Effect Of Phosphodiesterase-5 Inhibition Research Articles

Prognostic Value and Determinants of High-Sensitivity Cardiac Troponin T in Patients With a Systemic Right Ventricle: Insights From the SERVE Trial.

The determinants and prognostic value of high-sensitivity cardiac troponin T (hs-cTnT) among patients with a systemic right ventricle are largely unknown. Ninety-eight patients from the randomized controlled SERVE (Effect of Phosphodiesterase-5 Inhibition With Tadalafil on Systemic Right Ventricular Size and Function) trial were included. The correlation between baseline hs-cTnT concentrations and biventricular volumes and function quantified by cardiac magnetic resonance or cardiac multirow detector computed tomography was assessed by adjusted linear regression models. The prognostic value of hs-cTnT was assessed by adjusted Cox proportional hazards models, survival analysis, and concordance statistics. The primary outcome was time to the composite of clinically relevant arrhythmia, hospitalization for heart failure, or all-cause death. Median age was 39 (interquartile range, 32-48) years, and 32% were women. Median hs-cTnT concentration was 7 (interquartile range, 4-11) ng/L. Coefficients of determination for the relationship between hs-cTnT concentrations and right ventricular end-systolic volume index and right ventricular ejection fraction (RVEF) were +0.368 (P=0.046) and -0.381 (P=0.018), respectively. The sex- and age-adjusted hazard ratio for the primary outcome of hs-cTnT at 2 and 4 times the reference level (5 ng/L) were 2.89 (95% CI, 1.14-7.29) and 4.42 (95% CI, 1.21-16.15), respectively. The prognostic performance quantified by the concordance statistics for age- and sex-adjusted models based on hs-cTnT, right ventricular ejection fraction, and peak oxygen uptake predicted were comparable: 0.71% (95% CI, 0.61-0.82), 0.72% (95% CI, 0.59-0.84), and 0.71% (95% CI, 0.59-0.83), respectively. Hs-cTnT concentration was significantly correlated with right ventricular ejection fraction and right ventricular end-systolic volume index in patients with a systemic right ventricle. The prognostic accuracy of hs-cTnT was comparable to that of right ventricular ejection fraction and peak oxygen uptake predicted. URL: https://www.clinicaltrials.gov; Unique identifier: NCT03049540.

Effect of phosphodiesterase-5 inhibition on SystEmic Right VEntricular size and function - A multicentre, double-blind, randomized, placebo-controlled trial - SERVE.

In adults with congenital heart disease and systemic right ventricles, progressive right ventricular systolic dysfunction is common and is associated with adverse outcomes. Our aim was to assess the impact of the phosphodiesterase-5-inhibitor tadalafil on right ventricular systolic function. This was a double-blind, randomized, placebo-controlled, multicentre superiority trial (NCT03049540) involving 100 adults with systemic right ventricles (33 women, mean age: 40.7 ± 10.7 years), comparing tadalafil 20 mg once daily versus placebo (1:1 ratio). The primary endpoint was the change in right ventricular end-systolic volume after 3 years of therapy. Secondary endpoints were changes in right ventricular ejection fraction, exercise capacity and N-terminal pro-B-type natriuretic peptide concentration. Primary endpoint assessment by intention to treat analysis at 3 years of follow-up was possible in 83 patients (42 patients in the tadalafil group and 41 patients in the placebo group). No significant changes over time in right ventricular end-systolic volumes were observed in the tadalafil and the placebo group, and no significant differences between treatment groups (3.4 ml, 95% confidence interval -4.3 to 11.0, p = 0.39). No significant changes over time were observed for the pre-specified secondary endpoints for the entire study population, without differences between the tadalafil and the placebo group. In this trial in adults with systemic right ventricles, right ventricular systolic function, exercise capacity and neuro-hormonal activation remained stable over a 3-year follow-up period. No significant treatment effect of tadalafil was observed. Further research is needed to find effective treatment for improvement of ventricular function in adults with systemic right ventricles.

