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Dedicated Tryton Side Branch Stents used in the treatment of coronary bifurcation lesions
cor et vasa 56 (2014) e478–e485
Available online at www.sciencedirect.com
ScienceDirect journal homepage: http://www.elsevier.com/locate/crvasa
Original research article
Dedicated Tryton Side Branch Stents used in the treatment of coronary bifurcation lesions L. Pleva a,c,*, T. Jonszta b,1, P. Kukla a,2, J. Zapletalova d,3, P. Berger e,4, J. Mrozek a,2, M. Porzer a,2, B. Obžut a,2 a
Cardiovascular Department, University Hospital Ostrava, Czech Republic Radiagnostic Department, University Hospital Ostrava, Czech Republic c Medical Faculty, University of Ostrava, Czech Republic d Department of Medical Biophysics, Palacky University, Czech Republic e Department of Cardiac Surgery, University Hospital Ostrava, Czech Republic b
article info
abstract
Article history:
Introduction: Coronary bifurcation lesions account for 15–20% of all percutaneous coronary
Received 25 March 2014
interventions.
Received in revised form 27 May 2014 Accepted 5 June 2014 Available online 10 July 2014
Dedicated bifurcation stents have recently been introduced with the aim to simplify treatment and improve early and late outcomes following stenting of bifurcation lesions. The purpose of our study was to assess the safety and effectiveness of the Tryton dedicated side branch stent at a 6-month clinical and angiography follow-up. Methods: Forty-two patients with bifurcation lesions were included in our study. The
Keywords:
primary endpoint was a 6-month MACE and angiographic stent patency was also evaluated
Bifurcation
by MS-CT coronarography.
Tryton Side Branch Stent
Results: Twenty-two patients (52.38%) were treated for acute coronary syndromes, 39 (92.85%)
MS-CT coronarography
lesions were ‘‘true bifurcations’’. The 6-month clinical follow-up was performed in all patients. The 6-month MACE rate (cardiac death, myocardial infarction and target lesion revascularization) was 9.52% (95% CI: 2.66–22.62%); of these one patient (2.38%; 95% CI: 0.06–12.57%) died
* Corresponding author at: Cardiovascular Department, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava-Poruba, Czech Republic. Tel.: +420 733414740. E-mail addresses: [email protected] (L. Pleva), [email protected] (T. Jonszta), [email protected] (P. Kukla), [email protected] (J. Zapletalova), [email protected] (P. Berger), [email protected] (J. Mrozek), [email protected] (M. Porzer), [email protected] (B. Obžut). 1 Address: Radiagnostic Department, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava-Poruba, Czech Republic. Tel.: +420 597372172. 2 Address: Cardiovascular Department, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava-Poruba, Czech Republic. Tel.: +420 7373216. 3 Address: Department of Medical Biophysics, Palacky University, Hněvotínská 3, 775 15 Olomouc, Czech Republic. Tel.: +420 58 563 2712. 4 Address: Department of Cardiac Surgery, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava-Poruba, Czech Republic. Tel.: +420 7373216. Abbreviations: MS-CT, multi-slice CT coronarography; MIP, maximum intensity projection; PCI, percutaneous coronary intervention; MACE, major adverse cardiovascular events; ISR, in-stent restenosis; TVR, target vessel revascularization; LM, left main stem; LAD, left anterior descending artery; RD, diagonal branch; LCx, left circumflex artery; OM, obtuse marginal branch; RCA, right coronary artery; PDA, posterior descending artery; SB, side branch; RAO, right anterior oblique view; LAO, left anterior oblique view. http://dx.doi.org/10.1016/j.crvasa.2014.06.001 0010-8650/# 2014 The Czech Society of Cardiology. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
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due to cardiogenic shock caused by early stent thrombosis and three patients (7.14%; 95% CI: 1.50–19.48%) required repeated revascularization (TVR) due to in-stent restenosis, all of them in bare metal stents. Tryton stent implantation was successful in 100% lesions. 6-Month MS-CT coronarography was performed in 39 (92.85%) patients. The implanted bifurcation Tryton stents were satisfactorily visualized in 97.43% of them and a satisfactory 6-month angiographic patency was demonstrated in 37 patients (88.1%). Conclusion: The usage of a dedicated bifurcation Tryton Side Branch Stent for PCI of the bifurcation lesions is technically feasible with satisfactory long-term results. # 2014 The Czech Society of Cardiology. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
Introduction
Methods
Coronary bifurcation lesions account for 15–20% of all percutaneous coronary interventions [1]. When compared to non-bifurcation lesions, this lesion subset is considered complex to treat, with inferior angiographic and clinical results (acutely and at follow-up) [2]. Dedicated bifurcation stents have recently been introduced with the aim to simplify treatment and improve early and late outcomes following stenting of bifurcation lesions. When compared to the ‘‘classical’’ culotte technique, the Tryton makes the procedure easier [3]. We aimed to assess in a prospective single-center registry, safety and effectiveness at 6-month clinical and angiography follow-up of the Tryton dedicated side branch stent.
Patient population Patients with bifurcation lesions in whom a dedicated Tryton Side Branch Stent was implanted at our Department during 2010–2013 were included in our registry. The primary endpoint was a 6-month major adverse cardiovascular events rate (MACE; cardiac death, myocardial infarction and target lesion revascularization) and angiographic stent patency was also evaluated by MS-CT coronarography.
