Fuller: Chapter 32: Peripheral Vascular Surgery

Blockage in an artery, leading to ischemia and tissue death.

Infarction

Infarction

A blockage in an artery that may lead to ischemia and tissue death.

Vessel loop

A device used to retract a vessel during surgery. A length of thin Silastic tubing or cotton tape (umbilical tape) is passed around the vessel. The ends can be threaded through a bolster (a 1 8 -to 1 4 -inch [0.3-to 0.6-cm] length of rubber or Silastic tubing) to secure the loop against the blood vessel.

Intravascular ultrasound

A diagnostic tool in which a transducer is introduced into an artery and ultrasound is used to translate the physical characteristics of the lumen into a visible image.

Arteriosclerosis

A disease characterized by thickening, hardening, and loss of elasticity of the arterial wall.

f. AV shunt

A graft is implanted to form an anastomosis between the arterial and venous circulations. In this technique, the brachiocephalic vein and radial artery have been used. An alternative technique is direct anastomosis between the artery and vein.

Embolus

A moving substance in the vascular system. An embolus may consist of air, a blood clot, atherosclerotic plaque, or fat.

Hemodialysis

A process in which blood is shunted out of the body and passed through a complex set of filters for the treatment of end-stage renal disease (and in some cases, poisoning); also called renal replacement therapy.

In situ

A term meaning "in the natural position or normal place, without disturbing or invading surrounding tissues."

Hemodynamic

A term referring to the pressure, flow, and resistance in the cardiovascular system.

Percutaneous

A term that literally means "through the skin." In a percutaneous approach in surgery, an incision is not made; rather, a catheter or other device is introduced through a puncture site.

Define stent

A tubular device placed inside an artery for dilation, support, and prevention of stricture.

Stent

A tubular device placed inside an artery for dilation, support, and prevention of stricture.

Doppler duplex ultrasonography

A type of ultrasonography that amplifies sounds that pass through tissue and produces a visual image of blood flow.

d. Insertion of a vena cava filter

A vena cava filter is a metal, umbrella-shaped filter inserted into the inferior vena cava to prevent emboli from entering the pulmonary system. The filter can be temporary or permanent. The vena cava filter is inserted by percutaneous needle insertion. The procedure requires a guidewire and filter introducer. The guidewire is a fine flexible wire coated with a chemical (e.g., polytetrafluoroethylene [PTFE]), which prevents platelet aggregation and allows the wire to slide easily through the vessel. The filter itself, which resembles an umbrella without fabric, is made of titanium, stainless steel, or Nitinol. The patient is placed in the supine position on the fluoroscopy or radiology table. The groin is prepped with povidoneiodine solution and the area is draped in the usual manner. Local anesthesia with or without sedation is administered.

Clot of blood, air, or organic material that moves freely in the vascular system

Embolus

j. AAA

An abdominal aortic aneurysm is a condition in which a section of the abdominal aorta becomes thin and bulges because of atherosclerotic plaque and progressive weakening of the aortic wall. The surgical goal is to implant a graft extending from the aorta to both iliac arteries. This restores circulation to the lower extremities and pelvis. Each artery is opened, and the proximal ends are irrigated with heparinized saline. The bifurcated graft is trimmed and distal limbs anastomosed with 3-0 or 4-0 polypropylene suture.

k. Aortofemoral bypass

An aortofemoral bypass is performed to treat aortoiliac occlusive disease. A graft is implanted between the aorta and the femoral arteries to bypass the iliac arteries and restore circulation (Figure 32-24). Heparin is administered to the patient and the femoral arteries are clamped with right angle vascular clamps. The inferior mesenteric artery is clamped to prevent an embolus from entering it when the aortic clamp is applied.

g. AV fistula

An arteriovenous (AV) fistula is a direct anastomosis between an artery and a vein. The site is selected for patency and accessibility. After routine prep and draping of the area, an incision is made over the vessels. The vessels are mobilized with sharp dissection and anastomosed as for an arteriovenous shunt. The wound is closed in layers.

l. Axillofemoral bypass

An axillofemoral bypass creates circulation between the femoral arteries and the axillary artery. This restores circulation to the lower extremity or, in an emergency procedure, bypasses an infected aortic graft or aneurysm. The patient is given heparin intravenously and the axillary artery is clamped. The artery is incised with a #11 scalpel blade and the anastomosis is performed with 5-0 or 6-0 polypropylene suture. Suture lines are checked for leaks and the heparin is reversed with protamine. An angiogram may be obtained to ensure patency of the graft. Both wounds are irrigated and closed in layers.

e. What is the technique used in a femoropopliteal bypass?

