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Background: Exercise-induced increase in pulmonary artery systolic pressure (PASP) as a possible measure of right ventricular (RV) contractile reserve has been shown to predict survival in severe pulmonary hypertension. However, RV contractile reserve can also be measured by changes in stroke volume (SV), tricuspid annular plane systolic excursion (TAPSE), or tricuspid annular systolic velocity (S'). The limits of normal values and the functional significance of these changes in healthy subjects are not well known. Methods: In this prospective study, 90 healthy subjects (45 male, mean age 39 ± 13 years) underwent exercise stress echocardiography with measurement of TAPSE, S', TAPSE/PASP, SV, and PASP at rest and peak exercise. Maximum and minimum normal values were reported for all indices. Results: Normal values of exercise-induced changes (Δ) were 4 to 10 mm for TAPSE, 6 to 14 cm/s for S', 12 to 57 mm Hg for PASP, 0 to 96 mL for SV, and −1.2 to 0 mm/mm Hg for TAPSE/PASP. At peak exercise, women showed lower ΔTAPSE/PASP, ΔPASP, ΔS', and ΔSV, but higher TAPSE/PASP than men. Aging was associated with decreased ΔTAPSE/PASP, ΔTAPSE, ΔS', ΔPASP, and ΔSV. In addition, ΔS', ΔTAPSE/PASP, ΔPASP, and ΔSV, but not ΔTAPSE, were directly correlated with maximum workload. Conclusions: Our results provide age- and sex-related limits of normal for RV contractile reserve as assessed by exercise stress echocardiography and demonstrate that RV systolic function indices (PASP, TAPSE, S', and TAPSE/PASP) correlate with maximum exercise capacity., SCOPUS: ar.j, FLWIN, info:eu-repo/semantics/published

Aims A simple echocardiographic score was designed for diagnosing precapillary vs postcapillary pulmonary hypertension and for discriminating between isolated postcapillary pulmonary hypertension (Ipc-PH) and combined precapillary and postcapillary pulmonary hypertension (Cpc-PH). Methods The score comprised 7 points (2 for E/e0 ratio<-10, 2 for a dilated non-collapsible inferior vena cava, 1 for a left ventricular eccentricity index >-1.2, 1 for a right-to-left heart chamber dimension ratio >1 and 1 for the right ventricle forming the heart apex) and was applied to 230 consecutive patients referred for evaluation of pulmonary hypertension. Results Precapillary pulmonary hypertension and postcapillary pulmonary hypertension were diagnosed in 160 and 70 patients, respectively. In the latter, Ipc-PH was found in 51 and Cpc-PH in 19. The echo score was higher in precapillary vs postcapillary pulmonary hypertension patients (4.2 ± 1.7 vs 1.6 ± 1.7, P < 0.001) and in patients with Cpc-PH vs Ipc-PH (2.7 ± 2.1 vs 1.2 ± 1.3, P = 0.001). The sensitivity and specificity of the echo score at least 2 for precapillary pulmonary hypertension were 99 and 54%, respectively (area under the curve 0.85). In patients with postcapillary pulmonary hypertension, the sensitivity and specificity of the echo score at least 2 for Cpc-PH were 63 and 82% (area under the curve 0.73). Conclusion A simple echocardiographic score helps in the differential diagnosis between precapillary and postcapillary pulmonary hypertension, and between Ipc-PH and Cpc-PH., SCOPUS: ar.j, info:eu-repo/semantics/published