Tryton device The Tryton Side Branch Stent (Tryton Medical, USA), which was used by us, is a chromium–cobalt stent consisting of three parts: the distal segment is a common stent for implantation in the
Fig. 1 – Case 1, tight bifurcation stenosis Medina 1,1,1 at proximal LAD and Dx1. (A) Left anterior oblique 458, caudal 458 view; (B) right anterior oblique 258, cranial 408 view.
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cor et vasa 56 (2014) 478–485
lateral branches; the middle or ‘‘thin’’ transitional segment; and the proximal segment to fit in the main branch. The stent allows simple performance of the ‘‘reverse culotte technique’’ [4].
Interventional procedure Coronary intervention was performed at the Siemens Axiom device (Forcheim, Germany) by the standard method from the right or left radial approach using the 6F guiding catheters. After wiring of both the main vessel and the side branch and predilation, the Tryton Side Branch Stent is advanced
over the wire into the side branch, and using the two middle markers on the delivery system, the stent is positioned till these markers straddle the side branch origin. Deployment of the stent is followed by retraction of the guidewire from the side branch and repositioning it through the fronds of the transition zone into the distal main vessel. A standard stent is then advanced and positioned in the main vessel jailing the stented side branch. Once the main vessel stent is deployed re-crossing into the side branch allows final kissing balloon inflation [4] (Figs. 1–6).
Fig. 2 – Process of dedicated Tryton stent implantation, right anterior oblique 258, cranial 408 view: (A) Tryton stent placement; (B) Tryton stent implantation; (C) final kissing postdilation.
cor et vasa 56 (2014) e478–e485
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Fig. 3 – Case 1, final results. (A) Right anterior oblique 258, cranial 408 view; (B) left anterior oblique 208, cranial 408 view.
Follow-up
Multi-slice CT coronarography
The patients received standard dual antiaggregation therapy (clopidogrel 75 mg and ASA 100 mg/day), beta-blockers and statins, with 6-month follow-up. Clinical examination was performed, any MACE were recorded and MS-CT coronarography was performed.
All patients were examined without the need of previous premedication with beta-blockers in the Siemens Somatom Definition AS+ device (Forcheim, Germany). It is a single source CT scanner in a 128-slice configuration. The scanning mode cardiacCT (CT Syngo 2011) with retrospective ECG gating was
Fig. 4 – Case 2, tight bifurcation stenosis Medina 1,1,1 at proximal LAD and Dx1. (A) Left anterior oblique 208, cranial 408 view; (B) left anterior oblique 458, caudal 458 view.
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Table 1 – Demographic characteristics. Age Male Female Diabetes mellitus Renal failure Ejection fraction (%) CABG
62.85 9.9 35 (83.33%) 7 (16.67%) 11 (26.19%) 1 (2.38%) 53.55 9.27 1 (2.38%)
MIP and automatic software Vessel analysis were used for evaluation of the lumen (Fig. 7).
Statistical analysis Continuous variables are presented as means standard deviations; categorical variables are presented as counts and percentages. For the most important endpoints of the study, 95% confidence intervals of the single point estimates were calculated using the dedicated software Statistica 12 (StatSoft, OK, USA).
Results Fig. 5 – Tryton stent implantation, left anterior oblique 458, caudal 458 view.
used for examination of coronary arteries. The acquired data were reconstructed in various phases of cardiac cycle to minimize the movement artifacts in the stents. Evaluation in the soft and hard kernel (B30f, B46f) was used for each stent to reduce the effects of the artifacts. The final scans including evaluation of the in-stent restenosis grade were performed using the reconstruction software Aquarious iNTUITION (Tera Recon, Foster City, CA, USA). The MIP reconstructions, curved
A total of 42 patients with bifurcation lesions were included in our registry. The group's demographic data are presented in Table 1. Twenty-two patients (52.38%) were treated for acute coronary syndromes; one patient with critical stenosis of the distal left main stem was in cardiogenic shock. Thirty-nine (92.85%) lesions were ‘‘true bifurcations’’ (Medina 1,1,1; 1,0,1 and 0,1,1). The characteristics and locations of the lesions are presented in Table 2 and Graph 1. The mean diameters (SD) of the proximal and distal segments of the main branch and the side branch were
Fig. 6 – Case 2, final results. (A) Right anterior oblique 258, cranial 408 view; (B) left anterior oblique 458, caudal 458 view.
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Lession localisation LM dist 1 (2,4%) SVG 1 (2,4%) RCA x PDA x PDL 4 (9,5%) LM dist LAD x Dx
LCX x OM 2 (4,8%)
LCX x OM RCA x PDA x PDL SVG
LAD x RD 34 (80,9%)
Graph 1
Fig. 7 – 6-Month follow-up; MS-CT volume-rendered 3-D image; patent Tryton stent.
