Coronary artery stenting in unstable angina pectoris: a comparison with stable angina pectoris

OBJECTIVE: To compare early complication rates in unselected cases of coronary artery stenting in patients with stable v unstable angina. SETTING: Tertiary referral centre. PATIENTS: 390 patients with stable angina pectoris (SAP) and 306 with unstable angina (UAP). Patients treated for acute myocardial infarction (primary angioplasty) or cardiogenic shock were excluded. INTERVENTIONS: 268 coronary stents were attempted in 211 patients (30.3%). Stents used included AVE (63%), Freedom (14%), NIR (7%), Palmaz-Schatz (5%), JO (5%), and Multilink (4%). Intravascular ultrasound was not used in any of the cases. All stented patients were treated with ticlopidine and aspirin together with periprocedural unfractionated heparin. RESULTS: 123 stents were successfully deployed in 99 SAP patients v 132 stents in 103 UAP patients. Failed deployment occurred with nine stents in SAP patients, v four in UAP patients (NS). Stent thrombosis occurred in four SAP patients and 11 UAP patients. Multivariate analysis showed no relation between stent thrombosis and clinical presentation (SAP v UAP), age, sex, target vessel, stent length, or make of stent. Stent thrombosis was associated with small vessel size (p < 0.001) and bailout stenting (p = 0.01) compared with elective stenting and stenting for suboptimal PTCA, with strong trends toward smaller stent diameter (p = 0.052) and number of stents deployed (p = 0.06). Most stent thromboses occurred in vessels < 3 mm diameter. CONCLUSIONS: Coronary artery stenting in unstable angina is safe in vessels >/= 3 mm diameter, with comparable initial success and stent thrombosis rates to stenting in stable angina.     

Early and late outcome of stenting in a consecutive series of patients with coronary lesions in vessels less than 2.8 mm in diameter

In an attempt to determine the early and late outcomes of small vessel stenting, we retrospectively evaluated our database on 51 consecutive patients (41 males, mean age, 57.1 +/- 10.1 years) who underwent stenting of at least one significant lesion in a coronary artery with a reference vessel diameter (RVD) <2.8 mm between March 1999 and March 2001. Sixty balloon expandable tubular stents were implanted in 57 lesions (29 Type B2/C, mean RVD: 2.54 +/- 0.16 mm) without intravascular ultrasound guidance under a heparin-aspirin-ticlopidine regimen. The mean diameter stenosis (DS) decreased from 75.8 +/- 13.6% to 4.2 +/- 1.9% (P<0.0001) with stenting at a mean deployment pressure of 13.6 +/- 1.7 atm and a final balloon to RVD ratio (FB/RVD) of 1.08 +/- 0.03. All stents were deployed successfully. Acute stent thrombosis occurred in 3 patients (6%), one died, and 2 developed non-Q-wave myocardial infarction (procedural success 94%). Clinical follow-up, available in 48 patients, revealed a 29% target lesion revascularization rate, a 2% myocardial infarction rate, and a 71% event-free survival at a mean of 11.6 months. Angiographic follow-up, available in 40 patients, showed a DS of 48.8 +/- 31.3% and a binary restenosis rate of 50% at a mean of 7.7 months. The FB/RVD ratio was significantly lower in the group with restenosis than in the group without (1.06 +/- 0.02 vs 1.1 +/- 0.05, P = 0.04). Subgroup analysis yielded a significantly greater rate of restenosis in diabetics with complex (Type B2/C) lesion morphology compared to nondiabetics with simple (Type A/B1) lesions (75% vs 21%, P < 0.05). In conclusion, stenting in vessels <2.8 mm was found to be associated with a high rate of acute stent thrombosis and in-stent restenosis. Further analysis detected a subgroup of patients without diabetes or complex lesions who could be stented with an acceptable in-stent restenosis rate.     

Is adjunctive balloon postdilatation necessary after coronary stent deployment? Final results from the POSTIT trial

