Factors that influence the outcome of primary pulmonary hypertension

How severity and classification of pulmonary hypertension affect pregnancy outcomes: a systematic review and timeline

Women with pulmonary hypertension (PH) have increased mortality during pregnancy and the peripartum period. An increasing number of publications suggest improvements in maternal outcomes, so we conducted a systematic review focusing on disease severity and maternal survival. After screening 9097 potential studies from 1967 to 2021, we identified 66 relevant publications. Outcomes improved continuously over time and mortality fell from 11.6% in studies published before 2015 to 8.2% in studies published after 2015. Mortality was lower in patients with mild disease (0.8%) than in those with Eisenmenger syndrome (26.2%) or idiopathic pulmonary arterial hypertension (7.4-24.0%). One major drawback of the published studies is that they define severity using echocardiographic-estimated pulmonary artery pressures, without considering more contemporary parameters. This systematic review provides new insights for preconception counseling on pregnancy risks related to PH and suggests that PH classification and severity should be carefully considered in determining an individual's pregnancy-associated risk.

Short-term study of atrial shunt and improvement of functional mitral regurgitation

BACKGROUND

This study used an atrial septal shunt to compare the treatment progress and prognosis for patients with heart failure (HF) who have different ejection fractions.

METHODS

Twenty HF patients with pulmonary hypertension, who required atrial septal shunt therapy, were included in this study. The patients underwent surgery between December 2012 and December 2020. They were divided into two groups based on their ejection fraction: a group with reduced ejection fraction (HFrEF) and a group with preserved ejection fraction(HFpEF) + mid-range ejection fraction (HfmrEF). Echocardiography was utilized to evaluate parameters such as left ventricular dimension (LVD), left ventricular ejection fraction (LVEF), and left ventricular end-diastolic volume (LVEDV). Hemodynamic parameters were measured using cardiac catheterization. The patient's cardiac function was assessed using the six-minute walking test (6MWT), KCCQ score, NYHA classification, and the degree of functional mitral regurgitation (FMR). Followed-up visits were conducted at 1, 3, and 6 months, and any adverse effects were recorded.

RESULTS

The LVEF values were consistently higher in the HFpEF+HFmrEF group than HFrEF group at all periods (P < 0.05). Differences in LVD were observed between the two groups before the surgery. Statistically, significant differences were found at the preoperative stage, 1 month, and 3 months (P < 0.05, respectively). However, the LVEDV showed a significant difference between the two groups only at 3 months (P = 0.049). Notably, there were notable variations in LAPm, LAPs, and the pressure gradient between the LA-RA gradient at baeline, after implantation, and during the 6 months follow-up (all P < 0.05).

CONCLUSION

Following treatment, the HFpEF+HFmrEF group exhibited more significant improvements in echocardiographic and cardiac catheterization indices than the HFrEF group. However, there was no statistically significant difference between the two groups regarding the 6MWT and KCCQ scores. It is important to note that the findings of this study still require further investigation in a large sample size of patients.

Is combined use of radiofrequency ablation and balloon dilation the future of interatrial communications?

INTRODUCTION

Personalized and stable interatrial communication is an important palliative therapy for patients with heart failure. However, this remains a technically challenging task.

AREAS COVERED

In the past decades, substantial advancements in atrial septostomy for the creation of controllable and durable interatrial communication have been made, and numerous novel devices and techniques are in various stages of development. In this review, we discuss the evolving indications for atrial septostomy, current approaches with or without device implantation, and indicators for optimal interatrial communication. The combined use of radiofrequency ablation and balloon dilation (CURB) is an individualized management approach based on underlying hemodynamics, which demonstrates unique advantages in creating a sufficient interatrial communication with satisfactory stability. The advantages and disadvantages of this implant-free procedure are analyzed and its clinical prospects are assessed.

EXPERT OPINION

With ready availability, high safety, and efficacy, CURB is a promising procedure for creating personalized and stable interatrial communication without device implantation. Further research is required to simplify the procedure, screen optimal reference parameters for personalized therapy, and evaluate the long-term outcome in a large population of patients.

Epidemiology and management of right ventricular-predominant heart failure and shock in the cardiac intensive care unit

Cardiogenic shock from left ventricular failure is a common presentation in the intensive care unit. In contrast, right ventricular (RV)-predominant heart failure (HF) causing shock is less well recognized. We review the epidemiology and mechanisms of RV-predominant HF and discuss pharmacologic and device-based approaches for the management of this challenging clinical problem.

