Summary
Background
Thrombus aspiration (TA) has been associated with high rates of thrombotic material retrieval, which results in improved myocardial reperfusion. In addition, a recent study has shown that systematic TA for treatment of ST-segment elevation myocardial infarction (STEMI) related to de novo lesions improves patient outcomes.
Aims
Evaluation of a single-centre experience of TA before percutaneous coronary intervention (PCI) for stent thrombosis (ST) treatment.
Methods
Between 2004 and 2006, we indexed 24 patients presenting with definite ST. All patients underwent TA (Export Medtronic ® 6F catheter) followed by PCI for ST treatment. Baseline clinical and angiographic characteristics, and complications related to the TA device were indexed.
Results
The median time of ST occurrence was 7 days. All patients except one presented with STEMI. Bare-metal and drug-eluting ST represented 70.8% and 29.2% of cases, respectively. Mean stent length was 18.8 ± 5.6 mm; mean stent diameter was 2.8 ± 0.4 mm; mean number of implanted stents was 1.58 ± 0.7. There was no failure to cross the catheter and no TA device-related complications were reported. The numbers of patients with initial thrombolysis in myocardial infarction (TIMI) flow grades 0, 1 and 2 were 15 (62.5%), 3 (12.5%) and 6 (25.0%), respectively. No patient had TIMI flow grade 3 before TA. After TA, 16 (66.7%) patients had TIMI flow grade 3; final procedural success was obtained in 23 (95.8%) patients. The 1-year death rate was 12.5%.
Conclusions
In our experience, TA before PCI for ST treatment shows promising results, providing high rates of immediate reperfusion and final angiographic success, and low death rates, compared with the literature.
Résumé
Rationnel
La technique de thrombo-aspiration (TA) permet d’aspirer du matériel thrombotique au niveau de l’artère coronaire résultant ainsi en une amélioration de la reperfusion myocardique. Par ailleurs, une étude récente a montré que l’utilisation systématique de cette technique pour le traitement des infarctus avec sus-décalage du segment ST améliorait le devenir des patients.
Objectifs
Rapporter l’expérience monocentrique de l’utilisation de la technique de TA avant angioplastie coronaire percutanée (ACP) dans le traitement des thromboses de stent.
Méthodes
Entre 2004 et 2006, nous avons répertorié 24 patients se présentant pour une thrombose de stent documentée par angiographie. Tous ces patients ont eu une TA (cathéter Medtronic Export ® 6F) suivi d’une ACP pour le traitement de cette thrombose de stent. Les caractéristiques cliniques et angiographiques ont été collectées ainsi que les complications liées à l’utilisation du système de TA.
Résultats
Le délai médian de survenue de la thrombose de stent était de sept jours. Tous les patients sauf un se sont présentés avec un infarctus avec sus-décalage du segment ST. La thrombose de stent était celle d’un stent nu dans 70,8 % des cas et d’un stent actif dans 29,2 % des cas. La longueur moyenne du stent était de 18,8 ± 5,6 mm et le diamètre moyen de 2,8 ± 0,4 mm. Le nombre moyen de stents implantés était de 1,58 ± 0,7. Il n’y a eu aucun échec de franchissement du système de TA et aucune complication liée au système n’a été rapportée. Avant TA, le nombre de patients avec un flux TIMI 0, 1 et 2 était de 15 (62,5 %), 3 (12,5 %) et 6 (25 %), respectivement. Aucun patient n’avait un flux TIMI 3 dans l’artère coupable. Après TA, le nombre de patients en flux TIMI 3 était de 16 (66,7 %) et un succès angiographique final a été obtenu chez 23 patients (95,8 %). Le taux de décès à un an après traitement était de 12,5 %.
Conclusion
Dans notre expérience, l’utilisation d’un système de TA avant ACP pour le traitement de la thrombose de stent semble prometteuse et a permis d’obtenir une restauration immédiate d’un flux TIMI 3 dans deux tiers des cas, des taux élevés de succès angiographique final et des taux de décès relativement bas en comparaison des données de la littérature.
Introduction
TA in patients undergoing primary PCI for the treatment of STEMI related to de novo lesions has been shown to be feasible, safe and associated with improved myocardial reperfusion and outcomes . Indeed, in the thrombus aspiration during percutaneous coronary intervention in acute myocardial infarction (TAPAS) trial , TA before stenting resulted in lower cardiac mortality and lower incidence of the composite endpoint of cardiac death or non-fatal reinfarction at 1 year.
Stent thrombosis is a rare event but is usually associated with poor outcomes . In addition, large thrombus burden in this context is the rule rather than the exception and the benefit of systematic TA in patients presenting with stent thrombosis is still poorly described. The present study reports a single-centre experience of systematic TA for the treatment of patients undergoing primary PCI for stent thrombosis.
Methods
Population and study design
Between August 2004 and December 2006, we indexed all patients presenting with definite stent thrombosis (according to the Academic Research Consortium definition) and treated by primary PCI in our centre. All patients included in this study underwent TA before PCI for stent thrombosis treatment. Patients with previous thrombolysis and patients treated by emergent coronary artery bypass surgery were excluded.
