Clinical impact and evolution of mitral regurgitation after TAVI using the new generation self-expandable valves.

BACKGROUND: Concomitant mitral regurgitation (MR) impaired prognosis in patients undergoing transcatheter aortic valve implantation (TAVI). It has been suggested that the use of first generation self-expandable valve in patients with significant MR is associated with worse outcome as compared with balloon expandable valve. However, the impact of newer generation transcatheter devices on MR has not been investigated so far. We aim to assess the prognostic impact of MR in patients undergoing TAVI with the first-generation vs. the latest generation of self-expandable valves. METHODS: We analyzed 2964 consecutive patients who underwent TAVI. Patients were classified into 4 groups according to the degree of baseline MR and the generation of self expandable valve implanted. RESULTS: Of 1234 patients with moderate or severe MR, 817 were treated with first generation and 417 patients with second generation valves. Whereas, of 1730 patients with no or mild MR, 1130 were treated with first generation and 600 patients with second generation valves. Although, concomitant moderate-severe MR was found to be an independent predictor of mortality after TAVI, the use of newer generation self expandable valves was associated with higher survival rate at 1 year irrespective of the degree of preprocedural MR. At multivariable analysis the use of newer generation valve was associated with MR improvement throughout 1 year follow-up. CONCLUSION: Baseline moderate-severe MR is associated with an increase in mortality after TAVI. However, the degree of preprocedural MR doesn't impact survival when a second generation self expandable valve is used.

Novel therapies and the best new device concepts for 2013 CAS techniques: the Mo.Ma® Proximal Occlusion System.

Recently carotid artery stenting (CAS) was upgraded in the class of recommendation among other revascularization treatments for symptomatic patients with carotid artery disease. This makes CAS potentially available to a broader range of patients. Significant evolution in CAS materials and protection devices contributed towards this improvement. Particularly in the setting of symptomatic carotid stenosis the most important cerebral protection devices available today, are the proximal protection systems. Comparing to the distal, filter-type protection devices, proximal protection systems can offer complete cerebral protection by preventing embolization of debris in the brain even before lesion crossing. In the present manuscript, we are reviewing all data regarding the efficacy of the flow-blockage proximal protection system (Mo.Ma®, Medtronic, Minneapolis, MN, US) as well as its potential advantages and drawbacks.

Late cerebral embolization after emboli-protected carotid artery stenting.

Carotid artery stenting (CAS) is nowadays considered as alternative therapeutic option to carotid endarterectomy for patients suffering from carotid artery disease. Recent studies and meta-analyses have demonstrated equal performance of carotid stenting to endarterectomy as regard as the overall adverse events (death/stroke rates), especially when periprocedural myocardial infarction and nerve pulses are also included. However, carotid stenting was inferior to endarterectomy when compared in terms of acute and late embolic events. In the present review, we collect all studies available in the published literature regarding the late embolic events. We mainly attempted to gather data regarding the silent embolic events occurring after the acute post-procedural period. We analyzed the results and reported the incidence of the problem. Finally, we aimed to identify possible causes and propose effective solutions to reduce the incidence of late embolic events.

Predictive factors for an uncomplicated long-term course of Crohn's disease: a retrospective analysis.

BACKGROUND: Predictive factors for a mild course of Crohn's disease (CD) may have therapeutic consequences, but as yet have not been identified. AIMS: To identify baseline factors that predict mild CD and design a predictive scoring system. METHODS: A retrospective, multicenter study of newly diagnosed CD patients allocated to mild CD (no therapy, mesalazine only, or mesalazine with a single initial short course of low-dose prednisone) or moderate CD (all other patients including resected patients). RESULTS: 162 patients (median follow-up 43 months) were analyzed: 47 mild CD and 115 moderate CD. For mild CD versus moderate CD, mean age at first diagnosis was higher (41.1 versus 33.9 years, p=0.02), mean C-reactive protein (CRP) concentration was lower (1.6 versus 3.6 mg/L, p<0.01), and perianal lesions were less frequent (0% versus 10.4%, p=0.02). The combined incidence of complications (stenosis, any type of fistula, extraintestinal complications or fever) was 21.3% in mild CD versus 35.7% in moderate CD (p=0.07). A scoring system based on age, CRP, endoscopic severity (adapted Rutgeert's score), perianal lesions and combined incidence of complications was developed which can predict a mild prognosis at the initial diagnosis, giving patients the chance of simplified therapy and accelerated step-up in the event of treatment failure. CONCLUSIONS: Approximately a third of CD patients experience a mild disease course and require only basic therapy. A possible scoring system to predict mild CD which may avoid overtreatment and unnecessary risks for the patient and costs is suggested.

