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A retrospective study of vein thrombosis in horses treated with intravenous fluids in a veterinary teaching hospital.

The medical records of 68 horses treated with IV fluids for 24 hours or more were reviewed to determine the risk of vein thrombosis and to determine which factors were associated with the occurrence of vein thrombosis in these horses. Three factors were positively associated with vein thrombosis including use of locally produced fluids and presence of fever and diarrhea. Two factors, having general anesthesia or having surgery, were negatively associated with vein thrombosis. One continuous variable, duration of treatment, was positively associated with vein thrombosis. Factors not associated with vein thrombosis included breed, age, sex, type of catheter, outcome (lived or died), laminitis, colic, other drugs via the catheter, and type of surgery. One type of catheter was used in the majority of horses (57) making it difficult to detect effect of catheter type. Preparation of the catheter site, the person placing the catheter, and technique of catheter maintenance were not evaluated. Like all retrospective studies, this study has limitations to the conclusions that can be made; however, the strong association between source of fluids, fever, diarrhea, anesthesia/surgery, and the occurrence of vein thrombosis merits consideration in the clinician's therapeutic plan.

Animals↗

Prevention of deep vein thrombosis after hip replacement: randomised comparison between unfractionated heparin and low molecular weight heparin.

OBJECTIVE: To evaluate the efficacy and safety of two subcutaneous prophylactic regimens for postoperative deep vein thrombosis after total hip replacement. DESIGN: Prospective open randomised multicentre trial. SETTING: 28 European departments of orthopaedic surgery. INTERVENTION: All patients had bilateral phlebography 10 days after surgery. 31 patients receiving low molecular weight heparin and 29 receiving unfractionated heparin were excluded from the efficacy analysis for various reasons. PATIENTS: 349 patients undergoing total hip replacement between September 1988 and May 1989. 174 patients received subcutaneously a low molecular weight heparin (Fraxiparine) with anti-factor Xa activity of 41 IU/kg/day for three days, then 62 IU/kg/day from day 4 to day 10. 175 patients received subcutaneous unfractionated heparin at intervals of eight hours; doses were adjusted to maintain the activated thromboplastin time at two to five seconds above control values. MAIN OUTCOME MEASURE: Total incidence of deep vein thrombosis and incidence of proximal deep vein thrombosis on bilateral phlebography. RESULTS: The total incidence of deep vein thrombosis was 16% in patients receiving unfractionated heparin and 12.6% in patients receiving low molecular weight heparin (p = 0.45), and the incidence of thrombosis of the proximal veins was 13.1% and 2.9% respectively (p less than 0.001). Four patients receiving unfractionated heparin and one receiving low molecular weight heparin developed pulmonary embolism. The incidence of bleeding complications was low and comparable in the two groups. CONCLUSION: Low molecular weight heparin is at least as effective as unfractionated heparin in preventing deep vein thrombosis and is more effective at preventing thrombosis of the proximal veins in patients undergoing hip replacement. Low molecular weight heparin is not more likely to cause bleeding complications and is simpler to give than unfractionated heparin.

Blood Coagulation↗

Application of real-time ultrasonography for the detection of tarsal vein thrombosis in cattle.

The clinical and ultrasonographic features of the thrombosis of three tarsal veins in a six-year-old dairy cow are described. Thrombosis and metastatic abscessation developed on the left tarsus six days after the amputation of the lateral claw of the left hindlimb. Originally, the cow suffered from a severe purulent arthritis of the distal interphalangeal joint and a retroarticular abscess, caused by interdigital necrobacillosis. By means of real-time ultrasonography, using a 7.5 MHz transducer, a marked subcutaneous oedema, a subcutaneous abscess, and a thrombosis of the ramus cranialis and ramus caudalis of the vena saphena lateralis reaching the confluence into the vena saphena lateralis and a thrombosis of the ramus caudalis of the vena saphena medialis could be identified. The thrombosed veins were not compressible, were oval and had an increased diameter of up to 9 x 12 mm. Intraluminal masses were visualised as hypoechoic structures and the veins distal to the thrombosis were distended up to 10 x 13 mm. The differential diagnosis and pathogenesis of the thrombosis and the abscessation are discussed, and the clinical course and the sonographic observations of the thrombosis during a six week period are described.

