Pulmonary retransplantation for obliterative bronchiolitis:

One year survival worse for lung retransplants relative to primary lung transplants

BACKGROUND

Outcomes after lung re-transplantation (LRT) remain inferior compared to primary lung transplantation (PLT). We examined the impact of center volume on one-year survival after LRT.

METHODS

Using the UNOS database, we abstracted patients undergoing PLT and LRT between January 2006 and December 2017, excluding combined heart-lung transplants and multiple re-transplants. One-year survival after PLT and LRT were compared using propensity score matching. In the LRT cohort, multivariable Cox models with and without time-dependent coefficients were fitted to examine association between transplant center volume and 1-year survival. Center volume was categorized based on inspection of restricted cubic splines.

RESULTS

A total of 20,675 recipients (PLT 19853 [96.0%] vs. LRT 822 [4.0%]) were included. One-year survival was lower for LRT recipients in the matched cohort (PLT 84.8% vs LRT 76.7%). There was steady improvement in one-year survival after LRT (2006-2009 72.1% vs. 2010-2013 76.6% vs. 2014-2017 80.1%). Higher center volume was associated with better 1-year survival after LRT. This survival difference was noted in the initial 30 days after transplantation (Intermediate vs. Low volume, HR 0.282 [0.151-0.526]; High vs. Low volume HR 0.406 [0.224-0.737]) but became insignificant after 30 days.

CONCLUSIONS

Superior 1-year survival after LRT at higher volume centers is predominantly due to better 30-day outcomes. This finding suggests that LRT candidates may be referred to higher volume centers for surgery.

The Optimal Procedure for Retransplantation After Single Lung Transplantation

BACKGROUND

Retransplantation has emerged as a therapeutic option for patients experiencing respiratory failure after single lung transplantation. However, outcomes associated with the surgical option (ipsilateral, contralateral, or bilateral lung retransplantation) has not been well evaluated.

METHODS

The Organ Procurement and Transplantation Network database (1994 to 2012) was queried for all lung transplant procedures performed after an initial single lung transplantation. Donor and recipient demographics, before and after transplant characteristics, and outcomes were stratified by retransplant procedural choice and by interval between transplants. Risk factors for mortality were evaluated by Cox proportional hazards regression analysis.

RESULTS

Of 325 prior single lung transplant recipients, 50 underwent ipsilateral, 175 contralateral, and 100 bilateral lung retransplantation. The number of retransplant procedures performed per year increased from 3 in 1994 to 31 in 2012, with an increasing proportion of contralateral retransplantation and declining proportions of ipsilateral and bilateral retransplantation. Survival was significantly better in the contralateral and bilateral retransplant groups than in the ipsilateral retransplant group at 30 days (94% and 89% versus 80%), 1 year (72% and 67% versus 50%), and 5 years (41% and 42% versus 20%). Ipsilateral retransplantation (hazard ratio 1.48; p = 0.042), mechanical ventilation before retransplant (hazard ratio 2.39; p < 0.001), and retransplantation performed in the first half of the study period (hazard ratio 1.45; p = 0.027) were associated with increased mortality.

CONCLUSIONS

After an initial single lung transplant, both the incidence of retransplantation and postoperative survival have increased with time. Although ipsilateral lung retransplantation may be the best available alternative in particular circumstances, this analysis suggests that contralateral or bilateral lung retransplantation may be preferable in patients for whom those options are medically sensible.

Survival After Lung Retransplantation in the United States in the Current Era (2004 to 2013): Better or Worse?

BACKGROUND

To understand the current patient survival after lung retransplantation (LRTx) in the United States, which has historically been worse compared with primary lung transplantation (LPTx).

METHODS

The United Network for Organ Sharing (UNOS) registry was retrospectively analyzed to determine survival after adult LRTx performed in 604 (2.48%) of 14,850 patients from 2004 to 2013. After exclusions, 582 LRTx and 13,673 LPTx recipients were selected for analysis. Cox proportional hazards regression models were used to determine the prognosticators of survival after LRTx. Survival after LRTx and LPTx were compared using Kaplan-Meier analysis.

