Use of letermovir for cytomegalovirus primary prophylaxis in lung transplant recipients.

BACKGROUND: Cytomegalovirus (CMV) is a driver of negative outcomes after lung transplant (LTX) and primary prophylaxis (PPX) with valganciclovir (VGC) is standard-of-care. VGC is associated with myelosuppression, prompting interest in letermovir (LTV). METHODS: Adults receiving LTX between April 1, 2015, and July 30, 2022, at our institution were evaluated. Patients were excluded if low CMV risk (D-/R-), survived <90 days post-LTX, or transferred care before PPX withdrawal. Primary outcomes were leukopenia (white blood cell count [WBC] ≤ 3.0 × 109/L), severe leukopenia (WBC ≤ 2.0 × 109/L), and neutropenia (absolute neutrophil count ≤ 1500 cells/µL) requiring granulocyte-colony stimulating factor (GCSF) on PPX. Secondary outcomes included breakthrough CMV infection and post-PPX CMV infection. RESULTS: 204 patients met inclusion criteria: 175 patients on VGC and 29 patients on LTV (after VGC conversion). Most patients received bilateral LTX (62.7%) with non-lymphocyte-depleting induction (96.6%) and moderate-risk serostatus (D+/R+, 48.5%). Patients transitioned from VGC to LTV after a mean of 178 days (SD 80.8 days) post-transplant. Patients on VGC experienced significantly more leukopenia (82.3% vs. 58.6%, p = 0.008), severe leukopenia (57.1% vs. 31.0%, p = 0.016), and neutropenia requiring GCSF (70.9% vs. 51.7%, p = 0.048). Breakthrough (5.7% vs. 3.4%, p = 0.955) and post-PPX (24.6% vs. 37.9%, p = 0.199) infections were similar. A subgroup analysis of patients with high-risk serostatus showed similar trends, though did not reach statistical significance. CONCLUSIONS: In this single-center study, the incidence of leukopenia and neutropenia requiring GCSF were reduced with LTV compared to VGC. Breakthrough and post-PPX infections were not significantly different. This evidence suggests that LTV has comparable efficacy with reduced myelosuppression compared to VGC in LTX recipients, and may be an appropriate alternative for PPX.

Predictors of Cytomegalovirus Recurrence Following Cessation of Posttransplant Prophylaxis.

INTRODUCTION: Cytomegalovirus (CMV) infection is associated with a poor prognosis after lung transplantation, and donor and recipient CMV serostatus is a risk factor for reactivation. CMV prophylaxis is commonly administered in the first year following transplantation to reduce CMV infection; however, the risk factors for long-term reactivation remain unclear. We investigated the timing and risk factors of CMV infection after prophylactic administration. METHODS: This study was a retrospective review of the institutional lung transplantation database from June 2014 to June 2022. Data on patient characteristics, pretransplantation laboratory values, postoperative outcomes, and CMV infection were collected. Donor CMV-IgG-positive and recipient CMV-IgG-negative groups were defined as the CMV mismatch group. RESULTS: During the study period, 257 patients underwent lung transplantation and received a prophylactic dose of valganciclovir hydrochloride for up to 1 y. CMV infection was detected in 69 patients (26.8%): 40 of 203 (19.7%) in the non-CMV mismatch group and 29 of 54 (53.7%) in the CMV mismatch group (P < 0.001). CMV infection after prophylaxis occurred at a median of 425 and 455 d in the CMV mismatch and non-CMV mismatch groups, respectively (P = 0.07). Multivariate logistic regression analysis revealed that preoperative albumin level (odds ratio [OR] = 0.39, P = 0.04), CMV mismatch (OR = 15.7, P < 0.001), and donor age (OR = 1.05, P = 0.009) were significantly associated with CMV infection. CONCLUSIONS: CMV mismatch may have increased the risk of CMV infection after lung transplantation, which decreased after prophylaxis. In addition to CMV mismatch, low preoperative albumin level and donor age were independent predictors of CMV infection.

