Variability in meta-analytic results concerning the value of cholesterol reduction in coronary heart disease: a meta-meta-analysis.
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Despite official support for the efficacy of cholesterol reduction, considerable controversy exists, and meta-analyses of this topic have produced conflicting results. The authors assessed the variability of meta-analyses, evaluating the cardiovascular value of cholesterol reduction while attempting to explain the variability. Metaanalyses were identified by electronic search and citation tracking. Included were those conducted prior to 1995 that dealt with cholesterol reduction and total mortality, cardiovascular mortality, or nonfatal cardiovascular disease. In addition to extracting odds ratios for total mortality, cardiovascular mortality, and nonfatal cardiovascular disease, the authors encoded methodological variables, publication variables, and data concerning investigators' backgrounds. Twenty-three meta-analyses were reviewed, and 15 concluded that cholesterol reduction was beneficial. Summary odds ratios for total mortality were heterogeneous, generally failing to support the value of cholesterol reduction. Odds ratios depended on inclusion criteria and investigator variables. Odds ratios for cardiovascular mortality and for nonfatal cardiovascular disease were more homogeneous and supported the value of cholesterol reduction. Methodologically better meta-analyses tended to report more beneficial odds ratios. Although "supportiveness" of the value of cholesterol reduction was associated with inclusion/exclusion criteria and publication variables, the primary outcome variable related to supportiveness was the statistical significance of the odds ratios for cardiovascular mortality. (+info)
Radiolucent lines and component stability in knee arthroplasty. Standard versus fluoroscopically-assisted radiographs.
(10/5805)
The radiolucent lines and the stability of the components of 66 knee arthroplasties were assessed by six orthopaedic surgeons on conventional anteroposterior and lateral radiographs and on fluoroscopic views which had been taken on the same day. The examiners were blinded as to the patients and clinical results. The interpretation of the radiographs was repeated after five months. On fluoroscopically-assisted radiographs four of the six examiners identified significantly more radiolucent lines for the femoral component (p < 0.05) and one significantly more for the tibial implant. Five examiners rated more femoral components as radiologically loose on fluoroscopically-assisted radiographs (p = 0.0008 to 0.0154), but none did so for the tibial components. The mean intra- and interobserver kappa values were higher for fluoroscopically-assisted radiographs for both components. We have shown that fluoroscopically-assisted radiographs allow more reproducible, and therefore reliable, detection of radiolucent lines in total knee arthroplasty. Assessment of the stability of the components is significantly influenced by the radiological technique used. Conventional radiographs are not adequate for evaluation of the stability of total knee arthroplasty and should be replaced by fluoroscopically-assisted films. (+info)
Plaque area increase and vascular remodeling contribute to lumen area change after percutaneous transluminal angioplasty of the femoropopliteal artery: an intravascular ultrasound study.
(11/5805)
OBJECTIVE: The aim of the study was to assess the change in lumen area (LA), plaque area (PLA), and vessel area (VA) after percutaneous transluminal angioplasty (PTA) of the femoropopliteal artery. METHODS: This was a prospective study. Twenty patients were studied with intravascular ultrasound (IVUS) immediately after PTA and at follow-up examination. Multiple corresponding IVUS cross-sections were analyzed at the segments that were dilated by PTA (ie, treated sites; n = 168), including the most stenotic site (n = 20) and the nondilated segments (ie, reference sites; n = 77). RESULTS: At follow-up examination, both the PLA increase (13%) and the VA decrease (9%) resulted in a significant LA decrease (43%) at the most stenotic sites (P =.001). At the treated sites, the LA decrease (15%) was smaller and was caused by the PLA increase (15%). At the reference sites, the PLA increase (15%) and the VA increase (6%) resulted in a slight LA decrease (3%). An analysis of the IVUS cross-sections that were grouped according to LA change (difference >/=10%) revealed a similar PLA increase in all the groups: the type of vascular remodeling (VA decrease, no change, or increase) determined the LA change. At the treated sites, the LA change and the VA change correlated closely (r = 0.77, P <.001). At the treated sites, significantly more PLA increase was seen in the IVUS cross-sections that showed hard lesion or media rupture (P <.05). No relationship was found between the presence of dissection and the quantitative changes. CONCLUSION: At the most stenotic sites, lumen narrowing was caused by plaque increase and vessel shrinkage. Both the treated sites and the reference sites showed a significant PLA increase: the type of vascular remodeling determined the LA change at follow-up examination. The extent of the PLA increase was significantly larger in the IVUS cross-sections that showed hard lesion or media rupture. (+info)
Iron supplemented formula milk related to reduction in psychomotor decline in infants from inner city areas: randomised study.
