Received: 30 April 2002Revised: 13 September 2002 Accepted: 11 October 2002 Published online: 22 November 2002© Springer-Verlag 2002

Abstract The puncture of the popli-teal artery for percutaneous inter-vention is usually performed underfluoroscopic guidance or with theassistance of percutaneous ultra-sound to avoid accidental arteriove-nous fistulas. We present our experi-ence in 119 cases with the use of a Doppler ultrasound equipped Seldinger needle (SMART needle)for the detection and puncture of thepopliteal artery. In 119 interventionsin 103 patients, the puncture of thepopliteal artery was performed withthe SMART needle. The puncturewas successful in 94.1% (112 of119) of cases. Six (5.2%) complica-tions occurred during puncture: fourhematomas (no therapy required)and two arteriovenous fistulas (treat-ed by manual compression solely).The subsequent 112 interventions in103 patients [98 percutaneous trans-

luminal angioplasty (PTA), 8 PTAwith stent implantations, 4 PTA withthrombolysis, 2 thrombolyses] weretechnically successful in 79.5% (89 of 112). The SMART-needle-guided popliteal puncture showed to be safe, fast, and easy to perform,which allowed the use of this tech-nique by radiologists in training.The rates of success and complica-tions are comparable to reported results for other visualization techniques, whereas time, effort, and training required are lower. This may contribute to a more wide-spread use of the transpopliteal access for interventions and there-fore offers a therapeutic option inaddition to vascular surgery.

Keywords Puncture · Popliteal artery · Radiology · Interventional ·Ultrasonography · Doppler

Eur Radiol (2003) 13:1972–1978DOI 10.1007/s00330-002-1749-8 VA S C U L A R – I N T E RV E N T I O N A L

Alexander KlugeKlaus RauberAndreas BreitheckerWigbert S. RauGeorg Bachmann

Puncture of the popliteal artery using a Doppler-equipped (SMART) needle in transpopliteal interventions

Introduction

The most commonly used approach for percutaneoustransluminal angioplasty (PTA) at the lower limb is theantegrade transfemoral puncture. This approach is notsuited for all patients: combined iliac and femoral le-sions [1, 2, 3, 4, 5, 6, 7], an occlusion or a high takeoffof the origin of the superficial femoral artery (SFA) [3,5], or severe obesity limits or precludes the transfemoralapproach. A graft prosthesis in the groin raises the riskof complications [8, 9]. The limited forward pressurepossible with the crossover technique [10, 11], otherwisesuited for patients with proximal stenosis of the SFAmay not suffice to cross occluded segments.

A retrograde transpopliteal approach has proved to bea reliable alternative vascular access in patients not suited for transfemoral intervention or with combinedfemoral and iliac lesions [1, 2, 3, 4, 7]. If an antegradetransfemoral puncture failed, the transpopliteal approachmay be used as well [5, 6].

For this popliteal approach, we evaluated the use of aDoppler-equipped SMART needle device for puncture ofthe popliteal artery in 119 planned interventions. We expected the SMART needle technique to require lesspreparation, fewer precautions, and a less experiencedexaminer as compared with the established methods ofpopliteal puncture, mainly fluoroscopic guidance, andpercutaneous Duplex ultrasound-guided puncture. The

A. Kluge (✉) · G. BachmannDepartment of Radiology, Kerckhoff-Klinik, Benekestrasse 2–8,61032 Bad Nauheim, Germanye-mail: alexander.kluge@kerckhoff.med.uni-giessen.deTel.: +49-6032-9962420Fax: +49-6032-9962433

