Relaxing effect on radial arterial spasm in coronary artery bypass graft: A comparison among nitroglycenn,verapamil and paraverine

Yan ZHU; Xiaochen WANG; Xinmin LI; Hongyu ZHU; Tianxiang GU; Zongtao YIN

ABSTRACT

BACKGROUND; As the bridge vessel, radial artery is easy to occur spasm and injury of endometrium, and the abnormal proliferation of endometrium, re-vasospasm, etc. appear at early period postoperatively, which can affect the operative outcomes.

OBJECTIVE:

To compare the effects of nitroglycenn (NTG), verapamil (VP), paraverine (PA), and the mixture of NTG and VP on relaxing spasm of radial artery in human being.

DESIGN:

A randomized controlled trial.

SETTING:

Department of Cardiosurgery, General Hospital of Shenyang Military Area Command of Chinese PLA.

PARTICIPANTS:

Thirty patients who underwent coronary artery bypass graft (CABG) with autologous radial artery, were selected from the Department of Cardiosurgery, General Hospital of Shenyang Military Area Command of Chinese PLA from September to November in 2006, including 18 males and 12 females, 48-74 years of age. Informed consents were obtained from all the patients or their relatives preoperatively.

METHODS:

① The samples of human radial artery in CABG were collected, and totally 95 vascular rings were used in this study. The rings were divided into five groups NTG group, VP group, PA group, VP+NTG group and control group.There two parts of the experiment, vasospasm relaxation test and vasospasm prevention test. The vascular rings in the control group were only immersed in the Krebs- Ringer solution without any drug. ② Drugs NTG was purchased from Solo Pak Laboratories (Franklin Park, IL), PA from Eli Lilly & Co., (Indianapolis, IN), VP and others from Sigma (St.Louis, MO). ③ Thirty vascular rings were used in the vasospasm relaxation test, and the method of bath chamber was applied. Deoxyepinephrine (terminal concentration of 1 ×10-3 mol/L) was added to stimulate the contraction and spasm of the vascular rings, then four vasodilatators were added, the concentrations of VP and NTG were 30 μmol/L, and that of PA was 0.1%. Relaxation rate=(resting tension after stimulation-initial resting tension)/initial resting tension× 100%. ④ The other 60 vascular rings were used in the vasospasm prevention test. Firstly, the rings were immersed in the four solutions of vasodilatators of corresponding concentrations and Krebs- Ringer solution respectively for 30 minutes. After pretreatment, the vascular rings were randomly divided intc normothermia group (n =30) and cryopreservation group (n =30). In the cryopreservation group, the vascular rings were put into the Krebs-Ringer buffer solution at 4 ℃, and kept in refrigerator at 4 ℃ for 24 hours. The spasms of radial artery were observed.MAIN OUTCOME

MEASURES:

Changes of resting tension (degree of contraction and relaxation rate of dilatation) of vascular rings before and after administration.

RESULTS:

① Effect on the dilatation of spastic radial artery The radial artery was completely within 11 minutes in all the VP+NTG group, VP group, NTG group and PA group. But in the first 3 minutes, the dilating effects of VP+NTG and NTG were obviously better than the other two groups. The dilatation curves showed that the dilating ability in order was VP+NTG ＞ NTG ＞ VP ＞ PA. ② Effect of pretreatment of radial artery on antispasm In the normothermia group, the contractility of the vascular ring produced by 1 ×10-3 mol/L deoxyepinephrine was close between the VP+NTG group and VP group [(0.47±0.06), (0.49±0.08) g, P ＞ 0.05], which were obviously different from those in the NTG group and PA group [(0.81±0.22), (0.87±0.26) g, P ＜ 0.05]. After cryopreservation for 24 hours, the contractility in the VP+NTG group was not obviously different from that in the VP group [(0.86±0.11), (0.90±0.13) g, P ＞ 0.05], and obviously lower than those in the NTG group, PA group and control group [(4.82±0.87), (5.00±0.53), (5.10±0.67) g, P ＜ 0.01], whereas those in the NTG group and PA group were close to that in the control group (P ＞ 0.05).

CONCLUSION:

The drugs can prevent and relax the spasm of radial artery to different extents, whereas considering from preventing spasm and the time-effect of treatment, the mixture of VP and NTG seems to be more proper as the preparation solution for the treatment of radial artery in CABG.