ABSTRACT
Objective To evaluate the mean blood flow(MF) and pulsatility index(PI) of individual and sequential sa-phenous vein grafts in posterior descending artery(PDA) in the same patient undergone off-pump coronary artery bypass grafting (OPCABG).Methods 140 patients with coronary artery disease were studied.Sequential surgical technique using single large saphenous vein was used in grafts of diagnostic artery(DIAG)(side-side), obtuse marginal artery(OM)(side-side), and PDA( end-side) .Bulldog clamps were used to temporarily arrest the anastomoses of DIAG and OM near the large saphenous vein .Thus the sequential graft became to the single graft , the MF and PI of PDA were recorded in the simulating single graft by the transit-time flow measurement(TTFM), after that, bulldog clamps were removed and the MF and PI of PDA were recorded again in the real sequential graft.The data were compared.Six months later after surgery, coronary CTA were done in all pa-tients in clinic.Results The MF of single graft and sequential graft was(22.5 ±13.1)ml/min and(22.2 ±12.9)ml/min(P>0.05).The PI of single graft and sequential graft was 2.43 ±0.94 and 2.38 ±0.88(P>0.05).The patency of all grafts is good in all patients after 6 months follows-up.Conclusion There ars no hemodynamic differences between individual and sequential grafts in PDA.It is reasonable that the short-term surgical result is the same in individual and sequential grafts in PDA.
ABSTRACT
Objective To explore the distribution and changes of the upper respiratory tract pressure in the human body under circulatory respiration conditions.Methods An oral-secondary bronchus model was established based on CT images.The pressure distribution at various parts of the model during circulatory respiration and the pressure distribution at the moment of maximum inspiration or expiration were simulated under a respiratory flow of 60 L/min.Results The pressure difference in the upper respiratory tract increased with the respiratory flow.Some positions with special structures,such as pharynx,larynx,trachea,etc.,showed pressure gradient changes,especially between edge of epiglottis to the trachea and upon the bifurcation point of tracheal.Conclusions The air flow motion,including pressure distribution and variation,is related to the anatomy morphological structure of the respiratory tract,and they interactively influence the respiration process.The flow field characteristics of pressure cyclic variation can provide basis for exploring the aerosol deposition and the occurrence and treatment of some respiratory tract diseases.