Carotid stents: which is the best option?

Nowadays, carotid artery stenting (CAS) offers a potential alternative to carotid endarterectomy (CEA). CAS main advantages over CEA are the less invasive approach and the almost equal performance to CEA in terms of stroke prevention and complications. One of the most important factors which played significant role to CAS evolution is the progress in design of modern materials, especially stents. Today, several types of dedicated carotid stents have specific mechanical properties, which provide stents with individual characteristics making each of them suitable for specific carotid lesions and anatomies. The present review analyses the specific design and construction of modern stents, trying to point out their particular mechanical properties and characteristics. Additionally, it presents all available data published on comparison between different stent designs with the intention to identify which carotid stent is the best option for particular patient and lesion characteristics.

Deferred urgency carotid artery stenting in symptomatic patients: clinical lessons and biomarker patterns from a prospective registry.

INTRODUCTION: The aim of this prospective observational registry was to study the outcome of symptomatic patients presenting with recent TIA or minor stroke and severe carotid stenosis, submitted to early percutaneous treatment by stenting. A secondary aim was to evaluate the biological activity of the symptomatic carotid plaques by serial serum and urinary markers (PAPP-A, hs-CRP, MMP-2/MMP-9, IL-6/IL-8, TNF alpha, CD40L) measured by enzyme-linked immunosorbent assay before and after treatment. METHODS: From May 2005 to June 2006, 57 patients were enrolled in this prospective registry. All patients underwent carotid stenting using a concentric filter for cerebral protection. The procedure was performed within 24-48hrs of the last attack in patients with TIA (n=24, 42%) and between 14 and 30 days in patients with stroke (n=33, 58%). RESULTS: Successful stent implantation was achieved in all cases (100%). Adverse events at 1 month were 1 death (1.7%) and 2 TIAs (3.5%). Some of the vulnerability markers, in particular those reflecting an active systemic inflammatory process of the plaque (PAPP-A, hs-CR, and IL-6), were significantly elevated at the time of enrolment, increased after stenting and decreased after 30 days. CONCLUSION: Deferred CAS is feasible and safe in selected patients with symptomatic carotid stenosis. This preliminary study in a limited series of patients with unstable carotid plaques revealed that endovascular treatment has a satisfactory outcome considering the very high risk profile of the patient population. The evaluation of some biomarkers suggested an inflammatory role in the process of an unstable carotid plaque generating an acute cerebral event.

PRIAMUS--proximal flow blockage cerebral protectIon during carotid stenting: results from a multicenter Italian registry.

AIM: The aim of this Italian prospective registry was to evaluate the applicability and efficacy of the Mo.Ma Device (Invatec, Roncadelle, Italy) for the prevention of cerebral embolization during carotid artery stenting (CAS) in a real world population. METHODS: In 4 Italian centers, 416 patients (300 men; mean age 71.6+/-9 years) between October 2001 and March 2005 were enrolled in a prospective registry. Two-hundred and sixty-four symptomatic (63.46%) with >50% diameter stenosis and 152 (36.54%) asymptomatic patients with >70% diameter stenosis were included. The Mo.Ma Proximal Flow Blockage Embolic Protection System was used to perform protected CAS, achieving cerebral protection by endovascular clamping of the common carotid artery (CCA) and of the external carotid artery (ECA). RESULTS: Technical success, defined as the ability to establish protection with the Mo.Ma device and to deploy the stent, was achieved in 412 cases (99.03%). The mean duration of flow blockage was 4.91+/-1.1 min. Transient intolerances to flow blockage were observed in 24 patients (5.76%), but in all cases the procedure was successfully completed. No peri-procedural strokes and deaths were observed. Complications during hospitalization included 16 minor strokes (3.84%), 3 transient ischemic attacks (0.72%), 2 deaths (0.48%) and 1 major stroke (0.24%). This resulted in a cumulative rate at discharge of 4.56% all strokes and deaths, and of 0.72% major strokes and deaths. All the patients underwent thirty-day follow-up. At thirty-day follow-up, there were no deaths and no minor and major strokes, confirming the overall cumulative 4.56% incidence of all strokes and deaths rate, and of 0.72% rate of major strokes and deaths at follow up. In 245 cases (58.89%) there was macroscopic evidence of debris after filtration of the aspirated blood. CONCLUSIONS: This Italian multicenter registry confirms and further supports the efficacy and applicability of the endovascular clamping concept with proximal flow blockage in a broad patient series. Results match favorably with current available studies on carotid stenting with cerebral protection.