Primary graft dysfunction grade correlates with acute kidney injury stage after lung transplantation.

Background: Primary graft dysfunction (PGD) and acute kidney injury (AKI) are major early complications of lung transplantation and are associated with increased mortality. Lung injury after PGD can contribute to renal dysfunction; however, the association between PGD and AKI severity has not been thoroughly investigated. We analyzed the association between PGD grading and AKI staging, and the impact of AKI on subsequent changes to chronic kidney disease (CKD), including glomerular filtration rate (GFR), over time. Methods: This was a retrospective review of a single-center lung transplantation database between January 2018 and June 2022. AKI and GFR categories were classified according to the Kidney Disease: Improving Global Outcomes criteria. Spearman's and Kaplan-Meier tests were used to compare disease severity and assess survival. Results: In a total of 206 patients: 119 (57.8%), 25 (12.1%), 34 (16.5%), and 28 (13.6%) had PGD grades 0, 1, 2, and 3, respectively; 96 (46.6%), 47 (22.8%), 27 (13.1%), and 36 (17.5%) had AKI stages 0, 1, 2, and 3, respectively. Twenty-one of the 28 patients (75.0%) with PGD grade 3 had AKI stage 3. There was a significant correlation between PGD grade and AKI stage (P<0.001). There was also a significant correlation between AKI stage and GFR category of CKD at 3, 6, 9, and 12 months after lung transplantation (all P<0.001). For all AKI stages, GFR categories worsened with postoperative time. Conclusions: PGD grade was significantly correlated with AKI stage, and AKI stage was correlated with GFR categories of CKD.

Infectious Complications of Lung Transplant for Coronavirus Disease 2019-Associated Lung Injury: A Single-Center Case-Control Cohort Study.

BACKGROUND: Lung transplantation is one of the only options for patients with severe coronavirus disease 2019 (COVID-19)-associated lung injury (CALI). Studies on patients who received a lung transplant for CALI have, to date, not looked at the infectious outcomes. METHODS: After institutional review board approval, a retrospective case-control cohort study, matched 1:1, collected data on patients who underwent lung transplantation for CALI (case) and for non-COVID-19 end-stage lung disease (control) between 1 June 2020 and 1 April 2022 at a large academic hospital in Chicago. We assessed infectious complications and other key outcomes pre-transplant and for 1 year post-transplant. RESULTS: Among 78 patients (39 CALI and 39 matched control lung transplant patients), those in the CALI cohort were less likely to be vaccinated pre-transplant and were more likely to have diabetes, to be obese, to not be ambulatory, and to require pre-transplant extracorporeal membrane oxygenation and mechanical ventilation. Patients transplanted for CALI had higher rates of infection pre-transplant (66.7% vs 15.4% of patients in the control) and in the first 30 days post-transplant (43.6% vs 20.5%). Numbers and types of infection were similar in both groups at other time points. One-year mortality was similar for CALI and control groups (12.8% vs 10.3%, respectively). CONCLUSIONS: Patients who received a lung transplant for CALI are more deconditioned with prolonged hospital stays and experience more infectious complications immediately pre- and post-transplant. Infections due to multidrug-resistant organisms are important contributors to morbidity and mortality in this population. Antimicrobial stewardship is urgently needed.

Clinical Characteristics and Outcomes of Patients With COVID-19-Associated Acute Respiratory Distress Syndrome Who Underwent Lung Transplant.

