Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “THROMBOSIS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 775 records · Page 43Linked to original sources
PubMedDate not supplied

Thrombolytic effects of intracoronary streptokinase on canine coronary artery thrombosis.

The thrombolytic and hemodynamic properties of intracoronary streptokinase (SK) application were studied in an in-vivo canine model with left circumflex coronary artery thrombosis, initiated by electrical stimulation (150 microA, DC for 6 h) of the artery's intima via an implanted silver wire. In pentobarbital-anesthetized, open-chest dogs acute myocardial ischemia was determined by a dehydrogenase-dependent staining of the coronary artery perfusion area. Thrombus weight was determined post-mortem. Saline-treated control animals developed coronary thrombosis after 3.1 +/- 0.4 h of stimulation. Thrombus weight was 64 +/- 3.1 mg. Acute infarct volume was 32 +/- 3.1% of total left ventricle, and 53 +/- 6.2% of the coronary artery risk region for infarction. At occlusive thrombosis, blood pressure, ventricular pressure and the LV dP/dtmax fell significantly, whereas heart rate and the end-diastolic filling pressure increased. Severe ST-segment elevation and loss of R wave voltage indicated myocardial ischemia. At 20 min into thrombotic vessel occlusion, 2,000 IU/min SK were infused by way of a Sones-catheter advanced to the thrombus. Coronary thrombosis consistently lysed after 12 +/- 0.7 min of SK infusion, and coronary blood flow as well as hemodynamics were restored. Only minor acute infarction was found indicating viability of ischemic jeopardized myocardium. In another group, the continuous SK-infusion (20 IU/kg/min) concomitant with electrical vessel stimulation prevented coronary thrombosis and acute ischemia, and no significant hemodynamic alterations were noted. These results indicate that intracoronary SK-infusion can lyse acute thrombosis as sequel of electrical stimulation. This prevents development of acute myocardial infarction. Continuous SK-infusion can completely prevent coronary thrombosis in response to intimal injury.

Animals↗
PubMed1997

PIA1/A2 polymorphism of platelet glycoprotein IIIa and risks of myocardial infarction, stroke, and venous thrombosis.

BACKGROUND: The gene encoding the platelet glycoprotein IIIa receptor (GPIIIa), shows polymorphism (PIA1/A2). In a previous study, men with acute coronary ischaemia were more likely than controls to carry the PIA2 allele. This receptor has an important role in acute thrombus formation; these findings therefore raise the possibility of inherited platelet risk factors for both arterial and venous thrombosis. We investigated whether the PIA2 allele is associated with myocardial infarction, stroke, and venous thrombosis in a large prospective cohort of men in the USA. METHODS: 14916 initially healthy men participating in the Physicians Health Study provided baseline blood specimens for DNA analysis and were followed prospectively for a mean of 8.6 years. 374 men had a first myocardial infarction, 209 stroke, and 121 venous thrombosis during follow-up (704 cases). Distribution of the PIA1/A2 polymorphism was investigated by a PCR based on restriction-fragment length polymorphism in these men and in a sample of 704 matched study participants who remained free of thrombosis during follow-up (controls). FINDINGS: The frequency of the PIA2 allele was similar to the control frequency (14.8%) among men who had myocardial infarction (13.5%, p = 0.4), stroke (13.4%, p = 0.5), or venous thrombosis (14.5%, p = 0.9). The relative risk of any vascular event among men homozygous or heterozygous for PIA2 compared with men homozygous for PIA1 was 0.96 (95% CI 0.8-1.2). We found no evidence of association between the PIA2 allele and myocardial infarction (relative risk 0.93 [95 0.7-1.2]), stroke (0.93 [0.7-1.3]), or venous thrombosis (1.07 [0.7-1.6]). There was no evidence of association in subgroup analyses by age, smoking status, and presence of family history of premature coronary disease, hypercholesterolaemia, hypertension, or diabetes. Aspirin use had no effect on these findings. INTERPRETATION: In a large cohort of apparently healthy men, carriage of the GPIIIa PIA2 allele was not associated with any increase in subsequent risk of myocardial infarction, stroke, or venous thrombosis.

Adult↗
PubMed1998

Duplex ultrasound in the hemodynamic evaluation of the late sequelae of deep venous thrombosis.

