Saphenous Vein HarvestingTips, Tricks and Pitfalls

bySA Mohamad Fadzly

Introduction

• Surgery for revascularization of the myocardium continues to be an effective and lasting means of managing patients with multivessel coronary artery disease• Increasing popularity of PTCA and related interventional procedures:

o Atherectomyo Intravascular Stents

• Not been a significant decrease in number of patients undergoing CABG• CABG surgery continues to be one of the most commonly performed

surgical procedure

Conduit of Choice

The greater saphenous vein has been extensively used as a conduit after internal mammary artery because :

• It can be procured conveniently• Easy to handle• An excellent inflow Khonsari, Sintek (2007)

Internal Mammary Artery vs Saphenous Vein Graft

• Although the saphenous vein can remain patent for years, the artherosclerosis is widely documented that using the internal mammary artery as a conduit has gained much prominence.• IMA – conduit of choice•Why? Appears to resist the development of atherosclerosis

Has a higher late-patency rate than a comparable saphenous vein graft

• Long-term follow up has definitely revealed significant improvement in 10 years survival rates and a marked reduction in the incidence of late cardiac events in patients who have undergone left IMA bypass graft to the LAD coronary artery

• Internal thoracic arteries demonstrate better patency than saphenous veins except when grafting moderately stenosed right coronary arteries. When bypassing right coronary arteries with less than 70% stenosis, saphenous veins may be a better choice.

Sabik, et all (2005)

Intra Operative Vessel Harvesting• Anatomy of the greater saphenous vein • Selection of vessel• Positioning• Prepping• Draping•Open (continuous) / Bridging Harvest Technique• Preparation of the Vein•Wound Closure

Greater Saphenous Vein - Anatomy• The GSV originates from where the dorsal

vein of the first digit (the large toe) merges with the dorsal venous arch of the foot.

• After passing anterior to the medial malleolus (where it often can be visualized and palpated), it runs up the medial side of the leg.

• At the knee, it runs over the posterior border of the medial epicondyle of the femur bone.

• The great saphenous vein then courses laterally to lie on the anterior surface of the thigh before entering an opening in the fascia lata called the saphenous opening.

• It joins with the other femoral vein in the region of the femoral triangle at the saphenofemoral junction.

The selection of SV is determined by :• Age of patient• Diabetes• Peripheral vascular disease• Varicosities• Previous vein stripping• Previous CABG

Preoperative AssessmentAssessment of risk factors :Treadwell (2003)

• Diabetes mellitus• Smoking• Obesity• Peripheral vascular disease• Use of intra-aortic balloon pump

Diagnostic Tests

• Echocardiography ( evaluates heart structure and function )• Ejection fraction / ventricular wall motion• Cardiac catheterization report• Labs report : (in particular but not limited to : WBC, HGB,

HCT)

Physical AssessmentHistory of :

• PVD• Varicose veins• Previous vein harvesting• Previous vein stripping• Deep vein thrombosis

Diagnostic Studies

Performed to determine the adequacy of saphenous vein

• Doppler studies• Venography• Venous mapping ( done to locate the

saphenous vein )

Be Wise in Making Judgement

Harvesting veins from lower limbs with evidence of infection or ulceration should be avoided if possible

Skin Infection or Ulceration

Varicosities

• Saphenous vein with varicosities should be avoided

• The walls of the vessels are abnormal dilated and the caliber predisposes to lower flow velocity and possibly early thrombosis and occlusion will occur

Peripheral Vascular Disease

• A wound in the lower leg intends to heal slowly, this is of particular significance in the elderly diabetic patient with peripheral vascular disease

• Handling of tissues and careful wound closure are mandatory

• It is perhaps preferable not to harvest veins from the lower legs of elderly patients with diabetes or PVD

Prepping• A shower with antibacterial soap the night before and the

morning day of surgery• Hair is clipped from the patient’s anterior chest, bilateral

groins and bilateral medial legs a night before surgery• After induction and positioning, skin scrubbing will be done

with beta solution, Povidone Iodine, it is include the anterior chest from chin to groin, bilateral groins and bilateral legs, circumferentially