An incision is made on the medial side of the thigh and carried to deep tissues with sharp and blunt dissection. 2 The femoral artery is mobilized and vessel loops are placed around it. 3 The distal incision is made on the medial side of the knee, inferior to the patella. 4 The popliteal artery is located and mobilized. 5 Angiograms are taken. 6 A synthetic graft is tunneled through the subcutaneous tissue, connecting the two wound sites. 7 The femoral artery is clamped and an arteriotomy is performed. 8 The proximal end of the graft is anastomosed to the femoral artery. 9 The popliteal anastomosis is performed. 10 Angiograms are taken and pulses are verified. 11 The wounds are closed after all bleeding has been controlled.

Arteriotomy

An incision made in an artery, usually to perform an anastomosis with a graft or another artery or to remove plaque or a thrombus.

Ballooning or dilation of an artery caused by stricture and increased arterial pressure.

Aneurysm

Thrombus

Any organic or nonorganic material blocking an artery; generally refers to a blood clot or atherosclerotic plaque but also includes fat or air.

Disease characterized by thickening, hardening, and loss of elasticity of the artery walls.

Arteriosclerosis

The most common form of arteriosclerosis, which causes plaque to form on the inner surface of an artery.

Atherosclerosis

Aneurysm

Ballooning of an artery as a result of weakening of the arterial wall. It may be caused by atherosclerosis, infection, or a hereditary defect in the vascular system.

Define blood pressure and list how normal blood pressure is affected:

Blood pressure is the force exerted on the arterial wall by the pumping action of the heart. The systolic pressure, the higher pressure, occurs during contraction of the ventricles (systole). The lower pressure, the diastolic pressure, occurs during the relaxation phase of the cardiac cycle (diastole). •Gender: Adult females generally have higher blood pressure than males. •Age: A gradual rise in blood pressure occurs from childhood to adulthood. •Weight: Blood pressure is higher in individuals with a high body mass index, regardless of age. •Exercise: Blood pressure rises with strenuous activity but returns to baseline level at rest. •Diurnal (daily) fluctuation: Blood pressure tends to rise during the day and is lowest in the mornings.

i. Carotid endarterectomy

Carotid endarterectomy is the surgical removal of atherosclerotic plaque from the carotid artery. Plaque is removed through an open incision in the artery. This reestablishes the flow of oxygenated blood to the brain. Carotid endarterectomy may be performed using either a general or regional anesthesia. When a regional anesthetic is used, the patient will respond to simple neurological tests, such as hand strength tests or speaking. The suture line is observed for leaks and blood flow confirmed with Doppler. Any leaks are repaired with additional sutures and controlled with topical hemostatic agents. Protamine sulfate is administered to reverse the effects of systemic heparin.

Angioplasty

Dilation of an artery using endovascular techniques (i.e., an arterial catheter); may include insertion of a supportive stent inside the artery to maintain blood flow.

f. After the case, what should you do?

During the immediate postoperative period, the patient's pedal pulses are monitored carefully. Possible complications include blockage of the graft and infection. Patients may experience some numbness of the lower leg. Swelling of the operative leg is common after surgery.

p. Saphenous vein graft

For a saphenous vein graft, the greater saphenous vein is removed to provide an autograft for peripheral or coronary artery bypass. The goal is to remove the vein yet retain its structural and physiological soundness. A general anesthetic usually is administered because the procedure is performed in conjunction with peripheral or cardiac bypass surgery. Frequent irrigation with saline solution is necessary. An Asepto syringe can be used for irrigation. Some surgeons inject papaverine or lidocaine into the subcutaneous tissue to prevent vein spasm.

