The combination of surgical embolectomy and endovascular techniques may improve outcomes of patients with acute lower limb ischemia

Open ArchivePublished:December 16, 2013DOI:https://doi.org/10.1016/j.jvs.2013.09.016

      Objective

      Surgical arterial thromboembolectomy (TE) is an efficient treatment for acute arterial thromboemboli of lower limbs, especially if a single large artery is involved. Unfortunately, residual thrombus, propagation of thrombi, chronic atherosclerotic disease, and vessel injuries secondary to balloon catheter passage may limit the clinical success rate. Intraoperative angiography can identify any arterial imperfection after TE, which may be corrected simultaneously by endovascular techniques (so-called “hybrid procedures,” HP). The aim of this study is to compare outcomes of surgical TE vs HP in patients with acute lower limb ischemia (ALLI).

      Methods

      From 2006 to 2012, 322 patients with ALLI were admitted to our department. Patients received urgent surgical treatment using only a Fogarty balloon catheter (TE group = 112) or in conjunction with endovascular completion (HP group = 210). In-hospital complications, 30-day mortality, primary and secondary patency, reintervention rate, limb salvage, and overall survival rates were calculated using the Kaplan-Meier method and compared by log-rank test.

      Results

      HPs (n = 210) following surgical TE consisted of angioplasty (PTA) ± stenting in 90 cases, catheter-directed intra-arterial thrombolysis + PTA ± stenting in 24, thrombus fragmentation and aspiration by large guiding catheter + PTA ± stenting in 67, vacuum-based accelerated thromboaspiration by mechanical devices in 9, and primary covered stenting in 12. Estimated primary patency was 90.4% vs 70.4% at 2-year and 87.1% vs 66.3% at 5-year follow-up, respectively, for HP and TE patients (hazard ratio, 3.1; 95% confidence interval, 1.78-5.41; P < .01). A hazard ratio of 2.1 for limb salvage was noted for the HP group (95% confidence interval, 1.01-4.34; P = .03). Estimated freedom from reintervention at 1 year was 94.4% for HP vs 82.1% for TE patients, and 89% vs 73.7% at 5 years, respectively (P = .04).

      Conclusions

      HPs for ALLI may represent the tools that, when applied to specific clinical scenarios, hold the potential to reduce the morbidity previously associated with acute arterial occlusion.
      Surgical arterial thromboembolectomy (TE) using a Fogarty balloon catheter is an efficient treatment for acute arterial emboli of lower limbs, especially when a single large vessel is involved.
      • Fogarty T.
      Historical reflections on the management of acute limb ischemia.
      Despite this, the early clinical outcome still remains unsatisfactory in a number of cases.
      • Henke P.K.
      Contemporary management of acute limb ischemia: factors associated with amputation and in-hospital mortality.
      It has been well established that intraoperative angiography after TE may frequently detect arterial imperfections, such as incomplete restoration of perfusion in below-the-knee (BTK) arteries, propagation of thrombi, or presence of underlying steno-occlusive lesions,
      • Plecha F.R.
      • Pories W.J.
      Intraoperative angiography in the immediate assessment of arterial reconstruction.
      • White G.H.
      • White R.A.
      • Kopchok G.E.
      • Wilson S.E.
      Angioscopic thromboembolectomy: preliminary observations with a recent technique.
      which may be responsible for the early failure. Finally, even vessel injuries secondary to balloon catheter passage may limit the clinical success rate.
      An alterative to surgery, percutaneous catheter-directed thrombolysis (CDT), has been proposed. A systematic review of data from the randomized trials performed in the mid-1990s concluded that operative revascularization or CDT in patients with acute lower limb ischemia (ALLI) carries similar major amputation and mortality rates, although CDT was associated with higher rates of hemorrhage and stroke at 30 days and an increased risk of distal embolization.
      • Palfreyman S.J.
      • Booth A.
      • Michaels J.A.
      A systematic review of intra-arterial thrombolytic therapy for lower-limb ischaemia.
      Over the last decade, various additional percutaneous techniques have been proposed for the treatment of ALLI, including mechanical thrombolysis, thrombus fragmentation and intraluminal thromboaspiration, angioplasty, and covered stenting.
      The role of the combination of surgical embolectomy and endovascular techniques (so-called “hybrid procedures,” or HP) for treatment of patients presenting with ALLI has not been established yet. The aim of this study is to compare outcomes of surgical TE vs HP in patients with ALLI.

