| With the rapid development of percutaneous coronary intervention(PCI)technique and persistent improvement of dedicated equipments as well as widelly accepted of minimally invasive PCI,transradial coronary intervention(TRI)has radically advanced over the past two decades.Compared with the conventional femoral artery access,TRI significantly reduced the incidence of local vascular complications,more importantly,which brought overall therapeutic benefits with lower mortality and major adverse cardiac events(MACE)rates,especially for the patients with acute myocardial infarction requiring intensive anticoagulant and antithrombotic therapy.Therefore,radial artery has been employed as the preferred access site in the increasing number of cardiac interventional centers.According to the report published in 2016,the total number of PCI has reached 660,000 procedures,and the proportion of the TRI has reached 90.51%.Moreover,in the experienced cardiac interventional centers,the proportion of the TRI has reached even beyond 95%,which was much higher than the utilization of TRI(approximately 50-60%)in European and American countries.Besides,the type of coronary lesions treated with TRI has been expaned from simple to complex lesions,including left-main lesions,severe calcified lesions,true bifurcation lesions and chronic total occlusion(CTO)lesions,with relative high success rates and favorable results.Despite advantages of TRI mentioned aboved,owing to the intrinsic anatomic characteristics(e.g.,small diameters and abundant elastic fibers in radial artery wall)and physiological property(e.g.,high density in alpha adrenergic receptors,high reactivity to a variety of stimuli and prone to spasm)of radial artery,TRI procedure may damage structure and function of cannulated radial artery to some extent during insertion and removal ofsheaths as well as catheters manipulation.The damages to radial artery included radial artery occlusion(RAO)and non-occlusive injury(e.g.,intimal tear,dissection,spasm and endothelial dysfunction).RAO is usually asymptomatic due to extensive collateral circulation among superficial and deep palmar arches.Therefore,hand ischemia is turely rare in patients with RAO.However,RAO and radial artery non-occlusive injury following TRI procedures may potentially influence the quality as a bypass conduit and limit its use in future repeated TRI.Therefore,the protection of the radial artery and maintenance of endothelial function should be highly relevant for the TRI procedures.Nowadays,for the vast majority of patients undergoing TRI procedure,6French(6-Fr)sheaths and guiding catheters are recommended.It is possible to do most of PCI procedure in ordinary cases through 6-Fr guiding catheters for experts.However,it is sometimes difficult to conduct complex coronary cases through 6-Fr guiding catheters,such as unprotected left main lesions,true bifurcation lesions treated with two-stent strategy,severe calcified lesions required rotational atherectomy as well as CTO lesions required multiple wires,balloons and specialized devices(e.g.,microcatheter,child-mother catheter,1.75-mm or larger burrs,IVUS and OCT)simultaneously in one guiding catheter.Thus,a large-bore sheath(7-Fr)may be required to allow stronger back-up support and better materials delivery with no impact on monitor of hemodynamics and quality of coronary angiography,which could make the procedure easier and perhaps better.Therefore,7-Fr sheath and guiding catheters should be the first choice for those complex coronary lesions mentioned aboved.However,previous study showed the dismatch between radial artery inner diameter and sheath outer diameter was an independent risk factor for RAO after TRI.The study on anatomy of radial artery in Chinese showed that the diameters of 86.1% Chinese people were larger than 6-Fr sheath outer diameters,while the diameters of 59.3% Chinese people were larger than 7-Fr sheath outer diameters.Thus,compared with 6-Fr sheath,whether the application of 7-Fr sheaths via radial artery access couldsignificantly increase the incidence of RAO after TRI? Our previous study showed that 7-Fr sheath did not increase the incidence of RAO at 30 days follow-up after TRI compared with 6-Fr sheath.However,few studies focused on the impact of 7-Fr sheath on long-term RAO after TRI.Besides,theory of“elastic parameter” of radial artery diameters was raised by professor Fu xianghua,which means that diameters of radial artery measured by vascular ultrasound are not settled but variable parameter.The diameter of radial artery could be decreased