Percutaneous coronary intervention (PCI) in unprotected left main coronary artery disease (ULMCAD) has become a safer and more efficient treatment method. Although coronary artery bypass grafting (CABG) was the standard treatment for complex left main lesions, an increasing number of patients with ULMCAD are treated by PCI [1,2,3]. Here we can include both patients with low or intermediate syntax scores and more and more patients with high syntax scores who have contraindications for surgery due to comorbidities or due to local surgical expertise [2, 4,5,6].
Developments in stents have made it possible to address complex cases of left main stenosis [7, 8]. The introduction of the self-apposing stent (Stentys) made it possible to treat left main lesions in which there were aneurysms or significant dilatations of the coronary arteries – large discrepancies between the diameter of the main proximal vessel and the distal proximal vessel – due to the special properties of this stent. The stent Stentys (Stentys, France) is a self-apposing device constructed of nickel and titanium alloy characterized by the ability to push externally, increasing its dimensions only upon reaching the vessel wall, or a predictable maximal diameter dependent on the size of the device used [9].
These properties of the Stentys stent have removed, at least in theory, several problems of left main angioplasty:
the difference in diameter between left main and left anterior descending artery (LAD), making the use of proximal optimization technique (POT) unnecessary opening the stent struts to the side branch the use of kissing balloon is not mandatory due to the ability of the stent to conform to the anatomy of the left main bifurcation [9].
Many of these assumptions made at the introduction of the stent have been tested, some being refuted, and others confirmed [10, 11]. Leaving aside the above, the left main angioplasty technique must remain standardized according to the recommendations in use.
The aim of current study was to compare the four-year outcomes of patients with ULMCAD treated by PCI with a balloon expandable stent or a self-apposing stent (Stentys stent), including both elective patients and patients presenting with acute coronary syndrome (ACS).
All patients with ULMCAD treated by PCI between January 2014 and December 2018 were selected from the electronic hospital records at the Prof. Dr. C.C. Iliescu Institute for Cardiovascular Diseases, Bucharest, Romania. Patients with a history of CABG and occluded grafts and patients presenting with ACS were included. Only patients with complete data were included in the study. This resulted in a total of 146 patients for which demographic, clinical, angiographic, procedural, post-procedural and outcome data were extracted from the hospital electronic records. Life status was verified using the National Insurance Agency Platform in June 2019 to identify possible out-of-hospital deaths. Data analysis was performed with the approval of the institutional ethics committees of the hospital involved.
Major adverse cardiac events (MACEs) were defined as the occurrence of death, myocardial infarction (MI) or target lesion revascularizations (TLRs). ACS was defined as either unstable angina, non-ST segment elevation MI (NSTEMI) or ST segment elevation MI (STEMI). TLR was defined as repeated PCI for restenosis of the entire segment involving the implanted stent and the 5-mm distal and proximal borders adjacent to the stent. Angiographic success was defined as residual stenosis of <30% by visual estimation in the presence of thrombosis in myocardial infarction (TIMI), flow grade 3. Complete revascularization was defined as any attempt to revascularize all diseased segments (≥2.5 mm in diameter).
Frequencies are given as numbers and percentages, continuous values as median (inter-quartile range or minimum-maximum values). Population characteristics were compared using the Mann-Whitney U test, Kruskall Wallis test and Fisher's exact test. Patients were divided into two main groups based on the type of stent used during PCI: Group A used a balloon-expandable stent, while Group B used a self-apposing stent.
Early outcomes (mortality, stent thrombosis, need for intraaortic balloon pump (IABP), access site complications) are based on known status at 30 days and presented as percentages. Late outcomes are estimated using the Kaplan Meier method. Late outcomes of interest are: mortality, TLR and MACE.
