Author + information
- Received March 8, 2017
- Revision received April 6, 2017
- Accepted April 7, 2017
- Published online June 12, 2017.
- Alexander C. Fanaroff, MDa,b,∗ (, )
- Pearl Zakroysky, MSb,
- David Dai, MSb,
- Daniel Wojdyla, PhDb,
- Matthew W. Sherwood, MD, MHSb,d,
- Matthew T. Roe, MD, MHSa,b,
- Tracy Y. Wang, MD, MHS, MSca,b,
- Eric D. Peterson, MD, MPHa,b,
- Hitinder S. Gurm, MDe,
- Mauricio G. Cohen, MDf,
- John C. Messenger, MDg and
- Sunil V. Rao, MDa,b,c
- aDivision of Cardiology, Duke University, Durham, North Carolina
- bDuke Clinical Research Institute, Duke University, Durham, North Carolina
- cDurham Veterans Affairs Medical Center, Durham, North Carolina
- dDivision of Cardiology, Inova Heart and Vascular Institute, Falls Church, Virginia
- eDivision of Cardiology, University of Michigan, Ann Arbor, Michigan
- fCardiovascular Division, University of Miami Miller School of Medicine, Miami, Florida
- gDivision of Cardiology, University of Colorado, Aurora, Colorado
- ↵∗Address for correspondence:
Dr. Alexander C. Fanaroff, Duke Clinical Research Institute, Duke University Medical Center, 2400 Pratt Street, Durham, North Carolina 27705.
Background Professional guidelines have reduced the recommended minimum number to an average of 50 percutaneous coronary intervention (PCI) procedures performed annually by each operator. Operator volume patterns and associated outcomes since this change are unknown.
Objectives The authors describe herein PCI operator procedure volumes; characteristics of low-, intermediate-, and high-volume operators; and the relationship between operator volume and clinical outcomes in a large, contemporary, nationwide sample.
Methods Using data from the National Cardiovascular Data Registry collected between July 1, 2009, and March 31, 2015, we examined operator annual PCI volume. We divided operators into low- (<50 PCIs per year), intermediate- (50 to 100 PCIs per year), and high- (>100 PCIs per year) volume groups, and determined the adjusted association between annual PCI volume and in-hospital outcomes, including mortality.
Results The median annual number of procedures performed per operator was 59; 44% of operators performed <50 PCI procedures per year. Low-volume operators more frequently performed emergency and primary PCI procedures and practiced at hospitals with lower annual PCI volumes. Unadjusted in-hospital mortality was 1.86% for low-volume operators, 1.73% for intermediate-volume operators, and 1.48% for high-volume operators. The adjusted risk of in-hospital mortality was higher for PCI procedures performed by low- and intermediate-volume operators compared with those performed by high-volume operators (adjusted odds ratio: 1.16 for low versus high; adjusted odds ratio: 1.05 for intermediate vs. high volume) as was the risk for new dialysis post PCI. No volume relationship was observed for post-PCI bleeding.
Conclusions Many PCI operators in the United States are performing fewer than the recommended number of PCI procedures annually. Although absolute risk differences are small and may be partially explained by unmeasured differences in case mix between operators, there remains an inverse relationship between PCI operator volume and in-hospital mortality that persisted in risk-adjusted analyses.
For various reasons, percutaneous coronary intervention (PCI) volumes have declined over the past decade, and many operators have observed a corresponding decline in number of procedures performed (1–3). The 2013 American College of Cardiology (ACC)/American Heart Association (AHA)/Society for Cardiovascular Angiography and Intervention (SCAI) clinical competency statement reduced the recommended minimum number of PCI procedures performed annually by each operator from 75 to 50, averaged over 2 years (4,5). Contemporary, nationwide patterns of operator volumes have not been described, and little is known about the characteristics of procedures performed by low-volume operators. Furthermore, while prior studies have examined the volume-outcome relationship (6–10), none have been nationally representative using clinical data or conducted after the change in recommendations. Importantly, operator volume recommendations were based on expert opinion that the increasing safety of PCI minimizes differences in outcomes across operators regardless of the number of procedures they perform, rather than on objective data.
