sildenafil-citrate and Thromboembolism

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

Relative area change (RAC) of the proximal pulmonary artery is a measurement of pulmonary artery distensibility and has been shown to correlate with vasoreactivity studies in patients with idiopathic pulmonary arterial hypertension. We have previously noted a relationship between invasive hemodynamic vasoreactivity testing and long-term response to sildenafil in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). We therefore set out to determine whether RAC can provide useful correlatory non-invasive data.. Patients recruited to a randomized, controlled trial (RCT) of sildenafil at 40 mg 3 times daily underwent additional magnetic resonance imaging (MRI) at the baseline of the trial. Eighteen patients had an MRI that led to a diagnosis of inoperable distal CTEPH or significant residual CTEPH post-operatively. The primary end-point was improvement in 6-minute walk test (6MWT) with secondary end-points of right heart catheterization-based hemodynamics, N-terminal pro-brain natriuretic peptide (NT pro-BNP) and functional class. RAC assessed by MRI was correlated with trial end-points.. Fourteen subjects with baseline MRI completed the protocol. RAC was the only baseline variable that correlated at 1 year to the primary end-point of improvement in 6MWT (r = 0.7, p = 0.006), and also to a change in NT pro-BNP (r = 0.59, p = 0.03). Using a cut-off of RAC over 20% there was an 87.5% sensitivity (95% confidence interval [CI]: 45% to 100%) and a 66.7% specificity (95% CI: 22% to 96%) for an improvement in 6MWT of >40 meters.. RAC correlates with functional response to sildenafil, as measured by the 6MWT, and improved heart function, as measured by NT pro-BNP. RAC shows potential in understanding and possibly predicting treatment response.

Topics: Adult; Aged; Cardiac Catheterization; Chronic Disease; Female; Heart; Hemodynamics; Humans; Hypertension, Pulmonary; Magnetic Resonance Imaging; Male; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Piperazines; Pulmonary Artery; Purines; Recovery of Function; Sensitivity and Specificity; Sildenafil Citrate; Single-Blind Method; Sulfones; Thromboembolism; Time Factors; Treatment Outcome; Vasodilator Agents; Walking

Although surgery is the treatment of choice for CTEPH, it is not appropriate for patients with surgically inaccessible distal disease. These patients are traditionally managed supportively, but may benefit from newer, more specific vasoactive therapies. This study examines the acute haemodynamic responses to inhaled nitric oxide (iNO) and intravenous sildenafil in this patient population.. Nine patients with de novo distal CTEPH and nine with persistent pulmonary hypertension post-pulmonary endarterectomy (PEA) were enrolled. At right heart catheterisation, following baseline haemodynamic measurements, iNO was administered at 20 ppm for 10 min. Following repeat measurements, iNO was discontinued with a subsequent washout period of 10 min. Sildenafil was then administered intravenously at two doses, to achieve plasma levels equivalent to 25 mg and 50 mg orally, with further measurements obtained at the end of each infusion.. Significant reductions in mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR) were demonstrated following both iNO (-4.3 mm Hg or -10.3% p=0.001 and -101 dyn/s/cm(5) or -15.6% p<0.001) and sildenafil (-7.4 mm Hg or -16.9% p<0.001 and -188.8 dyn/s/cm(5) or -25.1% p<0.001). Individual mPAP and cardiac output (CO) responses to iNO and sildenafil correlated well, but haemodynamic changes following sildenafil were consistently more marked. There was, however, no difference in effect between the two doses of sildenafil. Although sildenafil caused significant reductions in systemic vascular resistance, the net haemodynamic effect of sildenafil remained pulmonary selective. Subgroup analysis suggested that post-PEA patients were more responsive to both iNO and sildenafil than de novo patients.. Although all but one patient failed to fulfil the formal haemodynamic response criteria typically used in idiopathic pulmonary arterial hypertension (IPAH), subjects displayed significant acute responses to both iNO and sildenafil suggesting that increased vascular tone forms an important component of distal CTEPH. It is possible that these acute haemodynamic responses may translate to improved clinical outcomes, and thus further long term trials of sildenafil in distal CTEPH are warranted.

