Adverse outcomes associated with pulmonary hypertension in chronic obstructive pulmonary disease after bilateral lung transplantation

The Incidence and Prevalence of Pulmonary Hypertension in the COPD Population: A Systematic Review and Meta-Analysis

Purpose

Chronic obstructive pulmonary disease (COPD)-related pulmonary hypertension (PH) is one of the most common comorbidities of COPD, and often leads to a worse prognosis. Although the estimated prevalence and risk factors of COPD-related PH have been widely reported, these results have not been well integrated. This study aimed to review the worldwide incidence and prevalence of COPD-related PH and explore possible factors affecting its prevalence.

Patients and Methods

We searched four electronic databases (Web of Science, Embase, Cochrane, and MEDLINE) to identify all observational studies on the prevalence of COPD-related PH from database creation until July 20, 2021. Eligibility screening, quality assessment, and data extraction of the retrieved studies were independently conducted by two reviewers. Meta-analyses were performed to determine the prevalence of PH in the COPD population. Random-effects meta-regression model analyses were conducted to investigate the sources of heterogeneity.

Results

Altogether, 38 articles were included in the meta-analyses. The pooled prevalence was 39.2% (95% CI: 34.0–44.4, I² = 97.6%) for COPD-related PH. Subgroup analyses showed that the prevalence of PH increased with COPD severity, where the majority (30.2%) had mild PH and the minority had severe PH (7.2%). Furthermore, we found a significant regional difference in the prevalence of COPD-related PH (P = 0.000), which was the highest in Africa (64.0%) and the lowest in Europe (30.4%). However, stratified studies on other factors involving mean age, sex, enrolment time, participant recruitment settings, and PH diagnostic methods showed no significant differences in prevalence (P >0.05).

Conclusion

The global incidence of PH in the COPD population is very high, and there are significant regional and international variations. Patients with COPD should be screened for PH and contributing risk factors to reduce the burden on individuals and society.

Association of Pulmonary Hypertension with Survival and Neurologic Outcomes in Adults with In-Hospital Cardiac Arrest

BACKGROUND

Pulmonary hypertension (PH) has been associated with poor survival in multiple cardiopulmonary conditions, however its association with outcomes in cardiac arrest remains unknown. We aimed to evaluate the association of PH with survival and neurologic outcomes in adults with in-hospital cardiac arrest (IHCA).

METHODS

The study population included adults with IHCA undergoing resuscitation at an academic tertiary medical center from 2011-2019. Patients were classified based upon the presence versus absence of PH, defined as a pulmonary artery systolic pressure > 35mmHg on pre-arrest echocardiogram. Survival to discharge and favorable neurological outcome (defined as a Glasgow Outcome Score of 4-5) served as the primary and secondary outcomes of interest respectively.

RESULTS

Of the 371 patients studied, 203 (54.7%) had PH while 168 (45.3%) did not. Patients with PH had higher Charlson Comorbidity Score with higher rates of multiple baseline comorbidities. They also had worse multi-chamber enlargement, left ventricular diastolic dysfunction, right ventricular systolic dysfunction, and valvular heart disease compared to non-PH patients. Rates of survival to discharge (11.5% vs 10.9%, p=0.881) and favorable neurologic outcome (8.0% vs 6.2%, p=0.550) were similar in PH and non-PH patients respectively. In multivariable analysis, PH was not associated with survival to discharge (OR 1.23, 95%CI 0.57-2.65) or favorable neurologic outcome (OR 1.69, 95%CI 0.64 - 4.45).

CONCLUSIONS

In this contemporary registry of adults with IHCA, while PH was associated with a higher risk patient profile, it was not associated with survival or neurologic outcomes in this population.

Accuracy of echocardiography and chest tomography for pulmonary hypertension screening in patients awaiting lung transplantation

OBJECTIVE

To examine the accuracy of a pulmonary hypertension screening strategy based on a combination of echocardiographic data and tomographic measurements (pulmonary artery diameter and pulmonary artery diameter to ascending aorta diameter ratio) in patients with chronic lung disease referred for lung transplantation.

METHODS

A retrospective observational study with patients with pulmonary emphysema or fibrosis referred for transplantation between 2012 and 2016. Pulmonary hypertension was defined as mean pulmonary artery pressure ≥25mmHg, or between 21 and 24mmHg, with pulmonary vascular resistance >3 Wood units on right heart catheterization. Tomographic measurements were made by two independent radiologists.

