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.

Chronic thromboembolic pulmonary hypertension in Australia and New Zealand: An analysis of the PHSANZ registry.

BACKGROUND AND OBJECTIVE: Chronic thromboembolic pulmonary hypertension (CTEPH) is a serious condition occurring in 2%-4% of patients after acute pulmonary embolism. Pulmonary endarterectomy (PEA) is a potential cure for technically operable disease. The epidemiology and long-term outcomes of CTEPH have not been previously described in Australia and New Zealand. METHODS: Data were extracted from the Pulmonary Hypertension Society of Australia and New Zealand (PHSANZ) registry for patients diagnosed with CTEPH between January 2004 and March 2020. Baseline characteristics, treatment strategies, outcome data and long-term survival are reported. RESULTS: A total of 386 patients were included with 146 (37.8%) undergoing PEA and 240 (62.2%) in the non-PEA group. PEA patients were younger (55 ± 16 vs. 62 ± 16 years, p < 0.001) with higher baseline 6-min walk distance (6MWD; 405 ± 122 vs. 323 ± 146 m, p = 0.021), whilst both groups had similar baseline pulmonary haemodynamics. Pulmonary hypertension-specific therapy was used in 54% of patients post-PEA and 88% in the non-PEA group. The 1-, 3- and 5-year survival rates were 93%, 87% and 84% for the PEA group compared to 86%, 73% and 62%, respectively, for the non-PEA group (p < 0.001). Multivariate survival analysis showed baseline 6MWD was an independent predictor of survival in both operated and medically managed patients. CONCLUSION: In this first multicentre report of CTEPH in Australia and New Zealand, long-term survival is comparable to that in other contemporary CTEPH registries. However, PEA was only performed in a minority of CTEPH patients (37.8%) and significantly less than overseas reports. Greater awareness of PEA and improved patient access to experienced CTEPH centres are important priorities.

Pulmonary arterial hypertension with below threshold pulmonary vascular resistance.

Pulmonary vascular resistance (PVR) >3 Wood units is a criterion of the haemodynamic definition of pulmonary arterial hypertension (PAH). However, this cut-off is conservative and arbitrarily defined. Data is lacking on the natural history, response to therapy and survival of patients diagnosed with precapillary pulmonary hypertension (PH) with mild or borderline elevation of PVR.In Australia, PAH therapy could be prescribed solely on mean pulmonary arterial pressure (PAP) and pulmonary arterial wedge pressure (PAWP) criteria. Using the Australian and New Zealand Pulmonary Hypertension Registry, we aimed to study a population diagnosed with PAH between January 2004 and December 2017 with the pre-defined haemodynamic characteristics of mean PAP ≥25 mmHg, PAWP ≤15 mmHg and PVR <3 Wood units.Eighty-two patients met the pre-defined haemodynamic inclusion criteria (mean age 63±11 years; 67 females). Underlying aetiologies included idiopathic disease (n=39), connective tissue disease (CTD; n=42) and HIV infection (n=1). At diagnosis, mean PAP was 27 mmHg (interquartile range (IQR) 25-30 mmHg), PAWP 13 mmHg (IQR 11-14 mmHg) and PVR 2.2 Wood units (IQR 1.9-2.7 Wood units). Baseline 6-min walk distance (6MWD) was 352 m (IQR 280-416 m) and 77% of subjects were in New York Heart Association (NYHA) functional class 3 or 4. All patients were commenced on initial monotherapy with an endothelin receptor antagonist (ERA; n=66) or phosphodiesterase type-5 inhibitor (PDE5i; n=16). At first re-evaluation, 6MWD increased by 46 m (IQR 7-96 m) and 35% of subjects demonstrated improvement in NYHA functional class. After a median follow-up of 65 months (IQR 32-101 months), 18 out of 82 subjects (22.0%) had died, with estimated 1-year and 5-year survival rates of 98% and 84%, respectively. Death attributed to PAH occurred in six out of these 18 patients (33.3%, 7% of total cohort).Patients with precapillary PH and "borderline" PVR falling outside the current definition have adverse outcomes. Such patients appear to respond to PAH therapy; however, this requires further study in randomised trials.

Diagnostic delay in pulmonary arterial hypertension: Insights from the Australian and New Zealand pulmonary hypertension registry.

