Patterns and predictors of stress testing modality after percutaneous coronary stenting: data from the NCDR(®)

Patient Symptoms and Stress Testing After Elective Percutaneous Coronary Intervention in the Veterans Affairs Health Care System

IMPORTANCE

Up to 60% of patients in the US receive a stress test within 2 years of percutaneous coronary intervention (PCI), prompting concerns about the possible overuse of stress testing.

OBJECTIVE

To examine the proportion of patients who underwent stress testing within 2 years of elective PCI, proportion of patients who had symptoms that were consistent with coronary artery disease (CAD), timing of stress testing, and site-level variation in stress testing among symptomatic and asymptomatic patients.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used administrative claims data and clinical records from the US Department of Veterans Affairs (VA) Clinical Assessment, Reporting, and Tracking program. Patients who underwent stress testing within 2 years of elective PCI for stable CAD between November 1, 2013, and October 31, 2015, at 64 VA facilities were included in the analysis. Patients who received stress testing for staging purposes, cardiac rehabilitation evaluation, or preoperative testing before high-risk surgery were excluded. Data were analyzed from June to December 2020.

MAIN OUTCOMES AND MEASURES

The main outcome was the proportion of patients who underwent stress testing and had symptoms that were consistent with obstructive CAD, using definitions from the 2013 clinical practice guideline (Multimodality Appropriate Use Criteria for the Detection and Risk Assessment of Stable Ischemic Heart Disease). Secondary outcomes were the timing of stress testing (assessed using a cumulative incidence curve) and site-level variation in stress testing (assessed using multilevel logistic regression models).

RESULTS

A total of 3705 consecutive patients (mean [SD] age 66.3 [7.6] years; 3656 men [98.7%]; 437 Black individuals [11.8%], 3175 White individuals [85.7%], and 93 individuals [2.5%] of other races and ethnicities [Asian, Hispanic or Latinx, or unknown]) had elective PCI. Of these patients, 916 (24.7%) received a stress test within 2 years, among whom 730 (79.7%) had symptoms that were consistent with obstructive CAD at the time of stress testing. Visual inspection of a cumulative incidence curve for stress testing showed no rapid increases in stress testing at 6 months or 1 year after PCI, which might coincide with routine clinical visits. The proportion of symptomatic patients who underwent stress testing at each VA site ranged from 67.7% to 100%, with no significant site-level variation in stress testing.

CONCLUSIONS AND RELEVANCE

Results of this study suggest that most veterans who underwent stress testing within 2 years after elective PCI had symptoms that were consistent with obstructive CAD. Therefore, measuring low-value stress testing using only administrative claims data may overestimate its prevalence, and concerns about overuse of post-PCI stress testing may be overstated.

Phase analysis single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) detects dyssynchrony in myocardial scar and increases specificity of MPI

BACKGROUND

Myocardial perfusion imaging (MPI) with single-photon emission computed tomography (SPECT) is commonly used to assess patients with cardiovascular disease. However, in certain scenarios, it may have limited specificity in the identification of hemodynamically significant coronary artery disease (e.g., false positive), potentially resulting in additional unnecessary testing and treatment. Phase analysis (PA) is an emerging, highly reproducible quantitative technology that can differentiate normal myocardial activation (synchrony) from myocardial scar (dyssynchrony). The objective of this study is to determine if PA can improve the specificity SPECT MPI.

METHODS

An initial cohort of 340 patients (derivation cohort), referred for SPECT-MPI, was prospectively enrolled. Resting MPI studies were assessed for resting perfusion defects (scar). These were utilized as the reference standard for scar. Subsequently, we collected a second independent validation cohort of 138 patients and tested the potential of PA to reclassify patients for the diagnosis of "scar" or "no scar." Patients were assigned to three categories depending upon their pre-test probability of scar based on multiple clinical and imaging parameters: ≤ 10% (no scar), 11-74% (indeterminate), and ≥ 75% (scar). The ability of PA variables to reclassify patients with scar to a higher group and those without scar to a lower group was then determined using the net reclassification index (NRI).

