-segment elevation myocardial infarctions treated with either strategy. Data from 120 patients aged ≥75 years treated with FAST-PCI were compared with those of 94 patients aged ≥75 years treated with PPCI. The primary comparator was mortality at 30 days. Stroke, reinfarction, and major bleeding were also compared. The groups were well matched for age, cardiac risk factors, and ischemic times. At 30 days, mortality was lower with FAST-PCI than with PPCI (4.2% vs 18.1%, p <0.01). Rates of stroke, reinfarction, and major bleeding (4% vs 2%) were similar in the 2 groups. The FAST-PCI cohort had lower rates of cardiogenic shock on hospital arrival (15% vs 26%, p = 0.05) and completely occluded infarct arteries (Thrombolysis In Myocardial Infarction [TIMI] grade 0 flow, 35% vs 61%, p <0.01). In conclusion, for patients aged ≥75 years with ST-segment elevation myocardial infarctions, a FAST-PCI strategy in a coordinated system of care was associated with reduced 30-day mortality, earlier infarct artery patency, and lower incidence of cardiogenic shock at arrival compared with PPCI, without apparent bleeding, stroke, or reinfarction penalties.
    The American journal of cardiology 10/2013; · 3.58 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: In acute myocardial infarction, left ventricular (LV) unloading reduces endothelin-1 (ET-1) release. We tested that endogenous ET-1 released during acute myocardial infarction might mediate ischemia/reperfusion (I/R) injury by stimulating increased intracellular calcium concentration, [Ca(2+)]i, and apoptosis. Methods: Rabbits were subjected to 1 h of coronary artery occlusion followed by 3 h of reperfusion. Unloading was initiated 15 min prior to reperfusion and was maintained during reperfusion. The control group was subjected to reperfusion. Animals were treated with ET-1 receptor antagonist BQ123. In parallel, isolated rabbit cardiomyocytes subjected to simulated I/R with or without ET-1 or BQ123, intracellular Ca(2+) and cell death were assessed with flow cytometry. Results: LV unloading prior to reperfusion reduced myocardial ET-1 release at 2 h of reperfusion. Infarct size was reduced in unloaded and BQ123 groups versus controls. LV unloading and BQ123 treatment reduced the percentage of apoptotic cells associated with increases in Bcl-2 protein levels in ischemic regions. BQ123 reduced both ET-1-induced [Ca(2+)]i increase and cell death for myocytes subjected to stimulated I/R. Conclusion: We propose that components of reperfusion injury involve ET-1 release which stimulates calcium overload and apoptosis. Intravenous ET-1 receptor blockade prior to reperfusion may be a protective adjunct to reperfusion therapy in acute myocardial infarction patients.
    Cardiology 06/2013; 125(4):242-249. · 1.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The goal of this study was to characterize determinants of infarct size in the multicenter randomized Counterpulsation to Reduce Infarct Size Pre-PCI Acute Myocardial Infarction (CRISP-AMI) trial. Contemporary determinants of infarct size in patients presenting with acute anterior myocardial infarction without shock and undergoing percutaneous revascularization have been incompletely characterized. In CRISP-AMI, 337 patients with acute anterior ST segment elevation myocardial infarction but without cardiogenic shock at 30 sites in 9 countries were randomized to initiation of intra-aortic balloon counterpulsation before primary percutaneous coronary intervention versus standard of care. The primary outcome was infarct size as measured by cardiac magnetic resonance imaging 3 to 5 days after percutaneous coronary intervention. Of 337 randomized patients, complete periprocedural and infarct size data were available in 250 patients (74%). After a comparison of baseline characteristics to ensure no significant differences, patients with missing data were excluded. Using multiple linear regression of 23 variables, time from symptom onset to first device (β = 0.022, p = 0.047) and preprocedural Thrombolysis In Myocardial Infarction flow 0/1 (β = 15.28, p <0.001) were independent predictors of infarct size. Infarct size increased by 0.43% per 30 minutes in early reperfusion and by 0.63% every 30 minutes in late reperfusion. In conclusion, in patients with acute anterior ST elevation myocardial infraction without cardiogenic shock, total ischemic time and preprocedural Thrombolysis In Myocardial Infarction flow 0/1 were associated with increased infarct size as determined by cardiac magnetic resonance imaging. These findings underscore the importance of systems of care aimed at reducing total ischemic time to open infarct arteries.
