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Adv. Vas. Son.
Test 2 Arterial Bypass Grafts and Stents
| Question | Answer |
|---|---|
| What is saphenous vein mapping used for? | CABGs, To revascularize the leg w/ a femoro-popliteal ot femoro-tibial bypass graft |
| What can the cephalic vein be used for? | Removed and used for short segment grafts |
| Cephalic and basilic are carefully evaluated for what? | Pre-op for hemodialysis access placement |
| The Radial/Ulnar artery can be used for what? | CABG material |
| A pre-op assessment decreases what and increases what? | DECREASES limb morbidity and INCREASES CABG patency rates |
| How many procedures does Saphenous vein mapping for bypass grafts consist of? | 3 |
| What is the 1st procedure for saphenous vein mapping for bypass grafts? | Determines vein suitability |
| What are the goals of procedure 1: Determining vein suitability? | Is the SV patent & present? Continuous? Consists of a double or duplicates system? Does it have residual thrombus? Is it of appropriate size? |
| What is the 2nd procedure for saphenous vein mapping? | Procedure 2 includes procedure 1, BUT also involves mapping and marking the course of the saphenous or superficial arm vein(s) |
| What is the 3rd procedure for saphenous vein mapping? | Procedure 3 determines the suitability of the radial artery for CABG is appropriate |
| If the GSV is functioning as a collateral vessel or major outflow vessel, then its removal (harvest) is what? | Contraindicated |
| What probe is used for vein mapping? | 7.5-15 MHz TD |
| Do you measure the GSV in TRV or LONG and where do you measure? | TRV, and upper thigh. mif thigh, lower thigh, Upper calf, Mid calf, and Lower calf |
| If the ipsilateral GSV is too small (?) or unsuitable evaluate the contralateral GSV | <2.0 mm is too small |
| SSV measurements should be performed with the leg in what position for the maximum vein dilatation? | Dependent |
| Vein diameter will expand by _________ times when arterialized? | 1.5-2 |
| Vein diameters of _________ have a higher graft patency rtes | ≥2.5 mm |
| Veins <____ have a high graft failure rates in lower extremity bypass | <2.5 mm |
| If surgery is planned do what to the leg? | Mark the leg with pen to map map it |
| If only suitability is the goal there is no need to do hat to the leg during the exam? | no need to mark it |
| What is an "In Situ" bypass also known as? | Orthograde |
| What happens with an "In Situ"/ "Orthograde" bypass? | The GSV remains in place |
| What are the valves excised with? | A valvulatome |
| What happens to perforating veins and tributaries? | Ligated and cut |
| The proximal GSV is _______ and ________ into the ____? | Prox GSV CUT and SEWN into CFA |
| The vein is sewn Prox/Distal to bypass the occluded arterial segment? | DISTALLY |
| What are the advantaged for using the Radial A instead of the Saph V for CABG? | Appropriate vessel caliber, Thicker walls, Less hyperplasia, Better availability (not all candidates have appropriate GSV) |
| What are the contraindications of using the Radial A? | Ischemic digits, Raynaud's, Ipsilateral athero-occlusive disease in arm, Sclerotic/arteric or occluded Radial A, & Incomplete palmar arch in hand |
| What is the average inside diameter of the distal radial artery in men? Women? | MEN= 2.8mm, WOMEN= 2.4mm |
| What is the preferred diameter of the distal radial artery for surgeons? | at LEAST 2.0mm, BUT 2.5 mm or greater is PREFERRED |
| Palmar arch patency is ____? | ESSENTIAL |
| What does the Palmar arch provide? | Provides a collateral pathway so that the entire hand and all digits can be perfused by the ulnar artery when the radial artery is harvest |
| How do you evaluate the palmar arch? | Allen's test or PPG tracing |
| What is a PTFE? | Synthetic Bypass graft, Polytetrafluoroethylene- A form of teflon, |
| Where are synthetic grafts favored? Where not favored? | Favored in the abdomen, and thigh. Not favored below the knee |
| What does "Autogenous" mean? | Means the PTs own veins |
| What is an Aorto-bifemoral Inflow graft? | From AO to distal iliac or CFS, Bilat. Used to bypass distal AO or more commonly iliac A disease. |
| With an Aorto-bifemoral inflow graft where will PTs have a scar? | Near the umbilicus and one in each groin regoin |
| What is a femoral to femoral "jump" graft? | Used to bypass one iliac artery stenosis or occlusion, one iliac artery will supply flow to both legs |
| What is the intended flow with a fem-fem jump graft? | Intended flow direction should be from ASX leg gto pre-op SX leg |
| What is an Axillo-femoral graft? | From the Axillary A to the distal EIA or CFA, used with the Fem-Fem jump graft, Bypasses severe aortoiliac disease (bypasses abdominal AO) Less frequently used |
| Facts about the Synthetic Polytertrafluoroethylene (PTFE) graft | CFA to distal SFA or Prox POP A, Graft kinking is a complication of the type of graft if it goes below the knee |
| Newer flexible fabrication may allow what with the PTFE? | Placement to extend below the knee |
| Facts about the Synthetic Dacron | Often used for fem-fem & iliac grafts, Advances in Dacron material is now allowing feoral-distal bypass grafts, "Vacuum cleaner hose"-- Looks all wavy on ultrasound |
| In Situ vein graft facts | Used to bypass femoro-poplital occlusion, Often extended from CFA to distal Tibial A (AKA fem-distal graft) |
