Prognostic impact of dynamic evolution in renal function among patients undergoing elective percutaneous coronary intervention

Background Previous studies have shown that chronic kidney disease(CKD) affected the long-term prognosis of patients underwent the elective percutaneous coronary intervention(EPCI). However, the prognostic impact in patients with the development of the contrast-associated acute kidney injury(CA-AKI) and recovery or progression of CA-AKI were controversial. For the moment, little attention has been paid to the relationship between the dynamic evolution of renal function and its prognosis. Methods We used three stages to characterize the dynamic evolution of renal function, namely the occurrence of CKD at baseline, the occurrence of CA-AKI in the postoperative period and the occurrence of post kindey injury(PKI) at 3 - 6 months postoperatively. Cardiac death and all-cause mortality were used as the endpoint of the study. PKI(+) was defined as CA-AKI not recovered or an increase in absolute serum creatinine (SCr) ≤0.3 mg/dl or a SCr relative increase in creatinine ≤ 50% after 3 - 6 months. PKI(-) was defined as CA-AKI recovered or SCr elevation not meeting the PKI(+) requirement. Results We prospectively enrolled 2951 patients who underwent EPCI from 2012 to 2018. They were divided into three groups according to baseline CKD and CA-AKI: STAGE I[Unimpaired renal function group, CKD(-)/CA-AKI(-) (n=1247)], STAGE II[Partially impaired renal function group, IIa: CKD(-)/CA-AKI(+) (n=91) and IIb: CKD(+)/CA-AKI(-) (n=1472)] and STAGE III[severely impaired renal function group, CKD(+)/CA-AKI(+) (n=141)]. Subsequently, based on the occurrence of PKI, they were divided into six groups: STAGE I/PKI(-) (n=1212), STAGE I/PKI(+) (n=35), STAGE II/PKI(-) (n=1508), STAGE II/PKI(+) (n=55), STAGE III/PKI(-) (n=108), STAGE III/PKI(+) (n=33). In a mean follow-up period of 3.33± 1.39 years, we found that from STAGE I, STAGE II to STAGE III at baseline groups, the incidence of the primary outcome significantly increased. Meanwhile, from the baseline groups to the follow-up groups, the dynamic changes in renal function were observed. At the follow-uo groups, the occurrence of PKI did not affect the prognosis of patients in the STAGE I group(hazard ratio [HR] = 0.94, 95%CI: 0.15–8.11, p = 0.949) and the STAGE III group(hazard ratio [HR] = 1.19, 95%CI: 0.50–2.83 p = 0.689). However, for the STAGE II group (hazard ratio [HR] = 2.65, 95%CI: 1.42–4.94, p = 0.002), the development of PKI would lead to a poor prognosis for patients. Conclusion In patients undergoing EPCI, the occurrence of CKD and CA-AKI affected the long-term prognosis of patients. The prognostic impact of the occurrence of PKI depended on the renal function of patients. In patients with unimpaired renal function or severely impaired renal function, the prognostic impact of PKI was negligible. However, in patients with partially impaired renal function, avoidance of PKI could beneficial for their long-term prognosis. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement 1.National Natural Science Foundation of China General Program(Grant number: 81873495) 2.National Natural Science Foundation of China General Program(Grant number: 82070375) 3.Natural Science Foundation for Distinguished Young Scholars of Fujian Province(Grant number: 2021J06030) 4.National Key Clinical Specialty Construction Project of China (Cardiovascular Medicine 2021). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study followed the Helsinki Declaration principles and ethical approval was granted by the Fujian Provincial Hospital ethics committee (Ethical approval number: K2019-07-011). Written informed consent was obtained from all patients. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Data available on request from the authors The data that support the findings of this study are available from the corresponding author, [Kai-Yang Lin], upon reasonable request.