| Background As a conventional method in diagnosis and risk stratification of coronary artery disease(CAD),test of gated single photon emission computed tomography myocardial perfusion(G-MPI)needs twice acquisition of perfusion images at rest and after stress.Traditional stress methods include exercise and pharmacological stress and exercise treadmill test is the most frequently used exercise test.Due to different mechanism,pharmacological stress can be divided into vasodilators such as adenosine,dipyridamole and positive inotropic agents such as dobutamine.Like exercise stress test,myocardial ischemia can be induced by pharmacological stress test of dobutamine due to its influence on heart rate and blood pressure.Agents of vasodilators like adenosine do not directly induce myocardial ischemia but through perfusion difference between normal and stenosed coronary arteries,which then leads to perfusion defect on images.Recently,several studies have found that phenomenon of left ventricular dyssynchrony can be measured by G-MPI.Left ventricular dyssynchrony parameters can be acquired by a SPECT based G-MPI phase analysis technique developed jointly by Emory university and our department.This technique divides contraction phase of left ventricle into 8 or 16 gates and dyssynchrony parameters were obtained using calculations of Fourier transformation and has already been widely used clinically in heart failure patients to find out whether dyssynchrony of left ventricle exists.So far,this phase analysis technique has been applied in best lead position of cardiac resynchronization therapy when combining with parameters of cardiac scar from conventional perfusion images.Equivalent diagnosis and risk stratification value of different stress tests have been confirmed by several former studies.However,no studies yet have focus on the influence of phase analysis and dyssynchrony parameters of CAD patients.Objective To compare the influence of different G-MPI stress methods of exercise and adenosine on left ventricular contraction dyssynchrony parameters in CAD patients and to further figure out whether left ventricular dyssynchrony parameters of different stress methods are clinically interchangeable.Methods 42 patients undergone two day rest/stress methoxyisobutylisonitrile sestamibi(99mTc-MIBI)SPECT G-MPI in our center from September 2010 to September 2017 were consecutively enrolled,among whom 21 received exercise treadmill test and the other 21 patients received adenosine stress.All patients were diagnosed with CAD by reversible perfusion on stress/rest SPECT and received CAG or coronary CTA three months before or after the test of G-MPI.31 patients undergone CAG have coronary stenosis ≥50% and the other 11 patients undergone coronary CTA all have coronary stenosis ≥65%.Dyssynchrony parameters of Phase Standard Deviation(PSD),Phase Histogram Bandwidth(PBW),phase histogram skewness(skewness)and phase histogram kurtosis(kurtosis)were acquired through MPI Quantification Toolbox.Functional parameters of Left Ventricular End Diastolic Volume(LVEDV),Left Ventricular End Systolic Volume(LVESV)and Left Ventricular Ejection Fraction(LVEF)were acquired at the same time.Parameters after stress were used for statistical analysis and comparison.Independent sample t test was applied in calculation.Results No statistical differences(p>0.05)were found between two groups of exercise and adenosine in baseline characteristics including age(60.43±5.70 year vs.61.43±6.67 year,p=0.604),male(11 vs.10,p=0.758),history of hypertension(17vs.16,p=0.707),diabetes mellitus(4 vs.4,p=1.000),smoking(7 vs.6,p=0.739)and coronary stenosis(left main artery: 0 vs.2,p=0.488;left anterior descending: 20 vs.17,p=0.343;left circumflex artery: 8 vs.6,p=0.513;right coronary artery: 8 vs.11,p=0.352;diagonal artery: 5 vs.7,p=0.495;obtuse marginal artery: 2 vs.4,p=0.663).No statistical differences(p>0.05)were found between two groups in dyssynchrony parameters after stress of PSD(13.14±6.14° vs.11.67±4.22°,p=0.372),PBW(48.95±21.65° vs.44.95±13.80°,p=0.478),skewness(3.96±0.70 vs.3.84±0.67,p=0.556)and kurtosis(19.74±7.17 vs.18.37±5.68,p=0.494),respectively.No statistical differences were found between two groups in functional parameters after stress of LVEDV(77.67±22.03 ml vs.78.43±25.28 ml,p=0.918),LVESV(27.62±14.40 ml vs.27.90±12.53 ml,p=0.946)and LVEF(66.48±9.64% vs.65.38±7.40%,p=0.682),respectively.Conclusion Both exercise and adenosine are common stress methods in SPECT G-MPI and no statistical differences were found in dyssynchrony parameters induced by both two methods in CAD patients,which indicates the clinically interchangeable utility of these two stress methods. |
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