REVEAL risk scores applied to riociguat-treated patients in PATENT-2: Impact of changes in risk score on survival.

BACKGROUND: The Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL) risk score (RRS) calculator was developed using data derived from the REVEAL registry, and predicts survival in patients with pulmonary arterial hypertension (PAH) based on multiple patient characteristics. Herein we applied the RRS to a pivotal PAH trial database, the 12-week PATENT-1 and open-label PATENT-2 extension studies of riociguat. We examined the effect of riociguat vs placebo on RRS in PATENT-1, and investigated the prognostic implications of change in RRS during PATENT-1 on long-term outcomes in PATENT-2. METHODS: RRS was calculated post hoc for baseline and Week 12 of PATENT-1, and Week 12 of PATENT-2. Patients were grouped into risk strata by RRS. Kaplan-Meier estimates were made for survival and clinical worsening-free survival in PATENT-2 to evaluate the relationship between RRS in PATENT-1 and long-term outcomes in PATENT-2. RESULTS: A total of 396 patients completed PATENT-1 and participated in PATENT-2. In PATENT-1, riociguat significantly improved RRS (p = 0.031) and risk stratum (p = 0.018) between baseline and Week 12 compared with placebo. RRS at baseline, and at PATENT-1 Week 12, and change in RRS during PATENT-1 were significantly associated with survival (hazard ratios for a 1-point reduction in RRS: 0.675, 0.705 and 0.804, respectively) and clinical worsening-free survival (hazard ratios of 0.736, 0.716 and 0.753, respectively) over 2 years in PATENT-2. CONCLUSIONS: RRS at baseline and Week 12, and change in RRS, were significant predictors of both survival and clinical worsening-free survival. These data support the long-term predictive value of the RRS in a controlled study population.

Riociguat in patients with chronic thromboembolic pulmonary hypertension: results from an early access study.

BACKGROUND: Following positive results from the Phase III CHEST-1 study in patients with inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH), the Phase IIIb CTEPH early access study (EAS) was designed to assess the safety and tolerability of riociguat in real-world clinical practice, as well as to provide patients with early access to riociguat before launch. Riociguat is approved for the treatment of inoperable and persistent/recurrent CTEPH. METHODS: We performed an open-label, uncontrolled, single-arm, early access study in which 300 adult patients with inoperable or persistent/recurrent CTEPH received riociguat adjusted from 1 mg three times daily (tid) to a maximum of 2.5 mg tid. Patients switching from unsatisfactory prior pulmonary arterial hypertension (PAH)-targeted therapy (n = 84) underwent a washout period of at least 3 days before initiating riociguat. The primary aim was to assess the safety and tolerability of riociguat, with World Health Organization functional class and 6-min walking distance (6MWD) as exploratory efficacy endpoints. RESULTS: In total, 262 patients (87%) completed study treatment and entered the safety follow-up (median treatment duration 47 weeks). Adverse events were reported in 273 patients (91%). The most frequently reported serious adverse events were syncope (6%), right ventricular failure (3%), and pneumonia (2%). There were five deaths, none of which was considered related to study medication. The safety and tolerability of riociguat was similar in patients switched from other PAH-targeted therapies and those who were treatment naïve. In patients with data available, mean ± standard deviation 6MWD had increased by 33 ± 42 m at Week 12 with no clinically relevant differences between the switched and treatment-naïve subgroups. CONCLUSIONS: Riociguat was well tolerated in patients with CTEPH who were treatment naïve, and in those who were switched from other PAH-targeted therapies. No new safety signals were observed. TRIAL REGISTRATION: ClinicalTrials.org NCT01784562 . Registered February 4, 2013.

Long-Term Outcome of Patients With Chronic Thromboembolic Pulmonary Hypertension: Results From an International Prospective Registry.

