Uptake of Intracoronary Imaging-Guided Percutaneous Coronary Intervention Among Female Patients in the State of Michigan: An Analysis of a BMC2 Initiative

Introduction

Women experience worse outcomes across many cardiovascular disease states in comparison to men, including worse health status and clinical outcomes after percutaneous coronary intervention (PCI).¹ These differences are likely due to multiple factors, including differences in the application of guideline- and evidence-based therapies. For instance, despite a higher risk of bleeding compared with men, women are less likely to undergo PCI via radial artery access.² Another potential mediator of differences in outcomes by sex may be related to the use of intracoronary imaging (ICI) to guide and optimize PCI.

Multiple randomized controlled trials have demonstrated that using ICI to guide and optimize PCI is associated with improved clinical outcomes compared with PCI guided solely by angiography.³ Despite robust data and recent guideline recommendations, the uptake of ICI-guided PCI has remained low. In 2020, the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2), a statewide collaborative focused on improving PCI care quality in Michigan, launched a multifaceted quality improvement initiative focused on increasing rates of ICI-guided PCI.⁴ Recently, Madder et al reported a significant and progressive increase in rates of ICI-guided PCI in Michigan from 7.3% in 2019 to 44% in 2023.⁴

With this dramatic increase in ICI-guided PCI over time, we sought to evaluate the temporal association of the BMC2 quality improvement initiative with rates of ICI-guided PCI in female and male patients between 2019 and 2024.

Materials and methods

The study population consisted of all patients discharged after PCI between January 1, 2019, and December 31, 2024, at all 51 nonfederal hospitals in the State of Michigan, and enrolled in BMC2. Details of the BMC2 quality collaborative have been previously described.⁴ Briefly, BMC2 collects data on all PCIs performed at nonfederal hospitals in the state of Michigan using the National Cardiovascular Data Registry CathPCI data collection framework, along with novel additional data elements prospectively defined and collected through the BMC2 registry. In 2019, BMC2 began collecting data on the use of ICI to optimize PCI, defined as the use of either intravascular ultrasound or optical coherence tomography after the decision was made to proceed with PCI. The use of ICI to solely assess lesion severity or inform the need to perform revascularization was excluded from this definition. Due to the overall low rate of ICI use in Michigan, BMC2 launched a quality improvement initiative in 2020 intended to increase the use of ICI. This multifaceted initiative included regular site and physician feedback on their use of ICI to optimize PCI, physician-led educational sessions on ICI use, creation of a best practice protocol document describing the use of ICI to optimize PCI, and an ICI algorithm poster that was made freely available to be posted in catheterization laboratories. Further details of this quality improvement initiative have been previously described.⁴

The primary analysis focused on evaluating the trend in ICI-guided PCI by patient sex. ICI-guided PCI was defined as the use of intravascular ultrasound or optical coherence tomography after the decision was made to proceed with PCI. Secondary analyses consisted of evaluating trends in ICI-guided PCI by sex in the subgroup of patients undergoing PCI for left main disease, in-stent restenosis, or in-stent thrombosis.

Temporal trends in ICI-guided PCI were evaluated using the Cochran-Armitage trend test. To assess the extent to which the adoption of ICI over time varied by sex after accounting for selected patient clinical and procedural characteristics (Supplemental Table S1), a logistic regression model was used, including a year of procedure by patient sex interaction term.⁴ Missing covariate data were imputed using the classification and regression tree method within the R package “mice”. All analyses were performed using R version 3.4.1 (R Foundation for Statistical Computing).

Results

Between January 1, 2019, and December 31, 2024, a total of 175,918 PCIs were performed at 51 nonfederal hospitals in Michigan. ICI information was unavailable for 3942 cases (2.2%), which were excluded from this analysis. Of the remaining 171,976 procedures, 54,683 (31.8%) were performed in female patients. Over the study period, there was a significant and progressive increase in the rate of ICI-guided PCI in female and male patients (Figure 1A). Among female patients, the rate of ICI-guided PCI was 7.0% in 2019 and increased to 54.2% in 2024 (P for trend <.001), whereas among male patients, the rate of ICI-guided PCI increased from 7.3% to 56.0% over the same time period. There was no significant difference in ICI-guided PCI trends by sex (P = .21) after adjusting for clinical covariates.

Figure 1.

