Lung transplantation for cystic fibrosis

The Long Scientific Journey of Sirolimus (Rapamycin): From the Soil of Easter Island (Rapa Nui) to Applied Research and Clinical Trials on β-Thalassemia and Other Hemoglobinopathies

In this review article, we present the fascinating story of rapamycin (sirolimus), a drug able to induce γ-globin gene expression and increased production of fetal hemoglobin (HbF) in erythroid cells, including primary erythroid precursor cells (ErPCs) isolated from β-thalassemia patients. For this reason, rapamycin is considered of great interest for the treatment of β-thalassemia. In fact, high levels of HbF are known to be highly beneficial for β-thalassemia patients. The story of rapamycin discovery began in 1964, with METEI, the Medical Expedition to Easter Island (Rapa Nui). During this expedition, samples of the soil from different parts of the island were collected and, from this material, an antibiotic-producing microorganism (Streptomyces hygroscopicus) was identified. Rapamycin was extracted from the mycelium with organic solvents, isolated, and demonstrated to be very active as an anti-bacterial and anti-fungal agent. Later, rapamycin was demonstrated to inhibit the in vitro cell growth of tumor cell lines. More importantly, rapamycin was found to be an immunosuppressive agent applicable to prevent kidney rejection after transplantation. More recently, rapamycin was found to be a potent inducer of HbF both in vitro using ErPCs isolated from β-thalassemia patients, in vivo using experimental mice, and in patients treated with this compound. These studies were the basis for proposing clinical trials on β-thalassemia patients.

Lung Transplantation in Cystic Fibrosis and the Impact of Extracorporeal Circulation

INTRODUCTION

Lung disease is the major cause of death among cystic fibrosis (CF) patients, affecting 80% of the population. The impact of extracorporeal circulation (ECC) during transplantation has not been fully clarified. This study aimed to evaluate the outcomes of lung transplantation for CF in a single center, and to assess the impact of ECC on survival.

METHODS

We performed a retrospective observational study of all trasplanted CF patients in a single center between 1992 and 2011. During this period, 64 lung transplantations for CF were performed.

RESULTS

Five- and 10-year survival of trasplanted patients was 56.7% and 41.3%, respectively. Pre-transplantation supplemental oxygen requirements and non-invasive mechanical ventilation (NIMV) do not seem to affect survival (P=.44 and P=.63, respectively). Five- and 10-year survival among patients who did not undergo ECC during transplantation was 75.69% and 49.06%, respectively, while in those did undergo ECC during the procedure, 5- and 10-year survival was 34.14% and 29.87%, respectively (P=.001). PaCO₂ is an independent risk factor for the need for ECC.

CONCLUSIONS

The survival rates of CF patients undergoing lung transplantation in our hospital are similar to those described in international registries. Survival is lower among patients receiving ECC during the procedure. PaCO₂ is a risk factor for the need for ECC during lung transplantation.

Lung transplantation for cystic fibrosis: results, indications, complications, and controversies

Survival in patients with cystic fibrosis (CF) has improved dramatically over the past 30 to 40 years, with mean survival now approximately 40 years. Nonetheless, progressive respiratory insufficiency remains the major cause of mortality in CF patients, and lung transplantation (LT) is eventually required. Timing of listing for LT is critical, because up to 25 to 41% of CF patients have died while awaiting LT. Globally, approximately 16.4% of lung transplants are performed in adults with CF. Survival rates for LT recipients with CF are superior to other indications, yet LT is associated with substantial morbidity and mortality (∼50% at 5-year survival rates). Myriad complications of LT include allograft failure (acute or chronic), opportunistic infections, and complications of chronic immunosuppressive medications (including malignancy). Determining which patients are candidates for LT is difficult, and survival benefit remains uncertain. In this review, we discuss when LT should be considered, criteria for identifying candidates, contraindications to LT, results post-LT, and specific complications that may be associated with LT. Infectious complications that may complicate CF (particularly Burkholderia cepacia spp., opportunistic fungi, and nontuberculous mycobacteria) are discussed.

Inflammation, oxidative stress, and cardiovascular disease risk factors in adults with cystic fibrosis

Cystic fibrosis (CF) represents one of a number of localized lung and non-lung diseases with an intense chronic inflammatory component associated with evidence of systemic oxidative stress. Many of these chronic inflammatory diseases are accompanied by an array of atherosclerotic processes and cardiovascular disease (CVD), another condition strongly related to inflammation and oxidative stress. As a consequence of a dramatic increase in long-lived patients with CF in recent decades, the specter of CVD must be considered in these patients who are now reaching middle age and beyond. Buttressed by recent data documenting that CF patients exhibit evidence of endothelial dysfunction, a recognized precursor of atherosclerosis and CVD, the spectrum of risk factors for CVD in CF is reviewed here. Epidemiological data further characterizing the presence and extent of atherogenic processes in CF patients would seem important to obtain. Such studies should further inform and offer mechanistic insights into how other chronic inflammatory diseases potentiate the processes leading to CVDs.