RESULTS

This sample comprised 13 patients with emphysema and 19 patients with pulmonary fibrosis. Of these, 18 had pulmonary hypertension. The level of agreement in tomographic measurements made by radiologists was high (intraclass correlation coefficients 0.936 and 0.940, for pulmonary artery diameter and pulmonary artery diameter to ascending aorta diameter ratio, respectively). Areas under the ROC curves constructed for pulmonary artery diameter, pulmonary artery diameter to ascending aorta diameter ratio, and pulmonary artery systolic pressure as predictors of pulmonary hypertension were 0.540, 0.629 and 0.783, respectively. The sensitivity, specificity and negative predictive value of pulmonary artery systolic pressure ≥40mmHg were 67%, 79% and 65%, respectively. The combined criterion (pulmonary artery diameter to ascending aorta diameter ratio >1 and/or pulmonary artery systolic pressure ≥40mmHg) achieved sensitivity of 72%, specificity of 79%, and a negative predictive value of 69%.

CONCLUSION

Measurements of pulmonary artery and ascending aorta diameter were highly reproducible. The association of pulmonary artery and aortic diameter >1 and/or pulmonary artery systolic pressure ≥40mmHg improved the sensitivity and the negative predictive value for pulmonary hypertension screening. This strategy demands prospective validation to assess safety and cost-effectiveness.

Lung Disease-Related Pulmonary Hypertension

Patients with advanced lung disease can develop pulmonary hypertension and succumb to right ventricular failure/cor pulmonale. Patients with pulmonary hypertension owing to chronic lung disease, or World Health Organization group 3 pulmonary hypertension, are more limited and carry a high risk of mortality. Adjunctive therapies remain the cornerstones of treatment. Recent evidence suggests that inhaled pulmonary vasodilator therapy can be helpful in patients with pulmonary hypertension owing to interstitial lung disease. Lung transplantation may be the only life-saving option in select patients, whereas palliative care and hospice should be sought for those who are not candidates as the disease progresses.

Consensus document for the selection of lung transplant candidates: An update from the International Society for Heart and Lung Transplantation

Tens of thousands of patients with advanced lung diseases may be eligible to be considered as potential candidates for lung transplant around the world each year. The timing of referral, evaluation, determination of candidacy, and listing of candidates continues to pose challenges and even ethical dilemmas. To address these challenges, the International Society for Heart and Lung Transplantation appointed an international group of members to review the literature, to consider recent advances in the management of advanced lung diseases, and to update prior consensus documents on the selection of lung transplant candidates. The purpose of this updated consensus document is to assist providers throughout the world who are caring for patients with pulmonary disease to identify potential candidates for lung transplant, to optimize the timing of the referral of these patients to lung transplant centers, and to provide transplant centers with a framework for evaluating and selecting candidates. In addition to addressing general considerations and providing disease specific recommendations for referral and listing, this updated consensus document includes an ethical framework, a recognition of the variability in acceptance of risk between transplant centers, and establishes a system to account for how a combination of risk factors may be taken into consideration in candidate selection for lung transplantation.

Chronic Obstructive Pulmonary Disease and Lung Transplantation

Lung transplantation (LTx) has been a viable option for patients with end-stage chronic obstructive pulmonary disease (COPD), with more than 20,000 procedures performed worldwide. Survival after LTx lags behind most other forms of solid-organ transplantation, with median survival for COPD recipients being a sobering 6.0 years. Given the limited supply of suitable donor organs, not all patients with end-stage COPD are candidates for LTx. We discuss appropriate criteria for accepting patients for LTx, as well as contraindications and exclusionary criteria. In the first year post-LTx, infection and graft failure are the leading causes of death. Beyond this chronic graft rejection-currently referred to as chronic lung allograft dysfunction-represents the leading cause of death at all time points, with infection and over time malignancy also limiting survival. Referral of COPD patients to a lung transplant center should be considered in the presence of progressing disease despite maximal medical therapy. As a rule of thumb, a forced expiratory volume in 1 second < 25% predicted in the absence of exacerbation, hypoxia (PaO₂ < 60 mm Hg/8 kPa), and/or hypercapnia (PaCO₂ > 50 mm Hg/6.6 kPa) and satisfactory general clinical condition should be considered the basic prerequisites for timely referral. We also discuss salient issues post-LTx and factors that impact posttransplant survival and morbidity such as infections, malignancy, renal insufficiency, and complications associated with long-term immunosuppression.

Clinical outcomes and survival following lung transplantation in patients with pulmonary Langerhans cell histiocytosis

BACKGROUND AND OBJECTIVE

Disease-specific outcomes following lung transplantation (LT) in patients with pulmonary Langerhans cell histiocytosis (PLCH) are not well established. We queried the Organ Procurement and Transplantation Network database to identify adult PLCH patients who had undergone LT in the United States.