RESULTS

The median survival after LRTx was 2.6 years compared with 5.6 years after LPTx. One-year, 3-year, and 5-year survival rates were, respectively, 71.1%, 46.3%, and 34.5% for LRTx, and 84.3%, 66.5%, and 53.3% for LPTx (p < 0.001). On multivariate analysis, patients who had LRTx after a greater than 1-year interval survived longer (relative risk [RR] 0.53; 95% confidence interval [CI] 0.34% to 0.88%; p = 0.008). Lower survival was associated with single-lung transplantations (RR 1.49; 95% CI, 1.06% to 2.07%; p = 0.021), transplantations done between 2009 and 2013 (RR 1.40; CI, 1.01% to 1.94%; p = 0.041), multiple (>1) retransplantations (RR 2.55; 95% CI, 1.14% to 5.72%; p = 0.023), and recipients requiring pre-transplantation ventilator support. The only significant donor variable for poor survival was death due to cerebrovascular accidents (RR 1.98; 95% CI, 1.23% to 3.18%; p = 0.004).

CONCLUSIONS

Patient survival after LRTx in the United States has improved compared with historical data but remains lower than LPTx. Careful recipient selection and preoperative optimization based on the factors identified in our study may help utilize resources better and improve survival after LRTx. Bilateral LRTx should be preferentially performed as much as possible. Poor candidates for LRTx include those requiring retransplantations more than once or within 1 year. Prospective multi-institutional studies are necessary to help better understand the actual role of these factors in LRTx.

Lung retransplantation

Lung retransplantation comprises a small proportion of lung transplants performed throughout the world, but has become more frequent in recent years. The selection criteria for lung retransplantation are similar to those for initial lung transplant. Survival after lung retransplantation has improved over time, but still lags behind that of initial lung transplantation. These differences in outcome may be attributable to medical comorbidities. Lung retransplantation appears to be ethically justified; however, the optimal approach to lung allocation for retransplantation needs to be defined.

Outcomes after Lung Retransplantation in the Modern Era

RATIONALE

Characteristics of and survival estimates for recipients of lung retransplantation in the modern era are unknown.

OBJECTIVES

To compare lung retransplant patients in the modern era with historical retransplant patients, to compare retransplant patients with initial transplant patients in the modern era, and to determine the predictors of the risk of death after lung retransplantation.

METHODS

We performed a retrospective cohort study of patients who underwent lung retransplantation between January 2001 and May 2006 in the United States (modern retransplant cohort). The characteristics and survival of this cohort were compared with those of patients who underwent first lung retransplantation between January 1990 and December 2000 (historical retransplant cohort) and patients who underwent initial lung transplantation between January 2001 and May 2006 (modern initial transplant cohort).

MEASUREMENTS AND MAIN RESULTS

Modern retransplant recipients (n = 205) had a lower risk of death compared with that of the historical retransplant cohort (n = 184) (hazard ratio, 0.7; 95% confidence interval, 0.5-0.9; P = 0.006). However, modern retransplant recipients had a higher risk of death than that of patients who underwent initial lung transplantation (n = 5,657) (hazard ratio, 1.3; 95% confidence interval, 1.2-1.5; P = 0.001), which appeared to be explained by a higher prevalence of certain comorbidities. Retransplantation at less than 30 days after the initial transplant procedure was associated with worse survival.

CONCLUSIONS

Outcomes after lung retransplantation have improved; however, retransplantation continues to pose an increased risk of death compared with the initial transplant procedure. Retransplantation early after the initial transplant poses a particularly high mortality risk.

