Combination of a clinical risk assessment score and rapid whole blood D-dimer testing in the diagnosis of deep vein thrombosis in symptomatic patients.
(73/1865)
PURPOSE: The clinical diagnosis of deep vein thrombosis (DVT) is unreliable in more than 50% of cases, and, in recent years, plasma D-dimer assays have been used to predict the presence of DVT with high sensitivity and negative predictive values. This study investigated the use of a rapid whole blood test that could be performed and interpreted by the bedside in addition to a clinically derived risk assessment score (RAS) to determine whether a practical and cost-effective clinical model could be developed for the diagnosis and exclusion of DVT in symptomatic patients. METHODS: Two hundred consecutive patients who were referred to the vascular laboratory with clinically suspected DVT underwent the following procedures: (1) clinical assessment and stratification into low, moderate, or high risk for DVT on the basis of an RAS related to history, symptoms, and physical examination findings; (2) rapid (5-minute) whole blood D-dimer testing with a semi-qualitative agglutination technique on a fingerprick blood sample; and (3) color flow duplex ultrasound scanning with standard criteria for the diagnosis of proximal and calf DVT. RESULTS: Forty-six patients (23%) had acute DVT on duplex ultrasound scanning. Of these cases, 28 (61%) had proximal DVT and 18 (39%) were confined to the calf. A total of 88 patients were classified as low risk, 67 were classified as moderate, and 45 were classified as high risk on the basis of the RAS method. Of the patients who were classified at low risk, 4.5% (4/88) had DVT, as compared with 17.9% (12/67) in the moderate clinical risk group and 66.7% (30/45) in the high risk group. Isolated calf DVT was found in 30% (9/30), 50% (6/12), and 75% (3/4) of the high, moderate, and low risk groups, respectively. The sensitivity (8.7%, 26.1%, 65.2%), specificity (45.5%, 64.3%, 90.3%), positive predictive value (4.5%, 17.9%, 66.7%), and overall accuracy rate (37%, 55.5%, 84.5%) of the low, moderate, and high risk groups, respectively, in the diagnosis of DVT increased significantly with increasing risk score stratification. The sensitivity, specificity, positive and negative predictive value, and overall accuracy of the rapid D-dimer test for all DVT were 91.3%, 81.9%, 60%, 96.9%, and 84%, respectively, with a 100% sensitivity and negative predictive value for proximal DVT. A combination of the RAS and D-dimer identified a low risk group with a negative D-dimer as having less than a 1% likelihood of DVT and a high risk group with positive D-dimer as having a likelihood of more than 90%. CONCLUSION: A combination of clinical assessment and rapid D-dimer testing provides an effective means of excluding proximal DVT in symptomatic patients. The application of a clinical diagnostic model on the basis of these parameters has the potential for saving a large proportion of unnecessary duplex scans with the associated time and costs. (+info)
The effect of graded compression elastic stockings on the lower leg venous system during daily activity.
(74/1865)
PURPOSE: We evaluated the effects of wearing 20 to 30 mm Hg gradient thigh-length stockings during daily activity on the lower leg venous system. METHODS: Twenty-one healthy women volunteers, aged 39 +/- 12 years, were examined. One subject was clinical class 4, one was class 2, two were class 1, and the remainder were class 0. The diameter of the posterior tibial, peroneal, and greater saphenous veins were measured at midcalf by means of bilateral duplex ultrasound scanning; calf circumference was measured at the same level. In addition, the number and caliber of all detectable medial calf perforating veins were recorded. Each subject was examined on two separate days, one while wearing the gradient stockings and one not wearing them. Baseline measurements were made on each day before the subjects began their workday, with follow-up measurements made after approximately 4.5 hours of normal activity. RESULTS: Calf circumference increased an average of 23.8 +/- 10.1 mm without stockings (P <.001) and decreased by 5.2 +/- 7.0 mm when wearing stockings (P =.003). The number of detected perforating veins increased without stockings by 1.8 +/- 2.0 at the follow-up examination (P =.002); with stockings, the change was 0.4 +/- 1.2 (P = NS). CONCLUSION: Graded compression elastic stockings help preserve lower leg venous caliber and tone throughout the deep, superficial, and perforating venous systems during normal ambulatory activity, and this may, in part, explain their beneficial effects. (+info)
The effect of pregnancy on the lower-limb venous system of women with varicose veins.
