- Email: [email protected]
Percutaneous transluminal angioplasty by a retrograde subintimal transpopliteal approach
ClinicalRadiology(1994) 49, 824-828
Clinics in Interventional Radiology Percutaneous Transluminal Angioplasty by a Retrograde Subintimal Transpopliteal Approach S. D. H E E N A N , S. J. V I N N I C O M B E , T. M. B U C K E N H A M a n d A.-M. B E L L I
Department of Diagnostic Radiology, St George's Hospital, London We report three cases of femoropopliteal occlusive disease which were successfully recanalized subintimally and retrogradely via the popliteal artery. The merits and fimitations of this approach are discussed. Heenan, S.D., Vinnicombe, S.J., Buckenham, T.M. & Belli, A.-M. (1994). Clinical Radiology 49, 824-828. P e r c u t a n e o u s T r a n s l u m i n a l A n g i o p l a s t y by a Retrograde S u b i n t i m a l T r a n s p o p l i t e a l A p p r o a c h
P e r c u t a n e o u s t r a n s l u m i n a l angioplasty (PTA) has replaced surgery as the t r e a t m e n t of choice in m a n y cases of occlusive peripheral vascular disease. Retrograde p u n c t u r e of the popliteal artery is n o w a well recognized technique for P T A o f the superficial femoral artery (SFA), particularly in patients with S F A origin occlusions or failed antegrade P T A . S u b i n t i m a l passage of the guidewire or catheter is n o t a n i n d i c a t i o n for a b a n d o n i n g the procedure. Indeed several series of i n t e n t i o n a l antegrade s u b i n t i m a l recanalization o f occlusions of the femoropopliteal segment have been reported. We describe a variation of this technique in three patients with S F A occlusions which were recanalized s u b i n t i m a l l y a n d retrogradely via the popliteal artery. F o l l o w - u p a n g i o g r a p h y showed long i n t i m a l dissection flaps. These did n o t a p p e a r to cause any h a e m o d y n a m i c effect a n d the patients r e m a i n e d s y m p t o m a t i c a l l y a n d clinically improved.
CASE REPORTS
Case 1. A 61-year-oldmale ex-smoker, with hypertension and coronary artery disease, presented with increasingly severe bilateral calf claudication(claudicationdistance 100 yards). This was worse on the left and the patient also complainedof nocturnal rest pain in the left foot. An arteriogram in 1987had shown peripheralvascular disease. This was not treated at the time because of the patient's history of angina. The patient had undergone coronary artery vein gaffing in 1991. On examination, only the femoral pulses were palpable and both feet were cool. The ankle-brachial pressure index (ABPI) was 0.6 on the left. Arteriography demonstrated a 12cm occlusion of the distal left SFA with reconstitution above the adductor hiatus (Fig. 1). As an attempt to cross the occlusion with a guidewire via an antegrade approach failed, the patient was turned prone and the popliteal artery punctured. The occlusion was traversed subintimally using a standard angled hydrophilic guidewire (Terumo Corporation, Tokyo) and the lumen re-entered in the proximal SFA. The extraluminal track was then dilated to 6 mm with satisfactory angiographic appearances post-procedure. Glyceryl trinitrate (GTN) (300#g) and 5000 IU of heparin were injected intra-arterially during the procedure. The ABPI had risen to 1.0 at 24 h following angioplasty. At 5 months the ABPI remained 1.0. A check arteriogram shows that the SFA remains patent with good flow and no evidenceof restenosis, although a long dissectionflap is still clearlyvisible(Fig. 2). The patient is currently asymptomatic on the left side. Correspondence to: Dr A.-M. Belli, Department of Diagnostic Radiology, St George's Hospital, BlackshawRoad, London SW170QT.
Fig. 1- Intra-arterial digital subtraction angiogram showing the occlusion of the distal left superficialfemoral artery.
PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY
825
(a) (b) Fig. 3 (a, b) Intra-arterial digital subtraction angiogram showing the left superficialfemoral artery occlusion pre-percutaneous transluminal angioplasty.
months later showed a widelypatent SFA, with a visibleflap. One year later, the patient remains asymptomatic. (a)
(b)
Fig. 2 - (a, b) Check angiogram at 5 months demonstrating the still patent superficialfemoral artery and the long dissection flap (arrows).