K. RauberDepartment of Radiology, Klinikum Wetzlar, 35578 Wetzlar, Germany

A. Breithecker · W.S. RauDepartment of Diagnostic Radiology, University of Giessen, 35392 Giessen,Germany

1973

All steps necessary for the popliteal puncture were performedwith the patient in prone position after proper positioning and ster-ilization. Firstly, the course of the popliteal artery is established bypalpation. Then the needle tip with the inserted transducer ismoved over the skin of the popliteal space to identify the arterialand venous flow signal. When the popliteal artery is localized, theneedle penetrates the skin under local anesthesia. The needle tip isthen pivoted until a pure arterial flow signal is monitored. By per-taining the arterial flow signal, the needle is advanced successive-ly while modifying the direction accordingly. The puncture of thevessel wall causes a characteristic acoustic signal. The core of theneedle containing the ultrasound crystal is then retracted and astandard guide wire is advanced through the needle. Thenceforth,the intervention continues in standard Seldinger technique with introduction of guide wire and vascular sheath.

Patients

One hundred three consecutive patients (81 men, 21 women; meanage 61 years, age range 48–92 years) were prospectively included.All patients were referred for interventional therapy for peripheralocclusive arterial disease (PAOD). Inclusion criteria was a PAODrequiring a transpopliteal intervention. This transpopliteal ap-proach was chosen in patients not suited for transfemoral interven-tion, especially those suffering from combined iliac and femorallesions or those with an occlusion or a high takeoff of the origin ofthe SFA [3, 5] or severely obese patients. Graft prosthesis in thegroin does not preclude puncture, but is charged with a higher riskof complications, e.g., hematomas. If possible, the transpoplitealapproach was chosen in these patients, too.

Fig. 1a, b Doppler-equippedSeldinger needle. a The needlecore with the transducer crystalon its tip (right) is retractedfrom the Seldinger needle(left). b The Doppler ultra-sound monitor wrapped in asterile bag

real-time guidance of this technique should result in alower complication rate.

Materials and methods

Device

The Doppler-needle system (SMART needle monitor, PeripheralSystems Group, Mountain View, Calif.) consists of two parts: one portable, reusable Doppler monitor; and one disposable 18-GSeldinger puncture needle with an integrated ultrasound trans-ducer at the tip (Fig. 1 shows the principle). The ultrasound moni-tor can be wrapped in a sterile single use plastic bag, allowing manipulation of the monitor and adjustments under sterile condi-tions at any time before and during the intervention by the per-forming radiologist. The 14-MHz continuous-wave Doppler signalallows the localization of arterial and venous vascular flow. As thepenetration of the ultrasound beam reaches approximately 3 cmand the beam opens at an angle of 15–20°, it can be used for per-cutaneous localization of the popliteal artery as well as for subcu-taneous steering. The cost amounts to US$1500 for the Ultrasoundmonitor and approximately $80 for the needle. Although designedfor single use only, the resterilization of the needle is possible. Thesound quality degrades with every resterilization, but the loss iswell tolerable after single resterilization.

Puncture

The popliteal punctures in this study using the SMART needlewere performed by board-reviewed radiologists and by residentsin their third and forth years with experience in intervention radi-ology. The learning curve for popliteal punctures using theSMART needle required several punctures under strict guidanceand supervision, and further interventions could be performed autonomously. Former conventional popliteal punctures usingblind puncture or fluoroscopic guidance had been performed exclusively by board-reviewed radiologists with many years of experience in interventional radiology.

1974

Transpopliteal interventions accounted for 9.6% of all per-formed interventions at the lower limbs (119 of 1244 interven-tions).

No patient was excluded from the study, and no other tech-nique for localization of the popliteal artery was used.

One hundred nineteen transpopliteal punctures were intended;16 patients were treated on both legs in two separate sessions. Aprimary transpopliteal approach was planned in 101 interventions(84.9% of all examinations). A secondary transpopliteal approachwas necessary in 18 (15.1%) cases. The transfemoral puncture hadfailed in 9 cases: 3 bypass grafts in the inguinal area as well as 6precedent punctures in the groin precluded the transfemoral punc-ture. These punctures had been made for diagnostic angiographiesin the preceding week.

The localizations of the 116 lesions treated are listed in Table 1.

