Heart-lung transplantation for primary pulmonary hypertension

Transplant Operative Considerations in Pulmonary Hypertension With Severe Right Heart Failure

Over the past several decades, the operation of choice for end-stage lung disease secondary to severe pulmonary hypertension (PH) has shifted from heart-lung transplantation (HLT) to bilateral lung transplantation (BLT). This change has maintained excellent long-term outcomes and is appropriate for the majority of patients presenting with end-stage disease in need of transplantation. However, a distinct subset of patients with severe PH have an excessive early mortality within 90 days of transplantation. Based on the different causes of this early mortality compared to BLT recipients with other indications, right heart failure and refractory primary graft dysfunction appear to play a significant role. It is therefore critical to identify this subset of patient during their evaluation for transplant. This distinction would allow specific patient referral for HLT, which may mitigate those causes of early mortality. Similarly, there is a subgroup of BLT recipients for severe PH that fail to recover right ventricular function, with suboptimal long-term functional status that is independent of early survival. Identification and referral for HLT of these patients may also be important. In this manuscript, we describe our institutional approach and consideration for the risks of early mortality from right heart failure and primary graft dysfunction, as well failure of right ventricular recovery long term. The described evaluation is used to ascertain those patients with severe PH who may benefit from an HLT over BLT.

Mid-term results of bilateral lung transplant with postoperatively extended intraoperative extracorporeal membrane oxygenation for severe pulmonary hypertension

OBJECTIVES

In severe pulmonary hypertension, diastolic dysfunction of the left ventricle causes significant morbidity and mortality after lung transplantation, which may be successfully reversed using a protocol based on perioperative veno-arterial extracorporeal membrane oxygenation (ECMO) and early extubation. Here, we present echocardiographic data and mid-term outcomes.

METHODS

The records of lung transplanted patients at our institution between May 2010 and January 2016 were retrospectively reviewed. Echocardiography data were collected preoperatively, at discharge, 3 and 12 months after transplantation.

RESULTS

During the study period, 717 patients underwent lung transplantation at our institution, 38 (5%) patients being transplanted for severe pulmonary hypertension. All patients underwent bilateral lung transplantation on veno-arterial ECMO cannulated in the groin, through a sternum sparing thoracotomy in 36 (95%) patients. Extubation was performed early, after a median of 2 days, and awake ECMO was extended for at least 5 days after transplantation. The survival at 3 months, 1 year and 5 years was not different in comparison to patients transplanted for other underlying diseases ( P  = 0.45). At 1 year, tricuspid valve regurgitation had disappeared in all patients. The median of the left ventricular end-diastolic dimension improved from 40 (32-44) mm preoperatively to 45 (44-47) mm at 12 months after lung transplantation ( P  < 0.05). The median of the proximal right ventricular outflow diameter decreased to 25 (23-27) mm after 12 months, compared to 48 (43-51) mm preoperatively ( P  < 0.05).

CONCLUSIONS

The routine application of a prophylactic postoperative veno-arterial ECMO protocol in patients with severe pulmonary hypertension undergoing lung transplantation decreases postoperative mortality and favours achievement of normal cardiac function after 1 year.

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.

Lung transplantation for severe pulmonary hypertension--awake extracorporeal membrane oxygenation for postoperative left ventricular remodelling

BACKGROUND

Bilateral lung transplantation (BLTx) is an established treatment for end-stage pulmonary hypertension (PH). Ventilator weaning failure and death are more common as in BLTx for other indications. We hypothesized that left ventricular (LV) dysfunction is the main cause of early postoperative morbidity or mortality and investigated a weaning strategy using awake venoarterial extracorporeal membrane oxygenation (ECMO).

METHODS

In 23 BLTx for severe PH, ECMO used during BLTx was continued for a minimum of 5 days (BLTx-ECMO group). Echocardiography, left atrial (LA) and Swan-Ganz catheters were used for monitoring. Early extubation after transplantation was attempted under continued ECMO.