Abscess↗

Orgaran in the prevention of deep vein thrombosis in stroke patients.

Venous thrombo-embolism is a common complication in patients with acute ischaemic stroke. Without prophylaxis, deep vein thrombosis occurs in 60-75% of patients with dense hemiplegia, usually in the paralyzed limb, and 1-2% suffer fatal pulmonary embolism. Orgaran (Org 10172, low-molecular-weight heparinoid) has been evaluated for the prevention of deep vein thrombosis in patients with acute ischaemic stroke in two studies. In a double-blind study, 75 patients were randomized to receive Orgaran (50 patients) in a loading dose of 1,000 anti-Xa units intravenously followed by 750 anti-Xa units subcutaneously 12-hourly or placebo (25 patients). Deep vein thrombosis occurred in 2 of 50 (4%) in the Orgaran group and 7 of 25 (28%) in the placebo group (p = 0.005). The corresponding rates for proximal deep vein thrombosis were 0 and 16%, respectively (p = 0.01). There was one major haemorrhage in the treated group and one minor haemorrhage in the placebo group. In the second study, the safety and efficacy of Orgaran was compared with unfractionated heparin in the prevention of deep vein thrombosis in a double-blind randomized trial. Eighty-seven patients with marked lower limb paralysis secondary to stroke were randomized to receive Orgaran (45 patients) in a dose of 750 anti-factor Xa units subcutaneously 12-hourly or unfractionated heparin (42 patients) in a dose of 5,000 units subcutaneously 12-hourly. Venous thrombosis occurred in 4 of 45 (8.9%) of the Orgaran group and 13 of 42 (31%) in the unfractionated heparin group (2p = 0.014). The corresponding rates for proximal vein thrombosis were 4.4 and 11.9%, respectively (2p = 0.255).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Deciphering mesenteric venous thrombosis: imaging and treatment.

The principal cause of a high mortality rate in mesenteric vein thrombosis (MVT) is a delay in diagnosis. Recent data indicate that the mortality rate is decreasing owing to earlier diagnosis and anticoagulation. The authors examined the treatment profile of MVT to see how the increased use of imaging and early anticoagulation has impacted this process. They retrospectively analyzed the treatment paradigm with acute MVT at one institution over a 10-year period. Twenty-three patients were identified. Data were analyzed using chi-squares and Student's t tests. Twenty-three patients (11 men and 12 women with an average age of 51.74 +/-14.8 years) were identified with acute MVT between the years of 1993 and 2003. Five patients had splenic vein thrombosis, 17 had superior mesenteric vein thrombosis, 1 had inferior mesenteric vein thrombosis, and 12 had portal vein thrombosis. Nine patients had combination mesenteric vein segment thrombosis. Thrombolytics were utilized in a total of 6 patients. Four of the 6 patients in whom lytics were utilized had combined mesenteric vein thrombosis; however, these 4 patients did not require surgical intervention. There was no significant difference in length of hospital stay between patients taking lytics versus patients treated with traditional anticoagulation with heparin (p = 0.291). A hypercoagulable state was identified in 66.7% of the patients. Four patients required surgical intervention. The overall mortality rate was 8.7% (2 of 23). The use of thrombolytics was associated with a significant mortality (p = 0.04). The use of antibiotics made no difference in mortality (p = 0.235), nor did antibiotic use influence length of hospitalization (p = 0.192). MVT is relatively rare, and often the delay in diagnosis increases the mortality rate. In the majority of cases prompt anticoagulation will preserve bowel viability and decrease mortality and morbidity rates. The majority of patients do not need surgery. There is a marked increase in mortality rate when these patients progress to surgical intervention. An increased awareness and early diagnosis has led to decreased morbidity and mortality rates.

Acute Disease↗

Genetic background determines response to hemostasis and thrombosis.

