Degree Of Coronary Occlusion Research Articles

Association between Monitor and Satellite-Based Estimates of Long-term Air Pollution Exposure and Degree of Coronary Occlusion

Introduction: Cardiovascular events have been linked with air pollution exposure, though most studies have used data from air quality monitors. Satellite-based predictions may more accurately predict exposure concentrations over purely monitored data, though few studies have compared results from both exposure assessment methods. Methods: We utilized a cohort of 5679 patients who had undergone a cardiac catheterization at Duke University between 2002-2009 and resided in NC. Exposure to PM2.5 was estimated using data from a) air quality monitors, b) 10km satellite-based models combined with monitored data, c) 1km satellite-based models that incorporate land use terms, meteorological variables, and monitored data, and d) 1km hybrid models that combine satellite data, GEOS-Chem predictions, monitored data, land use terms, and meteorological variables. PM2.5 predictions were matched to each patient’s address and averaged for the year prior to catheterization. The coronary artery disease (CAD) index was used to measure severity of CAD, and individuals with an index >23 were considered positive cases. Logistic regression was used to model odds of having CAD with each 1-unit (μg/m3) increase in annual average PM2.5, adjusting for gender, race, smoking status and socioeconomic status. Results: Positive associations were seen across all metrics, most significantly for the more spatially resolved 10km and 1km PM2.5 estimates. Specifically, we found a 3% (95%CI: 0.98-1.08) increase in the odds of significant CAD for each 1 μg/m3 increase in PM2.5 when using monitored estimates, 11% (95%CI: 1.04-1.19) increase for 10km PM2.5 estimates, 14% (95%CI: 1.07, 1.21) increase for 1km estimates, and 6% (95%CI: 1.00-1.12) increase for 1km hybrid estimates. Conclusions: Long-term air pollution exposure was associated with coronary artery disease for both satellite modeled and monitored data. This abstract does not necessarily reflect U.S. EPA policy.

Dynamic Myocardial Perfusion in a Porcine Balloon-induced Ischemia Model using a Prototype Spectral Detector CT.

Myocardial CT perfusion (CTP) imaging is an application that should greatly benefit from spectral CT through the significant reduction of beam hardening (BH) artifacts using mono-energetic (monoE) image reconstructions. We used a prototype spectral detector CT (SDCT) scanner (Philips Healthcare) and developed advanced processing tools (registration, segmentation, and deconvolution-based flow estimation) for quantitative myocardial CTP in a porcine ischemia model with different degrees of coronary occlusion using a balloon catheter. The occlusion severity was adjusted with fractional flow reserve (FFR) measurements. The SDCT scanner is a single source, dual-layer detector system, which allows simultaneous acquisitions of low and high energy projections, hence enabling accurate projection-based material decomposition and effective reduction of BH-artifacts. In addition, the SDCT scanner eliminates partial scan artifacts with fast (0.27s), full gantry rotation acquisitions. We acquired CTP data under different hemodynamic conditions and reconstructed conventional 120kVp images and projection-based monoenergetic (monoE) images for energies ranging from 55keV-to-120keV. We computed and compared myocardial blood flow (MBF) between different reconstructions. With balloon completely deflated (FFR=1), we compared the mean attenuation in a myocardial region of interest before iodine arrival and at peak iodine enhancement in the left ventricle (LV), and we found that monoE images at 70keV effectively minimized the difference in attenuation, due to BH, to less than 1 HU compared to 14 HU with conventional 120kVp images. Flow maps under baseline condition (FFR=1) were more uniform throughout the myocardial wall at 70keV, whereas with 120kVp data about 12% reduction in blood flow was noticed on BH-hypoattenuated areas compared to other myocardial regions. We compared MBF maps at different keVs under an ischemic condition (FFR < 0.7), and we found that flow-contrast-to-noise-ratio (CNR f ) between LAD ischemic and remote healthy territories attains its maximum (2.87 ± 0.7) at 70keV. As energies diverge from 70keV, we noticed a steady decrease in CNRf and an overestimation of mean-MBF. Flow overestimation was also noticed for conventional 120kVp images in different myocardial regions.