Mechanistic Insights into Tricuspid Regurgitation Secondary to Pulmonary Arterial Hypertension

The simultaneous presence of pulmonary arterial hypertension (PAH) and secondary tricuspid regurgitation (STR) portends particularly poor outcomes. However, not all patients with PAH develop significant STR, and the mechanisms and clinical implications underlying this phenomenon remain unclear. We sought to describe the functional, anatomic, hemodynamic, and clinical characteristics of patients with PAH with and without STR. Patients diagnosed with PAH between 2007 and 2013 were included. STR, defined by absent primary tricuspid valve disease on transthoracic echocardiogram, was considered significant if ≥ moderate in severity. The characteristics of right-sided chambers and tricuspid valve annuli and leaflets were compared between patients with significant versus nonsignificant STR using a transthoracic echocardiogram, cardiac computed tomography, and right-sided cardiac catheterization. These features were then correlated with the composite outcome of all-cause mortality and PAH hospitalization. Of 88 included patients, 52 had significant STR. No baseline clinical differences, including atrial fibrillation, were observed. Patients with significant STR had worse right ventricular dysfunction (tricuspid annular planar systolic excursion = 1.5 vs 2.1 cm; p = 0.02) and increased right ventricular sphericity (sphericity index = 1.8 vs 2; p = 0.004), with similar annular dimensions/shape, lengths/angles of the mural and septal leaflets, and tenting height. After a median of 54 months, right atrial mean pressure was independently associated with the composite outcome on multivariable analysis (hazard ratio = 1.07, p = 0.02). In conclusion, anatomic and functional alterations in the right ventricle rather than the tricuspid valve are implicated in developing significant STR in PAH. Multimodality imaging provides mechanistic insight, and hemodynamic assessment may offer prognostic guidance in this population.

Beyond transplant: Roles of atrial septostomy and Potts shunt in pediatric pulmonary hypertension

Despite significant successes in treating children with pulmonary hypertension, many still die from their disease. Death most often results from right ventricular failure. Bilateral lung transplantation has historically been the ultimate palliation for children who develop heart failure despite maximal medical therapy. Creating an atrial level shunt has been advocated as a pre-transplant intervention to help reduce symptoms and perhaps serve as a bridge to transplant. More recently, the utilization of a pulmonary-to-systemic anastomosis, that is, Potts shunt, has demonstrated efficacy in ameliorating symptoms in children with severe, progressive disease. This improvement is often coincident with a reduction in expensive and onerous pulmonary hypertension specific medications. Improvement has been sustained over the years in some children, delaying the need for transplant consideration. Research is ongoing to determine more specific risks/benefits of using the Potts shunt in children with pulmonary hypertension both in the short term and long.

Balloon atrial septostomy as initial therapy in pediatric pulmonary hypertension

Balloon atrial septostomy is a palliative procedure currently used to bridge medically refractory pulmonary hypertension patients to lung transplantation. In the current report, we present balloon atrial septostomy as an initial therapy for high-risk pediatric pulmonary hypertension patients at our institution. Nineteen patients with median age of 4.3 years (range 0.1–14.3 years) underwent balloon atrial septostomy during initial admission for pulmonary hypertension. There were no procedural complications or deaths within 24 h of balloon atrial septostomy. Patients were followed for a median of 2.6 years (interquartile range 1.0–4.8 years). Three (16%) patients died, 3 (16%) underwent lung transplantation, and 1 (5%) underwent reverse Potts shunt. Transplant-free survival at 30 days, 1 year, and 3 years was 84%, 76%, and 67% respectively. This single-center experience suggests early-BAS in addition to pharmacotherapy is safe and warrants consideration in high-risk pediatric pulmonary hypertension patients.

Management of Pulmonary Arterial Hypertension

Purpose of Review

This review focuses on the therapeutic management and individualized approach to Group 1 pulmonary arterial hypertension (PAH), utilizing Food and Drug Administration-approved PAH-specific therapies and various interventional and surgical options for PAH.

Recent Findings

The paradigm for the optimal management of PAH has shifted in recent years. Upfront combination therapy with an endothelin receptor antagonist and a phosphodiesterase 5 inhibitor is now widely accepted as standard of care. In addition, there is increasing emphasis on starting prostanoids early in order to delay time to clinical worsening. However, less is known regarding which prostanoid agent to initiate and the optimum time to do so. In order to facilitate shared decision-making, there is an increasing need for decision tools based on guidelines and collective clinical experiences to navigate between pharmacologic and interventional treatments, as well as explore innovative, therapeutic pathways for PAH.

Summary

The management of PAH has become increasingly complex. With a growing number of PAH-specific therapies, intimate knowledge of the therapeutics and the potential barriers to adherence are integral to providing optimal care for this high-risk patient population. While current PAH-specific therapies largely mediate their effects through pulmonary vasodilation, ongoing research efforts are focused on ways to disrupt the mechanisms leading to pulmonary vascular remodeling. By targeting aberrations identified in the metabolism and proliferative state of pulmonary vascular cells, novel PAH treatment pathways may be just on the horizon.

Percutaneous closure of residual shunting in a patient with a fenestrated atrial septal defect occluder: A case report

RATIONALE

Fenestrated atrial septal defect (ASD) occlusion has been performed in patients complicated with severe pulmonary hypertension (PH). Nevertheless, the persistent interatrial residual shunting in the fenestration might increase the risk of paradoxical embolism. Percutaneous closure of fenestrated ASD occluder (ASO) has not yet been reported.