Case 2. A 53-year-old male smoker, with no other risk factors, presented with intermittent claudication of the left leg at a distance of 200 yards. Transfemoral arteriography showed generalized disease of the SFA and a 10cm occlusion which extended from the mid-thigh to the adductor canal. The ABPI was 0.6. Extensive steeply angled collaterals were present at the proximal point of the occlusion so PTA was attempted via the transpopliteal approach. The occlusion was successfully traversed subintimally as above and the lumen was re-entered proximal to the lesion (Fig. 3). The occlusion was then dilated to 5mm with satisfactory angiographic appearances (Fig. 4). GTN and beparin were administered intraarterially during the procedure. A follow-up intravenous DSA study 1 month later showed the SFA to be widely patent, though the dissection flap was clearly visible (Fig. 5). The ABPI was over 1.0 and the patient remains asymptomafic at ]0 months. Case 3. A 69-year-oldmale ex-smoker with maturity onset diabetes meUitus presented with steadily worsening intermittent claudication in the right leg. His claudication distance was 30 yards and he had occasional rest pain. The ABPI on the right was 0.5. In the past he had had a right femoropopliteal PTFE graft which required surgical revisionbut had occluded again in 1991,when he became symptomatic. Arteriography confirmed occlusion of the femoropopliteal graft and the native SFA on the right. As the right groin was heavily scarred and the SFA occluded near its origin, popliteal puncture was felt to be most appropriate. The popliteal artery was punctured under fluoroscopic guidance after opacificationvia a left transfemoral aortic injection. The native SFA occlusionwas then traversed by dissectingsubintimallyand the true lumen re-entered proximal to the occlusion allowing a routine PTA. The post-procedural angiographic appearances were satisfactory. One month followingthe procedure the ABPI had risen to 0.72 and the patient was walking over a mile. A check intravenous DSA study 4
DISCUSSION Since the retrograde popliteal p u n c t u r e was first described by T o n n e s e n et al. in 1988, it has provided a useful alternative a p p r o a c h for P T A o f some S F A occlusions [1]. I n d i c a t i o n s for retrograde p u n c t u r e are n u m e r o u s a n d include S F A origin occlusions, adverse collateral a n a t o m y (as in two o f our patients), failure to pass the guidewire antegradely, severe scarring in the groin post-surgery a n d some obese patients where the c o m m o n femoral artery c a n n o t be p u n c t u r e d antegradely. A cross-over technique can be used in some o f these situations b u t m a n i p u l a t i o n from the contralateral side is more difficult. The p u s h i n g force required to traverse certain occlusions m a y lead to the catheter b u c k l i n g in the aorta. Its use is s o m e w h a t limited particularly if the occlusion is flush with the origin of the SFA. A n 81% p r i m a r y angiographic success has been reported by Z a i t o u n et al. for the popliteal a p p r o a c h a l t h o u g h there was n o long-term follow-up, while the report by T o n n e s e n showed a cumulative p a t e n c y rate o f 4 3 % at 1 - 3 years [1,2]. R e p o r t e d complications o f the technique were confined to h a e m a t o m a f o r m a t i o n at the p u n c t u r e site in 4 % . S u b i n t i m a l dissection o f a n arterial occlusion with resulting recanalization has only recently been described. It was first reported by R o s e n t h a l et al. in 1989 using a n activated laser p r o b e [3]. Belli et al. in 1990 reported successful recanalizations in 14 patients following u n i n t e n t i o n a l s u b i n t i m a l dissection, again using the laser p r o b e [4]. I n that study, initial attempts to cross the
826
CLINICAL RADIOLOGY
Fig. 4 - Angiogram showing the long spiralling dissection flap postangioplasty (arrows).
