Strain echocardiography tracks dobutamine-induced decrease in regional myocardial perfusion in nonocclusive coronary stenosis.
OBJECTIVE
This study was designed to determine whether strain echocardiography parameters reflect changes in regional myocardial perfusion during dobutamine stress.


BACKGROUND
Strain echocardiography depicts regional myocardial mechanical activity. Ischemia has been shown to reduce systolic strain rate (sSR) and prolong the time to regional lengthening (T(RL)). In an experimental model, we tested whether sSR and T(RL) tracked dobutamine-induced changes in regional myocardial perfusion (regional myocardial blood flow [RMBF]), as measured by colored microspheres.


METHODS
We used a closed-chest pig model of nonocclusive coronary stenosis (n = 14) created by inflating an angioplasty balloon in the proximal left anterior descending artery. Invasive hemodynamics, RMBF, and strain parameters were measured at baseline and peak dobutamine stimulation before and during the coronary stenosis. We compared segments with reduced RMBF versus those with preserved RMBF at peak dobutamine stimulation.


RESULTS
Peak sSR correlated with RMBF (r = 0.70). In the absence of coronary stenosis, dobutamine stimulation caused a significant increase in RMBF and sSR and a decrease in T(RL). This response was blunted during coronary stenosis. Using the "best cutoff" method, the sensitivity and specificity for prediction of reduced RMBF (ischemia) was 81% and 91% for sSR and 65% and 91% for T(RL), respectively. These changes occurred in the absence of any change in global systolic and diastolic function (dP/dT(max), dP/dT(min), and tau).


CONCLUSIONS
Novel strain parameters that depict regional myocardial mechanics are able to predict changes in RMBF during dobutamine stress. Quantitative strain parameters may complement current echocardiographic techniques for ischemia detection and potentially improve the accuracy and reproducibility of stress echocardiography.
Division of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Gabriel
G
Yip
Bijoy
B
Khandheria
Marek
M
Belohlavek
Cristina
C
Pislaru
James
J
Seward
Kent
K
Bailey
A Jamil
AJ
Tajik
Patricia
P
Pellikka
Theodore
T
Abraham
D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004195:Disease Models, Animal; D004280:Dobutamine; D025401:Echocardiography, Stress; D005260:Female; D006339:Heart Rate / Q000502:physiology; D009200:Myocardial Contraction / Q000502:physiology; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012039:Regional Blood Flow / Q000502:physiology; D013552:Swine
D004280:Dobutamine