Ten-year prognostic impact of target versus non-target vessel failure after STEMI. Insight from the EXAMINATION-EXTEND trial.

INTRODUCTION AND OBJECTIVES: After ST-segment myocardial infarction (STEMI), the impact of different adverse events on prognosis remains unknown. We aimed to assess very long-term predictors of patient-oriented composite endpoints (POCE) and investigate whether the occurrence of target vessel failure (TVF) vs a non-TVF event as the first event could potentially influence subsequent outcomes. METHODS: The EXAMINATION-EXTEND trial randomized STEMI patients to receive either an everolimus-eluting stent or a bare-metal stent. The follow-up period was 10 years. Predictors of POCE (a composite of all-cause death, any myocardial infarction, or any revascularization) were evaluated in the overall study population. The patients were stratified based on the type of first event (TVF-first vs non-TVF-first) and were compared in terms of subsequent POCE. TVF was defined as a composite of cardiac death, TV myocardial infarction, or TV revascularization. RESULTS: Out of the 1498 enrolled patients, 529 (35.3%) experienced a POCE during the 10-year follow-up. Independent predictors of POCE were age, diabetes mellitus, previous myocardial infarction, peripheral arterial disease, and multivessel coronary disease. The first event was a TVF in 296 patients and was a non-TVF in 233 patients. No significant differences were observed between TVF-first and non-TVF-first patients in terms of subsequent POCE (21.7% vs 39.3%, time ratio 1.79; 95%CI, 0.87-3.67;P=.12) or its individual components. CONCLUSIONS: At the 10-year follow-up, approximately one-third of STEMI patients had experienced at least 1 POCE. Independent predictors of these events were age, diabetes, and more extensive atherosclerotic disease. The occurrence of a TVF or a non-TVF as the first event did not seem to influence subsequent outcomes. TRIAL REGISTRATION NUMBER: NCT04462315.

Relationship between stent length and very long-term target lesion failure following percutaneous coronary intervention for ST-elevation myocardial infarction in the drug-eluting stents era: insights from the EXAMINATION-EXTEND study.

BACKGROUND: Little data exist on the relationship between total stent length (TSL) and cardiovascular outcomes at very-long follow-up in patients with ST-elevation myocardial infarction (STEMI) in the 2nd generation drug-eluting stents (DES) era. AIM: To analyze the relationship between TSL and 10-year target-lesion failure (TLF) in STEMI patients treated with percutaneous coronary intervention enrolled in the EXAMINATION-EXTEND. METHODS: The EXAMINATION-EXTEND was an extended-follow-up study of the EXAMINATION trial, which randomized 1:1 STEMI patients to receive DES or bare metal stent (BMS). The primary endpoint was TLF, defined as a composite of target lesion revascularization (TLR), target vessel myocardial infarction (TVMI), or definite/probable stent thrombosis (ST). Relationship between stent length and TLF was evaluated in the whole study group in a multiple-adjusted Cox regression model with TSL as a quantitative variable. Subgroup analysis was also performed according to stent type, diameter, and overlap. RESULTS: A total of 1,489 patients with a median TSL of 23 mm (Q1-Q318-35 mm) were included. TSL was associated with TLF at 10 years (adjusted HR per 5 mm increase of 1.07; 95% CI, 1.01-1.14; P = .02). This effect was mainly driven by TLR and was consistent regardless of stent type, diameter, or overlap. There was no significant relationship between TSL and TV-MI or ST. CONCLUSIONS: In STEMI patients, there is a direct relationship between TSL implanted in the culprit vessel and the risk of TLF at 10 years, mainly driven by TLR. The use of DES did not modify this association.

Overlapping versus single long stents in long chronic total occlusions: insights of the Iberian CTO Registry.

BACKGROUND: 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. METHODS: 2842 consecutive CTO PCIs were included. Those with an occlusion length ≥20 mm in which ≥1 drug eluting stent (DES) was implanted were analyzed. We compared procedural characteristics and clinical outcomes of CTO treated with OS or SS. RESULTS: 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; P<0.0001). 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%; P<0.0001). 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. CONCLUSIONS: 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.

Impact of Age at the Time of the First ST-Elevation Myocardial Infarction on 10-Year Outcomes (from the EXAMINATION-EXTEND Trial).

