Indications for and results of single, bilateral, and heart-lung transplantation for pulmonary hypertension

Cardiac and Pulmonary Replacement

Indications for and results of single, bilateral, and heart-lung transplantation for pulmonary hypertension The indications for single, bilateral, and heart-lung transplantation for patients with pulmonary hypertension remain controversial. We retrospectively analyzed the results from 11 single, 22 bilateral, and 24 heart-lung transplant procedures performed between January 1989 and January 1993 on 57 consecutive patients with pulmonary hypertension caused by primary pulmonary hypertension (n = 27) or Eisenmenger's syndrome (n = 30). Candidates with a left ventricular ejection fraction less than 35 %, coronary artery disease, or Eisenmenger's syndrome caused by surgically irreparable complex congenital heart disease received heart-lung transplantation. All other candidates received single or bilateral lung transplantation according to donor availability. Although postoperative pulmonary artery pressures decreased in all three allograft groups, those in single lung recipients remained significantly higher than those in bilateral and heart-lung recipients. The cardiac index improved significantly in only the bilateral and heart-lung transplant recipients. A significant ventilation/perfusion mismatch occurred in the single lung recipients as compared with bilateral and heart-lung recipients because of preferential blood flow to the allograft. Graft-related mortality was significantly higher and overall functional recovery as assessed by New York Heart Association functional class was significantly lower at 1 year in the single as compared with bilateral and heart-lung recipients. Thus bilateral lung transplantation may be a more satisfactory option for patients with pulmonary hypertension with simple congenital heart disease, absent coronary arterial disease, and preserved left ventricular function. Other candidates will still require heart-lung transplantation. (J THORAC CARDIOVASC SURG 1994;108:1056-65) Ko Bando, MD*a (by invitation), John M. Armitage, MDa (by invitation), Irvin L. Paradis, MD b (by invitation), Robert J. Keenan, MDa (by invitation), Robert L. Hardesty, MD a (by invitation), Hiroaki Konishi, MDa (by invitation), Kanshi Komatsu, MDa (by invitation), Keith L. Stein, MDC (by invitation), Ajit N. Shah, MDd (by invitation), Henry T. Bahnson, MD,a and Bartley P. Griffith, MD,a Pittsburgh, Pa.

From the Divisions of Cardiothoracic Surgery- and Pulmonary Medicine" and the Departments of Critical Care Medicine? and Radiology," University of Pittsburgh School of Medicine, Pittsburgh, Pa. Read at the Seventy-third Annual Meeting of The American Association for Thoracic Surgery, Chicago, Ill., April 25-28, 1993. Address for reprints: Ko Bando, MD, Division of Cardiothoracic Sur-

1056

gery, C-700, Presbyterian University Hospital, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213. *Ko Bando, MD, is the Fortieth Evarts A. Graham Memorial Traveling Fellow of The American Association for Thoracic Surgery. Copyright © 1994 by Mosby-Year Book, Inc. 0022-5223/94 $3.00 + 0

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The choice of lung transplantation procedures to treat patients with end-stage pulmonary vascular disease has evolved since the modern era of lung transplantation began in 1981.' Initially, heart-lung transplantation (HLT) was used to treat all such patients.' This procedure did eliminate the pulmonary hypertension and the right ventricular dysfunction/failure that were due to pulmonary vascular disease. Although histologic changes have occurred in the pulmonary arteries that could lead to recurrent pulmonary hypertension after HLT,3 recurrence of pulmonary hypertension or right ventricular dysfunction has not been observed for as long as 10 years after HLT in our experience. However, during the past 4 years there has been a shift away from HLT toward single (SLT) and bilateral lung transplantation (BLT) to treat patients with end-stage pulmonary hypertension. This trend is the result of the recognition that the function of the right side of the heart would recover if the pressures in the pulmonary circulation were decreased" and the result of the shortage of heart-lung blocks resulting from the increasing popularity and success of heart transplantation. The long-term outcome of patients with pulmonary hypertension treated with SLT and BLT remains unknown.? Although all three transplantation procedures are associated with dramatic decreases in pulmonary arterial pressure, recipients with a SLT would appear to have less vascular and parenchymal reserve. Although early hemodynamic improvement after SLT for pulmonary hypertension has been demonstrated.v'' the longer term consequences of this procedure remain unclear." We compared the hemodynamic and functional outcomes of our SLT, BL T, and HLT recipients who had underlying primary and secondary pulmonary hypertension. Methods Candidate selection. Candidates for SLT, BLT, and HL T were lessthan 60 years old and had limited functional capacity, defined as New York Heart Association (NYHA) functional class III or IV, caused by end-stage primary or secondary pulmonary hypertension. Candidate evaluation included spirometry, arterial blood gases, exercise oxygen titration, quantitative left and right perfusion and ventilation scans, and right heart catheterization with measurement of pulmonary arterial pressures, pulmonary capillary wedge pressure, and cardiac index. Coronary arteriography was performed if candidates were older than 40 years of age. Right and left ventricular ejection fractions were estimated by radionuclide ventriculography. Candidates with a left ventricular ejection fraction less than 35%, significantcoronary artery disease, or complex congenital heart disease were listed for HL T. All other candidates, including those with Eisenmenger's syndrome caused by patent ductus arteriosus, atrial septal defect, or ventricular septal defect, were

