Catheter-directed thrombolysis vs. anticoagulant therapy alone in deep vein thrombosis: results of an open randomized, controlled trial reporting on short-term patency.

BACKGROUND: Approximately one in four patients with acute proximal deep vein thrombosis (DVT) given anticoagulation and compression therapy develop post-thrombotic syndrome (PTS). Accelerated removal of thrombus by thrombolytic agents may increase patency and prevent PTS. OBJECTIVES: To assess short-term efficacy of additional catheter-directed thrombolysis (CDT) compared with standard treatment alone. PATIENTS AND METHODS: Open, multicenter, randomized, controlled trial. Patients (18-75 years) with iliofemoral DVT and symptoms < 21 days were randomized to receive additional CDT or standard treatment alone. After 6 months, iliofemoral patency was investigated using duplex ultrasound and air-plethysmography assessed by an investigator blinded to previous treatment. RESULTS: One hundred and three patients (64 men, mean age 52 years) were allocated additional CDT (n = 50) or standard treatment alone (n = 53). After CDT, grade III (complete) lysis was achieved in 24 and grade II (50%-90%) lysis in 20 patients. One patient suffered major bleeding and two had clinically relevant bleeding related to the CDT procedure. After 6 months, iliofemoral patency was found in 32 (64.0%) in the CDT group vs. 19 (35.8%) controls, corresponding to an absolute risk reduction (RR) of 28.2% (95% CI: 9.7%-46.7%; P = 0.004). Venous obstruction was found in 10 (20.0%) in the CDT group vs. 26 (49.1%) controls; absolute RR 29.1% (95% CI: 20.0%-38.0%; P = 0.004). Femoral venous insufficiency did not differ between the two groups. CONCLUSIONS: After 6 months, additional CDT increased iliofemoral patency from 36% to 64%. The ongoing long-term follow-up of this study will document whether patency is related to improved functional outcome.

Multidetector computed tomography (MDCT) in the diagnosis of pulmonary embolism: interobserver agreement among radiologists with varied levels of experience.

PURPOSE: To assess the interobserver variability of radiologists with varied levels of experience in the interpretation of multidetector computed tomography (MDCT) pulmonary angiographies. MATERIAL AND METHODS: Review of CT pulmonary angiographies performed on patients included in a diagnostic study evaluating a decision-based algorithm for diagnosing pulmonary embolism (PE). Five radiologists, three board-certified general radiologists and two radiology trainees with 2 years' experience, participated in the study. RESULTS: According to the consensus reading, PE was present in 91 (31%) and absent in 194 (67%) patients, while in five patients (1.7%) the interpretations were regarded as equivocal. The per-patient agreement on the diagnosis of PE achieved by each of the four readers compared to the consensus reading was very good (kappa range 0.85-0.92), but peripheral emboli were missed in four to six patients by three of four observers. The agreement on the most proximal level of PE (per-proximal level) assessed by mean kappa value was 0.83 (kappa range 0.68-0.91) for the detection of proximal emboli, 0.61 for segmental emboli (kappa range 0.40-0.80), and 0.38 for emboli in the subsegmental vessels (kappa range 0.0-0.89). CONCLUSION: The overall agreement on the diagnosis of PE by MDCT for general radiologists and radiology trainees is very good, and we therefore believe that the initial management of patients with suspected PE could be based on the preliminary assessment performed by on-call radiologists with 2 years of experience.

The association between the proximal extension of the clot and the severity of pulmonary embolism (PE): a proposal for a new radiological score for PE.