    The American journal of cardiology 06/2013; · 3.58 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In patients with acute ST-elevation myocardial infarction (STEMI), a strategy of prehospital reduced dose fibrinolytic administration coupled with urgent percutaneous coronary intervention (PCI), termed FAST-PCI strategy, has been found to be superior to primary PCI (PPCI) alone. A coordinated STEMI system of care that includes FAST-PCI should offer better outcomes than a system in which prehospital diagnosis of STEMI is followed by PPCI alone. The aim of this study was to compare the in-hospital outcomes for patients treated with the FAST-PCI approach with outcomes for patients treated with the PPCI approach in a common system. The in-hospital data for 253 STEMI patients (March 2003-December 2009) treated with a FAST-PCI protocol were compared with 124 patients (January 2010-August 2011) treated with PPCI strategy alone. In-hospital mortality was the primary comparator. Stroke, major bleeding, and reinfarction during index hospitalization were also compared. The in-hospital mortality was significantly lower with FAST-PCI than with PPCI (2.77% vs 10.48%, p = 0.0017). Rates of stroke, reinfarction, and major bleeding were similar in the 2 groups. There was a lower frequency of pre-PCI Thrombolysis In Myocardial Infarction 0 flow (no patency) seen in patients treated with FAST-PCI compared with the PPCI patients (26.7% vs 62.7%, p <0.0001). Earlier infarct artery patency in the FAST-PCI group had a favorable impact on the incidence of cardiogenic shock on hospital arrival (3.1% vs 20.9%, p <0.0001). In conclusion, compared with a PPCI strategy in a common STEMI system of care, the FAST-PCI strategy was associated with earlier infarct artery patency and lower incidence of cardiogenic shock, as well as with reduced in-hospital mortality.
    The American journal of cardiology 03/2013; · 3.58 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of this investigation is to use a computational model to compare a synchronized valveless pulsatile left ventricular assist device with continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate the support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous pulsatile valveless dual-piston positive displacement pump. These results were compared with measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared with the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device.
    ASAIO journal (American Society for Artificial Internal Organs: 1992) 03/2013; 59(2):107-16. · 1.39 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Combined intravascular ultrasound and intravascular photoacoustic (IVUS/IVPA) imaging has been previously established as a viable means for assessing atherosclerotic plaque morphological and compositional characteristics using both endogenous and exogenous contrast. In this study, IVUS/IVPA imaging of atherosclerotic rabbit aortas following systemic injection of gold nanorods (AUNRs) with peak absorbance within the tissue optical window is performed. Ex vivo imaging results reveal a high photoacoustic signal from localized AUNRs in regions with atherosclerotic plaques. Corresponding histological staining further confirms the preferential extravasation of AUNRs in atherosclerotic regions with compromised luminal endothelium and acute inflammation. The ability to detect AUNRs using combined IVUS and photoacoustic imaging in the presence of luminal saline and luminal blood is evaluated using both spectroscopic and single wavelength IVPA imaging techniques. Results demonstrate that AUNR detection within the arterial wall can be achieved using both methods, even in the case of imaging through luminal blood.
