Stereoselective urinary excretion of bupivacaine and its metabolites during epidural infusion

PURPOSE: Intravascular ultrasound (IVUS) was used to assess in vitro the morphologic and quantitative effects of balloon angioplasty (PTA) of the iliac artery. METHODS: Forty human iliac arteries (>/= 30% area stenosis) were studied with IVUS in vitro before and after PTA and the findings were validated with histology. RESULTS: The sensitivity of IVUS for dissection was 74% and for media rupture 59%. The incidence of vascular damage was higher when the whole segment was analyzed rather than the target site alone. Dissections occurred at the thinnest region of the plaque, unrelated to plaque calcification. Following PTA, quantitative changes at the target site were greater compared with the overall data derived from all cross-sections. The increase in lumen area was caused solely by an increase in vessel area. CONCLUSIONS: IVUS is sensitive in detecting dissections, which occurred irrespective of calcification at the thinnest region of the plaque. The increase in lumen area after PTA was caused by stretching of the vessel.     

Atherosclerotic plaque components in human aortas contrasted by ex vivo imaging using fast spin-echo magnetic resonance imaging and spiral computed tomography

RATIONALE AND OBJECTIVES: Imaging techniques that distinguish atherosclerotic plaque components may be useful in identifying the nature of the atherosclerotic lesion and determining the best method of treatment for obstructive vascular mining the best method of treatment for obstructive vascular disease. This study compares fast spin-echo (FSE) magnetic resonance (MR) and spiral computed tomography (CT) images of excised human atherosclerotic aortas to determine which imaging technique provides the best contrast between plaque components ex vivo. METHODS: Aortas were imaged using four FSE sequences in MR with and without frequency-selective fat saturation, and using spiral CT without contrast. The average signal intensity of a region of calcification, thrombosis, fatty plaque, and normal vessel wall was measured on all images and compared. RESULTS: The use of fat saturation pulses in MR did not significantly alter the signal from atherosclerotic plaque for the sequences used. Proton density-weighted FSE sequences that collected early echoes were better than other FSE sequences and CT at differentiating calcification from all soft tissues. T2-weighted FSE sequences that collected later echoes were best at soft-tissue discrimination. CONCLUSIONS: The FSE techniques used were superior to nonenhanced spiral CT in discriminating plaque components ex vivo, including calcification.     

Usefulness of magnetic resonance imaging of cardiac and paracardiac masses

In this study, magnetic resonance imaging was compared with histology to evaluate the usefulness of magnetic resonance imaging to distinguish malignant from benign cardiac and paracardiac masses in 55 patients. Tumor location, tissue composition, and pericardial or pleural effusion all were identified as key predictors of lesion type. Observers were accurate in the prediction of lesion type (area under curve 0.88 and 0.92), and there was good interobserver variability (Cohen's kappa = 0.64).     

The value of the CT scanner in intensive care

The composition of atherosclerotic plaques in the carotid artery is assumed to be related to the development of neurological symptoms. The echo patterns produced by B-mode ultrasound may be of use in the assessment of the plaques' composition. It is suggested that fibrotic and "stable" plaques are more echogenic than lipid/hemorrhagic and echolucent or "unstable" plaques. B-mode ultrasound procedures were performed 1 day prior to surgery on 46 consecutive endarterectomies. Two observers assessed the plaques according to their echo pattern and echogenicity and sorted them into three categories: 1) predominantly echolucent, 2) heterogeneous, and 3) predominantly echogenic. The intraobserver agreement was moderate (kappa = 0.44) and the interobserver agreement low (kappa = 0.38). Furthermore, subjective categorization of plaque types resulted in type 1 plaques being as fibrotic as type 2 or 3 plaques. We conclude that B-mode ultrasound and subsequent subjective categorization of atherosclerotic plaques cannot adequately determine the volume of fibrosis or lipids within the plaque.     

