The Modified Bentall Procedure for Aortic Root Replacement

Written By: Sam Savage

Published Date: July 21, 2006 Last Edited: July 21, 2006

By Cherry, Cecile; DeBord, Starla; Hickey, Carol

ABSTRACT

* THE BENTALL PROCEDURE is a surgical repair of an ascending aortic or aortic root aneurysm in combination with aortic valve disease. Less commonly, it is used to repair aortic dissection affecting the aortic root and valve.

* DURING THE PROCEDURE, a composite aortic valve graft is used to replace the proximal ascending aorta and aortic valve. The procedure is performed through a median sternotomy during cardiopulmonary bypass.

* IN THIS MODIFICATION of the original procedure, coronary artery circulation is maintained by removing a full-thickness “button” of aorta surrounding the coronary ostia, making it easier to implant the proximal end of the coronary arteries into openings made in the aortic vascular graft. AORN J 84 (July 2006) 52-70.

AORN, Inc, 2006.

The Bentall procedure is a surgical repair of an ascending aortic aneurysm or an aortic root aneurysm that is accompanied by aortic valve incompetence. Less commonly, this procedure is used to repair aortic dissection affecting the aortic root and valve. The procedure uses a composite aortic graft (ie, a vascular tube graft with an attached mechanical or biologic valve) to replace the proximal ascending aorta and the aortic valve. Circulation to the coronary arteries is maintained by implanting the proximal end of the coronary arteries into openings made in the aortic graft.

This procedure was first described by H. H. Bentall, MD, and A. DeBono, MD, in 1968(1) and still is performed today with some modifications. Currently, a full-thickness “button” of aorta surrounding the coronary ostia (ie, where the proximal coronary arteries attach to the aorta) is removed, making it easier to implant the proximal coronary arteries into the aortic vascular graft.

ANATOMY AND PHYSIOLOGY

The heart is a muscular, fourchambered pump that provides the power to move blood through the circulatory system. The heart is about the size of an adult’s fist, located slightly to the left of the midline of the mediastinum, directly behind the sternum (Figure 1). The four chambers of the heart consist of the right and left atria and ventricles. Oxygenated blood from the heart exits through the aorta to enter systemic circulation.2

The aorta exits from the left ventricle, arches upward and then down through the thorax and abdomen, and branches into the iliac arteries. The diaphragm separates the thoracic and abdominal portions of the aorta. The thoracic aorta is subdivided further into the ascending aorta, aortic arch, and descending aorta.3

The aorta is the largest artery in the body, and it supplies blood to all major arteries in the body. Like all arteries, the aorta consists of three layers: the tunica intima, the tunica media, and the tunica adventitia. The tunica intima is the innermost layer, consisting of endothelial cells and elastic tissues that give the aorta its elasticity and strength.3 The tunica media is the middle layer that contains smooth muscle tissue and elastic fibers. The tunica adventitia is the outermost layer, consisting of connective tissue.4 The aortic root includes the section of the ascending aorta that exits from the heart, the aortic valve, and the coronary ostia (ie, openings where the coronary arteries enter the aorta). The left and right main coronary arteries branch off from the ascending aorta to supply the heart muscle with oxygenated blood (Figure 2).

THE HEART VALVES. The purpose of the heart valves is to ensure that blood flows through the heart in one direction. The valves open and close passively, as a result of differences in the pressure gradients between the heart chambers. As blood accumulates in the heart’s chambers, the pressure behind the valve increases until it is greater than pressure beyond the valve. The valve opens allowing blood to flow through the valve and then closes as the pressure in front of the valve rises.” There are four heart valves: the aortic and pulmonic valves (ie, semilunar valves) and the mitral and tricuspid valves (ie, atrioventricular valves).s The mitral valve has two cusps; the other three valves are each composed of three cusps. The aortic valve is attached to the aortic wall and left ventricular muscle.”

THE CARDIAC CYCLE. The term cardiac cycle refers to the contraction and relaxation cycle of one heartbeat. An average cardiac cycle is about 0.8 seconds. Systole is the phase of the cardiac cycle associated with ventricular contraction and ejection of blood into systemic circulation, which accounts for one-third of the cardiac cycle. The atria contract to complete filling of the ventricles that began passively filling during systole. As the aortic and pulmonic valves open, the mitral and tricuspid valves close, producing the first heart sound, Sl. The aorta stretches and expands, temporarily storing a portion of the blood ejected from the ventricle.7

Diastole is the relaxation phase of the cardiac cycle, accounting for two-thirds of the cardiac cycle.” During diastole, blood from the lungs and systemic circulation enters the heart. Relaxation results in negative pressure that passively draws blood into the chambers of the heart. The mitral and tricuspid valves open, and the aortic and pulmonic valves close, which produces the second heart sound, S2. Blood enters the coronary arteries during this phase. The aorta recoils to propel blood into systemic circulation.9

Figure 1 * The heart is about the size of an adulfs fist, located slightly to the left of the mldllne of the mediastinum, directly behind the sternum.