BACKGROUND: Chronic thromboembolic pulmonary hypertension, a rare complication of acute pulmonary embolism, is characterized by fibrothrombotic obstructions of large pulmonary arteries combined with small-vessel arteriopathy. It can be cured by pulmonary endarterectomy, and can be clinically improved by medical therapy in inoperable patients. A European registry was set up in 27 centers to evaluate long-term outcome and outcome correlates in 2 distinct populations of operated and not-operated patients who have chronic thromboembolic pulmonary hypertension. METHODS AND RESULTS: A total of 679 patients newly diagnosed with chronic thromboembolic pulmonary hypertension were prospectively included over a 24-month period. Estimated survival at 1, 2, and 3 years was 93% (95% confidence interval [CI], 90-95), 91% (95% CI, 87-93), and 89% (95% CI, 86-92) in operated patients (n=404), and only 88% (95% CI, 83-91), 79% (95% CI, 74-83), and 70% (95% CI, 64-76) in not-operated patients (n=275). In both operated and not-operated patients, pulmonary arterial hypertension-targeted therapy did not affect survival estimates significantly. Mortality was associated with New York Heart Association functional class IV (hazard ratio [HR], 4.16; 95% CI, 1.49-11.62; P=0.0065 and HR, 4.76; 95% CI, 1.76-12.88; P=0.0021), increased right atrial pressure (HR, 1.34; 95% CI, 0.95-1.90; P=0.0992 and HR, 1.50; 95% CI, 1.20-1.88; P=0.0004), and a history of cancer (HR, 3.02; 95% CI, 1.36-6.69; P=0.0065 and HR, 2.15; 95% CI, 1.18-3.94; P=0.0129) in operated and not-operated patients, respectively. Additional correlates of mortality were bridging therapy with pulmonary arterial hypertension-targeted drugs, postoperative pulmonary hypertension, surgical complications, and additional cardiac procedures in operated patients, and comorbidities such as coronary disease, left heart failure, and chronic obstructive pulmonary disease in not-operated patients. CONCLUSIONS: The long-term prognosis of operated patients currently is excellent and better than the outcome of not-operated patients.

Survival in pulmonary hypertension in Spain: insights from the Spanish registry.

A pulmonary hypertension (PH) registry (Spanish Registry of Pulmonary Arterial Hypertension) was undertaken to analyse prevalence, incidence and survival of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) in Spain, and to assess the applicability of recent survival prediction equations. Voluntary reporting of previously diagnosed and incident PAH or CTEPH cases (July 2007-June 2008) was performed. Demographic, functional and haemodynamic variables were evaluated. 866 patients with PAH and 162 with CTEPH were included. PAH associated with toxic oil syndrome and pulmonary veno-occlusive disease were reported for the first time in a PAH registry. Estimated prevalences were as follows: PAH, 16 and CTEPH, 3.2 cases per million adult inhabitants (MAI). Estimated incidences were as follows: PAH, 3.7 and CTEPH, 0.9 cases per MAI per yr. 1-, 3- and 5-yr survival was 87%, 75% and 65%, respectively, with no differences between PAH and CTEPH. Male sex, right atrial pressure and cardiac index were independent predictors of death. Matching between observed survival and that predicted by different equations was closer when the characteristics of the cohorts were similar. Epidemiology and survival of PAH patients in the Spanish registry are similar to recent registries. Characteristics of the population from which survival prediction equations are derived influence their applicability to a different cohort. CTEPH is much less prevalent than PAH, although has a similar survival rate.

Chronic thromboembolic pulmonary hypertension (CTEPH): results from an international prospective registry.

BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) is often a sequel of venous thromboembolism with fatal natural history; however, many cases can be cured by pulmonary endarterectomy. The clinical characteristics and current management of patients enrolled in an international CTEPH registry was investigated. METHODS AND RESULTS: The international registry included 679 newly diagnosed (≤6 months) consecutive patients with CTEPH, from February 2007 until January 2009. Diagnosis was confirmed by right heart catheterization, ventilation-perfusion lung scintigraphy, computerized tomography, and/or pulmonary angiography. At diagnosis, a median of 14.1 months had passed since first symptoms; 427 patients (62.9%) were considered operable, 247 (36.4%) nonoperable, and 5 (0.7%) had no operability data; 386 patients (56.8%, ranging from 12.0%- 60.9% across countries) underwent surgery. Operable patients did not differ from nonoperable patients relative to symptoms, New York Heart Association class, and hemodynamics. A history of acute pulmonary embolism was reported for 74.8% of patients (77.5% operable, 70.0% nonoperable). Associated conditions included thrombophilic disorder in 31.9% (37.1% operable, 23.5% nonoperable) and splenectomy in 3.4% of patients (1.9% operable, 5.7% nonoperable). At the time of CTEPH diagnosis, 37.7% of patients initiated at least 1 pulmonary arterial hypertension-targeted therapy (28.3% operable, 53.8% nonoperable). Pulmonary endarterectomy was performed with a 4.7% documented mortality rate. CONCLUSIONS: Despite similarities in clinical presentation, operable and nonoperable CTEPH patients may have distinct associated medical conditions. Operability rates vary considerably across countries, and a substantial number of patients (operable and nonoperable) receive off-label pulmonary arterial hypertension-targeted treatments.