Rates of intracoronary imaging-guided percutaneous coronary interventions. All cases (A) and (B) among those receiving PCI for the treatment of left main disease, in-stent restenosis, or in-stent thrombosis from January 1, 2019, through December 31, 2024, stratified by patient sex. ICI, intracoronary imaging; ISR, in-stent restenosis; IST, in-stent thrombosis; PCI, percutaneous coronary intervention.

For key subgroups, including PCIs performed for the treatment of left main disease, in-stent restenosis, or in-stent thrombosis, ICI-guided PCI among females increased from 10.4% in 2019 to 65.3% in 2024 (P for trend <0.001) (Figure 1B). There was no significant difference in trends by sex (P = .61) in this subgroup after adjusting for clinical covariates. Each calendar year increase in time was associated with a 69% increase in the odds of ICI-guided PCI among females who underwent PCI for left main disease, in-stent restenosis, or in-stent thrombosis (adjusted odds ratio, 1.69; 95% CI, 1.63-1.74; P < .001).

Discussion

In this analysis of over 170,000 PCIs, including more than 50,000 procedures performed in female patients across 51 centers between 2019 and 2024, we observed a significant increase in the rate of ICI-guided PCI in both female and male patients with no significant difference in annual trends by sex among all PCIs and among those undergoing PCI for the treatment of left main disease, in-stent restenosis, and in-stent thrombosis.

In a study evaluating ICI use by sex among nearly all PCIs performed in England and Wales between 2006 and 2019, Rashid and colleagues noted the rates of ICI use were 8.4% in men and 7.9% in women during the study period. However, they noted that by the end of the study period, absolute rates of ICI use were 5% lower in women than men (women 14.5% vs men 19.6%; P < .001).⁵ Notably, the authors found female sex to be an independent negative predictor of ICI use with an odds ratio of 0.93 (95% CI, 0.91-0.96).⁵ A meta-analysis of ICI-guided PCI studies by Ezenna and colleagues reported that women comprised only 23.9% of the study population.⁶ This underrepresentation underscores a critical gap in equitable care delivery and highlights the need for broader, system-level initiatives across sites to increase the adoption of intravascular imaging (ICI) in a more equitable manner. Our work adds to this body of literature, demonstrating that a novel, robust, multifaceted quality improvement initiative was associated with significant increases in ICI use overall without significant differences in the rate of uptake by sex.

The widespread adoption of ICI in Michigan may not solely be attributed to the statewide quality improvement initiatives and strong support from the interventional community. The authors acknowledge that the observed results may be influenced by the robust and expanding body of literature highlighting the importance of ICI-guided PCI, which have led to changes in societal guidelines.⁷ Additionally, factors such as enhanced education during interventional cardiology fellowships and the advancements in cardiac catheterization labs across Michigan, which have integrated ICI technology, may have also contributed to the increased utilization of ICI. However, overall, the favorable trends observed reinforce the value of such coordinated efforts and highlight the need for future initiatives to address remaining gaps in PCI practice and to assess their impact on clinical outcomes.

In conclusion, the implementation of a statewide quality improvement initiative was associated with dramatic increases in the rates of ICI-guided PCI among both female and male patients, and the pace of uptake did not differ significantly by sex. We encourage other states to implement similar quality improvement initiatives to facilitate equitable increases in ICI-guided PCI.

Declaration of competing interest

Ryan D. Madder reports speaker honoraria from Abbott Vascular, Boston Scientific, and Corindus; has served as a consultant to Abbott Vascular, AngioWave Imaging, Boston Scientific, MiRus, Nanoflex Robotics, Orchestra Biomed, RapidAI, and SpectraWAVE; has received research support from AngioWave Imaging, Corindus, Microbot Medical, and Nanoflex Robotics; and serves on the advisory boards of Boston Scientific, Gentuity, Medtronic, and SpectraWAVE. Eric Cantey owns equity in Xtasis, Inc; is a consultant for Philips, Boston Scientific, J&J-Shockwave, and Heartflow; and serves on the advisory board of J&J-Abiomed. Devraj Sukul owns equity in Stallion RPG and is a consultant for AngioWave Imaging and RapidAI. Sabina Kumar, Milan Seth, Mark A. Zainea, Brittany Fuller, Prasanthi Yelavarthy, and Elizabeth Pielsticker reported no financial interests.