Figure 2 * The aortic valve has three cusps. It is attached to the aortic wall and left ventricular muscle.

Figure 3 * An aneurysm of the aortic root is caused by degeneration of the tunica media.

PATHOPHYSIOLOGY

Aneurysms are classified by location and can affect any segment of the thoracic or abdominal aorta, singly or in combination.5 The terms aneurysm and dissection often are used interchangeably. Although both conditions may exist in the same patient, the terms describe two very different types of pathology.

AORTIC ANEURYSM. The term aortic aneurysm refers to a localized dilation of the wall of the aorta and generally is defined by an aortic diameter greater than 3 cm. Aortic aneurysms are caused by degeneration of the tunica media, causing dilation of all three layers of the artery.10 The wall of the aorta becomes progressively weaker as the aneurysm enlarges. If the aneurysm is left untreated, it may rupture and cause death from cardiac tamponade.3

There is a strong link between aortic aneurysms and atherosclerosis, although the relationship is not understood. It is theorized that the atherosclerotic process reduces the aortic wall’s elasticity in addition to thinning the wall of the vessel.11 One study found an autosomal dominant genetic connection in patients with thoracic aortic aneurysms.12 Twentyone percent of the study population (ie, patients who had a thoracic aneurysm or aortic dissection) had a close relative who had an aneurysm, either diagnosed or suspected due to sudden death with cardiac-like symptoms (eg, chest pain, shortness of breath, diaphoresis, nausea).

The term annuloaortic ectasia refers to an aneurysm of the aortic root accompanied by dilation of the annulus of the aortic valve and aortic valve incompetence as the result of cystic medial degeneration (ie, the tunica media of the aorta becomes less elastic as fibers break down). This may be a result of the aging process; hypertension; connective tissue disorders, such as Marian’s syndrome; or other unknown factors.5,11 Annuloaortic ectasia frequently is the indication for surgical aortic root replacement.

The pathologic changes in the ascending aorta can cause aneurysmal dilation of the aortic root (Figure 3), which can affect the ability of the aortic valve cusps to close, leading to valve incompetence and aortic regurgitation. When the aortic valve is incompetent, the valve fails to close completely, causing a backflow of blood into the heart from the aorta and increasing the workload of the left ventricle. Left ventricular hypertrophy may result from the increased workload and progress to left heart failure if the aortic regurgitation is not treated.9,13,14

AORTIC DISSECTION. The term aortic dissection refers to a tear in the intimai wall of the vessel, creating a false lumen that allows blood to accumulate between the tunica intima and the tunica media. Systemic blood pressure forces more blood into this false lumen with each heartbeat, enlarging the area of dissection. Untreated, the dissection will continue to enlarge, creating possible complications, such as

* aortic thrombus formation,

* compromised systemic circulation,

* rupture of the weakened aortic wall, or

* cardiac tamponade.

Patients may present with signs of shock because of decreased circulating blood volume or sudden onset of stroke or paralysis as a result of disruption of blood flow to the brain or spinal cord. Dissections of the ascending aorta may alter the normal anatomical structure of the aortic root, resulting in dysfunction of the aortic valve and disruption of the flow of blood to the coronary arteries.15-7

TABLE 1

Factors Associated with Developin\g Aortic Aneurysm and Aortic Dissection1-3

INCIDENCE. The incidence of all thoracic aneurysms is estimated to be 10.4 cases per 100,000 people annually.18 Thoracic aortic aneurysms occur most frequently in the ascending aorta (ie, 50%), whereas only 40% occur in the descending aorta, and the remaining 10% occur in the aortic arch.5,15 Aortic dissection affects two in 100,000 people in the United States annually, most commonly men who are 40 to 70 years of age.19 Factors associated with developing an aortic aneurysm or aortic dissection are presented in Table 1.

SYMPTOMS. Often thoracic aortic aneurysms are asymptomatic and are discovered only by testing for other conditions. Symptoms may not occur until the aneurysm grows large enough to compress adjacent structures in the chest, at which point patients may complain of chest or back pain.3,18 Symptoms specific to aortic root aneurysm caused by aortic regurgitation include

* cough,

* diastolic murmur,

* dysphasia,

* dyspnea on exertion,

* fatigue,

* orthopnea,

* palpitations,

* paroxysmal nocturnal dyspnea, and

* widened pulse pressures.5,20

Symptoms of aortic dissection include sudden onset of severe chest pain, which may radiate to the back and often is described as a “ripping” or “tearing-like” pain. Clinical signs of acute aortic insufficiency or aortic regurgitation resulting from an aortic root dissection are the same as those caused by aortic root aneurysm.16

