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The article presents a case study of a 29-year-old man with Behcet's disease experiencing dyspnea, revealing cardiovascular limitations and impaired O2 extraction. Topics discussed include cardiovascular contributors to dyspnea, peripheral O2 extraction impairment, and the importance of invasive exercise tests for comprehensive evaluation.

This article discusses the role of pulmonary function tests (PFTs) in the management of pulmonary hypertension (PH). PFTs are important in diagnosing PH and assessing its severity and prognosis. The article presents a case study of a young woman with idiopathic pulmonary arterial hypertension (IPAH) and describes the changes in her PFT results over time. It also explores the potential mechanisms underlying lung function disturbances in PH. The article emphasizes the value of PFTs in monitoring PH and improving treatment approaches. [Extracted from the article]

Rationale: Post-coronavirus disease 2019 (COVID-19) survivors frequently have dyspnoea that can lead to exercise intolerance and lower quality of life. Despite recent advances, the pathophysiological mechanisms of exercise intolerance in the post-COVID-19 patients remain incompletely characterised. The objectives of the present study were to clarify the mechanisms of exercise intolerance in post-COVID-19 survivors after hospitalisation., Methods: This prospective study evaluated consecutive patients previously hospitalised due to moderate-to-severe/critical COVID-19. Within mean±sd 90±10 days of onset of acute COVID-19 symptoms, patients underwent a comprehensive cardiopulmonary assessment, including cardiopulmonary exercise testing with earlobe arterialised capillary blood gas analysis., Measurements and Main Results: 87 patients were evaluated; mean±sd peak oxygen consumption was 19.5±5.0 mL·kg -1 ·min -1 , and the tertiles were ≤17.0, 17.1-22.2 and ≥22.3 mL·kg -1 ·min -1 . Hospitalisation severity was similar among the three groups; however, at the follow-up visit, patients with peak oxygen consumption ≤17.0 mL·kg -1 ·min -1 reported a greater sensation of dyspnoea, along with indices of impaired pulmonary function, and abnormal ventilatory, gas-exchange and metabolic responses during exercise compared to patients with peak oxygen consumption >17 mL·kg -1 ·min -1 . By multivariate logistic regression analysis (receiver operating characteristic curve analysis) adjusted for age, sex and prior pulmonary embolism, a peak dead space fraction of tidal volume ≥29 and a resting forced vital capacity ≤80% predicted were independent predictors of reduced peak oxygen consumption., Conclusions: Exercise intolerance in the post-COVID-19 survivors was related to a high dead space fraction of tidal volume at peak exercise and a decreased resting forced vital capacity, suggesting that both pulmonary microcirculation injury and ventilatory impairment could influence aerobic capacity in this patient population., Competing Interests: Conflict of interest: M.L. Lafetá has nothing to disclose. Conflict of interest: V.C. Souza has nothing to disclose. Conflict of interest: T.C.F. Menezes has nothing to disclose. Conflict of interest: C.G.Y. Verrastro has nothing to disclose. Conflict of interest: F.J. Mancuso has nothing to disclose. Conflict of interest: A.L.P. Albuquerque has nothing to disclose. Conflict of interest: S.E. Tanni is President of the Sao Paulo Thoracic Society outside the submitted work. Conflict of interest: M. Izbicki has nothing to disclose. Conflict of interest: J.P. Carlstron has nothing to disclose. Conflict of interest: L.E. Nery has nothing to disclose. Conflict of interest: R.K.F. Oliveira report grants from the National Council for Scientific and Technological Development (CNPq), Brazil (grant 313284/2021-0), and personal fees from Janssen Brazil, outside the submitted work. Conflict of interest: P.A. Sperandio has nothing to disclose. Conflict of interest: E.V.M. Ferreira reports speaker fees from Janssen, and personal fees from Aché, AstraZeneca, Bayer, Boeringer, GSK, Novo Nordisk, Jassen-Cilag, J&J and Zambon, outside the submitted work., (Copyright ©The authors 2023.)

