The endothelial progenitor cell (EPC)-capture stent promotes endothelialization and preliminary studies have suggested its safety and feasibility in ST-elevation myocardial infarction (STEMI). Detailed late clinical follow-up and angiographic analyses are, however, limited. We sought to determine late angiographic and clinical outcomes of the Genous EPC-capture stent in primary angioplasty. EPC-capture stents were implanted during primary angioplasty in 489 consecutive patients presenting with STEMI from 2004 through 2008. The first 100 consenting patients undergoing successful stent implantation scheduled to undergo relook coronary angiography at 6 to 12 months were enrolled. Ninety-five patients with 96 lesions were analyzed independently. Mean duration of follow-up coronary angiography was 245 days. In-stent late luminal loss measured 0.87 ± 0.67 mm. Binary restenosis (defined as >50% diameter stenosis) was 28%, with diffuse in-stent restenosis (Mehran class II) as the predominant pattern. Of 27 patients with binary restenosis, 14 (52%) were symptomatic, with 10 patients undergoing target lesion revascularization. Asymptomatic patients had significantly larger reference vessel and in-stent minimal luminal diameters (2.77 ± 0.39 vs 2.54 ± 0.44 mm, p = 0.040; 2.74 ± 0.34 vs 2.31 ± 0.72 mm, p = 0.004, respectively). Follow-up late loss and diameter stenoses were also in favor of the asymptomatic group. Major adverse cardiac event rate was 16% at a mean follow-up of 34 months. There were no cases of Academic Research Consortium–defined stent thrombosis. In conclusion, implantation of the EPC-capture stent during primary angioplasty is associated with a favorable late clinical outcome but with higher than anticipated angiographic late loss.
In our institution, the Genous endothelial progenitor cell (EPC)-capture stent has been used routinely in patients with ST-elevation myocardial infarction (STEMI) without cardiogenic shock since 2004. We have published data supporting its utility in this setting. Other investigators have similarly substantiated its safety in this and other high-risk settings. Although clinical outcome has been favorable, this has been restricted to relatively short-term follow-up. There is a paucity of data on its late loss, an angiographic index that has been proposed to be a more efficient estimate of in-stent restenosis in this era of low binary restenosis rates. To compare its long-term restenosis rate with drug-eluting stents, angiographic data and in particular late loss measurements are necessary. We evaluated angiographic findings and long-term clinical outcomes of patients with STEMI treated with the Genous EPC-capture stent.
Methods
At our institution, all patients undergoing primary angioplasty for STEMI but no cardiogenic shock have been treated with the Genous EPC-capture stent (OrbusNeich, Wanchai, Hong Kong) since late 2004. Primary angioplasty was performed according to standard practice. The detailed interventional strategy was left to the discretion of the individual operator. Weight-adjusted heparin was administered to achieve an activated clotting time >300 seconds or 200 to 250 seconds when platelet glycoprotein IIb/IIIa inhibitors were used. After stent implantation, patients were prescribed lifelong aspirin (100 mg/day) and clopidogrel (75 mg daily) for 1 month. The local ethics committee approved the study protocol and informed consent was obtained from all patients.
From June 2004 through April 2008, 489 patients with STEMI received this stent and were followed up clinically. Angiographic follow-up at 6 to 12 months was proposed for these patients and our intent was to analyze follow-up angiographic findings of the first 100 consenting patients from this cohort. Symptomatic and asymptomatic patients were considered.
Angiographic follow-up and clinical adjudication were conducted in blinded fashion by an independent core laboratory (Cardiovascular Research Foundation, New York, New York). Quantitative coronary angiography was performed in the standard fashion and binary restenosis was defined as >50% diameter stenosis. Patients were followed clinically until February 2010 for the development of major adverse cardiac events (MACEs), defined as repeat target vessel revascularization, acute MI, and cardiac death.
Statistical analysis was performed using STATA 9.2 (STATA Corporation, College Station, Texas). Discrete data were presented as frequencies and/or percentages and continuous variables were presented as means ± SDs. Mann–Whitney 2-sample Wilcoxon rank-sum test was used to compare angiographic measurements between symptomatic and asymptomatic patients. A p value <0.05 was used to indicate statistical significance.
Results
Ninety-five patients with 96 lesions were subsequently analyzed. Although we had intended 100 patients, 5 patients were excluded because their follow-up coronary angiograms were outside the prespecified stipulated window period of 6 to 12 months. Mean duration of follow-up coronary angiography was 245 ± 62 days. Clinical characteristics of these 95 patients are presented in Table 1 .
| Age (years), mean ± SD | 54 ± 10 |
| Men | 94% |
| Diabetes mellitus | 29% |
| Hypertension | 50% |
| Hypercholesterolemia ⁎ | 76% |
| Smoker | 65% |
| Family history of premature coronary heart disease | 7.3% |
| Coronary artery involved | |
| Left anterior descending artery coronary artery | 58% |
| Left circumflex artery | 6% |
| Right coronary artery | 35% |
| Left main coronary artery | 1% |
⁎ Defined as previous use of a statin drug, total cholesterol level ≥6.2 mmol/L, or low-density lipoprotein level ≥3.4 mmol/L.
