Long-term outcome of lung and heart-lung transplantation for idiopathic pulmonary arterial hypertension

Influence of cardiac diagnosis on outcomes of pediatric heart-lung transplantation

OBJECTIVE

Pediatric Heart-lung transplant (HLTX) is performed for endstage congenital heart disease (CHD) with irreversible pulmonary hypertension or non-congenital heart disease (NCHD) with end-stage heart and lung disease. CHD could influence the outcomes of HTLX due to increased complexity of the operation as compared to NCHD. In this study we evaluated the influence of cardiac diagnosis on outcomes of pediatric HTLX.

METHODS

The UNOS database (1987-2022) was queried for primary HTLX in patients <18 years. The data were extracted for demographics, pretransplant characteristics, post-transplant outcomes, and analyzed for the impact of cardiac diagnosis on post-transplant outcomes. Standard statistical tests were used. Survival was compared using the Kaplan-Meier method.

RESULTS

Ninety of the 213 patients who underwent HLTX had CHD. There were no demographic differences. Heart listing status was similar but with a higher LAS score for NCHD. NCHD had higher pre-operative life support use (mechanical ventilation, inotropes or dialysis) but the use of ECMO as a bridge to transplantation was similar. Wait-list times were longer for CHD. The ischemic times were similar. Post-transplant dialysis, stroke, prolonged mechanical ventilation, and rejection were similar. Survival at 30-days, 1-year, and long-term survival at 17 years was similar. Non-survivors at 30-days post-transplant were on life support, used ECMO as a bridge, had lower wait-list times, longer ischemic times and had strokes. Non-survivors at 1-year had similar factors in addition to a higher dialysis use.

CONCLUSION

Cardiac diagnosis had no impact on outcomes after Pediatric HLTX. Patients on life support or ECMO before transplantation were transplanted faster but with lower survival.

Prognosis factors in heart-lung transplantation: 30 years experience in a reference center

INTRODUCTION

Heart-lung transplantation has shown a progressive decrease in the number of procedures. There is a lack of information about this field in Spain. The main goal of this study is to analyze the experience of a national reference hospital.

METHODS

We performed a retrospective study of a historical cohort of heart-lung transplanted patients in a single center, during a 30 years period (from 1990 to 2021). The associations between variables were evaluated using the χ2 test or Fisher's exact test. Survival was analyzed using the Kaplan-Meier method. Differences were evaluated using the log-rank test and multivariate analysis with the Cox method.

RESULTS

A decrease in the number of procedures performed in the last decade was observed [2000-2009: 19 procedures (44.2%); 2010-2021: 15 procedures (34.8%)]. Early postoperative mortality was 23.3%, falling to 13.3% from 2010. In-hospital mortality was 41%, falling to 33% from 2010. Main factors related to higher mortality: previous thoracic surgery, corticosteroid therapy, extracorporeal circulation (ECLS) greater than 200 min, ischemia time greater than 300 min, and tracheal dehiscence (p < 0.005). Overall survival at one, five, and ten years was 58%, 44.7%, and 36.1%, respectively. Factors associated with lower survival rates: previous thoracic surgery, male donor, extracorporeal circulation greater than 200 min, ischemia time greater than 300 min, tracheal dehiscence and weight difference (p < 0.005).

CONCLUSIONS

There has been a progressive decrease in the number of heart-lung transplantations, being more evident in the last decade, but showing an improvement in both mortality and survival.

Double-lung versus heart-lung transplantation for end-stage cardiopulmonary disease: a systematic review and meta-analysis

We compared posttransplant outcomes following double-lung transplantation (DLTx) and heart-lung transplantation (HLTx), based on a search of PubMed, Cochrane Library, and Embase, from inception to March 8, 2022, for studies that report outcomes of these procedures. We then performed a meta-analysis of baseline characteristics and posttransplant outcomes. Subgroup analyses were implemented according to indication, publication year, and center. This study was registered on PROSPERO (number CRD42020223493). Ten studies were included in this meta-analysis, involving 1230 DLTx patients and 1022 HLTx patients. The DLTx group was characterized by older donors (P = 0.04) and a longer allograft ischemia time (P < 0.001) than the HLTx group. The two groups had comparable 1-year, 3-year, 5-year, 10-year survival rates (all P > 0.05), with similar results identified in subgroup analyses. We found no significant differences in 1-year, 5-year, and 10-year chronic lung allograft dysfunction (CLAD)-free survival, length of intensive care unit stay and hospital stay, length of postoperative ventilation, in-hospital mortality, or surgical complications between the groups (all P > 0.05). Thus, DLTx provides similar posttransplant survival to HLTx for end-stage cardiopulmonary disease. These two procedures have a comparable risk of CLAD and other posttransplant outcomes.

Lung preservation: from perfusion to temperature

PURPOSE OF REVIEW

This article will review the evidence behind elements of the lung preservation process that have remained relatively stable over the past decade as well as summarize recent developments in ex-vivo lung perfusion and new research challenging the standard temperature for static cold storage.

RECENT FINDINGS

Ex-vivo lung perfusion is becoming an increasingly well established means to facilitate greater travel distance and allow for continued reassessment of marginal donor lungs. Preliminary reports of the use of normothermic regional perfusion to allow utilization of lungs after DCD recovery exist, but further research is needed to determine its ability to improve upon the current method of DCD lung recovery. Also, research from the University of Toronto is re-assessing the optimal temperature for static cold storage; pilot studies suggest it is a feasible means to allow for storage of lungs overnight to allow for daytime transplantation, but ongoing research is awaited to determine if outcomes are superior to traditional static cold storage.