Satellite-Based Estimates of Long-Term PM2.5 Exposure Are Associated with Degree of Coronary Occlusion

Satellite-Based Estimates of Long-Term PM2.5 Exposure Are Associated with Degree of Coronary OcclusionAbstract Number:2056 Laura McGuinn*, Cavin Ward-Caviness, William Kraus, Elizabeth Hauser, Alexandra Chudnovsky, Petros Koutrakis, David Diaz-Sanchez, Lucas Neas, and Robert Devlin Laura McGuinn* University of North Carolina at Chapel Hill, United States, E-mail Address: [email protected] Search for more papers by this author , Cavin Ward-Caviness Duke University, United States Search for more papers by this author , William Kraus Duke University, United States Search for more papers by this author , Elizabeth Hauser Duke University , United States Search for more papers by this author , Alexandra Chudnovsky Harvard School of Public Health, United States Search for more papers by this author , Petros Koutrakis Harvard School of Public Health, United States Search for more papers by this author , David Diaz-Sanchez U.S. Environmental Protection Agency, United States Search for more papers by this author , Lucas Neas U.S. Environmental Protection Agency, United States Search for more papers by this author , and Robert Devlin U.S. Environmental Protection Agency, United States Search for more papers by this author AbstractBackground: Epidemiological studies have found associations between both short and long-term PM2.5 exposure and cardiovascular events, though many have relied on data from central-site air quality monitors.Objectives: We examined the associations between long-term PM2.5 exposure and coronary artery disease (CAD) in a cardiac catheterization cohort in North Carolina.Methods: We utilized a cohort of 5069 patients who had undergone cardiac catheterization at Duke University between 2002-2009 and resided in North Carolina. We used temporally and spatially (10 by 10 km) resolved estimates of daily PM2.5 concentrations from 2002-2009 for North Carolina based on satellite derived aerosol optical depth measurements, monitored data and land use. PM2.5 predictions were matched to each patient’s address and averaged for the year prior to catheterization. The CAD index was used to measure severity of CAD, and individuals with an index >23 were considered cases because they represent a population with hemodynamically significant lesions. Logistic regression was used to model odds of having CAD or a myocardial infarction (MI) with each unit increase in annual average PM2.5. Odds ratios (OR) and 95% confidence intervals (CI) were calculated per unit (µg/m3) increase in PM2.5, adjusting for gender, race, smoking status and socioeconomic status.Results: There were a total of 3411 people with CAD, 2491 with a CAD index >23 and 581 that had experienced a recent MI. The interquartile range for annual average PM2.5 was 0.78 (µg/m3). In adjusted models, a 1 µg/m3 increase in PM2.5 was associated with a 10.9% increase in the odds of CAD (95% CI: 3.7%-18.5%) and a 12.2% increase in the odds of having a recent MI (95% CI: 0.0%-25.7%).Conclusions: Long-term PM2.5 exposure was associated with both coronary artery disease and incidence of myocardial infarction in a well-characterized cohort of cardiac catheterization patients. This abstract does not necessarily reflect U.S. EPA policy.

The relationship between severity of coronary artery disease and plasma level of vascular endothelial growth factor

It has been known that ischemia or occlusion of coronary arteries in animal models increases the production of vascular endothelial growth factor (VEGF); however, little is known about the relationship between coronary artery disease and VEGF in humans. In this study, our aim was to evaluate the relationships between the degree of coronary occlusion and plasma VEGF level as well as other risk factors, including age, weight, arterial blood pressure, cholesterol, triglyceride, blood glucose, and high-sensitive C-reactive protein (hsCRP) in patients with established coronary artery disease. Our study group consisted of 77 patients. Of these, 38 patients had normal coronary angiography (control group; group C) and 39 had abnormal angiography (17 critical lesion; group CL, 22 noncritical lesion; non-CL group). Plasma VEGF level was 116.95+/-30.12 pg/ml in the control group, 212.47+/-75.28 pg/ml in group CL, and 138.89+/-45.18 pg/ml in the non-CL group. Plasma VEGF level of group C was found to be lower than that of group CL (P<.05), but the difference between groups C and non-CL was insignificant (P>.05). However, logistic regression analysis showed that VEGF level of group CL was significantly higher (P<.001). There was a negative correlation between VEGF and haemoglobin (r=-0.58, P<.01), and positive correlation between VEGF and age (r=0.29, P<.04). There was no relationship between plasma VEGF level and other cardiac risk parameters. Group CL had a higher level of total and LDL-cholesterol levels. Increased plasma VEGF levels in patients with coronary artery disease may point that the coronary lesion is critical, and VEGF increase in patients with established coronary artery disease may be used as an indicator of the need for revascularization.

