DIRECT: Direct Stenting Using the Sirolimus-Eluting Bx VELOCITY Stent
DIRECT: Direct Stenting Using the Sirolimus-Eluting Bx VELOCITY Stent
Presenter: Jeffrey Moses, MD, Lenox Hill Hospital (New York, NY)
Improving stent implantation techniques has become critical, especially with the advent of new and highly effective stents and delivery systems. The development of new systems with improved deliverability permits the treatment of more complex lesions avoiding balloon predilatation (direct stenting). Although limited, data indicate that compared to a predilatation strategy, a direct stenting approach is associated with less trauma to the vessel wall and reduced procedural time. However, there has been some hesitation in the medical community regarding a direct stent approach using the newly developed drug-eluting stents . The main concern behind this hesitation is that during direct stenting, the polymer coating with the drug could be scraped off the stent, thereby reducing its efficacy.
Aim
The aim of the Direct Stenting Using the Sirolimus-Eluting Bx VELOCITY Stent (DIRECT) trial was to assess the safety and efficacy of direct stenting using the sirolimus eluting Bx-VELOCITY (Cypher) stent (Cordis Corporation; Warren, New Jersey) and to compare outcomes of direct stenting with a mandatory predilatation strategy.
Primary Endpoint:
Secondary Endpoints:
DIRECT was a multicenter, prospective, nonrandomized trial in which a total of 225 patients underwent direct stenting with the Cypher stent. The outcomes of these patients were compared with those observed in the 412 patients from the angiographic cohort of the Sirolimus-Eluting Stent in De Novo Native Coronary Lesions (SIRIUS) trial who underwent Cypher stent implantation using the predilatation stent delivery strategy.
Results
Baseline characteristics were well balanced between the DIRECT study group and the historical control group. However, of particular note, patients in the direct stenting group had shorter lesions. The left anterior descending artery was the vessel most frequently treated (42%), and although there was a higher percentage of patients with ACC/AHA lesion Class C in the SIRIUS study, the percentage of patients with Class B2 and C lesions were similar in both groups (Table).
Table. DIRECT: Baseline Clinical and Lesion Characteristics
*P < .0001
ACC, American College of Cardiology; AHA, American Heart Association; LAD, left anterior descending; LCx, left circumflex; MI, myocardial infarction; PCI, percutaneous coronary intervention; RCA, right coronary artery; S/P, status post
Patients treated with the direct stenting technique received longer stents (22.6 mm vs 21.4 mm for the SIRIUS cohort; P = .04) that were deployed at higher pressures (15.5 atm vs 14.0 atm, respectively; P < .001). Given the shorter lesion lengths in the direct stenting group, the total stent length to lesion length ratio in the direct stenting group was 2:1 vs 1:6 in the predilatation group (P = .001). The use of glycoprotein IIb/IIIa inhibitors was similar in the 2 groups, as was final balloon diameter (3.3 mm).
Device success, lesion success, and procedural success were high and similar in both groups. Cypher delivery to the target site without predilatation was possible in 86% of patients, and procedural time was reduced by 12 minutes (33 min vs 45 min, respectively; P < .001) using this approach. Procedural complications, such as abrupt closure, dissection, no-reflow, distal embolization, perforation, thrombus, and spasm rates were lower in the direct stenting arm, although the difference did not reach statistical significance (composite 1.4% vs 3.7%, respectively; P = .23).
There were no significant differences in the incidence of clinical events (death, MI, TVR, TLR, and TVF) at 6-month follow-up between the 2 groups (Figure 1). Late loss was characteristically low and similar in both groups (0.18 mm), as was the incidence of late stent thrombosis (< 0.4%) and in-stent and in-lesion binary restenosis rates at 8 months (Figure 2).
Figure 1. DIRECT: Clinical events at 6-month follow-up.
Figure 2. DIRECT: In-stent and in-lesion binary restenosis rates at 8-month follow-up.
