Chronic Thromboembolic Pulmonary Hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH), defined as precapillary pulmonary hypertension (PH) by right heart catheterization and imaging consistent with chronic thromboembolism, is a long-term complication of pulmonary embolism (PE). Pathobiological mechanisms involve pulmonary artery occlusion from organized thromboembolic material despite at least three months of uninterrupted therapeutic anticoagulation following acute PE and secondary microvasculopathy. Delay in diagnosis and management of CTEPH is associated with poor outcomes. High clinical suspicion, comprehensive assessment of residual dyspnea or exercise intolerance in the aftermath of PE and accurate interpretation of computed tomography pulmonary angiography (CTPA) are pivotal steps in the diagnosis. Ventilation-perfusion (V/Q) scan is the preferred initial radiologic screening tool as normal V/Q essentially rules out CTEPH. Any mismatched perfusion defect on the V/Q scan in the setting of PH or any finding compatible with chronic thromboembolism on CTPA should prompt referral to an expert CTEPH center. Once the diagnosis is verified, all eligible patients should be offered pulmonary thromboendarterectomy (PTE). Pulmonary vasodilators or balloon pulmonary angioplasty are safe and effective in inoperable or post-PTE persistent/recurrent CTEPH. During the course of their disease, a patient may receive a combination of treatments, at times consisting of all three strategies. Lifelong therapeutic anticoagulation is recommended for CTEPH.

Identification of a Novel EIF2AK Variant and Genetics-Assisted Approach to Diagnosis of Pulmonary Capillary Hemangiomatosis.

Pulmonary capillary hemangiomatosis (PCH) is an uncommon type of pulmonary vascular disease characterized by capillary proliferation and very poor prognosis owing to misdiagnosis and lack of effective therapeutic options. Mutations in the eukaryotic translation initiation factor 2α kinase 4 (EIF2AK4) gene have been reported in pulmonary veno-occlusive disease and PCH. In this report, we present a patient whose diagnosis of PCH was delayed by 2 ½ years despite prior surgical lung biopsy and clinical and laboratory findings suggestive of pulmonary hypertension. Genotyping revealed a novel likely pathogenic variant in the EIF2AK4 gene. Review of surgical lung biopsy performed 2 ½ years prior confirmed PCH histology along with constrictive bronchiolitis.

Donor derived hepatitis B virus infection: Analysis of the Organ Procurement & Transplantation Network/United Network for Organ Sharing Ad Hoc Disease Transmission Advisory Committee.

Hepatitis B virus (HBV) can be transmitted from organ donor to recipient, but details of transmission events are not widely published. The Disease Transmission Advisory Committee (DTAC) evaluated 105 cases of potential donor derived transmission events of HBV between 2009-2017. Proven, probable or possible transmission of HBV occurred in 25 (23.8%) cases. Recipients of liver grafts were most commonly infected (20 of 21 exposed recipients) compared to 9 of 21 exposed non-hepatic recipients. Eleven of 25 donors were HBV core antibody (HBcAb) positive/HBV surface antigen (HBsAg) negative and infected 8/20 recipients. Of the 10 liver recipients and 1 liver-kidney recipient who received organs from these donors: six were not given antiviral prophylaxis, two developed infection after antiviral prophylaxis was discontinued, two developed HBV while on lamivudine prophylaxis, one was on antiviral prophylaxis and did not develop HBV viremia or antigenemia. One recipient of a HBcAb positive/HBsAg negative kidney developed active HBV infection. Unexpected donor-derived transmission of HBV was a rare event in reports to DTAC, but was often detected in the recipient late post-transplant. Six of 11 recipients (54.5%) of a liver from a HBcAb positive donor did not receive prophylaxis; all of these were potentially preventable with the use of anti-viral prophylaxis.

Ambulatory Transition from Parenteral Prostanoid to Inhaled Treprostinil in Patients with Pulmonary Arterial Hypertension.

PURPOSE: The intravenous or subcutaneous delivery of prostanoid drugs for moderate to severe pulmonary arterial hypertension has been fraught with complications and patient dissatisfaction. Combination therapy including inhaled treprostinil is an attractive alternative in clinically stable patients. Uncertainties exist about the patient characteristics and the optimal setting (inpatient versus office/home) for transition. METHODS: Sixteen stable patients with pulmonary arterial hypertension and favorable risk profile were transitioned from parenteral prostanoid to combination therapy including inhaled treprostinil in the home setting. Nine patients were using intravenous treprostinil, two patients were using subcutaneous treprostinil, and five patients were using intravenous epoprostenol at a median dose of 80 (interquartile range, IQR 72-90), 76.5 (68 and 85), and 28 (IQR 26-30) ng/kg/min respectively. Patients were followed up for a median of 732.5 days after transition (IQR 506.5-1294 days). RESULTS: Patients tolerated the transition to inhaled treprostinil well without significant change in functional class (81.25% FC I/II before transition vs. 87.5% after), 6-min walk distance [349 m (IQR 226-461 m) to 364 m (IQR 238-565 m), p = 0.09] or NT-proBNP [149 pg/ml (IQR 71.5-383 pg/ml) to 186.5 pg/ml (IQR 83.5-444 pg/ml), p = 0.38]. Hemodynamic data, where available, showed significant improvements in mean pulmonary artery pressure and pulmonary vascular resistance from 36 mmHg (IQR 27-46.5 mmHg) and 5.2 Wood Units (WU) (IQR 3.1-5.6 WU) to 28.5 mmHg (IQR 22-35.5 mmHg) and 3.2 WU (IQR 2.4-4.2 WU) (p-values 0.022 and 0.003). More patients were on triple therapy after transition, and side effects reported were less severe. CONCLUSION: For select patients, transition from a parenteral prostanoid-based therapy to a combination regimen including inhaled treprostinil in the home setting appears safe and well tolerated.