10 57

Table I. Characteristics of SLT, BLT, and HLT

recipients with pulmonary hypertension SLT

Gender 4 Male 7 Female Age(yr) 34 ± 12 Mean ± SO 17-57 Range Transplant site Right 7 4 Left Pretransplantation disease 7 PPH Eisenmenger 4 3 ASO I POA 0 VSO Complex CHO 0 Immunosuppression II 9 Cs 2 FK Switch 0 0 Cs -- FK 0 FK -- Cs 0 None* Waiting time(days) 553 ± 282 Mean ± SO

BLT

HLT

6

II

16

13

37 ± 10 14-53

25 ± 13t 1-48

12 10 3 7 0 0 20

8 16 2 0 1 13 20 lOt 10 4 2

17 3

I

I

I

0

I

1 818 ± 471

507 ± 426

SD. standard deviation; PPH. primary pulmonary hypertension; ASD. atrial septal defect; PDA. patent ductus arteriosus; VSD. ventricular septal defect; CHD. congenital heart disease; Cs, cyclosporine: FK. FK 506.

'Recipients who died before starting immunosuppression therapy.

tp < 0.05 versus BLT by Mann-Whitney rank sum test.

listed for either SLTor BLT. N either the severity of the pulmonary hypertension nor the degree of right ventricular dysfunction was considered a contraindication to SL T. The choice of either SLT or BLT was based on donor availability. Recipient population. The population consisted of 57 candidates with primary or secondary pulmonary hypertension who underwent consecutive evaluation and subsequent SLT, BLT, or HLT between January 1989 and January 1993, with followup completed in all recipients up to March 31, 1993 (Table I). No significantdifferences were noted among the three recipient groups in regard to gender, type of pretransplantation disease, and time spent waiting for a transplant. HL T recipients were significantly younger than BLT recipients and fewer received cyclosporine-based immunosuppression. Since January 1989, 10 of 55 (18%) candidates with pulmonary hypertension listed for SLT or BLT and seven of 39 (18%) candidates listed for HL T died before an adequate donor became available (p = NS*). Donor selection and preservation. Lungs were considered acceptable for transplantation if the donor was lessthan 55 years old and had no history of pulmonary disease, no abnormalities on the chest radiograph, adequate gas exchange with an arterial oxygen tension greater than 350 mm Hg on an inspired *NS = Not significant.

The Journal of Thoracic arid Cardiovascular Surgery December 1994

10 5 8 Bando et al.

100

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Fig. 1. A, Actuarial recipient survival. B, Actuarial allograft survival. p eralized Wilcoxon test.

oxygen fraction of 1.0 or an arterial oxygen tension greater than 100 mm Hg on an inspired oxygen fraction of 0.4, and no antibodies to hepatitis B and human immunodeficiency virus; In addition to these criteria, a heart-lung donor was considered acceptable for transplantation if the electrocardiogram and left ventricular function were within normal limits. Recipients were matched with donors by body size and ABO blood group. The techniques for lung and heart-lung procurement have been described.l? The pulmonary preservation solution was Euro-Collins (100 ml/kg per patient) from January 1989 to April 1991 or University of Wisconsin solution (100 nil/kg per patient) from April 1991 to January 1993. 11 Operative technique. SLT was performed as described, with the telescopic technique used for the airway anastomosis.P There were no instances of dehiscence. Unlike SLT in other types' of diseases where cardiopulmonary bypass was seldom necessary, it was used in all candidates with pulmonary hyper-

