Pressure-volume loop validation of TAPSE/PASP for right ventricular arterial coupling in heart failure with pulmonary hypertension

Aims The aim of this study was to validate the tricuspid annular plane systolic excursion/systolic pulmonary artery (PA) pressure (TAPSE/PASP) ratio with the invasive pressure-volume (PV) loop-derived end-systolic right ventricular (RV) elastance/PA elastance (Ees/Ea) ratio in patients with heart failure with reduced ejection fraction (HFREF) and secondary pulmonary hypertension (PH).Methods and results The relationship of TAPSE and TAPSE/PASP with RV-PV loop (single-beat)-derived contractility Ees, afterload Ea, and Ees/Ea was assessed in 110 patients with HFREF with and without secondary PH. The results were compared with other surrogate parameters such as the fractional area change/PASP ratio. The association of the surrogates with all-cause mortality was evaluated. In patients with PH (n=74, 67%), TAPSE significantly correlated with Ees (r = 0.356), inverse with Ea (r = -0.514) but was most closely associated with Ees/Ea (r = 0.77). Placing TAPSE in a ratio with PASP slightly reduced the relationship to Ees/Ea (r = 0.71) but was more closely related to the parameters of PA vascular Load, diastolic RV function, and RV energetics. The area under the curve of TAPSE/PASP and TAPSE for discriminating overall survival in receiver operating characteristic analysis was not different (P = 0.78. Prognostic relevant cut-offs were 17mm for TAPSE and 0.38 mmimmHg for TAPSE/PASP. Both parameters in multivariate cox regression remained independently prognostically relevant.Conclusion TAPSE is an easily and reliably obtainable and valid surrogate parameter for RV-PA coupling in PH due to HFREF. Putting TAPSE into a ratio with PASP did not further improve the coupling information or prognostic assessment.Cardiolog

Predictors and prognosis of right ventricular function in pulmonary hypertension due to heart failure with reduced ejection fraction

Aims Failure of right ventricular (RV) function worsens outcome in pulmonary hypertension (PH). The adaptation of RV contractility to afterload, the RV-pulmonary artery (PA) coupling, is defined by the ratio of RV end-systolic to PA elastances (Ees/Ea). Using pressure-volume loop (PV-L) technique we aimed to identify an Ees/Ea cut-off predictive for overall survival and to assess hemodynamic and morphologic conditions for adapted RV function in secondary PH due to heart failure with reduced ejection fraction (HFREF).Methods and results This post hoc analysis is based on 112 patients of the prospective Magdeburger Resynchronization Responder Trial. All patients underwent right and left heart echocardiography and a baseline PV-L and RV catheter measurement. A subgroup of patients (n = 50) without a pre-implanted cardiac device underwent magnetic resonance imaging at baseline. The analysis revealed that 0.68 is an optimal Ees/Ea cut-off (area under the curve: 0.697, P = 0.68 vs. = 0.68 showed comparable RV-Ees/Ea ratios (0.88 vs. 0.9, P = 0.39), RV size/function, and survival. In contrast, secondary PH with RV-PA coupling ratio Ees/Ea 160 mL, RV-mass/volume-ratio 171 mL, odds ratio (OR) 0.96, P = 0.021], high pulsatile load (PA compliance = 0.68) in PH was associated with preserved RV size/function and mid-term survival, comparable with HFREF without PH.Cardiolog

Green leaf volatile emissions during high temperature and drought stress in a central Amazon rainforest

Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV) emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C5 and C6 GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C6 GLVs) were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress. © 2015 by the authors; licensee MDPI, Basel, Switzerland

Methanol and Isoprene Emissions from the Fast Growing Tropical Pioneer Species Vismia guianensis (Aubl.) Pers. (Hypericaceae) in the central Amazon Forest

Abstract. Isoprene (Is) emissions by plants represent a loss of carbon and energy resources leading to the initial hypothesis that fast growing pioneer species in secondary tropical forests allocate carbon primarily to growth at the expense of isoprenoid defenses. In this study, we quantified leaf isoprene and methanol emissions from the abundant pantropical pioneer tree species Vismia guianensis and ambient isoprene concentrations above a diverse secondary forest in the central Amazon. As photosynthetically active radiation (PAR) was varied (0 to 3,000 µmol m−2 s−1) under standard leaf temperature (30 °C), isoprene emissions from V. guianensis increased without saturation up to 80 nmol m−2 s−1. A non-linear increase in isoprene emissions with respect to net photosynthesis (Pn) resulted with the fraction of Pn dedicated to isoprene emissions increasing with light intensity (up to 2 % of Pn). Emission responses to temperature under standard light conditions (PAR of 1,000 µmol m−2 s−1) resulted in the classic uncoupling of isoprene emissions (Topt,iso > 40 ºC) from net photosynthesis (Topt, Pn = 30.0–32.5 °C) with up to 7 % of Pn emitted as isoprene at 40 °C. Under standard environmental conditions of PAR and leaf temperature, young V. guianensis leaves showed high methanol emissions, low Pn, and low isoprene emissions. In contrast, mature leaves showed high Pn, high isoprene emissions, and low methanol emissions, highlighting the differential control of leaf phenology over methanol and isoprene emissions. High daytime ambient isoprene concentrations (11 ppbv) were observed above a secondary Amazon rainforest suggesting that isoprene emissions are common among neotropical pioneer species. The results are not consistent with the initial hypothesis and support a functional role of methanol during leaf expansion and the establishment of photosynthetic machinery, and a protective role of isoprene for photosynthesis during high temperature extremes regularly experienced in secondary rainforest ecosystems

Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest

Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV) emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C5 and C6 GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C6 GLVs) were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress

Right heart function interacts with left ventricular remodeling after CRT: A pressure volume loop study

Cardiolog