1. Stent Thrombosis Rates in Contemporary Clinical Practice: Insight from a Large Australian Multi-centre Registry
BP Yan*, TJ Kiernan, SJ Duffy, DJ Clark, R Warren, A Brennan, N Andrianopoulos, C Reid & AE Ajani
Background:
Recent reports suggest that drug-eluting stents (DES) may increase the risk of stent thrombosis (ST) relative to bare-metal stents (BMS). The aim of this study was to compare DES and BMS outcomes with a specific focus on ST.
Methods:
We analysed 30-day and 1-year outcomes of 2919 patients who underwent percutaneous coronary intervention with stent implantation from the Melbourne Interventional Group (MIG) registry. The Academic Research Consortium (ARC) definitions of ST were used: (i) “definite ST” (confirmed by angiography in acute coronary syndrome patients), (ii) “probable ST” (unexplained death <30 days or target-vessel myocardial infarction without angiographic confirmation) and (iii) “possible ST” (unexplained death >30 days). Multivariate analysis was performed to identify predictors of ST.
Results:
The incidence of ST (early or late) was comparable between BMS and DES (1.6 vs. 2.2%, p=0.66), and DES use was not predictive of ST. Independent predictors of ST included absence of clopidogrel therapy at 30-days (odds ratio (OR) 2.58, 95%CI , p<0.01), renal failure (OR 3.30, 95%CI , p<0.01), index procedure-presentation with an acute coronary syndrome (OR 2.59, 95%CI , p=0.02), diabetes mellitus (OR 2.25, 95%CI , p=0.01) and total stent length ≥20mm (OR %CI , p=0.04).
Conclusion:
Fig Month Clinical Outcomes
Table 1. Patient Characteristics
Fig 1. Kaplan Meier : Freedom from Stent Thrombosis
DES
N=1630
BMS
N=1289 P
Patients, %
55.8
44.2 -
Age, yrs ± SD
65.4 ± 11.9
64.4 ± 11.9
0.03
Male, %
73.0
73.2 NS
Diabetes Mellitus, %
29.6
14.0
<0.01
Hypertension, %
61.0
61.5
Hypercholesterolaemia, %
68.9
70.0
Current smoking, %
18.2
25.6
Previous MI, %
31.3
26.2
Renal Failure, %
4.9
4.6
Table 5. Independent Predictors of Any Stent Thrombosis
Table 2. Lesion Characteristics
Variable
Hazard Ratio
95% CI P
All (n=44)
Renal Failure
3.30
<0.01
Acute coronary syndrome
2.59
0.02
Absence of clopidogrel at 30 days
2.58
Diabetes
2.25
0.01
Total stent length > 20mm
1.85
0.05
Early (n=15)
9.62
Late (n=29)
5.25
Renal failure
5.07
DES
N=2127
BMS
N=1456 P
Target vessel
left main, %
1.1
0.7 NS
LAD, %
33.9
30.3
RCA, %
25.8
40.3
<0.01
Bypass grafts, %
3.3
2.1
Lesion type
Type B2/C, %
51.2
38.5
Total stent length >20mm, %
38.0
20.9
Stent diameter <2.5mm, %
39.4
19.0
Glycoprotein 2b/3a inhibitor, %
25.3
27.9
Table 4.
Absence of Clopidogrel Use
Follow-up
No ST
N=2875 ST
N=44 P
30 days, %
13.5
36.4
<0.01
12 months, %
47.1
65.9
Table 6. Independent Predictors of DES Thrombosis
Variable
Hazard Ratio
95% CI P
All (n=22)
Absence of clopidogrel at 30 days
3.94
<0.01
Renal Failure
3.91
Diabetes
2.90
0.01
Early (n=11)
16.39
Late (n=11)
Acute coronary syndrome
10.01
0.03
9.56
Ostial Lesion
5.58
0.02
4.89
At 12 months, DES were not associated with an increased risk of stent thrombosis compared with BMS in this large Australian registry that selectively used DES for patients at high-risk of restenosis
Absence of clopidogrel therapy, renal failure & diabetes were independent predictors of stent thrombosis
BMS use in less complex lesions resulted in comparable clinical outcomes to DES in selected high-risk patients
Issue of DES thrombosis is not resolved as concern of stent thrombosis continues beyond 12 months
Table 3. Incidence of Stent Thrombosis
Overall
DES
BMS P
OR (95%CI)
Early <30 days
15 (0.5%)
11 (0.7%)
4 (0.3%) NS
2.2 ( )
Definite 8 6 2 -
Probable 7 5
Late >30 days
24 (1.0%)
15 (0.9%)
14 (1.1%)
0.9 ( ) 10 3 1
Possible 16
Total
44 (1.5%)
26 (1.6%)
18 (1.4%)
1.2 ( )