| IntroductionCoronary artery disease (CAD) is a kind of sever disease threatening human healthy. Off - pump coronary artery bypass graft ( OPCAB) can improve blood flow of myocardium, and then improve heart function. Left ventricular dysfunction is often reversed after OPCAB surgery; however, this change is not easily predicted. Doppler Tissue Imaging ( DTI) can quantitatively evaluate the direction and velocity of regional myocardial motion, and less affected by chest wall and lung, so it is more objective and precise. Acoustic Density (AD) bases on the theory of backscatter. It evaluate the change of tiny structure and pathophysiological functions of myocardium by detecting tiny scatterer. This study evaluated the effect of OPCAB surgery on global and regional myocardial function; before and 10 days after the operation.MaterialsThe study population consisted of 19 patients with CAD performing OPCAB excluding cardiac dysrhythmia, valvular heart disease and congenital heart disease (male 14, female 5, average age 63 ± 8 ). All patients underwent angiocardiography before and 10 days after the procedure. 99mTc - MIBI radionuclidemyocardial perfusion imaging was performed in 9 of them.For all patients, echocardiography measures were performed with the instrument of PHILIPS Sonos 5500 with DTI analysis software and AD analysis system with a 2. 0 4. 0 MHz phased array transducer. Starca m/ SPR SPECT was marked by 99mTc- MIBI.Methods1. All the patients performed each examination before and 10 days after operation respectively.2. Two - dimensional images were obtained in the apical four - chamber view, calculating left ventricular ejective function by modified biplane Simpson' s method.3. AD: start AD -IBS program, keeping all the parameters invariably during the experiment. The ROI was placed at four regions of left ventricle as follow : anteriseptal and post wall at two levels (midventricular and left ventricular base). The following parameters were measured: time - averaged Integrated Backscatter (IBS) , Cyclic Variation of Integrated Backscatter ( CVIB) and standardized Integrated Backscatter (IBS% ).4. DTI; Pulsed wave Doppler tissue imaging was performed from the apical four and two views. The sample volume was placed at six regions of mitral valvular annulus as: anteriseptal, septal, inferior, post, lateral, and anterior wall; and four regions of left ventricle as:anteriseptal and post wall at two levels (midventricular and left ventricular base). Images were obtained in each region : the systolic myocardial maximum velocity (Vs) , systolic velocity integral (S - VTI) , systolic time (Ts) , and S wave acceleration time (TPV).5. 99mTc - MIBI radionuclide myocardial perfusion imaging: giving a mark semi - quantitatively to the uptake of 99mTc - MIBI by regional myocardium.6. Statistical analysis: all data presented as mean value SD. Data acquired was analyzed by SPSS11.5 software.Results1. Increased left ventricular EF was observed (42.02 ±9.18 before OPCAB vs 46.38 ±6.37 10 days after OPCAB, P < 0.05).2. The value of Vs of post wall at midventricular and left ventricular base levels and S - VTI of post wall at left ventricular base level increased after OPCAB (P <0.05) , while the value of Ts and TPV of anteriseptal wall at left ventricular base level decreased (P < 0.05).3. Reduction of IBS and IBS% after the operation was observed at all the myocardial regions studied, while the value of CVIB rose ( P <0.05).4. Vs and S - VTI show negative correlation with the score of SPECT at all the myocardial regions studied ( r = - 0.480, P < 0. 001; r = - 0. 344, P < 0. 05 respectively). IBS and IBS% show positive correlation with the score of SPECT (r = 0.588,P < 0. 001; r = 0. 529, P < 0. 001 respectively) , while CVIB show negative correlation (r = — 0.332,P <0.05).5. M - Vs at septal and lateral sites and M - TPV at anteriseptal lateral sites of mitral valvular annulus increased after OPCAB ( P <0.001). The means of M - Vs and M - S - VTI of mitral valvular annulus show positive correlation with LVEF (r =0.41 ,P <0.05 ;r =0.46,P <0.05 respectively).DiscussionThe pathological changes of coronary artery and increasing oxygen demand of myocardium result in ischemia when there is coronary artery disease. OPCAB surgery can make the stenosis artery recanalization, therefore prove the function of survival myocardium and left ventricular global function.DTI can quantitatively evaluate the direction and velocity of regional myocardial motion, and less affected by chest wall and lung, so it is more objective and precise. AD bases on the theory of backscatter. It evaluate the change of tiny structure and pathophysiological functions of myocardium by detecting tiny scatterer, and reflect systolic function of myocardium. |
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