Chen Jin, Yi Xu, Shubin Qiao, Xinran Tang, Yongjian Wu, Hongbing Yan,Kefei Dou, Bo Xu, Jingang Yang, and Yuejin Yang＊

State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center of Cardiovascular Diseases, Chinese Academy of Medical Sciences &Peking Union Medical College, Beijing 100037, China

TransradialVersusTransfemoral Approach for Percutaneous Coronary Intervention in Elderly Patients in China:A Retrospective Analysis

Chen Jin?, Yi Xu?, Shubin Qiao, Xinran Tang, Yongjian Wu, Hongbing Yan,Kefei Dou, Bo Xu, Jingang Yang, and Yuejin Yang＊

State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center of Cardiovascular Diseases, Chinese Academy of Medical Sciences &Peking Union Medical College, Beijing 100037, China

coronary artery disease; cost-benefit analysis; percutaneous coronary intervention;aged; transradial intervention; transfemoral intervention

ObjectiveTo compare hospital costs and clinical outcomes between transradial intervention (TRI) and transfemoral intervention (TFI) in elderly patients aged over 65 years.

MethodsWe identified 1229 patients aged over 65 years who underwent percutaneous coronary intervention (PCI) in Fuwai Hospital, Beijing, China, between January 1 and December 31, 2010. Total hospital costs and in-hospital outcomes were compared between TRI and TFI. An inverse probability weighting (IPW)model was introduced to control potential biases.

ResultsPatients who underwent TRI were younger, less often female, more likely to receive PCI for single-vessel lesions, and less likely to undergo the procedure for ostial lesions. TRI was associated with a cost saving of CNY7495 (95%CI: CNY4419-10 420). Such differences were mainly driven by lower PCI-related costs. TRI patients had shorter length of stay (1.9 days, 95%CI: 1.1-2.7 days), shorter post-procedural stay (0.7 days, 95%CI: 0.3-1.1 days), and fewer major adverse cardiac events (adjusted odds ratio = 0.47, 95%CI: 0.31-0.73). There was no statistical significance in the incidence of post-PCI bleeding between TRI and TFI (P＞0.05).Such differences remained consistent in clinically relevant subgroups of acute myocardial infarction, acute coronary syndrome, and stable angina.

ConclusionThe use of TRI in patients aged over 65 years was associated with significantly reduced hospital costs and more favorable clinical outcomes.

T RANSRADIAL intervention (TRI) is being increasingly adopted for percutaneous coronary intervention (PCI) due to its potential advantages over transfemoral intervention (TFI). Previous studies have demonstrated fewer access site-related bleeding and vascular complications, shorter length of stay,and better satisfaction in patients undergoing TRI.1-9

Elderly patients with coronary artery disease (CAD) are a growing population who will benefit from PCI. Nevertheless,they are also reported to have a higher risk of access siterelated complications and post-procedural bleeding.10-13So far several studies have evaluated the safety and efficacy of TRI in elderly patients,14-18but none of them have taken the economic consequences into consideration. Using data from the Fuwai PCI database, a single-center registry from the largest heart center in the People’s Republic of China, we sought to compare both hospital costs and clinical outcomes between TRI and TFI in elderly patients aged over 65 years.

PATIENTS AND METHODS

Patients

Our study population consisted of a consecutive cohort of 1490 patients aged over 65 years who underwent PCI between January 1 and December 31, 2010, at Fuwai Hospital,Beijing, China. We excluded patients who underwent ＞1 PCI procedure during hospitalization (n=126), who presented with chronic total occlusion (n=32) or cardiogenic shock(n=5), who were enrolled in other clinical trials (n=31), who underwent a pre-procedural intra-aortic balloon pump (n=21),or who had missing information on cost data (n=46). After these exclusions, our study population consisted of 1229 patients, of whom 1033 (84.1%) had TRI and 196 had TFI.

The institutional review board of Fuwai Hospital, Chinese Academy of Medical Sciences, approved the study and waived the requirement for informed consent.

Hospital costs

The primary outcome was hospital costs, which was defined as the total cost of an in-hospital stay from the day of admission through discharge. All cost data were obtained from the hospital’s accounting system and were further divided into the following categories: PCI-related costs, medication costs, examination costs, transfusion costs, and hospitalization costs inclusive of bed, physician fee, and nursing services.

