Sendaway capillary NT-proBNP in pulmonary hypertension.

BACKGROUND: N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a biomarker of cardiac ventricular wall stress that is incorporated into pulmonary hypertension (PH) risk stratification models. Sendaway sampling may enable patients to perform NT-proBNP tests remotely. This UK-wide study aimed to assess the agreement of sendaway NT-proBNP with standard venous NT-proBNP and to assess the effect of delayed processing. METHODS: Reference venous NT-proBNP was collected from PH patients. Samples for capillary and venous sendaway tests were collected contemporaneously, mailed to a reference laboratory and processed at 3 and 7 days using a Roche Cobas e411 device. Differences in paired measurements were analysed with Passing-Bablok regression, percentage difference plots and the % difference in risk strata. RESULTS: 113 patients were included in the study. 13% of day 3 capillary samples were insufficient. Day 3 capillary samples were not equivalent to reference samples (Passing Bablok analysis slope of 0.91 (95% CI 0.88 to 0.93) and intercept of 6.0 (95% CI 0.2 to 15.9)). The relative median difference was -7% and there were acceptable limits of agreement. Day 3 capillary NT-proBNP accurately risk stratified patients in 93.5% of cases. By comparison, day 3 venous results accurately risk stratified patients in 90.1% of cases and were equivalent by Passing-Bablok regression. Delayed sampling of sendaway tests led to an unacceptable level of agreement and systematically underestimated NT-proBNP. CONCLUSIONS: Sendaway NT-proBNP sampling may provide an objective measure of right ventricular strain for virtual PH clinics. Results must be interpreted with caution in cases of delayed sampling.

Blood DNA methylation profiling identifies cathepsin Z dysregulation in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is characterised by pulmonary vascular remodelling causing premature death from right heart failure. Established DNA variants influence PAH risk, but susceptibility from epigenetic changes is unknown. We addressed this through epigenome-wide association study (EWAS), testing 865,848 CpG sites for association with PAH in 429 individuals with PAH and 1226 controls. Three loci, at Cathepsin Z (CTSZ, cg04917472), Conserved oligomeric Golgi complex 6 (COG6, cg27396197), and Zinc Finger Protein 678 (ZNF678, cg03144189), reached epigenome-wide significance (p < 10-7) and are hypermethylated in PAH, including in individuals with PAH at 1-year follow-up. Of 16 established PAH genes, only cg10976975 in BMP10 shows hypermethylation in PAH. Hypermethylation at CTSZ is associated with decreased blood cathepsin Z mRNA levels. Knockdown of CTSZ expression in human pulmonary artery endothelial cells increases caspase-3/7 activity (p < 10-4). DNA methylation profiles are altered in PAH, exemplified by the pulmonary endothelial function modifier CTSZ, encoding protease cathepsin Z.

Pulmonary hypertension in the setting of interstitial lung disease: Approach to management and treatment. A consensus statement from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative-Group 3 Pulmonary Hypertension.

Pulmonary hypertension (PH) due to interstitial lung disease (ILD), a commonly encountered complication of fibrotic ILDs, is associated with significant morbidity and mortality. Until recently, the studies of pulmonary vasodilator therapy in PH-ILD have been largely disappointing, with some even demonstrating the potential for harm. This paper is part of a series of Consensus Statements from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative for Group 3 Pulmonary Hypertension, with prior publications covering pathogenesis, prevalence, clinical features, phenotyping, clinical trials, and impact of PH-ILD. It offers a comprehensive review of and a holistic approach to treatment of PH-ILD, including the management of underlying interstitial lung diseases, importance of treating the comorbidities, emphasis on importance of exercise and palliation of dyspnea, and review of the most up-to-date guidelines for referral for potential lung transplant work up. It also summarizes the prior, ongoing, and possibly future studies in treatment of the vascular derangement of this morbid condition.

Pulmonary hemodynamics and transplant-free survival in sarcoidosis-associated pulmonary hypertension: Results from an international registry.