12

15

< 0.05 SLT versus BLT and HLT by gen-

tension. In seven candidates a right SLTwas performed through a posterolateral thoracotomy, and in four candidates a left SLT was performed through a median sternotomy (see Table I). Candidates with pulmonary hypertension without cardiac defects received either a right or left lung. Three of eight candidates with Eisenmenger's syndrome caused by an atrial septal defect received a right SLT because it permitted cardiac cannulation and closure of the atrial septal defect simultaneously with the lung transplantation. One of eight candidates with Eisenmenger's syndrome caused by a patent ductus arteriosus received a right SLT through a median thoracotomy with simultaneous closure of the patent ductus arteriosus. Two different techniques with cardiopulmonary bypass were used for BL T. The lungs were implanted en bloc as described 13 in the first four recipients; bilateral sequential SLTs through a sternal bithoracotomy (n = 12) or median sternotomy (n = 6)

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CPB

10 5 9

Ischemic Time 400

300

*

200

100

BLT

SLT

o

HLT

SLT

BLT

HLT

Fig. 2. Comparison of the duration of cardiopulmonary bypass (CPB) and ischemic time for SLT, BLT, and HLT. Cardiopulmonary bypass time was significantly (p < 0.01) shorter for SLT than for BLTand HLT by Mann-Whitneyrank sum test. Ischemic time was significantly (p < 0.01) shorter for HLT than for BLT and SLT by MannWhitney rank sum test.

Table II. Left and right ventricular ejection fractions before (pre) and at 4 to 8 weeks after (post) SLT, BLT, and

HLT for pulmonary hypertension SLT

LVEF RVEF

BLT

HLT

Pre

Post

Pre

Post

Pre

Post

57 ± 14

64 ± 12* 44 ± 15*

60 ± II 29 ± 17

69 ± 9* 47 ± 16*

39 ± 15t 29 ± II

65 ± 7* 50 ± 10*

28 ± 10

LVEF, Left ventricular ejection fraction; RVEF, right ventricular ejection fraction . •p < 0.05 versus pretransplantation values by Wilcoxon test. tp < 0.05 versus BLT and SLT before transplantation by Kruskal- Wallis test.

were used in the next 18 candidates.I" 15 Closure of three large calcified patent ductus arteriosis necessitated primary closure of the pulmonary arterial wall and patch closure of the aortic wall under total circulatory arrest and deep hypothermia with an esophageal temperature of 18° C. HLT was performed as described'" through a median sternotomy (n = 21) or bithoracotomy (n = 3). Except for our first candidate, who had primary pulmonary hypertension, all HLT recipients with primary pulmonary hypertension (n = 8) or Eisenmenger's syndrome with simple congenital heart disease (atrial or ventricular septal defect) (n = 3) had left ventricular dysfunction as defined by a left ventricular ejection fraction of less than 35% by radionuclide ventriculography. All other candidates with Eisenmenger's syndrome (n = 13) had surgically uncorrectable complex congenital heart disease (see Table I). One candidate with transposition combined with tricuspid atresia and truncus arteriosus required deep hypothermia because of intraoperative technical difficulties. The HLT procedure in two children with previous Mustard procedures was technically challenging'? because the baffle was calcified and it was difficult to identify the phrenic nerves. One of them required end-to-end inferior and superior vena caval anastomoses. Immediate postoperative care. Differential lung ventilation via a double-lumen endotracheal tube was used for all SLT

recipients. SLT recipients were maintained in a semilateral position with the transplanted side up as much as possible to reduce blood flow to the implanted lung. A bedside perfusion scan was performed within 4 to 6 hours after transplantation to check the patency of the pulmonary anastomoses and to assess the amount of perfusion to each lung. The first ventilation scan was usually performed within 1 week after extubation. The blood flow and ventilation to each lung were calculated as a percentage of total flow and ventilation. Immunosuppression. The postoperative immunosuppression was azathioprine, corticosteroids, and cyclosporine or FK 506, as described'f (see Table I). Immediately before transplantation, azathioprine (4 mg/kg) and methylprednisolone (5 mgjkg) were administered intravenously. Either cyclosporine or FK 506 was begun after the operation by continuous infusion as soon as the recipient was in hemodynamically stable condition. Recipients were switched to oral preparations of these medications after extubation. Statistical analysis. A computer program package (Statsoft Inc., CSS Statistica, Tulsa, Okla.) was used for statistical analysis. Results were expressed as the mean ± standard deviation. Actuarial survival curves (Fig; 1, A and B) were computed by life table analysis and differences were analyzed by the generalized Wilcoxon test.'? Linearized rates (events per 100 patient-

I0 60

The Journal of Thoracic and Cardiovascular Surgery December 1994

Banda et at.

