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Randomized, pilot study of intermittent pneumatic compression devices plus dalteparin versus intermittent pneumatic compression devices plus heparin for prevention of venous thromboembolism in patients undergoing craniotomy.

BACKGROUND: Unfractionated heparin and the low molecular weight heparin, dalteparin, are used for prophylaxis against venous thromboembolism in patients undergoing craniotomy. These drugs were compared in a randomized, prospective pilot study comparing intermittent pneumatic compression devices plus dalteparin to intermittent pneumatic compression devices plus heparin. METHODS: One hundred patients undergoing craniotomy were randomly allocated to receive perioperative prophylaxis with subcutaneous (SC heparin, 5000 units every 12 hours, or dalteparin, 2,500 units once a day, begun at induction of anesthesia and continued for 7 days or until the patient was ambulating. Entry criteria were age over 18 years, no deep vein thrombosis (DVT) preoperatively as judged by lower limb duplex ultrasound and no clinical evidence of pulmonary embolism preoperatively. Patients with hypersensitivity to heparin, penetrating head injury or who refused informed consent were excluded. Patients underwent a duplex study 1 week after surgery and 1 month clinical follow-up. All patients were treated with lower limb intermittent pneumatic compression devices. RESULTS: There were no differences between groups in age, gender, and risk factors for venous thromboembolism. There were no differences between groups in intraoperative blood loss, transfusion requirements or postoperative platelet counts. Two patients receiving dalteparin developed DVT (one symptomatic and one asymptomatic). No patient treated with heparin developed DVT and no patient in either group developed pulmonary embolism. There were two hemorrhages that did not require repeat craniotomy in patients receiving dalteparin and one that did require surgical evacuation in a patient treated with heparin. Drug was stopped in two patients treated with dalteparin because of thrombocytopenia. None of these differences were statistically significant. CONCLUSION: There was no significant difference in postoperative hemorrhage, venous thromboembolism or thrombocytopenia between heparin and dalteparin. The results suggest that, given the small sample size of this trial, both drugs appear to be safe and the incidence of venous thromboembolism by postoperative screening duplex ultrasound appears to be low when these agents are used in combination with intermittent pneumatic compression devices.

Adult↗

Risk of venous thromboembolism with cyproterone or levonorgestrel contraceptives.

Results of studies have shown that there is an excess risk of venous thromboembolism in users of oral contraceptives containing cyproterone compared with those containing levonorgestrel. We did a case-control study, in which we assessed the risk of idiopathic venous thromboembolism in women taking combined low-dose oestrogen oral contraceptives containing cyproterone (n=24401) or levonorgestrel (n=75000). We compared the 26 women in this population who had idiopathic venous thromboembolism with 144 matched controls. 12 individuals and 30 controls were taking contraceptives that contained cyproterone. Our results suggest that risk of venous thromboembolism is increased four-fold in women taking contraceptives containing cyproterone by comparison with those exposed to levonorgestrel.

Adult↗

Postoperative fondaparinux versus preoperative enoxaparin for prevention of venous thromboembolism in elective hip-replacement surgery: a randomised double-blind comparison.

BACKGROUND: Despite use of thromboprophylaxis, elective hip-replacement surgery carries a high risk of venous thromboembolic complications. We aimed to assess the ability of the pentasaccharide fondaparinux, the first of a new class of synthetic antithrombotic agents, to further reduce this risk. METHODS: In a double-blind study, we randomly assigned 2309 consecutive patients aged 18 years or older who were undergoing elective hip-replacement surgery to once daily, subcutaneous injections of either 2.5 mg fondaparinux, starting postoperatively, or 40 mg enoxaparin, starting preoperatively. The primary efficacy outcome was venous thromboembolism up to day 11, defined as deep-vein thrombosis detected by mandatory bilateral venography, documented symptomatic deep-vein thrombosis, or documented symptomatic pulmonary embolism. The main safety outcomes were bleeding and death. The duration of follow-up was 6 weeks. Analysis was per protocol. FINDINGS: We assessed the primary efficacy outcome in 1827 (79%) of 2309 patients. By day 11, venous thromboembolisms were recorded in 37 (4%) of 908 patients assigned to fondaparinux and in 85 (9%) of 919 assigned to enoxaparin (difference -5.2% [95% CI -8.1 to -2.7], p<0.0001). The relative reduction in risk was 55.9% (95% CI 33.1-72.8). The two groups did not differ in frequency of death or clinically relevant bleeding. INTERPRETATION: Drugs that act through specific inhibition of factor Xa, such as fondaparinux, could be more effective than low molecular weight heparins in prevention of venous thromboembolism in patients undergoing hip-replacement surgery.