Background: The differential diagnosis between pre- and postcapillary pulmonary hypertension (PH) is of major therapeutic relevance and thus requires optimal clinical probability assessment with echocardiography. Methods: We prospectively analyzed 152 consecutive patients referred to a PH center over a 1-year period undergoing quasi-simultaneous (within 1 hour) echocardiography and right heart catheterization. Echocardiography was performed as usually recommended for the assessment of PH and left heart conditions. PH was defined as a mean pulmonary artery pressure >25 mm Hg. Postcapillary PH was diagnosed on the basis of a pulmonary capillary wedge pressure >15 mm Hg. Results: Ten of 152 patients (7%) had no PH, 81 of 152 (53%) had precapillary PH, and 61 of 152 (40%) had postcapillary PH. The following five echocardiographic variables were found to predict precapillary PH: right heart chamber larger than the left (P = .0018), left ventricular eccentricity index > 1.2 (P = .0039), dilated inferior vena cava without inspiratory collapse (P = .0076), E/e' ratio ≤10 (P = .00001), and the right ventricle forming the heart apex (P = .0144). Beta coefficients from multiple logistic regression were significant for dilated inferior vena cava without inspiratory collapse (P = .0464) and E/e' ratio ≤ 10 (P = .0002). The score based on b coefficients, ranging from 3 to 34 points, resulted in optimal discrimination at >5, with a positive predictive value of 67.9% and a negative predictive value of 77.5% for precapillary PH. Conclusion: Echocardiography enables a clinically satisfactory differential diagnosis between pre- and postcapillary PH., SCOPUS: ar.j, info:eu-repo/semantics/published

Tibetans have been reported to present with a unique phenotypic adaptation to high altitude characterized by higher resting ventilation (VE) and arterial oxygen saturation (SpO2), no excessive polycythemia and lower pulmonary artery pressures (Ppa) compared to other high altitude populations. How this affects exercise capacity is not exactly known. We measured aerobic exercise capacity during an incremental cardiopulmonary exercise test (CPET), lung diffusing capacity for carbon monoxide (DLCO) and nitric oxide (DLNO) at rest, and mean Ppa (mPpa) and cardiac output by echocardiography at rest and at exercise in 13 Sherpas and in 13 acclimatized lowlander controls at the altitude of 5050 m in Nepal. In Sherpas versus lowlanders, SpO2 was 86 ± 1 vs 83 ± 2 %, mean ± SE (P NS), mPpa at rest 19 ± 1 vs 23 ± 1 mmHg (P<0.05), DLCO corrected for hemoglobin 61 ± 4 vs 37 ± 2 ml/min/mmHg (P<0.001), DLNO 226 ± 18 vs 153 ± 9 ml/min/mmHg (P<0.001), maximum oxygen uptake (VO2max) 32 ± 3 vs 28 ± 1 ml/kg/min (P NS) and ventilatory equivalent for carbon dioxide at anaerobic threshold 40 ± 2 vs 48 ± 2 (P<0.001). VO2max was correlated directly to DLCO and inversely to the slope of mPpa-cardiac index relationships in both Sherpas and acclimatized lowlanders. We conclude that Sherpas compared to acclimatized lowlanders have an unremarkable aerobic exercise capacity but with less pronounced pulmonary hypertension, lower ventilatory responses and higher lung diffusing capacity., JOURNAL ARTICLE, SCOPUS: ar.j, info:eu-repo/semantics/published

It has been suggested that increased pulmonary vascular reserve, as defined by reduced pulmonary vascular resistance (PVR) and increased pulmonary transit of agitated contrast measured by echocardiography, might be associated with increased exercise capacity. Thus, at altitude, where PVR is increased because of hypoxic vasoconstriction, a reduced pulmonary vascular reserve could contribute to reduced exercise capacity. Furthermore, a lower PVR could be associated with higher capillary blood volume and an increased lung diffusing capacity. We reviewed echocardiographic estimates of PVR and measurements of lung diffusing capacity for nitric oxide (DL(NO)) and for carbon monoxide (DL(CO)) at rest, and incremental cardiopulmonary exercise tests in 64 healthy subjects at sea level and during 4 different medical expeditions at altitudes around 5000 m. Altitude exposure was associated with a decrease in maximum oxygen uptake (VO2max), from 42±10 to 32±8 mL/min/kg and increases in PVR, ventilatory equivalents for CO2 (V(E)/VCO2), DL(NO), and DL(CO). By univariate linear regression VO2max at sea level and at altitude was associated with V(E)/VCO2 (p<0.001), mean pulmonary artery pressure (mPpa, p<0.05), stroke volume index (SVI, p<0.05), DL(NO) (p<0.02), and DL(CO) (p=0.05). By multivariable analysis, VO2max at sea level and at altitude was associated with V(E)/VCO2, mPpa, SVI, and DL(NO). The multivariable analysis also showed that the altitude-related decrease in VO2max was associated with increased PVR and V(E)/VCO2. These results suggest that pulmonary vascular reserve, defined by a combination of decreased PVR and increased DL(NO), allows for superior aerobic exercise capacity at a lower ventilatory cost, at sea level and at high altitude., Journal Article, SCOPUS: ar.j, info:eu-repo/semantics/published

