Secondary pulmonary hypertension does not adversely affect outcome after single lung transplantation

Donor and recipient risk factors for the development of primary graft dysfunction following lung transplantation

Primary Graft Dysfunction (PGD) is a major cause of both short-term and long-term morbidity and mortality following lung transplantation. Various donor, recipient, and technical risk factors have been previously identified as being associated with the development of PGD. Here, we present a comprehensive review of the current literature as it pertains to PGD following lung transplantation, as well as discussing current strategies to mitigate PGD and future directions. We will pay special attention to recent advances in lung transplantation such as ex-vivo lung perfusion, thoracoabdominal normothermic regional perfusion, and up-to-date literature published in the interim since the 2016 ISHLT consensus statement on PGD and the COVID-19 pandemic.

Pulmonary Hypertension in Interstitial Lung Disease: Management Options to Move Beyond Supportive Care

Purpose of Review

This review delineates current diagnostic and management strategies for pulmonary hypertension due to interstitial lung disease (PH-ILD).

Recent Findings

The INCREASE trial, a phase III multicenter, randomized, placebo-controlled trial demonstrated both improved 6-min walk distance and decreased disease progression with inhaled treprostinil. This pivotal trial led to inhaled treprostinil becoming the first FDA approved medication for treatment of PH-ILD. The availability of this treatment has generated subsequent recommendations for the screening for PH in patients with ILD. As a result, it is becoming increasingly important for clinicians to gain awareness and familiarity with the evolving management options for PH-ILD.

Summary

The management of PH-ILD has its roots in goal-directed treatment of the underlying lung disease. However, recent medication advances and ongoing clinical studies are opening opportunities for more disease-specific treatment.

Single lung transplantation in patients with severe secondary pulmonary hypertension

BACKGROUND

The optimal transplant strategy for patients with end-stage lung disease complicated by secondary pulmonary hypertension (PH) is controversial. The aim of this study is to define the role of single lung transplantation in this population.

METHODS

We performed a retrospective study of lung transplant recipients using the Organ Procurement and Transplantation Network/United Network for Organ Sharing Standard Transplant Analysis and Research registry. Adult recipients that underwent isolated lung transplantation between May 2005 and June 2015 for end-stage lung disease because of obstructive or restrictive etiologies were identified. Patients were stratified by mean pulmonary artery pressure ([mPAP] ≥ or < 40 mm Hg) and by treatment-single (SOLT) or bilateral (BOLT) orthotopic lung transplantation. The primary outcome measure was overall survival (OS), which was estimated using the Kaplan-Meier method and compared by the log-rank test. To adjust for donor and recipient confounders, Cox proportional hazards models were developed to estimate the adjusted hazard ratio of mortality associated with elevated mPAP in SOLT and BOLT recipients.

RESULTS

A total of 12,392 recipients met inclusion criteria. Of recipients undergoing SOLT, those with mPAP ≥40 were shown to have lower survival, with 5-year OS of 43.9% (95% confidence interval 36.6-52.7; p = 0.007). Of recipients undergoing BOLT, OS was superior to SOLT, and no difference in 5-year OS between mPAP ≥ and <40 was observed (p = 0.15). In the adjusted analysis, mPAP ≥40 mm Hg was found to be an independent predictor for mortality in SOLT, but not BOLT recipients. This finding remained true on multivariable analysis. In patients undergoing SOLT, mPAP ≥40 was associated with an adjusted hazard ratio for mortality of 1.31 (1.08-1.59, p = 0.07). In BOLT, mPAP was not associated with increased hazard (adjusted hazard ratio 1.04, p = 0.48).

CONCLUSIONS

There is a reduced survival when a patient with severe secondary PH undergoes SOLT. This increased mortality hazard is not seen in BOLT. It appears that a BOLT may negate the adverse effect that severe PH has on OS, and may be superior to SOLT in patients with mPAP over 40 mm Hg.

The presence or severity of pulmonary hypertension does not affect outcomes for single-lung transplantation

Advanced lung disease (ALD) that requires lung transplantation (LTX) is frequently associated with pulmonary hypertension (PH). Whether the presence of PH significantly affects the outcomes following single-lung transplantation (SLT) remains controversial. Therefore, we retrospectively examined the outcomes of 279 consecutive SLT recipients transplanted at our centre, and the patients were split into four groups based on their mean pulmonary artery pressure values. Outcomes, including long-term survival and primary graft dysfunction, did not differ significantly for patients with versus without PH, even when PH was severe. We suggest that SLT can be performed safely in patients with ALD-associated PH.

