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Access or excess? Examining the argument for regionalized cardiac care

2020; Elsevier BV; Volume: 160; Issue: 3 Linguagem: Inglês

10.1016/j.jtcvs.2019.12.125

1097-685X

Tara Karamlou, Douglas R. Johnston, Carl L. Backer, Eric E. Roselli, Karl F. Welke, Christopher A. Caldarone, Lars G. Svensson,

Cardiovascular Issues in Pregnancy

Central MessageRegionalization of cardiac surgical services is supported by the volume–outcomes relationship and may represent a viable solution to optimize value-based care. We examine both sides of the argument for and against a regionalized cardiac surgery system.This Invited Expert Opinion provides a perspective on the following paper: JAMA Surgery. 2016; 151:1001-1002. https://doi.org/10.1001/jamasurg.2016.1059. Regionalization of cardiac surgical services is supported by the volume–outcomes relationship and may represent a viable solution to optimize value-based care. We examine both sides of the argument for and against a regionalized cardiac surgery system. This Invited Expert Opinion provides a perspective on the following paper: JAMA Surgery. 2016; 151:1001-1002. https://doi.org/10.1001/jamasurg.2016.1059. Feature Editor's Note—The Congenital editors of the Journal encourage open, productive discourse on the structure of the system of care in which congenital heart surgery is provided. We therefore welcome the timely, expert opinion by Karamlou and coauthors, who offer an articulate overview on the pros and cons of regionalization of cardiac care. I suspect the authors gave careful consideration to the issues before presenting the final "sort of neutral" conclusion which they capture with Voltaire's "doubt is an uncomfortable position, but certainty is a ridiculous one." However, despite the complexity of the issues, I am confident the authors are not advocates of stifled inactivity. We are a capable specialty, have overcome seemingly insurmountable challenges, and should view this challenge as yet another opportunity. Much like organ transplantation, transcatheter valve replacement, and other advanced therapies, it would seem we could define the standards of a congenital heart center—a version of "regionalization" that emphasizes a patient-first approach. Perhaps it's too alarming, too radical, too simple-minded, or maybe impossible? While Voltaire was no fan of Pascal, I believe Pascal also has words apt to our circumstance: "Set the greatest philosopher in the world on a plank really wider than he needs, but hanging over a precipice, and though reason convince him of his security, imagination will prevail. Many will scarce bear the thought without a cold sweat." The authors have provided our dimension, the size of the plank, the nature of the precipice, and sound reason. What's wrong with a little cold sweat? Rising health care expenditures undoubtedly galvanized early governmental efforts to devise pragmatic cost-containment mechanisms. That the volume–outcomes relationship might be exploited to reduce length of stay for surgical procedures was elucidated by Forrest and colleagues1Forrest W.H. Brown Jr., B.W. Scott W.R. Ewy W. Flood A.B. Impact of Hospital Characteristics on Surgical Outcomes and Length of Stay.1970Google Scholar in their 1970 report to the US Department of Health and Human Services. Since this initial treatise, multiple studies have evaluated the percipience of concentrating highly complex care in high-volume perceived centers of excellence.2Luft H.S. Bunker J.P. Enthoven A.C. Should operations be regionalized? The empirical relation between surgical volume and mortality.N Engl J Med. 1979; 301: 1364-1369Crossref PubMed Scopus (1322) Google Scholar, 3Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Hospital distribution and patient travel patterns for congenital heart surgery in the United States.Ann Thorac Surg. 2019; 107: 574-581Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar, 4Gonzalez A.A. Dimick J.B. Birkmeyer J.D. Ghaferi A.A. Understanding the volume- outcome effect in cardiovascular surgery: the role of failure to rescue.JAMA Surg. 2014; 149: 119-123Crossref PubMed Scopus (163) Google Scholar, 5Chang R.K. Klitzner T.S. Can regionalization decrease the number of deaths for children who undergo cardiac surgery? A theoretical analysis.Pediatrics. 