C.  Patients’ risk for recurrence is determined by the amount of residual thrombus. If there is no residual thrombus on venous duplex, additional anticoagulation is unnecessary.

D.  Stop anticoagulation and start aspirin.

Question 11

What is your recommendation regarding a thrombophilia evaluation?

A.  It is not necessary to perform an expensive thrombophilia evaluation since this was a DVT of pregnancy.

B.  Defer the thrombophilia evaluation until after the patient discontinues anticoagulation. C.  Since this patient will be on indefinite anticoagulation, a thrombophilia evaluation is

not necessary.

D.  Perform tests not affected by anticoagulation and complete the evaluation after anticoagulation has been discontinued.

An abbreviated thrombophilia evaluation of: lupus anticoagulant, antiphospholipid/anticardiolipin antibody, factor V Leiden, prothrombin gene mutation, and homocysteine was negative. The remainder of the thrombophilia evaluation will be completed in 1–2 years, at which time it is anticipated that the patient’s Coumadin will be discontinued.

52.1  Commentary

In 2008, it was recognized by the ACCP guidelines on antithrombotic therapy for venous thromboembolism1 that iliofemoral deep venous thrombosis represents a condition with a uniquely high incidence of post-thrombotic morbidity.2–4

This patient’s presentation was clinically consistent with iliofemoral deep venous thrombosis associated with a pulmonary embolism. The adventitia of the femoral vein is innervated with sensory nerves; therefore, pain on palpation of the femoral vein as a result of its distension is a frequent physical finding. The femoral vein distends as a result of the associated venous hypertension and thrombosis, and there may be an associated inflammatory response.

Patients presenting during off hours to the emergency department who are at high clinical risk of a venous thromboembolic condition should be anticoagulated [Q1: C] until a definitive diagnosis is made.1A ventilation/perfusion (V/Q) lung scan is not performed in this patient because she is pregnant and the clinical probability of a pulmonary embolism is high. Likewise, a CT angiogram is not performed because of the excessive amount of radiation. The likelihood of the venous duplex demonstrating acute DVT is also high. This patient’s treatment will not be altered by the V/Q scan or CTA findings. There is appro­ priate reluctance to expose the pregnant patient to a radioisotope or the radiation of a CTA. Standard ascending phlebography is not necessary, since the clinical presentation and venous duplex will establish the diagnosis with a high degree of accuracy.

Once anticoagulation is established, it is not necessary and actually counterproductive to maintain the patient at bed rest.5 An echocardiogram is advisable in all patients who have the diagnosis of pulmonary embolism to evaluate its impact on right ventricular function; however, it is not necessary in this patient to perform an “off hours” echocardiogram since the patient can be adequately treated until the next business day.

This patient’s thrombus extends from the posterior tibial vein to the external iliac vein, as documented on venous duplex. The natural history of these patients is one of significant post-thrombotic morbidity. [Q2: B, C] Akesson and colleagues3 demonstrated that within 5 years of anticoagulation for iliofemoral deep venous thrombosis, 95% of patients had documented venous insufficiency, 15% had venous ulceration, and 15% suffered with venous claudication. Delis et al.4 studied in greater detail a similar but larger cohort of patients with iliofemoral deep venous thrombosis and performed exercise testing. They demonstrated that 40% developed symptoms of venous claudication. While pregnancy is an induced hypercoagulable state, delivery of the present patient’s child is not known to alter the natural history of the patient’s acute venous thrombosis. In order to reduce the high risk of post-thrombotic sequelae, a strategy of thrombus removal should be considered. Operative venous thrombectomy [Q3: E] is the best recommendation in light of the fact that the patient does not wish to face any risk of bleeding with thrombolytic therapy. Rheolytic thrombectomy is in its early stages, and to date has not been shown to be effective by itself in the absence of incorporating a plasminogen activator.6 Oral anticoagulation during pregnancy is not recommended. Although this patient is in her third trimester and warfarin embryotrophy is not a concern, the potential exaggerated coagulopathy of the fetus due to its immature liver and potential fetal bleeding complications during delivery as a result of passage through the birth canal make oral anticoagulation inadvisable. Heparin anticoagulation until delivery followed by oral anticoagulation is commonly offered to these patients; however, their post-thrombotic morbidity is high.