occlusions were with a conventional guidewire and catheter technique. If the vessel wall was entered, the blunt-ended probe was used to dissect back into the true lumen. This was a purely mechanical procedure with no application of laser energy. Only slight pressure resulted in re-entry of the true lumen instead of extending the subintimal dissection further. A 76% primary technical success rate for PTA by subintimal dissection in 71 femoropopliteal occlusions has been reported by Bolia et al. [5]. Initially the technique was only used if the vessel wall was accidentally entered. With more experience, deliberate attempts to enter the subintimal space were made. Long (greater than 15 cm) and hard occlusions, as well as repeated passage into a collateral, were indications for the deliberate dissection. More recently, a study reported on 18 inoperable patients, who had critical lower leg ischaemia and long femoropopliteal occlusions, who underwent intentional
percutaneous extra-luminal recanalizations [6]. There was an initial clinical success rate of 72% but at 6 months this had fallen to 46%. The results of these two studies compare reasonably with those of conventional PTA of femoropopliteal occlusions [7-9]. Long-term patency rates, however, are not yet widely available although cases have remained patent beyond 32 months. Indeed it has been suggested that, as the false lumen created is free of both endothelium and atheroma, there is a theoretical potential to achieve improved longterm results, but this has yet to be shown [5]. It has also been reported in some patients that new collaterals have formed at the site of PTA which may contribute to a favourable long-term outlook [5]. In each of these studies, the femoropopliteal artery occlusions were approached antegradely. We report on three patients who had femoropopliteal occlusions that were not traversed in the conventional antegrade manner. The popliteal artery was either opacified from a contralateral transfemoral aortic or ipsilateral common femoral injection or identified by a Doppler ultrasound needle (Smart needle, Peripheral Systems Group, CA), then punctured using the Seldinger technique. In each of the cases the intima was dissected at the distal end of the occlusion. An angled hydrophilic wire was then used to create a neo-lumen that crossed the occlusion. This was subsequently balloon dilated conventionally. It was our impression that re-entry was easier when travelling retrogradely than in the antegrade direction. At follow-up angiography ranging from 1-5 months, it was interesting to note that the dissection flap could be seen in each case, but did not seem to produce any adverse haemodynamic effect. In fact, all patients to date remain clinically asymptomatic. The theoretical disadvantage of the retrograde subintimal approach is similar to that of the antegrade route, namely damage to collateral vessels by extending the dissection beyond the occlusion. Despite this, in our hands, the technique has proved safe and useful in technically demanding occlusions of the femoropopliteal artery when the antegrade and the intraluminal retrograde approach fails. In such cases, retrograde subintimal passage provides a feasible alternative solution.
REFERENCES
1 T~nnesen KH, Sager P, Karle A et al. Percutaneous transluminal angioplasty of the superficial femoral artery by retrograde catheterization via the popliteal artery. Cardiovascular and Interventional Radiology 1988;11:127-13 l. 2 Zaitoun R, Iyer SS, Lewin RF et al. Percutaneous popliteal approach for angioplasty of superficial femoral artery occlusions. Catheterization and Cardiovascular Diagnosis 1990;21:154-158. 3 Rosenthal E, Curry PVL, Reidy J. Subintimal dissection and false tract formation during successful laser thermal probe ('Hot Tip') angioplasty. Journal of lnterventional Radiology 1989;4:19 22. 4 Belli A-M, Proctor AE, Cumberland DC. Peripheral vascular occlusions: mechanical recanalization with a metal laser probe after guide wire dissection. Radiology 1990;176:539-541. 5 Bolia A, Miles KA, Brennan J e t al. Percutaneous transluminal angioplasty of occlusions of the femoral and popliteal arteries by subintimal dissection. Cardiovascular and Interventional Radiology 1990;13:357-363. 6 Reekers JA, Kromhout JG. Percutaneous intentional extra-luminal recanalization of the femoropopliteal artery (Abstract). Cardiovascular and lnterventional Radiology 1992;15 (Suppl.):S18. 7 Johnston KW. Femoral and popliteal arteries: reanalysis of results of balloon angioplasty. Radiology 1992;183:767 771.
827
PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY
(a)
Fig. 5 - (a, b) Intravenous digital subtraction angiogram demonstrating the patent superficial femoral artery and dissection flap at 1 month.
8 Darcy MD. Reanalyzing the reanalysis of femoropopliteal angioplasty. Radiology 1992;183:621 622. 9 Matsi PJ, Manninen HI, Suhonen MT et al. Chronic critical lowerlimb ischaemia: prospective trial of angioplasty with 1-36 months follow-up. Radiology 1993;188:381 387.