BACKGROUND: The aim of the study was to investigate the association between the proximal level of the clot and the severity of pulmonary embolism (PE). METHODS: The cohort consisted of 99 consecutive patients with PE diagnosed by multi-detector computed tomography. A new score was constructed by calculating the mean value of the largest affected vessel [sub-segmental = 1, segmental = 2, lobar = 3, main pulmonary artery (MPA) = 4] in each lung. RESULTS: A significant association was found between the most proximal level of PE and pulmonary artery obstruction index (PAOI) (P < 0.0001), right ventricular (RV)/left ventricular (LV) ratio (P < 0.0001), and PaO(2) (P = 0.004). No significant association was found between systolic blood pressure and the level of PE. Troponin-T was elevated in none of the sub-segmental, 5% of segmental, 20% of lobar, and in 56% of PEs in the MPA (P = 0.001). Significant association was found between the proposed score and PAOI (P < 0.0001), RV/LV ratio (P < 0.0001), PaO(2) (P < 0.008). Troponin-T was elevated in 10% of level 1, 0% of level 2, 43% level of 3, 66% of level 4 PE (P < 0.0001). Cut-off level score 4 yielded a sensitivity of 84% and a specificity of 74% for the detection of elevated troponin-T. CONCLUSIONS: In conclusion, the study indicates that both the most proximal level of PE and the proposed score are related to the severity of PE as determined by blood oxygenation, biochemical and radiological parameters and could therefore be of value for rapid risk stratification of PE. However, the prognostic value of these classifications and their clinical significance needs to be evaluated in properly designed studies.

D-dimer level is associated with the extent of pulmonary embolism.

OBJECTIVES: Our aim was to study the association between the level of D-dimer and the severity of pulmonary embolism (PE) as determined by various biochemical and radiological prognostic markers in order to investigate the potential value of D-dimer as a prognostic marker for the severity of PE. PATIENTS AND METHODS: PE was diagnosed in 100 consecutive out-patients by multi-detector computerized tomography. One patient was excluded and the final cohort consisted of 99 patients. Pulmonary Artery Obstruction Index (PAOI) and Right Ventricular/Left Ventricular (RV/LV) ratio were assessed. RESULTS: The median value for D-dimer was 5.0 mg/L (inter-quartile range: 1.8, 12.2). There was a significant association between log D-dimer, and between log RV/LV (r=0.45), log PAOI (r=0.5), and PaO(2) (r=0.40). The multivariate analysis showed an increased association between log D-dimer and between log RV/LV ratio (r=0.54) and log PAOI (r=0.52) after adjusting for age, gender and for the duration of symptoms. Significant association was found between the level of D-dimer and the most proximal level of PE (p<0.0005). There was a significant dose-response relationship between the level D-dimer and between Troponin-T and the frequency of thrombolysis (p<0.0005). In the subgroup of patients with D-Dimer over the upper quartile (>12.2), 12 (67%) patients had elevated Troponin-T and 8 (32%) patients received thrombolysis, compared to 1 (5%) patient with elevated Troponin-T and none treated with thrombolysis in the subgroup of patients with D-dimer

Management of suspected pulmonary embolism (PE) by D-dimer and multi-slice computed tomography in outpatients: an outcome study.

OBJECTIVES: A prospective outcome study designed to evaluate a simple strategy for the management of outpatients with suspected pulmonary embolism (PE), based on clinical probability, D-dimer, and multi-slice computed tomography (MSCT). METHODS: A cohort of 432 consecutive patients admitted to the emergency department with suspected PE was managed by sequential non-invasive testing. Patients in whom PE was ruled out were not given anticoagulants, but were followed-up for 3 months. RESULTS: Normal D-dimer and low-intermediate clinical probability ruled out PE in 103 patients [24% (95% CI 20-28)]. Seventeen patients had normal D-dimer, but high clinical probability and proceeded to MSCT. All patients proved negative for PE. A total of 329 (76%) patients underwent MSCT examination. Pulmonary embolism was diagnosed in 93 patients [21.5% (95% CI 18-26)] and was ruled out by negative MSCT in 221 patients [51% (95% CI 46-56)]. MSCT scans were determined as inconclusive in 15 (4.5%) patients. No patient developed objectively verified venous thromboembolism (VTE) during the 3-month follow-up period. However, the cause of death was adjudicated as possibly related to PE in two patients, resulting in an overall 3-month VTE risk of 0.6% (95% CI 0-2.2%). The diagnostic algorithm yielded a definite diagnosis in 96.5% of the patients. CONCLUSIONS: This simple and non-invasive strategy combining clinical probability, D-dimer, and MSCT for the management of outpatients with suspected PE appears to be safe and effective.

Occupational exposure to airborne proteolytic enzymes and lifestyle risk factors for dental erosion--a cross-sectional study.