Pulmonary hypertension (PH) is a risk factor for mortality in patients with sarcoidosis. Severe PH in chronic lung disease has previously been defined as mean pulmonary arterial pressure (mPAP) ≥ 35 mmHg or mPAP 25 ≥ mmHg with cardiac index (CI) ≤ 2 L/min/m2. However, there is no clear definition denoting severity of sarcoidosis-associated PH (SAPH). We aimed to determine pulmonary hemodynamic cut-off values where transplant-free survival was worse among patients with SAPH. This was a retrospective cohort analysis of the Registry of SAPH database focusing on pulmonary hemodynamic predictors of transplant-free survival among patients with precapillary SAPH. Cox regression was performed to determine which pulmonary hemodynamic values predicted death or lung transplantation. Kaplan-Meier survival analysis was performed on statistically significant predictors to determine pulmonary hemodynamic cut-off values where transplant-free survival was decreased. Decreased transplant-free survival occurred among SAPH patients with mPAP ≥ 40 mmHg and SAPH patients with pulmonary vascular resistance (PVR) ≥ 5 Woods units (WU). Transplant-free survival was not decreased in patients who fulfilled prior criteria of severe PH in chronic lung disease. We identified new cut-offs with decreased transplant-free survival in the SAPH population. Neither cut-off of mPAP ≥ 40 mmHg nor PVR ≥ 5 WU has previously been shown to be associated with decreased transplant-free survival in SAPH. These values could suggest a new definition of severe SAPH. Our PVR findings are in line with the most recent European Society of Cardiology/European Respiratory Society guideline definition of severe PH in chronic lung disease.

Phosphodiesterase 5 inhibitor treatment and survival in interstitial lung disease pulmonary hypertension: A Bayesian retrospective observational cohort study.

BACKGROUND AND OBJECTIVE: Pulmonary hypertension is a life-limiting complication of interstitial lung disease (ILD-PH). We investigated whether treatment with phosphodiesterase 5 inhibitors (PDE5i) in patients with ILD-PH was associated with improved survival. METHODS: Consecutive incident patients with ILD-PH and right heart catheterisation, echocardiography and spirometry data were followed from diagnosis to death, transplantation or censoring with all follow-up and survival data modelled by Bayesian methods. RESULTS: The diagnoses in 128 patients were idiopathic pulmonary fibrosis (n = 74, 58%), hypersensitivity pneumonitis (n = 17, 13%), non-specific interstitial pneumonia (n = 12, 9%), undifferentiated ILD (n = 8, 6%) and other lung diseases (n = 17, 13%). Final outcomes were death (n = 106, 83%), transplantation (n = 9, 7%) and censoring (n = 13, 10%). Patients treated with PDE5i (n = 50, 39%) had higher mean pulmonary artery pressure (median 38 mm Hg [interquartile range, IQR: 34, 43] vs. 35 mm Hg [IQR: 31, 38], p = 0.07) and percentage predicted forced vital capacity (FVC; median 57% [IQR: 51, 73] vs. 52% [IQR: 45, 66], p=0.08) though differences did not reach significance. Patients treated with PDE5i survived longer than untreated patients (median 2.18 years [95% CI: 1.43, 3.04] vs. 0.94 years [0.69, 1.51], p = 0.003) independent of all other prognostic markers by Bayesian joint-modelling (HR 0.39, 95% CI: 0.23, 0.59, p < 0.001) and propensity-matched analyses (HR 0.38, 95% CI: 0.22, 0.58, p < 0.001). Survival difference with treatment was significantly larger if right ventricular function was normal, rather than abnormal, at presentation (+2.55 years, 95% CI: -0.03, +3.97 vs. +0.98 years, 95% CI: +0.47, +2.00, p = 0.04). CONCLUSION: PDE5i treatment in ILD-PH should be investigated by a prospective randomized trial.

Clinical significance of pulmonary hypertension in interstitial lung disease: A consensus statement from the Pulmonary Vascular Research Institute's innovative drug development initiative-Group 3 pulmonary hypertension.