4

--~>--H

3

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* - - SLT - - BLT _ .... HLT

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Fig. 3. A, Change in cardiac index (Cl] before and after SLT, BLT, and HLT. tp < .05 versus pretransplantation values by Wilcoxon test; *p < 0.05 SLT versus BLT and HLT by Mann-Whitney rank sum test. B, Change in mean pulmonary artery pressure (PAP) before and 3 days after SLT, BLT, and HLT. tp < .05 versus pretransplantation values by Wilcoxon test; *p < 0.05 SLT versus BLT and HLT by Mann-Whitney rank sum test. C, Change in pulmonary vascular resistance index (PVRI) before and 3 days after SLT, BLT, and HLT. tp < 0.05 versus prestransplantation by Wilcoxon test. POD, Postoperative day. days) were compared with the maximum likelihood ratio test. 20 Comparisons between SLT, BLT, and HLT recipients for demographics (see Table I), cardiopulmonary bypass and ischemic times (Fig. 2), hemodynamics (Fig. 3, A to C), right and left ventricular ejection fractions (Table 11),ventilation and perfusion (Fig. 4, A to C), and NYHA functional class data (Fig. 5) were made first by the Kruskal-Wallis test and then by the Mann-Whitney rank sum test. 21 Comparisons in the same recipient for these parameters before and after lung transplantation were made by the Wilcoxon signed rank test. 21 The prevalence of postreperfusion adult respiratory distress syndrome/ pulmonary edema and of graft-related death were compared among the three groups by x 2 analysis."

Results Intraoperative. Because SLT necessitated fewer anastomoses, the duration of cardiopulmonary bypass was significantly shorter for SLT than for BLT and HLT recipients (see Fig. 2). Because most HLT donors were

procured locally, the duration of allograft ischemia was significantly shorter than that of BLT and SLT allografts (see Fig. 2). Early postoperative hemodynamics. By the third postoperative day, the cardiac index increased significantly in BLT and HLT recipients but not in SL T recipients, and the postoperative cardiac index in SL T recipients was significantly lower than that in BLT and HLT recipients (see Fig. 3, A). The mean pulmonary arterial pressure decreased significantly in all three allograft groups by 3 days after transplantation, but the mean pulmonary arterial pressure in SLT recipients was still significantly higher than that in BLT and HLT recipients (see Fig. 3, B). These changes in cardiac index and in pulmonary arterial pressure resulted in a significant decrease in the pulmonary vascular resistance index in HLT and BLT but not in SLT recipients (see Fig. 3, C).

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Table III. Causes of mortality and graft loss after SLT, BLT, and HLT for pulmonary hypertension Mortality Graft related

Etiology

A. Mortality/graft loss within 30 days after transplantation SLT

BLT

HLT

2/13 (15%) 2/2 (100%) ARDS/DAD secondary to persistent PH (n = I) ARDS, arrhythmia (n = I) 4/22 (18%) 0/4 (0%) Technical-hemorrhage (n = I) Cerebral ischemia secondary to cardiac arrest (n = I) Bleeding secondary to coagulopathy (n = I) Sepsis syndrome with MSOF (n = I) 4/25 (16%) 1/4 (25%) Bleeding and coagulopathy (n = 1) Technical-oversized donor (n = I) Staphylococcus pneumonia (n = I)

Pseudomonas aeruginosa sepsis secondary to line infection (n= I) B. Mortality/graft loss more than 30 days after transplantation SLT

BLT

HL T

4/13 (30%) 4/4 (100%) Pseudomonas aeruginosa and Staphylococcus pneumonia and sepsis (n = I) OB, Pseudomonas aeruginosa pneumonia (n = I) PTLD (n= I) CMV pneumonia (n = I) 5/22 (23%) 4/5 (800/0) Renal failure and Staphylococcus sepsis (n= I) ARDS + Pseudomonas aeruginosa pneumonia (n = I) ARDS + Staphylococcus aureus pneumonia (n = I) ARDS secondary to Enterobacter pneumonia and sepsis syndrome (n = I) PTLD+OB(n=1) 7/25 (28%) 3/7 (43%) Intraabdominal sepsis secondary to perforated duodenum (n = I) ARDS + OB (n = I) Hemorrhage secondary to TBBx + thrombocytopenia (n = I) Acute cardiac and pulmonary rejection (n = I) PTLD+OB (n= I) Intracerebral hemorrhage + thrombocytopenia (n = 2)

ARDS, Adult respiratory distress syndrome; DAD, diffuse alveolar damage; PH, pulmonary hypertension; MSOF, multisystem organ failure; OB, obliterative bronchiolitis; PTLD, postlransplantation Iymphoproliferative disease; CMV, cytomegalovirus; TBBx, transbronchial biopsy.