Adult↗

Serial changes in negative T wave on electrocardiogram in acute pulmonary thromboembolism.

A negative T wave is frequently observed in precordial ECG leads in patients with acute pulmonary thromboembolism. We investigated the clinical significance of negative T wave in 15 patients with acute pulmonary thromboembolism who were treated with thrombolytic agents by measuring the mean pulmonary artery pressure and ratio of right to left ventricular end-diastolic diameter using echocardiography and ECG. The study included only patients with massive acute pulmonary thromboembolism of a mean age of 65+/-9.7 years (+/-SD). A negative T wave was observed on admission in 10 patients but was later detected in 14 of the 15 patients. The mean amplitude of the negative T wave increased within 1 week then decreased after thrombolytic treatment. The peak negative amplitude of the T wave was observed from 1 to 7 days (mean, 2.6+/-1.8 days) and disappeared afterwards. During this period, improvements in both the mean pulmonary artery pressure (37.8+/-11.2 to 19.1+/-6.7 mmHg) and the ratio of right to left ventricular end-diastolic diameter (0.97+/-0.16 to 0.51+/-0.13) were noted in all patients. Our results suggest that an increase in the amplitude of negative T wave in precordial leads after thrombolytic therapy in patients with massive acute pulmonary thromboembolism reflects improvement in cardiopulmonary hemodynamics.

Aged↗

Pulmonary artery pulse pressure and wave reflection in chronic pulmonary thromboembolism and primary pulmonary hypertension.

OBJECTIVES: The purpose of this time-domain study was to compare pulmonary artery (PA) pulse pressure and wave reflection in chronic pulmonary thromboembolism (CPTE) and primary pulmonary hypertension (PPH). BACKGROUND: Pulmonary artery pressure waveform analysis provides a simple and accurate estimation of right ventricular afterload in the time-domain. Chronic pulmonary thromboembolism and PPH are both responsible for severe pulmonary hypertension. Chronic pulmonary thromboembolism and PPH predominantly involve proximal and distal arteries, respectively, and may lead to differences in PA pressure waveform. METHODS: High-fidelity PA pressure was recorded in 14 patients (7 men/7 women, 46 +/- 14 years) with CPTE (n = 7) and PPH (n = 7). We measured thermodilution cardiac output, mean PA pressure (MPAP), PA pulse pressure (PAPP = systolic - diastolic PAP) and normalized PAPP (nPAPP = PPAP/MPAP). Wave reflection was quantified by measuring Ti, that is, the time between pressure upstroke and the systolic inflection point (Pi), deltaP, that is, the systolic PAP minus Pi difference, and the augmentation index (deltaP/PPAP). RESULTS: At baseline, CPTE and PPH had similar cardiac index (2.4 +/- 0.4 vs. 2.5 +/- 0.5 l/min/m2), mean PAP (59 +/- 9 vs. 59 +/- 10 mm Hg), PPAP (57 +/- 13 vs. 53 +/- 13 mm Hg) and nPPAP (0.97 +/- 0.16 vs. 0.89 +/- 0.13). Chronic pulmonary thromboembolism had shorter Ti (90 +/- 17 vs. 126 +/- 16 ms, p < 0.01) and higher deltaP/PPAP (0.26 +/- 0.01 vs. 0.09 +/- 0.07, p < 0.01). CONCLUSIONS: Our study indicated that: 1) CPTE and PPH with severe pulmonary hypertension had similar PA pulse pressure, and 2) wave reflection is elevated in both groups, and CPTE had increased and anticipated wave reflection as compared with PPH, thus suggesting differences in the pulsatile component of right ventricular afterload.