Topics: Administration, Inhalation; Adult; Antihypertensive Agents; Blood Pressure; Cardiac Output; Chronic Disease; Drug Therapy, Combination; Female; Humans; Hypertension, Pulmonary; Injections, Intravenous; Male; Middle Aged; Nitric Oxide; Piperazines; Pulmonary Circulation; Purines; Sildenafil Citrate; Sulfones; Thromboembolism; Treatment Outcome; Vascular Resistance; Vasodilation; Vasodilator Agents

For chronic thromboembolic pulmonary hypertension not amenable to pulmonary endarterectomy, effective medical therapy is desired. In an open-label uncontrolled clinical trial, 104 patients (mean +/- sem age 62 +/- 11 yrs) with inoperable chronic thromboembolic pulmonary hypertension were treated with 50 mg sildenafil t.i.d. At baseline, patients had severe pulmonary hypertension (pulmonary vascular resistance 863 +/- 38 dyn.s.cm(-5)) and a 6-min walking distance of 310 +/- 11 m. Eight patients were in World Health Organization functional class II, 76 in class III and 20 in class IV. After 3 months' treatment, there was significant haemodynamic improvement, with reduction of pulmonary vascular resistance to 759 +/- 62 dyn.s.cm(-5). The 6-min walking distance increased significantly to 361 +/- 15 m after 3 months' treatment, and to 366 +/- 18 m after 12 months' treatment. A subset of 67 patients received a single dose of 50 mg sildenafil during initial right heart catheterisation. The acute haemodynamic effect of this was not predictive of long-term outcome. In this large series of patients with inoperable chronic thromboembolic pulmonary hypertension, open-label treatment with sildenafil led to significant long-term functional improvement. The acute effect of sildenafil may not predict the long-term outcome of therapy.

Topics: Adult; Aged; Aged, 80 and over; Cardiac Catheterization; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Piperazines; Purines; Sildenafil Citrate; Statistics, Nonparametric; Sulfones; Thromboembolism; Treatment Outcome; Vascular Resistance; Vasodilator Agents

Topics: Heart-Assist Devices; Hemolysis; Humans; Pulmonary Circulation; Sildenafil Citrate; Thromboembolism

Topics: Heart-Assist Devices; Hemolysis; Humans; Pulmonary Circulation; Sildenafil Citrate; Thromboembolism

Low-level hemolysis (LLH) after left ventricular assist device implantation contributes to thromboembolic events (TE). Free plasma hemoglobin (fHb) scavenges nitric oxide (NO), which causes endothelial dysfunction and activates platelets. fHb also interacts with von Willebrand factor (vWF). We hypothesized that improved hemodynamic and enhanced NO signaling in HeartMate II (HMII) patients with LLH taking the phosphodiesterase-5 inhibitor sildenafil may reduce the risk of TE.From 2011 to 2015, 83 patients underwent HMII implantation. Patients with LLH as defined by elevated lactate dehydrogenase (400 < LDH ≤ 700 U/L) at hospital discharge were identified. Patients were categorized into 4 groups: 1) LLH + sildenafil, 2) LLH no sildenafil, 3) no LLH + sildenafil, and 4) no LLH no sildenafil. Adverse event-free survival was compared between the groups.Thirty-four patients (40.9%) were discharged with LLH and 22 (64.7%) of them took sildenafil. LDH and fHb remained significantly elevated in both LLH groups compared to the no LLH patients (P < 0.0001). Overall incidence of pump thrombosis (PT) was 4.8% and of ischemic stroke (IS) was 8.4%. HMII patients with LLH not on sildenafil had higher risk of TE (hazard ratio (HR): 14.4, 95%-CI: 1.8-117.1, P = 0.001). vWF activity and bleeding incidence did not differ between the LLH and no LLH patients. Mean pulmonary artery pressure and pulmonary vascular resistance decreased significantly in HMII taking sildenafil (P < 0.0001) while cardiac index increased (P < 0.0001).Sildenafil treatment among HMII patients with LLH reduced the risk of thromboembolic events and significantly improved and decompressed the pulmonary circulation during HMII support.

Topics: Aged; Case-Control Studies; Female; Follow-Up Studies; Heart-Assist Devices; Hemolysis; Humans; Male; Middle Aged; Phosphodiesterase 5 Inhibitors; Postoperative Complications; Pulmonary Circulation; Retrospective Studies; Sildenafil Citrate; Thromboembolism; Treatment Outcome

