Positive Vasoreactivity Testing in Pulmonary Arterial Hypertension: Therapeutic Consequences, Treatment Patterns, and Outcomes in the Modern Management Era.

BACKGROUND: Among patients with pulmonary arterial hypertension (PAH), acute vasoreactivity testing during right heart catheterization may identify acute vasoresponders, for whom treatment with high-dose calcium channel blockers (CCBs) is recommended. However, long-term outcomes in the current era remain largely unknown. We sought to evaluate the implications of acute vasoreactivity response for long-term response to CCBs and other outcomes. METHODS: Patients diagnosed with PAH between January 1999 and December 2018 at 15 pulmonary hypertension centers were included and analyzed retrospectively. In accordance with current guidelines, acute vasoreactivity response was defined by a decrease of mean pulmonary artery pressure by ≥10 mm Hg to reach <40 mm Hg, without a decrease in cardiac output. Long-term response to CCBs was defined as alive with unchanged initial CCB therapy with or without other initial PAH therapy and World Health Organization functional class I/II and/or low European Society of Cardiology/European Respiratory Society risk status at 12 months after initiation of CCBs. Patients were followed for up to 5 years; clinical measures, outcome, and subsequent treatment patterns were captured. RESULTS: Of 3702 patients undergoing right heart catheterization for PAH diagnosis, 2051 had idiopathic, heritable, or drug-induced PAH, of whom 1904 (92.8%) underwent acute vasoreactivity testing. A total of 162 patients fulfilled acute vasoreactivity response criteria and received an initial CCB alone (n=123) or in combination with another PAH therapy (n=39). The median follow-up time was 60.0 months (interquartile range, 30.8-60.0), during which overall survival was 86.7%. At 12 months, 53.2% remained on CCB monotherapy, 14.7% on initial CCB plus another initial PAH therapy, and the remaining patients had the CCB withdrawn and/or PAH therapy added. CCB long-term response was found in 54.3% of patients. Five-year survival was 98.5% in long-term responders versus 73.0% in nonresponders. In addition to established vasodilator responder criteria, pulmonary artery compliance at acute vasoreactivity testing, low risk status and NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels at early follow-up correlated with long-term response and predicted survival. CONCLUSIONS: Our data display heterogeneity within the group of vasoresponders, with a large subset failing to show a sustained satisfactory clinical response to CCBs. This highlights the necessity for comprehensive reassessment during early follow-up. The use of pulmonary artery compliance in addition to current measures may better identify those likely to have a good long-term response.

Ferric carboxymaltose in patients with pulmonary arterial hypertension and iron deficiency: a long-term study.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a progressive disease with limited survival. Iron deficiency (ID) correlates with disease severity and mortality. While oral iron supplementation was shown to be insufficient in such patients, the potential impact of parenteral iron on clinical measures warrants further investigation. METHODS: We retrospectively analysed the long-term effects of intravenous ferric carboxymaltose (FCM) on iron status and clinical measures in patients with PAH and ID [ferritin < 100 µg/L or ferritin 100-300 µg/L and transferrin saturation (TSAT) < 20%] who were on stable targeted PAH therapy, compared with matched controls without ID. Patients with ID received a single infusion of FCM (500 to 1000 mg). Clinical measures monitored included exercise capacity, World Health Organization (WHO) functional class, ESC/ERS risk status, and hospitalizations. The observation period was up to 18 months. RESULTS: One hundred and seventeen patients (mean age 60.9 ± 16.1 years; 64.1% females) with confirmed PAH and on stable targeted therapy for ≥3 months were included (58 with and 59 patients without ID who did not receive FCM). In patients with ID, iron supplementation with FCM resulted in an immediate and sustained improvement of iron status for up to 18 months (serum iron, ferritin, TSAT, all P < 0.01). Fourteen patients in the FCM group received a second FCM infusion after 9.6 ± 4.8 months due to recurrent ID. At 6 and 18 months after FCM infusion, 6 min walk distance improved from 377.5 ± 15.9 at baseline to 412.5 ± 15.1 and 400.8 ± 14.5 m, respectively (both P < 0.05). WHO functional class (P < 0.05) and ESC/ERS risk status also improved, and there was a reduction of hospitalizations for worsening PAH in the 12 months post vs. prior to iron repletion (P = 0.029). No significant changes were observed in the control group. FCM was well tolerated in all patients, with no severe adverse events. CONCLUSIONS: In addition to targeted therapy, correction of ID by parenteral iron supplementation with FCM appears feasible and safe, has sustained effects on iron status, and may improve the clinical status and hospitalization rates in patients with PAH. Larger controlled studies are required to confirm this finding.

Ferric carboxymaltose improves exercise capacity and quality of life in patients with pulmonary arterial hypertension and iron deficiency: a pilot study.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a progressive condition harboring a poor prognosis. Iron deficiency in PAH correlates with disease severity and mortality. While replacement therapy may be beneficial, dietary iron absorption is impaired in PAH patients by hepcidin, a key regulatory protein of iron homoeostasis. We therefore assessed the therapeutic potential and safety of intravenous iron supplementation in patients with PAH and iron deficiency. METHODS: 20 patients with PAH and iron deficiency, who were on stable targeted PAH therapy, received a single infusion of ≤1000 mg ferric carboxymaltose. All patients were assessed at baseline and two months after iron treatment. Exercise capacity was evaluated based on the 6-minute-walking distance (6MWD), and quality of life (QoL) was assessed by the SF-36 questionnaire (100 point scale). The effects were compared to 20 matched patients with stable PAH without iron deficiency who did not receive ferric carboxymaltose. RESULTS: In iron deficient patients, iron supplementation led to a marked improvement of iron status (serum iron 5.7±0.4 to 11.1±1.1 µmol/L, ferritin 29.3±6.3 to 145.2±25.4 µg/L, transferrin saturation 7.5±0.7 to 19.3±2.3%, all p≤0.001). Iron-deficient patients receiving ferric carboxymaltose showed a significant increase of the 6MWD from 346.5±28.3 to 374.0±25.5 m (p=0.007), whereas no significant changes were found in the control group not receiving iron supplementation (6MWD 389.9±25.3 to 379.6±26.2 m; n.s.), resulting in a net increase in the 6MWD of 37.8m (p=0.003). This was associated with an improvement in QoL (SF-36 score from 44.3±3.7 to 50.6±3.6; p=0.01). Only minimal side-effects were reported. CONCLUSIONS: These data indicate that parenteral iron supplementation with ferric carboxymaltose significantly improves exercise capacity and QoL and is well tolerated in patients with PAH and iron deficiency, and when administered in addition to targeted PAH therapies. Our results provide proof of concept for further studies evaluating the potential of iron as an adjunct in PAH treatment on a larger scale.