Neutrophil extracellular traps promote fibrous vascular occlusions in chronic thrombosis.

Acute pulmonary embolism generally resolves within 6 months. However, if the thrombus is infected, venous thrombi transform into fibrotic vascular obstructions leading to chronic deep vein thrombosis and/or chronic thromboembolic pulmonary hypertension (CTEPH), but precise mechanisms remain unclear. Neutrophils are crucial in sequestering pathogens; therefore, we investigated the role of neutrophil extracellular traps (NETs) in chronic thrombosis. Because chronic pulmonary thrombotic obstructions are biologically identical to chronic deep venous thrombi, the murine inferior vena cava ligation model was used to study the transformation of acute to chronic thrombus. Mice with staphylococcal infection presented with larger thrombi containing more neutrophils and NETs but less resolution. Targeting NETs with DNase1 diminished fibrosis and promoted thrombus resolution. For translational studies in humans, we focused on patients with CTEPH, a severe type of deep venous and pulmonary artery fibrotic obstruction after thrombosis. Neutrophils, markers of neutrophil activation, and NET formation were increased in CTEPH patients. NETs promoted the differentiation of monocytes to activated fibroblasts with the same cellular phenotype as fibroblasts from CTEPH vascular occlusions. RNA sequencing of fibroblasts isolated from thrombo-endarterectomy specimens and pulmonary artery biopsies revealed transforming growth factor-ß (TGF-ß) as the central regulator, a phenotype which was replicated in mice with fibroblast-specific TGF-ß overactivity. Our findings uncover a role of neutrophil-mediated inflammation to enhance TGF-ß signaling, which leads to fibrotic thrombus remodeling. Targeting thrombus NETs with DNases may serve as a new therapeutic concept to treat thrombosis and prevent its sequelae.

Clinical relevance of lung transplantation for COVID-19 ARDS: a nationwide study.

BACKGROUND: Although the number of lung transplantations (LTx) performed worldwide for COVID-19 induced acute respiratory distress syndrome (ARDS) is still low, there is general agreement that this treatment can save a subgroup of most severly ill patients with irreversible lung damage. However, the true proportion of patients eligible for LTx, the overall outcome and the impact of LTx to the pandemic are unknown. METHODS: A retrospective analysis was performed using a nationwide registry of hospitalised patients with confirmed severe acute respiratory syndrome coronavirus type 2 (SARS-Cov-2) infection admitted between January 1, 2020 and May 30, 2021 in Austria. Patients referred to one of the two Austrian LTx centers were analyzed and grouped into patients accepted and rejected for LTx. Detailed outcome analysis was performed for all patients who received a LTx for post-COVID-19 ARDS and compared to patients who underwent LTx for other indications. RESULTS: Between January 1, 2020 and May 30, 2021, 39.485 patients were hospitalised for COVID-19 in Austria. 2323 required mechanical ventilation, 183 received extra-corporeal membrane oxygenation (ECMO) support. 106 patients with severe COVID-19 ARDS were referred for LTx. Of these, 19 (18%) underwent LTx. 30-day mortality after LTx was 0% for COVID-19 ARDS transplant recipients. With a median follow-up of 134 (47-450) days, 14/19 patients are alive. CONCLUSIONS: Early referral of ECMO patients to a LTx center is pivotal in order to select patients eligible for LTx. Transplantation offers excellent midterm outcomes and should be incorporated in the treatment algorithm of post-COVID-19 ARDS.

Microvascular Disease in Chronic Thromboembolic Pulmonary Hypertension: Hemodynamic Phenotyping and Histomorphometric Assessment.