Determination of arterial diameters, length and mass of the plaque, and theoretical volume in the internal carotid artery by quantitative vascular echography

To study the evolution of atherosclerosis, the consensual changes that occur in the arterial wall, lumen, and atheroma must be evaluated. The authors propose a new, noninvasive method of obtaining arterial diameters, length and mass of plaque, and theoretical volume in the internal carotid artery. The study was performed in 37 patients with different degrees of atherosclerosis (from 20% to 50%). All patients underwent echo examination. Long-axis tomographic planes were recorded with the same angle of incidence by placing a goniometer around the neck. Furthermore, the arterial diameters and the plaque length were measured from photorecordings, and theoretical arterial volume (sum of two bitruncated semiellipsoids), residual volume (Simpson's integral rule), and plaque mass (difference between theoretical vascular volume and residual volume) were calculated. Intraobserver and interobserver variability and reproducibility were tested in all the measurements and calculations. Intraobserver/interobserver variability and reproducibility were found to be less than 8% according to all measurements and calculations. These results indicate that the method is reproducible and allows noninvasive, quantitative assessments of vascular geometry in evolving atherosclerosis.     

Paradoxic decreases in atherosclerotic plaque mass in insulin-treated diabetic patients

This study assessed the impact of diabetes mellitus on atherosclerotic lesion formation. Seventy insulin-treated diabetics, 150 non-insulin-treated diabetics, and 607 nondiabetics with chronic anginal syndromes and de novo native coronary stenoses were studied using (1) angiography, and (2) intravascular ultrasound (reference and lesion arterial, lumen, and plaque areas; area stenosis [reference-lesion/reference lumen area]; remodeling index [reference-lesion lumen area/lesion-reference plaque area]; and slope of the regression line relating lumen area to plaque burden [plaque/arterial area]). Despite being diabetic for longer and having similar lumen compromise, insulin-treated patients had (1) less reference plaque (8.3 +/- 3.4 vs 10.5 +/- 4.5 mm2, p = 0.0015), (2) less stenosis plaque (13.0 +/- 4.9 vs 16.9 mm2, p <0.0001), (3) smaller reference arterial areas (17.1 +/- 5.4 vs 19.7 +/- 6.2 mm2, p = 0.0063), and (4) smaller stenosis arterial areas (15.3 +/- 4.9 vs 19.5 +/- 6.5 mm2, p <0.0001) than non-insulin-treated diabetics. With use of multivariate linear regression analysis, insulin use was an independent (and negative) predictor of reference plaque and arterial areas (p = 0.0308 and p = 0.0179) and stenosis plaque and arterial areas (p = 0.0117 and p = 0.0066). This was also true when normalized for body surface area. The remodeling index showed that insulin treatment resulted in an exaggerated impact of plaque accumulation on lumen compromise. This was confirmed by the slope of the regression line relating lumen area to plaque burden. Patients with a longer duration of diabetes who were treated with insulin for > or = 1 year had (paradoxically) less reference segment and stenosis plaque accumulation. Possible explanations include impaired adaptive remodeling and/or arterial (and plaque) shrinkage.     

Serial volumetric (three-dimensional) intravascular ultrasound analysis of restenosis after directional coronary atherectomy

