Summary
Background
Drug-eluting stents (DES) are more effective than bare-metal stents (BMS) in small coronary vessel disease. Whether this is true in elderly patients, it is unclear, as frailty and a high rate of comorbidities could increase the rate of DES-related complications.
Aims
To assess procedural and long-term clinical outcomes of elderly patients with small vessel disease treated with DES or BMS.
Methods
Consecutive elderly patients (≥ 75 years old) treated with stenting of native small coronary arteries (reference vessel diameter and implanted stent < 3 mm) were recruited during 2004–2008. Procedural and long-term clinical outcomes were compared between patients treated with BMS and DES. Propensity score-adjusted logistic regression analysis was performed to account for potential selection bias.
Results
Among 293 patients (175 BMS, 118 DES), peri-procedural myocardial infarction (12 [7%] vs. 5 [4%]; P = 0.35) and blood transfusions (3 [2%] vs. 0; P = 0.08) were not significantly different between the BMS and DES groups. Clinical follow-up (96% of patients, median [interquartile range] follow-up 3.5 [2.4] years) showed significantly lower adjusted major adverse cardiac events (hazard ratio [HR] 0.42, 95% confidence interval [CI] 0.24–0.72; P = 0.002) and target vessel revascularization (TVR) (HR 0.33, 95% CI 0.14–0.76; P = 0.009) in the DES group. No significant differences were observed between the groups in terms of death, myocardial infarction, stent thrombosis or bleeding.
Conclusions
In this retrospective, non-randomized analysis of the treatment of small vessel disease in elderly patients, DES were as safe and more effective than BMS with a significant reduction in TVR.
Résumé
Contexte
Les stents actifs (SA) sont plus efficaces que les stents non-actifs (SNA) pour traiter les lésions des petits vaisseaux coronaires. Le bénéfice des SA chez les patients âgés sont plus discutés car il s’agit de patients plus fragiles, avec plus de comorbidités et donc plus exposés aux effets indésirables.
Objectif
Évaluer les procédures et le devenir à long-terme des patients âgés avec des lésions dans les petits vaisseaux traités par SA versus SNA.
Méthodes
Tous les patients âgés (≥ 75 ans) avec des lésions primitives dans les petits vaisseaux (diamètre de référence ou stent < 3 mm) traités par angioplastie avec pose de stent ont été recrutés entre 2004 et 2008. Les procédures et le devenir à long-terme ont été comparés selon le type de stent implanté. Une régression logistique et un score de propensité ont été utilisés pour s’affranchir d’éventuels biais.
Résultats
Deux cent quatre-vingt-treize patients ont été inclus (175 SNA, 118 SA). Le nombre d’infarctus (12 [7 %] vs 5 [4 %] ; p = 0,35) et de transfusions (3 [2 %] vs 0 ; p = 0,08) en post-procédure n’étaient pas différents. Le suivi clinique (96 % des patients, suivi moyen [intervalle interquartile] 3,5 [2,4] ans) a montré moins d’événements cardiovasculaires majeurs (risque relatif [RR] 0,42, 95% intervalle de confiance [IC] 0,24 – 0,72 ; p = 0,002) et moins de revascularisation dans le vaisseau traité (RR 0,33, 95 % IC 0,14 – 0,76 ; p = 0,009) chez les patients avec SA. Aucune différence significative n’a été observée entre les groupes concernant les décès, les infarctus, les thromboses de stents et les saignements.
Conclusions
Les SA ne sont pas seulement plus sures, mais sont aussi plus efficaces que les SNA pour le traitement des lésions dans les petits vaisseaux chez les patients âgés. Le bénéfice clinique à long-terme était principalement lié à la réduction de la revascularisation dans les vaisseaux traités avec les SA.