    Journal of Biomedical Optics 10/2012; 17(10):106016. · 2.75 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We present a preliminary study demonstrating the capability of ultrasound-guided intravascular photoacoustic (IVPA) imaging to visualize the depth-resolved distribution of lipid deposits in atherosclerotic plaques in vivo. Based on the characteristic optical absorption of lipid in the near infrared wavelength range, IVPA imaging at a single, 1720 nm, wavelength was used to provide a spatially-resolved, direct measurement of lipid content in atherosclerotic arteries. By overlaying an IVPA image with a spatially co-registered intravascular ultrasound (IVUS) image, the combined IVPA/IVUS image was used to visualize lipid distribution within the vessel wall. Ultrasound-guided IVPA imaging was performed in vivo in the abdominal aorta of a Watanabe heritable hyperlipidemic (WHHL) rabbit. Subsequently, the excised rabbit aorta filled with a solution of red blood cells (RBC) was then imaged ex vivo, and histology was obtained in the section adjacent to the imaged cross-section. To demonstrate the potential for future clinical application of IVPA/IVUS imaging, a sample of diseased human right coronary artery (RCA) was also imaged. Both in vivo and ex vivo IVPA images clearly showed the distribution of lipid in the atherosclerotic vessels. In vivo IVPA imaging was able to identify diffuse, lipid-rich plaques in the WHHL rabbit model of atherosclerosis. Furthermore, IVPA imaging at a single wavelength was able to identify the lipid core within the human RCA ex vivo. Our results demonstrate that ultrasound-guided IVPA imaging can identify lipid in atherosclerotic plaques in vivo. Importantly, the IVPA/IVUS images were obtained in presence of luminal blood and no saline flush or balloon occlusion was required. Overall, our studies suggest that ultrasound-guided IVPA imaging can potentially be used for depth-resolved visualization of lipid deposits within the anatomical context of the vessel wall and lumen. Therefore, IVUS/IVPA imaging may become an important tool for the detection of rupture-prone plaques.
    Ultrasound in medicine & biology 10/2012; · 2.46 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pilot studies of in vivo combined intravascular ultrasound (IVUS) and intravascular photoacoustic (IVPA) imaging are reported. A recently introduced prototype of an integrated IVUS/IVPA imaging catheter consisting of a single-element ultrasound transducer and a light delivery system based on a single optical fiber was adapted and used for in vivo imaging of a coronary stent deployed in a rabbit's thoracic aorta in the presence of luminal blood. The results suggest that in vivo IVUS/IVPA imaging is feasible using the integrated IVUS/IVPA imaging catheter. The challenges of in vivo combined IVUS/IVPA imaging are discussed, and further improvements on the design of the catheter and the clinical imaging system are proposed.
    Journal of Biomedical Optics 09/2012; 17(9):96008-1. · 2.75 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Intravascular photoacoustic (IVPA) imaging can characterize atherosclerotic plaque composition on the basis of the optical absorption contrast between different tissue types. Given the high optical absorption of lipid at 1720 nm wavelength, an atherosclerotic rabbit aorta was imaged at this wavelength ex vivo using an integrated intravascular ultrasound (IVUS) and IVPA imaging catheter in the presence of luminal blood. Strong optical absorption of lipid combined with low background signal from other tissues provides a high-contrast, depth-resolved IVPA image of lipid. The ability to image lipid at a single wavelength without removing luminal blood suggests that in vivo detection of lipid in atherosclerotic plaques using combined IVUS/IVPA imaging is possible.
    Optics Letters 04/2012; 37(7):1244-6. · 3.39 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Combined intravascular photoacoustic (IVPA) and intravascular ultrasound (IVUS) imaging has been previously established as a viable means for imaging atherosclerotic plaques using both endogenous and exogenous contrast. In this study, IVUS/IVPA imaging of an atherosclerotic rabbit aorta following injection of gold nanorods (AuNR) with peak absorbance within the tissue optical window was performed. Ex-vivo imaging results revealed high photoacoustic signal from localized AuNR. Corresponding histological cross-sections and digital photographs of the artery lumen confirmed the presence of AuNR preferentially located at atherosclerotic regions and in agreement with IVPA signal. Furthermore, an integrated IVUS/IVPA imaging catheter was used to image the AuNR in the presence of luminal blood. The results suggest that AuNR allow for IVPA imaging of exogenously labeled atherosclerotic plaques with a comparatively low background signal and without the need for arterial flushing.