Journal Article, SCOPUS: le.j, info:eu-repo/semantics/published

info:eu-repo/semantics/published

Ce travail a été consacré à l’étude non invasive de la circulation pulmonaire normale par mise en œuvre de l’échocardiographie Doppler. En intégrant les mesures obtenues dans une approche physiopathologique, et en exploitant les nouvelles possibilités d’échocardiographes portables, techniquement performants, nous avons analysé les effets d’un inhibiteur de la phosphodiestérase-5 et d’une prostacycline, pour tenter d’en identifier d’éventuels effets introtropes intrinsèques, nous avons exploré le concept de réserve vasculaire pulmonaire comme facteur limitant de l’aptitude aérobie et indice potentiel d’une atteinte vasculaire pulmonaire précoce, et obtenu des résultats préliminaires permettant d’identifier une hypertension artérielle pulmonaire (HTAP) latente. Nos principaux résultats peuvent être résumés comme suit :1. Chez le sujet sain, en normoxie ou dans un modèle expérimental d’HTAP induite par l’inhalation d’un mélange gazeux hypoxique, le sildenafil per os ou l’epoprostenol par voie intraveineuse, à des doses utilisées en clinique pour le traitement de l’HTAP, améliorent les indices de la fonction ventriculaire droite en proportion de leurs effets vasodilatatoires pulmonaires, sans effets inotropes intrinsèques détectables.2. La consommation d’oxygène maximale du sujet sain augmente en raison directe de son volume capillaire pulmonaire (calculé à partir de sa capacité de diffusion pour l’oxyde nitrique et le monoxyde de carbone) et en raison inverse de sa résistance vasculaire pulmonaire, non seulement en altitude, mais aussi au niveau de la mer. Ce résultat suggère qu’une plus grande réserve vasculaire pulmonaire est propice aux efforts aérobiques intenses, probablement par moindre postcharge ventriculaire droite.3. Des mesures réalisées chez un petit nombre de sujets suggèrent que la distensibilité vasculaire pulmonaire, calculée à partir d’une relation débit-pression vasculaire pulmonaire, est typiquement réduite chez des porteurs asymptomatiqu, Doctorat en Sciences médicales, info:eu-repo/semantics/nonPublished

Doppler echocardiography plays a key role in the detection of pulmonary hypertension, the leading cause of right ventricular (RV) dysfunction. Reliable estimates of pulmonary pressures and cardiac output (CO) can be obtained at rest, allowing for screening and diagnosis of pulmonary arterial hypertension (PAH), a group of diseases characterized by increased pulmonary vascular resistance progressing to RV failure and death. However, these resting indices poorly correlate with symptoms, exercise response, and have modest prognosis significance. This is partially explained by the limited information obtained from pressure measurements on the severity of RV dysfunction, the major determinant of exercise response and prognosis in PAH. Exercise echocardiography (Ex-echo) may provide significant additional information in the understanding and the management of the disease. In asymptomatic subjects at risk of PAH, it may uncover abnormal increases in pulmonary pressure and CO during exercise, which may be reflecting early stage disease. In addition, the technique may be useful to better understand the physiology of exercise limitation, a typical manifestation of PAH. Several limitations need to be considered when using Ex-echo in the management of PAH, including the absence of a clear consistent definition of normal values, an unknown threshold for abnormal response and the limited quantitative information on RV function provided by simple pressure analysis. Newer echocardiographic techniques such as Tissue-Doppler imaging, and strain and strain rate analysis may provide further insights in the understanding of RV dysfunction. However, technical limitations currently prevent their application to Ex-echo. Clinical studies are underway to better explore the potential role of Ex-echo in the management of PAH. © The European Society of Cardiology 2007. All rights reserved., SCOPUS: ar.j, info:eu-repo/semantics/published