Using data from the nationally representative National Cardiovascular Data Registry (NCDR) CathPCI registry, which collects detailed information on >90% of PCI procedures performed in the United States, we aimed to: 1) assess median operator volumes of PCI procedures; 2) evaluate potential differences in patient and procedural characteristics for high-, intermediate-, and low-volume operators; and 3) determine the relationship between operator volumes and patient outcomes in a large, contemporary sample.
The NCDR CathPCI registry, jointly administered by the ACC and SCAI, has been previously described (11). It collects data from consecutive patients undergoing PCI at >1,500 hospitals in the United States (∼90% of PCI centers), recording information on patient and hospital characteristics, including patient presentation, lesion and procedural details, peri-procedural and discharge medications, and in-hospital outcomes (12). Variables collected are determined and defined by physician work groups; data collection forms and dictionaries are available online from NCDR. Data collected were subject to the NCDR’s comprehensive data quality program, which includes data quality report specifications for capture and transmission, as well as auditing (13).
For this study, we included all PCI procedures entered into CathPCI using version 4 of the data collection form (July 1, 2009, through March 31, 2015); version 4 of the CathPCI data collection form was the first to include the National Provider Identification (NPI) number, which allows for unique identification of the operator for each PCI. We excluded any procedure missing an operator’s NPI number, which was <1% of all PCIs in the database.
Definitions and outcomes
All study definitions were derived from the CathPCI data dictionary. The primary outcome for this analysis was in-hospital mortality, as recorded on the CathPCI data collection form. Secondary outcomes included bleeding events within 72 h of PCI (hemoglobin decrease ≥3 g/dl, transfusion of whole blood or packed red blood cells, or procedural intervention/surgery at the bleeding site), new need for dialysis, PCI success rate, and PCI procedure appropriateness. PCI success was defined as successful dilation of all lesions attempted. Appropriateness was based on the 2012 Appropriate Use Criteria for Coronary Revascularization, and was determined using a validated algorithm (14–16).
The total number of PCI procedures performed or attempted for each operator was counted using each operator’s unique NPI number, and each operator’s average annual volume was calculated by dividing the operator’s total number of PCI procedures by the number of days the operator was active during the study period (date of last PCI procedure − date of first PCI procedure) and multiplying by 365. Because the NPI number is a unique identification carried across hospitals, operator volumes could be counted without regard to where procedures were performed.
As the ACC/AHA/SCAI clinical competence statement recommends that operators perform an average of ≥50 PCIs per year to maintain competence, operators performing <50 PCIs annually were defined as low-volume operators (4). Operators performing 50 to 100 and >100 PCIs per year were defined as intermediate- and high-volume operators, respectively. For a sensitivity analysis, extreme high- and low-volume operators were defined as those performing >413 PCIs (97.5th percentile of the volume distribution) and <26 PCIs (2.5th percentile of the distribution) annually, respectively.
Because the ACC/AHA/SCAI clinical competency statement defines low-volume operators as those performing <50 PCIs annually averaged over a 2-year period, we also examined operator volume trends using this specific definition. We divided the study period into 16 overlapping 8-quarter (2-year) intervals. For each interval, we counted the number of PCIs performed by each operator, then divided by 2 to calculate annual volume averaged >2 years.
The distribution of operator volumes was plotted as a histogram and descriptive statistics were calculated. Median annual operator volumes for states and Dartmouth Atlas of Healthcare hospital referral regions were calculated and plotted on U.S. maps (17). We report the percentage of low-, intermediate-, and high-volume operators (of all operators performing at least 1 PCI during the interval) for each 8-quarter interval.
Patient, procedural, and hospital characteristics are presented for high-, intermediate-, and low-volume operators, with categorical variables presented as frequencies (percentages) and continuous variables presented as medians (interquartile range [IQR]). Pearson chi-square tests and Kruskal-Wallis tests were used for comparing categorical and continuous variables, respectively. A p value threshold of <0.05 was used to define statistical significance. We performed a sensitivity analysis, comparing extreme high- and extreme low-volume operators.