RESULTS

Entropy (≥ 59%) was independently associated with scar in both patient cohorts with an odds ratio greater than five. Furthermore, when added to multiple clinical/imaging variables, the use of entropy significantly improved the area under the curve for assessment of scar (0.67 vs. 0.59, p = 0.04). The use of entropy correctly reclassified 24% of patients without scar, by clinical model, to a lower risk category (as determined by pre-test probability) with an overall NRI of 18% in this validation cohort.

DISCUSSION

The use of PA entropy can improve the specificity of SPECT MPI and may serve as a useful adjunctive tool to the interpreting physician. The current study determined the optimal PA parameters to detect scar (derivation cohort) and applied these parameters to a second, independent, patient group and noted that entropy (≥ 59%) was independently associated with scar in both patient cohorts. Therefore, PA, which requires no additional imaging time or radiation, enhances the diagnostic capabilities of SPECT MPI.

CONCLUSION

The use of PA entropy significantly improved the specificity of SPECT MPI and could influence the labeling of a patient as having or not having myocardial scar and thereby may influence not only diagnostic reporting but also potentially prognostic determination and therapeutic decision-making.

Clinical Outcomes After Cardiac Stress Testing Among US Patients Younger Than 65 Years

Background

Scientific statements have championed the measurement of clinical outcomes after cardiac stress testing to better define their value. Using contemporary national data, we sought to describe the characteristics of patients who experience outcomes after stress testing.

Methods and Results

Using administrative claims from a large national private insurer, we conducted an observational cohort study of patients without cardiovascular disease aged 25 to 64 years who underwent stress testing from 2006 to 2011 and had at least 1 year of membership in the insurance company before and after testing. We used Kaplan–Meier time‐to‐event analyses to determine rates of acute myocardial infarction (AMI), elective coronary revascularization, and coronary angiography without revascularization in the year following testing. We used logistic regression to determine factors associated with outcomes, and stratified the cohort into quintiles based on likelihood of experiencing AMI and/or revascularization to describe the characteristics of patients at highest and lowest risk. Among 553 027 patients who underwent stress testing (mean age 50 years, 49% women, 73% white), 0.8% were hospitalized for AMI, 1.8% underwent elective coronary revascularization, and 2.5% underwent coronary angiography without revascularization within 1 year. Patients who were older, male, and white were more likely to undergo subsequent revascularization. Patients in the lowest likelihood quintile were young (mean age 40 years), frequently women (84.7%), had a low incidence of coexisting conditions (5.2% with diabetes mellitus), and had a 0.5% rate of AMI and/or revascularization.

Conclusions

The proportion of US patients younger than 65 who had AMI and/or coronary revascularization after stress testing was low. Assessing risk of subsequent outcomes may be useful in improving patient referrals for stress testing.

Variation in Management of Patients With Obstructive Coronary Artery Disease: Insights From the Veterans Affairs Clinical Assessment and Reporting Tool (VA CART) Program

BACKGROUND

Little is known about facility-level variation in the use of revascularization procedures for the management of stable obstructive coronary artery disease. Furthermore, it is unknown if variation in the use of coronary revascularization is associated with use of other cardiovascular procedures.

METHODS AND RESULTS

We evaluated all elective coronary angiograms performed in the Veterans Affairs system between September 1, 2007, and December 31, 2011, using the Clinical Assessment and Reporting Tool and identified patients with obstructive coronary artery disease. Patients were considered managed with revascularization if they received percutaneous coronary intervention (PCI) or coronary artery bypass grafting within 30 days of diagnosis. We calculated risk-adjusted facility-level rates of overall revascularization, PCI, and coronary artery bypass grafting. In addition, we determined the association between facility-level rates of revascularization and post-PCI stress testing. Among 15 650 patients at 51 Veterans Affairs sites who met inclusion criteria, the median rate of revascularization was 59.6% (interquartile range, 55.7%-66.7%). Across all facilities, risk-adjusted rates of overall revascularization varied from 41.5% to 88.1%, rate of PCI varied from 23.2% to 80.6%, and rate of coronary artery bypass graftingvariedfrom 7.5% to 36.5%. Of 6179 patients who underwent elective PCI, the median rate of stress testing in the 2 years after PCI was 33.7% (interquartile range, 30.7%-47.1%). There was no evidence of correlation between facility-level rate of revascularization and follow-up stress testing.

