Abstract
Background
Drug eluting stent (DES) failure including restenosis and stent thrombosis, or disease progression may result in target vessel revascularization (TVR) but the relative contribution of these mechanisms in the DES era is not well described. We sought to examine the predictors and presentations of patients with clinically driven TVR after DES.
Methods
Patients with all lesions treated with a DES in the Dynamic Registry from 2004 to 2006 were analyzed. Included were 2691 patients with 3401 lesions. Patients with and without incident clinically driven TVR at 2 years were compared according to baseline clinical, procedural, and angiographic characteristics and independent predictors of TVR and target lesion revascularization (TLR) were determined by multivariate analysis.
Results
By 2-years, TVR occurred in 7.2% of patients and TLR in 3.8%, with 71.6% and 82.5% of repeat revascularization events occurring in the first year, respectively. The indication for first TVR was myocardial infarction in 18.6% (n = 34), unstable angina in 42.6% (n = 78), stable coronary disease in 25.7% (n = 47) and other/unknown in 13.1% (n = 24). Disease progression was responsible for 47% of TVR. Among patients with TLR, restenosis was the mechanism in 86.6% and stent thrombosis in 13.4%. Independent predictors of TVR included younger age, diabetes, attempted graft lesion, lesion length > 30 mm and prior lesion intervention. Independent predictors of TVR and TLR were similar.
Conclusion
The incidence of clinically driven TVR is low in patients treated with DES and nearly half is attributable to disease progression, which along with the low rate of in-stent restenosis explains why the mode of presentation is often an acute coronary syndrome.
The effectiveness of drug-eluting stents (DES) in reducing in-stent restenosis and target lesion revascularization (TLR) has been demonstrated in many patient and lesion subsets . The reduction in restenosis has translated into fewer repeat revascularization procedures . Although several factors predict restenosis post DES implantation , DES failure may be due to several mechanisms including intimal hyperplasia within the stent, proximal or distal edge stenosis, or stent thrombosis. Disease progression of lesions remote from DES implantation also contributes to target vessel revascularization (TVR). Therefore, evaluating clinical and angiographic predictors of TVR may provide incremental value to assessing risk for restenosis alone and is the purpose of our analysis. Additionally, the clinical presentation of patients who experienced TVR after stenting with DES has not been well characterized and this was an additional aim of our study.
1
Methods
1.1
Study design and patient population
The National Heart, Lung, and Blood Institute-sponsored (NHLBI) Dynamic Registry is a prospective observational study of consecutive patients undergoing percutaneous coronary intervention (PCI) at 23 clinical centers in North America during specified time intervals. The study design has been previously described . This analysis includes patients enrolled from 2004 to2006 that had all lesions treated with DES. Patients were excluded if procedure or lesion forms from the repeat procedure were missing (n = 173) or if the patient had no TVR and was referred for coronary bypass surgery (n = 92). In these patients, the reason for TVR could not be determined. In total, 2691 patients with 3401 lesions were analyzed.
1.2
Data collection and definitions
Demographic, clinical, angiographic, and procedural data during the index hospitalization and 2-year follow-up events were collected by trained research coordinators who used standardized report forms and were guided by a manual of operations. All information was site determined. Two-year follow-up data were available in 2783 (94.8%) of patients that consented to follow-up. Patients without 2 year follow-up that were alive were censored at the time of their last follow up. During follow-up, coronary angiography was obtained as clinically indicated by symptoms or documentation of myocardial ischemia. Planned staged PCI was not considered a repeat PCI. Lesion specific data were collected for repeat PCI to determine target vessel revascularization. TVR was defined as any repeat PCI in the target vessel. TLR was defined as repeat PCI within the index procedure stent or 5 mm edge. Only definite stent thrombosis, defined as angiographically confirmed cases, is reported in this study. All stent thrombosis events were independently adjudicated.
1.3
Statistical analysis
The proportion of patients that had a TVR by 2 years according to the presence or absence of each baseline characteristics was determined. All variables were analyzed as categorical using chi- square test and Fisher exact test as appropriate. Two-year cumulative incidence rates of TVR and TLR were estimated by the Kaplan–Meier method and tested by the log-rank statistic. Independent predictors of TVR and TLR were determined by logistic regression analysis. Variables previously shown to be associated with TVR or TLR and those biologically relevant were included in the model. The Hosmer–Lemeshow goodness of fit test was performed and the p-value for the TVR logistic regression model was p = 0.27 indicating a good fit. We also performed the logistic regression analysis for predictors of TVR and TLR excluding patient with stent thrombosis and found similar results (data not shown).
2
Results
2.1
Baseline characteristics and TVR rates
Baseline clinical characteristics among patients treated with DES and stratified by the need for subsequent TVR are presented in Table 1 . Among patients age 65 and younger, 8.1% went on to require TVR compared to 5.2% of those over age 65 (p = 0.003). A repeat procedure for TVR occurred more often in patients with prior history of PCI, prior coronary bypass surgery, or diabetes at baseline. With respect to procedural and angiographic characteristics, significant differences in patients treated for TVR were observed based on the indication for PCI and lesion location ( Table 2 ). In addition, TVR was significantly associated with the treatment of lesions with a stent prior to the index PCI compared to those not previously treated with a stent. Furthermore, TVR was associated with the treatment of an index lesion located in an ostial position compared to non ostial location. Among lesions treated with a paclitaxel-eluting stent (PES), 5.6% experienced TVR and 94.4% did not. For sirolimus-eluting stent (SES) treated lesions, 7.4% experienced TVR and 92.6% did not (p = 0.05).