BACKGROUND: Thrombosis is the fatal and disabling consequence of cardiovascular diseases, the leading cause of mortality and morbidity in Western countries. Two inbred mouse strains, C57BL/6J and A/J, have marked differences in susceptibility to obesity, atherosclerosis, and vessel remodeling. However, it is unclear how these diverse genetic backgrounds influence pathways known to regulate thrombosis and hemostasis. The objective of this study was to evaluate thrombosis and hemostasis in these two inbred strains and determine the phenotypic response of A/J chromosomes in the C57BL/6J background. METHODS: A/J and C57Bl/6J mice were evaluated for differences in thrombosis and hemostasis. A thrombus was induced in the carotid artery by application of the exposed carotid to ferric chloride and blood flow measured until the vessel occluded. Bleeding and rebleeding times, as surrogate markers for thrombosis and hemostasis, were determined after clipping the tail and placing in warm saline. Twenty-one chromosome substitution strains, A/J chromosomes in a C57BL/6J background, were screened for response to the tail bleeding assay. RESULTS: Thrombus occlusion time was markedly decreased in the A/J mice compared to C57BL/6J mice. Tail bleeding time was similar in the two strains, but rebleeding time was markedly increased in the A/J mice compared to C57BL/6J mice. Coagulation times and tail morphology were similar, but tail collagen content was higher in A/J than C57BL/6J mice. Three chromosome substitution strains, B6-Chr5A/J, B6-Chr11A/J, and B6-Chr17A/J, were identified with increased rebleeding time, a phenotype similar to A/J mice. Mice heterosomic for chromosomes 5 or 17 had rebleeding times similar to C57BL/6J mice, but when these two chromosome substitution strains, B6-Chr5A/J and B6-Chr17A/J, were crossed, the A/J phenotype was restored in these doubly heterosomic progeny. CONCLUSION: These results indicate that susceptibility to arterial thrombosis and haemostasis is remarkably different in C57BL/and A/J mice. Three A/J chromosome substitution strains were identified that expressed a phenotype similar to A/J for rebleeding, the C57Bl/6J background could modify the A/J phenotype, and the combination of two A/J QTL could restore the phenotype. The diverse genetic backgrounds and differences in response to vascular injury induced thrombosis and the tail bleeding assay, suggest the potential for identifying novel genetic determinants of thrombotic risk.

Journal Article↗

Factors influencing deep vein thrombosis following total hip arthroplasty under epidural anesthesia.

To determine intraoperative factors which may influence deep vein thrombosis rate, we studied surgeries performed by one surgeon on 441 consecutive patients undergoing primary total hip arthroplasty under epidural anesthesia. Operative limb venography was performed on the fourth or fifth postoperative day in 381 patients, who received 650 mg of aspirin daily as the only postoperative thromboprophylaxis. Of 381 (15%) patients, 58 had a positive venogram; 13 (3%) had proximal thrombi. Of 178 patients (9.5%) with surgery lasting less than 70 min, 17 developed deep vein thrombosis whereas 41 of 203 patients (20.3%) with surgery lasting more than 70 min developed deep vein thrombosis (P < 0.05). Corresponding proximal deep vein thrombosis rates increased from 1.7% to 4.9%. Deep vein thrombosis was observed in 12.5% of patients receiving intravenous low-dose epinephrine, 10.3% receiving intravenous sodium nitroprusside, 14.5% receiving both low-dose epinephrine and sodium nitroprusside concurrently, and 25% receiving intravenous fluid alone. Proximal deep vein thrombosis rates were 2.4%, 0%, 1.45%, and 9.3% in these groups, respectively. These data suggest that the intraoperative management of both surgery and anesthesia influence rates of deep vein thrombosis following total hip arthroplasty.

Adolescent↗

Intermittent pneumatic compression prophylaxis for proximal deep venous thrombosis after total hip replacement.

