Citations

AbstractThe prevalence of acute vasodilator response (AVR) to inhaled nitric oxide (iNO) during right heart catheterization (RHC) is 12% in idiopathic pulmonary arterial hypertension (IPAH). AVR, however, is reportedly lower in other disease‐associated pulmonary arterial hypertension (PAH), such as connective tissue disease (CTD). The prevalence of AVR in patients on PAH therapy (prevalent cases) is unknown. We sought to determine AVR prevalence in Group 1 PH in the PVDOMICS cohort of incident and prevalent patients undergoing RHC. AVR was measured in response to 100% O2 and O2 plus iNO, with positivity defined as (1) decrease in mean pulmonary artery pressure (mPAP) by ≥10 mmHg to a value ≤40 mmHg, with no change or an increase in cardiac output (definition 1); or (2) decrease in mPAP by ≥12% and pulmonary vascular resistance by ≥30% (definition 2). AVR rates and cumulative survival were compared between incident and prevalent patients. In 338 mainly prevalent (86%) patients, positive AVR to O2‐only was <2%, and 5.1% to 16.9%, based on definition 1 and 2 criteria, respectively; following O2 + iNO. IPAH AVR prevalence (4.1%–18.7%) was similar to prior reports. AVR positivity was 7.7% to 15.4% in mostly CTD‐PAH prevalent cases, and 2.6% to 11.8% in other PAH groups. Survival was 89% in AVR responders versus 77% in nonresponders from PAH diagnosis, and 91% versus 86% from PVDOMICS enrollment (log‐rank test p = 0.04 and p = 0.05, respectively). In conclusion, AVR in IPAH patients is similar to prior studies. AVR in non‐IPAH patients was higher than previously reported. The relationship between PAH therapy, AVR response, and survival warrants further investigation.

AbstractPulmonary arterial hypertension (PAH) is a rare, life‐limiting disease. PAH registries provide real‐world data that complement clinical trial data and inform treatment decisions. The TRIO comprehensive, integrated patient data repository (TRIO CIPDR), is an innovative US repository capturing data on contemporary patients diagnosed with pulmonary hypertension and receiving US Food and Drug Administration‐approved PAH therapies. This repository uniquely combines clinical data from electronic medical records with the ability to track drug‐prescription and drug‐dispensing characteristics, and includes 946 adult patients with PAH (data collected January 2019 to December 2020) enrolled from nine representative US specialist tertiary care centers. Potentially eligible patients were identified based on dispensing data from specialty pharmacies. Hemodynamic and clinical data, as well as dispensing information on prescribed PAH medications, were provided by tertiary centers. At enrollment, 75% of patients were female, 67% were White, median age at PAH diagnosis was 53 years (median time from diagnosis to enrollment was 5 years), and 37% were obese. Comorbidity profiles were as expected for a PAH population, although the proportion with atrial fibrillation (34%) was higher than expected. Overall, 38% of patients had idiopathic PAH and 30% had connective tissue disease‐related PAH. Among 917 patients receiving PAH‐specific therapy, 40% were on monotherapy, 43% on dual therapy, and 17% on triple therapy. Longitudinal data from this repository will allow tracking of the PAH treatment journey in relation to clinical characteristics and outcomes.