Invited Commentary by Dr P. Taylor There are two separate techniques described in this interesting paper which merit discussion. Firstly the use of the popliteal artery as the access point for a retrograde approach to angioplasty occluded superficial femoral arteries. One of the difficulties is locating the popliteal artery which lies deep in the popliteal fossa just posterior to the tibia and femur. The use of arteriography to locate this seems heavy handed and requires a further puncture elsewhere. The Doppler ultrasound needle seems to be a very elegant solution to this problem. The artery in the popliteal fossa is flanked medially and laterally by its two accompanying
(b)
veins which spiral round the artery. It is not inconceivable that the needle may enter both artery and vein. I wonder if there is any information regarding the subsequent formation of an arteriovenous fistula with this technique. Presumably there needs to be a minimum length of patent popliteal artery above the knee so that the guidewire can be safely positioned in the patent lumen before any attempt is made to cross the occlusion. Is there a minimum length of artery below which the authors would consider the technique to be hazardous? Is it then possible to puncture the popliteal artery below the knee or even the tibio-peroneal trunk? Although no complications were reported, there is always the risk of occluding the artery if difficulties occur at the site of insertion. It is essential that a popliteal aneurysm is excluded before this technique is used otherwise disaster may ensue. Any thrombus could propagate distally into the popliteal run-off, so it would
828
CLINICAL RADIOLOGY
be prudent to perform this technique only in centres where surgeons experienced in grafting to single crural vessels were available on site. The second technique is the deliberate subintimal passage of the guidewire. As mentioned in the text, dissection and occlusion of important patent collaterals may result in deterioration of the leg, particularly if the procedure fails. Any surgical endarterectomy at this site would be closed with a vein patch to ensure an adequate lumen. Logically this technique should be associated with poor results in that the exposed media should be thrombogenic and the compressed atheroma should limit the size of the subsequent effective lumen. Presumably incompressible calcified material would create more problems. Do the authors feel that a contraindication to the subintimal direction technique is the presence of calcification throughout the length of the occluded artery? The post-angioplasty appearances are worrying. Figure 8 is taken immediately and we know that appearances can improve dramatically with time. Figure 3 is taken at 5 months and I wonder whether there are not two significant stenoses, one at the proximal arrow and the second at the most distal part of the artery shown. I would strongly recommend the use of duplex scanning to follow the progress of these angioplasties much in the same way as we screen for graft-related stenoses following bypass procedures. Invited Commentary by Dr M. R. E. Dean These three cases are of interest since they combine two relatively new techniques, subintimal recanalization and retrograde transpopliteal femoral angioplasty. In addition, follow-up angiography demonstrated persistent intimal flaps, a feature of subintimal recanalization which has not been previously described. The complication rate of retrograde transpopliteal femoral angioplasty is reported to be low in expert hands. Published series, however, contain comparatively few cases and wider and less expert use may reveal a higher risk of complications. It has the disadvantage that a puncture site complication which required surgery could convert a potential femoropopliteal graft into a below knee or a femorodistal graft for which the surgical results are less satisfactory. For a retrograde transpopliteal approach the popliteal artery must be punctured either under fluoroscopic guidance, with the
artery opacified by contrast injected via a catheter placed in the aorta from the contralateral side, or the puncture may be performed using the Doppler ultrasound needle. The second method has the advantage of detecting the popliteal vein and thus one can avoid puncturing the artery through the vein with the theoretical risk of an arteriovenous fistula. The main indication for the transpopliteal approach is failure of the antegrade approach due to large collaterals at the site of the occlusion. In this situation the contralateral approach will not offer any advantage. The decision to use the transpopliteal approach will then be made in conjunction with the vascular surgeon taking into account the contraindications to performing a graft. When the ipsilateral approach is contraindicated due to disease in the common femoral or proximal superficial femoral artery, obesity or severe scarring in the groin from previous surgery, either the transpopliteal or the contralateral approach can be considered. The contralateral approach is difficult, however, for more distal superficial femoral artery occlusions or tight stenoses as the anatomy of the bifurcation may cause the guide-wire to buckle during attempts to advance the catheter through the lesion. The choice between the contralateral approach and the retrograde popliteal approach must then depend on the anatomy of the aortic bifurcation and the site and length of the lesion to be treated. Femoral artery puncture, antegrade or retrograde, is still a proven and safe approach. In these cases the authors state that the subintimal recanalization was inadvertent although the approach of deliberate subintimal recanalization has been advocated by Bolia. The ability to re-enter the lumen beyond the dissection is important as in earlier years a dissection meant abandonment of the procedure. The initial results of subintimal recanalization in long occlusions are good but there is no evidence that long-term patency is improved. The danger of subintimal recanalization lies in occluding important collaterals without regaining the lumen, in which case there is likely to be a worsening of the patient's condition. Retrograde transpopliteal angioplasty and subintimal recanalization are both relatively new and further time and experience are needed to assess the safety and results of both. Certainly they should not be attempted by interventional radiologists without wide experience of more established methods.