Phenotypical Effect of Phosphodiesterase 5 (PDE5) Inhibitor on Behavioral Activities of Fruit Fly Drosophila melanogaster

Phosphodiesterase 5 (PDE5) inhibitor is a class of drugs currently used to treat erectile dysfunction. Physiologically, inhibition of PDE5 may lead to vasodilation, blood flow increment, and penile erection. However, PDE5 inhibitors have been reported not only to modify the function of the male reproductive organ but also to influence other physiological systems. To explore the effect of PDE5 inhibitor on metazoan physiological systems, a fruit fly (Drosophila melanogaster) model organism is used since the catalytic domain of fruit fly PDE5/6 shares a high similarity of amino acid sequence (58%) with the PDE5 of humans. This study aimed to investigate whether the effect of PDE5 inhibition by sildenafil is phenotypically observable as changes in the behavioral states. Two behavioral phenotypes of D. melanogaster, negative geotaxis, and ethanol sensitivity, were used as test parameters in this explorative study. The results demonstrated that sildenafil had a significant effect on reducing locomotor activity, as reflected by negative geotaxis assay, but it had no influence on the fruit fly sensitivity to ethanol. Taken together, our results suggested that PDE5 inhibition might impair the physiological condition of the metazoan species. Also, an explorative study using D. melanogaster might offer valuable insight as a model organism in the discovery and repurposing approach of PDE5 inhibitor.

Differential impact of severe familial hypercholesterolemia on regional skeletal muscle and organ blood flows during exercise: effects of PDE5 inhibition

Swine with familial hypercholesterolemia (FH) exhibit attenuated exercise‐induced systemic vasodilation that is restored by phosphodiesterase 5 (PDE5) inhibition. Whether the impacts of FH and PDE5 inhibition to impair and restore, respectively, exercise‐induced vasodilation results from tissue‐specific or generalized effects remains unclear. Thus, we hypothesized that FH induces generalized impairment of skeletal muscle vasodilation that would be alleviated by PDE5 inhibition. Systemic vascular responses to exercise were assessed in chronically instrumented normal and FH swine before and after PDE5 inhibition with EMD360527. Skeletal muscle and organ blood flows and conductances were determined via the microsphere technique. As previously reported, versus normal swine, FH swine have pronounced elevation of total cholesterol and impaired exercise‐induced vasodilation that is restored by PDE5 inhibition. Blood flows to several, not all, skeletal muscle vascular beds were severely impaired by FH associated with reduced blood flow to many visceral organs. PDE5 inhibition differentially impacted skeletal muscle and organ blood flows in normal and FH swine. These data indicate that FH induces regional, not generalized, vasomotor dysfunction and that FH and normal swine exhibit unique tissue blood flow responses to PDE5 inhibition thereby adding to accumulating evidence of vascular bed‐specific dysfunction in co‐morbid conditions.Support or Funding InformationSupported by NIH (HL52490 to MHL, HL136386 to SBB), The Netherlands Cardio Vascular Research Initiative, an initiative with support of the Dutch Heart Foundation (CVON2014‐11, RECONNECT to DM and DJD), and the Department of Veterans Affairs BLR&D (CDA‐2 IK2 BX002030 to SBB).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effect of phosphodiesterase-5 inhibition on joint and muscle damage in rats with adjuvant arthritis

Background/aim: This study was designed to examine the effect of tadalafil, a phosphodiesterase (PDE)5 inhibitor, on the severity of joint and muscle damage in rats with adjuvant-induced arthritis (AA). Materials and methods: AA was induced by intradermal inoculation into right hind paw of male Sprague Dawley rats (300-450g) with complete Freund's adjuvant (CFA; 0.1 mL). AA rats were treated with either tadalafil (10 mg/kg; per oral) alone or along with the soluble guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 mg/kg; intraperitoneally). After decapitation on day 16, trunk blood was collected for total oxidant status (TOS) and total antioxidant capacity (TAC) assays. The left metatarsophalangeal joint and gastrocnemius muscle were excised for microscopic examination. Muscle samples were also evaluated in terms of malondialdehyde (MDA), glutathione, and chemiluminescence (CL) levels. Results: In tadalafil-treated AA rats, metatarsophalangeal joints revealed regular morphology of the cartilage with slight destruction and less inflammatory cell infiltration and vascularization in comparison to the controls (microscopic score: 1.17 ± 0.31 vs. 4.17 ± 0.79; P < 0.01). AA rats presented increased gastrocnemius muscle MDA, glutathione, and CL levels compared to the controls (P < 0.01, for MDA; P < 0.05, for glutathione; P < 0.05 for CL). Tadalafil attenuated the increase in CL levels (P < 0.01, for luminol and P < 0.001, for lucigenin). Serum TOS showed significant reductions by tadalafil. Conclusion: The long-acting PDE5 inhibitor tadalafil provides partial protection in a rat model of CFA-induced arthritis possibly via suppression of oxidant generation.

