1. Positive prospective crossmatch
2. Irreversible pulmonary hypertension (PVR ≥ 5 Wood units)
3. Malignancy
4. Uncontrolled active systemic infection
5. Severe obstructive or restrictive lung disease
6. Coexisting systemic disease
7. Severe cerebral and peripheral vascular disease
8. Severe cachexia
9. Long-standing diabetes with end-organ damage
10. Noncompliance with medications
11. Ongoing tobacco use, alcohol abuse, or drug addiction
12. Inability to fully understand procedure and participate in follow-up care
Table 26.2
Relative contraindications for heart transplantation
1. Age 70 or older |
2. Active myocarditis |
3. Graft failure due to acute rejection |
4. Recent systemic or other organ system infection |
5. Recent pulmonary/cerebral emboli |
6. Active gastrointestinal disease |
7. Obesity (BMI greater than 35) |
8. Irreversible renal dysfunction (may have combined heart-kidney transplant) |
9. Irreversible hepatic function (may have combined heart-liver transplant) |
Organ Allocation
In the United States, the United Network for Organ Sharing (UNOS) governs organ allocation. Heart allocation considers medical urgency, time on the waiting list, and the recipient’s blood type. Medical urgency categories include statuses 1A, 1B, 2, and 7 (◘ Table 26.3). The allocation algorithm is also modified by age so that adolescent donor hearts are preferentially used by pediatric recipients.
Table 26.3
UNOS medical urgency status categories for heart
1A. Patient has one of the following devices or conditions: |
(a) Left and/or right ventricular assist device |
(b) Total artificial heart |
(c) Intra-aortic balloon pump |
(d) Extracorporeal membrane oxygenation |
(e) Mechanical circulatory support with evidence of significant device-related complications |
(f) Mechanical ventilation |
(g) Continuous infusion of a single high-dose intravenous inotrope |
(h) Life expectancy <7 days |
IB. One of the following devices or conditions : |
(a) Left or right ventricular assist device |
(b) Continuous infusion of intravenous inotropes |
2. All other actively listed patients |
3. Patient is temporarily removed from active waiting list |
Donor Selection and Management
As with any organ donor assessment, the two most important goals are preventing disease transmission from the donor to the recipient and obtaining a graft that will adequately support the recipient’s function. Before the donor heart is fully evaluated for transplantation, the following donor conditions should be evaluated, as listed in ◘ Table 26.4.
Table 26.4
Donor heart exclusion criteria
1. Malignancy with extracranial metastatic potential |
2. Systemic sepsis or endocarditis |
3. Significant coronary artery disease |
4. Anatomic heart disease that will shorten the recipient’s expected lifespan |
5. Poor ventricular function |
Ideally, the donor is younger than 55 years of age with no history of chest trauma or cardiac disease and no prolonged hypotension or hypoxemia. Hemodynamically, the mean arterial blood pressure should be maintained above 60 mmHg and the central venous pressure (CVP) less than 15 mmHg. Inotropic support requirements should be less than 10 μg/kg/min of dopamine or dobutamine. Normal electrocardiograms and echocardiograms should be verified.
Coronary angiography should be performed for donors with cardiac risk factors to rule out coronary artery disease. If donor myocardium insult is suspected, troponin should be measured and, occasionally, the left ventricular end diastolic pressure (LVEDP), to assess any underlying myocardium stiffness or diastolic impairment, despite a normal systolic function on the echocardiogram.
Most donors who have suffered acute brain injury will display some hemodynamic instability from neurologic shock, which may cause excessive fluid losses and bradycardia, or even transient depression of cardiac function. The donor may require intravenous vasopressin to keep up with excessive urine losses caused by diabetes insipidus. Hormonal therapy includes the use of thyroxine, cortisol, and antidiuretic hormone—and insulin may also be necessary. Sometimes, serial echocardiograms may be needed to show recovered cardiac function if the initial echocardiogram showed decreased ventricular function.
Due to a donor organ shortage, liberalizing certain donor selection criteria has been gaining favor. So-called marginal donor hearts, such as those from older donors, donor hearts with longer ischemic time, or donor hearts with mild left ventricular hypertrophy, mild valvular abnormalities, or mild coronary artery disease, have been successfully used. Concomitant coronary bypass grafting and valve repairs have been performed on donor hearts during the heart transplant procedure.
