Operative technique for heart-lung transplantation

J

THoRAc CARDIOVASC SURG

87:930-935, 1984

Current Technique

Operative technique for heart-lung transplantation Combined heart and lung ~plantation has now been carried out in 17 patients at Stanford University Hospital. The emphasis on the management of donors is upon thorough tracheobronchial toilet and ensuring an absence of significant cardiopulmonary disease. The most important aspects of the recipient operation are to remove the heart and lungs without injury to the phrenic, vagus, or recurrent laryngeal nerves and to ensure hemostasis. This is best effected if the heart and lungs are removed separately. The operative technique for both the donor and recipient is described.

Stuart W. Jamieson, M.D., Edward B. Stinson, M.D., Philip E. Oyer, M.D., John C. Baldwin, M.D., and Norman E. Shumway, M.D., Stanford. Calif.

Combined heart and lung transplantation has been shown to provide successful therapy for patients with end-stage heart and lung disease. Many patients with cardiac disease are not treatable by isolated heart transplantation because of pulmonary hypertension, which acutely imposes an unacceptable workload upon the normal donor right ventricle. Further, patients with isolated end-stage pulmonary disease, with or without cor pulmonale, may be more satisfactorily treated by heart and lung transplantation than by lung transplantation alone; the heart-lung operation removes all diseased tissue, and the coronary-bronchial anastomoses are left intact, so that there is immediate blood supply to both sides of the airway (tracheal) anastomosis. An additional advantage is that assessment of rejection of the entire heart and lung graft may be made by cardiac biopsy. Seventeen heart-lung transplant operations have now been performed at Stanford University. Changes in technique have been made since the program began, and From the Department of Cardiovascular Surgery, Stanford University Hospital, Stanford, Calif. Supported in part by a grant from the National Institutes of Health, HLl3I08. Received for publication Dec. 19, 1983. Accepted for publication Jan. 10, 1984. Address for reprints: Stuart W. Jamieson, M.B., F.R.C.S., Assistant Professor, Cardiovascular Surgery, Stanford Medical Center, Stanford, Calif. 94305.

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this paper describes the technical aspects of the procedure as it is now performed.

The donor Suitable donors for heart-lung transplantation are scarce, because of the tendency for brain-dead and intubated patients to have early pulmonary infections and other abnormalities. However, with careful attention to pulmonary toilet and the avoidance of high inspired oxygen levels and excessive infusion of fluids, potential donors can be maintained in good condition. We have used lungs for transplantation after 5 days of intubation. The donor should be intubated with a high-eompliance, high-volume, low-pressure endotracheal tube, connected to a volume-cycled respirator, and ventilated with an inspired oxygen fraction (Fl o2) of 40% or less. It is useful to use a size 8 or 9 tube so that endoscopic bronchoscopy can be performed if necessary. The addition of 3 to 5 em H 20 of positiveend-expiratory pressure (PEEP) with intermittent "sighing" helps to prevent alveolar collapse. Suitable donors obviouslycannot have sustained significant thoracic trauma and must have a clear chest roentgenogram. The arterial oxygen tension on an FI02 of 40% should be >90 torr. The central venous pressure should be maintained as low as possible (below 10 em H 20) to help prevent neurogenic pulmonary edema. A nasogastric sump tube is connected to continuous wall suction at 8 to 12 em H 20. The mean arterial pressure should be maintained

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Heart-lung transplantation

June 1984

between 70 and 80 mm Hg, and fluid should be replaced with Ringer's lactate solution at a rate of 25 to 100 ml/hr added to the previous hour's urine output. Metaraminol, 100 mg in 500 mI of 5% dextrose in water, is given as required to maintain the mean arterial pressure. Diabetes insipidus may necessitate the administration of vasopressin, 10 to 20 units intravenously every 1 to 6 hours, as required, if the urine output exceeds 200