PURPOSE: The use of duplex ultrasound scanning to evaluate the hemodynamic outcome of deep venous thrombosis 7 to 13 years after the original diagnosis. METHODS: Duplex ultrasound was used to re-examine 1212 segments of vein from 72 patients (49 men, 23 women) with deep venous thrombosis previously diagnosed by means of phlebography to detect reflux and obstruction and evaluate flow; 611 segments were initially thrombosed and 601 segments were open. To define reflux, reversed flow in 31 healthy persons was measured. RESULTS: In a review of all veins of the 72 patients, 8 patients (11%) had completely normal duplex results in all veins, 33 (46%) had reflux, 6 (8%) had at least one noncompressible vein segment, and 25 (35%) had a combination of both. In the proximal vein segments without initial thrombosis a higher percentage was normal (73%) than in segments with initial thrombosis (46%). There was a significantly higher frequency of reflux (46%, p = 0.05) and noncompressibility (12%, p < 0.01) in initially thrombosed proximal vein segments than in vein segments without initial thrombosis (reflux 25%, noncompressibility 3%). Distal to the knee 125 (17%) of 720 vein segments were not traceable. Significantly more initially thrombosed vein segments were not traceable (p < 0.01). In distal vein segments there was no significant difference in reflux (7% versus 5%) and noncompressibility (10% versus 5%) between vein segments with and without initial thrombosis. Flow was present in 99% of the 611 previously thrombosed proximal and distal segments. CONCLUSIONS: Most patients with deep venous thrombosis still had venous abnormalities 7 to 13 years after the initial diagnosis. The most common abnormality was reflux. Significantly more abnormalities were found in initially thrombosed segments. The abnormalities were found in the proximal vein segments and in the distal vein segments, although less frequently in the latter.

Adult↗
PubMed2002

Individual risk assessment of thrombosis in pregnancy.

BACKGROUND: Thromboembolic complications during pregnancy are major contributors to maternal death, but there is no reliable way to estimate the absolute risk of thrombosis before the occurrence of a thromboembolic complication. OBJECTIVE: To create a model for individual estimation of thrombosis risk during pregnancy and to determine the distribution of risk estimates in a series of gravidae. METHOD AND PATIENTS: Estimates of absolute risk of pregnancy-related thromboembolism were calculated by multiplying reported figures of thrombosis incidence by prevalence-adjusted odds ratios of the following variables: smoking, parity, preeclampsia, mode of delivery, age, overweight, activated protein C resistance (FV Leiden or FV:Q506), thrombosis heredity, and previous thrombosis. We present the risk distribution among a unselected prospectively gathered cohort of 2384 unselected gravidae who were interviewed and tested for activated protein C resistance in early pregnancy. RESULTS AND CONCLUSIONS: A model for individual estimation of the absolute risk of thrombosis is presented, which is provided to the readers as a free automatic Internet-based service (http://www.riskpreg.com). As compared with antepartum, more women at high risk can be identified in the postpartum period and we suggest that this might be of use in planning the prevention of thrombosis.

Adult↗
PubMed2002

Treatment and outcome of pancreatic venous graft thrombosis after kidney--pancreas transplantation.

BACKGROUND: Pancreas venous graft thrombosis after transplantation is the main non-immunological cause of graft failure and usually results in pancreatectomy. Duplex Doppler ultrasonography is the primary imaging technique for monitoring vascular patency after pancreas transplantation. This study reports the results of rescue treatments for pancreas graft thrombosis after simultaneous pancreas--kidney transplantation. METHODS: One hundred and ninety-six patients with insulin-dependent diabetes mellitus received a simultaneous pancreas--kidney transplantation. Venous graft thrombosis was diagnosed in 25 of these patients based on Doppler ultrasonographic findings. RESULTS: Total venous graft thrombosis was diagnosed in 20 symptomatic patients, of whom 14 required graft pancreatectomy. Surgical thrombectomy was attempted in six patients with preserved arterial supply and was successful in four. Partial venous graft thrombosis was diagnosed in five asymptomatic patients; one also had partial splenic artery thrombosis. Rescue graft procedures included systemic anticoagulation (one patient), arterial thrombolysis (one) and venous thrombolysis and/or mechanical venous thrombectomy (four episodes in three patients). Graft rescue was achieved in three patients treated by venous thrombolysis/thrombectomy. CONCLUSION: Doppler ultrasonography allows the appropriate selection of rescue treatment based on the findings of total or partial thrombosis.

