Objective To compare milrinone （MIN）, Phenoxybenzamine （PHE），and mixture of nitroglycerin and verapamil(NVC) for the prevention and treatment of human radial artery spasm. Methods Residuary radial arteries from 30 patients undergoing coronary artery bypass grafting （CABG） using autologous radial artery from March to September of 2012 in General Hospital of Shenyang Military District were collected. All the artery specimens were cut into 60 vessel rings of 3 mm in width and hanged in the Organ-Bath. Using a random number table，all the vessel rings were divided into 4 groups：PHE group，NVC group，MIN group and blank group （control group）. Firstly，20 vessel rings were used for spasm relaxation experiment with 5 rings in each group. Phenylephrine was added into the Organ-Bath to reach final concentration of 10-3 mol/L in order to cause vessel rings spasm. PHE of 1 mmol/L，NVC of both 30 μmol/L，MIN of 30 μmol/L and Krebs-Ringer’s solution were added respectively into above groups to compare the relaxant effect of these vasodilators on radial artery spasm. Secondly，the other 40 vessel rings were used for spasm prevention experiment with 10 rings in each group. All the 40 vessel rings were dipped in above 4 groups. After 30 minutes，phenylephrine was added to the Organ-Bath to reach final concentration of 10-3 mol/L. Time-dependent constriction of the vessel rings were compared to examine the prevention effect of these vasodilators on radial artery spasm. Results In the spasm relaxation experiment, vessel ring spasm relaxed most quickly in NVC group （P＜ 0.01）. Vessel rings in MIN group relaxed more slowly but steadily （P＜ 0.05）. Vessel rings in PHE group relaxed most slowly （P＜0.01）. And there was no relaxation in the control group. In the spasm prevention experiment，vessel rings in the control group contracted （spasm） 100% immediately after phenylephrine administration. Vessel rings in MIN group contracted immediately after phenylephrine administration too，but slower than the control group（P＜0.01）. Vessel rings in NVC group did not contract right after phenylephrine administration，but the sedentary tension of these vessel rings gradually increased 120 minutes after phenylephrine administration，and vessel ring contraction reached 46.89% 240 minutes after phenylephrine administration. There was no vessel ring contraction in PHE group. Conclusions All the vasodilators in our experiment are effective for the prevention and treatment of radial artery spasm to different degree，but each medication has its own characteristics，vasodilatation result and time-dependent effect. NVC is most effective to dilate radial artery which has been in spasm state, while radial artery pretreated by PHE is least to become spasm after being stimulated.
Abstract： Objective To use tissue Doppler strain rate imaging to evaluate the impact of low dose dopamine and milrinone on systolic and diastolic function of the left ventricle of patients undergoing heart valve replacement. Methods Forty patients undergoing selective heart valve replacement in West China Hospital of Sichuan University between March and May 2011 were included in this study. All the patients were randomized into 2 groups with 20 patients in each group： milrione group and dopamine group. After anesthesia induction and before cardiopulmonary bypass setup， left ventricular ejection fraction （LVEF） was measured by echocardiography. Tissue Doppler strain rate imaging was used to measure the left ventricular lateral wall and midventricular segment from the four-chamber view， which was compared with Doppler parameters. Results LVEF， ratio of early-diastolic to end-diastolic velocity （E/A） of transmitral flow， ratio of mitral inflow velocity to early diastolic velocity in the annulus （E/Et） of both 2 groups were significantly different between before and after dopamine and milrinone administration （P＜0. 05）. In the milrinone group， 4 segments systolic peak velocity （Vs）， 1 segment early diastolic peak velocity （Ve）， 4 segments late diastolic peak velocity （Va）， 3 segments Ve/Va ratio， 2 segments systolic peak strain rate （SRs）， 2 segments late diastolic peak strain rate （SRa）， and 3 segments early diastolic peak strain rate SRe/SRa ratio after dopamine and milrinone administration were significantly higher than those before dopamine and milrinone administration （P＜0. 05）. In the dopamine group， 4 segments systolic peak velocity （Vs）， 1 segment Ve， 4 segments Va， 1 segment Ve/Va ratio， 2 segments SRs， 1 segment SRe， 1 segment SRa， and 1 segment SRe/SRa ratio after dopamine and milrinone administration were significantly higher than those before dopamine and milrinone administration （P＜0.05）. To compare the milrione group and dopamine group after medication administration， 2 segments Vs， 4 segments Va， 1 segment SRe， 1 segment SRa， 2 segments Ve/Va ratio， and 2 segments SRe/SRa ratio of the milrione group were significantly higher than those of the dopamine group （P＜0.05）， and 1 segment Vs， two segments SRs of the milrione group were significantly lower than those of the dopamine group （P＜0.05）. Conclusion Both milrinone and dopamine can improve left ventricular systolic function of perioperative patients undergoing heart valve replacement assessed by tissue Doppler strain rate imaging， while milrinone can improve the diastolic function of the left ventricle on the long axis more significantly.