sildenafil-citrate and Pulmonary-Embolism

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but debilitating and life-threatening complication of acute pulmonary embolism. CTEPH results from persistent obstruction of pulmonary arteries and progressive vascular remodelling. Not all patients presenting with CTEPH have a history of clinically overt pulmonary embolism. The diagnostic work-up to detect or rule out CTEPH should include ventilation-perfusion scintigraphy, which has high sensitivity and a negative predictive value of nearly 100%. CT angiography usually reveals typical features of CTEPH, including mosaic perfusion, part or complete occlusion of pulmonary arteries, and intraluminal bands and webs. Patients with suspected CTEPH should be referred to a specialist centre for right-heart catheterisation and pulmonary angiography. Surgical pulmonary endarterectomy remains the treatment of choice for CTEPH and is associated with excellent long-term results and a high probability of cure. For patients with inoperable CTEPH, various medical and interventional therapies are being developed.

Topics: Angioplasty, Balloon; Bosentan; Chronic Disease; Endarterectomy; Endothelin Receptor Antagonists; Enzyme Activators; Humans; Hypertension, Pulmonary; Phosphodiesterase 5 Inhibitors; Piperazines; Pulmonary Embolism; Purines; Pyrazoles; Pyrimidines; Sildenafil Citrate; Sulfonamides; Thromboembolism

Chronic thromboembolic pulmonary hypertension (CTEPH) is a life-threatening condition that historically has a poor outcome with supportive medical treatment. Pulmonary endarterectomy (PEA) is the treatment of choice and offers the only chance of cure. A significant proportion of patients is either not suitable due to the distal distribution of the disease or has persistent pulmonary hypertension (PH) after PEA. Despite the lack of licensed therapies for CTEPH, the similarities in pathobiology of pulmonary arterial hypertension (PAH) and CTEPH has led to the compassionate use of PAH therapies in CTEPH patients. This article reviews the pathobiology of CTEPH and summaries the available evidence for the use of PAH-targeted drugs in CTEPH.

Topics: Antihypertensive Agents; Bosentan; Chronic Disease; Compassionate Use Trials; Endarterectomy; Humans; Hypertension, Pulmonary; Piperazines; Pulmonary Embolism; Purines; Pyrazoles; Pyrimidines; Sildenafil Citrate; Sulfonamides; Sulfones; Treatment Outcome

Chronic thromboembolic pulmonary hypertension is one of the most common forms of pulmonary hypertension (PHT), but frequently remains undiagnosed and untreated. Pulmonary thrombendarterectomy is the treatment of choice, but only about 50 % of such patients are operable. About 15 % of patients are not improved by surgery, usually because of residual PHT with advanced vascular changes. Drug treatment has favorable effects in inoperable forms and in postoperative recurrence of PHT.

Topics: Antihypertensive Agents; Bosentan; Endarterectomy; Humans; Hypertension, Pulmonary; Iloprost; Piperazines; Pulmonary Embolism; Purines; Recurrence; Sildenafil Citrate; Splenectomy; Sulfonamides; Sulfones; Vasodilator Agents

To investigate if acute pulmonary vasodilation by sildenafil improves right ventricular function in patients with acute intermediate-high risk pulmonary embolism (PE).. Single center, explorative trial. Patients with PE were randomized to a single oral dose of sildenafil 50 mg (n = 10) or placebo (n = 10) as add-on to conventional therapy. The time from hospital admission to study inclusion was 2.3 ± 0.7 days. Right ventricular function was evaluated immediately before and shortly after (0.5-1.5 h) randomization by right heart catheterization (RHC), trans-thoracic echocardiography (TTE), and cardiac magnetic resonance (CMR). The primary efficacy endpoint was cardiac index measured by CMR.. Patients had acute intermediate-high risk PE verified by computed tomography pulmonary angiography, systolic blood pressure of 135 ± 18 (mean ± SD) mmHg, increased right ventricular/left ventricular ratio 1.1 ± 0.09 and increased troponin T 167 ± 144 ng/L. Sildenafil treatment did not improve cardiac index compared to baseline (0.02 ± 0.36 l/min/m2, p = 0.89) and neither did placebo (0.00 ± 0.34 l/min/m2, p = 0.97). Sildenafil lowered mean arterial blood pressure (- 19 ± 10 mmHg, p < 0.001) which was not observed in the placebo group (0 ± 9 mmHg, p = 0.97).. A single oral dose of sildenafil 50 mg did not improve cardiac index but lowered systemic blood pressure in patients with acute intermediate-high risk PE. The time from PE to intervention, a small patient sample size and low pulmonary vascular resistance are limitations of this study that should be considered when interpreting the results.. The trial was retrospectively registered at www.clinicaltrials.gov (NCT04283240) February 2nd 2020, https://clinicaltrials.gov/ct2/show/NCT04283240?term=NCT04283240&draw=2&rank=1 .

Topics: Administration, Oral; Aged; Aged, 80 and over; Arterial Pressure; Cardiac Catheterization; Echocardiography; Female; Heart Ventricles; Humans; Male; Middle Aged; Pulmonary Embolism; Sildenafil Citrate; Treatment Outcome; Vascular Resistance; Vasodilation

There are currently no licensed medical therapies for inoperable chronic thromboembolic pulmonary hypertension (CTEPH).. In this double-blind, placebo-controlled pilot study, 19 subjects with inoperable CTEPH were randomly assigned to sildenafil or placebo for 12 weeks. The primary end point was change in 6-min walking distance (6MWD). Secondary end points included changes in World Health Organization (WHO) class, cardiopulmonary hemodynamics, quality of life (QOL) scores, and N-terminal pro brain natriuretic peptide (NT-proBNP). All subjects were transferred to open-label sildenafil at the end of the study and offered repeat assessment at 12 months.. There were no significant differences between the two groups with respect to change in exercise capacity. However significant improvements were seen in WHO class and pulmonary vascular resistance (PVR). Seventeen subjects were eligible for reassessment at 12 months and demonstrated significant improvements in 6MWD, activity and symptom components of QOL, cardiac index, PVR, and NT-proBNP.. Although this pilot study was insufficiently powered to test the primary end point, it did suggest beneficial effects in favor of sildenafil in several secondary end points at both 3 months and 12 months. Further larger-scale trials of sildenafil in inoperable CTEPH are required to confirm these findings and potentially increase the treatment options available for this devastating disease.. The study protocol was registered with the UK National Research Register database (publication ID N0542136603).

