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BACKGROUND: Most lung cancers are diagnosed at an advanced stage and therefore have a poor prognosis. One major challenge is to choose the most adapted sampling technique to obtain a rapid pathological diagnosis so as to start treatment as early as possible. A growing number of techniques have been developed in recent years. This study sought to assess the diagnostic efficiency of each, along with the respective duration of the diagnostic pathways. METHODS: This retrospective, bicentric, observational study enrolled patients with inoperable lung cancer (stage III or IV) diagnosed in 2018-2019. Diagnostic efficiency was assessed based on the different examinations performed to achieve a precise diagnosis (pathology, immunohistochemistry, and/or molecular biology). The time between the first medical contact and treatment initiation was also assessed. RESULTS: Overall, 625 patients were included (median age 67 years; men 67 %; adenocarcinoma 55 %). The most frequent examinations were bronchial endoscopy (n = 469, 75 %), followed by metastasis biopsy (n = 137, 21.9 %) and guided transthoracic core-needle biopsy (TCNB) (n = 116, 18.6 %). 372 patients had only one procedure (59.5 %), mainly bronchial endoscopy (n = 217, 34.7 %) and metastasis biopsy (n = 71, 11 %). The most efficient examination was thoracic surgery (surgical pleural biopsy, (n = 32, 100 %); mediastinoscopy (n = 26, 96.3 %); surgical pulmonary biopsy (n = 14, 93.3 %). The second most efficient examination was metastasis biopsy (n = 126, 94 %) followed by guided TCNB (n = 108, 93.1 %). The median time from first medical contact to first examination was 4 days (interquartile range 25 %-75 % 1-8). The median time from first medical contact to pathological result was 17 days (10-34). The median time from first medical contact to treatment start was 48 days (30-69). CONCLUSIONS: In order to make an accurate and rapid diagnosis of lung cancer, it is crucial to choose the most appropriate technique. Bronchial endoscopy remains the first-line examination for central lesions, as it is efficient and easily accessible. Guided TCNB and metastasis biopsy are the preferred techniques for peripheral lesions. The choice of the diagnostic technique should be part of a multidisciplinary approach and a dedicated pathway to optimize initial management.
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In patients with very severe CTEPH eligible for BPA, it is possible to achieve major haemodynamic improvement with upfront triple PH therapy including epoprostenol and then to perform angioplasties https://bit.ly/3vZZvib.
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BACKGROUND: Forced vital capacity (FVC) is routinely used to quantify the severity and identify the progression of idiopathic pulmonary fibrosis (IPF). Although less commonly used, lung transfer of carbon monoxide (TLCO) correlates better with the severity of IPF than does FVC. METHODS: Aiming at studying how FVC behaves in relation to TLCO, we analysed cross-sectional data from 430 IPF patients, of which 221 had at least 2 assessments (performed 2.4 ± 1.9 years apart) available for longitudinal analyses. Thresholds for identifying "abnormal" FVC and TLCO values were the statistically-defined lower limits of normal (LLN). For patients with longitudinal data, mean annual absolute declines of FVC and TLCO were calculated. RESULTS: The correlation between FVC and TLCO (%predicted) was weak (R2=0.21). FVC was "abnormal" (i.e., Subject(s)
Carbon Monoxide
, Idiopathic Pulmonary Fibrosis
, Humans
, Cross-Sectional Studies
, Lung
, Vital Capacity
, Idiopathic Pulmonary Fibrosis/diagnosis
ABSTRACT
OBJECTIVES: COVID-19 pandemic seems to be under control. However, despite the vaccines, 5 to 10% of the patients with mild disease develop moderate to critical forms with potential lethal evolution. In addition to assess lung infection spread, chest CT helps to detect complications. Developing a prediction model to identify at-risk patients of worsening from mild COVID-19 combining simple clinical and biological parameters with qualitative or quantitative data using CT would be relevant to organizing optimal patient management. METHODS: Four French hospitals were used for model training and internal validation. External validation was conducted in two independent hospitals. We used easy-to-obtain clinical (age, gender, smoking, symptoms' onset, cardiovascular comorbidities, diabetes, chronic respiratory diseases, immunosuppression) and biological parameters (lymphocytes, CRP) with qualitative or quantitative data (including radiomics) from the initial CT in mild COVID-19 patients. RESULTS: Qualitative CT scan with clinical and biological parameters can predict which patients with an initial mild presentation would develop a moderate to critical form of COVID-19, with