All patients were referred by the angiology department of ourclinic. Pre-interventional diagnostics included evaluation of symp-toms, clinical condition, ergometry, and peripheral blood pressure.The stage of PAOD was IIb (Fontaine) or worse in all patients. Allpatients had prior diagnostic intraarterial angiography in our de-partment not older than 3 weeks. All patients were hospitalized forthe intervention. Clinical condition of the treated limb, the situa-tion at the site of puncture, and eventual complications were examined directly after as well as 24 h after intervention in all patients. Color-coded ultrasound control of the puncture site wasonly performed if clinical examination and auscultation led to thesuspicion of arteriovenous (AV) fistula. Informed consent was obtained from every patient.

Technical success of the intervention was defined as a residualstenosis of less than 50% of the vessel diameter after percutaneousangioplasty or after recanalization and percutaneous angioplasty.The success rate of popliteal puncture was analyzed on an inten-tion-to-treat basis. Success rate and frequency of complications ofthe interventions were correlated to the number of performed interventions.

Results

Patient preparation and preparation of the punctureequipment were performed simultaneously. The averagetime from attempt at localization of the popliteal arteryuntil a guide wire could be introduced was 80 s (range20 s to 5 min). No repositioning of the patient or modifi-cation in the angiography room was necessary for thefollowing intervention.

Of all 119 planned punctures, 115 were performed.Four punctures (4 of 119, 3.4%) were abandoned be-cause arterial and venous Doppler signals could not beseparated as the popliteal vein superimposed the popli-teal artery entirely. A puncture in this situation mighthave resulted in an AV fistula. Of the remaining 115 per-

formed punctures, 112 were successful and the vascularsheath could be introduced into the popliteal artery, and3 punctures (3 of 119, 2.5%) failed. An intervention was postponed in 4 of the 7 patients without successfulpuncture; 3 patients were presented to the vascular sur-geon. The overall success rate was 94.1% (112 of 119).Figure 2 demonstrates a transpopliteal recanalization of aproximal SFA occlusion.

Six complications of the puncture occurred. Two AVfistulas were successfully treated by manual compressionfor 20 min, and compression was guided and controlledby percutaneous color-coded duplex ultrasound. The fourhematomas did not require further treatment.

One hundred twelve transpopliteal interventions wereperformed (Table 2). The diameter of catheters and intro-ducer sheaths in the popliteal artery varied from 5 to 8 F(10 F in 1 patient with subsequent implantation of aCragg endoprosthesis). Eighty-nine of all 112 interven-tions (79.5%) were performed successfully by transpop-liteal approach alone. The intervention failed in 21 ex-aminations: the occlusion could not be passed due to cal-cifications in 15 cases, and a subintimal catheter passagehindered access of the proximal lumen in 6 cases. Twocases (1.8%) required additional transfemoral punctureto finish the intervention successfully: in the first case,the introducer sheath for the stent application was tooshort, and in the second case the passage of the occlusionwas possible only with a cross-over procedure. The over-all success of transpopliteal interventions therefore was91 of 112 (81.3%).

Table 3 presents the complications of the poplitealpuncture and the three complications of interventionalprocedures after successful puncture of the popliteal artery.

Table 1 Location of stenosesor occlusions of patients referred for intervention

Location N %

Iliac artery 12 10.3Common femoral artery 5 4.3Popliteal artery 1 0.9Occlusion at or near the ostium of the superficial femoral artery 98 84.5Total 116

Table 2 Transpopliteal interventions. PTA percutaneous translu-minal angioplasty

Intervention N

PTA alone 98PTA with stent applicationa 8PTA with local thrombolysis 4Local thrombolysis only 2Total 112

a Sixteen stents implanted: Palmaz stent; Wallstent; Cragg pros-thesis

1975

Fig. 2a, b Transpopliteal angioplasty. a Proximal occlu-sion of the superficial femoralartery (SFA). b After success-ful angioplasty of the proximalSFA, the transpopliteal catheteris visible