RESULTS

Preoperatively, all patients had severely reduced cardiac index (mean, 2.1 L/min/m2). On postoperative day 2, reduction of ECMO flow resulted in increasing LA and decreasing systemic blood pressures. On the day of ECMO explantation (median, postoperative day 8), LV diameter had increased; LA and blood pressures remained stable. Survival rates at 3 and 12 months were 100% and 96%, respectively. Data were compared to two historic control groups of BLTx without ECMO (BLTx ventilation) or combined heart-lung transplantation for severe PH.

CONCLUSION

Early after BLTx for severe PH, the LV may be unable to handle normalized LV preload. This can be effectively bridged with awake venoarterial ECMO.

Physiology of sleep and breathing before and after lung transplantation

During the past 20 years, lung transplantation (LTX) has evolved and it is now accepted as a mainstream modality for care of patients with severe life-threatening respiratory diseases that are refractory to maximal conventional therapies. Improvements in surgical techniques and in antirejection medications have resulted in prolonged survival in these patients. Several studies have explored quality of life after LTX and its improvement has been noted especially in the early period between 3 and 6 months. This article discusses the salient features of the physiology of breathing and sleep disturbances before and after LTX and its alterations during sleep.

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.

Surgical treatment of pulmonary hypertension: Lung transplantation

Pulmonary hypertension (PH) is a serious and progressive disorder that results in right ventricular dysfunction that lead to subsequent right heart failure and death. When untreated the median survival for these patients is 2.8 years. Over the past decade advances in disease specific medical therapy considerably changed the natural history. This is reflected in a threefold decrease in the number of patients undergoing lung transplantation for PH which used to be main stay of treatment. Despite the successful development of medical therapy lung transplant still remains the gold standard for patients who fail medical therapy. Referral for lung transplant is recommended when patients have a less than 2-3 years of predicted survival or in NYHA class III or IV. Both single and bilateral lung transplants have been successfully performed for PH but outcome analyses and survival comparisons generally favor a bilateral lung transplant.

Lung transplantation and pulmonary hypertension

The presence of pulmonary hypertension affects lung transplantation in multiple ways, from patient selection, transplant risks, type of transplant, intraoperative management, to transplant outcome. A working knowledge of natural disease progression, the latest medical treatment options, and transplant outcome is critical in patient selection, and a good understanding of the transplant process, including the new transplant allocation system, is important for physicians involved in the care of patients with pulmonary arterial hypertension. The complexity of these factors underscores the importance of good communication between referring physicians and transplant centers.

Surgical therapies for pulmonary arterial hypertension

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

Pharmacotherapy for idiopathic pulmonary arterial hypertension during the past 25 years

OBJECTIVE

To review the current pharmacotherapy for idiopathic pulmonary arterial hypertension (IPAH).

METHODS

A search of the primary literature was conducted by using MEDLINE, the National Institutes of Health medical research Web site (www.clinicaltrials.gov), and the United States Food and Drug Administration's Center for Drug Evaluation and Research Web site (www.fda.gov/cder).

RESULTS

Until the early 1980s, conventional therapy for IPAH consisted of anticoagulation, diuretics, digitalis extracts, and supplemental oxygen, yet the 5-year mortality rate remained at 66%. Calcium channel blocker therapy was introduced with the hope that it would improve survival in patients with IPAH, but it was found to be effective in only approximately 25% of patients. In 1996, intravenous epoprostenol was the first drug to show long-term benefit on hemodynamics, exercise capacity, and survival. However, administration of epoprostenol requires a permanently indwelling central venous catheter, and tachyphylaxis is common, necessitating continuous dosage escalations. Subsequently, treprostinil, a prostacyclin analog of epoprostenol that can be administered by continuous subcutaneous infusion, was introduced, followed by aerosolized iloprost, a prostacyclin analog for inhalation. An increasing understanding of the multiple pathogeneses of IPAH led to the discovery of another target for drug therapy, and bosentan, an orally administered agent, became the first endothelin-receptor antagonist approved for treatment of IPAH. Most recently, the phosphodiesterase inhibitor, sildenafil, has received approval from the United States Food and Drug Administration for the treatment of IPAH.