SUMMARY

It is crucial to understand the fundamental principles of organ preservation to ensure optimal lung function posttransplant. Recent advances in the past several years have the potential to challenge standards of the past decade and reshape how lung transplantation is performed.

Primary graft dysfunction following lung transplantation: From pathogenesis to future frontiers

Lung transplantation is the treatment of choice for patients with end-stage lung disease. Currently, just under 5000 lung transplants are performed worldwide annually. However, a major scourge leading to 90-d and 1-year mortality remains primary graft dysfunction. It is a spectrum of lung injury ranging from mild to severe depending on the level of hypoxaemia and lung injury post-transplant. This review aims to provide an in-depth analysis of the epidemiology, pathophysiology, risk factors, outcomes, and future frontiers involved in mitigating primary graft dysfunction. The current diagnostic criteria are examined alongside changes from the previous definition. We also highlight the issues surrounding chronic lung allograft dysfunction and identify the novel therapies available for ex-vivo lung perfusion. Although primary graft dysfunction remains a significant contributor to 90-d and 1-year mortality, ongoing research and development abreast with current technological advancements have shed some light on the issue in pursuit of future diagnostic and therapeutic tools.

Surgical management of giant pulmonary artery aneurysms in patients with severe pulmonary arterial hypertension

BACKGROUND AND AIM

Giant aneurysm of the pulmonary artery (PAA) is an extremely rare condition that may develop in patients with pulmonary arterial hypertension (PAH) which may be complicated by rupture, dissection or intravascular thrombus formation. The aim of this study was to examine available literature with regard to surgical strategies in patients undergoing transplantation for PAH with PAA.

RESULTS

These patients were traditionally considered for heart-lung transplantation but more recently, there have been reports of successful lung transplantation with reconstruction of the pulmonary artery.

CONCLUSIONS

Unless there is a mandatory indication for heart-lung transplantation, patients with PAH and PAA can undergo lung transplantation and reconstruction of the pulmonary artery without compromising the outcome.

Update on pediatric pulmonary arterial hypertension

PURPOSE OF REVIEW

Pulmonary arterial hypertension (PAH) causes high morbidity and mortality in children. In this review, we discuss advances in diagnosis and treatment of this disorder.

RECENT FINDINGS

Proceedings published from the 2018 World Symposium updated the definition of pulmonary hypertension to include all adults and children with mean pulmonary artery pressure more than 20 mmHg. Targeted PAH therapy is increasingly used off-label, but in 2017, bosentan became the first Food and Drug Administration-targeted PAH therapy approved for use in children.

SUMMARY

In recent years, advanced imaging and clinical monitoring have allowed improved risk stratification of pulmonary hypertension patients. New therapies, approved in adults and used off-label in pediatric patients, have led to improved outcomes for affected children.

Immunosuppression considerations in simultaneous organ transplant

Solid organ transplantation is a life-saving procedure for patients in the end stage of heart, lung, kidney, and liver failure. For patients with more than one failing organ, simultaneous organ transplantation has emerged as a viable treatment option. Immunosuppression strategies and outcomes for simultaneous organ transplant recipients have been reported, but often involve limited populations. Transplanting dual organs poses challenges in terms of balancing immunosuppression with immunologic risk and allograft damage from surgical complications. Furthermore, transplanting certain organs can impose considerations on the management of immunosuppression. For example, liver allografts may confer immunologic privilege and lower rates of rejection of other allografts. This review article evaluates immunosuppression strategies for simultaneous kidney-pancreas, liver-kidney, heart-kidney, heart-liver, heart-lung, lung-liver, and lung-kidney transplants. To date, no comprehensive review exists to address immunosuppressive strategies in simultaneous organ transplant populations. Our review summarizes the available literature and provides evidence-based recommendations regarding immunosuppression strategies in simultaneous organ transplant recipients.

Pediatric Pulmonary Arterial Hypertension

Pulmonary hypertension (PH), the syndrome of increased pressure in the pulmonary arteries, is associated with significant morbidity and mortality for affected children and is associated with a variety of potential underlying causes. Several pulmonary arterial hypertension-targeted therapies have become available to reduce pulmonary artery pressure and improve outcome, but there is still no cure for most patients. This review provides a description of select causes of PH encountered in pediatrics and an update on the most recent data pertaining to evaluation and management of children with PH. Available evidence for specific classes of PH-targeted therapies in pediatrics is discussed.

Review 2: Primary graft dysfunction after lung transplant-pathophysiology, clinical considerations and therapeutic targets

Primary graft dysfunction (PGD) is one of the most common complications in the early postoperative period and is the most common cause of death in the first postoperative month. The underlying pathophysiology is thought to be the ischaemia–reperfusion injury that occurs during the storage and reperfusion of the lung engraftment; this triggers a cascade of pathological changes, which result in pulmonary vascular dysfunction and loss of the normal alveolar architecture. There are a number of surgical and anaesthetic factors which may be related to the development of PGD. To date, although treatment options for PGD are limited, there are several promising experimental therapeutic targets. In this review, we will discuss the pathophysiology, clinical management and potential therapeutic targets of PGD.