(75/1865)
OBJECTIVES: to assess the effect of pregnancy on the lower-limb venous system of women with varicose veins. Design a longitudinal prospective study of 11 pregnant women, with varicose vein disease. METHODS: eleven pregnant women with varicose veins were recruited as part of a larger study. Veins were assessed in both lower limbs using colour-flow duplex scanning at a 75 degrees head-up tilt. The diameter and velocity and duration of reflux were measured in each vein at 12, 20, 26, 34, 38 weeks gestation and 6 weeks postpartum. RESULTS: eleven women had reflux and varicose veins demonstrated at first scan. All veins dilated with increasing gestation. This was maximal in the superficial system, reaching significance (p+info)
Fat- and bone marrow-impregnated small diameter PTFE grafts.
(76/1865)
OBJECTIVES: to evaluate an alternative and simple technique which consists in impregnation of a synthetic prosthesis with either autogenic omental fat or bone marrow. These tissues have been selected based on previous works and because they contain multiple cellular and extracellular compounds with biological healing properties (i.e. angiogenesis, endothelialisation, etc.). DESIGN: PTFE grafts of Group 1 were impregnated with fatty tissue, those of Group 2 with bone marrow and those of Group 3 served as controls. MATERIALS: nine mongrel dogs divided among these three groups. PTFE grafts are 3 mm in diameter. METHODS: in each animal, both iliac arteries were submitted to an end-to-side ilio-iliac bypass. At 3 months, pathology assessment was performed. RESULTS: group 1: all grafts were thrombosed and intimal hyperplasia was found occluding the anastomotic sites. Group 2: 4/6 grafts were patent and their mid-portion presented a thin neointima which did not totally cover the anastomotic sites. Group 3: 2/5 grafts were patent and their mid-portion as well as the anastomotic sites were covered with neointima which was hyperplastic in some areas. CONCLUSIONS: addition of bone marrow cells may contribute to improve the quality of the healing process. (+info)
Grading internal carotid artery stenosis using B-mode ultrasound (in vivo study)
(77/1865)
OBJECTIVE: to determine the value of percentage area and diameter reduction in grading ICA stenosis using colour-coded B-mode transverse ultrasonic images. MATERIALS AND METHODS: measurement of the percentage area and diameter reduction of the common carotid, external carotid and internal carotid (at the point of maximum stenosis) were performed, using duplex scanning with colour-flow imaging preoperatively, in 33 patients (six patients were excluded). The duplex measurements were compared to the percentage area and diameter reduction from transverse section of the specimens. Peak systolic (PSV) and end-diastolic velocities (EDV) were measured at the proximal CCA and ICA within the jet of turbulence. A mm scale was placed next to the specimen block, which was captured by video. The area reduction was measured by playing the video and using the same duplex software. RESULTS: linear-regression analysis of the percentage area reduction of the in vivo against the specimen measurements showed a good linear relationship (r=0.9047). The in vivo duplex measurements had 95% confidence interval (CI) of 8% (95% CI of diameter reduction 5%). CONCLUSION: using the gold standard of fixed histological endarterectomy specimen, the results indicate that transverse image obtained with colour B-mode imaging is more appropriate in determining the degree of stenosis. (+info)
Eversion endarterectomy versus open thromboendarterectomy and patch plasty for the treatment of internal carotid artery stenosis.