Single-Cell Transcriptomic Analysis of Human Lung Provides Insights into the Pathobiology of Pulmonary Fibrosis.

Rationale: The contributions of diverse cell populations in the human lung to pulmonary fibrosis pathogenesis are poorly understood. Single-cell RNA sequencing can reveal changes within individual cell populations during pulmonary fibrosis that are important for disease pathogenesis. Objectives: To determine whether single-cell RNA sequencing can reveal disease-related heterogeneity within alveolar macrophages, epithelial cells, or other cell types in lung tissue from subjects with pulmonary fibrosis compared with control subjects. Methods: We performed single-cell RNA sequencing on lung tissue obtained from eight transplant donors and eight recipients with pulmonary fibrosis and on one bronchoscopic cryobiospy sample from a patient with idiopathic pulmonary fibrosis. We validated these data using in situ RNA hybridization, immunohistochemistry, and bulk RNA-sequencing on flow-sorted cells from 22 additional subjects. Measurements and Main Results: We identified a distinct, novel population of profibrotic alveolar macrophages exclusively in patients with fibrosis. Within epithelial cells, the expression of genes involved in Wnt secretion and response was restricted to nonoverlapping cells. We identified rare cell populations including airway stem cells and senescent cells emerging during pulmonary fibrosis. We developed a web-based tool to explore these data. Conclusions: We generated a single-cell atlas of pulmonary fibrosis. Using this atlas, we demonstrated heterogeneity within alveolar macrophages and epithelial cells from subjects with pulmonary fibrosis. These results support the feasibility of discovery-based approaches using next-generation sequencing technologies to identify signaling pathways for targeting in the development of personalized therapies for patients with pulmonary fibrosis.

Chromoblastomycosis: A Potential Mimic of Squamous Cell Carcinoma in Transplant Recipients.

Chromoblastomycosis (CBM), also known as chromomycosis is a chronic, granulomatous fungal infection of the skin and subcutaneous tissue. It usually occurs by the traumatic inoculation of various dematiaceous fungi and is more common in the developing world. This condition is rare in North America and the developed world. Herein, we present a case of a 75-year-old man who received a bilateral lung transplant 4 months prior and presented for evaluation of a painful, erythematous papule on the elbow which was diagnosed as CBM. This case highlights that immunosuppression used in patients who undergo solid organ transplantation not only increases the risk of opportunistic infections like CBM but can also be confused for cutaneous squamous cell carcinoma as both these entities share many overlapping clinical and histopathologic features and may be a potential source of misdiagnosis.

Long-Term Outcomes of Patients With Pulmonary Embolism Managed With Endovascular Therapies Compared to Medical Therapy.

Background: Guidelines on the management of acute pulmonary embolism (PE) recommend consideration of endovascular therapies (EVT) for patients at intermediate-high risk. However, long-term data on the outcomes of patients after EVT as compared to medical therapy is lacking. This study aimed to compare outcomes of patients receiving EVT as compared to medical therapy alone at 3 to 6 months. Methods: In this single-center, retrospective cohort study, 190 patients with PE underwent evaluation for presence of right ventricular (RV) dysfunction by transthoracic echocardiogram, residual perfusion defects on ventilation-perfusion scanning, and functional capacity by 6-minute walk distance (6MWD) at 3 to 6 month follow-up. Results: Fifty-eight (31%) patients received EVT for the management of their acute PE. At follow-up (median 120 [97-170] days), 71% of patients who received EVT had normalization of RV function compared with only 34% of patients who received medical therapy alone (P < .001). Patients who received EVT had a significantly greater increase in their estimated glomerular filtration rate (P = .001), decrease in N-terminal proB-type natriuretic peptide (P = .003), and decrease in hemoglobin values (P = .018). Patients with intermediate-high to high risk PE who received EVT had significantly greater distance achieved on their 6MWD as compared to those who received medical therapy alone (P = .025). Conclusions: Patients with acute PE who received EVT plus medical therapy were more likely to achieve normalization of RV dysfunction at 3 to 6 month follow-up compared to patients who received medical therapy alone. These data suggest that EVT is an effective therapy option for acute PE in intermediate-high and high risk patients with potential durable long-term benefits.

Telomere length associates with chronological age and mortality across racially diverse pulmonary fibrosis cohorts.

Pulmonary fibrosis (PF) is characterized by profound scarring and poor survival. We investigated the association of leukocyte telomere length (LTL) with chronological age and mortality across racially diverse PF cohorts. LTL measurements among participants with PF stratified by race/ethnicity were assessed in relation to age and all-cause mortality, and compared to controls. Generalized linear models were used to evaluate the age-LTL relationship, Cox proportional hazards models were used for hazard ratio estimation, and the Cochran-Armitage test was used to assess quartiles of LTL. Standardized LTL shortened with increasing chronological age; this association in controls was strengthened in PF (R = -0.28; P < 0.0001). In PF, age- and sex-adjusted LTL below the median consistently predicted worse mortality across all racial groups (White, HR = 2.21, 95% CI = 1.79-2.72; Black, HR = 2.22, 95% CI = 1.05-4.66; Hispanic, HR = 3.40, 95% CI = 1.88-6.14; and Asian, HR = 2.11, 95% CI = 0.55-8.23). LTL associates uniformly with chronological age and is a biomarker predictive of mortality in PF across racial groups.