Abnormal increase in blood pressure.

Hypertension

Abnormal lowering of blood pressure.

Hypotension

Drop in blood pressure related to reduced vascular volume.

Hypovolemia

o. Femoropopliteal bypass

In a femoropopliteal bypass, a synthetic graft or autograft is implanted between the femoral and popliteal arteries. As discussed previously, in situ grafting uses the greater saphenous vein as a shunt. During both anastomoses, the scrub should have heparinized saline solution available for irrigation of the arterial sites. Hemostatic agents are used to check bleeding at the anastomosis and additional sutures are placed if needed.

n. In situ saphenous femoropopliteal bypass

In situ saphenous vein bypass is a surgical alternative to the use of a synthetic graft to bypass a diseased femoral artery. The saphenous vein is not removed but is left in anatomical position. In the technique described here, a continuous incision is made along the entire saphenous vein. This is the safest method and allows complete ligation of tributaries. The distal or narrow end of the vein is anastomosed to the popliteal artery and the proximal vein is anastomosed to the large end of the femoral artery. The goal is to produce vascular continuity with an autograft.

Lack of blood and therefore oxygen in tissue.

Ischemia

Umbilical tape

Lengths of cotton mesh tape used to loop around a blood vessel for retraction. See vessel loop.

Case Study 1: You are relieving the surgical technologist on a bilateral femoropopliteal bypass. a. What is the first thing you should do when you scrub in?

Make sure count is correct and be updated on procedure.

a. Endarterectomy

Many vascular procedures require removal of atherosclerotic plaque from the inside of the artery (endarterectomy). Plaque is a rubbery substance that adheres to the tunica intima, causing stenosis or occlusion.

q. Management of varicose veins

Surgical treatment of varicose veins involves the removal of dilated and tortuous (varicose) veins and their tributaries to prevent symptoms and to improve cosmetic appearance. A general or regional anesthetic is administered.

e. Vascular access for renal hemodialysis

Patients with severe or end-stage renal disease require frequent hemodialysis. This treatment requires long-term access to the patient's vascular system. An anastomosis between the arterial and venous systems is created surgically to produce this access. Two techniques usually are used to create vascular access: an arteriovenous shunt or an arteriovenous fistula. A local anesthetic usually is used.

Venous stasis

Pooling of blood in the veins caused by inactivity or disease. Stasis can cause distention of the veins.

b. Intraoperative angiography

Preoperative angiography (arteriography) is the injection of contrast medium into a selected artery and its branches to determine the exact location of strictures, occlusion, or malformation. During surgery, intraoperative angiography is used in conjunction with angioplasty to allow the surgeon to see the position of the stricture and to place the catheter in the correct location. A solution of 60% Renografin is frequently used. A third syringe of IV saline is prepared to flush the contrast medium from the arteries when radiography has been completed.

Bifurcation

The Y-shape of an artery or graft.

Ischemia

The decrease in or absence of blood supply to a localized area, usually related to vascular obstruction.

h. Thrombectomy

The goal of thrombectomy is to remove a stationary clot in a blood vessel. This restores circulation and prevents emboli. Thrombectomy is commonly performed with an embolectomy catheter. The scrub should have heparinized saline, vessel irrigation tips, vascular sutures, ties, and hemostatic agents available. A variety of vascular clamps matched to the size of the vessel (or the surgeon's preference) also should be available on the instrument table. Small-bore suction and larger atraumatic suction tips are needed. Vascular forceps are used throughout

c. What types of sponges should you have on the field?

The groin incision is closed in layers and dressed with gauze squares.

Lumen

The inside of a hollow structure, such as a blood vessel.

Atherosclerosis

The most common form of arteriosclerosis, which causes plaque to form on the inner surface of an artery.

What is the proper method of handling an amputated limb during surgery?

The scrub removes the limb from the field and may pass it directly to the circulator.

d. What extra sterile equipment should you have on the field?

The surgeon chooses the appropriately sized graft. The greater saphenous vein may be used instead of a synthetic graft (see the following section). A tunnel is made in the subcutaneous tissue and the graft is carried from the upper to the lower wound. The graft is then drawn back into the popliteal space.