Exercise training improves blood flow to contracting skeletal muscle of older men via enhanced cGMP signaling

Physical activity has the potential to offset age-related impairments in the regulation of blood flow and O2 delivery to the exercising muscles; however, the mechanisms underlying this effect of physical activity remain poorly understood. The present study examined the role of cGMP in training-induced adaptations in the regulation of skeletal muscle blood flow and oxidative metabolism during exercise in aging humans. We measured leg hemodynamics and oxidative metabolism during exercise engaging the knee extensor muscles in young [ n = 15, 25 ± 1 (SE) yr] and older ( n = 15, 72 ± 1 yr) subjects before and after a period of aerobic high-intensity exercise training. To determine the role of cGMP signaling, pharmacological inhibition of phosphodiesterase 5 (PDE5) was performed. Before training, inhibition of PDE5 increased ( P < 0.05) skeletal muscle blood flow and O2 uptake during moderate-intensity exercise in the older group; however, these effects of PDE5 inhibition were not detected after training. These findings suggest a role for enhanced cGMP signaling in the training-induced improvement of regulation of blood flow in contracting skeletal muscle of older men. NEW & NOTEWORTHY The present study provides evidence for enhanced cyclic GMP signaling playing an essential role in the improved regulation of blood flow in contracting skeletal muscle of older men with aerobic exercise training.

Effect of phosphodiesterase-5 inhibition with Tadalafil on SystEmic Right VEntricular size and function – A multi-center, double-blind, randomized, placebo-controlled clinical trial – SERVE trial - Rational and design

BackgroundPatients with a systemic right ventricle (RV) have a compromised late outcome caused by ventricular dysfunction. Standard medical heart failure therapy has not been shown to improve RV function and survival in these patients. Phosphodiesterase (PDE)-5 inhibition increases contractility in experimental models of RV hypertrophy, but not in the normal RV. In clinical practice, the effects of PDE-5 inhibition on systemic RV function and exercise capacity in adults with a systemic RV have not been tested. MethodsThe SERVE protocol is a double-blind, randomized placebo-controlled multicenter superiority trial to study the effect of PDE-5 inhibition with Tadalafil on RV volumes and function in patients with either D-transposition of the great arteries repaired with an atrial switch procedure or with congenitally corrected transposition of the great arteries. Tadalafil 20mg or placebo will be given over a study period of 3years. The primary endpoint is the change in mean end-systolic RV volumes from baseline to study end at 3years of follow-up (or at the time of permanent discontinuation of the randomized treatment if stopped before 3- years of follow-up), and will be measured by cardiovascular magnetic resonance imaging (CMR) or by cardiac computed tomography in patients with contraindications for CMR. Secondary endpoints are changes in RV ejection fraction, VO2max and NT-proBNP. ConclusionThe objective of this study is to assess the effect of PDE-5 inhibition with Tadalafil on RV size and function, exercise capacity and neurohumoral activation in adults with a systemic RV over a 3-year follow-up period.

Effects of phosphodiesterase-5 inhibition with sildenafil on calcium waves in cardiac myocytes

BackgroundDiastolic Ca2+ waves in cardiac myocytes lead to arrhythmias by inducing delayed after-depolarisations. Waves occur when sarcoplasmic reticulum (SR) content reaches a threshold level. The phosphodiesterase-5 inhibitor, sildenafil, is antiarrhythmic in mammalian myocardial ischaemia models, and in rat myocytes it reduces Ca2+ transient amplitude and SR Ca2+ content. We sought to determine effects of sildenafil on propensity to Ca2+ waves in the large mammal. MethodsSheep ventricular myocytes were voltage clamped and Ca2+ fluorescence measured using fura-2. Cells were paced at 0·5 Hz with depolarisations from −40mV to +10mV. When at steady state, waves were induced with 7·5–15 mM Ca2+. Upon regular waving, sildenafil (1 μM) was applied. To determine threshold SR Ca2+ content, caffeine (10 mM) was added immediately after a wave, and both wave and caffeine-induced Na+/Ca2+ exchanger current (INCX)were integrated. FindingsIncreasing external Ca2+ increased SR content and induced diastolic waves. Sildenafil abolished waves in seven of 11 cells. In cells where sildenafil terminated waves, SR content was reduced below threshold. In addition, sildenafil treatment was associated with reduced rate constant of SERCA (kSERCA −68·4% of control, p<0·0001), initial (first 4 s) increase in sarcolemmal efflux via INCX tail current (+190%, p=0·022), and reduced sarcolemmal influx via L-type Ca2+ current (ICa-L) (−29·8%, p=0·0015). In cells continuing to wave in sildenafil, SR threshold for waves was unchanged (123·8 μmol/L sildenafil vs 150·7, p=0·57). In unstimulated cells spontaneously waving in 10–15 mM Ca2+, sildenafil reduced wave frequency (6·3 waves per 20 s vs 2·7, p=0·0034). The effect of sildenafil on both wave models was abolished when cells were preincubated with the protein kinase G inhibitor, KT5823. InterpretationSildenafil suppresses waves induced by elevated external Ca2+ via a protein kinase G-dependent mechanism. This suppression is mediated by reduced SR content, which itself is caused by reduced SERCA function and possible reduced ICa-L. These findings highlight novel antiarrhythmic properties of phosphodiesterase-5 inhibition. FundingBritish Heart Foundation.

