A real-world analysis reveals that women are consistently less likely to undergo intracoronary imaging as part of percutaneous coronary intervention (PCI), even though it benefits both sexes equally.
Results from nearly all PCIs performed in England and Wales between 2006 and 2019 showed the absolute rate of intracoronary imaging with either intravascular ultrasound (IVUS) or optical coherence tomography (OCT) was 5% lower in the later study years among women at 14.5% compared with 19.6% in men (P < .001).
After adjustment, female sex was an independent predictor of lower intracoronary imaging use (odds ratio [OR], 0.93; 95% CI, 0.91-0.96), according to the study, published today in JACC: Cardiovascular Interventions.
“One of the thoughts I had when we were running this analysis was, well, maybe the indications for that imaging, as recommended by guidelines, are less common in women,” Mamas Mamas, MD, told theheart.org | Medscape Cardiology. “So what we did was to look at just cases where imaging is recommended by the EAPCI [European Association of Percutaneous Coronary Intervention].”
Again, the use of intracoronary imaging was consistently lower among women than among men for all of the following EAPCI recommended indications:
Acute coronary syndrome: 11.6% vs 12.3% (P < .01)
Stent thrombosis: 30.9% vs 34.9% (P < .01)
Long lesions: 13.1% vs 16.3% (P < .01)
Chronic total occlusions: 16.2% vs 18.3% (P < .01)
Left main stem PCI: 55.1% vs 57.5% (P < .01)
In-stent restenosis: 28.0% vs 30.7%
Calcified lesions: 36.6% vs 40.1% (P < .01)
Renal disease: 17.4% vs 19.5% (P < .01)
As to what might be driving the lower use, Mamas dismissed the argument that women undergo much simpler PCI, which wouldn’t benefit from imaging. Women do have smaller coronary arteries, however, and there is a belief that it’s easier to eyeball the size of vessels that are smaller rather than larger.
“I’m not convinced that’s entirely true,” he said. “I don’t have a good answer for you, I’m afraid. I don’t really know why we’re seeing it. I just think it’s one of those disparities that is important to highlight.”
Central to this belief is that the benefits of intracoronary imaging were found to be similar in men and women. Intracoronary imaging was associated with lower adjusted odds of in-hospital mortality (OR, 0.56; 95% CI, 0.48-0.64) and major adverse cardiac and cerebrovascular events (OR, 0.83; 95% CI, 0.76-0.91) in women and men (OR, 0.48; 95% CI, 0.44-0.53 and OR, 0.75; 95% CI, 0.71-0.80, respectively), compared with nonimaging groups.
“This really should be a call to arms, particularly given that we show this disparity persists, even in guideline-recommended cases where we should be using it,” said Mamas, from the Keele Cardiovascular Research Group, Keele University, and Royal Stoke University Hospital, England.
“Actually, I would argue that we should be using more imaging in women than men anyway because many of the presentations for acute coronary syndromes in women, like spontaneous coronary artery dissection or MINOCA [MI with nonobstructive coronary arteries], you often need intracoronary imaging to make that kind of diagnosis,” he observed.
Getting Worse, Not Better
Previous studies have shown that women are less likely than men in acute coronary syndromes to receive the transradial approach and P2Y12 inhibitors, but none have specifically looked at intracoronary imaging, Mamas said.
To fill the gap, the researchers drew on data from 994,478 patients in the British Cardiovascular Intervention Society registry, of whom, 8.4% of 738,616 men and 7.9% of 255,862 women received intracoronary imaging.
Women in the imaging group were older, more likely to be an ethnic minority, and more likely to undergo PCI for non–ST-segment elevation MI than their male counterparts.
One of the more surprising findings was that rates of IVUS and OCT were superimposable between the sexes at the start of the study but quickly diverged starting in around 2012, when the technology took off, Mamas said. In the most recent data, use was about 3% lower in women overall and rising to 6% in those with stable angina.
“Whilst the disparities between men and women are significant, the bigger question is why are we using so little imaging in guideline-recommended cases where there is a benefit?” he said.
Possible actionable items, he suggested, include providing older physicians who didn’t have access to intracoronary imaging during their training with opportunities in their cath lab or with industry sponsors to increase their skills and confidence. Intracoronary imaging use could also be routinely captured in US and European PCI registries and used as a quality metric.
“In left main, you see a massive difference between centers, and that’s the kind of data that drives discussion,” Mamas said. “If we start reporting quality metrics, such as radial use, intracoronary imaging, P2Y12 inhibitors by center, then you’ve got something to benchmark centers against.”
Nathaniel Smilowitz, MD, an interventional cardiologist at New York Langone Health in New York City, who was not associated with the study, said that it’s troubling to see that the utilization intravascular imaging is so low, despite randomized trials and large meta-analyses showing a mortality benefit associated with its use in PCI.
“Even among men, only 19.6% in the later years were getting intravascular imaging performed to guide their coronary intervention, so one out of five,” he said. “There are opportunities to improve.”
Smilowitz said he’s also perplexed as to why adoption would be lower in women but that the findings echo those in other domains where women receive less intensive cardiovascular therapy.
“There’s no biological, really plausible, mechanism as to why the need for intravascular imaging would be lower and, particularly, because they showed in stent thrombosis, for example, where intravascular imaging is tremendously important, there were still sex differences,” he said. “So even with clear indications for imaging, women just received the optimal therapy less often than men. It’s disappointing.”
Smilowitz agreed that there may be a need to incorporate intravascular imaging into metrics, which are reported back to physicians, potentially even for comparisons with peers or regional rates to incentivize physicians to improve uptake.
“As a society, we’ve been quite slow to integrate intravascular imaging to guide PCI and we can do better,” he said.
Co-author Nicholas L. Mills, MD, is supported by a Chair Award, Programme Grant, and Research Excellence Award from the British Heart Foundation. All other authors report having no relevant financial relationships. Smilowitz is on an advisory board for Abbott.
JACC: Cardio Interv. Published online June 20, 2022. Full text
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