      Methods

       Patient selection

      From January 2006 to September 2012, all patients who presented at our department with acute rising of the symptomatology suggestive for ALLI (less than 14 days) were included in a dedicated database. Patients with acute ischemia due to graft occlusion were excluded from the study. Demographic and clinical data, as well as operative details, were prospectively collected, and retrospectively analyzed.
      On a total of 322 patients with ALLI, interrogation of the database on the type of treatment (surgery vs surgery + endovascular HP) identified two groups of patients (Fig 1): (1) group 1: patients who received urgent surgical treatment only by Fogarty catheter TE (TE group; n = 112) and (2) group 2: patients who received HP (HP group, n = 210). Table I shows baseline characteristics of patients.
      Figure thumbnail gr1
      Fig 1Flowchart of group allocation. ALLI, Acute lower leg ischemia; HP, hybrid procedure; TE, thromboembolectomy.
      Table IBaseline characteristics of patients
      CharacteristicGroup TE (n = 112)Group HP (n = 210)P value
      Mean age ± SD, years72.5 ± 10.373.3 ± 11.6.4
      Gender, male/female71/41121/89.3
      Current/former smokers, %49.153.8.49
      Medical history/concomitant conditions, %
       Ischemic cardiopathy25.027.5.5
       Cerebrovascular disease13.414.7.5
       Atrial fibrillation/arrhythmias53.639.1.01
       Chronic peripheral arterial disease17.826.2.09
       Previous revascularization lower limb(s)16.920.4.3
       Hypertension61.659.0.3
       Diabetes21.420.4.3
      Duration of symptoms, %
       0-6 hours16.912.4.1
       6-24 hours29.531.4.4
       >24 hours53.656.2.4
      Clinical category of acute ischemia, %
       Class I2.72.6
       Class IIa44.648.1.5
       Class IIb39.335.2.3
       Class III13.414.7.8
      HP, Hybrid procedure; SD, standard deviation; TE, thromboembolectomy.

       Surgical strategy

      When a diagnosis of ALLI is confirmed by clinical examination and duplex ultrasound performed by the on-call vascular surgeon, our protocol includes the immediate infusion of continuous intravenous heparin sodium (≈20,000-40,000 units/24 hours in 50 mL of saline injection) to limit the propagation of thrombus and prevent clinical deterioration. The dosage of heparin is adjusted according to the patient's coagulation test results, considering adequate an activated partial thromboplastin time of 2 to 2.5 times the control value.
      Surgical intervention is immediately planned and performed as soon as possible according to the availability of an operating theater.
      Most of our patients are approached through a common or superficial femoral artery (SFA) exposure, which permits access for a balloon catheter TE from the aortic bifurcation to the ankle. Occasionally, below-knee trifurcation arterial exposure with tibial-peroneal arterial TE may be required.
      A bolus of 5000 UI of heparin sodium is administered intravenously, just before arteriotomy and TE by Fogarty balloon catheter of a diameter well matched to the target artery (range, 2-5 F).
      After TE, all patients receive intraoperative assessment of the adequacy of clot removal by physical examination (presence of femoral, popliteal, and tibial pulses), by continuous wave (CW) Doppler evaluating the flow of the peroneal, posterior, and anterior tibial arteries at ankle level, and, selectively, by completion angiography. The decision to perform an on-table angiography is based on several factors, mainly the following four: (1) the absence of satisfactory back-bleeding from distal vessels; (2) the demonstration of signals of poor revascularization by the CW Doppler at the ankle; (3) the poor clinical appearance of the foot; (4) the impossibility to advance the Fogarty catheter far enough distally.
      Angiography is generally performed by direct puncture of the exposed artery, or, in case of BTK arterial exposure, by puncture of the ipsilateral common femoral artery.
      When the angiography diagnoses an incomplete restoration of perfusion, then different endovascular options are evaluated based on the location and length of residual clot.
      A catheter-directed intra-arterial thrombolytic therapy using a multisided port catheter passed through the residual thrombus is preferred when the amount of residual thrombus is longer than 15 cm. In such cases, after delivering a single ranging 3- to 5-mg dose of recombinant tissue-type plasminogen activator (Alteplase) throughout the occlusion, a continuous infusion for 24 hours is continued at 0.5 to 1.0 mg/kg/h (20 mg maximum). The thrombolytic catheter is generally placed through the open incision, although we prefer first to suture the arteriotomy used for the TE, and then we puncture the exposed artery at a different point and insert the thrombolytic catheter. A concomitant low-dose of heparin (300 to 500 units per hour) is typically infused through the arterial access sheath to prevent thrombosis around the sheath. A completion angiography is performed after 24 hours.
      Distinctive percutaneous options are evaluated in cases of residual thrombosis <15 cm in length. These include mechanical thrombectomy techniques, which are finalized to clear the remaining intravascular thrombus by thrombus fragmentation and aspiration, and vacuum-based accelerated thromboaspiration and lysis.
      When the completion angiography reveals the presence of an underlying atherosclerotic steno-occlusive lesion after clot removal, a plain balloon angioplasty (PTA) is performed, and a nitinol stent is implanted in case of residual stenosis >30% or flow-limiting dissections (bailout stenting). Primary covered stenting is also considered in cases of persistent partial intraluminal thrombosis adherent to the arterial wall after TE.
      Standard anticoagulation with intravenous heparin is generally applied in the early postoperative period. In all patients with atrial fibrillation or in the presence of other cardiac sources of emboli, prosthetic cardiac valves, or a known hypercoagulable state, warfarin anticoagulation is initiated some days after intervention with a long-term target international normalized ratio of 2 to 3.
      Remaining patients, or those with contraindications to warfarin anticoagulation, receive an antiplatelet agent (clopidogrel 75 mg/day or aspirin 100 mg/day or ticlopidine 250 mg twice a day) henceforth. A 1-month dual antiplatelet therapy (clopidogrel 75 mg/day + aspirin 100 mg/day) is also suggested in cases of stent deployment.