3.55 0.28, 3.35 0.39 and 2.75 0.37 mm, respectively; hence, bifurcation lesions with significant side branches were involved. The mean lesion length in the main branch was 24.5 7.06 mm. The sizes of the Tryton stents are shown in Graph 2. A drug eluting stent as a second stent was implanted in the main branch in 54.8% of the cases. In one case, implantation of a bare metal stent was preceded by predilation with a drug eluting balloon catheter due to the need for early non-cardiac surgery. Due to the length of the lesion or to existing edge dissection, another stent was implanted into the side branch in 6 (14.3%) cases and into the main branch in 4 (9.5%) cases. Tryton stent implantation was successful in 100% of the lesions. The stent was distorted during the procedure in one case; the next Tryton stent was smoothly introduced following repeated predilation. In one case, presumably due to aggressive final kissing postdilation, paravasal leak of the contrast
agent was apparent, however, without development of the hemopericardium or need for pericardiocentesis. Final kissing postdilation was performed in 100% of the lesions. The 6-month clinical follow-up was performed in all patients. The 6-month MACE rate (cardiac death, myocardial infarction and target lesion revascularization) was 9.52% (95% CI: 2.66–22.62%). One patient (2.38%; 95% CI: 0.06–12.57%) died of a cardiogenic shock caused by early stent thrombosis. Three patients (7.14%; 95% CI: 1.50–19.48%) required repeated revascularization (TVR) due to in-stent restenosis, all of them arise in bare metal stents. Furthermore, one non-cardial death due to generalized lung cancer was recorded. Thirty-six (85.71%) patients were without limiting effort angina pectoris (CCS class 0–1). A 6-month MS-CT coronarography was performed in 39 (92.85%) patients. The implanted bifurcation Tryton stents were satisfactorily visualized in 38 of them (97.43%); one small side branch (2.5 mm) of the Tryton stent was not evaluable due to blooming artifacts. The above-mentioned in-stent restenosis was detected in one patient, requiring subsequent rePCI. The remaining 37 implanted Tryton stents (88.1%) demonstrated satisfactory 6-month angiographic patency by MS-CT.
Tryton stents 5 (12%)
1 (2%)
22 (53%) 5 (12%) 3,5/2,5x19 3,5/3x18 3/2,5x19
Table 2 – Lesion characteristics.
4/3,5x18
Medina classification 1,1,1 0,1,1 1,1,0 0,0,1
33 6 2 1
(78.57%) (14.28%) (4.76%) (2.38%)
4/3,5x15
9 (21%)
Graph 2
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Discussion Many strategies have been evaluated in the treatment of coronary bifurcation lesions. In the NORDIC study a total of 413 patients with a bifurcation lesion were randomized to compare a strategy of stenting both the main vessel and the side branch with a strategy of stenting the main vessel only (and optional stenting of the side branch) using sirolimus-eluting stents. In the main vessel + side branch group several different techniques were used (culotte, crush, T-stenting, etc.). In this trial a very low rate of major adverse cardiovascular events was seen in both groups at 6-month follow-up with no significant difference (2.9% vs. 3.4%, NS) [5]. In the BBC ONE study, 500 patients with bifurcation lesions were randomized to either a provisional T-stent strategy or full lesion coverage with either culotte or crush technique. A significant difference was observed between the MACE rates in the complex group vs. that in the simple group (15% vs. 8%, P = 0.009). This was largely driven by a higher incidence of periprocedural myocardial infarction in the complex group [6]. In the CACTUS study 350 patients with coronary bifurcations were randomized to crush or provisional T-stenting using sirolimus stents. Kissing balloon inflations were mandated in both groups, and were achieved in above 90%. The primary clinical endpoint (6-month MACE) was similar in the two groups (16% vs. 15%, P = NS), and there was no difference in the rate of angiographic restenosis in either the main or side branch [7]. According to the consensus of the European Bifurcation Club, nowadays provisional T-stenting is considered the golden standard of treatment for most bifurcation lesions. Stent implantation into a side branch (SB) is only required if a significant impairment of its ostia persists following the final kissing postdilation (dissection, residual stenosis greater than 75%, TIMI flow class below 3 in SB ≥ 2.5 mm or FFR below 0.75). In contrast, bifurcation lesions with involvement of a large SB, which exceeds 5 mm from the carina, usually primarily require the implantation of two stents. In this case the culotte technique brings some advantages over the crush technique (significantly lower periprocedural AMI and ISR) [8,9]. In a real world the use of the Tryton Side Branch Stent was studied in two registries. In the E-Tryton registry, 302 patients with coronary bifurcation lesions underwent treatment with the Tryton stent, in conjunction with a main branch stent (drug-eluting in 88% cases). Procedural success occurred in 94% patients. The primary endpoint, 6-month MACE (cardiac death, myocardial infarction and target lesion revascularization) rate was 6.4%, including 4.7% myocardial infarctions (3.7% periprocedural) and 3.4% target lesion revascularizations and 1 stent thrombosis (0.3%) [10]. In the Rotterdam–Poznan registry there were 96 patients with 100 lesions included. Procedural success rate reached 94%. At a 6-month follow-up, TVR rate was 4%, MI 3%, and cardiac death 1%. The percentage MACE-free survival at 6 months was 94%. Both these registries show that the treatment of bifurcation lesions with a dedicated Tryton stent is safe and feasible, with
