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It is unknown whether the availability of long drug-eluting stents modify the PCI strategy of long CTO. To describe the contemporary PCI strategy of long chronic total occlusions (CTO) using overlapping (OS) or single long stents (SS) and to analyze its results.2842 consecutive CTO PCIs were included. T hose with an occlusion length ≥20 mm in which ≥ 1 DES was implanted were analyzed. We compared procedural characteristics and clinical outcomes of CTO treated with OS or SS.1088 CTO PCIs were analyzed (79.9% males; 64.7±10.6 years). Mean J-score was 2.8 ± 0.9. A SS was used in 38.5% of cases and OS in 61.5%. Total stent length was 64.1±29.9 mm; it was higher in the OS group (OS:79.9±25.5 mm vs SS:38.3±14.7 mm; p0.0001). Mean number of stents in the OS group was 2.3±1. Very long stents (≥40 mm) were used in 27.4% of cases, more frequently in the OS group (OS:32.4% vs SS:19.3%; p0.0001). After a mean follow-up of 19±15.9 months, the rate of adverse events (MACE) was 2% (cardiac death:1.6%, myocardial infarction:1.6%, target lesion revascularization:1.9% and stent thrombosis: 0.18%) with no significant differences between both groups. Overlapping was not an independent predictor of MACE.In long CTO PCIs, OS is more frequently used than single stenting, especially in more complex procedures. Clinical outcomes at a mid-term follow-up are favorable. Using newer generation DES, overlapping was not an independent predictor of MACE, however a trend toward a higher event rate was observed in the OS group.

Objectives. The aim of this study is to assess the utility of optical coherence tomography (OCT) in patients with exercise-related acute coronary syndrome (ACS) presenting with inconclusive angiographic findings. Background. Regular physical activity reduces the incidence of cardiovascular events. Nevertheless, the risk of ACS or sudden cardiac death (SCD) increases during sport. In adults older than 35 years, exercise-related ACS or SCD is associated with plaque rupture, but not infrequently patients present ambiguous angiographic findings. Methods. Between September 2015 and January 2020, patients admitted for ACS or SCD triggered by physical exertion and with coronary stenosis ≤50% were included in this prospective observational study. OCT was performed on the artery deemed to be responsible of the event. Results. Ten patients were enrolled, predominantly men (80%) of middle age (51 years old, IQR 41–63) with low cardiovascular risk burden. Cycling was the most frequent (50%) exercise-related trigger, 8 patients were regular sport practitioners, and 7 had the clinical event during strenuous exertion. Five patients presented with non-ST-elevation ACS, two with ST-elevation ACS, and three with SCD. Angiographic analysis showed nonsignificant stenosis in all patients (42% stenosis, IQR 36–46). OCT identified the etiology of the event in 9 patients (4 plaque erosion, 3 plaque rupture, 1 eruptive calcific nodule, and 1 coronary dissection). Treatment was adjusted according to OCT findings. Conclusions. OCT is a valuable technique to identify the etiology of exercise-related ACS or SCD in patients with nonobstructive coronary arteries and, as a result, may lead to a more specific treatment.