BACKGROUND: Pulmonary endarterectomy (PEA) is the gold standard treatment for patients with operable chronic thromboembolic pulmonary hypertension. However, persistent pulmonary hypertension (PH) after PEA remains a major determinant of poor prognosis. A concomitant small-vessel arteriopathy in addition to major pulmonary artery obstruction has been suggested to play an important role in the development of persistent PH and survival after PEA. One of the greatest unmet needs in the current preoperative evaluation is to assess the presence and severity of small-vessel arteriopathy. Using the pulmonary artery occlusion technique, we sought to assess the presence and degree of small-vessel disease in patients with chronic thromboembolic pulmonary hypertension undergoing PEA to predict postoperative outcome before surgery. METHODS: Based on pulmonary artery occlusion waveforms yielding an estimate of the effective capillary pressure, we partitioned pulmonary vascular resistance in larger arterial (upstream resistance [Rup]) and small arterial plus venous components (downstream resistance) in 90 patients before PEA. For validation, lung wedge biopsies were taken from nonobstructed and obstructed lung territories during PEA in 49 cases. Biopsy sites were chosen according to the pulmonary angiogram still frames that were mounted in the operating room. All vessels per specimen were measured in each patient. Percent media (%MT; arteries) and intima thickness (%IT; arteries, veins, and indeterminate vessels) were calculated relative to external vessel diameter. RESULTS: Decreased Rup was an independent predictor of persistent PH (odds ratio per 10%, 0.40 [95% CI, 0.23-0.69]; P=0.001) and survival (hazard ratio per 10%, 0.03 [95% CI, 0.00-0.33]; p=0.004). Arterial %MT and %IT of nonobstructed lung territories and venous %IT of obstructed lung territories were significantly increased in patients with persistent PH and nonsurvivors. Rup correlated inversely with %MT (r=-0.72, P<0.001) and %IT (r=-0.62, P<0.001) of arteries from nonobstructed lung territories and with %IT (r=-0.44, P=0.024) of veins from obstructed lung territories. Receiver operating characteristic analysis disclosed that Rup <66% predicted persistent PH after PEA, whereas Rup <60% identified patients with poor prognosis after PEA. CONCLUSIONS: Pulmonary artery occlusion waveform analysis with estimation of Rup seems to be a valuable technique for assessing the degree of small-vessel disease and postoperative outcome after PEA in chronic thromboembolic pulmonary hypertension.

Outcomes with alemtuzumab induction therapy in lung transplantation: a comprehensive large-scale single-center analysis.

Alemtuzumab is a monoclonal antibody targeting CD52, increasingly used as induction therapy after transplantation. The aim of this study was to analyze the outcomes of alemtuzumab induction therapy followed by a low-dose maintenance immunosuppression in a large single-center cohort of lung transplant recipients. All patients, who received alemtuzumab induction followed by a low-dose maintenance immunosuppression were included in the analysis. Short- and long-term outcomes were analyzed. 721 lung transplant recipients, transplanted between January 2008 and June 2019, were included in this retrospective study. Freedom from higher-grade ACR at 1, 5, and 10 years was 98%, 96%, and 96%, respectively. Thirty-nine patients (5%) developed clinical AMR. Twenty-one percent of patients developed high-grade CKD. A total of 1488 infections were recorded. Sixteen percent were diagnosed within the first 3 months. Sixty-two patients (9%) developed a malignancy during follow-up. Freedom from CLAD at 1, 5, and 10 years was 94%, 72%, and 53%, respectively. Overall survival rates at 1, 5, and 10 years were 85%, 71%, and 61%, respectively. Alemtuzumab induction combined with a low-dose tacrolimus protocol is safe and associated with low rates of acute and chronic rejection, as well as an excellent long-term survival.

Dying blood mononuclear cell secretome exerts antimicrobial activity.

BACKGROUND: Several activities are attributed to antimicrobial peptides (AMPs), including bacterial killing, leucocyte recruitment and angiogenesis. Despite promises of advanced cellular therapies for treatment of diabetic foot ulcer, it is currently accepted that paracrine factors rather than cellular components are causative for the observed effects. Whether AMPs are present in the mononuclear cell (MNC) secretome (MNC-sec) of white blood cells that are beneficial in experimental wound healing is not known. MATERIALS AND METHODS: Antimicrobial activity of the secretomes of nonirradiated (MNC-sec) and γ-irradiated MNCs (MNC-sec rad) was analysed by microdilution assay. AMPs were determined by quantitative real-time PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Whether human MNC-sec rad causes AMP secretion in vivo was examined in an experimental rat model. Image flow cytometry was used to determine the type of cell death induced in MNCs after exposure to γ-radiation. RESULTS: The antimicrobial activity assay revealed a bactericidal activity of MNC-sec rad and to a lesser degree also of MNC-sec. Image flow cytometry showed that γ-irradiation of MNCs induced early apoptosis followed mainly by necroptosis. RT-PCR and ELISA revealed a high abundance of different AMPs in the secretome of MNCs. In addition, human MNC-sec elicited an increase in de novo endogenous AMP production in rats in vivo. CONCLUSION: We provide evidence that the secretome of MNCs has direct and indirect positive effects on the immune defence system, including augmentation of antibacterial properties. Our data further suggest that necroptosis could play a key role for the release of paracrine factors and the therapeutic action of MNC-sec rad.

