Eur I Vasc Surg 3,209-211 (1989)

Limitations of Percutaneous Transluminal Angioplasty in the Treatment of Femoro-distal Graft Stenoses

J. F. Thompson, M. D. i c S h a n e , V. Gazzard, The late P. C. Cl i f ford and A. D. B. Chant

Vascular Surgical Unit, Royal South Hants Hospital, Southampton, U.K.

Non-invasive follow-up of 94 femoro-distal reconstructions has identified 14 graft related stenoses (4 proximal anastomotic, 4 intragraft and 7 distal anastomotic). Stenoses treated by percutaneous transluminal angioplasty (PTA) recurred by 6 months. Stenoses treated by surgical revision remained satisfactory with a mean follow-up of 13 months. In this series, formal surgical revision appears to be superior to PTA for the treatment of graft stenoses.

Key Words: Percutaneous transluminal angioplasty; Femoro-distal bypass graft; Graft stenosis.

In t roduct ion

Percutaneous transluminal angioplasty (PTA) of graft related stenoses is an attractive method of salvaging the failing femoro-popliteal bypass graft without the need for formal operation and the immediate results of graft PTA have been encouraging. ~, 2, 3

Reports of patency following angioplasty 4'5 rely on symptomatic graft occlusion or a fall in ankle brachial pressure index (ABI) as an end point, rather than recur- rence of the stenosis.

Up to 50% of haemodynamically significant graft stenoses which have been defined by objective methods may be asymptomatic. 6 Doppler derived ABI can detect failing or occluded grafts,7 but vessel calcification and a normal physiological variation of up to 4-0.15 may partly explain the inability of ABI to detect all arteriogra- phically proven stenoses. Stressed ABI, particularly if used in conjunction with a standardised exercise test such as that of Laing and Greenhalgh 8 may be more dis- criminant. However, Duplex scanning (the combination of real time and Doppler ultrasound), can identify the site, extent and also grade the severity of the stenosis. This is of practical importance because stenoses, even if non-

* Presented at the 2nd Annual Meeting of the European Society for Vascular Surgery, Rotterdam, September 1988.

0950-821X/89/030209 + 03 $03.00/0 © 1989 Grune & Stratton Ltd

haemodynamical ly significant, may progress to threaten graft patency.

Clinical assessment, ABI and duplex have been used to prospectively audit the results of t reatment of a group of stenoses identified following 110 femoro-distal recon- structions.

M e t h o d s

110 femoro-distal reconstructions were performed between November 1985 and March 1986 and 16 patients were not included in the study for the following reasons:

Inpatient death Amputat ion (early failure) Re-operation required Did not attend follow-up

There were 94 grafts in 90 patients. Demographic details are given in Table 1. Fifty-one per cent of the grafts were in situ vein. Only 1 was reversed, and the remainder were mainly externally supported Dacron with 70% anastom- osed to below knee vessels.

Follow-up was by clinical assessment, resting and post exercise ABI and Duplex, 1 month postoperation and at three monthly intervals. Duplex imaging was per-

210 J.F. Thompson e t al .

Table 1

Age 69 (45-88)

Pre-op ABI 0.51 +0.02

Diabetic 11%

Rest pain/Gangrene/Ulcer 47%

Claudication < 50 M 30% >50M 23%

Table 2. Cumulative restenosis rate following revision

Months post procedure

Site Treatment n 1 2 3 4 5 6 ........ 9

Proximal anastomosis Revise 4 0

[ntra graft PTA 4 1 2 4 4

Distal anastomosis PTA 7 2 3 3 4 4 7 7

formed using a 3.5 or 5.0MHz scanning head, and Doppler waveforms were obtained using 4.0 or 8.0 MHz pencil probes. Inflow status, the whole length of the graft, run-off and both anastomoses were visualised if possible. Damping of the Doppler waveform, first component fre- quency shift and turbulent flow patterns were used in addition to morphological data to identify and grade sten- oses. We have found the coefficient of variation of Duplex derived volume flow measurements to be high and there- fore unreliable. Peak systolic Doppler frequency is inver- sely related to vessel diameter, and we have found the first component frequency shift to be reliable and repro- ducible. 9

Stenoses were identified in 14 grafts (15%) with 4 at the proximal anastomosis, 4 within the graft, and 7 at the distal anastomosis. All stenoses were confirmed by digital subtraction angiography but only two of the patients were symptomatic.