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OBJECTIVE: To compare the effect of unmodified cows' milk and iron supplemented formula milk on psychomotor development in infants from inner city areas when used as the main milk source. DESIGN: Double blind, randomised intervention trial. SETTING: Birmingham health centre. SUBJECTS: 100 infants, mean age 7.8 months (range 5.7 to 8.6 months), whose mothers had already elected to use unmodified cows' milk as their infant's milk source. INTERVENTION: Changing to an iron supplemented formula milk from enrolment to 18 months of age, or continuing with unmodified cows' milk. MAIN OUTCOME MEASURES: Developmental assessments using Griffiths scales at enrolment and at 18 and 24 months. RESULTS: 85 participants completed the trial. There were no significant differences in haemoglobin concentration between the two groups at enrolment, but by 18 months of age 33% of the unmodified cows' milk group, but only 2% of the iron supplemented group, were anaemic (P<0.001). The experimental groups had Griffiths general quotient scores that were not significantly different at enrolment, but the scores in both groups declined during the study. By 24 months the decrease in the mean scores in the unmodified cows' milk group was 14.7 whereas the decrease in the mean scores in the iron supplemented group was 9.3 (P<0.02, 95% confidence interval 0.4 to 10.4). Mean subquotient scores were considerably lower in the unmodified cows' milk group at 24 months; significantly so for personal and social scores (P<0.02, 1.2 to 16.8 [corrected]). CONCLUSION: Replacing unmodified cows' milk with an iron supplemented formula milk up to 18 months of age in infants from inner city areas prevents iron deficiency anaemia and reduces the decline in psychomotor development seen in such infants from the second half of the first year. (+info)
Recovery of contractility of viable myocardium during inotropic stimulation is not dependent on an increase of myocardial blood flow in the absence of collateral filling.
(13/5805)
OBJECTIVES: The purpose of this study was to determine whether contractile recovery induced by dobutamine in dysfunctioning viable myocardium supplied by nearly occluded vessels is related to an increase in blood flow in the absence of collaterals. BACKGROUND: Dobutamine is used to improve contractility in ventricular dysfunction during acute myocardial infarction. However, it is unclear whether a significant increase in regional blood flow may be involved in dobutamine effect. METHODS: Twenty patients with 5- to 10-day old anterior infarction and > or =90% left anterior descending coronary artery stenosis underwent 99mTc-Sestamibi tomography (to assess myocardial perfusion) at rest and during low dose (5 to 10 microg/kg/min) dobutamine echocardiography. Rest echocardiography and scintigraphy were repeated >1 month after revascularization. Nine patients had collaterals to the infarcted territory (group A), and 11 did not (group B). RESULTS: Baseline wall motion score was similar in both groups (score 15.9+/-1.3 vs. 17.4+/-2.0, p = NS), whereas significant changes at dobutamine and postrevascularization studies were detected (F[2,30] = 409.79, p < 0.0001). Wall motion score improved significantly (p < 0.001) in group A both at dobutamine (-5.3+/-2.2) and at postrevascularization study (-5.5+/-1.9), as well as in group B (-3.9+/-2.8 and -4.5+/-2.4, respectively). Baseline 99mTc-Sestamibi uptake was similar in both groups (62.9+/-9.7% vs. 60.3+/-10.4%, p = NS), whereas at dobutamine and postrevascularization studies a significant change (F[2,30] = 65.17, p < 0.0001) and interaction between the two groups (F[2,30] = 33.14, p < 0.0001) were present. Tracer uptake increased significantly in group A both at dobutamine (+ 10.9+/-7.9%, p < 0.001) and at postrevascularization study (12.1+/-8.7%, p < 0.001). Conversely, group B patients showed no change in tracer uptake after dobutamine test (-0.4+/-5.8, p = NS), but only after revascularization (+8.8+/-7.2%, p < 0.001). CONCLUSIONS: The increase in contractility induced by low dose dobutamine infusion in dysfunctional viable myocardium supplied by nearly occluded vessels occurs even in the absence of a significant increase in blood flow. (+info)
Echocardiography-derived left ventricular end-systolic regional wall stress and matrix remodeling after experimental myocardial infarction.