by stimuli and increased by administration of vasodilatory drugs such as nitroglycerin and verapamil.However,the changes of lumen area,intimal area and medial area with respect to radial artery spasm and intra-arterial nitroglycerin observed by visual imaging examnation(OCT)were not available.Several clinical studies showed that the damage to vascular endothelium caused by TRI could lead to radial artery endothelial dysfunction.Nicorandil is an adenosine triphosphate-sensitive potassium(K-ATP)channel opener with additional properties similar to nitrates.Besides,it has been reported that nicorandil could improve endothelial dysfunction via inhibited production of reactive oxygen species.However,few study was conducted to explore the protective effects of long-term administration of nicorandil on the endothelial function of the radial artery after TRI.This study was divided into three parts.In the first part,the impact of6-Fr and 7-Fr sheaths on the incidence of long-term RAO after TRI was observed by vascular ultrasound.In the second part,the changes of radial artery structure and effects of intra-arterial 200 ug nitroglycerin on lumen area,intimal area and medial area of radial artery after TRI were observed by OCT.In the third part,the effect of long-term administration of nicorandil on endothelial function of the cannulated radial artery in patients with angina undergoing elective TRI was assessed by flow-mediated dilation(FMD)and nitroglycerin-mediated dilation(NMD).Part one Comparison of the Impact of 6-French and 7-French Sheaths on Long-term Radial Artery Occlusion after Transradial Coronary InterventionObjective: The aim of this study was to explore the impact of 6-Fr and7-Fr sheaths on the incidence of long-term radial artery occlusion(RAO)after transradial coronary intervention(TRI)observed by vascular ultrasound.Methods: From September 2013 to January 2016,patients with angina pectoris or evidence of myocardial ischemia and true bifurcation lesions confirmed by coronary angiography(CAG)in the Cardiology Department of the Second Hospital of Hebei Medical University were enrolled in this study.The true bifurcation lesions were defined as the diameter of side branch was larger than 2mm as well as degree of side branch ostium stenosis was beyond75%.All coronary lesions were suitable for PCI treatment in this study.The patients were randomly assigned to 6-Fr group or 7-Fr group immediately after CAG in a 1:1 ratio by computer-generated random numbers.Patients in6-Fr group underwent PCI with 6-Fr sheaths(outer diameter: 2.52 mm,Radifocus,Terumo,Japan),while patients in 7-Fr group underwent PCI with7-Fr sheaths(outer diameter: 2.85 mm,Medtronic,USA)in place of the former6-Fr sheaths.Patients could be crossover to the other group if necessary.Before insertion of 7-Fr sheath,sufficient local subcutaneous anesthesia with lidocaine and intra-arterial nitroglycerin were administrated in order to increase the compatibility between radial artery and sheath.The incidence of RAO and change of radial artery diameters were observed by ultrasound examination at 1 day before TRI as well as 30 days and 1 year after TRI.RAO was defined as an absence of antegrade flow in the radial artery observed by ultrasound.The primary endpoint of study was the incidence of RAO at 1 year after TRI between the two groups.The secondary endpoints of study were the incidence of local vascular complications during hospitalization and changes of radial artery diameters within 1 year after TRI compared with baseline value before TRI between the two groups.Besides,multivariate logistic regression analysis was used to explore the possible factors associated with the incidence of long-term RAO after TRI.Results: A total of 214 patients were enrolled in this study finally,whowere randomly assigned to 6-Fr group(n=105)or 7-Fr group(n=109).There were no significant differences between the two groups about age,gender,body mass index,diabetes,hypertension,smoking,a history of TRI,hyperlipidemia and medications used.Besides,no significant differences were found with respect to the number of puncture attempts,heparin dose,radial artery spasm,forearm hematoma,number of catheters used and duration of compression.The ratio of radial artery inner diameter and sheath outer diameter in 6-Fr group was much higher than that in 7-Fr group(1.09±0.11 vs.0.96±0.13,P<0.001).The procedural time of 6-Fr group was much longer than that of 7-Fr group(74.27±12.58 min vs.66.67±14.72 min,P<0.001).There was no significant difference between the two groups about the incidence