Proximal stenoses were revised surgically by patch angioplasty or ilio-femoral jump graft but intra-graft and distal anastomotic lesions were treated by PTA. A suc- cessful immediate result was confirmed by angiography, post procedure ABI and duplex in all cases.

Results

Revised proximal anastomoses (all in vein grafts) were patent at a mean follow up of 13 months (min 9 months).

All 4 stenoses within in-situ vein grafts had recurred by 6 months, and all seven distal anastomotic stenoses (5 vein) had returned within 6 months (Table 2). Failure was defined as the return of duplex parameters to pre- PTA levels or worse..

Discussion

Despite the relatively small number of lesions identified in this study, polarisation of the results suggests that PTA is not successful in the treatment of graft related stenoses. Surgical revision involves excision of the stenotic lesion under direct vision. Karmody and Leather, among others, have treated stenoses of in-situ grafts by vein patch angio- plasty with good results 1° and these data support this approach to the problem.

PTA, first introduced by Dotter in 1964 using rigid dilators was refined by the introduction of balloon dila- tion by Gruntzig in 1976. The technique is dependent on balloon diameter and inflation pressure, and is effective only if Youngs Modulus of elasticity is exceeded. A lasting effect is accompanied by elongation of muscle fibres and distortion of elastin in the cells of the media. Excessive force however leads to disruption and fibrosis, n

Graft stenoses differ histologically from atheroscler- otic lesions. Whatever their aetiology a high fibrotic com- ponent is seen. During graft PTA considerable force is required to dilate the lesion, which may be painful for the patient. Also, the lesion does not "crack" open like an atherosclerotic arterial stenosis and may take some time to dilate.

Contraction of myofibroblasts within the scar tissue following PTA could explain these disappointing results. A further cohort of patients is currently under study, and preliminary review of the results suggests that graft related stenoses are best treated by surgical revision.

References

1 KALMAN PG, SNIDERMAN KW. Salvage of in situ femoropopliteal and femorotibial saphenous vein bypass with interventional radiology. J Vase Surg 1988 ; 7:429-432.

2 BUCKER GJ, WENKER JC, RUES CR, REILLY MK, BENDICK RJ, COCKERILL EM. Percutaneous angioplasty and valvectomy in a failing in-situ bypass graft. Radio11986;159:431-433.

3 KINNINSON ML, PULER BA, KAUFMAN SL et al. In-situ saphenous vein bypass grafts: Angiographic evaluation and interventional repair of complications. Radiol 1986; 160: 727-730.

4 VEITH FJ, WEISER RK, GUPTA SK et al. Diagnosis and management of failing lower extremity arterial reconstructions prior to graft occlu- sion. ] Cardiovasc Surg 1986 ;25 : 381-384.

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Limitations of Percutaneous Transluminal Angioplasty 211

KG, RUTT DL. Early diagnosis of femoro-distal graft stenoses. Br ] Surg 1987;74:268-270.

7 SAMSON RH, (JUPTA SK, VEITH FJ, SellER LA, ASCER A. Evaluation of graft patency utilising the ankle brachial pressure indices and angle pulse volume recording amplitude. Am ] Surg 1984; 147:786-787 .

8 LAING SP, GREENnALGn RM. Standard exercise test to assess peri- pheral vascular disease. Br Med ] 1980; 1 : 13-16.

9 MCSHANE MD. MS Thesis. University of London, 1989.

10 LEATHER RP, KARMODY AM. In-situ saphenous vein arterial bypass for the treatment of limb ischaemia. In: Bergan JJ, Yao JST, eds (1987) Yearbook of Vascular Surgery. Chicago: Year Book Medical Publishers, Inc, 1986; 175-219.

11 CASTANEDA-ZUNIGA WR, FORMANCK A, TADAVARTHY M, et al. The mechanisms of balloon angioplasty. Radio l 1980; 135 : 565-571.

Accepted 29 November 1988

EurJ Vase Surg Vol 3, June 1989