Early-generation balloon-expandable stents required postdilatation with noncompliant balloons at high pressure to optimize stent deployment. The need for adjunctive balloon postdilatation with modern stent delivery systems is unknown. Patients undergoing elective stenting were randomized to Boston Scientific NIR, Guidant Tri-Star/Tetra, and Medtronic AVE S670 stents. The primary endpoint was optimum stent deployment defined as a minimal stent diameter (MSD) >/= 90% of the average reference lumen diameter assessed by intravascular ultrasound (IVUS) performed immediately following stent deployment. If, by operator assessment, the primary endpoint was not achieved with the stent delivery system, adjunctive postdilatation with noncompliant balloons was performed. Of 256 patients with IVUS studies adequate for core laboratory analysis, only 29% achieved optimum stent deployment with the stent delivery system. None of the baseline clinical or angiographic variables predicted optimum stent deployment. Of the procedural variables, the type of stent and nominal stent size were not predictors, but higher deployment pressures were associated with a higher frequency of optimum stent deployment (< 12 atm 14% vs. >/= 12 atm 36%; P = 0.007). The inability to achieve optimum stent deployment was not due to undersizing the stent delivery balloon, but rather to an inability of the stent delivery balloon to expand fully the stent to nominal size. In patients who underwent postdilatation, the frequency of achieving optimum stent deployment increased from 21% to 42%, minimal stent area increased from 6.6 +/- 2.2 to 7.8 +/- 2.3 mm(2), and MSD increased from 2.6 +/- 0.5 to 2.8 +/- 0.4 mm. These data stress the continued need for adjunctive balloon postdilatation with modern stent delivery systems. Cathet Cardiovasc Intervent 2003;59:184-192.     

Coronary stent implantation without lesion predilatation (direct stenting): our experience with this evolving technique

BACKGROUND: Until recently, conventional intracoronary stent deployment required predilatation of the lesion with a balloon. However, "direct stenting" of the lesion without predilatation offers certain theoretical and practical advantages. We assessed the safety and feasibility of direct stenting in a select group of patients who were likely to benefit most from these advantages, namely, those with acute coronary syndromes. saphenous vein graft lesions, associated renal or left ventricular dysfunction and those requiring multivessel intervention. METHODS AND RESULTS: After direct stenting, intravascular ultrasound was used to assess the adequacy of stent expansion in 51 patients. One hundred and twenty patients with a total of 125 lesions (83.3% males, average age 54.6+/-12.4 years) were enrolled for direct stenting. Of these, 90% of patients had presented with acute coronary syndromes, 21.6% of patients had associated moderate-to-severe left ventricular systolic dysfunction, 6.7% of patients had associated renal dysfunction and 30.8% of patients required multivessel intervention. Angiographically visible thrombus was present in 35.2% of patients. The mean reference diameter of the lesion was 3.18+/-0.32 mm and mean percentage diameter stenosis was 76.4+/-11.2%. Almost all varieties of stents were used (8.8% bare and 91.2% mounted). Procedural success was achieved in 98.3% of patients (98.4% of lesions). In two cases, the lesion had to be predilated prior to stenting. On angiography, the need for postdilatation of the stent was apparent in 29 (23.6%) lesions. In contrast, on intravascular ultrasound evaluation done in 51 lesions after stent deployment, the need for postdilatation to optimize stent expansion was seen in 43 (84.3%) lesions. There was one instance of acute stent thrombosis and two instances of slow-flow phenomenon. There were no deaths, myocardial infarction or need for urgent bypass surgery. CONCLUSIONS: We conclude that direct stenting is feasible and safe in selected groups of patients. Optimization of stent expansion after direct stenting may often require aggressive postdilatation.     

Comparison of the self-expanding Radius stent and the balloon-expandable Multilink stent for elective treatment of coronary stenoses: a serial analysis by intravascular ultrasound.

We compared the outcome of the self-expanding Radius stent and the balloon-expandable Multilink stent serially by angiography and intravascular ultrasound. Successful stent deployment was achieved in 66 lesions of 56 stable angina patients (34 lesions with Radius stents and 32 lesions with Multilink stents). At follow-up, there were no significant differences in minimal lumen diameter or percent diameter stenosis between the groups, nor in restenosis rates, although the Radius stent group rate was slightly lower (23.5% vs. 31.3%). In the Radius stent group, stent cross-sectional area (CSA) increased gradually after implantation until the 6-month follow-up (8.37 +/- 1.83 to 10.16 +/- 2.59 mm(2); n = 15), giving a larger CSA (P = 0.03) than the Multilink stent group, which decreased (9.00 +/- 2.05 to 8.27 +/- 2.15 mm(2); n = 17). The lumen CSA was also slightly larger (6.82 +/- 3.06 vs. 5.84 +/- 1.85 mm(2); P = 0.29) in the Radius stent group. These findings indicated that the Radius stent enlarged progressively after implantation, which might be useful for prevention of restenosis.     