Predictors of early outcomes were identified using univariable linear regression adjusted by acute coronary syndrome at the time of procedure. Multivariable analysis was not possible due to only 12 early events. Predictors of late outcomes (death, TLR) were identified using a combination of backward and forward stepwise multivariable Cox regression, including all variables with a univariable regression p value of less than 0.1 and less than <10% missing values. The statistically significant variables left in the final model were considered independent predictors. The Group A vs Group B variable was always kept in the model, as a variable of interest. Statistical analyses were done with STATA/SE 12.0 (StataCorp LP, College Station, TX).
A total of 146 patients undergoing left main PCI were included, age ranging from 33 to 86 years (median of 63 years). Group A consisted of n=84 (57.5%), Group B of the remaining n=62 (42.5%). Detailed demographic and baseline clinical characteristics by group are presented in Table 1. We found few significant differences among the two groups, namely more patients with peripheral artery disease in Group A (25% Group A vs 6.6% Group B, p=0.004).
Demographic and baseline clinical characteristics according to the type of the implanted stent in patients with unprotected left main coronary artery disease (ACS – acute coronary syndrome; NSTEMI – non-ST segment elevation myocardial infarction; STEMI – ST segment elevation myocardial infarction; PCI – percutaneous coronary intervention; TIA – transient ischemic attack; COPD - chronic obstructive pulmonary disease; PAD – peripheral artery disease; LBBB – left bundle branch block; RBBB – right bundle branch block; LVEF – left ventricular ejection fraction; HB – hemoglobin)
63 (56–72) | 62 (52–70) | 63 (55–71) | 0.2 | |
58 (69.1) | 44 (71) | 102 (69.9) | 0.8 | |
71 (84.5) | 51 (83.6) | 0.5 | ||
73 (86.9) | 53 (86.9) | 126 (86.9) | 0.6 | |
25 (29.8) | 17 (27.9) | 42 (29) | 0.8 | |
21 (25) | 17 (27.4) | 38 (26) | 0.8 | |
25 (30.1) | 18 (29.5) | 43 (29.9) | 0.8 | |
16 (19.3) | 10 (16.4) | 26 (18.1) | 0.8 | |
32 (38.1) | 26 (42.6) | 58 (40) | 0.6 | |
3 (9.4) | 3 (11.5) | 6 (10.3) | ||
11 (34.4) | 5 (19.2) | 16 (27.6) | ||
18 (56.2) | 18 (69.3) | 36 (62.1) | 0.4 | |
20 (23.8) | 14 (22.6) | 34 (23.3) | 0.5 | |
11 (13.1) | 8 (13.1) | 19 (13.1) | 0.6 | |
10 (11.9) | 5 (8.1) | 15 (10.3) | 0.6 | |
2 (2.4) | 3 (4.9) | 5 (3.4) | 0.6 | |
1 (1.2) | 1 (1.6) | 2 (1.4) | 0.7 | |
21 (25) | 4 (6.6) | 25 (17.2) | 0.004 | |
9 (10.7) | 0 (0) | 9 (6.2) | 0.01 | |
40 (47.6) | 30 (48.4) | 70 (47.9) | ||
19 (22.6) | 11 (17.7) | 30 (20.5) | ||
9 (10.7) | 7 (11.3) | 16 (11) | ||
10 (11.9) | 8 (12.9) | 18 (12.3) | ||