Adult↗

Venous thromboembolism prevention in surgery and obstetrics: clinical practice guidelines.

BACKGROUND AND OBJECTIVE: To produce up-to-date clinical practice guidelines on the prevention of venous thromboembolism in surgery and obstetrics. METHODS: A Steering Committee defined the scope of the topic, the questions to be answered, and the assessment criteria. Eight multidisciplinary working groups (total of 70 experts) performed a critical appraisal of the literature in the following disciplines: pharmacology of antithrombotic agents, orthopaedics; general surgery (gastrointestinal (GI) and varicose vein surgery); urology; gynaecology and obstetrics; thoracic, cardiac and vascular surgery; surgery of the head, neck and spine; and surgery of burns patients. The resultant reports and guidelines were submitted for comment and completion of the Appraisal of Guidelines Research & Evaluation questionnaire to a total of 150 peer reviewers, before producing definite guidelines. RESULTS: The report answers the following questions for each type of surgery: (i) What is the venous thromboembolism incidence according to clinical and/or paraclinical criteria in the absence of prophylaxis? (with stratification of venous thromboembolism risk into low, moderate and high categories); (ii) What is the efficacy and safety of the prophylactic measures used? (iii) When should prophylaxis be introduced and how long should it last? (iv) Does ambulatory surgery affect efficacy and safety of prophylaxis? CONCLUSIONS: Apart from answering the above questions, the guidelines provide a summary table for each discipline. This table stratifies types of surgery into the three risk categories, specifies the recommended prophylaxis for venous thromboembolism (pharmacological and/or mechanical) and grades each recommendation. In addition, whenever appropriate, the recommended prophylaxis is adjusted to low- and high-risk patients.

Anticoagulants↗

Venous thromboembolism occurs frequently in patients undergoing brain tumor surgery despite prophylaxis.

Most Neurosurgical Service patients at our hospital receive venous thromboembolism prophylaxis. In 1995-96, the rate of clinically overt venous thromboembolism was 3.7% among patients undergoing neurosurgery. However, rates were much higher when craniotomy was undertaken for brain tumor. Of 497 who underwent craniotomy for primary (429) or metastatic (68) brain tumor, 47 (9.5%) developed clinically overt venous thromboembolism: 7.5% after primary brain tumor resection and 19% after craniotomy for metastatic cancer. The high rate of venous thromboembolism in craniotomy patients with brain tumor warrants study of alternative measures for preventing thrombus, such as prophylaxis with low molecular weight heparin.

Brain Neoplasms↗

Practices in the Prevention of Venous Thromboembolism.

Objective: The objective of this study was to determine the proportion of Massachusetts Medicare patients who received prophylaxis for venous thromboembolism following colectomy, hysterectomy, or total hip arthroplasty. Sample frame: All 90 Massachusetts acute care hospitals. Time frame: 1 April through 30 September, 1994. Target population: Patients discharged with an International Classification of Disease (ICD-9-CM) discharge diagnostic code (recorded in the Massachusetts Medicare Claims Database) for colectomy, hysterectomy, or total hip arthroplasty were used to identify the target patient population. Sample population: 1,397 patients randomly selected from the target population, including 467 total hip arthroplasties, 474 colectomies, and 456 hysterectomies. Data extraction: Medical records were reviewed by trained nurse abstractors who collected information on the use of prophylaxis for venous thromboembolism. Results: Prophylaxis for venous thromboembolism was employed by surgeons practicing in Massachusetts hospitals in 93% of total hip arthroplasty cases (regional variation 85-98%), 84% of colectomies (regional variation 57-93%), 66% of hysterectomies (regional variation 35-71%), and in 87% of the subset of 111 hysterectomies with malignancy (regional variation 25-100%). Conclusions: The results of this statewide study demonstrated significant regional and hospital-to-hospital variation in the use of prophylaxis for venous thromboembolism following major surgery. A lower rate of prophylaxis use was observed in hospitals with fewer than 200 beds and in hospitals that did not have teaching programs. Hospitals with below-average rates of prophylaxis were targeted for intensive quality improvement interventions.