Resumen Introduccion y objetivos El impacto de la intervencion coronaria percutanea (ICP) sobre oclusiones coronarias cronicas totales (OCT) presenta controversias. Se analizan los resultados agudos y al seguimiento en nuestro entorno. Metodos Registro prospectivo de ICP sobre OCT en 24 centros durante 2 anos. Resultados Se realizaron 1.000 ICP sobre OCT en 952 pacientes. La mayoria tenia sintomas (81,5%) y cardiopatia isquemica previa (59,2%), y hubo intentos de desobstruccion previos en un 15%. El SYNTAX anatomico fue 19,5 ± 10,6 y tenia J-score > 2 el 17,3%. El procedimiento fue retrogrado en 92 pacientes (9,2%). La tasa de exito fue del 74,9%, mayor en aquellos sin ICP previa (el 82,2 frente al 75,2%; p = 0,001), con J-score ≤ 2 (el 80,5 frente al 69,5%; p = 0,002) y con el uso de ecografia intravascular (el 89,9 frente al 76,2%; p = 0,001), que fue predictor independiente del exito. Por el contrario, lesiones calcificadas, > 20 mm o con munon proximal romo lo fueron de fracaso. El 7,1% tuvo complicaciones, como perforacion (3%), infarto (1,3%) o muerte (0,5%). Al ano de seguimiento, el 88,2% mejoro clinicamente en caso de ICP exitosa (frente al 34,8%; p Conclusiones Los pacientes del Registro Iberico con OCT tratados con ICP presentan complejidad clinico-anatomica, tasas de exito y complicaciones similares a los de otros registros nacionales e importante impacto de la recanalizacion exitosa en la mejoria funcional, que a su vez se asocio con menor mortalidad.

Aims: Current guidelines recommend an early invasive strategy in patients with non-ST-segment elevation acute coronary syndromes (NSTEACS). The role of an invasive strategy in frail elderly patients remains controversial. The aim of this substudy was to assess the impact of an invasive strategy on outcomes according to the degree of frailty in these patients. Methods and results: The LONGEVO-SCA registry included unselected NSTEACS patients aged =80 years. A geriatric assessment, including frailty, was performed during hospitalisation. During the admission, we evaluated the impact of an invasive strategy on the incidence of cardiac death, reinfarction or new revascularisation at six months. From 531 patients included, 145 (27.3%) were frail. Mean age was 84.3 years. Most patients underwent an invasive strategy (407/531, 76.6%). Patients undergoing an invasive strategy were younger and had a lower proportion of frailty (23.3% vs. 40.3%, p

Introduction and objectives: There is current controversy regarding the benefits of percutaneous recanalization (PCI) of chronic total coronary occlusions (CTO). Our aim was to determine acute and follow-up outcomes in our setting. Methods: Two-year prospective registry of consecutive patients undergoing PCI of CTO in 24 centers. Results: A total of 1000 PCIs of CTO were performed in 952 patients. Most were symptomatic (81.5%), with chronic ischemic heart disease (59.2%). Previous recanalization attempts had been made in 15%. The mean SYNTAX score was 19.5 +/- 10.6 and J-score was > 2 in 17.3%. A retrograde procedure was performed in 92 patients (9.2%). The success rate was 74.9% and was higher in patients without previous attempts (82.2% vs 75.2%; P = .001), those with a J-score 20 mm, and blunt proximal cap were independent predictors of failed recanalization. The rate of procedural complications was 7.1%, including perforation (3%), myocardial infarction (1.3%), and death (0.5%). At 1-year of follow-up, 88.2% of successfully revascularized patients showed clinical improvement (vs 34.8%, P < .001), which was associated with lower mortality. At 1-year of follow-up, the mortality rate was 1.5%. Conclusions: Compared with other national registries, patients in the Iberian registry undergoing PCI of a CTO showed similar complexity, success rate, and complications. Successful recanalization was strongly associated with functional improvement, which was related to lower mortality. (C) 2018 Published by Elsevier Espana, S.L.U. on behalf of Sociedad Espanola de Cardiologia.

The etiologic diagnosis of patients with myocardial infarction with nonobstructive coronary arteries (MINOCA) can be challenging. Optical coherence tomography (OCT) may play a role as a diagnostic tool. The aim of this study is to assess the usefulness of OCT to achieve an etiologic diagnosis in