Certain strategies have been used to select the donor who best meets the recipient’s functional demand. Typical acceptable donor weight ranges are between 70 and 130 % of the recipient’s weight [6]. But for recipients with increased pulmonary vascular resistance (PVR) and with prior cardiac surgeries, it is often prudent to use a larger donor, preferably a male donor for a female recipient. Maximizing donor heart preservation during organ retrieval is also important. This includes the use of hypothermia, cardioplegia, and various preservation solutions that may contain antioxidant additives to help prevent reperfusion injury. More recently, an organ preservation device that provides continuous perfusion of myocardium with warm donor blood is used during transport of the heart. With this system, the donor heart remains beating during the transport. A completed multicenter clinical trial showed the system safe and efficient [7].
Preparation of the Recipient
The preparation of transplant patients should be started early—similar to the time needed to prepare patients for high-risk coronary artery bypass grafting (CABG ), valve repair, or valve replacement surgery. Every single step of surgery should be well thought out and planned in anticipation of the impending heart transplant (◘ Fig. 26.1). It is needed even more so than during ventricular assist device implantation procedure.
Fig. 26.1
Recipient operation setup. An overall setup similar for other open heart operations is adequate. Perioperative medications include the administration of antibiotics (usually first-generation cephalosporins) and immunosuppression agents. The recipient is usually intubated after confirmation that the donor heart is suitable for transplantation. A Foley urine catheter and a Swan-Ganz catheter are placed. Although all heart transplant patients on the waiting list would have had a right heart catheterization during their initial evaluation, determining their PA pressures following intubation might influence the need for peri- and postoperative pulmonary vasodilator therapy such as nitric oxide. Reprinted with permission from John R, Liao K. Orthotopic heart transplantation. Operative Techniques in Thoracic and Cardiovascular Surgery 2010; 15:138–146
The initial aortic cannulation site should be as distal as possible, allowing ample room between the aortic cannulation site and the proximal vein graft anastomosis or aortotomy incision. This provides room for the aortic cross-clamping and normal aortic tissue when sewing the anastomosis during the heart transplant. The use of suture pledgets on the aorta should be avoided, if possible, because dense tissue adhesions or scarring can occur around pledgets. Single-stage superior vena cava (SVC) and inferior vena cava (IVC) venous cannulation should be avoided, when possible, to preserve anatomy around the cava and to minimize scarring and stenosis of the SVC, especially when automatic implantable cardioverter-defibrillator (AICD) or pacemaker leads are present. In multiple redo patients, a colored elastic vessel loop is placed around the ascending aorta and left inside the mediastinum to be used as a landmark for easy dissection of the ascending aorta during transplant. With more and more transplant patients receiving left ventricular assist device (LVAD) support prior to transplant, the following strategies are used in our center to make chest reentry and LVAD explantation safe and expeditious: The LVAD outflow graft is kept relatively long and placed into the right pleural space to avoid reentry injury to the graft. A Gore-Tex mesh is placed behind the sternum to cover the right ventricle and LVAD outflow graft to avoid reentry injury to the right ventricle and/or the LVAD outflow graft. It is helpful to obtain a computed tomography (CT) scan of the chest to assess the proximity of the heart or other critical structures (e.g., the LVAD outflow graft) to the undersurface of the sternum.
Once donor availability is confirmed, the recipient is admitted to the hospital. Clinicians take a pertinent medical history, perform a physical examination, and order routine blood tests. Special attention is paid to double-checking donor and recipient blood types and crossmatching results. The patient’s current status of infection and anticoagulation should be assessed and addressed with appropriate antibiotics and blood product transfusion, if time allows. If the patient had a mechanical ventricular assist device recently implanted for acute myocardial infarction, the heart may not have time to dilate and the pericardial space can be small due to decompression by the device. It is important to review the patient’s current chest X-ray or CT scan to have a realistic estimation of the recipient’s pericardial space to avoid donor and recipient heart size mismatch. Comparing the ratio of cardiac silhouette dimension to chest wall dimension, in addition to a height comparison between the donor and recipient, can be very useful objective measurements.
Intraoperative Monitoring
The recipient receives a radial artery line and a Swan-Ganz catheter. The catheter is usually placed via the left internal jugular vein. This approach is used to preserve the right internal jugular vein route for postoperative transvenous endomyocardial biopsies. However, for a patient with AICD and pacemaker leads, a right internal jugular approach is used to avoid resistance. Pulmonary artery pressure is first measured and then the catheter tip is pulled back into the superior vena cava before the recipient cardiectomy is performed. A transesophageal echocardiography (TEE) probe is routinely placed only to be used later to assess the donor heart contractility and volume status and to help remove air from cardiac chambers.