Clinics in Interventional Radiology Percutaneous Transluminal Angioplasty by a Retrograde Subintimal Transpopliteal Approach S. D. H E E N A N , S. J. V I N N I C O M B E , T. M. B U C K E N H A M a n d A.-M. B E L L I
Department of Diagnostic Radiology, St George's Hospital, London We report three cases of femoropopliteal occlusive disease which were successfully recanalized subintimally and retrogradely via the popliteal artery. The merits and fimitations of this approach are discussed. Heenan, S.D., Vinnicombe, S.J., Buckenham, T.M. & Belli, A.-M. (1994). Clinical Radiology 49, 824-828. P e r c u t a n e o u s T r a n s l u m i n a l A n g i o p l a s t y by a Retrograde S u b i n t i m a l T r a n s p o p l i t e a l A p p r o a c h
P e r c u t a n e o u s t r a n s l u m i n a l angioplasty (PTA) has replaced surgery as the t r e a t m e n t of choice in m a n y cases of occlusive peripheral vascular disease. Retrograde p u n c t u r e of the popliteal artery is n o w a well recognized technique for P T A o f the superficial femoral artery (SFA), particularly in patients with S F A origin occlusions or failed antegrade P T A . S u b i n t i m a l passage of the guidewire or catheter is n o t a n i n d i c a t i o n for a b a n d o n i n g the procedure. Indeed several series of i n t e n t i o n a l antegrade s u b i n t i m a l recanalization o f occlusions of the femoropopliteal segment have been reported. We describe a variation of this technique in three patients with S F A occlusions which were recanalized s u b i n t i m a l l y a n d retrogradely via the popliteal artery. F o l l o w - u p a n g i o g r a p h y showed long i n t i m a l dissection flaps. These did n o t a p p e a r to cause any h a e m o d y n a m i c effect a n d the patients r e m a i n e d s y m p t o m a t i c a l l y a n d clinically improved.
CASE REPORTS
Case 1. A 61-year-oldmale ex-smoker, with hypertension and coronary artery disease, presented with increasingly severe bilateral calf claudication(claudicationdistance 100 yards). This was worse on the left and the patient also complainedof nocturnal rest pain in the left foot. An arteriogram in 1987had shown peripheralvascular disease. This was not treated at the time because of the patient's history of angina. The patient had undergone coronary artery vein gaffing in 1991. On examination, only the femoral pulses were palpable and both feet were cool. The ankle-brachial pressure index (ABPI) was 0.6 on the left. Arteriography demonstrated a 12cm occlusion of the distal left SFA with reconstitution above the adductor hiatus (Fig. 1). As an attempt to cross the occlusion with a guidewire via an antegrade approach failed, the patient was turned prone and the popliteal artery punctured. The occlusion was traversed subintimally using a standard angled hydrophilic guidewire (Terumo Corporation, Tokyo) and the lumen re-entered in the proximal SFA. The extraluminal track was then dilated to 6 mm with satisfactory angiographic appearances post-procedure. Glyceryl trinitrate (GTN) (300#g) and 5000 IU of heparin were injected intra-arterially during the procedure. The ABPI had risen to 1.0 at 24 h following angioplasty. At 5 months the ABPI remained 1.0. A check arteriogram shows that the SFA remains patent with good flow and no evidenceof restenosis, although a long dissectionflap is still clearlyvisible(Fig. 2). The patient is currently asymptomatic on the left side. Correspondence to: Dr A.-M. Belli, Department of Diagnostic Radiology, St George's Hospital, BlackshawRoad, London SW170QT.
Fig. 1- Intra-arterial digital subtraction angiogram showing the occlusion of the distal left superficialfemoral artery.
PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY
825
(a) (b) Fig. 3 (a, b) Intra-arterial digital subtraction angiogram showing the left superficialfemoral artery occlusion pre-percutaneous transluminal angioplasty.
months later showed a widelypatent SFA, with a visibleflap. One year later, the patient remains asymptomatic. (a)
(b)
Fig. 2 - (a, b) Check angiogram at 5 months demonstrating the still patent superficialfemoral artery and the long dissection flap (arrows).