a c-index of 0.70 (95% CI 0.63; 0.77). CT scan quantification improved the performance of the prediction up to 0.73 (95% CI 0.67; 0.79) and radiomics up to 0.77 (95% CI 0.71; 0.83). Results were similar in both validation cohorts, considering CT scans with or without injection. CONCLUSION: Adding CT scan quantification or radiomics to simple clinical and biological parameters can better predict which patients with an initial mild COVID-19 would worsen than qualitative analyses alone. This tool could help to the fair use of healthcare resources and to screen patients for potential new drugs to prevent a pejorative evolution of COVID-19. CLINICAL TRIAL REGISTRATION: NCT04481620. CLINICAL RELEVANCE STATEMENT: CT scan quantification or radiomics analysis is superior to qualitative analysis, when used with simple clinical and biological parameters, to determine which patients with an initial mild presentation of COVID-19 would worsen to a moderate to critical form. KEY POINTS: ⢠Qualitative CT scan analyses with simple clinical and biological parameters can predict which patients with an initial mild COVID-19 and respiratory symptoms would worsen with a c-index of 0.70. ⢠Adding CT scan quantification improves the performance of the clinical prediction model to an AUC of 0.73. ⢠Radiomics analyses slightly improve the performance of the model to a c-index of 0.77.
Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Pandemics , Models, Statistical , Prognosis , Retrospective StudiesABSTRACT
BACKGROUND: The identification of the first ventilatory threshold (VT1) on an incremental cardiopulmonary exercise test (CPET) is useful to guide exercise reconditioning. However, determination of the VT1 is sometimes difficult in patients with chronic respiratory disease. Our hypothesis was that it would be possible to identify a "clinical threshold" based on patients' perceptions at which they subjectively consider that they can perform endurance training during a rehabilitation programme. METHODS: Workloads at which patients identified a "clinical threshold" during a submaximal exercise were compared with workloads recorded at VT1 determined during a maximal CPET. Patients with a VT1 and/or a "clinical threshold" obtained at a workload <25 W were excluded from the analysis. RESULTS: A "clinical threshold" could be determined in the 86 patients included. Data from 63 patients were retained for the analysis, of which only 52 had a VT1 that could be identified. The agreement between the workloads determined at VT1 and at the "clinical threshold" was almost perfect, with a Lin's concordance coefficient (cc) of 0.82. CONCLUSIONS: In the context of chronic respiratory diseases, it is possible to use patients' sensations (which are by nature subjective) to identify a workload on a cycle ergometer, which corresponds to the workload at the first ventilatory threshold determined objectively during CPET.
Subject(s)
Exercise Test , Respiratory Tract Diseases , Humans , Feasibility Studies , Exercise , ErgometryABSTRACT
The rheology of sputum is viewed as a powerful emerging biophysical marker for monitoring muco-obstructive pulmonary diseases such as cystic fibrosis (CF) and non-CF bronchiectasis (NCFB). However, there is no unified practice to process sputa from collection to analysis, which can lead to highly variable, and sometimes inconsistent results. The main objective of this study is to bring light into the handling of sputum samples to establish a standardised and robust protocol before rheological measurements. Sputum collected from 22 CF and 10 NCFB adults, was divided into control (vortexed and fresh: non-heated and non-frozen) and three treated conditions (either non-vortexed, heated or frozen). In addition, 6 CF expectorations were used to study the dynamics of ageing over 24 h. Sputum's mechanical properties were measured with a rotational rheometer to obtain their properties at rest, elastic ([Formula: see text]) and viscous moduli ([Formula: see text]), and at the onset of flow, critical deformation ([Formula: see text]) and critical stress ([Formula: see text]). We demonstrate that heating sputum is completely destructive while freezing sputa at [Formula: see text] has no discernible effect on their rheology. We also show that the variability of rheological measurements largely resulted from the sample's macroscopic heterogeneity, and can be greatly reduced by non-destructive vortex homogenisation. Finally, we observed contrasted ageing effects as a fonction of purulence: while the viscoelasticity of purulent samples reduced by half within 6 h after collection, semi-purulent samples did not evolve. These results guide towards a robust unified protocol for simple sputum handling in rheometry. We therefore suggest to vortex and snap freeze sputum samples immediately after collection when direct testing is not possible.
