Graded balloon dilation atrial septostomy in severe primary pulmonary hypertension. A therapeutic alternative for patients nonresponsive to vasodilator treatment

A modelling study of atrial septostomy for pulmonary arterial hypertension, and its effect on the state of tissue oxygenation and systemic blood flow

Atrial septostomy is performed in patients with severe pulmonary arterial hypertension, and has been shown to improve symptoms, quality of life and survival. Despite recognized clinical benefits, the underlying pathophysiologic mechanisms are poorly understood. We aimed to assess the effects of right-to-left shunting on arterial delivery of oxygen, mixed venous content of oxygen, and systemic cardiac output in patients with pulmonary arterial hypertension and a fixed flow of blood to the lungs. We formulated equations defining the mandatory relationship between physiologic variables and delivery of oxygen in patients with right-to-left shunting. Using calculus and computer modelling, we considered the simultaneous effects of right-to-left shunting on physiologies with different pulmonary flows, total metabolic rates, and capacities for carrying oxygen. Our study indicates that, when the flow of blood to the lungs is fixed, increasing right-to-left shunting improves systemic cardiac output, arterial blood pressure, and arterial delivery of oxygen. In contrast, the mixed venous content of oxygen, which mirrors the average state of tissue oxygenation, remains unchanged. Our model suggests that increasing the volume of right-to-left shunting cannot compensate for right ventricular failure. Atrial septostomy in the setting of pulmonary arterial hypertension, therefore, increases the arterial delivery of oxygen, but the mixed systemic saturation of oxygen, arguably the most important index of tissue oxygenation, stays constant. Our data suggest that the clinically observed beneficial effects of atrial septostomy are the result of improved flow of blood rather than augmented tissue oxygenation, provided that right ventricular function is adequate.

Non-congenital heart disease associated pediatric pulmonary arterial hypertension

Recognition of causes of pulmonary hypertension other than congenital heart disease is increasing in children. Diagnosis and treatment of any underlying cause of pulmonary hypertension is crucial for optimal management of pulmonary hypertension. This article discusses the available knowledge regarding several disorders associated with pulmonary hypertension in children: idiopathic pulmonary arterial hypertension (IPAH), pulmonary capillary hemangiomatosis, pulmonary veno-occlusive disease, hemoglobinopathies, hepatopulmonary syndrome, portopulmonary hypertension and HIV. Three classes of drugs have been extensively studied for the treatment of IPAH in adults: prostanoids (epoprostenol, treprostinil, iloprost, beraprost), endothelin receptor antagonists (bosentan, sitaxsentan, ambrisentan), and phosphodiesterase inhibitors (Sildenafil, tadalafil). These medications have been used in treatment of children with pulmonary arterial hypertension, although randomized clinical trial data is lacking. As pulmonary vasodilator therapy in certain diseases may be associated with adverse outcomes, further study of these medications is needed before widespread use is encouraged.

Potts anastomosis for children with idiopathic pulmonary hypertension

Mortality in children with idiopathic pulmonary arterial hypertension is high, emphasizing the need for novel therapeutic approaches. A surgical approach consisting in the creation of anastomosis between descending aorta and left pulmonary artery, the Potts shunt, has been proposed to decompress right ventricle. We reported two cases of severe idiopathic pulmonary hypertension in children with right heart failure refractory to medical treatment who benefited of Potts shunt.

Updated evidence-based treatment algorithm in pulmonary arterial hypertension

Uncontrolled and controlled clinical trials with different compounds and procedures are reviewed to define the risk-benefit profiles for therapeutic options in pulmonary arterial hypertension (PAH). A grading system for the level of evidence of treatments based on the controlled clinical trials performed with each compound is used to propose an evidence-based treatment algorithm. The algorithm includes drugs approved by regulatory agencies for the treatment of PAH and/or drugs available for other indications. The different treatments have been evaluated mainly in idiopathic PAH, heritable PAH, and in PAH associated with the scleroderma spectrum of diseases or with anorexigen use. Extrapolation of these recommendations to other PAH subgroups should be done with caution. Oral anticoagulation is proposed for most patients; diuretic treatment and supplemental oxygen are indicated in cases of fluid retention and hypoxemia, respectively. High doses of calcium-channel blockers are indicated only in the minority of patients who respond to acute vasoreactivity testing. Nonresponders to acute vasoreactivity testing or responders who remain in World Health Organization (WHO) functional class III, should be considered candidates for treatment with either an oral phosphodiesterase-5 inhibitor or an oral endothelin-receptor antagonist. Continuous intravenous administration of epoprostenol remains the treatment of choice in WHO functional class IV patients. Combination therapy is recommended for patients treated with PAH monotherapy who remain in WHO functional class III. Atrial septostomy and lung transplantation are indicated for refractory patients or where medical treatment is unavailable.

