The incidence of deep venous thrombosis in patients with leg oedema after arterial reconstruction

Prospective screening for postoperative deep venous thrombosis in patients undergoing infrainguinal revascularization

PURPOSE

The incidence of deep venous thrombosis (DVT) in patients undergoing infrainguinal bypass graft procedures has not been well documented, and the need for routine prophylaxis remains controversial. The purpose of this study was to prospectively evaluate the risk of postoperative DVT complicating infrainguinal revascularization.

METHODS

Seventy-four patients undergoing infrainguinal bypass graft procedures during a 12-month period were prospectively screened for DVT. Bilateral lower extremity venous duplex scan imaging was performed preoperatively and within 1 week and 6 weeks, postoperatively. Routine DVT prophylaxis was not used, with anticoagulation reserved for specific indications.

RESULTS

Of the 74 patients screened, three patients (4.1%) had DVT identified on preoperative venous duplex scan imaging and were excluded from the study. Of the remaining 71 patients enrolled, only two patients (2.8%) had postoperative DVT. Postoperative DVT was ipsilateral to the bypass graft extremity in both patients, with involvement of the peroneal vein in one patient and the femoral vein in the other. Although routine prophylaxis was not used, 18 of these patients (25%) were anticoagulated for other indications, with DVT occurring in one patient (5.6%). Of the remaining 53 patients who did not receive postoperative anticoagulation, only one patient (1.8%) had DVT.

CONCLUSIONS

According to this prospective study, the risk of postoperative DVT in patients undergoing infrainguinal revascularization is low. Routine prophylaxis is not recommended, with postoperative anticoagulation reserved for specific indications.

Lower limb oedema following distal arterial bypass grafting

Lower-limb oedema following arterial bypass surgery for ischemia is a common sequela which can complicate wound healing or delay resumption of mobility. Its exact pathogenesis remains uncertain but many theories have been proposed. Lymphatic disruption during arterial exposure, and endothelial damage from atrophy of the media and oxygen-derived free radical release are currently favoured hypotheses. Infrequently, deep vein thrombosis follows surgery and may exacerbate the condition. Efforts aimed at reducing the oedema, such as the use of lymphatic preserving incisional approaches or the use of antioxidants, have given conflicting results. The use of compression hosiery and leg elevation appear to be the most effective measures in reducing postoperative lower limb oedema.

The concentration of high molecular weight compounds in interstitial tissue fluid: a study in patients with post-reconstructive leg oedema

OBJECTIVES

To study whether relative changes in the concentration of different proteins of the subcutaneous interstitial tissue fluid in patients with postreconstructive leg oedema could give information on the integrity of the capillary wall following vascular reconstruction.

MATERIALS

Sixteen patients developed ipsilateral leg oedema following femoropopliteal (n = 14) or femorotibial (n = 2) bypass surgery for intermittent claudication (n = 10) or critical lower limb ischaemia (n = 6) caused by obliterating atherosclerosis.

METHODS

The leg volume increase was measured according to the formula of a truncated cone. The blister suction method was used for sampling of subcutaneous interstitial tissue fluid. The concentration of albumin, transferrin, immunoglobulin G and alpha 2-macroglobulin of serum and blister fluid was measured with nephelometry.

RESULTS

Seven days postoperatively the mean leg volume increase was 32% (19.8%) in the operated leg compared to the contralateral side (p < 0.01). In the blister fluid each of the proteins had a significantly higher concentration in the operated leg compared to the control leg. This concentration difference was relatively larger for the proteins with the highest molecular weight, immunoglobulin G (p = 0.006) and alpha 2-macroglobulin (p = 0.002).

CONCLUSIONS

A relatively larger concentration difference of the bigger molecules in the subcutaneous interstitial tissue fluid in patients with post-reconstructive leg ocdema suggests increased capillary permeability to plasma proteins following vascular reconstruction.