6 (7.2) | 6 (9.7) | 12 (8.2) | 0.9 | |
7 (8.6) | 5 (8.1) | 12 (8.4) | 0.6 | |
6 (7.4) | 3 (4.8) | 9 (6.3) | 0.4 | |
7 (8.6) | 4 (6.4) | 11 (7.7) | 0.4 | |
0 (0) | 2 (3.2) | 2 (1.4) | 0.2 | |
50 (35–55) | 50 (38–60) | 50 (35–57.5) | 0.6 | |
42 (50.6) | 32 (52.5) | 74 (51.4) | ||
16 (19.3) | 13 (21.3) | 29 (20.1) | ||
15 (18.1) | 10 (16.4) | 25 (17.4) | ||
10 (12) | 6 (9.8) | 16 (11.1) | 0.9 | |
71 (92.2) | 49 (84.4) | 120 (88.9) | 0.2 | |
58 (71.6) | 38 (62.3) | 96 (67.6) | 0.3 | |
5 (6.1) | 4 (6.6) | 9 (6.3) | 0.6 | |
2 (2.4) | 0 (0) | 2 (1.4) | 0.5 | |
31 (41.3) | 14 (24.6) | 45 (30.1) | 0.06 | |
4 (4.8) | 3 (4.9) | 7 (4.9) | 0.6 | |
12 (14.5) | 2 (3.3) | 14 (9.8) | ||
51 (61.4) | 45 (75) | 96 (67.1) | ||
12 (14.5) | 10 (16.7) | 22 (15.4) | ||
8 (9.6) | 3 (5) | 11 (7.7) | 0.09 | |
61 (73.5) | 40 (66.7) | 101 (70.6) | ||
15 (18.1) | 20 (33.3) | 35 (24.5) | ||
7 (8.4) | 0 (0) | 7 (4.9) | ||
0 (0) | 0 (0) | 0 (0) | 0.01 | |
32 (30–34) | 34 (31–37) | 32 (30–35) | 0.02 | |
3 (3.6) | 0 (0) | 6 (4.2) | 0.3 | |
50 (60.2) | 40 (65.6) | 90 (62.5) | 0.6 | |
15 (20) | 4 (7) | 19 (14.4) | 0.04 | |
13.4 (12.2–14.4) | 13.9 (12.5–15) | 13.5 (12.3–14.7) | 0.1 | |
25 (18–63) | 22 (16–37) | 22 (17–50) | 0.2 | |
0.24 (0.03–1.3) | 1 (0.07–4.8) | 0.3 (0.03–2.9) | 0.2 | |
0.9 (0.8–1.2) | 0.9 (0.8–1.2) | 0.9 (0.8–1.2) | 0.9 | |
80 (62–97) | 80 (65–95) | 80 (64–96) | 0.9 |
SYNTAX, SYNTAX II (PCI and CABG, with respective predicted mortality) and EuroSCORE II scores for the two groups are detailed in Table 2. SYNTAX scores are higher in patients treated with balloon-expandable stents compared to patients treated with self-apposing stents.
SYNTAX, SYNTAX II (for PCI and CABG, with respective predicted mortality) and EuroSCORE II scores of patients with unprotected left main coronary artery disease according to the stent strategy
SYNTAX | 23.5 (16.5–30.5) | 17.5 (11–25.5) | 21 (13–29) | 0.004 |
SYNTAX-2 PCI | 34.1 (25.6–45.4) | 28.9 (22.1–40.7) | 32.2 (23.6–43.6) | 0.04 |
Estimated PCI mortality | 9.8 (4.9–22.7) | 6.2 (3.6–15.9) | 8.3 (4.1–19.9) | 0.03 |
SYNTAX-2 CABG | 31.5 (23.3–40.9) | 25.3 (16.4–33.6) | 28.9 (19.4–38) | 0.01 |
Estimated CABG mortality | 7.7 (3.9–16.2) | 4.6 (2.2–10.3) | 6.2 (2.9–13.6) | 0.01 |
EUROSCORE II | 1.6 (1–3.3) | 1.1 (0.8–2.5) | 1.3 (0.9–2.8) | 0.1 |
Table 3 shows the main angiographic findings by type of stent used. Self-apposing stents were implanted more often in patients with distal left main lesions compared to balloon-expandable stents (69% in balloon-expandable group vs 87.1% in self-apposing group, p=0.009). Self-apposing stents were used more often in Medina 0/1/0 lesions compared to balloon-expandable stents (15.1% in balloon-expandable group vs 41.9% in self-apposing group, p=0.01).