A rare indication for lung transplantation - pulmonary alveolar microlithiasis: institutional experience of five consecutive cases.

BACKGROUND: Pulmonary alveolar microlithiasis (PAM) is a rare lung disease caused by calcifications within the alveolar space. The only known effective treatment for an end-stage PAM is lung transplantation (LuTX). METHODS: We performed a retrospective chart review of all individuals that underwent lung transplantation at our center between 1989 and 2013. Five consecutive patients with PAM were identified. RESULTS: Four females and one male with a mean age of 46.3 yr were identified. Extracorporeal membrane oxygenation (ECMO) support was required intraoperatively in four cases and post-operatively in one case. Mean post-operative intubation time was 3.3 (range, 2-5) d and mean intensive care unit (ICU) stay was 8.3 (range, 4-12) d. No intraoperative complications were observed. One early patient (operated in 1995) underwent acute re-transplantation on the second post-operative day (POD) and died from sepsis on the 11 POD. In one patient reperfusion edema was observed requiring a prolonged weaning process. No other severe perioperative complications were observed. Four of five patients are currently still alive with normal follow-up parameters. No recurrence of PAM was observed. CONCLUSIONS: Lung transplantation is a feasible therapy option in patients with end-stage PAM showing good post-operative results comparable to other indications for LuTX.

Lung transplantation in patients with incidental early stage lung cancer-institutional experience of a high volume center.

BACKGROUND: Incidentally discovered lung cancers in lung transplant (LuTX) recipients are rare but may affect outcome. We aim to report our single center experience with incidence, management, and survival of patients with previously unverified primary lung cancer discovered at the time of LuTX. METHODS: A total of 1262 patients undergoing LuTX between 1989 and 2012 were retrospectively analyzed in our prospective database. RESULTS: Patients identified were six men and five women with a mean age of 54.4±9.9 years. The indication for LuTX was COPD (n=9), pulmonary fibrosis (n=1), and cystic fibrosis (n=1). Histological diagnosis of the explanted lung revealed adenocarcinoma in six, squamous cell carcinoma in three, and lepidic predominant adenocarcinoma in two cases, respectively. Staging revealed stage IA (pT1a/b pN0) in eight and IB (pT2a pN0) in two cases and one patient in stage IIA (pT1b pN1). Subsequent cancer staging after LuTX revealed no metastasis. Immunosuppression was adjusted and no adjuvant chemo- or radiotherapy was administered. The 5-year survival rate was 90.5% with no detection of recurrence. CONCLUSION: In patients with incidentally detected early stage lung cancer at the time of LuTX, rates of recurrence and survival based on this sample appear to be acceptable.

Extracorporeal CO2 removal as bridge to lung transplantation in life-threatening hypercapnia.

In patients awaiting lung transplantation (LTX), adequate gas exchange may not be sufficiently achieved by mechanical ventilation alone if acute respiratory decompensation arises. We report on 20 patients with life-threatening hypercapnia who received extracorporeal CO2 removal (ECCO2-R) by means of the interventional lung assist (ILA®, Novalung) as bridge to LTX. The most common underlying diagnoses were bronchiolitis obliterans syndrome, cystic fibrosis, and idiopathic pulmonary fibrosis, respectively. The type of ILA was pumpless arteriovenous or pump-driven venovenous (ILA activve®, Novalung) in 10 patients each. ILA bridging was initiated in 15 invasively ventilated and five noninvasively ventilated patients, of whom one had to be intubated prior to LTX. Hypercapnia and acidosis were effectively corrected in all patients within the first 12 h of ILA therapy: PaCO2 declined from 109 (70-146) to 57 (45-64) mmHg, P < 0.0001; pH increased from 7.20 (7.06-7.28) to 7.39 (7.35-7.49), P < 0.0001. Four patients were switched to extracorporeal membrane oxygenation due to progressive hypoxia or circulatory failure. Nineteen patients (95%) were successfully transplanted. Hospital and 1-year survival was 75 and 72%, respectively. Bridging to LTX with ECCO2-R delivered by arteriovenous pumpless or venovenous pump-driven ILA is feasible and associated with high transplantation and survival rates.

Surgical specimens, haemodynamics and long-term outcomes after pulmonary endarterectomy.