BACKGROUND AND OBJECTIVE: Early diagnosis of PAH is clinically challenging. Patterns of diagnostic delay in Australian and New Zealand PAH populations have not been explored in large-scale studies. We aimed to evaluate the magnitude, risk factors and survival impact of diagnostic delay in Australian and New Zealand PAH patients. METHODS: A cohort study of PAH patients from the PHSANZ Registry diagnosed from 2004 to 2017 was performed. Diagnostic interval was the time from symptom onset to diagnostic right heart catheterization as recorded in the registry. Factors associated with diagnostic delay were analysed in a multivariate logistic regression model. Survival rates were compared across patients based on the time to diagnosis using Kaplan-Meier method and Cox regression. RESULTS: A total of 2044 patients were included in analysis. At diagnosis, median age was 58 years (IQR: 43-69), female-to-male ratio was 2.8:1 and majority of patients were in NYHA FC III-IV (82%). Median diagnostic interval was 1.2 years (IQR: 0.6-2.7). Age, CHD-PAH, obstructive sleep apnoea and peripheral vascular disease were independently associated with diagnostic interval of ≥1 year. No improvement in diagnostic interval was seen during the study period. Longer diagnostic interval was associated with decreased 5-year survival. CONCLUSION: PAH patients experience significant diagnostic interval, which has not improved despite increased community awareness. Age, cardiovascular and respiratory comorbidities are significantly associated with longer time to diagnosis. Mortality rates appear higher in patients who experience longer diagnostic interval.

Survival of Idiopathic Pulmonary Arterial Hypertension Patients in the Modern Era in Australia and New Zealand.

BACKGROUND: Epidemiology and treatment strategies continue to evolve in pulmonary arterial hypertension (PAH). We sought to define the characteristics and survival of patients with idiopathic, heritable and drug-induced PAH in the current management era. METHODS: Consecutive cases of idiopathic, heritable and drug-induced PAH were prospectively enrolled into an Australian and New Zealand Registry. RESULTS: Between January 2012 and December 2016, a total of 220 incident cases were enrolled (mean age 57.2±18.7years, female 69.5%) and followed for a median duration of 26 months (IQR17-39). Co-morbidities were common such as obesity (34.1%), systemic hypertension (30.5%), coronary artery disease (16.4%) and diabetes mellitus (19.5%). Initial combination therapy was used in 54 patients (dual, n=50; triple, n=4). Estimated survival rates at 1-year, 2-years and 3-years were 95.6% (CI 92.8-98.5%), 87.3% (CI 82.5-92.4%) and 77.0% (CI 70.3-84.3%), respectively. Multivariate analysis showed that male sex and lower 6-minute distance at diagnosis independently predicted worse survival, whereas obesity was associated with improved survival. Co-morbidities other than obesity did not impact survival. Initial dual oral combination therapy was associated with a trend towards better survival compared with initial oral monotherapy (adjusted HR=0.27, CI 0.06-1.18, p=0.082) CONCLUSIONS: The epidemiology and survival of patients with idiopathic PAH in Australia and New Zealand are similar to contemporary registries reported in Europe and North America. Male sex and poorer exercise capacity are predictive of mortality whereas obesity appears to exert a protective effect. Despite current therapies, PAH remains a life-threatening disease associated with significant early mortality.

Impact of Left Heart Disease Risk Factors on Outcomes in Pulmonary Arterial Hypertension Therapy.

BACKGROUND: Current guidelines recommend initial monotherapy for pulmonary arterial hypertension (PAH) with cardiopulmonary comorbidities, despite limited available evidence to guide management. RESEARCH QUESTION: Do left heart disease (LHD) risk factors have an impact on treatment response and influence applicability of risk assessment in a real-world cohort of patients with PAH? STUDY DESIGN AND METHODS: The Ambrisentan and Tadalafil in Patients with Pulmonary Arterial Hypertension (AMBITION) trial criteria was used to define the phenotype of patients with PAH with risk factors for LHD. Treatment strategy, functional outcome, long-term survival, and risk discrimination were compared with a reference PAH cohort using the Pulmonary Hypertension Society of Australia and New Zealand Registry. RESULTS: A total of 487 incident patients with PAH diagnosed between 2011 and 2020 were included. Of these, 103 (21.1%) fulfilled the definition of PAH with LHD risk factors, with 384 (78.9%) remaining as the reference group. Patients in the PAH with LHD risk factors group were older (66 ± 13 vs 58 ± 19 years; P < .001), had lower pulmonary vascular resistance (393 ± 266 vs 708 ± 391 dyn.s/cm5; P = .031), and had worse 6-min walk distance (286 ± 130 vs 327 ± 136 m; P = .005) at diagnosis. The PAH with LHD risk factors group was less likely to receive initial combination therapy (27% vs 44%; P = .02). Changes in 6-min walk distance at 12 months were similar in both groups (43 ± 77 m in the PAH with LHD risk factors group and 50 ± 90 m in the reference group; P = .50), including when stratified by initial treatment strategy (PAH with LHD risk factors group vs reference PAH group: monotherapy: 40 ± 81 vs 38 ± 95 m, P = .87; combination therapy: 53 ± 78 vs 64 ± 106 m, P = .511). Functional class improvements were also similar in both groups. REVEAL Registry 2.0 risk score effectively discriminated risk in both populations (C statistic = 0.756 for the PAH with LHD risk factors group and C statistic = 0.750 for the reference PAH group). There was no difference in survival between the two groups (log-rank test, P = .29). INTERPRETATION: In a real-world cohort, patients with PAH with LHD risk factors were less likely to be exposed to initial combination therapy. Nevertheless, selected patients with PAH with LHD risk factors who were treated with initial combination therapy derived similar functional response compared with the reference group. Further studies are needed to phenotype patients with PAH with cardiopulmonary comorbidities who may benefit from initial combination therapy.

