Stenting as a bail-out option after failed percutaneous transluminal angioplasty in infrainguinal vein bypass grafts

Introduction

Occlusion of infrainguinal bypass grafts is a morbid and costly event and its prevention is worthwhile. ¹ Whereas graft surveillance of prosthetic grafts has not proven to be beneficial, ² surveillance is critical to the long-term outcomes of infrainguinal bypasses using vein grafts and has been shown to be cost-effective ¹ and beneficial to the long-term patency of the grafts. ³

Graft stenoses are often solitary and focal ⁴ and hence respond fairly well to percutaneous transluminal angioplasty,^5,6 though no consensus exists on its primary use.

The role of stents and stent-grafts in the percutaneous salvage of infrainguinal vein grafts is not yet defined and data are sparse. Jahnke et al. established its technical feasibility by using a monorail balloon-expandable stent device made of stainless steel. ⁷ Stent use has mainly been reported as a bail-out procedure when balloon angioplasty fails due to recoil, dissection or significant residual disease.^8,9 There are also numerous reports of stent grafts used to treat vessel rupture complicating angioplasty of vein grafts used in coronary circulation, lower limbs and haemodialysis access.^10–12

This study aims to evaluate the safety and efficacy of stents and stent grafts used as bail-out and adjuvant options in the salvage of failing infrainguinal vein grafts following balloon angioplasty. It also describes the indications necessitating their use.

Materials and methods

We reviewed a prospectively maintained database of the Queen Elizabeth Hospital Birmingham (Dendrite Clinical Systems, London, UK) over a 5-year period from 1 January 2008 to 31 December 2012. Patients were selected for percutaneous transluminal balloon angioplasty (PTA) on detection of significant infrainguinal vein graft stenosis (>70% stenosis: peak systolic velocity more than 300  cm/s and a velocity ratio across the stenosis of >3.5) by routine post-operative duplex surveillance of infrainguinal vein grafts at six weeks, three months, six months and every six months thereafter. Synthetic and composite part prosthetic and part venous grafts were excluded. The modality of treatment for these lesions was decided by the vascular surgical consultant based on morphologic characters of the lesion, patient co-morbidities, availability of conduit and patient preference. There was a preference for surgical revision for lesions which were diffuse and extending for more than one-third of the conduit length and those with suboptimal results or rapid restenosis after graft angioplasty provided other factors were favorable. All patients who had stents and stent-grafts inserted in infrainguinal vein bypass grafts were included. In the majority of these patients, these stents were not inserted primarily as a planned elective procedure, but only as bail-out options consequent to failure of angioplasty.

Results

From 1 January 2008 to 31 December 2012, 18 patients (4 females, 14 males) had stents and covered stents put in infrainguinal vein bypass grafts. Their mean age at the time of intervention was 73 years with a range of 56 to 86 years. There were 5 patients (28%) with diabetes mellitus, 13 (72%) with hypertension and 2 (11%) with elevate renal parameters (serum creatinine >150 mmol/L). Infragenicular bypass grafts formed the majority with 15 (83%). 8 of the 18 (44%) grafts had already undergone one or more graft revisions (angioplasty and open). Further details are summarized in Table 2. None of the grafts had been previously stented.

The graft and stent characteristics, along with the outcomes, are summarized in Table 1. The indications for stent placement were significant recoil (7, 39%), graft rupture (6, 33%), residual vein cusps (3, 17%) and aneurysmal degeneration (2, 11%) (Figure 1(a) to (d)). Six grafts required more than one stent, mostly in the case of graft rupture. While covered stents were used for all the graft ruptures, the choice of stent was often based on availability in an emergency and a preference for stents with flexibility. Covered stents successfully arrested haemorrhage in all the cases of graft rupture.

OPEN IN VIEWER

Table 1.

Summary of bypass graft and stent features and outcomes.

S. no.	Outflow artery	Age at intervention	Previous intervention at target	Site	Indication for stent	Description of first stent	Number of stents	Complications/ treatment	Patency (months)	Outcome
1	AT	72	Angioplasty	Distal	Vessel rupture	JOSTENT GraftMaster coronary stent graft system	1	None	12	Patent
2	AT	67	None	Middle	Residual vein cusps	LifeStent®	1	None	12	Patent
3	Peroneal	82	None	Distal	Significant recoil	Astron pulsar	1	None	11	Occluded at 11th month. No further intervention
4	AK P	78	None	Middle	Significant recoil	LifeStent®	1	None	12	Patent
5	BK P	80	None	Proximal	Residual vein cusps	LifeStent®	1	None	12	Patent
6	AK P	71	None	Multiple	Aneurysmal degeneration	Gore® Viabahn® endoprosthesis	2	None	12	Patent
7	PT	71	Angioplasty	Middle	Vessel rupture	Gore® Viabahn® endoprosthesis	1	None	12	Patent
8	BK P	73	Angioplasty	Proximal	Vessel rupture	Gore® Viabahn® endoprosthesis	1	None	12	Patent
9	Peroneal	69	Angioplasty	Distal	Residual vein cusps	Astron pulsar	1	None	9	Restented on 7th month, occluded in 9th month followed by successful bypass
10	AT	86	None	Proximal	Vessel Rupture	Gore® Viabahn® endoprosthesis	2	None	1	Died after 1 month
11	AT	65	None	Proximal	Significant recoil	Zilver® vascular stent	1	None	12	Patent
12	AKP	56	Surgery	Multiple	Significant recoil	Zilver® Vascular Stent	4	Unexplained spasm of distal vessels; 45 mg IA papa	0	Had failed bypass and major Amputation
13	Peroneal	82	Angioplasty	Distal	Significant recoil	Astron pulsar	1	None	0	Major amputation
14	AT	80	None	Multiple	Vessel rupture	Gor® viabahn® endoprosthesis	2	None	4	Major amputation
15	BK P	69	None	Distal	Vessel rupture	Gore ® viabahn® endoprosthesis	3	None	12	Patent
16	AT	68	None	Proximal	significant recoil	Zilver® vascular stent	1	None	8	Occluded on 8th month. No further intervention
17	Peroneal	65	Angioplasty, Thrombolysis	Proximal	Aneurysmal degeneration	Gore ® Viabahn® endoprosthesis	1	None	12	Patent
18	AT	76	Angioplasty	Multiple	Significant Recoil	Zilver® PTX® Drug Eluting Peripheral Stent	2	Distal embolization – thromboaspirated	6	Occluded in 6th month followed by successful bypass

