Tabla 1. Angiographic and Clinical Basal Characteristics (n=62)

Tabla 2. Events (n=45).

Figura 1. Diagram of patient inclusion flow.

INTRODUCTION

Since the publication in 2016 of studies such as the SMART-STRATEGY1 or the EBC-TWO2 which support the use of a single stent (provisional stenting) like an initial strategy in angioplasties on bifurcations, the technique of two stents like culotte or double-kissing-crush only were reserved for less than 10% of these procedures, in which the secondary vessel was of great caliber, with complex anatomy or angulation, and with an extension of ostial plaque higher than 5 mm. In 90% of the remaining cases, the initial strategy of provisional-stenting was the recommended one1-4, and switch to two stents was only suggested when, after implanting the stent of the main vessel, the result on the secondaryvessel was suboptimal or showed flow commitment. The recommended techniques for this switch were the T-stent, T-and-protrusion (TAP) and, hardly ever, culotte.

More current studies such as DEFINITION5,6support the initial strategy with two stents, and techniques like DK-crush and TAP are showing better results than provisional-stenting regarding death, thrombosis/infarct and restenosis.

The objective of this study is to analyze the clinical and angiographic results of the systematic use of TAP technique in our unit, in terms of death, infarct (TVM1: target vessel myocardial infarction) and necessity of reintervention due to restenosis (TLR: target lesion revascularization), and compare these results with the ones shown in international registries.

MATERIALS AND METHODS

Itisaboutareportofobservationalandprospectivecases.

Patients with severe coronary injuries in bifurcation zones were included. They required technique of two stents (Figure 1). Those patients who had injuries in bifurcation of the trunk of the left coronary were excluded.

The technique used in all of them was TAP8.9, either by initial intention, or as a switch from an initial strategy of provisional stent where there was commitment of secondary branch. We will describe some technical aspects adapted to our experience as follows:

- Catheters: With a 7 Fr diameter in all the cases, the catheters guide used were EBU/XB or JL for the left coronary, and JR, EBU or AL 0.75 for the right coronary; in our experience we use EBU catheter (of left coronary) for some complex right coronary angioplasties obtaining more support than the one offered by a Judkins JR and with less risk of traumatism/dissection ostial/proximal than a Amplatz AL catheter.

- Basal angiographies and projections. We always make multiple basal angioplasties that afterwards will serve for the decision making. We consider it important to extreme the cranial angulations (40o or more) and to always make left axial projections (for average DA) and spider (for DA or proximal Cx). We suggest always working with the image of reference in parallel.

- Guides. We do not prefer any guide especially, although we recommend hydrophilic guides for critical or angulated ostial injuries of the secondary branch. We always advance two guides 0.014” workhorse (Choice, PT2 or BMW) to main vessel and secondary branch.

- Pre-dilatation. The injury of the main vessel was pre-dilated at high pressure in all the patients, and the ostium of the secondary branch only in those where we had the initial intention of using two stents (secondary vase of great caliber, with marked angulation or complex anatomy and with significant ostial injury); we try not to be aggressive in the initial pre-dilatation of the secondary branch in order to avoid dissections that later make the guide re-crossing difficult.

- Stent. During the stent implantation of the main vessel, we always leave the guide of the secondary vessel “caged”. We try to leave at least 6 mm of stent proximal to the bifurcation in order to have space in case of requiring kissing-balloon; this is important in 0-1-1 or 0-1-0 type bifurcations.

- Post dilatation. After implanting the stent of the main vase, we post dilate el segment proximal to itself, with a one diameter balloon of at least 0.25 mm higher to the stent (POT: proximal optimization technique). We ideally always look for postdilating all the stent segment from the proximal edge up to the birth of the secondary vessel in such a way that the cells facing to the ostium of this lateral branch are enough expanded; besides, the systematic POT use gives us other advantages: to ensure apposition of the stent and to enable the pass of balloons or stents (if it is necessary) without deforming the proximal edge of the stent implanted in the main vessel.

- Angiographies of control. It is very important to make at least 3 orthogonal angiographies to confirm or discard ostial affectation of the secondary branch. We advise to make the same projections that we made basally. Do not forget projections as the left axial to evaluate diagonal branches (in cranial or right axial AP there is often superposition of the diagonal ostium) and flow projections to evaluate marginal branches (spider, AP flow).

- Guide crossover. We only cross over guides if we want to bifurcate and treat the secondary branch. We ideally cross the guide of the main vessel towards the secondary vessel and once the position is ensured, we take out the “caged” guide from the secondary vessel which will be advanced to the main vessel. We must be very careful during the taking out of the trapped guide, controlling the excessive “intubation” of the guide catheter; we recommend to maintain a sustained moderate strength and avoid intermittent pushes with risk of breaking it. In the case that the intubation of the guide catheter is unavoidable, we recommend you to pass a deflated balloon through the guide of the main vessel for this intubation to be the most controlled and coaxial possible, avoiding dissections of segments proximal to the vessel. During crossovers and passes of guides, we must look for controlled movements of coming and going, avoiding exaggerated torques and turns which could lead to guide intercrossing, making the next steps more difficult.