BACKGROUND: Chronic thromboembolic pulmonary hypertension is surgically curable by pulmonary endarterectomy (PEA). It is unclear whether PEA impacts primarily steady state right ventricular afterload (ie, pulmonary vascular resistance (PVR)) or pulsatile right ventricular afterload (ie, pulmonary arterial compliance (C(PA))). Our objectives were to (1) quantify PEA specimens and measure the impact of PEA on PVR and C(PA) in a structure/function study and (2) analyse the effects of haemodynamic changes on long-term survival/freedom of lung transplantation in an outcome study. METHODS: Thrombi were laid out, weighed, photographed and measured. PVR, C(PA) and resistance times compliance (RC-time) were assessed at baseline, within 4 days after PEA ('immediately postoperative') and 1 year after PEA, in 110 consecutive patients who were followed for 34.5 (11.9; 78.3) months. RESULTS: Lengths and numbers of PEA specimen tails were inversely correlated with immediate postoperative PVR (p<0.0001, r=-0.566; p<0.0001, r=-0.580). PVR and C(PA) normalised immediately postoperatively while RC-time remained unchanged. Immediate postoperative PVR was the only predictor of long-term survival/freedom of lung transplantation (p<0.0001). Patients with immediate postoperative PVR<590 dynes.s.cm(-5) had better long-term outcomes than patients with PVR≥590 dynes.s.cm(-5) (p<0.0001, respectively). CONCLUSIONS: PEA immediately decreased PVR and increased C(PA) under a constant RC-time. However, immediate postoperative PVR was the only predictor of long-term survival/freedom of lung transplantation. Our study confirms the importance of a complete, bilateral surgical endarterectomy. Low PVR measured immediately postoperative predicts excellent long-term outcome.

Thymomas and thymic carcinomas: prognostic factors and multimodal management.

BACKGROUND: Thymomas and thymic carcinomas are rare malignant tumors. We report the experience with the resection and multimodal treatment at a single department in Central Europe in the years 2001 to 2010. OBJECTIVE: We sought to determine prognostic factors in this patient population. METHODS: A 10-year retrospective analysis of 84 resections on 72 patients for thymomas/thymic carcinomas or their recurrences was performed. RESULTS: Patients admitted to a single thoracic surgery center presented with Masaoka-Koga stage I (29.2%), II (43.1%), III (13.9%), and IV (13.9%). In approximately 88.9% of cases, a complete resection could be reached. Using overall survival as an outcome measure, the 5-year survival rate was 87%. Of all the cases presented, 9.7% cases showed tumor recurrence and 6.9% cases showed tumor progression. There was decreased survival rate with increasing Masaoka-Koga stage (p = 0.017) and incomplete resection (p < 0.001). CONCLUSION: Completeness of resection and Masaoka-Koga stage were significant prognostic factors. Multidisciplinary treatments of patients with thymoma or thymic carcinoma result in good patient care, and global efforts with larger number of patients are needed to elucidate more about the biology, diagnosis, and treatment of these tumors.

Left Ventricular Filling Pressure in Chronic Thromboembolic Pulmonary Hypertension.

BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by obstruction of major pulmonary arteries with organized thrombi. Clinical risk factors for pulmonary hypertension due to left heart disease including metabolic syndrome, left-sided valvular heart disease, and ischemic heart disease are common in CTEPH patients. OBJECTIVES: The authors sought to investigate prevalence and prognostic implications of elevated left ventricular filling pressures (LVFP) in CTEPH. METHODS: A total of 593 consecutive CTEPH patients undergoing a first diagnostic right and left heart catheterization were included in this study. Mean pulmonary arterial wedge pressure (mPAWP) and left ventricular end-diastolic pressure (LVEDP) were utilized for assessment of LVFP. Two cutoffs were applied to identify patients with elevated LVFP: 1) for the primary analysis mPAWP and/or LVEDP >15 mm Hg, as recommended by the current pulmonary hypertension guidelines; and 2) for the secondary analysis mPAWP and/or LVEDP >11 mm Hg, representing the upper limit of normal. Clinical and echocardiographic features, and long-term mortality were assessed. RESULTS: LVFP was >15 mm Hg in 63 (10.6%) and >11 mm Hg in 222 patients (37.4%). Univariable logistic regression analysis identified age, systemic hypertension, diabetes, atrial fibrillation, calcific aortic valve stenosis, mitral regurgitation, and left atrial volume as significant predictors of elevated LVFP. Atrial fibrillation, calcific aortic valve stenosis, mitral regurgitation, and left atrial volume remained independent determinants of LVFP in adjusted analysis. At follow-up, higher LVFPs were measured in patients who had meanwhile undergone pulmonary endarterectomy (P = 0.002). LVFP >15 mm Hg (P = 0.021) and >11 mm Hg (P = 0.006) were both associated with worse long-term survival. CONCLUSIONS: Elevated LVFP is common, appears to be due to comorbid left heart disease, and predicts prognosis in CTEPH.