DIAGNOSIS

Chest radiography may reveal an aortic aneurysm, usually by the presence of a widened mediastinum; however, it is not always possible to distinguish an aortic aneurysm from a mass. In some patients, an aortic root aneurysm might be obscured by the cardiac silhouette and therefore not be visible on a chest x-ray.9 Patients with aortic incompetence may have an enlarged cardiac silhouette.18 Transthoracic or transesophageal echocardiography can be used to diagnose pathology of the aortic valve and aorta. Contrast-enhanced computed tomography can be used to diagnose the presence, location, and size of an aortic aneurysm. Cardiac catheterization with aortography provides accurate diagnosis of the presence and severity of an aortic root aneurysm. If coronary artery disease is demonstrated during the cardiac catheterization, the surgeon probably will elect to perform a coronary artery bypass at the time of the aneurysm repair.9

Aortic aneurysms also may be detected during diagnostic testing for another condition. If the aneurysm is asymptomatic, the patient’s health care provider may recommend regular followup to monitor the aneurysm’s growth before proceeding with surgical repair. The consensus of many cardiothoracic surgeons is that elective surgery to repair the aneurysm is indicated for

* an aortic diameter greater than 4.5 cm in patients with Marian’s syndrome,

* an aortic diameter greater than 5.5 cm to 6 cm,

* any symptomatic aneurysm, or

* patients who have a family history of a ruptured aortic aneurysm.15,21

Elective surgery also is indicated if the patient has symptomatic aortic valve regurgitation related to the aneurysm. Rupture of the aneurysm requires emergency surgery to prevent death from cardiac tamponade or exsanguination.9

PREOPERATIVE PATIENT PREPARATION

At University Hospital, Birmingham, Ala, the patient is admitted to the hospital on the day before the scheduled procedure. Patients with a symptomatic aortic root aneurysm accompanied by a low ejection fraction (ie, less than 350%)22 may be admitted to the cardiac intensive care unit (CICU) for preoperative placement of an intra-aortic balloon pump (IABP). The IABP provides counterpulsation that reduces the workload of the heart during the night before surgery. The decision to use the IABP depends on the aneurysm’s location and structural involvement; however, this device must be used with caution in the presence of an aortic aneurysm.

Patient teaching and discharge planning begin on admission. The preoperative nurse gives the patient and his or her family members a hospitalprepared patient teaching booklet that outlines what to expect during the hospital stay, both preoperatively and postoperatively, and includes postdischarge instructions. This booklet contains a simplified description of basic cardiac anatomy and physiology. The different roles of hospital staff members who will care for the patient (eg, nurse practitioner, chaplain, dietitian, case manager, physical therapist) also are described. Equipment that will be used during the patient’s CICU stay is described in detail (Figure 4). This booklet also contains information that family members may need, such as parking, dining, and lodging options.

The preoperative nurse instructs the patient that nurses will be using a oneto-10 rating scale to frequently assess postoperative pain. The nurse also explains that the patient will be NPO after midnight the night before surgery. On the morning of surgery, the patient’s body hair will be removed with clippers, if needed, and the patient will be instructed to shower using antibacterial soap.

FIGURE 4

Excerpt from the Cardiovascular Surgery Patient Teaching Booklet

TABLE 2

Equipment and Supplies Needed for the Modified Bentall Procedure

PREPARATON OF THE OR

The circulating nurse and scrub person gather all equipment, supplies, instruments, and medications for the procedure (Table 2). The OR team prepares for femoral arterial and venous cannulation for cardiopulmonary bypass (CPB) to avoid the risk associated with cannulation of the aneurysm-weakened aorta.2 The circulating nurse checks the inventory of aortic root implants (Table 3) to ensure that all sizes of each implant that might be used are available.

The circulating nurse goes to the preoperative holding area to greet the patient and perform the preoperative nursing assessment. The circulating nurse introduces himself or herself to the patient and verifies the patient’s identity verbally and with the patient’s hospital identification bracelet. The nurse then verifies the surgical procedure with the patient and the consent form, ensuring that the written consent is in agreement with the patient’s statement of the planned procedure and the surgeon’s preoperative progress note. The circulating nurse questions the patient regarding allergies and NPO status and verifies that any dentures; partial dentures; contact lenses; and jewelry, including body jewelry, are removed before the patient’s transfer to the holding area. The nursing assessment also includes gathering all data relevant to the patient’s care, including

* the presence of any metal implants (eg, pacemakers, implanted defibrillators, total joint implants);

* sensory impairments;

* preexisting skin conditions; and

* any special positioning needs that the patient might have (eg, accommodating for the presence of joint contractures).