Importance: Lung transplantation is a potentially lifesaving treatment for patients who are critically ill due to COVID-19-associated acute respiratory distress syndrome (ARDS), but there is limited information about the long-term outcome. Objective: To report the clinical characteristics and outcomes of patients who had COVID-19-associated ARDS and underwent a lung transplant at a single US hospital. Design, Setting, and Participants: Retrospective case series of 102 consecutive patients who underwent a lung transplant at Northwestern University Medical Center in Chicago, Illinois, between January 21, 2020, and September 30, 2021, including 30 patients who had COVID-19-associated ARDS. The date of final follow-up was November 15, 2021. Exposures: Lung transplant. Main Outcomes and Measures: Demographic, clinical, laboratory, and treatment data were collected and analyzed. Outcomes of lung transplant, including postoperative complications, intensive care unit and hospital length of stay, and survival, were recorded. Results: Among the 102 lung transplant recipients, 30 patients (median age, 53 years [range, 27 to 62]; 13 women [43%]) had COVID-19-associated ARDS and 72 patients (median age, 62 years [range, 22 to 74]; 32 women [44%]) had chronic end-stage lung disease without COVID-19. For lung transplant recipients with COVID-19 compared with those without COVID-19, the median lung allocation scores were 85.8 vs 46.7, the median time on the lung transplant waitlist was 11.5 vs 15 days, and preoperative venovenous extracorporeal membrane oxygenation (ECMO) was used in 56.7% vs 1.4%, respectively. During transplant, patients who had COVID-19-associated ARDS received transfusion of a median of 6.5 units of packed red blood cells vs 0 in those without COVID-19, 96.7% vs 62.5% underwent intraoperative venoarterial ECMO, and the median operative time was 8.5 vs 7.4 hours, respectively. Postoperatively, the rates of primary graft dysfunction (grades 1 to 3) within 72 hours were 70% in the COVID-19 cohort vs 20.8% in those without COVID-19, the median time receiving invasive mechanical ventilation was 6.5 vs 2.0 days, the median duration of intensive care unit stay was 18 vs 9 days, the median post-lung transplant hospitalization duration was 28.5 vs 16 days, and 13.3% vs 5.5% required permanent hemodialysis, respectively. None of the lung transplant recipients who had COVID-19-associated ARDS demonstrated antibody-mediated rejection compared with 12.5% in those without COVID-19. At follow-up, all 30 lung transplant recipients who had COVID-19-associated ARDS were alive (median follow-up, 351 days [IQR, 176-555] after transplant) vs 60 patients (83%) who were alive in the non-COVID-19 cohort (median follow-up, 488 days [IQR, 368-570] after lung transplant). Conclusions and Relevance: In this single-center case series of 102 consecutive patients who underwent a lung transplant between January 21, 2020, and September 30, 2021, survival was 100% in the 30 patients who had COVID-19-associated ARDS as of November 15, 2021.

Lung donation following SARS-CoV-2 infection.

There have been over 177 million cases of COVID-19 worldwide, many of whom could be organ donors. Concomitantly, there is an anticipated increase in the need for donor lungs due to expanding indications. Given that the respiratory tract is most commonly affected by COVID-19, there is an urgent need to develop donor assessment criteria while demonstrating safety and "efficacy" of lung donation following COVID-19 infection. Accordingly, we report an intentional transplant using lungs from a donor with recent, microbiologically confirmed, COVID-19 infection into a recipient suffering from COVID-19 induced ARDS and pulmonary fibrosis. In addition to the standard clinical assays, both donor and recipient lungs were analyzed using RNAscope, which confirmed that tissues were negative for SARS-CoV-2. Immunohistochemistry demonstrated colocalized KRT17+ basaloid-like epithelium and COL1A1+ fibroblasts, a marker suggestive of lung fibrosis in COVID-19 associated lung disease, in the explanted recipient lungs but absent in the donor lungs. We demonstrate that following a thorough assessment, lung donation following resolved COVID-19 infection is safe and feasible.

COVID-19 in hospitalized lung and non-lung solid organ transplant recipients: A comparative analysis from a multicenter study.