Treatment of pediatric pulmonary hypertension

Pulmonary hypertension was once thought to be a rare condition and only managed in specialized centers. Now however, with the advent of echocardiography, it is found in many clinical scenarios, in the neonate with chronic lung disease, in the acute setting in the intensive care unit, in connective tissue disease and in cardiology pre- and postoperatively. We have a better understanding of the pathological process and have a range of medication which is starting to be able to palliate this previously fatal condition. This review describes the areas that are known in this condition and those that are less familiar. The basic physiology behind pulmonary hypertension and pulmonary vascular disease is explained. The histopathologic process and the various diagnostic tools are described and are followed by the current and future therapy at our disposal.

A modified technique of stent fenestration of the interatrial septum improves patients with pulmonary hypertension

AIMS

A significant number of patients with pulmonary hypertension are resistant to medical therapy. We wanted to evaluate whether the modified technique of stent fenestration of the interatrial septum would be feasible and safe, and offer clinical benefit.

METHODS AND RESULTS

The medical records of all patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension who underwent a stent fenestration of the interatrial septum between 2001 and 2008 were reviewed. In all fifteen patients (12 female, mean age 48.2 +/- 20.5 years) a successful fenestration procedure could be performed. Median follow-up time between diagnosis and fenestration was 2.3 years (range from 0.5 to 18.6 years). Mean event free survival since diagnosis and after septostomy was 9.8 +/- 2.9 and 3.2 +/- 0.8 years, respectively. When one extreme outlier was excluded, the 6 min walk distance improved significantly from 309 +/- 69 m immediately before fenestration to 374 +/- 84 m, 3-4 months after fenestration (n = 8, paired t-test, P = 0.03). No stent occlusion occurred.

CONCLUSION

The modified stent fenestration technique is feasible and safe in patients with severe pulmonary hypertension. In a selected group of patients, functional capacity might improve although disease progression continues.

Pulmonary hypertension: diagnosis and management

Pulmonary arterial hypertension is a progressive, symptomatic, and ultimately fatal disorder for which substantial advances in treatment have been made during the past decade. Effective management requires timely recognition and accurate diagnosis of the disorder and appropriate selection among therapeutic alternatives. Despite progress in treatment, obstacles remain that impede the achievement of optimal outcomes. The current article provides an overview of the pathobiologic mechanisms of pulmonary arterial hypertension, including genetic substrates and molecular and cellular mechanisms, and describes the clinical manifestations and classification of pulmonary arterial hypertension. The article also reviews established approaches to evaluation and treatment, with emphasis on the appropriate application of calcium channel blockers, prostacyclin analogues, endothelin receptor antagonists, and phosphodiesterase 5 inhibitors. In addition, the authors discuss unresolved issues that may complicate patient management, such as the clinical importance of mild or exercise-related pulmonary arterial hypertension, and they identify avenues by which treatment may advance in the future through the use of combination treatment, outcomes assessment, and exploration of alternative pharmacologic strategies.

Pulmonary hypertension: diagnosis and management

Pulmonary arterial hypertension is a progressive, symptomatic, and ultimately fatal disorder for which substantial advances in treatment have been made during the past decade. Effective management requires timely recognition and accurate diagnosis of the disorder and appropriate selection among therapeutic alternatives. Despite progress in treatment, obstacles remain that impede the achievement of optimal outcomes. The current article provides an overview of the pathobiologic mechanisms of pulmonary arterial hypertension, including genetic substrates and molecular and cellular mechanisms, and describes the clinical manifestations and classification of pulmonary arterial hypertension. The article also reviews established approaches to evaluation and treatment, with emphasis on the appropriate application of calcium channel blockers, prostacyclin analogues, endothelin receptor antagonists, and phosphodiesterase 5 inhibitors. In addition, the authors discuss unresolved issues that may complicate patient management, such as the clinical importance of mild or exercise-related pulmonary arterial hypertension, and they identify avenues by which treatment may advance in the future through the use of combination treatment, outcomes assessment, and exploration of alternative pharmacologic strategies.

