Pulmonary arterial wall disease in COPD and interstitial lung diseases candidates for lung transplantation.

BACKGROUND: Pulmonary hypertension (PH) associated with lung disease has the worst prognosis of all types of PH. Pulmonary arterial vasculopathy is an early event in the natural history of chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD). The present study characterized the alterations in the structure and function of the pulmonary arterial (PA) wall of COPD and ILD candidates for lung transplantation (LTx). METHODS: A cohort of 73 patients, 63 pre-LTx (30 COPD, 33 ILD), and ten controls underwent simultaneous right heart catheterisation and intravascular ultrasound (IVUS). Total pulmonary resistance (TPR), capacitance (Cp), and the TPR-Cp relationship were assessed. PA stiffness and the relative area of wall thickness were estimated as pulse PA pressure/IVUS pulsatility and as [(external sectional area-intimal area)/external sectional area] × 100, respectively. RESULTS: Twenty-seven percent of patients had pulmonary arterial wedge pressure > 15 mmHg and were not analyzed. PA stiffness and the area of wall thickness were increased in comparison with controls, even in patients without PH (p < 0.05). ILD patients showed a significant higher PA stiffness, and lower Cp beyond mean PA pressure (mPAP) and lower area of wall thickness than COPD patients (p < 0.05). TPR-Cp relationship was shifted downward left for ILD patients. CONCLUSIONS: Significant increase of PA stiffness and area of wall thickness were present even in patients without PH and can make the diagnosis of pulmonary vasculopathy at a preclinical stage in PH-lung disease candidates for LTx. ILD patients showed the worst PA stiffness and Cp with respect to COPD.

Pulmonary hypertension attenuates the dynamic preload indicators increase during experimental hypovolemia.

BACKGROUND: Pulse pressure (PPV) and stroke volume (SVV) variations may not be reliable in the setting of pulmonary hypertension and/or right ventricular (RV) failure. We hypothesized that RV afterload increase attenuates SVV and PPV during hypovolemia in a rabbit model of pulmonary embolism (PE) secondary to RV dysfunction. METHODS: Seven anesthetized and mechanically ventilated rabbits were studied during four experimental conditions: normovolemia, blood withdrawal, pulmonary embolism and fluid loading of a colloidal solution. Central venous, RV and left ventricular (LV) pressures, and infra-diaphragmatic aortic blood flow (AoF) and pressure were measured. SV was estimated by the integral of systolic AoF. We analyzed RV and LV function through stroke work output curves. PPV and SVV were obtained by the variation of beat-to-beat PP and SV, respectively. We assessed RV and LV diastolic and systolic function by the time rate of relaxation (tau) and the ratio of the first derivative of ventricular pressure and the highest isovolumic developed pressure (dP/dt/DP), respectively. The vasomotor tone was estimated by the dynamic arterial elastance (Eadyn = PPV/SVV). RESULTS: PPV and SVV increased significantly during hemorrhage and returned to baseline values after PE which was associated to biventricular right-downward of the stroke work curves and a decrease of AoF and SV (P < 0.05). RV systo-diastolic function and LV systolic function were impaired. All the animals were nonresponders after volume expansion. Eadyn did not show any significant change during the different experimental conditions. CONCLUSIONS: The dynamic preload indicators (SVV and PPV) were significantly reduced after a normotensive PE in hypovolemic animals, mainly by the systo-diastolic dysfunction of the RV associated with LV systolic impairment, which makes the animals nonresponsive to volume loading. This normalization of dynamic preload indices may prevent the detrimental consequence of fluid loading.

Impairment of pulmonary vascular reserve and right ventricular systolic reserve in pulmonary arterial hypertension.