Clinical outcomes

Since it would be impractical to solely study economic consequences in real-life clinical practice, we also compared clinical outcomes between TRI and TFI. That included post-PCI bleeding events, major adverse cardiac events (MACE),length of stay, and post-procedural stay. Bleeding was defined according to the Bleeding Academic Research Consortium (BARC) definition.19For the purpose of our study, BARC≥2 or ≥3 bleeding were reported. MACE was a composite of death, myocardial infarction, revascularization, and BARC≥3 bleeding during the index hospitalization. Post-PCI bleeding and MACE were validated by medical record review.

Statistical analysis

The distributions of continuous variables were described using mean and standard deviation. Categorical variables were described with frequencies and percentages. Baseline and procedural characteristics were compared using standardized differences, which was calculated as the difference in means or proportions divided by a pooled estimate of the standard deviation.20Unlike traditional significance tests such asttests or chi-square tests, standardized differences are not influenced by sample size and are therefore commonly used to compare the distribution of baseline covariates between treatment groups in propensity score analysis. An absolute standardized difference ＞10 indicates significant imbalance of a covariate.21

Since treatment decisions in real-world practice are often made based on prognostic factors rather than randomization, an inverse probability weighting (IPW) method was introduced to control potential biases. In short, the IPW is an extension of the propensity score method.22-23The propensity score is the probability of exposure to treatment conditional on observed covariates, and it can be used in comparative effectiveness studies to balance covariates across treatment groups. This can be achievedviamatching, stratification, regression adjustment, or IPW. In the present study, we used IPW, because the difference in the sample size between TRI and TFI cohort was disparate,which would limit the number of matched pairs or stratums and thus influence the result of analyses.22-23Moreover,this method has the advantage of allowing adjustment for more confounding factors, and producing less biased estimates to evaluate comparative effectiveness.22By using the IPW method, weights were obtained from a logistic regression model with access approach (TRI or TFI) as the only dependent variable and all other confounding factors as independent variables. Independent variables included age, gender, heart rate, systolic and diastolic blood pressure, prior history of coronary arterial bypass grafting(CABG), PCI, myocardial infarction, stroke, diabetes mellitus, hypertension, hyperlipidemia, clinical diagnosis [ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI), unstable angina, or stable angina], left ventricle ejection fraction(LVEF) before PCI, primary PCI, creatinine concentration before PCI, arterial sheath size, single-, double-, or triplevessel lesion, left main disease, lesion type (de novo, intra stent, or restenosis), lesion location (ostial or bifurcation lesion), number of treated lesion, number of stents used,stent type (drug-eluting stent and/or bare metal stent),and domesticversusimported stents (due to cost differences). Use of intravascular ultrasound (IVUS) was not included in the logistic regression model, since it was used after deciding the access site. Because of their exclusive role in TFIs, vascular closure devices were also not included in the model. Missing continuous variables were replaced with the mean of the variable, and missing categorical variables were imputed with the maximum frequency.

Estimation of TRIversusTFI effect was derived by solving the IPW estimating equations after the weights were obtained. The relationship between TRIversusTFI and study outcomes were then estimated using IPW regression models, including the generalized linear model with log link for cost, length of stay, and post-procedural stay, as well as the logistic regression model for other clinical outcomes. Hospital costs and clinical outcomes were analyzed according to intention-to-treat principle (before the potential crossover). Significance tests and confidence intervals (CI) for estimations were based on robust standard errors. Pre- and post-IPW balances of the covariates between TRI and TFI were assessed using standardized difference. Subgroup analyses were performed in clinically relevant subgroups of acute myocardial infarction [STEMI and NSTEMI], acute coronary syndrome [STEMI, NSTEMI,and unstable angina], and stable angina.

AllPvalues were 2-sided andP＜0.05 was considered statistically significant. All statistical analyses were performed using SAS 9.3 (SAS Institute).

RESULTS

Among 1229 patients aged over 65 years who were eligible for the analysis, there was no crossover from transradial to transfemoral approach.

Baseline and procedural characteristics of TRI and TFI cohorts are shown in Table 1 and 2. Compared with TFI, patientsundergoing TRI were slightly younger (average 71.0vs.71.7 years); less often female (34.9%vs. 50.0%); less likely to have prior history of myocardial infarction,CABG, PCI, stroke, and diabetes mellitus; and more likely to present with STEMI on admission (all standardized differences ＞10).