OPEN IN VIEWER

Table 2.

Patient and stent characteristics.

	Number
Overall	18
Age
50–70 years	7
>70 years	11
Previous intervention
No	10
Yes	8
Reason for stent
Significant recoil	7
Vessel rupture	6
Other	5
Stent site
Single	14
Multiple	4
Diameter of first stent
3–5 mm	9
6+mm	9
Number of stents
Single	12
Multiple	6

OPEN IN VIEWER

Figure 1.

(a) Significant recoil after graft angioplasty, (b) graft rupture after angioplasty (c) Vein graft stenosis due to persistent valve leaflet (arrow) (d) aneurysmal degeneration of the vein graft.

Of the four the grafts which showed multi-segmental lesions, three were purely occlusive and one was associated with stenosis in one segment and aneurismal degeneration of multiple segments of the graft. All the three grafts with purely occlusive multisegmental lesions fared poorly with none remaining patent at 12 months and two patients requiring major amputations. Subset analysis was not attempted due to the small numbers in the groups.

Complications were encountered in two patients. The first was unexplained spasm of the distal vessels. This patient had presented with a thrombosed graft which after angioplasty had shown severe recoil in almost all segments of the graft and required a total of four stents. The outcome was probably a reflection of the severity of ischemia. Even a subsequent attempt at bypass failed and the patient needed a major amputation. The second complication was that of distal embolization which was successfully managed with aspiration.

The primary patency at 1, 6 and 12 months was 89%, 71% and 59% respectively (Figure 2). One patient died after the first follow-up. Limb salvage at the end of 1 year was 82% (14/17) in the remaining 17. Only one patient required repeat stenting due to recurrent stenosis during the period of follow-up, but as this was after the sixth month and the graft thrombosed before the end of the follow up, it did not change the primary assisted patency. Of the seven patients with occluded grafts, two were managed without further intervention during the 12-month period of follow-up. A further two had successful redo bypasses using fresh grafts and the remaining three had major amputations. OPEN IN VIEWER

Discussion

There are very few published articles in the literature on stenting of infrainguinal vein grafts. Jahnke et al. ⁷ reported monorail stenting in eight infrainguinal grafts, four of which were vein grafts. There was successful device implantation in all eight grafts with no residual stenosis or procedure related complications. However, one graft occluded in two weeks, four grafts occluded before six months and only two patients had uninterrupted stent patency at 18 and 24 months. A review article on interventions in infrainguinal bypass grafts suggested that stenting of failing bypass grafts is justified in high risk patients or in whom surgery is doomed to fail due to extensive disease or complex lesion morphology. ⁹

Perhaps the largest series on the use of stents in infrainguinal bypasses was from Controneo et al. ¹³ where they described primary stent placement at distal anastomotic stenoses in 21 patients and reported cumulative primary, assisted primary and secondary patency rates of 71%, 81% and 86% respectively at one year. However, there are significant differences with this study, as they included four patients with synthetic grafts (leaving 17 infrainguinal vein grafts) and did not reserve stenting for failed PTA, but advocated its primary use on distal graft stenoses. Instinctively, those patients should have better outcomes.

In this study, we have described the use of stents after failure of PTA with four different situations where they were used for bail-out. Of these significant recoil and graft rupture reflect tough stenotic lesions in veins grafts. Residual vein cusps are a problem peculiar to the use of in-situ and non-reversed vein grafts. Importantly, the stents were successful in bailing out of trouble in all but one patient and achieved hemostasis in all the patients with graft rupture. Moreover, PTA alone would be inappropriate in aneurysmal degeneration of vein grafts with kinks and tortuosity of the grafts causing turbulent flow.

Major limitations of our study include the fact that it is a retrospective review and the small number of patients. On the latter point, this means that the estimates of outcome rates are subject to a wide margin of error and did not allow us to test for the effect of factors such as the number of stents, their diameter, the indication for stenting and the site of the stent, which might display an effect on the outcome. However, to the best of our knowledge, this is the largest series yet on stents in infrainguinal vein grafts. In light of this, we would advocate further research in this area, using a larger cohort to analyse factors affecting patency rates.

Conclusion

The use of bare and covered stents in infrainguinal vein grafts appears safe and effective. They have shown excellent results in the treatment of graft rupture and other complications of graft angioplasty and give acceptable short-term results in patients with few other percutaneous and surgical options.