PATIENT CONCERNS

A 26-year-old patient with a 25-mm ASD and severe PH underwent ASD closure using a Memory ASO with a waist of 32 and 6-mm custom-made fenestration. Echocardiography revealed the fenestration remained 6 mm and the pulmonary artery pressure decreased to the normal range at the 6-month follow-up.

DIAGNOSES

Persistent interatrial residual shunting in ASO.

INTERVENTIONS

Percutaneous closure of residual interatrial shunting was performed using a waist of 8-mm ASO under guidance of TEE.

OUTCOMES

The fenestration was successfully closed. Neither thromboembolism nor infection events were noted during the 12-month follow-up after the procedure.

LESSONS

This case illustrates that percutaneous closure of the residual shunting in fenestrated ASO was feasible and safe for short- and long-term.

Creation of a restrictive atrial communication in pulmonary arterial hypertension (PAH): effective palliation of syncope and end-stage heart failure

Atrial septostomy (AS) is recommended for pulmonary arterial hypertension (PAH)-associated right ventricular (RV) failure, recurrent syncope, or pulmonary hypertensive crisis (PHC). We aimed to evaluate the feasibility and efficacy of AS to manage PAH from infancy to adulthood. From June 2009 to December 2016, transcatheter atrial communications were created in 11 PAH patients (4 girls/women; median age = 4.3 years; range = 33 days-26 years; median body weight = 14 kg; range = 3-71 kg; NYHA-/Ross class IV; n = 11). PAH was classified as idiopathic (n = 6) or secondary (n = 5). History of syncope was dominant (n = 6); two with patent foramen ovale (PFO) admitted with recurrent PHC, three patients required resuscitation before AS. Three patients had PAH-associated low cardiac output. The average pulmonary arterial pressures (PAP systolic/diastolic) were 101/50 (±34/23); the corresponding systemic arterial pressures (SAP) were 99/54 (±23/11); and the mean ratio of PAPd / SAPd was 0.97 (±0.4). Percutaneous trans-septal puncture was uneventfully performed in nine patients; a PFO was dilated in two patients. There was no procedure-related mortality. The median balloon size was 10 mm (range = 6-14 mm); the mean catheter time was 174.6 ± 48 min; fluoroscopy time was 19.8 (±11) min. Syncope and PHC were successfully treated in all patients. The mean arterial oxygen saturation decreased from 97 ± 2 to 89 ± 11.7. One patient died awaiting lung transplantation, one continues to be listed; two patients received a reverse Potts-shunt, one patient died during follow-up; seven patients are stable with PAH-specific treatment. Percutaneous AS is an effective method palliating PAH-associated syncope, PHCs or right (bi-) ventricular heart failure.

Cardiopulmonary Resuscitation in Infants and Children With Cardiac Disease: A Scientific Statement From the American Heart Association

Cardiac arrest occurs at a higher rate in children with heart disease than in healthy children. Pediatric basic life support and advanced life support guidelines focus on delivering high-quality resuscitation in children with normal hearts. The complexity and variability in pediatric heart disease pose unique challenges during resuscitation. A writing group appointed by the American Heart Association reviewed the literature addressing resuscitation in children with heart disease. MEDLINE and Google Scholar databases were searched from 1966 to 2015, cross-referencing pediatric heart disease with pertinent resuscitation search terms. The American College of Cardiology/American Heart Association classification of recommendations and levels of evidence for practice guidelines were used. The recommendations in this statement concur with the critical components of the 2015 American Heart Association pediatric basic life support and pediatric advanced life support guidelines and are meant to serve as a resuscitation supplement. This statement is meant for caregivers of children with heart disease in the prehospital and in-hospital settings. Understanding the anatomy and physiology of the high-risk pediatric cardiac population will promote early recognition and treatment of decompensation to prevent cardiac arrest, increase survival from cardiac arrest by providing high-quality resuscitations, and improve outcomes with postresuscitation care.

Increased microvolt T-wave alternans in children and adolescents with Eisenmenger syndrome

Objective:

To determine the values of microvolt T-wave alternans (MTWA) in children and adolescents with Eisenmenger syndrome (ES) and controls.

Methods:

Thirteen were included in the study. After analyzing the 24-h ECG recordings, MTWA was considered using three leads (V5, V1, and aVF). Right heart catheterization and 6-minute walk test (6-MWD) were applied to the patients and pro-brain natriuretic peptide levels were assessed; echocardiographic parameters were obtained from both the groups and the results were compared.

Results:

The MTWA value in lead V5 was 81.08±10.73 µV in the patient group (63.50±18.78 µV in the control group), in lead V1 was 75.00±16.86 µV (73.94±16.77 µV in the control group), and in lead aVF was 73.77±17.81 µV (72.61±16.21 µV in the control group). Comparison of MTWA values between patients and controls revealed that only lead V5 values were statistically different in the ES group. The 6-MWD scores significantly correlated with lead V5. Right atrial volume and right ventricular fractional area change were significantly correlated with lead V1. The Tei index was significantly correlated with lead aVF.