Topics: Adult; Aged; Double-Blind Method; Drug Administration Schedule; Exercise Tolerance; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Pilot Projects; Piperazines; Pulmonary Embolism; Purines; Quality of Life; Sildenafil Citrate; Sulfones; Treatment Outcome; Vascular Resistance; Vasodilator Agents

Research comparing bosentan and macitentan in chronic thromboembolic pulmonary hypertension (CTEPH) is scarce, although macitentan might have superior pharmacologic properties. We present the first real-world, 2-year follow-up results and compare clinical outcomes of both drugs in CTEPH.. All consecutive, technical inoperable or residual CTEPH patients receiving bosentan or macitentan, diagnosed in our multidisciplinary team between January 2003 and January 2019, were included. We report and compare survival, clinical worsening (CW), adverse events, WHO FC, NT-proBNP and 6-min walking test (6MWT) until 2 years after medication initiation.. In total, 112 patients receiving bosentan or macitentan (58% female, mean age 62 ± 14 years, 68% WHO FC III/IV, 51% bosentan) could be included. Mean treatment duration was 1.9 ± 0.4 years for bosentan and 1.2 ± 0.6 years for macitentan. Two-year survival rate was 91% for bosentan and 80% for macitentan (HR mortality macitentan 1.85 [0.56-6.10], p = 0.31). Two-year CW-free survival was 81% and 58%, respectively (HR CW macitentan 2.16 [0.962-4.87], p = 0.06). Right atrial pressure, cardiac output (for mortality alone) and 6MWT lowest saturation were multivariate predictors at baseline. Overall adverse event rates were comparable and WHO FC, NT-proBNP and 6MWT distance improved similar for both drugs till 2-year follow-up.. CTEPH patients receiving bosentan or macitentan have improved clinical outcomes till 2-year follow-up, without significant differences in outcomes between both therapies.

Topics: Aged; Bosentan; Chronic Disease; Drug Therapy, Combination; Endarterectomy; Endothelin Receptor Antagonists; Enzyme Activators; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Phosphodiesterase 5 Inhibitors; Pulmonary Embolism; Pyrazoles; Pyrimidines; Retrospective Studies; Sildenafil Citrate; Sulfonamides; Survival Rate; Walk Test

The current study aimed to investigate the effects of sildenafil and N-acetylcysteine (NAC) on the haemodynamics in a rabbit model of acute pulmonary thromboembolism (APT). We developed an APT model using healthy male China big-ear rabbits (2.7 ± 0.4 kg). The rabbits were divided into five groups subjected to various interventions. We recorded the haemodynamic parameters and assessed the oxidative stress and lipid peroxidation response in the groups. Additionally, we detected apoptosis-associated molecules, FoxO1, Bad and Bcl-2, in the lung tissue. Gelatine zymography was used to detect matrix metalloproteinase (MMP) activity in bronchoalveolar lavage (BLA). Pulmonary artery endothelial cells were isolated, and their apoptosis rates and MMP activity were assayed. N-acetylcysteine potentiated the haemodynamic-improving effect of sildenafil and significantly inhibited the oxidative stress response. N-acetylcysteine combined with sildenafil decreased MMP-2 and MMP-9 activity and NO consumption and inhibited apoptosis of pulmonary arterial endothelial cells. Moreover, NAC combined with sildenafil inhibited the expression of MCP-1 and p-p38 MAPK. Thus, NAC potentiates the haemodynamic-improving effect of sildenafil in a rabbit model of acute pulmonary thromboembolism via the MCP-1 and p38 MAPK signalling pathway. This study may provide a promising treatment method for APT.

Topics: Acetylcysteine; Acute Disease; Animals; Apoptosis; Cell Count; Chemokine CCL2; Disease Models, Animal; Drug Synergism; Endothelial Cells; Hemodynamics; Lipid Peroxidation; Lung; Male; MAP Kinase Signaling System; Matrix Metalloproteinase 9; Neutrophils; Nitric Oxide; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Pulmonary Embolism; Rabbits; Sildenafil Citrate

A proportion of patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) do not achieve treatment goals or experience side effects on their current therapy. In such cases, switching patients to a new drug while discontinuing the first may be a viable and appropriate treatment option. CAPTURE was designed to investigate how physicians manage the switching of patients to riociguat in real-world clinical practice. Observations from the study were used to assess whether recommendations in the riociguat prescribing information are reflected in clinical practice.. CAPTURE was an international, multicenter, uncontrolled, retrospective chart review that collected data from patients with PAH or inoperable or persistent/recurrent CTEPH who switched to riociguat from another pulmonary hypertension (PH)-targeted medical therapy. The primary objective of the study was to understand the procedure undertaken in real-world clinical practice for patients switching to riociguat.. Of 127 patients screened, 125 were enrolled in CAPTURE. The majority of patients switched from a phosphodiesterase type 5 inhibitor (PDE5i) to riociguat and the most common reason for switching was lack of efficacy. Physicians were already using the recommended treatment-free period when switching patients to riociguat from sildenafil, but a slightly longer period than recommended for tadalafil. In line with the contraindication, the majority of patients did not receive riociguat and PDE5i therapy concomitantly. Physicians also followed the recommended dose-adjustment procedure for riociguat.. Switching to riociguat from another PH-targeted therapy may be feasible in real-world clinical practice in the context of the current recommendations.