Journal Article↗

A simple venous thromboembolism prophylaxis protocol for patients undergoing bariatric surgery.

OBJECTIVE: Pulmonary embolism is a leading cause of death for bariatric patients. Numerous regimens have been proposed, but a comprehensive, simple approach is lacking. This study provides a simple, easily implemented prophylaxis regimen. RESEARCH METHODS AND PROCEDURES: One hundred fifty bariatric surgery patients were evaluated. Patients considered at high risk for venous thromboembolism had heart failure, a BMI of >/=50 kg/m(2), or a history of venous thromboembolism or pelvic surgery. Preoperatively and postoperatively, all patients received subcutaneous enoxaparin or unfractionated heparin. High-risk patients received either preoperatively inserted inferior vena cava filters or continuous heparin infusions intraoperatively. All high-risk patients were anticoagulated with warfarin (Coumadin; Bristol Myers-Squibb, Princeton, NJ) for at least 3 months postoperatively. Initially, some patients experienced significant hemorrhage; to prevent this, sutures were oversewn into staple lines. RESULTS: No patient experienced venous thromboembolism; a binomial test showed that the regimen reduced the risk of this complication to less than 2% (p < 0.05). Hemorrhage sufficient to require transfusion occurred in 4 of the first 20 patients; of the remaining 130 patients, into whose staple lines sutures were oversewn, none required transfusion (p < 0.05). DISCUSSION: Patients should be divided into those who are at high risk and those who are at low risk for venous thromboembolism. All patients should receive pre- and postoperative anticoagulation. High-risk patients should also receive either an inferior vena cava filter or intraoperative heparin infusions, as well as at least 3 months of Coumadin therapy. Oversewing of staple lines may reduce the risk of hemorrhage.

Anticoagulants↗

Increased thromboxane production in women with a history of venous thromboembolic event: effect of heparins.

We investigated the production of prostacyclin and thromboxane in pregnant women with a previous venous thromboembolic event before, during and after the use of unfractionated heparin and low molecular weight heparin (dalteparin). Twenty women were studied before starting heparin prophylaxis (before 20 weeks of gestation), during heparin prophylaxis (at 30 weeks of gestation) and after heparin prophylaxis (16 weeks after delivery). Ten pregnant women with no history of thromboembolism were studied as the control group. Urinary output of the stable metabolite of prostacyclin (2,3-dinor-6-keto-PGF1alpha) and that of thromboxane A2 (2,3-dinor-TxB2), as well as a number of markers of thrombophilia were measured and expressed as mean (+/-SEM). Women with a history of thromboembolism were characterized by normal prostacyclin production but elevated thromboxane production (44.0 +/- 4.1 versus 19.0 +/- 3.6 ng/mmol creatinine, P < 0.001) at 12 weeks of pregnancy. Heparin prophylaxis (regardless of the type) had abolished elevated thromboxane concentrations at 30 weeks of gestation. Four months after delivery, thromboxane dominance had returned (25.2 +/- 3.5 versus 13.6 +/- 2.1 ng/mmol creatinine, P < 0.01). The presence of hereditary thrombophilia (9/20) was not associated with any changes in prostanoid concentrations. Thus, women with a history of venous thromboembolic events have thromboxane dominance during and after pregnancy, but this dominance can be eliminated through the use of heparins.

6-Ketoprostaglandin F1 alpha↗

D-dimer for the exclusion of venous thromboembolism: comparison of a new automated latex particle immunoassay (MDA D-dimer) with an established enzyme-linked fluorescent assay (VIDAS D-dimer).