- Pre-dilatation of the secondary branch ostium. In case we decide to treat the secondary branch, the next step will be to dilate the stent cells of the main vessel facing the ostium; in order to do so, we suggest that the balloon must pass from 1.5 mm to 2.0 mm for isolated insufflation over the ostium of the secondary vessel and following the pre-dilatation with kissing-balloon; we suggest making this kissing-balloon positioning in main vessel the same balloonthat will be later used for the stent implantation.

- Stent implantation in secondary vessel. After pre-dilating with kissing-balloon, we will take out the balloon of the secondary branch, and we can advance the balloon that we have just used in the main branch towards the distal segment of the vessel temporarily; this will give us better support to advance the stent towards the ostium of the secondary branch. After passing this stent, we take back the balloon of the main vessel up again to the kissing position and then we start looking for the accurate position for the ostial stent. We always suggest making multiple projections in order to ensure a correct coverage of the secondary branch ostium. At this point the image improvement techniques such as StentBoost (Philips) or ClearStent (Siemens) are very useful. At the moment of implanting we must initially insufflate the stent in an isolated way (in order to avoid to be moved by accident) and then we can carry out the kissing. In our experience we do not suggest making POT due to the risk of deforming the neocarina that we have just made. If it is necessary, we use the POT (by deformation or excessive traumatism of the proximal edge of the stent during the passing of materials), we must always rely on the image improvement techniques (ClearStent or StentBoost) and use short balloons that on the one hand they do not overpass the stent, and on the other hand they do not deform the neocarina; that is why we recommend to cover with stent at least 6-8 mm proximal to the birth of the lateral branch.

The follow-up of the patients was clinical in the month 1 and 6, and angiographic in the month 6. During the follow-up there were suggestive symptoms of ischemic complications and angiographic evidence of thrombosis and restenosis of stent.

The primary end point of this paper was the target vessel failure (TVF) rate, composed by death, infarct (TVMI) and re-intervention need (TLR).

RESULTS

Sixty two patients were included during 2018-2022 (Figure 1), out of which 45 have been controlled in an angiographical way so far. 62.9% out of the total were male, with an average age of 68 years old. The initial clinical presentation was a chronical angina in most of the patients (n=49; 79%), whereas others were acute coronary syndromes (n=13; 21%) but without angiographic evidence of the thrombotic material on zones of bifurcation after implanting a provisional stent, we opt for the anticoagulation and restudy in the following days, provided that there were no commitment of flow in secondary branch. A total of 28 patients (45.2%) presented anatomy 1.1.1 according to Medina classification; 18 patients (29%) presented anatomy 1.1.0, 12 patients (19.3%) of type 1.0.0 and finally 4 patients (6.5%) of type 0.1.1. In all the cases 2 active drug everolimus-eluting stents were implanted, following the steps of TAP technique8,9.The bifurcation most frequently affected was anterior descendent with diagonal branch (n=41; 66;1%), followed by circumflex with marginal branch (n=13;21%), and finally the bifurcation of distal right coronary (n=8; 12,9%). There were no major complications during the process. 7 Fr catheter was used in all the patients. 38.7% (24) was by radial access, without necessity of access change in none of them (Table 1).

During the clinical follow-up of the first month, a patient died three days after the procedure at his domicile (probable thrombosis), and two patients were in hospital again due to acute coronary syndrome (TVMI) with angiographical evidence of stent thrombosis (in both cases it wasdue to thrombosis of proximal edge of stent of main vase). The rest of the patients was asymptomatic during this period. In the follow-up of the sixth month, all the patients sustained double platelet anti-aggregation. There were no new ischemic nor hemorrhagic clinical events.

Regarding the angiographic follow-up of the sixth month, two patients presented significant ostial restenosis of lateral branch which required revascularization (TLR), and other three patients had restenosis less than 50% (by angiographic quantification –AQC) of stent of secondary branch, asymptomatic and without evidence of ischemia in scintigraphy, thus they continued with medical treatment (Table 2).

The primary end point (TVF) occurred in 11% of patients, composed by death 2.2% (1 patient), TVMI 4.4% (2 patients) and TLR guided by ischemia 4.4% (2 patients).

DISCUSSION

If the treatment of bifurcations of coronary arteries is under constant discussion and analysis on big international studies, it is for us equally important the filing and follow-up of patients in our environment in order to know our results and compare them.

The data obtained so far in our filing are encouraging (TVF 6 months: 11% with TAP) when we compare them with international filings such as Smart-Strategy1 (TVF 12 months: 9.2% provisional stenting, 9.4% DK Crush), EBC-TWO2 (TVF 12 months: 10.3% Culotte) or DEFINITION6 (TLF 12 months: 11.4% provisional stenting, 6.1% DK-Crush).