Lung transplant recipients (LTR) with coronavirus disease 2019 (COVID-19) may have higher mortality than non-lung solid organ transplant recipients (SOTR), but direct comparisons are limited. Risk factors for mortality specifically in LTR have not been explored. We performed a multicenter cohort study of adult SOTR with COVID-19 to compare mortality by 28 days between hospitalized LTR and non-lung SOTR. Multivariable logistic regression models were used to assess comorbidity-adjusted mortality among LTR vs. non-lung SOTR and to determine risk factors for death in LTR. Of 1,616 SOTR with COVID-19, 1,081 (66%) were hospitalized including 120/159 (75%) LTR and 961/1457 (66%) non-lung SOTR (p = .02). Mortality was higher among LTR compared to non-lung SOTR (24% vs. 16%, respectively, p = .032), and lung transplant was independently associated with death after adjusting for age and comorbidities (aOR 1.7, 95% CI 1.0-2.6, p = .04). Among LTR, chronic lung allograft dysfunction (aOR 3.3, 95% CI 1.0-11.3, p = .05) was the only independent risk factor for mortality and age >65 years, heart failure and obesity were not independently associated with death. Among SOTR hospitalized for COVID-19, LTR had higher mortality than non-lung SOTR. In LTR, chronic allograft dysfunction was independently associated with mortality.

Impact of Screening and Treatment of Ureaplasma species on Hyperammonemia Syndrome in Lung Transplant Recipients: A Single Center Experience.

BACKGROUND: Infection with Ureaplasma species (spp) has been linked to fatal hyperammonemia syndrome (HS) in lung transplant recipients. We sought to characterize the epidemiology of Ureaplasma spp in candidates and donors and describe outcomes of antimicrobial therapy in preventing and treating HS. METHODS: Candidate testing for Ureaplasma spp was performed with urine culture and polymerase chain reaction (PCR) pretransplant. Positive candidates were treated with levofloxacin. Donor testing was performed with bronchoalveolar lavage (BAL) culture and PCR intraoperatively. From 7/2014 to 2/2017 patients were treated according to results; from 2/2017 to 10/2018 recipients received empiric levofloxacin and azithromycin at transplant until testing returned negative. HS was defined as new onset altered mental status after transplant with ammonia > 200 µmol/L. RESULTS: In total, 60 patients who underwent lung transplant were included. And 80% (n = 48) of patients had negative screening tests in donor and candidate pre-lung transplant, 8.3% (n = 5) of recipients had positive Ureaplasma spp testing in urine pre-transplant, and 13.3% (n = 8) had positive donor BAL testing at the time of lung transplant. Three patients developed HS a median of 7 days posttransplant; 2 died of HS. Recipients of organs with Ureaplasma spp who received empiric therapy did not develop HS. Donors with Ureaplasma spp were younger and more sexually active. CONCLUSIONS: Donor-derived Ureaplasma spp in lung transplant was associated with HS. Screening lung donors for Ureaplasma spp might allow for targeted therapy to reduce risk for development of HS, but future confirmatory studies are needed.

Lung transplantation for patients with severe COVID-19.

Lung transplantation can potentially be a life-saving treatment for patients with nonresolving COVID-19-associated respiratory failure. Concerns limiting lung transplantation include recurrence of SARS-CoV-2 infection in the allograft, technical challenges imposed by viral-mediated injury to the native lung, and the potential risk for allograft infection by pathogens causing ventilator-associated pneumonia in the native lung. Additionally, the native lung might recover, resulting in long-term outcomes preferable to those of transplant. Here, we report the results of lung transplantation in three patients with nonresolving COVID-19-associated respiratory failure. We performed single-molecule fluorescence in situ hybridization (smFISH) to detect both positive and negative strands of SARS-CoV-2 RNA in explanted lung tissue from the three patients and in additional control lung tissue samples. We conducted extracellular matrix imaging and single-cell RNA sequencing on explanted lung tissue from the three patients who underwent transplantation and on warm postmortem lung biopsies from two patients who had died from COVID-19-associated pneumonia. Lungs from these five patients with prolonged COVID-19 disease were free of SARS-CoV-2 as detected by smFISH, but pathology showed extensive evidence of injury and fibrosis that resembled end-stage pulmonary fibrosis. Using machine learning, we compared single-cell RNA sequencing data from the lungs of patients with late-stage COVID-19 to that from the lungs of patients with pulmonary fibrosis and identified similarities in gene expression across cell lineages. Our findings suggest that some patients with severe COVID-19 develop fibrotic lung disease for which lung transplantation is their only option for survival.