BACKGROUND: Exercise capacity is impaired in pulmonary arterial hypertension (PAH). We hypothesized that cardiovascular reserve abnormalities would be associated with impaired hemodynamic response to pharmacological stress and worse outcome in PAH. METHODS: Eighteen PAH patients (p) group 1 NYHA class II/III and ten controls underwent simultaneous right cardiac catheterization and intravascular ultrasound at rest and during low dose-dobutamine (10 mcg/kg/min) with trendelenburg (DST). We estimated cardiac output (CO), pulmonary vascular resistance (PVR) and capacitance (PC), and PA elastic modulus (EM). We concomitantly measured tricuspid annular plane systolic excursion (TAPSE), RV myocardial peak systolic velocity (Sm) and isovolumic myocardial acceleration (IVA) in PAH patients. Based on the rounded mean + 2 SD of the increase in mPAP in our healthy control group during DST (2.8 + 1.8 mm Hg), PAH p were divided into two groups according to mean PA pressure (mPAP) response during DST, 1: ΔmPAP > 5 mm Hg and 2: ΔmPAP ≤ 5 mm Hg. Cardiovascular reserve was estimated as the change (delta, Δ) during DST compared with rest, including ΔmPAP with respect to ΔCO (ΔmPAP/ΔCO). All patients were prospectively followed up for 2 years. RESULTS: PAH p showed significant lower heart rate and CO increase than controls during DST, with a significant mPAP and pulse PAP increase and higher ΔmPAP/ΔCO (p < 0.05). Neither hemodynamic, IVUS and echocardiographic data were different between both PAH groups at rest. In group 1, DST caused a higher ΔEM, ΔmPAP/ΔCO, ΔPVR, and ΔTAPSE than group 2, with a lower IVA increase and a negative ΔSV (p < 0.05). TAPSE correlated with mPAP and RVP (p < 0.05) and, IVA and Sm correlated with CO (p < 0.05). ΔEM correlated with ΔmPAP and ΔIVA with ΔCO (p < 0.05). There were two deaths/pulmonary transplantations in group 1 and one death in group 2 during the follow-up (p > 0.05). CONCLUSIONS: Pulmonary vascular reserve and RV systolic reserve are significantly impaired in patients with PAH. The lower recruitable cardiovascular reserve is significantly related to a worse hemodynamic response to DST and it could be associated with a poor clinical outcome.

Pulmonary vascular pressure respiratory swings in COPD and ILD candidates for lung transplantation: Large but different.

We analyzed the effect of respiratory swings on interpreting intravascular pulmonary vascular pressures (PVPs) in chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) candidates for lung transplantation (LTx) and the role of the alterations in pulmonary function tests on the dynamic respiratory variations. Twenty-eight consecutive patients were included. All patients underwent a complete hemodynamic study (right atrial, mean pulmonary arterial, and pulmonary arterial occlusion pressures [RAP, mPAP, and PAOP]-) and pulmonary function testing (force vital capacity [FVC], forced expiratory volume in the first second [FEV1], and residual volume [RV]). A subgroup of 10 patients underwent simultaneous esophageal pressure (PES). All hemodynamic parameters and PES were collected during apnea after an unforced expiration (ee) and during spontaneous breathing averaging five respiratory cycles (mrc). The respiratory swing (osc) was estimated as the difference between maximum-minimum values of pressures during the respiratory cycle. Intravascular RAPee, mPAPee, and PAOPee were higher than mrc values (p < 0.05), leading to 11% of pulmonary hypertension (PH) misdiagnosis and 37% of postcapillary PH misclassification. PAOPosc of COPD was higher than ILD patients and RAPosc (p < 0.05). Only PAOPosc correlated with FVC, FEV1, and RV (p < 0.05). ILD PESmrc was lower than COPD (p < 0.05), and it was associated with a significantly higher transmural than intravascular RAPmrc, mPAPmrc, and PAOPmrc. PESmrc was significantly correlated with FVC. Transmural mPAPmrc and PAOPmrc readings determined around 20% of reclassification of the patients compared to ee measurements. Candidates for LTx showed large respiratory swings in PVP, which were correlated with pulmonary function alterations. mrc PVP would be more closely approximated to the true transmural PVP leading to PH reclassification. Adjusting PVP for PES should be considered in COPD and ILD candidates of LTx with severe alterations in pulmonary functional tests and suspicion of a PESmrc far from 0. PES respiratory swings could be different in ILD to COPD patients.

The increase of vasomotor tone avoids the ability of the dynamic preload indicators to estimate fluid responsiveness.