This study examined the hypothesis that occupational exposure to airborne proteolytic enzymes is associated with dental erosions on the facial surfaces of exposed teeth. Individuals (n = 425) working at a pharmaceutical and biotechnological enterprise (Novozymes A/S) were examined; their mean age was 35 years (range = 18-67 years) and 143 (34%) were women. Two hundred and two of these individuals were newly employed by the company. Occupational exposure was assessed from questionnaire and workplace information. For practical analytical purposes, individuals were categorized as either previously exposed to proteolytic enzymes or not. Information on relevant lifestyle factors and medical history was obtained from a questionnaire. The main effect measure was facial erosion, but lingual erosion indices and the presence of Class V restorations were also considered. The validity of these measures was shown to be very high. Adjusted for potential confounders, there was no association between history of occupational exposure to proteolytic enzymes and prevalent facial or lingual erosion. With respect to prevalence of Class V restorations, the association was significant. The present study did not support directly our primary hypothesis that occupational exposure to airborne proteolytic enzymes is associated with dental erosions on the facial surfaces of exposed teeth. However, the results indicate that exposure to proteolytic enzymes may lead to pronounced tooth substance loss, demanding treatment.

Outbreak of Campylobacter infection in a subartic community.

A presumably waterborne outbreak of Campylobacter jejuni/coli infection in a subarctic community is described. Drinking water supplied to residents was delivered unchlorinated during a 4-week period. No Campylobacter sp. was recovered from the water supply. Three hundred thirty individuals (15% of the 2,200 exposed) became ill. Diarrhoea, abdominal pain, fever, nausea and joint pain occurred in 81%, 30%, 29%, 43% and 21%, respectively. Nine percent reported swelling of joints, and two cases of reactive arthritis occurred. A Campylobacter sp. was isolated from 9 of 33 individuals who became ill and from 1 of 33 healthy controls. All culture-positive individuals, 46% of culture-negative ill persons and 27% of healthy controls were seropositive. All strains recovered had an identical DNA profile.

A polarized light and scanning electron microscopic study of human fissure and lingual enamel of unerupted mandibular third molars.

Using histological and ultrastructural techniques the aims of this study were to investigate whether the mineralization pattern and surface microanatomy of the caries-susceptible fissure enamel were different from those on the caries-inactive lingual surface. The material consisted of 31 unerupted third mandibular molars. The specimens were initially grouped into four categories: (1) without, (2) with initial, (3) with almost completed and (4) with completed root formation. One ground section with fissure-like morphology was selected from each tooth. Using water as a medium the observed birefringence was negative along the lingual and fissure transverses in specimens with almost completed and with completed root formation, while the observed birefringence was positive at different distances in the enamel in sections representing less maturation stages. Qualitative imbibition studies revealed hypomineralized enamel in the lower part of the fissures in specimens representing almost and completed root formation. Imbibed in quinoline, parts of the hypomineralized enamel behaved like a molecular sieve due to the presence of micropores, indicating that the structural arrangement is different from that in the enamel adjacent to this areas. After division of the sections into a lingual and a buccal part, SEM features were described from lower and upper parts of the buccal fissure wall and on lingual enamel in the area corresponding to the bottom part of the fissure. The surface microanatomy varied greatly. Negative developmental irregularities such as fissures and holes were associated with the immature enamel, while matured enamel - particularly fissures - housed many positive developmental irregularities such as enamel caps and protrusions. The crystal size in the mature specimens appeared smaller and more uniform than the crystals from the immature specimens. Apart from the occurrence of hypomineralized enamel in fissures and numerous positive developmental irregularities on the fissure surface, no major differences between fissure and lingual enamel were noticed, neither with respect to mineralization pattern during final stages of tooth development nor to the degree of surface porosity prior to tooth emergence.

Scanning electron microscopy, a useful tool in forensic dental work.

In selected cases there is a need for microscopic information found on the surface of tooth specimens. Scanning electron microscopy is the method of choice. Based on the knowledge of the structural organization of the mineralized dental tissues differential diagnoses of physical and chemical changes can be made. It is suggested that the forensic dental profession cooperates in establishing a collection of reference material illustrating different traumas to enamel and dentin, deposits on teeth and the structure of restorative dental materials as they will appear after some years in position on a tooth. Four different cases are presented.