of RAO at 1 year after TRI(8.57% vs.12.84%,P=0.313).Besides,no significant difference was observed in the incidence of local vascular complications during hospitalization between the two groups(20% vs.24.77%,P= 0.403).There was no significant difference between the two groups about baseline radial artery diameters(2.74±0.28 mm vs.2.73±0.39 mm,P=0.830).At 1 year follow-up,radial artery diameters in both of 6-Fr and 7-Fr groups were significantly decreased compared with baseline values before TRI(6-Fr group: 2.64±0.27 mm vs.2.74±0.28 mm,P=0.009;7-Fr group: 2.63±0.31 mm vs.2.73±0.39 mm,P=0.031).However,no significant difference was found between the two groups about radial artery diameters at 1 year follow-up(2.63±0.31 mm vs.2.64±0.27 mm,P=0.802).Multivariate logistic analysis showed that repeated TRI was an independent risk factor of long-term RAO at1 year after TRI(OR=10.316,95%CI: 2.928-36.351,P =0.001).Conclusions:1 7-Fr sheath did not increase the short-term and long-term incidence of RAO after TRI compared with 6-Fr sheath.2 No obvious differences were observed between 6-Fr and 7-Fr sheaths about the radial artery diameters at 1 year after TRI,but both of them were significantly decreased compared with baseline values before TRI.3 Repeated TRI was an independent risk factor of long-term RAO at 1year after TRI.Part two Changes of Radial Artery Structure and Vasodilatory Effects of Intra-arterial Nitroglycerin on Radial Artery after Transradial Coronary Intervention Observed by Optical Coherence TomographyObjective: To evaluate the changes of radial artery structure and effects of 200 ?g intra-arterial nitroglycerin on lumen area,intimal area and medial area of radial artery after transradial coronary intervention(TRI)observed by optical coherence tomography(OCT).Methods: From September 2015 to February 2017,patients who underwent coronary OCT imaging for clinical reasons during TRI procedure in the Cardiology Department of the Second Hospital of Hebei Medical University were enrolled in this study.OCT catheter was inserted into forearm and placed at the radial artery ostium through the sheath under fluoroscopic guidance after TRI procedure,then the sheath was extracted to a point that was 3-4 cm proximal to the puncture site,leaving the OCT catheter at the beginning of radial artery.Auto sequential OCT pullbacks were repeatedly performed to examine the radial artery from the ostium to the sheath tip.The middle cross section of entire image length was selected to divide radial artery into proximal and distal segments.The acute injuries(including intimal tear,dissection,spasm and local acute thrombosis)and changes of vessel structure(including lumen area,intimal area,medial area and so on)as well as intimal thickening of radial arteries were compared between first-TRI and repeat-TRI(patients with a past history of TRI)groups.The intimal hyperplasia indexes included intimal thickness index(ITI: intimal area/medial area),intima-media ratio(IMR: the maximum intimal thickness/medial thickness)and percentage of luminal narrowing [%LN:(intimal area+medial area)/external elastic membrane area×100%].Besides,the lumen area,intimal area and medial area of radial artery spasm segment were observed to evaluate the changes of radial artery structure in spasm status.One minute after intra-radial administration of200 ?g nitroglycerin,OCT examination was repeated to evaluate the effects ofnitroglycerin on radial artery by the changes of lumen area,intimal area and medial area.Results: A total of thirty patients were enrolled in this study who underwent OCT investigation of the right radial artery.Twenty patients were naive for TRI(first-TRI group),while ten had a past history of TRI(repeat-TRI group).There were no significant differences in the characteristics of baseline and TRI procedure between the two groups.There was no significant difference in the frequency of radial artery acute injuries after TRI procedure between the two groups.No significant difference was found in the incidence of radial artery acute injuries after TRI procedure between radial artery proximal and distal segments.The intimal area in the repeat-TRI group was significantly larger than that in the first-TRI group in both of radial artery proximal(0.77±0.32mm2 vs.0.43±0.14mm2,P<0.001)and distal(1.09±0.26mm2 vs.0.47±0.20mm2,P<0.001)segments.No statistically significant differences were observed in the comparison of lumen area,medial area and external elastic lamina(EEL)area between the two groups.Besides,the intimal hyperplasia indexes including ITI,IMR