BACKGROUND: The use of vasoconstrictor can affect the dynamic indices to predict fluid responsiveness. We investigate the effects of an increase of vascular tone on dynamic variables of fluid responsiveness in a rabbit model of hemorrhage, and to examine the ability of the arterial pressure surrogates dynamic indices to track systolic volume variation (SVV) during hypovolemia under increased vasomotor tone. METHODS: Eighteen anesthetized and mechanically ventilated rabbits were studied during normovolemia (BL) and after blood progressive removal (15 mL/kg, BW). Other two sets of data were obtained during PHE infusion with normovolemia (BL + PHE) and during hypovolemia (BW + PHE). We measured central venous and left ventricular (LV) pressures and infra diaphragmatic aortic blood flow (AoF) and pressure. Pulse pressure variation (PPV), systolic pressure variation (SPV) and SVV were estimated manually by the variation of beat-to-beat PP, SP and SV, respectively. We also calculated PPVapnea as 100 × (PPmax-PPmin)/PP during apnea. The vasomotor tone was estimated by total peripheral resistance (TPR = mean aortic pressure/mean AoF), dynamic arterial elastance (Eadyn = PPV/SVV) and arterial compliance (C = SV/PP). We assessed LV preload by LV end-diastolic pressure (LVEDP). We compared the trending abilities between SVV and pressure surrogate indices using four-quadrant plots and polar plots. RESULTS: Baseline PPV, SPV, PPVapnea, and SVV increased significantly during hemorrhage, with a decrease of AoF (P < 0.05). PHE induced significant TPR and Eadyn increase and C decrease in bled animals, and a further decrease in AoF with a significant decrease of all dynamic indices. There was a significant correlation between SVV and PPV, PPVapnea and SPV in normal vasomotor tone (r2 ≥ 0.5). The concordance rate was 91%, 95% and 76% between SVV and PPV, PPVapnea and SPV, respectively, in accordance with the polar plot analysis. During PHE infusion, there was no correlation between SVV and its surrogates, and both four-quadrant plot and polar plot showed poor trending. CONCLUSION: In this animal model of hemorrhage and increased vasomotor tone induced by phenylephrine the ability of dynamic indices to predict fluid responsiveness seems to be impaired, masking the true fluid loss. Moreover, the arterial pressure surrogates have not the reliable trending ability against SVV.

Pulmonary Arterial Remodeling Is Related to the Risk Stratification and Right Ventricular-Pulmonary Arterial Coupling in Patients With Pulmonary Arterial Hypertension.

BACKGROUND: Pulmonary arterial (PA) stiffness has an essential contribution to the right ventricular (RV) failure pathogenesis. A comprehensive and multiparameter risk assessment allows predicting mortality and guiding treatment decisions in PA hypertension (PAH). We characterize PA remodeling with intravascular ultrasound (IVUS) in prevalent and stable patients with PAH according to the ESC/ERS risk table and analyze the RV-PA coupling consequences. METHODS: Ten control subjects and 20 prevalent PAH adult patients underwent right heart catheterization (RHC) with simultaneous IVUS study. We estimated cardiac index (CI), pulmonary vascular resistance, and compliance (PVR, PAC) by standard formulas. From IVUS and RHC data, PA diameter, wall thickness/luminal diameter ratio, and indexes of stiffness (pulsatility, compliance, distensibility, incremental elastic modulus - Einc-, and the stiffness index ß) were measured. We evaluated RV-PA coupling by the ratio of tricuspid annular plane systolic excursion to systolic pulmonary arterial pressure (TAPSE/sPAP). The individual average risk was calculated by assigning a score of 1 (low-risk -LR-), 2 (intermediate-risk -IR-), and 3 (high-risk -HR-) for each of seven variables (functional class, six-minute walking test, brain natriuretic peptide, right atrial area and pressure, CI, and PA oxygen saturation) and rounding the average value to the nearest integer. RESULTS: All PA segments interrogated showed increased vessel diameter, wall cross-sectional area (WCSA), and stiffness in patients with PAH compared to control subjects. 45% corresponded to LR, and 55% corresponded to IR PAH patients. The different measurements of PA stiffness showed significant correlations with TAPSE/sPAP (r = 0.6 to 0.76) in PAH patients. The IR group had higher PA stiffness and lower relative WCSA than LR patients (P < 0.05), and it is associated with a lower PAC and TAPSE/sPAP (P < 0.05). CONCLUSION: In prevalent PAH patients, the severity of proximal PA remodeling is related to the risk stratification and associated with PAC and RV-PA coupling impairment beyond the indirect effect of the mean PA pressure. The concomitant assessment of IVUS and hemodynamic parameters at diagnosis and follow-up of PAH patients could be a feasible and safe tool for risk stratification and treatment response of the PA vasculopathy during serial hemodynamic measurements.