Topics: Aged; Aged, 80 and over; Chronic Disease; Drug Substitution; Enzyme Activators; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Phosphodiesterase 5 Inhibitors; Pulmonary Embolism; Pyrazoles; Pyrimidines; Retrospective Studies; Sildenafil Citrate; Tadalafil

Topics: Angioplasty, Balloon; Cyclic Nucleotide Phosphodiesterases, Type 1; Drug Therapy, Combination; Endarterectomy; Epoprostenol; Genome-Wide Association Study; Hemodynamics; Humans; Hypertension, Pulmonary; Japan; Molecular Targeted Therapy; Phenylpropionates; Phosphodiesterase 5 Inhibitors; Practice Guidelines as Topic; Pulmonary Embolism; Pyridazines; Randomized Controlled Trials as Topic; Registries; Sildenafil Citrate; Tadalafil

This study evaluated the incremental effect of riociguat on pulmonary hemodynamics in patients with inoperative or persistent chronic thromboembolic pulmonary hypertension (CTEPH) treated previously with sildenafil.. The retrospective study included 28 patients diagnosed with CTEPH who were ineligible for surgical treatment due to distal thrombi location or who suffered from persistent CTEPH after pulmonary endarterectomy and who were treated with sildenafil at a dose of 25 mg TID for a minimum of 3 months. Sildenafil was subsequently discontinued, and riociguat therapy was started with gradually increasing doses. Right heart catheterization was performed and WHO functional class (FC) was assessed in each patient at three time points: before starting sildenafil therapy (baseline), before the transition to riociguat, and after 3 to 6 months of therapy with riociguat.. Compared to baseline, the use of sildenafil and riociguat significantly decreased pulmonary vascular resistance (PVR) (10.47 ± 3.56 vs. 7.81 ± 3.58 Wood units, p < 0.001) and mean pulmonary arterial pressure (PAP) (54.1 ± 11.6 vs. 46.1 ± 13.2 mm Hg; p < 0.001) while increasing cardiac output (CO) (4.31 ± 0.88 vs. 4.85 ± 0.87 L/min; p = 0.007). Switching from sildenafil to riociguat reduced PVR by 14% (p = 0.005) and the mean PAP by 6% (p = 0.03) while increasing CO by 11% (p = 0,002). The number of patients with WHO FC III and IV symptoms decreased from 71,4% to 57,1% (p = 0,02) after the change from sildenafil to riociguat.. Replacing sildenafil with riociguat in patients with inoperable or persistent CTEPH may improve pulmonary hemodynamics and FC.

Topics: Aged; Aged, 80 and over; Chronic Disease; Drug Substitution; Enzyme Activators; Female; Hemodynamics; Humans; Hypertension, Pulmonary; Lung; Male; Middle Aged; Pulmonary Embolism; Pyrazoles; Pyrimidines; Retrospective Studies; Sildenafil Citrate; Treatment Outcome; Vasodilator Agents

Topics: Adult; Age Distribution; Aged; Anticoagulants; Bosentan; Chronic Disease; Female; Humans; Hypertension, Pulmonary; Incidence; Latvia; Male; Middle Aged; Phenylpropionates; Prevalence; Pulmonary Embolism; Pyrazoles; Pyridazines; Pyridones; Registries; Rivaroxaban; Sex Distribution; Sildenafil Citrate; Sulfonamides; Vasodilator Agents; Warfarin; Young Adult

Symptoms in patients with chronic thromboembolic pulmonary hypertension (CTEPH) predominantly occur during exercise, while haemodynamic assessment is generally performed at rest. We hypothesised that exercise imaging of RV function would better explain exercise limitation and the acute effects of pulmonary vasodilator administration than resting measurements.. Fourteen patients with CTEPH and seven healthy control subjects underwent cardiopulmonary testing to determine peak exercise oxygen consumption (VO2peak) and ventilatory equivalent for carbon dioxide (VE/VCO2) at the anaerobic threshold. Subsequently, cardiac MRI was performed at rest and during supine bicycle exercise with simultaneous invasive measurement of mean pulmonary arterial pressure (mPAP) before and after sildenafil.. During exercise, patients with CTEPH had a greater increase in the ratio of mPAP relative to cardiac output (CO) than controls (6.7 (5.1-8.7) vs 0.94 (0.86-1.8) mm Hg/L/min; p < 0.001). Stroke volume index (SVi) and RVEF increased during exercise in controls, but not in patients with CTEPH (interaction p < 0.001). Sildenafil decreased the mPAP/CO slope and increased SVi and RVEF in patients with CTEPH (p < 0.05) but not in controls. In patients with CTEPH, RVEF reserve correlated moderately with VO2peak (r = 0.60; p = 0.030) and VE/VCO2 (r = -0.67; p = 0.012). By contrast, neither VO2peak nor VE/VCO2 correlated with resting RVEF.. Exercise measures of RV function explain much of the variance in the exercise capacity of patients with CTEPH while resting measures do not. Sildenafil increases SVi during exercise in patients with CTEPH, but not in healthy subjects.