Endarterectomy

The surgical removal of plaque from inside an artery.

c. Transluminal angioplasty

Transluminal angioplasty is the insertion of an arterial catheter or stent into an artery to establish patency and normal blood flow. A common type of balloon-expandable stent is the Palmaz stent.

Voluntary action in which air is forced against a closed glottis.

Valsalva

List the diagnostic procedures associated with peripheral vascular surgery.

a. ARTERIAL PLETHYSMOGRAPHY A pulse volume recorder is used to measure the arterial pulse waveform during systole. For this test, three blood pressure cuffs are placed on the leg and inflated to 65 mm Hg. Each cuff reading produces a waveform, which is compared with the waveforms from the other two cuffs. A reduced wave in one area may indicate reduced blood flow at that point. b. Doppler scanning intensifies the sounds made by blood flowing through a vessel. The pitch, rhythm, and quality of the sound reflect pressure, volume, and flow rate. c. Arteriography is radiographic imaging of the artery. This is done as an intraoperative, diagnostic, or interventional procedure to delineate the shape and interior surface of the arteries. d. Intravascular ultrasound is used in both peripheral and coronary surgery to map the lumen of a vessel. A rotating flexible catheter carrying a transducer is introduced into the vessel.

List the blood vessels of the body, define and give an example.

a. Major arteries- The largest artery of the body is the aorta. It emerges from the heart in an arch at the left ventricle and curves downward to descend through the thoracic cavity, passing behind the heart but in front of the spinal column. b. Thoracic cavity- The aorta arises from the left ventricle of the heart to form an arch (the aortic arch). Three major arteries arise from the top of the arch: the brachiocephalic artery, the left common carotid artery, and the left subclavian artery. c. Head- The brachiocephalic artery gives rise to the right common carotid artery, which branches to the external carotid artery and the arteries of the brain. The vertebral artery, which branches from the brachiocephalic artery, follows the cervical vertebrae and branches distally to the arteries of the head. d. Upper extremities- The brachiocephalic artery branches into the right common carotid and the right subclavian arteries. These supply blood to the right side of the head, neck, right shoulder, and upper arm. The left common carotid artery supplies blood to the left side of the neck and head. The left subclavian artery provides blood to the left shoulder and right arm. e. Abdomen- The descending aorta continues through the abdomen and branches to the celiac trunk, a network that gives rise to the gastric, splenic, and hepatic arteries. f. Lower limbs- The iliac arteries divide into the internal and external iliac arteries in the pelvis and the external iliac artery converges into the femoral artery in the groin. g. Major veins- The largest vein of the body is the vena cava, which is divided into inferior and superior segments. The venae cavae communicate with the heart through the right atrium. The superior vena cava receives deoxygenated blood from the head, neck, and upper extremities, and the inferior vena cava receives blood from the lower body and extremities. h. Portal circulation- The hepatic portal circulation is unique in structure and function. The superior mesenteric and splenic veins converge to form the portal vein. This large vessel carries nutrients from the digestive system into the liver and also supplies about 60% of that organ's oxygen requirements. The hepatic veins carry blood out of the liver to the vena cava.

List and give an example of instruments used in peripheral vascular surgery.

a. Vascular clamps are specifically designed to prevent trauma to blood vessels. The jaws contain finely serrated inserts that grip the tissue but do not crush or damage the surface of the vessel, even when fully closed. (Debakey clamps) b. Vascular scissors are extremely sharp and fine. Many are angled so that the tips can be easily inserted into the vessel. (Potts, De Martel) c. Vascular forceps (pickups) have very fine serrations at the tips to allow a secure grip without tearing or slipping. The most common vascular forceps are DeBakey forceps. d. There are few vascular-specific retractors except small vein retractors, which are also used in general surgery. Nonpenetrating shallow retractors are commonly used during superficial vascular surgery. A dull Weitlaner (self-retracting) or spring retractor should be available for skin and subcutaneous retraction in the hand, arm, or superficial leg. Handheld retractors include the Senn retractor, vein retractor, and shallow Richardson retractor. Skin hooks occasionally may be needed. e. Small suction tips, such as the Frazier tip, are commonly used in most vascular procedures. The suction pressure should be lowered for use on the actual vessels. General surgical tips, such as the Poole (vented) or Yankauer suction tip, are used in abdominal vascular surgery. f. A tunneler is used to burrow a channel through connective tissue to make space for a tubular vascular graft.

