Survival in portopulmonary hypertension: Outcomes of the United Kingdom National Pulmonary Arterial Hypertension Registry

The Use of Risk Assessment Tools and Prognostic Scores in Managing Patients with Pulmonary Arterial Hypertension

PURPOSE OF REVIEW

Pulmonary arterial hypertension (PAH) is a chronic, progressive, and incurable disease with significant morbidity and mortality. Despite increasingly available treatment options, PAH patients continue to experience disease progression and increased rates of hospitalizations due to right heart failure. Physician's ability to comprehensively assess PAH patients, determine prognosis, and monitor disease progression and response to treatment remains critical in optimizing outcomes.

RECENT FINDINGS

Risk assessment in PAH should include a range of clinical, hemodynamic, and exercise parameters, performed in a serial fashion over the course of treatment. Approaches to risk assessment in PAH patients include the use of risk variables, scores, and equations that stratify the impact of both modifiable (e.g., 6-min walk distance, functional class, brain natriuretic peptide), and non-modifiable (e.g., age, gender, PAH etiology) risk factors. Such tools allow physicians to better determine prognosis, allocate treatment resources, and enhance the consistency of treatment approaches across providers. Comprehensive and accurate risk prediction is essential to make individualized treatment decisions and optimizing outcomes in PAH.

Diagnosis of pulmonary hypertension

A revised diagnostic algorithm provides guidelines for the diagnosis of patients with suspected pulmonary hypertension, both prior to and following referral to expert centres, and includes recommendations for expedited referral of high-risk or complicated patients and patients with confounding comorbidities. New recommendations for screening high-risk groups are given, and current diagnostic tools and emerging diagnostic technologies are reviewed.

Treatment Barriers in Portopulmonary Hypertension

Portopulmonary hypertension (PoPH) is a form of pulmonary arterial hypertension (PAH) that can develop as a complication of portal hypertension. Treatment of PoPH includes PAH-specific therapies, and in certain cases, such therapies are necessary to facilitate a successful liver transplantation. A significant number of barriers may limit the adequate treatment of patients with PoPH and explain the poorer survival of these patients when compared to patients with other types of PAH. Until recently, only one randomized controlled trial has included PoPH patients, and the majority of treatment data have been derived from relatively small observational studies. In the present article, we review some of the barriers in the treatment of patients with PoPH and implications for liver transplantation.

Diagnosis of pulmonary hypertension

A revised diagnostic algorithm provides guidelines for the diagnosis of patients with suspected pulmonary hypertension, both prior to and following referral to expert centres, and includes recommendations for expedited referral of high-risk or complicated patients and patients with confounding comorbidities. New recommendations for screening high-risk groups are given, and current diagnostic tools and emerging diagnostic technologies are reviewed.

Validation of claims-based algorithms for pulmonary arterial hypertension

Administrative claims studies do not adequately distinguish pulmonary arterial hypertension (PAH) from other forms of pulmonary hypertension (PH). Our aim is to develop and validate a set of algorithms using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes and electronic medical records (EMR), to identify patients with PAH. From January 2012 to August 2015, the EMRs of patients with ICD-9-CM codes for PH with an outpatient visit at the University of Texas Medical Branch were reviewed. Patients were divided into PAH or non-PAH groups according to EMR encounter diagnosis. Patient demographics, echocardiography, right heart catheterization (RHC) results, and PAH-specific therapies were assessed. RHC measurements were reviewed to categorize cases as hemodynamically determined PAH or not PAH. Weighted sensitivity, specificity, and positive and negative predictive values were calculated for the developed algorithms. A logistic regression analysis was conducted to determine how well the algorithms performed. External validation was performed at the University of Virginia Health System. The cohort for the development algorithms consisted of 683 patients with PH, PAH group (n = 191) and non-PAH group (n = 492). A hemodynamic diagnosis of PAH determined by RHC was recorded in the PAH (26%) and non-PAH (3%) groups. The positive predictive value for the algorithm that included ICD-9-CM and PAH-specific medications was 66.9% and sensitivity was 28.2% with a c-statistic of 0.66. The positive predictive value for the EMR-based algorithm that included ICD-9-CM, EMR encounter diagnosis, echocardiography, RHC, and PAH-specific medication was 69.4% and a c-statistic of 0.87. A validation cohort of 177 patients with PH examined from August 2015 to August 2016 using EMR-based algorithms yielded a similar positive predictive value of 62.5%. In conclusion, claims-based algorithms that included ICD-9-CM codes, EMR encounter diagnosis, echocardiography, RHC, and PAH-specific medications better-identified patients with PAH than ICD-9-CM codes alone.

Prognostic Value of Follow-Up Hemodynamic Variables After Initial Management in Pulmonary Arterial Hypertension

Background:

Hemodynamic variables such as cardiac index and right atrial pressure have consistently been associated with survival in pulmonary arterial hypertension (PAH) at the time of diagnosis. Recent studies have suggested that pulmonary arterial compliance may also predict prognosis in PAH. The prognostic importance of hemodynamic values achieved after treatment initiation is less well established.

Methods:

Our objective was to evaluate the prognostic importance of clinical and hemodynamic variables during follow-up, including pulmonary arterial compliance, after initial management in PAH. We evaluated incident patients with idiopathic, drug- and toxin-induced, or heritable PAH enrolled in the French pulmonary hypertension registry between 2006 and 2016 who had a follow-up right-sided heart catheterization (RHC). The primary outcome was death or lung transplantation. We used stepwise Cox regression and the Kaplan-Meier method to assess variables obtained at baseline and at first follow-up RHC.

Results:

Of 981 patients, a primary outcome occurred in 331 patients (33.7%) over a median follow-up duration of 2.8 years (interquartile range, 1.1–4.6 years). In a multivariable model considering only baseline variables, no hemodynamic variables independently predicted prognosis. Median time to first follow-up RHC was 4.6 months (interquartile range, 3.7–7.8 months). At first follow-up RHC (n=763), New York Heart Association functional class, 6-minute walk distance, stroke volume index (SVI), and right atrial pressure were independently associated with death or lung transplantation, adjusted for age, sex, and type of PAH. Pulmonary arterial compliance did not independently predict outcomes at baseline or during follow-up. The adjusted hazard ratio for SVI was 1.28 (95% confidence interval, 1.11–1.49; P <0.01) per 10-mL/m 2 decrease and for right atrial pressure was 1.05 (95% confidence interval, 1.02–1.09; P <0.01) per 1–mm Hg increase. Among patients who had 2 (n=355) or 3 (n=193) low-risk prognostic features at follow-up, including a cardiac index ≥2.5 L·min −1 ·m −2 , 6-minute walk distance >440 m, and New York Heart Association class I or II functional class, lower SVI was still associated with higher rates of death or lung transplantation ( P <0.01).

Conclusions:

SVI and right atrial pressure were the hemodynamic variables that were independently associated with death or lung transplantation at first follow-up RHC after initial PAH treatment. These findings suggest that the SVI could be a more appropriate treatment target than cardiac index in PAH.

Hepatopulmonary Syndrome and Portopulmonary Hypertension: Implications for Liver Transplantation

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PoPH) represent serious pulmonary complications of advanced liver diseases. Orthotopic liver transplantation (OLT) is capable of completely resolving the underlying abnormalities associated with HPS. On the other hand, post-OLT response in patients with PoPH is less predictable, although heavily influenced by pre-OLT mean pulmonary arterial pressure. It remains the case that the opportunity to reverse 2 potentially fatal organ dysfunctions in the liver and the lung make HPS and PoPH more than worthy for further clinical investigations.