Topics: Chronic Disease; Exercise; Exercise Test; Female; Heart Ventricles; Humans; Hypertension, Pulmonary; Magnetic Resonance Imaging, Cine; Male; Middle Aged; Oxygen Consumption; Piperazines; Pulmonary Embolism; Pulmonary Wedge Pressure; Purines; Sildenafil Citrate; Sulfonamides; Treatment Outcome; Vasodilator Agents; Ventricular Function, Right

Sildenafil is a pulmonary anti-hypertensive agent whose action could be modified by different fractions of inspired oxygen (FiO2). We compared the effects of pure oxygen (FiO2 > 90%) or room air (21% FiO2) on the cardiopulmonary actions of sildenafil in sheep with acute pulmonary embolism (APE).. Thirty-two anesthetized, mechanically ventilated sheep (34.9 ± 5.4 kg), were randomly distributed into four groups (n = 8 per group): FiO2 > 90% without intervention; APE induced by microspheres with FiO2 > 90%, followed 30 min later by placebo (Emb90); or APE followed 30 min later by intravenous sildenafil (0.7 mg/kg over 30 min) with FiO2 > 90% (Emb + Sild90) or 21% FiO2 (Emb + Sild21) [Corrected]. Variables were recorded until 30 min after the end of treatment administration.. Microsphere injection increased (P < 0.05) mean pulmonary artery pressure (MPAP) in all embolized groups (111-140% higher than that of baseline). Compared with values recorded 30 min after induction of APE (E30), sildenafil induced greater decreases in MPAP in the Emb + Sil90 group than in the Emb + Sil21 group (23% and 14% lower than E30, respectively). Hypotension (mean arterial pressure < 60 mm Hg) was precipitated by sildenafil due to systemic vasodilation in the Emb + Sil21 group. Embolization lowered the PaO2/FiO2 ratio and increased venous admixture, but sildenafil did not alter the oxygenation impairment induced by APE.. Sildenafil induces a more consistent pulmonary anti-hypertensive effect and causes less interference with the systemic circulation with the concomitant use of pure oxygen than that with room air in the APE setting.

Topics: Animals; Antihypertensive Agents; Blood Pressure; Cardiac Output; Heart Rate; Hypertension, Pulmonary; Oxygen; Piperazines; Pulmonary Embolism; Pulmonary Wedge Pressure; Purines; Respiratory Mechanics; Sheep; Sildenafil Citrate; Sulfonamides; Vascular Resistance

Patients with normalized mean pulmonary artery pressure (mPAP) after pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) do not always regain normal exercise capacity. We evaluated right ventricular function, its interaction with both pulsatile and resistive afterload, and the effect of sildenafil during exercise in these patients.. Fourteen healthy controls, 15 CTEPH patients, and 7 patients with normalized resting mPAP (≤25 mm Hg) post-PEA underwent cardiopulmonary exercise testing, followed by cardiac magnetic resonance imaging with simultaneous invasive mPAP measurement during incremental supine cycling exercise. Peak oxygen consumption and peak heart rate were significantly reduced in post-PEA and CTEPH patients compared to controls. The mPAP-cardiac output slope was steeper in post-PEA patients than in controls and similar to CTEPH. Relative to controls, resting right ventricular ejection fraction was reduced in CTEPH, but not in post-PEA patients. In contrast, peak exercise right ventricular ejection fraction was reduced both in post-PEA and CTEPH patients. Exercise led to reduction of pulmonary arterial compliance in all groups. Nevertheless, resting pulmonary arterial compliance values in CTEPH and post-PEA patients were even lower than those in controls at peak exercise. In post-PEA patients, sildenafil did not affect resting hemodynamics nor right ventricular function, but decreased the mPAP/cardiac output slope and increased peak exercise right ventricular ejection fraction.. Exercise intolerance in post-PEA patients is explained by abnormal pulmonary vascular reserve and chronotropic incompetence. The mPAP/cardiac output slope and pulmonary arterial compliance are sensitive measures demonstrating abnormal resistive and pulsatile pulmonary vascular function in post-PEA patients. These abnormalities are partially attenuated with sildenafil.

Topics: Adult; Aged; Arterial Pressure; Bicycling; Case-Control Studies; Catheterization, Swan-Ganz; Chronic Disease; Compliance; Endarterectomy; Exercise Test; Exercise Tolerance; Female; Heart Rate; Hemodynamics; Humans; Hypertension, Pulmonary; Magnetic Resonance Imaging; Male; Middle Aged; Oxygen Consumption; Phosphodiesterase 5 Inhibitors; Predictive Value of Tests; Pulmonary Artery; Pulmonary Embolism; Recovery of Function; Risk Factors; Sildenafil Citrate; Stroke Volume; Treatment Outcome; Ventricular Function, Right; Young Adult

We aimed to study whether pulmonary arterial distensibility (PAD) correlates with hemodynamic parameters in chronic thromboembolic pulmonary hypertension (CTEPH) using electrocardiogram (ECG)-gated 320-slice multidetector computed tomography (MDCT).. ECG-gated 320-slice MDCT and right heart catheterization (RHC) was performed in 53 subjects (60.6±11.4 years old; 37 females) with CTEPH. We retrospectively measured the minimum and maximum values of the cross sectional area (CSA) of the main pulmonary artery (mainPA), right pulmonary artery (rtPA), and left pulmonary artery (ltPA) during one heartbeat. PAD was calculated using the following formula: PAD = [(CSAmaximum-CSAminimum)/CSAmaximum]×100(%). The correlation between hemodynamic parameters and PAD was assessed. Mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR) were 40.8±8.7 mmHg and 8.3±3.0 wood units, respectively. PAD values were as follows: mainPA (14.0±5.0%), rtPA (12.8±5.6%), and ltPA (9.7±4.6%). Good correlations existed between mainPAD, with mPAP (r = -0.594, p<0.001) and PVR (r = -0.659, p<0.001). The correlation coefficients between rtPAD and ltPAD with pulmonary hemodynamics were all lower or equal than for mainPAD.. PAD measured using ECG-gated 320-slice MDCT correlates with pulmonary hemodynamics in subjects with CTEPH. The mainPA is suitable for PAD measurement.