Glycoprotein IIb/IIIa inhibitors were used in 29 patients (30%). Fifty-three patients (56%) underwent balloon dilation before stent implantation. Similarly, 53 patients underwent thrombus aspiration alone as a prelude to stenting. Twenty-eight patients (29%) had thrombus aspiration and balloon dilation before stent implant. Average stent diameter and stent segment length were 2.96 ± 0.33 and 23.00 ± 9.58 mm, respectively. Eighty-eight patients required just 1 stent, whereas 2 patients required implantation of 3 overlapping Genous stents for a diffuse lesion. Four patients required 2 overlapping stents for diffuse lesions and 1 patient required 2 stents at 2 discrete stenoses of the culprit artery.
Coronary angiographic findings at presentation are presented in Table 2 . After primary angioplasty, 86 patients (91%) had restored Thrombolysis In Myocardial Infarction grade 3 flow, 8 patients (8%) had grade 2 flow, and only 1 patients (1%) had grade 0 flow after the procedure.
| Before primary angioplasty | |
| Diameter of reference vessel (mm) | 2.68 ± 0.52 |
| Minimal luminal diameter (mm) | 0.14 ± 0.27 |
| Diameter stenosis (%) | 95 ± 9 |
| Immediately after primary angioplasty | |
| Diameter of reference vessel (mm) | 2.73 ± 0.41 |
| Minimal luminal diameter (mm) | |
| In stent | 2.66 ± 0.46 |
| In segment | 2.28 ± 0.45 |
| Diameter stenosis (%) | 17 ± 12 |
| Follow-up coronary angiography | |
| Diameter of reference vessel (mm) | 2.87 ± 0.38 |
| Minimal luminal diameter (mm) | |
| In stent | 1.79 ± 0.71 |
| In segment | 1.71 ± 0.67 |
| Late luminal loss (mm) | |
| In stent | 0.87 ± 0.67 |
| In segment | 0.56 ± 0.62 |
| Diameter stenosis (%) | 39 ± 22 |
| Binary restenosis >50% diameter stenosis (%) | 28 |
Cardiac echocardiography performed after the intervention showed a median left ventricular ejection fraction of 47% (interquartile range 18) in the cohort. Median peak creatine kinase measured 2,754 U/L (interquartile range 3,012), and 82% of patients had complete resolution of ST-segment elevation after the intervention.
At follow-up coronary angiography, mean diameter stenosis measured 39% and in-stent late luminal loss measured 0.87 ± 0.67 mm ( Table 2 ). In-stent restenosis patterns in 27 patients with binary restenosis are presented in Table 3 .
| Focal margin in-stent restenosis (Mehran class IB) | 4 (15%) |
| Focal body in-stent restenosis (Mehran class IC) | 1 (4%) |
| Diffuse in-stent restenosis (Mehran class II) | 17 (62%) |
| Proliferative in-stent restenosis (Mehran class III) | 4 (15%) |
| Total occlusion in-stent restenosis (Mehran class IV) | 1 (4%) |
Because symptomatic patients were more inclined to undergo relook coronary angiography, we also considered angiographic findings when these patients were excluded. Of 95 patients evaluated, 79 (82%) were asymptomatic. Repeat analysis of these 79 asymptomatic patients showed similar findings ( Table 4 ).
| p Value | ||
|---|---|---|
| Before primary angioplasty | ||
| Diameter of reference vessel (mm) | 2.69 ± 0.54 | |
| Minimal luminal diameter (mm) | 0.13 ± 0.25 | |
| Diameter stenosis (%) | 95 ± 9 | |
| Immediately after primary angioplasty | ||
| Diameter of reference vessel (mm) | 2.77 ± 0.39 | |
| Minimal luminal diameter (mm) | ||
| In stent | 2.74 ± 0.34 | |
| In segment | 2.32 ± 0.38 | |
| Diameter stenosis (%) | 16 ± 8 | |
| Follow-up coronary angiography | ||
| Diameter of reference vessel (mm) | 2.87 ± 0.38 | |
| Minimal luminal diameter (mm) | ||
| In stent | 1.93 ± 0.65 | |
| In segment | 1.86 ± 0.60 | |
| Late luminal loss (mm) | ||
| In stent | 0.81 ± 0.60 | |
| In segment | 0.46 ± 0.54 | |
| Diameter stenosis (%) | 33 ± 18 | |
| Binary restenosis >50% diameter stenosis (%) | 16 | |
| Angiographic parameters different from symptomatic patients | ||
| Postangioplasty reference vessel diameter (mm) | 2.77 ± 0.39 vs 2.54 ± 0.44 | 0.040 |
| Postangioplasty in-stent minimal luminal diameter (mm) | 2.74 ± 0.34 vs 2.31 ± 0.72 | 0.004 |
| Follow-up in-stent minimal luminal diameter (mm) | 1.93 ± 0.65 vs 1.17 ± 0.63 | <0.001 |
| Follow-up in-segment minimal luminal diameter (mm) | 1.86 ± 0.60 vs 1.05 ± 0.59 | <0.001 |
| Follow-up in-stent late loss (mm) | 0.81 ± 0.60 vs 1.14 ± 0.92 | 0.021 |
| Follow-up in-segment late loss (mm) | 0.46 ± 0.54 vs 1.01 ± 0.78 | <0.001 |
| Follow-up diameter stenosis (%) | 33 ± 18 vs 64 ± 19 | <0.001 |
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