Background: Information about the impact of frailty in patients with acute coronary syndromes (ACS) is scarce. No study has assessed the prognostic impact of frailty as measured by the FRAIL scale in very elderly patients with ACS. Methods: The prospective multicenter LONGEVO-SCA registry included unselected patients with ACS aged 80 years or older. A comprehensive geriatric assessment was performed during hospitalization, including frailty assessment by the FRAIL scale. The primary endpoint was mortality at 6 months. Results: A total of 532 patients were included. Mean age was 84.3 years, 61.7% male. Most patients had positive troponin levels (84%) and high GRACE risk score values (mean 165). A total of 205 patients were classified as prefrail (38.5%) and 145 as frail (27.3%). Frail and prefrail patients had a higher prevalence of comorbidities, lower left ventricle ejection fraction, and higher mean GRACE score value. A total of 63 patients (11.8%) were dead at 6 months. Both prefrailty and frailty were associated with higher 6-month mortality rates (P < .001). After adjusting for potential confounders, this association remained significant (hazard ratio [HR] 2.71; 95% confidence interval [CI] 1.09–6.73 for prefrailty and HR 2.99; 95% CI 1.20–7.44 for frailty, P = .024). The other independent predictors of mortality were age, Charlson Index, and GRACE risk score. Conclusions: The FRAIL scale is a simple tool that independently predicts mortality in unselected very elderly patients with ACS. The presence of prefrailty criteria also should be taken into account when performing risk stratification of these patients. Sin financiación 4.899 JCR (2018) Q1, 6/53 Geriatrics & Gerontology 2.123 SJR (2018) Q1, 2/152 Nursing (miscellaneous), 6/114 Geriatrics and Gerontology, 9/259 Health Policy, 139/2844 Medicine (miscellaneous) No data IDR 2018 UEM

Resumen Introduccion y objetivos La intervencion coronaria percutanea en pacientes con estenosis de tronco coronario izquierdo no protegido se recomienda en los casos que no son candidatos a cirugia de revascularizacion aortocoronaria. El seguimiento a largo plazo de estos pacientes continua siendo incierto. Metodos Se incluyo en el estudio a todos los pacientes consecutivos con un nuevo diagnostico de estenosis de tronco coronario izquierdo no protegido tratados con implantacion de stents. La indicacion de la intervencion coronaria percutanea se establecio segun los criterios de asistencia estandar, teniendo en cuenta las condiciones clinicas y anatomicas desfavorables para la utilizacion de la cirugia de revascularizacion aortocoronaria. El objetivo de valoracion principal es la aparicion de eventos cardiacos adversos mayores, incluidos los casos de muerte, infarto agudo de miocardio no mortal y revascularizacion de la lesion diana. Resultados Se incluyo en el analisis a un total de 226 pacientes consecutivos, de los que se trato a 202 (89,4%) con implantacion de stents liberadores de farmacos. La media de edad era 72,1 anos, el 41,1% de los pacientes tenian disfuncion renal y las medias de la puntuacion SYNTAX y del EuroSCORE fueron 28,9 y 7,4 respectivamente. Se alcanzo exito angiografico en el 99,6% de los pacientes y exito de la intervencion en el 92,9%. A los 3 anos, las tasas de eventos cardiacos adversos mayores, muerte, infarto agudo de miocardio no mortal y revascularizacion de la lesion diana fueron del 36,2, el 25,2, el 8,4 y el 8,0% respectivamente. La revascularizacion de la lesion diana se observo con mayor frecuencia en los casos en que se habian implantado ≥ 2 stents, en comparacion con los pacientes en quienes se habia utilizado un solo stent (el 18,5 frente al 5,8%; p = 0,03), asi como en los pacientes en quiens se utilizaron stents metalicos sin recubrimiento, en comparacion con los tratados con stents liberadores de farmacos (el 13,0% frente al 7,9%; p = 0,24). Se observo una trombosis de stent definitiva en 2 pacientes (0,9%) y una trombosis de stent probable en 7 (3,1%). El sexo femenino, el deterioro de la funcion del ventriculo izquierdo y el uso de stents sin recubrimiento mostraron una relacion significativa con la mortalidad por todas las causas. Conclusiones Los pacientes de alto riesgo con una estenosis de tronco coronario izquierdo no protegido tratados con una intervencion coronaria percutanea presentaron una tasa elevada de eventos cardiacos adversos mayores en el seguimiento a largo plazo. El sexo femenino, el deterioro de la funcion del ventriculo izquierdo y el uso de stents sin recubrimiento fueron factores predictivos de mal pronostico.