Table 1.Baseline characteristics of elderly patients undergoing TRI and TFI

A 6-French arterial sheath was used for the majority of patients in both groups. Patients undergoing TRI were more likely to undergo PCI for single-vessel lesions, but less likely to receive the procedure for ostial lesions, or use IVUS during the interventional procedure. The number of treated lesions and the number of stents used, as well as the proportion of domestic to imported stents implanted, were similar between TRI and TFI cohorts. Vascular closure devices (CNY3000,approximately USD455) were used in 71.9% of TFI patients, while all TRI patients used manual compression or a radial compression band that costs less than CNY300 (USD45).

After being adjusted for all observed characteristicsby the propensity score IPW method, all observed characteristics were well balanced between TRI and TFI cohorts (Fig. 1).

Table 2.Procedural characteristics of elderly patients undergoing TRI and TFI

Hospital costs and clinical outcomes of TRI and TFI cohorts are shown in Table 3. The average total hospital costs were CNY59 044 (USD8946) for TRI and CNY68 997(USD10 454) for TFI. After IPW adjustment for all confounders, TRI was associated with a cost saving of CNY7495 (USD1136) (95%CICNY4419-10420). More than 50% of such difference was due to lower PCI-related costs(adjusted difference CNY4067), which was partially driven by the exclusive use of vascular closure devices in TFI.Similarly, the hospitalization costs (adjusted difference CNY1394), medication costs (adjusted difference CNY1360),and examination costs (adjusted difference CNY671) were all significantly lower in TRI patients (P=0.0004,P=0.0007,andP=0.0133, respectively). There was no transfusion cost, since none of the patients received blood transfusion.

The unadjusted rates of MACE were 2.9% for TRI and 5.6% for TFI. After IPW adjustment, TRI patients were less likely to suffer from MACE (adjusted odds ratio 0.47, 95%CI0.31-0.73) than TFI patients during the index hospitalization. There was no statistical significance in the incidence of BARC ≥2 or BARC ≥3 bleeding between TRI and TFI (allP＞0.05). Both the length of stay and post-procedural stay were shorter in TRI cohort(length of stay, 6.7vs. 8.9 days, adjusted difference?1.9 days, 95%CI-2.7 to ?1.1; postprocedural stay,3.6vs. 4.2 days, adjusted difference -0.7 days, adjusted difference ?1.1 to ?0.3).

A total of 199 patients underwent PCI for acute myocardial infarction; 863 underwent PCI for acute coronary syndrome; and 330 underwent PCI for stable angina (Table 4). Subgroup analyses showed similar trends of lower hospital costs, fewer MACE, shorter length of stay, and shorter post-procedural stay with TRI, though not all differences were statistically significant in these clinically relevant subgroups.

Figure 1.Comparisons of baseline and procedural characteristics between transradial and transfemoral intervention groups before and after IPW adjustment.A standardized difference ＞10 indicates significant imbalance between the two groups.MI: myocardial infarction; DES: drug-eluting stent; BMS: bare metal stent; IPW: inverse probability weighting.

Table 3.Comparisons of hospital costs and clinical outcomes between the groups of TRI and TFI

DISCUSSION

In this large retrospective observational study of elderly patients undergoing PCI in China, we found that transradial approach was associated with significantly lower hospital costs, fewer MACE, shorter length of stay,and shorter post-procedural stay. Although TRI was performed more frequently on patients with better prognostic factors and lower risks, such association persisted after accounting for all observed characteristics using the IPW method. Similar trends were observed in clinically relevant subgroups of acute myocardial infarction, acute coronary syndrome, and stable angina. Taken together with previous studies,1-9these results support the current recommendations for adoption of tranradial approach in patients undergoing PCI.24-26

The prevalence of CAD is associated with increasing age. Elderly patients, defined by Mehtaet al27as aged over 65 years, comprised a large proportion of CAD patients who need PCI.28But they are also at high risk of procedural complications and post-procedural bleeding due to longstanding hypertension, peripheral atherosclerosis and other severe pre-procedural comorbidities.10-13Several comparisons have been conducted between TRI and TFI in elderly patients.14-18The present one, based on the propensity score IPW method, showed that the rate of MACE in elderly patients underwent TRI were significantly lower than TFI. Moreover, TRI patients had shorter length of stay and were discharged sooner after undergoing PCI. Similar trends were found in subgroup analyses. These findings provide new evidence to support the efficacy and benefit of TRI in elderly patients.