Pulmonary hypertension (PH) has been linked to worse outcomes in chronic lung diseases. The presence of PH in the setting of underlying Interstitial Lung Disease (ILD) is strongly associated with decreased exercise and functional capacity, an increased risk of hospitalizations and death. Examining the scope of this issue and its impact on patients is the first step in trying to define a roadmap to facilitate and encourage future research in this area. The aim of our working group is to strengthen the communities understanding of PH due to lung diseases and to improve the care and quality of life of affected patients. This introductory statement provides a broad overview and lays the foundation for further in-depth papers on specific topics pertaining to PH-ILD.

First Genotype-Phenotype Study in TBX4 Syndrome: Gain-of-Function Mutations Causative for Lung Disease.

Rationale: Despite the increased recognition of TBX4 (T-BOX transcription factor 4)-associated pulmonary arterial hypertension (PAH), genotype-phenotype associations are lacking and may provide important insights. Objectives: To compile and functionally characterize all TBX4 variants reported to date and undertake a comprehensive genotype-phenotype analysis. Methods: We assembled a multicenter cohort of 137 patients harboring monoallelic TBX4 variants and assessed the pathogenicity of missense variation (n = 42) using a novel luciferase reporter assay containing T-BOX binding motifs. We sought genotype-phenotype correlations and undertook a comparative analysis with patients with PAH with BMPR2 (Bone Morphogenetic Protein Receptor type 2) causal variants (n = 162) or no identified variants in PAH-associated genes (n = 741) genotyped via the National Institute for Health Research BioResource-Rare Diseases. Measurements and Main Results: Functional assessment of TBX4 missense variants led to the novel finding of gain-of-function effects associated with older age at diagnosis of lung disease compared with loss-of-function effects (P = 0.038). Variants located in the T-BOX and nuclear localization domains were associated with earlier presentation (P = 0.005) and increased incidence of interstitial lung disease (P = 0.003). Event-free survival (death or transplantation) was shorter in the T-BOX group (P = 0.022), although age had a significant effect in the hazard model (P = 0.0461). Carriers of TBX4 variants were diagnosed at a younger age (P < 0.001) and had worse baseline lung function (FEV1, FVC) (P = 0.009) than the BMPR2 and no identified causal variant groups. Conclusions: We demonstrated that TBX4 syndrome is not strictly the result of haploinsufficiency but can also be caused by gain of function. The pleiotropic effects of TBX4 in lung disease may be in part explained by the differential effect of pathogenic mutations located in critical protein domains.

A framework of deep learning networks provides expert-level accuracy for the detection and prognostication of pulmonary arterial hypertension.

AIMS: To test the hypothesis that deep learning (DL) networks reliably detect pulmonary arterial hypertension (PAH) and provide prognostic information. METHODS AND RESULTS: Consecutive patients with PAH, right ventricular (RV) dilation (without PAH), and normal controls were included. An ensemble of deep convolutional networks incorporating echocardiographic views and estimated RV systolic pressure (RVSP) was trained to detect (invasively confirmed) PAH. In addition, DL-networks were trained to segment cardiac chambers and extracted geometric information throughout the cardiac cycle. The ability of DL parameters to predict all-cause mortality was assessed using Cox-proportional hazard analyses. Overall, 450 PAH patients, 308 patients with RV dilatation (201 with tetralogy of Fallot and 107 with atrial septal defects) and 67 normal controls were included. The DL algorithm achieved an accuracy and sensitivity of detecting PAH on a per patient basis of 97.6 and 100%, respectively. On univariable analysis, automatically determined right atrial area, RV area, RV fractional area change, RV inflow diameter and left ventricular eccentricity index (P < 0.001 for all) were significantly related to mortality. On multivariable analysis DL-based RV fractional area change (P < 0.001) and right atrial area (P = 0.003) emerged as independent predictors of outcome. Statistically, DL parameters were non-inferior to measures obtained manually by expert echocardiographers in predicting prognosis. CONCLUSION: The study highlights the utility of DL algorithms in detecting PAH on routine echocardiograms irrespective of RV dilatation. The algorithms outperform conventional echocardiographic evaluation and provide prognostic information at expert-level. Therefore, DL methods may allow for improved screening and optimized management of PAH.