The aim of this substudy of the EXAMINATION-EXTEND was to analyze 10-year outcomes according to the patient's age at the time of the first ST-elevation myocardial infarction (STEMI). Of 1,498 patients with STEMI included in the EXAMINATION-EXTEND study, those with a previous history of coronary ischemic even or ischemic stroke were excluded from this analysis. The remaining 1,375 patients were divided into 4 age groups: <55, 55 to 65, 65 to 75, and >75 years. The primary end point was 10-year patient-oriented composite end point (POCE) of all-cause death, any MI, or any revascularization. At 10-year follow-up, patients aged <55 years (adjusted hazard ratio [HR] 0.24, 95% confidence interval [CI] 0.18 to 0.31, p = 0.001), 55 to 65 years (adjusted HR 0.26, 95% CI 0.20 to 0.34, p = 0.001), and 65 to 75 years (adjusted HR 0.38, 95% CI 0.30 to 0.50, p = 0.001) showed lower risk of POCE than those aged >75 years, led by a lower incidence of all-cause death (<55 : 6% vs 55 to 65: 11.9% vs 65 to 75: 25.7% vs >75 years: 61.6%, p = 0.001). Cardiac death was more prevalent in the older group (<55: 3.7% vs 55 to 65: 5.8% vs 65 to 75: 10.9% vs >75 years: 35.5%, p = 0.001). In the landmark analyses, between 5- and 10-year follow-up, young patients exhibited a higher incidence of any revascularization (<55: 7.4% vs 55 to 65: 4.9% vs 65 to 75: 1.8% vs >65 years: 1.6%, p = 0.001). In conclusion, in patients with a first STEMI, advanced age was associated with high rates of POCE at 10-year follow-up due to all-cause and cardiac death. Conversely, younger patients exhibited a high risk of revascularization at long-term follow-up.

Impact of Diabetes on 10-Year Outcomes Following ST-Segment-Elevation Myocardial Infarction: Insights From the EXAMINATION-EXTEND Trial.

Background Long-term outcomes of ST-segment-elevation myocardial infarction in patients with diabetes have been barely investigated. The objective of this analysis from the EXAMINATION-EXTEND (10-Years Follow-Up of the EXAMINATION trial) trial was to compare 10-year outcomes of patients with ST-segment-elevation myocardial infarction with and without diabetes. Methods and Results Of the study population, 258 patients had diabetes and 1240 did not. The primary end point was patient-oriented composite end point of all-cause death, any myocardial infarction, or any revascularization. Secondary end points were the individual components of the primary combined end point, cardiac death, target vessel myocardial infarction, target lesion revascularization, and stent thrombosis. All end points were adjusted for potential confounders. At 10 years, patients with diabetes showed a higher incidence of patient-oriented composite end point compared with those without (46.5% versus 33.0%; adjusted hazard ratio [HR], 1.31 [95% CI, 1.05-1.61]; P=0.016) mainly driven by a higher incidence of any revascularization (24.4% versus 16.6%; adjusted HR, 1.61 [95% CI, 1.19-2.17]; P=0.002). Specifically, patients with diabetes had a higher incidence of any revascularization during the first 5 years of follow-up (20.2% versus 12.8%; adjusted HR, 1.57 [95% CI, 1.13-2.19]; P=0.007) compared with those without diabetes. No statistically significant differences were found with respect to the other end points. Conclusions Patients with ST-segment-elevation myocardial infarction who had diabetes had worse clinical outcome at 10 years compared with those without diabetes, mainly driven by a higher incidence of any revascularizations in the first 5 years. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04462315.

Ruptured sinus of Valsalva aneurysm: A reversible cause of suprasystemic pulmonary hypertension.

Management of patients with congenital heart defects and associated pulmonary arterial hypertension remains a major concern. With evolving targeted drug therapies and new iterations of transcatheter devices, treatment of appropriately selected patients with severe pulmonary hypertension, classically considered inoperable, has become feasible. We report the case of a patient with concomitant ruptured right sinus of Valsalva aneurysm and ventricular septal defect, with early reversal of suprasystemic pulmonary pressures following successful percutaneous closure of ruptured sinus of Valsalva.

Sex Differences in 10-Year Outcomes Following STEMI: A Subanalysis From the EXAMINATION-EXTEND Trial.

BACKGROUND: Short-term outcomes following ST-segment elevation myocardial infarction (STEMI) in women are worse than in men, with a higher mortality rate. It is unknown whether sex plays a role in very long term outcomes. OBJECTIVES: The aim of this study was to assess whether very long term outcomes following STEMI treatment are influenced by sex. METHODS: EXAMINATION-EXTEND (10-Year Follow-Up of the EXAMINATION Trial) was an investigator-driven 10-year follow-up of the EXAMINATION (A Clinical Evaluation of Everolimus Eluting Coronary Stents in the Treatment of Patients With ST-Segment Elevation Myocardial Infarction) trial, which randomly 1:1 assigned 1,498 patients with STEMI to receive either everolimus-eluting stents or bare-metal stents. The present study was a subanalysis according to sex. The primary endpoint was the composite patient-oriented endpoint (all-cause death, any myocardial infarction, or any revascularization) at 10 years. Secondary endpoints were individual components of the primary endpoint. All endpoints were adjusted for age. RESULTS: Among 1,498 patients with STEMI, 254 (17%) were women. Overall, women were older, with more arterial hypertension and less smoking history than men. At 10 years, no difference was observed between women and men for the patient-oriented composite endpoint (40.6% vs 34.2%; adjusted HR: 1.14; 95% CI: 0.91-1.42; P = 0.259). There was a trend toward higher all-cause death in women vs men (27.6% vs 19.4%; adjusted HR: 1.30; 95% CI: 0.99-1.71; P = 0.063), with no difference in cardiac death or other endpoints. CONCLUSIONS: At very long term follow-up, there were no differences in the combined patient-oriented endpoint between women and men, with a trend toward higher all-cause death in women not driven by cardiac death. The present findings underline the need for focused personalized medicine in women after percutaneous revascularization aimed at both cardiovascular and sex-specific risk factor control and targeted treatment. (10-Years Follow-Up of the EXAMINATION Trial [EXAMINAT10N]; NCT04462315).