It is important to note that only 76% of patients in the direct arm underwent angiographic follow-up at 8 months compared with 87% in the SIRIUS study. When subgroup analysis was performed in diabetic patients, there was a trend toward lower restenosis rates in diabetic patients who underwent direct stenting (Figure 3). Further subgroup analysis found that although there was no difference in the rate of in-lesion binary restenosis among patients with non-insulin-dependent diabetes treated with or without direct stenting, the restenosis rates were significantly lower in patients with insulin-dependent diabetes who were treated with a direct stenting approach than in a similar group of patients treated with a predilatation strategy (Figure 4).
Figure 3. DIRECT: Diabetes subgroup -- in-stent and in-lesion binary restenosis rates at 8-month follow-up.
Figure 4. DIRECT: Diabetes subgroup – in-lesion binary restenosis in insulin-dependent vs non-insulin-dependent patients.
Conclusions
The investigators drew the following conclusions from this study:
The use of direct stenting has been a strong matter of debate in the medical community, and is mainly based on personal preference and experience. This study confirms what was shown in a subgroup analysis from the SIRIUS trial. In the present study, direct stenting was successful in a high percentage of patients and was associated with decreased procedural time and a trend toward a lower rate of intraprocedural complications. Of particular interest are the favorable findings among patients with diabetes, which is a subgroup of patients that did not have good outcomes in the SIRIUS study.
There is no doubt that there are some caveats to the way this study was performed, particularly when considering that the data for the control group were collected early on in the drug-eluting stent experience and improvements in technique and general familiarity with the devices may have accounted for some of the improved outcomes in this more recent trial. In addition, the stent-to-lesion length ratio was longer in the direct stenting arm than in patients treated with a predilatation strategy, and some have argued that larger ratios are associated with better outcomes. Nevertheless, the findings from the DIRECT trial are an important step in making stent implantation a simpler and safer procedure.
Reference
Improving stent implantation techniques has become critical, especially with the advent of new and highly effective stents and delivery systems. The development of new systems with improved deliverability permits the treatment of more complex lesions avoiding balloon predilatation (direct stenting). Although limited, data indicate that compared to a predilatation strategy, a direct stenting approach is associated with less trauma to the vessel wall and reduced procedural time. However, there has been some hesitation in the medical community regarding a direct stent approach using the newly developed drug-eluting stents . The main concern behind this hesitation is that during direct stenting, the polymer coating with the drug could be scraped off the stent, thereby reducing its efficacy.
Aim
The aim of the Direct Stenting Using the Sirolimus-Eluting Bx VELOCITY Stent (DIRECT) trial was to assess the safety and efficacy of direct stenting using the sirolimus eluting Bx-VELOCITY (Cypher) stent (Cordis Corporation; Warren, New Jersey) and to compare outcomes of direct stenting with a mandatory predilatation strategy.
Primary Endpoint:
In-lesion late loss at 8 months
Secondary Endpoints:
Late loss and minimal lumen diameter at 8 months
Major adverse cardiac events
Target vessel failure (TVF), target lesion revascularization (TLR), target vessel revascularization (TVR) at 9 months
Binary restenosis at 8 months
Device, lesion, procedure, and delivery success
Procedural time
DIRECT was a multicenter, prospective, nonrandomized trial in which a total of 225 patients underwent direct stenting with the Cypher stent. The outcomes of these patients were compared with those observed in the 412 patients from the angiographic cohort of the Sirolimus-Eluting Stent in De Novo Native Coronary Lesions (SIRIUS) trial who underwent Cypher stent implantation using the predilatation stent delivery strategy.
Results
Baseline characteristics were well balanced between the DIRECT study group and the historical control group. However, of particular note, patients in the direct stenting group had shorter lesions. The left anterior descending artery was the vessel most frequently treated (42%), and although there was a higher percentage of patients with ACC/AHA lesion Class C in the SIRIUS study, the percentage of patients with Class B2 and C lesions were similar in both groups (Table).