Major pulmonary embolism and hemodynamic stability from shunting through a patent foramen ovale

While the combination of a patent foramen ovale (PFO) and thromboembolic disease is thought to portend increased morbidity and mortality, PFO presence in the setting of major pulmonary embolism (PE) may serve as a means to rescue patients from immediate hemodynamic collapse and death. We present two patients with major pulmonary embolism and right-to-left shunting consistent with PFO as seen on transthoracic echocardiography. In the setting of major PE, PFO may prevent acute right ventricular failure by acting as a 'pop-off' valve, alleviating increased ventricular pressures; but concomitantly portend deleterious effects in the form of paradoxical embolism and intractable hypoxemia.

Review: Therapeutic advances in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction, in situ thrombosis, and vascular remodeling of small pulmonary arteries inducing increased pulmonary arterial resistance. Conventional treatment is based on life style modification and nonspecific treatment (warfarine, diuretics, oxygen). Calcium channel blockers are vasodilatators that have been shown to be of great efficacy in a very specific subpopulation of patients with PAH. For the majority of patients, specific PAH therapies are still lacking. Numerous studies evaluating prostacyclin agonists, endothelin-receptor antagonists, and phosphodiesterase type 5 inhibitors are now available to guide therapeutic choices. Despite those important advances there is still no cure for PAH. Fortunately, research is ongoing and many drugs show promises.

Cardiovascular consequences of pulmonary hypertension

Pulmonary hypertension occurs when pulmonary vascular pressures are elevated. Pulmonary arterial hypertension is associated with occlusion of the pulmonary arterial tree, while pulmonary venous hypertension is seen when pulmonary vein outflow is impeded. Cardiovascular consequences are common with pulmonary hypertension, regardless of the underlying pathogenesis and whether management is complex. However, there are a number of interventions that may improve quality of life and survival of pulmonary hypertension. This article discusses current recommendations for diagnosis and management.

Efficacy and long-term patency of fenestrated amplatzer devices in children

INTRODUCTION

Novel transcatheter techniques to control interatrial communications exist. Devices with restrictive fenestrations can be implanted to maintain patency of an atrial septostomy, or reduce an interatrial communication. Experience with these devices in children is limited.

PATIENTS AND METHODS

Fenestrated atrial septal devices were implanted into 10 children (5 male, age 1.5-15.5 years). Devices were modified by the manufacturer (MM, n = 6), or by a modification of an atrial septal occlusion device by the operator (OM, n = 4). Seven devices were implanted after atrial septal puncture and septostomy for severe symptomatic pulmonary hypertension (PHT) [4 heart failure, 3 syncope], according to World Health Organisation Guidelines. Two devices were implanted to reduce left to right shunting through large atrial septal defects with associated PHT. One device was implanted acutely to offload the left atrium during extracorporal circulatory support prior to heart transplantation. Warfarin (n = 5), aspirin (n = 4), or heparin (n = 1) were used for prevention of fenestration thrombosis.

RESULTS

Symptoms in all patients with PHT improved after implantation; syncope recurred with fenestration occlusion in one patient. Nine patients were followed up to a mean of 26 months. Five devices (all MM; warfarin n = 4, aspirin n = 1) remained patent on echocardiography. Fenestrations occluded in 4 children after median follow-up of 10 months (MM n = 1, OM n = 3, warfarin n = 1, aspirin n = 3).

CONCLUSIONS

Implantation of fenestrated atrial devices is feasible and effective; but the occlusion rate is high. Further research on fenestrated atrial septal devices with better long-term patency, and effective antithrombotic drug treatment is necessary.

Implantation of stents to ensure an adequate interatrial communication in patients with hypoplastic left heart syndrome

AIMS

To assess the feasibility of interatrial stenting for left atrial decompression in infants with hypoplastic left heart syndrome treated by a "hybrid-approach", with bilateral surgical banding of the pulmonary arteries and percutaneous stenting of the arterial duct.

PATIENTS AND METHODS

We stented the atrial septum in 5 infants aged from 21 to 77 days, making the intervention as an elective procedure in 4, but as a rescue procedure in the fifth patient, who had a restrictive foramen. The stents, comprising 2 Jo-stents of 17 millimetres hand-crimped on a balloon catheter with dimensions of 10 by 20 millimetres, and 3 premounted Genesis stents with dimensions of 10 by 19 millimetres, were placed using a 6 French long or short sheath by femoral venous access. The stents were expanded under fluoroscopic guidance to create a slightly diabolo-shaped form that fitted the septum.

RESULTS

The percutaneous interventions were successfully performed in all cases, producing significant improvement in clinical condition after placement. The saturations of oxygen increased from an average of 64% plus or minus 18% to 88% plus or minus 7%, (p < 0.05). During a mean follow up of 2.5 months, without any anticoagulant therapy, there were no complications related to the stenting. Surgical removal of the stents was uneventful during reconstruction of the aortic arch and creation of a bidirectional cavopulmonary connection in 4 patients, and during cardiac transplantation in one.