The nurse reviews the patient’s chart for relevant laboratory test results and the presence of a consent form for administration of blood products. Using information obtained during the preoperative assessment, the nurse formulates the appropriate nursing diagnoses and develops an intraoperative plan of care for the patient (Table 4). The anesthesia care provider administers preoperative IV antibiotics to the patient as ordered by the surgeon while the patient is in the holding area. To comply with infection control recommendations, antibiotic prophylaxis is administered within 60 minutes of the surgical skin incision.23

TABLE 3

Types of Grafts Used in Aortic Root Replacement

INTRAOPERATIVE PATIENT CARE

The circulating nurse and anesthesia care provider transfer the patient into the OR on either a stretcher or the CICU bed and help the patient move onto the OR bed. The circulating nurse offers the patient warm blankets for comfort and remains close to the patient during induction of anesthesia to offer emotional support to the patient and assistance to the anesthesia care provider. After anesthesia induction, the circulating nurse or the RN first assistant (RNFA) places an indwelling urinary catheter with a temperature probe. The surgeon and anesthesia care provider place pressure monitoring lines (ie, radial arterial line, central line, pulmonary artery catheter) for hemodynamic monitoring during the intraoperative and immediate postoperative periods. The circulating nurse places the patient’s wrist with the arterial line on a padded disposable arm board to help maintain the correct position of the arterial catheter.

The circulating nurse, surgeon, anesthesia care provider, and RNFA place the patient in the supine position for the procedure, ensuring that correct body alignment is maintained. The anesthesia care provider places the patient’s head on a padded headrest. The circulating nurse places an electrosurgical unit (ESU) dispersive pad under the patient’s upper back. If the patient has an implanted pacemaker or internal defibrillator, the ESU dispersive pad is placed at an alternate well-muscled site. The circulating nurse pads both of the patient’s arms at the elbows, and then rucks the patient’s arms at his or her sides using the draw sheet, with the palmar surface of the patient’s hands against the patient’s body. Padded sleds are used, if necessary, depending on the size of the patient.

SURGICAL PROCEDURE

The circulating nurse cleans the patient’s skin with an iodine/ alcohol solution from chin to toes, prepping both legs and feet circumferentially, taking care to avoid pooling of the prep solution. After the prep solution dries completely, the scrub person, RNFA, and surgeon drape the patient, and the scrub person passes the CPB pump lines off the field before the skin incision is made. The circulating nurse initiates a surgical “time out” in which all members of the surgical team participate, verifying the patient’s identity and scheduled surgical procedure before the skin incision.

TABLE 4

Nursing Care Plan for Patients Undergoing Aort\ic Root Replacement

The surgeon uses a #10-knife blade to make a midline incision extending from the supraclavicular notch to just beyond the xiphoid process. The surgeon places a rake retractor in the upper end of the incision to expose the sternal notch. He or she uses curved Mayo scissors to separate the tissue above the transverse ligament and then places a Shallcross clamp under the ligament, using the monopolar ESU pencil to transect the ligament.

The surgeon uses the ESU pencil to cut through the subcutaneous tissue and pectoralis muscle to the sternum. He or she uses the ESU pencil to mark the sternum down the midline to prepare for sawing.

Using an electrically powered sternal saw, the surgeon performs a median sternotomy. He or she then uses electrosurgery to obtain hemostasis of the sternal edges and soft tissue. The surgeon and RNFA place a four-bladed self-retaining sternal retractor between the sternal edges.

The surgeon uses a #10-knife blade to open the pericardial sac, then uses electrosurgery to complete the dissection. If necessary, the surgeon places a 2-0 silk pericardial stay stitch on the surgeon’s side of the chest to expose the aorta and secure the patient’s subcutaneous tissue.

At the same time the surgeon is making the midline skin incision, the RNFA uses a #10-knife blade to make an incision in the groin to expose the fmoral artery for cannulation. Cannulating the femoral artery makes the entire ascending aorta available for replacement if necessary. After exposing the femoral artery, the RNFA uses electrosurgery to dissect through the subcutaneous tissue and places a self-retaining Weitlaner retractor to expose the femoral artery.

The RNFA uses dissecting scissors to separate and expose the vessel and uses a single-armed 4-0 monofilament polypropylene suture with an RB-I needle as a purse-string stitch. The RNFA cuts off the needle and threads the suture through a disposable tourniquet and secures it with a hemostat with shods.

The surgeon places a purse-string stitch of 3-0 polypropylene suture with a polytetrafluoroethylene (ie, Teflon) pledget in the inferior vena cava for venous cannulation. He or she threads the pursestring stitch through a disposable tourniquet and uses a hemostat with shods to secure the tourniquet.

The surgeon then places a second purse-string stitch in the superior vena cava using a 3-0 single-armed polypropylene suture. He or she secures the purse-string suture with a tourniquet and hemostat with shods.

Before cannulation, the scrub person measures the bypass tubing, cuts it into appropriate lengths, and places a 1/2-inch by 3-inch by 8-inch Y-shaped connector on the venous side of the tubing. There is no need for an arterial connector, because the percutaneous arterial cannula has a built-in arterial connector.

