Clinical Relevance of “Volumetric/echo”

vs. “Pressure transducer using”   techniques  

with Exercise

for estimating LV diastolic function

in Myocardial Disease  Patients 

Although LVP diastolic measures are widely accepted and used as gold standard, only “pure volumetric” Doppler echocardiographic diastolic indexes are used in clinical practice and are included in all “Recommendations for evaluating LV diastolic function”.

However, several thorough studies have shown in last years how “misleading” is the information that we get using exclusively the “pure volumetric sophisticated Doppler velocities”....

So many millions of $ and so many years of intensive research have been spent and so many lectures on “Diastology” have been enthusiastically held in overcrowded arenas.. for introducing “new Doppler echocardiographic technologies” and trying to establish their clinical application for accurately estimating LV diastolic function; whereas  myriads of “diastolic indexes” have been introduced and >90% of them soon “abandoned” (!)…

The present blog summarizes an alternative concept of “diastolic stress test” using external pressure transducers, which has been proved not to have the profound limitations of “imaging diastolic tools”, above with exercise..

Namely, several cath studies in last decade have proved that Doppler indexes –incl. E/E’- are showing not only a great variability with scattering in a wide “normal range”, but above no or only poor correlations with accepted invasive measures of LV compliance and relaxation. Most recently, in a superb editorial, it has been concluded that the widely used E/E’ is providing even in advanced hear failure.. ”misleading information about left-sided filling pressures” …

Although my blog might seem “provocative” to many “echo-diastologists” by comparing  “very sophisticated/modern” techniques with “very simple/old-fashioned” diastolic stress test, some pathophysiologic truths should not be forgotten:  Doppler indexes are estimating  pressure differences and velocities, whereas Pressure transducer derived indexes reflect unidirectionally corresponding LVP curve changes and LV filling pressures level...

Specifically, when operating in the steep part of PV relationship, changes in “stiffness” of arterial or left ventricular wall cannot be estimated without “pulse pressure” transducers.  Thus, “mechanocardiographic techniques” (“Carotid pulse/Pulse wave velocity” and Pressocardiography, respectively) are really essential and not replaceable by any imaging/pure volumetric technique.

Diastolic Types based on exact pressocardiographic criteria of A wave to total height (A/H) and total relaxation time (TORET) or/and TORET index (HR correction); the extreme TORET prolongation is typical for Cardiomyopathies and the isolated A/H increase for diastolic heart failure or ischemia.   

Starting in early 70s, some giants of US cardiology, have extensively proved that pressocardiograms are closely related in slope, time and “A wave pulse amplitude” to LVP curve and that A wave indexes show close correlations with LVEDP, LAP and stiffness indexes. In 80s, the “total relaxation time” of pressocardiogram has been shown to correspond to that of LVP.

Using optimal external pressure transducers with low level handgrip stress and based on exact criteria, we have first explored the challenging  “Diastolic Stress Test” concept since >20 years and published data from a wide spectrum of myocardial disease states, above CAD. Pressocardiograms with handgrip (presso test) show often in CAD patients an almost identical diastolic pattern characteristic high-magnitude changes with that of LVP curve in presence of ischemia. Recently, an automated evaluation of diastolic patterns based on presso test data could be developed and successfully applied in clinical practice for differentiating an “ischemic” from a “non-ischemic” pattern of diastolic response.

In recent years, the “diastolic stress test” concept has been tried using TDI with dynamic exercise; however, although even whole sessions have been organized –as in the last annual ESC meeting, the results are really frustrating. A thorough analysis of the real reasons of this obvious failure is given also in this review.  

Thus, there is a clear need for better and simpler non-invasive methods for triaging pts with latent diastolic dysfunction in myocardial disease states and specifically CAD. “Diastolic stress test” can greatly help in this setting, but only with use of a pressure transducer and exact definitions of diastolic patterns of LV diastolic behaviour, as published data have shown.

From my personal extensive experience with >7.000 presso tests in last 25 years, I am sure that this test might become a really very useful tool for every practitioner in daily practice in these settings and, therefore, further research should be initiated in this field....

                      Diastolic Stress Test

                         Using

       External Pressure Transducers

                 &   Handgrip Exercise 
                   -Presso Test -                     

                           

In following, some Typical Examples of Presso Tests:

                                Healthy Subject



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Asymptomatic CAD -LAD-65% 

At Rest: All indexes within normal limits; At 2 min Handgrip: A/H rise by 167% of baseline value; typical "ischemic diastolic response" similar to LVEDP rise [Ischemic Compliance-(C) type of response & Coronary Differential form].

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                                        Asymptomatic

                Nonocclusive CAD

   

At Rest: All diastolic indexes within normal; At 2min Handgrip: moderately prolonged Relaxation Time (TORET) by 25% of  baseline due to induced ischemia [Ischemic Relaxation (R)-type, Coronary Differential form]
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       Heart Failure without Ischemia

At Rest: Inceased A wave; At 2 min Handgrip: decreasing A wave due to left atrial failure and/or HR rise [Non-ischemic C-type & "Congestive Differential form] 
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