Pulmonary hypertension (PH) is hemodynamically classified as pre-capillary (as seen in idiopathic pulmonary arterial hypertension [IPAH]) or post-capillary (as seen in heart failure with preserved ejection fraction [HFpEF]). Overlaps between these conditions exist. Some patients present with risk factors for left heart disease but pre-capillary PH, whereas patients with HFpEF may have combined pre- and post-capillary PH. This study sought to further characterize similarities and differences among patient populations with either PH-HFpEF or IPAH. We used registry data to analyze clinical characteristics, hemodynamics, and treatment responses in patients with typical IPAH (<3 risk factors for left heart disease; n = 421), atypical IPAH (≥3 risk factors for left heart disease; n = 139), and PH-HFpEF (n = 226) receiving PH-targeted therapy. Compared with typical IPAH, patients with atypical IPAH and PH-HFpEF were older, had a higher body mass index, had more comorbidities, and had a lower 6-min walking distance, whereas mean pulmonary artery pressure (46.9 ± 13.3 mm Hg vs. 43.9 ± 10.7 mm Hg vs. 45.7 ± 9.4 mm Hg, respectively) and cardiac index (2.3 ± 0.8 l/min/m(2) vs. 2.2 ± 0.8 l/min/m(2) vs. 2.2 ± 0.7 l/min/m(2), respectively) were comparable among groups. After initiation of targeted PH therapies, all groups showed improvement in exercise capacity, functional class, and natriuretic peptides from baseline to 12 months, but treatment effects were less pronounced in patients with PH-HFpEF than typical IPAH; with atypical IPAH in between. Survival rates at 1, 3, and 5 years were almost identical for the 3 groups. Patients with atypical IPAH share features of both typical IPAH and PH-HFpEF, suggesting that there may be a continuum between these conditions.

Pulmonary arterial hypertension (PAH) is a common complication of congenital heart disease (CHD), with most cases occurring in patients with congenital cardiac shunts. In patients with an uncorrected left-to-right shunt, increased pulmonary pressure leads to vascular remodelling and dysfunction, resulting in a progressive rise in pulmonary vascular resistance and increased pressures in the right heart. Eventually, reversal of the shunt may arise, with the development of Eisenmenger's syndrome, the most advanced form of PAH-CHD.The prevalence of PAH-CHD has fallen in developed countries over recent years and the number of patients surviving into adulthood has increased markedly. Today, the majority of PAH-CHD patients seen in clinical practice are adults, and many of these individuals have complex disease or received a late diagnosis of their defect. While there have been advances in the management and therapy in recent years, PAH-CHD is a heterogeneous condition and some subgroups, such as those with Down's syndrome, present particular challenges.This article gives an overview of the demographics, pathophysiology and treatment of PAH-CHD and focuses on individuals with Down's syndrome as an important and challenging patient group.

Exercise stress tests have been used for the diagnosis of pulmonary hypertension, but with variable protocols and uncertain limits of normal.The pulmonary haemodynamic response to progressively increased workload and recovery was investigated by Doppler echocardiography in 25 healthy volunteers aged 19–62 yrs (mean 36 yrs). Mean pulmonary artery pressure (P̄_pa) was estimated from the maximum velocity of tricuspid regurgitation. Cardiac output (Q) was calculated from the aortic velocity-time integral. Slopes and extrapolated pressure intercepts ofP̄_pa–Q plots were calculated after using the adjustment of Poon for individual variability. A pulmonary vascular distensibility α was calculated from eachP̄_pa–Q plot to estimate compliance.P̄_paincreased from 14±3 mmHg to 30±7 mmHg, and decreased to 19±4 mmHg after 5 min recovery. The slope ofP̄_pa–Q was 1.37±0.65 mmHg·min⁻¹·L⁻¹with an extrapolated pressure intercept of 8.2±3.6 mmHg and an α of 0.017±0.018 mmHg⁻¹. These results agree with those of previous invasive studies. MultipointP̄_pa–Q plots were well described by a linear approximation, from which resistance can be calulated.We conclude that exercise echocardiography of the pulmonary circulation is feasible and provides realistic resistance and compliance estimations. Measurements during recovery are unreliable because of rapid return to baseline.