Editorial

Optimization of coronary IVUS-guided bifurcation PCI in Argentina: between the “ideal” and the “possible”

Daniel Mauro

MTFAC, MTSAC / Instituto del Corazón San Rafael, San Rafael – Mendoza – Argentina / Presidente del Comité de Cardiopatía Isquémica de FAC.

Corresponding author’s address
Dr. Daniel Mauro MTFAC, MTSAC
Instituto del Corazón San Rafael, San Rafael – Mendoza – Argentina
Postal address: Av. El Libertador 950 Piso 4, 5600 San Rafael, Mendoza
E-mail

INFORMATION  

Received on May 31, 2022 Accepted after review on June 2, 2022 www.revistafac.org.ar

There are no conflicts of interest to disclose.

Keywords:
Coronary bifurcation .
Angioplasty.
Intravascular ultrasound

The strategies for the treatment of coronary bifurcation lesions are as numerous as controversial, with an improved or infallible technique “suitable for all audiences” not existing to date. Thus, it seems that what is most adequate springs from planning a “customized” approach, made from a thorough assessment, not only angiographical, but also essentially by means of intravascular ultrasound (IVUS) or other techniques such as optical coherence tomography (OCT).

IVUS is thus an auxiliary tool for the angiographic assessment of complex lesions such as those in the left main coronary artery or in bifurcations, since it provides more information on the vessel wall, calcifications, ostial or eccentric lesions, lesion extension and positive remodeling (capacity to contain plaques without vessel lumen compromise).

Using IVUS to improve lesion dilatation and acute angiographic outcome goes back to the pre-stent era. Different studies show the efficacy of IVUS in balloon sizing and the estimation of positive remodeling extension[1]. During the 1990s, using conventional metallic stents (BARE metal stents), numerous observational studies explained that reaching a transversal section area with larger diameter and using higher insufflation pressures, guided by IVUS, achieved a better stent apposition and smaller restenosis rates[2,3,4].

Currently, there are no doubts that the populations that benefit the most from using IVUS are these undergoing left main coronary artery (LMCA) and coronary bifurcation angioplasties, with particular emphasis on those requiring stent placement[5].

In line with this, a systematic review and meta-analysis on IVUS-guided percutaneous coronary interventions (PCI) in bifurcation lesions proved that this strategy was associated to more clinical benefits in comparison to angiography-guided PCI[6]. This study, which included 7830 patients with bifurcation lesions involved in five selected studies, pointed out in early follow-up, a significant less incidence of major adverse cardiac events (MACE) rates and also lower rates of death by cardiac cause in distant follow-up.

Delving into more details about some technical aspects of PCI in complex bifurcation lesions, such as using the two-stent technique in a scenario of provisional stent placement, the DEFINITION II trial, a controlled and randomized trial which clearly established the “complex bifurcation lesion” criteria based on the lesion length in the side branch, percentage of stenosis, degree of calcification, bifurcation angle, and so on, proved that a two-stent technique is superior to a provisional approach in truly complex bifurcation lesions, in a 12-month follow-up. This trial also adds to the evidence that an initial 2-stent strategy could be more appropriate in truly complex bifurcation lesions[7].

An impeccable single-center study on optimization through IVUS of coronary bifurcation angioplasty performed in the Department of Interventionist Cardiology of the Cardiology Institute of the Sanatorio Británico de Rosario, presented in this issue, reaffirms what has been observed up to here, fully coinciding with international literature[8]. With excellent results in terms of mortality and requirement for new revascularization in early and distant follow-up, this registry displays a great technical capacity of the task group, and once again, it shows that the results reached by interventional cardiology in our country are completely comparable to those observed in any other center at international level and/or multicenter registries.

As the authors themselves acknowledge, the sample size may not allow to draw major conclusions about some safety aspects, but it also indicates the particular dedication by operators to optimize results in every case (an average of 2.3 patients/month), which is not a minor detail.

The publication of this study also shows the requirement to extend IVUS use to optimize results in complex TCA to the largest universe possible of interventional cardiology services in our country. This appears to be fundamentally limited, currently, due to medical insurance and expenses not considered by the health care system financiers; and not because of lack of interest or technical shortcomings by operators.

According to data presented by the Colegio Argentino de Cardioangiólogos Intervencionistas – CACI (Argentine College of Interventional Cardiovascular Angiography Specialists) during the first days of December 2021, there were 357 laboratories of hemodynamics throughout the country. On the other hand, an optimistic estimation from industry data indicates that approximately 60 IVUS devices are operational in our area. This means that a percentage below 20% of Interventional Cardiology Services registered in the CACI perform IVUS as a routine currently, or have the possibility of doing it.

This shows as well, that access to this technology by many services, and therefore by many patients, is limited. If consulted about the immediate and distant benefits of using IVUS in the therapeutic approach of complex lesions such as bifurcation or LMCA lesions, its indications and/or contraindications, I assume that a very large majority of interventional cardiologists in our country may enumerate them with complete accuracy, and that we would all agree on the virtues and the need to have this tool for treatment. Nevertheless, in daily practice this does not happen. Why?

The unequivocal response to this rhetorical question is undoubtedly, the impossibility of financing this practice, as the different health care system financiers (public, medical insurance or pre-paid medicine), with a few exceptions, are not willing to accept it and/or cover its costs, essentially because they fail to understand its cost-effectiveness. Thus, all financiers pay (after the procedure is done) the higher cost of losing chances, whether by reintervention requirement, or higher rate of MACE as pointed out previously. Likewise, the learning curves for IVUS techniques by operators are slowed down, and the costs of consoles and devices remain high, due to their scarce implementation.

Surely, it is here where a sound medical and scientific representation of interventional cardiology in Argentina should also reach and participate in the financial aspects of the specialty, together with the other actors of the health care system.

But while chasing this ideal, we should continue to optimize what is possible. Undoubtedly, part of this is implementing the lessons learned about IVUS for more than 2 decades.

We saw an example in the study by Dr. Daniel A. Zanuttini et al, where after IVUS assessment, 22.6% of cases presented immediate reintervention requirement due to stent hypoexpansion or lack of apposition by some struts. This is probably a direct consequence of the discrepancy observed in quantitative coronary analysis (QCA), which identifies an average reference diameter for the main axis of the branch smaller than the estimation by IVUS (2.9±0.6 mm vs 3.5±0.4 mm, respectively). Something similar happens for the extension of the lesion to treat, with greater extension of the plaque in IVUS assessment. Clearly, this shows that the “luminogram” represented by angiography, does not achieve to categorically identify plaque extension or volume.

Other examples of lessons to apply are pre-dilatation of the side branch, the performance of the POT (proximal optimization technique) technique before attempting to cross a guidewire to the side branch, the final kissing balloon technique when two stents are implanted, among several other techniques that are obviously to be managed exclusively by interventional cardiologists, whose description exceeds the aim of this editorial.

Finally, we should emphasize the importance of extending this type of registries, being inspired by global experience, but learning from local experience, and most of all, working jointly with the different scientific societies, medical colleges and professional associations as active and relevant members of the health care system, to realize the “ideal”.

BIBLIOGRAPHY

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