Lung transplantation for pulmonary fibrosis secondary to severe COVID-19.

Lung transplantation can potentially be a life-saving treatment for patients with non-resolving COVID-19 acute respiratory distress syndrome. Concerns limiting transplant include recurrence of SARS-CoV-2 infection in the allograft, technical challenges imposed by viral-mediated injury to the native lung, and potential risk for allograft infection by pathogens associated with ventilator-induced pneumonia in the native lung. Additionally, the native lung might recover, resulting in long-term outcomes preferable to transplant. Here, we report the results of the first two successful lung transplantation procedures in patients with non-resolving COVID-19 associated acute respiratory distress syndrome in the United States. We performed smFISH to detect both positive and negative strands of SARS-CoV-2 RNA in the explanted lung tissue, extracellular matrix imaging using SHIELD tissue clearance, and single cell RNA-Seq on explant and warm post-mortem lung biopsies from patients who died from severe COVID-19 pneumonia. Lungs from patients with prolonged COVID-19 were free of virus but pathology showed extensive evidence of injury and fibrosis which resembled end-stage pulmonary fibrosis. Single cell RNA-Seq of the explanted native lungs from transplant and paired warm post-mortem autopsies showed similarities between late SARS-CoV-2 acute respiratory distress syndrome and irreversible end-stage pulmonary fibrosis requiring lung transplantation. There was no recurrence of SARS-CoV-2 or pathogens associated with pre-transplant ventilator associated pneumonias following transplantation in either patient. Our findings suggest that some patients with severe COVID-19 develop fibrotic lung disease for which lung transplantation is the only option for survival. SINGLE SENTENCE SUMMARY: Some patients with severe COVID-19 develop end-stage pulmonary fibrosis for which lung transplantation may be the only treatment.

Feasibility of Venovenous Extracorporeal Membrane Oxygenation Without Systemic Anticoagulation.

BACKGROUND: Venovenous extracorporeal membrane oxygenation (ECMO) is increasingly being used for acute respiratory distress syndrome and as a bridge to lung transplantation. After initiation of venovenous ECMO, systemic anticoagulation therapy is traditionally administered and can cause bleeding diathesis. Here, we investigated whether venovenous ECMO can be administered without continuous systemic anticoagulation administration for patients with acute respiratory distress syndrome. METHODS: This is a retrospective review of an institutional ECMO database. We included consecutive patients from January 2015 through February 2019. Overall, 38 patients received low levels of continuous systemic anticoagulation (AC+) whereas the subsequent 36 patients received standard venous thromboprophylaxis (AC-). Published Extracorporeal Life Support Organization guidelines were used for the definition of outcomes and complications. RESULTS: Overall, survival was not different between the two groups (P = .58). However, patients in the AC+ group had higher rates of gastrointestinal bleeding (28.9%, vs AC- group 5.6%; P < .001). The events per patient-day of gastrointestinal bleeding was 0.00025 in the AC- group and 0.00064 in the AC+ group (P < .001). In addition, oxygenator dysfunction was increased in the AC+ group (28.9% and 0.00067 events per patient-day, vs AC- 11.1% and 0.00062 events per patient-day; P = .02). Furthermore, the AC+ group received more transfusions: packed red blood cells, AC+ group 94.7% vs AC- group 55.5% (P < .001); fresh frozen plasma, AC+ 60.5% vs AC- 16.6% (P = .001); and platelets, AC+ 84.2% vs AC- 27.7% (P < .001). There was no circuit thrombosis in either groups throughout the duration of ECMO support. CONCLUSIONS: Our results suggest that venovenous ECMO can be safely administered without continuous systemic anticoagulation therapy. This approach may be associated with reduced bleeding diathesis and need for blood transfusions.