       Follow-up protocol

      An ultrasound examination is performed within 48 hours of revascularization and repeated at day 30, at 3, 6, 9, and 12 months, and then yearly. The clinical status of the patients and duplex-ultrasound is evaluated at the same intervals. The ultrasound examination measures the patency of the treated arteries and any evidence of internal thrombus. All examinations are performed in the same vascular laboratory, using the same ultrasound machines (Ultramark IU-22 and HDI 3500 ATL-Philips, Eindhoven, Holland). The B-mode imaging frequency is 7 MHz, and the pulsed-wave Doppler frequency is 4 MHz.
      The criteria for reintervention during follow-up are based on clinical symptoms (clinically driven revascularization). Repeat percutaneous or surgical interventions are planned only in case of the presence of rest pain, ischemic lesions (primary ulcer or nonhealing ulcer), or disabling intermittent claudication, while asymptomatic partial or complete reocclusions of the previously treated arterial segment are managed conservatively.

       Definitions and end points

      Clinical outcomes, primary patency, secondary patency, and complications following revascularization were reported according to the “Recommended standards for reports” by Rutherford et al.
      • Rutherford R.B.
      • Baker J.D.
      • Ernst C.
      • Johnston K.W.
      • Porter J.M.
      • Ahn S.
      • et al.
      Recommended standards for reports dealing with lower extremity ischemia: revised version.
      Primary technical success of HP was defined as continuous arterial patency of at least one artery to the foot without any obvious flow-limiting lesions (absence of a stenosis >50%). Patency of the peroneal artery with good collateral flow to the dorsalis pedis artery or to the plantar arteries was also considered a primary technical success.
      Limb salvage was defined as no amputation proximal to the metatarsus.
      In-hospital complications, 30-day mortality, primary and secondary patency, freedom from reintervention, freedom from amputation, and overall survival rates were calculated for the two study groups.

       Statistical analysis

      The data were expressed as mean and standard deviation or as median and interquartile range, depending on the type of distribution. All results were analyzed using MedCalc version 12.5.0.0 (MedCalc Software bvba, Ostend, Belgium). Comparison of baseline characteristics between treatment groups was calculated by t-test or χ2 test, as appropriate.
      Kaplan-Meier curves were used to calculate the survival, primary and secondary patency, freedom from reintervention, and limb salvage rates. Log-rank test was used for the comparison between the survival curves of the two study groups. If the P value associated with the χ2 statistic was small (<.05), then the conclusion was that, statistically, the two survival curves differ significantly, or that the grouping variable (ie, type of intervention: TE vs HP) had a significant influence on survival time.
      • Altman D.G.
      • De Stavola B.L.
      Practical problems in fitting a proportional hazards model to data with updated measurements of the covariates.
      The hazard ratio (HR) with its 95% confidence interval (CI) was also calculated.

