Abstract
Background
The use of Directional Atherectomy (DA) for the treatment of calcified femoro-popliteal lesions seems to improve the acute procedural success, however without reducing the long term restenosis rate. Drug coated balloons (DCB) reduced restenosis rate in non heavy calcified lesions. Aim of this study was to demonstrate safety and efficacy of a combined endovascular approach using DA and DCB for the treatment of heavy calcified lesions of the femoro-popliteal tract.
Methods: From January 2010 to November 2010, 240 patients underwent PTA of the femoro-popliteal tract in our institution. Within this cohort a total of 30 patients had Life Limiting Claudication (LLC) (n = 18) and 12 a Critical Limb Ischemia (CLI) with baseline Rutherford class 4.2 ± 1.2 underwent PTA of heavy calcified lesions with intravascular ultrasound guided DA and DCB. All procedures have been performed using a distal protection device. Stent implantation was allowed only in case of flow limiting dissections or suboptimal result (residual stenosis > 50%) by visual estimation. After the intervention patients were followed up to 12 months.
Results
Procedural and clinical success, was achieved in all cases. Bail-out stenting was necessary in only two (6.5%). At twelve month follow up median Rutherford class was 2.2 ± 1.2, ABI was 0.8 ± 0.1 and Limb salvage rate was 100%. Two minor, foot finger or forefoot amputations, were performed to reach complete wound healing and/or preserve deambulation. Duplex control was performed in all the cases (n = 30). In three cases duplex scan showed a significant target lesion restenosis requiring a reintervention (TLR = 10%) leading a total one-year secondary patency rate of 100%. All the three restenosed patients were insulin dependent diabetics and none of them were stented during the procedure.
Conclusion
The data suggest that combined use of DA and DCB may represent a potential alternative strategy for the treatment of femoro-popliteal severely calcified lesions. These very promising data and the considered hypothesis have to be confirmed in a multicentre randomised trial.
1
Introduction
Restenosis rate after percutaneous transluminal angioplasty (PTA) of calcified superficial femoral and popliteal artery is still the “Achilles’ Hill” of this endovascular procedure .
One of the most important limiting factors in terms of acute procedural success rate and need of stent implantation, as well as long term patency seems to be the presence of diffuse and severe calcification of the target lesion.
Moreover the majority of randomised controlled studies considered severe calcification of the lesion as an exclusion criterion. The presence of severe calcification of the atherosclerotic lesion is responsible for a poor response to balloon dilation, due to significant acute vessel recoil and frequent flow limiting dissections. Directional atherectomy (DA) improves acute success by Debulking fibrocalcific portion of the atherosclerotic plaque , but does not provide any benefits in terms of patency rate .
The use of drug coated balloons (DCB) for the endovascular treatment of the femoro-popliteal tract has been demonstrated to reduce the occurrence of restenosis . There are no data available, at the moment, regarding the use of DCB in heavy calcified lesions.
In this registry we applied a new endovascular approach for the treatment of severely calcified lesions in the femoro-popliteal tract, based on the combination of DA followed by DCB, to prevent long-term restenosis and to reduce the need of stenting.
2
Methods
2.1
Study design
This is a single centre, single arm, perspective non randomised study.
2.2
Study population
From January 2010 to November 2010, 240 patients underwent percutaneous transluminal interventions (PTA) of the femoro-popliteal artery in our institution due to critical limb ischemia (CLI) or life limiting claudication (LLC).