Subject(s)
Bronchiectasis , Cystic Fibrosis , Lung Diseases, Obstructive , Adult , Humans , Sputum , Rheology/methodsABSTRACT
Objective: To determine whether changes in pulmonary vascular resistance (PVR) and changes in pulmonary artery compliance (C pa) are associated with changes in exercise capacity assessed either by changes in peak oxygen consumption (V'O2 ) or by changes in 6-min walk distance (6MWD) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) undergoing balloon pulmonary angioplasty (BPA). Methods: Invasive haemodynamic parameters, peak V'O2 and 6MWD were measured within 24â h, before and after BPA (interval 3.1±2.4â months) in 34 CTEPH patients without significant cardiac and/or pulmonary comorbidities, of whom 24 received at least one pulmonary hypertension-specific treatment. C pa was calculated according to the pulse pressure method: C pa=((SV/PP)/1.76+0.1), where SV is the stroke volume and PP is the pulse pressure. The resistance-compliance (RC)-time of the pulmonary circulation was calculated as the PVR and C pa product. Results: After BPA, PVR decreased (562±234 versus 290±106â dyn·s·cm-5; p<0.001); C pa increased (0.90±0.36 versus 1.63±0.65â mL·mmHg-1; p<0.001); but RC-time did not change (0.325±0.069 versus 0.321±0.083â s; p=0.75). There were improvements in peak V'O2 (1.11±0.35 versus 1.30±0.33â L·min-1; p<0.001) and in 6MWD (393±119 versus 432±100â m; p<0.001). After adjustment for age, height, weight and gender, changes in exercise capacity, assessed either by peak V'O2 or 6MWD, were significantly associated with changes in PVR, but not with changes in C pa. Conclusions: Contrary to what has been reported in CTEPH patients undergoing pulmonary endarterectomy, in CTEPH patients undergoing BPA, changes in exercise capacity were not associated with changes in C pa.
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Nocardiosis is a disease that mainly affects immunocompromised patients. Inhaled corticosteroids (ICS) are standard of care for asthma. This treatment can induce respiratory infections but no case of bronchiolitis nocardiosis have been described so far. A 58-year-old man, with history of controlled moderate allergic asthma, develop an increased cought in the last two years associated with dyspnea on exertion. Within two months, although ICS were increased to high doses, symptoms worsened due to a severe obstructive ventilatory disorder as revealed by pulmonary function tests (PFT). Small-scale lesions (< 10%) were found on chest computed tomography (CT). A bronchoalveolar lavage (BAL) found Nocardia abcessus. After six months of Sulfamethoxazole/Trimethoprim, PFT results improved and chest CT became completely normal. We therefore present the case of a bronchiolitis nocardiosis with several bronchial syndrome and the only immunosuppressive factor found were ICS.
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PURPOSE: Patients with pulmonary hypertension (PH) have long been advised to avoid exercise in fear of deterioration in right-sided heart function. Since the 2009 European Society of Cardiology guidelines, rehabilitation in expert centers is considered to have a specific role in care of patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). We report routine rehabilitation effects in patients with PH as a component of real-life multimodal treatment. METHODS: Patients with PAH or CTEPH were recommended for either in- or outpatient rehabilitation in addition to their usual care, unless there were practical problems or the patient declined. Assessment was conducted according to New York Heart Association classes, adverse events, 6 min-walk test, hemodynamics, and risk stratification after rehabilitation. RESULTS: Forty-one patients, 61% female, age 60 ±18 yr were included between March 2010 and May 2019. No major adverse events or deaths related to progression of right-sided heart failure were reported. Nevertheless, 22% of participants suffered adverse events in most cases not linked with physical activity. Rehabilitation as add-on to medical therapy and/or arterial deobstruction improved New York Heart Association class: mean difference, -0.39 (95% CI, -0.68 to -0.10), 6-min walk test: mean difference, 80 m (95% CI, 46-114), and was associated with improved right-sided heart hemodynamics. The risk assessment grade improved by -0.25 points (95% CI, -0.44 to -0.06) after rehabilitation. CONCLUSIONS: For patients with PAH or CTEPH, supervised rehabilitation as add-on to medical therapy and/or arterial deobstruction is safe and effective in improving patient and clinically related outcomes.
