Author + information
- Received March 2, 1999
- Revision received June 21, 1999
- Accepted August 25, 1999
- Published online December 1, 1999.
- Carlo Briguori, MD†,
- Imad Sheiban, MD∗,* (, )
- Joseph De Gregorio, MD†,
- Angelo Anzuini, MD∗,
- Matteo Montorfano, MD∗,
- Paolo Pagnotta, MD∗,
- Federica Marsico, MD∗,
- Filippo Leonardo, MD∗,
- Carlo Di Mario, MD, PhD∗ and
- Antonio Colombo, MD, FACC†
- ↵*Reprint requests and correspondence: Dr. Imad Sheiban, San Raffaele Hospital, HRS, Via Olgettina, 60, I-20142, Milan, Italy
Coronary stenting is the primary therapeutic option for percutaneous treatment of many coronary lesions, after the risk of subacute stent thrombosis and bleeding complications has been reduced by improved antithrombotic regimens and high pressure stent expansion.
Direct stent implantation (without predilation) has been considered a promising new technique that may reduce the procedure time, radiation exposure time and cost.
After having reviewed all cases of stent implantation from February to June 1998 (n = 585), 185 (32%) of these patients were retrospectively considered candidates for direct stent implantation without predilation, according to prespecified criteria (i.e., absence of severe coronary calcifications and/or tortuosity of the lesion or the segment proximal to the lesion). By operator preference, direct coronary stent implantation was actually attempted in 123 (21%) of the 585 patients (100 men, 60 ± 10 years old) on 123 lesions. The impact of direct stenting in terms of cost, procedure time, radiation exposure time and amount of contrast dye used was assessed by comparing the two groups of patients who underwent single-vessel stenting without (n = 69) and with (n = 46) predilation.
Direct stenting was successful in 118 patients (96%). No acute or subacute complications occurred in these patients. Procedure time, radiation exposure time and cost were significantly lower in the group of patients who had single-vessel direct versus conventional stenting (45 ± 31 vs. 64 ± 46 min, 12 ± 9 vs. 16 ± 10 min and 1,305 ± 363 vs. 2,210 ± 803 Euro, respectively; p < 0.05 for all).
Direct stenting without predilation in selected lesions seems to be a safe and successful procedure that provides a way to contain cost and to shorten radiation exposure time.
Since the introduction of coronary stent implantation, interventional cardiologists have been using stents in ever increasing numbers (1). Improved long-term outcomes have contributed to the increase in stent usage, compared with balloon angioplasty, as demonstrated in two randomized trials (2,3). Moreover, the risk of subacute stent thrombosis and bleeding complications has been reduced by antithrombotic regimens and improved stent expansion (4). There are, however, several concerns related to this dramatic rise in the use of coronary stents—namely, the initial increase in cost to the patients and health care providers (5,6). In addition, in complex procedures there may be prolonged exposure time to radiation for both patients and operators, as well as an increase in the amount of contrast agent used (5).
The standard procedure recommended for stent implantation includes standard balloon angioplasty (predilation) followed by stent deployment. The availability of a low profile stent delivery system allows simplification of this procedure, avoiding the use of predilation. Direct coronary stenting without predilation may be helpful in reducing procedure time, cost and radiation exposure. To date, few reports exist about the feasibility and the potential advantages of direct coronary stenting (7–10). In the present study we analyzed: 1) the percentage of patients eligible for direct stenting in a single high volume center; 2) the feasibility of direct stenting using the common commercially available delivery system; 3) early results and complications of direct stenting; 4) the impact of direct stenting on cost, procedure time and radiation exposure time; and 5) the amount of contrast dye used.
From February to July 1998, 585 patients (806 lesions) underwent percutaneous transluminal coronary angioplasty (PTCA) with stent implantation in our institution. One-hundred eighty-five patients (32%) were considered “candidates” for direct stenting without predilation by two senior PTCA operators who independently reviewed the coronary angiograms. Agreement occurred in all patients but 10, for whom consensus was reached by consultation. Direct stenting was considered suitable in case of 1) vessel ≥2.5 mm in diameter; 2) absence of severe coronary calcifications; 3) absence of significant angulation (bend >45°); and 4) absence of occlusions and bifurcation lesions. One-hundred twenty-three (67%) of the 185 patients actually underwent direct stenting; these patients represent our total group of direct stenting. The remaining 62 patients (33%), although considered candidates for direct stenting, actually underwent traditional stent implantation with predilation because of operator preference.
