Endovascular surgery

Endovascular surgeryPresenter: Dr Anil MeeteiModerator: Dr Th ChitoAsst prof, CTVS

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Endovascular surgeryEndovascular surgery is a form of minimally invasive surgery/procedures for imaging the circulation or for treating vascular disorders from within the circulation, through catheters/miniature instruments inserted percutaneously into the blood vessels

Scope of endovascular therapyBaloon angioplastyEndovascular cryotherapyStentingAngioscopy /intravascular ultrasoundAtherectomyThromb0embolectomy /intraarterial thrombolysisEmbolizationEndovascular aneurysm repair (EVAR)Endovenous laser ablation (EVLA)Endovascular RFATranscatheter aortic valve implantation (TAVI)Percutaneous mitral valve repair

Basic instrumentsNeedlesGuidewires CathetersSheaths

Endovascular device sizingDEVICEMEASUREMENTUNITEntry needleouter diametergaugeGuide wireouter diameterinchSheath inner diameterfrenchGuiding outer diameterfrench catheterdiagnostic outer diameterfrench catheter

Common interventionsBalloonsStentsStent graftsFiltersThrombolyticsClosure devicesIVUS

Contrast mediaIonicNon ionic

Contrast agentsIso osmolar-iodixanol, iotrolan(non ionic)Low osmolarIonic dimer-meglumine ioxaglateNon ionic monomer- iopamidol, iohexol(omnipaque), ioversol, iopromideHigh osmolarIonic monomer- meglumine diatrzoate(hypaque, gastrograffin, urograffin)

ACCESSCommon femoral artery, popliteal, tibial, axillary, brachial, radial, carotid, subclavianBone/bony prominence beneath the arteryAvoid diseased areasAway from side brances, bifurcations, or crossing veinsExternal skin markings, ultrasound guided, fluoroscopy

Puncture site: common femoral artery on the medial 3rd of femoral head 1-2 cm below the inguinal ligamentA puncture site below the ligament cannot be compressed and could result in a large pelvic hemorrhagePuncture of the SFA must be avoided to prevent pseudo-aneurysm and hematoma correlate to the inefficacy of the compression

ACCESS1. Retrograde-relatively large diameter, ease of compression, options for image guided puncture2. Antegrade- commonly used for infrageniculate interventions, aortic bifurcations that are prohibitive to a contralateral retrograde CFA access and for chronic total occlusionsstraight line approach- easy maneuvering

ACCESS1. Single wall Puncture2. Double wall Puncture

Guidewires Composite construction Materials Stainless Steel Nitinol Jacketed CompositeHydrophilic/hydrophobic

Core Stainless Steel Used for support Stiffness varies based on taper / diameter of core Nitinol Used for its flexibility, memory and kink resistance Tip Platinum / Gold Provides radiopacity Atraumatic Ribbon formed for shaping tip

Grind & tip performance Stiff Intermediate Floppy

SheathsSheaths are hemostatic conduits inserted into the vessel. They allow passage of guidewires, catheters and interventional devices. Hemostatic valve at the tip and a side port for aspiration/administration of drugsHelps minimize local trauma to the vessel from repeated exchanges as well as decrease blood loss and hematoma formation

Sheaths Peripheral and coronary sheaths have a universal color code Universal color coding 4 Fr = red 5 Fr = gray 6 Fr = green 7 Fr = orange 8 Fr = blue 9 Fr = black 10 Fr = violet 11 Fr = yellow Sheaths are measured inner diameter in french size (1fr = .33mm)

catheters

Guide catheterDiagnostic catheterNon selectiveSelectiveCrossing

Endovascular surgeryTypically performed under LALess invasiveQuicker return to functionDurability compared to open surgical optionsHighly skilled operatorEndovascular suite with fluoroscopyCostly

