European Journal of Cardiovascular Medicine

Pulmonary hypertension (PH) is a heterogeneous and potentially life-threatening syndrome that complicates a wide range of cardiac, respiratory and systemic disorders. Its course can be indolent or rapidly progressive, and prognosis depends heavily on the underlying cause and on hemodynamic severity. For these reasons, modern management treats PH not as a single disease but as several distinct clinical entities grouped by etiology; this approach shapes diagnostic strategy, prognostic assessment and treatment choices.^[1]

Accurate hemodynamic assessment is central to that classification. Transthoracic echocardiography remains the primary screening test, but right-heart catheterization (RHC) is the diagnostic gold standard. RHC directly measures mean pulmonary arterial pressure, pulmonary arterial wedge pressure and cardiac output, and thereby permits calculation of pulmonary vascular resistance (PVR), measures needed to separate pre-capillary from post-capillary physiology and to guide therapy.^[2] Recent guideline updates have refined hemodynamic thresholds and emphasized the role of PVR when determining the presence of pulmonary vascular disease.^[3]

For patients with pulmonary arterial hypertension (WHO Group 1), targeted therapies that act on the nitric-oxide, endothelin and prostacyclin pathways have materially improved outcomes in selected populations. Contemporary guidelines therefore recommend a risk-stratified, targeted approach for those with confirmed pre-capillary disease. In routine practice, however, there is wide variability in the use of invasive haemodynamics, in access to disease-specific drugs, and in how care is organized, especially outside specialized referral centers.^[1,2]

The situation in many low- and middle-income settings reflects additional complexity. Regional registries and collaborative reports suggest that Group 2 PH (due to left-heart disease) commonly predominates, and that uptake of guideline-recommended PH agents is often lower than in high-resource registries. System-level barriers, variable physician familiarity with PH, constrained access to RHC, high out-of-pocket drug costs and fragmented referral pathways, further widen the gap between guidelines and real-world practice.^[4,5]

Against this backdrop, contemporary, descriptive cohort studies remain valuable. They document how patients are identified and treated in everyday practice, reveal gaps between recommendations and care, and help generate hypotheses for service development and prospective research. In this observational cohort we therefore set out to characterize the demographic profile, diagnostic testing (including RHC where available), patterns of PH-directed therapy and short-term outcomes in a consecutively recorded group of patients with PH.

Study Design and Setting

This is a retrospective, observational cohort study of consecutively recorded adults with pulmonary hypertension (PH) from a single-center registry.

Participants

Adults (≥18 years) with a registry diagnosis of PH and a unique patient identifier were eligible. Records missing a usable identifier or duplicate entries were excluded. The analytic sample comprised 61 patients.

Data Collection and Variables

Data were extracted from the registry into a structured dataset and de-identified before analysis. Extracted fields included demographics (age, sex, region, socioeconomic code), NYHA/WHO functional class, comorbidities (HTN, DM, IHD, RHD, CHD, COPD), smoking status, key investigations (TR velocity, echo-PASP, RV size, 6MWD, NT-proBNP), RHC flag and haemodynamics when available (mPAP, PCWP, PVR), WHO diagnostic group, PH-directed therapies (PDE-5 inhibitors, ERA, prostacyclin’s), anticoagulation, domiciliary oxygen, index and last-follow-up dates, and outcomes (alive at 90 days, alive at 1 year, heart-failure hospitalisation). Variables were coded as recorded (binary flags for comorbidities and therapies; categorical for WHO group and functional class).

Outcome Definitions

Primary descriptive outcomes were survival status at 90 days and 1 year and presence of heart-failure hospitalisation during follow-up. Invasive haemodynamic summaries are reported only for the subset with documented RHC.

Missing Data and Handling

Analyses used available-case denominators for each variable. No imputation was performed. Denominators are reported alongside results where relevant.

Statistical Analysis

Continuous variables are presented as mean ± SD when approximately symmetric or median (IQR) when skewed. Categorical variables are counts and percentages. Exploratory comparisons used chi-square or Fisher’s exact tests for categorical data and Welch’s t-test or Mann–Whitney U for continuous data as appropriate. Simple Kaplan–Meier curves were used for time-to-event summaries. A two-sided p < 0.05 was used as a conventional threshold; all inferential results are exploratory given sample size and study design. Analyses were performed using standard statistical software (Python or R); scripts are available on request.

Ethics

The study used de-identified, retrospective clinical data. Local institutional review board approval or waiver of informed consent was obtained as required. Data were handled according to institutional privacy policies

Study Sample and Flow

A total of 61 patients with pulmonary hypertension (PH) formed the analytic cohort (N = 61). All records meeting the inclusion definition in the source dataset were analyzed; no additional exclusions were applied for the analyses presented here.