    Proc SPIE 02/2012;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The EVEREST II (Endovascular Valve Edge-to-Edge Repair) High Risk Study (HRS) assessed the safety and effectiveness of the MitraClip device (Abbott Vascular, Santa Clara, California) in patients with significant mitral regurgitation (MR) at high risk of surgical mortality rate. Patients with severe MR (3 to 4+) at high risk of surgery may benefit from percutaneous mitral leaflet repair, a potentially safer approach to reduce MR. Patients with severe symptomatic MR and an estimated surgical mortality rate of ≥12% were enrolled. A comparator group of patients screened concurrently but not enrolled were identified retrospectively and consented to compare survival in patients treated by standard care. Seventy-eight patients underwent the MitraClip procedure. Their mean age was 77 years, >50% had previous cardiac surgery, and 46 had functional MR and 32 degenerative MR. MitraClip devices were successfully placed in 96% of patients. Protocol-predicted surgical mortality rate in the HRS and concurrent comparator group was 18.2% and 17.4%, respectively, and Society of Thoracic Surgeons calculator estimated mortality rate was 14.2% and 14.9%, respectively. The 30-day procedure-related mortality rate was 7.7% in the HRS and 8.3% in the comparator group (p = NS). The 12-month survival rate was 76% in the HRS and 55% in the concurrent comparator group (p = 0.047). In surviving patients with matched baseline and 12-month data, 78% had an MR grade of ≤2+. Left ventricular end-diastolic volume improved from 172 ml to 140 ml and end-systolic volume improved from 82 ml to 73 ml (both p = 0.001). New York Heart Association functional class improved from III/IV at baseline in 89% to class I/II in 74% (p < 0.0001). Quality of life was improved (Short Form-36 physical component score increased from 32.1 to 36.1 [p = 0.014] and the mental component score from 45.5 to 48.7 [p = 0.065]) at 12 months. The annual rate of hospitalization for congestive heart failure in surviving patients with matched data decreased from 0.59 to 0.32 (p = 0.034). The MitraClip device reduced MR in a majority of patients deemed at high risk of surgery, resulting in improvement in clinical symptoms and significant left ventricular reverse remodeling over 12 months. (Pivotal Study of a Percutaneous Mitral Valve Repair System [EVEREST II]; NCT00209274).
    Journal of the American College of Cardiology 01/2012; 59(2):130-9. · 14.09 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Acute anterior myocardial infarctions caused by proximal left anterior descending (LAD) artery occlusions are associated with a higher morbidity and mortality. Early identification of high-risk patients via the 12-lead electrocardiogram (ECG) could assist physicians and emergency response teams in providing early and aggressive care for patients with anterior ST-elevation myocardial infarctions (STEMI). Approximately 25% of US hospitals have primary percutaneous coronary intervention (PCI) capability for the treatment of acute myocardial infarctions. Given the paucity of hospitals capable of PCI, early identification of more severe myocardial infarction may prompt emergency medical service routing of these patients to PCI-capable hospitals. We sought to determine if the 12 lead ECG is capable of predicting proximal LAD artery occlusions. In a retrospective, post-hoc analysis of the Pre-Hospital Administration of Thrombolytic Therapy with Urgent Culprit Artery Revascularization pilot trial, we compared the ECG findings of proximal and nonproximal LAD occlusions for patients who had undergone an ECG within 180 minutes of symptom onset. In this study, 72 patients had anterior STEMIs, with ECGs performed within 180 minutes of symptom onset. In patients who had undergone ECGs within 60 minutes (n = 35), the mean sum of ST elevation (STE) in leads V1 through V6 plus ST depression (STD) in leads II, III, and aVF was 19.2 mm for proximal LAD occlusions and 11.7 mm for nonproximal LAD occlusions (P = 0.007). A sum STE in V1 through V6 plus STD in II, III, and aVF of at least 17.5 mm had a sensitivity of 52.3%, specificity of 92.9%, positive predictive value of 91.7%, and negative predictive value of 56.5% for proximal LAD occlusions. When the ECG was performed more than 60 minutes after symptom onset (n = 37), there was no significant difference in ST-segment deviation between the 2 groups. The sum STE (V1-V6) and STD (II, III, aVF) on a 12-lead ECG can be used to predict proximal LAD occlusions if performed within the first hour of symptom onset. This should be considered a high-risk finding and may prompt prehospital direction of such patients to PCI-capable hospitals.
