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Address reprint requests to Hiroshi Date, Department of Thoracic Surgery, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
In standard bilateral living-donor lobar lung transplantation (LDLLT), right and left lower lobes donated by 2 healthy donors are implanted into a recipient after right and left pneumonectomies. Because only 2 lobes are implanted, the grafts may be too small for an adult recipient. To overcome size mismatch, we have developed a technique of right-to-left inverted LDLLT based upon the fact that the right lower lobe is generally larger than the left lower lobe. In right-to-left inverted LDLLT, 2 donors donate their right lower lobes. The right graft is implanted in the right side of the recipient. The left graft is inverted and implanted in the left side. This operation is indicated when total graft forced vital capacity (FVC) is less than 60% of the recipient's predicted FVC or when donor's left lower lobectomy is technically difficult due to interlobar pulmonary artery anatomy.
To overcome size mismatch in living-donor lobar lung transplantation (LDLLT), we have developed a technique of right-to-left inverted LDLLT.
Living-donor lobar lung transplantation (LDLLT) is a valuable option for patients who would not survive the long waiting period in the area of severe brain-dead donor shortage.
In standard LDLLT, right and left lower lobes donated by 2 healthy donors are implanted into a recipient after right and left pneumonectomies under cardiopulmonary support.
For “functional size matching,” we have made a formula for estimating the graft forced vital capacity (FVC) based on the donor's measured FVC and the number of pulmonary segments implanted.
Our acceptable lower threshold of the total FVC of the 2 grafts is 45% of the predicted FVC of the recipient (calculated based on height, age, and sex). Because only 2 lobes are implanted, the grafts may be too small for an adult recipient resulting in pulmonary hypertension and lung edema. To overcome this problem, we have developed a technique of right-to-left inverted LDLLT (Fig. 1)
It was developed based upon the fact that the right lower lobe (5 segments) is generally larger than the left lower lobe (4 segments). We previously reported that the FVC of inverted RLL was about 270 ml more than that of LLL at 6 months after transplantation.
Right-to-left inverted LDLLT is indicated when estimated graft forced vital capacity (FVC) is less than 60% of the recipient's predicted FVC or when donor's left lower lobectomy would be technically difficult due to interlobar pulmonary artery anatomy.
Figure. 1Right-to-left bilateral living-donor lobar lung transplantation. Two donors donate their right lower lobes. The right graft is implanted in the right side. The left graft is inverted and implanted in the left side. RLL, right lower lobe.
In this procedure, donor left lung was divided into the left upper lobe graft and the left lower lobe graft. The left upper lobe graft was inverted and implanted into the right chest cavity of the recipient. Then, the left lower graft was implanted into the left chest cavity. In 2001, the same group reported successful right single lung transplantation using donor left lung graft for a patient with prior history of left pneumonectomy.
Implanting a contralateral lung graft is technically challenging. When a contralateral donor lung graft is placed in the recipient chest cavity after a 180° rotation around its superior-inferior axis from its anatomic position, the anatomic posterior aspect of the donor lung becomes anterior in the recipient chest. As a result, the pulmonary arteries of the donor and the recipient are on opposite sides of the bronchus. Therefore, how to avoid vascular kinking is a critical issue in performing contralateral donor lung implantation.
In this manuscript, technical details of right-to-left inverted LDLLT are presented.
Donor Right Lower Lobectomy
The procedure involves 2 right lower lobectomies from 2 healthy relatives. Three-dimensional multidetector computed tomography angiography is created for the confirmation of the pulmonary arterial and venous anatomy. The completeness of pulmonary fissures is carefully evaluated by high-resolution computed tomography.
Epidural catheters for postoperative analgesia are placed routinely the day before the surgery to avoid complications related to heparinization during the donor lobectomies. After induction of general anesthesia, donors are intubated with a left-sided double lumen endotracheal tube. Fiberoptic bronchoscopy is performed to determine if lower lobectomy is feasible leaving adequate length for closure on the donor bronchus and length for anastomosis in the recipient.
The donors are placed in the lateral decubitus position and a posterolateral thoracotomy is performed though the fifth intercostal space. Fissures are developed using linear stapling devices. Dissection in the fissure is carried out to isolate the pulmonary artery to the lower lobe, and to define the anatomy of the pulmonary arteries to the middle lobe. The pericardium surrounding the inferior pulmonary vein is opened circumferentially so that a vascular clamp can be placed deep enough.