First clinical experiences with an endovascular clamping system for neuroprotection during carotid stenting.

OBJECTIVES: This report evaluates the feasibility and efficacy of an endovascular blood flow blockage technique to prevent intracerebral embolization of plaque debris during carotid artery stenting. METHODS: Forty-two patients were enrolled in five clinical sites in Germany and Italy with either an asymptomatic internal carotid artery stenosis > or =75% (mean 87%) or a symptomatic stenosis > or =60% (mean 85%). Cerebral protection during the stenting procedure was achieved using an endovascular clamping technique, obtained by occlusion of the external and common carotid artery via two independently inflatable balloons integrated in the Mo.Ma system. Blood with particulate plaque debris was aspirated before flow was restored. The patient's clinical and the neurological status were assessed during intervention, at discharge, and at 3 months follow-up. RESULTS: Stenting was performed in all but one patient. The mean flow occlusion time was 10.6+/-6.5 min. Transient clamping intolerance was observed in five patients (12%). In two patients, neurological deficits persisted for 2 and 12 h, respectively. Two minor strokes (4,7%) occurred at 5 and 72 h after the procedure. No major strokes or deaths were observed at 3 months follow-up. CONCLUSIONS: This first clinical experience with the Mo.Ma device substantiates the feasibility of endovascular clamping in preventing cerebral embolization during carotid artery stenting.

Treatment of an ostial and a bifurcation lesion with a new directional atherectomy device.

Two cases of directional coronary atherectomy performed with a new 8 French monorail device for selective plaque excision are illustrated. This report underlines the technical characteristics of this new device, which allows the negotiation of complex coronary anatomy and emphasises the potential utility of directional coronary atherectomy in bifurcation and ostial lesions.

[Initial clinical experience with a new percutaneous peripheral atherectomy device for the treatment of femoro-popliteal stenoses]. / Erste klinische Erfahrungen mit einem neuen Atherektomiekatheter zur Behandlung femoro-poplitealer Stenosen.

BACKGROUND: Evaluation of the efficacy and safety of a new 7F-atherectomy device (30-day endpoint) for the treatment of short and mid-length arterial lesions with a reference diameter of 2.5-7 mm. MATERIAL AND METHODS: Fifty-eight femoto-popliteal stenoses in 46 patients (67% male, mean age 66 +/- 9 years) with chronic peripheral occlusive disease of the lower limbs [Rutherford stage 2: n = 13 (28%); stage 3: n = 29 (63%), stage 4: 2 (4%), stage 5: n = 2 (4%)], were treated with directional atherectomy. Target lesion characteristics: Common femoral artery: n = 1 (2%), superficial femoral artery: n = 47 (81%); popliteal artery, n = 10 (17%); in stent n = 3 (5 %). Thirty (65 %) of the interventions were performed using an antegrade approach, 16 (35%) interventions in cross-over technique. Mean degree of stenosis was 83 +/- 11 mm, mean length of lesion was 37 +/- 37 mm. RESULTS: 6.5 +/- 2 (4-10) passes of the lesion were performed with the catheter. Three lesions were treated after predilatation, 55 (95%) interventions as primary atherectomy. In 31/58 lesions (53%) additional balloon angioplasty was performed, in 1 lesion (2%) additional stent placement was needed. The mean degree of stenosis after atherectomy was reduced to 29 +/- 20% (0-60%) after additional balloon angioplasty, it was 11 +/- 10% (0-30 %). A residual stenosis of < 50% after plain atherectomy was achieved in 55 (95%) lesions, of < 30% in 49 (84%). COMPLICATIONS: 3 (6.5%) cases of embolism of debris were detected and treated successfully by aspiration. The mean ankle-brachial index increased from 0.62 +/- 0.12 to 0.92 +/- 0.36 before discharge, and to 0.86 +/- 0.17 after 30 days. Rutherford stage after 30 days: stage 0: n = 038 (83%); Stage 1: n = 4 (8%); Stage 2: n = 3 (6%); Stage 5: n = 1 (2%). CONCLUSION: Lesions up to 8 cm in length of the femoropopliteal arteries can be treated successfully in most cases with the new atherectomy catheter. Embolism, the only complication that occurred, can be avoided by cleaning the nose cone after at least 4 passes of the lesion.

Cerebral protection with filter devices during carotid artery stenting.