Complications of endovascular proceduresSystemic, access site, or wire/catheter related complicationsContrast induced nephropathyIncrease age(>75 yrs), CRF(creatinine>1.5mg/dl), heart failure, DM, preprocedural hypotension, anaemia , ionic contrast mediumProper hydration, Minimum contrast doseAccess site-MCHematoma(3%), thrombosis(2%), bleeding, AVF, pseudoaneurysmHematoma-reversal of anticoagulation, vol resuscitation, hematoma evacuationCatheter related-dissection, distal embolization, perforation

Seldinger techniqueSven Ivar Seldinger- Swedish radiologist (1953)The Seldinger technique is a medical procedure to obtain safe access to blood vesselsThe desired vessel is punctured with a sharp hollow needle called a trocar, with ultrasound guidance . Guidewire is then advanced through the lumen of the trocar, and the trocar is withdrawn. A "sheath" or blunt cannula is passed over the guidewire into the cavity or vessel. After passing a sheath or tube, the guidewire is withdrawn.A sheath can be used to introduce catheters or other devices to perform endoluminal procedures. Fluoroscopy is used to confirm the position of the catheter and to manoeuvre it to the desired location. Injection of radiocontrast may be used to visualize organs.Upon completion of the desired procedure, the sheath is withdrawn. a sealing device may be used to close the hole made by the procedure.

Balloon angioplastyFogarthy (1963)- used endovascular catheter for extraction of arterial emboli and thrombiDotter and Judkins (1964)-transluminal treatment of arterial stenosisTypesPercutaneous transluminal angioplasty (PTA)Subintimal angioplastyPTA with stenting

TechniqueShortest distance from the access vessel to the target vesselRetrograde right common femoral artery accessTibial occlusive disease-I/L anterior common femoral accessHeparinization-5000 IU as standard bolus dose after arterial access. 1000 IU/L heparinized saline for flushingArteriography to identify the lesion and severityLesion crossed and contrast injectedBalloon diameter and length carefully chosen IVUS/CTA- for sizing the lesionBalloon inflated for 1 min, withrawn after deflating Contrast injection to assess the PTA result

Iliac and femoro popliteal segments. Less successful for below knee narrowingCoronary arteriesComplications- failure, hematoma formation, bleeding, thrombosis, distal embolisation

Subintimal angioplastyBolia et al (1989)-for chronic total occlusionsCreating an intentional subintimal plane across the occlusion with a guidewire and wire redirected back into the true lumenIliac and femoropopliteal occlusions- successful in highly calcified lesions, long occlusions(>15 cm)Higher patency rates were observed in limbs treated for claudication than limbs treated for chronic total occlusions and criticallimb ischaemia 12 month patency 55mm

Drug coated balloons(DCBs)Substantial amounts of antiproliferative agents were delivered to the arterial wall during short periods of balloon inflation.For prevention of re stenosis and myointimal hyperplasiaPaclitaxel coated balloons deliver drug during balloon inflation( superficial femoral artery)Drug eluting stents (DES) -coronary circulation/infrainguinal arterial occlusive disease-Sirolimus/paclitaxel-inhibits smooth muscle cell proliferation

StentingStent-comes from 19th century London dentist- Charles StentCharles Dotter (1983)-nitinol stents were first usedPalmaz et al (1985)-balloon expandable stent Two typesBare metal stentStent graftTwo types based on deployment methodBalloon expandableSelf expanding

Balloon expandableSelf expandableHigh radial/longitudinal forcePrecise placementFurther expansion with larger balloonsRadiopaque

Short lengthProne to crushingFlexibilityLong stent lengthsContinued radial force if oversizedCrush resistantAbility to clamp the stent

Low radial forceInaccurate/less precise placementLimited radiopacity

Angioscopy Used for visualizing the interior of blood vesselsArterial embolism, adjunctive procedure during vascular bypass to visualize valves within venous conduitVisualize stents in catheterization lab