2002; 109: 173-181Crossref PubMed Scopus (143) Google Scholar, 6Pasquali S.K. Dimick J.B. Ohye R.G. Time for a more unified approach to pediatric heath care policy?: the case for congenital heart care.JAMA. 2015; 314: 1689-1690Crossref PubMed Scopus (19) Google Scholar, 7Dimick J.B. Nicholas L.H. Ryan A.M. Thumma J.R. Birkmeyer J.D. Bariatric surgery complications before vs after implementation of a national policy restricting coverage to centers of excellence.JAMA. 2013; 309: 792-799Crossref PubMed Scopus (133) Google Scholar While characterization of an idealized care delivery system for congenital cardiac surgery has been an interest of our investigative group for several years,3Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Hospital distribution and patient travel patterns for congenital heart surgery in the United States.Ann Thorac Surg. 2019; 107: 574-581Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar,8Karamlou T. Jacobs M.L. Pasquali S. He X. Hill K. O'Brien S. et al.Surgeon and center volume influence on outcomes after arterial switch operation: analysis of the STS Congenital Heart Surgery Database.Ann Thorac Surg. 2014; 98: 904-911Abstract Full Text Full Text PDF PubMed Scopus (48) Google Scholar, 9Welke K.F. Diggs B.S. Karamlou T. Ungerleider R.M. The relationship between hospital surgical case volumes and mortality rates in pediatric cardiac surgery: a national sample, 1988-2005.Ann Thorac Surg. 2008; 86: 889-896Abstract Full Text Full Text PDF PubMed Scopus (75) Google Scholar, 10Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Regionalization of congenital heart surgery in the United States.Semin Thorac Cardiovasc Surg. 2020; 32: 128-137Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar, 11Welke K.F. O'Brien S.M. Peterson E.D. Ungerleider R.M. Jacobs M.L. Jacobs J.P. The complex relationship between pediatric cardiac surgical case volumes and mortality rates in a national clinical database.J Thorac Cardiovasc Surg. 2009; 137: 1133-1140Abstract Full Text Full Text PDF PubMed Scopus (152) Google Scholar, 12Karamlou T. McCrindle B.W. Blackstone E.H. Cai S. Jonas R.A. Bradley S.M. et al.Lesion-specific outcomes in neonates undergoing congenital heart surgery are related predominantly to patient and management factors rather than institutional experience: a Congenital Heart Surgeons' Society study.J Thorac Cardiovasc Surg. 2010; 139: 569-577Abstract Full Text Full Text PDF PubMed Scopus (52) Google Scholar the recent article by Goldstone and colleagues13Goldstone A.B. Chiu P. Baiocchi M. Lingala B. Lee J. Rigdon J. et al.Interfacility transfer of Medicare beneficiaries with acute type A aortic dissection and regionalization of care in the United States.Circulation. 2019; 140: 1239-1250Crossref PubMed Scopus (19) Google Scholar on outcomes of regionalized care for adults with type A aortic dissection has provided an important opportunity to explore the wisdom of extending these discussions to the larger population of patients receiving cardiac surgical care. Goldstone and colleagues used the Centers for Medicare and Medicaid Services database over a 5-year period (1999-2014) to identify 16,886 patients with type A aortic dissection. Of this initial population, 8956 patients treated at 3153 unique hospitals were ultimately included after application of the instrumental variables method to ensure more uniform treatment (and transfer) patterns. Primary outcome measures included 30-day mortality and all-cause mortality over a median follow-up of 2.4 years. One unique feature of this study vis-à-vis other papers investigating regionalization is the inclusion of survival beyond hospital discharge. The importance of this metric cannot be overemphasized; if the salutary impact of regionalized care can be extended to improvement in longer-term aggregate productivity (ie, QALYs or the like), regulatory organizations (ie, government and third-party payors) may be incentivized to consider these alternatives. The results of Goldstone and colleagues showed that 52% of patients underwent surgery at a high-volume center (defined as ≥105 total proximal aortic operations), and 40.3% of the patient population was transferred to another facility (either high- or low-volume) for definitive care. As anticipated, patients treated primarily at a high-volume center, and those rerouted to a high-volume hospital, had improved operative survival (relative risk reduction of 8.1%) compared with those treated at a low-volume hospital. Surgical treatment at a high-volume center also translated into a realized mid-term survival benefit. Importantly, mortality was not increased by interfacility transfer and was also insensitive to patients age <65 years. Based on these data, Goldstone and colleagues advocated for regionalization of care by rerouting patients with type A dissection to high-volume facilities. The ideas raised by this article are provocative and mirror similar perspectives in other cardiothoracic subspecialties, including congenital cardiac surgery, thoracic surgery, and other quaternary surgical disciplines.3Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Hospital distribution and patient travel patterns for congenital heart surgery in the United States.Ann Thorac Surg. 2019; 107: 574-581Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar,8Karamlou T. Jacobs M.L. Pasquali S. He X. Hill K. O'Brien S. et al.Surgeon and center volume influence on outcomes after arterial switch operation: analysis of the STS Congenital Heart Surgery Database.Ann Thorac Surg. 2014; 98: 904-911Abstract Full Text Full Text PDF