CONCLUSION

In the context of the hybrid approach, definitive decompression of the left atrium can be achieved by stenting the atrial septum in infants with hypoplastic left heart syndrome. Placement of the stents is safe and effective, with insertion in the form of a diabolo reducing the risk of dislocation, as well as embolisation of the stent.

Management strategies for patients with pulmonary hypertension in the intensive care unit

OBJECTIVE

Pulmonary hypertension may be encountered in the intensive care unit in patients with critical illnesses such as acute respiratory distress syndrome, left ventricular dysfunction, and pulmonary embolism, as well as after cardiothoracic surgery. Pulmonary hypertension also may be encountered in patients with preexisting pulmonary vascular, lung, liver, or cardiac diseases. The intensive care unit management of patients can prove extremely challenging, particularly when they become hemodynamically unstable. The objective of this review is to discuss the pathogenesis and physiology of pulmonary hypertension and the utility of various diagnostic tools, and to provide recommendations regarding the use of vasopressors and pulmonary vasodilators in intensive care.

DATA SOURCES AND EXTRACTION

We undertook a comprehensive review of the literature regarding the management of pulmonary hypertension in the setting of critical illness. We performed a MEDLINE search of articles published from January 1970 to March 2007. Medical subject headings and keywords searched and cross-referenced with each other were: pulmonary hypertension, vasopressor agents, therapeutics, critical illness, intensive care, right ventricular failure, mitral stenosis, prostacyclin, nitric oxide, sildenafil, dopamine, dobutamine, phenylephrine, isoproterenol, and vasopressin. Both human and animal studies related to pulmonary hypertension were reviewed.

CONCLUSIONS

Pulmonary hypertension presents a particular challenge in critically ill patients, because typical therapies such as volume resuscitation and mechanical ventilation may worsen hemodynamics in patients with pulmonary hypertension and right ventricular failure. Patients with decompensated pulmonary hypertension, including those with pulmonary hypertension associated with cardiothoracic surgery, require therapy for right ventricular failure. Very few human studies have addressed the use of vasopressors and pulmonary vasodilators in these patients, but the use of dobutamine, milrinone, inhaled nitric oxide, and intravenous prostacyclin have the greatest support in the literature. Treatment of pulmonary hypertension resulting from critical illness or chronic lung diseases should address the primary cause of hemodynamic deterioration, and pulmonary vasodilators usually are not necessary.

Congenital diaphragmatic hernia and associated cardiovascular malformations: type, frequency, and impact on management

The co-occurrence of congenital diaphragmatic hernia (CDH) and cardiovascular malformations (CVMs) has important clinical, genetic, and developmental implications. Previous examinations of this topic often included patients with genetic syndromes. To correct this potential bias, we undertook an extensive review of the literature and obtained new data. The frequency of CVMs associated with isolated CDH was 11-15%. A careful analysis of CVMs indicates that atrial and ventricular septal defects, conotruncal defects, and left ventricular outflow tract obstructive defects were the most common type of CVMs, but proportional to the frequency of occurrence in the general population. The combination of CVM and CDH results in a poorer prognosis than would be expected with either malformation alone. However, the impact on survival from patients with a genetic syndrome has not been consistently evaluated. We encourage researchers to re-analyze existing series and recommend that future studies distinguish isolated CDH from that which is associated with other malformations, especially as part of genetic syndromes. Therapies should be tailored to maximize cardiac output and systemic oxygen delivery rather than systemic oxygen saturation alone. Although there is speculation about the frequency with which isolated left ventricular "hypoplasia" occurs in patients with CDH, we suggest it results from compression of a pre-load deficient left ventricle by the hypertensive right ventricle, and unlike true hypoplasia, is reversible. Irrespective of the type of severity of CVMs in patients with CDH, the degree of pulmonary hypoplasia and pulmonary vascular disease predicts outcome.

Pulmonary hypertension: current diagnosis and treatment

Pulmonary hypertension (PH) is a devastating disease that - if untreated - is characterized by a poor prognosis. According to the current classification (Venice, 2003), pulmonary arterial hypertension (PAH) is distinguished from other forms of PH. Recent advances in drug therapy have led to a dramatic improvement of medical care particularly in patients with PAH. Hence, early establishment of the diagnosis appears increasingly important. This review article gives an overview on the definition, classification, pathophysiology, and clinical presentation of various forms of PH. Furthermore, it summarizes the recommended diagnostic work-up and the current treatment options particularly in PAH, with special emphasis on prostanoids, endothelin receptor antagonists (ERAs), and phosphopdiesterase type 5 (PDE5) inhibitors such as sildenafil. Finally, novel developments are being discussed which currently represent an exciting field of research.