Introduction
Elderly patients are increasingly being referred for percutaneous coronary intervention (PCI). Yet, due to their increased frailty and higher rate of comorbidities , they are commonly considered to be at high risk of PCI-related complications and therefore suboptimally treated compared with younger patients . Drug-eluting stents (DES), for example, are not implanted due to a hypothetical higher risk of device-related complications (i.e. stent thrombosis or bleeding in the case of premature withdrawal or prolonged dual antiplatelet therapy, respectively). Nevertheless, elderly patients are potentially those who could benefit the most from the use of DES considering the high prevalence of lesion characteristics that increase the restenosis risk, such as multivessel and small coronary artery disease .
We recently demonstrated, in an all-comer patient population, that DES of small vessel disease is associated with a significant reduction in target vessel revascularization (TVR) compared with bare-metal stenting . This beneficial effect of DES was persistent at long-term follow-up and did not increase the risk of myocardial infarction, stent thrombosis or bleeding. Of interest, a low TVR rate of 17% was noted with the latest generation thin-strut chrome-cobalt BMS. Therefore, their use could be of interest in patients at high risk of bleeding with prolonged dual antiplatelet therapy, such as elderly patients. However, few studies have assessed the efficacy of DES in small vessel disease in elderly patients.
The aim of this retrospective study was therefore to assess the long-term clinical outcome of elderly patients with small vessel disease treated with DES compared with the latest generation thin-strut chrome-cobalt bare-metal stent (BMS).
Methods
Patient population
From January 2004 to December 2008, we included consecutive elderly patients (≥ 75 years) treated with PCI and stent implantation of native small coronary vessels. Small vessel disease was defined as a reference vessel diameter < 3 mm (as assessed by quantitative coronary angiography) and/or size of the stent implanted < 3 mm. Patients were excluded if: (1) they were treated with PCI and stenting in another vessel > 3 mm; (2) PCI was performed without stent implantation; (3) PCI was performed on a bypass-graft; or (4) patients received a DES and a BMS in the same vessel. According to the type of stent implanted, patients were divided into BMS and DES groups. If a BMS and a DES were implanted in the same patient, but in different coronary arteries, the patient was assigned to the DES group.
Coronary angiography and PCI
Coronary angiography and PCI were performed at the physician’s discretion based on the clinical indication . The stent implanted (i.e. BMS or DES) was chosen at the operator’s discretion. Quantitative coronary angiography was performed to assess stenosis severity using the computer-based analysis system Siemens QuantCor QCA (ACOM.PC 5.01, Siemens Medical Systems Inc, Malvern, Pa). Minimal lumen diameter (MLD), per cent diameter stenosis, reference diameter, and lesion length were measured on end-diastolic angiographic frames. Acute lumen gain was the difference between MLD at the end of the intervention and MLD before balloon dilation. Pharmacological therapy, including platelet inhibitors, during the procedure and at discharge was prescribed according to the current guidelines . BMS were Driver ® Coronary System (Medtronic Vascular, Santa Rosa, CA) or PROKinetic ® Energy Stent System (BIOTRONIK AG, Bülach, Switzerland). DES were Cypher ® Stent (Cordis J&J, Bridgewater, New Jersey), Taxus ® Stent (Boston Scientific Corp., Natick, Massachusetts), Endeavor ® Stent (Medtronic Vascular, Santa Rosa, CA) and Xience V ® Stent (Abbott Vascular, CA, USA).
Data collection and follow-up
Clinical and procedural data were retrieved from the database of the Cardiovascular Center Aalst OLV Clinic, Aalst (Belgium). Clinical follow-up was carried out for up to 5 years using hospital records and telephone interviews. All events were classified and adjudicat ed by a physician not involved in the follow-up process. The primary endpoint of the study was major adverse cardiac events (MACE), defined as the composite of overall death, non-fatal re-infarction and TVR (repeated PCI plus coronary artery bypass graft surgery). Secondary endpoints were overall death, myocardial infarction, TVR, stent thrombosis (Academic Research Consortium definitions) and bleeding complications (Thrombolysis in Myocardial Infarction criteria) . This study complied with the Declaration of Helsinki and was approved by the local ethical committee. All patients provided written informed consent.