Angiographic findings of patients with unprotected left main coronary artery disease according to the type of implanted stent (LM – left main; LAD – left anterior descending artery; LCX – left circumflex artery; RCA – right coronary artery)
Radial | 16 (19.1) | 18 (29) | 34 (23.3) | 0.2 |
Femoral | 68 (80.9) | 44 (71) | 112 (76.6) | 0.2 |
Left main lesion localization | ||||
Ostial | 10 (11.9) | 0 (0) | 10 (6.9) | |
Middle segment | 1 (1.2) | 0 (0) | 1 (0.7) | |
Distal | 58 (69) | 54 (87.1) | 112 (76.7) | |
Ostial and distal | 1 (1.2) | 3 (4.8) | 4 (2.7) | |
Whole length | 14 (16.7) | 5 (8.1) | 19 (13) | 0.009 |
Bifurcation | 63 (75) | 52 (83.9) | 115 (78.8) | 0.2 |
Trifurcation | 21 (25) | 10 (16.1) | 31 (21.2) | 0.2 |
None | 24 (28.6) | 25 (40.3) | 49 (33.6) | |
One vessel | 27 (32.1) | 17 (27.4) | 44 (30.1) | |
Two vessels | 23 (27.4) | 16 (25.8) | 39 (26.7) | |
Three vessels | 10 (11.9) | 4 (6.5) | 14 (9.6) | 0.4 |
Chronic total occlusion | 17 (20.2) | 14 (22.6) | 31 (21.2) | 0.8 |
LAD ostium involved | 45 (53.6) | 50 (80.6) | 95 (65.1) | 0.001 |
LCX ostium involved | 36 (42.9) | 24 (38.7) | 60 (41.1) | 0.7 |
LAD non-ostial lesion | 41 (48.8) | 23 (37.1) | 64 (43.8) | 0.2 |
LCX non-ostial lesion | 27 (312.1) | 13 (21) | 40 (27.4) | 0.2 |
RCA lesion | 28 (33.3) | 20(32.3) | 48 (32.9) | 0.5 |
Diffuse lesion | 49 (5.3) | 27 (43.5) | 76 (52.1) | 0.09 |
Eccentric lesion | 64 (76.2) | 43 (69.4) | 107 (73.3) | 0.4 |
Calcified lesion | 29 (34.5) | 14 (22.6) | 43 (29.4) | 0.1 |
Ulcerated lesion | 21 (25) | 15 (24.2) | 26 (25.7) | 0.5 |
Carina involved | 4 (4.8) | 5 (8.1) | 9 (6.2) | 0.5 |
1/1/1 | 22 (30.1) | 12 (19.4) | 34 (25.2) | |
1/0/0 | 17 (23.3) | 6 (9.7) | 23 (17.1) | |
1/1/0 | 10 (13.7) | 6 (9.7) | 16 (11.9) | |
1/0/1 | 6 (8.2) | 3 (4.8) | 6 (6.7) | |
0/1/0 | 11 (15.1) | 26 (41.9) | 37 (27.4) | |
0/1/1 | 4 (5.5) | 6 (9.8) | 10 (7.4) | |
0/0/1 | 3 (4.1) | 3 (4.8) | 6 (4.4) | 0.01 |
True bifurcation (1/1/1, 0/1/1) | 26 (35.6) | 18 (29) | 44 (32.6) | 0.5 |
Left main take-off angle >700 | 22 (32.8) | 22 (37.9) | 44 (35.2) | 0.6 |
>90 degrees | 5 (8.1) | 7 (12.1) | 12 (10) | |
70–90 | 24 (38.7) | 24 (41.4) | 48 (40) | |
45–69 | 11 (17.7) | 10 (17.2) | 21 (17.5) | |
<45 | 22 (35.5) | 17 (29.3) | 39 (32.5) | 0.8 |
LM stenosis, % (median, IQR) | 67 (45–89) | 30 (11–57) | 55 (20–80) | <0.001 |
LAD stenosis, % (median, IQR) | 83 (58–90) | 86 (71–93) | 85 (66–92) | 0.006 |
LCX stenosis, % (median, IQR) | 71 (43–84) | 63 (18–86) | 70 (30–86) | 0.4 |
As expected, true bifurcation lesions (Medina 1/1/1) were more frequent in Group A (30.1% in Group A vs 19.4 in Group B, p=0.01).