The surgeon inserts an 18-gauge, hollow needle into the femoral artery until blood is returned. He or she then inserts a guide wire into the needle and advances it up the aorta. The surgeon removes the needle and threads a series of dilators over the wire and into the artery to dilate the artery for insertion of the cannula. He or she then threads the femoral artery cannula over the wire and inserts it into the femoral artery. When arterial blood enters the cannula, the surgeon places a pump clamp across the cannula, removes the wire, and connects the cannula to the arterial pump tubing. If air is present, the surgeon attaches a 60-mL syringe to the connector and removes the air via the syringe. The RNFA then secures the cannula to the patient’s leg using a threaded 0-silk suture.

Using a #ll-knife blade, the surgeon performs venous cannulation by making a stab wound in the inferior vena cava. If necessary, the surgeon uses a Kelly clamp to dilate the opening in the inferior vena cava and inserts a metal-tipped, rightangled femoral venous cannula. The surgeon tightens the tourniquet and secures it with a hemostat with shods. The surgeon ties a #2-silk suture around the cannula and the tourniquet to maintain proper cannula placement. The surgeon then cannulates the superior vena cava in the same manner. He or she connects these venous cannulas to the Y-shaped connector on the venous tubing and initiates CPB. After CPB has been established, the surgeon dissects around the aorta with dissecting scissors to separate it from the pulmonary artery.

The surgeon places a 3-0 polypropylene suture with a Teflon pledget in the proximal myocardial fat to allow the proximal aorta to be exposed and to establish the location of the coronary ostia. The surgeon cross-clamps the ascending aorta as close to the distal end as possible using an 35-degree-angled DeBakey peripheral vascular clamp.

The surgeon then inserts a cardioplegia needle into the ascending aorta and infuses cold sanguineous cardioplegia solution into the aortic root. Cold saline slush is applied topically to the heart to assist in myocardial protection.

When asystole is achieved, the surgeon incises the aorta transversely, proximal to the innominate artery. He or she then removes the excess tissue.

The surgeon inspects the aortic valve and the openings of the coronary ostia in regard to their position to the annulus. The surgeon detaches the coronary ostia from the aorta with rims of aortic tissue using dissecting scissors. Using the ESU pencil, the surgeon obtains hemostasis of the surrounding soft tissues and also mobilizes each coronary ostia. He or she places a 3-0 polypropylene suture in each ostia for retraction and secures them with hemostats.

The surgeon excises the aortic valve leaflets and uses metal sizers to measure the annulus. When the appropriate annulus implant size is established, the circulating nurse delivers an appropriately sized composite graft to the sterile field.

The surgeon inserts the proximal (ie, valved) end of the composite graft into the annulus. He or she then places a continuous 3-0 polypropylene suture over externally placed Teflon-felt strips to secure the valve portion of the composite graft into the aorta.

Figure 4 The surgeon implants each coronary ostia with rims of aortic tissue into the graft and then anastomoses the distal portion of the tube graft to the distal aorta.

The surgeon measures the graft for length and cuts it to the appropriate length. He or she manipulates the coronary ostia using the 3-0 polypropylene-stay stitches for placement into the graft.

The surgeon uses a #ll-knife blade to make a stab hole into the graft. He or she makes a circular opening with the #ll-knife blade and tenotomy scissors and removes excess graft. The surgeon then repeats the process for the other ostia. Using a continuous double- armed 6-0 polypropylene suture, the surgeon implants each coronary ostia into the graft at the transfer sites (Figure 4).

When coronary circulation has been reestablished, the surgeon cuts the distal portion of the tube graft or tailors it and anastomoses it to the distal aorta using a continuous 3-0 polypropylene suture over externally placed Teflonfelt strips.

Before making the final stitches, the surgeon infuses carbon dioxide into the left ventricle and the aortic tube graft to displace any air that is present in the heart. The surgeon releases the aortic cross clamp and, using echocardiogram guidance, removes air from the heart by gently squeezing and massaging the heart.

When the air is eliminated, the surgeon removes the cardioplegia needle and closes the hole with a 3-0 polypropylene suture with Teflon pledgets. For extra security, the surgeon then wraps the distal anastomosis with polyethylene terephthalate that was prepared from the residual tube graft.

The CPB is discontinued gradually, and the surgeon removes the femoral artery cannula. The anesthesia care provider administers a heparin antagonist to reverse the anticoagulant effect of the heparin administered for the CPB phase of the procedure.

The surgeon removes the superior vena cava cannula and ties down the purse-string suture. The surgeon connects the aortic tubing to the inferior vena cava cannula for infusion of the residual volume in the CPB machine.

The surgeon places three temporary pacing wires on the heart-two on the right atrium and one on the right ventricle. He or she places a straight, 28-Fr chest tube and an angled, 24-Fr chest tube into the patient’s mediastinum, and the scrub person connects them to a closed, chest-drainage system for postoperative monitoring.