Topics: Aged; Chronic Disease; Female; Hemodynamics; Humans; Hypertension, Pulmonary; Male; Middle Aged; Multidetector Computed Tomography; Oxygen Inhalation Therapy; Piperazines; Pulmonary Artery; Pulmonary Embolism; Purines; Risk Factors; Sildenafil Citrate; Sulfonamides; Treatment Outcome; Vascular Capacitance; Vasodilator Agents

An 84-year-old woman with pulmonary hypertension (PH) secondary to chronic pulmonary thromboembolism suffered from continuous warfarin dependent bleeding from sigmoid colon cancer. Sigmoidectomy was scheduled to control continuous bleeding. Six hours after discontinuation of anticoagulant therapy for elective sigmoidectomy, the patient showed hypoxia, pulmonary thromboembolism and pulmonary hypertension with right ventricular systolic pressure (RVSP) of 81 mmHg. The operation was postponed and heparin was infused. Since two-day heparinization therapy did not improve PH, oral administration of sildenafil citrate 60 mg daily was initiated. Seven days after initiation of sildenafil administration, RVSP decreased to 49 mmHg without improvement of hypoxia. Sigmoidectomy was performed under general anesthesia. The patient showed severe hypotension managed with noradrenaline and dopamine infusion during and after surgery, resulting from interaction between sildenafil and vasodilators. The patient was discharged 36 days after the operation without complications.

Topics: Aged, 80 and over; Colon, Sigmoid; Female; Humans; Hypertension, Pulmonary; Perioperative Care; Piperazines; Pulmonary Embolism; Purines; Sildenafil Citrate; Sulfones; Vasodilator Agents

We report on the successful treatment with sildenafil of a unique case of severe chronic thromboembolic pulmonary hypertension which developed as a late complication in a 71-year-old heart transplant recipient, with focus on the potential therapeutic challenges encountered in the management of such a peculiar association of clinical conditions.

Topics: Aged; Antihypertensive Agents; Heart Transplantation; Humans; Hypertension, Pulmonary; Male; Phosphodiesterase 5 Inhibitors; Piperazines; Pulmonary Embolism; Purines; Sildenafil Citrate; Sulfones; Treatment Outcome

We investigated whether atorvastatin has beneficial hemodynamic effects during acute pulmonary thromboembolism (APT) and whether sildenafil improves these effects. We studied the involvement of oxidative stress, matrix metalloproteinases (MMPs), and neutrophil activation. APT was induced with autologous blood clots (500 mg/kg) in anesthetized male lambs pretreated with atorvastatin (10 mg/kg/day, subcutaneously; 1 week) or vehicle (dimethyl sulfoxide 10% subcutaneously). Sildenafil (0.7 mg/kg intravenously) or saline infusions were performed 60 min after APT induction. Non-embolized control animals received saline. APT significantly increased pulmonary vascular resistance index (PVRI) and mean pulmonary artery pressure (MPAP) by approximately 310% and 258% respectively. While atorvastatin pretreatment attenuated these increases (~150% and 153%, respectively; P < 0.05), its combination with sildenafil was associated with lower increases in PVRI and MPAP (~32% and 36%, respectively). Gelatin zymography showed increased MMP-9 and MMP-2 levels in the bronchoalveolar lavage, and increased MMP-9 levels in plasma from embolized animals. Atorvastatin pretreatment attenuated bronchoalveolar lavage MMP-2 increases. The combination of drugs blunted the MMPs increases in bronchoalveolar lavage and plasma (P < 0.05). Neutrophils accumulated in bronchoalveolar lavage after APT, and atorvastatin pretreatment combined with sildenafil (but not atorvastatin alone) attenuated this effect (P < 0.05). APT increased lung lipid peroxidation and total protein concentrations in bronchoalveolar lavage, thus indicating oxidative stress and alveolar-capillary barrier damage, respectively. Both increases were attenuated by atorvastatin pretreatment alone or combined with sildenafil (P < 0.05). We conclude that pretreatment with atorvastatin protects against the pulmonary hypertension associated with APT and that sildenafil improves this response. These findings may reflect antioxidant effects and inhibited neutrophils/MMPs activation.

Topics: Acute Disease; Animals; Atorvastatin; Bronchoalveolar Lavage; Drug Synergism; Enzyme Activation; Heart Ventricles; Hemodynamics; Heptanoic Acids; Lipid Peroxidation; Lung; Male; Matrix Metalloproteinases; Myocytes, Cardiac; Neutrophils; Oxidative Stress; Piperazines; Pulmonary Embolism; Purines; Pyrroles; Sildenafil Citrate; Sulfones

Topics: Acute Disease; Adult; Cardiac Output, Low; Catheterization; Critical Care; Electrocardiography; Female; Femoral Artery; Gastrectomy; Humans; Multiple Sclerosis; Peptic Ulcer Perforation; Piperazines; Pulmonary Embolism; Purines; Sildenafil Citrate; Sulfones; Thrombolytic Therapy; Vasodilator Agents; Vena Cava Filters