In patients requiring redo sternotomy, external defibrillator pads are placed in case of ventricular fibrillation during early mediastinal dissection, and a femoral arterial catheter is placed for quick establishment of femoral-femoral cardiopulmonary bypass support should injury to the heart occur during entry to the mediastinum.
Timing of Donor and Recipient Operations
Most research data has shown that the donor heart will tolerate ex vivo cold preservation of 4–6 h. It is common practice that all measures are taken to limit the donor heart ischemic time to less than 6 h. Particularly when the recipient has an elevated pulmonary artery pressure or the donor heart is from a marginal donor, or there is a donor and recipient weight discrepancy, it is highly advantageous to achieve reperfusion in the shortest possible time to allow optimal right ventricular function. Coordination of the donor and recipient operations is key to shortening the donor ex vivo ischemic time.
The following factors must be considered when estimating the donor heart ex vivo ischemic time: (1) the time that other organ procurement teams need to complete their dissection before donor heart cross-clamping, especially when multiple organs are procured, (2) organ transportation time, (3) anticipated difficulty of monitoring line insertion and anesthetic induction, and (4) anticipated difficulty of accessing the heart in a recipient who had previous cardiac surgical procedures and, specifically, when he or she is supported by an intracorporeal LVAD. Within these confines, attempts are made to effectively coordinate every single step to minimize waiting periods in the recipient operating room and minimize time on cardiopulmonary bypass support. When the donor heart has safely arrived in the region of the recipient’s hospital, cardiopulmonary bypass begins. Recipient cardiectomy is performed only when the donor heart arrives in the operating room and is inspected by the transplant surgeon. In recent years in our practice, we have seen increased numbers of recipients with multiple cardiac operations and with ventricular assist device support. Importantly, we’d rather have the recipient ready and wait for the donor heart to arrive than the other way around.
It should be noted that no incision is made in the recipient until the retrieving surgeon is satisfied with the donor heart, and no cardiectomy is performed until the donor heart arrives in the recipient’s operating room.
Donor Heart Procurement
Donor heart procurement is performed through a median sternotomy. The pericardium is opened widely. The heart is inspected for any signs of trauma, infection, or congenital anomalies. Overall contractility of both the left and right ventricles is appreciated. The four chambers of the heart are palpated to detect any valve or vessel pathology-related thrills. The coronary arteries are palpated to rule out any evidence of coronary artery disease. The ascending aorta is separated from the pulmonary artery. The superior vena cava is mobilized circumferentially up to and beyond the level of the azygos vein and encircled with two heavy ties of 0 silk sutures. The inferior vena cava likewise is mobilized circumferentially and surrounded with a vessel loop.
At least 300 units of heparin/kg of donor weight are administered intravenously to the donor. A cardioplegia needle is inserted into the ascending aorta. Venous return to the heart is interrupted by dividing the SVC between the two silk ties. The IVC is divided flush with the diaphragm. The tip of the left atrial appendage is amputated. The ascending aorta is cross-clamped and about 2 L of cold cardioplegia is administered into the ascending aorta. Ice slush is immediately poured into the pericardial space and onto the heart to provide rapid topical cooling. Once cardiac arrest is achieved, the heart is excised in an expedient fashion. First, the pulmonary veins are divided flush with the pericardium. The aorta is divided as distal as possible, usually at the takeoff of the innominate artery , and the main pulmonary artery is divided at its bifurcation. If the recipient requires reconstruction of both pulmonary arteries, then the branch pulmonary arteries are divided at the level of the pulmonary hilum. Additional length of the ascending aorta may be required for recipients with hypoplastic left heart syndrome or with L-transposition of the great vessels.
Recipient Cardiectomy [8, 9]
Incision and Establishment of Cardiopulmonary Bypass
A median sternotomy is performed in all recipients. In patients who have had a previous cardiac surgical procedure, particularly if multiple ones, or if the hemodynamic status is precarious or the heart is severely dilated, it is wise to isolate both the femoral artery and vein so that rapid femoral-femoral bypass can be instituted should circulatory decompensation or uncontrollable bleeding occur. After the skin and subcutaneous tissue incision, the sternal wires are cut but not pulled. An oscillating saw is used to cut the sternum’s anterior plate and stopped when the saw hits the wires. The wires are then pulled out and the sternum’s posterior is cut with a pair of straight Mayo scissors while the sternum is lifted up with bone hooks and the ventilator is put on hold.