Intracoronary stenting using slotted tubular stents without intravascular ultrasound and anticoagulation

Intravascular ultrasound guidance has been suggested as a prerequisite before managing patients receiving slotted tubular stents without anticoagulation. The purpose of this prospective observational study was to determine if patients receiving this stent can be similarly managed following angiographic guided stent deployment without intravascular ultrasound assistance. A total of 137 patients receiving slotted tubular stents were selected to receive a protocol of aspirin 325 mg and ticlopidine 250 mg for 30 days following the satisfactions of certain angiographic criteria. These criteria were: adequate coverage of intimal dissections, absence of residual filling defects, and normal (TIMI III) flow in the stented vessel at the end of the procedure. The stenting procedure was planned in 68% of patients and unplanned in 32% of patients. During the 30 day clinical follow period there were no stent thrombosis events, no Q-wave myocardial infarctions, and no deaths. Non-Q-wave myocardial Infarction occurred in 3 patients (2.2%), hemorrhage requiring blood transfusion in 3 patients (2.2%), and 1 patient (0.7%) developed a pseudo-aneurysm of the cannulated femoral artery. These data indicate that patients receiving slotted tubular stents with optimal angiographic results can be safely managed with the combination of aspirin and ticlopidine without anticoagulation or the need for intravascular ultrasound guidance. © 1996 Wiley-Liss, Inc.     

Multi-Link Stenting in Acute Myocardial Infarction

ACS Multi-Linka stent is a stainless steel balloon expandable stents composed of 12 rings connected by multiple links giving a great flexibility and radial strength. Multi-Link stenting offers good clinical and angiographic results in patients with unstable and stable angina, but there are few reports about Multi-Link stent placement in acute myocardial infarction (AMI). In this study, the experience of Multi-Link stenting during primary PTCA is described. RESULTS: 38 Multi-Link stents were placed in the culprit vessel in 34 patients with AMI. Mean age was 67 +/- 14 years, 25 (74%) were male, 12 (35%) were in Killip class III or IV and 20 (59%) had multi-vessel disease. All 38 Multi-Link stents (100%) could be successfully delivered. Angiographic success was achieved in 32 patients (94%). After stenting, stenosis decreased from 95 +/- 9% to 9 +/- 5% (p < 0.001) and minimal lumen diameter increased from 0.2 +/- 0.5 to 2.9 +/- 0.5 mm (p < 0.001). One patient (3%) suffered a subacute thrombosis requiring a new PTCA, but no patient needed surgical revascularization. Seven patients (20.6%; 95% CI: 8.7D37.9%) died during hospitalization, 6 of whom were in cardiogenic shock at admission. Mortality in patients with and without cardiogenic shock at admission was 85.7% (95% CI: 42.1D99.6%) and 3.7% (95% CI: 0.1%D20.0%) respectively (p < 0.001). CONCLUSION: The Multi-Link stent offers good angiographic results in patients with AMI. The in-hospital mortality in patients without cardiogenic shock at admission is low.     

Palmaz-Schatz Coronary Stent Implantation Without Intravascular Ultrasound and Without Subsequent Anticoagulation: Clinical Outcome

OBJECTIVES: To determine the safety and efficacy of antiplatelet therapy alone in a selected group of patients following coronary stenting. BACKGROUND: Coronary stent implantation is an effective treatment for abrupt closure, and can also reduce the restenosis rate following percutaneous transluminal coronary angioplasty. However, anticoagulation therapy following stent implantation is associated with a significant incidence of vascular complications and subacute stent thrombosis. METHODS: Between February and November 1994 we implanted 62 Palmaz-Schatz stents in 50 patients with an optimal angiographic result following stent deployment. In these patients, intravascular ultrasound was not used, and a regimen of aspirin 100 mg daily indefinitely and ticlopidine 250 mg twice daily for 3 months was started without anticoagulation. RESULTS: Of these 50 patients (10 females : 40 males, mean age 63 +/- 12 years, LVEF 64 +/- 10%), 39 (78%) were stented for a suboptimal angiographic result post angioplasty, 2 (4%) received stents as a bailout procedure, and 9 (18%) were stented electively. Average hospital stay following stent implantation was 3.7 +/- 3.0 days. After a mean follow-up period of 140 +/- 70 days, there were no instances of stent occlusion, death, stroke, need for coronary bypass surgery, Q-wave myocardial infarction or femoral artery pseudoaneurysm. There was 1 case (2%) of significant puncture site hemorrhage. CONCLUSIONS: Immediate angiographic appearance after stent implantation can be used to define patients at low risk of stent thrombosis who do not require anticoagulation and can safely be discharged early from the hospital.     