While endogenous nitric oxide (NO) may be relevant to the beneficial hemodynamic effects produced by sildenafil during acute pulmonary embolism (APE), huge amounts of inducible NO synthase (iNOS)-derived NO may contribute to lung injury. We hypothesized that iNOS inhibition with S-methylisothiourea could attenuate APE-induced increases in oxidative stress and pulmonary hypertension and, therefore, could improve the beneficial hemodynamic and antioxidant effects produced by sildenafil during APE. Hemodynamic evaluations were performed in non-embolized dogs treated with saline (n=4), S-methylisothiourea (0.01 mg/kg followed by 0.5 mg/kg/h, n=4), sildenafil (0.3 mg/kg, n=4), or S-methylisothiourea followed by sildenafil (n=4), and in dogs that received the same drugs and were embolized with silicon microspheres (n=8 for each group). Plasma nitrite/nitrate (NOx) and thiobarbituric acid reactive substances (TBARS) concentrations were determined by Griess and a fluorometric assay, respectively. APE increased mean pulmonary arterial pressure (MPAP) and pulmonary vascular resistance index (PVRI) by 25±1.7 mm Hg and by 941±34 dyn s cm(-5) m(-2), respectively. S-methylisothiourea neither attenuated APE-induced pulmonary hypertension, nor enhanced the beneficial hemodynamic effects produced by sildenafil after APE (>50% reduction in pulmonary vascular resistance). While sildenafil produced no change in plasma NOx concentrations, S-methylisothiourea alone or combined with sildenafil blunted APE-induced increases in NOx concentrations. Both drugs, either alone or combined, produced antioxidant effects. In conclusion, although iNOS-derived NO may play a key role in APE-induced oxidative stress, our results suggest that the iNOS inhibitor S-methylisothiourea neither attenuates APE-induced pulmonary hypertension, nor enhances the beneficial hemodynamic effects produced by sildenafil.

Topics: Acute Disease; Animals; Dogs; Female; Hemodynamics; Isothiuronium; Male; Nitrates; Nitric Oxide; Nitric Oxide Synthase Type II; Nitrites; Oxidative Stress; Piperazines; Pulmonary Embolism; Purines; Sildenafil Citrate; Sulfones; Thiobarbituric Acid Reactive Substances

Inhibition of matrix metalloproteinases (MMPs) improves the hemodynamics during acute pulmonary embolism (APE) and oxidative stress upregulates MMPs. We compared the effects of different NO-cGMP pathway activators on APE-induced increases in MMPs.. Hemodynamic and biochemical evaluations were performed in non-embolized dogs treated with saline (N=5), and in microspheres embolized dogs receiving saline (n=9), or nitrite (6.75 micromol/kg i.v. over 15 min followed by 0.28 micromol/kg/min; n=5), or sildenafil (0.25 mg/kg; n=5), or BAY 41-2272 (0.03, 0.1, 0.3, and 1 mg/kg/h; n=5). Plasma thiobarbituric acid reactive substances (TBARS) concentrations were determined. Zymograms of plasma samples were performed, and in vitro antioxidant effects or inhibition of MMPs by these drugs were examined.. APE increased mean pulmonary artery pressure by ~25 mmHg. Nitrite, BAY 41-2272, or sildenafil reversed this increase by ~40% (P<0.05). Similar effects were seen on the pulmonary vascular resistance. While both nitrite and sildenafil produced no systemic effects, the highest dose of BAY 41-2272 produced systemic hypotension (P<0.05). While nitrite and sildenafil blunted the increases in plasma pro-MMP-9 levels and TBARS (all P<0.05), BAY 41-2272 produced no such effects. Nitrite and sildenafil produced in vitro antioxidant effects and inhibited MMPs only at high concentrations. BAY 41-2272 produced no such effects.. Activation of the NO-cGMP pathway with nitrite or sildenafil, but not with BAY 41-2272, attenuates APE-induced oxidative stress and increased MMP-9 levels. These findings are consistent with the idea that NO-cGMP pathway activators with antioxidant effects prevent the release of MMP-9 during APE.

Topics: Acute Disease; Animals; Disease Models, Animal; Dogs; Female; Humans; Male; Matrix Metalloproteinase 9; Matrix Metalloproteinase Inhibitors; Nitrites; Oxidative Stress; Phosphodiesterase Inhibitors; Piperazines; Pulmonary Embolism; Purines; Pyrazoles; Pyridines; Sildenafil Citrate; Sulfones

Topics: Chronic Disease; Endarterectomy; Humans; Hypertension, Pulmonary; Piperazines; Pulmonary Embolism; Purines; Sildenafil Citrate; Sulfones; Vasodilator Agents

Acute pulmonary embolism produces acute pulmonary hypertension, which can be counteracted by activating the nitric oxide-cyclic guanosine 3',5'-monophosphate (cGMP) pathway. While previous studies have shown that sildenafil (an inhibitor of cGMP-specific phosphodiesterase type 5) or nitrite (a storage molecule for nitric oxide) produces beneficial effects during acute pulmonary embolism, no previous study has examined whether the combination of these drugs can produce additive effects. Here, we expand previous findings and examine whether sildenafil enhances the beneficial haemodynamic effects produced by a low-dose infusion of nitrite in a dog model of acute pulmonary embolism. Haemodynamic and arterial blood gas evaluations were performed in non-embolized dogs treated with saline (n = 4), and in embolized dogs (intravenous injections of microspheres) that received nitrite (6.75 micromol/kg intravenously over 15 min. followed by 0.28 micromol/kg/min.) and sildenafil (0.25 mg/kg over 30 min.; n = 8), or nitrite followed by saline (n = 8), or saline followed by sildenafil (n = 7), or only saline (n = 8). Plasma thiobarbituric acid-reactive substances (TBARS) concentrations were determined using a fluorometric method. Acute pulmonary embolism increased pulmonary artery pressure by approximately 24 mmHg. While the infusion of nitrite or sildenafil infusions reversed this increase by approximately 42% (both P < 0.05), the combined infusion of both drugs reversed this increase by approximately 58% (P < 0.05). Similar effects were seen on the pulmonary vascular resistance index. Nitrite or sildenafil alone produced no significant hypotension. However, the combined infusion of both drugs caused transient hypotension (P < 0.05). Both drugs, either alone or combined, blunted the increase in TBARS concentrations caused by acute pulmonary embolism (all P < 0.05). These results suggest that sildenafil improves the beneficial haemodynamic effects of nitrite during acute pulmonary embolism.