Six patients (4.1%) were on mechanical support system with IABP prior to the PCI procedure [12, 13]. Radial access was used more often with self-apposing stents (19.4% in self-apposing Group vs 3.6% in balloon-expandable Group, p=0.004).
Minicrush technique was used more often with balloon-expandable stents (16% in self-apposing Group vs 43.7% in balloon-expandable Group, p=0.03) and Cullotte technique with self-apposing stents (40% in self-apposing Group vs 9.4% in balloon-expandable Group, p=0.03).
POT was used more often with balloon-expandable stents (45.2% in self-apposing Group vs 81.4% in balloon-expandable Group, p<0.001). The same observations were made for KBPD (30.6% in self-apposing Group vs 62.7% in balloon-expandable Group, p<0.001) (table 4).
Procedural characteristics according to the type of implanted in patients with unprotected left main coronary artery disease (PCI – percutaneous coronary intervention; IABP – intra-aortic balloon pump; LAD – left anterior descending artery; LCX – left circumflex artery; POT – proximal optimization technique; KBPD – kissing balloon post dilatation; TKBPD – triple kissing balloon post dilatation; MV – main vessel; SB – side branch; iFR - instantaneous wave-free ratio; IVUS – intravascular ultrasound)
Time from coronary angiogram to PCI, days (median, IQR) | 2 (0–22.5) | 2.5 (0–20) | 2 (0–20) | 0.8 |
Femoral | 81 (96.4) | 50 (80.6) | 131 (89.7) | 0.004 |
Radial | 3 (3.6) | 12 (19.4) | 15 (10.3) | 0.004 |
Pre-PCI IABP | 5 (5.9) | 1 (1.6) | 6 (4.1) | 0.2 |
6F | 47 (55.9) | 31 (50) | 78 (53.4) | |
7F | 37 (44.1) | 29 (46.8) | 66 (45.2) | |
8F | 0 (0) | 2 (3.2) | 2 (1.4) | 0.2 |
Rotational atherectomy | 2 (2.4) | 1 (1.6) | 3 (2.1) | 0.6 |
35 (41.7) | 25 (40.3) | 0.5 | ||
Provisional stenting | 1 (3.1) | 0 (0) | 1 (1.7) | |
TAP | 10 (31.2) | 10 (40) | 20 (35.1) | |
Minicrush | 14 (43.7) | 4 (16) | 18 (31.6) | |
DK-Crush | 3 (9.4) | 0 (0) | 3 (5.3) | |
Cullotte | 3 (9.4) | 10 (40) | 13 (22.8) | |
V-stenting | 1 (3.1) | 1 (4) | 2 (3.5) | 0.03 |
MV predilatation | 62 (78.5) | 49 (79) | 111 (78.7) | 0.5 |
SB predilatation* | 29 (40.9) | 19 (30.7) | 48 (36.1) | 0.4 |
Predilatation at nominal pressure** | 21 (30.4) | 24 (46.1) | 40 (36) | 0.3 |
Dissection | 19 (26.4) | 9 (17.3) | 26 (23.4) | 0.2 |
POT* | 57 (81.4) | 28 (45.2) | 87 (64.4) | <0.001 |
POT after first stent*** | 46 (78) | 22 (78.6) | 68 (50.4) | 0.6 |
POT after KBPD*** | 32 (54.2) | 6 (21.4) | 38 (28.2) | 0.005 |
POT balloon diameter*, mm (median, IQR) | 4 (4–4.5) | 4 (4–4.5) | 4 (4–4.5) | 0.9 |