Conclusion:

The MTWA lead V5 value was significantly higher in children with ES than in controls and was also correlated with decreased exercise tolerance.

Interventional Therapies in Pulmonary Hypertension

Despite advances in drug therapy, pulmonary hypertension-particularly arterial hypertension (PAH)-remains a fatal disease. Untreatable right heart failure (RHF) from PAH eventually ensues and remains a significant cause of death in these patients. Lowering pulmonary input impedance with different PAH-specific drugs is the obvious therapeutic target in RHF due to chronically increased afterload. However, potential clinical gain can also be expected from attempts to unload the right heart and increase systemic output. Atrial septostomy, Potts anastomosis, and pulmonary artery denervation are interventional procedures serving this purpose. Percutaneous balloon pulmonary angioplasty, another interventional therapy, has re-emerged in the last few years as a clear alternative for the management of patients with distal, inoperable, chronic thromboembolic pulmonary hypertension. The current review discusses the physiological background, experimental evidence, and potential clinical and hemodynamic benefits of all these interventional therapies regarding their use in the setting of RHF due to severe pulmonary hypertension.

Management of pulmonary hypertension and right heart failure in the intensive care unit

Management of acute right ventricular failure, both with and without coexisting pulmonary hypertension, is a common challenge encountered in the intensive care setting. Both right ventricular dysfunction and pulmonary hypertension portend a poor prognosis, regardless of the underlying cause and are associated with significant morbidity and mortality. The right ventricle is embryologically distinct from the left ventricle and has unique morphologic and functional properties. Management of right ventricular failure and pulmonary hypertension in the intensive care setting requires tailored hemodynamic management, pharmacotherapy, and often mechanical circulatory support. Unfortunately, our understanding of the management of right ventricular failure lags behind that of the left ventricle. In this review, we will explore the underlying pathophysiology of the failing right ventricle and pulmonary vasculature in patients with and without pulmonary hypertension and discuss management strategies based on evidence-based studies as well as our current understanding of the underlying physiology.

Pulmonary Hypertension in Congenital Heart Disease: Beyond Eisenmenger Syndrome

Patients with adult congenital heart disease have an increased risk of developing pulmonary hypertension. There are several mechanisms of pulmonary hypertension in patients with adult congenital heart disease, and understanding them requires a systematic approach to define the patient's hemodynamics and physiology. This article reviews the updated classification of pulmonary hypertension in patients with adult congenital heart disease with a focus on pathophysiology, diagnostics, and the evaluation of pulmonary hypertension in special adult congenital heart disease populations.

Interventional and surgical therapeutic strategies for pulmonary arterial hypertension: Beyond palliative treatments

Despite significant advances in pharmacological treatments, pulmonary arterial hypertension remains an incurable disease with an unreasonably high morbidity and mortality. Although specific pharmacotherapies have shifted the survival curves of patients and improved exercise endurance as well as quality of life, it is also true that these pharmacological interventions are not always accessible (particularly in developing countries) and, perhaps most importantly, not all patients respond similarly to these drugs. Furthermore, many patients will continue to deteriorate and will eventually require an additional, non-pharmacological, intervention. In this review we analyze the role of atrial septostomy and Potts anastomosis in the management of patients with pulmonary arterial hypertension, we summarize the current worldwide clinical experience (case reports and case series), and discuss why these interventional/surgical strategies might have a therapeutic role beyond that of a "bridge" to transplantation.

Atrial Septostomy: A Contemporary Review

Pulmonary arterial hypertension (PAH) is a rare disease, but it boasts significant morbidity and mortality. Although remarkable achievements have been made in the medical treatment of PAH, there is a role for invasive or surgical procedures in patients with progressive disease despite optimal medical therapy or with no access to such therapy. Atrial septostomy creates a right-to-left intracardiac shunt to decompress the overloaded right ventricle. Despite significant advances to validate and improve this palliative procedure, as well as recent reports of improved outcomes, it is only slowly being adopted. This article aims to detail the history, indications, contraindications, procedural techniques, and outcomes of atrial septostomy. We will also shed light on some of the newer interventions, inspired by the same physiological concept, that are being evaluated as potential palliative modalities in patients with PAH.

Balloon dilation atrial septostomy for advanced pulmonary hypertension in patients on prostanoid therapy

BACKGROUND

Prostanoid therapy improves quality of life and may increase survival in patients with advanced pulmonary hypertension (PH). Balloon dilated atrial septostomy (BDAS) can palliate or bridge to transplantation for patients resistant to medical therapy. The safety and efficacy of BDAS in the prostanoid era has not previously been reported.