Standardized angiographically guided over-dilatation of stents using high pressure technique optimize results without increasing risks

BACKGROUND: Routine angio-guided stent deployment results in a relatively high restenosis rate, which is mostly due to stent sub-expansion. Several different intravascular ultrasound (IVUS) criteria for optimal stent deployment have been proposed. A minimal in-stent restenosis and a minimal in-stent lumen area of > or = 9 mm2 have been associated with low rates of restenosis and target lesion revascularization (TLR) at 6 months. The role of high-pressure stent deployment and/or upsizing the post-dilatation balloon has not yet been clarified. The aim of this study was to evaluate the possibility of achieving accepted IVUS criteria safely without IVUS guidance with the combination of high-pressure deployment and post-dilatation with a 0.25 mm oversized balloon. METHODS: Thirty-four stents (26 NIR, 3 AVE GFX, 3 ACS GFX, 1 Bard, 1 Jostent) were implanted in 30 patients until optimal angiographical results were obtained (< 10% residual stenosis visually). Forty percent of the patients had unstable angina pectoris, forty-four percent had complex lesions (B2 and C) and 29% were occlusions. Mean inflation pressure was 12.6 +/- 1.6 atm, mean stent diameter was 3.2+/- 0.4 mm and mean stent length was 15.1+/- 5.4 mm. Post-dilatation was performed with the same stent using a short (compared to the angiographic reference segment), 0.25 mm oversized Scimed Maxxum Energy 3.5 +/- 0.4 mm balloon using high pressure (16.1 +/- 1.7 atm) followed by an off-line IVUS examination of the stents. There was clinical follow-up for 1 year. Results in patients with single-vessel disease were compared with those of non-randomized controls, who were stented with high pressure but without over-dilatation. RESULTS: No stent achieved the nominal diameter, in spite of over-dilatation. Mean minimal stent diameter (MLD) according to IVUS was 2.9 +/- 0.4 mm (92% of the angiographic reference diameter). Mean minimal lumen area (MLA) was 7.7 +/- 2.2 mm2. An in-stent MLA > or = 90% of the distal reference segment (AVID criteria) and an MLA > or = 100% or > or = 90% of the smallest/average reference segment (MUSIC criteria) was found in 67% and 57%, respectively. MLA > or = 9 mm2 was achieved in 38%. All stents had good apposition and obtained a symmetry index > or = 0.7 mm. No acute perforations, dissections or other serious complications occurred during the over-dilatation. At 1 year, five patients had re-angina leading to a new coronary angiography; only 1 patient had a significant in-stent restenosis requiring re-PTCA. Compared to non-overdilated historical controls, the standardized over-dilatation seemed to give a larger MLD (3.0 +/- 0.4 mm vs. 2.7 +/- 0.4 mm; p = 0.03), more patients who fulfilled AVID criteria (70% vs. 32%; p = 0.048) and more stents with MLA > or = 9 mm2 (46% vs. 11%; p = 0.02). CONCLUSION: A standardized 0.25 mm over-dilatation of stents never achieved nominal stent size, but did improve lumen gain and was associated with low target vessel revascularization without adding complications to the routine stenting procedure.     

Stenting for in-stent restenosis.

Intravascular ultrasound studies have shown that additional stent implantation is the only percutaneous technique that allows for recovery of all the lumen area of the original implantation procedure. Despite this theoretical advantage, information on systematic additional stent implantation is still forthcoming, especially concerning the impact of new stent designs. This prospective study evaluated the efficacy of routine additional stent implantation for treatment of in-stent restenosis in 68 consecutive patients. Repeat stenting was successful in all cases, and second-generation tubular stents were used in 84% of patients. The mean additional stent length was 19.2 +/- 9.4 mm, and 15% of patients had multiple stent implantation. The postprocedure minimum lumen diameter was 3.11 +/- 0.41 mm, and the percentage residual stenosis was 2% +/- 7%. At a mean clinical follow-up of 10 +/- 8 months (follow-up rate 100%), the incidence of major adverse events was 21% (1 death, 13 target vessel revascularizations). Overall, angiographic restenosis rate was 32% (angiographic follow-up rate 79%). By multivariate analysis, the only predictors of recurrence after additional stenting were unstable angina at the second procedure (OR 8.70, 95% CI 1.50-50.33, P = 0.019), and early clinical recurrence after the first stent procedure (OR 4.83, 95% CI 1.13-20.71, P = 0.038). Additional stenting is a safe and effective treatment modality for the majority of patients with in-stent restenosis. Alternative treatments should be considered only for patients with in-stent restenosis presenting as unstable angina or early recurrence after a first stent procedure.     

