Intraventricular Pressure Difference by Blood Speckle Tracking - Invasive Validation and Clinical Application
Bibliographic record
Abstract
Abstract Background Early diastolic relaxation creates an intraventricular pressure difference (IVPD) and resulting diastolic suction. Non-invasive estimation by echocardiographic techniques would allow to clinically evaluate this IVPD as an important component of ventricular filling. Recently, Blood Speckle Tracking (BST) echocardiography was introduced, allowing two-dimensional assessment of ventricular flow dynamics. Mitral inflow BST data can be used to estimate IVPD. The aims of the current study were to evaluate the accuracy of BST-based IVPD estimation compared to invasive pressure measurements in an in vivo animal model, and to clinically apply the method by comparing IVPD in children with univentricular hearts (UVH) and healthy controls. Methods The accuracy of BST-based IVPD-estimates was assessed in an open-chest porcine model, comparing BST-based IVPD with simultaneous repeated invasive pressure measurements in six pigs using micromanometer catheters. BST-based IVPD assessment was performed in 120 healthy controls and 44 patients with UVH < 18 years of age. Total IVPD (from base to apex) and apical IVPD (from the apical 2/3 of the ventricle) during early diastolic filling of the systemic ventricle was compared between patients with UVH and healthy controls. Results The validation in pigs included 103 measurements, demonstrating a mean difference of - 0.01mmHg (p=0.33) and high correlation (r = 0.95, p-value < 0.001) between IVPD from BST (-1.31 ± 0.28 mmHg) and invasive measurements (-1.30 ± 0.31 mmHg). In the pediatric patients, age range 2 days-17.76 years, feasibility was 96% in controls and 88.6% in UVH patients. Total and apical IVPD were significantly higher in controls compared to UVH (-1.82 vs -0.88 mmHg and -0.63 vs -0.33 mmHg, p < 0.001). Variability was low with intraclass correlation coefficients of 0.99/0.96 (interobserver) and 0.98/0.99 (intraobserver) for total and apical IVPD respectively. Conclusions BST echocardiography provides accurate estimation of early diastolic IVPD. When clinically applied in children, we found high feasibility and reproducibility. IVPD was significantly lower in children with UVH compared to controls suggesting lower diastolic suction which can impact overall filling dynamics. Clinical perspective What is new Blood speckle tracking echocardiography provides non-invasive estimation of intraventricular pressure difference in early diastole using two-dimensional blood flow velocities Intraventricular pressure difference based on blood speckle tracking is highly feasible, accurate and reproducible Blood speckle tracking demonstrates significantly reduced intraventricular pressure difference in early diastole in children with univentricular hearts indicating impaired relaxation and suction in these patients What are the clinical implications Intraventricular pressure difference based on blood speckle tracking is a novel and potential sensitive echocardiographic parameter to describe early diastolic ventricular relaxation and diastolic function in children with univentricular hearts Blood speckle tracking could improve assessment of diastolic function in children with congenital heart disease Non-invasive estimation of intraventricular pressure difference based on blood speckle tracking could improve assessment of diastolic function both in children and adults with heart disease
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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 | 0.007 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 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".