CONCLUSION

Recently developed pharmacotherapies offer greater effectiveness and safety than traditional agents for the treatment of IPAH.

Pulmonary arterial hypertension

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

Previous thoracic surgery does not increase peri-operative mortality in pediatric heart-lung transplant recipients

BACKGROUND

Heart-lung transplant (HLT) is indicated in select children with end-stage cardiopulmonary disease. We sought to determine whether previous thoracic surgery increases peri-operative morbidity and mortality.

METHODS

Retrospective data were analyzed using unpaired Student's t-test and Fisher's exact test. Results are reported as mean +/- SD. Peri-operative mortality was defined as death at </=30 days post-transplant.

RESULTS

From August 1993 through April 2001, 13 patients (mean age 7.9 +/- 5.3 years; 9 girls, 4 boys) underwent HLT at our center. Eight of 13 (62%) had previous thoracic surgery and 5 of 13 (38%) did not. Interval of last surgery to transplant date was 45.5 +/- 26.4 months (range 6 to 79 months). We compared HLT patients who had previous thoracic surgery to HLT recipients who did not. There was no significant difference in weight (18.6 +/- 14.3 vs 36.5 +/- 20.7 kg, p = 0.09), age (6.5 +/- 4.5 vs 10.2 +/- 6.1 years, p = 0.23) or duration of intubation (14.1 +/- 12.9 vs 17.0 +/- 30.3 days, p = 0.83). There were no caval or tracheal anastomotic stenoses in either group. There was no significant difference in blood products transfused </=48 hours after HLT: packed red blood cells (p = 0.16); fresh frozen plasma (p = 0.13); platelets (p = 0.59), and cryoprecipitate (p = 0.27). There was no difference in cardiopulmonary bypass time (129.3 +/- 48.2 vs 160.6 +/- 73.9 minutes, p 0.39); post-operative diaphragm dysfunction (4 of 8 vs 0 of 5, p = 0.1); re-exploration for bleeding (2 of 8 vs 1 of 5, p = 1.0); or peri-operative mortality (2 of 8 vs 0 of 5, p = 0.48).

CONCLUSIONS

We conclude that previous thoracic surgery in HLT recipients does not significantly increase blood product transfusion, cardiopulmonary bypass time or peri-operative mortality.

Interventional and surgical modalities of treatment for pulmonary arterial hypertension

Beyond medical therapy, different interventional and surgical approaches exist for treatment of pulmonary arterial hypertension (PAH). Atrial septostomy has been applied in patients with lack of response to medical therapy in the absence of other surgical treatment options. With growing experience, procedure-related death rates have been reduced to 5.4%, and the most suitable patient group has been identified among patients with a mean right atrial pressure between 10 and 20 mm Hg. Pulmonary endarterectomy is the accepted form of treatment for patients with chronic thromboembolic pulmonary hypertension. Establishing the diagnosis and the classification of the type of lesions by pulmonary angiography is crucial for optimal patient selection. Perioperative mortality rates have been reduced to <10% in experienced centers, and the hemodynamic improvement is dramatic and sustained. Lung and heart-lung transplantation remains the procedure of choice for patients unsuitable for other treatment modalities. Timing of the procedure is difficult because waiting times vary between centers and usually are in a high range. Early referral of patients unresponsive to other treatment forms is therefore of importance to avoid transplantation of patients with established significant comorbidity. The survival rate during the first five years after transplantation for PAH is intermediate among the lung diseases, lower than chronic obstructive pulmonary disease but higher than idiopathic pulmonary fibrosis.

Surgical Treatments/Interventions for Pulmonary Arterial Hypertension

While considerable advances have been achieved in the medical treatment of pulmonary arterial hypertension (PAH) over the past decade, surgical and interventional approaches continue to have important roles in those patients for whom medical therapy is unavailable or has been unsuccessful. These techniques include pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension, thoracic transplantation, and atrial septostomy. This chapter will provide evidence-based recommendations for the selection and timing of surgical and interventional treatments of PAH for physicians involved in the care of these complex patients.