To determine the relationship between operator volume and in-hospital mortality, we created multivariable logistic regression models using the generalized estimating equation method with an exchangeable working correlation structure to account for within-operator and within-center clustering. By accounting for within-center and within-operator clustering, this method accounts for the effect of hospital PCI volume. Covariates for these models were all variables included in the CathPCI in-hospital mortality risk score—age, cardiogenic shock, prior heart failure, peripheral vascular disease, chronic lung disease, estimated glomerular filtration rate (calculated using the Modification of Diet in Renal Disease equation), New York Heart Association functional class, and presentation with ST-segment elevation myocardial infarction (STEMI) (vs. no STEMI)—as well as year of PCI (18). The first model treated operator volume as a continuous variable, and we report the risk-adjusted odds ratio (OR) with associated 95% confidence interval (CI) for a 50-U annual decrease in PCI volume. The second model calculated unadjusted and adjusted ORs with 95% CIs for low- and intermediate-volume operators with high-volume operators as the reference. Regression models were created for the overall dataset and separately for the STEMI subgroup, the primary PCI subgroup (defined as those patients undergoing PCI for STEMI within 12 h of symptom onset), the unstable angina (UA)/non–ST-segment elevation myocardial infarction (NSTEMI) subgroup, and the stable angina subgroup. To examine the effect that potentially modifiable PCI process measures have on the volume-outcome relationship, we calculated the ORs for mortality with 95% CIs for low- and intermediate-volume operators with high-volume operators as the reference after adjusting for all variables included in the CathPCI in-hospital mortality risk score, year of PCI, radial access, drug-eluting stent use, glycoprotein IIb/IIIa inhibitor use, heparin use, and bivalirudin use. As a sensitivity analysis, we calculated adjusted and unadjusted ORs for mortality for extreme low-volume operators with extreme high-volume operators as the reference. We repeated each of these analyses for the secondary outcomes of bleeding complications at 72 h using a validated predictive model for bleeding (19), and new requirement for dialysis using a validated predictive model for post-PCI renal failure (20). For all analyses, an OR <1.00 indicated that lower PCI operator volume was associated with lower odds of the outcome compared with higher operator volume, and an OR >1.00 indicated that lower PCI operator volume was associated with higher odds of the outcome compared with higher operator volume.
To assess the interaction between operator PCI volume, hospital PCI volume, and post-PCI mortality, we computed adjusted and unadjusted ORs for PCIs performed by low-, intermediate-, and high-volume operators at low- (<400 PCIs per year), intermediate- (400 to 800 PCIs per year), and high-volume (>800 PCIs per year) hospitals. For this analysis, PCIs performed by high-volume operators at high-volume centers were the reference; covariates for the adjusted model were the same as those included in the analysis of the association between operator volume and mortality.
All statistical analyses were performed by the Duke Clinical Research Institute using SAS version 9.3 (SAS Institute, Inc., Cary, North Carolina). The Duke University Medical Center Institutional Review Board granted a waiver of informed consent and authorization for this study, as data are collected for CathPCI without individual patient identifiers.
From July 1, 2009, to March 31, 2015, 10,496 operators performed 3,747,866 PCIs at 1,584 sites (Online Figure 1); median annual operator volume was 59 PCIs (IQR: 21 to 106 PCIs). We classified 4,628 operators (44%) who performed <50 PCIs per year as low-volume operators, 3,001 (29%) who performed 50 to 100 PCIs per year as intermediate-volume operators, and 2,867 (27%) who performed >100 PCIs per year as high-volume operators (Figure 1).
When we examined operator volume using the ACC/AHA/SCAI’s definition of total number of PCIs averaged over a 2-year period, findings were similar. For each 8-quarter interval during the study period, the percentage of operators who performed <50 PCIs, 50 to 100 PCIs, and >100 PCIs averaged over 2 years remained stable (Figure 2). Between 43.7% and 44.8% of operators were defined as low-volume operators per the consensus statement recommendation for each 8-quarter interval during the study period. Quarterly operator volumes also remained stable: in the third quarter of 2009, the median operator volume was 17 PCIs; in the first quarter of 2015, the median volume was 18 PCIs (Online Figure 2).