In vivo caries models--mechanisms for caries initiation and arrestment.

The effects of intra-oral mechanical forces on caries initiation, progression, and arrestment are evaluated by examination of different in vivo caries models. The models are grouped in four categories: (1) a population study, (2) short-term clinical trials, (3) clinical experiments, and (4) controlled clinical observations. Taken together, these in vivo studies convincingly demonstrate that partial or total elimination of the intra-oral mechanical forces operating during mastication or toothbrushing leads to evolution of cariogenic plaque, resulting in localized carious enamel dissolution. In addition, they show that re-exposure to the partly or totally eliminated mechanical forces not only arrests further lesion progression, but also results in partial lesion regression. The data from in vivo caries studies also show that the clinical and structural changes associated with lesion arrestment or partial regression are not related to any salivary repair mechanism, but are solely the result of mechanical removal of the cariogenic biomass which is physically interrelated with the eroded surface of the active, dull-whitish enamel lesion. No indications of superficial mineral deposition or "blocking" of the external intercrystalline spaces are seen in the surface layer of lesions arrested in vivo. For this reason, the conventional usage of the terminology 'remineralization' is considered absolutely misleading when used to describe the mechanisms responsible for the arrest of lesion progression in vivo.

Exaggerated abrasion/erosion of human dental enamel surfaces: a case report.

An atypical, rapidly proceeding abrasion/erosion of the labial enamel surfaces of the maxillary and mandibular incisors and canines in a 27-yr-old man is reported. Ultrastructural examination of a replica of the teeth showed a practically structureless enamel surface both at the initial examination and after 12 months. However, at the end of the period, minor areas of dentin tubules became visible, indicating that a substantial loss of the tooth substance had taken place. The patient's occupation involved daily environmental contact with proteolytic enzymes. In vitro study of enamel exposed to one of the actual proteolytic enzymes showed dissolution of enamel substance, and it cannot be excluded that enzymatic decomposition of the organic enamel matrix is a contributing cause of the observed exaggerated loss of tooth substance.

A light and scanning electron microscopic study of enamel decalcification in children living in a water-fluoridated area.

Eleven children, each having one or two pairs of premolars to be extracted for orthodontic purposes, participated in the study. The model involved placement of a special orthodontic band that allowed the accumulation of plaque in a defined area between the band and the buccal enamel. Examination of enamel changes was carried out in experimental teeth that had been exposed to local plaque accumulation for one, two, four, eight or 14 days. The specimens were examined under the light (LM) and the scanning electron microscope (SEM). All teeth had signs of very mild dental fluorosis. No indications of demineralization were noted after one day. SEM examination showed signs of crystal dissolution in some of the two-day specimens. Six of eight four-day specimens exhibited surface dissolution. All eight- and 14-day specimens showed signs of surface demineralization in the LM as well as in the SEM. These observations documented that undisturbed bacterial deposits are capable of initiating enamel demineralization within short time periods, even in children living in a water-fluoridated area.

The microflora associated with the development of initial enamel decalcification below orthodontic bands in vivo in children living in a fluoridated-water area.

Thirty-four caries-free teeth destined for orthodontic extraction were banded to provide a protected area for the accumulation of plaque. The teeth were extracted at one, two, four, eight, and 14 days after being banded, and samples of the flora below the band were analyzed for the presence of Streptococcus sanguis, Streptococcus 'mitior', 'mutans streptococci', Actinomyces viscosus, Actinomyces naeslundii, Actinomyces odontolyticus, Lactobacillus species, and Veillonella. After plaque sampling, the teeth were sent to the Royal Dental College (Copenhagen) for histological analysis. The results showed that S. mutans could colonize the area below the band after one day, but that colonization was only 100% at 14 days. Lactobacillus was only isolated from 2/8 samples at four days and from 4/8 samples at 14 days. S. sanguis and 'S. mitior' were regularly isolated at all banding times, and Veillonella was isolated from all samples. A. viscosus was the most commonly isolated Actinomyces. The numbers of Streptococcus and Veillonella were significantly higher at day 1 than at day 14 (p less than 0.05). S. mutans and A. viscosus were isolated more frequently at day 14 than at day 1 (p less than 0.01). Histological examination revealed that dissolution of the enamel below a band could occur after two days, but that even after 14 days dissolution could be questionable. Dissolution was detected in areas where S. mutans was not isolated (8/34), but S. mutans was also present in samples showing dissolution (12/34). There was no relationship between dissolution and the numbers of S. mutans; however, the isolation frequency of S. mutans was associated with dissolution (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of regular professional plaque removal on dental caries in vivo. A polarized light and scanning electron microscope study.