Two thousand units of heparin and 125 mg of methylprednisolone are administered intravenously. After placing vascular clamps in appropriate positions, the division of the pulmonary vein, the pulmonary artery and bronchus are carried out in this order.
For the division of lower pulmonary vein (Fig. 2), two 5-0 Prolene corner stitches are placed peripherally to the clamp before division. In the event of slippage of the left atrial clamp, the stitches can be pulled up and the left atrium can be re-clamped.
Figure 2Dissection and division of the right inferior pulmonary vein for donor right lower lobectomy. The pericardium surrounding the inferior pulmonary vein is opened circumferentially. A vascular clamp is placed on the intrapericardial left atrium. Two 5-0 Prolene corner stitches can be placed peripherally to the clamp before division. In the event of slippage of the left atrial clamp, the stitches can be pulled up and the left atrium can be reclamped. RML, right middle lobe; RLL, right lower lobe.
Then the interlobar pulmonary artery is divided in an oblique fashion (Fig. 3). If the branches of middle lobe artery are small, they are ligated and divided. However, if such branches are large enough, arterioplasty using autopericardial patch should be performed.
Figure. 3Division of the right interlobar pulmonary artery for donor right lower lobectomy. Dissection in the fissure is carried out to isolate the pulmonary artery to the lower lobe, and to define the anatomy of the pulmonary arteries to the middle lobe. The distance between the superior segmental artery to the middle lobe artery is variable. After placing a vascular clamp, the interlobar pulmonary artery is divided in an oblique fashion. RUL, right upper lobe; RML, right middle lobe; RLL, right lower lobe.
Finally, the lower bronchus is divided (Fig. 4). A 25-gauge needle is inserted through the bronchus at the level of planned division line. Simultaneous bronchoscopy is conducted for internal examination. The right lower bronchus is divided along an oblique line above the segmental bronchus to the superior segment inferiorly to just below the take-off the middle lobe bronchus.
Figure. 4Division of the right lower bronchus. A 25-gauge needle is inserted through the bronchus at the level of planned division line. Simultaneous bronchoscopy is conducted for internal examination. The right lower bronchus is divided along an oblique line above the segmental bronchus to the superior segment inferiorly to just below the take-off the middle lobe bronchus. PA, pulmonary artery.
Vascular stumps are closed with 5-0 polypropylene running sutures. The bronchus is closed with 4-0 polypropylene interrupted sutures. The bronchial stump is covered with pedicled pericardial fat tissue.
On the back table, the lobes are flushed with cold preservation solution in antegrade and retrograde fashion from a bag about 50 cm above the table. Lobes are gently ventilated with room air during the flush. The larger donor lobe is usually used as the right graft and the smaller one as the left graft.
Recipient Implantation
The recipient is anesthetized and intubated with a left-sided double lumen endotracheal tube. A Swan-Ganz catheter is placed via the right intrajugular vein. With the supine position, the “clamshell” incision is used and both chest cavities are entered through the 4th intercostal space. The sternum is notched at the level of transection by aiming the sternal saw at a 45 degrees angle and cutting toward the midpoint to facilitate postoperative sternal coaptation. Pleural and hilar dissections are performed as much as possible before heparinization. Then the pericardium is opened for subsequent cardiopulmonary support. We use extracorporeal membrane oxygenation (ECMO) instead of conventional cardiopulmonary bypass. Activated clotting time is maintained between 180 to 200 seconds to decrease blood loss. The ascending aorta is cannulated for blood supply. Two cannulas are used for blood removal. One drainage cannula is inserted to the right atrium via the right femoral vein. The other cannula is inserted to the superior vena cava via the right appendage.
Right Graft Implantation
The right-side ventilation is stopped while maintaining left-side ventilation. ECMO flow is controlled at 50-70% of total cardiac output and mean systemic pressure is maintained at 50-80 mmHg.
Right pneumonectomy is performed using staplers. Meticulous hemostasis in the posterior mediastinum is achieved at this point. The pericardium is opened circumferentially around the left atrium. Interatrial groove is developed to permit proximal placement of a vascular clamp. The right pulmonary artery is separated from the surrounding tissue behind the superior vena cava. The chest is irrigated with warm saline and 60 mg of Tobramycin is administered into the chest cavity hoping for preventing pleural infection.