Topics: Acute Disease; Animals; Blood Pressure; Disease Models, Animal; Dogs; Drug Synergism; Drug Therapy, Combination; Female; Hemodynamics; Hypertension, Pulmonary; Infusions, Intravenous; Lipid Peroxides; Male; Phosphodiesterase Inhibitors; Piperazines; Pulmonary Artery; Pulmonary Embolism; Purines; Respiration; Sildenafil Citrate; Sodium Nitrite; Sulfones; Vascular Resistance

To assess the efficacy of treatment with sildenafil monotherapy in patients with pulmonary hypertension.. An observational study was undertaken in 11 patients with pulmonary hypertension in functional class II or III who received treatment with sildenafil (150 mg/day). Seven of the patients had inoperable chronic thromboembolic pulmonary hypertension and 4 had pulmonary arterial hypertension. To assess treatment response, the following parameters were assessed during follow-up at 3, 6, and 12 months: exercise tolerance in the 6-minute walk test, change in functional class, and systolic pulmonary arterial pressure measured by echocardiography.. We observed a significant improvement in exercise tolerance, as shown by increased 6-minute walk distance after 3, 6, and 12 months of treatment (increases of 20, 67, and 95 m, respectively). All patients showed an improvement in functional class. The results of echocardiography did not reveal statistically significant differences in systolic pulmonary arterial pressure between baseline and 6 or 12 months of treatment. No significant adverse effects were observed, although sildenafil treatment was suspended in 1 patient due to persistent headache.. The results of this study confirm that sildenafil is an effective drug for the management of pulmonary arterial hypertension and inoperable chronic thromboembolic pulmonary hypertension both in the short term and medium to long term, and that the drug is well tolerated and shows few side effects.

Topics: Adolescent; Adult; Aged; Child; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Piperazines; Pulmonary Embolism; Purines; Sildenafil Citrate; Sulfones; Vasodilator Agents

Sildenafil has a well established pulmonary vasodilatory effect, but has seldom been used in critically ill patients. We report a case of severe recurrent pulmonary embolism in which sildenafil was used as a rescue therapy.. After oral administration of 50 mg of sildenafil, cardiac index increased from 2.11/min/m(2) to 3.21/min/m(2); mean pulmonary artery pressure decreased from 56 mmHg to 46 mmHg, and pulmonary vascular resistance index decreased from 700 dynes/cm(-5)/m(2) to 425 dynes/cm(-5)/m(2), without reduction of arterial systemic pressure. Clinical condition also improved during the following days under treatment of 50 mg sildenafil three times daily.. These observations should stimulate studies with sildenafil in the ICU setting. Sildenafil is easy to administer in every ICU and at any time. If its potential is confirmed, it may be a life-saving drug in some emergency situations caused by severe pulmonary hypertension.

Topics: Female; Humans; Middle Aged; Piperazines; Pulmonary Embolism; Purines; Severity of Illness Index; Sildenafil Citrate; Sulfones; Switzerland; Treatment Outcome; Vasodilator Agents

Sildenafil attenuates acute pulmonary embolism (APE)-induced pulmonary hypertension. However, the hemodynamic effects of sildenafil in combination with other vasodilators during APE have not been examined yet. In the present study, we examined the hemodynamic effects of combined diethylenetriamine/nonoate (DETA-NO, 1microMol kg(-1), i.v.) and sildenafil (0.25mg/kg, i.v.) in an anesthetized dog model of APE. Plasma nitrite/nitrate (NO(x)) and cyclic GMP concentrations were determined using an ozone-based chemiluminescence assay and a commercial enzyme immunoassay, respectively. We found that this dose of DETA-NO did not attenuate APE-induced pulmonary hypertension. However, significant decreases in mean pulmonary artery pressure were observed 15, 30 and 45min after the administration of sildenafil alone or after the combined administration of DETA-NO and sildenafil (all P<0.05). No significant differences among groups were observed in the respiratory parameters. While DETA-NO significantly increased NO(x) concentrations by approximately 4microM, cyclic GMP concentrations increased only when sildenafil was administered (all P<0.05). These results show that the combined administration of 1microMol kg(-1) of DETA-NO and sildenafil is not advantageous compared with sildenafil alone, thus suggesting that sildenafil alone produced maximum attenuation of APE-induced pulmonary hypertension, as far as the NO-cGMP pathway is concerned.

Topics: Animals; Blood Pressure; Cyclic GMP; Disease Models, Animal; Dogs; Drug Interactions; Female; Heart Rate; Hemodynamics; Male; Nitrates; Nitric Oxide Donors; Nitrites; Piperazines; Pulmonary Artery; Pulmonary Embolism; Purines; Respiration; Sildenafil Citrate; Sulfones; Time Factors; Vascular Resistance

Topics: Humans; Phosphodiesterase Inhibitors; Piperazines; Pulmonary Embolism; Purines; Sildenafil Citrate; Sulfones

Selective pulmonary vasodilators attenuate acute pulmonary embolism (APE)-induced pulmonary hypertension. We examined the effects of intravenous sildenafil on the hemodynamic and respiratory changes caused by APE in anesthetized dogs. Sham operated animals (n=3) received only saline infusions. APE was induced by intravenous injections of microspheres in amounts adjusted to increase mean pulmonary artery pressures (MPAP) by 20 mmHg. Hemodynamic evaluation was performed and arterial blood samples were drawn for blood gas analysis at baseline, 15 and 30 min after APE was induced, and then 15, 30, and 45 min after the sildenafil infusion (1 mg kg(-1) infused intravenously in 15 min followed by 0.3 mg kg(-1) h(-1) for 30 min) started in the Sildenafil group (n=7), or saline infusion started in the control group (n=8). APE induced sustained pulmonary hypertension and 325% increase in pulmonary vascular resistance index (PVRI) without significant changes in the other hemodynamic parameters. While the animals in the control group showed no further changes in MPAP and PVRI, a significant decrease in MPAP and PVRI (-25 and -45%, respectively; P<0.05 both) was observed with sildenafil. No significant changes in the other hemodynamic parameters were observed in both groups. APE decreased PaO2, whereas sildenafil attenuated the decrease in PaO2 (P<0.05). We conclude that intravenous sildenafil can selectively attenuate the increases in MPAP and PVRI after APE.