(78/1865)
OBJECTIVE: in 1996 we changed our treatment for stenosis of the internal carotid artery (ICA) from open thromboendarterectomy and PTFE-patch plasty (TEA) to eversion endarterectomy (EEA). DESIGN: retrospective study. METHODS: a total of 475 EEAs of the ICA were performed between 2/96 and 11/96. These results were compared to the results of TEA carried out between 2/94 and 11/94 (n=388). RESULTS: clamping and operation time were significantly shorter for EEA. Neurological complications included transient ischaemic attacks in 1. 0% in the EEA group versus 1.3% after TEA (p=0.72), minor strokes (0. 6% vs. 1.8%, p=0.10) and major strokes in 1.5% versus 1.1% (p=0.59). The rate of restenosis >50% was 2.5% after EEA and 10.2% after TEA. The only detectable difference of statistical significance in complication rates was in the lesions of the hypoglossal nerve (5.3% vs. 2.6%, p=0.04). CONCLUSIONS: EEA of the ICA is a safe procedure for carotid reconstruction with the additional advantages of short clamping time, possibility of simultaneous shortening of an elongated ICA, and no requirement for patching. (+info)
Fetal cardiac development and hemodynamics in the first trimester.
(79/1865)
OBJECTIVE: To describe fetal cardiac and hemodynamic development in the first trimester of pregnancy. SUBJECTS AND METHODS: Forty-eight pregnancies were prospectively studied with transvaginal ultrasound and color Doppler. Fetal heart rate and size were documented together with the presence of inflow and outflow wave-forms and valve signals. RESULTS: Heart rate and size showed a positive correlation with gestational age. At 6 weeks of gestation, 20% of the cardiac cycle was occupied by the isovolumic contraction time (ICT); the isovolumic relaxation time (IRT) occupied 16% and remained unchanged, while the ICT progressively shortened and was not measurable after 12 weeks. The peak inflow velocities had changed from monophasic to biphasic by 10 weeks of gestation. At 7 weeks of gestation, semilunar valves were detected in 10% of examinations and the atrioventricular valves in 3%. The detection rate for both valves at 12 weeks was > or = 90%. In pregnancies that miscarried, the detection rate for both was < 25%. CONCLUSIONS: The Doppler signals that characterize the heart during the first trimester suggest effective heart compliance by 12 weeks. Normal valve development can be inferred from non-invasive Doppler recordings. (+info)
Yolk sac and umbilicoplacental hemodynamics during early human embryonic development.
(80/1865)
OBJECTIVES: To determine the relationship between the yolk sac and umbilicoplacental circulations during the first trimester of pregnancy. DESIGN: Sixteen normal singleton pregnancies were included in this longitudinal study. Transvaginal ultrasonography with color and pulsed Doppler was performed at 5+, 7+, 8+ and 10+ gestational weeks. Fetal heart rate and blood velocity waveforms of yolk sac, umbilical and chorionic arteries were obtained. RESULTS: The detection rate of arterial blood flow in the yolk sac increased significantly from 5+ (2/16) to 7+ gestational weeks (12/16). Thereafter, it declined significantly and no arterial blood flow was detected at 10+ weeks. When the arterial blood flow was observable in the yolk sac, all waveforms consisted of continuous diastolic blood flow. There were no significant changes in peak systolic velocity (PSV), time-averaged maximum velocity (TAMXV), pulsatility index (PI) or resistance index (RI) values of the yolk sac arteries during the study period. In umbilical arteries, blood flow was detected in two of 16 patients at 5+ weeks and in all cases thereafter. The mean umbilical artery PSV (SD) increased from 7.2 cm/s (3.7) at 8+ weeks to 13.0 cm/s (2.9) at 10+ weeks (p = 0.001). No changes in PI values were found and the absence of diastolic flow was typical of the umbilical artery during the study period. In chorionic arteries, blood flow was detected in six out of 16 subjects at the 5+ week, in 14 out of 16 patients at the 7+ week and in every case thereafter. No changes in PSV or TAMXV values were found. CONCLUSIONS: Our results showed that the arterial signals in the yolk sac circulation disappeared and the umbilicoplacental circulation increased between 8+ and 10+ weeks of gestation. This indicates that the placenta replaces the yolk sac as an essential source of blood supply to the embryo at that time. (+info)