Need for tracheostomy after lung transplant predicts decreased mid- and long-term survival.

BACKGROUND: Tracheostomy is an important adjunct for lung transplant patients requiring prolonged ventilation. We explored the effects of post-transplant tracheostomy on survival and bronchiolitis obliterans syndrome after lung transplant. METHODS: A retrospective, single center analysis was performed on all lung transplant recipients during the Lung Allocation Score (LAS) era. Risk factors for post-transplant tracheostomy or death within 30 days were assessed. Kaplan-Meier estimates and Cox proportional hazards models were used to examine the association between tracheostomy within 30 days after transplant and survival at 1 and 3 years. A total of 403 patients underwent single or bilateral lung transplant between May 2005 and February 2016 with complete data for 352 cases, and 35 patients (9.9%) underwent tracheostomy or died (N = 10, 2.8%) within 30 days. RESULTS: In adjusted analyses, primary graft dysfunction grade 3 (PGD3) was associated with a composite end point of tracheostomy or death within 30 days (HR 3.11 (1.69, 5.71), P-value < .001). Tracheostomy within 30 days was associated with decreased survival at 1(HR 4.25 [1.75, 10.35] P-value = .001) and 3 years (HR 2.74 [1.30, 5.76], P-value = .008), as well as decreased bronchiolitis obliterans (BOS)-free survival at 1 (HR 1.87 [1.02, 3.41] P-value = .042) and 3 years (HR 2.15 [1.33, 3.5], P-value = .002). CONCLUSION: Post-transplant tracheostomy is a marker for advanced lung allograft dysfunction with significant reduction in long-term overall and BOS-free survival.

Clinical relevance of lung-restricted antibodies in lung transplantation.

Lung transplant is a definitive treatment for several end-stage lung diseases. However, the high incidence of allograft rejection limits the overall survival following lung transplantation. Traditionally, alloimmunity directed against human leukocyte antigens (HLA) has been implicated in transplant rejection. Recently, the clinical impact of non-HLA lung-restricted antibodies (LRA) has been recognized and extensive research has demonstrated that they may play a dominant role in the development of lung allograft rejection. The immunogenic lung-restricted antigens that have been identified include amongst others, collagen type I, collagen type V, and k-alpha 1 tubulin. Pre-existing antibodies against these lung-restricted antigens are prevalent in patients undergoing lung transplantation and have emerged as one of the predominant risk factors for primary graft dysfunction which limits short-term survival following lung transplantation. Additionally, LRA have been shown to predispose to chronic lung allograft rejection, the predominant cause of poor long-term survival. This review will discuss ongoing research into the mechanisms of development of LRA as well as the pathogenesis of associated lung allograft injury.

Acute exacerbation of interstitial lung disease after procedures.

Interstitial lung disease (ILD) is a category of diffuse parenchymal lung diseases characterized by inflammation and/or fibrosis. The best characterized ILD is idiopathic pulmonary fibrosis (IPF). Acute exacerbation of IPF is a dreaded occurrence with grim prognosis and suboptimal treatment options. There have been recent reports that acute exacerbation can occur in other ILDs (AE-ILD). Of note, some of these acute exacerbations follow lung procedures. This review summarizes the available information on AE-ILD and discusses the procedures reported to cause AE-ILD. We also discuss proposed mechanisms, risk factors, treatment and prognosis. This review should help to inform decision-making about risks versus benefits of procedures that are commonly recommended to diagnose ILD.