PubMed Scopus (48) Google Scholar, 9Welke K.F. Diggs B.S. Karamlou T. Ungerleider R.M. The relationship between hospital surgical case volumes and mortality rates in pediatric cardiac surgery: a national sample, 1988-2005.Ann Thorac Surg. 2008; 86: 889-896Abstract Full Text Full Text PDF PubMed Scopus (75) Google Scholar, 10Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Regionalization of congenital heart surgery in the United States.Semin Thorac Cardiovasc Surg. 2020; 32: 128-137Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar, 11Welke K.F. O'Brien S.M. Peterson E.D. Ungerleider R.M. Jacobs M.L. Jacobs J.P. The complex relationship between pediatric cardiac surgical case volumes and mortality rates in a national clinical database.J Thorac Cardiovasc Surg. 2009; 137: 1133-1140Abstract Full Text Full Text PDF PubMed Scopus (152) Google Scholar, 12Karamlou T. McCrindle B.W. Blackstone E.H. Cai S. Jonas R.A. Bradley S.M. et al.Lesion-specific outcomes in neonates undergoing congenital heart surgery are related predominantly to patient and management factors rather than institutional experience: a Congenital Heart Surgeons' Society study.J Thorac Cardiovasc Surg. 2010; 139: 569-577Abstract Full Text Full Text PDF PubMed Scopus (52) Google Scholar,14Patti M.G. Corvera C.U. Glasgow R.E. Way L.W. A hospital's annual rate of esophagectomy influences the operative mortality rate.J Gastointest Surg. 1998; 2: 186-192Crossref PubMed Scopus (226) Google Scholar, 15Schlottmann F. Strassle P.D. Charles A.G. Patti M.G. Esophageal cancer surgery: spontaneous centralization in the US contributed to reduce mortality without causing health disparities.Ann Surg Oncol. 2018; 25: 1580-1587Crossref PubMed Scopus (26) Google Scholar, 16Brescia A.A. Syrjamaki J.D. Regenbogen S.E. Paone G. Pruitt A.L. Shannon F.L. et al.Transcatheter versus surgical aortic valve replacement episode payments and relationship to case volume.Ann Thorac Surg. 2018; 106: 1735-1741Abstract Full Text Full Text PDF PubMed Scopus (10) Google Scholar, 17Patel H.J. Herbert M.A. Drake D.H. Hanson E.C. Theurer P.F. Bell G.F. et al.Aortic valve replacement: using a statewide cardiac surgical database identifies a procedural volume hinge point.Ann Thorac Surg. 2013; 96 (discussion: 1565-6): 1560-1565Abstract Full Text Full Text PDF PubMed Scopus (51) Google Scholar, 18Bakaeen F.G. Roselli E.E. Johnston D.R. Soltesz E.G. Tong M.Z. Svensson L.G. Thoracoabdominal aortic aneurysm repair: big case, big risk, big center!.J Surg Res. 2016; 206: I-IIAbstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar Moreover, surgical case volume per se has also been studied as a primary driver for accelerated deployment of alternative innovative techniques, such as transcatheter aortic valve placement, in which surgical aortic valve replacement volume criteria of 50 cases/year were required. While we should not devolve this analysis into the simple equation that a positive volume–outcome relationship is sufficient to advocate for regionalization, it is instructive to triage the nuances by examining related data. In a seminal paper from 1995, Grumbach and colleagues19Grumbach K. Anderson G.M. Luft H.S. Roos L.L. Brook R. Regionalization of cardiac surgery in the United States and Canada. Geographic access, choice, and outcomes.JAMA. 1995; 274: 1282-1288Crossref PubMed Scopus (186) Google Scholar determined that a regionalized system for coronary artery bypass grafting (CABG) surgery in California, similar to those in New York State and Canada, would decrease mortality without reducing access. One may argue that the single-payor system in Canada may negate the validity of this parallel, but the data presented were compelling. The shape of the relationship between improved outcome and repetition in CABG was further elucidated by Banta and Bos,20Banta D. Bos M. The relation between quantity and quality with coronary artery bypass graft (CABG) surgery.Health Policy. 1991; 18: 1-10Crossref PubMed Scopus (21) Google Scholar who found that survival continued to improve even at relatively high hospital and surgeon annual case volumes: 650 and 116, respectively. Defining thresholds where curves may plateau is difficult given the dearth of very high-volume hospitals and surgeons. Whether there is an upper volume limit beyond which mortality rates may increase in high-volume centers secondary to growth outpacing resources remains an unanswered question. In our series of studies on congenital cardiac surgery programs, we could not find evidence to support a volume above which quality was negatively affected.3Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Hospital distribution and patient travel patterns for congenital heart surgery in the United States.Ann Thorac Surg. 2019; 107: 574-581Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar,10Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Regionalization of congenital heart surgery in the United States.Semin