1976

Discussion

The popliteal puncture for transpopliteal therapy of pe-ripheral arterial occlusive disease may solve some of thelimitations of the more common antegrade femoral ap-proach, e.g., in patients with combined iliac and femorallesions or with occlusion of the origin of the SFA [1, 2],with a high takeoff or an occlusion of the origin of theSFA or in patients with very recent punctures in thegroin, with graft prosthesis or extreme obesity [3, 4, 5, 6,7, 8, 9], but has inherent risks. While some alternativesexist to circumvent some of the limitations of the con-ventional transfemoral approach (e.g., cross-over sheetsto allow more forward pressure to pass stenosis or occlu-sion) the Doppler-guided transpopliteal approach seemed– after the experience gained in our department – fastand safe in a way that made its use first choice in a por-tion of these patients.

The proximity of the popliteal artery and vein espe-cially at the level of the joint space [12] increases therisk of AV fistulas. As the popliteal vein overlays thepopliteal artery in the distal third of the normal anatomiccourse of the vessels [4, 12], the puncture of the popli-teal artery in the proximal part is therefore mandatory.Up to 14% AV fistulas [6] and 2–4% hematomas [3, 5,13] are reported in transpopliteal interventions. Minorcomplications include vascular spasms due to the smallcaliber of the vessel. The high risk of complications ledto the development of techniques for accurate localiza-tion of the popliteal vessels to avoid improper puncture.

The use of a Doppler ultrasound-guided vascular ac-cess needle (SMART) was first described for jugularvein cannulation [14], using a transducer-equipped nee-dle. In this study, results in terms of complication rateand technical success did not benefit significantly fromthe use of the SMART needle, but aberrant puncturescould be avoided. Subsequent studies evaluated the useof the SMART needle for punctures of the femoral artery

[15] or for arterial access in pediatric patients [16]. Theuse of this device facilitated required puncture and sub-jectively eased the vascular access. The use of a SMARTneedle markedly reduced frequency and size of hemato-ma by approximately 50% in femoral artery puncture[15]. The puncture of the popliteal artery with a Doppler-equipped SMART needle has been described previously[8, 17] for transpopliteal intervention and for microinva-sive endarterectomy [18], but it has not been evaluatedin a larger number of patients.

The initial technical success rate of 94.1% is in thescope of results previously reported [3, 5, 6]. The com-plication rate of 5.2% in our study is comparable withprior studies [2, 4, 5, 6, 13], where complication rates of4–14% are reported. The rate of AV fistulas in our study(2 of 115, 1.7%) is lower than that reported in other stud-ies (6–14%) [2, 6, 16], whereas fistulas were not seen inolder reports of the fluoroscopy technique [3, 5]. Al-though all patients were controlled immediately as wellas 24 h after the intervention clinically and by ausculta-tion, color-coded ultrasound was only performed if theformer examinations led to the suspicion of AV fistula;therefore, it cannot be excluded that clinically inapparentAV fistula had been overlooked. Hematomas developedin 3.5% of cases. This compares favorably with the datareported in the literature [2, 3, 5, 19].

The success rate in this study of transpopliteal inter-vention of 79.5% and overall success rate of 81.3% com-pares favorably with the previously reported 71–84%success rates [4, 5, 6] for transpopliteal interventions.Nevertheless, the success rate of our transpopliteal inter-ventions (PTA and stent applications) is below the num-bers reported for transfemoral interventions (80–90%primary technical success). This lower success rate iscaused by the negative selection bias of patients suitedfor transpopliteal intervention only, e.g., the size and localization of stenosis or occlusion as well as prior interventional and surgical therapy [2]. The scope of

Table 3 Complications of popliteal puncture and transpopliteal intervention

Complication N Complication Therapyrate (%)