Postoperative results. Pulmonary edema developed in the transplanted lung within 24 hours of transplantation in nine of II SLT recipients (82%), whereas this complication developed in only 13 of 22 BLT recipients (59%) and eight of 24 HLT recipients (33%) (p < 0.05 by x2 analysis). In addition, hemodynamic instability with marked but transient increases in pulmonary arterial pressure was common in SLT recipients. These increases in pulmonary arterial pressures frequently resulted in decreases in cardiac output, hypotension, and hypoxemia. As a result, SLT recipients required significantly longer periods of assisted ventilation (399 ± 520 hours) (mean ± standard deviation) than BLT (263 ± 699 hours) and HLT (74 ± 79 hours) recipients (p < 0.05) and longer stays in the intensive care unit (SL T 31 ± 34 days; BLT 16 ± 31 days; HLT 9 ± 9 days; p < 0.05, Mann- Whitney test). Although early mortality among the three groups was similar, both early deaths in the SLT

recipients were graft-related, resulting from adult respiratory distress syndrome ( 100%), whereas only one of the seven early deaths (14%) in the BLT and HLT recipients was graft-related (Table III, A). The other six deaths in the BLT and HLT recipients were due to infection, bleeding, and technical complications. Left ventricular and right ventricular ejection. Left ventricular and right ventricular ejection fraction improved significantly in each allograft group at a mean of 6 weeks after transplantation, and there were no significant differences among the groups (see Table 11). Pretransplantation left ventricular ejection fraction in HLT candidates was significantly lower than that in SLT and BLT candidates. Distribution of ventilation and perfusion. Before transplantation, ventilation (see Fig. 4, A), perfusion (see Fig. 4, B), and the ventilation/perfusion ratio (see Fig. 4, C) were matched in the lung that was ultimately trans-

The Journal of Thoracic and Cardiovascular Surgery December 1994

1 0 6 2 Banda et al.

100

80

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Fig. 4. Ventilation, perfusion, andventilation/ perfusion ratiobeforeand 14 to 22weeks (mean 18 weeks) afterS LT, BLT and HL T. A, Ventilation: Data obtained from allograft for SLT recipients and from right lung for BLT and HLT recipients. B, Perfusion: t p < 0.05 versus pretransplantation values by Wilcoxon test; *p < 0.05 SLT versus BLT and HLT by Mann-Whitneyrank sum test. C, Ventilation/perfusion ratio: t p < 0.05 versus pretransplantation values by Wilcoxon test; *p < 0.05 SLT versus BLT and HLT by Mann-Whitneyrank sum test. planted in all three candidate groups. By a mean of 18 weeks after transplantation, ventilation to the allograft did not change in any group of recipients (see Fig. 4, A). Although perfusion also did not change after BLT and HLT, perfusion to the transplanted lung increasedsignificantly in the SLT recipients (see Fig. 4, B). Because ventilation did not change and perfusion to the allograft increased after SLT, the ventilation/perfusion ratio decreased significantly in the allograft of SLT recipients (see Fig. 4, C). Infection and rejection episodes. Although the duration of intubation was longer in SLT recipients, the number of episodes of infection per 100 patient-days was similar among the three allograft groups (SLT 1.5 episodes; BLT 1.2 episodes; HLT 0.8 episodes) (p = NS by maximum likelihood test). There were also no significant differences in number of rejection episodes per 100 patient-

days among the three allograft groups (SLT 1.4 episodes; BLT 1.3 episodes; HLT 0.9 episodes) (p = NS by maximum likelihood test). Functional and late results. Eight of 11 SLT (73%), 18 of 22 BLT (82%), and 21 of24 HLT recipients (88%) were discharged from the hospital (p = NS by X2 test). Thus survival at 1 and 3 months was similar among the three groups (see Fig. 1, A). One-year survival in SLT recipients was lower than that in BLT and HLT recipients, but this difference did not reach statistical significance (see Fig. I,A). Forty-six percent (6/13) oftheSLT recipients died after transplantation and all of these deaths were graft-related (see Table III, A and B). Forty-one percent ofBLT recipients (9/22) and 44% ofHLT recipients (I 1/25) also died after transplantation, but only 16% of BLT recipients (4/22) and 16% of HLT recipients (4/25) died of graft-related problems (p < 0.05

