Su-Gang Gong

Usefulness of decrease in oxygen uptake efficiency to identify gas exchange abnormality in patients with idiopathic pulmonary arterial hypertension.

Background Decline in oxygen uptake efficiency (OUE), especially during exercise, is found in patients with chronic heart failure. In this study we aimed to test the validity and usefulness of OUE in evaluating gas exchange abnormality of patients with idiopathic pulmonary arterial hypertension (IPAH). Methods We retrospectively investigated the cardiopulmonary exercise test (CPET) with gas exchange measurements in 32 patients with confirmed IPAH. All patients also had resting hemodynamic measurements and pulmonary function test (PFT). Sixteen healthy subjects, matched by age, sex, and body size were used as controls, also had CPET and PFT measurements. Results In IPAH patients, the magnitude of absolute and percentage of predicted (%pred) oxygen uptake efficiency slope (OUES) and oxygen uptake efficiency plateau (OUEP), as well as several other CPET parameters, were strikingly worse than healthy subjects (P<0.0001). Pattern of changes in OUE in patients is similar to that in controls, In IPAH patients, OUE values at rest, warming up, anaerobic threshold and peak exercise were all significantly lower than in normal (P<0.0001). OUEP%pred, better than OUES%pred, correlated significantly with New York Heart Association (NYHA) functional Class (r = −0.724, P<0.005), Total Pulmonary Vascular Resistance (TPVR) (r = −0.694, P<0.005), diffusing capacity for carbon monoxide (DLCO) (r = 0.577, P<0.05), and the lowest ventilation versus CO2 output ratio during exercise (LowestV˙E/V˙CO2) (r = −0.902, P<0.0001). In addition, the coefficient of variation (COV) of OUEP was lower (20.9%) markedly than OUES (34.3%) (P<0.0001). Conclusions In patients with IPAH, OUES and OUEP are both significantly lower than the healthy subjects. OUEP is a better physiological parameter than OUES in evaluating the gas exchange abnormality of patients with IPAH.

Comparative effectiveness of sildenafil for pulmonary hypertension due to left heart disease with HFrEF

There is no cure for pulmonary hypertension due to left heart disease (PH-LHD), but the rationale for using sildenafil to treat pulmonary arterial hypertension with heart failure with reduced ejection fraction (HFrEF) has been supported by short-term studies. We performed a meta-analysis to evaluate the effectiveness of sildenafil for PH-LHD with HFrEF. A systematic literature search of PubMed, EMBASE and the Cochrane Central Register of Controlled Trials was conducted from inception through October 2014 for randomized trials and for observational studies with control groups, evaluating the effectiveness of sildenafil to treat PH-LHD with HFrEF. Sildenafil therapy decreased pulmonary arterial systolic pressure both at the acute phase and at the 6-month follow-up (weighted mean difference (WMD): −6.03 mm Hg, P=0.02; WMD: −11.47 mm Hg, P<0.00001, respectively). Sildenafil was found to reduce mean pulmonary artery pressure (WMD: −3 mm Hg, P=0.0004) and pulmonary vascular resistance (WMD: −60.0 dynes cm−5, P=0.01) at the 3-month follow-up. Oxygen consumption at peak significantly increased to 3.66 ml min−1 kg−1 (P<0.00001), 3.36 ml min−1 kg−1 (P<0.00001) and 2.60 ml min−1 kg−1 (P=0.03) at 3, 6 and 12 months, respectively. There were significant reductions in ventilation to CO2 production slope of −2.00, −4.68 and −7.12 at 3, 6 and 12 months, respectively (P<0.00001). Sildenafil was superior to placebo regarding left ventricular ejection fraction at the 6-month follow-up (WMD: 4.35, P<0.00001), and it significantly improved quality of life. Sildenafil therapy could effectively improve pulmonary hemodynamics and cardiopulmonary exercise testing measurements of PH-LHD with HFrEF, regardless of acute or chronic treatment.

Oxygen uptake is more efficient in idiopathic pulmonary arterial hypertension than in chronic thromboembolic pulmonary hypertension

The responses of oxygen uptake efficiency (OUE) during cardiopulmonary exercise training (CPET) have not been reported in patients with pulmonary hypertension. We aimed to investigate the differences in OUE between patients with idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic pulmonary hypertension (CTEPH).