Obliterative Bronchiolitis

Obliterative bronchiolitis (OB) is a condition characterized by inflammation and fibrosis of the bronchiolar walls resulting in narrowing or obliteration of the bronchiolar lumen. The most common causes are childhood lower respiratory tract infection, hematopoietic stem cell or lung and heart-lung transplantation, and toxic fume inhalation. The most frequent clinical manifestations are progressive dyspnea and dry cough. Pulmonary function tests demonstrate airflow obstruction and air trapping. Radiographic manifestations include reduction of the peripheral vascular markings, increased lung lucency, and overinflation. The chest radiograph, however, is often normal. High-resolution CT is currently the imaging modality of choice in the assessment of patients with suspected or proven OB. The characteristic findings on high-resolution CT consist of areas of decreased attenuation and vascularity (mosaic perfusion pattern) on inspiratory scans and air trapping on expiratory scans. Other CT findings of OB include bronchiectasis and bronchiolectasis, bronchial wall thickening, small centrilobular nodules, and three-in-bud opacities. Recent studies suggest that hyperpolarized ³He-enhanced magnetic resonance imaging may allow earlier recognition of obstructive airway disease and therefore may be useful in the diagnosis and follow-up of patients with OB.

Lung retransplantation for bronchiolitis obliterans syndrome: long-term follow-up in a series of 15 recipients

BACKGROUND

Although lung retransplantation is the only definitive therapeutic option in lung recipients with bronchiolitis obliterans syndrome (BOS), its value remains a considerable source of controversy. We report our experience of retransplantation for BOS performed in our center since 1988.

METHODS

Between 1988 and 2002, 15 lung retransplantations for BOS were performed. Patient survival, causes of death, long-term functional status, and BOS recurrence rate were reviewed.

RESULTS

The retransplantation procedure was single-lung transplantation (SLT) in all cases (ipsilateral SLT, n = 4; contralateral SLT, n = 9; SLT after previous double-lung transplantation, n = 2). The median time between primary lung transplantation and retransplantation was 31 months (range, 12 to 39 months). The median follow-up duration of the 10 patients surviving beyond 6 months was 49.5 months (range, 16.5 to 105 months), and 5 patients were followed up for > 5 years. Actuarial survival rates at 1 year, 2 years, and 5 years after retransplantation were 60%, 53%, and 45%, respectively. Ten patients died during long-term follow-up, 6 of them from infection (60%). The retained graft was the initial site of the fatal infection in four of these six patients (66%). Two other patients with a retained graft experienced disabling chronic purulent expectoration arising from the old graft. In the 10 patients surviving beyond 6 months, mean best FEV(1) was 58 +/- 13% of predicted (+/- SD), and actuarial freedom from BOS (stage 1, 2, or 3) at 1 year, 3 years, and 5 years was 90%, 72%, and 66%, respectively.

CONCLUSION

Lung retransplantation offered a viable therapeutic option for selected lung recipients with BOS. Given the morbidity and mortality related to the retained graft, we now favor replacement of the primary graft when retransplantation is considered.

Experience with lung transplantation

BACKGROUND

On the basis of a 5-year experience with heart transplantation and long-term animal experimentation, a lung transplantation program was instituted in 1987. After 10 years of experience, the entire patient population was reviewed.

METHODS

Hospital records were reviewed to evaluate the underlying diagnosis, year of transplantation, type of procedure, and long-term follow-up. The changing scope of indications, procedures performed, and donor criteria, as well as survival data for various subgroups of high-risk candidates, were also examined.

RESULTS

A total of 283 heart-lung (n = 46), single-lung (n = 94), and bilateral lung transplantation procedures (n = 143) were performed, with 22 patients undergoing 24 retransplantation procedures. The overall 5-year survival rate was 63%, with no difference between types of operations. Patients with cystic fibrosis, emphysema, pulmonary fibrosis, and secondary pulmonary hypertension showed similar survival rates; primary pulmonary hypertension was associated with a lower long-term survival. In all groups, the bronchiolitis obliterans syndrome occurred at a rate of approximately 15%/year.

CONCLUSIONS

Acceptable long-term results can be obtained with lung transplantation. Because of expanded indications, no survival benefit was gained in the overall population over a 10-year period. The major obstacle to true long-term survival remains the bronchiolitis obliterans syndrome.

Salvage by volume reduction of chronic allograft rejection in emphysema

BACKGROUND

We hypothesized that native lung volume reduction surgery (LVRS) would improve respiratory function in patients who had previously undergone single lung transplantation for emphysema and who were disabled by obliterative bronchiolitis.