The efficacy of intermittent pneumatic compression in the prevention of proximal deep venous thrombosis was determined in a consecutive series of patients who had primary or revision total hip replacement. Two hundred and eighty-nine patients (242 primary and eighty revision hip replacements) who were at least forty years old were managed intraoperatively and postoperatively with intermittent pneumatic compression with use of thigh-high sequential compression sleeves and thigh-high elastic compression stockings as the only form of prophylaxis. Venous ultrasonography of the ipsilateral lower extremity was performed, at an average of five days postoperatively, to determine the presence of a thrombus in the femoral and popliteal veins. The prevalence of proximal deep venous thrombosis was 6 per cent (twenty of 322 procedures), and no patient had a clinically detected pulmonary embolism. The prevalence of a proximal thrombus was 4 per cent (ten of 233 procedures) when a regional anesthetic had been used and 11 per cent (ten of eighty-nine procedures) when a general anesthetic had been used; this difference was significant (p = 0.02). The prevalence of a proximal thrombus was 3 per cent (eight of 245 procedures) for patients who were less than seventy-five years old and 16 per cent (twelve of seventy-seven procedures) for patients who were seventy-five years old or more (p < 0.0001). No patient had a major bleeding complication. Twenty-nine other patients who had an additional risk factor for thrombosis, such as a history of deep venous thrombosis, were managed with intermittent pneumatic compression and low-dose warfarin. The prevalence of proximal deep venous thrombosis in this group of patients was 19 per cent (six of thirty-one procedures). Intraoperative and postoperative intermittent pneumatic compression, combined with the use of a regional anesthetic, was found to be highly effective in the prevention of proximal deep venous thrombosis after total hip replacement. Despite the limitations inherent in comparisons among series, it is noteworthy that the prevalence of proximal thrombosis in our series was similar to the reported prevalences in several large series of patients who had a total hip replacement and were managed with either low-dose warfarin or low-molecular-weight heparin. However, there was no risk of major postoperative bleeding in the current study.

Adult↗

Diagnosis of portal vein thrombosis in patients with hepatocellular carcinoma: efficacy of color Doppler sonography compared with angiography.

OBJECTIVE: The aim of this study was to determine the efficacy of color Doppler sonography in the diagnosis of portal vein thrombosis in patients with primary hepatocellular carcinoma. The findings on angiography were used as the gold standard for diagnosis. SUBJECTS AND METHODS: We compared the findings on color Doppler sonograms and hepatic angiograms in 18 patients with hepatocellular carcinoma and portal vein thrombosis and in 22 patients with hepatocellular carcinoma without portal vein thrombosis. In most patients, tumor-related thrombus of the portal vein was confirmed by autopsy or surgery. The sonographic criteria for diagnosing portal vein thrombosis included nonvisualization of portal vein flow, pulsatile flow in the thrombus, arterioportal shunts, and cavernous transformation of the portal vein. RESULTS: Nonvisualization of portal vein flow was the predominant color Doppler finding in all patients with portal vein thrombosis. Other flow abnormalities overlapped the finding of nonvisualization of portal vein flow in 10 of 18 patients with portal vein thrombosis. The sensitivity of color Doppler sonography was 100% for nonvisualization of portal vein flow, 89% for detection of pulsatile flow in the thrombus, 60% for detection of arterioportal shunts, and 100% for detection of cavernous transformation. Among these findings, pulsatile flow in the thrombus was diagnostic for pathologically proved neoplastic thrombi in the main portal vein; sensitivity and specificity were 89% and 100%, respectively, and accuracy was 96%. No portal vein that appeared normal on color Doppler sonograms was thrombosed on arteriograms. CONCLUSION: We conclude that color Doppler sonography is a useful means of imaging the vascular extension of a tumor-based thrombus and an accurate means of screening for portal vein thrombosis.

Angiography↗

1992 ARRS Executive Council Award. Detection of deep venous thrombosis: prospective comparison of MR imaging with contrast venography.

OBJECTIVE: Preliminary reports have described the use of MR imaging for the detection of deep venous thrombosis. However, no prospective study comparing MR imaging with contrast venography (the gold standard) has been reported. Accordingly, we performed a prospective, blinded study of the efficacy of MR imaging in 61 consecutive patients with clinically suspected deep venous thrombosis. In cases of disagreement, additional testing was performed to determine the diagnosis. SUBJECTS AND METHODS: From June 1991 to February 1992, 61 patients with clinically suspected deep venous thrombosis were examined with venography and MR imaging. The average time between studies was 3 hr. In 21 of the 61 patients, the final diagnosis was deep venous thrombosis. RESULTS: For detection of deep venous thrombosis in the pelvis, the sensitivity of MR imaging was 100% (9/9) with a 95% confidence interval of 72-100% and the specificity was 95% (52/55) with a 95% confidence interval of 85-99%. In the thigh, the sensitivity (16/16) and specificity (43/43) were both 100% with 95% confidence intervals of 83-100% and 93-100%, respectively. In the calf, the sensitivity was 87% (13/15) with a 95% confidence interval of 60-98% and the specificity was 97% (36/37) with a 95% confidence interval of 86-100%. CONCLUSION: We found no statistically significant difference between MR imaging and contrast venography in the detection of deep venous thrombosis. This result suggests that MR imaging is at least as sensitive and specific as contrast venography in the detection of deep venous thrombosis.