Anesthetic management of the adult patient with congenital heart disease

As the number of CHD repairs in adults continues to increase, these operations will be performed in a wider variety of institutions and systems. Unfortunately, not all of these centers will have an optimal environment for correcting CHD in adults. This type of surgery is best accomplished in a facility specifically designed for treating adults with CHD. Optimal care of these patients is provided by cardiologists who are trained and experienced in pediatric and adult cardiology, by surgeons who are trained and experienced in treating CHD, and by anesthesiologists who are experienced in caring for adults with CHD. Whatever the setting, cardiac anesthesiologists involved in these cases must be thoroughly aware of the anesthetic implications for the unique pathophysiology of each patient, and they must not rely on their "usual" expectations of either true pediatric CHD or acquired adult heart disease.

Time-related changes in pulmonary function after conversion to tacrolimus in bronchiolitis obliterans syndrome

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) is a leading cause of morbidity and mortality after lung and heart-lung transplantation. Present treatment is directed at the augmentation of pharmacologic immunosuppression.

METHODS

This study examines the effect of substituting cyclosporine with tacrolimus on the forced expiratory volume in 1 second (FEV(1)) and on the forced expiratory flow between 25% and 75% of vital capacity (FEF(25%-75%)) in 32 patients who developed BOS. The proportional rates of decline of FEV(1) and FEF(25%-75%) before and after treatment with tacrolimus were calculated. The actuarial survival of responders and non-responders to tacrolimus was compared. Pre-operative and post-operative factors were investigated to determine any difference between the 2 groups.

RESULTS

There were significant reductions in the rates of decline of FEV(1) and FEF(25%-75%) when the rates in the 3 months before conversion to tacrolimus were compared with subsequent rates at 0 to 3 months, 3 to 6 months, 6 to 9 months and 9 to 12 months after conversion. The rates of decline of FEV(1) and FEF(25%-75%) in the 3 months before conversion were 0.11 liters/month and 0.13 liters/s per month, respectively. This compares with the rates of decline for FEV(1) and FEF(25%-75%) for the 3 months after conversion to tacrolimus of 0.04 liters/month (p = 0.023) and 0.04 liters/s per month (p = 0.022), respectively. The actuarial survival at 1 year from the time of conversion to tacrolimus for the responder sub-group and the non-responder sub-group were 89.2% and 75%, respectively, and at 4 years after conversion were 61.3% and 56.3%, respectively (p = 0.92).

CONCLUSIONS

Tacrolimus rescue therapy is effective at stabilizing lung function in patients with BOS, and this effect is apparent up to 12 months after conversion from cyclosporine.

Lung transplantation for pulmonary vascular disease

BACKGROUND

Pulmonary hypertension (PHT) is a lethal condition resulting in markedly diminished life expectancy. Continuous prostaglandin I2 infusion has made an important contribution to symptom management, but it is not a panacea. Lung or heart-lung transplantation remains an important treatment option for end-stage PHT patients unresponsive to prostaglandin I2. This study reviews the outcomes after transplantation for PHT in our program.

METHODS

A retrospective chart review was performed for 100 consecutive patients with either primary PHT (48%) or secondary PHT (52%) transplants since 1989. Living recipients were contacted to confirm health and functional status.

RESULTS

Fifty-five adult and 45 pediatric patients underwent 51 bilateral lung transplants, 39 single lung transplants, and 10 heart-lung transplants. Mean age was 23.7 years (range, 1.2 months to 54.8 years) and mean pre-transplant New York Heart Association class was 3.2. Pre-transplant hemodynamics revealed a mean right atrial pressure of 9.6+/-5.4 mm Hg and mean pulmonary artery pressure of 64+/-14.4 mm Hg. Hospital mortality was 17% with early death predominantly because of graft failure and infection. With an average follow-up of 5.0 years, 1- and 5-year actuarial survival was 75% and 57%, respectively. Mean pulmonary artery pressure on follow-up catheterization was 22+/-6.0 mm Hg, and mean follow-up New York Heart Association class was 1.3 (p < 0.001 for both compared with pre-transplant). Diagnosis and type of transplant did not confer a significant difference in survival between groups.