Subject(s)
Hypertension, Pulmonary , Pulmonary Arterial Hypertension , Humans , Female , Adult , Middle Aged , Aged , Male , Hypertension, Pulmonary/etiology , Walk Test , Outpatients , Exercise , Chronic DiseaseABSTRACT
Most patients with lung cancer are smokers and are of advanced age. They are therefore at high risk of having age- and lifestyle-related comorbidities. These comorbidities are subject to treatment or even polypharmacy. There is growing evidence of a link between lung cancer, comorbidities and medications. The relationships between these entities are complex. The presence of comorbidities and their treatments influence the time of cancer diagnosis, as well as the diagnostic and treatment strategy. On the other hand, cancer treatment may have an impact on the patient's comorbidities such as renal failure, pneumonitis or endocrinopathies. This review highlights how some comorbidities may have an impact on lung cancer presentation and may require treatment adjustments. Reciprocal influences between the treatment of comorbidities and anticancer therapy will also be discussed.
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INTRODUCTION: Several studies in COPD have shown a significant and early increase in the risk of cardiovascular mortality attributable to inhaled bronchodilators including long acting ß2 agonists (LABAs) and muscarinic antagonists (LAMAs). Cardiac autonomic system impairment may be a potential mechanism involved. METHODS: We performed a phase 4, investigator-initiated, prospective, randomized, blinded, cross-over trial (LAB-Card trial - NCT02872090) to evaluate the effect of two LAMAs and one LABA on the cardiac autonomic system in patients with COPD by using three major assessment approaches: heart rate variability (HRV, a predictor of cardiovascular death), baroreflex sensitivity (BRS) and autonomic function (tilt test). RESULTS: 34 patients attended four visits to receive either tiotropium 18µg, glycopyrronium 44µg, indacaterol 150 µg or placebo (lactose) in a randomized order followed by the assessment of HRV and BRS in supine position and after passive rising. Neither LAMAs (tiotropium or glycopyrronium) nor LABA (indacaterol) induced a higher LF/HF ratio (reflect of sympathetic/parasympathetic balance) measured in supine position at rest compared to placebo (primary outcome). Solely indacaterol induced an increase in heart rate compared to placebo. No significant differences were observed for HRV and BRS between active drugs and placebo in supine position or after passive rising. CONCLUSION: We did not found evidence of a deleterious effect of 2 LAMAs and one LABA on the autonomic cardiovascular control in COPD patients. Further investigations are needed to explore mechanisms by which long-acting bronchodilators may increase cardiovascular events in COPD.
Subject(s)
Bronchodilator Agents , Pulmonary Disease, Chronic Obstructive , Humans , Bronchodilator Agents/therapeutic use , Glycopyrrolate/therapeutic use , Tiotropium Bromide/therapeutic use , Adrenergic beta-2 Receptor Agonists/adverse effects , Prospective Studies , Pulmonary Disease, Chronic Obstructive/drug therapyABSTRACT
Background: Trastuzumab is used, alone or in conjunction with standard chemotherapy, to treat HER2-positive breast cancer (BC). Although it improves cancer outcomes, trastuzumab. can lead to cardiotoxicity. Physical exercise is a safe and effective supportive therapy in the management of side effects, but the cardioprotective effects of exercise are still unclear. Objectives: The primary aim of this study was to test whether trastuzumab-induced cardiotoxicity [left ventricular ejection fraction (LVEF) under 50%, or an absolute drop in LVEF of 10%] was reduced after a supervised exercise program of 3 months in patients with HER2-positive breast cancer. Secondary endpoints were to evaluate (i) cardiotoxicity rates using other criteria, (ii) cardiac parameters, (iii) cardiorespiratory fitness and (iv) whether a change in LVEF influences the cardiorespiratory fitness. Methods: 89 women were randomized to receive adjuvant trastuzumab in combination with a training program (training group: TG; n = 46) or trastuzumab alone (control group: CG; n = 43). The primary and secondary endpoints were evaluated at the end of the supervised exercise program of 3 months (T3). Results: After exercise program, 90.5 % of TG patients and 81.8% of CG patients did not exhibit cardiotoxicity. Furthermore, whatever the used criterion, percentage of patients without cardiotoxicity were greater in TG (97.6 and 100% respectively) than in CG (90.9 and 93.9% respectively). LVEF and GLS values remained stable in both groups without any difference between the groups. In contrast, at T3, peak VO2 (+2.6 mL.min-1.kg-1; 95%CI, 1.8 to 3.4) and maximal power (+21.3 W; 95%CI, 17.3 to 25.3) increased significantly in TG, whereas they were unchanged in CG (peak VO2: +0.2 mL.min-1.kg-1; 95%CI, -0.5 to 0.9 and maximal power: +0.7 W, 95%CI, -3.6 to 5.1) compared to values measured at T0. No correlation between LVEF changes and peak VO2 or maximal power was observed. Conclusion: A 12-week supervised exercise regimen was safe and improved the cardiopulmonary fitness in particular peak VO2, in HER2-positive BC patients treated with adjuvant trastuzumab therapy. The study is under powered to come to any conclusion regarding the effect on cardiotoxicity. Clinical trial registration: www.ClinicalTrials.gov, identifier: NCT02433067.
