How reliable is E/E ratio in Acute decompensated HF

[Cadet133]

When clinical suspicion for HF is intermediate in patient with dyspnea and cardiac risk factors but no exam findings to support (JVD, Edema etc) How reliable is E/E ratio on ECHO to gauge the PCWP?? IS it reliable in patients with chronic systolic CHF?

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[Rocher]

When clinical suspicion for HF is intermediate in patient with dyspnea and cardiac risk factors but no exam findings to support (JVD, Edema etc) How reliable is E/E ratio on ECHO to gauge the PCWP?? IS it reliable in patients with chronic systolic CHF?

I'm not a huge echo guy but am board certified in it so will take a stab. Your badge says medical student so I'll give some background which is required to understand where it is useful and where it isn't.

It's E/e' rather than E/E, and the way it works is you measure the velocity of the mitral inflow (E, blood moving across the mitral valve in diastole) and measure the velocity of the medial and lateral mitral valve annuli in diastole (the average is the e' and is tissue velocity rather than blood velocity). If the mitral inflow is high, there is brisk blood movement across the mitral valve due to a high pressure gradient, which may be due to high left atrial pressure. If the e' is low, it suggests poor cardiac relaxation and the combination of both of these points toward elevated left atrial filling pressure.

The E/e' doesn't really gauge PCWP but can suggest if LA filling pressure is high if the number is >15 (number does not correlate with pressure in mmHg). There are several reasons it can be unreliable, including poor measurement, mitral annular calcification, significant mitral regurgitation, among others. Looking at the inferior vena cava diameter and variation with the respiratory cycle can also help. If the diameter is >2.1 cm and there is <50% reduction in IVC diameter with a sniff (reduces intrathoracic pressure) then the RA pressure is likely >15 mmHg and that points toward decompensated heart failure (also with caveats).

Heart failure is a clinical diagnosis and you really have to put all of the pieces together to determine if someone is volume overloaded. Elevated E/e' in itself is probably not very reliable if there are no other signs of heart failure, but many people miss elevated JVP. I will occasionally use a point of care ultrasound to look at the neck veins in very obese people since it can be pretty hard to tell sometimes.

To answer the last part of your question, E/e' is useful in chronic heart failure.

Hope that was helpful!