The use of D-dimer tests to exclude venous thromboembolism is an important advance in clinical practice and also has economic benefits. Ideally the test should be objective and a test that could be run on the routine coagulometer would obviate the need for additional investment in alternative hardware. A new automated latex particle immunoassay (MDA D-dimer) that can be run on a routine coagulometer was compared with a well established enzyme linked fluorescent assay (VIDAS D-dimer) on the basis of their ability to exclude venous thromboembolism. The assays were compared in 49 patients presenting to the emergency department with clinically suspected deep vein thrombosis or pulmonary embolism. After objective diagnostic imaging, 20 patients were confirmed to have venous thromboembolism. There was strong agreement between the assays in individual patients. Using a cut-off of 500 micrograms/l, both tests had a sensitivity of 100% and therefore a negative predictive value of 100%, however the MDA test would have spared more patients (20% vs. 12%) from further testing if a negative D-dimer was used to rule-out the diagnosis. It was concluded that a rapid, objective latex D-dimer test run on a routine coagulometer (MDA D-dimer) can be used to exclude the diagnosis of venous thromboembolism.

Enzyme-Linked Immunosorbent Assay↗

Incidence of venous thromboembolic events among nursing home residents.

Chronic care facility stay has been shown to be an independent risk factor for venous thromboembolism. Review of the literature, however, reveals a paucity of data addressing the issue of venous thromboembolism in nursing home residents. The purpose of this study was to determine the incidence of venous thromboembolic events among nursing home residents. A retrospective cohort study was derived from data compiled in the State of Kansas Minimum Data Set (MDS) for nursing home residents from July 1, 1997 to July 1, 1998. A total of 18,661 residents (median age, 85 years, 74% female, 95% white) satisfied the study criteria. The outcome measures of the primary endpoint-development of a venous thromboembolic event (VTE)-were obtained from the MDS quarterly health assessments and the Medicare ICD-9 codes. We determined the incidence of VTE among nursing home residents as 1.30 events per 100 person-years of observation.

Aged↗

Venous thromboembolism as first manifestation of cancer.

Numerous studies, performed in recent years, have provided the convincing demonstration that the incidence of newly diagnosed malignancy is increased among patients with unexplained venous thromboembolism during the first 6 to 12 months after the thromboembolic event. Among malignancies presenting with venous thromboembolism as a first clinical manifestation, prostate and colorectal cancer are the most commonly identified. Other common sites are cancer of the lung, pancreas, stomach, ovary, brain, and bladder. Extensive screening with computer tomography scanning, gastrointestinal endoscopy, and a number of tumor markers have the potential to detect occult malignancies. However, whether an extensive diagnostic work-up in all patients presenting with unexplained venous thromboembolism is cost-effective still remains to be demonstrated.

Humans↗

A comparison of six weeks with six months of oral anticoagulant therapy after a first episode of venous thromboembolism. Duration of Anticoagulation Trial Study Group.

BACKGROUND: The optimal duration of oral anticoagulant therapy after a first episode of venous thromboembolism is still a matter of debate. METHODS: We performed a multicenter trial comparing six weeks of oral anticoagulant treatment with six months of such therapy in patients who had a first episode of venous thromboembolism. Anticoagulant therapy consisted of warfarin or dicumarol. Of the 902 patients enrolled, 5 were later excluded because they had congenital protein C deficiency; 443 were randomly assigned to receive six weeks of oral anticoagulant therapy with a targeted international normalized ratio (INR) of 2.0 to 2.85, and 454 were randomly assigned to receive six months of such therapy. The initial diagnoses were confirmed by means of venography in cases of deep-vein thromboses (n = 790) and with perfusion-ventilation scanning or angiography in cases of pulmonary embolism (n = 107); recurrences were confirmed in the same way. RESULTS: After two years of follow-up, there had been 123 recurrences of venous thromboembolism that met the diagnostic criteria, 80 in the six-week group (18.1 percent; 95 percent confidence interval, 14.5 to 21.6) and 43 in the six-month group (9.5 percent; 95 percent confidence interval, 6.8 to 12.2). The odds ratio for recurrence in the six-week group was 2.1 (95 percent confidence interval, 1.4 to 3.1). There was no difference in mortality or the rate of major hemorrhage between the six-week and six-month groups. CONCLUSIONS: Six months of prophylactic oral anticoagulation after a first episode of venous thromboembolism led to a lower recurrence rate than did treatment lasting for six weeks. The difference between the two groups occurred between 6 weeks and 6 months after the start of treatment, and the rates of recurrence remained nearly parallel for 1 1/2 years thereafter.