The surgeon inspects the surgical sites for bleeding and makes any needed repairs. To ensure that the sternum is not bleeding, the surgeon removes the retractor and visually inspects the bone. The surgeon uses electrosurgery to stop any bleeding and then applies a paste to the bone, which aids in hemostasis. The surgeon places two surgical towels over the bone edges and replaces the sternal retractor in the chest.

When the volume in the CPB machine is infused, the surgeon removes the inferior vena cava cannula and ties down the purse- string suture. The surgeon examines all the cannulation sites as well as the anastomoses sites for bleeding. If no repairs are needed, he or she closes the patient’s chest using #7 steel sternal wires.

The surgeon closes the fascia and subcutaneous tissue with O polypropylene and 2-0 polypropylene sutures respectively. He or she then closes the skin with 4-0 polydioxanone suture. The RNFA applies a sterile dressing over the incision.

The anesthesia care provider and circulating nurse transfer the patient to the CICU accompanied by the surgeon and RNFA. During transfer, the anesthesia care provider continues to monitor the patient’s electrocardiogram (ECG), arterial pressure, and oxygen saturation with a portable monitoring unit and ventilates the patient using a bag/mask device and a portable oxygen tank.

POSTOPERATIVE CARE

On arrival in CICU, the circulating nurse and anesthesia care provider report to the postanesthesia care unit (P\ACU) nurse who will be caring for the patient. A respiratory therapist connects the patient to the ventilator. The PACU nurse continuously monitors the patient’s physiologic parameters, such as ECG, oxygen saturation, arterial pressure, and pulmonary artery pressure. He or she also monitors the patient’s arterial blood gases, chest tube drainage, and urinary output. Initially, all patients are ventilated mechanically, with weaning performed as tolerated. After extubation, the PACU nurse helps the patient with using an incentive spirometer and deep breathing and coughing every one to two hours to help prevent postoperative respiratory complications.

After 24 hours in the CICU, if the patient’s respiratory and hemodynamic status are stable, he or she may be transferred to the telemetry unit for the remainder of the hospitalization. If the patient had a mechanical valve implanted, the telemetry nurse starts the patient on prophylactic anticoagulation therapy when the patient is able to tolerate oral fluids and nutrition well. The telemetry nurse or a physical therapist assists the patient with progressive ambulation.

Before discharge from the hospital, the patient and his or her family members watch a videotape that explains the discharge instructions and are given the opportunity to ask any questions they may have about postdischarge care. Discharge instructions include

* progressively increasing activity as tolerated,

* avoiding vigorous activity for 12 weeks after surgery, and

* not lifting more than 5 lbs in the first two weeks and no more than 20 lbs for three months after discharge.

If the patient received a mechanical valve, he or she will require lifelong anticoagulation therapy. The goal is to maintain the international normalized ratio (INR) for anticoagulant monitoring between 2.5 and 3.5. Normal INR in an uncoagulated patient is 1.0.20

The telemetry nurse instructs the patient and his or her family members in the care of the incision, which includes cleansing the incision site daily with an antibacterial soap. The nurse also instructs the patient to report to the surgeon’s office immediately if he or she has any signs or symptoms of infection, including

* chills;

* drainage from the incision;

* fever (ie, temperature higher than 101 F [38.3 C]);

* incisional redness; or

* increased incisional tenderness.

The nurse instructs the patient to follow up with the cardiologist as well as the cardiothoracic surgeon who performed the procedure.

POSSIBLE COMPLICATIONS ASSOCIATED WITH THE BENTALL PROCEDURE

Patients undergoing the Bentall procedure may experience the complications associated with any cardiac surgery that involves CPB, including

* air embolus,

* arrhythmias,

* atelectasis,

* bleeding,

* pneumonia,

* transient confusion, or

* wound infections.

Potential complications specific to the Bentall procedure include

* graft infection,

* stoke caused by embolization of atherosclerotic plaques during surgery, or

* coronary insufficiency secondary to a coronary artery implanted into the graft becoming kinked.9

RESULTS

Research studies have demonstrated good overall patient outcomes after surgery for aortic root replacement, with with an average 86% long-term survival after the procedure.24,25 The postoperative outcome for these patients depends largely on their preoperative condition. Furthermore, patients undergoing elective aortic root replacement have demonstrated better outcomes than patients who underwent the procedure on an emergent basis.13

Patients who had a poor overall state of health before the procedure are referred to a cardiac rehabilitation program. The objective of the cardiac rehabilitation program is to help patients improve activity tolerance by building muscle strength and stamina and provide patient and family education in stress reduction skills and nutrition for heart health. This program also offers education and support for smoking cessation to patients who smoke.