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OBJECTIVES: We tested the hypothesis that regional end-systolic left ventricular (ESLV) wall stress is associated with extracellular matrix remodeling activity after myocardial infarction (MI). BACKGROUND: Increased left ventricular (LV) wall stress is a stimulus for LV enlargement, and echocardiography can be used to estimate regional wall stress. A powerful validation of a noninvasive method of estimating wall stress would be predicting cellular responses after a MI. METHODS: Echocardiographic images were obtained in rats 1, 7, 14 or 21 days after coronary ligation (n = 11) or sham surgery (n = 5). End-systolic left ventricular wall stress was calculated by finite element analysis in three regions (infarcted, noninfarcted and border) from short-axis images. Matrix metalloproteinase-9 (MMP-9) and macrophage density were determined by immunohistochemistry, and positive cells were counted in high power fields (hpf). RESULTS: Average ESLV wall stress was higher in rats with MI when compared to shams irrespective of time point (p < 0.01), and ESLV wall stress in the infarcted regions increased with time (25.1 +/- 5.9 vs. 69.9 +/- 4.4 kdyn/cm2, day 1 vs. 21; p < 0.01). Matrix metalloproteinase-9 expression was higher in infarcted and border regions when compared to noninfarcted regions (22.1 vs. 25.7 vs. 0.10 cells/hpf, respectively; p < 0.01). Over all regions, ESLV wall stress was associated with MMP-9 (r = 0.76; p < 0.001), macrophage density (r = 0.72; p < 0.001) and collagen content (r = 0.67; p < 0.001). End-systolic left ventricular wall stress was significantly higher when MMP-9 positive cell density was greater than 10 cells/hpf (45+/-20 vs. 14+/-10 kdyn/cm2; p < 0.001). CONCLUSIONS: Regional increases in ESLV wall stress determined by echocardiography-based structural analysis are associated with extracellular matrix degradation activity. (+info)
Echocardiographic and morphological correlations in tetralogy of Fallot.
(15/5805)
AIMS: Our aim was to clarify the location and structure of the outlet septum relative to the free-standing subpulmonary infundibulum in the setting of tetralogy of Fallot and to examine its relationship to the other components of the subpulmonary outflow tract, determining their potential influence on clinical outcome. METHODS AND RESULTS: We studied prospectively 41 patients with tetralogy of Fallot (mean age 14 +/- 10.9 months) prior to surgical repair, and compared them with 15 patients undergoing closure of a ventricular septal defect associated with malalignment of the outlet septum but no subpulmonary infundibular stenosis (Eisenmenger ventricular septal defect), and 20 healthy controls. We also examined available autopsied hearts from cases with uncorrected tetralogy of Fallot (8) and Eisenmenger ventricular septal defect (13). Data were indexed for body surface area, and diameter of the tricuspid valve, respectively. The overall length of the subpulmonary infundibulum, including the extent of the muscular outlet septum, was significantly greater for patients with tetralogy of Fallot compared to normals (2.34 +/- 0.6 vs 1.46 +/- 0.34 cm/BSA0.5, P<0.001), whereas the difference between those with tetralogy of Fallot and an Eisenmenger ventricular septal defect was confined to the degree of narrowing of the subpulmonary outlet (0.43 +/- 0.22 vs 2.17 +/- 0.64 cm/BSA0.5, P<0.001). Within the tetralogy of Fallot group, there were linear relationships between deviation of the outlet septum (r= -0.61, P<0.005) and the diameter of the pulmonary valvar orifice (r=0.75, P<0.001), suggesting that growth of the pulmonary arteries may be related to this feature. When patients requiring a transannular patch as part of their surgical repair were compared with those not needing this procedure, differences were found in the diameter of the pulmonary valvar orifice and the pulmonary trunk, but not in the dimensions of the outlet septum. CONCLUSION: The position of the outlet septum in relationship to the remainder of the muscular subpulmonary infundibulum represents a hallmark of tetralogy of Fallot, permitting its differentiation from Eisenmenger ventricular septal defects and normal hearts. (+info)
Lumen reduction measurements of the internal carotid artery before and after Levovist enhancement: reproducibility and agreement with angiography.
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Our aim was to assess reproducibility of three different lumen reduction measuring methods--North American Symptomatic Carotid Endarterectomy Trial, European Carotid Surgery Trial, and common carotid--using power Doppler and color Doppler sonography before and after Levovist enhancement. We included 20 symptomatic patients with mild or severe carotid disease. North American Symptomatic Carotid Endarterectomy Trial, European Carotid Surgery Trial, and common carotid measurements on longitudinal views and European Carotid Surgery Trial measurements on transverse views were performed. Examinations were repeated and the results compared to assess reproducibility of measurements. Correlation with angiography was obtained by calculating Pearson correlation coefficients. Reproducibility was significantly better (P < 0.05) for European Carotid Surgery Trial and common carotid measurements (95% limits of agreement between -10% to 10% and -19% to 17%) as compared to North American Symptomatic Carotid Endarterectomy Trial measurements (95% limits of agreement between -11% to 21% and -21% to 23%). Variability of measurements after enhancement increased slightly (not significant) for both power and color Doppler sonography. Additionally, European Carotid Surgery Trial measurements, using nonenhanced power Doppler or color Doppler sonography, did not correlate significantly with angiography, whereas North American Symptomatic Carotid Endarterectomy Trial and common carotid measurements correlated well with angiography, particularly in power Doppler mode after enhancement (r = 0.88 and r = 0.82, respectively). We conclude that for lumen reduction measurements of the internal carotid artery with power and color Doppler sonography, the common carotid method is the only method that is reproducible and has good correlation with angiography, which slightly improves after Levovist enhancement. (+info)