Effect of phosphodiesterase-5 inhibition on apoptosis and beta amyloid load in aged mice

Age-related cognitive decline is accompanied by an increase of neuronal apoptosis and a dysregulation of neuroplasticity-related molecules such as brain-derived neurotrophic factor and neurotoxic factors including beta amyloid (Aβ) peptide. Because it has been previously demonstrated that phosphodiesterase-5 inhibitors (PDE5-Is) protect against hippocampal synaptic dysfunction and memory deficits in mouse models of Alzheimer's disease and physiological aging, we investigated the effect of a treatment with the PDE5-I, sildenafil, on cell death, pro- and antiapoptotic molecules, and Aβ production. We demonstrated that chronic intraperitoneal injection of sildenafil (3 mg/kg for 3 weeks) decreased terminal deoxyuridine triphosphate nick end labeling-positive cells in the CA1 hippocampal area of 26–30-month-old mice, downregulating the proapoptotic proteins, caspase-3 and B-cell lymphoma 2-associated X, and increasing antiapoptotic molecules such as B-cell lymphoma protein-2 and brain-derived neurotrophic factor. Also, sildenafil reverted the shifting of amyloid precursor protein processing toward Aβ42 production and the increase of the Aβ42:Aβ40 ratio in aged mice. Our data suggest that PDE5-I might be beneficial to treat age-related detrimental features in a physiological mouse model of aging.

Effect of Phosphodiesterase-5 Inhibition on Exercise Capacity and Clinical Status in Heart Failure With Preserved Ejection Fraction

Studies in experimental and human heart failure suggest that phosphodiesterase-5 inhibitors may enhance cardiovascular function and thus exercise capacity in heart failure with preserved ejection fraction (HFPEF). To determine the effect of the phosphodiesterase-5 inhibitor sildenafil compared with placebo on exercise capacity and clinical status in HFPEF. Multicenter, double-blind, placebo-controlled, parallel-group, randomized clinical trial of 216 stable outpatients with HF, ejection fraction ≥50%, elevated N-terminal brain-type natriuretic peptide or elevated invasively measured filling pressures, and reduced exercise capacity. Participants were randomized from October 2008 through February 2012 at 26 centers in North America. Follow-up was through August 30, 2012. Sildenafil (n = 113) or placebo (n = 103) administered orally at 20 mg, 3 times daily for 12 weeks, followed by 60 mg, 3 times daily for 12 weeks. Primary end point was change in peak oxygen consumption after 24 weeks of therapy. Secondary end points included change in 6-minute walk distance and a hierarchical composite clinical status score (range, 1-n, a higher value indicates better status; expected value with no treatment effect, 95) based on time to death, time to cardiovascular or cardiorenal hospitalization, and change in quality of life for participants without cardiovascular or cardiorenal hospitalization at 24 weeks. Median age was 69 years, and 48% of patients were women. At baseline, median peak oxygen consumption (11.7 mL/kg/min) and 6-minute walk distance (308 m) were reduced. The median E/e' (16), left atrial volume index (44 mL/m2), and pulmonary artery systolic pressure (41 mm Hg) were consistent with chronically elevated left ventricular filling pressures. At 24 weeks, median (IQR) changes in peak oxygen consumption (mL/kg/min) in patients who received placebo (-0.20 [IQR, -0.70 to 1.00]) or sildenafil (-0.20 [IQR, -1.70 to 1.11]) were not significantly different (P = .90) in analyses in which patients with missing week-24 data were excluded, and in sensitivity analysis based on intention to treat with multiple imputation for missing values (mean between-group difference, 0.01 mL/kg/min, [95% CI, -0.60 to 0.61]). The mean clinical status rank score was not significantly different at 24 weeks between placebo (95.8) and sildenafil (94.2) (P = .85). Changes in 6-minute walk distance at 24 weeks in patients who received placebo (15.0 m [IQR, -26.0 to 45.0]) or sildenafil (5.0 m [IQR, -37.0 to 55.0]; P = .92) were also not significantly different. Adverse events occurred in 78 placebo patients (76%) and 90 sildenafil patients (80%). Serious adverse events occurred in 16 placebo patients (16%) and 25 sildenafil patients (22%). Among patients with HFPEF, phosphodiesterase-5 inhibition with administration of sildenafil for 24 weeks, compared with placebo, did not result in significant improvement in exercise capacity or clinical status. clinicaltrials.gov Identifier: NCT00763867.