Sixty-nine of the 123 patients underwent only single-vessel direct stenting, whereas the remaining 54 had multivessel coronary angioplasty (i.e., single-vessel direct stenting plus “conventional” coronary angioplasty and/or stenting on other[s] vessel[s]). This means that the 123 patients (total group) can be classified into the group with single-vessel disease traditionally best suitable for direct stenting (group 1) and into the group with multivessel disease who underwent direct stenting on one lesion and additional procedures on the others. The clinical characteristics of the total group (n = 123) who underwent direct stenting (total group) and of the subgroup who had only single-vessel direct stenting (group 1) are summarized in the Table 1. Table 2outlines the angiographic and procedural characteristics.
All patients received a low intraarterial bolus dose of unfractionated heparin (70 to 80 UI/kg). An Extra Back-up guiding catheter (Cordis, Miami, Florida) was generally used to cannulate the left anterior descending coronary artery and the left circumflex artery, and a right Judkins or left Amplatz catheter was used for the right coronary artery. After crossing the lesion with a soft guide wire, the stent was advanced over the guide wire and positioned properly. The passage of the stent to the desired position at the lesion site was attempted with moderate push, and if necessary (while possible and safe), with deep intubation of the guiding catheter. If this approach was not successful, the lesion was dilated with a standard low profile angioplasty balloon before stenting. After stent implantation, angiographic optimization was performed by using high pressure balloon dilation to achieve a good angiographic result with <20% residual stenosis by visual estimate. If the angiographic assessment of the lesion demonstrated incomplete expansion of the stent or presence of residual stenosis >20%, or both, a short balloon capable of high pressures was used for further inflation. Patients received intracoronary isosorbide dinitrate (1 to 3 mg) before the initial and final angiograms to achieve maximal vasodilation. The stents implanted with a direct technique without predilation included the NIR stent (46%) (SciMed, Boston Scientific, Maple Grove, Minnesota), the ACS Multi-Link Duet (36%) (Guidant Inc., Temecula, California), the AVE GFX (9%) (Applied Vascular Engineering Inc., Santa Rosa, California), the Palmaz-Schatz (1.5%) and the CrossFlex (6.5%) stents (Johnson & Johnson Interventional System Co, Warren, New Jersey) and the Crown stent (1%) (Cordis). In particular, the NIR stent was mounted on a Activa balloon (crossing profile 1.08 mm), and the ACS Multi-Link delivery system had a crossing profile of 1.19 mm.
In all patients, indications for stenting were elective, because the operator elected to use stenting before starting the procedure. Angiographic measurements were performed as previously described with an automated computer-based system by experienced angiographers not involved in the stenting procedure (4). A clinically significant lesion was defined as stenosis with at least ≥70% reduction of the reference vessel diameter as assessed visually. Lesions were characterized according to the modified American College of Cardiology/American Heart Association classification (11). Thrombus was defined as a filling defect seen in multiple projections surrounded by contrast medium. Left ventricular ejection fraction was measured by the ventricular angiogram with the area–length ellipsoid method. Any in-hospital major adverse cardiac event (MACE) (i.e., death, Q and non–Q wave myocardial infarction, coronary artery bypass graft surgery or PTCA) was assessed. Non–Q wave myocardial infarction was defined as chest pain or ST segment or T wave abnormalities, transient or sustained, associated with an increase of total creatine kinase two times or more above normal values without any new pathologic Q wave. Cardiac enzymes were measured in case of 1) transient or permanent vessel or side branch occlusion during the procedure; 2) prolonged (≥15 min) chest pain after a successful procedure; and 3) electrocardiographic changes with or without chest pain. Clinical follow-up was performed at 1 month by telephone contact to the patients or the referring physician.
Potential advantages of direct coronary stenting
To define the potential impact of direct coronary stenting on cost, procedure time, radiation exposure time and the amount of contrast media used, we compared the patients with single-vessel stenting who actually had direct stenting (group 1, n = 69) with the patients who were considered “candidates” (but not actually underwent) for direct stenting (group 2, n = 46). These comparisons excluded all patients with multivessel disease who were traditionally less suitable for direct stenting. The clinical, angiographic and procedural characteristics of the two groups are summarized in Tables 1 and 2. Cardiac catheterization laboratory utilization and costs were estimated as the costs of all supplies and personnel utilized in each procedure. Procedure cost, per se, was estimated by accounting for resource utilization, including angioplasty balloons, devices (i.e., stents) guiding catheters, guide wires and contrast dye (all recorded for each procedure). Balloons employed were calculated by considering the balloon of the stent delivery system as one. The cost of each item was determined by using actual manufacturer’s charges to the hospital during the financial year 1997. Cardiac catheterization laboratory costincluded additional equipment costs, laboratory room costs and personal costs, estimated on the basis of an average cost per procedure and adjusted for actual procedure duration. Cardiac catheterization laboratory cost in our institution was estimated ≈1,015 Euro/h during the financial year 1997. The total procedure cost (1 Euro = 0.93 U.S. dollar) was assessed as the sum of procedure cost, per se, and cardiac catheterization laboratory cost.