Adult↗
PubMed1997

The factor VR506Q mutation causing APC resistance is highly prevalent amongst unselected outpatients with clinically suspected deep venous thrombosis.

OBJECTIVE: Resistance to activated protein C (APC resistance), caused by a single point mutation in the factor V gene (FV:R506Q), is a major risk factor for venous thrombosis. As the significance of this mutation among unselected outpatients with deep-vein thrombosis (DVT) is not established, we have studied its prevalence among consecutive outpatients attending the emergency room due to a clinically suspected DVT. DESIGN, SETTING AND SUBJECTS: The FV:R506Q mutation was determined in 223 consecutive Swedish outpatients with clinically suspected DVT, and in 288 healthy controls. Using phlebography, the patients were classified as DVT-positive or DVT-negative. MAIN OUTCOME MEASURE: The prevalence of FV:R506Q mutation. RESULTS: The prevalence of the FV:R506Q mutation was 28% (28/99) in the DVT-positive subgroup (relative risk: 3.1; 95% CI: 1.7-5.5), and 23% (28/124) in the DVT negative subgroup (relative risk: 2.0; 95% CI: 1.1-3.6), as compared to 11% (32/288) in the control group. In the DVT-positive subgroup, the FV:R506Q mutation was most common among younger patients with primary thrombosis (47%) and least common among older patients with secondary thrombosis (19%). The high prevalence of FV:R506Q mutation among DVT-negative patients was associated with a high frequency of previous venous thrombosis. Thus, 46% (13/28) of the DVT-negative FV:R506Q carriers had a history of thrombosis, compared with only 22% (21/96) of the DVT-negative patients lacking the mutation (P = 0.01). CONCLUSION: To sum up, the FV:R506Q mutation is present in more than a quarter of Swedish DVT-positive outpatients with clinically suspected DVT, indicating that APC-resistance is a major thrombotic risk factor contributing to the high incidence of venous thrombosis in Sweden.

Adult↗
PubMed1997

Risk of Venous Thrombosis in Carriers of a Common Mutation in the Homocysteine Regulatory Enzyme Methylenetetrahydrofolate Reductase.

Background: Elevated levels of homocysteine are an independent risk factor for venous thrombosis. A common mutation in methylenetetrahydrofolate reductase (MTHFR), an enzyme required for efficient homocysteine metabolism, creates a thermolabile (tl-) enzyme with reduced activity that may predispose to hyperhomocysteinemia. Methods and Results: To assess whether this common mutation is a risk factor venous thromboembolism, a polymerase chain reaction-based genotyping assay was used to compare the prevalence of this mutation in a group with thrombosis versus several control groups. Of the 331 thrombosis subjects, 47% were heterozygous and 11% homozygous for tl-MTHFR. In comparison, heterozygotes constituted 42-47% and homozygous 15-16% of each of three control groups (totaling 593 subjects). There was no significant difference in the tl-MTHFR homozygote frequency or allele frequency between the thrombosis and control study groups. Although the prevalence of the factor V R506Q (Leiden) mutation causing activated protein C resistance was significantly higher in the thrombosis (19%) than in the control groups (4-9%), the concomitant presence of tl-MTHFR with factor V R506Q did not contribute to any excess thrombotic risk. Conclusions: Although the tl-MTHFR mutation may predispose to hyperhomocysteinemia, a known risk factor for venous thrombosis, this common genotype is not a direct genetic risk factor for venous thrombosis, either alone or in combination with the factor V R506Q mutation.

Journal Article↗
PubMed1981

[Prevention of venous thrombosis in recent ischaemic cerebrovascular accident: double-blind study with heparin-dihydroergotamine (author's transl)].

In a randomised, double-blind study 5,000 IU heparin-dihydroergotamine mesylate (Dihydergot) or placebo were administered over 14 days to 107 patients with recent ischaemic cerebrovascular accident. The patients were studied daily for recent venous thrombosis in the legs by means of the 125I-fibrinogen test. Thirteen patients died before venous thrombosis had been demonstrated, 13 others were excluded by other causes. Of the 41 patients in the placebo group 23 developed venous thrombosis, but only 11 of the 40 drug-treated patients. Bilateral venous thrombosis occurred in six patients on the placebo and one patient on the drug. Univariate analysis indicated that heart failure, reduction of muscle tone, muscular power and level of consciousness favoured thrombosis. Multivariate analysis further indicated that both bed-rest of several days before start of the prophylactic treatment and extreme obesity favoured thrombosis. The relative thrombosis risk increased by a factor of 15.2 when prophylactic measures were omitted. Death rate in the treated group ws 17.4%, in the placebo group 28.0%. These results indicate that a prophylactic regimen of the type described is a practicable and effective measure after recent ischaemic cerebrovascular accident.