A decision was made to proceed with venous thrombectomy. Patients can be anticoagulated overnight and the operation performed the next business day. Venous thrombectomy does not need to be performed as an “emergency operation.” [Q4: B, D] In all patients in whom a venous thrombectomy is performed, it is important to know the proximal extent of thrombus, particularly whether there is thrombus in the inferior vena cava. Therefore, a contralateral iliocavagram is performed prior to the iliofemoral venous thrombectomy. As mentioned earlier, it is assumed that this patient has had a pulmonary embolism and the radiation exposure of a CT scan or a V/Q scan is unnecessary, since their results are unlikely to change this patient’s management. However, in the non-pregnant patient, a spiral CT scan of the head, chest, abdomen, and pelvis would be performed. The rationale for CT scanning is that approximately 50% of patients with proximal DVT will have an asymptomatic pulmonary embolism. Up to 25% of these patients will develop subsequent pulmonary symptoms.7 When the symptoms surface during anticoagulation, the symptoms are often misinterpreted as “failure” of anticoagulation, when in reality it is the natural evolution of the patient’s initially asymptomatic (undiagnosed) pulmonary embolism. The proximal extent of thrombus in the vena cava or iliac veins often can be identified, as well as screening for associated intra-abdominal, retroperitoneal, or pelvic pathology.

The patient was treated with anticoagulation overnight. Before going to the operating room a contralateral iliocavagram was performed. Information regarding the proximal

extent of thrombus is particularly important, since the details of thrombus extension may alter the procedure. Nonocclusive thrombus in the vena cava is concerning because of its potential for fragmentation and embolization. This author believes that most of these patients should be protected against potential embolization during the procedure. This can be accomplished either with a suprarenal vena caval filter, as was inserted in this patient, since it was presumed that she already had suffered a symptomatic pulmonary embolism. Alternatively, suprathrombus balloon occlusion during the caval thrombectomy can be performed. This patient also underwent a preoperative echocardiogram (which was normal) to evaluate the impact of her presumed pulmonary embolism on right ventricular function. Echocardiography should be performed in all patients with pulmonary embolism, since it is a predictor of chronic thromboembolic pulmonary hypertension, and patients who have rightsided abnormalities should be considered for thrombolytic therapy or mechanical thromboembolectomy. [Q5: D, E]

During the operative procedure, fluoroscopy is used to guide the placement of the balloon catheter so as not to dislodge the vena caval filter. Fluoroscopy is also used to assess the success of thrombectomy and to evaluate for underlying venous lesions and their correction (Fig. 52.3). Since the fetus is well developed by the third trimester, the risk to the fetus from modest X-ray exposure is low. Fetal monitoring is routinely performed throughout the procedure. The monitoring devices must be checked so as not to interfere with appropriate imaging of the venous system during the procedure. Shielding of the fetus would obscure the iliac veins and distal vena cava. [Q6: B, C] Previous descriptions of iliofemoral venous thrombectomy focus only on the iliofemoral venous system. An occluded infrainguinal venous system reduces venous return through the thrombectomized iliofemoral veins, and leaves substantial thrombus burden infrainguinally with its resultant post-thrombotic sequelae. Current techniques of infrainguinal venous thrombectomy allow the procedure to be performed successfully following a cut-down on the posterior tibial vein.8 [Q7: C] Therefore, contemporary venous thrombectomy should be viewed much the same as arterial thrombectomy, that is, removing as much thrombus from the venous circulation as is physically and pharmacologically possible, correcting any underlying lesion, and perform mechanical and pharmacological maneuvers to avoid recurrent thrombosis.

An iliac venous stenosis observed on completion phlebography is common. Correcting the underlying iliac vein stenosis is considered an important part of the procedure (Fig. 52.3). This is performed under fluoroscopic guidance and if recoil occurs, a selfexpanding stent is used to maintain unobstructed venous drainage from the iliac venous system into the vena cava. [Q8: C] Direct endophlebectomy of the iliac vein lesion and transposition above the right common iliac artery is a large operation, which has been replaced by the relatively simple balloon dilation and stenting.

Following successful thrombectomy of the infrainguinal and iliofemoral venous systems and correction of any underlying iliac vein stenosis, prevention of recurrent thrombosis is paramount. There are mechanical and pharmacologic measures which, if used, minimize recurrence. These include the construction of a femoral AV fistula using the end of the transected proximal saphenous vein (or a large side branch) anastomosed to the side of the proximal superficial femoral artery (Fig. 52.4). Frequently, the proximal saphenous vein must undergo a thrombectomy to restore its patency. The saphenous vein is not a

collateral pathway of venous drainage for patients with iliofemoral venous thrombosis. On occasion, it may be a collateral drainage pathway for patients with infrainguinal DVT. Since the infrainguinal venous system had patency restored, that is not an issue in this patient. The AV fistula is constructed to increase venous velocity in the iliofemoral veins; however, it should not increase venous pressure. Limiting the size of the anastomosis to approximately 4 mm usually accomplishes this goal. Pressure monitoring of the common femoral vein before and after flow is initiated through the AVF is important. If the venous pressure increases, one must suspect a proximal (iliac vein) stenosis or excessive flow through the AVF, either (or both) of which should be corrected.