Bleeding complications have been identified as a strong predicting factor of worse outcomes after PCI.29Several strategies have been suggested to reduce the risk of post-PCI bleeding, including pharmacologic,technological, and procedural approaches.30As one of the procedural approaches, TRI has been shown to reduce bleeding by both observational4,6,9and randomized1,8studies. Different from these results, we found no statistical significance in the incidence of post-PCI bleeding between the 2 treatment groups in the present study. Considering that TRI patients did numerically have fewer post PCI bleeding (BARC ≥2: 7.7%vs. 8.7%,P=0.940; BARC ≥3: 1.2%vs. 3.1%,P=0.051), out limited sample size of study population may be the reason why the results are so distinct.

Table 4.Comparisons of hospital costs and clinical outcomes between the groups of TRI and TFI: subgroup analyses by acute myocardial infarction, acute coronary syndrome, and stable angina

Despite the advantages of transradial approach mentioned above, so far no study has examined the economic impact of TRI in elderly patients. In our previous analysis of TRIvs. TFI in all age groups, we found that TRI was associated with an average cost-saving of CNY8147.9We also found a cost-saving of CNY7474 in women undergoing TRI.31In the present study, which was performed solely in patients aged over 65 years, TRI was associated with lower total hospital costs (cost difference CNY7495).More than 70% of such cost differences was attributed to reduced PCI-related costs (cost difference CNY4067).Since patients in both treatment groups had similar arterial sheath size, number of stents, and utilization of more expensive imported stents, these are unlikely to be thecause of such cost saving. Although IVUS was performed in a greater proportion of TFI patients, its utilization was infrequent (2.2%vs. 5.3%) and was not possible to cause such differences in PCI-related costs either. However,vascular closure devices (CNY3000) were used in 71.9%of TFI patients, costing much more than manual compression or radial compression bands. Therefore, it is likely that the cost difference between TRI and TFI is driven by the differential use of vascular closure devices.In addition, there was also a significant reduction in hospitalization costs (cost difference CNY1394), medication costs (cost difference CNY1360), and examination costs(cost difference CNY671). These differences might be attributable to shorter length of stay, shorter post-procedural stay, as well as lower incidence of MACE in TRI cohort.

Several limitations of this study should be acknowledged. First, it is limited by its non-randomized and retrospective nature, although we used the propensity score IPW method to minimize the baseline disparity. Although all observed characteristics were well-balanced between TRI and TFI cohorts after the introduction of IPW method,there might still be some unmeasured confounders. The disparate difference in the sample size between the two cohorts may also have influenced our results. Second, our study only included data from a single center, in which transradial approach has been adopted for years. Since the learning curve of TRI for operators could affect clinical outcomes, the generalizability of these findings to other centers remains to be established. Third, the evaluation of economic consequences was conducted based on the hospital’s accounting system. The total cost of TRI patients could have been underestimated, if they had undergone more examinations before their admission, since we did not have access to outpatient costs data prior to hospitalization.

Conflict of Interest Statement

The authors have no conflict of interest to disclose.

1. Jolly SS, Yusuf S, Cairns J, Niemel? K, Xavier D, Widimsky P, et al. Radialversusfemoral access for coronary angiography and intervention in patients with acute coronary syndromes (RIVAL): a randomised, parallel group, multicentre trial. Lancet 2011; 377(9775):1409-20. doi:10.1016/S0140-6736(11)60404-2.

2. Yang Y-J, Kandzari DE, Gao Z, Xu B, Chen J-L, Qiao S-B,et al. Transradialversustransfemoral method of percutaneous coronary revascularization for unprotected left main coronary artery disease: comparison of procedural and late-term outcomes. JACC Cardiovasc Interv 2010;3(10):1035-42. doi: 10.1016/j.jcin.2010.09.003.

3. Brueck M, Bandorski D, Kramer W, Wieczorek M, H?ltgen R, Tillmanns H. A randomized comparison of transradialversustransfemoral approach for coronary angiography and angioplasty. JACC Cardiovasc Interv 2009; 2(11):1047-54. doi: 10.1016/j.jcin.2009.07.016.

4. Feldman DN, Swaminathan RV, Kaltenbach LA, Baklanov DV, Kim LK, Wong SC, et al. Adoption of radial access and comparison of outcomes to femoral access in percutaneous coronary intervention an updated report from the National Cardiovascular Data Registry (2007–2012). Circulation 2013; 127(23):2295-306. doi: 10.1161/CIRCULATIONAHA.112.000536.