Atrial Septostomy Decreases Sympathetic Overactivity in Pulmonary Arterial Hypertension

BACKGROUND

We have reported previously that the sympathetic nervous system is activated in patients with pulmonary arterial hypertension (PAH), and that this is only partly explained by a decrease in arterial oxygenation. Possible causes for increased muscle sympathetic nerve activity (MSNA) in patients with PAH include right atrial distension and decreased cardiac output. Both may be improved by atrial septostomy, but this intervention also further decreases arterial oxygenation. In the present study, we wanted to investigate the effect of atrial septostomy on MSNA in patients with PAH.

METHODS

We recorded BP, heart rate (HR), arterial O2 saturation (SaO2), and MSNA before and after atrial septostomy in PAH patients (mean [+/- SE] age, 48 +/- 5 years) and in closely matched control subjects. Measurements were also performed after septostomy, while SaO2 was brought to the preprocedure level by supplemental O2 therapy.

RESULTS

Compared to the control subjects (n = 10), the PAH patients (n = 11) had a lower mean BP (75 +/- 2 vs 96 +/- 3 mm Hg, respectively; p < 0.001), lower mean SaO2 (92 +/- 1% vs 97 +/- 0%, respectively; p < 0.001), increased mean HR (84 +/- 4 vs 68 +/- 3 beats/min; p < 0.01), and markedly increased mean MSNA (76 +/- 5 vs 29 +/- 2 bursts per minute; p < 0.001). Atrial septostomy decreased mean SaO2 (to 85 +/- 2%; p < 0.001) and mean MSNA (to 69 +/- 4 bursts per minute; p < 0.01), but did not affect HR or BP. Therapy with supplemental O2 did not affect MSNA, BP, or HR. The decrease in MSNA was correlated to the decrease in right atrial pressure (r = 0.62; p < 0.05).

CONCLUSIONS

Atrial septostomy in PAH patients decreases sympathetic hyperactivity despite an associated decrease in arterial oxygenation, and this appears to be related to decreased right atrial distension.

Surgical therapies for pulmonary arterial hypertension

Surgical therapies for the treatment of pulmonary arterial hypertension typically are reserved for patients who are deemed to be refractory to medical therapy and have evidence of progressive right-sided heart failure. Atrial septostomy, a primarily palliative procedure, may stave off hemodynamic collapse from right-sided heart failure long enough to permit a more definitive surgical treatment such as lung or combined heart-lung transplantation. This article discusses indications for and results of atrial septostomy and lung and heart-lung transplantation in patients who have pulmonary arterial hypertension.

Atrial septostomy in treatment of end-stage right heart failure in patients with pulmonary hypertension

BACKGROUND

Right ventricular (RV) failure is the main cause of death in patients with pulmonary hypertension (PH). Balloon atrial septostomy (BAS) is believed to relieve symptoms of PH by increasing systemic flow and reducing RV preload.

METHODS

Fourteen BAS procedures were performed in 11 patients (5 men and 6 women; mean [+/- SD] age, 33 +/- 12 years) with RV failure in the course of PH that was refractory to conventional treatment. BAS consisted of a puncture of the interatrial septum and subsequent dilatations with balloons of increasing diameter in a step-by-step manner.

RESULTS

After BAS, the mean oxygen saturation of aortic blood decreased (before, 93 +/- 4%; after, 84 +/- 4%; p = 0.001), while mean cardiac index increased (before, 1.54 +/- 0.34 L/min/m(2); after, 1.78 +/- 0.35 L/min/m(2); p = 0.001), resulting in a positive trend for mean systemic oxygen transport (before, 270 +/- 64 mL/min; after, 286 +/- 81 mL/min; p = 0.08). Pulmonary vascular resistance (PVR) slightly increased immediately after the procedure, and this rise inversely correlated with mixed venous blood partial oxygen pressure both before BAS (r = -0.69; p = 0.009) and after BAS (r = -0.64; p = 0.018). Mean functional class improved from 3.2 +/- 0.4 to 2.6 +/- 0.7 (p = 0.03) after 1 month. At follow-up (mean time to follow-up, 8.1 +/- 6.2 months; range, 0.8 to 20.2 months), seven patients died and two underwent lung transplantation. There was no difference in the survival rate compared to that obtained from National Institutes of Health equation. A significant size reduction in the created defect was observed in six patients, requiring repeat BAS procedures in three cases.