There was regional variability in operator volumes. Throughout the study period, operators in the Western part of the United States had the lowest annual volumes, followed by operators from the South, Midwest, and North. At the state level, median annual operator volumes ranged from a low of 33 in Nevada to a high of 142 in Rhode Island; the total number of operators ranged from 9 in Alaska to 1,197 in California (Online Figure 3). There was also variability by hospital referral region (Figure 3).
All differences between low-, intermediate-, and high-volume operators were nominally statistically significant. Hospital characteristics differed significantly for high-, intermediate-, and low-volume operators; high-volume operators were more likely to practice at an urban or teaching hospital, and practiced at larger hospitals with higher median annual hospital PCI volumes (781 PCIs vs. 509 PCIs vs. 455 PCIs per year for high- versus intermediate- versus low-volume operators, respectively; p < 0.0001) (Table 1).
There were also significant differences in patient characteristics for PCIs performed by low-, intermediate-, and high-volume operators. Patients undergoing PCI by low-volume operators were significantly less likely to have cardiovascular comorbidities than patients undergoing PCI by intermediate- or high-volume operators (Table 1). By contrast, PCIs performed by low-volume operators were more often in patients with STEMI than those performed by intermediate- or high-volume operators (20.7% vs. 19.0% vs. 15.1%; p < 0.0001) and were more often emergency PCIs performed due to concern that ongoing ischemia or infarction could lead to death (22.6% versus 20.7% versus 16.6%; p < 0.001). According to the ACC/SCAI/AHA appropriateness criteria for PCI (16), between 80.0% and 81.6% of PCIs performed by operators at all strata were considered appropriate.
High-volume operators, as compared with intermediate- and low-volume operators, more often attempted PCI on chronic total occlusions and more often attempted 2 or more lesions in 1 lab visit (29% vs. 25.2% vs. 22.5% for high-, intermediate-, and low-volume operators, respectively; p < 0.0001) (Table 2). High-volume operators also more often used radial access than intermediate- or low-volume operators (17.3% vs. 13.0% vs. 7.6%, respectively; p < 0.0001) and less often used bivalirudin and glycoprotein IIb/IIIa inhibitors. For all operator groups, procedure success was >92.5%, although high-volume operators were successful significantly more often than intermediate- and low-volume operators (94.2% vs. 93.3% vs. 92.6%, respectively; p < 0.0001).
The sensitivity analysis comparing extreme low- with extreme high-volume operators showed results consistent with the main findings: Overall, compared with extreme low-volume operators, extreme high-volume operators more frequently performed elective PCI on patients with more medical comorbidities, more often performed complex PCI, and more frequently used radial access (Online Table 1). Differences in procedure characteristics between extreme high- and extreme low-volume operators were numerically greater than those between high- and low-volume operators.
Association between operator volumes and outcomes
Overall, 59,400 patients (1.6%) died while hospitalized. Operator volume, when assessed as a continuous variable, was linearly and inversely associated with in-hospital mortality: for every 50-case decrease in annual PCI volume, there was a corresponding 4% increase in the risk-adjusted odds of in-hospital mortality (OR: 1.04; 95% CI: 1.03 to 1.05). The relationship between operator volume and in-hospital mortality was significant in patients presenting with STEMI (OR: 1.03; 95% CI: 1.02 to 1.04), UA/NSTEMI (OR: 1.04; 95% CI: 1.03 to 1.05), and stable angina (OR: 1.06; 95% CI: 1.02 to 1.11). Risk-adjusted mortality for the subset of STEMI patients undergoing primary PCI was the same as for the full STEMI population.