Use of pulmonoplegia and delivery system during recipient surgery in lung transplantation

Lung transplantation in the United States has steadily grown over the last decade. Major attention has been with the understanding of lung ischemia-reperfusion injury and how it relates to primary graft dysfunction. In 2015, our institution implemented the use of a pulmonoplegia solution during recipient surgery of lung transplantation. A unique circuit utilizing the heart lung machine is used to deliver the pulmonoplegia solution. This system is considered to be a key contributing factor to the success of our lung transplant program.

Pulmonary arterial hypertension: the case for a bioelectronic treatment

Pulmonary arterial hypertension (PAH) is a rare disease of unknown etiology that progresses to right ventricular failure. It has a complex pathophysiology, which involves an imbalance between vasoconstrictive and vasodilative processes in the pulmonary circulation, pulmonary vasoconstriction, vascular and right ventricular remodeling, systemic inflammation, and autonomic imbalance, with a reduced parasympathetic and increased sympathetic tone. Current pharmacological treatments for PAH include several classes of drugs that target signaling pathways in vascular biology and cardiovascular physiology, but they can have severe unwanted effects and they do not typically stop the progression of the disease. Pulmonary artery denervation has been tested clinically as a method to suppress sympathetic overactivation, however it is a nonspecific and irreversible intervention. Bioelectronic medicine, in particular vagus nerve stimulation (VNS), has been used in cardiovascular disorders like arrhythmias, heart failure and arterial hypertension and could, in principle, be tested as a treatment in PAH. VNS can produce pulmonary vasodilation and renormalize right ventricular function, via activation of pulmonary and cardiac vagal fibers. It can suppress systemic inflammation, via activation of fibers that innervate the spleen. Finally, VNS can gradually restore the balance between parasympathetic and sympathetic tone by regulating autonomic reflexes. Preclinical studies support the feasibility of using VNS in PAH. However, there are challenges with such an approach, arising from the need to affect a relatively small number of relevant vagal fibers, and the potential for unwanted cardiac and noncardiac effects of VNS in this sensitive patient population.

Double-lung versus heart-lung transplantation for precapillary pulmonary arterial hypertension: a 24-year single-center retrospective study

Transplant type for end-stage pulmonary vascular disease remains debatable. We compared recipient outcome after heart-lung (HLT) versus double-lung (DLT) transplantation. Single-center analysis (38 HLT-30 DLT; 1991-2014) for different causes of precapillary pulmonary hypertension (PH): idiopathic (22); heritable (two); drug-induced (nine); hepato-portal (one); connective tissue disease (four); congenital heart disease (CHD) (24); chronic thromboembolic PH (six). HLT decreased from 91.7% [1991-1995] to 21.4% [2010-2014]. Re-intervention for bleeding was higher after HLT; (P = 0.06) while primary graft dysfunction grades 2 and 3 occurred more after DLT; (P < 0.0001). Graft survival at 90 days, 1, 5, 10, and 15 years was 93%, 83%, 70%, 47%, and 35% for DLT vs. 82%, 74%, 61%, 48%, and 30% for HLT, respectively (log-rank P = 0.89). Graft survival improved over time: 100%, 93%, 87%, 72%, and 72% in [2010-2014] vs. 75%, 58%, 42%, 33%, and 33% in [1991-1995], respectively; P = 0.03. No difference in chronic lung allograft dysfunction (CLAD)-free survival was observed: 80% & 28% for DLT vs. 75% & 28% for HLT after 5 and 10 years, respectively; P = 0.49. Primary graft dysfunction in PH patients was lower after HLT compared to DLT. Nonetheless, overall graft and CLAD-free survival were comparable and improved over time with growing experience. DLT remains our preferred procedure for all forms of precapillary PH, except in patients with complex CHD.

Pulmonary Hypertension: The Role of Lung Transplantation

Despite advances in targeted medical therapy, pulmonary arterial hypertension (PAH) remains a fatal disease because of progressive right ventricular dysfunction. For patients who are refractory to medical therapy, heart-lung and lung transplantation are important treatment options. Because of longer waiting time, surgical interventions including extracorporeal lung support and atrial septostomy can be used in PAH patients bridging to transplantation.

Lung transplantation for idiopathic pulmonary arterial hypertension on intraoperative and postoperatively prolonged extracorporeal membrane oxygenation provides optimally controlled reperfusion and excellent outcome

OBJECTIVES

Lung transplantation for idiopathic pulmonary arterial hypertension has the highest reported postoperative mortality of all indications. Reasons lie in the complexity of treatment of these patients and the frequent occurrence of postoperative left ventricular failure. Transplantation on intraoperative extracorporeal membrane oxygenation support instead of cardiopulmonary bypass and even more the prolongation of extracorporeal membrane oxygenation into the postoperative period helps to overcome these problems. We reviewed our experience with this concept.

METHODS

All patients undergoing bilateral lung transplantation for idiopathic pulmonary arterial hypertension on intraoperative extracorporeal membrane oxygenation with or without prophylactic extracorporeal membrane oxygenation prolongation into the postoperative period between January 2000 and December 2014 were retrospectively analysed.

RESULTS

Forty-one patients entered the study. Venoarterial extracorporeal membrane oxygenation support was prolonged into the postoperative period for a median of 2.5 days (range 1–40). Ninety-day, 1-, 3- and 5-year survival rates for the patient collective were 92.7%, 90.2%, 87.4% and 87.4%, respectively. When compared with 31 patients with idiopathic pulmonary arterial hypertension transplanted in the same period of time without prolongation of extracorporeal membrane oxygenation into the postoperative period, the results compared favourably (83.9%, 77.4%, 77.4%, and 77.4%; P = 0.189). Furthermore, these results are among the best results ever reported for this particularly difficult patient population.

