Definition of TAPSE
TAPSE (Tricuspid Annular Plane Systolic Excursion) is an echocardiographic measurement used to evaluate right ventricular (RV) systolic function. It measures the distance that the tricuspid valve annulus (the "ring" around the valve) moves toward the apex of the heart during systole (contraction).
Since the right ventricle’s contraction is primarily longitudinal (shortening from base to apex), TAPSE serves as a reliable surrogate for how well the RV is pumping.
Landmarks for Measurement
To measure TAPSE accurately, clinicians use M-mode (Motion mode) to track the vertical movement of a specific point over time.
- View: Apical 4-Chamber View – The heart is imaged from the bottom up so that all four chambers are visible.
- Measurement Point: The Lateral Tricuspid Annulus – This is the junction where the tricuspid valve meets the outer (free) wall of the right ventricle.
- Alignment: The Cardiac Apex – The M-mode cursor (sampling line) must be placed through the lateral annulus and aligned as parallel as possible to the RV free wall, pointing toward the apex.
Step-by-Step Measurement
- Freeze the M-mode trace once a clear, consistent wave-like motion of the annulus is visible.
- Identify End-Diastole: The "trough" or the highest point on the trace before contraction begins.
- Identify End-Systole: The "peak" or the lowest point of displacement toward the apex.
- Measure: The vertical distance between these two points, typically recorded in millimeters (mm) for neonates.
Measure the distance the annulus travels towards the apex, if the probe is not at the apex you will only get a fraction of TAPSE. For TAPSE get M Mode from apex to the tricuspid annulus.
Reference: Determinación de valores normalizados del desplazamiento sistólico del plano del anillo tricuspídeo (TAPSE) en 405 niños y adolescentes españoles Iván J. Núñez-GilabMaría Dolores RubiocAntonio J. CartóncPedro López-RomerodLucía DeiroscLuis García-GueretacCarlos LabranderocFederico Gutiérrez-Larrayac
PPHN Severity Table with TR and TAPSE
The following table integrates oxygenation, pressure (TR), and functional (TAPSE) markers for a full-term newborn (~38–41 weeks).
| Severity Level | Oxygenation Index (OI) | TR Velocity (m/s) | TR Gradient (mmHg) | TAPSE (mm) | Septal Position |
|---|---|---|---|---|---|
| Normal | < 5 | < 2.5 m/s | < 25 mmHg | > 8.8 mm | Round |
| Mild | <15 | 2.8 – 3.3 m/s | 32 – 44 mmHg | ~ 7.0 – 8.5 mm | Flat (Slight) |
| Moderate | 15 – 25 | 3.4 – 3.9 m/s | 45 – 60 mmHg | 4.0 – 7.0 mm | Flat (Marked) |
| Severe | > 25 | > 4.0 m/s | > 60 mmHg | < 4.0 mm | Bowed into LV |
Key Relationships in PPHN
- TAPSE (Function Indicator): While TR tells you how high the pressure is, TAPSE tells you if the heart can handle it. A high TR velocity with a normal TAPSE suggests the RV is compensating well. A high TR velocity with a TAPSE < 4 mm suggests the RV is failing (uncoupling).
- The "Pop-off" Effect: If a newborn has a large Patent Ductus Arteriosus (PDA), the TR velocity might actually look lower than expected because the high pressure is "escaping" into the systemic circulation. In these cases, clinicians rely more heavily on TAPSE and IVS bowing to judge severity.
Clinical Cut-off Summary
- Critical TR Gradient: >60mmHg (often equal to or higher than systemic blood pressure).
- Critical TAPSE: <4.0mm, which is the primary predictor for ECMO requirement in severe PPHN.
In preterm infants, evaluating PPHN severity requires gestational age-adjusted norms because "normal" values are significantly lower than those in full-term babies. As a preterm baby develops, their normal TAPSE increases and their typical TR velocity thresholds for hypertension shift.
PPHN Severity in Preterm Infants (Approx. 26–34 Weeks GA)
The following values are adjusted for the smaller heart and lower systemic pressures characteristic of preterm neonates.
| Severity Level | Oxygenation Index (OI) | TR Velocity (m/s) | Estimated RVSP (mmHg)* | TAPSE (mm) | Septal Position |
|---|---|---|---|---|---|
| Normal | < 5 | < 2.0 – 2.2 m/s | < 20 – 25 mmHg | > 4.5 – 6.0 mm | Round |
| Mild | <15 | 2.3 – 2.7 m/s | 26 – 35 mmHg | ~ 4.0 – 5.0 mm | Flat (Slight) |
| Moderate | 15 – 25 | 2.8 – 3.2 m/s | 36 – 45 mmHg | 3.0 – 4.0 mm | Flat (Marked) |
| Severe | >25 | > 3.3 m/s | > 45 – 50 mmHg | < 3.0 mm | Bowed into LV |
*Estimated RVSP calculation assumes a Right Atrial Pressure (RAP) of ~5 mmHg.
Critical Differences for Preterm Infants
- Lower Normal Baseline: A "normal" TAPSE for a 26-weeker is only ~4.4 mm. For these micro-preemies, a TAPSE of 3.5 mm might only be "mildly" reduced, whereas in a term baby, that same 3.5 mm would be a critical emergency.
- Reduced Pressure Thresholds: Because preterm babies have lower systemic blood pressure, a TR velocity of 3.3 m/s (gradient of ~44 mmHg) often represents "suprasystemic" pressure, making it clinically severe. In term babies, severe thresholds usually start closer to 4.0 m/s.
- PDA Interference: Preterm infants frequently have a large Patent Ductus Arteriosus (PDA). This "shunts" pressure away from the heart, which can make TR velocity look falsely "normal" even when the pulmonary resistance is dangerously high. In these cases, the Septal Position (flattening) is often the more reliable sign of PPHN.
- Critical Cut-off: While < 4.0 mm is the "red flag" for term infants, neonatologists often look for a Z-score < -2 for the specific gestational age to define severe dysfunction in preterm babies.
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