Aged↗
PubMed1989

Detection of deep-vein thrombosis by real-time B-mode ultrasonography.

In 220 consecutive outpatients with clinically suspected deep-vein thrombosis of the leg, we compared contrast venography with real-time B-mode ultrasonography, using the single criterion of vein compressibility with the ultrasound transducer probe. The common femoral and popliteal veins were evaluated for full compressibility (no thrombosis) and noncompressibility (thrombosis). Both veins were fully compressible in 142 of the 143 patients with normal venograms (specificity, 99 percent; 95 percent confidence interval, 97 to 100). All 66 patients with proximal-vein thrombosis had noncompressible femoral veins, popliteal veins, or both (sensitivity, 100 percent; 95 percent confidence interval, 95 to 100). For all patients (including 11 with calf-vein thrombi), sensitivity and specificity were 91 (95 percent confidence interval, 82 to 96) and 99 percent, respectively. The sensitivity for isolated calf-vein thrombosis was only 36 percent. The compression ultrasound test was repeated in a subset of 45 consecutive patients by a second examiner, unaware of the results of the first test, whose results agreed in all patients with those of the first examiner (kappa = 1). We conclude that ultrasonography with the single criterion of vein compressibility is a highly accurate, simple, objective, and reproducible noninvasive method for detecting proximal-vein thrombosis in outpatients with clinically suspected deep-venous thrombosis.

Femoral Vein↗
PubMed1993

A comparison of real-time compression ultrasonography with impedance plethysmography for the diagnosis of deep-vein thrombosis in symptomatic outpatients.

BACKGROUND: Impedance plethysmography performed serially over a one-week period has been shown to be an effective diagnostic strategy for patients with clinically suspected acute deep-vein thrombosis. Compression ultrasonography has a high sensitivity and specificity for the detection of proximal-vein thrombosis. The clinical value of repeated ultrasonography in the management of symptomatic deep-vein thrombosis is unknown. METHODS: We conducted a randomized trial in 985 consecutive outpatients with clinically suspected deep-vein thrombosis to compare the diagnostic value of serial impedance plethysmography (494 patients) and serial compression ultrasonography (491 patients). We compared the positive predictive values of both tests for the diagnosis of venous thrombosis, using contrast venography as a reference. The frequencies of venous thromboembolism during a six-month follow-up period were also compared in patients with repeatedly normal results in order to evaluate the safety of withholding anticoagulant therapy from such patients. RESULTS: The positive predictive value of an abnormal ultrasonogram was 94 percent (95 percent confidence interval, 87 to 98 percent), whereas the predictive value of impedance plethysmography was 83 percent (95 percent confidence interval, 75 to 90 percent) (P = 0.02). In patients with repeatedly normal results, the incidence of venous thromboembolism during the six-month follow-up period was 1.5 percent (95 percent confidence interval, 0.5 to 3.3 percent) for serial compression ultrasonography, as compared with 2.5 percent (95 percent confidence interval, 1.2 to 4.6 percent) for serial impedance plethysmography. CONCLUSIONS: In making the diagnosis of deep-vein thrombosis in symptomatic outpatients, serial compression ultrasonography is preferable to impedance plethysmography, in view of its superior performance in detecting venous thrombosis.

Adolescent↗
PubMed1996

Hyperhomocysteinemia as a risk factor for deep-vein thrombosis.