CONCLUSIONS

The current BAS technique improves cardiac index and functional class without significant periprocedural complications, except for a transient increase in PVR related to acute desaturation of mixed venous blood. At long-term follow-up, a high incidence of spontaneous decrease in orifice size has been observed.

Atrial septostomy improves survival in select patients with pulmonary hypertension

BACKGROUND

Atrial septostomy is a palliative treatment for patients with pulmonary hypertension (PHTN) refractory to vasodilator therapy. Limited data exist in the pediatric population and in patients with repaired congenital heart defects.

METHODS

We performed a retrospective analysis of hemodynamic and symptomatic changes in patients with PHTN who underwent an atrial septostomy at our institution.

RESULTS

Forty-six atrial septostomies were performed on 43 patients. Patient ages ranged from 0.3 to 30 years (median 12.5). Of 43 patients, 29 had primary PHTN, 10 had PHTN associated with repaired congenital heart defects, and 4 had other secondary causes of PHTN. Mean baseline pulmonary vascular resistance was 35 +/- 17 Wood units, and mean pulmonary artery pressure was 74 +/- 19 mm Hg. Patients surviving > or = 30 days had immediate improvement in cardiac index (from 2.3 to 2.9 L x min(-1) x m(-2), P < .0001), right atrial pressure (RAp) (from 9.9 to 8.3 mm Hg, P < .05), and oxygen delivery (from 424 to 491 mL O2 per minute, P < .01), with a decrease in systemic oxygen saturation (from 93% to 86%, P < .001). Pulmonary artery pressure was unchanged (P = .3). New York Heart Association class and symptoms of syncope improved (P < .01). Event-free survival at 1, 2, and 3 years was 84%, 77%, and 69%, respectively. Using the National Institutes of Health Registry model, predicted survival probability significantly improved (P < .001). Ten patients (22%) died within 30 days of catheterization. Mortality was associated with preceding decompensations in the intensive care unit (6/10, P < .001) and a higher RAp (21.4 vs 9.8 mm Hg, P < .001).

CONCLUSIONS

Atrial septostomy provides symptomatic and hemodynamic improvement in cardiac index and RAp. Risk of septostomy is increased in patients with preceding decompensation or a RAp > 18 mm Hg.

Postoperative management of the patient undergoing pulmonary endarterectomy

The postoperative care of the patient undergoing pulmonary endarterectomy presents challenges that occur not only with other types of cardiac surgery but also with significant respiratory system changes related to alterations in pulmonary blood flow. Postoperative mortality associated with this procedure has declined substantially over the years as a consequence of improved evaluative procedures and selective surgical referral, advances in surgical technique, and an understanding of the unique postoperative complications that may occur. However, postoperative acute lung injury and residual pulmonary hypertension continue to represent major causes of mortality associated with this procedure and represent areas where additional investigative efforts are necessary. Here we describe the unique hemodynamic and respiratory changes that occur in the postoperative pulmonary endarterectomy patient and an evidence-based approach to their optimal management.

Assessment and treatment of pulmonary arterial hypertension: an Australian perspective in 2006

Pulmonary arterial hypertension is a group of diseases which forms a small subset of those with elevated pulmonary artery pressure (pulmonary hypertension). The recent development of selective pulmonary vasodilator has lead to a substantial resurgence of interest in what have been previously regarded as rare and incurable diseases. This review aims to describe the spectrum of pulmonary vascular diseases, the evolving understanding as to pathogenesis, the evolving evidence of efficacy for drug therapies, trying to put this into a contemporary Australian context. Several key pathogenic pathways may be involved: prostacycline, Nitric Oxide-cGMP-phosphodiesterase 5 and endothelin- all of which are exploited for therapeutic benefit by newly available drug therapies. A recently modified classification system reasserts the importance of precise diagnosis. The cardinal symptom of exertional dyspnea warrants careful evaluation in an attempt to prevent (frequently occurring) substantial delay in diagnosis. Echocardiogram is the cornerstone of screening for pulmonary arterial hypertension; however, a detailed evaluation including a carefully performed right heart catheterisation with sufficient data to allow calculation of pulmonary vascular resistance is key to accurate diagnosis. These new approaches to therapy are already substantially improving quality of life and prognosis.

Pulmonary arterial hypertension

Better recognition of primary pulmonary hypertension can produce better treatment by comprehensive therapists.