Myocardial infarction in an adult with cystic fibrosis and heart and lung transplant

We present a case of myocardial infarction in a 19 year old female with cystic fibrosis who had a heart and lung transplant performed at the age of four years old. She presented atypically with a one day history of severe, intermittent, central, sharp chest pain, radiating to her back and down her left arm. A coronary angiogram showed proximal stenosis of the left anterior descending artery and right coronary artery. She was treated with percutaneous coronary intervention, involving drug eluting stents to the left anterior descending artery (LAD) and the right coronary artery (RCA). In this study we discuss the pathophysiology, investigations and treatment of cardiac transplant vasculopathy. Although complete reversal of LAD and RCA stenosis was achieved, routine follow-up with coronary angiography and careful control of cardiac risk factors will be important to identify and reduce future restenosis and adverse cardiac events.

Lung transplantation in older patients with cystic fibrosis: analysis of UNOS data

BACKGROUND

The lifespan for patients with cystic fibrosis (CF) is increasing. As a result, greater numbers of older CF patients are presenting for lung transplantation (LTx). The UNOS database provides an opportunity to examine outcomes for this population.

METHODS

We retrospectively reviewed UNOS data to identify 1,637 first-time LTx recipients with the indication of CF between 1999 and 2007. Patients were stratified by quartile age. Our primary end-point was all-cause mortality. Post-transplant survival was compared using Cox proportional hazards regression.

RESULTS

Of the patients who met the inclusion criteria, the distribution by age quartile was as follows: Quartile 1 (Q1), age 7 to 20 years, N = 408; Q2, 21 to 27, N = 470; Q3, 28 to 34, N = 365; and Q4, >or=35, N = 394. Patients in the lowest quartile had the lowest 5-year cumulative survival (43%); 19% lower than for patients in Quartile 4 (age >or=35, cumulative survival = 62%; p < 0.001). On multivariable analysis, patients in Q3 and Q4 had a 38% and 32% reduction in cumulative hazard for death, respectively (reference Q1, age 7 to 20) (hazards ratios: Q3, 0.62 [0.46 to 0.85], p < 0.001; Q4, 0.68 [0.5 to 0.93], p = 0.02). Thirty-day and 1-year cumulative survival were not different among the four quartiles (30-day survival: Q1, 96.4%; Q2, 96.2%; Q3, 96.2%; and Q4, 95.5% [p = 0.94]; 1-year survival: Q1, 83.7%; Q2, 83.1%; Q3, 85.4%; and Q4, 83.4% [p 0.88]). Increasing age was associated with decreases in early post-operative infections, reduction in the cumulative hazard of developing bronchiolitis obliterans (BO) syndrome, and decreases in hospitalizations and treatment for rejection.

CONCLUSIONS

The UNOS database has provided a large series examining survival after LTx in older CF patients. LTx is safe in this group and older age may be protective against infection, rejection and BO syndrome.

Cardiopulmonary bypass for lung transplantation in cystic fibrosis: pilot evaluation of perioperative outcome

OBJECTIVE

The purpose of this study was to determine whether cardiopulmonary bypass (CPB) reduces the incidence of perioperative graft infection after lung transplantation in adults with cystic fibrosis (CF).

DESIGN

Retrospective and observational.

SETTING

University hospital.

PARTICIPANTS

Adults with CF who underwent lung transplantation (1998-2003).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Cohort size was 26: group A (n = 10) who underwent CPB for implantation of both lungs, group B (n = 8) who underwent CPB only for implantation of the second lung, and group C (n = 8) who did not undergo CPB. The 3 cohort subgroups were similar (p > 0.05) in demographics, preoperative lung function, and anesthetic management. Group A had a lower incidence of perioperative pneumonia (p = 0.02). CPB exposure increased transfusion (B > A > C) of fresh frozen plasma and platelets but not packed red blood cells. There were no differences (p > 0.05) in clinical outcome as reflected by duration of mechanical ventilation, tracheal re-intubation, re-exploration for bleeding, sepsis, primary graft dysfunction, renal dysfunction, length of stay, and mortality.

CONCLUSIONS

CPB is associated with decreased incidence of early graft infection after lung transplantation for adult CF when used for implantation of both lungs. This may be because of improved decontamination of the operative field before graft implantation.

Surgical management of pulmonary and gastrointestinal complications in children with cystic fibrosis

PURPOSE OF REVIEW

Cystic fibrosis is a common disorder, affecting as many as 1:2500 Caucasian live births. Despite improved medical management, disease-specific complications are common and are responsible for substantial morbidity and ultimately mortality. Both pulmonary and gastrointestinal complications of cystic fibrosis are well known; however, the complications requiring surgical intervention in the pediatric population are infrequent. We provide a detailed review of the cystic fibrosis-associated pulmonary and gastrointestinal complications and potential surgical options for management in children with cystic fibrosis.

RECENT FINDINGS

Recent operative approaches are described that include application of minimally invasive surgical techniques primarily for intrathoracic disease. Novel medical therapies are also presented. Finally an attempt is made to put in perspective those surgical care advances that have had a benefit on disease outcomes.

SUMMARY

This report will provide the physician caring for the child with cystic fibrosis an understanding of those disease complications that will require surgical consultation and potential operative intervention.