Female↗

Assessment of deep venous thrombosis in the lower limbs and pelvis: MR venography versus duplex Doppler sonography.

OBJECTIVE: This study was designed to compare the diagnostic value of MR venography and color Doppler sonography in the assessment of deep venous thrombosis. SUBJECTS AND METHODS: MR venograms and color Doppler examinations were obtained in 37 patients either with suspected deep venous thrombosis of the lower limbs or pelvis or with pulmonary embolism. Two-dimensional time-of-flight venography was used for all studies. MR and color Doppler data were collected prospectively and analyzed in a blinded manner. In a subset of 21 patients, MR venography and color Doppler sonography were prospectively compared with contrast-enhanced venography. RESULTS: When compared with contrast-enhanced venography, MR venography was 100% sensitive and 100% specific in the diagnosis of deep venous thrombosis above the knee. Color Doppler imaging depicted 13 of 15 cases of deep venous thrombosis and 5 of 6 venous examinations that had normal results, yielding a sensitivity and a specificity of 87% and 83%, respectively. The differences in sensitivity and specificity between MR venography and color Doppler sonography were not statistically significant. MR venography was 95% sensitive and 99% specific in detecting the extension of deep venous thrombosis, compared with the 46% sensitivity and 100% specificity of color Doppler sonography (differences in sensitivity, p < .01). MR images showed 29 collateral vessels, whereas only 21 were detected by contrast-enhanced venography (p < .04). CONCLUSION: MR venography seems to be more accurate than color Doppler sonography in detecting the extension of deep venous thrombosis. The positive diagnosis and extent of deep venous thrombosis can be easily detected and monitored by a noninvasive technique such as MR venography.

Adult↗

[Markers of thrombophilia in patients with retinal vein thrombosis].

BACKGROUND: Thrombophilia is an alteration of hemostasis that increases the risk to venous or arterial thrombosis. This condition may be the underlying cause of retinal vein thrombosis. AIM: To study the presence of thrombophilia in patients with retinal vein thrombosis. PATIENTS AND METHODS: Prospective study of 55 patients aged 22 to 86 years, with retinal vein thrombosis (central or branch). Antithrombin III, coagulant protein C, functional protein S, resistance to activated C protein, homocysteine, prothrombin G20210A gene, lupus anticoagulant and anticardiolipin antibodies were measured in all. RESULTS: Seventeen patients had thrombophilic markers (antiphospholipid syndrome in seven, hyperhomocysteinemia in six and resistance to protein C in three). Of these 17 patients, 53% had high blood pressure, 35% an abnormal serum lipid profile and 23% a personal history of thrombosis. The thrombosis was central in 12 (ischemic in four) and of a branch in five (ischemic in two). CONCLUSIONS: Thrombophilic markers must be assessed in patients with retinal vein thrombosis.

Activated Protein C Resistance↗

Anticardiolipin antibodies and the risk for ischemic stroke and venous thrombosis.

OBJECTIVE: To determine whether the presence of anticardiolipin antibodies is a risk factor for ischemic stroke and venous thrombosis in healthy adult men. DESIGN: A nested, case-control study in a prospective cohort. SETTING: A nationwide study of physicians. PARTICIPANTS: The study sample was drawn from the Physicians' Health Study, a randomized, double-blind, placebo-controlled trial of aspirin and beta-carotene in 22,071 male physicians. At entry, 68% of the participants submitted plasma samples that were subsequently frozen at -80 degrees C. During 60.2 months of follow-up, follow-up for nonfatal outcomes was 99.7% complete and ascertainment of fatal outcomes was 100% complete. We identified men with documented ischemic stroke, deep venous thrombosis of the leg, or pulmonary embolus and for whom a plasma sample was available. A control was matched by age, smoking history, and length of follow-up to each of the 100 patients with ischemic stroke and the 90 patients with deep venous thrombosis or pulmonary embolus. MEASUREMENTS: Plasma samples were assessed for IgG anticardiolipin antibodies by enzyme-linked immunosorbent assay. The mean anticardiolipin antibody titers of the case patients in the two diagnostic groups (ischemic stroke; venous thrombosis or pulmonary embolus) were compared with those of the control groups, and relative risks were calculated for patients in increasing percentile categories of anticardiolipin antibodies by conditional logistic regression. RESULTS: The anticardiolipin antibody titers were higher in case patients with deep venous thrombosis and pulmonary embolus than in their matched controls (P = 0.01). Persons with anticardiolipin antibody titers above the 95th percentile had a relative risk for developing deep venous thrombosis or pulmonary embolus of 5.3 (95% CI, 1.55 to 18.3; P = 0.01). The anticardiolipin antibody titers in case patients with ischemic stroke and controls were not significantly different (P > 0.2), and no clear trend of higher risks among those with elevated levels of anticardiolipin antibodies was observed. CONCLUSION: An anticardiolipin antibody level above the 95th percentile is an important risk factor for deep venous thrombosis or pulmonary embolus but not for ischemic stroke in healthy adult men.