Implante de desfibrilador como prevención primaria de muerte súbita en pacientes en lista de espera de trasplante cardiaco: experiencia de un centro / Defibrillator implantation for the primary prevention of sudden death in patients awaiting cardiac transplantation: one center’s experience

Los pacientes incluidos en lista de espera de trasplante cardiaco frecuentemente presentan un perfil acorde a las recomendaciones actuales en cuanto al implante de desfibrilador automático implantable como prevención primaria de muerte súbita. El eventual trasplante a corto-medio plazo hace dudar de la efectividad de dicha terapia. Analizamos la incidencia de terapias administradas por el desfibrilador implantado como prevención primaria en pacientes en lista, así como la evolución histórica en la frecuencia de muerte súbita en nuestro centro. Se revisaron los 308 pacientes incluidos en lista desde 1998 hasta 2008. En 17 pacientes se indicó desfibrilador automático implantable como prevención primaria al momento de la inclusión. El 53% de éstos recibió terapias adecuadas, habiendo portado el dispositivo una media de 7,8 meses (±4,8). Sólo 1 paciente presentó terapias inadecuadas y ninguno sufrió complicaciones asociadas al dispositivo. La frecuencia de muerte súbita se ha reducido a lo largo de los últimos años(AU)

Patients who are on a waiting list for cardiac transplantation often have a clinical profile that satisfies current recommendations for the implantation of an implantable cardioverter–defibrillator for the primary prevention of sudden death. The prospect that transplantation may take place within the shortto- medium term puts the effectiveness of this therapy in doubt. We investigated the incidence of therapy delivered by implantable cardioverter–defibrillators implanted for primary prevention in patients awaiting cardiac transplantation. Recent changes in the incidence of sudden death at our center were also investigated. Data on 308 patients listed for heart transplantation between 1998 and 2008 were reviewed. An implantable cardioverter–defibrillator was indicated for primary prevention at initial evaluation in 17 patients. Of these, 53% received appropriate implantable cardioverter–defibrillator therapy while carrying an implantable cardioverter–defibrillator for amean period of 7.8months (+/-4.8). Only one patient received inappropriate therapy and none had any complications associated with device use. The frequency of sudden death has decreased over the course of recent years(AU)

Induction treatment with monoclonal antibodies for heart transplantation.

Individualization of induction therapy for heart transplantation (HT) is needed, given that only patients at significant risk for fatal rejection seem to present a favorable risk-benefit ratio. The question whether monoclonal interleukin 2 antagonists or antilymphocyte antibodies should be recommended remains unanswered. As most studies suggest that they have similar efficacy in preventing acute rejection, other variables related to safety or management costs should be taken into account. The cytokine release syndrome, associated with the use of OKT3, complicates management of HT patient. The experience in our center with 2 consecutive cohorts, treated with basiliximab (BAS) and OKT3, respectively, suggests that the use of BAS is associated, in addition to similar immunosuppressive efficacy and better safety profile than OKT3, with simpler patient management during the initial hospital stay, which could be associated with a reduction in posttransplant costs. Because few centers continue to use OKT3 as induction therapy in HT, more studies comparing cost-effectiveness of BAS vs polyclonal antilymphocyte antibodies (ATG) are needed.

Risk factors associated with moderate-to-severe renal dysfunction among heart transplant patients: results from the CAPRI study.

The longer survival of patients with heart transplantation (HT) favors calcineurin inhibitor-related chronic kidney disease (CKD). It behoves to identify risk factors. At 14 Spanish centers, data on 1062 adult patients with HT (age 59.2 ± 12.3 yr, 82.5% men) were collected at routine follow-up examinations. Glomerular filtration rate, GFR, was estimated using the four-variable MDRD equation, and moderate-or-severe renal dysfunction (MSRD) was defined as K/DOQI stage 3 CKD or worse. Time since transplant ranged from one month to 22 yr (mean 6.7 yr). At assessment, 26.6% of patients were diabetic and 63.9% hypertensive; 53.9% were taking cyclosporine and 33.1% tacrolimus; and 61.4% had MSRD. Among patients on cyclosporine or tacrolimus at assessment, multivariate logistic regression identified male sex (OR 0.44), pre- and post-HT creatinine (2.73 and 3.13 per mg/dL), age at transplant (1.06 per yr), time since transplant (1.05 per yr), and tacrolimus (0.65) as independent positive or negative predictors of MSRD. It is concluded that female sex, pre- and one-month post-HT serum creatinine, age at transplant, time since transplant, and immunosuppression with cyclosporine rather than tacrolimus may all be risk factors for development of CKD ≥ stage 3 by patients with HT.