OBJECTIVES: We report the use of three-dimensional (volumetric) intravascular ultrasound (IVUS) analysis to assess serial changes after directional coronary atherectomy (DCA). BACKGROUND: Recent serial planar IVUS studies have described a decrease in external elastic membrane (EEM) area following catheter-based intervention as an important mechanism of late lumen renarrowing. METHODS: Thirty-one patients with de novo native coronary lesions treated with DCA in the Serial Ultrasound Restenosis (SURE) Trial and in Optimal Atherectomy Restenosis Study (OARS) were enrolled in this study. Serial IVUS was performed before and after intervention and at 6 months' follow-up. In a subgroup of 18 patients from the SURE trial, IVUS was also performed at 24 h and at 1 month postintervention. Segments, 20-mm-long (200 image slices), were analyzed using a previously validated three-dimensional, computerized, automated edge-detection algorithm. The EEM, lumen, and plaque+media (P+M = EEM-lumen) volumes were calculated. RESULTS: At follow-up, lumen volume was smaller than at postintervention (159+/-69 mm3 vs. 179+/-49 mm3, p = 0.0003). From postintervention to follow-up, there was a decrease in EEM volume (377+/-107 to 352+/-125 mm3, p < 0.0001), but no change in P+M volume (p = 0.52). The delta lumen volume correlated strongly with deltaEEM volume (r = 0.842, p < 0.0001), but not with deltaP+M volume. In the 18 patients from the SURE Trial, the decrease in lumen and EEM volumes occurred late, between 1 month and 6 months of follow-up. CONCLUSIONS: Volumetric IVUS analysis demonstrated that late lumen volume loss following DCA was a result of a decrease in EEM volume. This was a late event, occurring between 1 and 6 months' postintervention.     

Highly localized arterial remodeling in patients with coronary atherosclerosis: an intravascular ultrasound study

BACKGROUND: Preservation of luminal area and symmetry in the presence of irregular plaques necessitates local expansion of the artery wall. METHODS AND RESULTS: Cross-sectional dimensions of coronary arteries in 65 patients were measured with the use of intravascular ultrasound. A total of 104 arterial segments were studied, of which 88 had atherosclerosis; 16 served as nonatherosclerotic control segments. Three features of atherosclerotic arterial segments were classified: (1) plaque formation, (2) lumen shape, and (3) shape of arterial external elastic lamina. With our intravascular ultrasound-based three-level classification system, we identified three patterns that accounted for 89% of all atherosclerotic arterial segments: (1) concentric plaque with a circular lumen and a circular external elastic lamina (n= 17), (2) eccentric plaque with a circular lumen and an oval external elastic lamina (n=35), and (3) eccentric plaque with an oval lumen and a circular external elastic lamina (n=26). A circular lumen was preserved in 66% of all atherosclerotic arterial segments. Arterial segments with a circular lumen in the presence of an eccentric plaque had a significantly larger lumen area than the other two main groups (P<.05). CONCLUSIONS: With our intravascular ultrasound-based classification, we provided information regarding the local remodeling response in the coronary artery wall. In a majority of cases, a circular lumen is maintained. Failure of this highly localized response to be operative may contribute to the development of stenotic lesions at a specific site in the artery.     

Intravascular ultrasound--the new gold standard?

Intravascular ultrasound (IVUS) has evolved to a research tool to an intrinsic part of modern invasive cardiology. The main reason is the capability to obtain "in-vivo" micro anatomy by means of miniaturized echo-transducers with an outer diameter of 2.9-3.5 French. For the first time it is possible to base decisions not only on lumenograms but also on vessel wall assessment. The capabilities of IVUS can be divided in its diagnostic and intervention associated potentials. The diagnostic strength of IVUS is the ability to monitor compensatory coronary artery enlargement as a response to arteriosclerosis, to assess intermediate lesions, to reveal occult left main stem disease, and angiographically "silent" arteriosclerosis. In conjunction with the estimation of intracoronary flow reserve, patients with the diagnosis of coronary "syndrome X" can be better classified into those with or without early signs of arteriosclerosis. Additionally, IVUS is at present the only method allowing the classification of coronary artery lesions according to the AHA/ACC Stary classification. The intervention associated potentials of IVUS are the ability to allow optimal device selection, i.e. rotablators in calcified lesions or atherectomy devices in large plaque burden. The effects of PTCA on vessel wall morphology can be studied in great detail and the effect on luminal gain can be assessed almost on-line. The correlation between IVUS and angiography for estimation of luminal dimensions is inferior, because angiography is not able to describe complex luminal geometries. Several groups showed that the residual plaque area even after angiographically successful PTCA lies still in the range of 60%. A significant reduction of this number may influence long-term outcome after PTCA. Minimal luminal areas and residual plaque area after PTCA seem to be an indicator of restenosis, while the presence or absence of dissections seem to be less predictive. Additionally, the main mechanism of restenosis after PTCA is vessel shrinkage, not intimal hyperplasia. Intravascular monitoring of stent expansion led to high-pressure stent deployment with significant increase in post-procedural luminal diameters and finally the ability to withhold anticoagulation in patients with optimal stent deployment and to lower subacute stent thrombosis rates. First results for IVUS guided PTCA show a superior gain in post procedural free lumen without an increased complication rate. In the future, integrated devices, like balloons on IVUS catheters, steerable catheters, integrated flow and pressure transducers, tissue characterisation, and 0.018 inch IVUS guidewires will further enhance the usefulness of IVUS.     