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Fig. 5. NYHAfunctionalclass beforeand I year after SLT, BLT, and HLT. *p < 0.05SLTversus BLTand HLT by Mann-Whitneyrank sum test. tp < 0.05comparedwith pretransplantation valuesby Wilcoxon signedrank test.

100 ~ o

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Fig. 6. Impact of obliterative bronchiolitis on ventilation and perfusion in the allograft after SLT for pulmonary hypertension. Tx, Transplantation; V, ventilation; Q, perfusion; OB, obliterative bronchiolitis; P02, oxygen tension; Pco-, carbon dioxide tension; Saoi; arterial oxygen saturation.

by x2 analysis). Because of more graft-related deaths in SLT recipients, l-year graft survival was significantly lower in SLT than in BLT and HLT recipients (see Fig. I, B). Deaths more than I month after transplantation (see Table III) in all three allograft groups were primarily due to infection or obliterative bronchiolitis. The prevalence of obliterative bronchiolitis was similar in all three transplant groups. One recipient in each allograft group was lost because of posttransplantation Iymphoproliferative disease. NYHA functional class improved significantly after transplantation in all three transplant groups, but the NYHA functional class of SLT recipients

was still significantly higher than that of BLT and HLT recipients by I year after transplantation (see Fig, 5). Discussion After the first report of a successful SLT for Eisenmenger's syndrome resulting from a patent ductus arteriosus.F several other reports have documented successful SLT for primary and secondary pulmonary hypertension with encouraging early hemodynamic improvement.f 7, 8, 23, 24 However, the results from our 57 SLT, BLT, and HLT recipients with primary and secondary pulmonary hypertension suggest that SLT may be less optimal than BLT and HLT. Although

The Journal of Thoracic and Cardiovascular Surgery December 1994

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SL T did significantly decrease pulmonary arterial pressures (Fig. 3, B), these pressures did not improve as much as those in BLT and HLT recipients. As a result, there was no significant improvement in cardiac index after SLT (see Fig. 3, A) and cardiac function is probably the primary determinant of functional recovery. In addition, SLT recipients experienced more frequent posttransplantation pulmonary edema and more severe hemodynamic instability than BLT and HLT recipients. These complications resulted in insignificantly longer intubation time and intensive care unit stay. Most of the cardiac output flowed through the transplanted lung after SLT (see Fig. 4, B), but the ventilation remained equally divided between the two lungs (see Fig. 4, A). The result was a significant ventilation/perfusion mismatch in the allograft ofSLT (Fig. 4, C) as compared with that in BLT and HLT recipients. This mismatch, however, did not lead to gas exchange abnormalities so long as no infection or rejection was present in the allograft. Nonetheless, these SLT recipients probably have less reserve relative to oxygenation and more readily exhibit hypoxemia and/or respiratory failure for a given level of allograft dysfunction than do BLT and HLT recipients, as illustrated by the example in Fig. 6 and as previously reported." This recipient had normal pretransplantation values for ventilation, perfusion, ventilation/perfusion ratio, and gas exchange. Because of the expected preferential flowof blood through the allograft, the ventilation/perfusion ratio decreased significantly after transplantation, but the gas exchange remained normal. Obliterative bronchiolitis developed 9 months after transplantation, which probably decreased the compliance of the allograft. This increased stiffness of the allograft resulted in a shift of ventilation from the allograft to the normally compliant native lung. The decrease in ventilation to the allograft further increased the ventilation/perfusion mismatch. This increased mismatch now resulted in significant hypoxemia and hypercarbia. The concept that the native lung in the SL T recipient serves a protective "back-up" role may not apply to SLT recipients with pulmonary hypertension, and complications such as infection and acute or chronic rejection may be very poorly tolerated. In our series, all deaths in SL T recipients were graft-related (see Table III) and graft survival after SLTwas significantly poorer than that after BLT and HLT (see Fig. I, B). Although these results raise a flag of caution regarding SL:r in patients with pulmonary hypertension, they must be regarded as preliminary because the number of recipients is small and better long-term measures of functional outcome are needed. Nevertheless, despite early hemo-

