IJCS | Volume 31, Nº6, November / December 2018

567 Lacerda et al. Paradoxical choice for radial access in ACS Int J Cardiovasc Sci. 2018;31(6)562-568 Original Article tends to avoid the radial access as the patient’s condition gets more severe, disregarding patient’s higher risk of bleeding. On the other hand, we should recognize that this is not a conscious choice. The risk-treatment paradox has been described in situations in which the most effective approach is also the most complex. For example, in atrial fibrillation, anticoagulant therapy is more frequently provided to patients with a low risk of embolic events than patients at high risk. 16 In the ACS scenario also, there has been no association between risk and the choice for an invasive strategy. 17,18 In PCI, the prospective, observational, multicenter study by Wimmer et al., 7 also reported this phenomenon by showing that patients at higher risk of femoral access site complications were less susceptible of receiving the radial access approach. An additional contribution of our study is the identification of independent predictors involved in the generation of this paradox. Other previous studies 19,20 evaluated the predictors involved in the choice for the radial access, however, in none of them a multivariate analysis was performed to minimize confounding bias. Once the presence of the risk-treatment paradox is detected in certain situation, a possible adjustment strategy is the use of probabilistic models to estimate the risk. 21,22 In other words, the use of scores for allocation of more complex resources induces the physician to make decisions based on probability. In case of bleeding in ACS, the best validated models are the CRUSADE 8 and the ACUITY scores. 9 Our findings were obtained in a single center, inwhich five interventional cardiologists were working during the study period. Thus, we must recognize the limited external validation of these findings. Nevertheless, the real aimof this studywas not to describe interventionists’ behavior, since in fact it may vary considerably among regions. Actually, the impact of the present study is not the inference of the prevalence of a phenomenon, but rather to call attention to a situation inwhich the decision- making process may suffer a risk-treatment paradox. A natural thought would be to suggest an evaluation of medical practice variation, to verify the uniformity of this phenomenon. However, we avoided this analysis, since in the Registry design, the unit of analysis was the patient who was treated and not the physician himself, whose consent to be observed was not sought. We also believe that individual evaluation of each of the five interventionists involved in the study would not be accurate due to the sample size of the study. Conclusion In this exploratory study, we observed that the choice for the radial access was not primarily influenced by its potential benefit on bleeding prevention, since baseline bleeding risk was negatively associated with this access, characterizing a risk-treatment paradox. Determinants of the preference for the radial access were variables that connote patients’ clinical status/ severity, suggesting that in highly complex patients, the access is primarily chosen for its easiness and not for its antihemorrhagic effect. Author contributions Conception and design of the research: Lacerda YF, Sá NC, Suerdieck JG, Viana MS, Fonseca L, Lopes F, Rabelo MMN, Correia LCL. Acquisition of data: Lacerda YF, Sá NC, Suerdieck JG, Sodré GS. Analysis and interpretation of the data: Lacerda YF, Suerdieck JG, VianaMS, SodréGS, Fonseca L, RabeloMMN, Correia LCL. Statistical analysis: Suerdieck JG, Viana MS, Sodré GS, Fonseca L, Lopes F, Correia LCL. Obtaining financing: Lacerda YF. Writing of the manuscript: Lacerda YF, Suerdieck JG, Fonseca L. Critical revision of themanuscript for intellectual content: Lacerda YF, Sá NC, Lopes F, Rabelo MMN, Correia LCL. Supervision / as the major investigador: Lacerda YF, Sá NC, Rabelo MMN, Correia LCL. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This article is part of the thesis of master submitted by Mateus dos Santos Viana, from Escola Bahiana de Medicina e Saúde Pública. Ethics approval and consent to participate This study was approved by the Ethics Committee of the Hospital São Rafael under the protocol number 35/11. All the procedures in this study were in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study.