This study investigates clinical outcomes after drug-coated balloon (DCB) treatment for in-stent restenosis (ISR) based on the angiographic result achieved after predilatation and before DCB treatment. Among ISR lesions treated with DCBs, 166 lesions with angiography immediately after predilatation were analyzed. The lesions were divided into 2 groups according to angiographic results after predilatation: (1) “adequate” defined as the presence of Thrombolysis In Myocardial Infarction 3 flow, residual stenosis ≤30%, and no major dissections (n = 98 lesions) or (2) “inadequate” (n = 68 lesions). The reference vessel diameters were larger (2.88 ± 0.39 vs 2.64 ± 0.52 mm, p = 0.001) and lesion lengths shorter in the adequate group (15.4 ± 11.2 vs 19.7 ± 13.9 mm, p = 0.04). During a median follow-up of 808 days, the cumulative target lesion revascularization (TLR) rate was lower in the adequate group (20.3% vs 35.5% at 2 years; p = 0.04). Multivariate analysis indicated that an angiographically inadequate result before DCB treatment was an independent predictor of TLR, even after adjusting for reference vessel diameter and lesion length (hazard ratio 1.99, 95% confidence interval 1.02 to 3.87, p = 0.04). In conclusion, angiographic results after lesion preparation appear to be a good predictor of TLR after DCB treatment for ISR.
Despite remarkable improvements in stent design and the development of drug-eluting stents (DESs), in-stent restenosis (ISR) still remains one of the major clinical problems in the percutaneous coronary intervention field. Currently, DESs and drug-coated balloons (DCBs) are recommended as the first-line options for the treatment of bare-metal stent and DES-ISR. DCBs have distinct advantages, because of their ability to provide favorable results without adding a further metallic layer. Sufficient lesion preparation is believed to be important when using DCBs for ISR, and DCBs are generally recommended as a treatment option for lesions with adequate angiographic results after predilatation. However, limited data are available regarding this strategy. This study investigates outcomes after DCB treatment for ISR by focusing specifically on angiographic results immediately after predilatation.
Methods
A total of 198 ISR lesions were treated with DCBs in 2 high-volume centers in Milan, Italy, from May 2009 to June 2014. Lesions treated without predilatation before DCB (n = 22) or those in which the angiographic images immediately after predilatation were not analyzable (n = 10) were excluded. The remaining 166 lesions were divided into 2 groups according to the angiographic assessment immediately after predilatation ( Figure 1 ): (1) an “adequate” group defined as the presence of Thrombolysis In Myocardial Infarction 3 flow, residual stenosis ≤30%, and no major dissections or (2) an “inadequate” group when at least 1 of the parameters used to define the adequate group was absent. Major dissections were defined as dissection types C to F. All patients provided informed consent for both the procedure and subsequent data collection and/or analysis.
The percutaneous coronary intervention strategy was dependent on the individual operator; however, general principles included predilatation (balloon-to-vessel ratio of 0.8 to 1.0, and/or 1:1 with previous stent) performed with noncompliant balloons inflated to high pressures (>18 atm). DCBs were inflated at nominal pressure for a minimum of 30 to 60 seconds to allow drug delivery to the vessel wall, using the following paclitaxel coated balloons: IN.PACT Falcon (Medtronic Inc., Minneapolis, Minnesota); Pantera Lux (BIOTRONIK AG, Bülach, Switzerland); and Dior (Eurocor GmbH, Bonn, Germany). Patients received dual-antiplatelet therapy for a minimum of 1 month after procedure.
Clinical follow-up was performed by clinical visits, telephone interviews, and from hospital records of any readmissions. Target lesion revascularization (TLR) was primarily examined. Other end points included cardiac death, target vessel myocardial infarction, and definite or probable stent thrombosis.
TLR was defined as repeat percutaneous coronary intervention or coronary artery bypass grafting for the target lesion or in the adjacent proximal or distal 5 mm. Myocardial infarction was defined as an elevation of cardiac biomarker values above the upper limit in combination with at least 1 of the following: new onset of ischemic symptoms, electrocardiographic changes indicating new ischemia, development of new pathologic Q waves on the electrocardiogram, imaging evidence of a new loss of viable myocardium or new regional wall motion abnormality, or identification by angiography or autopsy. Stent thrombosis was defined according to the Academic Research Consortium criteria.
Focal patterns of ISR were defined as Mehran classes IA to ID, and diffuse pattern classes II to IV. Quantitative coronary angiography analyses were performed using a validated edge detection system (CMS version 5.2; Medis Medical Imaging Systems BV, Leiden, The Netherlands). The following parameters were measured: reference vessel diameter, minimal lumen diameter, percentage diameter stenosis, and acute gain.
Data are presented as mean ± SD or median (interquartile range). Categorical variables are expressed as number and percentages. Continuous data were compared using the unpaired t test. Categorical data were compared using the chi-square or Fisher exact tests. Cumulative event rates in each group were analyzed using Kaplan–Meier methods, and rate differences between the groups estimated using the log-rank test. Hazard ratios and 95% confidence intervals were calculated for each factor using Cox univariate analysis. Cox multivariate analysis was performed to determine independent predictors of TLR. Factors with a p value <0.1 on univariate analysis and judged to be of clinical significance were entered into the multivariate Cox regression analysis. A p value <0.05 was considered statistically significant. All analyses were performed using the SPSS 21.0 software package (SPSS, Chicago, Illinois).
Results
Among the 166 lesions analyzed, 98 lesions were classified into the adequate group, with the remaining 68 lesions into the inadequate group. The baseline patient characteristics are shown in Table 1 . There were no significant differences in regards to coronary risk factors including diabetes. Acute coronary syndrome, as an indication for percutaneous coronary intervention, was greater in the adequate group.
| Variable | Adequate (n = 69) | Inadequate (n = 54) | P-value |
|---|---|---|---|
| Age (years) | 67.1±9.8 | 68.1±8.4 | 0.54 |
| Men | 62 (90%) | 49 (91%) | 0.87 |
| Hypertension | 53 (77%) | 39 (72%) | 0.56 |
| Diabetes mellitus | 31 (45%) | 22 (41%) | 0.64 |
| Insulin use | 12 (17%) | 9 (17%) | 0.92 |
| Dyslipidemia | 53 (77%) | 34 (63%) | 0.09 |
| Family history of coronary artery disease | 32 (46%) | 32 (59%) | 0.16 |
| Current smoker | 5 (7%) | 6 (11%) | 0.46 |
| Prior myocardial infarction | 31 (45%) | 20 (37%) | 0.38 |
| Previous coronary artery bypass grafting | 15 (22%) | 14 (26%) | 0.59 |
| Left ventricular ejection fraction (%) | 52.3±10.3 | 54.3±7.4 | 0.26 |
| Acute coronary syndrome | 18 (26%) | 6 (11%) | 0.04 |
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