Baseline Characteristics

The cohort had a mean age of 53.0 ± 14.4 years. Sex distribution was balanced: 30 males (49.2%) and 31 females (50.8%). Median six-minute walk distance (6MWD) was 370 m (IQR 315–437). Functional class by recorded NYHA/WHO field was predominantly class II–III (I = 5, II = 31, III = 16, IV = 9). Comorbid conditions were common: hypertension in 25 patients (41.0%), diabetes mellitus in 14 (23.0%), ischaemic heart disease in 24 (39.3%), rheumatic heart disease in 17 (27.9%) and congenital heart disease in 12 (19.7%). Chronic obstructive pulmonary disease and current smoking were present in 7 (11.5%) and 11 (18.0%), respectively.

Table 1 (below) summarizes key baseline demographics, functional class and comorbidities.

Etiology (WHO group) and Diagnostic Testing

WHO-group assignment from the dataset showed that the majority of patients were classified as Group 2 (pulmonary hypertension due to left heart disease). The distribution was:

1. WHO Group 1 (PAH): 14 (23.0%)
2. WHO Group 2 (PH-LHD): 34 (55.7%)
3. WHO Group 3 (PH due to lung disease / hypoxia): 9 (14.8%)
4. WHO Group 4 (CTEPH): 3 (4.9%)
5. WHO Group 5 (miscellaneous): 1 (1.6%)

This WHO-group distribution is summarized in Table 2 and depicted in Figure 1.

Right-heart catheterization (RHC) was recorded as performed in 11 of 61 patients (18.0%). Among patients with RHC data available, invasive haemodynamics indicated elevated pulmonary pressures and elevated pulmonary vascular resistance in many cases: median invasive mean pulmonary arterial pressure (mPAP) was ≈ 43.6 mmHg, and median pulmonary vascular resistance (PVR) was ≈ 10.57 Wood units (values calculated from the subset with RHC fields populated).

Figure 1. WHO-group distribution (bar chart; N = 61)

WHO diagnostic group distribution in the single-center cohort (N = 61). Bars show absolute counts; group labels indicate WHO group and common short name (PAH, PH-LHD, PH-lung, CTEPH, misc.).

PH-directed therapy and practice patterns

Overall, 28 of 61 patients (45.9%) were treated with at least one PH-specific targeted agent (PDE-5 inhibitor, ERA or prostacyclin analogue). Class-specific counts were:

1. PDE-5 inhibitors: 14/61 (23.0%)
2. Endothelin receptor antagonists (ERA): 14/61 (23.0%)
3. Prostacyclin analogues: 5/61 (8.2%)
4. Anticoagulation (TH_OAC): 7/61 (11.5%)
5. Oxygen therapy: 14/61 (23.0%)

Therapy uptake differed by WHO group (counts and proportions shown in Table 3 and Figure 3). Notably, a majority of Group 1 patients were receiving PH-targeted therapy, while fewer patients in Group 2 and Group 3 received disease-directed drugs.

1. Proportion on any PH-specific therapy by WHO group:
   • Group 1: 10/14 (71.4%)
   • Group 2: 14/34 (41.2%)
   • Group 3: 3/9 (33.3%)
   • Group 4: 1/3 (33.3%)
   • Group 5: 0/1 (0%)

Figure 2: Therapy-class distribution (donut chart)

Therapy-class distribution (class-level counts). Counts reflect the number of patients recorded as receiving each class (patients may be counted in >1 class). PDE-5 = phosphodiesterase-5 inhibitors; ERA = endothelin receptor antagonists.

Figure 3: PH-specific therapy uptake by WHO group (stacked bar chart)

PH-specific therapy uptake by WHO diagnostic group. Stacked bars show the number receiving at least one PH-specific targeted therapy (lower segment) and the number not receiving PH-specific therapy (upper segment). Numeric counts and group totals are annotated above bars.

Outcomes

Short-term survival in the cohort was high: 100% alive at 90 days (61/61). One-year survival recorded in the dataset was 56/61 (91.8%), corresponding to 5 deaths within 1 year. Heart-failure–related hospitalizations were common: 37/61 (60.7%) had at least one hospitalisation (dataset field HF_HOSP).

Outcomes stratified by therapy status or WHO group are available from the dataset and can be analyzed further on request (for example: 6MWD, NT-proBNP or hospitalization rates compared between those receiving PH-specific therapy vs not).

Additional descriptive observations

• Only 18% of patients had invasive haemodynamics recorded, highlighting limited RHC availability/documentation in this cohort. Where available, haemodynamics indicated significant pulmonary vascular disease (elevated mPAP and PVR).
• The majority etiologic category (WHO Group 2) and the high prevalence of structural heart disease (IHD, RHD, prior valve disease captured in comorbidity fields) suggest that left-heart disease is the dominant contributor in this dataset.
• Uptake of advanced therapies (ERAs and prostacyclin’s) was modest overall and concentrated among WHO Group 1 patients

In this single-centre registry cohort the dominant clinical pattern was pulmonary hypertension driven by left-heart disease (WHO Group 2), limited use of right-heart catheterisation, and selective use of pulmonary-vascular targeted therapy (concentrated in Group 1). These observations are consistent with contemporary guideline recommendations that emphasize careful phenotyping (including RHC when the result will change management) and a targeted-therapy approach principally for Group 1 pulmonary arterial hypertension (PAH).^[6]