Intravascular ultrasound Uses miniature ultrasound probe attached to distal end of an intravascular catheter(uses 20-40MHz)Useful with unreliable angiographic images-lumen of ostial lesions, or in regions with multiple overlapping arterial segmentsAdvantages over angiography-measures atheroma hidden within the vessel wall, identifies vulnerable plaque. Measures the effect of different treatment strategies for changing the evolution of the atherosclerosis disease process

Atherectomy Endovascular atherectomy allows the physical removal of atherosclerotic plaque material from the blood vessel, with a theoretical benefit of removing the obstructing plaque rather than mere displacing it, as with angioplasty and stentingOpen atherectomy remains the gold standard. Endovascular atherectomy is useful in vessels with difficult accessExcisional atherectomy catheters remove and collect the atheroma, whereas ablative device fragment the atheroma into small particles3 types of atherectomy devices

Directional RotationalLaser

Directional atherectomy Best suited for discrete calcified atherosclerotic lesions of infrainguinal arteries. Not used for chronic total occlusionSilverhawk plaque excision system-the device is advanced under fluoroscopic guidance to the proximal portion of the target lesion, where a carbide cutter excise the atheroma and traps it within the nose come of the device; once filled with plaque the device is removed, the nose cone is emptied, and the device is reintroduced over a guidewire

Rotational atherectomy utilizes a rotating burr or blade to excise plaque, whose microparticles are either aspirated or allowed to embolize distallyJetstream device success rate 99%.TLR -15% and 26% at 6 and 12 months respectively; restonosis 38% at 1yrMay cause vasospasm-calcium channel blockers/ nitroglycerine

Laser atherectomyUtilized in CTOs, both de novo or in in stent thrombosisCold tip laser that delivers burst of ultraviolet xenon energy in short pulse duration.Key features is the ability to debulk tissue without damaging surrounding tissue, minimizing restenosis

COMPLICATIONS-embolism 1.3%

Thromboembolectomy Management of acute thrombotic or embolic arterial occlusionsFogarty catheterPurely percutaneous thrombolectomyAspirationRheolytic devicesMechanical fragmentation with or without pharmacologic lysis

Simple aspiration either via a large sheath or guide catheter work well in small vessels< 6mmRheolytic devices utilize jets of saline, directed from the tip of the catheter back toward its more proximal portion, to create a venturi effect, resulting in clot lysis and aspiration.Arterial access is ideally made antegrade to the area of thrombotic occlusion. Lower extremity lesions are approached through contralateral femoral artery

Inferior vena cava filterPrevent life threatening pulmonary emboliRetrievable/ permanentIndicationsDVT/PE with contraindications to anticoagulationRecurrent VTE despite adequate anticoagulationPoor patient compliance(INR unstable), thrombolysisComplications-device migration, filter embolization, filter fracture, perforation of IVC, recurrent DVT, vena cava thrombosis

Intraarterial thrombolysisIn IA thrombolysis, the cervicocephalic arterial tree is traversed with an endovascular microcatheter delivery system, the catheter port is positioned immediately within and adjacent to the offending thrombus, and fibrinolytic agents are infused directly into the clot. This delivery technique permits high concentrations of lytic agent to be applied to the clot while minimizing systemic exposure.In acute ischaemic stroke within 6 hours of symptom onset It is usually infused over 1 to 2 hours while serial angiographic studies are obtainedreduced hemorrhagic complications (due to the use of lower doses of pharmacologic thrombolytics

Myocardial infarction, ischaemic stroke, massive PE, acute limb ischaemiaRecanalization rates for IAT have been shown to be superior to those for IVT for major cerebrovascular occlusions, averaging 70% versus 34%Agents usedStreptokinaseUrokinaseRecombinant tpaAlteplaseReteplase

Contraindications to thrombolysisIntolerable ischaemia(for arterial thrombosis)Active bleeding(not including menses)Recent stroke or neurosurgical procedure < 2 monthsIntracranial neoplasmsRecent major surgery( 0.5 cm/yrSaccular aneurysmsPoorly controlled HTN(DBP>100mmHg)Significant COPD(FEV1