COVID-19 in lung transplant recipients: A single center case series from New York City

There are limited data describing COVID-19 in lung transplant recipients. We performed a single center, retrospective case series study of lung transplant patients followed by the Columbia Lung Transplant program who tested positive for SARS-CoV-2 between March 19 and May 19, 2020. Thirty-two lung transplant patients developed mild (16%), moderate (44%), or severe (41%) COVID-19. The median age of patients was 65 years, and the median time from lung transplant was 5.6 years. Symptoms included cough (66%), dyspnea (50%), fever (47%), and gastrointestinal upset (44%). Patients received hydroxychloroquine (84%), azithromycin (75%), augmented steroids (44%), tocilizumab (19%), and remdesivir (9%). Eleven patients (34%) died at a median time of 14 days from admission. Complications during admission included: acute kidney injury (63%), transaminitis (31%), shock (31%), acute respiratory distress syndrome (25%), neurological events (25%), arrhythmias (22%), and venous thromboembolism (9%). Compared to patients with moderate COVID-19, patients with severe COVID-19 had higher peak white blood cell counts (15.8 vs 7 × 10³ /uL, P = .019), C-reactive protein (198 vs. 107 mg/L, P = .010) and D-dimer (8.6 vs. 2.1 ug/mL, P = .004) levels, and lower nadir lymphocyte counts (0.09 vs. 0.4 × 10³ /uL, P = .006). COVID-19 is associated with severe illness and a high mortality rate in lung transplant recipients.

Optical Coherence Tomography of Pulmonary Arterial Walls in Humans and Pigs (Sus scrofa domesticus)

Pulmonary arterial hypertension (PAH) is a devastating disorder characterized by progressive elevation of the pulmonary pressures that, in the absence of therapy, results in chronic right-heart failure and premature death. The vascular pathology of PAH is characterized by progressive loss of small (diameter, less than 50 μm) peripheral pulmonary arteries along with abnormal medial thickening, neointimal formation, and intraluminal narrowing of the remaining pulmonary arteries. Vascular pathology correlates with disease severity, given that hemodynamic effects and disease outcomes are worse in patients with advanced compared with lower-grade lesions. Novel imaging tools are urgently needed that demonstrate the extent of vascular remodeling in PAH patients during diagnosis and treatment monitoring. Optical coherence tomography (OCT) is a catheter-based intravascular imaging technique used to obtain high-resolution 2D and 3D cross-sectional images of coronary arteries, thus revealing the extent of vascular wall pathology due to diseases such as atherosclerosis and in-stent restenosis; its utility as a diagnostic tool in the assessment of the pulmonary circulation is unknown. Here we show that OCT provides high-definition images that capture the morphology of pulmonary arterial walls in explanted human lungs and during pulmonary arterial catheterization of an adult pig. We conclude that OCT may facilitate the evaluation of patients with PAH by disclosing the degree of wall remodeling present in pulmonary vessels. Future studies are warranted to determine whether this information complements the hemodynamic and functional assessments routinely performed in PAH patients, facilitates treatment selection, and improves estimates of prognosis and outcome.

Bloodstream infections in patients with pulmonary arterial hypertension treated with intravenous prostanoids: insights from the REVEAL REGISTRY®

OBJECTIVE

To evaluate the rate of and potential risk factors for bloodstream infections (BSIs) using data from the REVEAL (Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension [PAH] Disease Management) REGISTRY(®), which provides current information about patients with PAH.

PATIENTS AND METHODS

Patients were enrolled from March 30, 2006, through December 8, 2009, and data on reported BSIs were collected through the third quarter of 2010. Bloodstream infection rates were calculated per 1000 patient-days of risk.

RESULTS

Of 3518 patients enrolled, 1146 patients received intravenous (IV) prostanoid therapy for more than 1 day (no BSI, n=1023; ≥1 BSI, n=123; total BSI episodes, n=166). Bloodstream infections rates were significantly increased in patients receiving IV treprostinil vs IV epoprostenol (0.36 vs 0.12 per 1000 treatment days; P<.001), primarily due to gram-negative organisms (0.20 vs 0.03 per 1000 treatment days; P<.001). Multivariate analysis adjusting for age, causes of PAH, and year of BSI found that treatment with IV treprostinil was associated with a 3.08-fold increase (95% confidence interval, 2.05-4.62; P<.001) in BSIs of any type and a 6.86-fold increase (95% confidence interval, 3.60-13.07; P<.001) in gram-negative BSIs compared with treatment with IV epoprostenol.

CONCLUSION

Compared with IV epoprostenol therapy, treatment with IV treprostinil is associated with a significantly higher rate of gram-negative BSIs; observed differences in BSI rate did not seem to be due to any other analyzed factors.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00370214.

Hemodynamic and histologic characterization of a swine (Sus scrofa domestica) model of chronic pulmonary arterial hypertension

The purpose of this work was to develop and characterize an aortopulmonary shunt model of chronic pulmonary hypertension in swine and provide sequential hemodynamic, angiographic, and histologic data by using an experimental endoarterial biopsy catheter. Nine Yucatan female microswine (Sus scrofa domestica) underwent surgical anastomosis of the left pulmonary artery to the descending aorta. Sequential hemodynamic, angiographic, and pulmonary vascular samples were obtained. Six pigs (mean weight, 22.4±5.3 kg; mean age, 7.3±2.7 mo at surgery) survived long-term (6 mo) and consistently developed marked pulmonary arterial hypertension. Angiography showed characteristic central pulmonary arterial enlargement and peripheral tortuosity and pruning. The biopsy catheter was safe and effective in obtaining pulmonary endoarterial samples for histologic studies, which showed neointimal and medial changes. Autopsy confirmed severe pulmonary vascular changes, including concentric obstructive neointimal and plexiform-like lesions. This swine model showed hemodynamic, angiographic, and histologic characteristics of chronic pulmonary arterial hypertension that mimicked the arterial pulmonary hypertension of systemic-to-pulmonary arterial shunts in humans. Experimental data obtained using this and other models and application of an in vivo endoarterial biopsy technique may aid in understanding mechanisms and developing therapies for experimental and human pulmonary arterial hypertension.

Diagnosis and treatment of pulmonary arterial hypertension and atrial fibrillation in an adult chimpanzee (Pan troglodytes)

This report describes the diagnosis and treatment of pulmonary arterial hypertension (PAH) in an adult male captive chimpanzee. Although cardiovascular disease in general is common in human and great apes, diagnosis and treatment of PAH in nonhuman primates are uncommon. In the case we present, the adult chimpanzee was diagnosed with an arrhythmia during an annual physical examination and later with PAH during a scheduled cardiovascular evaluation. PAH can either be primary or secondary and can lead to right ventricular overload and heart failure. This description is the first case study of pulmonary arterial hypertension in a great ape species.