5. Chase AJ, Fretz EB, Warburton WP, Klinke WP, Carere RG,Pi D, et al. Association of the arterial access site at angioplasty with transfusion and mortality: the MORTAL study(Mortality benefit of reduced transfusion after percutaneous coronary interventionviathe arm or leg). Heart 2008;94(8):1019-25. doi: 10.1136/hrt.2007.136390.

6. Baklanov DV, Kaltenbach LA, Marso SP, Subherwal SS,Feldman DN, Garratt KN, et al. The prevalence and outcomes of transradial percutaneous coronary intervention for ST-segment elevation myocardial infarction: analysis from the National Cardiovascular Data Registry (2007 to 2011). J Am Coll Cardiol 2013; 61(4):420-6. doi:10.1016/j.jacc.2012.10.032.

7. Rao SV, Cohen MG, Kandzari DE, Bertrand OF, Gilchrist IC.The transradial approach to percutaneous coronary intervention: historical perspective, current concepts, and future directions. J Am Coll Cardiol 2010; 55(20):2187-95.doi: 10.1016/j.jacc.2010.01.039.

8. Romagnoli E, Biondi-Zoccai G, Sciahbasi A, Politi L, Rigattieri S, Pendenza G, et al. Radialversusfemoral randomized investigation in ST-segment elevation acute coronary syndrome: the RIFLE-STEACS (RadialVersusFemoral Randomized Investigation in ST-Elevation Acute Coronary Syndrome) study. J Am Coll Cardiol 2012; 60(24):2481-9. doi: 10.1016/j.jacc.2012.06.017.

9. Jin C, Li W, Qiao SB, Yang JG, Wang Y, He PY, et al. Costs and benefits associated with transradialversustransfemoral percutaneous coronary intervention in China. J Am Heart Assoc 2016; 5(4):e002684. doi: 10.1161/JAHA.115.002684.

10. Arnold SV, Alexander KP, Masoudi FA, Ho PM, Xiao L,Spertus JA. The effect of age on functional and mortality outcomes after acute myocardial infarction. J AmGeriatr Soc 2009; 57(2):209-17. doi: 10.1111/j.1532-5415.2008.02106.x.

11. Feldman DN, Gade CL, Slotwiner AJ, Parikh M, Bergman G, Wong SC, et al. Comparison of outcomes of percutaneous coronary interventions in patients of three age groups (＜ 60, 60 to 80, and＞ 80 years) (from the New York State Angioplasty Registry). Am J Cardiol 2006;98(10):1334-9. doi: 10.1016/j.amjcard.2006.06.026.

12. Piper WD, Malenka DJ, Ryan TJ, Shubrooks SJ, T O’Connor G, Robb JF, et al. Predicting vascular complications in percutaneous coronary interventions. Am Heart J 2003;145(6):1022-9. doi: 10.1016/S0002-8703(03)00079-6.

13. Assali AR, Moustapha A, Sdringola S, Salloum J, Awadalla H, Saikia S, et al. The dilemma of success: percutaneous coronary interventions in patients ≥ 75 years of age—successful but associated with higher vascular complications and cardiac mortality. Catheter Cardiovasc Interv 2003;59(2):195-9. doi: 10.1002/ccd.10532.

14. Koutouzis M, Matejka G, Olivecrona G, Grip L, Albertsson P. Radialvs. femoral approach for primary percutaneous coronary intervention in octogenarians. Cardiovasc Revasc Med 2010; 11(2):79-83. doi: 10.1016/j.carrev.2009.04.107.

15. Achenbach S, Ropers D, Kallert L, Turan N, Kr?hner R,Wolf T, et al. Transradialversustransfemoral approach for coronary angiography and intervention in patients above 75 years of age. Catheter Cardiovasc Interv 2008; 72(5):629-35. doi: 10.1002/ccd.21696.

16. Jaffe R, Hong T, Sharieff W, Chisholm RJ, Kutryk MJB,Charron T, et al. Comparison of radialversusfemoral approach for percutaneous coronary interventions in octogenarians. Catheter Cardiovasc Interv 2007; 69(6):815-20. doi: 10.1002/ccd.21021.

17. Yan ZX, Zhou YJ, Zhao YX, Liu YY, Shi DM, Guo YH, et al.Safety and feasibility of transradial approach for primary percutaneous coronary intervention in elderly patients with acute myocardial infarction. Chin Med J (Engl) 2008;121(9):782-6.