METHODS

All patients had progressive symptoms despite prostanoid therapy at the time of their first BDAS. Sixteen patients who underwent a total of 23 septostomies between 2004 and 2014 were included in this retrospective case series.

RESULTS

Patients were aged 47.6 years ± 11.3 with 12/16 women. Etiologies included idiopathic (7), methamphetamine (6), scleroderma (1), and anorexigen (2). One patient died within 24 hr post-procedure. Thirty-day and 1-year survival were 75% and 64%, respectively. Six of the septostomies were revisions, including two which were ultimately stented. Three subjects were successfully bridged to transplant. Pulmonary capillary wedge pressure (PCWP) increased from a mean of 13 to 17 mm Hg, cardiac index increased from 2.1 to 2.4 L/min/m(2) , and arterial saturation decreased from 90.7 ± 4.3 to 82.5 ± 5.6%. All non-survivors at 30 days were male and had higher baseline serum creatinine, mean RAP, right ventricular end diastolic pressure (RVEDP), and left ventricle (LV) filling pressures, and lower right ventricle (RV) ejection fraction. Mortality was associated with unchanged post-septostomy cardiac output despite an increase in left ventricular end diastolic pressure (LVEDP).

CONCLUSIONS

BDAS may be an alternate therapy for select PH patients who have symptomatic progression despite prostanoid therapy. Survival is comparable to prior reports of BDAS in the pre-prostanoid era.

Study of clinical, radiological and echocardiographic features and correlation of Qanadli CT index with RV dysfunction and outcomes in pulmonary embolism

BACKGROUND

There are no Indian studies correlating the CT pulmonary embolism index (Qanadli) with right ventricular function and outcome. In the present study we aimed to study the clinical manifestations of patients presenting with acute pulmonary thromboembolism and correlate the radiographic features with echocardiographic features and outcome.

METHODS

Thirty five patients presenting with symptomatic acute pulmonary thromboembolism in between 2011 and 2013 were studied for clinical, radiological and echocardiographic features and outcome (in-hospital & 1 month follow up).

RESULTS

The mean duration of presentation after onset of symptoms was 5.7 ± 3.7 days. Right ventricular dysfunction was observed in 11 (31.4%) patients. Out of 35 patients in whom CT pulmonary angiogram performed, 14 patients had Qanadli PE index >60% of whom 11 (78.6%) patients had right ventricular dysfunction. None had right ventricular dysfunction when PE index was <60% (p < 0.001). There was significant correlation between pulmonary vascular obstruction index and right ventricular dysfunction (p < 0.0001). Nine (25.7%) patients were thrombolysed with Streptokinase. Total mortality including in-hospital and 1 month follow up was 11.4% (4 patients). The mortality in patients with PE index >60% was 21.4% and was nil with <60% (p = 0.02). The mortality in patients with right ventricular dysfunction was 27.2% and was nil without right ventricular dysfunction (p = 0.0075).

CONCLUSION

A PE index which was shown to be a strong independent predictor of right ventricular dysfunction in PE, correlating linearly with different variables associated with higher morbidity and mortality, enabling accurate risk stratification and selection of patients for more aggressive treatment.

2014 Guidelines of Taiwan Society of Cardiology (TSOC) for the Management of Pulmonary Arterial Hypertension

Pulmonary hypertension (PH) is a hemodynamic and pathophysiologic condition, defined as a mean pulmonary arterial pressure exceeding 25 mmHg at rest. According to the recent classifications, it is grouped into pulmonary arterial hypertension (PAH), heart-related, lung-related, thromboembolic, and miscellaneous PH. In the past two decades, tremendous advances have occurred in the field of PH. These include (1) development of clinical diagnostic algorithm and a monitoring strategy dedicated to PAH, (2) defining strong rationales for screening at-risk populations, (3) advent of pulmonary specific drugs which makes PAH manageable, (4) recognition of needs of having proper strategy of combining existing pulmonary specific drugs, and/or potential novel drugs, (5) pursuit of clinical trials with optimal surrogate endpoints and study durations, (6) recognition of critical roles of PH/right ventricular function, as well as interdependence of ventricles in different conditions, especially those with various phenotypes of heart failure, and (7) for rare diseases, putting equal importance on carefully designed observation studies, various registries, etc., besides double blind randomized studies. In addition, ongoing basic and clinical research has led to further understanding of relevant physiology, pathophysiology, epidemiology and genetics of PH/PAH. This guidelines from the working group of Pulmonary Hypertension of the Taiwan Society of Cardiology is to provide updated guidelines based on the most recent international guidelines as well as Taiwan's domestic research on PH. The guidelines are mainly for the management of PAH (Group 1) ; however the majority of content can be helpful for managing other types of PH.

KEY WORDS

Pulmonary arterial hypertension; Taiwan guidelines.