Adult↗

The prevalence of deep venous thrombosis in patients with suspected paradoxical embolism.

OBJECTIVE: To determine the prevalence of venous thrombosis in patients with suspected paradoxical embolism. DESIGN: Observational study. PATIENTS: Two hundred sixty-four patients with clinically suspected embolic events underwent contrast transesophageal echocardiographic evaluation. Forty-nine patients (24 women, 25 men) had a patent foramen ovale. Forty-one patients had acute stroke, and 8 had acute limb ischemia. SETTING: Echocardiography laboratory of a community hospital. MEASUREMENTS: The presence of a patent foramen ovale was assessed by transesophageal contrast echocardiography. Forty-two patients had venographic evaluation of the lower-extremity venous system. RESULTS: Venous thrombosis was clinically suspected in 6 patients and documented in 24 of the 42 patients with patent foramen ovale who underwent venographic study (57%; 95% Cl, 41% to 72%). Venous thrombosis was confined to calf or popliteal veins in 15 cases. Fifteen of 17 patients who had venographic evaluation within 7 days of the index event had thrombosis compared with 9 of 25 patients who had later evaluations (P = 0.001). More patients with venous thrombosis than without venous thrombosis had a history of previous thromboembolism (13 of 24 compared with 1 of 18 [corrected], respectively; P = 0.001). CONCLUSION: When a patent foramen ovale is detected in a patient with embolism, occult leg vein thrombosis is frequently present.

Adult↗

Association of protein S deficiency with thrombosis in a kindred with increased levels of plasminogen activator inhibitor-1.

OBJECTIVE: A single kindred in North America with venous thrombosis was described as having defective fibrinolysis because of increased levels of plasminogen activator inhibitor-1 (PAI-1). Our study describes the discovery of protein S deficiency in this kindred and its association with venous thromboembolism. DESIGN: A family study. SETTING: Community. PARTICIPANTS: Twenty-eight adults (ages 21 to 71 years) from three generations of the kindred; seven had a history of venous thromboembolism. MEASUREMENTS: Plasma levels of total and free protein S antigen, as well as the activities of protein S, protein C, PAI-1, and antithrombin III. RESULTS: Six of 7 persons (86%) with a history of venous thromboembolism were deficient in total and free protein S; of 21 asymptomatic members, 9 were deficient in protein S (P = 0.08). When compared with these 9 asymptomatic family members, the 6 persons with protein S deficiency and a history of thrombosis tended to smoke (P = 0.01) and to have higher triglyceride levels (P = 0.001). Overall, the mean PAI-1 activity in the 7 persons who had thrombosis was 7.9 kAU/L (AU/mL) and was 9.3 kAU/L (AU/mL) in the 21 persons who did not have thrombosis (95% CI, -9.9 to 7.0). CONCLUSIONS: In this kindred, a deficiency of total and free or functional protein S is the cause of thrombosis. Measurement of PAI-1 activity was not useful in the evaluation of familial thrombosis. The utility of the routine measurement of PAI-1 activity in the evaluation of familial thrombosis has not been established.

Adolescent↗

Incidence of idiopathic deep venous thrombosis and secondary thromboembolism among ethnic groups in California.