Case 2. A 53-year-old male smoker, with no other risk factors, presented with intermittent claudication of the left leg at a distance of 200 yards. Transfemoral arteriography showed generalized disease of the SFA and a 10cm occlusion which extended from the mid-thigh to the adductor canal. The ABPI was 0.6. Extensive steeply angled collaterals were present at the proximal point of the occlusion so PTA was attempted via the transpopliteal approach. The occlusion was successfully traversed subintimally as above and the lumen was re-entered proximal to the lesion (Fig. 3). The occlusion was then dilated to 5mm with satisfactory angiographic appearances (Fig. 4). GTN and beparin were administered intraarterially during the procedure. A follow-up intravenous DSA study 1 month later showed the SFA to be widely patent, though the dissection flap was clearly visible (Fig. 5). The ABPI was over 1.0 and the patient remains asymptomafic at ]0 months. Case 3. A 69-year-oldmale ex-smoker with maturity onset diabetes meUitus presented with steadily worsening intermittent claudication in the right leg. His claudication distance was 30 yards and he had occasional rest pain. The ABPI on the right was 0.5. In the past he had had a right femoropopliteal PTFE graft which required surgical revisionbut had occluded again in 1991,when he became symptomatic. Arteriography confirmed occlusion of the femoropopliteal graft and the native SFA on the right. As the right groin was heavily scarred and the SFA occluded near its origin, popliteal puncture was felt to be most appropriate. The popliteal artery was punctured under fluoroscopic guidance after opacificationvia a left transfemoral aortic injection. The native SFA occlusionwas then traversed by dissectingsubintimallyand the true lumen re-entered proximal to the occlusion allowing a routine PTA. The post-procedural angiographic appearances were satisfactory. One month followingthe procedure the ABPI had risen to 0.72 and the patient was walking over a mile. A check intravenous DSA study 4
DISCUSSION Since the retrograde popliteal p u n c t u r e was first described by T o n n e s e n et al. in 1988, it has provided a useful alternative a p p r o a c h for P T A o f some S F A occlusions [1]. I n d i c a t i o n s for retrograde p u n c t u r e are n u m e r o u s a n d include S F A origin occlusions, adverse collateral a n a t o m y (as in two o f our patients), failure to pass the guidewire antegradely, severe scarring in the groin post-surgery a n d some obese patients where the c o m m o n femoral artery c a n n o t be p u n c t u r e d antegradely. A cross-over technique can be used in some o f these situations b u t m a n i p u l a t i o n from the contralateral side is more difficult. The p u s h i n g force required to traverse certain occlusions m a y lead to the catheter b u c k l i n g in the aorta. Its use is s o m e w h a t limited particularly if the occlusion is flush with the origin of the SFA. A n 81% p r i m a r y angiographic success has been reported by Z a i t o u n et al. for the popliteal a p p r o a c h a l t h o u g h there was n o long-term follow-up, while the report by T o n n e s e n showed a cumulative p a t e n c y rate o f 4 3 % at 1 - 3 years [1,2]. R e p o r t e d complications o f the technique were confined to h a e m a t o m a f o r m a t i o n at the p u n c t u r e site in 4 % . S u b i n t i m a l dissection o f a n arterial occlusion with resulting recanalization has only recently been described. It was first reported by R o s e n t h a l et al. in 1989 using a n activated laser p r o b e [3]. Belli et al. in 1990 reported successful recanalizations in 14 patients following u n i n t e n t i o n a l s u b i n t i m a l dissection, again using the laser p r o b e [4]. I n that study, initial attempts to cross the
826
CLINICAL RADIOLOGY
Fig. 4 - Angiogram showing the long spiralling dissection flap postangioplasty (arrows).