Current clinical management of pulmonary arterial hypertension

During the past 2 decades, there has been a tremendous evolution in the evaluation and care of patients with pulmonary arterial hypertension (PAH). The introduction of targeted PAH therapy consisting of prostacyclin and its analogs, endothelin antagonists, phosphodiesterase-5 inhibitors, and now a soluble guanylate cyclase activator have increased therapeutic options and potentially reduced morbidity and mortality; yet, none of the current therapies have been curative. Current clinical management of PAH has become more complex given the focus on early diagnosis, an increased number of available therapeutics within each mechanistic class, and the emergence of clinically challenging scenarios such as perioperative care. Efforts to standardize the clinical care of patients with PAH have led to the formation of multidisciplinary PAH tertiary care programs that strive to offer medical care based on peer-reviewed evidence-based, and expert consensus guidelines. Furthermore, these tertiary PAH centers often support clinical and basic science research programs to gain novel insights into the pathogenesis of PAH with the goal to improve the clinical management of this devastating disease. In this article, we discuss the clinical approach and management of PAH from the perspective of a single US-based academic institution. We provide an overview of currently available clinical guidelines and offer some insight into how we approach current controversies in clinical management of certain patient subsets. We conclude with an overview of our program structure and a perspective on research and the role of a tertiary PAH center in contributing new knowledge to the field.

Saudi Guidelines on the Diagnosis and Treatment of Pulmonary Hypertension: Medical and surgical management for pulmonary arterial hypertension

Prior to the availability of the pulmonary arterial hypertension (PAH)-specific therapy, PAH was a dreadful disease with a very poor prognosis. Better understanding of the complex pathobiology of PAH has led to a major therapeutic evolution. International regulatory agencies have approved many specific drugs with different pharmacologic pathways and routes of administration. In the year 2013, two new drugs with great potentials in managing PAH have been added to the treatment options, macitentan and riociguat. Additional drugs are expected to come in the near future.

A substantial body of evidence has confirmed the effectiveness of pulmonary arterial hypertension (PAH)-specific therapies in improving the patients’ symptomatic status and slowing down the rate of clinical deterioration.

Although the newer modern medications have significantly improved the survival of patients with PAH, it remains a non-curable and fatal disease. Lung transplantation (LT) remains the only therapeutic option for selected patients with advanced disease who continue to deteriorate despite optimal therapy.

Impact of differential right-to-left shunting on systemic perfusion in pulmonary arterial hypertension

OBJECTIVES

This study aimed at identifying the ideal right-to-left shunt-fraction to improve cardiac output (CO) and systemic perfusion in pulmonary arterial hypertension (PHT).

BACKGROUND

Atrial septostomy (AS) has been a high-risk therapeutic option for symptomatic drug-refractory patients with PHT. Results have been unpredictable due to limited knowledge of the optimal shunt-quantity.

METHODS

In nine dogs, an 8-mm shunt-prosthesis was inserted between the superior vena cava (SVC) and the left atrium. With pulmonary artery (PA) banding, mean (± SEM) systolic right ventricular pressure increased from 37 ± 1 mm Hg at baseline to 44 ± 1 mm Hg (moderate PHT, P = 0.005) and 50 ± 2 mm Hg (severe PHT, P < 0.001). Shunt-flow was adjusted by total (forcing all flow through the shunt) or partial occlusion of the SVC and partial or total clamping of the shunt. Caval-, shunt-, and aortic-flow were measured by ultrasonic flow-probes. Blood gases were drawn from the aortic root and PA.

RESULTS

At severe PHT, a shunt-flow of 11 ± 1% of CO (253 ± 90 mL/min) increased CO significantly by 25% (1.8 ± 0.1 to 2.4 ± 0.2 L/min, P = 0.005) causing an increase of systemic oxygen delivery index (DO2 I) by 23% (309 ± 23 to 399 ± 32 mL/min/m(2), P = 0.035). Arterial O2 -saturation did not change significantly until a shunt-flow of 18 ± 2% was exceeded, causing a drop from 96 ± 1% to 84 ± 4% (P = 0.013). At moderate PHT, CO or DO2 I did not improve significantly at any shunt-flow.

CONCLUSIONS

In severe PHT, a shunt-flow of 11% of CO represented the ideal shunt-fraction. Augmentation of CO compensated for declined O2 -saturation due to right-to-left shunting and improved DO2 I. In moderate PHT, AS is less promising.