Single Versus Bilateral Lung Transplantation for Idiopathic Pulmonary Fibrosis in the Lung Allocation Score Era.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal disease. Lung transplantation is the only therapy associated with prolonged survival. The ideal transplant procedure for IPF is unclear. Outcomes after single transplantation (SLTx) versus bilateral lung transplantation (BLTx) in IPF patients after introduction of the Lung Allocation Score were examined. METHODS: Records of patients undergoing lung transplantation for IPF at our institution between May 2005 and March 2017 were reviewed to examine the effect of transplant laterality. Primary outcomes were overall, rejection-free, and bronchiolitis obliterans (BOS)-free survival at 1 and 5 years post-transplant. RESULTS: Lung transplantation was performed in 151 IPF patients post-Lung Allocation Score. Most recipients were male with average age 59 ± 8 years. SLTx was performed in 94 patients (62%). In the overall cohort, comparative survival between SLTx and BLTx was similar at 1 and 5 years before and after adjusting for age and pulmonary hypertension (PH). SLTx was associated with shorter ventilator time and intensive care unit stay and trended toward improved survival over BLTx in patients without PH. CONCLUSIONS: The use of SLTx versus BLTx in IPF did not correspond to significantly different survival adjusting for age and PH. BLTx was associated with prolonged postoperative ventilation and length of stay compared with SLTx. Patients without PH, all older patients, and patients with PH and advanced disease should be considered for SLTx for IPF.

Patients' perceptions and patient-reported outcomes in progressive-fibrosing interstitial lung diseases.

The effects of interstitial lung disease (ILD) create a significant burden on patients, unsettling almost every domain of their lives, disrupting their physical and emotional well-being and impairing their quality of life (QoL). Because many ILDs are incurable, and there are limited reliably-effective, life-prolonging treatment options available, the focus of many therapeutic interventions has been on improving or maintaining how patients with ILD feel and function, and by extension, their QoL. Such patient-centred outcomes are best assessed by patients themselves through tools that capture their perceptions, which inherently incorporate their values and judgements. These patient-reported outcome measures (PROs) can be used to assess an array of constructs affected by a disease or the interventions implemented to treat it. Here, we review the impact of ILD that may present with a progressive-fibrosing phenotype on patients' lives and examine how PROs have been used to measure that impact and the effectiveness of therapeutic interventions.

Secondary pulmonary arterial hypertension: to treat or not to treat?

PURPOSE OF REVIEW: The purpose of this review is to review recent literature related to mechanisms and treatment options for 'secondary' (i.e., WHO Groups 3 and 5) pulmonary arterial hypertension (PAH). RECENT FINDINGS: Published randomized controlled trials, in general, do not support the use of approved therapies for 'primary' (i.e., WHO Group 1) PAH patients in patients with Group 3 PAH because of the small numbers of patients and inconsistent benefit. Therefore, we currently recommend against the use of these medications for Group 3 PAH. Similarly, there is limited evidence supporting the use of Group 1 PAH medications in Group 5 patients. In most patients with Group 5 PAH, treatment should be directed to the underlying disease. SUMMARY: The utility of PAH-specific therapy in WHO Group 3 PAH is unclear because of the small numbers of patients evaluated and inconsistent beneficial effects observed. There is limited evidence supporting the use of PAH medications in Group 5 patients, and they may be harmful in some cases.

Acute Exacerbation of Interstitial Lung Disease After Cryobiopsy.

Cryotherapy has been used in treatment of lung cancer for decades. The utility of cryotechnology in diagnosis of lung diseases is emerging and gaining popularity. Cryobiopsy (CB) of the lung, when compared with conventional transbronchial forceps lung biopsy, has proposed to have a higher diagnostic yield in interstitial lung disease by providing larger biopsy specimen and less crush artifact. Acute exacerbation of interstitial lung disease (AEILD) has been well described with surgical lung biopsies and, rarely, with conventional transbronchial forceps biopsy. The incidence of AEILD after CB is not known. Here we are presenting a case of AEILD after CB.