Lymph drainage and the development of post-reconstructive leg oedema is not influenced by the type of inguinal incision. A prospective randomised study in patients undergoing femoropopliteal bypass surgery

OBJECTIVES

To see whether the type of groin incision influenced the degree of postoperative leg oedema and the occurrence of lymphatic damage.

DESIGN

Prospective randomised clinical study.

SETTING

University Department of Surgery.

MATERIALS

Twenty-four patients undergoing femoropopliteal bypass reconstruction with either a lateral groin incision (Group A, n = 12) or a direct incision over the femoral vessels (Group B, (n = 12).

CHIEF OUTCOME MEASURES

The leg volume increase was measured according to the formula of a truncated cone. Deep venous thrombosis was excluded by air plethysmography and colour-coded Duplex scanning. Lymphatic lesions were detected by lymphoscintigraphy using 99mTc labelled human serum albumin.

MAIN RESULTS

One week following vascular reconstruction the median leg volume increase was 24.5% in Group A vs. 23.3% in Group B (NS). Lymphoscintigraphy revealed obstruction of the lymphatics in five patients of Group A vs. three patients of Group B (NS). Neither the occurrence of lymph cysts nor extravasation of lymph differed between the two groups. In seven patients no lymphatic lesion was observed. Patients with interruption of the lymphatics (n = 8) had a higher leg volume increase compared to the remaining patients with no or minor lymphatic lesions, 31.2% vs. 19.6%, respectively (p < 0.05).

CONCLUSIONS

Leg oedema and the occurrence of lymphatic damage following femoropopliteal bypass surgery is not reduced by applying a lateral approach to the femoral artery in the groin. However, the higher leg volume increase in patients with lymphatic obstruction indicates that lymphatic damage could play a part in the leg oedema formation.

Does the limb swell after revascularisation by percutaneous transluminal angioplasty?

OBJECTIVE

To discover if limb swelling occurs after successful revascularisation by percutaneous transluminal angioplasty (PTA).

DESIGN

Prospective Study.

SETTING

Vascular Laboratory.

MATERIALS

Twenty-five patients with occlusive arterial disease of the lower limb revascularised by percutaneous transluminal angioplasty were studied.

CHIEF OUTCOME MEASURES

The ankle/brachial pressure index and foot volumes measured by water displacement plethysmography were measured before and after PTA.

MAIN RESULTS

The volume of the revascularised limb increased by 2% on the first day postangioplasty (p = 0.009) and 4% on the 7th day (p < 0.001) compared with the contralateral leg.

CONCLUSIONS

Leg swelling is a consequence of revascularisation of the ischaemic limb and occurs in the absence of damage to the lymphatic drainage of the limb.

A randomised controlled trial of a low-molecular-weight heparin (Enoxaparin) to prevent deep-vein thrombosis in patients undergoing vascular surgery

The incidence of postoperative deep vein thrombosis (PDVT) after aortic surgery and lower limb revascularisation has not been assessed by a large prospective study. In a prospective randomised trial the effect of a low-molecular-weight heparin fragment, Enoxaparin (ENX) 4200 anti factor Xa IU once daily was compared to that of unfractionated heparin (UFH) 7500 IU twice daily. Two hundred and thirty-three consecutive patients were classified into three groups, aortic or aortoiliac and aneurysmectomy (n = 75), aorto-femoral bypass for atherosclerotic disease (n = 71), and femoropopliteal or femorodistal bypass (n = 87). Patients were analysed for development of deep vein thrombosis by Duplex scanning and, if positive, by venography between the seventh and tenth postoperative day. PDVT was present in 10 patients in the ENX group and in four patients in the UFH group (8.2 and 3.6% respectively, NS). The incidence of PDVT was 8% after aortic or aortoiliac aneurysmectomy, 7% after aortofemoral revascularisation, and 3.4% after femoropopliteal or femorodistal bypass. The overall incidence of PDVT after aortic surgery was 7.5% (95% CI 5.4-9.7). There was no pulmonary embolism. Intra-operative blood loss and postoperative bleeding events did not differ significantly between the ENX and UFH groups. After 1 month follow-up, no clinical event or death could be related to PDVT or pulmonary embolism. In conclusion, in vascular surgery ENX is as safe and effective in the prevention of PDVT as is UFH.