CONCLUSIONS

Within the Veterans Affairs system, we observed large facility-level variation in rates of revascularization for obstructive coronary artery disease, with variation driven primarily by PCI. There was no association between facility-level use of revascularization and follow-up stress testing, suggesting use rates are specific to a particular procedure and not a marker of overall facility-level use.

Variation in use of echocardiography among veterans who use the Veterans Health Administration vs Medicare

BACKGROUND

Rapid growth in the provision of cardiac imaging tests has led to concerns about overuse. Little is known about the degree to which health care delivery system characteristics influence use and variation in echocardiography.

METHODS

We analyzed administrative claims of veterans with heart failure older than 65 years from 2007 to 2010 across 34 metropolitan service areas (MSAs). We compared overall rates and geographic variation in use of transthoracic echocardiography (TTE) between veterans who used the Veterans Health Administration (VA) and propensity-matched veterans who used Medicare. "Dual users" were excluded.

RESULTS

There were no significant differences in clinical characteristics or mortality between the propensity-matched cohorts (overall n = 30,404 veterans, mean age 76 years, mortality rate 52%). The Medicare cohort had a significantly higher overall rate of TTE use compared with the VA cohort (1.25 vs 0.38 TTEs per person-year, incidence rate ratio 2.89 [95% CI 2.80-3.00], both P < .001), but a similar coefficient of variation across MSAs (0.36 [95% CI 0.27-0.45] vs 0.48 [95% CI 0.37-0.59]). There was a moderate to strong correlation in variation at the MSA level between cohorts (Spearman r = 0.58, P < .001).

CONCLUSION

Overall rates of TTE use were significantly higher in a Medicare cohort compared with a propensity score-matched VA cohort of veterans with heart failure living in urban areas, with similar relative degrees of geographic variation and moderate to strong regional correlation. Rates of TTE use may be strongly influenced by health care system characteristics, but local practice styles influence echocardiography rates irrespective of health system.

Stress Testing After Percutaneous Coronary Intervention in the Veterans Affairs HealthCare System: Insights from the Veterans Affairs Clinical Assessment, Reporting, and Tracking Program

BACKGROUND

Stress testing after percutaneous coronary intervention (PCI) in fee-for-service settings is common and rates vary by hospital. Rates of stress testing after PCI within integrated healthcare systems, such as the Veterans Affairs (VA) are unknown.

METHODS AND RESULTS

We evaluated all VA patients who underwent PCI from October 2007 through June 2010. To avoid the influence of Medicare eligibility on rates of stress testing use in the VA, we excluded Medicare eligible patients during the follow-up period. Hospital-level variation in risk-standardized rates of stress testing and the association with 1-year mortality and myocardial infarction was determined from Markov chain Monte Carlo methods. Among 10 293 patients undergoing PCI at 55 VA hospitals, 2239 (21.8%) had a stress test performed within 1 year of PCI and 3902 (37.9%) within 2 years. Most stress tests after PCI were performed with nuclear imaging (79.8%). The hospital-level risk-standardized rate of stress testing differed significantly from the average at 14 hospitals, with 8 (14.5%) hospitals significantly below and 6 (10.9%) hospitals significantly above the average stress testing rate. Hospital-level risk-standardized stress testing rates were not significantly correlated with risk-standardized mortality (Spearman ρ=-0.24; P=0.08) or myocardial infarction rates (Spearman ρ=0.20; P=0.14).

CONCLUSIONS

In the VA, nearly 40% of patients underwent stress testing in the 2 years after PCI, which is a third less than published studies from other healthcare systems. However, stress testing rates varied across VA hospitals, suggesting opportunities to optimize the use of stress testing are still present in integrated healthcare systems.