Introduccion y objetivos Evaluar el pronostico a largo plazo del dano miocardico producido durante el intervencionismo coronario percutaneo (ICP). Metodos Incluimos una serie de pacientes consecutivos a quienes se practico ICP, excluyendo a los que ya presentaban basalmente elevacion de marcadores cardiacos. El ECG y los marcadores de dano miocardico se evaluaron antes y a las 12 y 24 h tras el procedimiento. Segun el valor de dichos marcadores, se clasifico a los pacientes en tres grupos: ausencia de dano miocardico (troponina y CK-MB normal), dano miocardico minimo (elevacion del valor de troponina, con CK-MB normal) y mionecrosis (elevacion de troponina I y CK-MB). Muerte, infarto de miocardio y nueva revascularizacion fueron evaluados durante el seguimiento. Resultados De 757 pacientes incluidos, en 127 (16,8%) se detecto dano miocardico minimo asociado al procedimiento y en 46 (6,1%) mionecrosis. Durante un seguimiento de 45 ± 14 meses, 151 (19,1%) pacientes sufrieron eventos cardiacos. Los pacientes que presentaron mionecrosis tuvieron un significativo incremento de la mortalidad durante el seguimiento (13%) respecto a los otros dos grupos (el 4,8 y el 3,9%; log rank test, 6,83; p = 0,032). No se detectaron diferencias en la tasa de IAM o nueva revascularizacion en el seguimiento. Conclusiones El dano miocardico minimo durante el intervencionismo no influye en el pronostico a largo plazo. Por contra, la mionecrosis se asocia a un incremento de mortalidad. Este hecho implica la necesidad de determinar la CK-MB tras todo ICP debido a su implicacion pronostica y la aplicacion de estrategias que disminuyan la aparicion de mionecrosis.

Introduccion y objetivos En pacientes con un infarto agudo de miocardio con elevacion del ST tratado con trombolisis, se ha documentado una disfuncion endotelial precoz de la arteria que causa el infarto, asi como una mejoria de esta a largo plazo. Nuestro objetivo fue valorar el grado de disfuncion endotelial despues de una angioplastia primaria y en comparacion con la trombolisis. Metodos La funcion endotelial fue valorada 9 dias despues del infarto infundiendo acetilcolina a concentraciones crecientes y luego nitroglicerina en la arteria origen del infarto de 16 pacientes tratados con angioplastia primaria e implante de stent metalico. La funcion endotelial fue comparada con la de un grupo de 16 pacientes tratados con trombolisis en otro momento. Evaluamos los cambios edios en el diametro de los segmentos distales a la lesion causal o tratada, mediante angiografia coronaria cuantitativa. Resultados Las caracteristicas basales fueron similares en ambos grupos, a excepcion del tratamiento con clopidogrel en el grupo de angioplastia primaria y la estenosis residual de la arteria origen del infarto (del 3% en el grupo de angioplastia primaria frente al 62% del grupo de trombolisis). Con la concentracion maxima de acetilcolina, el grupo tratado con angioplastia primaria mostro menor vasoconstriccion que el grupo tratado con trombolisis (–4 ± 5% frente a -20 ± 21%; p = 0,018). Conclusiones Los pacientes con un infarto agudo de miocardio tratados con angioplastia primaria e implante de stent metalico tienen menor vasoconstriccion precoz dependiente del endotelio que los tratados con trombolisis.