Atrial septostomy benefits severe pulmonary hypertension patients by increase of left ventricular preload reserve

At present, it is unknown why patients suffering from severe pulmonary hypertension (PH) benefit from atrial septostomy (AS). Suggested mechanisms include enhanced filling of the left ventricle, reduction of right ventricular preload, increased oxygen availability in the peripheral tissue, or a combination. A multiscale computational model of the cardiovascular system was used to assess the effects of AS in PH. Our model simulates beat-to-beat dynamics of the four cardiac chambers with valves and the systemic and pulmonary circulations, including an atrial septal defect (ASD). Oxygen saturation was computed for each model compartment. The acute effect of AS on systemic flow and oxygen delivery in PH was assessed by a series of simulations with combinations of different ASD diameters, pulmonary flows, and degrees of PH. In addition, blood pressures at rest and during exercise were compared between circulations with PH before and after AS. If PH did not result in a right atrial pressure exceeding the left one, AS caused a left-to-right shunt flow that resulted in decreased oxygenation and a further increase of right ventricular pump load. Only in the case of severe PH a right-to-left shunt flow occurred during exercise, which improved left ventricular preload reserve and maintained blood pressure but did not improve oxygenation. AS only improves symptoms of right heart failure in patients with severe PH if net right-to-left shunt flow occurs during exercise. This flow enhances left ventricular filling, allows blood pressure maintenance, but does not increase oxygen availability in the peripheral tissue.

Pulmonary hypertension-"state of the art" management in 2012

Pulmonary artery hypertension (PAH) is a pathological condition of small pulmonary arteries, characterised by vascular proliferation and remodelling. The pulmonary artery pressure and pulmonary vascular resistance progressively rise, leading to right heart failure and death. Pulmonary artery hypertension may be secondary to various conditions, or it may be idiopathic where no underlying cause is identifiable. Earlier, only symptomatic treatment was available for such patients which did not change the natural history of the disease. However, over the years, improvement in understanding the pathogenesis has resulted in the development of targeted approaches to the treatment of PAH. Survival advantage has also been shown with some of the pharmacologic agents. This review article discusses the current management strategy for PAH with special emphasis on an idiopathic variety, in an Indian context.

Atrial septostomy in patients with pulmonary hypertension: should it be recommended?

Treatment options for patients with advanced pulmonary hypertension (PH) are limited. Iatrogenic creation of an interatrial communication (i.e., atrial septostomy [AS]) has been suggested as a possible treatment option or as a bridge to transplantation in selected patients and has been incorporated into current PH guidelines. Uptake of the procedure has been slow and the worldwide experience with AS is limited to approximately 280 published cases, over a period of more than 25 years. The rationale for creating an AS has been provided by the observation that patients with congenital heart disease, shunt lesions and PH have a better survival compared with patients with idiopathic PH. We review pathophysiologic data and the published clinical experience and discuss the rationale, indication and potential pitfalls of AS in patients with severe PH.

Acute right ventricular failure in the setting of acute pulmonary embolism or chronic pulmonary hypertension: a detailed review of the pathophysiology, diagnosis, and management

The right ventricle (RV) is integral to normal cardiac function, but receives little attention in the medical literature. The etiologic causes of acute RV failure often differ from those encountered in left ventricular dysfunction. Thus, RV failure frequently requires diagnostic procedures and management strategies that differ from those routinely used in the management of intrinsic left ventricular dysfunction. In this summary, the structure and function of the RV will be reviewed, concentrating on the pathophysiologic mechanisms behind the development of RV dysfunction. We will then focus on two distinct populations of patients who are at risk for acute RV failure: those with chronic pulmonary arterial hypertension (PAH) and those with acute pulmonary embolism. In chronic PAH, we will examine clinical circumstances common to hospitalized patients that may provoke acute RV decompensation, as well as pharmacologic therapies that are unique to RV failure management in PAH. Individuals with acute RV failure in the setting of pulmonary embolism represent a group with particularly high mortality, and the specific diagnostic and management strategies that are important for improved survival will be discussed.

Usefulness of right-to-left shunting and poor exercise gas exchange for predicting prognosis in patients with pulmonary arterial hypertension

We hypothesized that the longitudinal changes in peak oxygen uptake, ventilatory efficiency, and exercise-induced right-to-left shunting in patients with pulmonary arterial hypertension (PAH) would predict outcomes better than baseline measurements alone. Patients with PAH die prematurely. Identifying prognostic markers is critical for treating patients with PAH; however, longitudinal prognostic information of PAH is limited. We enrolled 103 patients with PAH into a long-term, prospective outcome study using serial cardiopulmonary exercise testing to measure the peak oxygen uptake, ventilatory efficiency (ratio of ventilation to carbon dioxide output at the anaerobic threshold), right-to-left shunting, and other factors in patients treated with optimal therapy. The patients were followed up for a mean of 4.7 years. During the study period, 20 patients died, and 3 underwent lung transplantation. The baseline peak oxygen uptake and ventilatory efficiency was 0.79 L/min and 49 (normal <34), respectively, reflecting severe disease. Poorer ventilatory efficiency and greater New York Heart Association classification were associated with poor outcome at baseline and at follow-up. On multivariate analysis, the persistence or development of an exercise-induced right-to-left shunt strongly predicted death or transplantation (p <0.0001), independent of the hemodynamics and all other exercise measures, including peak oxygen uptake and ventilatory efficiency. The absence of a shunt at baseline was associated with a 20% rate of nonsurvival, which decreased to 7% at follow-up. A poorer ventilatory efficiency appeared to be associated with a poor outcome in patients without a shunt. In conclusion, a persistent exercise-induced right-to-left shunt and poor ventilatory efficiency were highly predictive of poor outcomes in patients with pulmonary arterial hypertension.