Patiente who had a good overall state of health before the procedure tend to recover more quickly than do patients who were debilitated as a result of advanced age or preexisting comorbid conditions.24 Typically, younger patiente have better outcomes after aortic root replacement surgery than do older adult patiente.” Most patiente who are in good overall health before the surgical procedure are able to fully resume their normal preoperative level of activity within six to eight weeks after the procedure.24,26

Examination

The modified Bentall procedure for aortic root replacement

1. The terms aneurysm and dissection define similar pathology and can be used interchangeably.

a. true

b. false

2. Aortic aneurysms are caused by degeneration of the tunica

a. adventitia.

b. intima,

c. media.

3. Annuloaortic ectasia may be a result of

1. atherosclerosis.

2. hypertension.

3. connective tissue disorders, such as Marian’s syndrome.

4. the aging process.

a. 1 and 3

b. 2 and 4

c. 1, 2, and 3

d. 2, 3, and 4

4. Failure of the aortic valve to close completely, causing a backflow of blood into the heart from the aorta and increasing the workload of the left ventricle is called aortic

a. dissection,

b thrombus formation,

c. valve annulus dilation,

d. valve incompetence.

5. Symptoms specific to aortic root aneurysms caused by aortic regurgitation include

1. “ripping” or “tearing-like” chest pain.

2. diastolic murmur.

3. dysphasia.

4. orthopnea.

5. paroxysmal nocturnal dyspnea.

6. sudden severe chest pain.

a. 1, 3, and 5

b. 2, 4, and 6

c. 2, 3, 4, and 5

d. 1, 2, 3, 4, 5, and 6

6. A diagnosis of aortic aneurysm may be made by

1. cardiac catheterization with aortography.

2. chest radiography.

3. contrast-enhanced computed tomography.

4. transthoracic or transesophageal echocardiography.

a. 1 and 3

b. 2 and 4

c. 2, 3, and 4

d. 1, 2, 3, and 4

7. A composite graft may be a

a. homograft of the ascending aorta with tissue aortic valve,

b. mechanical valve with an attached woven tube vascular graft,

c. xenograft aortic root with valve.

8. The following nursing interventions are appropriate for the nursing diagnosis “Risk for alteration in tissue perfusion.”

1. Collaborates in fluid management.

2. Monitors physiological parameters.

3. Evaluates postoperative cardiac and peripheral tissue perfusion.

4. Identifies patient’s accepted postoperative pain threshold.

5. Identifies nominal hazard zone.

6. Assesses skin integrity, sensory impairments, and musculoskeletal status.

a. 1, 2, and 3

b. 4, 5, and 6

c 1, 3, 4, and 5

d. 1, 2, 3, 4, 5, and 6

9. Cold saline slush is applied topically to the heart to

a. assist in myocardial protection,

b. improve visibility of the surgical site,

c provide hemostasis.

10. To displace air that may be present in the heart, before making the final stitches, the surgeon

1. infuses carbon dioxide into the left ventricle and the aortic tube graft.

2. installs saline through the coronary bypass machine.

3. releases the aortic cross clamp and gently massages the heart.

a. 2

b. 1 and 3

c. 2 and 3

d. 1, 2, and 3

AORN is accredited os a provider of continuing nursing education by the American Nurses Credentiating Center’s Commission on Accreditation, AOKN is provider-approved by the California Board of Registered Nursing, Provider Number CEP 13019. Check with your state board of nursing for acceptance of this activity for retlcensure.

Learner Evaluation

The modified Bentall procedure for aortic root replacement

Objectives

To what extent were the following objectives of this Home Study Program achieved?

1. Discuss the pathophysiology of aortic abnormalities.

2. List diagnostic tools used to identify aortic abnormalities.

3. Discuss nursing care of a patient undergoing aortic root replacement surgery.

4. Describe the aortic root replacement surgical procedure.

Content

To what extent

5. did this article increase your knowledge of the subject matter?

6. was the content clear and organized?

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Purpose/Soak To educate perioperative nurses about caring for patients undergoing the modified Bentatl procedure for aortic root replacement.

Ifan aneurysm is asymptomatic, the patient’s health care provider may recommend regular follow-up to monitor the aneurysm’s growth before proceeding with surgical repair.

After using the electrosurgical pencil to cut through the subcutaneous tissue and pectoralis muscle, the surgeon marks the sternum down the midline in preparation for sawing.

The surgeon inspects the aortic valve and the openings of the coronary ostia in regard to their position to the annulus and then detaches the coronary ostia from the aorta with rims of aortic tissue.

If the patient received a mechanical valve, he or she will require lifelong anticoagulation therapy.

NOTES

1. H H Bentall, A DeBono, “A technique for complete replacement o\f the ascending aorta,” Thorax 23 (July 1968) 338-339.

2. J Rothrock, Alexander’s Care of the Patient in Surgery, 12th ed (St Louis: Mosby, 2003).

3. D Klein, “Thoracic aortic aneurysms,” Journal of Cardiovascular Nursing 20 (July/August 2005) 245-250.

4. L Copstead, J Banasik, Pathophysiology: Biological and Behavioral Perspectives, second ed (Philadelphia: W B Saunders Company, 2000) 367.