End-Expiratory Occlusion Test During Increase of Vasomotor Tone in a Rabbit Model of Hemorrhage.

End-expiratory occlusion test (EEOT) has been proposed as a preload responsiveness test that overcomes several limitations of pulse pressure (PPV) and stroke volume (SVV) variations. We compared the ability of EEOT versus SVV and PPV to predict fluid responsiveness during the increase of the vasomotor tone in a rabbit model of hemorrhage. Ten rabbits were anesthetized, paralyzed, and mechanically ventilated during basal load (BL), after progressive blood withdrawal (BW), and after volume replacement. Other two sets of data were obtained during vasomotor increase by phenylephrine (PHE) infusion in BL and BW. We estimated the change of stroke volume (∆SVEEOT) and aortic flow (∆AoFEEOT) during the EEOT. PPV and SVV were obtained by the variation of beat-to-beat PP and SV, respectively. Baseline PPV, SVV, ∆SVEEOT, and ∆AoFEEOT increased significantly after BW, with a decrease of aortic flow (P < 0.05). PHE induced a significant decrease of PPV and SVV, but without affecting ∆SVEEOT, and ∆AoFEEOT. We conclude that ∆SV and ∆AoF during EEOT kept the ability to predict fluid responsiveness during PHE infusion in a rabbit hemorrhage model. This result may suggest the advantage of EEOT with respect to SVV and PPV in predicting fluid responsiveness during vasomotor tone increase.

Proximal pulmonary arterial wall disease in patients with persistent pulmonary hypertension after successful left-sided valve replacement according to the hemodynamic phenotype.

Regression of pulmonary hypertension (PH) is often incomplete after successful left-sided valve replacement (LSVR). Proximal pulmonary arterial (PPA) wall disease can be involved in patients with persistent-PH after LSVR, affecting the right ventricular to pulmonary arterial (RV-PA) coupling. Fifteen patients underwent successful LSVR at least one year ago presenting PH by echo (> 50 mmHg). Prosthesis-patient mismatch and left ventricular dysfunction were discarded. All patients underwent hemodynamic and intravascular ultrasound (IVUS) study. We estimated PPA stiffness (elastic modulus [EM]) and the relative area wall thickness (AWT). Acute vasoreactivity was assessed by inhaled nitric oxide (iNO) testing. RV-PA coupling was estimated by the tricuspid annular plane systolic excursion to systolic pulmonary arterial pressure ratio. Patients were classified as isolated post-capillary PH (Ipc-PH; pulmonary vascular resistance [PVR] ≤ 3 WU and/or diastolic pulmonary gradient [DPG] < 7 mmHg) and combined post- and pre-capillary PH (Cpc-PH; PVR > 3 WU and DPG ≥ 7 mmHg). Both Ipc-PH and Cpc-PH showed a significant increase of EM and AWT. Despite normal PVR and DPG, Ipc-PH had a significant decrease in pulmonary arterial capacitance and RV-PA coupling impairment. Cpc-PH had worse PA stiffness and RV-PA coupling to Ipc-PH ( P < 0.05). iNO decreased RV afterload, improving the cardiac index and stroke volume only in Cpc-PH ( P < 0.05). Patients with persistent PH after successful LSVR have PPA wall disease and RV-PA coupling impairment beyond the hemodynamic phenotype. Cpc-PH is responsive to iNO, having the worse PA stiffness and RV-PA coupling. The PPA remodeling could be an early event in the natural history of PH associated with left heart disease.

Acute Right Ventricular Dysfunction in Intensive Care Unit.

The role of the left ventricle in ICU patients with circulatory shock has long been considered. However, acute right ventricle (RV) dysfunction causes and aggravates many common critical diseases (acute respiratory distress syndrome, pulmonary embolism, acute myocardial infarction, and postoperative cardiac surgery). Several supportive therapies, including mechanical ventilation and fluid management, can make RV dysfunction worse, potentially exacerbating shock. We briefly review the epidemiology, pathophysiology, diagnosis, and recommendations to guide management of acute RV dysfunction in ICU patients. Our aim is to clarify the complex effects of mechanical ventilation, fluid therapy, vasoactive drug infusions, and other therapies to resuscitate the critical patient optimally.

