Percutaneous intervention of a coronary graft is the treatment of choice when the graft fails. The objective is to report the long-term results of drug-eluting stents (DES) in mammary artery grafts (MAG). Patients who had been treated with DES for MAG in 27 centers were selected. The baseline and procedural clinical data were included prospectively, and the follow-up was performed with the patients, families, and medical records. Two hundred and sixty-eight patients were included: age 65.5 ± 10.1 years, diabetes 47.8%, ejection fraction 55.5 ± 14.9%. Indication: stable angina 28.4%, unstable angina 38.1%, non–ST-elevation myocardial infarction 21.6%, ST-elevation myocardial infarction 5.3%, and heart failure 6.7%; 1.19 ± 0.59 stents/patient were implanted measuring 18.8 ± 8.8 mm in length and 2.68 ± 0.35 mm in diameter. Rapamycin was used in 78 cases (29.1%), paclitaxel in 77 (28.7%), everolimus in 70 (26.1%), zotarolimus in 34 (12.7%), and biolimus in 9 (3.4%). All cases were successful except for 1 in which the patient died 30 minutes after the procedure. There were no other inhospital events. After a follow-up of 41 months (Q 25 : 23.7 to Q 75 : 57.8), 24 patients (9%) died of heart-related causes and 20 (7.5%) of noncardiac causes. Repeat revascularization was necessary in 31 cases, and in 1 additional patient, there was total occlusion, which was not treated. These 32 patients represented 11.9% of the total. In conclusion, the implantation of DES in MAG shows very high procedural success and also low long-term event rates.
Percutaneous coronary intervention (PCI) with drug-eluting stents (DES) is the procedure of choice for coronary graft lesions. Although there are plenty of reports in the literature of DES in vein grafts, there are not many for DES in mammary artery grafts (MAG). Data from saphenous grafts should not be extrapolated to MAG because of different sizes or characteristics of the lesions, and there is evidence of different behavior as that balloon PCI in MAG, contrary to what occurs with saphenous veins, can have better results than those obtained with bare metal stents (BMS). It is important to gain more in-depth knowledge in this field as the percentage of patients who receives MAG has increased notably: from 1988 to 2008, they represented only 1/3 of surgical revascularization procedures, whereas now they are over 90%. The objective of the study was to analyze the inhospital and long-term results of DES in MAG in a cohort of consecutive patients from 27 hospital centers.
Methods
An observational study of a cohort of patients treated consecutively with at least 1 DES in a lesion affecting an MAG. Twenty-seven centers were contacted in Spain to obtain the data of patients treated from 2003 to 2011.
We selected all the patients who had received at least 1 DES in an MAG on the date indicated from 27 centers in Spain. The clinical and procedural characteristics had been introduced prospectively at the time of PCI. The data relating to follow-up were obtained from the medical records and by contacting the patients, their first-degree relatives, and referring doctors. Patients who had undergone PCI in the first month after surgery because of acute graft failure were analyzed as a subgroup. All the patients were advised to continue the double antiplatelet therapy for 12 months. We analyzed the all-cause mortality and vessel failure, described as significant stent restenosis requiring vessel revascularization or total occlusion of the graft.
The continuous variables are expressed as mean and standard deviation and the qualitative variables as proportions. The Kaplan–Meier method was used to analyze the long-term survival and to compare the rate of vessel failure between the first- and second-generation DES. A Cox regression analysis was performed to determine if any characteristic would predict the need for revascularization, and the SPSS 17.0 statistical package was used in the calculations.
Results
A total of 268 patients aged 65.5 ± 10.1 years was included. Table 1 provides the patient characteristics and Table 2 provides the characteristics of the lesions and the data relating to the procedure. None of the patients had 2 different types of DES.