Comparison of coronary stent expansion by intravascular ultrasonic imaging in younger versus older patients with diabetes mellitus

The poor long-term outcome in young diabetic patients receiving stents is not well understood. The purpose of this study was to characterize the pastprocedural results of stent placement in diabetic patients using intravascular ultrasound to identify factors that might be associated with poor clinical outcome. The acute dimensions from intravascular ultrasound studies after stent deployment at 5 sites were measured from 39 coronary segments from patients with diabetes mellitus (DM) and 161 segments from nondiabetic patients (non-DM). Within these 2 groups, segments were subgrouped into young (y) and old (o) in reference to the mean study age of 64 years, forming 4 groups: yDM (n = 20), y non-DM (n = 65), oDM (n = 19), and o non-DM (n = 96). Results are reported as mean +/- 1 SD. Diabetic patients had smaller mean lumen area within the treated segment than o non-DM (8.37+/-2.59 vs. 9.11+/-3.35 mm2, p<0.01). These differences were more pronounced at the distal reference vessel lumen of yDM than y non-DM (7.6+/-2.3 vs. 10.3+/-4.5 mm2, p<0.003), and were associated with greater percent plaque area in the distal reference vessel (43.4+/-13% vs. 34.1+/-11.2%, p<0.003). In young diabetic patients undergoing elective stent placement, underexpansion of the stented segment is common, which may contribute to the relatively poor long-term outcome in these patients. We suggest that when stenting is the procedure of choice in this subgroup of high-risk patients, special attention should be given to optimizing lumen dimensions.     

Subacute stent thrombosis following coronary angioplasty: incidence and risk factors

BACKGROUND: Subacute stent thrombosis was a significant complication in the early years of coronary stenting, often leading to myocardial infarction, need for urgent surgery or even death. The introduction of intracoronary ultrasound enabled the identification and proper treatment of the main causes of stent thrombosis, reducing the rate of this complication to 1%. AIM: To identify risk factors of subacute stent thrombosis. METHODS: Data concerning 845 procedures with a single stent implantation in patients with stable or unstable angina, undergoing this procedure between 1998 and 2000, were analysed. RESULTS: Subacute stent thrombosis occurred in 13 (1.54%) patients. Risk factors for this complication included urgent procedures (so-called bailout stenting), improper pre-treatment with drugs ("ad hoc" procedures), dissection uncovered by stent, and poor final result of procedure (higher degree of residual stenosis). The majority of these patients developed myocardial infarction in spite of the fact that the patency of stented vessel was quickly achieved in all but one patient. CONCLUSIONS: Urgent stenting, improper drug pre-treatment and suboptimal result of the procedure are the risk factors of subacute stent thrombosis.     

Direct coronary stent implantation: safety, feasibility, and predictors of success of the strategy of direct coronary stent implantation.

This prospective study was designed to evaluate the feasibility, safety, predictive factors of success, and 6-month follow-up of stent implantation without balloon predilatation (direct stenting) in 250 patients undergoing elective stent implantation. Balloon dilatation prior to stent implantation was a prerequisite to facilitate passage and deployment of the stent. Stent technology has changed tremendously, resulting in stents with improved properties, which may allow stent placement without prior balloon dilatation. Patients with coronary lesions suitable for elective stent implantation were included in this trial. Coronary interventions were undertaken predominantly via the transradial route using 6 Fr guiding catheters. Direct stent implantation was attempted using AVE GFX II coronary stent delivery systems. Upon failure, predilatation was undertaken before reattempting stent implantation. Patient data and ECGs were obtained from case records and from personal or telephone interviews 6 months after the procedure. Values were presented as mean +/- standard deviation. Student's t-test, two-tailed at 5% level of significance, was used to compare the difference of two means. Multivariate logistic regression analysis was performed to establish predictive factors for failure of direct stenting. Two hundred and sixty-six direct stent implantations were attempted in 250 patients. Direct stenting was successful in 226 (85%) cases. Out of 40(15%) cases where direct stenting failed, balloon predilatation facilitated stent implantation in 39. In one lesion, stent implantation was not possible despite adequate predilatation. Predictive factors for failure of direct stenting on multivariate analysis were LCx lesions (P < 0.01), complex lesions (P < 0.01), and longer stents (P < 0.001). Minimal luminal diameter and percentage diameter stenosis of lesions in the successful and the failure group were not significantly different (0.94 +/- 0.39 mm vs. 0.84 +/- 0.41 mm, P = NS, and 70.2 +/- 11.2 vs. 73.2 +/- 11.2, P = NS). Stent loss occurred in five (2.0%) cases, with successful retrieval in four. One stent was lost permanently in a small branch of the radial artery. Post-percutaneous coronary intervention (post-PCI) myocardial infarction occurred in four (1.6%) patients. There were no other in-hospital events. Six-month-follow up information was obtained in 99% of patients. Subacute stent thrombosis was noted in four (1.6%) cases. Target vessel-related myocardial infarction rate was 3.2%, of which half was caused by subacute stent thrombosis. The overall reintervention rate (coronary artery bypass grafting or PCI) was 9.7%. Target lesion revascularization by PCI occurred in only 4.0%. At 6 months, overall mortality was 2.0%, of which 1.2% was due to coronary events. Direct stent implantation is safe and feasible in the majority of cases with low rate of complications. Unfavorable factors include circumflex lesion, more complex lesion morphology, and increasing length of stent. Severity of stenosis does not appear to be of predictive value. Long-term outcome is favorable with a low target lesion revascularization rate.     