List the equipment, medication, and supplies used n peripheral vascular surgery and give an example.

a. Vascular sutures range in size from 3-0 to 11-0. Cutting and taper needles used for anastomosis are 3 8 curved needles. Synthetic monofilament or coated material is preferred over plain braided suture, because it is nonreactive and prevents endovascular clotting and emboli. Vascular suture materials include polyester (Mersilene), polypropylene (Prolene), polyhexafluoropropylene (Pronova), Gore-Tex, and silk. Suture-needle combinations are very delicate and require careful handling. Only fine-tip needle holders should be used. Cardiovascular (CV) sutures are available as single needles or double-arm needles. b. Vascular grafts are used to replace a blood vessel or to patch a vessel. Synthetic grafts are made of Dacron, polyester, or Gore-Tex. Sources of biological materials are banked human umbilical cord and autograft (usually from the saphenous vein). Grafts may be straight or bifurcated (Y-shaped). The length is measured in centimeters and the diameter reflects the outside diameter. c. The most common method of removing thrombi is with a Fogarty-type embolectomy catheter. This is a narrow flexible catheter with a firm tip surrounded by an inflatable balloon. d. The central venous catheter, known commonly as a central line, was introduced in Chapter 13 as a method of administering IV drugs, solutions, parenteral nutrients, and for blood draws in patients that require long or medium term therapy. Central line catheters are constructed of polyvinyl choride, Teflon, polyurethan, or silastic (silicone elastomer blend). e. An endovascular stent is a tubular mesh implant that fits against the wall of an artery. The stent thus provides a physical barrier between the atherosclerotic plaque and the vessel lumen. It also holds the vessel open so that blood can flow freely without platelet aggregation. Stents are made of stainless steel, titanium, or a metal alloy called Nitinol. f. During vascular surgery, blood vessels are mobilized and positioned for incision and entry. Retraction is performed with a vessel loop. Several types of loops are available. The most common is a thin length of Silastic material, which is carried around the vessel with a right-angle clamp. The ends of the vessel loop are clamped together with a hemostat. Umbilical tapes (18 inches [45 cm] by 1 8 -or 1 4 -inch [0.3-or 0.6-cm] flat, mesh cotton) are available prepackaged for use as vessel loops. A vessel loop may also be used to occlude a blood vessel by acting as a tourniquet. g. Anticoagulation-During vascular surgery, heparinized saline solution is used to prevent coagulation in the area of the operative vessels. This prevents thrombi from forming at the surgical site and reduces the risk of embolus. Systemic heparin may be administered just before arterectomy (incision into the operative artery) begins. Heparinized saline is prepared by the scrubbed surgical technologist. Coagulation- Hemostasis is maintained at anastomosis sites with collagen or fibrin products, such as microfibrillar collagen hemostat (Gelfoam, Avitene) or topical thrombin.

m. Femorofemoral bypass

femorofemoral bypass involves implantation of a prosthetic graft that connects the femoral artery on the affected side to the opposite femoral artery. This is done to bypass unilateral atherosclerotic disease in the iliac artery. Hemostatic agents are applied to the suture lines. Protamine sulfate may be administered to reverse the effects of systemic heparin.

b. What types of medication should you have on the field?

scrub should have heparinized saline solution available for irrigation of the arterial sites. Hemostatic agents are used to check bleeding at the anastomosis and additional sutures are placed if needed.

List the structures of the blood vessel and define.

•The tunica externa (also called the adventitia), which is composed of connective tissue and protects the vessel from injury and provides structural strength. •The tunica media, which is composed of inner layers of smooth muscle bounded by connective tissue. Smooth muscle is under the control of the autonomic nervous system. •The tunica intima, which secretes substances that cause vasodilation or constriction, as well as substances that prevent platelet aggregation in the vessel. The structure of arteries and veins is shown in Figure 32-1.