      Results

      All patients underwent surgical revascularization by TE as first-line treatment. Location of surgical cutdown is summarized in Table II. In some patients, a combined exposure of the common femoral artery and distal popliteal artery was necessary.
      Table IILocation of surgical cutdown
      CutdownTE group (n = 112), No. (%)HP group (n = 210), No. (%)
      CFA51 (45.5)86 (40.9)
      SFA30 (26.8)53 (25.2)
      BK popliteal14 (12.5)33 (15.7)
      CFA + BK popliteal11 (9.8)22 (10.4)
      SFA + BK popliteal6 (5.3)16 (7.6)
      BK popliteal, Below-the-knee popliteal artery; CFA, common femoral artery; HP, hybrid procedure; SFA, superficial femoral artery; TE, thromboembolectomy.
      On the basis of intraoperative findings, an on-table angiography was performed in 242 out of 322 patients (Fig 1). The angiography confirmed the need of further endovascular treatment in 210 cases (HP group). Indications to proceed with endovascular revascularization were the presence of: (1) chronic atherosclerotic disease at SFA or BTK vessels considered responsible for the acute thrombosis (so-called “stenosis underlying the thrombosis”) in 90 cases; (2) incomplete recanalization due to residual thrombus in SFA and popliteal firmly adherent to the arterial wall in 54 cases; (3) residual thrombus in BTK vessels, which have not been appropriately reached by the balloon catheter TE, in 58 cases; (4) iatrogenic lesions of the arterial wall secondary to the intraluminal passage of the Fogarty balloon catheter in eight cases (intimal flap, n = 5; perforation, n = 1; post-traumatic aneurysm, n = 1; Fig 2).
      Figure thumbnail gr2
      Fig 2Findings at intraoperative angiography after thromboembolectomy (TE) in the hybrid procedure (HP) group. BTK, Below-the-knee; SFA, superficial femoral artery.
      For the purpose of this analysis, the TE group (n = 112) included patients treated only by Fogarty balloon TE (n = 80) and patients with no need of further treatment at intraoperative angiography (n = 32; Fig 1).
      The two groups of analysis were similar in terms of gender, median age, and risk factors, except for the incidence of atrial fibrillation or arrhythmia, that was statistically higher in the TE group (53.6% vs 39.1%; P = .01). A nonsignificant statistical trend was also noted for the rate of previous peripheral arterial disease (defined as history of intermittent claudication, rest pain, or ulcer) in HP patients (17.8% vs 26.2; P = .09; Table I).
      Different endovascular options were offered to patients with positive findings at intraoperative angiography. In the presence of chronic atherosclerotic disease of native arteries underlying the thrombosis (n = 90), a PTA was performed, followed by nitinol stent implantation in 31 cases (Table III).
      Table IIIDetails of surgical and endovascular procedures in the hybrid procedure (HP) group
      Open surgeryFindings at intraoperative angiographyEndovascular solution adoptedLevelAdjuvant procedure
      TENative arterial lesions (stenosis underlying the thrombosis)

      n = 90
      PTA (n = 59);

      PTA + stenting (n = 31)
      SFA (n = 54);

      Popliteal (n = 2);

      BTK (n = 21);

      SFA and BTK (n = 13)
      None
      TEResidual thrombus (>15 cm in length)

      n = 24
      Catheter-directed intra-arterial thrombolysis (n = 24)SFA (n = 2);

      BTK (n = 9);

      SFA popliteal and BTK (n = 8);

      Popliteal and BTK (n = 5)
      Thromboaspiration

      (n = 5);

      PTA (n = 11);

      PTA + stenting (n = 3)
      TEResidual thrombus (<15 cm in length)

      n = 76
      Thrombus fragmentation and aspiration by large guiding catheter (n = 67)SFA (n = 11);

      Popliteal (n = 7);

      BTK (n = 21);

