Coronary flow reserve assessment

Pawel Petkow Dimitrow

2nd Department of Cardiology
Jagiellonian University School of
Medicine, 17 Kopernika Str.,
31-501 Cracow, Poland
E-mail address: dimitrow{at}mp.pl

Marek Krzanowski

Department of Medicine, Jagiellonian
University School of Medicine,
8 Skawinska Str., 31-066 Cracow,
Poland

We would like to add some comments to an interesting paper of Voci et al.1 Apart from the anterior and posterior descending coronary artery, it is possible to visualize transthoracically proximal and middle segments of the circumflex coronary artery and all three segments of the right coronary artery.25 The images other than from the apical windows are obtainable.4

Reduction of coronary flow reserve (CFR) depends not only on severity of stenoses in epicardial arteries but also on a number of ‘microvascular factors’ which either limit maximal vasodilatation or increase baseline coronary blood flow.2,6 In the absence of stenosis in the epicardial coronary artery, decreased CFR enables the detection of impaired microvascular vasodilatation in left ventricular hypertrophy (hypertension, aortic stenosis, and hypertrophic cardiomyopathy) diabetes mellitus, hypercholesterolaemia, smoking, and syndrome X.2,6 Importantly, epicardial coronary artery stenosis and microcirculation abnormalities may co-exist and cumulatively decrease the CFR. It is possible to distinguish the haemodynamic effect of stenosis of epicardial coronary artery from microcirculation abnormalities in order to identify cases with moderate stenosis in which coronary intervention can correct the abnormalities of blood flow. For this purpose, a stenosis-specific parameter, i.e. the accelerated coronary flow velocity at the site of stenosis, is measurable.36 Voci et al. reasonably stated that acceleration at the site of stenosis depends not only on the severity of stenosis but also on other factors altering the velocity gradient. Accordingly, we suspected that universal borderline velocity discriminating non-stenosed from stenosed arteries probably does not exist and rather a method of ‘standardization’ of velocity assessment should be used. Our data3,5 support suggestions that, in stenosis detection, a velocity ratio (i.e. a ratio of maximal velocity within the stenosis and immediately proximal to it) is more reliable than any single velocity measurement. We successfully used the criteria valid for peripheral arteries where local velocity increase with at least doubling of velocity within the stenosis is regarded as a sign of haemodynamically significant stenosis.

Finally, we would like to mention that coronary endothelium-dependent vasodilatation is also measurable by transthoracic Doppler echocardiography.7

References

  1. Voci P, Pizzuto F, Romeo F. Coronary flow: a new asset for the echo lab? Eur Heart J 2004;25:1867–1879.[Free Full Text]
  2. Dimitrow PP. Coronary Flow Reserve—Measurement and Application: Focus on Transthoracic Doppler Echocardiography. Boston/Dordrecht/London: Kluwer Academic Publishers; 2002.
  3. Krzanowski M, Bodzon W, Brzostek T, Nizankowski R, Szczeklik A. Value of transthoracic echocardiography for the detection of high-grade coronary artery stenosis: prospective evaluation in 50 consecutive patients scheduled for coronary angiography. J Am Soc Echocardiogr 2000;13:1091–1099.[CrossRef][ISI][Medline]
  4. Krzanowski M, Bodzon W, Dimitrow PP. Imaging of all three coronary arteries by transthoracic echocardiography: an illustrated guide. Cardiovasc Ultrasound 2003;1:16.[CrossRef][Medline]
  5. Krzanowski M, Bodzon W, Dudek D, Heba G, Rzeszutko M, Nizankowski R, Dubiel J, Szczeklik A. Transthoracic, harmonic mode, contrast enhanced color Doppler echocardiography in detection of restenosis after percutaneous coronary interventions. Prospective evaluation verified by coronary angiography. Eur J Echocardiography 2004;5:51–64.[CrossRef]
  6. Dimitrow PP. Transthoracic Doppler echocardiography—noninvasive diagnostic window for coronary flow reserve assessment. Cardiovasc Ultrasound 2003;1:4.[CrossRef][Medline]
  7. Dimitrow PP, Krzanowski M, Grodecki J, Malecka B, Lelakowski J, Kawecka-Jaszcz K, Szczeklik A, Dubiel JS. Verapamil improves the endothelium-dependent vasodilatation in patients with hypertrophic cardiomyopathy. International J Cardiol 2002;83:239–247.[CrossRef][ISI]




This Article
Full Text (PDF)
All Versions of this Article:
26/8/849    most recent
ehi211v1
Alert me when this article is cited
Alert me if a correction is posted
Services
Email this article to a friend
Similar articles in this journal
Similar articles in ISI Web of Science
Similar articles in PubMed
Alert me to new issues of the journal
Add to My Personal Archive
Download to citation manager
Request Permissions
Google Scholar
Articles by Dimitrow, P. P.
Articles by Krzanowski, M.
PubMed
PubMed Citation
Articles by Dimitrow, P. P.
Articles by Krzanowski, M.