Effect of calcium channel blockers evaluated by cardiopulmonary exercise testing in idiopathic pulmonary arterial hypertension responding to acute pulmonary vasoreactivity testing

BACKGROUND

The baseline exercise capacity evaluated by cardiopulmonary exercise testing (CPET) and the change after administration of calcium channel blockers (CCB) therapy in patients with vasodilator-responsive idiopathic pulmonary arterial hypertension (VR-IPAH)are unknown.

METHODS

25 patients with newly diagnosed VR-IPAH from 1 January 2012 to 16 November 2015 were prospectively enrolled, and 28 age, sex and pulmonary vascular resistance matched newly diagnosed patients with vasodilator-nonresponsive idiopathic pulmonary arterial hypertension (VNR-IPAH) were enrolled. CPET was performed before and after 3.5 ± 0.8 months of CCB or sildenafil therapy.

RESULTS

Ventilatory efficiency at rest, anaerobic threshold (AT), and peak were significantly higher (lower in V˙E/V˙CO₂@AT and higher in PETCO₂@AT) in VR-IPAH group than that in VNR-IPAH group. Peak V˙O₂ (13.9 ± 2.9 mL kg^-1·min^-1 vs 16.4 ± 4.1 mL kg^-1·min^-1, p = 0.001), peak O₂ pulse (5.5 ± 0.8 mL min^-1·beat^-1 vs 6.9 ± 1.3 mL min^-1·beat^-1, p = 0.001), V˙E/V˙CO₂@AT (34.2 ± 5.0 vs 31.6 ± 3.1, p = 0.02) and PETCO₂@AT (33.1 ± 4.0 mmHg vs 35.3 ± 3.2 mmHg, p = 0.02) were significantly improved after high dose of CCB therapy, along with improvement of WHO functional class, 6-min walking distance, NT-proBNP and tricuspid regurgitation pressure gradient.

CONCLUSIONS

Ventilatory efficiency in patients with VR-IPAH is better than that in patients with VNR-IPAH. CCB can improve aerobic capacity and ventilatory efficiency during exercise in patients with VR-IPAH.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov:NCT02061787.

Acute Vasoreactivity Testing and Outcomes in Pulmonary Arterial Hypertension: A Call for Increased Testing

BACKGROUND

Pulmonary arterial hypertension (PAH) has a progressive, unremitting clinical course. Vasoreactivity testing (VdT) during right heart catheterisation (RHC) identifies a subgroup with excellent long-term response to calcium channel blockade (CCB). Reporting on these patients is limited. Established in 2011, the Pulmonary Hypertension Society of Australia and New Zealand (PHSANZ) registry offers the opportunity to assess the frequency of VdT during RHC, treatment and follow up of PAH patients.

METHODS

Registry data from 3,972 PAH patients with index RHC revealed 1,194 VdT appropriate patients. Data was analysed in three groups: 1) VdT+CCB+: VdT positive, CCB treated; 2) VdT+CCB-: VdT positive, no CCB prescribed, 3) VdT-/noVdT: VdT negative, or VdT not tested. Data was reviewed for adherence to guidelines, clinical response (World Health Organization functional class [WHO FC], 6-minute-walk-distance [6MWD], RHC), and outcomes (survival or lung transplantation).

RESULTS

Patients included had idiopathic (IPAH=1,087), heritable (HPAH=67) and drug or toxin-induced PAH (DPAH=40). A VdT was performed in 22% (268/1,194), with incomplete data in 26% (70/268); 28% (55/198) were VdT+. Analysis group allocation was: VdT+CCB+ (33/55), VdT+CCB- (22/55), VdT- (143)/noVdT (996). From patients with 1-year data VdT+CCB+ and VdT-/noVdT patients improved WHO FC, 6MWD and cardiac index (CI); VdT+CCB- data remained similar. Within the VdT+CCB+ group, 30% (10/33) were long-term CCB responders with a 100% 5-year survival; non-responders had a 61% survival at 5.4 years. Long-term responders were younger at diagnosis (40 yrs vs 54 yrs).

CONCLUSION

Use of VdT testing and documentation is poor in this contemporary patient cohort. Nonetheless, survival in VdT+CCB+ patients from the PHSANZ registry is excellent, supporting guidelines promoting VdT testing. Strategies to promote the use of VdT are warranted.

Self-reported physician practices in pulmonary arterial hypertension: Diagnosis, assessment, and referral

Background

Numerous clinical trials have contributed to rapid advancements in the diagnosis and management of pulmonary arterial hypertension (PAH), yet patients often do not undergo right heart catheterization (RHC) with vasoreactivity testing and may receive a delayed or incorrect diagnosis. Efforts to improve standards of care include the designation of Pulmonary Hypertension Association (PHA)-Accredited PH Care Centers (PHCCs). This study evaluated current practices in the diagnosis and assessment of PAH.

Methods

A survey of 167 physicians who had ≥1 claim for PAH in the past 3 months was conducted.