      SFA popliteal and BTK (n = 13);

      Popliteal and BTK (n = 15)
      PTA (n = 41);

      PTA + stenting (n = 5)
      Vacuum-based accelerated thromboaspiration by mechanical devices (n = 9)SFA (n = 1);

      BTK (n = 6);

      Popliteal and BTK (n = 2)
      PTA (n = 3);

      PTA + stenting (n = 1);

      pulse spray thrombolysis (n = 5)
      TEIncomplete luminal thrombosis

      n = 12
      Primary covered stenting (n = 12)SFA (n = 11);

      Popliteal (n = 1)
      None
      TEVessel injury after Fogarty catheter passage

      n = 8
      Prolonged PTA (n = 5) + additional stenting (n = 3)SFA (n = 2);

      Popliteal (n = 1);

      BTK (n = 5)
      None
      BTK, Below-the-knee vessels; PTA, percutaneous transluminal angioplasty; SFA, superficial femoral artery; TE, thromboembolectomy.
      A catheter-directed intra-arterial thrombolytic therapy was performed in 24 cases, due to the evidence of a large amount of residual thrombosis (>15 cm in length) at intraoperative angiography. The angiography after 24 hours showed the presence of lesions requiring further endovascular treatment in 14 cases (PTA, n = 11; stenting, n = 3).
      Alternative endovascular solutions in cases of residual thrombosis <15 cm in length were thrombus fragmentation and aspiration by a large guiding catheter in 67 cases and vacuum-based accelerated thromboaspiration by mechanical devices (AngioJet Ultra Thrombectomy System; Medrad, Inc, Warrendale, Pa; standard and power-pulse spray technique) in nine cases. Thrombo-aspiration was followed by PTA ± stenting in the majority of cases (Table III).
      Primary covered stenting was also considered in cases of incomplete luminal thrombosis (n = 12).
      Vessel injuries after TE were fixed by prolonged PTA (n = 5) and additional stenting (n = 3).
      Primary technical success of HP was 99.1%.
      No intraoperative deaths occurred. The mortality rate at 30 days was 3.7% (12 of 322), due to myocardial infarction (n = 4), acute renal failure (n = 2), congestive heart failure (n = 4), or multiorgan failure syndrome (n = 2). In-hospital complications occurred in 17 patients in group TE and 29 patients in group HP (P = .07). The incidence of cardiac complications was higher in the TE group (P = .04), while hematoma at level of surgical cutdown was more frequent in the HP group (P = .05; Table IV).
      Table IVEarly complications
      TE group (n = 112), No. (%)HP group (n = 210), No. (%)P
      30-day mortality5 (4.4)7 (3.3).5
      In-hospital complications17 (15.1)29 (13.8).7
       Cardiac (myocardial infarction, congestive heart failure)78.4
       Neurological (stroke)231
       Renal331
       Pulmonary251
       Hematoma at level of surgical cutdown310.5
      HP, Hybrid procedure; TE, thromboembolectomy.
      The mean length of follow-up was 989 ± 52 days (range, 30-2175 days), and 27 patients were lost to follow-up during the study period. Fig 3, Fig 4, Fig 5, Fig 6 show the Kaplan-Meier curves of survival, primary and secondary patency, and limb salvage rates for the two study groups. Cumulative survival rate at 5 years was 82.8% (no statistical difference between the two study groups). The primary patency was 92.4% vs 77.5% at 1-year, 90.4% vs 70.4% at 2-year, and 87.1% vs 66.3% at 5-year follow-up, respectively, for HP and TE patients (HR, 3.1; 95% CI, 1.78-5.41; P < .01; Fig 4). Secondary patency at 2 years in HP patients was 97.8% in HP patients vs 90.1% in TE patients (HR, 3.9; 95% CI, 1.41-10.90; P < .01; Fig 5).
      Figure thumbnail gr3
      Fig 3Survival curves. CI, Confidence interval; DF, degrees of freedom; HP, hybrid procedure; TE, thromboembolectomy.
      Figure thumbnail gr4
      Fig 4Primary patency curves. CI, Confidence interval; DF, degrees of freedom; HP, hybrid procedure; TE, thromboembolectomy.
      Figure thumbnail gr5
      Fig 5Secondary patency curves. CI, Confidence interval; DF, degrees of freedom; HP, hybrid procedure; TE, thromboembolectomy.
      Figure thumbnail gr6
      Fig 6Limb salvage curves. CI, Confidence interval; DF, degrees of freedom; HP, hybrid procedure; TE, thromboembolectomy.
      An HR of 2.1 for limb salvage was noted for the HP group (95% CI, 1.01-4.34; P = .03; Fig 6).
      Estimated freedom from reintervention at 1 year was 94.4% for HP vs 82.1% for TE patients and 89% vs 73.7% at 5 years, respectively (P = .04; Fig 7). The reinterventions performed were either redo surgery (TE by Fogarty's catheter, n = 8; bypass surgery, n = 11), endovascular (PTA ± stenting, n = 6; CDT, n = 8), or hybrid intervention (n = 12).
      Figure thumbnail gr7
      Fig 7Freedom from reintervention curves. CI, Confidence interval; DF, degrees of freedom; HP, hybrid procedure; TE, thromboembolectomy.