Interrater Reliability and Diagnostic Performance of Subjective Evaluation of Sublingual Microcirculation Images by Physicians and Nurses: A Multicenter Observational Study.

INTRODUCTION: This was a cross-sectional multicenter study to investigate the ability of physicians and nurses from three different countries to subjectively evaluate sublingual microcirculation images and thereby discriminate normal from abnormal sublingual microcirculation based on flow and density abnormalities. METHODS: Forty-five physicians and 61 nurses (mean age, 36 ± 10 years; 44 males) from three different centers in The Netherlands (n = 61), Uruguay (n = 12), and Japan (n = 33) were asked to subjectively evaluate a sample of 15 microcirculation videos randomly selected from an experimental model of endotoxic shock in pigs. All videos were first analyzed offline using the A.V.A. software by an independent, experienced investigator and were categorized as good, bad, or very bad microcirculation based on the microvascular flow index, perfused capillary density, and proportion of perfused capillaries. Then, the videos were randomly assigned to the examiners, who were instructed to subjectively categorize each image as good, bad, or very bad. An interrater analysis was performed, and sensitivity and specificity tests were calculated to evaluate the proportion of A.V.A. score abnormalities that the examiners correctly identified. RESULTS: The κ statistics indicated moderate agreement in the evaluation of microcirculation abnormalities using three categories, i.e., good, bad, or very bad (κ = 0.48), and substantial agreement using two categories, i.e., normal (good) and abnormal (bad or very bad) (κ = 0.66). There was no significant difference between the κ three and κ two statistics. We found that the examiner's subjective evaluations had good diagnostic performance and were highly sensitive (84%; 95% confidence interval, 81%-86%) and specific (87%; 95% confidence interval, 84%-90%) for sublingual microcirculatory abnormalities as assessed using the A.V.A. software. CONCLUSIONS: The subjective evaluations of sublingual microcirculation by physicians and nurses agreed well with a conventional offline analysis and were highly sensitive and specific for sublingual microcirculatory abnormalities.

[Acute pulmonary hypertension: protective role of vascular smooth muscle activation]. / Hipertención pulmonar aguda: función protectora de la activación del músculo liso vascular.

AIM: To characterize the buffering function of the pulmonary artery in vivo and to determine the role of vascular smooth muscle (VSM) activation in vessel wall elasticity. MATERIAL AND METHOD: Pulmonary artery pressure and diameter were measured in 9 anesthetized sheep. Pulmonary artery hypertension was induced by mechanical occlusion of the pulmonary artery and by phenylephrine infusion (5 microg/kg/min) (PHE). Once the pressure-diameter loop was obtained, hysteresis was reduced to a minimum by increasing the modulus of viscosity. Elasticity was calculated as the first derivative of mean diastolic pressure assuming a purely elastic relation. Pulse wave velocity (PWV) and time constant (tau) were also obtained. RESULTS: Systolic, diastolic, mean and pulse pressures were similar during pulmonary artery hypertension and PHE infusion, but significantly higher in comparison to baseline conditions. Elasticity and diameter of the pulmonary artery increased significantly. In contrast, during VSM activation elasticity remained unchanged and diastolic diameter was reduced. PWV increased during both pulmonary artery hypertension and PHE infusion (p < 0.05); however, the increase during PHE infusion was smaller (15%) than during induced hypertension (33%). tau was significantly reduced during hypertension, but did not change during VSM activation. CONCLUSIONS: VSM activation may offset the deleterious effect of pulmonary artery hypertension on arterial wall stiffness by reducing elasticity and PWV. The VSM may modulate the Windkessel function in the pulmonary artery, preserving elasticity indexes during pulmonary artery hypertension.

[The vascular smooth muscle of great arteries: local control site of arterial buffering function?]. / El músculo liso vascular de las grandes arterias: ¿sitio de control local de la función de amortiguamiento arterial?