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The management of immunosuppressors in solid organ transplantation requires pharmacological therapeutic monitoring with regular adaptation of the dosage to the residual level. An obvious cause of these fluctuations is drug interactions, particularly for mTOR inhibitors and anti-calcineurin drugs, which are highly metabolized by cytochromes P450. A 72-year-old lung transplanted man, treated by tacrolimus and everolimus in the long term, had his residual immunosuppressor levels unbalanced by the introduction of sotorasib, which is used for metastatic pulmonary adenocarcinoma. This imbalance is explained by the fact that sotorasib is an inducer of CYP3A4 and an inhibitor of PGP, but the strength of the interaction has never been studied. This will have required a threefold increase in dosages and weekly monitoring before satisfactory residual levels were achieved.
Subject(s)
Lung Transplantation , Tacrolimus , Aged , Calcineurin Inhibitors , Drug Interactions , Everolimus/therapeutic use , Humans , Immunosuppressive Agents/pharmacology , Immunosuppressive Agents/therapeutic use , Male , Piperazines , Pyridines , Pyrimidines , Tacrolimus/therapeutic useABSTRACT
BACKGROUND: In patients undergoing balloon pulmonary angioplasty (BPA) for inoperable chronic thromboembolic pulmonary hypertension (CTEPH), single-centre series from expert centres have recognized a learning curve for the magnitude of haemodynamic benefits. OBJECTIVE: To report our 7-year experience with BPA, focusing on haemodynamic effects, complication rates and radiation exposure over time. METHODS: Patients with CTEPH who were treated with BPA between May 2013 and February 2020 were analysed during the 'initial period' versus the 'recent period' (split date: March 2017). RESULTS: Among 192 patients who underwent at least one BPA procedure, 156 were included in the safety/radiation analysis and 119 were included in the efficacy analysis. During the 'recent period' versus the 'initial period', the median [interquartile range] number of procedures per patient was higher (4.5 [4.0-6.0] vs. 4.0 [3.0-4.0]; P=0.03), as was the number of dilated vessels per procedure (4.0 [3.5-5.0] vs. 3.5 [3.0-4.0]; P=0.002). Changes in haemodynamic parameters were also greater (mean pulmonary artery pressure: -22% [-31% to -14%] vs. -37% [-44% to -29%]; P=0.001; pulmonary vascular resistance: -38% [-51% to -8%] vs. -53% [-69% to -33%]; P=0.002); complication rates were similar (5.7% vs. 9.3% of procedures; P=0.38); and radiation exposure was lower (effective dose per patient: 43.9 [31.6-66.5] vs. 67.8 [47.9-101.9] mSv; P<0.001). CONCLUSION: Our analysis is consistent with a learning curve for the magnitude of haemodynamic improvements. The complication rate was low and did not change over time, but radiation exposure decreased.