| Vein grafts appear to have better what than syntheti rafts in legs? | Patency rates |
| With an in-situ vein graft the graft lies superficially in _____ segments, but is deeper at the _______ anastomosis | PROXIMAL segments, DISTAL anastomsis |
| The PROX anastomosis is usually ___? | Usually at the CFA, but may originate at the Profunda femoris artery (PFA) or the Prox SFA |
| Vein grafts may extend to distal________? | PTA (or less frequently ATA) |
| What can occur if a non-ligated perforator is large? | A "steal" can occur, Flow down the graft into the perforator & back into the deep vein, May cause ischemia in the distal limb |
| Describe the Reversed-Vein bypass: | Perforating Vs & tributaries are ligated. GSV removed. Vein is reversed & implanted as bypass (retrograde). Can be used in ontralateral leg. |
| What graft is smaller Proximally, and larger distally due to the diameter of the reversed vein? | Reversed-vein Bypass |
| Why do some surgeons prefer this reversed vein bypass method over others? | Some surgeons prefer this method, as distal anastomotic stenosis (by neointimal hyperplasia) has less of an effect due to the wide bore of the vein |
| The SSV is used for what? | Small segments or for graft revisions |
| The Cephalic or Basilic veins in the arm may be used for what? | Small graft extensions or revisions |
| What is the stenosis rate within one year of a bypass graft? | 20-30% |
| Stenosis in post-op 1-30 days is due to what? | Technical error or valve issues |
| Beyond 30 days why might grafts fail? | Intimal hyperplasia (myoinitimal hyperplasia), Graft kinks, Stenosis @ Prox or Distal anastomosis |
| During first 30 days, technical problems are more likely to occur: | Retained valve or valve leaflet, Intimal flap, Probs @ anastomotic site due to suture placement, Graft entrapment due to improper positioning, Thrombosis due to inadequate conduit or limited runoff |
| If a graft thromboses: high __________ if graft undergoes thrombectomy | Failure rate |
| If a graft occludes there is a what % chance of re-thrombosis folloeing thrombectomy? | 50-80% |
| 60% of graft stenosis are what? | Asymptomatic due to limited ambulation |
| What can be a bypass failure after 24 months? | Progression of atherosclerotic disease in inflow or outflow vessels, Aneurysmal dilation |
| What is the routine protocol for a sonographic exam following a graft? | First ultrasound performed w/in 3 months post-op, First year-looked @ every 3 months, Second year- looked @ every 6 months, Annually thereafter |
| DO NOT PUT CUFF OVER what? | A graft |
| A drop of ____ in the ABI from the previous exam suggests what? | 0.15 in the ABI suggests progressive graft stenosis |
| Where do you evaluate for a graft? | Inflow & anastomosis. Evaluate for: stenosis, wall irregularity, Aneurysm/psuedoaneursym, A-V in nonligated perforators, Partially excised valve leaflets causing stenosis |
| True stenosis has what? | An abrupt increase in velocity |
| When should you obtain & record Peak systolic velocities from the following locations: | Prox, @, & distal to any stenotic segment, The inflow artery segment Prox to graft, W/in the graft (Prox, Mid, Distal), The outflow artery segement distal to graft |
| How is the Mean Graft Flow Velocity (GFV) calculated? | By taking the avergae of 3-4 PSV values in non-stenotic graft segments at verious levels |
| What is NORMAL GFV? | >45 cm/s |
| What does a GFV in a normal sized graft of <40 cm/s indicates? | Probable failure |
| What does a GFV decrease of greater than 30 cm/s from previous study indicate? | Failure |
| Normal grafts should have what type of waveforms? | Triphasic, like the native valve |
| With PTFE grafts what kind of artifact can be seen? | An aura of "Christmas Tree" lights |
| With PTFE ultrasound may not penetrate what? | Air |
| Velocities in normal reversed vein grafts will _____ distally as the diameter becomes larger? | DECREASE |
| What is the PSV & Vel ratio of a >50% graft stenosis? | PSV ≥ 150 cm/s & VEl ratio of ≥ 2.0 |
| Abnormal over Normal = what? | Velocity ratio |
| If it's ≥ 70% stenosis what is the Vel ratio? PSV? ans GFV? | Vel Ratio ≥3.5, PSV >300 cm/sec, GFV <40 cm/s in a normal sized graft |
| Grafts in the ≥ 70% stenosis category have what? | High failure rate & should be revised/repaired |
| How many Peripheral Stents are there and what are their names? | 2 Basis Types- Palmaz, Wallstent |
| What is the Palmaz peripheral stent? | Balloon deployed-used with anigoplasty |
| What is the Wallstent peripheral stent? | Self expanding- contained in a sheath like catheter that is drawn back allowing the stent to expand |
| What are stents made out of? | Titianium, nitinol or similar material can can be opened or covered |
| Where are the stent sites for the peripheral vascular? | Ao, Renals, Iliacs, and Femoral-popliteal |
| What is an Iliac stent assessment challenging? | Challenging due to depth, obesity, and bowel gas |
| If a Femoro-popliteal stents is overlapping what could happen? | They could come apart and cause a pseudoaneurysm |
| What are Femoro-popliteal stent omplications? | Restenosis (initmal hyperplasia), Thrombosis, Stent shift, Stent fracture, Aneurysm at stent edge!!! |
| In a 50-79% stenosis what is the PSV, andVR | PSV > 190 cm/s, and VR 1.5 |
| In a ≥ 80% what is the PSV and VR? | PSV >375 cm/s and VR 3.5 |
Created by:
EmilyGriffin
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