good technical and procedural success and low major adverse cardiac events at 6-month clinical follow-up [11]. Thirty-nine (92.85%) lesions in our study group were ‘‘true bifurcations’’. The true bifurcation lesions are reported to lesions involving the main branch and ostium of the side branch (Medina 1,1,1; 1,0,1 and 0,1,1). In comparison with the above-mentioned registries, our patients constituted a higher-risk group, with a larger proportion of acute coronary syndromes (55 3% and 24.5%). One patient died due to early stent thrombosis after implantation of a bifurcation and drug eluting stent into the LM for acute myocardial infarction complicated by a cardiogenic shock, in possible relation with temporarily ineffective antiaggregation due to a bleeding stress ulcer. Repeated target vessel revascularization (TVR) was necessary in three patients (7.14%), in all cases due to in-stent restenosis (ISR) in the second bare metal stent. The in-stent restenosis was clinically manifested as a relapse of effort angina pectoris and was treated by drug eluting balloon catheters, with persisting satisfactory results (no additional 6-month MACE). The relatively large fraction of bare metal stents implanted in the main branch in our patient group was primarily due to the impossibility of long-term dual antiaggregation in such patients (urgent non-cardial surgery, risk of bleeding from the gastrointestinal tract, necessity of permanent anticoagulation due to artificial heart valve or for an atrial fibrillation with a recent cardioembolic stroke). In one patient the Tryton stent was successfully implanted into the bifurcation lesion on a Y-shaped vein graft, which gave rise to an interesting case study [12]. Duration of dual antiplatelet therapy after the Tryton stent implantation is mostly influenced by the type of the second stent implanted into the main vessel, with respect to the preferred use of DES dual antiplatelet therapy administered for 6–12 months. We used multi-slice CT coronary angiography to demonstrate the long-term patency of the implanted stents. Usage of CT coronarography in the demonstration of in-stent restenoses was assessed by Sun in his meta-analysis. The sensitivity and specificity of the 64-slice CT angiography in the detection of in-stent restenoses were 90% and 91%, respectively. The mean value of assessable stents was 89– 91%. Significantly higher diagnostic success was achieved during the evaluation of stents with the diameter greater than 3 mm (in comparison with stents under 2.75 or 2.5 mm) [13]. Our own data from another study also show that MS-CT coronarography is able to detect coronary in-stent restenosis with sufficient reliability (with sensitivity 80% and specificity 97.1%; 94.1% positive and 89.2% negative predictive values) [14]. A major obstacle of the stent lumen visualization is artifacts caused by the dense stent material. Although imaging of two overlapping stents by MS-CT coronarography is difficult, we achieved satisfactory visualization in 97.43% of bifurcation stents.
Conclusion The use of a dedicated bifurcation Tryton Side Branch Stent for PCI of the bifurcation lesions is technically feasible with satisfactory long-term results. This type of stent is beneficial
cor et vasa 56 (2014) e478–e485
especially in the treatment of bifurcation lesions with involvement of a large SB, which exceeds 5 mm from the carina that usually primarily require the implantation of two stents [8,9]. MS-CT coronarography is a reliable method of stent imaging event if two overlapping stents are to be visualized.
Conflict of interest The authors hereby declare that there is no conflict of interest concerning the work published in their study.
Funding body This article was co-supported by the project of the European Social Fund and the State Budget of the Czech Republic, registration number CZ.1.07/2.3.00/20.0040.
Ethical statement The authors hereby declare that the principles of publication ethics were followed during our manuscript preparation.
Informed consent The authors hereby declare that the patients gave the informed consent for the publication of their findings and results.
references
[1] B. Meier, A.R. Gruentzig, S.B. King 3rd, et al., Risk of side branch occlusion during coronary angioplasty, The American Journal of Cardiology 53 (1984) 10–14. [2] I. Iakovou, L. Ge, A. Colombo, Contemporary stent treatment of coronary bifurcations, Journal of the American College of Cardiology 46 (2005) 1446–1455. [3] P. Agostoni, D. Foley, M. Lesiak, A prospective multicentre registry, evaluating real-world usage of the Tryton side branch stent: results of the E-Tryton 150/Benelux registry, EuroIntervention 7 (2012) 1293–1300.