Patients with COPD present with systemic vascular malfunctioning and their microcirculation is possibly more fragile to overcome an increase in the sympathetic vasoconstrictor outflow during sympathoexcitatory situations. To test the skeletal muscle microvascular responsiveness to sympathoexcitation, we asked patients with COPD and age- and sex-matched controls to immerse a hand in iced water [Cold Pressor Test (CPT)]. Near-infrared spectroscopy detection of the indocyanine green dye in the intercostal and vastus lateralis microcirculation provided a blood flow index (BFI). BFI divided by mean blood pressure (MBP) provided an index of microvascular conductance (BFI/MBP). The CPT decreased BFI and BFI/MBP in the intercostal (P = 0.01 and < 0.01, respectively) and vastus lateralis (P = 0.08 and 0.03, respectively) only in the COPD group, and the per cent BFI and BFI/MBP decrease was similar between muscles (P = 0.78 and 0.85, respectively). Thus, our findings support that sympathoexcitation similarly impairs intercostal and vastus lateralis microvascular regulation in patients with COPD., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Pulmonary arterial hypertension (PAH) is associated with increased right ventricular (RV) afterload, RV dysfunction and decreased peak oxygen uptake (pVO 2 ). However, the pulmonary hemodynamic mechanisms measured by exercise right heart catheterization (RHC) that contribute to reduced pVO 2 in idiopathic PAH (IPAH) are not completely characterized. Therefore, we sought to evaluate the exercise RHC determinants of pVO 2 in patients with IPAH., Methods: 519 consecutive patients with suspected and/or confirmed pulmonary hypertension were prospectively screened to identify 20 patients with IPAH. All IPAH patients were prospectively evaluated with resting and exercise RHC and cardiopulmonary exercise testing., Results: 85% of the patients were female; the median age was 34[29-42] years old. At peak exercise, mean pulmonary arterial (PA) pressure was 76 ± 17 mmHg, PA wedge pressure was 14 ± 5 mmHg, cardiac output (CO) was 5.7 ± 1.9 L/min, pulmonary vascular resistance was 959 ± 401 dynes/s/cm 5 and PA compliance was 0.9[0.6-1.2] ml/mmHg. On univariate analysis, pVO2 positively correlated to peak CO, peak cardiac index, peak stroke volume index, peak RV stroke work index (RVSWI) and peak oxygen saturation. There was a negative correlation between pVO 2 and Δ (rest to peak change) PA compliance. In age-adjusted multivariate model, peak RVSWI (Coefficient = 0.15, Beta = 0.63, 95% CI [0.07-0.22], p < 0.01) and ΔPA compliance (Coefficient = -2.51, Beta = -0.43, 95% CI [-4.34-(-0.68)], p = 0.01) had the best performance predicting pVO 2 (R 2  = 0.66)., Conclusions: In conclusion, a load dependent measurement of RV function (RVSWI) and the pulsatile component of RV afterload (ΔPA compliance) significantly influence pVO 2 in IPAH, further highlighting the pivotal role of hemodynamic coupling to IPAH exercise capacity., Competing Interests: Declaration of Competing Interest None., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background and Objective: Peak oxygen consumption (pVO 2 ), determined from CPET, provides a valuable indication of PAH severity and patient prognosis. However, CPET is often contraindicated in severe PAH and frequently terminated prior to achievement of a sufficient exercise effort. We sought to determine whether in PAH low-intensity [i.e. freewheeling exercise (FW)] exercise reveals abnormal V E /VCO 2 and P ET CO 2 responses that are associated with pVO 2 and serve as indices of PAH risk stratification and mortality., Methods: Retrospective analysis of CPET from 97 PAH patients and 20 age-matched controls was undertaken. FW V E /VCO 2 and P ET CO 2 were correlated with pVO 2 % age-predicted. Prognostication analysis was conducted using pVO 2  > 65% age-predicted, as known to represent a low mortality risk. Primary outcome was mortality from any cause., Results: FW P ET CO 2 was correlated with pVO 2 (P < 0.0001; r = 0.52), while FW V E /VCO 2 was not (P = 0.13; r = -0.16). ROC curve analyses showed that FW P ET CO 2 (AUC = 0.659), but not FW V E /VCO 2 (AUC = 0.587), provided predictive information identifying pVO 2  > 65% age-predicted (best cut-off value of 28 mm Hg). By Cox analysis, FW P ET CO 2  < 28 mm Hg remained a predictor of mortality after adjusting for age and PAH aetiology (HR: 2.360, 95% CI: 1.144-4.866, P = 0.020)., Conclusion: Low P ET CO 2 during FW is associated with reduced pVO 2 in PAH and provides predictive information for PAH risk stratification and prognostication., (© 2020 Asian Pacific Society of Respirology.)

