Unveiling orthostatic hypotension in precapillary pulmonary hypertension
Bibliographic record
Abstract
Background In addition to critical alterations in the pulmonary arterial network, pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) may exhibit cardiovascular abnormalities that impair systemic arterial pressure regulation during gravitational challenges. Therefore, we investigated the prevalence, subtypes and haemodynamic mechanisms of orthostatic hypotension (OH) in PAH or CTEPH. Methods OH was assessed using a 10-min active standing manoeuvre from supine baseline, with heart rate (HR; ECG) and arterial pressure (volume-clamp finger photoplethysmography) measured beat by beat. Stroke volume (SV) was estimated from the arterial pressure waveform, and cardiac output (CO) and total peripheral resistance (TPR) were calculated. Results Among 60 patients, 31 (52%) had OH. Patients with and without OH did not differ in clinical characteristics and OH related symptoms (all p>0.050). HR, SV, CO and TPR responses (% change from supine baseline) were not different between groups with and without initial OH (p>0.05). However, SV decrease was greater in the group with than without delayed arterial pressure recovery (−31±21 versus −19±14%; p=0.033). Additionally, a compensatory increase in TPR was blunted in the group with classic/delayed OH compared with without OH (−6±21 versus 7±15%; p=0.023). Conclusion OH is common in patients with PAH or CTEPH but is not associated with specific clinical characteristics. Initial OH lacks a clear haemodynamic cause, whereas delayed recovery and classic/delayed OH are linked to impaired SV and TPR responses to standing, respectively.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".