Differential expression patterns of GABA transporters (GAT1-3) in the rat olfactory bulb

OBJECTIVES: This report used intravascular ultrasound and quantitative coronary angiography to explore the relation between lesion-associated calcium and risk factors, clinical presentation and angiographic severity of coronary artery stenoses. BACKGROUND: Coronary artery calcium is a marker for significant coronary atherosclerosis. Noninvasive procedures are being proposed as screening tests for coronary artery disease. Intravascular ultrasound identification of tissue calcium has been validated in vitro. METHODS: Independent chart review, preintervention intravascular ultrasound imaging and coronary angiography were used to study primary native vessel lesions in 1,442 patients. Target lesions and reference segments were evaluated according to previously published quantitative and qualitative methods. Results are presented as mean value +/- SD. RESULTS: Overall, 1,043 lesions contained target lesion calcium (72%); the arc of target lesion calcium was 110 +/- 109 degrees. Lesions with an ultrasound plaque burden > 0.75 or an angiographic diameter stenosis > 0.25 had a prevalence of calcium of at least 65%, with a mean arc > 100 degrees. Intermediate lesions had as much target lesion calcium as did angiographically severe lesions. Using multivariate linear regression analysis, patient age, stable (vs. unstable) angina and the intravascular ultrasound lesion site and reference segment plaque burden (but not the angiographic diameter stenosis) were the independent predictors of the arc of target lesion calcium (all p < 0.0001). CONCLUSIONS: Intravascular ultrasound analysis shows that coronary calcification correlates with plaque burden but not with degree of lumen compromise. Thus, the noninvasive detection of coronary calcium is predictive of future cardiac events, presumably because coronary calcification is a marker for overall atherosclerotic plaque burden. Coronary calcium increases with increasing patient age and is less common in unstable lesion subsets.     

Merger management: a challenge to nursing leadership

Intravascular ultrasound (IVUS) represents a new method to assess vessel lumen and wall morphology. To prospectively evaluate the usefulness of IVUS for further therapeutic decisions in left main stem (LM) lesions with unclear angiographic definition, this study was launched. We studied 56 patients with significant stenosis of the LAD and/or LCX arteries and questionable LM morphology. 30-MHz IVUS catheters with 2.9 or 3.2 F outer diameters were used. A significant luminal reduction of the left main stem was defined as an area stenosis greater than 50% or a minimal luminal diameter smaller than 3 mm as determined by IVUS. 36 of 56 patients (61%) fulfilled these criteria. Additionally, 12 patients showed a ruptured plaque within the LM. 30 of these 36 patients were originally thought to be candidates for angioplasty. After positive IVUS 34 of these 36 patients were sent to surgery. No perioperative ischemic complications occurred. In angiographically unclear left main stem findings. IVUS establishes a definitive diagnosis. After IVUS confirmation of significant left main stem pathology operative management should be the preferred approach as compared to transluminal coronary interventions. However, prospective randomized studies are needed to define the most efficient approach.     