5. P C Seifert, Cardiac Surgery: Perioperative Patient Care (St Louis: C V Mosby, Inc, 2002).

6. D McGiffin, J K Kirklin, “Management of the small aortic root,” in Advanced Therapy in Cardiac Surgery, second ed, K Franco, E Verrier, eds (Hamilton, Ontario: B C Decker, 2003) 241-247.

7. R E Klabunde, Cardiovascular Physiology Concepts (Philadelphia: Lippincott Williams & Wilkins, 2005).

8. V Piacentino, “Cardiac physiology,” in Cardiothoracic Surgical Nursing Secrets, ed B A Todd (St Louis: C V Mosby, Inc, 2005) 11.

9. C Anderson, R Rizzo, L Cohn, “Ascending aortic aneurysms,” in Cardiac Surgery in the Adult, second ed, L H Edmunds, L Cohn, eds (New York: McGraw-Hill, 2003) 1123-1144.

10. E Tseng, M Comacho, “Thoracic aortic aneurysm,” eMedicine.com (Dec 6, 2005), http://www.emedkine.com/med/topic2783.htm (accessed 5 May 2006).

11. S Beese-Bjurstrom, “Hidden danger: Aortic aneurysms & dissections,” Nursinv2004 34 (February 2004) 3641.

12. J Elefteriades, “Natural history of thoracic aortic aneurysms: Indications for surgery and surgical versus nonsurgical risks,” Annals of Thoracic Surgery 74 (November 2002) S1879.

13. T David, “Surgery of the aortic root and ascending aorta, in Sabiston & Spencer Surgery of the Chest, vol 2, seventh ed, F Sellke, S Swanson, P Nido, eds (St Louis: Saunders, 2005) 1115- 1132.

14. B Todd, K Higgins, “Recognizing aortic and mitral valve disease,” Nursing2005 35 (June 2005) 58-63.

15. B Finkelmeier, Cardiothoracic Surgical Nursing, second ed (Philadelphia: Lippincott Williams & Wilkins, 2000).

16. K Shaughnessy, “Aortic dissection,” in Cardiothoracic Surgical Nursing secrets, ed B A Todd (St Louis: C V Mosby, Inc, 2005) 61-64.

17. L Scheetz, “Aortic dissection,” American Journal of Nursing 106 (April 2006) 56.

18. N Kouchoukos et al, Kirklin/Banatt-Boyes Cardiac Surgery: Morphology, Diagnostic Criteria, Natural History, Techniques, Results, and Indications, third ed (Philadelphia: Churchill Livingstone, 2003).

19. “Aortic dissection,” MedlinePlus Encyclopedia, http:/ fwww.nlm.nih.gov/medline plus/ency/artide/000181.htm (accessed 10 May 2006).

20. B A Todd, V P Addinizio, “Valvular heart disease,” in Cardiothoracic Surgical Nursing secrets, ed B A Todd (St Louis: C V Mosby, Inc, 2005) 52.

21. B Lytle, “Ascending aortic aneurysm,” in Operative Cardiac Surgery, fifth ed, T J Gardner, T L Spray, eds (London: A Hodder Arnold Publication, 2004) 435-442.

22. M Bolgna, personal communication with the author, Birmingham, Ala, 19 April 2006.

23. D Bratzler, P Houck, “Antimicrobial prophylaxis for surgery: An advisory statement from the National Surgical Infection Prevention Project,” Chnical Infectious Diseases 38 (June 15, 2004) 1706-1715.

24. E Prifti et al, “Early and long-term outcome in patients undergoing aortic root replacement with composite graft according to the BentalTs technique,” European Journal of Cardio-Thoracic Surgery 21 (January 2002) 15-21.

25. J Christensen et al, “Bentall procedure using cryopreserved valved aortic homografts: Mid- to late-term results,” Texas Heart Institute Journal 31 no 4 (2005) 390.

26. S Goldberg, personal communication with the author, Birmingham, Ala, 22 March 2006.

Cecile Cherry, RN; Starla DeBord, RN; Carol Hickey, RN

Cedle Cherry, RN, MSN, CNOR, is a nurse clinician in the cardiothoracic OR at University Hospital, Birmingham, Ala.

Starla DeBord, RN, BSN, is a nurse clinician in the cardiothoracic OR at University Hospital, Birmingham, Ala.

Carol Hickey, RN, MSN, is an education coordinator in the cardiothoracic OR at University Hospital, Birmingham, Ala.

The authors thank A. D. Padfico, MD, division director of cardiovascular/thoracic surgery at the University of Alabama at Birmingham, Birmingham, Ala; and Steven Goldberg, MD, resident in cardiothoracic surgery at the University Hospital, University of Alabama at Birmingham, for their assistance with preparing this manuscript.

Editor’s note: Teflon is a registered trademark of DuPont, Wilmington, Del.

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