Resolution of Saphenous Vein Graft Stenosis with Exercise: A Case Report
Article Outline
Abstract
Graft failure remains a significant clinical problem following infra-inguinal vein bypass surgery, with failure rates of 30–50% at 5 years. We present a case of saphenous vein graft stenosis in a 41-year old man which resolved spontaneously over eighteen weeks, without active vascular intervention. We attribute the observed improvement in graft haemodynamics and symptomology to the dedicated exercise regimen undertaken by the patient: cycling, swimming and cross-training a combined total of 125
km weekly. This case underscores the importance of aerobic exercise following vein bypass grafting in the lower limb.
Keywords: Vein graft stenosis, Haemodynamics, Exercise
Introduction
Graft failure following infra-inguinal vein bypass grafting is a significant clinical problem, often requiring further surgical or endovascular intervention. We present a case of in-graft stenosis which resolved without active vascular intervention. We attribute this phenomenon to the strenuous exercise regimen undertaken by the patient and consider potential mechanisms.
Report
A 41-year old man, with a history of Christmas disease (haemophilia B; factor IX deficiency) underwent coil embolisation of a symptomatic left subclavian arteriovenous malformation (AVM). Embolisation was performed using a percutaneous approach via the right common femoral artery (CFA). Post-embolisation images demonstrated occlusion of the AVM. The CFA insertion site was closed with a Perclose® suture-mediated closure device.
One week post-embolisation, the patient presented to the vascular department complaining of right calf claudication. An arterial duplex (USS) demonstrated almost complete occlusion of the right CFA with proximal thrombus formation and ischaemic flow in the distal vessels (Fig. 1A). The cause of these changes was related to the approximation of both the anterior and posterior walls of the CFA by the Perclose® device (Fig. 1B).
Figure 1
Duplex USS (A) revealed almost complete occlusion of the CFA (short arrow) with proximal thrombus (long arrow) and ischaemic distal flows (inset). The resected specimen (B) revealed the anterior and posterior vessel walls to have been plicated by the suture line (long arrow) causing the severe stenosis.
The patient was immediately transferred to theatre where the approximated CFA segment was resected and continuity restored with a reversed interposition saphenous vein graft anastomosed end–end with continuous sutures. The patient made a good post-operative recovery and was symptom free at two weeks, with a patent graft on USS.
At six weeks the patient complained of right calf claudication on exertion. USS suggested significant in-graft stenosis with a four-fold increase in peak systolic velocity (PSV) across the proximal anastomosis and further flow disturbance distally (Fig. 2A). Diagnostic angiography demonstrated a proximal anastomotic shelf and a “kinked” distal anastomosis. There was, however, good run-off into the vessels distal to the vein graft (Fig. 3). Ankle-brachial pressure indices (ABPI) were normal at rest, dropping to 0.85 on exertion. In view of the clinical features, Christmas disease and the graft not being at-risk a decision was taken to “watch and wait.” The patient was encouraged to continue with his normal activities of daily living, including exercise.
Figure 2
Duplex USS at six weeks (A) suggested significant stenosis with four-fold increase in PSV across the proximal anastomosis (120–480
cm/s) and monophasic flows within the graft (inset). Repeat USS 3 months later (B) demonstrated patent graft without obvious stenosis, PSV increase across the graft was no longer significant (168–278cm/s); flows were multiphasic (inset).
Figure 3
CFA angiogram at seven weeks demonstrated an anastomotic shelf at the proximal graft anastomosis (short arrow) and a “kinked” distal anastomosis (long arrow) but good flow in the superficial femoral artery, profunda femoris and popliteal artery.
The patient returned to his regular exercise regimen of cycling 15km daily, swimming 800m and cross-training 6km three times a week. At re-scan three months later, graft haemodynamics were much improved, with multiphasic flow and the absence of significant PSV increase across the graft (Fig. 2B). Two years post-operatively the patient remains asymptomatic with a patent graft, multiphasic flow and the absence of at-risk features.
Discussion
Infra-inguinal bypass grafting with autologous saphenous vein is associated with a significant graft failure rate of 30–50% at five years.1 Graft failure occurring between one month and one year post-operatively is often attributed to neo-intimal hyperplasia (NIH)2 which appears to commence soon after graft implantation, reflected by a rapid fall in conduit compliance over the first three post-operative months.3
Clowes et al. reported that following insertion of a common femoral arteriovenous fistula (AVF) there was a reduction in vascular smooth muscle density and decreased neo-intimal thickness within an aorto-iliac polytetrafluroethylene graft in baboons. The subsequent ligation of the AVF caused a reversal of this process.4 This poignant finding, albeit experimental, suggests clearly that increased flow across a graft is beneficial and has an advantageous role in vascular remodelling. A similar pattern of reduced neo-intimal formation has been demonstrated in apolipoprotein-E knock-out mice subjected to a six-week exercise programme on a motorised treadmill when compared to a sedentary control group.5 Furthermore, in human studies, augmentation of graft flow using intermittent pneumatic compression (IPC) following infra-inguinal vein bypass grafting improved claudication distance, ABPI and quality of life scores.6, 7
We postulate that increased flow across the graft secondary to a dedicated exercise regimen was potentially responsible for the observed improvement in graft haemodynamics and symptomology. We suggest regression of the neo-intima in this high flow environment as a potential mechanism for this observation. It is also plausible that the findings could have been attributed to thrombus formation. The presence of thrombus, however, would have been detected at the six-week scan and no such finding was present on duplex USS. Nevertheless, if thrombus was the cause for the observed changes in PSV, exercise may still have had a beneficial effect.
We recognise that the potential graft remodelling observed in this young, fit patient may not be directly transferable to older vasculopaths common in our practice. Furthermore, the atypical location of the vein interposition may have provided a more favourable haemodynamic environment than an infra-inguinal vein bypass graft. It is, however, clear that increased flow through a bypass graft is favourable regardless of the overall circumstances.
In summary we present a case of resolution of at-risk features in an interposition vein graft. To our knowledge this is the first documented example of exercise mediated graft “salvage” in a human subject. This case underscores the importance of aerobic exercise in patients following vein bypass grafting. Although intensive exercise regimens are not always realistic in the cohort of patients we treat, it is still a goal that maybe achieved through alternative methods of flow enhancement.
Conflict of Interest/Funding
None.
References
- . Lower extremity graft failure: a translational approach. Vasc Med. 2008;13:63–74
- . Vein compliance: a preoperative indicator of vein morphology and of veins at risk of vascular graft stenosis. Br J Surg. 1992;79:1019–1021
- . Compliance changes in in-situ femoropopliteal bypass vein grafts. Br J Surg. 1986;73:196–199
- . Increased blood flow inhibits neointimal hyperplasia in endothelialized vascular grafts. Circ Res. 1991;69:1557–1565
- . Exercise training reduces neointimal growth and stabilizes vascular lesions developing after injury in apolipoprotein e-deficient mice. Circulation. 2004;109:386–392
- . Haemodynamic effect of intermittent pneumatic compression of the leg after infrainguinal bypass grafting. Br J Surg. 2004;91:429–434
- . Effect of intermittent pneumatic compression of foot and calf on walking distance, haemodynamics and quality of life in patients with arterial claudication. Ann Surg. 2005;241:431–441
PII: S1533-3167(09)00020-X
doi:10.1016/j.ejvsextra.2009.04.006
© 2009 European Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.
Refers to article:
- Resolution of Saphenous Vein Graft Stenosis with Exercise: A Case Report , 19 June 2009