Using the Plasma Proteome for Risk Stratifying Patients with Pulmonary Arterial Hypertension.

Rationale: NT-proBNP (N-terminal pro-brain natriuretic peptide), a biomarker of cardiac origin, is used to risk stratify patients with pulmonary arterial hypertension (PAH). Its limitations include poor sensitivity to early vascular pathology. Other biomarkers of vascular or systemic origin may also be useful in the management of PAH. Objectives: Identify prognostic proteins in PAH that complement NT-proBNP and clinical risk scores. Methods: An aptamer-based assay (SomaScan version 4) targeting 4,152 proteins was used to measure plasma proteins in patients with idiopathic, heritable, or drug-induced PAH from the UK National Cohort of PAH (n = 357) and the French EFORT (Evaluation of Prognostic Factors and Therapeutic Targets in PAH) study (n = 79). Prognostic proteins were identified in discovery-replication analyses of UK samples. Proteins independent of 6-minute-walk distance and NT-proBNP entered least absolute shrinkage and selection operator modeling, and the best combination in a single score was evaluated against clinical targets in EFORT. Measurements and Main Results: Thirty-one proteins robustly informed prognosis independent of NT-proBNP and 6-minute-walk distance in the UK cohort. A weighted combination score of six proteins was validated at baseline (5-yr mortality; area under the curve [AUC], 0.73; 95% confidence interval [CI], 0.63-0.85) and follow-up in EFORT (AUC, 0.84; 95% CI, 0.75-0.94; P = 9.96 × 10-6). The protein score risk stratified patients independent of established clinical targets and risk equations. The addition of the six-protein model score to NT-proBNP improved prediction of 5-year outcomes from AUC 0.762 (0.702-0.821) to 0.818 (0.767-0.869) by receiver operating characteristic analysis (P = 0.00426 for difference in AUC) in the UK replication and French samples combined. Conclusions: The plasma proteome informs prognosis beyond established factors in PAH and may provide a more sensitive measure of therapeutic response.

Positioning imatinib for pulmonary arterial hypertension: A phase I/II design comprising dose finding and single-arm efficacy.

Pulmonary arterial hypertension is an unmet clinical need. Imatinib, a tyrosine kinase inhibitor, 200 to 400 mg daily reduces pulmonary artery pressure and increases functional capacity in this patient group, but is generally poorly tolerated at the higher dose. We have designed an open-label, single-arm clinical study to investigate whether there is a tolerated dose of imatinib that can be better targeted to patients who will benefit. The study consists of two parts. Part 1 seeks to identify the best tolerated dose of Imatinib in the range from 100 and up to 400 mg using a Bayesian Continuous Reassessment Method. Part 2 will measure efficacy after 24 weeks treatment with the best tolerated dose using a Simon's two-stage design. The primary efficacy endpoint is a binary variable. For patients with a baseline pulmonary vascular resistance (PVR) >1000 dynes · s · cm-5, success is defined by an absolute reduction in PVR of ≥300 dynes · s · cm-5 at 24 weeks. For patients with a baseline PVR ≤1000 dynes · s · cm-5, success is a 30% reduction in PVR at 24 weeks. PVR will also be evaluated as a continuous variable by genotype as an exploratory analysis. Evaluating the response to that dose by genotype may inform a prospective biomarker-driven study.

Impact of cyanosis on ventilatory responses during stair climb exercise in Eisenmenger syndrome and idiopathic pulmonary arterial hypertension.