[Update on geriatric cardiology]. / Actualización en cardiología geriátrica.

This article contains a review of the main developments in the field of geriatric cardiology reported during 2007, and discusses recent consensus statements. The article focuses on work dealing with the specific characteristics of elderly patients with ischemic heart disease, arrhythmias, heart failure, pulmonary hypertension and valvular heart disease.

Actualización en cardiología geriátrica / Update on Geriatric Cardiology

En este artículo se revisan los principales avances publicados durante el año 2007 en el ámbito de la cardiología geriátrica, así como los nuevos documentos de consenso. Nos hemos centrado en los trabajos que han mostrado las peculiaridades de los ancianos con cardiopatía isquémica, arritmias, insuficiencia cardiaca/hipertensión pulmonar y valvulopatías (AU)

This article contains a review of the main developments in the field of geriatric cardiology reported during 2007, and discusses recent consensus statements. The article focuses on work dealing with the specific characteristics of elderly patients with ischemic heart disease, arrhythmias, heart failure, pulmonary hypertension and valvular heart disease (AU)

[Transition from prostacyclin to bosentan in five patients with severe pulmonary hypertension: the switch is possible]. / Transición de prostaciclina a bosentán en 5 pacientes con hipertensión pulmonar severa: el cambio es posible.

Prostacyclin improves symptoms, exercise tolerance, and survival in patients with pulmonary arterial hypertension. However, the difficulty of administration (whether intravenous, subcutaneous, or by inhalation) often causes side effects that can reduce the patient's quality of life and which may sometimes be serious. Bosentan, an orally active endothelin receptor antagonist, improves functional class and exercise tolerance in these patients. We describe the successful transition from prostacyclin to bosentan in five patients with severe pulmonary arterial hypertension who suffered serious side effects with prostacyclin treatment.

Transición de prostaciclina a bosentán en 5 pacientes con hipertensión pulmonar severa: el cambio es posible / Transition from prostacyclin to bosentan in five patients with severe pulmonary hypertension: the switch is possible

La prostaciclina mejora los síntomas, la capacidad de ejercicio y la supervivencia en los pacientes con hipertensión arterial pulmonar. Sin embargo, sus complejas vías de administración (intravenosa, inhalada, subcutánea) ocasionan frecuentes efectos adversos que disminuyen la calidad de vida y pueden ser graves. Bosentán, un antagonista oral de los receptores de la endotelina, mejora la clase funcional y la capacidad de ejercicio en estos pacientes. Describimos la transición de prostaciclina a bosentán en 5 pacientes con hipertensión arterial pulmonar severa e importantes complicaciones secundarias al tratamiento con prostaciclina

Prostacyclin improves symptoms, exercise tolerance, and survival in patients with pulmonary arterial hypertension. However, the difficulty of administration (whether intravenous, subcutaneous, or by inhalation) often causes side effects that can reduce the patient's quality of life and which may sometimes be serious. Bosentan, an orally active endothelin receptor antagonist, improves functional class and exercise tolerance in these patients. We describe the successful transition from prostacyclin to bosentan in five patients with severe pulmonary arterial hypertension who suffered serious side effects with prostacyclin treatment

A randomized multicenter comparison of basiliximab and muromonab (OKT3) in heart transplantation: SIMCOR study.