METHODS

Seven single lung transplant recipients who had advanced bronchiolitis obliterans syndrome (BOS grade 3b), absence of active infection, and suitable anatomy underwent native LVRS. Mean time from lung transplantation to LVRS was 39 +/- 17 months.

RESULTS

Mean FEV1 rose from 684 +/- 164 ml before LVRS to 949 +/- 219 ml at 3 months after LVRS, an increment of 40% (p = .002). Mean 6-minute walk rose from 781 +/- 526 ft before LVRS to 887 +/- 539 ft at 3 months after LVRS (p = .031), and mean dyspnea index declined from 3.1 +/- 1.1 before LVRS to 1.6 +/- 0.5 at 3 months after LVRS (p = .010). Mean native lung volume declined from 2956 +/- 648 ml before LVRS to 2541 +/- 621 ml at 3 months after LVRS, but the change was not statistically significant (p = .12). Mean transplant lung volume was little changed before and after LVRS (2099 +/- 411 ml and 1931 +/- 607 ml, respectively, p = NS). There was also a trend toward increased ventilation and perfusion of the native lung and reduction in ventilation and perfusion of the transplant lung, but these changes did not achieve statistical significance. By six months after LVRS, three patients died (two as a consequence respiratory failure), and survivors began to show evidence of deteriorating spirometry.

CONCLUSIONS

LVRS is capable of salvaging respiratory function in chronic allograft rejection in emphysema by reducing native lung hyperinflation. These benefits, however, appear to be limited in magnitude and duration by the severity of the underlying allograft dysfunction.

Pulmonary retransplantation

BACKGROUND AND METHODS

Despite improving results in lung transplantation, a significant number of grafts fail early or late postoperatively. The Pulmonary Retransplant Registry was founded in 1991 to determine the predictors of outcome after retransplantation, so as to facilitate decisions concerning the appropriateness of lung retransplantation in individual patients. In this study, 230 patients underwent retransplantation in 47 centers from 1985 to 1996. Logistic regression methods were used to determine variables associated with, and predictive of, survival and lung function after retransplantation.

RESULTS

Actuarial survival was 47%+/-3%, 40%+/-3% and 33%+/-4% at 1, 2, and 3 years, respectively. On multivariable analysis, the predictors of survival included ambulatory status or lack of ventilator support preoperatively (P=.005, odds ratio 1.62, 95% confidence interval 1.15-2.27), followed by retransplantation after 1991 (P=.048, odds ratio 1.41, 95% confidence interval 1.003-1.99). Ambulatory, nonventilated patients undergoing retransplantation after 1991 had a 1-year survival rate of 64%+/-5% versus 33%+/-4% for nonambulatory, ventilated recipients. Eighty-one percent, 70%, 62%, and 56% of survivors were free of bronchiolitis obliterans syndrome at 1, 2, 3, and 4 years after retransplantation, respectively. Factors associated with freedom from stage 3 (severe) bronchiolitis obliterans syndrome at 2 years after retransplantation included an interval between transplants greater than 2 years (P=.01), the lack of ventilatory support before retransplantation (P=.03), increasing retransplant experience within each center (5th and higher retransplant patient, P=.04) and total center volume of 5 or more retransplant operations (P=.05).

CONCLUSIONS

Nonambulatory, ventilated patients should not be considered for retransplantation with the same priority as other candidates. The best intermediate-term functional results occurred in more experienced centers, in nonventilated patients and in patients undergoing retransplantation more than 2 years after their first transplantation. In view of the scarcity of lung donors, patient selection for retransplantation should remain strict.

Lung retransplantation in children

BACKGROUND

Early primary graft failure due to reperfusion injury may occur in up to 10% of all patients undergoing lung transplantation. Late graft failure in the form of bronchiolitis obliterans progressively increases in frequency as posttransplantation follow-up increases. In both situations, the degree of pulmonary dysfunction may worsen and result in the death of the recipient. The only treatment in many instances is retransplantation. The results in adults are reasonably well established.

METHODS

We reviewed our experience in children. Of the 136 transplant procedures performed to date in children, 14 have been retransplantations. Six patients required retransplantation for early primary graft failure and 8 underwent retransplantation for bronchiolitis obliterans.