KBPD* | 42 (62.7) | 19 (30.6) | 62 (45.9) | <0.001 |
TKBPD* | 5 (7.2) | 0 (0) | 5 (3.7) | 0.03 |
MV stent diameter | ||||
3 | 14 (16.7) | 18 (29.3) | 32 (21.9) | |
3.5 | 53 (63.1) | 44 (71) | 97 (66.4) | |
4 | 17 (20.2) | 0 (0) | 17 (11.6) | <0.001 |
MV stent length, mm (median, IQR) | 24 (16–29) | 22 (18–25) | 22 (18–28) | |
SB stent diameter, mm (median, IQR) | 3 (3–3.5) | 3.5 (3–3.5) | N/A | 0.5 |
SB stent length, mm (median, IQR) | 19 (13–23) | 22 (18–27) | N/A | 0.06 |
Under expansion of >30% | 6 (7.1) | 8 (12.9) | 14 (9.6) | 0.3 |
IFR used pre-PCI | 2 (2.4) | 4 (6.5) | 6 (4.1) | 0.4 |
IFR used post-PCI | 0 (0) | 4 (6.5) | 4 (2.8) | 0.03 |
IVUS used pre-PCI | 2 (2.4) | 0 (0) | 2 (1.4) | 0.5 |
IVUS used post-PCI | 12 (14.3) | 14 (22.6) | 26 (17.8) | 0.3 |
Procedural success with TIMI 3 flow was achieved in similar proportions in both groups (Table 5). Instantaneous wave-free ratio (iFR) was performed before the PCI in 6 cases (4.4%) and after in 4 cases (3%). In 2 cases (1.5%) intravascular ultrasound (IVUS) was used before the procedure, while in 26 (19.3%) it was used after the procedure [14].
Procedural outcomes and post-procedural complications according to the type of implanted stent in patients with unprotected left main coronary artery disease (LM – left main; SB – side branch; TIA – transient ischemic attack; PCI – percutaneous coronary intervention; CIN – contrast induced nephropathy)
Unaffected LM ostium covered by implanted stent | 12 (14.3) | 6 (9.7) | 18 (13.3) | 0.4 |
LM lesion covered | 84 (100) | 60 (96.8) | 133 (98.5) | 0.2 |
None | 50 (67.5) | 36 (58.1) | 83 (62.4) | |
<50% | 17 (23) | 21 (33.9) | 38 (28.6) | |
>50% | 7 (9.5) | 5 (8) | 12 (9) | 0.4 |
Procedural success | 81 (96.4) | 57 (91.9) | 138 (94.5) | 0.3 |
Complete revascularization | 63 (75) | 46 (74) | 109 (74.7) | 0.5 |
1 | 1 (1.2) | 3 (4.8) | 4 (2.7) | |
2 | 3 (3.6) | 1 (1.6) | 4 (2.7) | |
3 | 80 (95.2) | 58 (93.6) | 138 (94.5) | 0.4 |
Hematoma | 3 (3.6) | 3 (4.8) | 6 (4.1) | 0.7 |
Stroke/TIA | 1 (1.2) | 0 (0) | 1 (0.7) | 0.6 |
MI | 1 (1.2) | 3 (4.8) | 4 (2.7) | 0.2 |
Afib | 1 (1.2) | 1 (1.6) | 2 (1.5) | 0.8 |
Need for external electric shock | 1 (1.2) | 3 (4.8) | 4 (2.7) | 0.3 |
Bradi-arrhythmia | 3 (3.6) | 7 (11.3) | 10 (6.9) | 0.1 |
Death during PCI | 1 (1.2) | 2 (3.2) | 3 (2) | 0.6 |
CIN* | 9 (16.4) | 5 (13.2) | 14 (15.1) | 0.8 |
Technical outcomes and post-procedural complications by strategy group are summarized in Table 5. There were no differences between the two groups in term of peri-procedural complications.