A prospective trial assessing the safety and efficacy of collecting up to 840 mL of plasma in conjunction with saline infusion during plasmapheresis.

BACKGROUND: The demand for plasma for manufacturing intravenous immunoglobulin and other plasma derivatives is increasing. A prospective study was conducted to determine whether up to 840 mL of plasma could be safely and effectively collected in conjunction with saline infusion during plasmapheresis. STUDY DESIGN AND METHODS: Ninety-one plasma donors were enrolled in a modified 3 × 3 crossover study to assess the equivalence of three plasma collection methods: 750 mL of plasma with no saline (control, Method 1), 840 mL of plasma with a 250-mL saline infusion during and at the end of the donation (Method 2), and 800 mL of plasma with a 500-mL saline infusion at the end of the donation (Method 3). The primary efficacy endpoint was the total protein concentration of the collected plasma. Secondary efficacy endpoints were immunoglobulin (Ig)G and Factor (F)VIII plasma concentration and donors' acceptance of the new procedures. Safety was determined from the adverse event (AE) rate. RESULTS: The total protein, IgG, and FVIII concentrations in plasma collected under Methods 2 and 3 were significantly lower than those in plasma collected under Method 1 (p < 0.0001). These variables were also significantly lower in plasma collected under Method 2 compared to Method 3. During the study, 75 AEs were recorded, 73 of which were mild to moderate. Significantly more donors (31%) preferred Method 2 compared to Method 3 (p = 0.006). CONCLUSIONS: Saline infusion during plasmapheresis led to hemodilution of plasma proteins. However, the benefits to donor safety and satisfaction are compelling reasons to implement saline infusion during plasmapheresis.

Retrospective Validation of the REVEAL 2.0 Risk Score With the Australian and New Zealand Pulmonary Hypertension Registry Cohort.

BACKGROUND: Pulmonary arterial hypertension (PAH) prognosis has improved with targeted therapies; however, the long-term outlook remains poor. Objective multiparametric risk assessment is recommended to identify patients at risk of early morbidity and mortality, and for optimization of treatment. The US Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL) 2.0 risk score is a new model proposed for the follow-up of patients with PAH but has not been externally validated. METHODS: The REVEAL 2.0 risk score was applied to a mixed prevalent and incident cohort of patients with PAH (n = 1,011) from the Pulmonary Hypertension Society of Australia and New Zealand (PHSANZ) Registry. Kaplan-Meier survival was estimated for each REVEAL 2.0 risk score strata and for a simplified three-category (low, intermediate, and high risk) model. Sensitivity analysis was performed on an incident-only cohort. RESULTS: The REVEAL 2.0 model effectively discriminated risk in the large external PHSANZ Registry cohort, with a C statistic of 0.74 (both for full eight-tier and three-category models). When applied to incident cases only, the C statistic was 0.73. The three-category REVEAL 2.0 model demonstrated robust separation of 12- and 60-month survival estimates (all risk category comparisons P < .001). Although the full eight-tier REVEAL 2.0 model separated patients at low, intermediate, and high risk, survival estimates overlapped within some of the intermediate- and high-risk strata. CONCLUSIONS: The REVEAL 2.0 risk score was validated in a large external cohort from the PHSANZ Registry. The REVEAL 2.0 model can be applied for risk assessment of patients with PAH at follow-up. The simplified three-category model may be preferred for clinical use and for future comparison with other prognostic models.