Selection Length of the VesselLength of the vessel needed :• Echocardiography to evaluates heart structures and LV function• CXR – to measure any heart enlargement• Coronary angiogram – to determines exact location of the coronary

blockaged•Determined by the Surgeon•Anterior coronary bypasses generally requires about 10 – 15 cm of

conduit•Posterior bypasses proximately about 20 cm•Lateral bypasses proximately about 15 cm

Positioning

• The supine position provides optimum exposure for CABG

• Sterile soft linen should be place under the thigh to provide good access during procurement

• Legs should be slightly flexed and externally rotated after prepping and draping to provide good exposure of the saphenous vein and femoral arteries for insertion of intra-aortic balloon pump if necessary

Draping• The feet are wrapped with sterile towels or a stockinette• The legs are flexed into a “frog-like” position• A roll of sterile towels or sheets may be used to keep the legs

in the slightly flexed position• The perineum is covered and a towel may be placed across

the umbilicus connected to the side drapes• Cardiovascular drape is then placed over the patient

Saphenous Vein Landmarks First constant anatomical landmark :Arises anterior edge of the medial malleolus. It has a linear course in the leg. It ascends vertically , posterior to the medial border of the tibia and is accompanied by the leg branch of the saphenous vein

Second constant anatomical landmark :At the knee, the long saphenous vein travels posteriorly to the lateral femoral condyle. It then travels superficially over the medial region of the thigh , remaining parallel to the medial edge of the sartorius muscleTwo nerves structured accompany the long saphenous vein :1. The accessories nerve of the medial saphenous nerve2. Anterior branch of the medial musculocutaneous nerve

Saphenous Vein Landmarks

Femoral Triangle :The long saphenous vein forms an arch as it penetrates into the depth of the thigh. It perforates the cribriform fascia immediately above Allan Burn’s ligament. This corresponds to a reinforcement or fold of the cribriform fascia

Third constant anatomical landmark :An arch of the long saphenous vein opens onto the anterior surface of the femoral vein 4 centimeters below the inguinal ligament

Saphenous Vein Harvest MethodsMethods :

• Open - Complete continuous open technique - Interrupted bridging skin incision technique

• Endoscopic

Open method• If the vein from the lower leg is to be used, the initial skin

incision is made anterior to the medial malleolus

• If the upper portion of the vein will be used, the initial skin incision is made in the groin. An incision is made one-to-two fingerbreadths from the femoral artery pulse and the subcutaneous tissue is dissected to expose the greater saphenous vein

• The desired plane is accessed by blunt dissection with scissors down to the level of the vein

• Skin and subcutaneous fat are undermined with scissors (or tunneling with fingers if bridging), staying just superficial to the vein and spreading the tips of the scissors over the vein

Skin Incision Along the Knee

• The incision alongside the knee joint is subjected to cause strain and stretch in several directions as the joint moves.

• This may give the patient significant discomfort and interferes with satisfactory healing.

• Therefore, the skin in this location is usually left intact

During the Procurement

• Creation of skin flaps should be avoided• Care should be taken to preserve the saphenous

nerve• The “no-touch” technique should be utilized. This

means handling the vein only by its adventitia with atraumatic forceps, isolating the vein with vascular band / tapes

• Remove the vein from its ‘bed’ by careful dissection and division of its branches

• Tissue should be dissected around the vein• All branches should be ligated. If bridging

technique is used, ligate the branches once the vein is explanted

Try to Avoid

Try to Avoid Accidental Division of the Vein

With the aid of scissors the skin incision is extended over the index finger, which has tunneled above and parallel to the saphenous vein. This technique prevents accidental division of a more superficially placed of the vein and eliminates the development of unnecessary dead spaces or redundant skin flaps

Intimal Injury

• The vein must never be pulled or stretched to facilitate dissection

• The intimal layer is very delicate and may tear• It will rise a formation of platelet aggregation

and possible subsequent early occlusion of the graft

• This is more likely occur when multiple skin incisions are made and the vein has to be harvested from beneath the skin bridges

Pulling or stretching vein injures the intima

Gentle retraction with elastic band

Nerve Injury

• The saphenous nerve runs along the greater saphenous vein.