Within this cohort, 30 patients, 18 with LLC and 12 with CLI, underwent PTA of heavy calcified (calcium score > 3) type A–C lesion according to the TASC II recommendation . Four lesions were total occlusions. Calcifications were detected both with duplex scan according to “vessel compressible concept” meaning the absence of any calcification and with fluoroscopy: grade 0 = absence of any evidence of calcifications; grade 1 = calcifications at one side of lumen with length < 1 cm; grade 2 = calcifications at both sides of lumen < 1 cm; grade 3 = calcifications at both sides of lumen > 1 cm in length ( Fig. 1 ). The main lesion-specific inclusion criteria were a vessel diameter of 3.0 to 5.0 mm and a maximum lesion length of 15 cm in the femoro-popliteal segment. The exclusion criteria were: angiographic evidence of fresh thrombus presence, lesion length > 15 cm or type D lesion according to the TASC II recommendation, generally considered an elective indication for surgical treatment, in stent restenosis, absence of severe heavy calcification. Endovascular treatment included the combined use of the directional atherectomy (Turbo Hawk Plaque Excision System-Covidien, USA) and a Paclitaxel coated balloon (Admiral In-Pact; Medtronic, USA).
2.3
Concomitant therapy
All patients received aspirin (75–160 mg/day) and should have been on ticlopidine (250 mg twice daily) for at least 7 days. Alternatively patients received clopidogrel preload (300 mg) 24 h before procedure. Post procedure, thienopyridines were continued for 30 days, whereas aspirin was continued for life.
For anticoagulation, 70–100 IU/kg of heparin was administered before wiring the lesion, with intention to achieve an ACT > 250 s. Additional heparin was administered at operator discretion according to ACT values (2).
2.4
PTA Technique
All procedures were performed percutaneously, with the patient under local anesthesia. Vascular access was achieved via contralateral common femoral artery. A 55 cm 8 Fr (COOK inc. USA) long sheath was used in order to achieve adequate support and to allow continued flushing with saline and/or contrast medium injection while using TurboHawk.
Once diagnostic angiography was completed, a wire (0.014”), chosen by the operator according to the stenosis type was navigated in the distal popliteal artery. In the case of total occlusion, 0.018 or 0.35” was used to cross the lesion and then was replaced by a 0.014” wire. Balloon predilation was used only in case of total occlusion (n = 4) with undersized balloon just to allow filter and Turbo-Hawk getting through the lesion. In the case of total occlusion a 0.018” wire (n = 1) or 0.035” stiff wire (n = 3) was used to cross the lesion and then was replaced by a 0.014” one. All recanalizations were done with intraluminal technique. In order to avoid embolization of atherosclerotic Debris a filter for distal protection (Spider FX – EV3) was placed distal to the stenosis prior to the use of peripheral directional atherectomy. This kind of filter-wire was used mainly for the following reason: this device is wire-independent and allows to use an independent wire to cross the lesion/occlusion.
After filter placement DA was performed. When the atherectomy device nose was filled, it had to be removed and the atherosclerotic plaque removed from the storage nose cone. Number of cutting passages was decided only by the operator. Each time, according to the operator filing, TurboHawk was pulled back to perform angiographic and IVUS check of the lesion. None of TurboHawk system was blocked by calcified Debris needing use of an additional device. When angiograms and IVUS demonstrated that residual stenosis was lower than 30% a post dilation with DCB (sizing was 1:1 to the reference vessel diameter and 10 mm longer than stenosis) for at least 180 s was performed. The DCB device used was the IN.PACT ADMIRAL PTA Balloon (Medtronic – USA). This is a 0.035” peripheral balloon catheter coated with a matrix consisting of drug (paclitaxel) combined with a hydrophilic spacer (Urea). All these components work when the balloon contacts the vessel wall and the drug is freed, then pressed into the vessel wall; this allows for an effective transfer controlled by how drug is loaded on balloon and inhibit tissue growth within the artery, a factor that leads to the re-narrowing of arteries.
At this point IVUS was used to confirm the presence of a residual stenosis less than 30% and to confirm the absence of flow limiting dissections with Chroma-Flow application ( Figs. 1, 2 ). Stent implantation was allowed, by protocol, for bail-out stenting: flow limiting dissection persisting after prolonged balloon dilatations, residual stenosis > 50% by visual estimation.
2.5
Post procedural patient management
Femoral sheaths were removed when ACT was < 150 s. Access site haemostasis was achieved by manual compression in all patients.