dynamic improvement, SLT resulted in less functional recovery and higher graft-related mortality than BLT and HLT. Thus BLT may be a more satisfactory therapeutic option for candidates with pulmonary hypertension and preserved left ventricular function. Candidates with pulmonary hypertension and significant LV dysfunction or Eisenmenger's syndrome caused by complex congenital heart disease still require HLT. REFERENCES 1. Reitz BA, Wallwork JL, Hunt SA, et al. Heart-lung transplantation: successful therapy for patients with pulmonary vascular disease. N Engl J Med 1982;306:55764. 2. Griffith BP, Hardesty RL, Trento A, et al. Heart-lung transplantation: lessons learned and future hopes. Ann Thorac Surg 1987;43:6-16. 3. Yousum SA, Paradis IL, Dauber JH, et al. Pulmonary arteriosclerosis in long term human heart-lung transplant recipients. Transplantation 1987;47:564-9. 4. Pasque MK, Trulock EP, Kaiser LR, Cooper JD. Single lung transplantation for pulmonary hypertension: three month hemodynamic follow up. Circulation 1991;84:22759. 5. Parquin F, Cerrina F, LeRoy Ladurie F, et al. Comparison of hemodynamic outcome of patients with pulmonary hypertension. Transplant Proc 1993;25:1157-8. 6. Maurer JR, Winton TL, Patterson GA, William TR. Single-lung transplantation for pulmonary vascular disease. Transplant Proc 1991;23:1211-2. 7. Levine SM, Gibbons W J, Bryan CL, et al. 'Single lung transplantation for primary pulmonary hypertension. Chest 1990;98:1107-15. 8. Pasque MK, Kaiser LR, Dressler CM, et al. Single lung transplantation for pulmonary hypertension: technical aspects and immediate hemodynamic results. J THORAC CARDIOVASC SURG 1992;103:475-82. 9. Trinkle JK, Smith CR. Discussion of Pasque et al. 8 10. Griffith BP, Bando K, Armitage JM, et al. Lung transplantation at the University of Pittsburgh. In: Terasaki PA, Cecka JM, eds. Clinical transplant 1992. Los Angeles: UCLA Tissue Type Laboratory 1993;149-59. II. Hardesty RL, Aeba R, Armitage JM, Kormos RL, Griffith BP. A clinical trial of University of Wisconsin solution for pulmonary preservation. J THoRAc CARDIOVASC SURG 1993;105:660-6. 12. Calhoon JH, Grover FL, Gibbons WJ, et al. Single lung transplantation: alternative indications and technique. J THORAC CARDIOVASC SURG 1991;101:816-25. 13. Patterson GA, Cooper JD, Goldman B, et al. Technique of successful clinical double-lung transplantation. Ann Thorae Surg 1988;45:626-33. 14. Pasque JH, Cooper JD, Kaiser LR, Haydock DA. Triantafillou A, Trulock EP. Improved technique for bilateral lung transplantation: rationale and initial clinical experience. Ann Thorac Surg 1990;49:785-91. 15. Bisson A, Bonnette P. A new technique for double lung

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16.

17.

18.

19. 20.

21.

22.

23.

24.

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transplantation: bilateral single lung transplantation. J THORAC CARDIOVASC SURG 1992;103:40-6. Reitz BA. Heart and lung transplantation. In: Baumgartner WA, Reitz BA, Achuff SC, eds. Heart and heart-lung transplantation. Philadelphia: WB Saunders, 1990:313-46. Armitage JM, Fricker FJ, Kurland G, et al. Pediatric lung transplantation: the years 1985 to 1992 and the clinical trialofFK 506. J THORAC CARDIOVASCSURG 1993;105:33746. Griffith BP, Bando K, Hardesty RL, et al. Prospective randomized trial of FK 506 versus cyclosporine after human pulmonary transplantation. Transplantation 1994;57:84851. Cox DR. Regression models and life-tables. J R Stat Soc Series B 1972;34:187-220. Gross AJ, Clark VA. Survival distribution: reliability application in the biomedical sciences. New York: John Wiley, 1975:331. Glantz ·SA. How to analyze rates and proportions. In: Glantz SA, ed. Primer of biostatistics. New York: McGraw-Hill, 1981:94-128. Fremes SE, Patterson GA, Williams WG, et al. Single lung transplantation and closure of patent ductus arteriosus for Eisenmenger's syndrome. J THORAC CARDIOVASC SURG 1990;100:1-5. Starnes VA, Lewiston NJ, Luikart H, Theodore J, Stinson EB, Shumway NE. Current trends in lung transplantation: lobar transplantation and expanded use of single lungs. J THORAC CARDIOVASC SURG 1992;104:1060-6. Frist WH, Carmichael LC, Loyd JE, et al. Transplantation for pulmonary hypertension. Transplant Proc 1993; 25:1159-61. Levine SM, Jenkinson SG, Bryan CL, et al. Ventilationperfusion inequalities during graft rejection in patients undergoing single lung transplantation for primary pulmonary hypertension. Chest 1992;101:401-5.