BACKGROUND: Previous studies have suggested that hyperhomocysteinemia may be a risk factor for venous thrombosis. To assess the risk of venous thrombosis associated with hyperhomocysteinemia, we studied plasma homocysteine levels in patients with a first episode of deep-vein thrombosis and in normal control subjects. METHODS: We measured plasma homocysteine levels in 269 patients with a first, objectively diagnosed episode of deep-vein thrombosis and in 269 healthy controls matched to the patients according to age and sex. Hyperhomocysteinemia was defined as a plasma homocysteine level above the 95th percentile in the control group (18.5 micromol per liter). RESULTS: Of the 269 patients, 28 (10 percent) had plasma homocysteine levels above the 95th percentile for the controls, as compared with 13 of the controls (matched odds ratio, 2.5; 95 percent confidence interval, 1.2 to 5.2). The association between elevated homocysteine levels and venous thrombosis was stronger among women than among men and increased with age. The exclusion of subjects with other established risk factors for thrombosis (e.g., a deficiency of protein C, protein S, or antithrombin; resistance to activated protein C; pregnancy or recent childbirth; or oral-contraceptive use) did not materially affect the risk estimates. CONCLUSIONS: High plasma homocysteine levels are a risk factor for deep-vein thrombosis in the general population.

Adolescent↗
PubMed2001

Identification of factors predictive of lower extremity vein graft thrombosis.

OBJECTIVE: The objective of this study was to assess the prognostic value of hemodynamic parameters measured with duplex ultrasound scan, together with other important graft and patient characteristics, in predicting lower extremity vein graft thrombosis. METHODS: A total of 165 lower extremity vein grafts were entered prospectively into a postoperative duplex ultrasound scan surveillance program with examinations performed at 1, 2, 3, 4, 6, 9, 12, 18, and 24 months, and annually thereafter. Duplex scan-derived blood flow velocity measurements were recorded at 1562 patient visits over 7 years. Graft patency was determined after each visit, and an analysis of factors predictive of vein graft thrombosis was performed with Poisson regression. RESULTS: Thirty-two episodes of first-time graft thrombosis occurred, 23 of which were permanent. One-, 3-, and 5-year secondary graft patency rates were 90%, 86%, and 79%, respectively. In multivariate analyses, duplex scan velocity measurements predictive of lower extremity graft thrombosis included the maximum velocity ratio (Vr) in association with a graft stenosis and the mean graft peak systolic velocity (MGV) within nonstenotic portions of the body of the graft. The incidence of graft thrombosis among grafts without inflow/outflow stenoses, with Vr less than 3.5, and with MGV 50 cm/s or more, was 2.9% per year. Incidence rates were considerably higher among grafts with a of Vr of 3.5 or more (incidence rate ratio = 7.0; 95% CI, 3.4-14.6) or an MGV less than 50 cm/s (incidence rate ratio = 6.5; 95% CI, 3.3-13.1). In grafts without identifiable inflow, outflow, or graft stenoses, there was no association between MGV and the risk of graft thrombosis. CONCLUSION: Duplex scan velocity measurements are valid predictors of impending graft thrombosis. A Vr of 3.5 or more and an MGV less than 50 cm/s are the best predictive measures. Repair of correctable graft lesions with a Vr of 3.5 or more, or inflow, outflow, or graft lesions associated with an MGV less than 50 cm/s are recommended. Grafts without detectable inflow, outflow, or graft stenoses, regardless of MGV, may be safely followed.

Adolescent↗
PubMed1994

Experimental reproduction of free flap errors: a new model of thrombosis.

Surgical errors in the length and orientation of a flap pedicle can result in kinks, twists, or tension on the pedicle vessels. When these errors occur together with the microvascular repairs associated with free flap transfer, thrombosis and flap failure may be the outcome. A model was designed to simulate these events. The rabbit central ear artery and vein were dissected and all other tissue connections were severed in a near-complete amputation. The artery was transected, shortened by 2 mm, and repaired standardly. The ear was then rotated 360 degrees, twisting the vein around the repaired artery. The ear cartilage was shortened by 6 mm, then sutured, and the skin was closed. In a series of 20 ears, 95% necrosed, 18 from arterial thrombosis and 1 from venous thrombosis. Several other groups were used in which aspects of the basic model were modified to determine the factors influencing failure. When the arterial anastomosis was not performed and the vascular pedicle was rotated with cartilage shortening, all ears survived; when the cartilage was not resected in this paradigm, leaving tension on the pedicle, 50% of the ears necrosed from venous thrombosis. In counterpoint, when the artery was repaired without twisting the pedicle, all ears survived, whether or not the cartilage was shortened. When the artery was repaired without shortening it and with rotation of the ear, 50% of the ears necrosed when the cartilage was shortened, 40% from venous thrombosis and 10% from arterial thrombosis; all ears necrosed (of venous thrombosis) when the cartilage was not shortened.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1997

Lower extremity deep vein thrombosis: a prospective, randomized, controlled trial in comatose or sedated patients undergoing femoral vein catheterization.

