A new angle on the Angle of Louis

Area of Science:

• Cardiology
• Medical Imaging
• Anatomy

Background:

• The sternal angle (Angle of Louis) is a common landmark for estimating right atrial pressure.
• Previous literature suggests a fixed 5 cm distance from the sternal angle to the right atrium center, irrespective of patient positioning or body habitus.

Purpose of the Study:

• To measure the distance from the Angle of Louis to specific right atrial locations.
• To determine if this distance varies with patient body habitus (weight, BMI).

Main Methods:

• Cross-sectional study involving 52 consecutive patients.
• Computed tomography (CT) scans were utilized for measurements.
• Correlation analysis between Angle of Louis-to-right atrium distances and patient body habitus characteristics.

Main Results:

• A positive correlation was observed between patient weight or body mass index (BMI) and the measured distances.
• The standard 5 cm estimation can lead to underestimation of right atrial pressure in obese individuals.

Conclusions:

• The fixed 5 cm rule is unreliable for estimating right atrial pressure in patients with higher BMI.
• In morbidly obese patients (BMI > 35 kg/m2), jugular venous pressure at the clavicle may indicate significantly elevated pressures requiring clinical assessment.