Patients with inoperable chronic thromboembolic pulmonary hypertension (Inop-CTEPH) treated with conventional therapy have a poor survival. We compare the 3-year survival between those treated with conventional therapy and those treated with conventional therapy and a combination of novel drugs. We also evaluate the clinical course. A total of 34 Inop-CTEPH consecutive patients were evaluated from 1991 to 2009 including right heart catheterization (RHC) and perfusion lung scan (PLS): 7 underwent surgical treatment while 27 were confirmed inoperable. Of these 27 patients, 12 evaluated from 1991 to 2003 (Group 1) were treated with conventional therapy and 15 evaluated from 2004 to 2009 (Group 2) were treated with conventional and novel therapies. At baseline, no group difference emerged at RHC. Based on clinical course, novel drugs and oxygen supplementation were given to patients of Group 2. Seven of these who had worse clinical course repeated RHC and four of them also PLS during therapy. Those without repeat RHC had baseline pulmonary artery mean pressure and brain natriuretic peptide (NT-proBNP) lower and mixed venous saturation (SvO2) and exercise test higher (p = 0.022, 0.015, 0.044 and 0.003, respectively). During therapy, those with repeat RHC had total pulmonary vascular resistance reduced (p = 0.012), base excess increased (p = 0.002) and significant redistribution of pulmonary blood flow at PLS. At the 3-year follow-up, survival was 86% in Group 2 and 31% in Group 1 (p = 0.031). In Inop-CTEPH patients, the clinical course may help to select drugs and the level of oxygen supply that can improve hemodynamics, gas exchange and long-term survival.

Topics: Acid-Base Equilibrium; Aged; Antihypertensive Agents; Blood Gas Analysis; Bosentan; Cardiac Output; Chronic Disease; Drug Therapy, Combination; Exercise Test; Female; Humans; Hypertension, Pulmonary; Isoxazoles; Male; Middle Aged; Oxygen Consumption; Oxygen Inhalation Therapy; Piperazines; Purines; Severity of Illness Index; Sildenafil Citrate; Sulfonamides; Sulfones; Survival Rate; Thiophenes; Thromboembolism; Treatment Outcome; Vascular Resistance; Vasodilator Agents

The treatment of pulmonary arterial hypertension (PAH) in pregnancy is reviewed.. PAH is a disease characterized by narrowing of the pulmonary arteries and increased vascular resistance. Women with PAH should avoid becoming pregnant, as the physiological, cardiovascular, and pulmonary changes that occur during pregnancy can exacerbate the condition. However, several viable treatment options are available to improve the outcomes in this patient population, including inhaled nitric oxide, calcium-channel blockers, targeted pulmonary vasodilators, and sildenafil. Epoprostenol, a naturally occurring prostaglandin and vasodilator, is a pregnancy category B drug. Reproductive studies in rats and rabbits have found no impaired fertility or fetal harm at 2.5-4.8 times the recommended human dosage of epoprostenol. Most of the published case reports describe initiating epoprostenol 2-4 ng/kg/min i.v. several weeks before or near the time of delivery. Iloprost is a pregnancy category C drug but has demonstrated benefit in pregnant patients with PAH, with no congenital abnormalities and no postpartum maternal or infant mortality reported. Sildenafil causes vasodilation of the pulmonary vascular bed and vasodilation in the systemic circulation. Two case reports have described the successful treatment with sildenafil, a pregnancy category B drug, of pregnant patients with PAH. Patients with idiopathic PAH or chronic thromboembolic PAH should receive full-dose subcutaneous low-molecular-weight heparin therapy instead of warfarin for bleeding prophylaxis during pregnancy.. Targeted pulmonary vasodilators are viable treatment options for pregnant patients with PAH. Early recognition and management of worsening symptoms are essential to improve outcomes for both the mother and infant.

Topics: Epoprostenol; Female; Humans; Hypertension, Pulmonary; Iloprost; Piperazines; Pregnancy; Pregnancy Complications, Cardiovascular; Purines; Sildenafil Citrate; Sulfones; Thromboembolism; Vasodilator Agents

We describe the case of a 30-year-old female patient with chronic thromboembolic pulmonary hypertension that has an excellent functional capacity under treatment with sildenafil. She did an exercise stress echocardiography that revealed marked right ventricular dilatation during exercise. This information was used for clinical decision and the authors discuss the potential utility of this echocardiographyc sign.

Topics: Adult; Antihypertensive Agents; Bosentan; Cardiac Catheterization; Dilatation, Pathologic; Echocardiography, Doppler; Exercise Test; Female; Humans; Hypertension, Pulmonary; Piperazines; Purines; Sildenafil Citrate; Sulfonamides; Sulfones; Thromboembolism; Vascular Resistance; Vasodilator Agents; Ventricular Dysfunction, Right