Migraine with aura following atrial septostomy for pulmonary arterial hypertension

BACKGROUND

A 34-year-old woman with known familial pulmonary arterial hypertension presented with syncope. Despite medical therapy with an endothelin-receptor antagonist and a phosphodiesterase inhibitor, the patient had NYHA class III symptoms, with exertional dyspnea. Right heart catheterization revealed severe pulmonary hypertension (right atrial pressure 15 mmHg, right ventricular pressure 80/15 mmHg, pulmonary artery pressure 80/35 mmHg, mean pulmonary artery pressure 52 mmHg). The patient underwent balloon atrial septostomy, creating a right-to-left shunt. Although she had no history of headaches or migraine attacks, the patient developed a migraine headache with aura on the third day after the procedure. Migraine attacks recurred for the next 2 days, but symptoms were relieved with simple analgesia.

INVESTIGATIONS

Physical examination, electrocardiography, laboratory testing, 6-min-walk test, right heart catheterization, chest radiography, transesophageal echocardiography, transthoracic echocardiography.

DIAGNOSIS

Migraine with aura following atrial septostomy.

MANAGEMENT

Bosentan, sildenafil, furosemide, spironolactone and warfarin therapy, atrial septostomy, and paracetamol therapy for migraine.

Use of Amplatzer fenestrated atrial septal defect device in a child with familial pulmonary hypertension

In a 4.5-year-old child with refractory pulmonary arterial hypertension, we performed atrial septostomy with the application of an Amplatzer fenestrated device designed to maintain patency. Continuous intravenous epoprostenol infusion was started concomitantly. Forty-two months after the procedure, the patient had no recurrent syncope and remained in New York Heart Association functional class II. Fenestration of the atrial septum is feasible in children with pulmonary artery hypertension. No conclusion regarding the patient's need for an atrial septal defect can be drawn since concomitant prostanoid therapy was administered. The long-term patency of the atrial communication needs further confirmation and the optimal timing for its application has to be determined.

Management of heart failure with pulmonary hypertension

Heart failure (HF) and pulmonary hypertension (PH) coexist frequently and contribute to each other. Because PH often is an insidious disease, the cornerstone of management is the early identification and treatment of its underlying causes, such as left-sided heart disease, left to right shunts, and pulmonary disorders. A practical clinical classification has been proposed by the Third World Symposium on Pulmonary Arterial Hypertension for the purpose of diagnosis and treatment of PH. Thromboembolic pulmonary hypertension should always be considered. Recent studies using vasodilators such as prostacyclins and endothelin antagonists give new hope in the otherwise poor prognosis of idiopathic pulmonary arterial hypertension and its related conditions. Despite optimum medical management, transplantation (lung/heart-lung) remains the choice in severely symptomatic patients.

Pediatric lung transplantation

Lung transplantation in children has been performed since the early 1990s. The indications are cystic fibrosis, pulmonary vascular disease, and a variety of other pulmonary problems leading to death in small children. These other diseases include abnormalities in the metabolism of surfactant producing severe respiratory insufficiency in newborn infants. Many problems accompany these patients before transplantation and many problems are produced both by the transplant itself and immunosuppressant drugs which these children are obliged to take following transplantation. Nonetheless, lung transplantation offers the only real hope of survival in many instances. The long-term results have been somewhat discouraging with a 5-year survival of approximately 50%. The major causes of mortality late following lung transplantation are bronchiolitis obliterans, infections, and malignancy. The development of newer immunosuppressant drugs may offer hope for better results in the future.

Insertion of a Fenestrated Amplatzer Atrial Septostomy Device for Severe Pulmonary Hypertension

Atrial septostomy is a palliative treatment for severe pulmonary hypertension. We report the insertion of a novel custom-made fenestrated Amplatzer atrial septostomy device following repeat atrial septostomy for severe pulmonary hypertension in a terminally ill patient with scleroderma resulting in 6 months of palliation.

Reliable atrial septostomy by stenting of the atrial septum

The aim of this report was to describe our experience with creating an interatrial communication by stenting the interatrial septum. In many forms of congenital heart disease, the presence of an appropriate interatrial shunt is critical. After the first several weeks of life, balloon atrial septostomy is not effective, and success with other methods is limited. Clinical records, echocardiograms, and catheterization data in patients who had an atrial septal stent placed between 2001 and 2004 at UCLA were reviewed. Changes in atrial pressures and systemic saturations were analyzed. Follow-up data and explant pathology were reviewed as available. Thirteen patients had stenting of the atrial septum (four restrictive, nine nonrestrictive). In patients with elevated right and left atrial pressures, there was a mean reduction of 2.4 and 7.4 mm Hg in right atrial and left atrial pressures, respectively. In patients with transposition physiology, there was a mean increase in oxygen saturation of 11.3%. Follow-up echocardiograms revealed patent stents with excellent position relative to the atrial septum. In six cases, the stents were removed during subsequent surgery and appeared endothelialized and patent. Stenting of the atrial septum is safe and effective in selected cases, allowing for a reliable, long-lasting, restrictive or nonrestrictive interatrial communication.