Initial experience with a newer generation coronary stent

BACKGROUND: Recently, several newer generation stents have become available promising to improve upon the results of coronary angioplasty (PTCA) with its attendant acute and chronic complications. The aim of this study was to prospectively review the results of a preliminary experience with the newer generation R stent in a series of 56 patients. METHODS: This study included 47 men and 9 women, aged 57 +/- 10 years, who presented with stable angina and/or positive exercise testing (n = 12), unstable angina (n = 42), or acute myocardial infarction (n = 2). A consistent approach by a single operator for implantation of the R stent (Orbus Inc., The Netherlands) included stent oversizing (by 0.5 mm) and high pressure (> 12--16 bar) deployment. Dilated vessels comprised the left anterior descending (n = 37) including the diagonal branch in 2 patients, the right coronary artery (n = 17), the left circumflex (n = 13), or a saphenous vein graft (n = 1). The mean left ventricular ejection fraction was 52 +/- 8% and the initial coronary artery stenosis was 85 +/- 8%. Stents were implanted for dissection and/or suboptimal PTCA result or electively. RESULTS: The procedure was successful in all 56 patients (100%). The residual stenosis was < 0--10%. Direct stenting without balloon predilation was performed in 21 patients. Single stents were used in 36 patients and > or = 2 stents in 20 patients. Abciximab (n = 22), eptifibatide (n = 8) or tirofiban (n = 1) was administered in 31 patients (55%). A stent-related complication was noted in one patient (stent misplacement). All patients were discharged alive without infarct or need for surgery. There were no events of subacute stent thrombosis; all patients received combined therapy with aspirin and clopidogrel, the latter for 1 month. In one patient who had received abciximab, severe thrombocytopenia (0 platelet count) was detected at 3 days after discharge but it was fully reversible with no sequelae. Over 5.2 +/- 2.8 (range, 1--11) months, there was one sudden death and two clinical restenoses; no other late complication occurred. CONCLUSION: Initial experience with 73 R stents in 56 patients and a consistent approach by a single operator of stent oversizing and high-pressure deployment resulted in high procedural success (100%), lack of stent thrombosis (0%), and a low stent-related complication rate (1.8%), while the design and profile of the R stent allowed for direct stenting in 37.5% of patients. One should be vigilant for the sporadic occurrence of severe thrombocytopenia with use of IIb/IIIa inhibitors.     

First International New Intravascular Rigid-Flex Endovascular Stent Study (FINESS): Clinical and Angiographic Results After Elective and Urgent Stent Implantation