Results

Of 167 respondents, 15% were affiliated with a PHCC, 40% had referred ≥1 patient with diagnosed PAH, and 79% had ≥1 patient referred to them by another physician who they then newly diagnosed with PAH. More than half (52%) reported having ≥1 patient who was previously misdiagnosed with PAH referred to them by another physician. RHC and vasoreactivity testing, respectively, were performed in 43% and 33% of patients with PAH who respondents referred to another physician, 86% and 67% of patients newly diagnosed by respondents, and 84% and 57% of patients who respondents considered accurately diagnosed prior to being referred to them. Respondents affiliated with a PHCC were more likely to try to refer to another physician affiliated with a PHCC, and to perform RHC and vasoreactivity testing.

Conclusions

Self-reported clinical practices often deviated from established guidelines. Future research should focus on both clinical efficacy and ways to encourage clinicians to bring their practices in line with well-supported, evidence-based recommendations.

What is the meaning of provoked spasm phenotypes by vasoreactivity testing?

Coronary artery epicardial spasm is involved in the pathogenesis of many cardiac disorders. Vasoreactivity testing, such as intracoronary injection of acetylcholine (ACH) or ergonovine (ER), is the gold standard method for the diagnosis of vasospastic angina. Provoked epicardial spasm phenotypes are classified as focal spasm and diffuse spasm. Multiple factors, including sex, ethnicity, and use of coronary vasoactive stimulators, are related to the provoked phenotypes of epicardial spasm. Diffuse-provoked spasm is often observed in females, where focal-provoked spasm is markedly more common in males. ACH provokes more diffuse and distal spasms, whereas ER induces more focal and proximal spasms. Yellow plaque and coronary thrombi are often observed in lesions with focal spasms, and intimal thickness with a sonolucent zone is significantly more common in lesions with focal spasm. Furthermore, clinical outcomes in patients with focal spasm are unsatisfactory compared with those in patients with diffuse spasm. However, the reproducibility and eternality of provoked spasm phenotypes by vasoreactivity testing is uncertain. Coronary atherosclerosis or endothelial damage may affect coronary vasomotor tone. Although coronary artery spasm may persist in the same coronary artery, provoked coronary spasm phenotypes may exhibit a momentary coronary reaction by intracoronary ACH or ER testing.

Evaluation of the acute effects of inhaled iloprost on aortic compliance in pulmonary arterial hypertension using invasive methods

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterized by vascular remodeling and elevated pulmonary vascular resistance. Aortic compliance indicates vascular stiffness and may be increased in PAH. Inhaled iloprost, a prostacyclin analog, is commonly used for PAH treatment and vasoreactivity testing. Its acute effects on aortic compliance remain unclear. This study evaluated the immediate impact of inhaled iloprost on aortic compliance through aortic pulse wave velocity (aPWV) measurements and pressure parameters in patients with PAH undergoing right heart catheterization.

METHODS

This single-center, cross-sectional study enrolled patients with group 1 PAH who underwent right heart catheterization with pulmonary vasoreactivity testing between August 2022 and May 2023. Aortic compliance was measured via aPWV before and after inhaling 20 mcg/mL iloprost. On the basis of the post-iloprost changes, 32 patients were categorized into high-aPWV (n = 4) or low-aPWV (n = 28) groups. Multivariate regression analysis identified significant predictors of impaired aortic stiffness.

RESULTS

The median patient age was 54.5 years (42.2-60.5). No significant differences were found between groups regarding percentage reductions in proximal/distal aortic pressure and pulmonary artery pressure after iloprost administration. The QRS interval was a significant predictor of impaired aortic stiffness (odds ratio: 1.072, 95% confidence interval: 1.002-1.197, p = 0.045). The high-aPWV group demonstrated significantly lower QRS intervals compared to the low-aPWV group (79.0 ms [70.5-84.0] vs. 96.0 ms [85.5-102.0], p = 0.011).

CONCLUSIONS

Inhaled iloprost effectively reduced both aortic pressure and pulmonary artery pressure regardless of aortic compliance in patients with group 1 PAH. The QRS interval emerged as an independent predictor of impaired aortic stiffness, offering potential for risk stratification in clinical practice.

The Need for Separate Testing with Acetylcholine for the Assessment of Endothelial Dysfunction and Coronary Artery Spasm

Intracoronary acetylcholine (ACH) testing is clinically useful to diagnose the presence of the coronary vasomotor disorders coronary endothelial dysfunction and coronary epicardial/microvascular spasm. In Western countries, continuous intracoronary injection of ACH for 2-3 minutes without a pacemaker is the usual method, while rapid injection of ACH for 20-30 seconds with a pacemaker is the traditional procedure in Japan. Coronary microvascular spasm is often observed in Western populations, whereas coronary epicardial spasm is frequently seen in Japanese subjects. Methodological differences between Western and Japanese protocols may lead to the opposite prevalence of coronary vasomotor disorders. This article discusses the optimal method for diagnosing endothelial dysfunction and epicardial/microvascular spasm based on previous reports, and compares intracoronary ACH testing performed by Western cardiologists with that by Japanese physicians.