56 D . C . Fitzgerald et al .: J Extra Corpor Technol 2024 , 56 , 55 – 64 Introduction
The practice of cardiopulmonary bypass ( CPB ) has dramatically improved since its advent in the 1950s [ 1 ]. New and emerging data have informed evidence-based clinical guidelines and professional society standards and guidelines that contribute to the advancement of the conduct of CPB [ 2 – 4 ]. Despite these advancements , wide variation persists in the adoption of professional practice standards and / or evidencebased practices [ 5 , 6 ]. Advancements in local quality improvement , research , and health policy benefit from rigorous clinical databases ; yet , existing cardiac surgical registries ( e . g ., The Society of Thoracic Surgeons Adult Cardiac National Database ) lack important detail concerning the practice of CPB to meaningfully evaluate its associated impact on patient safety and outcomes [ 7 ].
Prior work has identified a relationship between the variation in the adoption of evidence-based techniques and technology and morbidity , mortality , and healthcare expenditures [ 8 , 9 ]. Reducing unwarranted variation in CPB practices can be achieved by measuring and benchmarking processes of care against professional standards and evidence-based clinical practice guidelines . The Perfusion Measures and Outcomes ( PERForm ) registry was established in 2010 and is administered through the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative ( MSTCVS-QC ). The PERForm registry seeks to develop and disseminate quarterly benchmarking reports to member hospitals regarding the practice of CPB [ 10 ]. While initially piloted within the state of Michigan , the PERForm registry has expanded to participants across the United States and was recognized in 2017 as the official registry of the American Society of ExtraCorporeal Technology ( AmSECT ).
This first annual PERForm registry report summarizes overall and annual trends in patient characteristics as well as CPBrelated practice patterns among adult ( 18 years of age ) patients undergoing cardiac surgery ( isolated coronary artery bypass grafting , CABG ; isolated valve ; CABG / valve ) between 2019 and 2022 from 42 U . S . participating hospitals . The goal of this report is to advance benchmarking information for the cardiac surgical community , including CPB practices , adherence to evidence-based guidelines and professionally based standards and guidelines , and intraoperative adverse events . Findings derived from this report distinctively advance benchmarking activities relative to other traditional mechanisms and underscore the importance of participating in observational clinical registries for quality assessment and improvement .
Materials and methods
This study was approved by the University of Michigan ’ s IRB ( HUM00164136 , “ Notice of Not Regulated Determination ”, 7 / 24 / 2019 ). Data use agreements restrict the distribution of raw study-related data files . Requests for summary statistics will be reviewed and may be approved by the study team . The centralized IRB governs both the housing and use of all submitted data .
Data used for this study included cardiac surgical operations that required the use of CPB and were performed between
January 1 , 2019 , and December 31 , 2022 . The present report covers the period starting with PERForm version 4 given this update involved a significant change in registry fields . Data elements ( e . g ., extracorporeal circuit characteristics , anemia , blood product utilization , myocardial protection , temperature , aortic disease , medications , safety , and duration indices ) are submitted through a secure web portal to a dedicated data warehouse developed by a certified STS vendor [ 10 , 11 ]. Perfusion data are in turn probabilistically matched with the participating center ’ s Society of Thoracic Surgeons Adult Cardiac Surgery Database ( STS-ACSD ) using a published algorithm to provide a more comprehensive assessment of operative practices and their associated impact on clinical outcomes . Surgical harvest files were also used to ascertain patient characteristics and estimate the patient ’ s preoperative risk of major morbidity and mortality . The occurrence of any of the following ten intraoperative adverse events were reported , including arterial air , oxygenator failure , pump head failure , low venous reservoir level , any electrical failure , gas supply failure , thrombus clot in the circuit , airlock , venous air , and others . While the PERForm registry tracks manufacturer-specific equipment ( including disposables ), this report only covers the manufacturer associated with specific perfusion electronic medical record systems .
Continuous variables are presented as the median ( interquartile range ), while categorical variables are presented as counts and percentages . Comparisons across surgical years ( 2019 – 2022 ) were made using both Pearson ’ s Chi-Square and Fisher ’ s Exact tests for categorical variables , and Student ’ s t-tests and Wilcoxon rank-sum tests for continuous variables . The degree of missingness across variables is reported . A p-value less than 0.05 was considered for all two-tailed significance testing . Statistical analyses were conducted using SAS version 9.4 ( SAS Institute , Cary , NC ), R version 4.3.1 ( R Foundation for Statistical Computing , Vienna , Austria ) and RStudio version 2023.6.2.561 ( Posit Software , PBC , Boston , MA ) [ 11 – 13 ].
Results
A total of 40,777 adult patients underwent cardiac surgery requiring CPB support ( Table 1 ). The percentage of procedures utilizing CPB support did not change over time ( 2019 : 77 %, 2022 : 77 %). The surgical case volume decreased by 13.6 % between 2019 and 2020 ( 10,261 vs . 9295 ). With the addition of 4 contributing hospitals to the Registry , case volume increased 23.6 % between 2021 and 2022 ( 9731 vs . 11,490 ). The median ( IQR ) number of procedures per hospitals was 181.5 ( 121.8 – 277.2 ), a figure that was qualitatively consistent over time . Patients were more commonly male ( 71.6 %), Caucasian ( 80.7 %), and without a history of prior cardiac surgery ( 92.6 %). Major morbidities ( stroke / cerebrovascular accident , surgical re-exploration , deep sternal wound infection , postoperative renal failure ) defined by the STS-ACSD occurred among 34.1 % of patients . The most frequently performed procedure was isolated CABG ( 54.9 %), followed by other ( 22.6 %), isolated valve ( 16.6 %), and CABG / valve ( 7.9 %), Figure 1 . The annual trends in procedure-specific volume are presented in Figure 2 . Additional procedural data using STSreported categorizations are provided in Supplementary Table 1 .