RESULTS

There were three early and three late deaths. The actuarial survival at 2 years is 58%. The retransplant procedures were more complex than the primary transplant operations as evidenced by the longer time on cardiopulmonary bypass (199 +/- 71 versus 150 +/- 41 minutes; p < 0.01) and the greater volume of blood transfused (1,303 +/- 936 versus 570 +/- 300 mL; p < 0.01). Two of the long-term survivors who received transplants for bronchiolitis obliterans have subsequently had development of this same condition and 1 died secondary to this. In four instances living related donors were used for the retransplant procedure. The most striking difference in these procedures compared with those transplantations performed with cadaveric donors was the shorter donor lung ischemic times (99.5 and 123.3 minutes for the two lungs for living related donors and 251 and 293 minutes for the first and second lung for the cadaveric donors; p < 0.01).

CONCLUSIONS

We believe that lung retransplantation in children is a reasonable therapy to offer in the circumstance of severe graft dysfunction. In the older child, the option of living donor transplantation offers advantages that might offset of the overall higher risk of this procedure.

Pulmonary retransplantation: predictors of graft function and survival in 230 patients. Pulmonary Retransplant Registry

BACKGROUND

Despite improving results in lung transplantation, a significant number of grafts fail early or late postoperatively. The pulmonary retransplant registry was founded in 1991 to determine the predictors of outcome after retransplantation. We hypothesized that ambulatory status of the recipient and center retransplant volume, which had been previously shown to predict survival after retransplantation, would also be associated with improved graft function postoperatively.

METHODS

Two hundred thirty patients underwent retransplantation in 47 centers from 1985 to 1996. Logistic regression methods were used to determine variables associated with, and predictive of, survival and lung function after retransplantation.

RESULTS

Kaplan-Meier survival was 47% +/- 3%, 40% +/- 3%, and 33% +/- 4% at 1, 2, and 3 years, respectively. On multivariable analysis, the predictors of survival included ambulatory status or lack of ventilator support preoperatively (p = 0.005; odds ratio, 1.62; 95% confidence interval, 1.15 to 2.27), followed by retransplantation after 1991 (p = 0.048; odds ratio, 1.41; 95% confidence interval, 1.003 to 1.99). Ambulatory, nonventilated patients undergoing retransplantation after 1991 had a 1-year survival of 64% +/- 5% versus 33% +/- 4% for nonambulatory, ventilated recipients. Eighty-one percent, 70%, 62%, and 56% of survivors were free of bronchiolitis obliterans syndrome at 1, 2, 3, and 4 years after retransplantation, respectively. Factors associated with freedom from stage 3 (severe) bronchiolitis obliterans syndrome at 2 years after retransplantation included an interval between transplants greater than 2 years (p = 0.01), the lack of ventilatory support before retransplantation (p = 0.03), increasing retransplant experience within each center (fifth and higher retransplant patient, p = 0.04), and total center volume of five or more retransplant operations (p = 0.05).

CONCLUSIONS

Nonambulatory, ventilated patients should not be considered for retransplantation with the same priority as other candidates. The best intermediate-term functional results occurred in more experienced centers, in nonventilated patients, and in patients undergoing retransplantation more than 2 years after their first transplant. In view of the scarcity of lung donors, patient selection for retransplantation should remain strict and should be guided by the outcome data reviewed in this article.

Salvage therapy with mycophenolate mofetil for lung transplant bronchiolitis obliterans: importance of dosage

BACKGROUND

Bronchiolitis obliterans (BO) is the most important long-term complication of lung transplantation. Treatment of this condition is often unsuccessful.

METHODS

A patient presented with early BO. Despite OKT3 and the addition of methotrexate, the patient needed persistently high doses of prednisone to maintain lung function at a moderate level. Only the substitution of azathioprine by mycophenolate mofetil (MMF, 3 g/day) made it possible to reduce the dose of prednisone.

RESULTS

Reduction of the dose of MMF to 2 g/day resulted in a deterioration of lung function, which improved impressively after MMF was increased again to 3 g/day.