    The western journal of emergency medicine 11/2011; 12(4):408-13.
  • Source
    Iulia M Graf, Raz Miri, Richard W Smalling, Stanislav Emelianov
    [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: Recent advances in computational methods and medical imaging techniques have enabled non-invasive exploration of cardiovascular pathologies, from cardiac level to complex arterial networks. The potential of cardiac and vascular modeling in guiding and monitoring therapies could be further extended through the integration of the two systems. Areas covered: This review includes advances in methods for cardiac electromechanics and vascular flow simulations. The results of a literature search depicting the state of the art in cardiac and vascular modeling are reviewed. The paper goes on to address the benefits and challenges of combined cardiovascular modeling, highlighting the relevance of specific cardiovascular features and implementation. Various alternative approaches and insights on future directions are presented and analyzed with respect to their applicability to clinical practice. Expert opinion: The article has emerged from the exploration of currently available cardiac and vascular mathematical tools and their corresponding clinical application. The summarized analysis suggests that future efforts should be aimed at developing more accurate and patient-specific mathematical models integrating cardiac and vascular functions to enhance the knowledge of cardiovascular pathologies.
    Expert Opinion on Medical Diagnostics 11/2011; 5(6):501-15.
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND AND MOTIVATION: The structure, composition and mechanics of carotid artery are good indicators of early progressive atherosclerotic lesions. The combination of three imaging modalities (ultrasound, strain rate and photoacoustic imaging) which could provide corroborative information about the named arterial properties could enhance the characterization of intimal xanthoma. The experiments were performed using a New Zealand white rabbit model of atherosclerosis. The aorta excised from an atherosclerotic rabbit was scanned ex vivo using the three imaging techniques: (1) ultrasound imaging of the longitudinal section: standard ultrasound B-mode (74Hz frame rate); (2) strain rate imaging: the artery was flushed with blood and a 1.5Hz physiologic pulsation was induced, while the ultrasound data were recorded at higher frame rate (296Hz); (3) photoacoustic imaging: the artery was irradiated with nanosecond pulsed laser light of low fluence in the 1210-1230nm wavelength range and the photoacoustic data was recorded at 10Hz frame rate. Post processing algorithms based on cross-correlation and optical absorption variation were implemented to derive strain rate and spectroscopic photoacoustic images, respectively. Based on the spatio-temporal variation in displacement of different regions within the arterial wall, strain rate imaging reveals differences in tissue mechanical properties. Additionally, spectroscopic photoacoustic imaging can spatially resolve the optical absorption properties of arterial tissue and identify the location of lipid pools. The study demonstrates that ultrasound, strain rate and photoacoustic imaging can be used to simultaneously evaluate the structure, the mechanics and the composition of atherosclerotic lesions to improve the assessment of plaque vulnerability.
    Ultrasonics 10/2011; 52(3):435-41. · 2.03 Impact Factor
  • Article: Reply.