Six-minute walk distance (6MWD) assessment is recommended for pulmonary arterial hypertension multidimensional risk stratification. However, current 6MWD cut-off values were mainly derived from North American and European pulmonary arterial hypertension registries. Therefore, it is unknown if such cut-off values broadly apply to other geographical populations. In this study, we aimed to identify 6MWD cut-off values for Brazilian pulmonary arterial hypertension patients and to contrast our findings to current international Pulmonary Hypertension guidelines recommendations. One-hundred four consecutive pulmonary arterial hypertension patients were allocated in groups according to their 6MWD, considering 50 m as a clinically relevant 6MWD difference. Next, patients were categorized into different 6MWD ranges based on similar survival rates in each group: < 250 m, 250-400 m, and >400 m. The study outcome was all-cause mortality and transplantation according to the 6MWD range. Survival was truncated at five years. Median follow-up period was 4.35 years (0.48-5.00). Survival rates at 1, 2, 3, and 5 years were 96%, 89%, 81%, and 73%, respectively. Cox analyses adjusted for age, sex, and pulmonary arterial hypertension etiology showed that 6MWD < 250 m and >400 m were associated with higher and lower risk of all-cause mortality and transplantation. According to Harrell's c-statistic, the prognostic discrimination of the 6MWD cut-off value identified by the current study was 0.70 while international Pulmonary Hypertension guidelines 6MWD cut-offs value was 0.61. In conclusion, our findings suggest that 6MWD geographical variations should be considered when assessing risk stratification in pulmonary arterial hypertension., (© The Author(s) 2020.)

Background: Increased ventilatory (.VE) response to carbon dioxide output (.VCO2) is a key finding of incremental cardiopulmonary exercise testing in both heart failure and pulmonary arterial hypertension (PAH). As with heart failure, measures of excessive exercise ventilation considering high-to-peak exercise .VE-VCO2 might have higher prognostic relevance than those restrained to sub-maximal exercise in PAH., Design: Cross-sectional and observational study on a tertiary center., Methods: Eighty-four patients (36 idiopathic and 48 with associated conditions) were followed up for up to five years. Excessive exercise ventilation was calculated as a slope (Δ .VE/Δ .VCO2 to the respiratory compensation point (RCP) and to exercise cessation (PEAK)) and as a ratio (.VE-VCO2 at the anaerobic threshold (AT) and at PEAK)., Results: Thirteen patients died and three had atrial septostomy. Multivariable regression analyses revealed that Δ .VE/Δ .VCO2(PEAK) <55 and .VE/.VCO2(PEAK) <57 were better related to prognosis than Δ .VE/Δ .VCO2(RCP) and .VE/.VCO2(AT) (p < 0.01). Δ oxygen uptake (.VO2)/Δ work rate >5.5 ml/min per W was the only other independent prognostic index. According to a Kaplan-Meier survival analysis, 96.9% (90.8% to 100%) of patients showing Δ .VE/Δ .VCO2(PEAK) <55 and Δ .VO2/Δ work rate >5.5 ml/min per W were free from a PAH-related event. In contrast, 74.7% (70.1% to 78.2%) with both parameters outside these ranges had a negative outcome., Conclusion: Measurements of excessive exercise ventilation which consider all data points maximize the usefulness of incremental cardiopulmonary exercise testing in the prognosis evaluation of PAH., (© The European Society of Cardiology 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.)

Chronic hypersensitivity pneumonitis is a common fibrotic interstitial lung disease. The prevalence of pulmonary hypertension diagnosed by right heart catheterisation and its cardiopulmonary function findings in patients with chronic hypersensitivity pneumonitis are unknown. Consecutive symptomatic patients with chronic hypersensitivity pneumonitis were prospectively evaluated. All patients were submitted to right heart catheterisation, pulmonary function testing, a 6-min walk test, echocardiography, blood gas determination and N-terminal pro-brain natriuretic peptide analyses. Nonhypoxaemic patients also underwent incremental cardiopulmonary exercise testing. 50 patients underwent right heart catheterisation; 25 (50%) of these had pulmonary hypertension and 22 (44%) had a pre-capillary haemodynamic pattern. The patients with pre-capillary pulmonary hypertension had lower forced vital capacity (mean ± sd 50 ± 17% versus 69 ± 22% predicted, p<0.01), carbon monoxide diffusing capacity (37 ± 12% versus 47 ± 14% predicted, p<0.01), arterial oxygen tension (median (interquartile range) 59.0 (47.8-69.3) versus 73.0 (62.2-78.5) mmHg, p<0.01) and saturation after the 6-min walk test (78 ± 8% versus 86 ± 7%, p<0.01). In pre-capillary pulmonary hypertension, oxygen uptake was also lower at the anaerobic threshold (41 ± 11% versus 50 ± 8% predicted, p=0.04) and at peak exercise (12.8 ± 1.6 versus 15.0 ± 2.5 mL · kg(-1) · min(-1), p=0.02). Pre-capillary pulmonary hypertension is common in symptomatic chronic hypersensitivity pneumonitis and is related to interstitial lung disease severity. Additionally, pulmonary hypertension is more prevalent in hypoxaemic patients with impaired lung function and exercise capacity., (©ERS 2014.)