Lung transplantation in children and young adults: a 20-year single-centre experience.

Lung transplantation in adults is an accepted therapeutic option, whereas there is ongoing debate on its positive impact on survival in children. We report our experience of the first 20 yrs of paediatric lung transplantation at a single centre in Austria. Patient survival, organ survival and freedom from bronchiolitis obliterans were estimated by Kaplan-Meier curves. Pre- and post-transplant parameters were assessed and their influence on patient and organ survival evaluated by univariate tests and stepwise multivariate analyses. A total of 55 transplantations were performed in 43 patients. 1- and 5-yr patient survival rates were 72.1% and 60.6%, respectively, and 52.6% of patients were found to be free from bronchiolitis obliterans syndrome at 5 yrs post-transplant. Analysing different eras of transplantation suggests an improvement over the years with a 5-yr survival rate of 70.6% in the second decade. A positive effect of pre-transplant diabetes mellitus and immunosuppression was found with the newer drug tacrolimus, and a negative effect of pre-transplant in-hospital admission was reported. A high rate of successful re-transplantation prolonged total patient survival.

Cervical Repair of Iatrogenic Tracheobronchial Injury by Tracheal T-Incision.

BACKGROUND: Tracheobronchial injury is a rare but potentially life-threatening condition. Various surgical treatment options have been described for symptomatic patients with full-thickness injury. However, studies comprising a meaningful number of patients are sparse. METHODS: We retrospectively analyzed all patients who received surgical repair of tracheobronchial injury between January 1999 and May 2021 at the Department of Thoracic Surgery, Medical University of Vienna. Patient characteristics, surgical variables, postoperative morbidity, and mortality were retrieved and analyzed. RESULTS: Fifty patients with a median age of 68 years (range, 17-88) were included in the analysis. The etiologies of the iatrogenic tracheobronchial injuries were emergency intubation (48%), elective percutaneous dilatation tracheostomy (38%), or elective intubation (14%). The most common location of tracheobronchial injuries was distal third (28%) with a median length of 50 mm (range, 20-100 mm). The surgical approach was cervicotomy in 52%, thoracotomy in 38%, sternotomy in 2%, and combined approaches in 8% of cases. Moreover, intraoperative venovenous (n = 4) or venoarterial (n = 2) extracorporeal membrane oxygenation support was required in 12% of cases. Procedure-related mortality was 0%. However, as patients with tracheobronchial injury usually have severe comorbidities, the rate of patients discharged alive from the intensive care unit was only 66%. The median follow-up period of discharged patients was 5.5 months (range, 0.7-209). Airway stenosis or dehiscence was not observed in any patient. CONCLUSIONS: Surgical repair of tracheobronchial injuries can be performed safely with a low procedure-related morbidity. If possible, the less-invasive cervical access should be preferred for patients with tracheobronchial injury, even for injuries extending to the main bronchi.

EGR1 Is Implicated in Right Ventricular Cardiac Remodeling Associated with Pulmonary Hypertension.

BACKGROUND: Pulmonary hypertension (PH) is a vasoconstrictive disease characterized by elevated mean pulmonary arterial pressure (mPAP) at rest. Idiopathic pulmonary arterial hypertension (iPAH) and chronic thromboembolic pulmonary hypertension (CTEPH) represent two distinct subtypes of PH. Persisting PH leads to right ventricular (RV) hypertrophy, heart failure, and death. RV performance predicts survival and surgical interventions re-establishing physiological mPAP reverse cardiac remodeling. Nonetheless, a considerable number of PH patients are deemed inoperable. The underlying mechanism(s) governing cardiac regeneration, however, remain largely elusive. METHODS: In a longitudinal approach, we profiled the transcriptional landscapes of hypertrophic RVs and recovered hearts 3 months after surgery of iPAH and CTEPH patients. RESULTS: Genes associated with cellular responses to inflammatory stimuli and metal ions were downregulated, and cardiac muscle tissue development was induced in iPAH after recovery. In CTEPH patients, genes related to muscle cell development were decreased, and genes governing cardiac conduction were upregulated in RVs following regeneration. Intriguingly, early growth response 1 (EGR1), a profibrotic regulator, was identified as a major transcription factor of hypertrophic RVs in iPAH and CTEPH. A histological assessment confirmed our biocomputational results, and suggested a pivotal role for EGR1 in RV vasculopathy. CONCLUSION: Our findings improved our understanding of the molecular events driving reverse cardiac remodeling following surgery. EGR1 might represent a promising candidate for targeted therapy of PH patients not eligible for surgical treatment.