occlusions were with a conventional guidewire and catheter technique. If the vessel wall was entered, the blunt-ended probe was used to dissect back into the true lumen. This was a purely mechanical procedure with no application of laser energy. Only slight pressure resulted in re-entry of the true lumen instead of extending the subintimal dissection further. A 76% primary technical success rate for PTA by subintimal dissection in 71 femoropopliteal occlusions has been reported by Bolia et al. [5]. Initially the technique was only used if the vessel wall was accidentally entered. With more experience, deliberate attempts to enter the subintimal space were made. Long (greater than 15 cm) and hard occlusions, as well as repeated passage into a collateral, were indications for the deliberate dissection. More recently, a study reported on 18 inoperable patients, who had critical lower leg ischaemia and long femoropopliteal occlusions, who underwent intentional
percutaneous extra-luminal recanalizations [6]. There was an initial clinical success rate of 72% but at 6 months this had fallen to 46%. The results of these two studies compare reasonably with those of conventional PTA of femoropopliteal occlusions [7-9]. Long-term patency rates, however, are not yet widely available although cases have remained patent beyond 32 months. Indeed it has been suggested that, as the false lumen created is free of both endothelium and atheroma, there is a theoretical potential to achieve improved longterm results, but this has yet to be shown [5]. It has also been reported in some patients that new collaterals have formed at the site of PTA which may contribute to a favourable long-term outlook [5]. In each of these studies, the femoropopliteal artery occlusions were approached antegradely. We report on three patients who had femoropopliteal occlusions that were not traversed in the conventional antegrade manner. The popliteal artery was either opacified from a contralateral transfemoral aortic or ipsilateral common femoral injection or identified by a Doppler ultrasound needle (Smart needle, Peripheral Systems Group, CA), then punctured using the Seldinger technique. In each of the cases the intima was dissected at the distal end of the occlusion. An angled hydrophilic wire was then used to create a neo-lumen that crossed the occlusion. This was subsequently balloon dilated conventionally. It was our impression that re-entry was easier when travelling retrogradely than in the antegrade direction. At follow-up angiography ranging from 1-5 months, it was interesting to note that the dissection flap could be seen in each case, but did not seem to produce any adverse haemodynamic effect. In fact, all patients to date remain clinically asymptomatic. The theoretical disadvantage of the retrograde subintimal approach is similar to that of the antegrade route, namely damage to collateral vessels by extending the dissection beyond the occlusion. Despite this, in our hands, the technique has proved safe and useful in technically demanding occlusions of the femoropopliteal artery when the antegrade and the intraluminal retrograde approach fails. In such cases, retrograde subintimal passage provides a feasible alternative solution.
REFERENCES
1 T~nnesen KH, Sager P, Karle A et al. Percutaneous transluminal angioplasty of the superficial femoral artery by retrograde catheterization via the popliteal artery. Cardiovascular and Interventional Radiology 1988;11:127-13 l. 2 Zaitoun R, Iyer SS, Lewin RF et al. Percutaneous popliteal approach for angioplasty of superficial femoral artery occlusions. Catheterization and Cardiovascular Diagnosis 1990;21:154-158. 3 Rosenthal E, Curry PVL, Reidy J. Subintimal dissection and false tract formation during successful laser thermal probe ('Hot Tip') angioplasty. Journal of lnterventional Radiology 1989;4:19 22. 4 Belli A-M, Proctor AE, Cumberland DC. Peripheral vascular occlusions: mechanical recanalization with a metal laser probe after guide wire dissection. Radiology 1990;176:539-541. 5 Bolia A, Miles KA, Brennan J e t al. Percutaneous transluminal angioplasty of occlusions of the femoral and popliteal arteries by subintimal dissection. Cardiovascular and Interventional Radiology 1990;13:357-363. 6 Reekers JA, Kromhout JG. Percutaneous intentional extra-luminal recanalization of the femoropopliteal artery (Abstract). Cardiovascular and lnterventional Radiology 1992;15 (Suppl.):S18. 7 Johnston KW. Femoral and popliteal arteries: reanalysis of results of balloon angioplasty. Radiology 1992;183:767 771.
827
PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY
(a)
Fig. 5 - (a, b) Intravenous digital subtraction angiogram demonstrating the patent superficial femoral artery and dissection flap at 1 month.
8 Darcy MD. Reanalyzing the reanalysis of femoropopliteal angioplasty. Radiology 1992;183:621 622. 9 Matsi PJ, Manninen HI, Suhonen MT et al. Chronic critical lowerlimb ischaemia: prospective trial of angioplasty with 1-36 months follow-up. Radiology 1993;188:381 387.