Discussion Dr. G. Alec Patterson (St. Louis, Mo.). Dr. Bando is the fortieth Graham Traveling Fellow and he continues to show all of us his capability for excellent work. The Pittsburgh group has once again introduced a very important issue for discussion. The problem of pulmonary hypertension and how best to treat it by transplantation is unresolved. Our own experience is quite different from the Pittsburgh experience that has just been described. I am not certain why that is. Dr. Bando, you mentioned late perfusion, I think at 18 weeks. Could you tell us whether the early perfusion of those single lung allografts is 90% or 95%, as expected? At Barnes Hospital we have performed SLT in 23 patients having pulmonary hypertension. There have been two operative deaths and two late deaths. Long-term follow-up hemodynamic data are available for 16 patients. Pulmonary artery pressure falls promptly and remains normal. The increase in cardiac output persists,and of course pulmonary vascular resistance is reduced. Dr. Bando, could you explain why your SLT recipients do not have a significant fall in cardiac output?

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We believe that some patients do need HLT (poor left ventricular function, complex congenital cardiac defect). Although BLT may have potential advantages, we believe there are definite disadvantages. Bilateral procedures are technically more difficult. The bypass times in your experience are much longer than in the SLT group. This lends itself to complications, as you have shown. SLT offers a couple of major advantages. Bilateral lung allografts and hearts can be used in different recipients. Our first 19 recipients with primary pulmonary hypertension received single lungs from 18 donors. Those same 18 donors produced II additional single lung allografts and 17 cardiac allografts. Forty-seven thoracic organ transplants from 18 donors is a compelling argument for SLT. The other issue is recipient waiting time. Your waiting time is much longer in BLT recipients than in SLT recipients. We have looked at our own data. We have performed transplantation in 23 of these patients with primary pulmonary hypertension and Eisenmenger's syndrome, who waited an average of 5.2 months. Meanwhile, 12 patients died on our waiting list, having waited only 1.9 months. These are sick patients, and they need the transplant operation to be done promptly. We currently have 13 such patients on our list, and they have already waited 7.7 months. Not only is this a strong argument for SL T, it is also an argument for stratifying patients on waiting lists by disease. My final question is whether you are any more rigorous in your donor selection for SLT than for BLT. We will accept only the very best donors for SLT recipients with pulmonary hypertension. Weare pleased that you brought this controversial subject to the attention of the Association. Dr. Bando. I thank Dr. Patterson for his comments. In response to the first question, cardiac index data 1 or 2 years after transplantation were not available, so we focused on the cardiac index in the immediate postoperative period up to postoperative day 3. The cardiac index immediately after the operation was low because the native lung still had high resistance, and it was not clear that resistance would be reduced a year or two later. With regard to ischemic time and cardiopulmonary bypass time, bypass time was longer for BLT than for SLTor HLT, although the ischemic times were shorter for HLT than for SL T and BLT. Interestingly, however, because most of the pulmonary blood flowgoes to the allograft, SLT recipients had a much higher incidence of posttransplantation reperfusion pulmonary edema/adult respiratory distress syndrome and subsequently had longer intubation times and intensive care unit stays. The question then comes: When a single lung becomes available for a patient with pulmonary hypertension, should SLT be performed? The answer is probably "yes." First, no one knows whether that particular patient will eventually get a bilateral lung donor. Second, we know that some SLT recipients with pulmonary hypertension are doing well. I believe the next focus is to identify factors that determine the outcome of SLT for patients with pulmonary hypertension. Our preliminary results using univariate analysis showed that prolonged cardiopulmonary bypass time, high pulmonary arterial pressure immediately after transplantation, and infections are significant risk factors in our 13 patients with pulmonary hypertension who underwent SLT.