Author + information
- Timothy A. Joseph, MD,
- Jessica Lehrich, MS,
- Paul S. Chan, MD, MSc,
- Jeptha P. Curtis, MD,
- Nihar R. Desai, MD, MPH,
- Venkatesh L. Murthy, MD, PhD,
- Nick Curzen, BM, PhD and
- Brahmajee K. Nallamothu, MD, MPH∗ ()
- ↵∗University of Michigan Cardiovascular Center, 1500 East Medical Drive, SPC 5869, Ann Arbor, Michigan 48109-5869
The appropriate use criteria for coronary revascularization emphasize the value of noninvasive stress testing and/or fractional flow reserve (FFR) to guide the performance of elective percutaneous coronary intervention (PCI) (1). Lin et al. (1) previously reported that fewer than one-half of Medicare beneficiaries treated with elective PCI in 2004 underwent prior stress testing. Since this publication, there has been growing emphasis on the value of FFR-guided revascularization as an adjunctive tool in the catheterization laboratory to help with documenting ischemia before PCI in patients who do not undergo stress testing (2). However, national estimates from 2009 and 2010 have shown low use of FFR in an unselected cohort of patients undergoing both elective PCI and PCI for acute coronary syndromes with no clear understanding of the influence of stress testing on this decision (3). More contemporary estimates of the use of FFR before elective PCI, in particular, are unknown, as is its relationship with stress testing.
To understand these questions, we used 2012 and 2013 data for a 20% sample from the Medicare Carrier, Medicare provider and analysis, Outpatient and Denominator files using Healthcare Common Procedure Coding System, and International Classification of Diseases-9th Revision codes for the following diagnoses and procedures: PCI, FFR, acute myocardial infarction, stress testing, coronary artery bypass grafting, and valve surgeries (codes available from authors on request). Our cohort was restricted to the index (i.e., first) PCI in Medicare beneficiaries aged 65 to 99 years old who were fee-for-service eligible a year before and a month after their procedure. To create a cohort of elective PCI, we excluded beneficiaries with recent acute myocardial infarction (within 30 days of PCI); those who transferred from another hospital or were evaluated in the emergency department at the time of their index PCI; and those who had a prior PCI, coronary artery bypass grafting, or valve procedure within a year of the index PCI. We report the proportion of patients with FFR performed at the time of PCI and the proportion of patients with prior stress testing within 90 days of PCI. To examine if the decision to use FFR was influenced by the presence of prior stress testing, we constructed multivariable logistic regression models that controlled for age, sex, race, and geographic region. All data were analyzed using SAS version 9.3 (SAS Institute Inc., Cary, North Carolina).
Our study cohort included a total of 39,946 elective PCIs between 2012 and 2013. Mean age was 76.5 with 36.5% women and 5.3% black persons. Overall, 2,856 (7.1%) underwent FFR and 20,415 (51.1%) underwent stress testing within 90 days of their elective PCI. In contrast, a total of 18,073 (45.2%) underwent neither stress testing nor FFR (Figure 1). After multivariable adjustment, patients were more likely to undergo FFR without prior stress testing (odds ratio: 1.10; 95% confidence interval: 1.02 to 1.18; p < 0.001), but FFR use was low in both groups (6.8% vs. 7.5% in those with and without prior stress testing, respectively).
This nationwide study of the frequency of FFR use before elective PCI demonstrates its overall low use of well under 10%. Furthermore, we found persistent underuse of overall physiological assessment with either FFR or prior stress testing at approximately 45%, and a modest but significant relationship between these 2 tests with lower FFR use associated with prior stress testing. These findings extend prior work by examining use of FFR following the publication of landmark clinical trials that increasingly support its role in decision-making before elective PCI.
Our study has several limitations to consider. First, we only examined elective PCI and did not include those who underwent FFR during diagnostic catheterization without PCI. FFR use in this case may have prevented PCI, and this possibility should be examined in future work. In addition, we are unable to account for all factors driving use of PCI, such as clinical symptom severity, medical therapy failure, or lesion characteristics (e.g., percent stenosis). However, the assessment of factors, such as angina and stenosis severity, is prone to variability in interpretation and potentially subjective (4,5). Finally, many patients in our cohort may have had equivocal stress testing results prompting diagnostic catheterization. In this case, FFR would be appropriate despite the prior stress testing, and this may have led to the clinically insignificant differences of FFR between those with and without prior stress testing.
Our findings suggest that better strategies to improve decision-making in patients undergoing elective PCI are urgently needed despite the availability of new tools, such as FFR. We suspect multiple and complex barriers to FFR use may exist that have limited its overall dissemination, including reimbursement, increased time and resource cost, and skill sets required for its clinical performance and interpretation. As with other cardiovascular tests and therapies, future implementation studies to examine these barriers and to understand facilitators of more appropriate FFR use are warranted.
Please note: Dr. Curtis has received salary support from the American College of Cardiology and the Centers for Medicare and Medicaid Services; and has equity holding in Medtronic. Dr. Desai has received research funding from Johnson & Johnson, through Yale University, to develop methods of clinical trial data sharing and from the Centers for Medicare & Medicaid Services to develop and maintain performance measures that are used for public reporting; and is supported by grant K12 HS023000-01 from the Agency for Healthcare Research and Quality. Dr. Murthy owns stock in General Electric, Mallinckrodt Pharmaceuticals, Cardinal Health, Abbvie, Baxter International, and Medtronic. Dr. Curzen has received unrestricted grants from Boston Scientific, Medtronic, HeartFlow, Haemonetics, St. Jude Medical, and Volcano; and has received speaker fees/consultancy from HeartFlow, Haemonetics, and St. Jude Medical. Dr. Nallamothu has received honorarium from the American College of Cardiology and American Heart Association for editorial work on their online websites and journals. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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