OBJECTIVES: To determine the rate of lower extremity deep vein thrombosis after the use of femoral catheters in intensive care unit (ICU) comatose or sedated adults. Results were then compared with results of patients undergoing superior vena cava catheterization. DESIGN: Prospective, randomized, controlled, unblinded study. SETTING: A mixed medical/surgical ICU in a university hospital. PATIENTS: Sixty-one comatose or sedated patients admitted to the ICU who underwent central venous catheterization. INTERVENTIONS: Patients were monitored for signs of thrombotic complications. On catheter removal, a lower-extremity bilateral phlebographic examination was performed in each patient. MEASUREMENTS AND MAIN RESULTS: After randomization, 31 patients underwent femoral vein catheterization and 30 patients underwent superior vena cava catheterization, either by axillary (21 patients) or internal jugular vein (10 patients) cannulation. Single lumen polyurethane catheters were inserted for a mean duration of 7.1 +/- 4.6 (SD) days in the femoral vein group and 9.9 +/- 5.5 days in the superior vena cava group (p = NS). No patient had clinical signs of leg venous thrombosis or pulmonary embolism during the study period. In each patient, lower extremity bilateral phlebography was performed at the time of catheter removal. Leg phlebographies were normal in 18 (60%) patients in the femoral vein group and 26 (84%) patients in the superior vena cava group. Fibrin sleeves which developed around the femoral catheters were seen in seven (23.3%) patients in the femoral vein group and in no patients in the superior vena cava cannulation group. Three patients had femoral vein thrombosis, two (6.6%) patients in the femoral vein group (two nonobstructive thromboses, adherent to the common femoral vein wall) and one (3.0%) patient in the superior vena cava group (nonobstructive thrombosis which developed in the superficial femoral vein) (p = NS). Lower deep extremities thrombosis developed in five (16.7%) patients in the femoral vein group and in five (16%) patients in the superior vena cava group (p = NS). CONCLUSIONS: Femoral vein catheterization with a polyurethane catheter is associated with a lower rate of extremity deep vein thrombosis which is similar to the rate observed after superior vena cannulation in comatose or sedated patients. Femoral vein thrombosis was observed at a rate of 6.6% after femoral vein cannulation and a rate of 3% after superior vena cava cannulation. Given the acceptable rate of this clinically important complication, femoral vein cannulation offers an attractive alternative to insertion via the vena cava in the critically ill.

APACHE↗
PubMed1998

Bedside testing (SimpliRED) in the diagnosis of deep vein thrombosis. Evaluation of 250 patients.

RATIONALE AND OBJECTIVES: The authors evaluate the sensitivity and specificity of a bedside test (SimpliRED) in the diagnosis of deep vein thrombosis compared with contrast phlebography. METHODS: Two hundred fifty patients, referred for phlebography, underwent bedside testing for detection of deep vein thrombosis. Contrast phlebography was performed immediately afterward. SimpliRED provides a clearly visible agglutination of the patient's red blood cells in the presence of elevated levels of cross-linked fibrin derivative (D-dimer), which is specific for fibrin breakdown. RESULTS: In 82 (32.8%) patients, deep vein thrombosis was confirmed venographically. An abnormal D-Dimer test was found in 79 of the 82 patients with thrombosis (sensitivity: 96.3%). The three patients who were diagnosed falsely as normal on agglutinin testing, had venograms which showed only an isolated calf thrombosis in small muscle veins (< 2 cm in diameter) not requiring treatment. One hundred of 168 patients without venographic thrombosis were diagnosed correctly by SimpliRED (specificity: 59.5%). The positive predictive value was 53.7%; the negative predictive value was 96.8%. CONCLUSIONS: All thrombotic disorders in the leg that required further treatment were identified correctly. SimpliRED is a very sensitive test with moderate specificity in the diagnosis of deep vein thrombosis. Therefore, further invasive testing is needed only in those patients in whom the D-dimer test is abnormal. A false-positive result of the bedside test may be nonspecific or due to elevated levels of fibrin split products, which can occur whenever the coagulation system has been activated by any of several conditions.