There are numerous techniques to treat coronary bifurcations, each one with a series of steps which must be respected meticulously to achieve the best results and avoid complications during the procedure as well as in the follow-up. We recommend consolidating some of them, especially the ones which best adapt to the personal experience and resources of the equipment. Thus, we would work in a more systematic way, avoiding eventualities that may arise when procedures are made to which one is not used to.

Registries like SMART-STRATEGY1 or EBC-TWO2 recommend TAP as a technique to follow in case a stent in lateral branch is required. We believe this technique can be useful to treat most of the coronary bifurcations due to the fact that it can be used as initial strategy (initial intention technique of two stents) or as alternative in the cases of provisional-stenting which presented ostial commitment of secondary branch, after implanting the stent in main vessel.

It is worthwhile remarking that, from our experience, the TAP technique demands the use of a lower quantity of material during the process as regards other techniques such as Culotte or DK-Crush, which is a determinant factor to optimize resources.

STUDY LIMITATIONS

Firstly, we remark as main limitation the fact of not being able to use the techniques of intravascular images in a systematic way. Some files such as SMART-STRATE-GY1reported the use of intravascular ultrasound (IVUS) in 96.9% of the cases of provisional stent and in 98.5% of the cases of TAP.

Secondly, we remark that for the time being the follow-up is only for six months, compared to the long term follow-ups of the studies mentioned in this paper1,2,5,6 although we will continue adding and controlling patients in order to generate more compelling data.

CONCLUSIONS

The systematic use of TAP for the treatment of coronary arteries bifurcation where the use of two stents is required seems to be an accessible and safe technique in our environment.

SUMMARY OF IMPORTANT POINTS

- Topic under constant discussion and revision.

- Local limitations for the systematic application of some techniques supported on international registries.

- Search of standardization and systematization of strategies accordingtoresourcesofeachcenter.

1. Song YB, Park TK, Hahn J-Y, et al. Optimal Strategy for Provisional Side Branch Intervention in Coronary Bifurcation Lesions: 3-Year Outcomes of the SMART-STRATEGY Randomized Trial. JACC Cardiovasc Interv 2016;9(6):517-26. doi:10.1016/j.jcin.2015.11.037
2. Hildick-Smith D, Behan MW, Lassen JF, et al. The EBC TWO Study (European Bifurcation Coronary TWO): A Randomized Comparison of Provisional T-Stenting versus a Systematic 2 Stent Culotte Strategy in Large Caliber True Bifurcations. Circ Cardiovasc Interv 2016;9(9). doi:10.1161/CIRCINTERVENTIONS.115.003643

3. Banning AP, Lassen JF, Burzotta F, et al. Percutaneous coronary intervention for obstructive bifurcation lesions: the 14th consensus document from the European Bifurcation Club. EuroIntervention 2019;15(1):90-8. doi:10.4244/EIJ-D-19-00144

4. Bin SY, Kyu PT, Joo-Yong H, et al. Optimal Strategy for Provisional Side Branch Intervention in Coronary Bifurcation Lesions. JACC Cardiovasc Interv 2016;9(6):517-26. doi:10.1016/j.jcin.2015.11.037

5. Di Gioia G, Sonck J, Ferenc M, et al. Clinical Outcomes Following Coronary Bifurcation PCI Techniques: A Systematic Review and Network Meta-Analysis Comprising 5,711 Patients. JACC Cardiovasc Interv 2020;13(12):1432-44. doi:https://doi.org/10.1016/j.jcin.2020.03.054.

6. Zhang J-J, Ye F, Xu K, et al. Multicentre, randomized comparison of two-stent and provisional stenting techniques in patients with complex coronary bifurcation lesions: the DEFINITION II trial. Eur Heart J 2020;41(27):2523-36. doi:10.1093/eurheartj/ehaa543.

7. Medina A, de Lezo JS, Pan M. Una clasificación simple de las lesiones coronarias en bifurcación. Rev Española Cardiol 2006;59(2):183. doi:https://doi.org/10.1157/13084649.

8. Burzotta F, Gwon HC, Hahn JY, Romagnoli E, Choi JH, Trani C, Colombo A. Modified T-stenting with intentional protrusion of the side-branch stent within the main vessel stent to ensure ostial coverage and facilitate final kissing balloon: the T-stenting and small protrusion technique (TAP-stenting). Report of bench testing and first clinical Italian-Korean two-centre experience. Catheter Cardiovasc Interv 2007;70:75-82. doi: 10.1002/ccd.21194.

9. Burzotta F, Vladimir D, Miroslaw F, Carlo T, Goran S. Technical aspects of the T and small Protrusion (TAP) technique. EuroIntervention 2015;11:V91-V95. doi: 10.4244/EIJV11SVA20.

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T-and-protrusion technique (TAP) for coronary bifurcation stenting: our experience

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