Deepveinthrombosis深静脉血栓.ppt

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1、What Is Deep Vein Thrombosis?pThe earliest case of DVT was described around 600-900 BC. pAt some point, the increased incidence of DVT in women after childbirth was noticed, and in the late 1700s, a public health recommendation was issued to encourage women to breast feed as a means to prevent this

2、phenomenon; the DVT was called milk leg, as it was thought to result from milk building up in the leg.What Is Deep Vein Thrombosis?pDeep vein thrombosis, or DVT, is a blood clot that forms in a vein deep in the body. Blood clots occur when blood thickens and clumps together.What Is Deep Vein Thrombo

3、sis?pA blood clot in a deep vein can break off and travel through the blood. The embolus could travel to an artery in the lungs and block blood flow. This condition is called pulmonary embolism, or PE.EpidemiologyDeep vein thrombosis* Diagnoses of DVT and PE are not mutually exclusive; an estimated

4、78,511 patients received diagnoses of both DVT and PE. VTE estimates include patients with diagnoses of either DVT or PE.EpidemiologyDeep vein thrombosisAccording to the most recent ACCP guidelines, VTE remains the second most common cause of protracted hospital stay and the third most common cause

5、of excess mortality among 7 million patients discharged from 944 acute care hospitals in the US.CausespGerman pathologist Rudolf Virchow postulated the interplay of three processes resulting in venous thrombosis, now known asVirchowstriad:Deep vein thrombosisIn keeping with Virchows concept, alterat

6、ions of the coagulation system that induce a hypercoagulable state also confer an increased risk of DVT. CausespGerman pathologist Rudolf Virchow postulated the interplay of three processes resulting in venous thrombosis, now known asVirchowstriad:Deep vein thrombosisCausesThe blood flow pattern in

7、the valves can cause hypoxemia, which is worsened by venous stasis, activates pathways - ones that include hypoxia-inducible factor-1and early-growth-response protein 1. Hypoxia-inducible factor-1 and early-growth-response protein 1 contribute to monocyte association with endothelial proteins, such

8、as P-selectin, prompting monocytes to release tissue factor-filled microvesicles, which presumably begin clotting after binding to the endothelial surface.9Deep vein thrombosisCausespIndependent Risk Factors for DVT Age is an independent risk factor for thrombotic disease. The majority of venous thr

9、ombi occur in either the superficial or deep veins of the leg. A DVT is stationary clotting blood adhered to the deep vein of the pelvis or an extremity and usually occurs in the calf or thigh. VTE denotes an obstruction arising from the formation of a clot in the venous circulation carried by the b

10、lood from the site of origin to plug another vessel.Deep vein thrombosisCausespIndependent Risk Factors for DVTDeep vein thrombosisSigns and symptomspCommon signs and symptoms of DVT include： Pain Swelling Warmth Redness or discoloration Distention of surface veinsDeep vein thrombosisSigns and sympt

11、omspCommon signs and symptoms of DVT include： Pain Swelling Warmth Redness or discoloration Distention of surface veinsDeep vein thrombosisSigns and symptomspIn most suspected cases, DVT is ruled out after evaluation, and symptoms are more often due to other causes, such as cellulitis, Bakers cyst,

12、musculoskeletal injury, or lymph edema.pOther differential diagnoses include hematoma, tumors, venous or arterial aneurysms, and connective tissue disorders.Deep vein thrombosisDiagnosispProbability:In those with suspected DVT, a clinical assessment of probability can be useful to determine which te

13、sts to perform. The most studied clinical prediction rule is the Wellsscore.Deep vein thrombosisDiagnosisDeep vein thrombosisDiagnosispPhysicalExam:symptoms Half of those with the condition HAVENOSYMPTOMS. Signs and symptoms alone are not sufficiently sensitive or specific to make a diagnosis, but w