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[4] M. Magro, J. Wykrzykowska, P.W. Serruys, C. Simsek, S. Nauta, M. Lesiak, et al., The Tryton Side Branch Stent, EuroIntervention Supplement 6 (Suppl. J) (2010) J147–J150. [5] T.K. Steigen, M. Maeng, R. Wiseth, A. Erglis, I. Kumsars, I. Narbute, et al., Randomized study on simple versus complex stenting of coronary artery bifurcation lesions: the Nordic bifurcation study, Circulation 114 (2006) 1955– 1961. [6] D. Hildick-Smith, A.J. de Belder, N. Cooter, N.P. Curzen, T.C. Clayton, K.G. Oldroyd, et al., Randomized trial of simple versus complex drug-eluting stenting for bifurcation lesions: the British Bifurcation Coronary Study: old, new, and evolving strategies, Circulation 121 (2010) 1235–1243. [7] A. Colombo, E. Bramucci, S. Saccà, R. Violini, C. Lettieri, R. Zanini, et al., Randomized study of the crush technique versus provisional side-branch stenting in true coronary bifurcations: the CACTUS (Coronary Bifurcations: Application of the Crushing Technique Using SirolimusEluting Stents) Study, Circulation 119 (2009) 71–78. [8] G. Stankovic, O. Darremont, M. Ferenc, D. Hildick-Smith, Y. Louvard, R. Albiero, et al., Percutaneous coronary intervention for bifurcation lesions: 2008 consensus document from the fourth meeting of the European Bifurcation Club, EuroIntervention 5 (2009) 39–49. [9] D. Hildick-Smith, J. Lassen, R. Albiero, T. Lefèvre, O. Darremont, M. Pan, et al., Consensus from the 5th European Bifurcation Club meeting, EuroIntervention 6 (2010) 34–38. [10] P. Agostoni, D. Foley, M. Lesiak, A. Belkacemi, J. Dens, I. Kumsars, et al., A prospective multicentre registry, evaluating real-world usage of the Tryton side branch stent: results of the E-Tryton 150/Benelux registry, EuroIntervention 7 (2012) 1293–1300. [11] M. Magro, J. Wykrzykowska, P.W. Serruys, C. Simsek, S. Nauta, M. Lesiak, et al., Six-month clinical follow-up of the Tryton side branch stent for the treatment of bifurcation lesions: a two center registry analysis, Catheterization and Cardiovascular Interventions 77 (2011) 798–806. [12] L. Pleva, T. Jonszta, P. Kukla, Percutaneous coronary angioplasty of a bifurcation lesion in the Y saphenous vein graft, Cor et Vasa (2013), http://dx.doi.org/10.1016/j. crvasa.2013.07.008 (cited 25.03.14; online). [13] Z. Sun, A.M. Almutairi, Diagnostic accuracy of 64 multislice CT angiography in the assessment of coronary in-stent restenosis: a meta-analysis, European Journal of Radiology 73 (February (2)) (2010) 266–273. [14] L. Pleva, T. Jonszta, P. Kukla, J. Zapletalova, Multi-slice CT coronarography for detection of in-stent restenosis, in: XXIInd Congress of Czech Society of Cardiology, 2014 (abstract).
Available online at www.sciencedirect.com
ScienceDirect journal homepage: http://www.elsevier.com/locate/crvasa
Original research article
Dedicated Tryton Side Branch Stents used in the treatment of coronary bifurcation lesions L. Pleva a,c,*, T. Jonszta b,1, P. Kukla a,2, J. Zapletalova d,3, P. Berger e,4, J. Mrozek a,2, M. Porzer a,2, B. Obžut a,2 a
Cardiovascular Department, University Hospital Ostrava, Czech Republic Radiagnostic Department, University Hospital Ostrava, Czech Republic c Medical Faculty, University of Ostrava, Czech Republic d Department of Medical Biophysics, Palacky University, Czech Republic e Department of Cardiac Surgery, University Hospital Ostrava, Czech Republic b
article info
abstract
Article history:
Introduction: Coronary bifurcation lesions account for 15–20% of all percutaneous coronary
Received 25 March 2014
interventions.
Received in revised form 27 May 2014 Accepted 5 June 2014 Available online 10 July 2014
Dedicated bifurcation stents have recently been introduced with the aim to simplify treatment and improve early and late outcomes following stenting of bifurcation lesions. The purpose of our study was to assess the safety and effectiveness of the Tryton dedicated side branch stent at a 6-month clinical and angiography follow-up. Methods: Forty-two patients with bifurcation lesions were included in our study. The
Keywords:
primary endpoint was a 6-month MACE and angiographic stent patency was also evaluated
Bifurcation
by MS-CT coronarography.
Tryton Side Branch Stent
Results: Twenty-two patients (52.38%) were treated for acute coronary syndromes, 39 (92.85%)
MS-CT coronarography
lesions were ‘‘true bifurcations’’. The 6-month clinical follow-up was performed in all patients. The 6-month MACE rate (cardiac death, myocardial infarction and target lesion revascularization) was 9.52% (95% CI: 2.66–22.62%); of these one patient (2.38%; 95% CI: 0.06–12.57%) died
* Corresponding author at: Cardiovascular Department, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava-Poruba, Czech Republic. Tel.: +420 733414740. E-mail addresses: [email protected] (L. Pleva), [email protected] (T. Jonszta), [email protected] (P. Kukla), [email protected] (J. Zapletalova), [email protected] (P. Berger), [email protected] (J. Mrozek), [email protected] (M. Porzer), [email protected] (B. Obžut). 1 Address: Radiagnostic Department, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava-Poruba, Czech Republic. Tel.: +420 597372172. 2 Address: Cardiovascular Department, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava-Poruba, Czech Republic. Tel.: +420 7373216. 3 Address: Department of Medical Biophysics, Palacky University, Hněvotínská 3, 775 15 Olomouc, Czech Republic. Tel.: +420 58 563 2712. 4 Address: Department of Cardiac Surgery, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava-Poruba, Czech Republic. Tel.: +420 7373216. Abbreviations: MS-CT, multi-slice CT coronarography; MIP, maximum intensity projection; PCI, percutaneous coronary intervention; MACE, major adverse cardiovascular events; ISR, in-stent restenosis; TVR, target vessel revascularization; LM, left main stem; LAD, left anterior descending artery; RD, diagonal branch; LCx, left circumflex artery; OM, obtuse marginal branch; RCA, right coronary artery; PDA, posterior descending artery; SB, side branch; RAO, right anterior oblique view; LAO, left anterior oblique view. http://dx.doi.org/10.1016/j.crvasa.2014.06.001 0010-8650/# 2014 The Czech Society of Cardiology. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