This relationship was also apparent when examining operator volume as a categorical variable. Unadjusted in-hospital mortality was 1.86% for low-volume operators, 1.73% for intermediate-volume operators, and 1.48% for high-volume operators. After risk adjustment, in-hospital mortality was significantly higher for intermediate- and low-volume operators compared with high-volume operators (OR: 1.16; 95% CI: 1.12 to 1.21 for low- versus high-volume; OR: 1.05; 95% CI: 1.02 to 1.09 for intermediate- vs. high-volume) (Table 3). For low-volume operators, risk-adjusted in-hospital mortality was greater than that of high-volume operators for all presentation subgroups; however, for intermediate-volume operators, risk-adjusted mortality was not significantly greater than that of high-volume operators for the STEMI and stable angina subgroups. When further adjusted for PCI process measures, the relationship between operator volume and mortality was attenuated; in-hospital mortality remained higher for low-volume operators compared with high-volume operators (OR: 1.12; 95% CI: 1.08 to 1.19) but not for intermediate-volume operators (OR: 1.02; 95% CI: 0.99 to 1.05).
The sensitivity analysis comparing in-hospital mortality for extreme low-volume operators with extreme high-volume operators showed results consistent with the comparison between low- and high-volume operators, with slightly greater ORs (Online Table 2).
There was an inverse and linear relationship between operator volume and risk-adjusted new requirement for dialysis (OR: 1.02; 95% CI: 1.01 to 1.03), but no significant association between operator volume and risk-adjusted post-procedure bleeding (OR: 0.99; 95% CI: 0.97 to 1.01). When operator volume was analyzed as a categorical variable, low-volume operators had a higher risk-adjusted rate of new requirement for dialysis compared with high-volume operators, but intermediate-volume operators did not (Online Table 3). Neither low- nor intermediate-volume operators had a higher rate of procedural bleeding compared with high-volume operators. However, in patients with UA/NSTEMI and stable angina, low-volume operators had higher rates of both new requirement for dialysis and procedural bleeding.
Association between hospital volume and mortality by operator volume
For low-, intermediate-, and high-volume operators, adjusted and unadjusted in-hospital mortality was highest at low-volume hospitals and lowest at high-volume hospitals (Table 4). Compared with high-volume operators performing PCI at high-volume hospitals, risk-adjusted in-hospital mortality was 28% higher for low-volume operators performing PCI at low-volume hospitals (OR: 1.28; 95% CI: 1.21 to 1.35), 18% higher for low-volume operators performing PCI at intermediate-volume hospitals (OR: 1.18; 95% CI: 1.10 to 1.25), and 12% higher for low-volume operators performing PCI at high-volume hospitals (OR: 1.12; 95% CI: 1.04 to 1.21). Among intermediate-volume operators, only those performing PCI at low- and intermediate-volume hospitals had significantly greater risk-adjusted mortality than high-volume operators performing PCI at high-volume hospitals.
In this nationally representative study, we found that a large proportion of PCI operators were performing fewer than an average of 50 PCIs annually, the number of procedures recommended by the 2013 ACC/AHA/SCAI clinical competency statement (4). Compared with high- and intermediate-volume operators, low-volume operators performed a greater number of PCIs in an emergency setting, but performed fewer anatomically complex PCIs, treated patients with fewer comorbidities, and less frequently attempted multiple lesions in a single lab visit (Central Illustration). Procedure success and appropriateness rates were high, and similar for high-, intermediate-, and low-volume operators. Absolute differences in mortality were small, but there was an inverse linear association between PCI operator volume and adjusted in-hospital mortality across patient presentations, including emergent procedures for STEMI and elective procedures for stable angina. Among low-volume operators, hospital PCI volume influenced in-hospital mortality; operators practicing at low-volume hospitals had higher mortality than those practicing at high-volume hospitals. These patterns also existed for post-PCI acute kidney injury, but we could not find a volume relationship for post-PCI bleeding.