Variable effects of intracoronary nitroglycerin on myocardial blood flow and segmental shortening according to dose and degree of coronary occlusion

The effects of intracoronary nitroglycerin were determined in 21 open-chest dogs. Six dogs with severe stenosis (25 mm Hg diastolic perfusion pressure) and nine dogs with moderate stenosis (40 mm Hg) received a 12 μg bolus followed by 44 μg/min intracoronary nitroglycerin. In addition, six dogs with moderate stenosis (40 mm Hg) received 5 μg followed by 5 μg/min nitroglycerin. Myocardial blood flow was measured with radioactive microspheres and segment shortening with ultrasonic crystals. At 40 mm Hg, high-dose but not low-dose nitroglycerin raised epicardial blood flow, while at 25 mm Hg nitroglycerin had no effect. Subendocardial blood flow was not affected in any group. Partial occlusion resulted in a decrease in segment shortening in the 25 mm Hg group but not at 40 mm Hg. High-dose nitroglycerin had no effect on shortening at either level of occlusion. Thus, in the presence of coronary vascular reserve, high-dose nitroglycerin may overcome coronary autoregulation. A dose equivalent to one that simulates the amount of nitroglycerin delivered to the coronary circulation by a systemic infusion did not affect myocardial blood flow. In addition, even a large dose of nitroglycerin did not affect segment shortening.

Asynergy in Coronary Heart Disease

The widespread use of cardiac ventriculography has focused interest on the frequency with which asynergy accompanies coronary heart disease as well as on its clinical and prognostic implications and dynamic nature. Recently, "intervention ventriculography" using nitroglycerin or postextrasystolic potentiation has indicated that asynergic zones may be more accurately classified as reversible (implying viable myocardium) or irreversible (nonviable or scarred myocardium), and thus the ventriculographic definition of aneurysm must reflect not only the severity of asynergy but its contractile reserve. Surface electrocardiogram Q waves, the severity of asynergy, and degree of coronary occlusion all adversely affect the potential for reversibility, whereas coronary collaterals enhance it. Important clinical applications include assessment of the potential utility of coronary bypass surgery in improving asynergy and of vasodilators in the treatment of patients with left ventricular failure. With refractory sequelae of aneurysms (heart failure, ventricular tachyarrhythmias, and systemic emboli) and a discrete aneurysm, surgical resection has been increasingly used with generally good results.

Soluble fibrin complexes in coronary disease

The occurrence of intravascular coagulation in coronary artery disease was evaluated by measurement of soluble fibrin complexes (SFC). Using 4% agarose and a long column it was possible to quantify by gel filtration the SFC including high molecular weight fibrinogen derivatives and to separate them from fibrinogen, and fibrinogen degradation products. Of 21 patients with chest pain undergoing coronary angiography, 16 patients with one or more coronary arteries significantly occluded on angiogram showed a marked increase in percent SFC (23.3 ± 3.5 SEM) while 5 individuals with chest pain and normal angiograms had only 10.9 ± 2.0% SFC. In contrast, 6 normal individuals had only 4.6 ± 1.3% of their fibrinogen in the form of SFC. A modest correlation was demonstrated between levels of SFC and degree of coronary occlusion which probably reflects the generalized atherosclerosis in these patients. Serum fibrinogen degradation products (FDP) in the patients' sera as assayed by staphlococcal clumping test were found to be moderately elevated only in patients with abnormal angiograms. The role of the intrinsic coagulation pathway was evaluated by assays of prekallikrein (preK), kallikrein inhibitors (KI) and determinations of inactive Hageman factor (factor XII). No significant changes were found in the two groups of patients when compared to normal suggesting that activation of the intrinsic pathway was not involved.