INTRODUCTION AND OBJECTIVES: To characterize the viscoelastic properties of the aorta and pulmonary arteries and the effects of vascular smooth muscle activation on arterial buffering function. MATERIAL AND METHOD: Aortic and pulmonary artery pressure and diameter were measured in six anesthetized sheep under baseline conditions, and during arterial hypertension induced by mechanical vascular occlusion (passive), and i.v. phenylephrine (active). Arterial wall elasticity and viscosity were calculated, and buffering function was characterized: a) locally as the viscosity/elasticity ratio, and b) globally for each circuit, as the time-constant of ventricular relaxation. RESULTS: Viscoelasticity was higher in the aorta than in the pulmonary artery (p < 0.05), however, parietal buffering function was similar in both. Global buffering function was highest in the systemic circuit (p < 0.05). During passive hypertension, elasticity was significantly increased with no change in viscosity; this led to a significant reduction in local buffering function, and in global buffering function in each circuit. During active hypertension, viscosity increased (p < 0.05), while local and global buffering functions returned to baseline values. CONCLUSIONS: The viscosity/elasticity ratio was higher in the aorta than in the pulmonary artery, and arterial wall buffering function was similar in both vessels. Systemic global buffering function was higher than pulmonary circuit buffering function. Elasticity depends on intravascular pressure, whereas viscosity is a marker of the degree of smooth muscle activation. Smooth muscle activation may benefit the cardiovascular system by maintaining local and global buffering functions.

Up-front combination therapy in pulmonary arterial hypertension: from clinical trials to 'real world' observational studies.

Combination therapy in pulmonary arterial hypertension is widely used in daily clinical practice. There is a wide variation among reference centers, with respect to not only when and how combination therapy should be initiated, but also what constitutes the most effective multidrug regimen. Presently, no combination therapy has proven to be more effective than the other. However, add-on therapy, in case of unsatisfactory improvements after initiation of specific monotherapy, seems to have more evidence of effectiveness than up-front therapy at the diagnosis. Data from national pulmonary arterial hypertension registries provide valuable information on practice patterns on diagnosis and treatment in 'real world'. In the study of Bergot et al. the current use of epoprostenol in newly diagnosed patients with severe idiopathic, heritable or anorexigen-use associated pulmonary arterial hypertension enrolled in the French pulmonary hypertension registry was investigated. Up-front combination of epoprostenol and oral pulmonary arterial hypertension tended to be more beneficial compared with epoprostenol alone. New drug trials with well-defined morbidity and mortality end-points are likely to help not only identify novel agents that may help in the treatment of pulmonary arterial hypertension but also determine the most useful combination strategies to maximize efficacy of existing drugs.

Diez años de experiencia de un centro de referencia en hipertensión arterial pulmonar en Uruguay / A ten year experience in a pulmonary hypertension reference center in Uruguay

Introducción: la hipertensión arterial pulmonar (HAP) es una condición clínica que conduce al fallo ventricular derecho y la muerte. Se caracterizó la epidemiología de pacientes con HAP en un centro de referencia de Uruguay. Métodos: se incluyeron 52 pacientes adultos con diagnóstico invasivo de HAP (enero 2006-diciembre 2016). Se estimó el riesgo mediante un modelo de cuatro variables (clase funcional-CF, distancia recorrida de 6 minutos -DR6M, presión auricular derecha e índice cardíaco). Se le asignó un valor de 1, 2 y 3 (bajo, intermedio y alto riesgo, respectivamente) a cada variable (European Society of Cardiology y European Respiratory Society 2015). Se categorizó el riesgo mediante el redondeo al valor entero más cercano del promedio de la suma de los valores asignados para cada variable. Resultados: edad 46±2 años, 85% femenino. Predominaron la HAP idiopática, HAP asociada a cardiopatía congénita (HAP-CPC) e HAP asociada a enfermedades del tejido conectivo (HAP-ETC). Los pacientes con HAP-CPC presentaron la mayor DR6M y la menor proporción de CF III/IV (p < 0,05). La sobrevida fue menor en HAP-ETC (p = 0,069). La mortalidad al año observada fue de 0%, 6% y 20% para pacientes con bajo (n=17), intermedio (n=28) y alto (n=7) riesgo, respectivamente, independientemente de la edad, sexo y subgrupo de HAP. El 51% de los pacientes con riesgo intermedio y alto recibieron tratamiento combinado. Conclusiones: se analizaron las características y sobrevida de pacientes con HAP de un centro de referencia uruguayo. El modelo de riesgo permitió discriminar la mortalidad de los pacientes. El 51% de los pacientes con riesgo intermedio y alto recibieron tratamiento combinado.