Lung transplantation for interstitial lung disease

For selected parenchymal lung disease patients who fail to respond to medical therapy and demonstrate declines in function that place them at increased risk for mortality, lung transplantation should be considered. Lung transplantation remains a complex medical intervention that requires a dedicated recipient and medical team. Despite the challenges, lung transplantation affords appropriate patients a reasonable chance at increased survival and improved quality of life. Lung transplantation remains an appropriate therapeutic option for selected patients with parenchymal lung disease.

Pulmonary hypertension in idiopathic pulmonary fibrosis: a review

Idiopathic pulmonary fibrosis (IPF) is a progressive diffuse parenchymal disease with a poor prognosis. Pulmonary hypertension (PH) often complicates the course of IPF and may even be found in patients with preserved lung function. Possible pathogenetic mechanisms of PH in IPF include vascular destruction, pulmonary hypoxic vasoconstriction and vascular remodeling due to overexpression of cytokines and growth factors. PH in IPF patients is associated with decreased exercise capacity and a worse prognosis. Due to its prognostic significance, it seems important to investigate for PH in these patients. As the symptoms of PH in IPF are nonspecific, the development of PH in a patient with known IPF can be easily overlooked. Noninvasive methods provide clues for the diagnosis, but their sensitivity is limited. Doppler echocardiography is a useful tool for the detection of PH which also provides additional information regarding associated cardiac abnormalities. However, right heart catheterization remains the gold standard diagnostic test. Therapeutic options for PH in IPF are limited. Long-term oxygen administration for the correction of hypoxemia should be recommended. The availability of new pharmacological agents in the treatment of PH has raised the possibility of therapy in patients with IPF and associated PH. Whether these PH-targeted therapies may be of benefit in this patient group, in terms of improving functional outcomes and survival, remains uncertain.

Pulmonary hypertension in patients with interstitial lung diseases

Pulmonary hypertension (PH) in patients with interstitial lung diseases (ILDs) is not well recognized and can occur in the absence of advanced pulmonary dysfunction or hypoxemia. To address this topic, we identified relevant studies in the English language by searching the MEDLINE database (1966 to November 2006) and by individually reviewing the references of identified articles. Connective tissue disease-related ILD, sarcoidosis, idiopathic pulmonary fibrosis, and pulmonary Langerhans cell histiocytosis are the ILDs most commonly associated with PH. Pulmonary hypertension is an underrecognized complication in patients with ILDs and can adversely affect symptoms, functional capacity, and survival. Pulmonary hypertension can arise in patients with ILDs through various mechanisms, Including pulmonary vasoconstriction and vascular remodeling, vascular destruction associated with progressive parenchymal fibrosis, vascular inflammation, perivascular fibrosis, and thrombotic angiopathy. Diagnosis of PH in these patients requires a high index of suspicion because the clinical presentation tends to be nonspecific, particularly in the presence of an underlying parenchymal lung disease. Doppler echocardiography is an essential tool in the evaluation of suspected PH and allows ready recognition of cardiac causes. Right heart catheterization is needed to confirm the presence of PH, assess its severity, and guide therapy. Management of PH in patients with ILDs is guided by identification of the underlying mechanism and the clinical context. An increasing number of available pharmacologic agents in the treatment of PH allow possible treatment of PH in some patients with ILDs. Whether specific treatment of PH in these patients favorably alters functional capacity or outcome needs to be determined.

Impact of secondary pulmonary hypertension on lung transplant outcome

INTRODUCTION

Secondary pulmonary hypertension (SPH), defined as a mean pulmonary artery pressure (PAM) greater than 25 mm Hg, complicates end-stage lung diseases of varying etiology. Although previous studies have suggested that SPH does not adversely affect outcome, no study has assessed the impact of the degree of SPH.