CONCLUSIONS

MMF may be a valuable therapy for lung transplant BO. However, the use of a high dose, i.e., 3 g/day, may be crucial.

The past, present, and future of lung transplantation

BACKGROUND

The history of lung transplantation from the first human transplant performed in 1963 to the present is reviewed with particular focus on the added challenges because of the contaminated bronchus, exposure of the graft to airborne organisms, the poor blood supply to the bronchus, and the problem of reperfusion pulmonary edema.

METHODS

The technical aspects of single and double sequential lung transplantation are reviewed, as are the current indications for single, double sequential, and heart/lung transplantation. Criteria for lung transplant recipients, in addition to their primary disease are noted, as are absolute and relative contraindications. The standard criteria for donor selection are also reviewed.

RESULTS

The results of single, double sequential, and heart-lung transplantation over the past 10 years as reported by the International Society for Heart and Lung Transplantation Database are reviewed. In addition, the statistics of the lung and heart-lung transplantation program at the University of Colorado Health Sciences Center are reviewed, including the current immunosuppressive regimens and early and late monitoring for infection and rejection. This experience includes 3 early deaths in the first 53 patients for an operative mortality of 5.6%, with a 1-year actuarial survival of 90%.

CONCLUSIONS

During the past decade remarkable improvement in the result of single and double sequential lung transplantation have occurred. As 1-year, actuarial survival is now approaching 90% at some institutions. Living related lobar transplantation, new antirejection agents, chimerism, and xenograft transplantation are areas for continuing and future investigation. The shortage in donor organ supply continues to be a very significant factor in limiting human lung transplantation.

Experimental bronchiolitis obliterans induced by in vivo HVJ-liposome-mediated endothelin-1 gene transfer

BACKGROUND

Bronchiolitis obliterans (OB) is a lesion that results when injury to small conducting airways is repaired by a proliferation of fibrous granulation tissue. Bronchiolitis obliterans has emerged as a main cause of morbidity and mortality in the setting of lung and heart-lung transplantation. Endothelin-1 (ET-1), initially discovered as a vasoconstrictive peptide, has a mitogenic activity on vascular smooth cells and airway epithelial cells. Overproduction of endothelin has been reported in patients with OB or chronic rejection after lung transplantation. It is still undetermined whether locally overexpressed ET-1 has a potential impact in the pathogenesis of OB.

METHODS

We locally overexpressed ET-1 using ultraviolet irradiation-inactivated hemagglutinating virus of Japan (HVJ)-liposome-mediated in vivo gene transfer. Plasmid DNA of prepro-ET-1 and high mobility group 1 protein were coencapsulated in liposomes, and were introduced into airway epithelial cells by HVJ-mediated membrane fusion. Control animals received instillation of HVJ-liposome with an empty expression cassette. To confirm the efficiency of transfection, HVJ liposome with beta-galactosidase gene was introduced. The expression of ET-1 and beta-galactosidase was assessed by immunohistochemistry.

RESULTS

Bronchial epithelium alveolar cells and alveolar macrophage were stained blue (X-Gal) 1 week after in vivo gene transfer of beta-galactosidase gene, indicating beta-gal activity. In animals 1 to 2 weeks after in vivo transfection of prepro-ET-1 gene, hyperplastic connective tissue plaque was seen in the alveolar duct and small conducting airway, indicating histologically distinctive bronchiolitis obliterans. Strong ET-1-like immunoactivities were seen in the airway epithelial, hyperplastic connective tissue, and alveolar cells. No histopathologic changes were seen in the control animals.

CONCLUSIONS

These results suggested that ET-1 may play an important role in the pathogenesis of OB. The effective pharmacologic antagonist or inhibitor may possibly control the progression of disease in patients of OB.

Changes in ventilatory mechanics and diaphragmatic function after lung volume reduction surgery in patients with COPD

BACKGROUND

Lung volume reduction (LVR) has recently been used to treat severe emphysema. About 25% of the volume of each lung is removed with this method. Little is known about the mechanism of functional improvement so a study was undertaken to investigate the changes in ventilatory mechanics and diaphragmatic function in eight patients after LVR.