    JACC. Cardiovascular Interventions 09/2011; 4(9):1051-1052. · 1.07 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Intra-aortic balloon counterpulsation (IABC) is an adjunct to revascularization in patients with cardiogenic shock and reduces infarct size when placed prior to reperfusion in animal models. To determine if routine IABC placement prior to reperfusion in patients with anterior ST-segment elevation myocardial infarction (STEMI) without shock reduces myocardial infarct size. An open, multicenter, randomized controlled trial, the Counterpulsation to Reduce Infarct Size Pre-PCI Acute Myocardial Infarction (CRISP AMI) included 337 patients with acute anterior STEMI but without cardiogenic shock at 30 sites in 9 countries from June 2009 through February 2011. Initiation of IABC before primary percutaneous coronary intervention (PCI) and continuation for at least 12 hours (IABC plus PCI) vs primary PCI alone. Infarct size expressed as a percentage of left ventricular (LV) mass and measured by cardiac magnetic resonance imaging performed 3 to 5 days after PCI. Secondary end points included all-cause death at 6 months and vascular complications and major bleeding at 30 days. Multiple imputations were performed for missing infarct size data. The median time from first contact to first coronary device was 77 minutes (interquartile range, 53 to 114 minutes) for the IABC plus PCI group vs 68 minutes (interquartile range, 40 to 100 minutes) for the PCI alone group (P = .04). The mean infarct size was not significantly different between the patients in the IABC plus PCI group and in the PCI alone group (42.1% [95% CI, 38.7% to 45.6%] vs 37.5% [95% CI, 34.3% to 40.8%], respectively; difference of 4.6% [95% CI, -0.2% to 9.4%], P = .06; imputed difference of 4.5% [95% CI, -0.3% to 9.3%], P = .07) and in patients with proximal left anterior descending Thrombolysis in Myocardial Infarction flow scores of 0 or 1 (46.7% [95% CI, 42.8% to 50.6%] vs 42.3% [95% CI, 38.6% to 45.9%], respectively; difference of 4.4% [95% CI, -1.0% to 9.7%], P = .11; imputed difference of 4.8% [95% CI, -0.6% to 10.1%], P = .08). At 30 days, there were no significant differences between the IABC plus PCI group and the PCI alone group for major vascular complications (n = 7 [4.3%; 95% CI, 1.8% to 8.8%] vs n = 2 [1.1%; 95% CI, 0.1% to 4.0%], respectively; P = .09) and major bleeding or transfusions (n = 5 [3.1%; 95% CI, 1.0% to 7.1%] vs n = 3 [1.7%; 95% CI, 0.4% to 4.9%]; P = .49). By 6 months, 3 patients (1.9%; 95% CI, 0.6% to 5.7%) in the IABC plus PCI group and 9 patients (5.2%; 95% CI, 2.7% to 9.7%) in the PCI alone group had died (P = .12). Among patients with acute anterior STEMI without shock, IABC plus primary PCI compared with PCI alone did not result in reduced infarct size. clinicaltrials.gov Identifier: NCT00833612.
    JAMA The Journal of the American Medical Association 08/2011; 306(12):1329-37. · 29.98 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The primary objective of this report was to describe the infrastructures and processes of selected European and North American pre-hospital fibrinolysis (PHL) programs. A secondary objective is to report the outcome data of the PHL programs surveyed. Despite its benefit in reducing mortality in patients with ST-segment elevation myocardial infarction, PHL remained underused in North America. Examination of existing programs may provide insights to help address barriers to the implementation of PHL. The leading investigators of PHL research projects/national registries were invited to respond to a survey on the organization and outcomes of their affiliated PHL programs. PHL was successfully deployed in a wide range of geographic territories (Europe: France, Sweden, Vienna, England, and Wales; North America: Houston, Edmonton, and Nova Scotia) and was delivered by healthcare professionals of varying expertise. In-hospital major adverse outcomes were rare with mortality of 3% to 6%, reinfarction of 2% to 5%, and stroke of <2%. Combining formal protocols for PHL for some patients with direct transportation of others to a percutaneous coronary intervention hospital for primary percutaneous coronary intervention would allow for tailored reperfusion therapy for patients with ST-segment elevation myocardial infarction. Insights from a variety of international settings may promote widespread use of PHL and increase timely coronary reperfusion worldwide.