An additional, effective adjunctive technique is the placement of a catheter into the posterior tibial vein, which is used to anticoagulate the patient with unfractionated heparin postoperatively. A pediatric feeding tube is inserted into the posterior tibial vein and brought out through a separate stab wound in the skin adjacent to the lower leg incision. This small catheter is used for postoperative anticoagulation with unfractionated heparin. Targeting a therapeutic PTT ensures a high concentration of heparin in the diseased vein, which should substantially reduce the risk of recurrence. In the author’s experience, when these adjunctive techniques have been used, no patient has experienced rethrombosis. [Q9: A, C, E]. Following delivery, women can be anticoagulated with Coumadin, even if they wish to breastfeed.9 Warfarin is not excreted in the breast milk. Among the options, oral anticoagulation for 6–12 months is the most appropriate. [Q10: B] While it is true that residual thrombus increases the risk of recurrent thrombosis,10 and it appears that she has little if any residual thrombus, it would be inappropriate to treat this patient with less than a full course of anticoagulation.

Since this patient had extensive venous thrombosis and a positive family history, an underlying thrombophilia is suspected and the author would extend the duration of anticoagulation to 1 year or more. In patients on extended or indefinite anticoagulation, repeat evaluation for risk versus benefit is performed at least every 6 months. A thrombophilia evaluation is appropriate in this patient. A complete thrombophilia evaluation cannot be performed while the patient is on anticoagulation, since antithrombin III, proteins C and S, and factor VIII will be affected. However, lupus anticoagulant, antiphospholipid antibody, factor V Leiden, prothrombin gene mutation, and homocysteine levels can be obtained during anticoagulation and, if positive, may play a role in the subsequent management of this patient. [Q11: D]

References

 1. Kearon C, Kahn SR, Agnelli G, Goldhaber SZ, Raskob G, Comerota AJ. Antithrombotic therapy for venous thromboembolic disease: ACCP evidence-based clinical practice guidelines (8th ed). Chest. 2008;133(6):454S-545S.

 2. O’Donnell TF Jr, Browse NL, Burnand KG, Thomas ML. The socioeconomic effects of an iliofemoral venous thrombosis. J Surg Res. 1977;22:483-488.

 3. Akesson H, Brudin L, Dahlstrom JA, Eklof B, Ohlin P, Plate G. Venous function assessed during a 5 year period after acute ilio-femoral venous thrombosis treated with anticoagulation. Eur J Vasc Surg. 1990;4:43-48.

 4. Delis KT, Bountouroglou D, Mansfield AO. Venous claudication in iliofemoral thrombosis: long-term effects on venous hemodynamics, clinical status, and quality of life. Ann Surg. 2004;239:118-126.

 5. Partsch H, Kaulich M, Mayer W. Immediate mobilisation in acute vein thrombosis reduces postthrombotic syndrome. Int Angiol. 2004;23:206-212.

 6. Kasirajan K, Gray B, Ouriel K. Percutaneous AngioJet thrombectomy in the management of extensive deep venous thrombosis. J Vasc Interv Radiol. 2001;12:179-185.

 7. Monreal M, Rey-Joly BC, Ruiz MJ, Salvador TR, Lafoz NE, Viver ME. Asymptomatic pulmonary embolism in patients with deep vein thrombosis. Is it useful to take a lung scan to rule out this condition? J Cardiovasc Surg (Torino). 1989;30:104-107.

 8. Comerota AJ, Gale SS. Technique of contemporary iliofemoral and infrainguinal venous thrombectomy. J Vasc Surg. 2006;43(1):185-191.

 9. Bates SM, Greer IA, Pabinger I, Sofaer S, Hirsh J. Venous thromboembolism thrombophilia, antithrombotic therapy, and pregnancy: ACCP evidence-based clinical practice guidelines (8th ed). Chest. 2008;133(6):844S-886S.

10.Prandoni P. Risk factors of recurrent venous thromboembolism: the role of residual vein thrombosis. Pathophysiol Haemost Thromb. 2003;33:351-353.

Part XIII

Lymphodema