• Special care should be taken not to accidently or divide it to avoid postoperative paresthesia

PREPARING THE VEIN

• When adequate segment of vein is dissected free, it is divided at each end and removed

• The vein stumps in the groin and the ankle are securely ligated with 3/0 Ethibond tie

Localized Varicosities

• Localized varicosities can be detected along the vein wall when it is being gently distended• They can be partially excluded by

the application of metal clips on the redundant tissue parallel to the vein wall Excluding a localized varicosities

Over Distension the Vein

• The vein graft should be gently distended• Any excessive pressure can result

intimal tear and disruption• Try to prevent the intraluminal

pressure from exceeding 150 mmHg• Gently applying a squeezing

technique from proximal to distal end

Gently distending a vein

Branch Stumps

• The branches should be ligated or clamped approximately 1 mm from the vein wall to minimize the presence of a stump, which may predispose to thrombus formation and early graft occlusion

• Any stump can easily be eliminated by application of a fine metal clip behind the tie parallel with the vein wall

Leaving excess stump on a vein branch

A metal clips eliminate vein stump

Graft Narrowing

• Conversely, the tie or metal clip should never occlude part of the vein itself

• This gives rise to localized constriction• The tie or clip should be gently removed• Applying pressure with a heavy needle holder

on the closed loop of the metal clip by separate the two ends and facilitate its removal

• The tie or metal clip is placed or reapplied appropriately

A clip constricting vein

Adventitial Constriction• The adventitial tissue may at times

be caught in the tie around one of the branches, creating a localized constriction

• The adventitial should be carefully divided with Pott’s scissors

Dividing the adventitial band to relieve constriction

Suturing the Vein Wall

• Sometimes, the wall of the vein at the site of the avulsion of its branches requires suture closure

• This can be accomplished by taking longitudinal bites of the vein wall with 7-0 or 8-0 Prolene when it is being distended

• But the transverse suturing gives rise to localized constriction

Transverse closure of an avulsed branch leads to constriction of a vein

WOUND CLOSURE

• The leg wound is closed in layers with absorbable sutures

• In the groin region or where the wound is deep, an extra layer of closure is necessary

• The skin is close with fine absorbable suture material with 3/0 cutting needle in a subcuticular manner

Interrupted Mattress Sutures

• Patients with diabetes and peripheral vascular disease are prone to poor wound healing and at risk of wound infection

• The wound must be closed atraumatically without leaving any dead space

• Absolute hemostasis must be achieved before closure begun

• Interrupted horizontal mattress monofilament sutures that are left in place until satisfactory healing has been completed, usually for at least 2 to 3 weeks post-op

Wound Drainage

• If the wound is deep or continues to ooze blood, closed-system drainage for 24 hours should be used

• This prevents hematoma formation and possible deep wound infection

Interrupted Skin Incision

• In patients who are diabetic or peripheral vascular disease are prone to poor wound healing• Multiple skin incision are made,

leaving intervening bridges of skin intact• This allow better closure of the

wound and minimizes ischemic changes along the skin edges

Postoperative Assessment (Evaluation of Postoperative Patient Outcomes)

• Assess lower extremities for nerve damage due to being placed in the “frog-leg” position

• Post-operative bleeding – monitor dressing and wound for excessive drainage and swelling

•Monitor for skin infection and ulceration

REFERENCES• Khonsari, S., Sintek, C.F. (2007). Cardiac surgery safeguards and pitfalls in operative technique (4th ed.) Los Angeles, USA: Walters Kluwer Health/Lippincott Williams and Wilkins.

Sabik, J.F., Lytle, B.W., Blackstone, E.H., Houghtaling, P.L., Cosgrove, D.M. (2005). Comparison of Saphenous Vein and

Internal Thoracic Artery Graft Patency by Coronary System.The Society of Thoracic Surgeons, 79:544 –51.

Treadwell, T. (2003). Diagnostic dilemma : Management of Saphenous Vein Harvest wound complications following Coronary Artery

Bypass grafting. Diagnostic Dilemma, 15(3), 83 – 91.

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