ml/hr, We believe that extracorporeal preservation of the lung for periods greater than 2 hours is not safe with current techniques. Therefore, only "on site" donors are used. It nearly always is necessary to transport the body from a distant hospital. During transportation manual ventilation is used and frequent endotracheal suction is performed. The donor operation At the beginning of the operation the donor is given methylprednisolone, 30 mg/kg, intravenously. Throughout the donor operation it is important to handle the lungs gently and as infrequently as possible. A median sternotomy is performed, followed by a complete anterior pericardiectomy, including both phrenic nerves and the thymus or thymic remnants. The ascending aorta, the innominate artery, and both venae cavae are dissected free and encircled with umbilical tapes. The azygos vein is doubly ligated and divided. The trachea is encircled with a tape as high as possible, without dissection of peritracheal tissue in the immediate supracarina1 region. Heparin is administered (300 units/kg, intravenously). The heart is arrested with cardioplegic solution in the usual fashion. The lungs are perfused with a modified Collins' solution (12 mEq of MgS04 and 65 ml of 50% dextrose added per liter), which is infused at 4 C through an in-line (5 f.L) filter via a No. 14 Fr. sump catheter inserted in the main pulmonary artery. The pressure in the pulmonary artery should not exceed 20 mm Hg. The superior vena cava is doubly ligated and divided. The inferior vena cava is then cut. The heart is allowed to empty and the aorta then is cross-clamped. Both infusion solutions are begun. It is important to continue gentle ventilation, to promote even distribution of the cold infusion. The tip of the left atrial appendage is amputated to allow egress of the fluid from the pulmonary circulation and thus prevent distention of the left cardiac chambers and pulmonary vasculature. Cardioplegic solution, 500 mI, is administered, and the pulmonary infusion is continued to a total of 20 ml/kg of body weight. Topical cold Ringer's solution is applied to both the heart and lungs. 0

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The aorta is divided at the level of the innominate artery and the heart and lungs are removed by dividing the posterior pleural reflections and pulmonary ligaments. The trachea is clamped at least 5 rings above the carina while the lungs are held inflated. The trachea is divided above the clamp. The heart-lung bloc is then placed into a sterile basin containing Ringer's solution at 4 C and transferred to the recipient operating room. 0

The recipient The most important aspects of the recipient operation are to remove the heart and lungs without injury to the phrenic, vagus, or recurrent laryngeal nerves and to ensure hemostasis. All blood and blood products should be administered through a 20 f.L filter. A standard median sternotomy is performed. Prior to heparinization and cannulation, incisions are made into both pleural cavities by dividing the pleura anterior to the pericardium, and the lungs are palpated to ensure that they are free of adhesions. If possible, any adhesions should be taken down with electrocautery prior to heparinization and the commencement of bypass, although this may be difficult because of cardiomegaly. The pericardium is incised anteriorly in the midline. The thymic fat pad is removed, but care should be taken not to injure the phrenic nerves which course anteriorly near the innominate vein. Cannulation high in the aorta is carried out, followed by cannulation of the superior and inferior venae cavae through the right atrium. After initiation of bypass, these vessels are snared, the aorta cross-clamped, and the heart removed. This is effected by transection of the aorta at the level of the aortic valve commissures and the main pulmonary artery at its mid-point and by incision of the right and left atria at the atrioventricular junctions, though both appendages are removed. The anterior left pericardium is now excised, with a margin of approximately 3 em left anterior to the left phrenic nerve. An incision is then made posterior to the left phrenic nerve immediately anterior to the pulmonary veins (Fig. I, A). This incision passes down as far as the diaphragm and upward as far as the left pulmonary artery. A vertical incision, separating the left pulmonary veins, is now made through the oblique sinus of the left atrium. These veins are now freed from the posterior mediastinum, with care being taken to preserve the left vagus nerve, which lies immediately posteriorly on the esophagus (Fig. 1, B). The left pulmonary ligament is divided, and the left lung is now retracted up out of the wound anteriorly and toward the right; electrocautery is

932 Jamieson et al.

The Journal of Thoracic and Cardiovascular Surgery

Fig. 1. A, The recipient atria after removal of the heart. Incisions are made so as to preserve the phrenic nerve in a " ribbon" of pericardium. The left and right pulmonary veins are separated by a longitudinal incision in the posterior left atrial wall and thus into the oblique sinus. Do The left pulmonary veins are withdrawn beneath the phrenic nerve. The vagus nerve is immediately posterior. Co The left lung is progressively mobilized, and the bronchial arteries are secured. Do The left pulmonary artery is divided and the bronchus is stapled and cut. (Copyright B. Hyams.)

used to separate the remaining pleura posteriorly so as to free the entire hilum. Several large bronchial arteries will be found, especially in patients with Eisenmenger's syndrome. These are individually secured with clips (Fig. 1, C). The bronchus is now exposed. It is retracted well out toward the right and freed from surrounding tissue and bronchial arteries . The pulmonary artery here is transected. A TA 30 stapler with 3.5 mm staples is

used to clamp the left bronchus (Fig. 1, D) . The left bronchus is now cut distal to the staples, and the left lung is passed off the table. It should be considered unsterile, together with the instruments used in cutting the bronchus. Attention is now turned to the right lung. Excess pericardium anterior to the right phrenic nerve is removed. A further incision is made posterior to the