Exercise Physiology and Pulmonary Hemodynamic Abnormality in PH Patients with Exercise Induced Venous-To-Systemic Shunt

Objectives To identify the pulmonary hypertension (PH) patients who develop an exercise induced venous-to-systemic shunt (EIS) by performing the cardiopulmonary exercise test (CPET), analyse the changes of CPET measurements during exercise and compare the exercise physiology and resting pulmonary hemodynamics between shunt-PH and no-shunt-PH patients. Methods Retrospectively, resting pulmonary function test (PFT), right heart catheterization (RHC), and CPET for clinical evaluation of 104 PH patients were studied. Results Considering all 104 PH patients by three investigators, 37 were early EIS+, 61 were EIS-, 3 were late EIS+, and 3 others were placed in the discordant group. PeakVO2, AT and OUES were all reduced in the shunt-PH patients compared with the no-shunt-PH subjects, whereas VE/VCO2 slope and the lowest VE/VCO2 increased. Besides, the changes and the response characteristics of the key CPET parameters at the beginning of exercise in the shunt group were notably different from those of the no shunt one. At cardiac catheterization, the shunt patients had significantly increased mean pulmonary artery pressure (mPAP), mean right atrial pressure (mRAP) and pulmonary vascular resistance (PVR), reduced cardiac output (CO) and cardiac index (CI) compared with the no shunt ones (P<0.05). Resting CO was significantly correlated with exercise parameters of AT (r = 0.527, P<0.001), OUES (r = 0.410, P<0.001) and Peak VO2 (r = 0.405, P<0.001). PVR was significantly, but weakly, correlated with the above mentioned CPET parameters. In Conclusions CPET may allow a non-invasive method for detecting an EIS and assessing the severity of the disease in PH patients.

Impact of anaemia on lung function and exercise capacity in patients with stable severe chronic obstructive pulmonary disease

Objective This study intended to search for potential correlations between anaemia in patients with severe chronic obstructive pulmonary disease (COPD; GOLD stage III) and pulmonary function at rest, exercise capacity as well as ventilatory efficiency, using pulmonary function test (PFT) and cardiopulmonary exercise testing (CPET). Setting The study was undertaken at Shanghai Pulmonary Hospital, a tertiary-level centre affiliated to Tongji University. It caters to a large population base within Shanghai and referrals from centres in other cities as well. Participants 157 Chinese patients with stable severe COPD were divided into 2 groups: the anaemia group (haemoglobin (Hb) <12.0 g/dL for males, and <11 g/dL for females (n=48)) and the non-anaemia group (n=109). Primary and secondary outcome measures Arterial blood gas, PFT and CPET were tested in all patients. Results (1) Diffusing capacity for carbon monoxide (DLCO) corrected by Hb was significantly lower in the anaemia group ((15.3±1.9) mL/min/mm Hg) than in the non-anaemia group ((17.1±2.1) mL/min/mm Hg) (p<0.05). A significant difference did not exist in the level of forced expiratory volume in 1 s (FEV1), FEV1%pred, FEV1/forced vital capacity (FVC), inspiratory capacity (IC), residual volume (RV), total lung capacity (TLC) and RV/TLC (p>0.05). (2) Peak Load, Peak oxygen uptake (), Peak %pred, Peak , Peak pulse and the ratio of increase to WR increase () were significantly lower in the anaemia group (p<0.05); however, Peak minute ventilation (VE), Lowest /carbon dioxide output () and Peak dead space/tidal volume ratio (VD/VT) were similar between the 2 groups (p>0.05). (3) A strong positive correlation was found between Hb concentration and Peak in patients with anaemia (r=0.702, p<0.01). Conclusions Anaemia has a negative impact on gas exchange and exercise tolerance during exercise in patients with severe COPD. The decrease in amplitude of Hb levels is related to the quantity of oxygen uptake.

Cardiopulmonary exercise testing improves diagnostic specificity in patients with echocardiography‐suspected pulmonary hypertension

Doppler echocardiography is usually the first diagnostic investigation for patients suspected with pulmonary hypertension (PH), but it is often inaccurate when used alone, especially in mild PH.

Oxygen Uptake Efficiency Slope, an Objective Submaximal Parameter in Evaluating Exercise Capacity in Pulmonary Thromboembolism☆☆☆☆☆☆