Continuous variables are given as the mean value ± SD. Probability values <0.05 were considered significant. The Student ttest and chi-square test were performed to compare continuous and categorical variables, respectively. Data were analyzed with SPSS for Windows 6.1.
Feasibility of direct stenting
Direct stent deployment without predilation was successfully performed in 118 patients (96%). In the remaining five patients (4%), the stent could be successfully withdrawn (without stent loss or damage), and after predilation the same stent was successfully deployed. A downward occlusive coronary dissection occurred in two patients; both were treated with prolonged balloon inflation and additional stenting. In no patient did stent loss or failed expansion of the stent during deployment occur. Primary success was therefore 94%; overall procedural success was 96%; and angiographic success was attained in all patients. There were no in-hospital deaths, myocardial infarctions or emergency bypass surgeries. During the first month of follow-up, no patients had subacute stent thrombosis or MACE.
Potential advantages of direct stent implantation
Tables 1 and 2outline the clinical, angiographic and procedural characteristics of patients who underwent single-vessel stenting without predilation (n = 69, group 1) and with predilation (n = 46, group 2). Hypertension and diabetes mellitus were more frequent in group 1. Direct stenting was successful in all 69 patients of group 1; thus, no additional stent and/or balloon was necessary (procedural success 100%). Angiographic success was achieved in all patients in the two groups. Residual stenosis and minimal lumen diameter after stent deployment was not statistically different between the two groups. Furthermore, no residual dissection was present in the two groups. The procedure cost, procedure time, radiation exposure time and amount of contrast dye used in the 69 patients with successful single-vessel direct stent deployment (direct stenting group) and in the 46 patients with “traditional” stenting with predilation are summarized in Table 3. Of note, all these variables were significantly lower in group 1. In particular, the average number of balloons used was 1.7 for traditional stenting and 1.0 for direct stenting (p < 0.001). No patients in the two groups experienced acute and subacute stent thrombosis or MACE one month after the procedure.
Coronary stenting has revolutionized the field of interventional cardiology, which previously relied on balloon dilation in the majority of patients. This rapid acceptance of coronary stenting has been due to two main factors. First, large randomized multicenter trials have shown that stenting has a lower restenosis rate and a better long-term clinical outcome than coronary balloon angioplasty in de novo or restenotic lesions (2,3). Furthermore, smaller nonrandomized studies have also demonstrated that stenting can improve primary and long-term success in lesions with high recurrence rates after balloon angioplasty, such as stenosis in vein bypass grafts, aorto-ostial stenosis and chronic total occlusion (2,3). Second, stent thrombosis, bleeding and vascular complication are no longer a major concern because of the improvements in deployment technique and in antiplatelet therapy (4,12). Elective coronary stenting became the most frequent indication for coronary stenting, followed by bailout stenting and stenting for an inadequate result (13). There are, however, several concerns related to this dramatic rise in the use of coronary stents—namely, the initial increase in cost to the patients and health care providers (5,6). In addition, in complex procedures there may be prolonged exposure time to radiation for both patients and operators, as well as an increase in the amount of contrast media used (6–14).
Direct coronary stenting
Direct coronary stenting without predilation may be helpful in reducing procedure times, costs and radiation exposure without increasing the risk to patients. Furthermore, in animal models, when a stent is placed without antecedent balloon denudation, sufficient endothelium remains within the stented segment to allow repopulation with a much reduced requirement for endothelial proliferation and migration (15). It is therefore hypothesized that if some endothelium is present in atherosclerotic vessels, a stent used without predilation may provide a means for dilating arteries while avoiding complete endothelial denudation (16). In the present study we found that direct stenting was considered suitable (by two independent invasive cardiologists) in 32% of patients who underwent coronary stent implantation. Although this is a retrospective analysis, and selection and observer-related biases should be taken into account, to our knowledge, this is the first study to quantitatively define the potential suitability of direct stenting.
The main finding that emerges from this single-center experience is that direct coronary stenting without predilation is a feasible and safe new therapeutic approach. In our experience, it was successful in 96% of the patients. Of note, complications occurred rarely; in fact, no patient had stent loss, whereas dissections after the initial stent deployment were observed in <2% of successful direct coronary stenting. Thus, the lack of predilation of the stenotic segment in direct coronary stenting does not seem to predispose to this complication, and may actually decrease its occurrence. Recently, Figulla et al. (7)reported a direct coronary stenting success rate of 80% by using a rapid exchange balloon catheter. In the present study we reported our experience of direct coronary stenting using some of the commonly available very low profile stents. In particular, we mostly used the NIR stent mounted on a Activa balloon catheter (crossing profile 1.08 mm) and the ACS Multi-Link Duet delivery system (crossing profile 1.19 mm) stent. Delivery system crossing profile ranged from 1.08 mm (NIR on Viva Primo) to 1.27 mm (AVE GFX II). The minimal lumen diameter of the target lesion was 0.9 ± 0.5 mm. The average percent stenosis was 77 ± 15%, in the same range as that reported by Figulla et al. (7).