Larger pulmonary artery to ascending aorta ratios are associated with decreased survival of patients undergoing pulmonary endarterectomy.

Objectives: The ratio of pulmonary artery (PA) and ascending aorta (AA) diameters has recently been shown to be a useful indicator for disease severity and predictor of outcome in patients with pulmonary hypertension and heart failure. This study aimed at evaluating the applicability of this ratio for perioperative risk assessment of patients with chronic thromboembolic pulmonary hypertension undergoing pulmonary endarterectomy. Methods: In this retrospective cohort study on 149 patients undergoing pulmonary endarterectomy between 2013 and 2020, the preoperative PA to AA ratio was analyzed on axial computed tomography. Variables of pulmonary hemodynamic status were assessed during preoperative right heart catheterization and postoperative Swan-Ganz catheter measurements. Perioperative survival was analyzed by Kaplan-Meier method and log-rank tests. Results: Preoperative computed tomography measurements showed a median AA diameter of 31 mm (range, 19-47 mm), and a median PA diameter of 36 mm (range, 25-55 mm). The calculated median PA to AA ratio was 1.13 (range, 0.79-1.80). PA to AA ratio correlated positively with PA pressure (systolic, r = 0.352 [P < .001]; diastolic, r = 0.406 [P < .001]; mean, r = 0.318 [P < .001]) and inversely with age (r = -0.484 [P < .001]). Univariable Cox regression analysis identified PA diameter (P = .008) as a preoperative parameter predictive of survival. There was a significant difference (log-rank P = .037) in 30-day survival probability for patients with lower PA to AA ratios (<1.136; survival probability, 97.4%) compared with patients with higher ratios (>1.136; survival probability, 88.9%). Conclusions: PA to AA ratio shows a correlation with other variables associated with pulmonary hypertension. In addition, patients with higher PA to AA ratios have lower survival probabilities after PEA. Further analysis of PA to AA ratio on the selection of chronic thromboembolic pulmonary hypertension for different treatment modalities-pulmonary endarterectomy, medical therapy, and or balloon pulmonary angioplasty-is warranted.

Long-term Survival After Salvage Surgery for a Giant Primary Rib Osteosarcoma.

A 29-year-old woman with a primary rib osteosarcoma declined treatment and was readmitted 20 months later in life-threatening condition caused by major local tumor progression with severe mediastinal shifting, and without distant metastases. She underwent extended tumor resection with palliative intent and recovered well after a prolonged course with post-pneumonectomy empyema. Further treatment was declined, and she presented again 4.5 years later with local chest wall recurrence that was completely resected. Currently, 7 years after diagnosis, the patient is free from disease. In this rare case, salvage surgery was associated with an unexpected favorable long-term outcome.

Efficacy and Safety of Percutaneous Pulmonary Artery Subtotal Occlusion and Chronic Total Occlusion Intervention in Chronic Thromboembolic Pulmonary Hypertension.

[Figure: see text].

Donor ventilation parameters as predictors for length of mechanical ventilation after lung transplantation: Results of a prospective multicenter study.