Objective: The objective of this article was to study the oxygen uptake efficiency, an index of cardiopulmonary functional reserve that can be based upon a submaximal exercise effort, in pulmonary thromboembolism (PE) by performing the cardiopulmonary exercise test. Materials and Methods: The cardiopulmonary exercise test with simultaneous respiratory gas measurement was performed in 50 patients with PE and in 50 healthy individuals. All subjects also underwent the pulmonary function test. Peak oxygen uptake (peak VO2), anaerobic threshold (AT), oxygen uptake efficiency slope (OUES), oxygen uptake efficiency plateau (OUEP) and oxygen uptake efficiency at anaerobic threshold (OUE@AT), were determined. Results: (1) Compared with the controls, the patients with PE had lower peak VO2, AT, OUES, OUEP and OUE@AT (P < 0.001). (2) In patients with PE, oxygen uptake efficiency (OUE = VO2/VE) at warming up, AT and peak exercise but not rest, were indicated statistically lower than the controls. The OUE in normal subjects increased as unloaded exercise began, and then increased further to OUEP just before the AT. Thereafter, the OUE decreased gradually until peak exercise. In contrast, the rate of changes of the OUE in patients with PE was relatively mild during exercise. (3) Of all the submaximal parameters, OUES correlated best with peak VO2 (r = 0.712, P < 0.001). Conclusions: The oxygen uptake efficiency of patients with PE was lower than the controls during exercise. The OUE is an objective measure of cardiopulmonary reserve that does not require a maximal exercise effort. Therefore, OUES could be helpful to assess exercise performance in patients with PE who are unable to perform a maximal exercise test in early recovery stage.

Efficacy and Safety of a Calcium Sensitizer, Levosimendan, in Patients with Right Heart Failure due to Pulmonary Hypertension.

Despite using vasoactive and pulmonary hypertension (PH) specific therapies, the in‐hospital mortality of severe PH with right heart failure (RHF) is high. We conducted a prospective analysis evaluating the efficacy and safety of levosimendan in PH patients with severe acute RHF.

Sex-specific cardiopulmonary exercise testing indices related to hemodynamics in idiopathic pulmonary arterial hypertension.

Background: Many studies have highlighted sex preponderance in idiopathic pulmonary arterial hypertension (IPAH). It is well established that there are differences in exercise capacities in the two sexes but how much of that difference reflects on disease severity or correlates to markers of severity in the two sexes is still not clear. Right heart catheterization (RHC) and cardiopulmonary exercise testing (CPET) have been widely used for assessing functional capacity, prognosis and treatment response in IPAH. We aimed to investigate the ‘sex-specific’ CPET parameters in relation to hemodynamics in IPAH. Methods: Data were retrieved from 30 males and 53 females [mean ± standard deviation (SD) age: 39.6 ± 17.2 and 37.5 ± 12.0] stable IPAH patients who underwent both RHC and CPET at Shanghai Pulmonary Hospital from 2010 to 2016. Univariate and forward/backward multiple stepwise regression analysis was performed to assess the prognostic value of CPET and hemodynamic parameters. Results: There were no significant differences in clinical variables between men and women. Peak workload, peak oxygen uptake, anaerobic threshold (AT), peak minute ventilation, carbon dioxide output, O2 pulse and oxygen uptake efficiency slope were significantly higher in men compared with women (p < 0.05). Several CPET indexes correlated with hemodynamics. Pulmonary vascular resistance (PVR) and cardiac output (CO) were distinctly different between the sexes. Peak end-tidal partial pressure of CO2 (PETCO2) was an independent predictor of PVR elevation in all patients and in men. Peak maximum oxygen consumption (VO2) was independently predictive of CO decline in all patients and in men. Only peak O2 pulse was an independent predictor of increased PVR and decreased CO in women. Conclusions: Even after adjusting for age, body mass index and World Health Organization functional class, different CPET parameters correlated with PVR elevation and CO decline in men and women differently, which could potentially better predict severity in men and women with IPAH.

Chronotropic Incompetence and its Relation to Exercise Intolerance in Chronic Obstructive Pulmonary Disease

Background: To study the relationship between chronotropic incompetence (CI) and disease severity and to assess the effect of CI on exercise capacity in patients with chronic obstructive pulmonary disease (COPD). Materials and Methods: Arterial blood gas analysis, pulmonary function test and cardiopulmonary exercise testing were conducted in 60 patients with stable COPD and 45 healthy volunteers. CI was defined using the chronotropic response index (CRI = (peak heart rate‐resting heart rate) / (220‐age‐resting heart rate). Based on CRI, patients with COPD were divided into the normal chronotropic group (n = 23) and CI group (n = 37). Results: CI was present in 61.7% of the patients with COPD. Exercise capacity (peak oxygen uptake as percentage of predicted value, peak VO2%pred), peak heart rate and CRI were significantly lower in patients with COPD than in controls. However, resting heart rate was significantly higher than in controls. FEV1%pred and exercise capacity were significantly decreased in the CI group when compared with those in the normotropic group. There was significant association between CRI with FEV1%pred and peak VO2%pred. Multivariate regression analysis showed that CRI and FEV1%pred were independent predictors of exercise capacity in patients with COPD. A cutoff of 0.74 for the CRI showed a specificity of 94.1% in predicting patients with a peak VO2%pred < 60%. Conclusions: CRI was associated with disease severity in patients with COPD. CI may be an important parameter to reflect exercise capacity in patients with COPD.