Studies assessing exercise ventilatory responses during real-life exercise in pulmonary arterial hypertension (PAH) which include patients with cyanotic congenital heart disease are scarce. We assessed the ventilatory response to stairclimbing in patients with idiopathic PAH (IPAH) and congenital heart disease-associated PAH with Eisenmenger (EIS) physiology compared to healthy controls. Fifteen adults with IPAH, six EIS and 15 age and body mass index (BMI) matched controls were prospectively recruited. Participants completed spirometry and a self-paced stair-climb (48 steps) with portable cardiopulmonary exercise testing (CPET) equipment in-situ. Borg dyspnoea scores were measured at rest and on stair-climb cessation. Both IPAH and EIS groups had amplified ventilatory responses compared to Controls. The rate of increase in minute ventilation (VE) was exaggerated in EIS driven by an early increase in tidal volume (Tv) and more gradual increase in respiratory rate (RR). Peak Tv, RR, Tv: forced vital capacity (FVC) ratio, VE/VCO2 slope and stairclimb duration were significantly higher in EIS and IPAH compared to controls despite similar baseline spirometry and change in oxygen uptake on exercise. A decline in end-tidal carbon dioxide (CO2) and arterial oxygen saturations in early exercise distinguished EIS and IPAH patients. Significant correlations were observed between peak exercise Borg score and stair-climb time (r = 0.73, p = 0.002), peak end-tidal CO2 (r = -0.73, p = 0.001), peak VE (r = 0.53, p = 0.008), peak RR (r = 0.42, p = 0.011) and VE/VCO2 slope (r = 0.54, p = 0.001). Patients with IPAH and EIS have exaggerated ventilatory responses to stair-climbing compared to the controls with more severe levels of dyspnoea perception in Eisenmenger syndrome for equivalent oxygen uptake and work.

Neurological complications in aortic coarctation: Results of a Nationwide analysis based on 11,907 patients.

BACKGROUND: Patients with coarctation of the aorta (CoA) are at increased risk of periprocedural and late neurological complications. Based on a nationwide inpatient dataset, we assessed the prevalence and risk factors for neurological complications in this cohort. METHOD AND RESULTS: We included all CoA patients hospitalized in England between 1997 and 2015. The risk for procedural complications, subarachnoid bleeding and ischemic stroke were quantified, and risk factors investigated. Overall, 11,907 patients (60% male) with CoA were identified. The median age at first presentation was 0.6 years with a median follow-up period of 14.4 years. Throughout the study period, 8456 surgical or interventional procedures were performed in 6796 patients. The neurological complication rate for primary surgical or interventional repair in patients born after 1997 was 0.05% and 0.2%, respectively. During a total follow-up period of 146,295 patient-years, late neurological complications such as subarachnoid bleeding and cerebral infarction occurred in 225 patients (0.15%/patient-year). The median age for subarachnoid bleeding was 29 years and 57 years for ischemic stroke. While, arterial hypertension (p = .0014), current smoking (p = .02), dyslipidaemia (p = .007) and diabetes (p = .037) were significantly related to the risk of ischemic stroke, only arterial hypertension emerged as significant risk factor for subarachnoid bleeding. CONCLUSIONS: Neurological complication during primary CoA repair are extremely rare in the current era. In contrast, many CoA patients are afflicted by late complications such as subarachnoid bleeding and ischemic stroke at a relatively young age, emphasizing the need for meticulous and pro-active blood pressure control and reduction of cardiovascular risk factors.

Endothelial protective factors BMP9 and BMP10 inhibit CCL2 release by human vascular endothelial cells.

Bone morphogenetic protein 9 (BMP9) and BMP10 are circulating ligands that mediate endothelial cell (EC) protection via complexes of the type I receptor ALK1 and the type II receptors activin type-IIA receptor (ACTR-IIA) and bone morphogenetic type II receptor (BMPR-II). We previously demonstrated that BMP9 induces the expression of interleukin-6, interleukin-8 and E-selectin in ECs and might influence their interactions with monocytes and neutrophils. We asked whether BMP9 and BMP10 regulate the expression of chemokine (C-C motif) ligand 2 (CCL2), a key chemokine involved in monocyte-macrophage chemoattraction. Here, we show that BMP9 and BMP10 repress basal CCL2 expression and release from human pulmonary artery ECs and aortic ECs. The repression was dependent on ALK1 and co-dependent on ACTR-IIA and BMPR-II. Assessment of canonical Smad signalling indicated a reliance of this response on Smad4. Of note, Smad1/5 signalling contributed only at BMP9 concentrations similar to those in the circulation. In the context of inflammation, BMP9 did not alter the induction of CCL2 by TNF-α. As CCL2 promotes monocyte/macrophage chemotaxis and endothelial permeability, these data support the concept that BMP9 preserves basal endothelial integrity.