CONCLUSIONS

Bilateral lung transplantation for idiopathic pulmonary arterial hypertension with intraoperative venoarterial extracorporeal membrane oxygenation support seems to provide superior outcome compared with the results reported about the use of cardiopulmonary bypass. Prophylactic prolongation of venoarterial extracorporeal membrane oxygenation into the early postoperative period provides stable postoperative conditions and seems to further improve the results.

Diagnosis, Evaluation and Treatment of Pulmonary Arterial Hypertension in Children

Pulmonary Hypertension (PH), the syndrome of elevated pressure in the pulmonary arteries, is associated with significant morbidity and mortality for affected children. PH is associated with a wide variety of potential underlying causes, including cardiac, pulmonary, hematologic and rheumatologic abnormalities. Regardless of the cause, for many patients the natural history of PH involves progressive elevation in pulmonary arterial resistance and pressure, right ventricular dysfunction, and eventually heart failure. In recent years, a number of pulmonary arterial hypertension (PAH)-targeted therapies have become available to reduce pulmonary artery pressure and improve outcome. A growing body of evidence in both the adult and pediatric literature demonstrates enhanced quality of life, functional status, and survival among treated patients. This review provides a description of select etiologies of PH seen in pediatrics and an update on the most recent data pertaining to evaluation and management of children with PH/PAH. The available evidence for specific classes of PAH-targeted therapies in pediatrics is additionally discussed.

High Frequency of Acute Adverse Cardiovascular Events After Lung Transplantation in Patients With Pulmonary Arterial Hypertension Receiving Preoperative Long-Term Intravenous Prostacyclin

Adverse cardiovascular events after lung transplantation (LT) increase the mortality in patients with pulmonary arterial hypertension (PAH). Long-term intravenous prostacyclin is the usual treatment in severe patients with PAH, but it may increase the risk of hemorrhage due to its antiplatelet aggregation effect or thrombocytopenia. We investigated the impact of length of intravenous prostacyclin therapy on acute adverse cardiovascular events including hemorrhagic complication after LT. We retrospectively compared the incidence of adverse events (death, intrathoracic hematoma and bleeding, cardiac congestion or shock, cerebral infarction and pulmonary embolism) within 30 days after LT between no/short-term (median 0.6 years, n = 13) and long-term (median 3.7 years, n = 15) intravenous prostacyclin groups. There were no differences in the dose of intravenous prostacyclin and pulmonary artery pressure between the two groups. Among 22 adverse events (0.8 ± 1.1 events/patient), 4 events occurred in the no/short-term intravenous prostacyclin group and 18 occurred in the long-term intravenous prostacyclin group. The event rate per patient in the long-term intravenous prostacyclin group (1.2 ± 1.3 events/patient) was significantly higher than that in the no/short-term intravenous prostacyclin group (0.3 ± 0.5 events/patient) (P < 0.05). Intrathoracic hematoma and bleeding was the most frequent adverse event (9 events, 41%). Preoperative long-term intravenous prostacyclin therapy increases acute adverse cardiovascular events after LT in patients with PAH.

State of the Art of Combined Heart-Lung Transplantation for Advanced Cardiac and Pulmonary Dysfunction

Over the last several decades, significant advances and improvements in care of transplant patients have resulted in markedly improved outcomes. A number of options are available for patients with advanced cardiopulmonary dysfunction requiring transplantation. There is a debate about when isolated heart or isolated lung transplantation is no longer possible or advisable and combined heart-lung transplantation is justified. Organ availability and allocation severely limit the latter option to very few well-selected patients. We review practice patterns, trends, and outcomes after triple-organ heart-lung transplant (HLTx) worldwide, as well as our own experience with heart-lung transplant in the modern era.

[Pulmonary hypertension: definition, classification and treatments]

Pulmonary hypertension (PH) is a cardio-pulmonary disorder that may involve multiple clinical conditions and can complicate the majority of cardiovascular and respiratory diseases. Its definition is an increase in mean pulmonary artery pressure (mPAP) \hbox{$\geqslant $} ⩾ 25 mmHg at rest, leading to right heart failure and ultimately death. The clinical classification of pulmonary hypertension (PH) categorizes PH into groups which share similar pathophysiological and hemodynamic characteristics and treatments. Five groups of disorders that cause PH are identified: pulmonary arterial hypertension (Group 1) which is a pre-capillary PH, defined by a normal pulmonary artery wedge pressure (PAWP) \hbox{$\leqslant $} ⩽ 15 mmH, due to remodelling of the small pulmonary arteries (<500 μm); pulmonary hypertension due to left heart disease (Group 2) which is a post-capillary PH, defined by an increased pulmonary artery wedge pressure (PAWP) >15 mmHg; pulmonary hypertension due to chronic lung disease and/or hypoxia (Group 3); chronic thrombo-embolic pulmonary hypertension (Group 4); and pulmonary hypertension due to unclear and/or multifactorial mechanisms (Group 5). PAH (PH group 1) can be treated with agents targeting three dysfunctional endothelial pathways of PAH: nitric oxide (NO) pathway, endothelin-1 pathway and prostacyclin pathway. Patients at low or intermediate risk can be treated with either initial monotherapy or initial oral combination therapy. In patients at high risk initial combination therapy including intravenous prostacyclin analogues should be considered. Patients with inadequate clinical response to maximum treatment (triple therapy with an intravenous prostacyclin) should be assessed for lung transplantation. Despite progresses, PAH remains a fatal disease with a 3-year survival rate of 58%. Treatment of group 2, group 3 and group 5 PH is the treatment of the causal disease and PAH therapeutics are not recommended. Treatment of group 4 PH is pulmonary endarteriectomy if patients are eligible, otherwise balloon pulmonary angioplasty and/or medical therapy can be considered.