14、hen considered in conjunction with known risk factors can help determine the likelihood of DVT.Deep vein thrombosisDiagnosispDVT diagnosis requires the use of imaging devices such as ultrasound. Clinical assessments, which predict DVT likelihood, can help determine if a D-dimer test is useful. pIn t

15、hose not highly likely to have DVT, anormalD-dimerresultcanruleoutadiagnosis.Deep vein thrombosisDiagnosispD-dimer:A fibrin degradation product, and an elevated level can result from plasmin dissolving a clot, or other conditions.Deep vein thrombosisDiagnosis For those with a low or moderate probabi

16、lity of DVT, a D-dimer level might be obtained, which excludes a diagnosis if results are normal. An elevated level requires further investigation with diagnostic imaging to confirm or exclude the diagnosis.Deep vein thrombosisDiagnosis For a suspected first leg DVT in a low-probability situation, t

17、he American College of Chest Physicians (ACCP) recommends testing either D-dimer levels with moderate or high sensitivity or compression ultrasound of the proximal veins. Deep vein thrombosisDiagnosispImaging:Imaging tests of the veins are used in the diagnosis of DVT. Ultrasound, CTscanvenography,

18、MRIvenography, or MRIofthethrombusare also possibilities.Deep vein thrombosisDiagnosispUltrasound:a sensitive and specific tool for the assessment of patients presenting with symptoms suggestive of lower extremity DVT.Deep vein thrombosisDiagnosispDoplerUltrasoundDeep vein thrombosisDiagnosispContra

19、stVenography:The gold standard methods to reveal whether the venous supply has been obstructed. Deep vein thrombosis(a)directmanualcontrastinjectionintotheguidingcatheter(direct venography technique, DVT)and(b)occlusionofcoronarysinusbyaSwan-Ganzcatheter.DiagnosispContrastVenography:The gold standar

20、d methods to reveal whether the venous supply has been obstructed. Unilateral above knee DVT in a patient with a recent right hemisphere cerebral infarction.A 19-year-old man with May-Thurner syndrome with swelling of the left lower extremity.Phlebography in a patient with deep venous thrombosis.Dee

21、p vein thrombosisDiagnosispThe AAFP and the ACP have published a clinical practice guideline that summarizes current approaches for the diagnosis of DVT Clinical prediction rules should be used to estimate the pretest probability of DVT . In selected patients with a low pretest probability of DVT or

22、 PE, a negative high-sensitivity D-dimer test indicates a low likelihood of VTE. Ultrasound is recommended for patients with intermediate to high pretest probability of DVT in the legs. Patients with intermediate or high pretest probability of PE require additional diagnostic imaging studies.Deep ve

23、in thrombosisDiagnosisDeep vein thrombosisTreatmentpThe main goals of treatment for DVT include prevention of PE, VTE and recurrent thrombosis. pOnce VTE is suspected, anticoagulation should be started immediately unless there is a contraindication. Deep vein thrombosisTreatmentpMedicalManagement:An

24、ticoagulation UnfractionatedHeparin Weight-based dosing of UFH (80 U/kg bolus followed by 18 U/kg/hr IV infusion) has been shown to achieve a therapeutic activated partial thromboplastin time (aPTT) more rapidly than fixed-dose regimens. Deep vein thrombosisTreatmentpMedicalManagement:Anticoagulatio

25、n Low-Molecular-Weight-Heparin LMWH is administered as a weight-based subcutaneous injection. In the current ACCP guidelines, LMWH is recommended over UFH for the initial treatment of DVT or PE. Enoxaparin, the most commonly used agent in the US, is given either as a once-daily injection (1.5 mg/kg/

26、day) or twice daily (1 mg/kg every 12 hr). Deep vein thrombosisTreatmentpMedicalManagement:Anticoagulation FactorXaInhibitors Fondaparinux is an indirect factor Xa inhibitor that can be used as VTE prophylaxis in medical patients, those undergoing orthopedic procedures (total hip and knee arthroplas