Potential advantages of direct coronary stenting
Treatment costs for coronary stenting are significantly higher than those for conventional angioplasty (5,6). Consequently, several investigators have cautioned that widespread application of these procedures might have a deleterious impact on national health care expenditures, thus tempering the general level of enthusiasm for these technique (5,6). Although any evaluation of the cost-effectiveness of any therapeutic strategy must take into account both the costs and benefits of the treatment relative to its alternative, a favorable cost-benefit ratio would be met by coming close to the use of one stent and one balloon per patient. In this contest, one rational approach is the use of the same balloon for predilation and subsequent stent expansion.
According to Figulla et al. (7), in the present study we found that direct stenting without predilation significantly reduced procedure time and radiation exposure as compared with conventional stent implantation with predilation. In particular, procedure time was decreased by 30%, radiation exposure by 25%, contrast agent use by 28% and cost by 41%. Procedural variables such as radiation exposure time are difficult to compare among different institutions. In fact, Schatz et al. (17), who compared radiation exposure in different interventional techniques, gave exposure times for conventional balloon angioplasty and stenting between 24 and 29 min. Furthermore, Figulla et al. (7)reported a radiation exposure time of 8.7 ± 5.1 min in direct stenting and 12.6 ± 7.6 min in conventional stent implantation.
Other potential advantages of direct stenting without predilation might be represented by the reduction of ischemic time, which could be clinically relevant in specific patient subgroups (i.e., patients with severe left ventricular dysfunction and patients with left main coronary artery disease). In these patients, primary stenting might allow shortening of ischemic time and improving clinical outcome. Nevertheless, direct stenting might reduce the restenosis rate, as was pointed out in two experimental studies (15,16). Prospective randomized studies are currently used to confirm both the short-term and possibly long-term benefits of this approach.
The major limitation of the present study is that it is a nonrandomized study. The criteria for selecting patients suitable for primary stenting were subjective; therefore, an intrinsic bias is present. All of the 62 patients who were considered suitable for direct stenting actually underwent the “conventional” procedure because of operator preference. Direct stent implantation without predilation is more demanding than the conventional procedure, and more experience is required with the interventional decision strategy than with the conventional procedure. A potential limitation of the direct stenting approach is the occasional event of incomplete balloons and stent expansion in a calcified lesion, which could have been pretreated by rotational atherectomy. We did not encounter this problem because we excluded lesions with severe calcification and because our study group was quite small. Another limitation could be the smaller lumen cross-sectional area found in direct stenting as compared with traditional stenting owing to less aggressive predilation and postdilation. We cannot address this issue because of the fact that no intravascular ultrasound evaluation was systematically performed. From a conceptual point of view, it should be kept in mind that performance of direct stenting does not preclude evaluation of the final result by intravascular ultrasound and subsequent aggressive postdilation, if necessary.
In this study we found that direct stenting without predilation in selected lesions seems to be a safe and feasible procedure that provides a way to contain cost and shorten radiation exposure time. This approach may be performed using the commonly available stents and delivery systems. Other studies are needed to verify the impact of direct stenting on restenosis rates and long-term clinical outcomes.
- major adverse cardiac events
- percutaneous transluminal coronary angioplasty
- Received March 2, 1999.
- Revision received June 21, 1999.
- Accepted August 25, 1999.
- American College of Cardiology
- Fischman D,
- Leon M,
- Baim D,
- et al.
- Colombo A,
- Hall P,
- Nakamura S,
- et al.
- Cohen D.J,
- Breall J.A,
- Ho K.K.L,
- et al.
- Cohen D.J,
- Breall J.A,
- Ho K.K.L,
- et al.
- Chevalier B, Royer T, Glatt B, Guyon P, Straliev V. Is direct stent implantation feasible? Eur Heart J 1997;18 Suppl P2208:386.
- Bedossa M,
- LeBreton H,
- Commeau P,
- et al.
- Ryan T.J,
- Faxon D.P,
- Gunnar R.M,
- et al.
- Windeckers S,
- Meyer B.J,
- Bonzel T,
- et al.
- Ellis S.G,
- Miller D.P,
- Brown K.J,
- Omoigui F,
- Howell G.L
- Rogers C,
- Karnovsky M.J,
- Edelman E.R
- Fischell T.A,
- Derby G,
- Tse T.M,
- Stadius M.L
- Schatz R.A,
- Baim D.S,
- Leon M,
- et al.