| n=268 | |
|---|---|
| Age (Years) | 66.5 ± 10.1 |
| Female gender | 60 (22.4 %) |
| Diabetes Mellitus | 128 (47.1 %) |
| Hypertension | 191 (71.3 %) |
| Hypercholesterolemia | 179 (66.8 %) |
| Smoker | 129 (48.1 %) |
| Previous myocardial infarction | 115 (42.9 %) |
| Previous percutaneous intervention | 79 (29.5 %) |
| Ejection fraction (%) | 55.5 ± 14.9 |
| Ejection fraction ≤ 30% | 28 (10.4 %) |
| Number of narrowed coronary arteries | |
| 1 | 20 (7.5 %) |
| 2 | 62 (23.1 %) |
| 3 | 186 (69.4 %) |
| Indication of catheterization | |
| Stable angina pectoris | 76 (28.4 %) |
| Unstable angina pectoris | 102 (38.1 %) |
| Non ST-elevation myocardial infarction | 58 (21.6 %) |
| ST-elevation myocardial infarction | 9 (3.4 %) |
| Sudden cardiac death | 5 (1.9 %) |
| Heart failure | 18 (3.7 %) |
| Months between surgery and percutaneous intervention | 35 (Q 25 4.1 – Q 75 111) |
| Percutaneous intervention in the first 30 days after surgery | 21 (7.8 %) |
| n=268 | |
|---|---|
| Right internal mammary | 19 (7.1 %) |
| Vessel connected to the graft | |
| Left anterior descending | 257 (95.9 %) |
| Left circumflex | 8 (3 %) |
| Right coronary artery | 3 (1.1 %) |
| Segment | |
| Anastomosis | 217 (81 %) |
| Body | 36 (13.4 %) |
| Proximal | 15 (5.6 %) |
| Lesions in restenosis | 21 (7.8 %) |
| Initial TIMI flow | |
| 0 | 8 (3 %) |
| 1 | 21 (7.8 %) |
| 2 | 23 (8.6 %) |
| 3 | 216 (80.6 %) |
| Direct stenting | 94 (35.1 %) |
| Stent per lesion | 1.19 ± 0.59 |
| 1 | 227 (84.7 %) |
| 2 | 33 (12.3 %) |
| ≥ 3 | 8 (3.1 %) |
| Stent diameter (mm) | 2.68 ± 0.35 |
| Stent length (mm) | 18.8 ± 8.7 |
| Stent types | |
| Rapamycin | 78 (29.1 %) |
| Paclitaxel | 77 (28.7 %) |
| Everolimus | 70 (26.1 %) |
| Zotarolimus | 34 (12.7 %) |
| Biolimus | 9 (3.4 %) |
| Pressure (atmospheres) | 14.3 ± 2,4 |
| Postdilatation | 37 (13.8 %) |
| Final TIMI flow | |
| 0 | 1 (0.4 %) |
| 1 | 2 (0.7 %) |
| 2 | 2 (0.7 %) |
| 3 | 263 (98.2 %) |
| IIb-IIIa inhibitors | 19 (7.1 %) |
The procedure was successful in 263 patients (98.2%), whereas in 1 case, there was final Thrombolysis In Myocardial Infarction (TIMI) flow grade 0, in 2 cases TIMI flow grade 1, and in another 2 TIMI flow grade 2. The TIMI 0 patient died half an hour after the procedure. No other patients died, nor were there any repeat revascularizations while in hospital. After a follow-up of 41 months (Q 25 : 23.7 to Q 75 : 57.8), 24 patients (9%) had died of heart-related causes and 20 (7.5%) of noncardiac causes with survival at 12, 24, 36, and 48 months of 94 ± 1.5%, 91.7 ± 1.8%, 87 ± 2.3%, and 80.2 ± 3%, respectively ( Figure 1 ). There were no differences in mortality between unstable angina, non–ST-elevation myocardial infarction, and ST-elevation myocardial infarction but compared with the patients with stable angina, those with acute coronary syndromes showed higher long-term mortality rate (11.7% vs 24.2%, p = 0.05). Five patients (1.8%) were lost to follow-up. Repeat revascularization was necessary in 31 cases, and in 1 additional patient, there was total occlusion of the MAG, which was not treated. These 32 patients represent 11.9% of the total. The stents implanted in these 32 patients eluted rapamycin in 11 cases, paclitaxel in 12, everolimus in 6, and zotarolimus in 3, with vessel failure rates with regard to the number of stents implanted of 14.1%, 15.6%, 8.5%, and 8.8%, respectively. Figure 2 compares the behavior of the first-generation stents with that of the second-generation ones. In the multivariate analysis, the variables diabetes, restenotic lesion, anastomosis, stent diameter, stent length, number of stents, and the type of stent were included. The restenotic character (relative risk [RR] 6.4, 95% confidence interval [CI] 2.6 to 15.9, p <0.0001) and number of stents (RR 1.7, 95% CI 1.12 to 2.58, p = 0.011) were related with the need of revascularization, whereas the type of stent (first vs second generation, RR 2.21, 95% CI 0.98 to 5.1, p = 0.055) and lesion located in the anastomosis versus ostium or shaft (RR 3.2, 95% CI 0.87 to 11.7, p = 0.08) showed tendency and probably with a greater number of patients also would have been present in the final model. Table 3 provides the inhospital and follow-up results.
| n = 268 | |
|---|---|
| In-hospital target vessel revascularization | 0 |
| In-hospital death | 1 |
| Survival at 24 months | 91.7 ± 1.8 % |
| Deaths at follow-up | 44 (16.5 %) |
| Cardiac | 24 (9 %) |
| Non-cardiac | 20 (7.5 %) |
| Stroke | 3 (1.1 %) |
| Cancer | 7 (2.6 %) |
| Kidney-related | 2 (0.7 %) |
| Respiratory | 3 (1.2 %) |
| Sepsis | 5 (1.9 %) |
| Vessel failure | 32 (11.9 %) |
| Origin | 0 |
| Shaft | 3 (8.3 %) |
| Anastomosis | 29 (13.3 %) |
| Follow-up (months) | 41 (Q 25 23.7 – Q 75 57.8) |
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