A prospective evaluation of phrenic nerve injury after lung transplantation: Incidence, risk factors, and analysis of the surgical procedure.

BACKGROUND: Phrenic nerve injury (PNI) is a complication of lung transplantation related to the surgical procedure and associated with increased morbidity. However, the incidence and risk factors, specifically regarding surgical techniques, have not been adequately studied. METHODS: We conducted a prospective single-center study over 4-years, in recipients of lung transplantation with a normal pretransplant phrenic nerve conduction study (PNCS). Diaphragm ultrasound and PNCS were performed in the first 21 postoperative days and PNI was defined when both tests were abnormal. Patients were followed up until hospital discharge. The association between transplant characteristics and PNI was analyzed by using logistic regression models. RESULTS: Two hundred eleven lung grafts implanted in 127 patients were included in the study. After lung transplantation, PNI was diagnosed in 43.3% of the subjects and 29% of the operated hemithorax. Regression logistic model showed that the variables related to PNI were female gender (p = 0.02), bilateral lung transplantation (BLT) (p = 0.001), right lung graft (p = 0.003), clamshell incision (p = 0.01), mediastinal adhesions (p = 0.002), longer operative time (p = 0.003), intraoperative extracorporeal support (p = 0.02), and blood transfusion (p = 0.003). Conversely, age >61 years (p = 0.008) and higher thoracic diameter (p = 0.04) were protective factors. The use of electrocautery, cardiac mechanical retractors, and diaphragmatic traction was not associated with PNI. Morbidity was increased without any difference in mortality. CONCLUSIONS: PNI is a frequent complication after lung transplantation, associated with higher morbidity. Mainly risk factors were age, BLT, female gender, and variables related to surgical difficulties. Lung graft in the right hemithorax and mediastinal adhesiolysis were the most relevant technical variables.

Role of VEGF Polymorphisms in the Susceptibility and Severity of Interstitial Lung Disease.

The search for biomarkers that can help to establish an early diagnosis and prognosis of interstitial lung disease (ILD) is of potential interest. VEGF polymorphisms have been implicated in the development of several lung disorders. Consequently, we assessed, for the first time, the role of VEGF polymorphisms in the susceptibility and severity of ILD. A total of 436 Caucasian ILD patients (244 with idiopathic interstitial pneumonias (IIPs) and 192 with non-IIP) and 536 ethnically-matched healthy controls were genotyped for VEGF rs833061, rs1570360, rs2010963, rs3025020, and rs3025039 polymorphisms by TaqMan assays. Pulmonary function tests were collected from all the patients. VEGF serum levels were determined by ELISA in a subgroup of patients. No VEGF genotype, allele, carrier, or haplotype differences were found between ILD patients and controls as well as between IIP and non-IIP patients. However, an association of rs1570360 with IIP in women and also with lung function in IIP patients was found. None of the VEGF polymorphisms were associated with VEGF levels. In conclusion, our results suggest that VEGF does not seem to play a relevant role in ILD, although rs1570360 may influence the severity of ILD in women and a worse outcome in IIP patients.

Near-normal aerobic capacity in long-term survivors after lung transplantation.

The clinical course of lung transplantation (LT) is diverse: some patients present chronic lung allograft dysfunction (CLAD) and progressive decline in pulmonary function, but others maintain normal spirometric values and active lives. OBJECTIVES: The aim of this study was to elucidate whether long-term LT survivors with normal spirometry achieve normal exercise capacity, and to identify predictive factors of exercise capacity. METHODS: This was a cross-sectional multicentre study, where bilateral LT recipients who survived at least 10 years after LT, with normal spirometry, no diagnosis of CLAD and modified Medical Research Council dyspnoea degree ≤2 underwent cardiopulmonary exercise testing (CPET). RESULTS: 28 LT recipients were included with a mean±sd age of 48.7±13.6 years. Oxygen uptake (V' O2 ) had a mean±sd value of 21.49±6.68 mL·kg-1·min-1 (75.24±15.6%) and the anaerobic threshold was reached at 48.6±10.1% of the V' O2max predicted. The mean±sd heart rate reserve at peak exercise was 17.56±13.6%. The oxygen pulse increased during exercise and was within normal values at 90.5±19.4%. The respiratory exchange ratio exceeded 1.19 at maximum exercise. The median (25-75th percentile) EuroQol-5D score was 1 (0.95-1), indicating a good quality of life. The median (25-75th percentile) International Physical Activity Questionnaire score was 5497 (4007-9832) MET-min·week-1 with 89% of patients reporting more than 1500 MET-min·week-1. In the multivariate regression models, age, sex and diffusing capacity of the lung for carbon monoxide remained significantly associated with V' O2max (mL·kg-1·min-1); haemoglobin and forced expiratory volume in 1 s were significantly associated with maximum work rate (watts), after adjusting for confounders. CONCLUSION: We report for the first time near-normal peak V' O2 values during CPET and normal exercise capacity in long-term LT recipients without CLAD.

Myeloid-Derived Suppressor Cells Are Increased in Lung Transplant Recipients and Regulated by Immunosuppressive Therapy.

