Although rotational atherectomy (RA) is used for complex lesions in percutaneous coronary intervention, there are several contraindications and precautions. The purpose of our study was to compare complications between off-label and on-label use of RA. We identified 250 consecutive patients who underwent RA. Off-label characteristics included saphenous vein graft lesions, presence of thrombus, unprotected left main stenosis, coronary artery dissection, acute myocardial infarction (MI), left ventricular dysfunction, 3-vessel disease, long lesion (≥25 mm), or angulated lesion (≥45°). Patients who had ≥1 off-label characteristic were assigned to the off-label group (156 patients), and patients who had no off-label characteristics were assigned to the on-label group (94 patients). Occurrence of slow flow or periprocedural MI in the off-label group was higher than that in the on-label group (slow flow 30% vs 18%, p = 0.06; MI 8.8% vs 2.1%, p = 0.04), whereas severe complications such as burr entrapment, transection of the guidewire, or perforation were rare in the 2 groups. In conclusion, compared to the on-label group, the off-label group had a higher incidence of slow flow and periprocedural MI. Severe complications such as burr entrapment, transection of the guidewire, or perforation were rare in the 2 groups.
Although rotational atherectomy (RA) is used for complex lesions in percutaneous coronary intervention, there are several contraindications and precautions in the directions-for-use document (Rotablator, Boston Scientific Corporation, Natick, Massachusetts) such as saphenous vein graft lesions, diffuse long lesions (≥25 mm), angulated lesions (≥45°) or thrombotic lesions. Despite these contraindications, RA is sometimes used for a lesion that cannot be dilated by conventional balloon angioplasty. Therefore, interventional cardiologists often use RA in contraindicated settings. We hypothesized that the risk of complications during off-label use of RA is higher than the risk during on-label use. Therefore, the purpose of our study was to compare the complications between off-label and on-label use of RA.
Methods
Nine off-label characteristics were identified from the directions-for-use document for RA : saphenous vein graft lesion, large thrombus, unprotected left main stenosis, culprit lesion of acute myocardial infarction (MI), large dissection, severe left ventricular dysfunction (ejection fraction <30%), severe 3-vessel disease, long lesion (≥25 mm), and angulated lesion (≥45°). We identified consecutive patients who underwent RA from our percutaneous coronary intervention database from January 1, 2008 through November 30, 2011. Patients who had ≥1 off-label characteristic were assigned to the off-label group, and patients who had no off-label characteristics were assigned to the on-label group.
Indications for RA in our institution are (1) moderate or severe calcified lesions, (2) diffuse lesions expected to be difficult to stent, and (3) ostial lesions. When treating culprit lesions of acute coronary syndrome (ACS), we do not use RA as the first-line strategy. However, we use RA for the culprit lesion for ACS, if needed.
Clinical criteria were defined as follows. Slow flow was defined as slow or absent distal runoff (Thrombolysis In Myocardial Infarction flow grade ≤2). Hypertension was defined as systolic blood pressure >140 mm Hg, diastolic blood pressure >90 mm Hg, or medical treatment for hypertension. Diabetes mellitus was defined as a hemoglobin A1c level >6.5% or treatment for diabetes mellitus. Hyperlipidemia was defined as a total cholesterol level >220 mg/dl, a low-density lipoprotein cholesterol level >140 mg/dl, or treatment for hyperlipidemia. ACS was defined as ST-segment elevation MI, non–ST-segment elevation MI, or unstable angina. Chronic total occlusion was defined as total occlusion ≥3 months. Reference diameter and lesion length were calculated by quantitative coronary angiographic analysis. Offline, computer-based software QAngio XA 7.1 (MEDIS Imaging Systems, Leiden, the Netherlands) was used for quantitative coronary angiographic analysis. Burr-to-artery ratio was defined as final burr size divided by reference diameter. This study was approved by the institutional review board at our institution.
RA was performed using standard techniques. Before the procedure, all patients received oral aspirin (≥81 mg). Ticlopidine (200mg) or clopidogrel (75 mg) was added when coronary stenting was performed. Intravenous heparin was used to achieve an appropriate activated coagulation time (≥250 seconds). We used 2 types of drug cocktails during RA. From the beginning of the study period (January 2008) to April 2010, we used a verapamil-based drug cocktail (verapamil 5 mg, isosorbide dinitrate 2.5 mg, heparin 10,000 U, and normal saline 500 ml). We switched from a verapamil-based drug cocktail to nicorandil-based drug cocktail because the results of clinical studies have favored a nicorandil-based cocktail. From April 2010 to the end of the study period (November 2011), we used a nicorandil-based cocktail (nicorandil 12 mg, isosorbide dinitrate 2.5 mg, heparin 10,000 U, and normal saline 500 ml).
Complications related to RA were defined as slow flow, burr entrapment, transection of the 0.009-inch RA guidewire, and vessel perforation from the burr. In slow-flow analysis, we excluded patients who did not have an appropriate cine angiogram to review the occurrence of slow flow. An appropriate cine angiogram did not show obstacles such as a balloon or microcatheter between RA and stenting. In-hospital outcomes were defined as periprocedural MI and in-hospital death. Periprocedural MI was defined as an increase in creatine kinase (at least threefold increase from normal upper limit).