In patients with no previous cardiac surgical procedures, the pericardium is opened and secured to the sternotomy edges with sutures. The aorta and pulmonary artery are separated using electrocautery. After systemic heparin infusion, the purse-string sutures are placed in the ascending aorta and right atrium or vena cava. The ascending aorta is cannulated in routine fashion just proximal to the innominate artery. The cannula size varies from 20 French to 24 French, depending on the recipient’s body weight. Venous cannulation differs depending on whether the patient has a previous AICD/pacemaker lead placement or scarring and whether the surgeon will use a biatrial or bicaval anastomosis. If the patient has no AICD/pacemaker leads or has a dilated superior vena cava or a bicaval anastomosis is to be performed, a right-angle 32 French cannula, if possible, is inserted directly into the SVC. Otherwise, a straight venous cannula is placed posteriorly in the right atrium near the orifice of the SVC and advanced into the SVC. The inferior vena cava cannula, preferably a 36 French size, is inserted posteriorly in the right atrium near the IVC orifice. The cavae are then encircled with Rommel tourniquets to allow institutions of total bypass. The choice of caval cannulation sites must allow a generous cuff of posterior atrium for biatrial anastomosis and a generous atrial cuff of both SVC and IVC for bicaval anastomosis (◘ Fig. 26.2).
Fig. 26.2
Recipient cardiectomy. Recipient cardiectomy is usually performed such that it is completed at the same time that the donor heart arrives in the operating room. The patient is placed on cardiopulmonary bypass; the aorta is cross-clamped and the caval snares are tightened. The aorta and the pulmonary artery are separated and the interatrial groove is developed. The great vessels are divided just distal to their respective valves. The superior vena cava is transected at the cavo-atrial junction. A large cuff of IVC is prepared by transecting the right atrium adjacent to the IVC (this incision is ideally made by carrying it medially through the ostium of the coronary sinus and laterally through the floor of the fossa ovalis). The left atrial cuff is prepared by entering the roof of the left atrium (this is facilitated by the development of the interatrial groove); this incision is extended to leave behind a generous cuff of posterior left atrial tissue while observing the orifices of the four pulmonary veins. The left atrial appendage is also usually excised. Reprinted with permission from John R, Liao K. Orthotopic heart transplantation. Operative Techniques in Thoracic and Cardiovascular Surgery 2010; 15:138–146
In patients with redo sternotomies, the aorta and right atrium are first isolated so that cardiopulmonary bypass support can be readily established in case of unstable hemodynamics during the cardiac dissection. Sometimes it is necessary to place the patient on the bypass to facilitate safe and expeditious dissection, especially in patients with previous coronary artery bypass grafting surgery and with patent grafts. The attempt is made in all cases to avoid systemic heparinization and the start of cardiopulmonary bypass for as long as reasonably possible—to lessen the period of bypass and attendant bleeding complications. A metal-tip aortic cannula is used for all the redo aortic cannulations to make penetration easy through scar tissues .
In patients with LVAD or Bi-VAD implantation , the entry to the mediastinum should be as cautious as with the other redo sternotomies, if not more. The injury to the LVAD outflow graft can result in a large amount of blood loss in a short period of time, and quick hemodynamic compromise because of its high intraluminal pressure. After starting the technique to place the LVAD outflow graft in the left pleural space, injury to the graft is completely avoided during reentry to the mediastinum. With the HeartMate LVAD, the Thoratec Company developed a Gore-Tex outer graft to protect the inner Dacron graft from being injured and to reduce adhesions around the Dacron graft so that its removal is easier. The Gore-Tex outer graft is also a useful landmark to trace to the proximal ascending aorta. Once the patient is placed on cardiopulmonary bypass support, both LVAD and right ventricular assist device (RVAD) can be turned off. Once the donor heart arrives at the hospital, the LVAD outflow graft can be divided and the RVAD inflow cannula and outflow graft can be removed and divided, respectively.
Once the donor heart arrives on the grounds and is being returned to the recipient hospital by ambulance, the patient is placed on cardiopulmonary bypass, and the body temperature is cooled to 28 °C.