Whole-Blood RNA Profiles Associated with Pulmonary Arterial Hypertension and Clinical Outcome.

Rationale: Idiopathic and heritable pulmonary arterial hypertension (PAH) are rare but comprise a genetically heterogeneous patient group. RNA sequencing linked to the underlying genetic architecture can be used to better understand the underlying pathology by identifying key signaling pathways and stratify patients more robustly according to clinical risk.Objectives: To use a three-stage design of RNA discovery, RNA validation and model construction, and model validation to define a set of PAH-associated RNAs and a single summarizing RNA model score. To define genes most likely to be involved in disease development, we performed Mendelian randomization (MR) analysis.Methods: RNA sequencing was performed on whole-blood samples from 359 patients with idiopathic, heritable, and drug-induced PAH and 72 age- and sex-matched healthy volunteers. The score was evaluated against disease severity markers including survival analysis using all-cause mortality from diagnosis. MR used known expression quantitative trait loci and summary statistics from a PAH genome-wide association study.Measurements and Main Results: We identified 507 genes with differential RNA expression in patients with PAH compared with control subjects. A model of 25 RNAs distinguished PAH with 87% accuracy (area under the curve 95% confidence interval: 0.791-0.945) in model validation. The RNA model score was associated with disease severity and long-term survival (P = 4.66 × 10-6) in PAH. MR detected an association between SMAD5 levels and PAH disease susceptibility (odds ratio, 0.317; 95% confidence interval, 0.129-0.776; P = 0.012).Conclusions: A whole-blood RNA signature of PAH, which includes RNAs relevant to disease pathogenesis, associates with disease severity and identifies patients with poor clinical outcomes. Genetic variants associated with lower SMAD5 expression may increase susceptibility to PAH.

miR-1-5p targets TGF-ßR1 and is suppressed in the hypertrophying hearts of rats with pulmonary arterial hypertension.

The microRNA miR-1 is an important regulator of muscle phenotype including cardiac muscle. Down-regulation of miR-1 has been shown to occur in left ventricular hypertrophy but its contribution to right ventricular hypertrophy in pulmonary arterial hypertension are not known. Previous studies have suggested that miR-1 may suppress transforming growth factor-beta (TGF-ß) signalling, an important pro-hypertrophic pathway but only indirect mechanisms of regulation have been identified. We identified the TGF-ß type 1 receptor (TGF-ßR1) as a putative miR-1 target. We therefore hypothesized that miR-1 and TGF-ßR1 expression would be inversely correlated in hypertrophying right ventricle of rats with pulmonary arterial hypertension and that miR-1 would inhibit TGF-ß signalling by targeting TGF-ßR1 expression. Quantification of miR-1 and TGF-ßR1 in rats treated with monocrotaline to induce pulmonary arterial hypertension showed appropriate changes in miR-1 and TGF-ßR1 expression in the hypertrophying right ventricle. A miR-1-mimic reduced enhanced green fluorescent protein expression from a reporter vector containing the TGF-ßR1 3'- untranslated region and knocked down endogenous TGF-ßR1. Lastly, miR-1 reduced TGF-ß activation of a (mothers against decapentaplegic homolog) SMAD2/3-dependent reporter. Taken together, these data suggest that miR-1 targets TGF-ßR1 and reduces TGF-ß signalling, so a reduction in miR-1 expression may increase TGF-ß signalling and contribute to cardiac hypertrophy.