BACKGROUND: Antilymphocytic antibodies have been long used for the prevention of acute rejection early after heart transplantation (HTx), but their adverse effects have limited their widespread use. Our aim was to evaluate the safety, tolerability, and efficacy of the novel anti-CD25 antibody basiliximab (BAS) compared with muromonab (OKT3). PATIENTS AND METHODS: In this multicenter study, 99 patients were randomly assigned to receive either BAS or OKT3 in the early post-HTx period. The primary endpoint was safety and tolerability. Specific safety variables were predefined for a better comparison of adverse effects. Secondary endpoints concerning anti-rejection efficacy were also evaluated. RESULTS: No adverse events related to study medication were found in the BAS group, whereas 23 were observed among patients receiving OKT3 (P<0.0001). The proportion of patients with predefined adverse events day 4 post-HTx was much higher with OKT3 than with BAS (43% vs. 4%; P<0.0001). Fever, acute pulmonary edema, hypotension, and other complications accounted for most of the difference. At 1-year follow-up, biopsy-proven rejection episodes grade>or=3A had occurred in 39.6% of BAS patients versus 40.4% of OKT3 patients (P=0.87). There were no differences in terms of severity and timing of acute rejection episodes. The number of infectious episodes, complications not related to study medication, and actuarial survival were similar in both groups. CONCLUSION: In this HTx study, induction therapy with BAS was safer and better tolerated than OKT3, without significant differences in efficacy outcomes.

[Advances in geriatric cardiology]. / Avances en cardiología geriátrica.

The continued aging of the population is an acknowledged fact. The proportion of individuals in the European Union aged over 65 years will reach 29.9% by 2050, almost double the present figure of 16.4%. Approximately one third of people in this age-group has clinically significant cardiovascular disease. Physicians dealing with cardiology in older patients have to be aware of the specific clinical and prognostic features of cardiovascular disease in the elderly, and with its treatment. Consequently, it is clear that continuing medical education in geriatric cardiology is essential, and that is one of the tasks of the Working Group on Geriatric Cardiology. This special issue provides a magnificent opportunity for presenting an update on important topics in geriatric cardiology, such as the aging of the cardiovascular system, heart failure, and atrial fibrillation.

BMPR2 gene rearrangements account for a significant proportion of mutations in familial and idiopathic pulmonary arterial hypertension.

Mutations of the BMPR2 gene predispose to pulmonary arterial hypertension (PAH), a serious, progressive disease of the pulmonary vascular system. However, despite the fact that most PAH families are consistent with linkage to the BMPR2 locus, sequencing only identifies mutations in some 55% of familial cases and between 10% and 40% of cases without a family history (idiopathic or IPAH). We therefore conducted a systematic analysis for larger gene rearrangements in panels of both familial and idiopathic PAH cases that were negative on sequencing of coding regions. Analysis of exon dosage across the entire gene using Multiplex Ligation-dependent Probe Amplification identified nine novel rearrangements and enabled full characterization at the exon level of previously reported deletions. Overall, BMPR2 rearrangements were identified in 7 of 58 families and 6 of 126 IPAH cases, suggesting that gross rearrangements underlie around 12% of all FPAH cases and 5% of IPAH. Importantly, two deletions encompassed all functional protein domains and are predicted to result in null mutations, providing the strongest support yet that the predominant molecular mechanism for disease predisposition is haploinsufficiency. Dosage analysis should now be considered an integral of part of the molecular work-up of PAH patients.

Avances en cardiología geriátrica / Advances in Geriatric Cardiology

El continuo envejecimiento de la población es una auténtica realidad. La media de personas de más de 65 años en la Unión Europea alcanzará el 29,9% en 2050, casi el doble del 16,4% que hay en la actualidad. Aproximadamente, un tercio de personas en esta edad tiene enfermedad cardiovascular clínica. Los médicos responsables del paciente cardiópata anciano deben estar familiarizados con las diferentes manifestaciones clínicas, pronósticas y de manejo de las enfermedades cardiovasculares en la senectud. Así, la necesidad de continuar la educación médica en cardiología geriátrica es evidente en sí, y ése es uno de los cometidos de la sección de cardiología geriátrica. Este número extraordinario de la revista es una magnifica oportunidad para actualizar aspectos importantes de la cardiología geriátrica, como el envejecimiento cardiovascular, la insuficiencia cardíaca y la fibrilación auricular (AU)

The continued aging of the population is an acknowledged fact. The proportion of individuals in the European Union aged over 65 years will reach 29.9% by 2050, almost double the present figure of 16.4%. Approximately one third of people in this age-group has clinically significant cardiovascular disease. Physicians dealing with cardiology in older patients have to be aware of the specific clinical and prognostic features of cardiovascular disease in the elderly, and with its treatment. Consequently, it is clear that continuing medical education in geriatric (..) (AU)

Pulmonary vascular remodeling in pulmonary hypertension due to chronic heart failure.