Endothelial dysfunction enhances the pulmonary and systemic vasodilator effects of phosphodiesterase-5 inhibition in awake swine at rest and during treadmill exercise

Cardiovascular disease is characterized by impaired exercise capacity and endothelial dysfunction, i.e. reduced bioavailability of nitric oxide (NO). Phosphodiesterase-5 (PDE5) inhibition is a promising vasodilator therapy, but its effects on pulmonary and systemic hemodynamic responses to exercise in the absence, and particularly in the presence, of endothelial dysfunction have not been studied. We investigated the effects of PDE5 inhibitor EMD360527 in chronically instrumented swine at rest and during exercise with and without NO synthase inhibition (N(ω)-nitro-l-arginine; NLA). PDE5 inhibition caused a 19 ± 3% decrease in systemic vascular resistance (SVR) and a 24 ± 4% decrease in pulmonary vascular resistance (PVR) at rest. At maximal exercise, PDE5 inhibition caused a 13 ± 1% decrease in SVR and a 29 ± 3% decrease in PVR. NLA enhanced PDE5-inhibition-induced pulmonary (decrease in PVR 32 ± 12% at rest and 41 ± 3% during exercise) and systemic (decrease in SVR 24 ± 5% at rest and 18 ± 3% during exercise) vasodilation. Similarly, NLA increased the pulmonary and systemic vasodilation to nitroprusside and 8-bromo-cyclic guanosine monophosphate (cGMP), indicating that inhibition of NO synthase increases responsiveness to stimulation of the NO/cGMP pathway. Thus, PDE5 inhibition causes pulmonary and systemic vasodilation that is, respectively, maintained and slightly blunted during exercise. The degree of dilation in both the pulmonary and systemic beds were paradoxically enhanced in the presence of reduced bioavailability of NO, suggesting that this vasodilator therapy is most effective in patients with cardiovascular disease.

The effect of phosphodiesterase-5 inhibition by sildenafil citrate on inflammation and apoptosis in rat experimental colitis

AimsTo investigate the effect of sildenafil citrate (SIL) on the extent of tissue integrity, oxidant–antioxidant status and apoptosis in rats with colitis. Main methodsColitis was induced by trinitrobenzenesulphonic acid (TNBS) in 40% ethanol (30mg/ml; 0.8ml) given intrarectally to Sprague–Dawley rats. Sildenafil (25mg/kg/day) was administered after the induction of colitis and the treatment was continued for 7days. Other groups received subcutaneously either N(G)-nitro- L-arginine methyl ester (l-NAME; 25mg/kg) or N(G)-nitro-d-arginine methyl ester (d-NAME; 25mg/kg) before SIL. After decapitation, the distal colon was scored and stored for the measurement of malondialdehyde (MDA) level, glutathione (GSH) content, myeloperoxidase (MPO) activity and apoptosis. Oxidant generation was monitored by using chemiluminescence (CL). Blood was collected for tumor necrosis factor (TNF)-α and interleukin (IL)-10 assays. Key findingsThe macroscopic lesion score of the colitis group was reduced by SIL (p<0.01) and this effect was abolished by l-NAME (p<0.01). Increase in colonic MDA along with a concomitant decrease in GSH of the colitis group was reversed by SIL (p<0.01 and p<0.001, respectively). l-NAME prevented the effect of SIL on GSH content (p<0.001). Sildenafil also reduced the elevated MPO of the colitis group (p<0.001) and this effect was reversed by L-NAME (p<0.01). Increase in lucigenin CL and serum TNF-α levels in the colitis group were also prevented by SIL (p<0.001 and p<0.01, respectively). SignificanceSildenafil is beneficial in TNBS-induced rat colitis partially by nitric oxide-dependent mechanisms via the maintenance of oxidant–antioxidant status, prevention of apoptosis, superoxide production and cytokine release.