Lung transplantation remains as a primary treatment for end-stage lung diseases. Although remarkable improvement has been achieved due to the immunosuppressive protocols, long-term survival for lung transplant recipients (LTR) is still limited. In the last few decades, an increasing interest has grown in the study of dysregulation of immune mechanisms underlying allograft failure. In this regard, myeloid-derived suppressor cells (MDSCs) could play an important role in the promotion of graft tolerance due to their immune regulatory function. Here, we describe for the first time circulating subsets MDSCs from LTR at several time points and we evaluate the relationship of MDSCs with sort-term lung transplant outcomes. Although no effect of MDSCs subsets on short-term clinical events was observed, our results determine that Mo-MDSCs frequencies are increased after acute cellular rejection (ACR), suggesting a possible role for Mo-MDSCs in the development of chronic lung allograft dysfunction (CLAD). Therefore, whether MDSCs subsets play a role as biomarkers of chronic rejection remains unknown and requires further investigations. Also, the effects of the different immunosuppressive treatments on these subpopulations remain under research and further studies are needed to establish to what extend MDSCs immune modulation could be responsible for allograft acceptance.

Endothelial Progenitor Cells as a Potential Biomarker in Interstitial Lung Disease Associated with Rheumatoid Arthritis.

Interstitial lung disease (ILD) increases morbidity and mortality in patients with rheumatoid arthritis (RA). Although the pathogenesis of ILD associated with RA (RA-ILD+) remains poorly defined, vascular tissue is crucial in lung physiology. In this context, endothelial progenitor cells (EPC) are involved in endothelial tissue repair. However, little is known about their implication in RA-ILD+. Accordingly, we aimed to investigate the potential role of EPC related to endothelial damage in RA-ILD+. EPC quantification in peripheral blood from 80 individuals (20 RA-ILD+ patients, 25 RA-ILD- patients, 21 idiopathic pulmonary fibrosis (IPF) patients, and 14 healthy controls) was performed by flow cytometry. EPC were considered as CD34+, CD45low, CD309+ and CD133+. A significant increase in EPC frequency in RA-ILD+ patients, as well as in RA-ILD- and IPF patients, was found when compared with controls (p < 0.001, p = 0.02 and p < 0.001, respectively). RA-ILD+ patients exhibited a higher EPC frequency than the RA-ILD- ones (p = 0.003), but lower than IPF patients (p < 0.001). Our results suggest that EPC increase may represent a reparative compensatory mechanism in patients with RA-ILD+. The degree of EPC frequency may help to identify the presence of ILD in RA patients and to discriminate RA-ILD+ from IPF.

The Spectrum of Interstitial Lung Disease Associated with Autoimmune Diseases: Data of a 3.6-Year Prospective Study from a Referral Center of Interstitial Lung Disease and Lung Transplantation.

Interstitial lung disease (ILD) may occur in patients with a rheumatic autoimmune disease (AD), increasing their risk of morbidity and mortality. However, little is known about the prevalence of AD in patients diagnosed with an ILD. In this prospective study, we determined the spectrum of ILD associated with AD (AD-ILD) among patients sent for assessment to a single clinic of ILD and lung transplantation from a referral center between May 2016 and December 2019. ILD diagnosis was made by pneumologists based on clinical and radiological findings and pulmonary function test abnormalities. All patients with ILD were also assessed by experienced rheumatologists. During the period of assessment, 338 patients were diagnosed with ILD. Among them, 32.8% fulfilled definitions for an AD. Most cases with AD-ILD had a diagnosis of rheumatoid arthritis (27.0%), systemic sclerosis (26.1%) or anti-synthetase syndrome (17.1%). Interestingly, 18% of the patients with AD-ILD were diagnosed as having an interstitial pneumonia with autoimmune features. Antinuclear antibodies and non-specific interstitial pneumonia were the most frequent positive autoantibodies and radiological pattern found in AD-ILD patients, respectively. In conclusion, our study indicates that a high number of ILD patients have a related AD. Consequently, close collaboration among rheumatologists and pneumologists is needed.

Long-term survival of lung transplantation for interstitial lung disease associated with connective tissue diseases: a study of 26 cases from a referral centre.

OBJECTIVES: Interstitial lung disease (ILD) is a leading cause of mortality in patients with connective tissue diseases (CTD). Lung transplantation has become a viable option for patients with end-stage CTD-ILD. However, patients with CTD are often considered suboptimal candidates for lung transplantation because of concerns of worse outcomes. We assessed post-transplant survival of patients with CTD-ILD compared to patients with idiopathic pulmonary fibrosis (IPF). METHODS: Medical records of patients who underwent lung transplantation for CTD-ILD at a single referral centre for lung transplantation in Northern Spain between 1998 and 2018 were reviewed. This cohort was compared with patients with IPF (group-matched for age ±3.3 years, transplant year and use of basiliximab induction previous to transplant). Cumulative survival rates after transplantation were estimated by the Kaplan-Meier method and compared between groups using the log-rank test. RESULTS: We studied 26 patients with CTD-ILD and 26 patients with IPF. The underlying diseases of CTD-ILD patients were rheumatoid arthritis (n=9), scleroderma (n=6), Sjögren's syndrome (n=4), ANCA-associated vasculitis (n=3), anti-synthetase syndrome (n=2), and dermatomyositis, systemic lupus erythematosus (1 each). Baseline characteristics were similar in both groups. CTD-ILD patients experienced acute graft rejection less commonly than those with IPF (32.0% vs. 62.5%; p=0.032). However, a non-statistically significant increased frequency of chronic graft rejection was observed in CTD-ILD patients (20.0% vs. 8.3%; p=0.417). In this regard, the 5-year cumulative survival rates after transplantation was reduced in CTD-ILD (42.4% vs. 65.8%) but the difference did not achieve statistical significance (p=0.075). CONCLUSIONS: Long-term post-transplant survival in Northern Spanish patients with CTD-ILD is reduced compared with IPF.

Baja sensibilidad diagnóstica de los modelos clínicos de predicción de embolia pulmonar / Low diagnostic sensitivity of clinical models for prediction of pulmonary embolism

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