Introduction: Pulmonary Arterial Hypertension (PAH) is a clinical condition that leads to failure in the right ventricle and death. The epidemiology of patients with pulmonary hypertension was characterized in a reference center in Uruguay. Method: 52 patients with a diagnose of invasive pulmonary hypertension (January 2006-December 2016) were included in the study. Risk was estimated by means of a four variable model (functional class -FC, functional capacity, 6 minutes walking distance -6MWD, right atrium pressure and cardiac output). Values of 1, 2 and 3 were allocated (low, medium and high risk respectively) to each variable (ESC/ERS 2015 PAH guidelines). Risk was categorized by rounding the average of the sum of values allocated for each variable to the nearest integer. Results: age ranged 46±2 years old, 85% of patients were women. Idiopathic hypertension, PAH associated to congenital heart disease (PAH-CHD) and PAH associated to connective tissue diseases (PAH-CTD) prevailed. Patients with PAH-CHD evidenced the greatest 6MWD and the lowest proportion of FC III/IV (p <0.05). Survival was lowet in the PAH-CTD (p =0.069). Mortality after one year was 0%, 6% and 20% for patients with low (n=17), intermediate (n=28) and high (n=7) risk, respectively, regardless of age, sex and subgroup of PAH. 51% of patients with intermediate and high risk received combined treatment. Conclusions: the characteristics and survival of patients with PAH of a reference center in Uruguay were analysed in the study. The risk model allowed discriminating patient mortality. 51% of patients with intermediate and high risk received combined treatment.

Introdução: a Hipertensão Arterial Pulmonar (HAP) é uma condição clínica que leva a insuficiência ventricular direita e à morte. Neste artigo descreve-se a epidemiologia dos pacientes com HAP de um centro de referência no Uruguai. Métodos: foram incluídos 52 pacientes adultos com diagnóstico invasivo de HAP (janeiro 2006-dezembro 2016). O risco foi estimado utilizando um modelo com quatro variáveis (classe funcional -CF, distância percorrida em 6 minutos -DR6M, pressão auricular direita e índice cardíaco). Foram atribuídos os valores 1, 2 ou 3 (risco baixo, médio e alto respectivamente) a cada variável (ESC/ERS 2015). O risco foi caracterizado arredondando o valor inteiro mais próximo à média da soma dos valores atribuídos a cada variável. Resultados: a média de Idade dos pacientes era 46±2 anos sendo 85% do sexo feminino. Predominaram a HAP idiopática, a HAP associada a cardiopatia congênita (HAP-CPC) e HAP associada a doenças do tecido conectivo (HAP-ETC). Os pacientes com HAP-CPC apresentaram a maior DR6M e a menor proporção de CF III/IV (p <0.05). A sobrevida foi menor nos portadores de HAP-ETC (p =0.069). A mortalidade observada ao ano foi de 0%, 6% e 20% respectivamente para pacientes com risco baixo (n=17), médio (n=28) e alto (n=7), independentemente da idade, sexo e subgrupo de HAP. 51% dos pacientes com risco médio e alto receberam tratamento combinado. Conclusões: as características e a sobrevida de pacientes com HAP de um centro de referência uruguaio foram analisadas. O modelo de risco permitiu discriminar a mortalidade dos pacientes. 51% de dos pacientes com RI/RA recibieron tratamento combinado.

Pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension: How can patients be better selected?

Chronic thromboembolic pulmonary hypertension (CTEPH) comprises organizing thrombotic obstructions in the pulmonary arteries by nonresolving thromboemboli, formation of fibrosis and remodeling of pulmonary blood vessels. Surgical pulmonary endarterectomy (PEA) is the therapy of choice for patients with surgically accessible CTEPH, which leads to a profound improvement in hemodynamics, functional class and survival. Selecting the candidates that will benefit from surgery is still a challenging task. Criteria for surgical suitability have been described but the decision-making for or against surgical intervention remains still subjective. The optimal characterization of the reciprocal contribution of large vessel and small vessel disease in the elevation of pulmonary vascular resistance is crucial for the indication and outcome of PEA. Recently, Toshner et al intended to validate the partition resistance into small and large vessels compartments (upstream resistance: Rup) by the occlusion technique in the preoperative assessment of PEA. We discuss the advantages and disadvantages of Rup and compare it with other hemodynamic predictor to evaluate operative risk in CTEPH patients.