Effect of pramipexole in treatment of resistant restless legs syndrome

When atherosclerotic plaques develop, the cross-sectional area of the artery at that point often increases to accommodate the plaque without any reduction in lumen size. In consequence the angiogram does not detect a high proportion of atherosclerotic plaques. The increase in size of the artery (compensatory dilatation-arterial remodelling) varies widely in degree between different plaques even in the same artery. Dilatation of a degree to prevent any loss of lumen size is regarded as adequate compensatory dilatation. In contrast, other plaques are associated with no or minimal increase in the vessel cross-sectional area and a reduction in lumen size in present (inadequate compensation). High-grade stenosis is in particular associated with a total failure of remodelling. Such plaques may have had a rapid growth phase, out-pacing the ability of the medial smooth muscle cells to undergo a rearrangement. The phenomenon of remodelling has important consequences for pathologists who use the traditional method of comparing the lumen size relative to the cross-sectional area of the vessel at the site of a plaque to measure stenosis. The area of the vessel at this point may be anything up to 60% above its size before the plaque developed. An error is introduced which on average overestimates diameter stenosis by 30% when compared to an angiographic equivalent method in which the lumen size at the lesion is compared to the lumen size at an adjacent segment of artery without a plaque.     

Preliminary experience with adjunct directional coronary atherectomy after high-speed rotational atherectomy in the treatment of calcific coronary artery disease

A high-speed rotational atherectomy was performed followed by adjunct directional atherectomy in 10 patients with symptomatic coronary artery disease and calcified target lesions and the results were evaluated using quantitative coronary arteriography and intravascular ultrasound. Target lesion calcium is common in obstructive coronary artery disease. High-speed rotational coronary atherectomy preferentially abrades noncompliant atherosclerotic plaque material, especially calcium, but often requires adjunct balloon angioplasty to achieve optimal lumen dimensions. Directional coronary atherectomy has limited efficacy in heavily calcified plaque; usually, it is a definitive primary procedure in large arteries with noncalcified target lesions. Neither of these devices alone is effective in treating calcified target lesions in large coronary arteries. Before intervention, after rotational and adjunct directional atherectomy, these measurements were obtained: quantitative coronary arteriographic measurements of minimal lumen diameter and percent diameter stenosis and intravascular ultrasound measurements of external elastic membrane, lumen, and plaque+media cross-sectional areas; percent cross-sectional narrowing; minimal lumen diameter; and target-lesion arc of calcium. With use of quantitative coronary arteriography, the preintervention minimal lumen diameter measured 0.7 +/- 0.4 mm, increased to 1.5 +/- 0.5 mm after rotational atherectomy (p = 0.0013) and to 2.5 +/- 0.3 mm after adjunct directional atherectomy (p < 0.001). The preintervention percent diameter stenosis measured 78 +/- 15%, decreased to 50 +/- 17% after rotational atherectomy (p = 0.0011), and to 17 +/- 11% (p < 0.001) after adjunct directional coronary atherectomy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Computation of a location shift between two subsequent intra vascular ultrasound registrations by cross-correlation analysis of the lumen area functions

For longitudinal studies on atherosclerosis and restenosis after angioplasty by intravascular ultrasound (IVUS), it is essential that repeated studies are performed at exactly the same location along an arterial section. In human femoral arteries, lumen and plaque area functions of two subsequent IVUS pullback maneuvers were compared by cross-correlation analysis. In cross-correlation analysis of two functions with equal abscissa values, the data sets are repetitively correlated after incremental shifts of the two functions along the abscissa. This results in multiple correlation coefficients with a maximum at the relative position where the two functions show the closest match. In group A (12 patients), both pullbacks were performed after angioplasty and in group B (17 patients) one pullback was performed before angioplasty and the second immediately after angioplasty. In group A, cross-correlation showed a shift between lumen area functions of 5 mm in one patient and no shift in the other patients. Maximum correlation coefficients in group A ranged from 0.644 to 0.978. Four patients from group B showed shifts from 2.5 to 35 mm. Maximum coefficients were significantly smaller than in group A: 0.259-0.864 (p < 0.01). Plaque area functions in group B showed higher correlations (0.468-0.862, p = 0.034) and only two shifts. Cross-correlation of lumen and plaque area functions may be used to compute location shifts between two subsequent IVUS registrations and to correct such shifts.     

