Two types of patients with coronary stenosis remain eligible for revascularization by angioplasty from the outset. Starting with individuals suffering from acute coronary syndrome. In this population, urgent treatment consists of offering rapid coronary angiography, then, most often, treatment by angioplasty or bypass surgery. And this sequence does not seem likely to evolve for this population for the moment.
On the other hand, in patients with stable, chronic, symptomatic coronary stenosis (angina pectoris, shortness of breath, etc.), also eligible for revascularization, “coronary CT, which already occupies an increasingly important place in the diagnosis of coronary artery disease, could contribute to thinking about the best revascularization strategy”predicts Dr. Frédéric Bouisset. This perspective at least seems to be gaining more and more attention.
At the forefront of recommendations
In fact, in cases of symptomatic chronic coronary stenosis, a CT scan is already recommended. “Historically, this tool was considered suitable only to rule out any possible coronary disease, so it was used rather in low-risk populations, based on its good negative predictive value and thus, in the absence of coronary narrowing on the scanner, we could be reassured”recalls Dr. Bouisset.
However, the situation could change, linked to significant technological developments. “The resolution of the coronary scanner has progressed greatly”says Dr. Bouisset. Also, viewing the coronary arteries in more detail is now possible.
“We are now able to observe the coronary arteries in more detail on a CT scan, and thus characterize not only the severity of the lesions, but also the composition and distribution of atherosclerotic plaques in the coronary tree in a more precise manner. reliable. »
Thus, before moving on to coronary angiography, in the event of coronary narrowing, more information provided by the scanner could already be used in order to best prepare for the placement of a stent. “We can, using the scanner, consider which catheter will be most suitable for visualizing the coronary artery, then estimate the length of the lesion, assess the presence of calcium, which is of great importance in the preparation strategy before angioplasty, and, if necessary, understand its distribution, etc., already directing treatment towards the placement of stents or bypasses, before coronary angiography which will definitively confirm the lesions, in an invasive manner”explains Dr Bouisset.
In addition, the scanner makes it possible to better assess the functional impact of possible stenoses. “Mathematical models, some of which are already used clinically, make it possible to measure the impact on the coronary flow caused by a stenosis, and thus to select the truly problematic strictures, to be targeted for treatment”explains Dr. Bouisset. And certain software would also make it possible to model the response to the treatments considered – whether it is a stent or a bypass. So in the long term, coronary angiography could be used less and less for its diagnostic value.
“The precision of the coronary lesion assessment by CT scan will make it possible to decide on the revascularization strategy to be implemented”predicts Dr. Bouisset. At least that’s what a certain number of researchers imagine on this subject.
-A study of practices
And new data could soon confirm this hypothesis. The cardiologist mentions in particular an international randomized trial, in progress, in which a thousand patients should receive either an angioplasty planned on the data of the scanner, or an angioplasty according to the usual procedure, that is to say guided by the angiography and in this case, also by endocoronary ultrasound (IVUS). « This is a non-inferiority study (between the two practices). »
In addition, the cardiologist mentions work concluding that certain decisions, even major interventions such as bypass surgery, can indeed be taken solely on the basis of a CT scan, without recourse to coronary angiography. “ Overall, this will make it possible to optimize our decisions by better using patient data that already exists, since these scanner examinations are already carried out in the patient pathway, to make the initial diagnosis of coronary artery disease, and to take them upstream of the room of catheterization, in a peaceful context »summarizes Dr Bouisset, who compares this evolution to the Tavi pose.
“First of all, Tavi, we do a CT scan, which we analyze to choose the valve and vascular access that seem most suitable for the patient we are treating. Interventional cardiologists and cardiac surgeons are therefore already using scanner data to plan their procedures, particularly valvular ones. Tomorrow, they will also use the scanner when it comes to planning myocardial revascularization procedures,” predicts the cardiologist.
And this, without additional cost, at least theoretically: if the scanner is already used for anatomical diagnosis, the analysis of this information to derive functional data, that is to say the impact of stenoses on the flow, it , can be costly. “American society HeartFlow proposes to assess the functional impact of coronary stenosis on CT scan, but for a price that is still not negligible and to date not reimbursed in France”regrets Dr. Bouisset. Less expensive alternatives are being developed to meet this need.
And other obstacles could prevent the coroscanner from taking a greater place in the care pathway. Starting with accessibility to scanners of sufficient quality — distributed unevenly across the territory.
In addition, training for cardiologists appears necessary. “Extracting information to plan an angioplasty is a learned process, and we will learn it, as we did for planning structural procedures”predicts Dr. Bouisset.
