bluuebunny/crossref_metadata_2025_split huggingface dataset:
Criticism of Cardiovascular Studies with Negative Results Due to a Negative Correlation
Authors: Cleophas Ton J. M. 
Published: July 2008

Background. Trials that do not allow rejection of the null hypothesis of no treatment effect may have had an inappropriate design. Self-controlled trials, although routinely used for the study of cardiovascular diseases, are virtually never assessed for correlation between treatment modalities. Methods. Using three models and a series of published studies as examples, the author studies the influence of correlation levels on the statistical power of self-controlled studies. Results. Between-subject variation as estimated by SD is largely dependent on the level of correlation, and so is the power of testing. The assessment of paired data as though they are unpaired can be used as a simple test to estimate correlation levels. Conclusion. It is extremely relevant to assess correlation levels in a paired comparison a priori. With a presumably negative correlation a self-controlled design is likely to lack power.
Morphologic Changes in Pulmonary Vasculature with Arteriographic Correlation
Authors: Basu Sabita , Datta B.N. , Khandelwal N. 
Published: July 2008

During fetal life the pulmonary circulation is one of high resistance. Soon after birth with the onset of breathing and thereafter, sequential structural changes in the pulmonary vasculature take place. Several authors have reported differently on this structural remodeling. This study describes the changes in the pulmonary vasculature occurring following birth. Twenty-five cases submitted to autopsy with ages ranging from newborns up to fourteen years were studied. Postmortem arteriography was undertaken in most of the cases and arterial morphology was quantitated by histomorphometry. It was found that the thick-walled pulmonary arteries of the newborn show a reduction in medial thickness over a period of one month, the reduction being most rapid in the first three days. After one month there is no significant change in medial thickness until fourteen years of age.
Morphologic and Histologic Characterization of Cardiac Myxomas by Magnetic Resonance Imaging
Authors: Matsuoka Hiroshi , Hamada Mareomi , Honda Toshio , Kawakami Hideo , Abe Mitsunori , Shigematsu Yuji , Sumimoto Takumi , Hiwada Kunio 
Published: July 2008

The purpose of this study was to assess the role of ECG-gated spin-echo (SE) magnetic resonance (MR) images, cine MR images, and gadolinium-diethylenetriaminepen taacetic acid (Gd-DTPA)-enhanced MR images for the morphologic and histologic diagnosis of atrial myxomas. Four patients with left atrial myxoma were imaged with a 1.5-T MR imager. The T1-weighted images and the cine MR images were obtained before injection of Gd- DTPA. After the injection of Gd-DTPA, the T1-weighted images were obtained again. Gd-DTPA-enhanced images of the myxomas were histologically compared with the extracted specimens. (continued on next page) The tumors were represented more clearly on the cine MR images as low-intensity areas than on the SE images as high-intensity areas. On post-Gd-DTPA images, the 2 tumors were homogeneously enhanced and the other 2 were inhomogeneously enhanced. The locus of enhancement on post-Gd-DTPA images fitted with histologic myxoma or inflammation, and the unenhanced region reflected the necrosis or cystic changes in the specimens, respectively. The morphologic diagnosis of cardiac myxomas by MRI first should be done with SE images, and when the images are unclear, the cine MR images must be supplemented to depict the tumor clearly. Moreover, Gd-DTPA-enhanced MRI could elucidate histo logic characteristics in myxomas.
The Influence of Different AV Delays on Left Ventricular Diastolic Functions and on Incidence of Diastolic Mitral Regurgitation
Authors: Postaci Nursen , Yeşil Murat , Susam Ibrahim , Bayata Serdar 
Published: July 2008