CONCLUSIONS

Whereas lung or heart-lung transplant for PHT is associated with higher early mortality than other pulmonary disease entities, it provides similar long-term outcomes with dramatic improvement in both quality of life and physiologic aspects.

Lung transplantation for primary and secondary pulmonary hypertension

BACKGROUND

Single lung transplantation (SLT) and bilateral lung transplantation (BLT) are routinely performed in patients with primary pulmonary hypertension (PPH) and secondary pulmonary hypertension (SPH). It is unclear which procedure is preferable. We reviewed our experience with lung transplants for PPH and SPH to determine if any advantage exists with SLT or BLT for either PPH or SPH.

METHODS

We reviewed the outcomes of all lung transplants performed for PPH or SPH for 4.5 years (July 1995 to January 2000). Survival was reported by the Kaplan-Meier method, and log rank analysis was used to determine significance. Statistical analyses of clinical data were performed using analysis of variance and chi2 analysis.

RESULTS

A total of 57 recipients met criteria for pulmonary hypertension with a mean pulmonary artery pressure of greater than or equal to 30 mm Hg. There were 15 patients with PPH and 40 patients with SPH. There were 6 patients who had SLTs and 9 patients who had BLTs in the PPH group; and there were 9 patients who had SLTs and 21 patients who had BLTs in the SPH group. We found a survival advantage for PPH patients who underwent BLTs at all time points up to 4 years (100% vs 67%; p < or = 0.02). There was no clear advantage to SLTs or BLTs for SPH. At 4 years there was a trend toward improved survival with SLTs (91% vs 75%) in SPH patients with a mean pulmonary artery pressure less than or equal to 40 mm Hg (p < or = 0.11) with equivalent survival (80%) in patients with a mean pulmonary artery pressure greater than or equal to 40 mm Hg. There was also a trend toward improved survival in patients with a mean pulmonary artery pressure greater than or equal to 40 mm Hg (PPH and SPH) with BLTs (88% vs 62%; p = 0.19). The incidence of rejection, infection, and other complications was comparable between SLTs and BLTs in each group.

CONCLUSIONS

We believe that BLT is the procedure of choice for PPH. The procedure of choice is less clear for SPH. Patients with SPH and a mean pulmonary artery pressure greater than 40 mm Hg may benefit from a BLT and those with a mean pulmonary artery pressure less than or equal to 40 mm Hg may do better with an SLT; however, no clear advantage is seen.

Lung transplantation for primary pulmonary hypertension

Recent progress in medical therapies has diminished the role of transplantation in the management of PPH during the past decade. Drug therapy is not effective in some patients, responses to therapy are not sustained over time in others, and drug side effects eventually limit the benefits of treatment in a few more. Lung transplantation therefore ultimately is the only alternative for patients whose PPH is severe and cannot be managed medically. Choosing the right patient as a transplant candidate and the right time to make the initial referral to a transplant center are the crucial initial steps in the transplantation process, and the long waiting time before transplantation must be integrated into this decision. The outcome of lung and heart-lung transplantation for PHH has been good but sobering. Functional recovery has been excellent, but long-term survival results have been limited by the high prevalence of chronic allograft rejection.

Pulmonary hypertension: diagnostics and therapeutics

Pulmonary hypertension (PH) may develop because of a spectrum of insults to the lungs; in some patients, there seems to be no cause. Noninvasive tests, such as standard chest radiography, electrocardiography, and transthoracic Doppler echocardiography, provide effective screening if PH is suspected. This synopsis focuses on these screening studies and the more common clinical problems, including primary cardiac abnormalities, obstructive sleep apnea, chronic pulmonary embolism, pulmonary parenchymal problems, connective tissue disorders, cirrhosis with portal hypertension, and use of appetite suppressants, that should be considered when PH exists. Treatment options for PH, including intravenous prostacyclin (epoprostenol), and investigational agents such as subcutaneous or oral prostacyclin analogues and oral endothelin receptor antagonists are described.