Adolescent↗
PubMed1989

Deep venous thrombosis and pulmonary emboli: etiology, medical treatment, and prophylaxis.

Risk factors for venous thrombosis include conditions leading to venous stasis, hypercoagulable states, and trauma to veins. The most important factor is venous stasis. Both extrinsic and intrinsic coagulation pathways are intimately involved in the thrombotic process. In recent years, the importance in thrombus formation of the endothelium, platelet products, the fibrinolytic system, and inhibitors of clotting mechanisms has been discovered. Deficiencies of proteins that normally protect against venous thrombosis have been found. Heparin therapy with subsequent warfarin therapy is still the primary treatment for deep venous thrombosis or pulmonary emboli. Fibrinolytic agents lyse pulmonary emboli but are not as effective in deep venous thrombosis. The incidence of serious bleeding complications has hampered the use of fibrinolytic agents except in emergency situations. Even the newer agents, which act more specifically on thrombi instead of on plasma factors, are associated with a similar incidence of hemorrhagic events. Dextrans are a suitable alternative for treatment of deep venous thrombosis when heparin cannot be used. In the prophylaxis of deep venous thrombosis, minidose heparin (5,000 U every 8 hours subcutaneously) is effective, safe, and convenient in most situations. Heparin-dihydroergotamine, dextran, or warfarin can also be used. Aspirin has been disappointing. In orthopaedic surgery, minidose heparin is not protective; large pulmonary emboli may be prevented by starting warfarin therapy at the time of surgery or by daily dextran infusions. Finally, recent studies have shown that lower doses of warfarin than previously recommended are protective against recurrent venous thrombosis and have a reduced risk of hemorrhagic complications.

Ancrod↗
PubMed1996

Timing of pedicle thrombosis and flap loss after free-tissue transfer.

A series of 990 consecutive free flaps was reviewed to determine how often pedicle thrombosis occurred, when it occurred, and if the timing of thrombosis detection had any relationship to the probability of flap salvage. The overall thrombosis rate was 5.1 percent, and the flap loss rate was 3.2 percent. The majority (80 percent) of thrombi occurred within the first 2 postoperative days. Only 5 thrombi (10 percent) were known to have occurred after the third postoperative day. No flaps that developed thrombosis after the third postoperative day were salvaged successfully. Had flap monitoring been discontinued after the first 3 postoperative days, our results in this series would have been unchanged. Thrombosis of the vein (54 percent) was more common than arterial thrombosis (20 percent) or thrombosis of both artery and vein (12 percent). Almost all purely arterial thrombi (90 percent) occurred before the end of the first postoperative day, whereas 41 percent of all venous thrombi occurred later. We conclude that arterial monitoring is most critical immediately after surgery. Beginning on the second postoperative day, venous monitoring becomes progressively more important to flap success. The cost-effectiveness of postoperative monitoring of free flaps is greatest during the first 2 days, after which it decreases significantly.

Graft Rejection↗
PubMed1976

Is streptokinase useful in the treatment of deep vein thrombosis?

Because of its fibrinolytic action, streptokinase is believed to reduce the severity of the postthrombotic syndrome in patients with deep vein thrombosis. A prospective and a retrospective study have been undertaken in an attempt to determine when this therapy is useful for patients with deep vein thrombosis. The prospective study included 15 patients with deep vein thrombosis: 5 were treated in the hospital with streptokinase and heparin and 5 only with heparin, 5 were treated at home with only phenprocoumon. All the patients received oral anticoagulant therapy for at least 6 months. Three to four months after the acute episode, phlebography and venous pressure measurements were carried out. Streptokinase appeared to give the best results but with more side-effects. In the retrospective study, 51 patients who had had deep vein thrombosis in 1969 were reexamined 31-47 months later. It was found that more than 50% of the patients with a thrombosis in the femoral and/or iliac vein developed a severe postthrombotic syndrome, in contrast to only 9% of those with a thrombosis in the popliteal vein or lower. It is recommended, on the basis of both the prospective and the retrospective study, that patients with a thrombosis in the femoral and/or iliac vein should be treated with either heparin or streptokinase during the early stage. It is probable that streptokinase will significantly decrease the frequency and severity of the postthrombotic syndrome in these patients in particular, although this has not yet been proven.

Adult↗