Pulmonary Hypertension in Children

The prevalence of PH is increasing in the pediatric population, because of improved recognition and increased survival of patients, and remains a significant cause of morbidity and mortality. Recent studies have improved the understanding of pediatric PH, but management remains challenging because of a lack of evidence-based clinical trials. The growing contribution of developmental lung disease requires dedicated research to explore the use of existing therapies as well as the creation of novel therapies. Adequate study of pediatric PH will require multicenter collaboration due to the small numbers of patients, multifactorial disease causes, and practice variability.

A global perspective of lung transplantation: Part 1 - Recipient selection and choice of procedure

Lung transplantation has grown considerably in recent years and its availability has spread to an expanding number of countries worldwide. Importantly, survival has also steadily improved, making this an increasingly viable procedure for patients with end-stage lung disease and limited life expectancy. In this first of a series of articles, recipient selection and type of transplant operation are reviewed. Pulmonary fibrotic disorders are now the most indication in the U.S., followed by chronic obstructive pulmonary disease and cystic fibrosis. Transplant centers have liberalized criteria to include older and more critically ill candidates. A careful, systematic, multi-disciplinary selection process is critical in identifying potential barriers that may increase risk and optimize long-term outcomes.

2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension

Guidelines summarize and evaluate all available evidence on a particular issue at the time of the writing process, with the aim of assisting health professionals in selecting the best management strategies for an individual patient with a given condition, taking into account the impact on outcome, as well as the risk–benefit ratio of particular diagnostic or therapeutic means. Guidelines and recommendations should help health professionals to make decisions in their daily practice. However, the final decisions concerning an individual patient must be made by the responsible health professional(s) in consultation with the patient and caregiver as appropriate.

Severe pulmonary arterial hypertension: treatment options and the bridge to transplantation

Pulmonary arterial hypertension (PAH) is a rare disease leading to right heart failure and death. Prognosis remains poor, particularly for patients with severe disease, i.e. World Health Organization functional class IV. There have been significant improvements in treatment options. Several agents are available that target the three main established PAH disease pathways, and can be combined sequentially or upfront. Strong scientific evidence supports the use of intravenous epoprostenol in severe PAH; however, despite recommendations, many patients do not receive parenteral prostanoids and there is a lack of evidence from randomised clinical trials supporting the value of other PAH medications alone in severe PAH. Lung transplantation is an important option in patients with severe PAH who have not responded sufficiently to therapy, or who have worsened despite maximal treatment. Bridging techniques are available for patients who worsen while awaiting transplantation. The type of bridging technique used depends on various factors including patient illness severity, physician experience and the anticipated waiting time for transplantation. With the aim to facilitate the treatment decision-making process, herein we review the medical treatment options available for patients with severe PAH, and the bridging techniques that may be used to sustain patients awaiting transplantation.

Heart-lung transplantation: adult indications and outcomes

Combined heart-lung transplantation remains the only definitive therapy for patients who have both end-stage heart failure and end-stage lung failure. The most common indication is congenital heart disease (CHD) and the proportion is increasing for acquired heart disease concomitant with pulmonary hypertension and/or intrinsic lung diseases. Previously, idiopathic pulmonary hypertension was the most common indication. However, it has been shown that right ventricular failure can be reversed after double lung transplantation. Therefore, patients with idiopathic pulmonary arterial hypertension (IPAH) should not undergo combined heart-lung transplantation unless left ventricular dysfunction co-exists. The ISHLT registry data shows survival after heart-lung transplantation is improving, but still its survival rates are 71% at 3 months, 63% at 1 year, 44% at 5 years and 31% at 10 years. With appropriate patient selection and surgical expertise, these outcomes should improve further.

Updated treatment algorithm of pulmonary arterial hypertension

The demands on a pulmonary arterial hypertension (PAH) treatment algorithm are multiple and in some ways conflicting. The treatment algorithm usually includes different types of recommendations with varying degrees of scientific evidence. In addition, the algorithm is required to be comprehensive but not too complex, informative yet simple and straightforward. The type of information in the treatment algorithm are heterogeneous including clinical, hemodynamic, medical, interventional, pharmacological and regulatory recommendations. Stakeholders (or users) including physicians from various specialties and with variable expertise in PAH, nurses, patients and patients' associations, healthcare providers, regulatory agencies and industry are often interested in the PAH treatment algorithm for different reasons. These are the considerable challenges faced when proposing appropriate updates to the current evidence-based treatment algorithm.The current treatment algorithm may be divided into 3 main areas: 1) general measures, supportive therapy, referral strategy, acute vasoreactivity testing and chronic treatment with calcium channel blockers; 2) initial therapy with approved PAH drugs; and 3) clinical response to the initial therapy, combination therapy, balloon atrial septostomy, and lung transplantation. All three sections will be revisited highlighting information newly available in the past 5 years and proposing updates where appropriate. The European Society of Cardiology grades of recommendation and levels of evidence will be adopted to rank the proposed treatments.