    JACC. Cardiovascular Interventions 08/2011; 4(8):877-83. · 1.07 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Despite advances in care processes to improve reperfusion in patients with acute myocardial infarction (AMI), the short-term and 1-year mortality remains high, in part, because of reperfusion injury, microvascular obstruction, and infarct expansion. Intraaortic balloon counterpulsation (IABC) is an adjunct to revascularization and has reduced microvascular obstruction and infarct size in animal models of AMI. CRISP AMI is a multicenter randomized trial that aims to determine if IABC initiated before percutaneous coronary intervention (PCI) for reperfusion compared with routine PCI in patients with anterior ST-segment elevation AMI reduces infarct size as measured by cardiac magnetic resonance imaging. Patients are randomly assigned to receive IABC initiated before primary PCI and continued for at least 12 hours or routine PCI with standard-of-care medical therapy in both groups. The primary efficacy end point is infarct size measured by cardiac magnetic resonance imaging at 3 to 5 days post-PCI. The secondary clinical end point is the composite of major adverse clinical events including death, reinfarction, and heart failure at 6 months. According to sample size calculation, 300 patients will be randomized at 50 sites across 10 countries. The CRISP AMI study will determine if IABC before reperfusion in patients with anterior AMI reduces infarct size.
    American heart journal 07/2011; 162(1):47-55.e1. · 4.65 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Currently accepted standards for gauging quality of care in the treatment of ST-segment elevation myocardial infarction (STEMI) mainly focus on shortening the time to treatment after the patient arrives at the hospital. But this narrow focus fails to consider the substantial duration of myocardial ischemia that exists prior to hospital arrival, and the large number of deaths that occur during the pre-hospital period. The time from symptom onset until reperfusion occurs is one estimate of total ischemic time. Several experimental studies and now human clinical studies have confirmed that infarct size and mortality are strongly correlated with the total ischemic time, and much less so with its subintervals like door-to-balloon time. This review will discuss the importance of total ischemic time in STEMI.
    JACC. Cardiovascular Interventions 06/2011; 4(6):599-604. · 1.07 Impact Factor

Publication Stats

3k Citations
952.41 Total Impact Points

Institutions

  • 2007–2013
    • University of Texas at Austin
      • Department of Biomedical Engineering
      Austin, Texas, United States
  • 1983–2013
    • University of Texas Medical School
      • • Department of Internal Medicine
      • • Department of Emergency Medicine
      • • Department of Pathology & Laboratory Medicine
      Houston, TX, United States
  • 1982–2013
    • University of Texas Health Science Center at Houston
      • • Division of Cardiovascular Medicine (Internal Medicine)
      • • Department of Internal Medicine
      • • Graduate School of Biomedical Sciences
      • • Medical School
      Houston, Texas, United States
  • 1994–2012
    • Texas Heart Institute
      Houston, Texas, United States
    • Georg-August-Universität Göttingen
      Göttingen, Lower Saxony, Germany
  • 2007–2011
    • University of Texas at Tyler
      Tyler, Texas, United States
  • 1999–2011
    • University of Houston
      Houston, Texas, United States
  • 2010
    • University of Virginia
      • Division of Pediatrics
      Charlottesville, Virginia, United States
  • 1986–2007
    • Memorial Hermann Hospital
      Houston, Texas, United States
  • 2006
    • Tel Aviv University
      Tell Afif, Tel Aviv, Israel
  • 2005
    • Houston Methodist Hospital
      Houston, Texas, United States
  • 1996
    • Universität Heidelberg
      • II. Medical Clinic
      Heidelberg, Baden-Wuerttemberg, Germany
  • 1985
    • Houston Zoo
      Houston, Texas, United States