The right main bronchus is transected just proximal to the upper bronchial take-off. We preserve peribronchial tissue around the recipient right mainstem bronchus to avoid ischemic change. A moist cold sponge is placed in the right chest cavity and the right lower lobe of the donor rests on this during implantation. The bronchial anastomosis is begun with a running 4-0 polydioxanone suture for membranous portion (Fig. 5). The cartilaginous rings of the donor and recipient are jointed with simple interrupted 4-0 polydioxanone sutures (Fig. 6). No attempt is made to intentionally intussuscept of the donor lower bronchus to the recipient main bronchus. The bronchial wrapping is not employed.
Figure. 5Bronchial anastomosis in the right lower lobe implantation. The bronchial anastomosis is begun with a running 4-0 polydioxanone suture for membranous portion and completed with simple interrupted sutures for cartilaginous portion. RMSB, right mainstem bronchus; RPA, right pulmonary artery; RPV, right pulmonary vein; RLL, right lower lobe.
Figure. 6Pulmonary venous anastomosis in the right lower lobe implantation. The venous anastomosis is conducted between the donor inferior pulmonary vein and the recipient superior pulmonary vein using a running 6-0 polypropylene suture. RPV, right pulmonary vein.
The right pulmonary venous anastomosis is performed by connecting the donor lower pulmonary vein to the recipient upper pulmonary vein. A vascular clamp is place on the recipient’ left atrium intrapericardially. The back wall of the venous anastomosis is performed with running 6-0 Prolene suture (Fig. 6). It is important to assure intima-to-intima approximation. The anterior wall of the venous anastomosis is performed in the same fashion and the sutures are kept untied.
A vascular clamp is placed on the right main pulmonary artery behind the superior vena cava from the caudal side. The right pulmonary artery is transected proximal to the first branch. Leaving long pulmonary artery may increase the risk of arterial kinking after reperfusion. The pulmonary artery anastomosis is performed with running 6-0 Prolene suture as same as for pulmonary vein anastomosis (Fig. 7). At completion of the anastomosis, heparinized saline solution is injected into the pulmonary artery to remove residual air.
Figure 7Pulmonary arterial anastomosis in the right lower lobe implantation. The pulmonary arterial anastomosis is completed in an end-to-end fashion using a running 6-0 polypropylene suture.
The right graft is reperfused by loosening the pulmonary artery clamp momentarily while the graft is re-ventilated gradually. The anterior wall of the venous anastomosis is kept open to allow de-airing of the right graft with the atrial clamp still in place. The venous sutures are then secured and the clamps are removed.
Left Graft (Inverted Right Lower Lobe) Implantation
The heart is gently lifted to expose the posterior pericardium and a pericardial stich is placed near the left lower pulmonary vein. The stitch with the episiotomy pack is snared down using a red rubber catheter to the posterior pericardium. Using the fixed episiotomy pack, the heart is lifted toward the right shoulder of the patient. This maneuver provides excellent exposure of the left hilum (Fig. 8).
Figure 8Retraction of the heart to expose left hilum. Using the fixed episiotomy pack, the heart is lifted toward the right shoulder of the patient. This maneuver provides excellent exposure of the left hilum. RLL, right lower lobe.
The left lung ventilation is stopped while the implanted right graft is kept ventilated. Systolic pulmonary arterial pressure is kept over 20 mmHg by controlling ECMO flow to ensure adequate blood flow to the first implanted right graft.
Left pneumonectomy is performed in a different way to make subsequent inverted graft implantation easier (Fig. 9). The left pulmonary artery is kept long by dividing several pulmonary artery branches to the left upper lobe. The left upper bronchus and lower bronchus are divided separately by staplers. The lower bronchial stump is reinforced by several 4-0 Prolene stitches and left. In our experience, leaving recipient's bronchial stump has never resulted in bronchial fistula.
Figure 9Left pneumonectomy. The left pulmonary artery is kept long by dividing several pulmonary artery branches to the left upper lobe. The left upper bronchus and lower bronchus are divided separately by staplers. The lower bronchial stump is reinforced by several 4-0 Prolene stitches and left. LPA, left pulmonary vein; PV, pulmonary vein; Ao, Aorta.