Introduction and objectives. In patients with STelevation acute myocardial infarction treated by thrombolysis, both early endothelial dysfunction and longterm improvement in the infarct-related artery have been reported. Our aims were to assess the degree of endothelial dysfunction present after primary angioplasty and to compare it with that after thrombolysis. Methods. Endothelial function was assessed 9 days after infarction by infusing acetylcholine, at an increasing concentration, and subsequently nitroglycerine into the infarct-related artery in 16 patients who had undergone primary angioplasty and bare-metal stent implantation. In addition, endothelial function was compared with that in a group of 16 patients treated by thrombolysis in a different time period. The mean change in the diameters of segments distal to the culprit lesion or the treated lesion were evaluated by quantitative coronary angiography. Results. Baseline characteristics were similar in the 2 groups, except that patients in the primary angioplasty group were treated with clopidogrel and there were differences in residual stenosis in the infarct-related artery (3% in the primary angioplasty group compared with 62% in the thrombolysis group). At the maximum acetylcholine concentration, the degree of vasoconstriction was less in the primary angioplasty group than in the thrombolysis group (‐4[5]% vs. ‐20[21]%; P=.018). Conclusions. Early endothelium-dependent vasoconstriction in the infarct-related artery was lower in acute myocardial infarction patients treated by primary angioplasty and bare-metal stent implantation than in those treated by thrombolysis.

Los farmacos antitromboticos siguen teniendo un papel determinante en la realizacion del intervencionismo coronario percutaneo (ICP) debido a que, durante dichos procedimientos, el vaso tratado se expone a una situacion de un riesgo trombotico muy elevado. Sin embargo, el farmaco antitrombotico mas utilizado, la heparina, tiene una serie de limitaciones importantes. Los inhibidores directos de la trombina (IDT), por su mecanismo de interaccion directa con el centro activo de la molecula de trombina y debido a su efecto antiagregante plaquetario, ofrecen potenciales ventajas adicionales sobre la heparina. En un metaanalisis en el que se evaluaron la eficacia y la seguridad de los IDT en comparacion con la heparina en pacientes con sindromes coronarios agudos se documento que el tratamiento con IDT se asociaba con una reduccion significativa del 8% en la incidencia de muerte o infarto a los 30 dias, en comparacion con la heparina. La reduccion fue mas marcada en los pacientes en los que se realizo un ICP dentro de las primeras 72 h postaleatorizacion. Entre los distintos IDT, la bivalirudina es el farmaco sobre el que hay un volumen de informacion mas importante y consistente. El estudio REPLACE-2 definio el papel de la bivalirudina en pacientes con ICP. En dicho estudio se analizo de forma aleatorizada la eficacia de la bivalirudina y los inhibidores de los receptores de la glucoproteina (GP) IIb/IIIa con indicacion de rescate en comparacion con la heparina junto con la administracion sistematica de inhibidores de la GP IIb/IIIa. No se observaron diferencias significativas entre los 2 grupos de tratamiento para la variable principal combinada (el 10,0% en los pacientes asignados a heparina mas inhibidores de la GP IIb/IIIa y el 9,2% en los pacientes asignados a bivalirudina; p = NS) ni para la variable triple compuesta de eventos isquemicos (el 7,6 frente al 7,1%; p = NS). El estudio cumplio el criterio preespecificado de no inferioridad de la bivalirudina en comparacion con la administracion sistematica de heparina mas inhibidores de la GP IIb/IIIa. Un hallazgo consistente en todos los estudios realizados con bivalirudina es la reduccion en la incidencia de complicaciones hemorragicas en comparacion con los diferentes regimenes de heparina que han sido evaluados. En el estudio ACUITY, 13.819 pacientes con sindrome coronario agudo sin elevacion del segmento ST (SCASEST) de riesgo moderado o alto fueron aleatorizados a 3 grupos de tratamiento: a) heparina no fraccionada o de bajo peso molecular asociada sistematicamente con inhibidores de la GP IIb/IIIa; b) bivalirudina mas inhibidores de la GP IIb/IIIa tambien de forma sistematica, y c) bivalirudina aislada como monoterapia. Al analizar la incidencia de eventos clinicos compuestos a los 30 dias se documento una reduccion significativa en los pacientes asignados a monoterapia con bivalirudina en comparacion con los pacientes asignados a heparina mas inhibidores de la GP IIb/IIIa o bivalirudina mas inhibidores de la GP IIb/IIIa (el 10,1 frente al 11,8 frente al 11,7%, respectivamente; p En conclusion, teniendo en cuenta el similar grado de proteccion en la reduccion de eventos isquemicos y su reduccion en el riesgo hemorragico, la bivalirudina puede ser considerada como un tratamiento anticoagulante de eleccion en los pacientes con ICP en los que se contempla la administracion de heparina junto con inhibidores de la GP IIb/IIIa de forma sistematica. Asimismo, el beneficio clinico recientemente documentado de la bivalirudina en los pacientes con SCASEST tratados inicialmente de forma invasiva puede condicionar una modificacion en las estrategias actuales de actuacion y de tratamiento de estos pacientes.