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Fig. 2. A. The right phrenic nerve is separated from the hilum. B. The right pulmonary veins are separated from the right atrium. C, The right pulmonary ligament is divided, the lung is mobilized, and the pulmonary artery and bronchus are cut. D. The remnants of the pulmonary artery are removed, leaving the area around the ductus ligament and recurrent nerve. The trachea and bronchial remnants are exposed to the right of the aorta. The trachea is cut just above the carina. (Copyright B. Hyams.)

phrenic nerve, which lies closer to the hilum than on the left. When the hilum is reached, the pericardium is retracted to the left, and again a 3 em pericardial ribbon containing the phrenic nerve is fashioned from the pulmonary artery to the diaphragm (Fig. 2, A). As the phrenic nerve proceeds cephalad over the pulmonary artery, it lies surprisingly anterior over the superior vena cava. The left atrium is now incised longitudinally, as though to expose the mitral valve. This incision can be

carried superiorly and inferiorly, with the result that the right atrium is freed from the pulmonary veins (Fig. 2, B). Care should be taken not to "button-hole" the septum, which will form the posterior aspect of the new right atrium. The right pulmonary ligament is now divided, and the right lung is withdrawn out of the chest. The posterior pleura is divided with electrocautery, with care again taken not to injure the vagus nerve. The right lung now remains attached only by the right bronchus

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The Journal of Thoracic and Cardiovascular Surgery

Fig. 3. Reimplantation: A. The right lung passes beneath the right atrial remnant and the phrenic nerve. B. The tracheal anastomosis is performed first, commencing with the posterior wall. C. The right atrial anastomosis. D. The aortic anastomosis. (Copyright B. Hyams.)

and right pulmonary artery : These are divided (Fig. 2, e), the bronchial arteries are secured, and the bronchus is stapled. The remnants of the pulmonary artery are now removed, with a small segment left around the ductus ligament so as to preserve the recurrent laryngeal nerve. The trachea is exposed to the right of the aorta (Fig. 2, D). The stumps of the left and right bronchi can be retracted toward the midline; the left is longer than the right. Care should be taken to leave the surrounding blood supply to the trachea as intact as possible. A large

bronchial artery generally lies posterior to the trachea and should be ligated here. The trachea is cut immediately above the carina. The donor heart and lungs are passed onto the field. The donor trachea is trimmed immediately above the carina. Cultures are taken from the donor trachea, which is then suetioned thoroughly though gently. The right lung is passed beneath the right atrium and phrenic nerve pedicle (Fig. 3, A), and the left lung is passed beneath the left phrenic nerve. The tracheal anastomosis is performed with continuous 3-0 polypropylene suture, commencing with the

Volume 87 Number 6 June 1984

posterior aspect (Fig. 3, B). If there is a size difference, this is made up on the membranous portion of the trachea. Protection of the heart and lungs during implantation is maintained by continuous lavage with cold electrolyte solution, and a line is passed into the appendage of the left atrium for this purpose and to remove air from the left side of the heart. The level of cold irrigant solution is adjusted so that it does not rise excessively and flood the trachea. Both lungs tend to float on the fluid and should be covered with wet laparotomy towels. After completion of the tracheal anastomosis, gentle ventilation is commenced without high oxygen concentrations. The atrial anastomosis is performed next. The incision in the donor right atrium is made in curvilinear fashion, so as to avoid the sinus node (Fig. 3, C). When the left side of the donor right atrium is sutured (Fig. 3,

Heart-lung transplantation 9 3 5

C), the entire septum is included in the suture line, including all remnants of the left atrium. Finally the aortic anastomosis is performed, again with a continuous suture of polypropylene (Fig. 3, D). After all anastomoses have been completed, the chest cavity is emptied of fluid and the caval snares are removed. Air is removed from the heart and the aortic cross-clamp is removed. During resuscitation of the heart, the hole in the left atrial appendage is closed and the pulmonary artery infusion site is sutured. Further maneuvers are performed to remove air from the heart. The patient is ventilated with 40% oxygen and 5 em H 20 of PEEP. Thorough hemostasis is established. Bypass is discontinued after an infusion of isoproterenol is titrated to maintain the heart rate at about 110 beats/min.