Nick West, chief medical officer and divisional vice president of Global Medical Affairs, Abbott Vascular, discusses when intravascular imaging can be a useful tool to avoid “stent regret”.
When a patient finally arrives on the cath lab table for investigation of chest discomfort—often after suffering chronic anginal symptoms for years—the chances are that their cardiologist would not be surprised to find evidence of coronary artery calcification. Calcification might even have been picked up earlier in the patient’s workup—often on a screening coronary computed tomography (CT) scan—although its full extent may not be evident until an angiogram is performed.
That said, there is little doubt among cardiologists that conventional angiography underestimates the degree, extent and severity of calcification: the fact is that we have known this since early studies using intravascular ultrasound, and consequently, there is also a reasonably robust consensus that intravascular imaging improves the detection and quantification of calcification. However, every cardiologist will exercise their own judgment when deciding whether or not to undertake adjunctive imaging in order to determine the best treatment pathway. The potential danger at this point is “stent regret”—underestimating calcification and the need for enhanced plaque modification prior to stent deployment, leading to a suboptimal result that is often only salvageable with considerable effort.
Every interventional cardiologist that I have known has a story about stent regret, and if they do not, they are either incredibly skilled, have not done enough cases or have a particularly selective memory. I vividly remember one particular case perhaps eight or nine years ago: I was looking at a patient’s angiogram—an older gentleman with a relatively discrete lesion in a vein graft – thinking, “this will be straightforward.”
Following the philosophy often applied to such lesions that “less is more” in terms of vessel instrumentation, and without imaging the vessel, I directly stented. Even as I inflated the stent balloon, I knew that I had misjudged the lesion, and specifically the extent of calcification. Instead of seeing a perfect (angiographic) pipe-like result, I was confronted with what appeared to be an hourglass in the vessel. Cue repeated ballooning, balloon ruptures, ultra-high-pressure ballooning and a considerably longer case than the patient or I had bargained for, along with considerable expense incurred for the NHS, and a final result that was acceptable rather than optimal. As is often-quoted regarding working in a teaching hospital: “we are all here to learn,” and as such, I kept the angiogram as a salutary reminder of how one’s own abilities were not above reproach even after thousands of successful cases.
Hindsight makes it easy to say, “I wish I had imaged before…” or “I should have debulked/modified the calcification…” and it might have been easier to achieve the results that you—and obviously the patient—would want. In an era when both interventions themselves and the patients they are performed on are becoming ever more complex, especially when comorbidities that increase vascular calcification such as renal failure, diabetes mellitus and advanced age are rising in the percutaneous coronary intervention (PCI) population, this kind of problem is only going to become more frequent. The question is, how many cardiologists opt to use intravascular imaging because they have doubts about what they see on the angiogram and are then able to confirm or dismiss their hunch, thereby avoiding “stent regret?” Likely, very few in the past, but with accruing evidence that physicians change their PCI strategy when the presence and extent of calcification are identified with intravascular imaging[i], this may start to change. Today, intravascular imaging platforms with artificial intelligence-enabled software can automatically detect, quantify and display depth and arc of calcification within the vessel, reducing the variability of user identification and interpretation to streamline workflow and facilitate accurate and faster decision-making. This type of innovative technology simplifies recognition of calcification for cardiologists, allows better-informed treatments with the aim of ultimately reducing the burden of cardiovascular disease: improving quality of life and patient outcomes.
I know from experience that not every case requires intravascular imaging, and not every calcified lesion necessarily requires complex modification, but I also know that an angiographic image that suggests calcification leaves me wanting more information. When it comes to vessel preparation, physicians will have their own opinions on how to address calcification using the extent (arc, depth), their own experience, the tools they have available to them and evolving treatment algorithms. Having the certainty of imaging takes the guesswork on calcification out of the equation, leaving more time for the physician to spend on the treatment plan, and perhaps less time on “stent regret.”
[i] Bezerra, H. et al. Analysis of changes in decision-making process during OCT-guided PCI—Insights from the LightLab Initiative. EuroPCR 2020.