Invited Commentary by Dr P. Taylor There are two separate techniques described in this interesting paper which merit discussion. Firstly the use of the popliteal artery as the access point for a retrograde approach to angioplasty occluded superficial femoral arteries. One of the difficulties is locating the popliteal artery which lies deep in the popliteal fossa just posterior to the tibia and femur. The use of arteriography to locate this seems heavy handed and requires a further puncture elsewhere. The Doppler ultrasound needle seems to be a very elegant solution to this problem. The artery in the popliteal fossa is flanked medially and laterally by its two accompanying
(b)
veins which spiral round the artery. It is not inconceivable that the needle may enter both artery and vein. I wonder if there is any information regarding the subsequent formation of an arteriovenous fistula with this technique. Presumably there needs to be a minimum length of patent popliteal artery above the knee so that the guidewire can be safely positioned in the patent lumen before any attempt is made to cross the occlusion. Is there a minimum length of artery below which the authors would consider the technique to be hazardous? Is it then possible to puncture the popliteal artery below the knee or even the tibio-peroneal trunk? Although no complications were reported, there is always the risk of occluding the artery if difficulties occur at the site of insertion. It is essential that a popliteal aneurysm is excluded before this technique is used otherwise disaster may ensue. Any thrombus could propagate distally into the popliteal run-off, so it would
828
CLINICAL RADIOLOGY
be prudent to perform this technique only in centres where surgeons experienced in grafting to single crural vessels were available on site. The second technique is the deliberate subintimal passage of the guidewire. As mentioned in the text, dissection and occlusion of important patent collaterals may result in deterioration of the leg, particularly if the procedure fails. Any surgical endarterectomy at this site would be closed with a vein patch to ensure an adequate lumen. Logically this technique should be associated with poor results in that the exposed media should be thrombogenic and the compressed atheroma should limit the size of the subsequent effective lumen. Presumably incompressible calcified material would create more problems. Do the authors feel that a contraindication to the subintimal direction technique is the presence of calcification throughout the length of the occluded artery? The post-angioplasty appearances are worrying. Figure 8 is taken immediately and we know that appearances can improve dramatically with time. Figure 3 is taken at 5 months and I wonder whether there are not two significant stenoses, one at the proximal arrow and the second at the most distal part of the artery shown. I would strongly recommend the use of duplex scanning to follow the progress of these angioplasties much in the same way as we screen for graft-related stenoses following bypass procedures. Invited Commentary by Dr M. R. E. Dean These three cases are of interest since they combine two relatively new techniques, subintimal recanalization and retrograde transpopliteal femoral angioplasty. In addition, follow-up angiography demonstrated persistent intimal flaps, a feature of subintimal recanalization which has not been previously described. The complication rate of retrograde transpopliteal femoral angioplasty is reported to be low in expert hands. Published series, however, contain comparatively few cases and wider and less expert use may reveal a higher risk of complications. It has the disadvantage that a puncture site complication which required surgery could convert a potential femoropopliteal graft into a below knee or a femorodistal graft for which the surgical results are less satisfactory. For a retrograde transpopliteal approach the popliteal artery must be punctured either under fluoroscopic guidance, with the
artery opacified by contrast injected via a catheter placed in the aorta from the contralateral side, or the puncture may be performed using the Doppler ultrasound needle. The second method has the advantage of detecting the popliteal vein and thus one can avoid puncturing the artery through the vein with the theoretical risk of an arteriovenous fistula. The main indication for the transpopliteal approach is failure of the antegrade approach due to large collaterals at the site of the occlusion. In this situation the contralateral approach will not offer any advantage. The decision to use the transpopliteal approach will then be made in conjunction with the vascular surgeon taking into account the contraindications to performing a graft. When the ipsilateral approach is contraindicated due to disease in the common femoral or proximal superficial femoral artery, obesity or severe scarring in the groin from previous surgery, either the transpopliteal or the contralateral approach can be considered. The contralateral approach is difficult, however, for more distal superficial femoral artery occlusions or tight stenoses as the anatomy of the bifurcation may cause the guide-wire to buckle during attempts to advance the catheter through the lesion. The choice between the contralateral approach and the retrograde popliteal approach must then depend on the anatomy of the aortic bifurcation and the site and length of the lesion to be treated. Femoral artery puncture, antegrade or retrograde, is still a proven and safe approach. In these cases the authors state that the subintimal recanalization was inadvertent although the approach of deliberate subintimal recanalization has been advocated by Bolia. The ability to re-enter the lumen beyond the dissection is important as in earlier years a dissection meant abandonment of the procedure. The initial results of subintimal recanalization in long occlusions are good but there is no evidence that long-term patency is improved. The danger of subintimal recanalization lies in occluding important collaterals without regaining the lumen, in which case there is likely to be a worsening of the patient's condition. Retrograde transpopliteal angioplasty and subintimal recanalization are both relatively new and further time and experience are needed to assess the safety and results of both. Certainly they should not be attempted by interventional radiologists without wide experience of more established methods.