Excision of Recipient Heart (◘ Fig. 26.2)
The distal aorta is cross-clamped. Excision of the diseased heart begins at the lateral right atrial wall. The right atrium is entered at the midpoint, 2–3 cm anterior to the caval cannulae. This excision is extended inferiorly toward the coronary sinus. Superiorly, this incision is extended around the superior aspect of the right atrium and to the aortic root at the level of the noncoronary sinus. The aorta and pulmonary artery are divided at the level of their respective semilunar valves. The interatrial septum is then entered at the anterior portion of the fossa ovale close to the tricuspid valve. The incision is extended superiorly to the left atrial roof and inferiorly, staying close to the atrioventricular groove. The heart is then pulled upward and toward the right side. The remaining attachments of the left atrial are divided close to the atrioventricular groove to leave a generous cuff of the posterior left atrium anterior to the pulmonary veins. The aorta and pulmonary artery are separated using electrocautery. Care must be taken to avoid injury to the right pulmonary artery during this maneuver. The recipient left atrial cuff may be trimmed appropriately based on the size of the donor left atrium to lessen their size discrepancy.
If a bicaval anastomosis technique is used, the SVC and IVC are cannulated as distally as possible. The heart is first excised in the standard fashion, leaving the posterior aspect of the left atrium and the posterolateral aspect of the right atrium. The right atrium is then excised so as to leave 2–3 cm of atrial cuff around each cava.
A small endotracheal suction catheter which insufflates continuous carbon dioxide (CO2) is anchored to the pericardial sac. The gravity of CO2 is heavier than that of the air, and it is used to expel air from the open cardiac chambers. CO2 is readily absorbed by the blood and forms no air bubbles. The perfusionist should pay special attention to the blood PH and CO2 level to adjust the CO2 flow rate and prevent acidosis.
Implantation of the Donor Heart [8–10]
Donor Heart Preparation
The donor heart is prepared as follows: Using electrocautery, the aorta and pulmonary arteries are separated and the posterior pulmonary artery attachments to the left atrium are divided. The left atrial cuff is created by connecting incisions between each of the four pulmonary veins and excising the posterior atrial wall. The fossa ovalis is inspected. If a patent foramen ovale or a septal defect is present, it is over-sewn with a 4-0 Prolene suture. If biatrial anastomoses are planned, the inferior vena cava is opened curvilinearly toward the right atrial appendage to avoid the sinoatrial node. The SVC is closed circumferentially (◘ Fig. 26.3).
Fig. 26.3
Preparation of the donor heart . The aorta and pulmonary arteries are separated and the posterior pulmonary artery attachments to the left atrium are divided. The left atrial cuff is created by connecting incisions between each of the four pulmonary veins and trimming excess tissue to create a smooth continuous edge. The fossa ovalis is inspected and probed to identify a patent foramen ovale, which can be closed by a continuous 4-0 Prolene suture from the right atrial side. For the bicaval technique, the recipient cuff is present. For the biatrial technique, the SVC is doubly ligated, and the right atrium is opened from the lateral IVC toward the right atrial appendage, to avoid the sinus node. Ao = aorta, IVC = inferior vena cava, LA = left atrium, SVC = superior vena cava. Reprinted with permission from John R, Liao K. Orthotopic heart transplantation. Operative Techniques in Thoracic and Cardiovascular Surgery 2010; 15:138–146
A retrograde cardioplegic catheter is inserted into the coronary sinus and a dose of 400 cm3 cold blood cardioplegia is infused. The infusion of retrograde cardioplegia before implanting the donor heart has the following potential benefits: (1) it provides nutrients to the heart before it sustains an extra 30–60 min of ischemia; (2) it can expel the debris and air trapped inside the donor coronary arteries that occurred during harvesting and the transportation process; and (3) it may improve the initial recovery of transplanted hearts.
Left Atrial Anastomosis
Left atrial anastomosis is begun at the base of the left atrial appendage near the left superior pulmonary vein using a long 3-0 Prolene suture. The initial couple of sutures are placed with the donor heart resting on the left sternal edge. The heart is then lowered into the recipient pericardium. A dry 4 × 4 sponge is placed inside the left atrium cavity to prevent debris from falling into pulmonary veins during anastomosis. The two ends of suture are run inferiorly and superiorly and eventually joined in the middle of the interatrial septum. The sponge is then removed. The left atrium is filled with cold saline and the lungs are ventilated to expel the air before the sutures are tied. To minimize the chance of left atrial thrombosis formation, we use an everting suture technique to approximate smooth endocardial surfaces of the donor’s and recipient’s left atrium and avoid rough tissue surface exposure to blood.
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