METHODS

Measurements of work of breathing (WOB), intrinsic positive end expiratory pressure (PEEPi), dynamic compliance (Cdyn), and arterial carbon dioxide tension (PaCO2) were performed on the day before surgery and daily for seven days after surgery, as well as one, three, and six months after surgery. All measurements were performed on spontaneously breathing patients, simultaneously assessing oesophageal pressure via an oesophageal balloon catheter and air flow via a tightly adjusted mask. Diaphragmatic function was evaluated by measuring oesophageal and transdiaphragmatic pressure (Pdi) preoperatively and at one, three, and six months postoperatively.

RESULTS

Mean forced expiratory volume in one second (FEV1) was 23 (3.6)% predicted, and all patients were oxygen dependent before the-operation. One day after LVR the mean decrease in WOB was 0.93 (95% confidence interval (CI) 0.46 to 1.40) joule/l, the mean decrease in PEEPi was 0.61 (95% CI 0.35 to 0.87) kPa, and the mean increase in Cdyn was 182.5 (95% CI 80.0 to 284.2) ml/kPa. Similar changes were found seven days and six months after surgery. PaCO2 was higher on the day after the operation but was significantly reduced six months later. Pdi was increased three and six months after surgery.

CONCLUSIONS

Ventilatory mechanics improved immediately after LVR, probably by decompression of lung tissue and relief of thoracic distension. An improvement in diaphragmatic function three and six months postoperatively also contributes to improved respiratory function after LVR.

Posttransplantation physiologic features of the lung and obliterative bronchiolitis

Obliterative bronchiolitis remains the major obstacle to long-term survival after lung transplantation. Herein we provide a brief review of the key literature as well as our own experience with this condition. Obliterative bronchiolitis has occurred in up to two-thirds of all lung transplant recipients. The characteristic physiologic changes include declines in (1) forced expiratory volume in 1 second, (2) forced vital capacity, and (3) diffusing capacity of the lungs for carbon monoxide. Lung biopsy in patients with obliterative bronchiolitis reveals occlusion of bronchioles in a patchy but extensive distribution. Mucous plugging and bronchiectasis may also be seen. Furthermore, intimal thickening of pulmonary vessels together with mild arteriosclerotic changes of the muscular and elastic pulmonary arterioles may be observed. To date, the main risk factor for the development of obliterative bronchiolitis is recurrent, severe, and persistent acute lung rejection. The recommended management is prevention because the established fibrotic condition may necessitate retransplantation.

Subdural empyema due to Burkholderia cepacia: an unusual complication after lung transplantation for cystic fibrosis

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Obliterative bronchiolitis after lung and heart-lung transplantation

Obliterative bronchiolitis (OB) has emerged as the main cause of morbidity and mortality in the long-term follow-up after lung and heart-lung transplantation. The pathogenesis of OB is multifactorial, with acute rejection and cytomegalovirus infection being the main risk factors for the development of OB. The final common pathway of all inciting events seems to be an alloimmune injury, with subsequent release of immunologic mediators and production of growth factors leading to luminal obliteration and fibrous scarring of the small airways. Analyzing the 14 years of experience in 163 patients at Stanford University, we found a current incidence of bronchiolitis obliterans syndrome or histologically proven OB within the first 3 years after lung and heart-lung transplantation of 36.3%, with an overall prevalence of 58.1% after heart-lung and 51.4% after lung transplantation. Both pulmonary function indices (forced expiratory flow between 25% and 75% of forced vital capacity and forced expiratory volume in 1 second) and transbronchial biopsies have proven helpful in diagnosing bronchiolitis obliterans syndrome or OB at an early stage. Early diagnosis of OB and improved management have achieved survival rates in patients with OB after 1, 3, 5, and 10 years of 83%, 66%, 46%, and 22%, compared with 86%, 83%, 67%, and 67% in patients without OB. Recently, different experimental models have been developed to investigate the cellular and molecular events leading to OB and to evaluate new treatment strategies for this complication, which currently limits the long-term success of heart-lung and lung transplantation.