Anticoagulants↗

The duration of oral anticoagulant therapy after a second episode of venous thromboembolism. The Duration of Anticoagulation Trial Study Group.

BACKGROUND: A consensus has not been reached about the optimal duration of oral anticoagulant therapy after a second episode of venous thromboembolism. METHODS: In a multicenter trial, we compared six months of oral anticoagulant therapy with anticoagulant therapy continued indefinitely in patients who had had a second episode of venous thromboembolism. Of 227 patients enrolled, 111 were randomly assigned to six months of anticoagulation and 116 were assigned to receive anticoagulant therapy indefinitely; for both groups, the target international normalized ratio was 2.0 to 2.85. The initial episodes of deep-vein thrombosis (n = 193) and pulmonary embolism (n = 34), as well as recurrent episodes, were all objectively confirmed. RESULTS: After four years of follow-up, there were 26 recurrences of venous thromboembolism that fulfilled the diagnostic criteria, 23 in the group assigned to six months of therapy (20.7 percent) and 3 in the group assigned to continuing therapy (2.6 percent). The relative risk of recurrence in the group assigned to six months of therapy, as compared with the group assigned to therapy of indefinite duration, was 8.0 (95 percent confidence interval, 2.5 to 25.9). There were 13 major hemorrhages, 3 in the six-month group, (2.7 percent) and 10 in the infinite-treatment group (8.6 percent). The relative risk of major hemorrhage in the six-month group, as compared with the infinite-treatment group was 0.3 (95 percent confidence interval, 0.1 to 1.1). There was no difference in mortality between the two groups. CONCLUSIONS: Prophylactic oral anticoagulation that was continued for an indefinite period after a second episode of venous thromboembolism was associated with a much lower rate of recurrence during four years of follow-up than treatment for six months. However, there was a trend toward a higher risk of major hemorrhage when anticoagulation was continued indefinitely.

Administration, Oral↗

The prevalence of thromboembolic events among women with extended bed rest prescribed as part of the treatment for premature labor or preterm premature rupture of membranes.

OBJECTIVE: This study was undertaken to determine the prevalence of thromboembolic events among women with extended bed rest prescribed as part of the treatment of premature labor or preterm premature rupture of membranes. STUDY DESIGN: A retrospective chart review was undertaken of all women who had bed rest of >/=3 days' duration prescribed as part of the treatment of premature labor or preterm premature rupture of membranes in the Akron General Medical Center Perinatal Unit during the period January 1, 1997-December 31, 1998. The prevalence of thromboembolic events in this population was determined. The charts of all additional gravid women with antepartum or postpartum deep vein thrombosis or pulmonary embolism diagnosed during the study period were also reviewed. The prevalence of these disorders among the pregnant population for whom extended bed rest was not prescribed as part of the treatment of premature labor or preterm premature rupture of membranes was also calculated. Statistical comparison of the prevalences in the 2 populations was undertaken by means of the chi(2) analysis with the Fisher exact test. RESULTS: There were 192 patients admitted during the study period who had extended bed rest prescribed as part of the treatment of premature labor or preterm premature rupture of membranes. Three of these women had thromboembolic events, for a prevalence of 15.6 cases per 1000 women. Five additional gravid women were admitted for the treatment of deep vein thrombosis or pulmonary embolism. There were 6164 deliveries among women not treated with extended bed rest for premature labor or preterm premature rupture of membranes during this period. Thus the prevalence of these phenomena among the remaining pregnant women was 0.8 cases per 1000 women. The prevalences of these disorders in the 2 populations were highly significantly different. CONCLUSION: The prevalence of thromboembolic events among women for whom extended bed rest is prescribed as part of the treatment of premature labor or preterm premature rupture of membranes is significantly increased with respect to that among gravid women who do not receive this therapy and is substantially higher than previously reported. If this finding is confirmed in other populations, it may be prudent to undertake further studies to determine whether this prevalence can be reduced.