In patients with a DDD pacemaker (PM), programming of atrioventricular (AV) delay can influence ventricular filling and function. In this study the authors used color Doppler echocardiography to evaluate the effect of different AV delays on left ventricular diastolic function (LVDF) and on the incidence of diastolic mitral regurgitation. In 26 patients with DDD PM, the following parameters were evaluated during five different AV delays by echocardiography: (1) mitral E wave amplitude (by pulsed Doppler), (2) mitral A wave amplitude (by pulsed Doppler), (3) isovolumetric relaxation time (IVRT), (4) deceleration time (DT), (5) LV diastolic dimension (LVDd), (6) LV systolic dimension (LVDs), (7) ejection fraction (EF), and (8) diastolic mitral regurgita tion (DMR). Patients had been paced for symptomatic AV block (n: 16, 62%) and sick sinus syndrome (n: 10, 38%). Mean age of patients was fifty-two (nineteen to sixty- three) and 13 (50%) of them were women. (continued on next page) Correlation was sought between AV delay and investigated parameters. The correla tion coefficients of AV delay and E wave, A wave, IVRT, DT, LVDd, LVDs, and EF were -0.137, 0.243, 0.541, 0.031, 0.210, 0.241, and -0.184 respectively. DMR was detected in all cases when AV delay was increased more than 150 msec. In conclusion, a slight correlation was found between AV delay and IVRT (r: 0.541). Other parameters of LV diastolic and systolic function did not correlate with AV delay. Second, DMR was observed in all patients when the AV delay was prolonged more than 150 msec.
Detection of Myocardial Viability in the Prediction of Improvement in Left Ventricular Function After Successful Coronary Revascularization by Using the Dobutamine Stress Echocardiography and Quantitative SPECT Rest-Redistribution-Reinjection 201TI Imaging After Dipyridamole Infusion
Authors: Kostopoulos Konstantinos G. , Kranidis Athanasios I. , Bouki Konstantina P. , Antonellis John P. , Kappos Kostas G. , Rodogianni Fivi E. , Zamanis Nikolaos J. , Tavernarakis Anthony G. , Lolas Christos T. , Anthopoulos Lambros P. 
Published: July 2008

The aim of this study was to assess the feasibility, safety, and respective diagnostic accuracy of low-dose dobutamine infusion and rest-redistribution-reinjection thallium 201 single photon emission computed tomography (SPECT) after dipyridamole infusion (Th-DIP), in the prediction of functional improvement of asynergic infarcted zones, after successful revascularization in patients with chronic ischemic heart disease. Thirty-one patients with a previous myocardial infarction and left ventricular dysfunction (mean ejection fraction: 41 ±5.8%) were studied. The regional wall motion of the left ventricle was evaluated by basic echocardiography before and 14 ± 1.7 weeks after successful revascularization (19 by percutaneous transluminal coronary angioplasty and 12 by coronary artery bypass grafting). Dobutamine stress echocardiography (DSE) was performed in all patients with dobutamine infusion of 5 and 10 μg/kg/minute over five minutes. Within three days after DSE and prior to revascularization, all patients underwent Th-DIP for myocardial viability assessment. A 16-ventricular-segment model was used for basic, DSE, and Th-DIP images. Viability was assessed by applying the (continued on next page) standard criteria for each technique. In the 31 patients, 496 segments were analyzed. By basic echocardiography, 164 (33%) of them were classified as asynergic. The DSE detected viable tissue in 69/496 (14%) segments, whereas Th-DIP identified viability in 95/496 (19%) segments. When the postrevascularization basic echocardiographic study was used as the gold standard in identifying myocardial viability, the sensitivity and specificity for the DSE and Th-DIP were 86.5%, 94.4% and 90.5%, 69%, respectively. No major side effects were observed with both techniques. In conclusion, DSE seems to be an accurate method for identifying viable but asynergic myocardium in patients with chronic ischemic heart disease, whereas Th-DIP overestimates the postrevascularization recovery. Detection of hibernating myocardium can be obtained by these two noninvasive methods. However, DSE seems to be more useful in determining the prospective selection of patients who are going to benefit from revascularization.
Quantitative Assessment of Coronary Atherosclerotic Plaque Profile by Morphometric Analysis of Angiographic Images
Authors: Palmieri Cataldo , Sicari Marco Paterni Rosa , Picano Eugenio , Biagini Andrea , Marzilli Mario 
Published: July 2008