Should we perform bilateral-lung or heart–lung transplantation for patients with pulmonary hypertension?

A best evidence topic was constructed according to a structured protocol. The following question was addressed: of the following two procedures, heart–lung transplantation or bilateral-lung transplantation (BLTx), which offers the best outcome for patients with pulmonary hypertension (PH) listed for thoracic transplantation? Of the 77 papers found using a report search for PH and thoracic transplantation, 9 represented the best evidence to answer this clinical question. Overall, 1189 (67%) lung transplantations and 578 (33%) heart–lung transplantations have been reported worldwide for idiopathic PH. For patients with Eisenmenger's syndrome, HLTx represents up to 70% of the transplantation procedures they undergo. On the whole, neither procedure demonstrated an overall survival benefit, when compared with the other. However, PH patients represent a heterogeneous population according to (i) the primary mechanism of PH and (ii) the consequences of PH on right or/and left heart function. With regard to the latter consideration, the current evidence shows that HLTx offers excellent functional and survival outcomes for patients with congenital heart disease and Eisenmenger's syndrome, severe right or/and left heart dysfunction, and who are chronically inotropic dependent. As far as heart dysfunction is concerned, the published evidence approximated cut-off values at 10–25% for the right ventricle ejection fraction (RVEF) and at 32–55% for the left ventricle ejection fraction (LVEF). In the case of lower values for RVEF and LVEF, HLTx should be performed. In all other patients with PH, the evidence demonstrated that BLTx offers a comparable outcome with the advantage of better organ sharing for other recipients. In order to reduce the waiting time on transplantation lists, cardiac repair and BLTx can be offered in experienced centres to patients with simple cardiac anomalies such as atrial septal defect, patent ductus arteriosus or perimembranous ventricular septal defect.

Transplantation for Idiopathic Pulmonary Arterial Hypertension

Background—

Lung transplantation and heart-lung transplantation represent surgical options for treatment of medically refractory idiopathic pulmonary arterial hypertension. The effect of the lung allocation score on wait-list and transplantation outcomes in patients with idiopathic pulmonary arterial hypertension is poorly described.

Methods and Results—

Adults diagnosed with idiopathic pulmonary arterial hypertension and listed for transplantation in the 80 months before and after the lung allocation score algorithm was implemented (n=1430) were identified in the United Network for Organ Sharing thoracic registry. Patients were stratified by organ listed and pre– and post–lung allocation score era. The cumulative incidences of transplantation and mortality for wait-listed patients in both eras were appraised with competing outcomes analysis. Posttransplantation survival was assessed with the Kaplan-Meier method. These analyses were repeated in propensity-matched subgroups. Cox proportional hazards analysis evaluated the effect of prelisting and pretransplantation characteristics on mortality. We found that patients in the post–lung allocation score era had significantly worse comorbidities; nevertheless, both lung transplantation and heart-lung transplantation candidates in this era enjoyed lower wait-list mortality and a higher incidence of transplantation in unmatched and propensity-matched analyses. On multivariable analysis, heart-lung transplantation and double-lung transplantation were associated with improved survival from the time of wait-listing, as was being listed at a medium- to high-volume institution. Donor/recipient sex matching predicted posttransplantation survival.

Conclusions—

The incidence of transplantation has increased while wait-list mortality has decreased in patients with idiopathic pulmonary arterial hypertension wait-listed for transplantation in the post–lung allocation score era. Both heart-lung transplantation and double-lung transplantation are predictive of survival in transplantation candidates with idiopathic pulmonary arterial hypertension, as is being listed at a medium- to high-volume institution. Donor/recipient sex matching is associated with better posttransplantation survival.

Efficacy of extracorporeal membrane oxygenation as a bridge to lung transplantation

BACKGROUND

Preoperative extracorporeal membrane oxygenation (ECMO) is a risk factor for poor outcome and currently considered a contraindication to lung transplantation. The lung allocation score system was introduced in May 2005 and prioritizes lung allocation to those with the greatest respiratory impairment. The purpose of this study is to determine whether ECMO as a bridge to lung transplantation is an acceptable option to support those in respiratory failure until donor lungs become available in the lung allocation score era.

METHOD

A retrospective review of 715 consecutive lung transplants performed between May 2005 and September 2011 was conducted using a prospectively collected institutional registry database. Twenty-four lung transplants (3.4%) were performed in the 31 patients with attempted pretransplant ECMO; 7 patients who received ECMO patients did not survive or were deemed unfit for transplantation. These patients were compared with a control group of 691 patients who did not receive pretransplant ECMO.