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due to cardiogenic shock caused by early stent thrombosis and three patients (7.14%; 95% CI: 1.50–19.48%) required repeated revascularization (TVR) due to in-stent restenosis, all of them in bare metal stents. Tryton stent implantation was successful in 100% lesions. 6-Month MS-CT coronarography was performed in 39 (92.85%) patients. The implanted bifurcation Tryton stents were satisfactorily visualized in 97.43% of them and a satisfactory 6-month angiographic patency was demonstrated in 37 patients (88.1%). Conclusion: The usage of a dedicated bifurcation Tryton Side Branch Stent for PCI of the bifurcation lesions is technically feasible with satisfactory long-term results. # 2014 The Czech Society of Cardiology. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
Introduction
Methods
Coronary bifurcation lesions account for 15–20% of all percutaneous coronary interventions [1]. When compared to non-bifurcation lesions, this lesion subset is considered complex to treat, with inferior angiographic and clinical results (acutely and at follow-up) [2]. Dedicated bifurcation stents have recently been introduced with the aim to simplify treatment and improve early and late outcomes following stenting of bifurcation lesions. When compared to the ‘‘classical’’ culotte technique, the Tryton makes the procedure easier [3]. We aimed to assess in a prospective single-center registry, safety and effectiveness at 6-month clinical and angiography follow-up of the Tryton dedicated side branch stent.
Patient population Patients with bifurcation lesions in whom a dedicated Tryton Side Branch Stent was implanted at our Department during 2010–2013 were included in our registry. The primary endpoint was a 6-month major adverse cardiovascular events rate (MACE; cardiac death, myocardial infarction and target lesion revascularization) and angiographic stent patency was also evaluated by MS-CT coronarography.
Tryton device The Tryton Side Branch Stent (Tryton Medical, USA), which was used by us, is a chromium–cobalt stent consisting of three parts: the distal segment is a common stent for implantation in the
Fig. 1 – Case 1, tight bifurcation stenosis Medina 1,1,1 at proximal LAD and Dx1. (A) Left anterior oblique 458, caudal 458 view; (B) right anterior oblique 258, cranial 408 view.
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cor et vasa 56 (2014) 478–485
lateral branches; the middle or ‘‘thin’’ transitional segment; and the proximal segment to fit in the main branch. The stent allows simple performance of the ‘‘reverse culotte technique’’ [4].
Interventional procedure Coronary intervention was performed at the Siemens Axiom device (Forcheim, Germany) by the standard method from the right or left radial approach using the 6F guiding catheters. After wiring of both the main vessel and the side branch and predilation, the Tryton Side Branch Stent is advanced
over the wire into the side branch, and using the two middle markers on the delivery system, the stent is positioned till these markers straddle the side branch origin. Deployment of the stent is followed by retraction of the guidewire from the side branch and repositioning it through the fronds of the transition zone into the distal main vessel. A standard stent is then advanced and positioned in the main vessel jailing the stented side branch. Once the main vessel stent is deployed re-crossing into the side branch allows final kissing balloon inflation [4] (Figs. 1–6).
Fig. 2 – Process of dedicated Tryton stent implantation, right anterior oblique 258, cranial 408 view: (A) Tryton stent placement; (B) Tryton stent implantation; (C) final kissing postdilation.
cor et vasa 56 (2014) e478–e485
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Fig. 3 – Case 1, final results. (A) Right anterior oblique 258, cranial 408 view; (B) left anterior oblique 208, cranial 408 view.
Follow-up
Multi-slice CT coronarography
The patients received standard dual antiaggregation therapy (clopidogrel 75 mg and ASA 100 mg/day), beta-blockers and statins, with 6-month follow-up. Clinical examination was performed, any MACE were recorded and MS-CT coronarography was performed.
All patients were examined without the need of previous premedication with beta-blockers in the Siemens Somatom Definition AS+ device (Forcheim, Germany). It is a single source CT scanner in a 128-slice configuration. The scanning mode cardiacCT (CT Syngo 2011) with retrospective ECG gating was
Fig. 4 – Case 2, tight bifurcation stenosis Medina 1,1,1 at proximal LAD and Dx1. (A) Left anterior oblique 208, cranial 408 view; (B) left anterior oblique 458, caudal 458 view.
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Table 1 – Demographic characteristics. Age Male Female Diabetes mellitus Renal failure Ejection fraction (%) CABG
62.85 9.9 35 (83.33%) 7 (16.67%) 11 (26.19%) 1 (2.38%) 53.55 9.27 1 (2.38%)
MIP and automatic software Vessel analysis were used for evaluation of the lumen (Fig. 7).
Statistical analysis Continuous variables are presented as means standard deviations; categorical variables are presented as counts and percentages. For the most important endpoints of the study, 95% confidence intervals of the single point estimates were calculated using the dedicated software Statistica 12 (StatSoft, OK, USA).