Atrial septostomy using a butterfly stent in a patient with severe pulmonary arterial hypertension

We describe a patient with severe pulmonary artery hypertension and refractory right heart failure who underwent "butterfly" stent atrial septostomy guided by intracardiac ultrasound. This technique may be superior to previously reported blade and balloon septostomy because it allows creation of an atrial septal defect of a precise predetermined diameter. The patient's systemic blood flow and clinical status improved significantly after the procedure, allowing her to be accepted as a candidate for lung transplantation.

Pulmonary arterial hypertension

Pulmonary arterial hypertension is a disease of the small pulmonary arteries characterized by vascular narrowing and increased pulmonary vascular resistance, which eventually leads to right ventricular failure. Vasoconstriction, vascular proliferation, remodeling of the pulmonary vessels, and thrombosis are all contributing factors to the increased vascular resistance seen in this disease. Pulmonary arterial hypertension develops as a sporadic disease (idiopathic), as an inherited disorder (familial), or in association with certain conditions (collagen vascular diseases, portal hypertension, human immunodeficiency virus infection, congenital systemic-to-pulmonary shunts, ingestion of drugs or dietary products, or persistent fetal circulation). The pathogenesis of pulmonary arterial hypertension is a complicated, multifactorial process. It seems doubtful that any one factor alone is sufficient to activate the necessary pathways leading to the development of this disease. Rather, clinically apparent pulmonary arterial hypertension most likely develops after a second insult occurs in an individual who is already susceptible owing to genetic factors, environmental exposures, or acquired disorders. Currently, there is no cure for pulmonary arterial hypertension but several novel therapeutic options are now available that can improve symptoms and increase survival.

Role of atrial septostomy in the treatment of children with pulmonary arterial hypertension

OBJECTIVES

To assess in retrospect the safety and effectiveness of atrial septostomy in children with severe pulmonary arterial hypertension without an intracardiac communication.

METHODS

20 patients were reviewed retrospectively, 19 with idiopathic pulmonary arterial hypertension. The mean age at septostomy was 8.4 years (range 3 months to 17 years). Graded balloon septostomy alone was carried out in eight patients, a blade septostomy was done in two, a blade septostomy plus graded balloon septostomy was done in three, and a fenestrated device was inserted in seven.

RESULTS

There were no fatalities. Four children suffered complications during the procedure. None had further syncope and all improved symptomatically with a significant (p < 0.01) decrease in World Health Organization functional class (mean shift -0.6) and a significant improvement in the semiquantitative echocardiographic assessment of right ventricular function (p < 0.03). The mean oxygen saturation decreased by 7.8 percentage points. The atrial communication closed in two children, necessitating a repeat procedure. After a mean follow up of 2.1 years (range one month to 6.7 years), 18 of 20 children are still alive.

CONCLUSION

Atrial septostomy improved symptoms and quality of life in a group of children deteriorating with severe pulmonary arterial hypertension. This procedure is to be recommended for severely symptomatic children, before they become critically ill. Fenestrated devices may help ensure indefinite patency of the atrial communication.

Traitement de l’hypertension artérielle pulmonaire

Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction, in situ thrombosis, and vascular remodeling of small pulmonary arteries. It induces a fixed pulmonary arterial obstruction, persistent elevation of pulmonary arterial resistance, and eventually right heart failure. Conventional therapy is based on simple measures (exercise limitation) and nonspecific treatments (warfarin, diuretics, and oxygen). Pure vasodilators, such as calcium channel blockers, are effective only in a minority of patients who have an acute response to vasodilator testing. Intravenous prostacyclin (epoprostenol) and endothelin receptor blockers have vasodilator and antiproliferative properties. Epoprostenol therapy has significantly improved PAH prognosis and remains the first-line treatment for patients with the most severe disease. Bosentan is an interesting first-line treatment for NYHA functional class III patients. Availability of novel specific drugs (endothelin receptor type A antagonists, prostacyclin analogues, type 5 phosphodiesterase inhibitors) is opening new perspectives in PAH treatment. The long-term benefit of these drugs remains to be evaluated and their respective place in treatment of these patients is still uncertain. The evolution of therapy from vasodilators to antiproliferative agents reflects the advancement in our understanding of the mechanisms mediating pulmonary arterial hypertension.