Recurrence of obliterative bronchiolitis and determinants of outcome in 139 pulmonary retransplant recipients

An international series of pulmonary retransplantation was updated to identify the predictors of outcome and the prevalence and recurrence rate of obliterative bronchiolitis after operation. The study cohort included 139 patients who underwent retransplantation in 34 institutions in North America and Europe between 1985 and 1994. Eighty patients underwent retransplantation because of obliterative bronchiolitis, 34 because of acute graft failure, 13 because of intractable airway complications, 8 because of acute rejection, and 4 because of other indications. Survivors were followed up for a median of 630 days, with 48 patients alive at 1 year, 30 at 2 years, and 16 at 3 years after retransplantation. Actuarial survival was 65% +/- 4% at 1 month, 54% +/- 4% at 3 months, 45% +/- 4% at 1 year, 38% +/- 5% at 2 years, and 36% +/- 5% at 3 years; nonetheless, of 90-day postoperative survivors, 65% +/- 6% were alive 3 years after retransplantation. Life-table and univariate Cox analysis revealed that more recent year of retransplantation (p = 0.009), identical match of ABO blood group (p = 0.01), absence of a donor-recipient cytomegalovirus mismatch (p = 0.04), and being ambulatory immediately before retransplantation (p = 0.04) were associated with survival. By multivariate Cox analysis, being ambulatory before retransplantation was the most significant predictor of survival (p = 0.008), followed by reoperation in Europe (p = 0.044). Complete pulmonary function tests were done yearly in every survivor of retransplantation and bronchiolitis obliterans syndrome stages were assigned. Eleven percent of patients were in stage 3 at 1 year, 20% at 2 years, and 25% at 3 years after retransplantation. Values of forced expiratory volume in 1 second decreased from 1.89 +/- 0.13 L early after retransplantation to 1.80 +/- 0.15 L at 1 year and 1.54 +/- 0.16 L at 2 years (p = 0.006, year 2 versus baseline postoperative value). Most of this decrease occurred in patients who underwent retransplantation because of obliterative bronchiolitis, whereas the pulmonary function of patients who underwent retransplantation because of other conditions did not significantly change. We conclude that survival after pulmonary retransplantation is improving. Optimal results can be obtained in patients who are ambulatory before retransplantation. Compared with recent data after primary lung transplantation, bronchiolitis obliterans syndrome does not appear to recur in an accelerated manner after retransplantation. As long as early mortality as a result of infection can be minimized, pulmonary retransplantation appears to offer a reasonable option in highly selected patients.

Improved results of lung transplantation for patients with cystic fibrosis

Patients with cystic fibrosis pose particular challenges for lung transplant surgeons. Earlier reports from North American centers suggested that patients with cystic fibrosis were at greater risk for heart-lung or isolated lung transplantation than other patients with end-stage pulmonary disease. During a 3 1/2 year period, 44 patients with end-stage lung disease resulting from cystic fibrosis underwent double lung transplantation at this institution. During the same interval, 18 patients with cystic fibrosis died while waiting for lung transplantation. The ages of the recipients ranged from 8 to 45 years, and mean forced expiratory volume in 1 second was 21% predicted. Seven patients had Pseudomonas cepacia bacteria before transplantation. Bilateral sequential implantation with omentopexy was used in all patients. There were no operative deaths, although two patients required urgent retransplantation because of graft failure. Cardiopulmonary bypass was necessary in six procedures in five patients and was associated with an increased blood transfusion requirement, longer postoperative ventilation, and longer hospital stay. Actuarial survival was 85% at 1 year and 67% at 2 years. Infection was the most common cause of death within 6 months of transplantation (Pseudomonas cepacia pneumonia was the cause of death in two patients), and bronchiolitis obliterans was the most common cause of death after 6 months. Actuarial freedom from development of clinically significant bronchiolitis obliterans was 59% at 2 years. Results of pulmonary function tests improved substantially in survivors, with forced expiratory volume in 1 second averaging 78% predicted 2 years after transplantation. Double lung transplantation can be accomplished with acceptable morbidity and mortality in patients with cystic fibrosis.