The change in hemodynamic definitions and the renewed emphasis on precise invasive assessment in recent expert statements helps explain why registries and expert centers increasingly highlight gaps between ideal and real-world practice: invasive confirmation (mPAP, PVR, PCWP) remains the reference standard but is variably available in many settings.^[3]

Comparison with published registries and regional data

Large prospective registries from Europe and North America show higher rates of RHC and systematic risk-directed therapy than observed here. COMPERA and REVEAL report routine hemodynamic characterization and more widespread use of combination targeted therapy in contemporary PAH cohorts, with associated improvements in risk profile and longer-term outcomes.^[7,8] In contrast, data from Indian registry work (for example the PRO-KERALA registry and other regional series) describe a heavier case-mix of Group-2 disease, more frequent left-sided cardiac pathology, and practical barriers to widespread invasive assessment and advanced PH therapy in many centers. Those regional analyses similarly document delayed referral, limited access to some drug classes, and heterogenous follow-up, all factors that map onto our findings (high proportion Group 2, low RHC rate ~18%, targeted therapy concentrated in Group 1).^[4,9]

Interpretation of outcomes and Therapy Patterns

Short-term survival in our dataset was favorable (100% at 90 days; ~92% at 1 year). That pattern is compatible with registry reports which show that early survival in mixed PH cohorts can be relatively good, particularly when a large share of cases are Group 2 (where mortality trajectories differ from idiopathic PAH) and when follow-up is limited to 1 year. Larger registries also show that baseline functional class, 6-minute walk distance and biomarkers (NT-proBNP) predict outcomes and drive risk-guided escalation of therapy in PAH.^[8,10]

The relatively high rate of heart-failure hospitalisation (≈61%) in our sample is notable. It probably reflects the underlying prevalence of left-heart disease in the cohort and the limited use of invasive haemodynamics to separate isolated post-capillary PH from mixed pre-/post-capillary physiology, an important distinction because pulmonary vascular drugs have different roles and expected benefits in these contexts. The guidelines underscore that PH-targeted drugs are indicated mainly for Group 1 PAH or carefully selected Group 4/selected Group 3 situations after multidisciplinary evaluation and hemodynamic confirmation.^[6]

Practical Implications and Actionable Points

1. Improve access to haemodynamic testing where feasible. Right-heart catheterization clarifies hemodynamic phenotype (pre- vs post-capillary), quantifies PVR and informs therapy decisions; expanding access or referral pathways to centers that can perform RHC would reduce diagnostic uncertainty and avoid inappropriate or futile therapy._[3,6]
2. Prioritize guideline-directed therapy for confirmed PAH. Our data show that targeted agents are concentrated in Group 1; aligning local formularies, reimbursement policies and referral networks to guideline priorities will likely improve appropriate uptake for patients who will benefit most.^[6,7]
3. Focus on systems-level barriers. Registry and survey work from the region points to structural constraints, cost, drug availability, referral delays and variable follow-up, that limit implementation of guideline recommendations; addressing these (education, care pathways, pooled procurement or subsidized access programs) could materially change practice patterns.^[4,9]

Strengths and Limitations

Strengths: the dataset reflects consecutive, real-world registry entries and captures a broad case-mix of PH seen in routine practice. Limitations: retrospective registry data, modest sample size (N = 61), limited invasive haemodynamic data (RHC in 11 patients) and potential documentation/misclassification biases. Because of these constraints the findings are primarily descriptive and hypothesis-generating rather than definitive. The patterns we observe echo those reported in other regional series and emphasize the same structural issues identified by prior registry work.^[4,9]

Conclusion and Next Steps

This registry snapshot suggests that (a) left-heart disease is a dominant cause of PH in this cohort, (b) invasive haemodynamic assessment is underused relative to guideline ideals, and (c) targeted pulmonary vascular therapy is concentrated in established PAH cases. Aligning local practice with guideline-driven phenotyping, improving access to RHC and building sustainable pathways for evidence-based therapy (including multidisciplinary review and risk stratification) are logical next steps. Future prospective registry work with standardized RHC protocols, longer follow-up and linkage to outcome registries would help quantify the impact of such changes on morbidity and survival.^[6,7,9,10]

Most patients presented with mild–to moderate functional limitation (predominantly WHO/NYHA class II–III). Common comorbidities included systemic hypertension, diabetes and ischemic heart disease; right-heart catheterization (RHC) had been performed in a minority, and uptake of targeted PH therapies (PDE-5 inhibitors, ERAs, prostacyclin analogues) was suboptimal compared with guideline recommendations. Overall, the dataset mirrors patterns seen in regional and international registries, delayed invasive haemodynamic assessment, reliance on echocardiographic surrogates, and scope for improved implementation of risk-guided therapy and follow-up pathways to reduce heart-failure admissions and early mortality. These findings support the need for larger, prospective registry efforts with standardized RHC protocols and the systematic application of guideline-based risk stratification to guide treatment escalation

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