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https://doi.org/10.47803/rjc.2020.30.3.443

Mihai Melnic1, Flavius Gherasie1, Al Hassan Ali1, Ionut Stanca1, Mihai Santa1, Cristian Girgel1, Adrian Linte1, Serban Balanescu1,2

1 Elias University Emergency Hospital, Bucharest, Romania
2 University of Medicine and Pharmacy „Carol Davila”, Bucharest, Romania

Coronary artery disease (CAD) is a pathological pro-cess characterized by atherosclerotic plaque accumulation in the epicardial arteries, obstructive or non-obstructive. The disease can be stable but can also become unstable at any time, typically due to an acute atherothrombotic event caused by plaque rupture or erosion. New-onset angina is generally regarded as unstable angina. Emergency angiographic evaluation is recommended.
Left main coronary artery disease has a higher prognostic risk as a result of the large myocardial territory at risk, ranging from 75% to 100%, depending on the dominance of the left coronary circulation.
Current clinical practice guidelines from both the American College of Cardiology/American Heart Association and the European Society of Cardiology recommend revascularization for all patients with ≥50% stenosis of the left main coronary artery (LM), regardless of symptomatic status or associated ischemic burden.
Drug-eluting stents are preferred for LM revascu-larization as they offer improved survival and fewer adverse cardiovascular events compared with BMS.
In a study of 57 de novo left main bifurcation (LMB) lesions, TAP stenting with second-generation DES had acceptable TLF rate at 3-year follow-up of 13.3%. In contrast the BBK (Bifurcations Bad Krozingen) II study, where 39% had LM stenting, the Culotte technique compared to TAP had at one year, a TLF of 6.7% vs 12.0% (P = 0.11).
Current practice guidelines in support of revascularization of all LM lesions ≥ 50% are based on older trials in an era when medical therapy was limited and before the use of invasive physiological assessment of stenosis severity. In fact, the same evidence suggests that medical management of patients at lower risk might be associated with favorable outcomes. Although smaller studies support the use of FFR and IVUS to define lower-risk groups with LM disease who could be treated by optimal medical therapy alone, larger trials assessing clinical outcomes over longer follow-up are needed to fully assess this strategy.

MEDICAL MANAGEMENT OF LMCAD
In the COURAGE (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) trial2, similar outcomes were observed for an initial strategy of optimal medical therapy compared with initial revascularization in patients with stable non-LM CAD. The safety of deferred revascularization in patients with stable LM disease is less well known, but current clinical practice guidelines strongly recommend revas-cularization in all patients with ≥50% stenosis of the LM. The basis for these class IA recommendations is predicated on post hoc data derived from subgroup analyses of 185 patients with LM disease from 2 randomized clinical trials (RCTs) of patients with chronic stable angina conducted in the late 1970s and early 1980s3,4 demonstrating the superiority of surgical revascularization over medical therapy on 5- to 10-year survival. These early RCTs were conducted in an era when medical therapy was, by contemporary standards, limited. For example, only 66% of „medically managed” patients with LM in those early trials received -blockers and only 19% were taking aspirin. These trials antedated the current widespread use of disease-modifying pharmacologic interventions (such as statins, inhibitors of the renin-angiotensin-aldosterone system, and more effective antiplatelet agents such as P2Y12 inhibitors), which reduce adverse car-diovascular events in patients with CAD.
Current clinical guidelines strongly recommend surgical revascularization for LMCAD (class IA) with PCI considered a reasonable alternative (class II) in select patients with less complex anatomy (SYNTAX score of <33) and clinical characteristics that predict an increased risk of adverse surgical outcomes. How-ever, patients with PCI need close clinical follow-up, as they may have a higher need for repeat revascularization in the future.