Results Fig. 5 – Tryton stent implantation, left anterior oblique 458, caudal 458 view.
used for examination of coronary arteries. The acquired data were reconstructed in various phases of cardiac cycle to minimize the movement artifacts in the stents. Evaluation in the soft and hard kernel (B30f, B46f) was used for each stent to reduce the effects of the artifacts. The final scans including evaluation of the in-stent restenosis grade were performed using the reconstruction software Aquarious iNTUITION (Tera Recon, Foster City, CA, USA). The MIP reconstructions, curved
A total of 42 patients with bifurcation lesions were included in our registry. The group's demographic data are presented in Table 1. Twenty-two patients (52.38%) were treated for acute coronary syndromes; one patient with critical stenosis of the distal left main stem was in cardiogenic shock. Thirty-nine (92.85%) lesions were ‘‘true bifurcations’’ (Medina 1,1,1; 1,0,1 and 0,1,1). The characteristics and locations of the lesions are presented in Table 2 and Graph 1. The mean diameters (SD) of the proximal and distal segments of the main branch and the side branch were
Fig. 6 – Case 2, final results. (A) Right anterior oblique 258, cranial 408 view; (B) left anterior oblique 458, caudal 458 view.
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Lession localisation LM dist 1 (2,4%) SVG 1 (2,4%) RCA x PDA x PDL 4 (9,5%) LM dist LAD x Dx
LCX x OM 2 (4,8%)
LCX x OM RCA x PDA x PDL SVG
LAD x RD 34 (80,9%)
Graph 1
Fig. 7 – 6-Month follow-up; MS-CT volume-rendered 3-D image; patent Tryton stent.
3.55 0.28, 3.35 0.39 and 2.75 0.37 mm, respectively; hence, bifurcation lesions with significant side branches were involved. The mean lesion length in the main branch was 24.5 7.06 mm. The sizes of the Tryton stents are shown in Graph 2. A drug eluting stent as a second stent was implanted in the main branch in 54.8% of the cases. In one case, implantation of a bare metal stent was preceded by predilation with a drug eluting balloon catheter due to the need for early non-cardiac surgery. Due to the length of the lesion or to existing edge dissection, another stent was implanted into the side branch in 6 (14.3%) cases and into the main branch in 4 (9.5%) cases. Tryton stent implantation was successful in 100% of the lesions. The stent was distorted during the procedure in one case; the next Tryton stent was smoothly introduced following repeated predilation. In one case, presumably due to aggressive final kissing postdilation, paravasal leak of the contrast
agent was apparent, however, without development of the hemopericardium or need for pericardiocentesis. Final kissing postdilation was performed in 100% of the lesions. The 6-month clinical follow-up was performed in all patients. The 6-month MACE rate (cardiac death, myocardial infarction and target lesion revascularization) was 9.52% (95% CI: 2.66–22.62%). One patient (2.38%; 95% CI: 0.06–12.57%) died of a cardiogenic shock caused by early stent thrombosis. Three patients (7.14%; 95% CI: 1.50–19.48%) required repeated revascularization (TVR) due to in-stent restenosis, all of them arise in bare metal stents. Furthermore, one non-cardial death due to generalized lung cancer was recorded. Thirty-six (85.71%) patients were without limiting effort angina pectoris (CCS class 0–1). A 6-month MS-CT coronarography was performed in 39 (92.85%) patients. The implanted bifurcation Tryton stents were satisfactorily visualized in 38 of them (97.43%); one small side branch (2.5 mm) of the Tryton stent was not evaluable due to blooming artifacts. The above-mentioned in-stent restenosis was detected in one patient, requiring subsequent rePCI. The remaining 37 implanted Tryton stents (88.1%) demonstrated satisfactory 6-month angiographic patency by MS-CT.
Tryton stents 5 (12%)
1 (2%)
22 (53%) 5 (12%) 3,5/2,5x19 3,5/3x18 3/2,5x19
Table 2 – Lesion characteristics.