We describe a single-center experience in using the Impella Recover LP 2.5 in the setting of high-risk elective percutaneous coronary interventions. This device is placed percutaneously to support cardiac output and has a better profile than other left ventricular assist devices. Our study shows that the use of the Impella Recover LP 2.5 device is feasible, has an overall favorable safety profile, and may help prevent periprocedural and short-term complications derived from high-risk procedures.

Introduction and objectives Percutaneous coronary intervention is recommended in patients with unprotected left main stenosis non suitable for coronary artery bypass graft. Long-term follow-up of those patients remains uncertain. Methods All patients with de novo unprotected left main stenosis treated with stent implantation were consecutively enrolled. Percutaneous coronary intervention was indicated according to the standards of care, taking into account clinical and anatomical conditions unfavorable for coronary artery bypass graft. The primary end point was the occurrence of major adverse cardiac events, a composite of death, nonfatal acute myocardial infarction, or target lesion revascularization. Results Of 226 consecutive patients included, 202 (89.4%) were treated with drug-eluting stents. Mean age was 72.1 years, 41.1% had renal dysfunction, and mean Syntax score and EuroSCORE were 28.9 and 7.4, respectively. Angiographic and procedural success was achieved in 99.6% and 92.9% of patients. At 3.0 years, the rates of major adverse cardiac events, death, nonfatal acute myocardial infarction and target lesion revascularization were 36.2%, 25.2%, 8.4%, 8.0%, respectively. Target lesion revascularization was more frequently observed when ≥2 stents were implanted rather than a single stent (18.5% vs 5.8%, P =.03); and with bare metal stents rather than drug-eluting stents (13.0% vs 7.9%, P =.24). Definite stent thrombosis was observed in 2 patients (0.9%) and probable stent thrombosis in 7 (3.1%). Female sex, impaired left ventricular function, and use of bare metal stents were significantly related with all-cause mortality. Conclusions High-risk patients with unprotected left main stenosis treated with percutaneous coronary intervention presented with a high rate of major adverse cardiac events at long-term follow-up. Female sex, impaired left ventricular function, and use of bare metal stents were predictors of poor prognosis.