Thorac Cardiovasc Surg. 2020; 32: 128-137Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar Data from large-volume aortic and aortic valve centers such as the Cleveland Clinic, in which morbidity and mortality continue to be exceedingly low despite yearly increases in case volume, would suggest that economies of scale expand appropriately with equally scaled programmatic commitment to quality and patient safety within a single institution.18Bakaeen F.G. Roselli E.E. Johnston D.R. Soltesz E.G. Tong M.Z. Svensson L.G. Thoracoabdominal aortic aneurysm repair: big case, big risk, big center!.J Surg Res. 2016; 206: I-IIAbstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar,21Idrees J.J. Schlitz N.K. Johnston D.R. Mick S. Smedira N.G. Sabik III, J.F. et al.Trends, predictors, and outcomes of stroke after surgical aortic valve replacement in the United States.Ann Thorac Surg. 2016; 101: 927-935Abstract Full Text Full Text PDF PubMed Scopus (16) Google Scholar The potential benefits of a regionalized system of congenital cardiac care have been recognized by several countries. Consolidation of CHS in Sweden from 4 hospitals to 2 with the best survival was temporally associated with a decrease in the national mortality rate from 9.5% to 1.9%.22Lundström N.R. Bergen H. Björkhem G. Jögi P. Sunnegârdh J. Centralization of pediatric heart surgery in Sweden.Pediatr Cardiol. 2000; 21: 353-357Crossref PubMed Scopus (117) Google Scholar Similarly, the National Health Service of the United Kingdom proposed a reduction in the number of hospitals performing CHS from 11 to either 6 or 7 and recommended that each center perform at least 500 cases divided by 4 surgeons to maintain competency.23National Health Services (NHS) Specialist ServicesSafe and sustainable: review of children's congenital cardiac services in England pre-consultation business case.http://www.chfed.org.uk/wp-content/uploads/2012/06/Safe_and_Sustainable_Review_of_Childrens_Congenital_Cardiac_Services_in_England_Pre_Consultation_Business_Case.pdfDate: 2011Google Scholar Interestingly, the centralization of care to only 2 centers in Sweden necessitated a major restructuring of pediatric cardiology and educational programs which, ironically, increased collaboration and communication among the local centers and reciprocally with the remaining 2 surgical centers.22Lundström N.R. Bergen H. Björkhem G. Jögi P. Sunnegârdh J. Centralization of pediatric heart surgery in Sweden.Pediatr Cardiol. 2000; 21: 353-357Crossref PubMed Scopus (117) Google Scholar Both Sweden and the UK have also leveraged regionalization to reduce variation in clinical practice, a phenomenon which is widely believed to lead to adverse clinical outcome and higher cost.24Chung S.C. Sundström J. Gale C.P. James S. Deanfield J. Wallentin L. et al.Comparison of hospital variation in acute myocardial infarction care and outcome between Sweden and United Kingdom: population-based cohort study using nationwide clinical registries.BMJ. 2015; 351: h3913Crossref PubMed Scopus (66) Google Scholar,25McHugh K.E. Pasquali S.K. Hall M.A. Scheurer M.A. Cost variation across centers for the Norwood operation.Ann Thorac Surg. 2018; 105: 851-856Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar Alignment between real-world practice and consensus-based guidelines can be improved by a regionalized system of cardiac care. Whether equivalent or superior adherence to empiric best practices can be achieved and sustained by alternative voluntary methods remains unclear. Beyond the assessment of volume-outcome relationships or the applicability of this analogy to regionalizing care, is there meaningful evidence that a regionalized system would represent an improvement over the current system? Heart and lung transplantation is a clear example of the success of coordinated, national deployment of regionalized care. Accreditation by organizations such as the Adult Congenital Heart Association for comprehensive care centers for adult congenital heart disease is another excellent example of a rational process to regionalize high-quality care. Clustering of US hospitals performing aortic surgery, many of which are low-volume centers located near high-volume centers, was apparent in Figure 4 of the Goldstone article.13Goldstone A.B. Chiu P. Baiocchi M. Lingala B. Lee J. Rigdon J. et al.Interfacility transfer of Medicare beneficiaries with acute type A aortic dissection and regionalization of care in the United States.Circulation. 