4/3,5x18
Medina classification 1,1,1 0,1,1 1,1,0 0,0,1
33 6 2 1
(78.57%) (14.28%) (4.76%) (2.38%)
4/3,5x15
9 (21%)
Graph 2
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Discussion Many strategies have been evaluated in the treatment of coronary bifurcation lesions. In the NORDIC study a total of 413 patients with a bifurcation lesion were randomized to compare a strategy of stenting both the main vessel and the side branch with a strategy of stenting the main vessel only (and optional stenting of the side branch) using sirolimus-eluting stents. In the main vessel + side branch group several different techniques were used (culotte, crush, T-stenting, etc.). In this trial a very low rate of major adverse cardiovascular events was seen in both groups at 6-month follow-up with no significant difference (2.9% vs. 3.4%, NS) [5]. In the BBC ONE study, 500 patients with bifurcation lesions were randomized to either a provisional T-stent strategy or full lesion coverage with either culotte or crush technique. A significant difference was observed between the MACE rates in the complex group vs. that in the simple group (15% vs. 8%, P = 0.009). This was largely driven by a higher incidence of periprocedural myocardial infarction in the complex group [6]. In the CACTUS study 350 patients with coronary bifurcations were randomized to crush or provisional T-stenting using sirolimus stents. Kissing balloon inflations were mandated in both groups, and were achieved in above 90%. The primary clinical endpoint (6-month MACE) was similar in the two groups (16% vs. 15%, P = NS), and there was no difference in the rate of angiographic restenosis in either the main or side branch [7]. According to the consensus of the European Bifurcation Club, nowadays provisional T-stenting is considered the golden standard of treatment for most bifurcation lesions. Stent implantation into a side branch (SB) is only required if a significant impairment of its ostia persists following the final kissing postdilation (dissection, residual stenosis greater than 75%, TIMI flow class below 3 in SB ≥ 2.5 mm or FFR below 0.75). In contrast, bifurcation lesions with involvement of a large SB, which exceeds 5 mm from the carina, usually primarily require the implantation of two stents. In this case the culotte technique brings some advantages over the crush technique (significantly lower periprocedural AMI and ISR) [8,9]. In a real world the use of the Tryton Side Branch Stent was studied in two registries. In the E-Tryton registry, 302 patients with coronary bifurcation lesions underwent treatment with the Tryton stent, in conjunction with a main branch stent (drug-eluting in 88% cases). Procedural success occurred in 94% patients. The primary endpoint, 6-month MACE (cardiac death, myocardial infarction and target lesion revascularization) rate was 6.4%, including 4.7% myocardial infarctions (3.7% periprocedural) and 3.4% target lesion revascularizations and 1 stent thrombosis (0.3%) [10]. In the Rotterdam–Poznan registry there were 96 patients with 100 lesions included. Procedural success rate reached 94%. At a 6-month follow-up, TVR rate was 4%, MI 3%, and cardiac death 1%. The percentage MACE-free survival at 6 months was 94%. Both these registries show that the treatment of bifurcation lesions with a dedicated Tryton stent is safe and feasible, with
good technical and procedural success and low major adverse cardiac events at 6-month clinical follow-up [11]. Thirty-nine (92.85%) lesions in our study group were ‘‘true bifurcations’’. The true bifurcation lesions are reported to lesions involving the main branch and ostium of the side branch (Medina 1,1,1; 1,0,1 and 0,1,1). In comparison with the above-mentioned registries, our patients constituted a higher-risk group, with a larger proportion of acute coronary syndromes (55 3% and 24.5%). One patient died due to early stent thrombosis after implantation of a bifurcation and drug eluting stent into the LM for acute myocardial infarction complicated by a cardiogenic shock, in possible relation with temporarily ineffective antiaggregation due to a bleeding stress ulcer. Repeated target vessel revascularization (TVR) was necessary in three patients (7.14%), in all cases due to in-stent restenosis (ISR) in the second bare metal stent. The in-stent restenosis was clinically manifested as a relapse of effort angina pectoris and was treated by drug eluting balloon catheters, with persisting satisfactory results (no additional 6-month MACE). The relatively large fraction of bare metal stents implanted in the main branch in our patient group was primarily due to the impossibility of long-term dual antiaggregation in such patients (urgent non-cardial surgery, risk of bleeding from the gastrointestinal tract, necessity of permanent anticoagulation due to artificial heart valve or for an atrial fibrillation with a recent cardioembolic stroke). In one patient the Tryton stent was successfully implanted into the bifurcation lesion on a Y-shaped vein graft, which gave rise to an interesting case study [12]. Duration of dual antiplatelet therapy after the Tryton stent implantation is mostly influenced by the type of the second stent implanted into the main vessel, with respect to the preferred use of DES dual antiplatelet therapy administered for 6–12 months. We used multi-slice CT coronary angiography to demonstrate the long-term patency of the implanted stents. Usage of CT coronarography in the demonstration of in-stent restenoses was assessed by Sun in his meta-analysis. The sensitivity and specificity of the 64-slice CT angiography in the detection of in-stent restenoses were 90% and 91%, respectively. The mean value of assessable stents was 89– 91%. Significantly higher diagnostic success was achieved during the evaluation of stents with the diameter greater than 3 mm (in comparison with stents under 2.75 or 2.5 mm) [13]. Our own data from another study also show that MS-CT coronarography is able to detect coronary in-stent restenosis with sufficient reliability (with sensitivity 80% and specificity 97.1%; 94.1% positive and 89.2% negative predictive values) [14]. A major obstacle of the stent lumen visualization is artifacts caused by the dense stent material. Although imaging of two overlapping stents by MS-CT coronarography is difficult, we achieved satisfactory visualization in 97.43% of bifurcation stents.
Conclusion The use of a dedicated bifurcation Tryton Side Branch Stent for PCI of the bifurcation lesions is technically feasible with satisfactory long-term results. This type of stent is beneficial
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especially in the treatment of bifurcation lesions with involvement of a large SB, which exceeds 5 mm from the carina that usually primarily require the implantation of two stents [8,9]. MS-CT coronarography is a reliable method of stent imaging event if two overlapping stents are to be visualized.
Conflict of interest The authors hereby declare that there is no conflict of interest concerning the work published in their study.
Funding body This article was co-supported by the project of the European Social Fund and the State Budget of the Czech Republic, registration number CZ.1.07/2.3.00/20.0040.
Ethical statement The authors hereby declare that the principles of publication ethics were followed during our manuscript preparation.
Informed consent The authors hereby declare that the patients gave the informed consent for the publication of their findings and results.
references
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