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Thursday, July 12, 2018

How well do the Echo guidelines work to estimate cardiac filling pressures ?

Elevated filling pressure is thought to define heart failure as it is thought to be the driver for exercise intolerance and shortness of breath.

Filling pressures can be invasively determined by catheters in either the pulmonary artery wedge position or in the left ventricle.

One of the major aims of echocardiography is to provide reliable estimate of filling pressures .It is generally accepted that echocardiographic indices are more effective in determining  filling pressures in patients with reduced ejection fraction (EF) and is more problematic in patients with preserved EF

The 2009 echo guides  for determination of diastolic function were revised in the 2016 guidelines and both  have been the target of some criticisms.

IMO a 2015 article ( 2) from the Cleveland Clinic offers data that raises reasonable concerns about the estimation of filling pressure in patient with preserved EF.It should be noted that the classification system of degrees of diastolic dysfunction (DD) used by the authors is not the exact system proposed by the 2016 guidelines. but rather those of the 2009 guidelines.(1) and the athors criticism relate specifically to the 2009 system.However I believe their conclusion ( see below) regarding the basic underlying paradigm holds regardless of tweeks made to the 2009 guidelines.

The authors reviewed 460 consecutive patients who underwent echocardiography within 24 hours of elective left heart catheterization.

Their figure 5 plots left ventricular diastolic pressure (LVEDP) against normal and the 3 grades of DD in patients with EF greater than 50 % and those with EF less than 50%.In both groups there was no difference in LVEDP between normals and those with Grade 1 and Grade 2. The only statistically significant difference was that between normals and those with grade 3  DD who had EF less than 50%.

The authors conclude: "the findings of this study question the notion that DD is a predictable, progressive process beginning with impaired relaxation followed by reduced compliance and increased filling pressures. The prognostic value of echo graded DD may relate more to its reflection of intrinsic properties of the left ventricle, or to exercise hemodynamics  than to its correlation with resting hemodynamics alone. "A Mayo Clinic study  of 467 patients ( 3) by Kane et al found that
reported no higher pulmonary artery systolic pressure at rest  or on  exercise in those patients with the echo diagnosis of impaired relaxation.



 1) Nagueh, SF Recommendations for the evaluation of left ventricular diastolic function by echocardiography. J Am Soc Echo 2009, 22, 107


2) Grant A, Grading diastolic function by echocardiography:hemodynamic validation of the existing guidelines. Cardio Vascular Ultrasound 2015.


3)Kane, GC et al Impact of age on pulmonary systolic pressure at rest and with exercise.Echo Research and Practice, 2016,3(2) 53-61

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