2019; 140: 1239-1250Crossref PubMed Scopus (19) Google Scholar Data from the initial report from our group that characterized the geographic distribution of CHS centers in the United States, were nearly identical.3Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Hospital distribution and patient travel patterns for congenital heart surgery in the United States.Ann Thorac Surg. 2019; 107: 574-581Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar In our study, 101 of 153 existing centers (66%) were located within 25 miles of one another—a system that is inherently redundant and inefficient.3Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Hospital distribution and patient travel patterns for congenital heart surgery in the United States.Ann Thorac Surg. 2019; 107: 574-581Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar Further, similar to the Goldstone article13Goldstone A.B. Chiu P. Baiocchi M. Lingala B. Lee J. Rigdon J. et al.Interfacility transfer of Medicare beneficiaries with acute type A aortic dissection and regionalization of care in the United States.Circulation. 2019; 140: 1239-1250Crossref PubMed Scopus (19) Google Scholar in which interfacility transfer patterns were often consistent among hospitals, we demonstrated that regionalization already occurs in congenital heart surgery (CHS) centers, with the majority of patients bypassing their nearest hospital and 25% traveling more than 100 miles.3Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Hospital distribution and patient travel patterns for congenital heart surgery in the United States.Ann Thorac Surg. 2019; 107: 574-581Abstract Full Text Full Text PDF PubMed Scopus (18) Google Scholar Importantly, many patients traveling long distances do so for relatively simple, elective procedures, such as closure of ventricular septal defect, in which there is unlikely to be meaningful mortality differential among CHS centers. Our subsequent report explored whether regionalization of CHS centers would decrease in-hospital mortality without prohibitive increases in travel distance using simulations whereby patients were redistributed to successively higher-volume-quintile hospitals.10Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Regionalization of congenital heart surgery in the United States.Semin Thorac Cardiovasc Surg. 2020; 32: 128-137Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar This idealized system was derived by modeling regionalization simulation algorithms based on case complexity or empiric volume thresholds. An unexpected finding was that redistributing all patients to high-volume centers reduced mortality by 17% (116 potential lives saved), eclipsing the minimal 1.2% mortality reduction gained by redistributing only patients in the higher-complexity categories.10Welke K.F. Pasquali S.K. Lin P. Backer C.L. Overman D.M. Romano J.C. et al.Regionalization of congenital heart surgery in the United States.Semin Thorac Cardiovasc Surg. 2020; 32: 128-137Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar Travel distance to the resulting 37 hospitals was modestly increased by approximately 40 miles. These data would suggest that optimum regionalization efforts should be extended to all patients with congenital heart disease regardless of complexity. Distillation of the decision algorithm for patient triage to an "all-or-none" dichotomy in lieu of an algorithm based on complexity could be beneficial, given the significant limitations of current risk stratification models. National regionalization would mean consolidation of many centers into fewer centers rather than continued expansion of a high-performing center, which may have adverse consequences for global value-based care. A successful regionalized model must be built with the potential negative consequences of consolidation in mind, including the possibility of antitrust action. While antitrust legislation is generally enforced in business markets other than health care where there is implicit horizontal versus vertical restraint, several highly publicized hospital mergers have been blocked by the Federal Trade Commission.26Balan D.J. Hospital mergers that don't happen.N Engl J Med Catalyst. October 24, 2016; Google Scholar The theoretical concerns about centralized care were voiced by Paul Levy, CEO of the Beth Israel Deaconess Medical Center in his statement equating ever-expanding hospital systems with financial organizations responsible for the financial crisis in 2008: "Organizations deemed 'too big to fail' pose a risk in any industry. In health care, systems may grow so large that they technically survive, but fail in other aspects of patient care."27Levy P. The dangers of too-big-to-fail.http://www.beckershospitalreview.com/hospital-management-administration/the-dangers-of-qtoo-big-to-failq-hospital-systems.htmlDate accessed: February 28, 2020Google Scholar If cardiac surgery regionalization initiatives are to succeed in the goal toward optimizing the patients' longitudinal experience, we may collectively need objective, comprehensive data—or at least more than a nod toward the clichéd notion that "practice makes perfect." Nonetheless, the hard endpoint of improved survival associated with regionalization is difficult to argue against. In congenital cardiac surgery, accurate assessment of the potential benefits, and ultimate success, of regionalization is especially challenging owing to procedural and anatomic