METHODS

A retrospective review of the lung transplant database was used to identify patients who underwent either single-lung (SLT) or bilateral lung transplantation (BLT) complicated by SPH. SPH patients were stratified into low SPH (PAM = 30-40 mm Hg) and high SPH (PAM > or = 40 mm Hg). Each group was further sub-categorized into SLT or BLT. Patients with a heart-lung transplant or primary pulmonary hypertension were excluded. Recipients without pulmonary hypertension transplanted over the same time were used as controls. Data are reported as controls vs low SPH vs high SPH.

RESULTS

One hundred-four patients received lung transplants between August 1998 and March 2003. There were 45 patients (18 men and 27 women) with SPH. Of these, 28 patients had low SPH, and 17 patients had high SPH. Forty-two patients (18 men and 24 women) without PH were the controls. There were no significant differences between groups except pre-operative oxygen dependence (81% vs 100% vs 94%, respectively) and use of CPB (28.6% vs 57.1% vs 64.7%, respectively). PAO2-PaO2 gradients and PaO2/FIO2 ratios were significantly worse in the high SPH group (116.2 vs 132.9 vs 186.3; p < 0.006) and (277.8 vs 234.3 vs 214.4; p < 0.026) respectively. There was no statistical difference in length of mechanical ventilation or duration of intensive care unit stay between groups. PAMs were significantly different pre-operatively (22.2 +/- 0.8 vs 34.0 +/- 0.6 vs 47.8 +/- 2.0; p < 0.001) and post-operatively (20.9 +/- 1.1 vs 23.7 +/- 1.3 vs 24.8 +/- 2.1; p < 0.001). There were no operative deaths. There were 3 early deaths in the control group, 1 in the low SPH group, and 3 in the high SPH group, none were related to pulmonary hypertension. Actuarial survival at 12, 24, and 48 months was not significantly different among the groups nor between SLT or BLT with SPH.

CONCLUSION

Although SPH increases the risk of reperfusion injury; survival is equivalent with mild or moderate pulmonary hypertension. Either SLT or BLT may be used in patients with SPH without compromising outcome. This has the added benefit of expanding the donor pool.

Effect of preoperative pulmonary artery pressure on early survival after lung transplantation for idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is the second largest indication for lung transplantation worldwide. Average 90-day mortality rates for this procedure are 22%. It is unclear what factors predispose patients with IPF to this increased early posttransplant mortality. Pulmonary hypertension may increase the risk of development of early posttransplant complications through several mechanisms. We examined the effect of secondary pulmonary hypertension on 90-day mortality after lung transplantation for IPF.

METHODS

An International Society for Heart and Lung Transplant Registry cohort study of 830 patients with IPF transplanted from January 1995 to June 2002 was undertaken. Risk factors were assessed individually and adjusted for confounding by a multivariable logistic regression model.

RESULTS

In the univariate analysis, pulmonary hypertension and bilateral-lung transplantation were significant risk factors for increased 90-day mortality. Multivariate analysis confirmed that mean pulmonary artery pressure and bilateral procedure remain independent risk factors after adjustment for potential confounders. Recipient age, ischemia time, cytomegalovirus status mismatch, and donor age were not independent risk factors for early mortality.

CONCLUSIONS

Bilateral-lung transplantation carries a greater risk of early mortality than single-lung transplantation for IPF. Increasing pulmonary artery pressure is a risk factor for death after single-lung transplantation in IPF. Mean pulmonary artery pressure should be included in the overall risk assessment of patients with IPF evaluated for lung transplantation.

Impact of recipient age and procedure type on survival after lung transplantation for pulmonary fibrosis

BACKGROUND

The decision to perform single-lung (SLT) or bilateral sequential lung (BSLT) transplantation in patients with pulmonary fibrosis is controversial. Some centers use recipient age (<50 years) as a criterion to select BSLT over SLT, but the rationale for this approach is not well established.

METHODS

Eight hundred twenty-one patients (636 SLT, 185 BSLT), aged 30 to 69 years, who were recipients of transplants for pulmonary fibrosis in the United States between 1994 and 2000 were reported to the United Network for Organ Sharing. Survival was compared by procedure type within three age groups (30 to 49 years, 50 to 59 years, and 60 to 69 years) using the Kaplan-Meier method. Multivariate logistic regression analysis was used to calculate risk-adjusted mortality within 1-month after transplantation, and proportional hazards regression was used to calculate risk-adjusted mortality after 1 month.