Objectives. The purpose of this study was to determine the feasibility, safety and efficacy of elective and urgent deployment of the new intravascular rigid-flex (NIR) stent in patients with coronary artery disease.Background. Stent implantation has been shown to be effective in the treatment of focal, new coronary stenoses and in restoring coronary flow after coronary dissection and abrupt vessel closure. However, currently available stents either lack flexibility, hindering navigation through tortuous arteries, or lack axial strength, resulting in suboptimal scaffolding of the vessel. The unique transforming multicellular design of the NIR stent appears to provide both longitudinal flexibility and radial strength.Methods. NIR stent implantation was attempted in 255 patients (341 lesions) enrolled prospectively in a multicenter international registry from December 1995 through March 1996. Nine-, 16- and 32-mm long NIR stents were manually crimped onto coronary balloons and deployed in native coronary (94%) and saphenous vein graft (6%) lesions. Seventy-four percent of patients underwent elective stenting for primary or restenotic lesions, 21% for a suboptimal angioplasty result and 5% for threatened or abrupt vessel closure. Fifty-two percent of patients presented with unstable angina, 48% had a previous myocardial infarction, and 45% had multivessel disease. Coronary lesions were frequently complex, occurring in relatively small arteries (mean [±SD] reference diameter 2.8 ± 0.6 mm). Patients were followed up for 6 months for the occurrence of major adverse cardiovascular events.Results. Stent deployment was accomplished in 98% of lesions. Mean minimal lumen diameter increased by 1.51 ± 0.51 mm (from 1.09 ± 0.43 mm before to 2.60 ± 0.50 mm after the procedure). Mean percent diameter stenosis decreased from 61 ± 13% before to 17 ± 7% after intervention. A successful interventional procedure with <50% diameter stenosis of all treatment site lesions and no major adverse cardiac events within 30 days occurred in 95% of patients. Event-free survival at 6 months was 82%. Ninety-four percent of surviving patients were either asymptomatic or had mild stable angina at 6 month follow-up.Conclusions. Despite unfavorable clinical and angiographic characteristics of the majority of patients enrolled, the acute angiographic results and early clinical outcome after NIR stent deployment were very promising. A prospective, randomized trial comparing the NIR stent with other currently available stents appears warranted.     

Coronary stenting without pre-dilatation: an observational study

Conventional coronary stenting is done after pre-dilatation of the lesion. The bleeding complications and incidence of subacute stent thrombosis have been reduced significantly by the use of antiplatelet agents and high pressure balloon inflation to ensure complete stent expansion. Elective stenting also can be done without pre-dilatation by "stent alone technique." This approach significantly reduces the procedural cost and ischaemia time, avoiding potential complications such as abrupt vessel closure because of extensive dissection after conventional angioplasty and prior to stent deployment. Eighty patients of stable angina pectoris suitable for coronary angioplasty underwent stenting without pre-dilatation. Out of the 100 stents used, 38 were hand-crimped and 62 were pre-mounted. The target vessels were left anterior descending artery in 56 percent, right coronary artery in 32 percent and left circumflex in 12 percent. The procedure was successful in 88 percent lesions. In 12 percent stenting could be done only after pre-dilatation. In all these, there was proximal tortuosity and calcification. The fluoroscopy time was 10.2 +/- 4.5 minutes. The average number of balloons used per lesion was 1.08. Stent embolisation occurred in only one patient. There were no major adverse cardiac events in any of the patients. Thus stenting without pre-dilatation is safe. Patients who are eligible for stenting without pre-dilatation are those with stable angina pectoris without fluoroscopically visible calcium or coronary artery tortuosity and with lesions of moderate complexity.     

Expansion of the Multilink-Tristar stent after direct implantation and predilatation: comparison of clinical,angiography and intravascular ultrasound parameters

Coronary stenting has become the primary therapeutic option for many coronary lesions. As opposed to conventional stenting the advantages of direct stenting are a reduction of procedural time, radiation exposure and costs. However, data about the incidence of in-stent restenosis are so far not available. It was the aim of this prospective study to compare the expansion of the Multilink stent after direct stenting and predilatation by quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS). Between January 2000 and June 2001, 82 patients were assigned to direct stenting (46 lesions) or predilatation (40 lesions) in lesions of coronary arteries > 3 mm. The procedural success rate was 92% in patients undergoing direct stenting. The baseline clinical characteristics were similar in both groups. The comparison of the angiographic data shows that direct stenting was performed in lesions with a lower degree of stenosis (71 +/- 12% vs 79 +/- 11%, p = 0.01) and that significantly shorter stents were used (14.4 +/- 3.0 vs 17.8 +/- 4.1 mm, p = 0.0007). The mean stenosis length was not significantly different in either group (10.5 +/- 3.4 vs 11.7 +/- 4.3 mm, n.s.). The QCA data after stent implantation show no differences of either implantation technique. Stent expansion was assessed by IVUS estimation of the proximal, distal and minimal in stent area. The minimal in-stent area (9.53 +/- 3.23, mm2 vs 8.65 +/- 1.96 mm2, n.s.) and the stent symmetry index (0.88 vs 0.88 n.s.) were not different in either patient group. These results indicate that in this subset of selected coronary lesions > 3 mm, elective stent implantation with and without predilatation effectively can achieve comparable stent expansion as assessed by QCA and IVUS. In comparison to conventional stent implantation stents, which were implanted without predilatation, were significantly shorter to cover the same lesion length.     