Right ventricular function is frequently abnormal in patients with systemic sclerosis, but whether this is related to pulmonary vascular complications of the disease is unclear. Standard echocardiography with tissue Doppler imaging was performed at rest and during exercise for the study of right ventricular function and pulmonary circulation in 25 consecutive systemic sclerosis patients and in 13 age-matched healthy controls. When compared with the controls, the patients had no difference in systolic right ventricular pressure gradient, but a decreased pulmonary flow acceleration time, and increased right ventricular free wall thickness and end-diastolic dimensions. At the tricuspid annulus, the E maximal velocity was decreased (8.9 +/- 4 versus 11.7 +/- 2.3 cm.s(-1)) and the isovolumic relaxation time corrected to RR interval was increased (6.5 +/- 2.9 versus 4.5 +/- 2.5%). The tissue Doppler imaging profile at the mitral annulus was similar in both groups. At exercise, 18 patients had a decreased maximum workload and cardiac output, no change in systolic right ventricular pressure gradient, but an increase in the slope of pulmonary artery pressure/flow relationships. These results suggest that patients with systemic sclerosis may present with latent pulmonary hypertension as a likely cause of right ventricular diastolic dysfunction, as revealed by stress echocardiography and tissue Doppler imaging., Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

SCOPUS: ar.j, info:eu-repo/semantics/published

Aerobic exercise capacity is decreased at altitude because of combined decreases in arterial oxygenation and in cardiac output. Hypoxic pulmonary vasoconstriction could limit cardiac output in hypoxia. We tested the hypothesis that acetazolamide could improve exercise capacity at altitude by an increased arterial oxygenation and an inhibition of hypoxic pulmonary vasoconstriction. Resting and exercise pulmonary artery pressure (Ppa) and flow (Q) (Doppler echocardiography) and exercise capacity (cardiopulmonary exercise test) were determined at sea level, 10 days after arrival on the Bolivian altiplano, at Huayna Potosi (4,700 m), and again after the intake of 250 mg acetazolamide vs. a placebo three times a day for 24 h. Acetazolamide and placebo were administered double-blind and in a random sequence. Altitude shifted Ppa/Q plots to higher pressures and decreased maximum O(2) consumption ((.)Vo(2max)). Acetazolamide had no effect on Ppa/Q plots but increased arterial O(2) saturation at rest from 84 +/- 5 to 90 +/- 3% (P < 0.05) and at exercise from 79 +/- 6 to 83 +/- 4% (P < 0.05), and O(2) consumption at the anaerobic threshold (V-slope method) from 21 +/- 5 to 25 +/- 5 ml.min(-1).kg(-1) (P < 0.01). However, acetazolamide did not affect (.)Vo(2max) (from 31 +/- 6 to 29 +/- 7 ml.kg(-1).min(-1)), and the maximum respiratory exchange ratio decreased from 1.2 +/- 0.06 to 1.05 +/- 0.03 (P < 0.001). We conclude that acetazolamide does not affect maximum exercise capacity or pulmonary hemodynamics at high altitudes. Associated changes in the respiratory exchange ratio may be due to altered CO(2) production kinetics., SCOPUS: ar.j, info:eu-repo/semantics/published

info:eu-repo/semantics/nonPublished