BACKGROUND: The evaluation of donor lungs heavily depends on the subjective judgment of the retrieval surgeon. As a consequence, acceptance rates vary significantly among transplant centers. We aimed to determine donor ventilation parameters in a prospective study and test if they could be used as objective quality criteria during organ retrieval. METHODS: A prospective evaluation of lung donors was performed in 3 transplant centers. Ventilation parameters were collected at the time of retrieval using a standardized ventilation protocol. Recipient length of mechanical ventilation (LMV) was defined as the primary end point, and collected data was used to build linear models predicting LMV. RESULTS: In total, 166 donors were included in this study. Median LMV after transplantation was 32 hours (interquartile range: 20-63 hours). Peak inspiratory pressure and dynamic compliance (Cdyn) at the time of retrieval, but not the partial pressure of oxygen/fraction of inspired oxygen (P/F) ratio, correlated with recipient LMV in Spearman correlations (r = 0.280, p = 0.002; r = -0.245, p = 0.003; and r = 0.064, p = 0.432, respectively). Linear models were built to further evaluate the impact of donor ventilation parameters on LMV. The first model was based on donor P/F ratio, donor age, donor intubation time, donor smoking history, donor partial pressure of carbon dioxide, aspiration, chest trauma, and pathologic chest X-ray. This model performed poorly (multiple R-squared = 0.063). In a second model, donor ventilation parameters were included, and Cdyn was identified as the strongest predictor for LMV. The third model was extended by recipient factors, which significantly improved the robustness of the model (multiple R-squared = 0.293). CONCLUSION: In this prospective evaluation of donor lung parameters, currently used donor quality criteria poorly predicted recipient LMV. Our data suggest that Cdyn is a strong donor-bound parameter to predict short-term graft performance; however, recipient factors are similarly relevant.

Ventilation parameters and early graft function in double lung transplantation.

BACKGROUND: Currently, the primary graft dysfunction (PGD) score is used to measure allograft function in the early post-lung transplant period. Although PGD grades at later time points (T48 hours and T72 hours) are useful to predict mid- and long-term outcomes, their predictive value is less relevant within the first 24 hours after transplantation. This study aimed to evaluate the capability of PGD grades to predict prolonged mechanical ventilation (MV) and compare it with a model derived from ventilation parameters measured on arrival at the intensive care unit (ICU). METHODS: A retrospective single-center analysis of 422 double lung transplantations (LTxs) was performed. PGD was assessed 2 hours after arrival at ICU, and grades were associated with length of MV (LMV). In addition, peak inspiratory pressure (PIP), ratio of the arterial partial pressure of oxygen to fraction of inspired oxygen (P/F ratio), and dynamic compliance (cDyn) were collected, and a logistic regression model was created. The predictive capability for prolonged MV was calculated for both (the PGD score and the model). In a second step, the created model was externally validated using a prospective, international multicenter cohort including 102 patients from the lung transplant centers of Vienna, Toronto, and Budapest. RESULTS: In the retrospective cohort, a high percentage of extubated patients was reported at 24 hours (35.1%), 48 hours (68.0%), and 72 hours (80.3%) after transplantation. At T0 (time point defined as 2 hours after arrival at the ICU), patients with PGD grade 0 had a shorter LMV with a median of 26 hours (interquartile range [IQR]: 16-47 hours) than those with PGD grade 1 (median: 42 hours, IQR: 27-50 hours), PGD grade 2 (median: 37.5 hours, IQR: 15.5-78.5 hours), and PGD grade 3 (median: 46 hours, IQR: 27-86 hours). However, IQRs largely overlapped for all grades, and the value of PGD to predict prolonged MV was poor. A total of 3 ventilation parameters (PIP, cDyn, and P/F ratio), determined at T0, were chosen on the basis of clinical reasoning. A logistic regression model including these parameters predicted prolonged MV (>72 hours) with an optimism-corrected area under the curve (AUC) of 0.727. In the prospective validation cohort, the model proved to be stable and achieved an AUC of 0.679. CONCLUSIONS: The prediction model reported in this study combines 3 easily obtainable variables. It can be employed immediately after LTx to quantify the risk of prolonged MV, an important early outcome parameter.

Elevated HSP27, HSP70 and HSP90 alpha in chronic obstructive pulmonary disease: markers for immune activation and tissue destruction.

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death. Although the underlying pathomechanism remains poorly understood, COPD is accompanied by increased cellular stress and inflammation. We investigated serum contents of heat shock proteins (HSP 27, 60, 70, 90 alpha), 20S proteasomes, C-reactive protein (CRP), and interleukin-6 (IL-6) in patients with mild or severe COPD, healthy smokers and nonsmokers. HSP27, HSP70 and HSP90 alpha were significantly altered in patients suffering from COPD as compared to controls. HSP27 and HSP70 are potential novel serum markers for the diagnosis of COPD in the smoking population. This is the first study to demonstrate elevated serum levels of the described heat shock proteins in patients with COPD. We showed sensitivity and specificity of serum HSP27 and HSP70 as diagnostic markers for COPD.