Intravascular ultrasound in determining the end point of percutaneous transluminal coronary angioplasty

Intravascular ultrasound (IVUS) imaging was used to measure internal luminal area immediately after percutaneous transluminal coronary angioplasty (PTCA) in 83 patients (59 males, 24 females, mean age 63 +/- 12 years) with angina pectoris to determine the need for additional intervention. The effectiveness of these interventions to prevent restenosis was also studied. Thirty-five patients (42%) with insufficient dilatation revealed an internal luminal area less than 5 mm2 or luminal stenosis greater than 60% as evaluated by IVUS imaging following the procedure. The luminal area increased from 4.5 +/- 1.1 to 7.9 +/- 2.8 mm2 and the percentage luminal stenosis improved from 66 +/- 9% to 54 +/- 9% in patients who underwent further dilatation with a larger size balloon, longer dilatation time, directional coronary atherectomy, or stenting. The insufficient dilatation group exhibited hard plaque and calcification more frequently than in the other group (48 patients, 58%) in whom sufficient dilatation of the target lesion was achieved. The incidence of restenosis in the sufficient dilatation group was 25%, compared to 33% of the patients receiving additional treatment after IVUS imaging and 42% in the 192 patients who underwent PTCA without IVUS imaging. IVUS imaging is a useful method for evaluation of complex luminal morphology to decrease the incidence of restenosis and for determination of the end point and the extent of dilatation required.     

Treatment success with a mandibular advancement device is related to supine-dependent sleep apnea

OBJECTIVES: This study was performed to determine predictors of in-stent restenosis from a high volume, single-center practice. BACKGROUND: Intracoronary stents have been shown to reduce the restenosis rate as compared with balloon angioplasty, but in-stent restenosis continues to be an important clinical problem. METHODS: Between April 1993 and March 1997, 1,706 patients with 2,343 lesions were treated with a variety of intracoronary stents. The majority of stents were placed with high pressure balloon inflations and intravascular ultrasound (IVUS) guidance. Angiographic follow-up was obtained in 1,173 patients with 1,633 lesions (70%). Clinical, angiographic and IVUS variables were prospectively recorded and analyzed by univariate and multivariate models for the ability to predict the occurrence of in-stent restenosis defined as a diameter stenosis > or =50%. RESULTS: In-stent restenosis was angiographically documented in 282 patients with 409 lesions (25%). The restenosis group had a significantly longer total stent length, smaller reference lumen diameter, smaller final minimal lumen diameter (MLD) by angiography and smaller stent lumen cross-sectional area (CSA) by IVUS. In lesions where IVUS guidance was used, the restenosis rate was 24% as compared with 29% if IVUS was not used (p < 0.05). By multivariate logistic regression analysis, longer total stent length, smaller reference lumen diameter and smaller final MLD were strong predictors of in-stent restenosis. In lesions with IVUS guidance, IVUS stent lumen CSA was a better independent predictor than the angiographic measurements. CONCLUSIONS: Achieving an optimal stent lumen CSA by using IVUS guidance during the procedure and minimizing the total stent length may reduce in-stent restenosis.     

Clostridium septicum infection and hemolytic uremic syndrome

Ultrasonography of the hip was performed sequentially by two different examiners in 75 infants. The ultrasound strips were reviewed twice by three paediatric orthopaedic surgeons and classified by the Graf method. The intraobserver and interobserver agreement between the interpretations was analysed using simple and weighted kappa coefficients calculated for agreement on the Graf classification and for grouping as normal (types 1A to 2A), and abnormal requiring treatment (types 2B to 4). When examining the same ultrasound strip, intraobserver agreement for the Graf classification was substantial (mean kappa 0.61), but interobserver agreement was only moderate (kappa 0.50). For the grouping into normal and abnormal, the mean kappa value for intraobserver agreement was 0.67 and for interobserver agreement 0.57. Because of the significant differences in agreement between normal and abnormal hips, we analysed a subgroup of those with at least one abnormal interpretation. Intraobserver agreement within this subgroup showed moderate reliability (kappa 0.41), but interobserver agreement was only fair (kappa 0.28). Interpretations of two different strips performed sequentially showed significantly lower agreement with an intraobserver kappa value of 0.29 and an interobserver value of 0.28. In the subgroup with at least one abnormal reading, the intraobserver kappa was 0.09 and the interobserver 0.1. Our findings suggest that both the technique of performing ultrasonography and the interpretation of the image may influence the result.     