Coronary plaque morphology (simple or complex) has a recognized clinical, pathophys iologic, and prognostic importance, but its routine use is hampered by the subjective and qualitative nature of the assessment. The aim of this study was to assess the feasibility and accuracy of mathematical, objective, operator-independent assessment of plaque morphology, by means of algorithms based on vector and fractal analysis, previously developed for describing continuous curves. Twenty coronary angiograms were analyzed: 10 with "simple-type" stenosis (defined according to Ambrose type I pattern, Group I) and 10 with "complex-type" stenosis (Ambrose type II pattern, Group II). Five morphometric parameters effectively separated simple and complex-type stenosis: peaks/cm (Group I = 0.24 ±0.31 vs Group II= 2.46 ± 1.83, P < .01); summed maximum error/cm (I = 0.94 ±1.19 vs II = 4.53 ±0.56, P < .01); integrated error/cm (I = 0.22 ±0.27 vs II = 2.25 ± 1.68, P < .01); number of features/cm (I = 0.02 ±0.05 vs II = 1.19 ±0.65, P < .01); standard deviation curvature (I = 0.07 ±0.01 vs II = 0.22 ±0.21, P = 0.06). The scaled edge-length ratio—the only parameter based on fractal analysis—was not different between the two groups (I = 1.03 ±0.01 vs II = 1.13 ±0.10, P = ns). Hence, a quantitative description of plaque morphology is feasible and allows an effective discrimination of simple and complex plaque profiles with morphometric para meters based on vector analysis.
Effects of Morphologic Restenosis, Defined by MRI After Coarctation Repair, on Blood Pressure and Arm-Leg and Doppler Gradients
Authors: Günthard Joëlle , Buser Peter T. , Miettunen Risto , Hagmann Andreas , Wyler Felix 
Published: July 2008

Ten years after coarctation repair, 36 adolescents and young adults were studied in order to evaluate the relationship of anatomy at the resection site to blood pressure and arm- leg and Doppler gradients. The patients underwent magnetic resonance imaging (MRI), exercise testing, and continuous wave (CW) Doppler echocardiography. On MRI, residual narrowing at the resection site was measured as 1-(ø anastomosis/ ø descending aorta) and expressed as percent stenosis. Residual stenosis on MRI was negatively correlated with the leg pressure at rest (P=0.0003) and during exercise (P=0.002). Residual stenosis correlated positively with the arm-leg gradient at rest (P<0.0001) and during exercise (P<0.0001) and with the peak CW Doppler gradient across the anastomosis (P<0.0001). However, residual stenosis was not related to the systolic blood pressure of the arm at rest or during exercise. The systolic arm pressures did not differ between patients with residual stenosis of less than 30% (group I), patients with residual stenosis of equal to or greater than 30% but less than 45% (group II), and patients with residual stenosis of equal to or greater than 45% (group III). In conclusion residual anatomic stenosis influences blood pressure in the legs, the arm-leg gradient, and the Doppler gradient across the anastomosis. Arm hypertension late after coarctation repair seems not to be related to residual stenosis, and the benefit of reintervention in these patients remains questionable.
Cardiovascular Risk Factors in Commercial Flight Aircrew Officers Compared with Those in the General Population
Authors: Ekstrand Karin , Boström Per-Ake , Arborelius Måns , Nilsson Jan-Åke , Lindell Sven-Eric 
Published: July 2008

Cardiovascular disease is the most common reason for loss of license among commercial flight pilots. This study was done to explore cardiovascular risk factors among aircrew officers. The study group consisted of 113 male commercial flight aircrew officers (aviators), aged thirty-five to forty-four years (mean: 38.8 years) who participated in the compulsory health screening. Men investigated at the Health Screening Centre, Malmö, were used as the reference group. Group 1, for ECG, (n 771), aged thirty-eight to forty-four years (mean: 42.1). Group 2, for height, weight, body mass index (BMI) (weight kg/height m 2), blood pressure, serum cholesterol (total), and smoking habits (n 5005), aged thirty-five to forty-four years (mean: 39.2). The aviators did not differ from the reference population in regard to height, weight, BMI, diastolic blood pressure, or smoking habits. However, the incidences of electrocar diographic left ventricular hypertrophy, increased systolic blood pressure, and the level of cholesterol were significantly higher in the aviators when compared with the controls. Aircrew members may primarily be selected by criteria that differ from the male popu lation in general. Excessive environmental stress, ie, shift work, jet lag, fatigue, as well as dietary factors, may also contribute to anomalies in the group. The clinical consequences of these anomalies for the aviators should be further evaluated, for they are important both for the aviators and for flying safety.
Portal Vein Obstruction Accompanied by Intrahepatic Stones
Authors: Tanaka Koki , Komokata Teruo , Ikoma Akira , Yamaoka Akihiro , Fukumoto Yoshihiro , Taira Akira 
Published: July 2008