heterogeneity, low numbers of high-complexity procedures, and relatively obtuse performance metrics. While it may be true that low-volume centers have suboptimal outcomes, expected mortality metrics are not sufficiently sensitive to measure risk differentials among the spectrum of centers. Welke and colleagues28Welke K.F. Karamlou T. Ungerleider R.M. Diggs B.S. Mortality rate is not a valid indicator of quality differences between pediatric cardiac surgical programs.Ann Thorac Surg. 2010; 89 (discussion: 145-6): 139-144Abstract Full Text Full Text PDF PubMed Scopus (48) Google Scholar elegantly demonstrated the improbability of studying this phenomenon with the current distribution of centers and mortality rates. They found that the minimum annual case volume (or power) to detect meaningful mortality differences among congenital cardiac surgery centers (N = 525) was achieved by only 1.6% (n = 4) of hospitals. For the least-complex cases, nearly 3000 cases would be required, clearly not an achievable mark. Thoracic surgical volume–outcome relationships are similarly difficult to define because of heterogeneity and small volumes at many centers.14Patti M.G. Corvera C.U. Glasgow R.E. Way L.W. A hospital's annual rate of esophagectomy influences the operative mortality rate.J Gastointest Surg. 1998; 2: 186-192Crossref PubMed Scopus (226) Google Scholar,15Schlottmann F. Strassle P.D. Charles A.G. Patti M.G. Esophageal cancer surgery: spontaneous centralization in the US contributed to reduce mortality without causing health disparities.Ann Surg Oncol. 2018; 25: 1580-1587Crossref PubMed Scopus (26) Google Scholar Finally, a link between superior surgical performance and repetition may be an absolute in the early period in which the learning curve is operational; however, this link may be much less important in the later stages, when one's skill set is established—suggesting a metric for surgeon and program experience. Stability may be a necessary adjunct to volume. Similarly, highly evolved cardiac surgery centers may treat a disproportionate number of high complexity or high-risk cases than smaller centers, obfuscating the ability to fairly compare outcomes across centers. Much better and more consistent risk adjustment data is needed, and the current American Association of Thoracic Surgery database initiative may provide some solutions. Explainable artificial intelligence, deep learning with convolutional neural networks, and other types of machine learning constructs may also contribute substantially to our comprehension and measurement of complexity, such that providers can recognize a case that should be regionalized. Regionalization may reduce access to specialized health care services, particularly among disadvantaged sociodemographic groups. Comparably worse outcomes among African Americans and those in lower income quartiles are consistently reported following both congenital and acquired cardiac surgery.29Karamlou T. Peyvandi S. Federman M. Goff D. Murthy R. Kumar S.R. et al.Resolving the Fontan paradox: addressing socioeconomic and racial disparities in patients with a single ventricle.J Thorac Cardiovasc Surg. 2018; 155: 1727-1731Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar,30Lane-Fall M.B. Fleisher L.A. Untangling the web of health care access and racial disparities after coronary artery bypass grafting.J Cardiothorac Vasc Anesth. 2019; 33: 1899-1900Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar Benavidez and colleagues31Benavidez O.J. Gavreau K. Jenkins K.J. Racial and ethnic disparities in mortality following congenital heart surgery.Pediatr Cardiol. 2006; 27: 321-328Crossref PubMed Scopus (51) Google Scholar investigated race/ethnic disparities in outcomes following congenital heart surgery using the Kids Inpatient Database 2000. In this study, in-patient mortality was significantly increased in the black population compared with white ethnicity and regional geographic differences in racial/ethnic outcomes were apparent. In the Benavidez study, socioeconomic status was not associated with increased risk of death, but as Karamlou and colleagues29Karamlou T. Peyvandi S. Federman M. Goff D. Murthy R. Kumar S.R. et al.Resolving the Fontan paradox: addressing socioeconomic and racial disparities in patients with a single ventricle.J Thorac Cardiovasc Surg. 2018; 155: 1727-1731Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar discussed, studies of sociodemographic influence are often superficial (usually as a result of nongranular variable capture in most available datasets) and incompletely assess interactions among highly collinear or modifying factors. Building on this contention, we recently used the Pediatric Health Information Systems database to explore whether inflection points could be determined whereby race/ethnicity could be mitigated by positive modifiers, including discrete income level or more evolved programmatic/process factors on the one hand, or exacerb