Validation of the in vivo intravascular ultrasound measurement of in-stent neointimal hyperplasia volumes

OBJECTIVES: This study was undertaken to validate the in vivo intravascular ultrasound (IVUS) measurement of in-stent neointimal hyperplasia (IH) volumes. BACKGROUND: Because stents reduce restenosis compared to balloon angioplasty, stent use has increased significantly. As a result, in-stent restenosis is now an important clinical problem. Serial IVUS studies have shown that in-stent restenosis is secondary to intimal hyperplasia. To evaluate strategies to reduce in-stent restenosis, accurate measurement of in-stent neointimal tissue is important. METHODS: Using a porcine coronary artery model of in-stent restenosis, single Palmaz-Schatz stents were implanted into 16 animals with a stent:artery ratio of 1.3:1. Intravascular ultrasound imaging was performed at 1 month, immediately prior to animal sacrifice. In vivo IVUS and ex vivo histomorphometric measurements included stent, lumen and IH areas; IH volumes were calculated with Simpson's rule. RESULTS: Intravascular ultrasound measurements of IH (30.4+/-11.0 mm3) volumes correlated strongly with histomorphometric measurements (26.7+/-8.5 mm3, r=0.965, p < 0.0001). The difference between the IVUS and the histomorphometric measurements of IVUS volume was 4.1+/-2.7 mm3 or 15.8+/-11% (standard error of the estimate=0.7). Both histomorphometry and IVUS showed that IH was concentric and uniformly distributed over the length of the stent. Intravascular ultrasound detected neointimal thickening of < or =0.2 mm in 5 of 16 stents. Sample size calculations based on the IVUS measurement of IH volumes showed that 12 stented lesions/arm would be required to show a 50% reduction in IVUS-measured IH volume and 44 stented lesions/arm would be required to show a 25% reduction in IH volume. CONCLUSION: In vivo IVUS measurement of IH volumes correlated strongly with ex vivo histomorphometry. Using volumetric IVUS end points, small sample sizes should be necessary to demonstrate effectiveness of strategies to reduce in-stent restenosis.     

Interobserver variability in the diagnosis of high-grade prostatic intraepithelial neoplasia and adenocarcinoma

High-grade prostatic intraepithelial neoplasia (PIN) is a strong predictor of carcinoma when identified in small-needle biopsy specimens. However, the diagnostic variability of PIN is unknown. Eight pathologists reviewed 321 prostatic biopsy specimens to assess the variability of the diagnosis of high-grade PIN and carcinoma. All of the specimens were classified as negative, high-grade PIN, suspicious for high-grade PIN, carcinoma, or suspicious for carcinoma, more than one diagnosis was permitted, except for negative. We compared diagnoses made by two observers by pairing them for negative versus high-grade PIN, negative versus carcinoma, high-grade PIN versus carcinoma, and all diagnostic categories together. Mean kappa coefficient values for 28 interobserver combinations were 0.451, 0.845, 0.669, and 0.482, respectively, for each of the four comparison combinations considered. Our results indicate a high level of agreement, "almost perfect" (kappa = 0.81-1.0) for carcinoma, "moderate" (kappa = 0.41-0.60) for high-grade PIN, and "substantial" (kappa = 0.61-0.81) for high-grade PIN versus carcinoma. We found that variability was related to the level of interest in prostatic pathology, the conditions of the study, the subjective application of diagnostic criteria, and the influence of peers and clinical colleagues.