10-Year Follow-Up of Patients With Everolimus-Eluting Versus Bare-Metal Stents After ST-Segment Elevation Myocardial Infarction.

BACKGROUND: Outcomes data for a durable-polymer everolimus-eluting stent (EES) at extended long-term follow-up in patients with ST-segment elevation myocardial infarction (STEMI) are unknown. OBJECTIVES: The aim of this study was to assess the 10-year outcomes of patients enrolled in the EXAMINATION (A Clinical Evaluation of Everolimus Eluting Coronary Stents in the Treatment of Patients With ST-Segment Elevation Myocardial Infarction) trial. METHODS: The EXAMINATION-EXTEND (10-Years Follow-Up of the EXAMINATION Trial) study is an investigator-driven 10-year follow-up of the EXAMINATION trial, which randomly assigned 1,498 patients with STEMI in a 1:1 ratio to receive either EES (n = 751) or bare-metal stents (n = 747). The primary endpoint was a patient-oriented composite endpoint of all-cause death, any myocardial infarction, or any revascularization. Secondary endpoints included a device-oriented composite endpoint of cardiac death, target vessel myocardial infarction, or target lesion revascularization; the individual components of the combined endpoints; and stent thrombosis. RESULTS: Complete 10-year clinical follow-up was obtained in 94.5% of the EES group and 95.9% of the bare-metal stent group. Rates of the patient-oriented composite endpoint and device-oriented composite endpoint were significantly reduced in the EES group (32.4% vs. 38.0% [hazard ratio: 0.81; 95% confidence interval: 0.68 to 0.96; p = 0.013] and 13.6% vs. 18.4% [hazard ratio: 0.72; 95% confidence interval: 0.55 to 0.93; p = 0.012], respectively), driven mainly by target lesion revascularization (5.7% vs. 8.8%; p = 0.018). The rate of definite stent thrombosis was similar in both groups (2.2% vs. 2.5%; p = 0.590). No differences were found between the groups in terms of target lesion revascularization (1.4% vs. 1.3%; p = 0.963) and definite or probable stent thrombosis (0.6% vs. 0.4%; p = 0.703) between 5 and 10 years. CONCLUSIONS: At 10-year follow-up, EES demonstrated confirmed superiority in combined patient- and device-oriented composite endpoints compared with bare-metal stents in patients with STEMI requiring primary percutaneous coronary intervention. Between 5- and 10-year follow-up, a low incidence of adverse cardiovascular events related to device failure was found in both groups. (10-Years Follow-Up of the EXAMINATION Trial; NCT04462315).

Optical Coherence Tomography for the Diagnosis of Exercise-Related Acute Cardiovascular Events and Inconclusive Coronary Angiography.

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.

Procedural, Functional and Prognostic Outcomes Following Recanalization of Coronary Chronic Total Occlusions. Results of the Iberian Registry.

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 ≤ 2 (80.5% vs 69.5%; P = .002), and in intravascular ultrasound-guided PCI (89.9% vs 76.2%, P = .001), which was an independent predictor of success. In contrast, severe calcification, length > 20mm, 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.

Invasive strategy and frailty in very elderly patients with acute coronary syndromes.

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<0.001). The incidence of cardiac events was more common in patients managed conservatively, after adjusting for confounding factors (sub-hazard ratio [sHR] 2.32, 95% confidence interval [CI]: 1.26-4.29, p=0.007). This association remained significant in non-frail patients (sHR 3.85, 95% CI: 2.13-6.95, p=0.001), but was not significant in patients with established frailty criteria (sHR 1.40, 95% CI: 0.72-2.75, p=0.325). The interaction invasive strategy-frailty was significant (p=0.032). CONCLUSIONS: An invasive strategy was independently associated with better outcomes in very elderly patients with NSTEACS. This association was different according to frailty status.

Long-term follow-up after percutaneous treatment of the unprotected left main stenosis in high risk patients not suitable for bypass surgery.

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 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.

Use of Impella Recover LP 2.5 in elective high risk percutaneous coronary intervention.

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.

Minor myocardial damage during percutaneous coronary intervention does not affect long-term prognosis.

INTRODUCTION AND OBJECTIVES: To determine whether long-term prognosis is affected by myocardial damage taking place during percutaneous coronary intervention (PCI). METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Endothelial-dependent vasoconstriction in the infarct-related artery early after myocardial infarction is smaller following primary angioplasty than thrombolytic therapy.

INTRODUCTION AND OBJECTIVES: In patients with ST-elevation acute myocardial infarction treated by thrombolysis, both early endothelial dysfunction and long-term 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 two 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.

Effects of sildenafil on the human response to acute hypoxia and exercise.

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.