Bed Rest↗

Recurrent thromboembolism in patients with vena cava filters.

BACKGROUND: Patients with venous thromboembolic disease are treated with anticoagulation or vena cava filter placement to prevent pulmonary embolism. A recent report suggested that filter placement may increase the risk of recurrent deep venous thrombosis (DVT) and prompted a review of our experience. METHODS: Prospectively collected data on 2109 consecutive patients receiving filters were evaluated for recurrent thromboembolism, vena cava occlusion, or venous stasis ulceration. Outcomes were stratified and analyzed according to the use of anticoagulants at the time of insertion and at follow-up. Incidence rates were also compared with reports in the literature. RESULTS: Of 1191 patients with DVT at filter placement, complete follow-up data at a mean of 9 years were available for 465. Recurrent DVT was found in 12% of the 241 patients who were given anticoagulants and 15% of the 224 who were not (P >.05). We also failed to find a significant association between the use of anticoagulation and the incidence of pulmonary embolism (2%), stasis ulceration (2%), and vena cava occlusion (0.0). CONCLUSIONS: Recurrent DVT in patients with existing thromboembolic disease is not an unexpected event, which, in our experience, is not associated with anticoagulant or filter use. Anticoagulation should be used when possible to treat existing DVT to reduce thrombus progression and potentially to reduce subsequent complications but does not seem to reduce the rate of recurrent DVT. Rates of recurrent thromboembolism were consistently less than the 20% to 50% reported in the literature.

Adolescent↗

Systematic study of occult pulmonary thromboembolism in patients with deep venous thrombosis.

PURPOSE: This study was carried out to evaluate the prevalence and extension of pulmonary thromboembolism (PTE) in symptom-free patients with symptomatic deep venous thrombosis (DVT) of lower limbs and to evaluate their possible implication in the adequate treatment of thromboembolic disease. MATERIALS AND METHODS: We prospectively studied, using noninvasive examination (pulmonary spiral computed tomography [CT] angiography), 159 consecutive patients with acute DVT confirmed by duplex scanning without symptoms of PTE. CT was repeated at 30 days to study evolution of these clinically occult PTE. RESULTS: We observed silent PTE in 65 patients (41%) in all levels of lower limb venous thrombosis. Prevalence of PTE showed significant association with male sex (P =.001) and previously diagnosed heart disease (P =.023). There was no significant association between the level of DVT and the presence of PTE nor the DVT side and thromboembolic pulmonary localization. Of the 65 patients with positive CT exploration results for PTE, 52 had characteristics of acute PTE, 10 had chronic PTE, and 3 patients had both. Chronic PTE was found more frequently in patients with previous episodes of DVT (P =.024). A total of 165 pulmonary artery-affected segments were found at several locations: 5 main, 35 lobar, 58 interlobar, and 67 segmental. Multiple segments were affected in 59% of patients. Repeat CT examinations were performed at 30 days in 53 of 65 patients with positive CT scanning results. In 48 cases (90.6%) PTE had completely disappeared. CONCLUSIONS: Silent PTE occurred frequently in association with clots of lower limbs. The CT scan had a good availability and cost-effectiveness to detect clinically underestimated PTE. The incorporation of this exploration in the systematic diagnostic strategy of most patients with DVT to establish the extension of thromboembolic disease at diagnosis may be useful in the evaluation of added pulmonary artery symptoms and treatment strategies.

Adolescent↗