To determine whether long-term prognosis is affected by myocardial damage taking place during percutaneous coronary intervention (PCI).The study included consecutive patients undergoing PCI. Those with elevated baseline cardiac marker levels were excluded. Cardiac markers were evaluated and an ECG was recorded before and 12 and 24 hours after PCI. Patients were divided into three groups after PCI according to their cardiac marker levels: no myocardial damage (i.e. normal troponin and creatine kinase MB fraction [CK-MB]), minor damage (elevated troponin with normal CK-MB), and myonecrosis (elevated troponin and CK-MB). The occurrence of death, myocardial infarction or repeat revascularization during follow-up was recorded.Minor myocardial damage associated with PCI was observed in 127 (16.8%) of the 757 patients included in the study and myonecrosis, in 46 (6.1%). During a follow-up of 45+/-14 months, cardiac events occurred in 151 (19.1%) patients. Mortality during follow-up was significantly higher in patients with myonecrosis (13%) than in the other two groups (4.8% and 3.9%; log rank, 6.83; P=.032). No difference was observed in the rate of myocardial infarction or repeat revascularization during follow-up.Minor myocardial damage during PCI had no effect on long-term prognosis. In contrast, myonecrosis was associated with increased mortality. Consequently, the CK-MB level should be measured after all PCIs because of its prognostic implications, and strategies for reducing the risk of myonecrosis developing should be implemented.

To identify the therapeutic regimens used at discharge in patients receiving oral anticoagulant therapy (OAT) who undergo stenting percutaneous coronary intervention and stent implantation (PCI-S), and to assess the safety and efficacy associated with different therapeutic regimens according to thromboembolic risk.A prospective multicentre registry.In hospital, after discharge and follow-up by telephone call.405 patients (328 male/77 female; mean (SD) age 71 (9) years) receiving OAT who underwent PCI-S between November 2003 and June 2006 from nine catheterisation laboratories of tertiary care teaching hospitals in Spain and one in the United Kingdom were included.Three therapeutic regimens were identified at discharge: triple therapy (TT) -- that is, any anticoagulant (AC) plus double antiplatelet therapy (DAT; 278 patients (68.6%); AC and a single antiplatelet (AC+AT; 46 (11.4%)) and DAT only (81 (20%)). At 6 months, patients receiving TT showed the greatest rate of bleeding events. No patients receiving DAT at low thromboembolic risk presented a bleeding event (14.8% receiving TT, 11.8% receiving AC+AT and 0% receiving DAT, p = 0.033) or cardiovascular event (6.7% receiving TT, 0% receiving AC+AT and 0% receiving DAT, p = 0.126). The combination of AC+AT showed the worst rate of adverse events in the whole cohort, especially in patients at moderate-high thromboembolic risk.In patients receiving OAT, TT was the most commonly used regimen after PCI-S. DAT was associated with the lowest rate of bleeding events and a similar efficacy to TT in patients at low thromboembolic risk. TT should probably be restricted to patients at moderate-high thromboembolic risk.

We examined the effects of the 5-phosphodiesterase (5-PDE) inhibitor sildenafil on pulmonary arterial pressure and some oxygen transport and cardiopulmonary parameters in humans during exposure to hypobaric hypoxia at rest and after exercise. In a double-blind study, 100 mg sildenafil or placebo was administered orally to 14 healthy volunteers 45 min before exposure to 5,000 m of simulated altitude. Arterial oxygen saturation (SaO2), heart rate (HR), tidal volume (VT), respiratory rate (RR), left ventricular ejection fraction (EF), and pulmonary arterial pressure (PAP) were measured first at rest in normoxia, at rest and immediately after exercise during hypoxia, and after exercise in normoxia. The increase in systolic PAP produced by hypoxia was significantly decreased by sildenafil at rest from 40.9 +/- 2.6 to 34.9 +/- 3.0 mmHg (-14.8%; p = 0.0046); after exercise, from 49.0 +/- 3.9 to 42.9 +/- 2.6 mmHg (-12.6%; p = 0.003). No significant changes were found in normoxia either at rest or after exercise. Measurements of the effect of sildenafil on exercise capacity during hypoxia did not provide conclusive data: a slight increase in SaO2 was observed with exercise during hypoxia, and sildenafil did not cause significant changes in ventilatory parameters under any condition. Sildenafil diminishes the pulmonary hypertension induced by acute exposure to hypobaric hypoxia at rest and after exercise. Further studies are needed to determine the benefit from this treatment and to further understand the effects of sildenafil on exercise capacity at altitude.