BACKGROUND: Few studies have compared the incidence of deep venous thrombosis among ethnic groups. OBJECTIVE: To determine the incidence of deep venous thrombosis among ethnic groups. DESIGN: Analysis of the linked California Patient Discharge Data Set from 1991 to 1994. SETTING: California. PATIENTS: 17991 patients with idiopathic deep venous thrombosis (thrombosis without cancer or hospitalization within preceding 6 months) and 5573 patients with secondary thromboembolism (thromboembolism occurring within 3 months of seven different events). MEASUREMENTS: Ethnicity was determined by using race as documented in the data set. For idiopathic deep venous thrombosis, standardized age- and sex-adjusted incidences were calculated. For secondary thromboembolism, proportional hazards modeling was done. RESULTS: The annual incidence of idiopathic deep venous thrombosis per 1000000 persons older than 18 years of age was 230 for white persons, 293 for African Americans (rate ratio, 1.27 [95% CI, 1.07 to 1.51]), 139 for Hispanic persons (rate ratio, 0.60 [CI, 0.54 to 0.67]), and 60 for Asians and Pacific Islanders (rate ratio, 0.26 [CI, 0.22 to 0.30]). Compared with white persons, Asians and Pacific Islanders who developed secondary thromboembolism had a significantly lower relative risk (range, 0.22 to 0.61) for all seven conditions analyzed. CONCLUSIONS: Compared with white persons, Asians and Pacific Islanders have a very low incidence of idiopathic deep venous thrombosis and a very low relative risk for secondary venous thromboembolism.

Adult↗

Is embolic risk conditioned by location of deep venous thrombosis?

Sixty-eight patients clinically suspected of having (33), or at high risk for (35), deep venous thrombosis were studied with contrast venography, radiofibrinogen leg scanning, and impedance plethysmography as well as ventilation and perfusion lung scans. Thrombosis limited to the veins in the calf of the leg (unilateral or bilateral) was shown by venography in 12 patients. None of these patients had clinical symptoms or scan results indicating embolism. Fifteen patients had thrombosis involving proximal (thigh) as well as distal (calf) veins by venography. Eight had scan evidence of embolism, although only one was symptomatic. The combination of radiofibrinogen and impedance tests allows accurate detection of both the presence and location of deep venous thrombosis. The availability of sensitive and specific, noninvasive methods for detecting and localizing venous thrombosis, as well as the apparently low embolic risk of calf-only thrombosis may condition future approaches to prophylaxis and treatment of patients with or at high risk for deep venous thrombosis.

Humans↗

Portal system thrombosis: a complication of long-term residence at extreme altitude.

BACKGROUND: With induction of the Indian Army to heights over 5,000 meters above sea level, complications of long-term stay at extreme altitude have come to light. We describe our experience with patients developing portal system thrombosis. METHODS: Clinical data were collected over 2 years on patients hospitalized for thrombotic complications from high-altitude (HAA) and non-high altitude (non-HAA) areas. Site of thrombosis was confirmed by imaging or at surgery. Patients were investigated for conditions that predispose to venous thrombosis. RESULTS: Ten cases of portal system thrombosis were seen during the period; of these, 9 (mean age 28 [SD 3.9] years; all men) were from HAA. Mean duration of residence in HAA was 12.4 (4.9) months; two were smokers and six drank 7-22 g alcohol/day at least 5 times a week. The first symptom was abdominal pain; this was later complicated by gastrointestinal bleeding (n=5), fever (7), vomiting (7), and weight loss (5). Average time between onset of first symptom and reaching a tertiary-care hospital was 9.5 (4.7) days. Clinical examination showed ascites (8 cases), splenomegaly (7), and hepatomegaly (6). Mean hemoglobin level at admission was 15.8 (3.4) g/dL. Ascites was hemorrhagic; five cases also had large splenic hematoma. The site of thrombosis was splenic vein (7 cases), portal vein (6), and superior (4) and inferior (1) mesenteric vein. None of 5 patients investigated had any prothrombotic condition. Endoscopic/ sonographic evidence of development of collaterals appeared as early as 12-20 days after onset of symptoms. CONCLUSION: Residence in HAA for extended periods is a risk factor for development of portal system thrombosis. Persistent pain in abdomen in such individuals should raise the possibility of portal system thrombosis.

Adult↗