27、ty), and those undergoing abdominal surgery. Deep vein thrombosisTreatmentpMedicalManagement:Anticoagulation Warfarin Warfarin remains the mainstay of therapy for long-term treatment of VTE. It may be initiated once anticoagulation with UFH, LWMH, or fondaparinux has been started (and which should b

28、e continued as overlap treatment for a minimum of 5 days and until the international normalized ratio INR is at least 2.0 for 24 hours).Deep vein thrombosisTreatmentpMedicalManagement:Anticoagulation NewOralAnticoagulants Dabigatran：direct thrombin inhibitor Rivaroxaban：factor Xa inhibitorDeep vein

29、thrombosisTreatmentpMedicalManagement:Anticoagulation ThrombolyticTherapy Thrombolytic therapy for DVT may be beneficial in selected patients, and although it can be administered systemically. Thrombolytic therapy for acute PE remains controversial because there has been no clearly established short

30、-term mortality benefit. Deep vein thrombosisTreatmentpMedicalManagement:Surgical/Mechanicalintervention PulmonaryEmbolectomy According to ACCP guidelines, pulmonary embolectomy for the initial treatment of PE is reserved for patients with massive PE (documented angiographically if possible), shock

31、despite heparin and resuscitation efforts, and failure of thrombolytic therapy or a contraindication to itsDeep vein thrombosisTreatmentpMedicalManagement:Surgical/Mechanicalintervention VenaCavalInterruption Current guidelines recommend against the routine use of inferior vena cava (IVC) filters fo

32、r the treatment of VTE. Indications for the placement of IVC filters include a contraindication to anticoagulation, complications of anticoagulation, recurrent thromboembolism despite adequate anticoagulant therapy, and patients undergoing pulmonary embolectomy.Deep vein thrombosisTreatmentpThe dura

33、tion of treatment following the diagnosis of DVT depends on the risk of recurrence, including idiopathic DVT or PE, certain underlying hypercoagulable states such as the antiphospholipid syndrome, and underlying malignancy. Deep vein thrombosisTreatmentpAlthough the risk of recurrence decreases with

34、 longer durations of anticoagulation, clinicians must weigh the risk of bleeding against the risk of new thrombosis.Deep vein thrombosisPreventionpApproximately two-thirds of all DVT events result from hospitalization, yet only one third of all hospitalized patients at risk receive adequate prophyla

35、xis.pPE is the most common preventable cause of hospital death in the US. Without prophylaxis, the incidence of hospital-acquired DVT is 10% to 20% among medical patients and higher (15% to 40%) among surgical patients.Deep vein thrombosisPreventionpApproximately two-thirds of all DVT events result

36、from hospitalization, yet only one third of all hospitalized patients at risk receive adequate prophylaxis.pPE is the most common preventable cause of hospital death in the US. Without prophylaxis, the incidence of hospital-acquired DVT is 10% to 20% among medical patients and higher (15% to 40%) am

37、ong surgical patients.Deep vein thrombosisPreventionpLong-term complications include recurrent VTE, CTPH, and the PTS.pThe recurrence rate for idiopathic VTE approaches 30% after 10 years, the incidence of CTPH is 4% at 2 years, and the rate of PTS is 30% at 8 years.pD dimer is an excellent test to

38、exclude VTE.pDuplex ultrasonography is the noninvasive test of choice for the diagnosis of DVT.Deep vein thrombosisPreventionpComputed tomographic pulmonary angiography has replaced the ventilation perfusion scan for diagnosing PE.pRisk stratification is the key to management of patients with VTE.pI

39、ndefinite anticoagulation should be considered for patients with an idiopathic or unprovoked VTE.pAppropriate prophylaxis remains underused.Deep vein thrombosisReferencesDeep vein thrombosispPubmed: http:/www.ncbi.nlm.nih.gov/pubmed/ pWikipedia: http:/en.wikipedia.org/wiki/Main_PagepGoogle: http:/.hk/pThe Cleveland Clinic: http:/ Thank You!Xiang Yu C