This study aims to describe the histological and ultrastructural enamel reactions to regular disturbance/removal of dental plaque, using an in vivo caries model. Fourteen young volunteers undergoing orthodontic treatment participated in the study. To create local protected areas, orthodontic bands with a buccal space were placed in homologous pairs of premolars. One tooth in each pair served as control and had the band cemented for the entire test period of 5 weeks. The other band was removed weekly and the buccal surface cleaned, either by careful pumicing with a nonfluoride toothpaste, or by simple cleaning with a cotton pellet. Results indicated that 5 weeks with completely undisturbed plaque accumulation resulted in visible enamel demineralization in all 14 individuals, whilst a weekly performed professional plaque removal was able to prevent lesion progress independent of the cleaning procedure. It is therefore concluded that regular mechanical disturbance of dental plaque is able to suppress bacterial activity and hence caries development.

Surface changes during the arrest of active enamel carious lesions in vivo. A scanning electron microscope study.

The present study examines early enamel surface alterations taking place when active carious lesions enter an arrested stage. Orthodontic bands with a standardized space for plaque accumulation were used to produce incipient carious lesions on the buccal surface of all four first premolars of four young adolescents. The premolars were to be extracted for orthodontic reasons. After 4 weeks of local cariogenic challenge, all teeth were debanded. In each patient one tooth was extracted at the time of debanding. The remaining premolars were extracted 1, 2, and 3 weeks after re-exposure to the oral environment. No fluoride was added during the entire test period, and the patients were told to maintain usual oral hygiene. Scanning electron microscope examination of the experimental surface areas disclosed a gradual wearing away of the outermost crystals during the 3 weeks of observation. This was associated with a leveling off of surface irregularities and the development of a multitude of scratches. The observed attrition of the porous surface in the lesion area indicates that functional wear and toothbrushing were responsible for the arrestment by disturbance and removal of bacterial deposits.

A scanning electron microscopy study of approximal premolar surfaces from fifteen year old children living in a fluoridated community.

The aim of the present study was to examine approximal enamel surfaces in the scanning electron microscope (SEM). Thirty premolars developed and erupted in an 'optimally' fluoridated (1 ppm) community had clinical indications of dental fluorosis and early signs of dental caries corresponding to the approximal contact area. The SEM-examination disclosed a spectrum of posteruptive changes ranging from isolated surface fractures to carious dissolution, abrasion and calcified microbial deposits. Conclusively, we found that teeth developed and erupted in areas with fluoridated water undergo similar posteruptive alterations due to prevailing environmental conditions as reported in teeth from low fluoride areas.

A polarized light and scanning electron microscope study of the effect of Duraphat treatment on in vivo caries.

The present study was carried out to examine the effect of application of a fluoride varnish (Duraphat) on experimentally produced caries in vivo. After a 4-wk period of cariogenic challenge on homologous pairs of premolars, Duraphat was applied on one of the teeth while the other was extracted and saved as a control. The Duraphat treated teeth remained in a cariogenic environment for a new period of 2 wk prior to extraction. All the control teeth displayed the classical characteristics of active incipient subsurface carious lesions. The Duraphat treated lesions showed an increase in surface porosity relative to their controls while the subsurface porosity was dramatically reduced. When examined in the SEM, the corresponding surface appeared smooth with a leveling out of the original surface irregularities. High power microscopy disclosed, however, a distinct network of intercrystalline spaces. Application of Duraphat prior to reestablishment of cariogenic challenge apparently gives rise to a marked redistribution of minerals in active initial carious lesions.