Data are presented as percentage for categorical variables and mean ± SD for continuous variables. Occurrence of complications and in-hospital outcomes was compared between the off-label and on-label groups. Patient, lesion, and procedural characteristics were also compared between the off-label and on-label groups. The Kolmogorov–Smirnov test was performed to determine if the continuous variables were normally distributed. Normally distributed continuous variables were compared between groups using unpaired Student’s t test. Otherwise, continuous variables were compared using Mann–Whitney U test. Categorical data were compared using chi-square test. A p value <0.05 was considered statistically significant. All analyses were performed using SPSS 13.0 for Windows (SPSS, Inc., Chicago, Illinois).
Results
From January 1, 2008 through November 30, 2011, there were 250 patients treated by RA in our medical center. Because we did not exclude patients, 250 patients were included in our main analysis. Of 250 patients, 156 patients who had ≥1 off-label characteristic were assigned to the off-label group. The remaining 94 patients who did not have any off-label characteristics were assigned to the on-label group.
Patient, lesion, and procedural characteristics between the off-label and on-label groups are listed in Table 1 . There were no significant differences between the 2 groups in patient characteristics. Lesion length in the off-label group was significantly longer than that in the on-label group (28.4 ± 15.4 vs 13.7 ± 6.0, p <0.0001). Other lesion characteristics were not significantly different between the 2 groups. Minimum burr size in the off-label group was significantly smaller than that in the on-label group (1.52 ± 0.14 vs 1.57 ± 0.16, p = 0.03). Other procedural characteristics were not significantly different between the 2 groups. The distribution of off-label characteristics was heterogeneous ( Table 2 ). None of the patients had a saphenous vein graft lesion, large thrombus, or large dissection.
| Variable | All (n = 250) | On Label (n = 94) | Off Label (n = 156) | p Value |
|---|---|---|---|---|
| Patient characteristics | ||||
| Age (years) | 70 ± 9 | 70 ± 9 | 70 ± 9 | 0.52 |
| Men | 196 (78%) | 70 (75%) | 126 (81%) | 0.24 |
| Overweight (body mass index ≥25 kg/m 2 ) | 68 (27%) | 27 (29%) | 41 (26%) | 0.67 |
| Hypertension | 237 (95%) | 90 (96%) | 147 (94%) | 0.6 |
| Diabetes mellitus | 114 (46%) | 43 (46%) | 71 (46%) | 0.97 |
| Hyperlipidemia | 219 (88%) | 84 (89%) | 135 (87%) | 0.51 |
| Current smoker | 82 (33%) | 34 (36%) | 48 (31%) | 0.38 |
| Creatinine >2 mg/dl | 32 (13%) | 10 (11%) | 22 (14%) | 0.43 |
| Chronic renal failure on hemodialysis | 27 (11%) | 7 (7.4%) | 20 (13%) | 0.19 |
| Statin treatment | 208 (83%) | 80 (85%) | 128 (82%) | 0.53 |
| Systolic blood pressure before rotational atherectomy (mm Hg) | 142 ± 24 | 140 ± 21 | 142 ± 26 | 0.63 |
| Diastolic blood pressure before rotational atherectomy (mm Hg) | 73 ± 13 | 72 ± 13 | 74 ± 13 | 0.29 |
| Heart rate before rotational atherectomy (per minute) | 69 ± 16 | 69 ± 17 | 68 ± 16 | 0.47 |
| Lesion characteristics | ||||
| Culprit lesion in acute coronary syndrome | 32 (13%) | 8 (8.5%) | 24 (15%) | 0.12 |
| Chronic total occlusion | 21 (8.4%) | 7 (7.4%) | 14 (9.0%) | 0.67 |
| Target coronary artery | ||||
| Left anterior descending | 178 (71%) | 73 (78%) | 105 (67%) | 0.08 |
| Left circumflex | 19 (7.6%) | 6 (6.4%) | 13 (8.3%) | |
| Right | 44 (18%) | 15 (16%) | 29 (19%) | |
| Left main | 9 (3.6%) | 0 | 9 (5.8%) | |
| Reference diameter (mm) | 2.2 ± 0.7 | 2.3 ± 0.7 | 2.2 ± 0.6 | 0.14 |
| Lesion length (mm) | 22.8 ± 14.6 | 13.7 ± 6.0 | 28.4 ± 15.4 | <0.0001 |
| Procedural characteristics | ||||
| Final procedure | ||||
| Rotational atherectomy ± balloon | 2 (0.8%) | 0 | 2 (1.3%) | 0.24 |
| Rotational atherectomy + drug-eluting stent | 233 (93%) | 86 (92%) | 147 (94%) | |
| Rotational atherectomy + bare-metal stent | 15 (6.0%) | 8 (8.5%) | 7 (4.5%) | |
| Final procedure success | 250 (100%) | 94 (100%) | 156 (100%) | |
| Final burr size (mm) | 1.64 ± 0.20 | 1.65 ± 0.21 | 1.63 ± 0.20 | 0.36 |
| Minimum burr size (mm) | 1.54 ± 0.15 | 1.57 ± 0.16 | 1.52 ± 0.14 | 0.03 |
| Number of burrs used | 1.3 ± 0.4 | 1.2 ± 0.4 | 1.3 ± 0.5 | 0.09 |
| Total run time (seconds, n = 243) | 79 ± 64 | 69 ± 60 | 85 ± 66 | 0.06 |
| Single-run time (seconds, n = 243) | 15 ± 4 | 15 ± 4 | 15 ± 4 | 0.49 |
| Burr-to-artery ratio | 0.79 ± 0.25 | 0.78 ± 0.26 | 0.80 ± 0.25 | 0.39 |
| Nicorandil-based cocktail | 72 (29%) | 27 (29%) | 45 (29%) | 0.98 |
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