PuncturesPerformed punctures 115Local hematoma 4 3.5 NoneArteriovenous fistula 2 1.7 One-time manual compression, control with

color-coded duplex sonographyOverall complication rate of punctures 6 of 115 5.2

InterventionsPerformed interventions 112Mild adverse reaction on contrast media 1 NoneArterial embolization into the anterior tibial artery 1 NoneBallon ruptured 1 Removal of the balloonOverall complication rate of interventions 3 of 112 2.7

1977

indications for the transpopliteal approach using theSMART needle, and the distribution of primary and sec-ondary transpopliteal approach are similar to the indica-tions previously described [2, 3, 5] using other tech-niques of popliteal puncture.

The use of the Doppler needle has to be comparedwith other methods for the localization of the poplitealartery. Both fluoroscopic localization [2, 3, 5, 6] and per-cutaneous Doppler sonography are well established [2, 4,16]. While fluoroscopy allows the real-time visualizationof popliteal artery, vein, and needle, it requires a secondvascular access in the groin. Furthermore, repositioningof the patient from supine to prone position and anothersterilization is required. The puncture of the popliteal artery under fluoroscopic guidance includes the risk ofexposure of the examiners' hands while accessing thepopliteal artery.

These disadvantages do not apply to the conventionaltranscutaneous Doppler localization, which may be per-formed with B-mode sonography with or without duplexencoding of the vessels [2] or with CW Doppler [4]. B-mode ultrasound allows for real-time visualization ofthe needle and the target vessel and eases the arterialpuncture. The real-time ultrasound guidance requires aB-mode ultrasound machine, necessitating additionalpreparation and space in the angiography room. Addi-tional time and preparation has to be provided to assureand maintain proper sterile conditions while using thetransducer. Percutaneous CW Doppler sonography forthe identification and marking of the anatomical courseof the vessel requires less preparation, but steering of theneedle is not possible.

The SMART needle technique for popliteal punctureled to results equal to or better than data reported previ-ously [2, 3, 5, 6]. The main advantage results from thecombination of safety comparable to established tech-niques for popliteal puncture and at the same time thesignificantly reduced level of effort, preparation, andskills required. The immediate feedback provided byreal-time guidance resulted in high acceptance of thismethod among the performing radiologists. While popli-teal punctures require a certain level of experience, the

SMART needle technique allowed popliteal interven-tions to be performed by a broader range of radiologists,some being in training.

The cost for one-time acquisition of approximately$1500 and running costs of $80–$150 (with or withoutresterilization) has to be compared with the cost of cath-eter, contrast media, and ultrasound machine if othertechniques are used. In our opinion, the benefit of a reli-able, fast, and safe routine access of the popliteal arterycompensates for the cost.

A limitation of the present study is the lack of a controlgroup treated by one of the established methods of popli-teal arterial access, fluoroscopy, and percutaneous Dopp-ler or duplex. But the advantages of the SMART needleseemed to justify the complete switch of methods in ourdepartment. As a consequence, success rate and complica-tion rate can only be compared with the literature.

Proximal lesions or occlusions arising at the origin ofthe superficial artery are considered to be more suitablefor surgery than for angioplasty [20], because of the lower initial technical success rate and the lower long-term patency as compared with surgery. All patientswere informed about these limitations of the procedurebut had chosen the interventional approach.

Conclusion

The Doppler-guided puncture of the popliteal artery is asimple and reliable method for transpopliteal approach invascular interventions. This technique avoids the inher-ently higher risk associated with blind transpoplitealpuncture. Compared with other methods of location ofthe popliteal vessels, the Doppler-guided puncture withthe SMART needle does not compromise sterility andcan easily be integrated in the usual workflow of an arte-rial puncture. As the transpopliteal puncture offers atherapeutic alternative in addition to vascular surgery forpatients with arterial occlusive disease, especially inthose with occluded origins of the SFA, the SMART needle technique may allow the more widespread use ofthe popliteal approach in the future.

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