Impact of choice of imaging modality accompanying outpatient exercise stress testing on outcomes and resource use after revascularization for acute coronary syndromes

BACKGROUND

Exercise stress testing is commonly obtained after percutaneous coronary intervention (PCI) performed for acute coronary syndromes (ACS). We compared the relationships between exercise echocardiography and nuclear testing after ACS-related PCI on outcomes and resource use.

METHODS

Longitudinal observational study using fee-for-service Medicare claims to identify patients undergoing outpatient exercise stress testing with imaging within 15 months after PCI performed for ACS between 2003 and 2004.

RESULTS

Of 63,100 patients undergoing stress testing 3 to 15 months post-PCI, 31,731 (50.3%) underwent an exercise stress test with imaging. Among 29,279 patients undergoing exercise stress testing with imaging, 15.5% received echocardiography. Echocardiography recipients had higher rates of repeat stress testing (adjusted hazard ratio [HR] 2.60, CI 2.19-3.10) compared with those undergoing nuclear imaging in the 90 days after testing, but lower rates of revascularization (adjusted HR 0.87, CI 0.76-0.98) and coronary angiography (adjusted HR 0.88, CI 0.80-0.97). None of these differences persisted subsequent to 90 days after stress testing. Rates of death and readmission for myocardial infarction rates were similar. Total Medicare payments were lower initially after echocardiography (incremental difference $498, CI 488-507), an effect attributed primarily to lower reimbursement for the stress test itself, but not significantly different after 14 months after testing.

CONCLUSIONS

In this study using administrative data, echocardiography recipients initially had fewer invasive procedures but higher rates of repeat testing than nuclear testing recipients. However, these differences between echo and nuclear testing did not persist over longer time frames.

Medical specialty society-sponsored data registries: opportunities in plastic surgery

SUMMARY

Clinical data registries are commonly used worldwide and are implemented for a variety of purposes ranging from physician or facility clinic logs for tracking patients, to collecting outcomes data, to measuring quality improvement or safety of medical devices. In the United States, the U.S. Food and Drug Administration has used data collected through registries to facilitate the drug and device regulatory process, for ongoing surveillance during the product life cycle, and for disease appraisals. Furthermore, the Centers for Medicare and Medicaid Services, in certain instances, bases registry participation and submitting data to registries as factors for reimbursement decisions. The purpose of this article is to discuss the use of clinical data registries; the role that medical specialty societies, in particular, the American Society of Plastic Surgeons and The Plastic Surgery Foundation, can have in the development and management of registries; and the opportunities for registry use in plastic surgery. As outcomes data are becoming essential measures of quality health care delivery, participation in registry development and centralized data collection has become a critical task for plastic surgery to engage in to proactively participate in the national quality and performance measurement agenda.

Myocardial perfusion imaging after coronary revascularization: a clinical appraisal

Revascularization procedures, including percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG), are performed in many patients with coronary artery disease. Despite the effectiveness of these procedures, different follow-up strategies need to be considered for the management of patients after revascularization. Stress myocardial perfusion single-photon emission computed tomography (MPS) is a suitable imaging method for the evaluation of patients who have undergone PCI or CABG, and it has been used in the follow-up of such patients. Radionuclide imaging is included in the follow-up strategies after PCI and CABG in patients with symptoms, but guidelines warn against routine testing of all asymptomatic patients after revascularization. After PCI, in the absence of symptoms, radionuclide imaging is recommended and indicated as appropriate after incomplete or suboptimal revascularization and in specific asymptomatic patient subsets. On the other hand, the value of MPS late after CABG in risk stratification has been demonstrated even in the absence of symptoms. Thus, given the adverse outcome associated with silent ischaemia, it can be speculated that all patients regardless of clinical status should undergo stress testing late after revascularization. Larger prospective studies are needed to assess whether stress MPS will have an impact on the outcome in asymptomatic patients after revascularization.