PCI procedures for stent thrombosis treatment
The device used for TA was the Export Medtronic ® 6F catheter. Then PCI, with or without coronary stent implantation, was performed in accordance with the standard technique usually used in our catheterization laboratory . All patients were pretreated with an intravenous bolus of aspirin 500 mg and an intravenous bolus of heparin 50 IU/kg; they also received a 300–600 mg loading dose of clopidogrel. The use of glycoprotein IIb/IIIa inhibitors and new stent implantation were at the discretion of the physicians and were driven by clinical and angiographic outcomes. Post-procedural treatment consisted of a combination of unfractionated heparin (12 IU/kg/h) or enoxaparin (0.1 mg/kg twice a day) in all patients for at least 72 h and dual antiplatelet therapy with aspirin 75 mg and clopidogrel 75 mg once daily for at least 1 year.
Film review
All coronary angiograms were reviewed by two cardiologists (A.S. and R.B.). The culprit lesion of stent thrombosis, initial TIMI flow grade, TIMI flow grade just after TA and final TIMI flow grade were analysed.
Follow-up
Clinical follow-up at 1 year was conducted by phone contact or office visits. In cases of new hospitalization, data were obtained by a systematic review of the discharge letter. During the 1-year follow-up period, the composite endpoint, which included death, recurrent myocardial infarction and recurrent stent thrombosis, was indexed systematically.
Definitions
Final procedural success was defined as normal TIMI flow grade 3 with a residual stenosis <30%. According to the Academic Research Consortium definition, definite stent thrombosis was defined as an angiographic confirmation of stent thrombosis (the presence of a thrombus that originates in the stent or in the segment 5 mm proximal or distal to the stent) associated with the presence of at least one of the following criteria within a 48-h time window:
- •
acute onset of ischaemic symptoms at rest;
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new ischaemic electrocardiogram changes that suggest acute ischaemia;
- •
typical rise and fall in cardiac biomarkers .
In patients where recurrent myocardial infarction was suspected from clinical signs or symptoms after the initial infarction, an immediate measurement of troponin and a second sample 6 h later were obtained; recurrent myocardial infarction was diagnosed if there was an increase in the value in the second sample of ≥20% .
Statistical analysis
Continuous variables are expressed as mean ± standard deviation, except for the delays, which are expressed as median [25th–75th percentile]. Categorical variables are expressed as absolute number and percentage.
Results
Population
During the study period, 31 patients presented with definite stent thrombosis in our centre. Patients with prehospital thrombolysis ( n = 5) and patients treated by emergent coronary artery bypass surgery ( n = 2) were excluded. Finally, 24 patients presented with definite stent thrombosis and underwent TA followed by PCI during the target period, and were considered for the present study. The median time of stent thrombosis occurrence was 7 days [3–54]. Early stent thrombosis was most frequent and occurred in 70.8% of the cases with a median time of 4.5 days.
Baseline characteristics of the patients are shown in Table 1 . The mean age of patients was 60.1 ± 12.3 years and 41.7% were diabetic. The mean stent length was 18.8 ± 5.6 mm and the mean stent diameter was 2.8 ± 0.4 mm. Twenty-three (95.8%) patients presented with STEMI; the last patient presented with non-STEMI. The left anterior descending artery was the main location of the stent thrombosis (58.3% of cases) followed by the right coronary artery (37.5% of cases).
| Variables | |
|---|---|
| Baseline clinical characteristics | |
| Age (years) | 60.1 ± 12.3 |
| Men | 21 (87.5) |
| Hypertension | 14 (58.3) |
| Tobacco smoking | 11 (45.8) |
| Diabetes mellitus | 10 (41.7) |
| Hypercholesterolaemia | 14 (58.3) |
| Body mass index (kg/m 2 ) | 26.3 ± 3.9 |
| Family history of cardiovascular disease | 6 (25) |
| Renal failure (clearance < 60 mL/kg) | 3 (12.5) |
| Left ventricular ejection fraction (%) | 41 ± 13.5 |
| Indication for initial percutaneous coronary intervention | |
| STEMI | 13 (54.2) |
| Non-STEMI | 5 (20.8) |
| Stable angina | 6 (25) |
| Clinical presentation at time of stent thrombosis | |
| STEMI | 23 (95.8) |
| Non-STEMI | 1 (4.2) |
| Timing of stent thrombosis | |
| Acute stent thrombosis | 5 (20.8) |
| Sub-acute stent thrombosis | 12 (50) |
| Late stent thrombosis | 3 (12.5) |
| Very late stent thrombosis | 4 (16.7) |
| Recent (<15 days) antiplatelet therapy cessation | 2 (8.3) |
| Initial angiographic characteristics | |
| Multivessel disease | 17 (70.8) |
| Target vessel | |
| LAD | 14 (58.3) |
| LCx | 1 (4.2) |
| RCA | 9 (37.5) |
| Reference vessel diameter (mm) | 2.8 ± 0.4 |
| Type of stent | |
| Bare-metal stent | 17 (70.8) |
| Sirolimus stent | 6 (25.0) |
| Paclitaxel stent | 1 (4.2) |
| Number of stents | 1.58 ± 0.7 |
| Total stent length (mm) | 18.8 ± 5.6 |
| Maximal balloon diameter (mm) | 2.8 ± 0.4 |
| Balloon/artery ratio | 1 ± 0.1 |
| Angiographic success | 24 (100) |
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