RESULTS

Early (1-month) and late (3-year) survival in recipients aged 30 to 49 years was significantly better with SLT than BSLT (early, 90.9% versus 77.1%; late, 63.8% versus 46.2%, respectively; p = 0.02). Survival was also significantly better with SLT than BSLT at these time points in those patients aged 50 to 59 years (early, 89.5% versus 81.7%; late, 53.6% versus 46.7%, respectively; p = 0.03). When posttransplant survival was reanalyzed contingent on survival to 1 month, no significant difference in survival by procedure type (SLT versus BSLT) was detected for any age group. Multivariate analysis of survival, adjusted for other known risk factors, as well as propensity analysis, yielded similar results.

CONCLUSIONS

Patients younger than 60 years of age who were recipients of transplants for pulmonary fibrosis appear to have better survival with SLT than with BSLT. Although the basis for this observation is unclear, events occurring in the early period (first month) after transplantation may play a role. Further studies will be needed, but these data do not appear to support the preferential use of BSLT for younger patients with pulmonary fibrosis.

Lung transplantation and interstitial lung disease

PURPOSE OF REVIEW

Interstitial lung disease includes a heterogeneous group of disorders that leads to respiratory insufficiency and death in a significant number of patients. Lung transplantation is a therapeutic option in select candidates.

RECENT FINDINGS

The indications, transplant procedure options, and outcomes continue to evolve. Various recipient comorbidities influence the choice of procedure in patients with interstitial lung disease. Single lung transplants are used as the procedure of choice and bilateral transplants are reserved for patients with suppurative lung disease and patients with pulmonary hypertension. Issues unique to patients with interstitial lung disease affect the morbidity, mortality and recurrence of the disease.

SUMMARY

Lung transplantation is an effective therapy for respiratory failure in interstitial lung disease with survival following transplant being similar to that achieved in transplant recipients with other diseases.

Lung transplantation for interstitial lung disease

Lung transplantation remains the only therapeutic option shown to improve survival for many end-stage interstitial lung diseases. Although idiopathic pulmonary fibrosis is the most common indication, transplantation has been performed for many other diseases. This article reviews the current indications and outcomes for the procedure and problems encountered in lung transplantation for interstitial lung diseases. The role of transplant for specific diseases also is discussed.

Anesthetic implications for lung transplantation

Anesthetic challenges regarding lung transplantation are related to the expanded spectrum of diseases for which lung transplantation is offered and to the interval changes in health status likely to occur as patients wait longer for an organ to become available. Particular attention to avoiding or reducing the impact of increases in pulmonary vascular resistance and right heart failure are important and may necessitate cardiopulmonary bypass. Intraoperative and postoperative ventilator management should account for differences in pulmonary compliance after the new lung is implanted. Minimizing intravenous fluids without compromising end organ perfusion may avoid or reduce postoperative respiratory insufficiency.

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.

Critical care issues in lung and heart transplantation

Although much has been accomplished in HTx and LTx in the past few decades, much remains to be conquered. It is an ever-changing, always fascinating field. Though science and technology know no limits, the primary limitation of HTx and LTx continues to be the availability of donor organs. One can only hope that further advances in educating the public will help close the large gap between the list of those waiting and the organs available for transplantation.

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 in interstitial lung disease

Interstitial lung disease is a heterogeneous group of illnesses, some of which may progress to a fibrosing stage and cause respiratory failure. For selected candidates, lung transplantation is the ultimate therapeutic option. We review data on lung transplantation for various interstitial lung diseases. We address indications, procedures, and outcomes for patients undergoing transplantation. Unique issues affecting morbidity, mortality, and recurrence of disease are discussed. We review the literature of transplantation for specific interstitial lung diseases and the outcomes of transplantation for interstitial lung diseases. Candidates with idiopathic pulmonary fibrosis experience high mortality on the waiting list, but derive significant survival benefit from lung transplantation. Recurrence is reported for several interstitial lung diseases after lung transplantation. Survival with lung transplantation for interstitial lung diseases is comparable with that attained in recipients with other indications. Lung transplantation is a well-tolerated, effective therapy for respiratory failure in interstitial lung disease.