This study was conducted to clarify the pathogenesis of portal vein obstruction (PVO) associated with intrahepatic stones. Five cases with PVO and intrahepatic stones were studied retrospectively. The coincidence rate of PVO in intrahepatic stones was 5.8% (5 of 86 cases), and that of intrahepatic stones in PVO, 45.5% (5 of 11 cases). All cases had one or more symptoms of cholangitis, such as high-grade fever, abdominal pain, and jaundice prior to diagnosis of PVO. The portal vein was occluded at the main trunk in 4 and in the left branch in 1. Intrahepatic stones were found in bilateral hepatic lobes in 3 and in the left lobe in 2. Numerous calcium bilirubinate stones were packed in dilatated intrahepatic bile ducts of an excised specimen of the liver. Microscopically, arterial structures could be seen, but the portal vein ceased to be evident about the involved bile duct. Based on the results of this study, persistent cholangitis and packed gallstones were concluded essential to the development of PVO accompanied by intrahepatic stones.
Hemodynamic Consequences of Stenosis Remodeling During Coronary Angioplasty
Authors: Back Martin R. , White Rodney A. , Kwack Eug Y. , Back Lloyd H. 
Published: July 2008

Quantitative hemodynamic assessment during various endovascular interventions including balloon angioplasty is lacking. Translesional pressure drops measured by angio plasty catheters can cause flow blockage and thus lead to inaccurate estimates of prein tervention and postintervention flow rates. A new analytical model of the flow rate- pressure drop relation across vascular stenoses is utilized that is nonlinear yet relatively simple in principle, easily applicable in vivo, and compatible with the presence of catheters. The model incorporates in vitro experimental evidence, angiographic data on the dimensions and shapes of coronary arterial stenoses before and after balloon angio plasty, reported translesional pressure gradients, and measurements of coronary flow reserve. Reasonable estimates of mean coronary artery flow rates and translesional pressure drops in the absence of angioplasty catheters are obtained. Prior to angioplasty significant flow restriction across a 68% diameter stenosis exists during hyperemic flow conditions. Following successful balloon dilation, increased minimal cross-sectional area (residual 40% diameter stenosis) results in an improved flow rate-pressure drop relation. Despite minimal flow restriction during hyperemic conditions following angioplasty remodeling, residual luminal constriction leads to elevated wall shear stress levels within the entry region of the stenosis. The flow analysis described may be of clinical utility in evaluating the hemodynamic significance of the anatomic severity of stenoses in coronary and peripheral arteries before and after endovascular therapeutic interventions.
Effect of Calcium Channel Blockade on Skin Blood Flow in Diabetic Hypertension: A Comparison of Isradipine and Atenolol
Authors: Rendell Marc S. , Shehan Mary Ann , Kahler Kennis , Bailey Kristina L. , Eckermann August J. , Rendell Marc S. 
Published: July 2008

In previous studies, using laser Doppler techniques, the authors have demonstrated a duration-dependent reduction in skin blood flow reserve at sites of nutritive (NUTR) perfusion that occurs in diabetes and correlates with the presence of diabetic retinopathy and proteinuria. They speculated that it might be possible to reverse this decrease in blood flow by using agents with peripheral vasodilating properties. They chose the calcium channel blocking agent isradipine as a prototype. As a contrast agent, they chose atenolol, which has an equivalent antihypertensive effect but minimal peripheral vasodi lating properties. They studied 24 diabetic hypertensive patients in a randomized, two-way crossover design. They assigned patients randomly to one or the other active drug and titrated to a maximum tolerated maintenance dose. Skin blood flow was measured at the end of the titration and maintenance phases. Patients then entered a four-week washout period, followed by crossover to the alternative drug, and measurements were repeated. At baseline, the twenty-four-hour mean ambulatory systolic blood pressure was 150 ±2 mm Hg with a twenty-four-hour mean diastolic blood pressure of 93 ±1 mm Hg. Thermally stimulated skin blood flow reserve was about 50% lower in these patients as compared with an age-, sex-, and weight-matched group of 28 nondiabetic, nonhyper tensive patients. There was no difference in skin blood flow between the two groups at basal skin temperature or at a controlled temperature of 35°C. Both atenolol and isradipine successfully lowered blood pressure in the study patients. There was a slightly greater decrease in systolic blood pressure with isradipine and a greater decrease in heart rate with atenolol. Neither isradipine nor atenolol treatment affected skin blood flow values at the maximal 44°C temperature. However, at basal skin temperature and at 35°C, isradipine-treated patients had substantial increases in skin blood flow at NUTR sites. For example, skin blood flow at the knee at 35°C with isradipine treatment was 3.1 ±0.4 mL/min/100 g compared with 1.1 ±0.2 with atenolol, 1.3 ±0.1 with placebo, and 0.9 ±0.1 for the nondiabetic controls (all P<0.01). The authors found a twofold to threefold increase in basal skin blood flow at NUTR sites with isradipine treatment. This degree of increase is substantially greater than that previously demonstrated by their group using pentoxifylline. Locally reduced skin blood flow is a factor in promoting skin breakdown and delayed healing. Further study is needed to explore the possibility that isradipine treatment may enhance healing of diabetic skin ulcers.
Epidemiology and Costs of Venous Diseases in Central Italy
Authors: Cesarone M.R. , Belcaro G. , Nicolaides A.N. , Laurora G. , De Sanctis M.T. , Incandela L. , Barsotti A. , Belcaro G. 
Published: July 2008