RESULTS

The duration of pretransplant ECMO was 171 ± 242 hours (median, 91 hours). Venovenous ECMO was used for respiratory failure in 15 patients, whereas venoarterial ECMO was used for circulatory collapse due to pulmonary hypertension in 9 patients. Patients in the retransplant ECMO group were younger (46 ± 15 years vs 57 ± 14 years, P < .01) compared with the control group, with no difference in recipient gender (male/female: 10/14 vs 380/311), donor age (33 ± 14 years vs 36 ± 15 years), or donor gender (male/female: 10/14 vs 352/339). Emphysema was less common (1, 4% vs 260, 38%, P < .01), and cystic fibrosis (5, 21% vs 72, 10%, P = .09), redo lung transplant (3, 13% vs 28, 4%, P = .08), and bronchiectasis (2, 8% vs 6, 1%, P = .03) were more common in the pretransplant ECMO group. Patients in the pretransplant ECMO group had a significantly higher lung allocation score (87 ± 9 vs 44 ± 15, P < .01). All patients in the pretransplant ECMO group underwent double lung transplants on pump (cardiopulmonary bypass/ECMO), and single lung transplants were performed in 171 patients (25%) and pump was used in 243 patients (35%) in the control group. The cardiopulmonary bypass time was longer in the pretransplant ECMO group (277 ± 69 minutes vs 225 ± 89 minutes, P = .02), with no difference in ischemic time (343 ± 93 minutes vs 330 ± 98 minutes, P = .54). Cadaveric lobar lung transplants were performed because of the urgency to overcome size mismatch with an oversized donor more frequently in 25% (n = 6, no mortality with the longest follow-up at 6 years) of patients in the pretransplant ECMO group versus 0.3% (n = 2) of patients in the control group (P < .01). Post-transplant ECMO was used for primary graft dysfunction in 13 patients (54%) in the pretransplant ECMO group and 41 patients (6%) in the control group (P < .01). The median hospital stay was 46 days in the pretransplant ECMO group versus 27 days in the control group (P = .16). The actuarial survivals after lung transplants at 1, 3, 6, 12, and 24 months were 96%, 88%, 83%, 74%, and 74%, respectively, in the pretransplant ECMO group, and 97%, 94%, 90%, 83%, and 74%, respectively, in the control group (P = .787).

CONCLUSIONS

Although the incidence of primary graft dysfunction requiring post-transplant ECMO is higher and the hospital stay is longer in patients receiving pretransplant ECMO, the graft survival is good (2-year survival, 74%). ECMO is efficacious as a bridge to lung transplantation with good post-lung transplant outcomes.

Lung transplantation in patients with prior cardiothoracic surgical procedures

The full spectrum of prior cardiothoracic procedures in lung transplant candidates and the impact of prior procedures on outcomes after lung transplantation (LTx) remain unknown, though the impact is considered to be large. Patients transplanted at our institution from 2004 to 2009 were identified (n = 554) and divided into two groups: patients who had undergone cardiothoracic surgical (CTS) procedures prior to LTx (n = 238) and patients who had not (non-CTS: n = 316). Our primary endpoint was survival. Secondary endpoints included allograft function and the incidence of major complications including reexploration due to bleeding, prolonged ventilation, renal insufficiency and primary graft dysfunction. Long-term survival was not significantly different between the groups whereas postoperative bleeding, nerve injury, respiratory and renal complications were higher in the CTS group. Posttransplant peak FEV1 was lower in the CTS group (73.4% vs. 86.9%, p < 0.05). In multivariate analysis, performance of a chemical pleurodesis procedure and prolonged cardiopulmonary bypass were significantly associated with mortality (OR, 1.7; CI, 1.5-2.0; p < 0.005). Our results suggest that patients with LTx and prior CTS remain technically challenging and experience worse outcomes than patients without prior CTS. A surgical strategy to minimize cardiopulmonary bypass time is critical for these challenging LTx patients.

Effect of chronic sodium nitrite therapy on monocrotaline-induced pulmonary hypertension

Pulmonary hypertension (PH) is a rare disorder that without treatment is progressive and often fatal within 3 years. The treatment of PH involves the use of a diverse group of drugs and lung transplantation. Although nitrite was once thought to be an inactive metabolite of endothelial-derived nitric oxide (NO), there is increasing evidence that nitrite may be useful in the treatment of PH, but the mechanism by which nitrite exerts its beneficial effect remains uncertain. The purpose of this study was to investigate the effect of chronic sodium nitrite treatment in a PH model in the rat. Following induction of PH with a single injection of monocrotaline, 60 mg; daily ip injections of sodium nitrite (3mg/kg) starting on day 14 and continuing for 21 days, resulted in a significantly lower pulmonary arterial pressure on day 35 when compared to values in untreated animals with monocrotaline-induced PH. In monocrotaline-treated rats, daily treatment with ip nitrite injections for 21 days decreased right ventricular mass and pathologic changes in small pulmonary arteries. Nitrite therapy did not change systemic arterial pressure or cardiac output when values were measured on day 35. The decreases in pulmonary arterial pressure in response to iv injections of sodium nitroprusside, sodium nitrite, and BAY 41-8543 were not different in rats with monocrotaline-induced pulmonary hypertension and rats with chronic nitrite therapy when compared to responses in animals in which pulmonary arterial pressure was increased with U46619. These findings are consistent with the hypothesis that the mechanisms that convert nitrite to vasoactive NO, activate soluble guanylyl cyclase and mediate the vasodilator response to NO or an NO derivative are not impaired. The present data are consistent with the results of a previous study in monocrotaline-induced PH in which systemic arterial pressure and cardiac output were not evaluated and are consistent with the hypothesis that nitrite is effective in the treatment of monocrotaline-induced PH in the rodent.

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.

Overview of current therapeutic approaches for pulmonary hypertension

There have been tremendous strides in the management of pulmonary hypertension over the past 20 years with the introduction of targeted medical therapies and overall improvements in surgical treatment options and general supportive care. Furthermore, recent data shows that the survival of those with pulmonary arterial hypertension is improving. While there has been tremendous progress, much work remains to be done in improving the care of those with secondary forms of pulmonary hypertension, who constitute the majority of patients with this disorder, and in the optimal treatment approach in those with pulmonary arterial hypertension. This article will review general and targeted medical treatment, along with surgical interventions, of those with pulmonary hypertension.