      Discussion

      While improvements in surgical techniques and perioperative patient care have occurred over the years, the results available document a persistently high medical need for patients presenting with ALLI, with a reported 30-day amputation rate of 5% to 12%, mortality risk of 10% to 38%, and combined incidence of amputation and death of 25% to 37.5% at 6-month follow-up.
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      • Pemberton M.
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      • Bell P.R.
      The surgical management of acute limb ischaemia due to native vessel occlusion.
      In clinical practice, there is a discrepancy between the immediate technical success of arterial TE that often seems adequate, and the early clinical outcome that still remains unsatisfactory in a number of cases. This incongruence may be related to the incomplete restoration of perfusion due to residual thrombus in distal vessels inaccessible to the balloon embolectomy or to the propagation of residual thrombi. Both historical experimental and clinical studies have shown that clot removal is frequently incomplete after TE, with persistent thrombus demonstrated angiographically and by fiber optic angioscopy in small distal vessels in 36% to 82% of patients.
      • Plecha F.R.
      • Pories W.J.
      Intraoperative angiography in the immediate assessment of arterial reconstruction.
      • White G.H.
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      • Wilson S.E.
      Angioscopic thromboembolectomy: preliminary observations with a recent technique.
      Our study confirms that, when an adequate intraoperative angiogram after TE is performed, the detection of imperfect revascularization needing treatment is very high (86%; 210 HPs out of 242 on-table angiographies).
      The first attempt to improve the surgical technique for treating acute arterial occlusion was described by Parsons et al in 1996.
      • Parsons R.E.
      • Marin M.L.
      • Veith F.J.
      • Sanchez L.A.
      • Lyòn R.T.
      • Suggs W.D.
      • et al.
      Fluoroscopically assisted thromboembolectomy: an improved method for treating acute arterial occlusions.
      Suggesting the use of intraoperative fluoroscopy and the performance of fluoroscopically assisted TE, the authors described the first example of combination of surgical and endovascular technique for treatment of ALLI. This original HP turned out to improve the technical success of TE. Facilitating the catheter passage through tortuous or diseased arteries, this new technique minimized arterial damage and blood loss during clot removal. It had also the potential to facilitate accurate identification, localization, and treatment of significant concomitant arterial lesions.
      Since then, it has been recommended to perform a routine angiography after TE,
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      Our experience confirms the central role of intraoperative angiography after TE in defining the need for as well as guiding adjunctive endovascular procedures, which are the keys for better early and midterm outcomes of ALLI patients. If a surgical strategy with on-table angiography in all cases is not possible, at least it should be advocated every time a BTK intervention is done.
      CDT has been used as an alternative to surgical embolectomy for ALLI with gratifying results, but its success is related to the ability to pass a guide through and embed a multisided catheter into the occlusion.
      • Berridge D.C.
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      • The STILE Investigators
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      Results from randomized trials comparing the two treatments reveal that thrombolysis has the greatest advantage in acute prosthetic bypass graft occlusions, while patients with ALLI due to native arterial occlusions tend to be associated with inferior results after thrombolysis, consisting in higher rates of hemorrhage and stroke at 30 days, and increased risks of distal embolization.
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      • Sussman B.
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      These data have influenced our clinical protocol in the management of ALLI patients. In our center, a first-line treatment by CDT is reserved for ALLI due to bypass graft thrombosis, while operative revascularization is generally the preferred initial option for patients with native arterial occlusions. Our experience showed that completion angiography after TE can not only identify residual thrombus in distal vessels but also incomplete recanalization of more proximal arteries due to residual thrombus strongly adherent to the arterial wall, or can reveal the presence of significant underlying steno-occlusive lesions after clot removal. In a limited number of cases (3.3%), angiography can even demonstrate the existence of vessel injuries secondary to incorrect balloon catheter passage. These points clearly call for a routine and accurate intraoperative assessment of the adequacy of clot removal, which may be performed by angiography, angioscopy, or intravascular ultrasound.