Table. DIRECT: Baseline Clinical and Lesion Characteristics
| Direct stenting (n = 225) | SIRIUS Cohort (n = 412) | |
|---|---|---|
| Age (yrs) | 63 | 62 |
| Male (%) | 63 | 74 |
| Diabetes (%) | 31 | 26 |
| Smoker (%) | 59 | 21* |
| S/P MI (%) | 27 | 31 |
| S/P PCI (%) | 30 | 27 |
| Reference vessel diameter (mm) | 2.77 | 2.79 |
| Lesion length (mm) | 12.4 | 14.7* |
| LAD (%) | 43 | 43 |
| LCx (%) | 28 | 24 |
| RCA (%) | 28 | 32 |
| ACC/AHA Class A (%) | 13 | 7 |
| ACC/AHA Class B1 (%) | 29 | 37 |
| ACC/AHA Class B2 (%) | 43 | 29 |
| ACC/AHA Class C (%) | 15 | 27* |
ACC, American College of Cardiology; AHA, American Heart Association; LAD, left anterior descending; LCx, left circumflex; MI, myocardial infarction; PCI, percutaneous coronary intervention; RCA, right coronary artery; S/P, status post
Patients treated with the direct stenting technique received longer stents (22.6 mm vs 21.4 mm for the SIRIUS cohort; P = .04) that were deployed at higher pressures (15.5 atm vs 14.0 atm, respectively; P < .001). Given the shorter lesion lengths in the direct stenting group, the total stent length to lesion length ratio in the direct stenting group was 2:1 vs 1:6 in the predilatation group (P = .001). The use of glycoprotein IIb/IIIa inhibitors was similar in the 2 groups, as was final balloon diameter (3.3 mm).
Device success, lesion success, and procedural success were high and similar in both groups. Cypher delivery to the target site without predilatation was possible in 86% of patients, and procedural time was reduced by 12 minutes (33 min vs 45 min, respectively; P < .001) using this approach. Procedural complications, such as abrupt closure, dissection, no-reflow, distal embolization, perforation, thrombus, and spasm rates were lower in the direct stenting arm, although the difference did not reach statistical significance (composite 1.4% vs 3.7%, respectively; P = .23).
There were no significant differences in the incidence of clinical events (death, MI, TVR, TLR, and TVF) at 6-month follow-up between the 2 groups (Figure 1). Late loss was characteristically low and similar in both groups (0.18 mm), as was the incidence of late stent thrombosis (< 0.4%) and in-stent and in-lesion binary restenosis rates at 8 months (Figure 2).
It is important to note that only 76% of patients in the direct arm underwent angiographic follow-up at 8 months compared with 87% in the SIRIUS study. When subgroup analysis was performed in diabetic patients, there was a trend toward lower restenosis rates in diabetic patients who underwent direct stenting (Figure 3). Further subgroup analysis found that although there was no difference in the rate of in-lesion binary restenosis among patients with non-insulin-dependent diabetes treated with or without direct stenting, the restenosis rates were significantly lower in patients with insulin-dependent diabetes who were treated with a direct stenting approach than in a similar group of patients treated with a predilatation strategy (Figure 4).
The investigators drew the following conclusions from this study:
In this analysis of the DIRECT multicenter trial, direct stenting was noninferior to predilatation for all endpoints assessed.
This approach reduced procedural time by a median of 12 minutes.
There was a trend toward reduced intraprocedural complications.
The use of direct stenting has been a strong matter of debate in the medical community, and is mainly based on personal preference and experience. This study confirms what was shown in a subgroup analysis from the SIRIUS trial. In the present study, direct stenting was successful in a high percentage of patients and was associated with decreased procedural time and a trend toward a lower rate of intraprocedural complications. Of particular interest are the favorable findings among patients with diabetes, which is a subgroup of patients that did not have good outcomes in the SIRIUS study.
There is no doubt that there are some caveats to the way this study was performed, particularly when considering that the data for the control group were collected early on in the drug-eluting stent experience and improvements in technique and general familiarity with the devices may have accounted for some of the improved outcomes in this more recent trial. In addition, the stent-to-lesion length ratio was longer in the direct stenting arm than in patients treated with a predilatation strategy, and some have argued that larger ratios are associated with better outcomes. Nevertheless, the findings from the DIRECT trial are an important step in making stent implantation a simpler and safer procedure.
Reference
Moses JW, Leon MB, Popma JJ, et al. Sirolimus-eluting stents versus standard stents in patients with stenosis in a native coronary artery. N Engl J Med. 2003;349:1315-1323.