If clinical signs of limb ischemia occurred on the side of femoral access, sheaths were removed independently of post procedural time and ACT values. Femoral sheath induced leg ischemia was classified as major if it required thromboembolectomy and minor if it was resolved by sheath removal.
A complete blood count was obtained before procedure and prior to hospital discharge.
2.6
Patients follow up
Patients were evaluated through hospital discharge, at 30 days, and at 3, 6 and 12 months post procedure. The pre-interventional workup and the follow-up visits at each interval included physical and clinical examination, assignment of a Rutherford classification, arterial Doppler occlusion pressure measurements with calculation of the ankle–brachial index (ABI), and color duplex sonography measuring peak systolic velocities (PSV) for the calculation of the proximal peak systolic velocity ratio (PFVR).
2.7
Definitions
Procedural time was defined as the time lasting from the completion of diagnostic angiography and final views.
Technical Success was defined as the ability to pass the lesion with guide wire and to successfully perform DA and DCB postdilation with a residual stenosis < 30%.
Procedural Success was defined as technical success without the occurrence of any Major Adverse Events (MAE).
2.8
Endpoints
The primary safety endpoint was the freedom from major adverse events (MAE) including clinically driven target lesion revascularization (TLR), any death, target vessel revascularization (TVR), myocardial infarction (MI), and index limb amputation at one year post procedure. The primary efficacy endpoint was the one year Primary Patency: freedom from target lesion revascularization.
TLR could be performed when arterial duplex evaluation of the proximal flow velocity was between 2.5 and 5.0 (intermediate restenosis) and patient had clinical symptoms or when PFVR was greater than 5.0 (severe restenosis) regardless of the presence of clinical symptoms.
The secondary endpoints included (1) Secondary patency at one year documented by duplex ultrasound (patency defined as a proximal flow velocity ratio < 2.5), (2) reduction in post-dilatation flow limiting dissection, (3) clinical success as defined by > 1 clinical category improvement in the Rutherford scale (or equivalent) from baseline (or 2 categories if there was pre- existing tissue loss) at one year, and (4) hemodynamic success, defined by a 0.1 improvement in the ABI during the period from baseline to 30 days post procedure and no deterioration > 0.15 from the maximum early post procedure level at one year.
2.9
Statistics
Nominal and categorical variables were presented as contingency tables with frequencies and percentages. Continuous variables were reported as the mean with standard deviation and compared by t test for normally distributed values (probability value <.05 was considered statistically significant).
2
Methods
2.1
Study design
This is a single centre, single arm, perspective non randomised study.
2.2
Study population
From January 2010 to November 2010, 240 patients underwent percutaneous transluminal interventions (PTA) of the femoro-popliteal artery in our institution due to critical limb ischemia (CLI) or life limiting claudication (LLC).
Within this cohort, 30 patients, 18 with LLC and 12 with CLI, underwent PTA of heavy calcified (calcium score > 3) type A–C lesion according to the TASC II recommendation . Four lesions were total occlusions. Calcifications were detected both with duplex scan according to “vessel compressible concept” meaning the absence of any calcification and with fluoroscopy: grade 0 = absence of any evidence of calcifications; grade 1 = calcifications at one side of lumen with length < 1 cm; grade 2 = calcifications at both sides of lumen < 1 cm; grade 3 = calcifications at both sides of lumen > 1 cm in length ( Fig. 1 ). The main lesion-specific inclusion criteria were a vessel diameter of 3.0 to 5.0 mm and a maximum lesion length of 15 cm in the femoro-popliteal segment. The exclusion criteria were: angiographic evidence of fresh thrombus presence, lesion length > 15 cm or type D lesion according to the TASC II recommendation, generally considered an elective indication for surgical treatment, in stent restenosis, absence of severe heavy calcification. Endovascular treatment included the combined use of the directional atherectomy (Turbo Hawk Plaque Excision System-Covidien, USA) and a Paclitaxel coated balloon (Admiral In-Pact; Medtronic, USA).