UNLABELLED: Pulmonary hypertension (PHT) associated with chronic heart failure (CHF) is a risk factor of right ventricular failure after heart transplantation (HT). Our aim was to study pulmonary vascular changes in patients with CHF and to assess any correlation with haemodynamic data. METHODS: We studied 17 HT recipients with preoperative CHF who died shortly after HT. Preoperative haemodynamic information was obtained immediately before HT. Vascular lesions in muscular arteries were assessed by linear morphometry. Haemodynamic data were correlated with the morphologic changes. RESULTS: Mean transpulmonary gradient (TPG) was 8.9+/-4.5 mm Hg and pulmonary vascular resistance (PVR) was 2.25+/-1.34 Wu. According to the threshold for at-risk PHT (TPG>12 mm Hg or PVR>2.5 Wu), six patients had at-risk PHT. Medial thickness was 23.82+/-7.23% in patients with at-risk PHT and 17.16+/-3.24% in patients without at-risk PHT (p=0.018). CONCLUSIONS: Medial hypertrophy of muscular pulmonary arteries is more common and severe than expected in patients with CHF, even in patients without at-risk PHT. This structural change could explain why PHT, even in range of values not excluding HT, is a risk factor for right ventricular failure after HT and influences post-HT haemodynamic behaviour.

[Efficacy of oral sildenafil as rescue therapy in patients with severe pulmonary arterial hypertension chronically treated with prostacyclin. Long-term results]. / Eficacia del sildenafilo por vía oral como terapia de rescate en pacientes con hipertensión arterial pulmonar severa en tratamiento crónico con prostaciclina. Resultados a largo plazo.

INTRODUCTION AND OBJECTIVE: Prostacyclin therapy is an effective treatment for severe pulmonary hypertension. Sildenafil, a selective phosphodiesterase type 5 inhibitor, induces selective vasodilatation of the pulmonary vessels. A synergistic effect has been described for these two drugs. The aim of this study was to evaluate the efficacy and safety of sildenafil as rescue therapy in patients with severe pulmonary hypertension on chronic treatment with prostacyclin whose clinical or functional course was unsatisfactory. PATIENTS AND METHOD: Observational study of 11 patients (7 men, 4 women, mean age 42 [8] years) diagnosed as having severe idiopathic pulmonary hypertension, who were receiving chronic prostacyclin therapy. Sildenafil was started after a worsening of their clinical or functional status. Baseline, 3-month and 12-month follow-up evaluations were based on functional status (NYHA functional class and 6-minute walking test), the presence of decompensated right heart failure and echocardiogram. RESULTS: Seven of the 11 patients showed significant improvements in exercise capacity (distance walked in 6 minutes) at 3 (+25 m) and 12 months' follow-up (+36 m). Improvements in functional class were seen, and heart failure disappeared. No significant adverse effects of sildenafil were detected. The echocardiographic parameters showed a significant reduction in right ventricular end-diastolic diameter and left ventricular diastolic eccentricity index. One patient died after 4 months of follow-up from sudden cardiac death. CONCLUSIONS: The addition of oral sildenafil to chronic prostacyclin treatment in patients with severe pulmonary hypertension improved functional capacity and reduced episodes of decompensated right heart failure, with good tolerance and no significant adverse effects.

Nitric oxide pathway and phosphodiesterase inhibitors in pulmonary arterial hypertension.

Pulmonary hypertension (PH) is a disease of various origins. Nitric oxide-a potent vasodilator-is a key player of pulmonary vasoregulation. Nitric oxide signaling is mainly mediated by the guanylate cyclase/cyclic guanylate monophosphate pathway. The effects of this second messenger system are limited by enzymatic degradation through phosphodiesterases (PDEs). Recently, beneficial effects of the oral PDE-5 inhibitor sildenafil (originally approved for the treatment of erectile dysfunction) were reported for the treatment of PH. We provide a brief overview of the experimental and clinical application of PDE inhibitors in the field of PH. In particular, studies reporting the clinical effectiveness of sildenafil are highlighted. This agent, despite oral application, displays characteristics of a pulmonary selective vasodilator. In addition, evidence shows that sildenafil is operative mainly in the vasculature of well-ventilated areas of the lung. However, to date, controlled randomized trials proving the efficacy of this approach for the treatment of pulmonary arterial hypertension are lacking. The results of such studies have to confirm the current encouraging findings before recommendations regarding the use of PDE-5 inhibitors as a new treatment for PH can be made.