| Variable | Total number | No TVR % | TVR % | P value |
|---|---|---|---|---|
| Patients | 2691 | 93.2 | 6.8 | |
| Age over 65 | 0.003 | |||
| No | 1463 | 91.9 | 8.1 | |
| Yes | 1228 | 94.8 | 5.2 | |
| Female | 0.11 | |||
| No | 1805 | 93.7 | 6.3 | |
| Yes | 886 | 92.1 | 7.9 | |
| Prior Percutaneous Procedure(s) | < .0001 | |||
| No | 1805 | 94.5 | 5.5 | |
| Yes | 886 | 79.9 | 20.1 | |
| Prior brachytherapy | < .0001 | |||
| No | 2657 | 93.4 | 6.6 | |
| Yes | 34 | 76.5 | 23.5 | |
| Prior stent | < .0001 | |||
| No | 1944 | 94.4 | 5.6 | |
| Yes | 747 | 90.1 | 9.9 | |
| History of in-stent restenosis | 0.002 | |||
| No | 583 | 91.8 | 8.2 | |
| Yes | 165 | 83.6 | 16.4 | |
| Prior coronary bypass | < .0001 | |||
| No | 2193 | 94.0 | 6.0 | |
| Yes | 498 | 70.0 | 30.0 | |
| Prior myocardial infarction | 0.04 | |||
| No | 1984 | 93.8 | 6.3 | |
| Yes | 635 | 91.3 | 8.7 | |
| Diabetes | < .0001 | |||
| No | 1775 | 94.6 | 5.4 | |
| Yes | 913 | 90.5 | 9.5 | |
| History of congestive heart failure | 0.33 | |||
| No | 2386 | 93.4 | 6.6 | |
| Yes | 255 | 91.8 | 8.2 | |
| Hypertension | 0.06 | |||
| No | 588 | 94.9 | 5.1 | |
| Yes | 2079 | 92.7 | 7.3 | |
| Hypercholesterolemia | 0.03 | |||
| No | 559 | 95.2 | 4.8 | |
| Yes | 2059 | 92.6 | 7.4 | |
| Smoking | 0.0003 | |||
| Current | 626 | 93.9 | 6.1 | |
| Never/Former | 1907 | 85.6 | 14.4 | |
| Cerebrovascular disease | 0.83 | |||
| No | 2491 | 93.2 | 6.8 | |
| Yes | 195 | 92.8 | 7.2 | |
| Chronic kidney disease | 0.13 | |||
| No | 2433 | 93.4 | 6.6 | |
| Yes | 253 | 90.9 | 9.1 | |
| Peripheral vascular disease | 0.08 | |||
| No | 2458 | 93.4 | 6.6 | |
| Yes | 228 | 90.4 | 9.6 | |
| Pulmonary disease | 0.69 | |||
| No | 2459 | 93.1 | 6.9 | |
| Yes | 227 | 93.8 | 6.2 |
| Variable | Total number | No TVR % | TVR % | P value |
|---|---|---|---|---|
| Patients | 2691 | 93.2 | 6.8 | |
| Primary reason for PCI | 0.04 | |||
| Acute myocardial infarction | 754 | 95.1 | 4.9 | |
| Unstable angina | 920 | 91.3 | 8.7 | |
| Stable angina | 571 | 92.5 | 7.5 | |
| Asymptomatic CAD | 361 | 94.7 | 5.3 | |
| Number of Lesions Attempted | 0.44 | |||
| 1 | 2095 | 93.6 | 6.4 | |
| 2 | 498 | 92.2 | 7.8 | |
| 3 | 83 | 90.4 | 9.6 | |
| 4 | 14 | 85.7 | 14.3 | |
| 5 | 1 | 100.0 | 0.0 | |
| Ejection fraction | 0.09 | |||
| Less than 45 | 448 | 95.1 | 4.9 | |
| At least 45 | 1551 | 92.8 | 7.2 | |
| Lesions | 3401 | 92.8 | 7.2 | |
| Lesion location | < .0001 | |||
| Right coronary | 1060 | 93.5 | 6.5 | |
| Left main | 43 | 95.3 | 4.7 | |
| Left anterior descending | 1267 | 93.7 | 6.3 | |
| Left circumflex | 813 | 93.2 | 6.8 | |
| Saphenous vein graft | 218 | 82.6 | 17.4 | |
| Lesion previously stented | < .0001 | |||
| No | 3180 | 93.5 | 6.5 | |
| Yes | 216 | 83.3 | 16.7 | |
| Reference vessel size | 0.46 | |||
| Diameter less than 2.5 mm | 132 | 90.2 | 9.8 | |
| Diameter between 2.5 mm and 3 mm | 1926 | 92.9 | 7.1 | |
| Diameter more than 3 mm | 1211 | 93.1 | 6.9 | |
| Total Occlusion | 0.16 | |||
| No | 3093 | 92.6 | 7.4 | |
| Yes | 308 | 94.8 | 5.2 | |
| Calcified | 0.88 | |||
| No | 2347 | 92.8 | 7.2 | |
| Yes | 1000 | 92.7 | 7.3 | |
| Bifurcation | 0.66 | |||
| No | 3054 | 92.9 | 7.1 | |
| Yes | 334 | 92.2 | 7.8 | |
| Ostial lesion | 0.003 | |||
| No | 3124 | 93.2 | 6.8 | |
| Yes | 277 | 88.4 | 11.6 | |
| Paclitaxel-eluting stent | 0.09 | |||
| No | 1802 | 92.6 | 7.4 | |
| Yes | 889 | 94.4 | 5.6 | |
| Sirolimus-eluting stent | 0.05 | |||
| No | 824 | 94.7 | 5.3 | |
| Yes | 1867 | 92.6 | 7.4 |
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