      It has been a common belief in the past to rely on the presence or absence of back-bleeding from a peripheral arterial bed as a guide to distal arterial patency. Actually, we know that visual evaluation of outflow may be ambiguous to truly prove that adequate circulation has been restored, since irregular thrombotic material may be present in approximately one-third of cases,
      • Pemberton M.
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      • Bell P.R.
      The surgical management of acute limb ischaemia due to native vessel occlusion.
      and back-bleeding may be quite misleading in cases of adequate collateral circulation, despite the occurrence of total distal obstruction.
      Percutaneous mechanical thrombectomy devices have been proposed over the past decade to speed up the time required for dissolution of thrombus by pharmacologic means and to reduce the amount of thrombolytic agent used.
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      Treatment of acute limb ischemia with focus on endovascular techniques.
      These devices have been developed for aspiration and dissolution of small amounts of thrombotic material during coronary procedures, while the clot quantity in cases of ALLI may be much larger, resulting in 25% to 30% inadequate clot removal in patients presented with occlusion of native vessels or grafts.
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      Moreover, large particulate debris and microembolization has been described with all-mechanical thrombectomy, as well as the inability to completely remove huge and well-organized thrombi when densely adherent to the arterial wall.
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      • Erbel R.
      • et al.
      A new thrombectomy catheter device (AngioJet) for the disruption of thrombi: an in vitro study.
      • Krueger K.
      • Deissler P.
      • Coburger S.
      • Fries J.W.
      • Lackner K.
      How thrombus model impacts the in vitro study of interventional thrombectomy procedures.
      Additionally, the rapid stream of fluid and hydrodynamic forces used by thrombectomy devices may cause a significant amount of red blood cell hemolysis resulting in hemoglobinemia and hemoglobinuria. This may occur when repeated passes of the device are required, resulting in severe consequences, mainly in patients with renal insufficiency.
      • Rogers J.H.
      • Laird J.R.
      Overview of new technologies for lower extremity revascularization.
      Consequently, we believe that surgical TE is still the most effective and less time-consuming solution in removing a large clot from the femoropopliteal arterial segment.
      Percutaneous pharmacological or mechanical thrombolysis, applied as an adjuvant procedure to surgery, may improve results by clearing a reasonable amount of clot from distal vessels, with remarkable primary technical success (99.1%).
      Patients treated by HP had better primary and secondary patency rates as well as lower reintervention rates, which were already evident at 1-year, and were confirmed at 3- and 5-year analysis. As a result, HP patients had an individual clinical benefit consisting in improved limb salvage rate from the 3rd year onward (Fig 6).

       Limitations

      A limitation of the present study is that completion angiography was performed selectively, based on subjective and independent parameters. This may have introduced bias in favor of HP.

      Conclusions

      Some kind of intraoperative imaging study is advisable because of a high incidence of underlying lesions that can cause acute arterial occlusion. The combination of surgical and endovascular options, appropriately selected on the angiographic findings after TE, may overcome the limitations that characterize the traditional approach in patients with ALLI. HPs may represent the tools that, when applied to specific clinical scenarios, hold the potential to reduce the morbidity previously associated with acute arterial occlusion and improve early and midterm clinical outcomes.

      Author contributions

      Conception and design: GdD, CS
      Analysis and interpretation: GdD
      Data collection: FS, PS, GG, RM
      Writing the article: GdD
      Critical revision of the article: GdD, FS, CS
      Final approval of the article: GdD, FS, CS
      Statistical analysis: GdD, PS, GG
      Obtained funding: Not applicable
      Overall responsibility: GdD, CS

      Supplementary data

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