Focal in-stent restenosis and in-stent thrombosis within the same bare-metal stent 5 years after deployment in a saphenous vein graft

Complications of percutaneous coronary intervention include in-stent restenosis (ISR) and in-stent thrombosis (IST) which have different underlying pathophysiological processes and different treatment strategies. ISR is primarily due to excessive neointimal growth and occurs in 20-30% of bare-metal stents (BMS). Drug-eluting stents (DES) have decreased the rates of ISR (< 10%), but are potentially associated with increased IST related to delayed arterial healing and stent strut exposure. ISR of BMS typically occurs within 6 months of stent deployment. IST usually occurs within 12 months of DES deployment. We present a case of focal ISR and IST within the same BMS, confirmed with intravascular ultrasound, 5 years after deployment in a saphenous vein graft.     

Efficacy and safety of direct stenting in coronary angioplasty

BACKGROUND: Direct stenting is the deployment of an intracoronary stent without lesion predilation. Potential advantages include shorter procedural time, lower contrast dose and reduced spiral dissections. There is also the potential financial benefit of less balloon and/or stent usage. Concern still exists among some operators, however, regarding failure of stent deployment and local complications. METHODS: Of 467 consecutive angioplasty cases at the Alfred Hospital between August 1, 1997 and May 22, 1998, direct stenting was attempted in 93 patients (20%). Interventionalist preference determined whether direct stenting was attempted. Vessels with excessive calcification, severe proximal tortuosity or small caliber were typically considered unsuitable for direct stenting. RESULTS: A total of 102 lesions (38 type A, 60 type B, and 4 type C) were treated with direct stenting. Initial deployment was successful in 98 of 102 lesions, with a further 3 lesions successfully stented following predilation. A stent was unable to be deployed in only 1 case; however, the lesion was treated with balloon angioplasty alone. The majority of lesions required only 1 stent (an average of 1.1 stents were used per lesion). Distal complications occurred in 5 patients. In 3 patients, a small distal dissection was successfully stented, and in 1 case embolization of debris occurred down the distal vessel, resulting in a small procedural myocardial infarction. Only 1 patient out of 93 (1%) developed a large distal dissection requiring the deployment of multiple stents, compared with 22 of the remaining 374 patients (5.9%) who underwent conventional angioplasty. This was a significant difference in favor of direct stenting (Chi-square, p < 0.05). When compared with a cohort of patients matched by lesion grade treated with conventional stenting, direct stenting used significantly less contrast per case (154 +/- 7.6 ml compared with 202 +/- 9.5 ml for conventional stenting; p = 0.0001). CONCLUSION: Direct stenting is a safe and effective method for treating coronary artery disease. In appropriately selected cases, it has a low rate of procedural failure and results in less contrast usage and fewer distal complications than conventional angioplasty and stenting.     

Lack of neointimal proliferation after implantation of sirolimus-coated stents in human coronary arteries: a quantitative coronary angiography and three-dimensional intravascular ultrasound study

BACKGROUND: Restenosis remains an important limitation of interventional cardiology. Therefore, we aimed to determine the safety and efficacy of sirolimus (a cell-cycle inhibitor)-coated BX Velocity stents. METHODS AND RESULTS: Thirty patients with angina pectoris were electively treated with 2 different formulations of sirolimus-coated stents (slow release [SR], n=15, and fast release [FR], n=15). All stents were successfully delivered, and patients were discharged without clinical complications. Independent core laboratories analyzed angiographic and 3D volumetric intravascular ultrasound data (immediately after procedure and at 4-month follow-up). Eight-month clinical follow-up was obtained for all patients. There was minimal neointimal hyperplasia in both groups (11.0+/-3.0% in the SR group and 10.4+/-3.0% in the FR group, P:=NS) by ultrasound and quantitative coronary angiography (in-stent late loss, 0.09+/-0.3 mm [SR] and -0.02+/-0.3 mm [FR]; in-lesion late loss, 0.16+/-0.3 mm [SR] and -0.1+/-0.3 mm [FR]). No in-stent or edge restenosis (diameter stenosis >or=50%) was observed. No major clinical events (stent thrombosis, repeat revascularization, myocardial infarction, or death) had occurred by 8 months. CONCLUSIONS: The implantation of sirolimus-coated BX Velocity stents is feasible and safe and elicits minimal neointimal proliferation. Additional placebo-controlled trials are required to confirm these promising results.