Topics: Animals; Dogs; Female; Heart Rate; Hypertension, Pulmonary; Infusions, Intravenous; Male; Phosphodiesterase Inhibitors; Piperazines; Pulmonary Embolism; Purines; Sildenafil Citrate; Sulfones; Vascular Resistance

Acute pulmonary embolism (APE) is a major cause of pulmonary hypertension and death. We examined the effects of sildenafil on the hemodynamic changes caused by APE in anesthetized dogs. Sham-operated dogs (n = 3) received only saline. APE was induced by stepwise IV injections of 300 mum microspheres in amounts adjusted to increase mean pulmonary artery pressures by 20 mm Hg. Hemodynamic evaluation was performed at baseline, after APE was induced, and then after sildenafil 0.25 mg/kg (n = 8), or sildenafil 1 mg/kg + 0.3 mg . kg(-1) . h(-1) (n = 8) or saline (n = 9) infusions were started. Similar experiments were conducted to examine the effects of sildenafil in rat isolated perfused lung preparation. Plasma thiobarbituric acid reactive species were also determined in both studies to measure oxidative stress. Both doses of sildenafil reduced mean pulmonary artery pressures in dogs by approximately 8 to 16 mm Hg (both P < 0.05) and attenuated the increase in oxidative stress after APE. Mean arterial blood pressure remained unaltered after both doses of sildenafil. Sildenafil produced similar effects after APE in rat isolated perfused lung preparation. These findings indicate that IV sildenafil can selectively attenuate the increases in mean pulmonary artery pressures after APE, possibly through antioxidant mechanisms.

Topics: Acute Disease; Animals; Blood Pressure; Dogs; Female; Hemodynamics; Hypertension, Pulmonary; Male; Malondialdehyde; Oxidative Stress; Phosphodiesterase Inhibitors; Piperazines; Pulmonary Artery; Pulmonary Embolism; Purines; Rats; Rats, Wistar; Sildenafil Citrate; Sulfones; Thiobarbituric Acid Reactive Substances; Vasodilator Agents

Sildenafil attenuates acute pulmonary embolism-induced pulmonary hypertension. However, the hemodynamic effects of sildenafil in combination with other vasodilators during acute pulmonary embolism have not been examined yet. In the present study, we examined the hemodynamic effects of combined sildenafil (0.25 mg/kg, i.v.) and L-arginine (100, 200, 500, and 1000 mg/kg/h, i.v.) in an anesthetized dog model of acute pulmonary embolism. Plasma nitrite/nitrate (NO(x)) and cGMP concentrations were determined using an ozone-based chemiluminescence assay and a commercial enzyme immunoassay, respectively. We found that L-arginine alone did not attenuate acute pulmonary embolism-induced pulmonary hypertension. However, significant decreases in mean pulmonary artery pressure were observed 30, 45, 60, and 75 min after the administration of sildenafil alone or after the combined administration of sildenafil and L-arginine (all P < 0.05). No significant differences among groups were observed in the respiratory parameters. While L-arginine significantly increased NO(x) concentrations, cGMP concentrations increased only when sildenafil was administered (all P < 0.05). These results suggest that while sildenafil attenuates acute pulmonary embolism-induced pulmonary hypertension, L-arginine does not enhance the beneficial hemodynamic effects of sildenafil. In addition, these findings suggest that stimulation of NO synthesis with L-arginine during acute pulmonary embolism does not produce beneficial effects.

Topics: Acute Disease; Analysis of Variance; Animals; Arginine; Blood Pressure; Cyclic GMP; Dogs; Female; Heart Rate; Hypertension, Pulmonary; Infusions, Intravenous; Male; Nitrates; Nitrites; Piperazines; Pulmonary Artery; Pulmonary Embolism; Purines; Respiration; Sildenafil Citrate; Sulfones; Time Factors; Vasodilator Agents

Only a small percentage of patients with chronic thromboembolic pulmonary hypertension are eligible for pulmonary thrombendarterectomy. We investigated the effects of oral sildenafil on hemodynamics and exercise capacity in 12 nonoperable chronic thromboembolic pulmonary hypertension patients. All patients were in disease progression despite sufficient long-term anticoagulation and the best supportive care and suffered from severe pulmonary hypertension (pulmonary vascular resistance index 1,935 +/- 228 dyn. s. cm-5. m2, cardiac index 2.0 l. min-1. m-2, 6-minute walking distance 312 +/- 30 m). After approximately 6 months of sildenafil treatment, pulmonary hemodynamics and exercise capacity improved significantly (pulmonary vascular resistance index 1,361 +/- 177 L. min-1. m2, p = 0.004, cardiac index 2.4 +/- 0.2 L. min-1. m-2, p = 0.009, 6-minute walking distance 366 +/- 28 m, p = 0.02). Therefore, oral sildenafil may offer a new option for medical treatment of this devastating disease.

Topics: Female; Humans; Hypertension, Pulmonary; Male; Phosphodiesterase Inhibitors; Piperazines; Pulmonary Embolism; Purines; Sildenafil Citrate; Sulfones; Time Factors