Burger, Charles D.

The 6-minute walk test is an easy to perform and practical test that has been used in the assessment of patients with a variety of cardiopulmonary diseases including pulmonary arterial hypertension. The correlation with maximal cardiac output renders the test an indirect measure of right ventricular function in patients with significant pulmonary arterial hypertension. The test has been employed in the majority of studies evaluating the efficacy of pulmonary arterial vasodilators. In addition, the distance walked has been demonstrated to correlate with prognosis. An understanding of the 6-minute walk test indications, logistics, limitations, and interpretation is important to the clinician utilizing this test to evaluate patients with pulmonary arterial hypertension.

Background: Portopulmonary hypertension (POPH) is defined as pulmonary arterial hypertension (PAH) in the context of portal hypertension. Severe POPH has been considered an absolute contraindication of orthotopic liver transplantation (OLT).Objective: Since there are no definitive guidelines for the immediate preoperative, intraoperative, and postoperative evaluation and treatment of POPH patients, we have used published literature along with our experience to review current knowledge in this area.Summary: Moderate-to-severe POPH has important consequences in the perioperative management of candidates for OLT. Adequate right ventricular function is critical to survive the hemodynamic burden of OLT. Immediate preoperative assessment of hemodynamics; careful intraoperative monitoring and management of volume status, pressure changes, and ventricular function; and postoperative transitions of PAH-specific therapy are key components to successful OLT. We emphasize the advantages of the echocardiogram during all of these phases and stress the importance of a team approach to plan care and respond to the multiple challenges of OLT in POPH.

Background: Treprostinil is a prostacyclin analogue that directly vasodilates pulmonary and systemic arterial vascular beds. The United States Food and Drug Administration approved inhaled treprostinil in July 2009 for the treatment of group 1 pulmonary arterial hypertension. Inhaled treprostinil avoids issues with continuous infusion prostanoids. This study describes a single institutional experience with inhaled treprostinil. Methods: This was a retrospective review of group 1 pulmonary arterial hypertension patients receiving inhaled treprostinil from July 2009 through September 2015. Patient demographics, vital signs, prognostic indicators, pulmonary arterial hypertension assessments, treprostinil dosing, pulmonary arterial hypertension medications, and physician assessment were collected. Prognostic indicators and the physician assessment were used to assess treatment response. A modified Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management (REVEAL) risk score was calculated prior to and after initiation of inhaled treprostinil. Results: The mean time on inhaled treprostinil for the 16 patients was 21 ± 17 months. A total of 31% discontinued treatment. The New York Heart Association Functional Class, right ventricular size, and right ventricular function improved after inhaled treprostinil. Directional improvement in B-type natriuretic peptide, 6-minute walk distance, right arterial pressure and mean pulmonary artery pressure were also observed. The mean modified REVEAL risk score (RRS) was 7 ± 3 at baseline. The RRS decreased in 7 of the 11 patients that improved and remained stable in 2 patients. Conclusion: The majority of patients in this consecutive series receiving inhaled treprostinil tolerated treatment. Most patients remained on therapy for over 12 months. Clinical assessments of disease severity all changed directionally toward improvement and the overall risk assessment was improved or stable in 56% by the RRS.

Pulmonary arterial hypertension (PAH) is a progressive disease that requires validated biomarkers of disease severity. While PAH is defined hemodynamically by right heart catheterization (RHC), brain natriuretic peptide (BNP) is recommended by guidelines to assess disease status. Retrospectively collected data in 138 group 1 PAH patients were examined for the correlation of BNP levels to simultaneously obtained right heart catheterization (RHC). Patients were mostly Caucasian women, with functional class III symptoms, mean BNP of 406 ± 443 pg/mL, and an average right atrial pressure (RAP) of 9.9 ± 5.7 mm Hg and mean pulmonary artery pressure (mPAP) of 47.3 ± 14.7 mm Hg. Significant correlation was demonstrated between BNP and RAP (p = 0.021) and mPAP (p = 0.003). Additional correlation was seen with right heart size on echocardiography: right atrial (RAE; p = 0.04) and right ventricular enlargement (p = 0.03). An increased BNP level was an independent predictor of mortality (p < 0.0001), along with RAP (p = 0.039) and RAE (p = 0.018). Simultaneous collection of BNP at the time of RHC confirmed the correlation of BNP with right heart hemodynamics. The current results reinforce the use of BNP level as a continuous variable to assess disease severity in group 1 PAH.