Subject(s)
Angioplasty, Balloon , Hypertension, Pulmonary , Pulmonary Embolism , Radiation Exposure , Angioplasty, Balloon/adverse effects , Chronic Disease , Hemodynamics , Humans , Hypertension, Pulmonary/diagnosis , Hypertension, Pulmonary/etiology , Hypertension, Pulmonary/therapy , Pulmonary Artery , Pulmonary Embolism/diagnostic imaging , Pulmonary Embolism/therapy , Radiation Exposure/adverse effects , Treatment OutcomeABSTRACT
Importance: Rates of 30-day readmissions following hospitalization for pneumonia are used to publicly report on hospital performance and to set financial penalties for the worst-performing hospitals. However, the rate of avoidable readmission following hospitalization for pneumonia is undefined. Objective: To assess how often 30-day readmissions following hospitalization for community-acquired pneumonia (CAP) are avoidable. Design, Setting, and Participants: This cohort study analyzed the results of an independent review of readmissions following hospitalization for CAP within 30 days among patients discharged from 2 large hospitals in France in 2014. Structured clinical records including clinical information (ie, baseline characteristics, physical examination, laboratory findings, x-ray or computed tomography scan findings, discharge plan, and treatments) for both index and readmission stays were independently reviewed by 4 certified board physicians. All consecutive adult patients hospitalized in 2014 with a diagnosis of CAP in our 2 eligible hospitals were eligible. All analyses presented were performed in March 2021. Main Outcomes and Measures: Avoidable readmission within 30 days of discharge from index hospitalization. The likelihood that a readmission was avoidable was quantified using latent class analysis based on the independent reviews. A readmission was considered avoidable if Bayes posterior probability exceeded 50%. Results: The total analytical sample consisted of 1150 index hospital stays with a diagnosis of CAP, which included 651 (56.6%) male patients. The median (IQR) age for all patients was 77.8 (IQR, 62.7-86.4) years. Out of the 1150 index hospital stays, 98 patients (8.5%) died in hospital, and 108 (9.4%) unplanned readmissions were found. Overall, 15 readmissions had a posterior probability of avoidability exceeding 0.50 (13.9% of the 108 unplanned readmissions; 95% CI, 8.0%-21.9%). The median (IQR) delay between the hospital discharge index and readmission was considerably shorter when readmission was deemed avoidable (4 [6-21] days vs 12 [2-18] days; P = .02). Conclusions and Relevance: Only a small number of readmissions following hospitalization for CAP were deemed avoidable, comprising less than 10% of all readmissions. Shorter time interval between hospitalization discharge and readmission was associated with avoidability.
Subject(s)
Community-Acquired Infections , Pneumonia , Adult , Aged , Aged, 80 and over , Bayes Theorem , Cohort Studies , Community-Acquired Infections/epidemiology , Community-Acquired Infections/therapy , Hospitalization , Humans , Incidence , Male , Middle Aged , Patient Readmission , Pneumonia/epidemiology , Pneumonia/therapyABSTRACT
The progression of chronic obstructive pulmonary disease (COPD) is characterized by episodes of acute exacerbation (AECOPD) of symptoms, decline in respiratory function, and reduction in quality-of-life increasing morbi-mortality and often requiring hospitalization. Exacerbations can be triggered by environmental exposures, changes in lifestyle, and/or physiological and psychological factors to greater or lesser extents depending on the individual's COPD phenotype. The prediction and early detection of an exacerbation might allow patients and physicians to better manage the acute phase. We summarize the recent scientific data on remote telemonitoring (TM) for the prediction and management of acute exacerbations in COPD patients. We discuss the components of remote monitoring platforms, including the integration of environmental monitoring data; patient reported outcomes collected via interactive Smartphone apps, with data from wearable devices that monitor physical activity, heart rate, etc.; and data from medical devices such as connected non-invasive ventilators. We consider how telemonitoring and the deluge of data it potentially generates could be combined with electronic health records to provide personalized care and multi-disease management for COPD patients.
ABSTRACT
Excessive ventilation (VÌE) during exercise, ascribed to heightened neural ventilatory drive and/or to increased "wasted" ventilation, is a feature of chronic thromboembolic pulmonary hypertension (CTEPH). In selected CTEPH patients, balloon pulmonary angioplasty (BPA) allows near-normalization of resting haemodynamic parameters but does not allow excess exercise hyperventilation to normalize. Neural ventilatory drive can be estimated by studying how arterial PCO2 (PaCO2), end-tidal PCO2 (PETCO2), VÌE and CO2 output (VÌCO2) change across the exercise-to-recovery transition during a cardiopulmonary exercise test. Increased "wasted" ventilation can be quantified by the physiological dead space fraction of tidal volume (VD/VT) calculated with the Enghoff simplification of the Bohr equation. These measurements were made before and after BPA in 22 CTEPH patients without significant cardiac and/or pulmonary comorbidities. Our observations suggest that before BPA, excessive hyperventilation was secondary to both heightened neural ventilatory drive and increased "wasted" ventilation; after BPA, measurements made across the exercise-to-recovery transition suggest that heightened neural ventilatory drive was no longer present.