The effects of phosphodiesterase-5 inhibition with sildenafil on pulmonary hemodynamics and diffusion capacity, exercise ventilatory efficiency, and oxygen uptake kinetics in chronic heart failure

We sought to investigate the effects of sildenafil, a phosphodiesterase-5 (PDE(5)) inhibitor, on lung function and exercise performance in chronic heart failure (CHF). In CHF, nitric oxide-mediated regulation of lung vascular tone and alveolar-capillary membrane conductance is impaired and contributes to exercise intolerance. The potential for benefits due to increased nitric-oxide availability is unexplored. In 16 patients with CHF and 8 normal subjects, we measured-before and 60 min after sildenafil (50 mg) or placebo-ejection fraction, pulmonary hemodynamics, carbon monoxide diffusion capacity (DLco), with its membrane (D(M)) and capillary blood volume (V(c)) subcomponents, endothelial function (brachial reactive hyperemia) at rest, peak oxygen uptake (VO(2)), increments in VO(2) versus work rate (DeltaVO(2)/DeltaWR), changes in ventilation versus CO(2) production (VE/VCO(2)) slope, and recovery VO(2) time constant (tau) on exertion. In CHF, sildenafil did not affect cardiac index, wedge pulmonary pressure, or ejection fraction; it significantly (p < 0.01) decreased pulmonary mean artery pressure (-20.4%) and arteriolar resistance (-45.1%), VE/VCO(2) slope (-9.0%) and recovery tau (-25.8%), and increased (p < 0.01) DLco (+11.1%), D(M) (+9.9%) peak VO(2) (+19.7%), DeltaVO(2)/DeltaWR (+11.0%), and brachial reactive hyperemia (+33.3%). No variations occurred in normal subjects and after placebo. Changes in DLco were related to those in VE/VCO(2) slope (r = -0.71; p = 0.002), and changes in brachial hyperemia correlated with those in DeltaVO(2)/DeltaWR (r = 0.80; p = 0.0002). This study shows that in CHF PDE(5) inhibition modulates pulmonary pressure and vascular tone, and improves DLco, exercise peak VO(2), aerobic (DeltaVO(2)/DeltaWR) and ventilatory (VE/VCO(2) slope) efficiencies, and oxygen debt (recovery tau). Endothelial mechanisms may underlie these effects.

The effect of vardenafil, a potent and highly selective phosphodiesterase-5 inhibitor for the treatment of erectile dysfunction, on the cardiovascular response to exercise in patients with coronary artery disease

ObjectivesThe effect of vardenafil, a potent and highly selective phosphodiesterase-5 (PDE5) inhibitor, on symptom-limited exercise time, time to first awareness of angina, and time to ischemic threshold (ST-segment depression ≥1 mm from baseline) during exercise tolerance testing (ETT) was examined in patients with stable coronary artery disease (CAD). BackgroundErectile dysfunction (ED) is common among men with CAD. PDE5 inhibition is increasingly the preferred treatment option for ED. However, the effect of PDE5 inhibition on exercise-induced ischemia in CAD patients has received limited prospective evaluation. MethodsIn this double-blind, crossover, single-dose multicenter study, 41 men with reproducible stable exertional angina due to ischemic CAD received vardenafil 10 mg or placebo, followed by ETT (5 to 10 metabolic equivalents [METS], Bruce protocol) 1 h postdose. Sublingual nitrate use was prohibited for ≥24 h pre- and postexercise study days. End points included symptom-limited treadmill exercise time, time to first awareness of angina, time to ischemic threshold, and safety. ResultsRelative to placebo, vardenafil 10 mg did not alter exercise treadmill time (427 ± 105 s vs. 433 ± 109 s, p = 0.39), or time to first awareness of angina (292 ± 110 s vs. 291 ± 123 s, p = 0.59), but significantly prolonged time to ischemic threshold (334 ± 108 s vs. 381 ± 108, p = 0.0004). At peak exercise, vardenafil 10 mg did not alter blood pressure, heart rate, or rate-pressure product relative to placebo. The most common adverse events (facial flushing and headache) were of mild or moderate intensity, and short-lived. ConclusionsVardenafil 10 mg did not impair the ability of patients with stable CAD to exercise at levels equivalent or greater than that attained during sexual intercourse (average of 2.5 to 3.3 METS).