METHODS

Overall survival data were analysed with Kaplan-Meier curves. Cox proportional hazard model was used to determine the effect of demographic, clinical and physiological variables on post-transplant survival.

RESULTS

A total of 87 patients with PLCH underwent LT in the United States between October 1987 and June 2017, accounting for 0.25% of the total LT during this period. The mean age at LT for PLCH patients was 49 years (range: 19-67 years), with a near equal gender distribution. Bilateral sequential LT was performed in 71 patients (82%). Pulmonary hypertension was present in 85% of patients, with a mean pulmonary artery pressure of 38.5 ± 14.1 mm Hg. The mean pre-transplant forced expiratory volume in 1 s (FEV₁ ) was 41 ± 21% predicted and the mean 6-min walk distance was 221 ± 111 m. Median post-LT survival for PLCH patients was comparable to patients with other lung diseases (5.1 vs 5.5 years, P = 0.76). The actuarial Kaplan-Meier post-LT survival for PLCH patients was 85%, 65%, 49% and 22% at 1, 3, 5 and 10 years, respectively. Female sex (hazard ratio (HR): 0.40, 95% CI: 0.22-0.72), pre-transplant serum bilirubin (HR: 1.66, 95% CI: 1.23-2.26) and serum creatinine (HR: 4.03, 95% CI: 1.01-14.76) were independently associated with post-LT mortality in our cohort.

CONCLUSION

Post-LT survival in patients with PLCH is similar to patients with other lung diseases and is significantly affected by patient gender.

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.

Transplant options for end stage chronic obstructive pulmonary disease in the context of multidisciplinary treatments

Lung transplantation (LTx) in advanced stage chronic obstructive pulmonary disease (COPD) patients is associated with significant improvement in lung function and exercise capacity. However, demonstration that the procedure also provides a survival benefit has been more elusive compared to other respiratory conditions. Identification of patients with increased risk of mortality is crucial: a low forced expiratory volume in 1 second (FEV₁) is perhaps the most common reason for referral to a lung transplant center, but in itself is insufficient to identify which COPD patients will benefit from LTx. Many variables have to be considered in the selection of candidates, time for listing, and choice of procedure: age, patient comorbidities, secondary pulmonary hypertension, the balance between individual and community benefit. This review will discuss patient selection, transplant listing, potential benefits and critical issues of bilateral (BLTx) and single lung (SLTx) procedure, donor-to-recipient organ size-matching; furthermore, it will describe LTx outcomes and its effects on recipient survival and quality of life.

Prognostic value of pre-transplant mean pulmonary arterial pressure in lung transplant recipients: a single-institution experience

Background

Currently, lung transplantation (LTX) is considered to be a curative treatment option in patients with end-stage lung disease. Although pulmonary hypertension (PH), confirmed by cardiac catheterization, is a prognostic factor in patients undergoing LTX, the prognostic value of PH in Asian lung transplant recipients remains uncertain. In this study, we aimed to determine whether PH before LTX may serve as a prognostic factor for survival in Asian patients.

Methods

The medical records of 50 patients [male, 27; female, 23; mean age, 51.0 (41.0-60.0) years], who received preoperative right heart catheterization (RHC) and echocardiography before single or double LTX at Severance Hospital between January 2010 and December 2014, were reviewed. The relationship between 1-year survival after LTX and PH [mean pulmonary arterial pressure (mPAP) ≥25 mmHg at rest] was evaluated.

Results

The mean right ventricular systolic pressure and mPAP were 48.5 (22.8) and 30.0 (24.0-40.0) mmHg. Of the 50 patients, 17 (34.0%) died within a year after LTX. The 1-year survival rate among patients with mPAP ≥25 mmHg (58.8%) was lower than the survival rate among patients with mPAP <25 mmHg (87.5%). Pre-transplantation mPAP of ≥25 mmHg was associated with post-transplantation survival [hazard ratio (HR), 4.832; 95% confidence interval (CI), 1.080-21.608, P=0.039]. The presence of preoperative PH was also associated with an increased risk of postoperative complications.

Conclusions

Confirmation of PH via preoperative cardiac catheterization was associated with the prognosis of the patient after LTX. Clinicians should consider the necessity for early transplantation surgery before the mPAP reaches ≥25 mmHg.

Noteworthy Literature Published in 2017 for Thoracic Transplantation Anesthesiologists

Thoracic organ transplantation constitutes a significant proportion of all transplant procedures. Thoracic solid organ transplantation continues to be a burgeoning field of research. This article presents a review of remarkable literature published in 2017 regarding perioperative issues pertinent to the thoracic transplant anesthesiologists.