Lung transplantation for pulmonary hypertension

Although medical therapies for pulmonary arterial hypertension have greatly improved, it remains a chronic and fatal disease. For patients who are refractory to medical therapy, lung transplantation is an important treatment option. This review discusses issues pertaining to indications for transplant, preparation for transplant and listing, operative issues, and outcomes for patients with pulmonary arterial hypertension.

Pulmonary arterial hypertension and lung transplantation

Transplantation remains the only therapeutic option for selected patients with advanced pulmonary arterial hypertension (PAH) who continue to deteriorate despite optimal pulmonary vasodilator therapy - including intravenous prostanoids and combination therapy. Identification of poor prognostic markers in PAH, including persistence in the New York Heart Association functional class III and IV, and adverse pulmonary hemodynamics at right heart catheterization should prompt early referral for transplantation. There is a need for inclusion of more discriminatory markers of PAH prognosis in donor-lung allocation scores to identify patients at risk and optimize survival to transplantation, given the current shortage of donor organ availability worldwide. Double-lung transplantation is the recommended operation for idiopathic PAH. Heart-lung transplantation is reserved for selected patients with idiopathic PAH with severe right ventricular dysfunction, or congenital heart disease with complex or ventricular septal defect-associated PAH. Novel surgical strategies, including atrial septostomy or the pumpless Novalung® lung assist device with conduits, from the pulmonary artery to the left atrium, can be considered as a bridge to transplant for patients with rapid clinical decline, despite maximal medical therapy. Recent transplant outcomes for PAH are encouraging, albeit with early postoperative risks, a requirement for long-term surveillance, immunosuppression and transplant immunosuppression-specific morbidity.

Combining tricuspid valve repair with double lung transplantation in patients with severe pulmonary hypertension, tricuspid regurgitation, and right ventricular dysfunction

BACKGROUND

Concomitant tricuspid valve repair (TVR) and double lung transplantation (DLTx) has been a surgical option at our institution since 2004 in an attempt to improve the outcome of DLTx for end-stage pulmonary hypertension, severe tricuspid regurgitation, and right ventricle (RV) dysfunction. This study is a review of that single institutional experience.

METHODS

Consecutive cases of concomitant TVR and DLTx performed between 2004 and 2009 (TVR group, n = 20) were retrospectively compared with cases of DLTx alone for severe pulmonary hypertension without TVR (non-TVR group, n = 58).

RESULTS

There was one in-hospital death in the TVR group. The 90-day and 1- and 3-year survival rates for the TVR group were 90%, 75%, and 65%, respectively, which were not significantly different from those for the non-TVR group. The TVR group required less inotropic support and less prolonged mechanical ventilation in the ICU. Follow-up echocardiography demonstrated immediate elimination of both volume and pressure overload in the RV and tricuspid regurgitation in the TVR group. Notably, there was a significantly lower incidence of primary graft dysfunction following transplantation in the TVR group (P < .05). Pulmonary functional improvement shown by an FEV(1) increase after 6 months was also significantly better in the TVR group (40% vs 20%, P < .05).

CONCLUSIONS

Combined TVR and DLTx procedures were successfully performed without an increase in morbidity or mortality and contributed to decreased primary graft dysfunction. In our experience, this combined operative approach achieves clinical outcomes equal or superior to the outcomes seen in DLTx patients without RV dysfunction and severe tricuspid regurgitation.

New approaches to the treatment of pulmonary hypertension: from bench to bedside

Pulmonary hypertension (PH) is a severe, life-threatening disease for which there are no effective curative therapies. A diverse group of agents such as prostacyclins, endothelin antagonists, phosphodiesterase inhibitors, calcium channel blockers, diuretics, inotropic agents, and anticoagulants are used to treat PH; however, none of these agents have a marked effect upon survival. Among the new agents that promise treatment of PH are rho-kinase inhibitors and soluble guanylate cyclase stimulators. Although these new classes of agents have beneficial effects in experimental animal models and clinical studies, they are not selective in their actions on the pulmonary vascular bed. This manuscript reviews the actions of rho-kinase inhibitors and soluble guanylate cyclase stimulators on the pulmonary vascular bed. It is our hypothesis that these new agents may be more effective than current therapies in the treatment of PH. Moreover, new methods in the delivery of these agents to the lung need to be developed so that their main effects will be exerted in the pulmonary vascular bed and their systemic effects can be minimized or avoided.

[Surgical treatment of pulmonary arterial hypertension]

INTRODUCTION

Pulmonary arterial hypertension (PAH) is a severe disease that has undergone a dramatic improvement in therapeutic management over the past 20 years. Among the new therapeutic options, surgery has the potential to dramatically improve or, in some cases, cure PAH.

BACKGROUND

Surgical treatment of PAH includes pulmonary endarterectomy which can cure PAH when the cause is obstruction of the pulmonary arteries by fibrous tissue resulting from pulmonary embolism, by tumours as angiosarcomas, and echinococcus cysts. Transplantation is required in end-stage PAH after failure of medical treatment. Atrial septostomy and Potts procedure are palliative surgical procedures that can delay transplantation.

VIEWPOINT

Extracorporeal cardiopulmonary support is the latest surgical improvement, not only as a bridge to transplantation in end-stage PAH but also during recovery after transplantation or pulmonary endarterectomy.

CONCLUSIONS

Surgery is part of the therapeutic management of PAH. Dialogue between physicians and surgeons is a prerequisite for any reasoned therapeutic decision.