Introduction: Breathing efficiency (V E /VCO 2 slope or nadir) predicts mortality in heart failure (HF). The usual pattern of V E /VCO 2 vs. exercise intensity is a characteristic “shallow bowl” configuration allowing estimate of a V E vs. VCO 2 slope both in normal controls (C) and HF patients. Slope or nadir in HF is generally > 33 vs. 25-30 in C. This pattern of V E /VCO 2 may not be true for other CV diseases. Objective: Compare V E /VCO 2 versus exercise time curves in patients with history of chronic thromboembolic pulmonary hypertension type 4 (PHT4) to HF and C referred for dyspnea on exertion. Methods: We identified 40 consecutive cases of PHT4 versus 40 HF and 40 C over the same age range retrospectively selected from our cardiopulmonary exercise test (CPX) database. V E /VCO 2 was plotted against exercise time (minutes of exercise ≈ METs), and groups were compared statistically for V E /VCO 2 and peak VO 2 by ANOVA followed with Tukey test, with significance set at P < .05. Results: Figure shows higher V E /VCO 2 in PHT4 vs. HF and C with a different pattern vs. exercise intensity. In severe cases (example shown) V E /VCO 2 may increase continuously without plateau reaching peak values > 80. There was statistically significant difference between peak VO 2 between C group vs HF and PHT4, but not among HF and PHT4, although V E /VCO 2 was significant different among the three groups. Age and sex was not different among them. Conclusion: V E /VCO 2 was elevated in PHT4 compared to HF and C. We interpret continuously increasing V E /VCO 2 as a marker of progressively worsening ventilation: perfusion mismatch. Interpretation of V E /VCO 2 in PHT4 cannot be based simply on nadir or slope as in HF, but a plot of the data should be visually examined to gain full understanding of the ventilatory abnormality.

AbstractRight heart (RH) structure and function are major determinants of symptoms and prognosis in pulmonary arterial hypertension (PAH). RH imaging provides detailed information, but evidence and guidelines on the use of RH imaging in treatment decisions are limited. We conducted a Delphi study to gather expert opinion on the role of RH imaging in decision‐making for treatment escalation in PAH. A panel of 17 physicians with expertise in PAH and RH imaging used three surveys in a modified Delphi process to reach consensus on the role of RH imaging in PAH. Survey 1 used open‐ended questions to gather information. Survey 2 contained Likert scale and other questions intended to identify consensus on topics identified in Survey 1. Survey 3 contained Likert scale questions derived from Survey 2 and summary information on the results of Survey 2. The Delphi panel reached consensus that RH imaging is likely to improve the current risk stratification algorithms and help differentiate risk levels in patients at intermediate risk. Tricuspid annular plane systolic excursion, right ventricular fractional area change, right atrial area, tricuspid regurgitation, inferior venae cavae diameter, and pericardial effusion should be part of routine echocardiography in PAH. Cardiac magnetic resonance imaging is valuable but limited by cost and access. A pattern of abnormal RH imaging results should prompt consideration of hemodynamic evaluation and possible treatment escalation. RH imaging is an important tool for decisions about treatment escalation in PAH, but systematically collected evidence is needed to clarify its role.

AbstractChronic thromboembolic pulmonary hypertension (CTEPH) is believed to involve both vascular obstruction and vasoconstriction; hence, pulmonary vasodilators such as riociguat may be beneficial. Acute vasoreactivity testing (AVT) is seldom performed routinely in CTEPH patients, so there is limited understanding of the frequency and significance of an acute vasodilator response. Systematic vasodilator testing with oxygen (O2) and oxygen plus inhaled nitric oxide (O2 + iNO) was performed as part of the Pulmonary Vascular Disease Omics (PVDOMICS) NHLBI project, providing an opportunity to examine AVT responses in CTEPH. Patients with CTEPH enrolled in PVDOMICS (n = 49, 40 with prevalent CTEPH [82%]) underwent right heart catheterization including AVT with O2 and O2 + iNO. Hemodynamics were obtained at baseline and with each challenge. Fourteen of 49 patients (29%) had >20% drop in pulmonary vascular resistance (PVR) with O2. With O2 + iNO, 30/49 (61%) had >20% drop in PVR, 20% had >20% drop in mean pulmonary artery pressure (mPAP) and PVR, and 8% had >10 mmHg decline in mPAP to mPAP < 40 with normal cardiac output. Patients on riociguat had less response to O2 + iNO than patients on phosphodiesterase‐5 inhibitors. Our findings shed light on the significant variability in vascular tone that is present in CTEPH, confirming that CTEPH represents a combination of mechanical obstruction and vasoconstriction that appears similar to that observed with Group 1 PAH. Additional study regarding whether results of acute vasodilator testing predict response to therapy and relate to prognosis is warranted.