There was an 8.2% early mortality (30 days mortality) (n=12), with a 2% peri-procedural mortality (n=3). Most deaths occurred in patients presenting with ACS (n=11) and mostly in patients complicated with cardiogenic shock (n=8). As such, early mortality in non-ACS patients was 1.4% with no peri-procedural deaths [14].
30-days mortality was 11.29% in patients treated with self-apposing stents and 5.95% in patients treated with balloon-expandable stents, but without statistically significant difference.
Mortality, TLR and MACE at 4 years were 21.9%, 14% and 32.5% overall, 9.6%, 15% and 24.1% in non-ACS patients and 33.3%, 12.8% and 40.1% respectively in ACS-patients, respectively. Unadjusted comparisons of mortality, TLR and MACE at 4 years between Group A and Group B are shown in Figure 1. Mortality rate and MACE rates at 4-year follow up were higher in Group B compared to Group A but have not reached statistical significance in univariable or multivariable analysis.
Unadjusted comparisons of mortality, TLR and MACE at 4 years according to the type of the stent in patients with unprotected left main coronary artery disease. Curves represent Kaplan-Meier failure function.
Implantation of a self-apposing stent has an independent predictor for TLR in multivariable analysis (HR 0.06, CI − 1.11–11.7, =0.03).
The study included an unselected population of patients with ULMCAD treated by PCI. Thus, patients who presented with acute coronary syndrome were not excluded from the study, considering in the analysis also severe patients with cardiogenic shock. The aim of this study was to highlight the results obtained after left main angioplasty performed with different stent platforms in an interventional cardiology center with a large volume of cases, both in elective patients and in priority or urgent patients. The study included 146 patients with ULMCAD PCI, of whom 52.06% had acute coronary syndrome. The study population was divided into 2 groups depending on the type of stent used for left main PCI: group A – balloon-expandable stents and group B - self-apposing stents. There is little data on the comparison of the two types of stents in current practice in both elective and acute coronary patients.
A first significant difference is that patients treated with self-apposing stents had lower risk scores, both anatomical and combined, than patients treated with balloon-expandable stents. Thus, we could say that self-apposing stents are implanted in less complex cases. This is since the implantation of a self-apposing stents requires the most appropriate predilation of the lesion and the passage of the stent through the lesion is more difficult due to the higher profile than the balloon-expandable stents [9, 10].
There is a preference for a particular type of stent depending on the location of the lesion in the left main. Patients with ostial and mid-segment lesions were not treated using a self-apposing stent. Self-apposing stents are considered to have a lower radial force than balloon-expandable stents. This makes their use in aortoostial lesions lower, due to the high resistance of this area and the greater tendency to “recoil” of the implanted stent. The self-apposing stent was preferred in distal left main lesions, especially in patients with LAD ostial lesion, Medina 0/1/0 [9].
POT and KBPD were performed much more frequently in the case of balloon-expandable stents. This is due to the properties of the self-apposing stents to self-appose to the vessel wall (hence the theoretical lack of the need for proximal optimization) and minimal deformation when the struts to the side branch are opened (hence the theoretical lack of the need for kissing balloon) [10, 11].
There was no difference in mortality rate and 4-year MACE rate between the two groups. However, the rate of revascularization of the target lesion was significantly higher when a self-apposing stent was used. Although there is no evidence from studies of exvivo models, self-apposing stents tend to narrow the ostium of the secondary vessel over time, precisely because of their properties of continuing to expand over time.
This study was a nonrandomized study in which operator bias may have influenced the final conclusion. Although it might have offered more data on restenosis, routine angiographic reevaluation is no longer recommended and was not performed. The small number of early events prevented multivariable analyses, so the results are subject to confounding. The use of various types of stents introduces a degree of heterogeneity.
Although there are differences in the technique of angioplasty between patients treated with self-apposing stents compared to those treated with balloon-expandable stents, the mortality and MACE rates at 4 years did not differ between the two types of stents. However, TLR was significantly higher in patients with left main lesion treated by PCI with self-apposing stents.