The Prevalence of Early Atherosclerosis study aims to define the prevalence of subclinical atherosclerosis in a typical population of central Italy. A concomitant study evaluates the prevalence of venous diseases. The prevalence of superficial and deep venous disease, the prevalence of venous thrombosis and pulmonary embolism, and the prevalence of the most common venous malformations were studied through use of medical history, a questionnaire, and noninvasive investigations. The costs of venous problems were also considered. Of some 2000 inhabitants, 746 (379 women; mean age 46.3 ±7 years; range eight to nienty-four) have been screened. No significant difference in trend increase of the rela tionship age/percent of subjects with venous problems was observed for superficial venous disease. The increase in the proportion of subjects with lipodermatosclerosis and venous ulcerations appeared to be correlated with age (r=0.543). Evidence accepted for pulmonary embolisms was pulmonary angiogram or evidence on ventilation+perfusion lung scans. According to these criteria the number of documented deep vein thromboses and pulmonary embolisms was very limited with a larger number of suspected disease entities. There was no significant correlation between age and pulmonary embolism or deep venous thrombosis distribution. The number of venous and/or arteriovenous malfor mations was comparable along the age axis in the different age groups. Only a limited number of these malformations (in less that 1% of subjects) had caused a clinical problem. The treatments used for venous problems have been reported in a question naire and subdivided into occasional treatments and chronic treatments (when used for periods longer than twelve months). The percent of subjects using different treatment was also studied. Treatments were divided in: (1) over-the-counter products (or any treatment not requiring prescription); (2) specialized drug (for venous diseases); (3) compression; (4) surgery (any type of surgical treatment); (5) sclerotherapy; (6) combined treatments (ie, sclerotherapy and surgery); (7) alternative treatments (herbal products etc). Finally, the average costs per year for treatment, for investigations, and the costs due to lost working days were recorded. In conclusion some 12% of the evaluated population sample (male population 46%) had or had been affected in the past by a venous problem and 50% of them had received some type of treatment.
Comparison of Multiple-Dose and Once-Daily Nitrate Therapy in 1212 Patients with Stable Angina Pectoris: Effects on Quality of Life Indices
Authors: Niemeyer Menco G. , Kleinjans Huub A. J. , de Ree Rob , Zwinderman Aeilko H. , Cleophas Ton J. M. , van der Wall Ernst E. , Cleophas A.J.M. ,   Dutch Mononitrate Quality of Life Study Group
Published: July 2008

Background: Nitrates, although important for the management of anginal symptoms, produce significant side effects. Little is known about their net effects on health-related, quality-of-life indices. Methods: In a self-controlled, 6-month study, the effects on symptoms and quality of life of multiple-dose and once-daily nitrate therapy were evaluated in 1212 patients with stable angina pectoris. Quality of life was assessed by a test battery based on the exercise- tolerance index of Wiklund, the psychological well-being index of Dupuy, and the Short Form 36 questionnaire of Stewart. The internal consistency and reliability of the multi- item scales were estimated by Cronbach's alpha coefficients. Results: The effects of the two treatment regimens on pain index and number of addi tional sublingual nitrate tablets required were not different. However, based on the New York Heart Association (NYHA) angina classification, patients improved better on the once-daily than on the multiple-dose regimen: by > 1 category in 281 vs 62 of the patients (P<0.0001) ; mobility and psychological distress indices also improved (P = 0.006, and P=0.007). Conclusions: Once-daily nitrate therapy not only provides a better NYHA angina classifi cation than multiple-dose therapy does, but also provides a better quality of life as estimated by improvement of mobility and distress indices, the most important indicators of quality of life in this category of patients.