A single-centre, placebo-controlled, double-blind randomised cross-over study of nebulised iloprost in patients with Eisenmenger syndrome: A pilot study.

BACKGROUND: Pulmonary arterial hypertension (PAH), is a rare and progressive disease with a high morbidity and mortality. Prostanoid pulmonary vasodilators are the most effective treatment for idiopathic and connective tissue associated PAH. Nonetheless, data examining their safety and efficacy in patients with Eisenmenger syndrome the most severe form of PAH, that is, related to cyanotic congenital heart disease (CHD-PAH) remains limited. AIM: To evaluate safety and the clinical efficacy of nebulised iloprost in patients with Eisenmenger syndrome who are on maximum background oral PAH therapy. METHODS: This pilot study was a randomised, double-blind, placebo-controlled, cross-over study. Patients were randomised to receive nebulised placebo or iloprost for 12 weeks and were then crossed over, with a 7-14-day washout. The primary endpoint was a change in 6-minute walk distance (6MWD). RESULTS: Sixteen patients (11 females, aged 47.3 ±â€¯9.8 year) were recruited, twelve completed the study. All were in WHO-FC III, with a resting oxygen saturation of 84 [81-87] % and a median 6MWD of 290 [260-300] m. There was no significant difference in the primary endpoint between nebulised iloprost (0[-4-9]m) and placebo (10 [-15-51]m), p = 0.58. There were no safety concerns with nebulised iloprost. CONCLUSIONS: Our pilot study provides preliminary evidence that the addition of nebulised iloprost to maximum oral PAH therapy did not improve the primary endpoint of 6MWD. Nebulised iloprost was well tolerated with no significant safety concerns in CHD-PAH.

Rescue therapy with thrombolysis in patients with severe COVID-19-associated acute respiratory distress syndrome.

Acute respiratory distress syndrome in patients with Coronavirus disease 19 is associated with an unusually high incidence of pulmonary embolism and microthrombotic disease, with evidence for reduced fibrinolysis. We describe seven patients requiring invasive ventilation for COVID-19-associated acute respiratory distress syndrome with pulmonary thromboembolic disease, pulmonary hypertension ± severe right ventricular dysfunction on echocardiography, who were treated with alteplase as fibrinolytic therapy. All patients were non-smokers, six (86%) were male and median age was 56.7 (50-64) years. They had failed approaches including therapeutic anticoagulation, prone ventilation (n = 4), inhaled nitric oxide (n = 5) and nebulised epoprostenol (n = 2). The median duration of mechanical ventilation prior to thrombolysis was seven (5-11) days. Systemic alteplase was administered to six patients (50 mg or 90 mg bolus over 120 min) at 16 (10-22) days after symptom onset. All received therapeutic heparin pre- and post-thrombolysis, without intracranial haemorrhage or other major bleeding. Alteplase improved PaO2/FiO2 ratio (from 97.0 (86.3-118.6) to 135.6 (100.7-171.4), p = 0.03) and ventilatory ratio (from 2.76 (2.09-3.49) to 2.36 (1.82-3.05), p = 0.011) at 24 h. Echocardiographic parameters at two (1-3) days (n = 6) showed right ventricular systolic pressure (RVSP) was 63 (50.3-75) then 57 (49-66) mmHg post-thrombolysis (p = 0.26), tricuspid annular planar systolic excursion (TAPSE) was unchanged (from 18.3 (11.9-24.5) to 20.5 (15.4-24.2) mm, p = 0.56) and right ventricular fractional area change (from 15.4 (11.1-35.6) to 31.2 (16.4-33.1)%, p = 0.09). At seven (1-13) days after thrombolysis, using dual energy computed tomography imaging (n = 3), average relative peripheral lung enhancement increased from 12.6 to 21.6% (p = 0.06). In conclusion, thrombolysis improved PaO2/FiO2 ratio and ventilatory ratio at 24 h as rescue therapy in patients with right ventricular dysfunction due to COVID-19-associated ARDS despite maximum therapy, as part of a multimodal approach, and warrants further study.