18. He PY, Yang YJ, Qiao SB, Xu B, Yao M, Wu YJ, et al. A comparison of transradial and transfemoral approaches for percutaneous coronary intervention in elderly patients based on a propensity score analysis. Angiology 2014;66(5):448-55. doi: 10.1177/0003319714535971.

19. Mehran R, Rao SV, Bhatt DL, Gibson CM, Caixeta A,Eikelboom J, et al. Standardized bleeding definitions for cardiovascular clinical trials a consensus report from the bleeding academic research consortium. Circulation 2011;123(23):2736-47. doi: 10.1161/CIRCULATIONAHA.110.009449.

20. Flury BK, Riedwyl H. Standard distance in univariate and multivariate analysis. Am Stat 1986; 40(3):249-51.

21. Austin PC. Balance diagnostics for comparing the distribution of baseline covariates between treatment groups in propensity-score matched samples. Stat Med 2009;28(25):3083-107. doi: 10.1002/sim.3697.

22. Curtis LH, Hammill BG, Eisenstein EL, Kramer JM, Anstrom KJ. Using inverse probability-weighted estimators in comparative effectiveness analyses with observational databases. Med Care 2007; 45(10):S103-7. doi: 10.1097/MLR.0b013e31806518ac.

23. Austin PC. Optimal caliper widths for propensity-score matching when estimating differences in means and differences in proportions in observational studies. Pharm Stat 2011; 10(2):150-61. doi: 10.1002/pst.433.

24. Windecker S, Kolh P, Alfonso F, Collet J-P, Cremer J, Falk V, et al. 2014 ESC/EACTS Guidelines on myocardial revascularization: the Task Force on Myocardial Revascularization of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS)Developed with the special contribution of the European Association of Percutaneous Cardiovascular Interventions(EAPCI). Eur Heart J 2014; 35(37):2541-619. doi: 10.1093/eurheartj/ehu278.

25. Levine GN, Bates ER, Blankenship JC, Bailey SR, Bittl JA,Cercek B, et al. 2015 ACC/AHA/SCAI focused update on primary percutaneous coronary intervention for patients with ST-elevation myocardial infarction: an update of the 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention and the 2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction: a Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Society for Cardiovascular Angiography and Interventions. Circulation 2016; 133(11):1135-47. doi:10.1161/CIR.0000000000000336.

26. Levine GN, Bates ER, Blankenship JC, Bailey SR, Bittl JA,Cercek B, et al. 2011 ACCF/AHA/SCAI guideline for percutaneous coronary intervention: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Society for Cardiovascular Angiography and Interventions. J Am Coll Cardiol 2011; 58(24):e44-122. doi: 10.1016/j.jacc.2011.08.007.

27. Mehta RH, Rathore SS, Radford MJ, Wang Y, Wang Y,Krumholz HM. Acute myocardial infarction in the elderly:differences by age. J Am Coll Cardiol 2001; 38(3):736-41.

28. Klein LW, Block P, Brindis RG, McKay CR, McCallister BD,Wolk M, et al. Percutaneous coronary interventions in octogenarians in the American College of Cardiology–National Cardiovascular Data Registry: development of anomogram predictive of in-hospital mortality. J Am Coll Cardiol 2002; 40(3):394-402.

29. Doyle BJ, Rihal CS, Gastineau DA, Holmes DR. Bleeding,blood transfusion, and increased mortality after percutaneous coronary intervention: implications for contemporary practice. J Am Coll Cardiol 2009; 53(22):2019-27.doi: 10.1016/j.jacc.2008.12.073.

30. Dauerman HL, Rao SV, Resnic FS,Applegate RJ. Bleeding avoidance strategies: consensus and controversy. J Am Coll Cardiol 2011; 58(1):1-10. doi: 10.1016/j.jacc.2011.02.039.

31. Jin C, Xu Y, Qiao SB, Tang XR, Wu YJ, Yan HB, et al. Comparison of transradial and transfemoral approaches in women undergoing percutaneous coronary intervention in China: a retrospective observational study. Angiology 2017 Jan 1:3319716685670. doi: 10.1177/0003319716685670.

10.24920/J1001-9294.2017.023

for publication December 7, 2017.

?These authors contributed equally to this work.

＊Corresponding author Tel: 86-10-88398760, Fax: 86-10-68331730, E-mail: yangyjfw@126.com