Measuring the heart in pulmonary arterial hypertension (PAH): implications for trial study size

PURPOSE

To calculate the sample size for a theoretical pulmonary arterial hypertension (PAH) randomized controlled trial (RCT) by using cardiovascular magnetic resonance (CMR) imaging to determine the repeatability of measures between two scans.

MATERIALS AND METHODS

Two same-day examinations from 10 PAH patients were analyzed manually and semiautomatically. Study size was calculated from the standard deviation (SD) of repeatability. Different approaches to right-ventricle (RV) mass were investigated, agreement between methods tested and interobserver reproducibility measured by Bland-Altman analysis to explore how the PAH heart might be best measured.

RESULTS

Repeatability was good for almost all manually-measured indices but poor for semiautomated measurement of RV mass and left-ventricle (LV) end-diastolic volume (EDV). Thus, for an RCT (power, 80%; significance level, 5%) analyzing "outcome" indices (RVEDV, LVEDV, RV ejection fraction, and RV mass; anticipated change: 10 mL, 10 mL, 3%, and 10 g, respectively) manually, 34 patients are required compared to 78 if analysis is semiautomated. RV mass was repeatable if the interventricular septum was divided between ventricles or if wholly apportioned to the LV. Limits of agreement between manual and semiautomated analyses were unsatisfactory for RV measures and interobserver reproducibility was worse for semiautomated than manual analysis.

CONCLUSION

Manual is more robust than semiautomated analysis and at present should be favored in RCTs in PAH as it leads to lower sample size requirements.

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.

Interatrial shunt for chronic pulmonary hypertension: differential impact of low-flow vs. high-flow shunting

The purpose of the present study was to determine for the first time the qualitative and quantitative impact of varying degrees of interatrial shunting on right heart dynamics and systemic perfusion in subjects with chronic pulmonary hypertension (CPH). Eight dogs underwent 3 mo of progressive pulmonary artery banding, following which right atrial and ventricular end-systolic and end-diastolic pressure-volume relations were calculated using conductance catheters. An 8-mm shunt prosthesis was inserted between the superior vena cava and left atrium, yielding a controlled model of atrial septostomy. Data were obtained 1) preshunt or "CPH"; 2) "Low-Flow" shunt; and 3) "High-Flow" shunt (occluding superior vena cava forcing all flow through the shunt). With progressive shunting, right ventricular pressure fell from 72 +/- 19 mmHg (CPH) to 54 +/- 17 mmHg (Low-Flow) and 47 +/- 17 mmHg (High-Flow) (P < 0.001). Cardiac output increased from 1.5 +/- 0.3 l/min at CPH to 1.8 +/- 0.4 l/min at Low-Flow (286 +/- 105 ml/min, 15% of cardiac output; P < 0.001), but returned to 1.6 +/- 0.3 l/min at High-Flow (466 +/- 172 ml/min, 29% of cardiac output; P = 0.008 vs. Low-Flow, P = 0.21 vs. CPH). There was a modest rise in systemic oxygen delivery from 252 +/- 46 ml/min at CPH to 276 +/- 50 ml/min at Low-Flow (P = 0.07), but substantial fall to 222 +/- 50 ml/min at High-Flow (P = 0.005 vs. CPH, P < 0.001 vs. Low-Flow). With progressive shunting, bichamber contractility did not change (P = 0.98), but the slope of the right atrial end-diastolic pressure volume relation decreased (P < 0.04), consistent with improved compliance. This study demonstrated that Low-Flow interatrial shunting consistently improved right atrial mechanics and systemic perfusion in subjects with CPH, while High-Flow exceeded an "ideal shunt fraction".

Cavitating lung lesions in chronic thromboembolic pulmonary hypertension

PURPOSE

The aim of this study is to assess the incidence and natural history of cavitating lung lesions in chronic thromboembolic pulmonary hypertension (CTEPH), note thrombus position between patients with and without a cavity and determine whether their development is a predictor of mortality. MATERIALS #ENTITYSTARTX00026;

METHODS

All patients with confirmed CTEPH attending our Pulmonary Vascular Unit between February 1998 and January 2006 were identified, and a review of their notes and imaging was performed. Thrombus position, pre-disposing factors, cavity progression and mortality were noted, and comparisons made between those with and without a cavity.

RESULTS

11 of 104 patients had a cavity (10.6%). Thrombus distribution was similar between those with and those without a cavity. Preceding infection was not proven in most cases. 27.3% of patients with a cavity died compared to 26.8% of those without.

CONCLUSION

Cavity formation in CTEPH is 3 times more common than in acute pulmonary embolism. Thrombus position does not predict cavity development, and the presence of a cavity may serve as an indicator of disease severity but does not appear to predict mortality.

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.

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.