Despite the ACC/AHA/SCAI’s reduction of the minimum recommended number of annual PCIs to maintain competency to 50 in 2013, many operators do not meet this minimum requirement. In some states, largely concentrated in the less densely populated western part of the country, the median operator volume is <50 PCIs per year. Using clinical and procedural details collected by the CathPCI registry, we found that low-volume operators less often used radial access, and used more contrast dye and minutes of fluoroscopy. Importantly, they also commonly practiced at lower volume hospitals, treated patients with fewer comorbidities but more acute presentations, and attempted less complex lesions than higher-volume operators. Taken together, it appears that these low-volume operators serve an important role by maintaining access to primary PCI for STEMI and performing a disproportionate number of emergency cases. However, the modest increase in the risk of in-hospital mortality, even among STEMI patients, treated by low-volume operators suggests that robust quality improvement processes are necessary to maintain access to primary PCI and improve outcomes.
Seminal studies, published in the late 1990s, showed lower rates of death and cardiovascular events, including need for coronary artery bypass graft surgery, among patients undergoing PCI performed at high-volume centers and by high-volume operators (6,7,21,22). However, the relationship between operator volume and mortality has not been consistently reported in the era of widespread use of coronary stenting. The 2 most contemporary articles analyzing the operator volume-outcome provided important, though conflicting data on this relationship. Moscucci et al. (8), reporting data from PCIs performed in Michigan in 2002, divided operators into quintiles on the basis of annual volume, and found higher rates of major adverse cardiac events (but not death) in patients treated by operators in the bottom 2 quintiles. This study represents the work of a unique collaborative quality improvement initiative with a rigorous quality-controlled, audited database, and does not reflect the national experience. Badheka et al. (10), using data from the Nationwide Inpatient Sample from 2005 to 2009, showed higher risk-adjusted mortality among patients undergoing PCI performed by low- (<16 PCIs per year) compared with high-volume operators (>100 PCIs per year), although overall mortality was low. However, this study was limited by its use of administrative rather than clinical data, and the method used to identify operators might have been less reliable than using NPI number (23). Additionally, data from both studies pre-dated the publication of the COURAGE (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) trial and the 2012 Appropriate Use Criteria for Coronary Revascularization, which may have changed operator volumes (16,24).
By contrast, the CathPCI registry collects detailed patient and procedure data on all PCI procedures performed in ∼90% of U.S. catheterization labs (12), and our analysis included PCIs, regardless of inpatient or outpatient status, with the ability to account for instances in which an individual operator performed PCIs at multiple different hospitals. In that context, our study provides the most comprehensive contemporary examination of operator volumes to date, and adds several important insights.
We showed that there is persistence of the volume-outcome relationship, but as PCI has grown safer with widespread use of coronary stenting and contemporary antithrombotic therapy, the absolute differences in outcomes have attenuated (25). The inverse of the mortality data, which may be thought of as the number of PCIs that would need to be shifted from lower- to higher-volume operators to prevent 1 death, were correspondingly large: 263 for low- versus high-volume operators and 769 for intermediate- versus high-volume operators. Moreover, post-PCI in-hospital mortality increases linearly with decreasing operator volume, without an inflection point to suggest a minimum annual number of PCIs. Despite the recommendations of the consensus competency statement, any volume threshold appears arbitrarily determined, and caution should be exercised when applying specific operator volume recommendations to individual operators. Rather than firm annual volume recommendations, a focus on improving process and outcomes performance measures for PCI across all operators, regardless of volume, might be more appropriate (26). After adjusting for process measures such as radial access and antithrombotic choice, differences in mortality between high-, intermediate-, and low-volume operators were attenuated, suggesting that high-volume operators implement specific strategies that might improve outcomes. Furthermore, some low-volume operators might practice at high-volume centers (although we found that the converse was more likely) and these operators might be able to achieve excellent outcomes because of a “safety net” provided by the structure and processes at that facility (27,28). We found that PCIs performed by low-volume operators practicing at low-volume hospitals were associated with higher mortality than those performed by low-volume operators practicing at intermediate- or high-volume hospitals. As hospitals consolidate and create large health systems, emphasis should be placed on sharing of best practices, consistent protocols, and formalizing processes for transferring the most complex PCIs to high-volume operators.