CASE PRESENTATION
A 31 years old male patient with cardiovascular risk factor (mild dyslipidemia) without any prior presentation for cardiovascular disease, is admitted on the Cardiology Department with a diagnosis of de novo angina (unstable angina). The patient describes typical retrosternal pain with radiation on both arms. The current symptoms appeared 2 months ago. The patient also did a a positive ECG stress test (Bruce protocol) on the day of the presentation at Elias Hospital. The general objective examination reveals a stable general condition, normal rhythmic heartbeats without any heart murmurs and no pulmonary or sistemic congestion. The electrocardiogram (Figure 1) performed on admission shows no particular ischemic modifications and the cardiac enzymes value levels are in the normal range. Complete blood count and bio-chemistry laboratory tests are within normal range, with mild dysiidemia (LDL=77 mg/dl, HDL=29mg/dl, TG=163mg/dl). Echocardiography shows a nondilated left ventricle (LV) with preserved systolic function (ejection fraction 60%), with no wall motion abnormalities, no significant valvulopathies, and no signs of pulmonary hypertension.
The patient is transported to the cathlab for emergency coronarography. The coronarography shows the right coronary artery (RCA) without significant stenosis, subocclusion of left main, subocclusion of ostial left anterior descending artery (LAD), 70% steno-sis of the mid segment and subocclusion of the circumflex artery –Medina 1-1-1 bifurcation lesion (Figure 2, 2a the arrows point at the stenosis).
Single stent technique, with or without final kissing balloon inflation, should be preferred over the 2-stent technique, whenever possible, to minimize stent length or stent overlap. The multiple 2-stent techniques need to be utilized, however, when tackling compromised or dissected large side branches. We describe a provisional 2-stent technique, TAP technique, which has the characteristic of minimizing stent overlap at the bifurcation and ensuring good stent coverage at the side branch ostium.
The NORDIC I trial compared a provisional versus planned 2-stent technique with drug-eluting stents. There was only a 2.7% crossover rate to the 2-stent technique in the provisional group, and no difference in MACE between the two groups at 6 months. A 6 Fr lumen EBU 3.5 guiding catheter was chosen, radial approach. Predilatation was performed in the LAD, LCX and left main arteries. A 3.0 x 24 mm DES (Biomatrix alpha – Biosensors) was delivered into the mid left anterior descending artery (LAD) (Figure 3,4), Then a 4.0 x 24 mm DES (Biomatrix alpha – Biosensors) was deployed at high pressure from the left main into the LAD (Figure 5,6), however, the result was suboptimal in the ostial circumflex artery, we manage to re-cross into the circumflex artery.
We performed predilation with a 2.0 x 15mm semicompliant ballon infl ated throught stent struts into the ostium of the circumflex artery. We delivered a 3.5 x 14 mm DES (Biomatrix alpha – Biosensors) that was pulled back 1-2 mm into the left main and inflated at 18 atm (Figure 7,8).
Multiple kissing inflations were performed in the distal left main bifurcation (Figure 9), and finally, POT was performed with a 5.0 x 8 mm noncompliant balloon inflated at 12-14 atm pressures throughout the left main (Figure 10,11a, 11b,11c).
The patient remains anginafree at 4 months post intervention.
Patient was put on medical therapy consisting of ticagrelor 90 mg twice/day, AAS 75 mg once/day, ator-vastatin 80 mg once/day, bisoprolol 5 mg once/ day and pantoprazole 40 mg once/day.

Figure 1. ECG at presentation showing sinus rhythm at 75 beats, no particular ischemic modifications.

Figure 2.                                                                                                                      Figure 2a.

Figure 7. TAP technique.

Figure 7. StentBoost® after final POT.

DISCUSSION
The modification of the T-stenting was first described in 2007 by Burzotta et al1. It was evaluated in vitro and in two independent series of patients undergoing elective drug-eluting stent (DES) implantation on a bifurcation lesion. In vitro testing demonstrated perfect coverage of the bifurcation with minimal stent’s struts overlap at the proximal segment of SB ostium with a single layer stent struts. Sirolimus, paclitaxel, or zotarolimus DES were deployed in 73 patients (67% with Medina 1,1,1 lesions and 44% of unprotected distal left main disease) using the TAP technique. The procedural success was achieved in all cases. At 9 months the clinically-driven target vessel revascularization (TVR) was 6.8%. Since this was a pilot study, the investigators recommended larger outcome trials to further evaluate this technique. It is expected that the results of EXCEL and NOBLE will determine the next guidelines for the foreseeable future, as forthcoming trials of this magnitude are unlikely to be pursued from economic and priority viewpoints unless marked advances in revascularization technologies emerge. Importantly, a heart team approach for shared decision-making should be the standard of care for all cases of LMCAD.

CONCLUSION
In comparison with T-stenting, the TAP technique with kissing balloon inflation and final POT is associated with a reduced rate of restenosis in the side branch.
The TAP technique is a provisional 2-stent technique that involves stenting the main branch, and in the presence of a suboptimal ostial side-branch result, passing a second stent into the side branch with 1–2 protruding into the main, followed of kissing inflation si final POT optimisation.5-12
The benefit of this „TAP” technique (1-2mm over-lap), is that the opportunity to first perform single-stenting is preserved, while side-branch stenting can be performed only if required. This technique would also minimize the overlap of drug-eluting stents, similar to the mini-crush technique, thereby potentially reducing the risk of stent thrombosis.13-21 Recrossing into the side branch in both cases becomes reasonably simple, since with this technique, only one layer of stent needs to be crossed at any given time.

Conflict of interest: none declared.

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