Statistical analysis
Continuous variables are expressed as mean ± standard deviation (SD) or median (interquartile range [IQR]). Categorical variables are reported as frequencies and percentages. Normal distribution was assessed by the Kolmogorov-Smirnov test. Student’s t test or the Mann-Whitney test was used to compare continuous variables, as appropriate. Comparisons between categorical variables were evaluated using two-tailed Fisher’s exact test or Pearson’s χ 2 test, as appropriate. To adjust for potential selection bias, a propensity score was built with a non-parsimonious method by the means of a logistic regression model relating stent group (DES vs. BMS) to pretreatment patient characteristics . Specifically, all the variables listed in Table 1 and the baseline angiographic characteristics included in Table 2 were incorporated into the model and the score was then used in proportional hazards analyses as a covariate. Survival was evaluated by the Kaplan−Meier method and Cox proportional hazard analysis. A P value of < 0.05 was considered statistically significant. All analyses were performed with SPSS version 16 (SPSS Inc, Chicago, Ill).
| BMS ( n = 175) | DES ( n = 118) | p | |
|---|---|---|---|
| Men | 96 (55) | 68 (58) | 0.64 |
| Age (years) | 82 ± 4 | 81 ± 4 | 0.007 |
| Body mass index (kg/m 2 ) | 26 ± 4 | 27 ± 4 | 0.02 |
| Ejection fraction (%) | 63 ± 17 | 62 ± 19 | 0.47 |
| Family history of CAD | 40 (23) | 30 (25) | 0.61 |
| Previous PCI | 54 (31) | 53 (45) | 0.01 |
| Previous CABG | 24 (14) | 21 (18) | 0.34 |
| CVD | 16 (9) | 13 (11) | 0.60 |
| PVD | 22 (13) | 16 (14) | 0.81 |
| Smoking | 59 (34) | 50 (42) | 0.13 |
| Diabetes mellitus | 16 (9) | 73 (62) | < 0.0001 |
| Hypertension | 121 (69) | 87 (74) | 0.40 |
| Hyperlipidaemia | 105 (60) | 75 (64) | 0.54 |
| Clinical presentation | |||
| Stable angina | 115 (66) | 76 (64) | 0.82 |
| UA/NSTEMI | 35 (20) | 31 (26) | 0.21 |
| STEMI | 25 (14) | 11 (9) | 0.20 |
| BMS ( n = 175) | DES ( n = 118) | p | |
|---|---|---|---|
| Multivessel PCI | 11 (6) | 14 (12) | 0.09 |
| Number of vessels treated | 1.1 ± 0.3 | 1.1 ± 0.3 | 0.16 |
| Stents implanted/patient | 1.3 ± 0.6 | 1.4 ± 0.6 | 0.41 |
| Coronary artery stented a | |||
| Left anterior descending | 82 (44) | 69 (52) | 0.14 |
| Left circumflex | 72 (39) | 45 (34) | 0.42 |
| Right coronary artery | 33 (18) | 18 (14) | 0.34 |
| Diameter stenosis (%) | 72.0 ± 14.3 | 73.2 ± 13.1 | 0.45 |
| RVD (mm) | 2.3 ± 0.3 | 2.2 ± 0.4 | 0.20 |
| MLD (mm) | 0.8 ± 0.3 | 0.7 ± 0.3 | 0.07 |
| Lesion length (mm) | 13.7 ± 7.5 | 17.1 ± 7.9 | 0.02 |
| Stent diameter (mm) | 2.6 ± 0.2 | 2.6 ± 0.1 | 0.88 |
| Stent length (mm) | 21.8 ± 11.8 | 26.9 ± 14.8 | < 0.001 |
| Acute lumen gain (mm) | 1.4 ± 0.5 | 1.5 ± 0.5 | 0.12 |
| Type of DES b | – | – | |
| ZES | – | 62 (41) | – |
| PES | – | 46 (30) | – |
| EES | – | 26 (17) | – |
| SES | – | 17 (11) | – |
| Other | – | 1 (1) | – |
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