Another important aspect of our study was the reporting of the volume-outcome relationship by patient presentation. Though there was a significant relationship between operator volume and mortality regardless of how patients presented for PCI, we found that the relationship between operator volume and mortality was weakest in STEMI patients and strongest in patients with stable angina. Rates of new requirement for dialysis and procedural bleeding, potential procedure-related mediators of mortality in patients undergoing PCI, were statistically greater for low-volume operators than high-volume operators only in patients with UA/NSTEMI and stable angina. These findings suggested that operator volume might play a larger role in lower-risk patients, whereas patient factors might partially overwhelm the effect of operator volumes on outcomes in patients with STEMI.
Even though the CathPCI registry collects data from ∼90% of U.S. hospitals, some operators perform PCIs at hospitals that do not participate in CathPCI and their procedures will be undercounted. Most hospitals that do not participate in CathPCI are Veterans Administration (VA) hospitals. Between 2005 and 2014, 801 operators performed diagnostic coronary angiography in the VA system (29); even assuming that all of these operators performed PCIs at both CathPCI and VA hospitals and thus had their volumes undercounted in our study, at least 36% of operators would still be performing fewer than the minimum recommended standard. Additionally, this study was a retrospective analysis, and therefore subject to unmeasured confounding and other biases inherent to post-hoc analysis; it is possible, for example, that high-volume operators performed more PCIs because they were known to be more skilled and receive more referrals, and that increasing low-volume operators’ PCI volumes would not improve outcomes. Moreover, CathPCI does not include variables that could be used to approximate overall experience, such as number of years in practice, total lifetime volume, or board certification, factors that might influence both operator competency and the relationship between annual operator volume and outcomes (4). However, CathPCI collects comprehensive data about comorbidities and procedure characteristics and we adjusted for measured confounders, including hospital PCI volume. Our analysis of more than 3 million PCIs performed by more than 10,000 operators in a national database with strict quality controls provided the best possible description of PCI operator volume patterns and the best evidence to date of the contemporary relationship between volume and outcomes.
Many PCI operators perform an average of <50 PCI procedures annually, the minimum number recommended by the 2013 ACC/AHA/SCAI clinical competency statement. Although absolute risk differences were small, operator volumes were linearly and inversely associated with in-hospital mortality, even in risk-adjusted analyses. Low-volume operators performed a disproportionate number of emergency PCIs and primary PCIs for STEMI, suggesting that they might perform an important role in maintaining access to PCI.
COMPETENCY IN PATIENT CARE AND PROCEDURAL SKILLS: A large proportion of operators in the United States perform fewer than 50 PCI procedures annually, the number recommended by professional societies. Despite the inverse association between volume and mortality for patients undergoing PCI, absolute differences in mortality based on operator volume were small.
TRANSLATIONAL OUTLOOK: Future studies should identify measurable process and outcome variables other than case volume that better correlate with operator competency.
For supplemental tables and figures, please see the online version of this article.
Dr. Fanaroff has received funding from Gilead Science. Dr. Roe has received research funds from Eli Lilly, Sanofi, Daiichi-Sankyo, Janssen Pharmaceuticals, Ferring Pharmaceuticals, Myokardia, and AstraZeneca; and has received consulting fees from PriMed, AstraZeneca, Boehringer Ingelheim, Merck, Actelion, Amgen, Myokardia, Eli Lilly, Novartis, Daiichi-Sankyo, Quest Diagnostics, and Elsevier Publishers. Dr. Wang has received funding from AstraZeneca, Boston Scientific, Bristol-Myers Squibb, Daiichi-Sankyo, Lily USA, Pfizer, Regeneron, and Gilead. Dr. Rao has received consultant fees from Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- American College of Cardiology
- American Heart Association
- National Cardiovascular Data Registry
- National Provider Identification
- non–ST-segment elevation myocardial infarction
- percutaneous coronary intervention
- Society for Cardiovascular Angiography and Intervention
- ST-segment elevation myocardial infarction
- unstable angina
- Received March 8, 2017.
- Revision received April 6, 2017.
- Accepted April 7, 2017.
- 2017 American College of Cardiology Foundation
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