Considering that the bronchus is a rigid structure that mainly determines the position of the implanted lung graft, we prefer to anastomose the bronchus first. The left upper bronchus is opened by excising the stapler line of the stump. After rotating the right lower lobe graft from its anatomic position to 180° around its superior-inferior axis, the inverted graft is placed in the recipient's left chest cavity. Therefore, the posterior border of the inverted graft becomes anterior and its anterior border lies posteriorly along the spine. As a result, the membranous portion of the donor lower bronchus is positioned opposite the cartilaginous portion of the recipient upper bronchus and vice versa. The bronchial anastomosis is begun with a running 4-0 polydioxanone suture for the posterior part (Fig. 10). The bronchial anastomosis is competed with simple interrupted 4-0 polydioxanone sutures for the anterior part (Fig. 11).
Figure. 10Bronchial anastomosis in the inverted right lower lobe implantation. The membranous portion of the donor lower bronchus is positioned opposite the cartilaginous portion of the recipient upper bronchus and vice versa. The bronchial anastomosis is begun with a running 4-0 polydioxanone suture for the posterior part. The bronchial anastomosis is competed with simple interrupted 4-0 polydioxanone sutures for the anterior part. RLL, right lower lobe.
Figure 11Pulmonary artery anastomosis behind the bronchus. The graft is retracted medially to expose the posterior aspect. This maneuver allows the surgeon to perform pulmonary artery anastomosis behind the bronchus. The back wall of the left pulmonary artery is anastomosed using a running suture of 6-0 Prolene.
Then the graft is retracted medially to expose the posterior aspect. This maneuver allows the surgeon to perform pulmonary artery anastomosis behind the bronchus. A Satinsky vascular clamp is placed proximally on the recipient left main pulmonary artery from the cranial side. The recipient's left pulmonary artery is transected at the appropriate level, which usually results in leaving 1-2 stamps of the pulmonary artery branch. To avoid twisting vascular anastomosis, 2 corner stiches are placed at first. Then, the back wall of the left pulmonary artery is anastomosed using a running suture of 6-0 Prolene (Fig. 11). The retraction of the graft is released and the graft is placed naturally in the left chest cavity. The anterior wall anastomosis of the pulmonary artery is completed with a 6-0 Prolene running suture (Fig. 12). Prior to completing the anastomosis, the pulmonary artery is flushed with heparinized saline to eliminate air in the artery. Occasionally, the left PA anastomosis could be done from an anterior approach when donor graft PA was relatively long.
Figure 12Anterior wall of pulmonary artery anastomosis. The graft is placed naturally in the left chest cavity. The anterior wall anastomosis of the pulmonary artery is completed with a 6-0 Prolene running suture. LPA, left pulmonary artery; PV, pulmonary vein.
The last anastomosis is pulmonary vein. The lower pulmonary vein of the inverted graft is connected to the recipient upper pulmonary vein. Occasionally, the recipient’ left atrial appendage can be used for anastomosis. A vascular clamp is placed on the left atrium from the caudal side intrapericardially. The back wall of the venous anastomosis is performed with a running 6-0 Prolene suture followed by the anterior wall anastomosis in the same fashion (Fig. 13). The inverted graft is reperfused and reventilated in the same manner as for the right side.
Figure 13Pulmonary venous anastomosis in the inverted right lower lobe implantation. The lower pulmonary vein of the inverted graft is connected to the recipient upper pulmonary vein. The back wall of the venous anastomosis is performed with a running 6-0 Prolene suture followed by the anterior wall anastomosis.
ECMO is gradually weaned off while pulmonary arterial pressure is carefully monitored. Heparin is revered by protamine and 2 chest tubes are placed in each chest cavity. Three wires are placed on the sternum and the chest is closed.
Closing
Between 2014 and 2019, we performed right-to-left inverted living-donor lobar lung transplantation in 15 patients (
). None of the patients developed vascular or bronchial complications related to the inversion technique. The 3-year survival rate was 92.3%. All the donors returned to their regular routine postoperatively. Right-to-left inverted LDLLT is a safe and useful option with encouraging intermediate outcome.