Background: Pulmonary arterial hypertension (PAH) is characterized by a pulmonary capillary wedge pressure (PCWP) of ≤15 mm Hg, given a normal left ventricular filling pressure (LVFP). However, recent studies have shown that, in PAH patients, diagnosis based on PCWP can erroneously classify a significant number of patients compared with diagnosis based on left ventricular end-diastolic pressure (LVEDP). Therefore, we sought to compare the diagnostic accuracy of end-expiratory PCWP and LVEDP measurements in patients suspected of having pulmonary hypertension (PH)., Methods: We reviewed the hemodynamic data from 122 patients suspected of having PH who underwent simultaneous right- and left-side heart catheterizations at a PH referral center from 2006 to 2011., Results: PH was diagnosed in 105 patients, 79% of whom (n = 83) showed a pre-capillary pattern according to the LVEDP measurement. Ninety percent of patients with PCWP ≤15 mm Hg were correctly classified as having pre-capillary PH. However, 39% of patients with a PCWP >15 mm Hg had LVEDP ≤15 mm Hg and would have been erroneously diagnosed with pulmonary venous hypertension based on their PCWP measurements alone. The sensitivity and specificity was 0.89 and 0.64, respectively. A Bland-Altman analysis of the PCWP and LVEDP measurements revealed a mean bias of 0.3 mm Hg with 95% limits of agreement of -7.2 to 7.8 mm Hg., Conclusions: A PCWP ≤15 mm Hg was found to be a reliable indicator of normal LVFP in pre-capillary PH patients. When measured properly and analyzed in the clinical context, PCWP is a valuable tool for accurate diagnosis of PAH., (© 2014 International Society for Heart and Lung Transplantation Published by International Society for the Heart and Lung Transplantation All rights reserved.)

Background: Delayed postexercise heart rate recovery (HRR) has been associated with disability and poor prognosis in chronic cardiopulmonary diseases. The usefulness of HRR to predict exercise impairment and mortality in patients with pulmonary arterial hypertension (PAH), however, remains largely unexplored., Methods: Seventy-two patients with PAH of varied etiology (New York Heart Association classes I-IV) and 21 age- and gender-matched controls underwent a maximal incremental cardiopulmonary exercise test (CPET), with heart rate being recorded up to the fifth minute of recovery., Results: Heart rate recovery was consistently lower in the patients compared with the controls (P < .05). The best cutoff for HRR in 1 minute (HRR(1 min)) to discriminate the patients from the controls was 18 beats. Compared with patients with HRR(1 min) ≤ 18 (n = 40), those with HRR(1 min) >18 (n = 32) had better New York Heart Association scores, resting hemodynamics and 6-minute walking distance. In fact, HRR(1 min) >18 was associated with a range of maximal and submaximal CPET variables indicative of less severe exercise impairment (P < .05). The single independent predictor of HRR(1 min) ≤ 18 was the 6-minute walking distance (odds ratio [95% CI] 0.99 [0.98-1.00], P < .05). On a multiple regression analysis that considered only CPET-independent variables, HRR(1 min) ≤ 18 was the single predictor of mortality (hazard ratio [95% CI] 1.19 [1.03-1.37], P < .05)., Conclusions: Preserved HRR(1 min) (>18 beats) is associated with less impaired responses to incremental exercise in patients with PAH. Conversely, a delayed HRR(1 min) response has negative prognostic implications, a finding likely to be clinically useful when more sophisticated (and costlier) analyses provided by a full CPET are not available., (Copyright © 2012 Mosby, Inc. All rights reserved.)