The relevance of posturally induced microvascular constriction after revascularisation in patients with chronic leg ischaemia

In patients with severe chronic lower limb ischaemia, postural vasoconstriction is disturbed, resulting in enhanced skin microcirculatory perfusion on leg dependency. After vascular reconstructive surgery, postoperative oedema formation is frequently seen. In 31 patients with leg ischaemia undergoing revascularisation we investigated whether and, if so, for how long after surgery postural vasoconstriction would take to recover, and whether disturbed vasoconstriction correlates with the occurrence of postoperative oedema. Capillary microscopy and laser Doppler fluxmetry were used to assess nutritional and total skin perfusion, respectively. The measurements were performed before and up to 37 days after surgery. After revascularisation, the mean ankle blood pressure index rose from 40 to 82%. All patients, except those with persistently disturbed vasoconstriction showed improved microcirculatory parameters. Postural vasoconstriction was restored in 24 patients, occurring approximately on the eighth postoperative day. All patients who failed to recover vasoconstriction developed postoperative oedema. This study shows that the disturbance in postural vasoconstriction can be reversible, probably due to recovery of arteriolar smooth muscle tone, and that patients with persistently disturbed postural vasoconstriction, are prone to develop postoperative oedema.

The use of MRI in the investigation of leg oedema

Magnetic resonance imaging (MRI) was used in the diagnosis of various conditions giving rise to leg oedema, with special attention to the oedema after femoro-distal vascular reconstruction for obliterative atherosclerosis (n = 14). Patients with deep venous thrombosis (n = 6), chronic lymphoedema (n = 6) and closed muscular compartment syndrome (n = 2) were also investigated. Leg volume increase was measured according to the formula of a truncated cone. Interstitial fluid hydrostatic pressure (Pif) was recorded with the wick-in-needle technique. Spin echo series with 10 mm transverse slices were obtained with MRI. Following vascular reconstructions, leg volume increased 26% on the operated side. In the operated leg, no gradient in Pif was found between the posterior muscular compartment and the subcutaneous tissue. However, there was a significantly higher Pif in the subcutaneous tissue compared to the anterior muscular compartment (p less than 0.05). In the operated group, MRI revealed oedema around the entire circumference of the leg, mainly restricted to the subcutaneous tissue. In contrast, oedema of the leg muscles, particularly in the posterior compartments, was typical for patients having deep venous thrombosis. The group with chronic lymphoedema showed circumferential subcutaneous oedema alone or in combination with a fibrotic honeycomb pattern. Oedema of the affected muscular compartment was easily observed in patients who had a closed compartment syndrome. In conclusion, the use of MRI is promising in the investigation of conditions giving rise to leg oedema. It is likely that the formation of post-reconstructive oedema is taking place in the subcutaneous tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Local regulation of blood flow and the occurrence of edema after arterial reconstruction of the lower limbs

The relation between edema after arterial reconstruction of the lower limbs and various potential etiologic factors, including disturbances in local blood flow regulating mechanisms, was investigated in 22 patients with occlusive arterial disease. The occurrence of edema was unrelated to the severity of symptoms as well as to the perioperative changes in distal arterial blood pressure. Postreconstructive edema developed independently of postreconstructive hyperemia and of disturbances in the local vasoconstrictor response to increased venous pressure. The decisive factor for development of edema was the extensive dissection in the thigh and in the popliteal region required for femoropopliteal bypass surgery. Edema developed after nine of nine femoropopliteal bypass operations, and only after one of 12 reconstructions in the aorto-iliac or in the profound femoral segments (p = 0.001). It is concluded that the postreconstructive edema is a lymphedema due to surgical trauma, rather than the result of microvascular derangement.