and %LN in the repeat-TRI group were significantly larger than those in the first-TRI group in both of radial artery proximal and distal segments.In the spasm segment of radial artery,the lumen area was significant decreased(3.05±1.06mm2 vs.6.17±1.49mm2,P< 0.001),while medial area was significant increased(1.73±0.35mm2 vs.1.46±0.27mm2,P<0.001).Compared with the whole radial artery,the changes of lumen area(41.45±18.82% vs.163.27±32.46%,P<0.001)and medial area(17.27±6.56% vs.37.51±10.54%,P<0.001)after administration of intra-arterial 200?g nitroglycerin were more remarkable in the spasm segment of radial artery.Conclusions:1 The majority of acute radial artery injuries after TRI was radial artery spasm,while intimal tears and dissections only occurred in a small proportion of patients.2 Obvious chronic intimal hyperplasia was observed in the radial arteryafter TRI,especially in the distal segment.3 Intra-arterial nitroglycerin could significantly increase the lumen area and decrease medial area of radial artery,especially in the spasm segment.Part three Effect of Long-term Administration of Nicorandil on Endothe- lial Function of the Radial Artery in Patients with Angina Undergoing Transradial Percutaneous Coronary InterventionObjective: To evaluate the effect of long-term administration of nicorandil on endothelial function of the cannulated radial artery in patients with angina undergoing elective transradial coronary intervention(TRI)by flow-mediated dilation(FMD)and nitroglycerin-mediated dilation(NMD).Methods: From May 2015 to September 2015,patients with angina who underwent elective TRI procedures with a 6-Fr radial sheath(sheath outer diameter: 2.52 mm;Terumo Co,Japan)for the first time in the Cardiology Department of the Second Hospital of Hebei Medical University were enrolled in this study.The patients were randomly assigned to nicorandil group or control group immediately after TRI procedure in a 1:1 ratio by computergenerated random numbers.Patients in nicorandil group received standard medication plus nicorandil 5 mg twice daily,and continued for 3 months after TRI procedure.In control group,patients received standard medication except nicorandil.Radial artery diameter(RAD),FMD and NMD of radial artery were measured at 1 day before TRI as well as 1 day and 3 months after TRI by Ultrasound-Doppler.The changes of FMD and NMD between two groups were applied to assess the effect of long-term administration of nicorandil on endothelial function of radial artery.Results: A total of 127 patients were enrolled in this study,who were randomly assigned to nicorandil group(n=64)or control group(n=63).All patients underwent TRI procedure via right radial artery.There were no significant differences in the characteristics of baseline clinical and TRI procedure between the two groups.No significant difference was observed in the baseline RAD,FMD and NMD between the two groups(all Ps >0.05).In the non-cannulated arm,there was no difference in RAD,FMD and NMDbetween the two groups across the whole study period(P>0.05).In the nicorandil group,FMD at baseline was 11.20±3.30%,which was significantly decreased to 5.83±2.26% at 1 day after TRI(P<0.001).However,at 3 months follow-up,FMD increased to 10.38±2.43%.In addition,no difference was observed in FMD between baseline and 3-month follow-up(P=0.112).In the control group,compared with the baseline,FMD significantly decreased at 1day after TRI(11.80±3.10% vs.5.99±1.71%,P<0.001)and was still much lower at 3-month follow-up(11.80±3.10% vs.6.81 ± 1.86%,P<0.001).Besides,FMD was obviously higher in nicorandil group than that in control group at 3 months(10.38±2.43% vs.6.81±1.86%,P<0.001)but not 1 day after TRI(5.83±2.26% vs.5.99±1.71%,P=0.668).Compared with NMD at baseline,NMD at 1 day after the procedure was significantly decreased in both the nicorandil group(16.82±5.24% vs.9.46±4.68%,P<0.001)and control group(16.56±5.10% vs.9.81±6.26%,P<0.01).However,at 3 months follow-up,NMD had recovered in the nicorandil group(16.82±5.24% vs.15.94±6.28%,P=0.391)but not in the control group(16.56±5.10% vs.10.46±5.37%,P<0.01)compared with baseline.Moreover,no significant difference was observed in NMD between two groups at 1 day after TRI(9.46±4.68% vs.9.81±6.26%,P=0.721).However,the NMD was much higher in nicorandil group than that in the control group at 3 months(15.94±6.28% vs.10.46±5.37%,P<0.001).Conclusions: Long-term administration of nicorandil after TRI could improve the endothelial function of the cannulated radial artery. |
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