BACKGROUND: Distal embolization of debris during percutaneous carotid artery stenting may result in neurological deficit. Filter devices for cerebral protection potentially reduce the risk of embolization. METHODS AND RESULTS: Elective carotid stent implantation using 3 different types of distal filter protection devices was attempted in 88 consecutive lesions (84 patients) in the internal carotid artery that had >70% diameter stenosis (mean, 78.7+/-10.7%). Procedures were performed in 3 different centers. The mean age of the patients was 69+/-8 years, 75% were men, and 35.7% had neurological symptoms. In 86 lesions, a stent was successfully implanted (97.7%). In 83 of these 86 procedures (96.5%), it was possible to position a filter device. In 53% of filters, there was macroscopic evidence of debris. Collected material consisted of lipid-rich macrophages, fibrin material, and cholesterol clefts. Neurological complications during the procedure, in the hospital, and at 30 days of clinical follow-up occurred in only one patient (1.2%). This patient suffered a minor stroke that resolved within 1 week. Two major adverse cardiac events (2.3%) occurred during the 30 days of follow-up. CONCLUSIONS: Filter protection during carotid artery stenting seems feasible and safe. In the present series, the incidence of neurological complications was low.

Electrophysiological properties of the atrioventricular node and ageing: evidence of a lower incidence of dual nodal pathways in the elderly.

AIMS: The purpose of this study was to investigate the relationship between the incidence of dual atrioventricular (AV) nodal pathways and age. Age-related changes in the AV node electrophysiological properties have rarely been investigated. AV nodal re-entrant tachycardia is more frequent in the young than in the elderly. METHODS AND RESULTS: From 1988 to 1998, premature atrial stimulation was performed in 1,435 patients referred to our institution for transoesophageal electrophysiological study. 1,276 patients (89%) with a diagnosis of ventricular pre-excitation, supraventricular arrhythmia or AV block were excluded. The study cohort consisted of the remaining 159 patients (11%) of the whole group) referred for syncope (8.2% of the subgroup), suspected ventricular pre-excitation (10.7%), suspected sinus node dysfunction (52.8%) or undetermined palpitations (28.3%). The 159 study patients were divided into 3 groups according to age: group A (11-30 years, 50 patients), group B (30-60 years, 35 patients) and group C (>60 years, 74 patients). A dual AV nodal pathway was found in 16 patients of group A (32.0%), 6 patients of group B (17.1%) and 8 patients of group C (10.8%), the difference between group A and group C being significant (P<0.05). CONCLUSION: The incidence of dual AV nodal pathways decreases with ageing, suggesting that the AV node undergoes age-related electrophysiological changes. This finding could explain the uncommon onset of AV nodal re-entrant tachycardia in the elderly.

Directional atherectomy prior to stenting in bifurcation lesions: a matched comparison study with stenting alone.

The ideal catheter-based intervention for treatment of coronary lesions at bifurcation site still has to be defined. The aim of the study was to assess the acute and long-term outcome after treatment of bifurcation lesions with directional atherectomy (DCA) and stenting in comparison with stenting alone. Thirty-one consecutive patients treated for bifurcation coronary lesions (62 lesions) with DCA and stenting in at least one branch (DCA group) were compared with a matched group of 31 patients with bifurcation coronary lesions (62 lesions) treated with stenting alone in at least one branch (non-DCA group). Procedural success was 87.1% in the DCA group compared with 100% in the non-DCA group (P = 0.03). In-hospital major adverse cardiac events (MACE) occurred only in the DCA group (12.9% vs. 0%, P = 0.03), mainly non-Q-wave myocardial infarction. After the procedure, minimum lumen diameter (MLD) and acute gain were significantly greater (P = 0.004 and P = 0.05, respectively) and % diameter stenosis was significantly lower (P = 0.05) in the main branch in the DCA group. At follow-up angiogram, MLD in the main branch was still significantly greater in the DCA group compared to the non-DCA group (2.31 vs. 1.65, respectively, P = 0.04), with no significant difference in late loss and loss index between the two groups. Restenosis rate was 28.8% in the DCA group vs. 43.5% in the non-DCA group (P = 0.13). The incidence of follow-up MACE was 29% in the DCA group compared with 48.4% in the non-DCA group, mainly due to target lesion revascularization. In conclusion, treatment of bifurcation coronary lesions with DCA and stenting was associated with greater acute gain after the procedure and greater MLD at follow-up in the main branch compared with stenting alone. Procedural myocardial infarction was more frequent in the DCA group. Restenosis rates and follow-up MACE were lower following DCA and stenting, without reaching any statistical significance.

Comparison of immediate and follow-up results of the short and long NIR stent with the Palmaz-Schatz stent.

The intrinsic characteristics of a stent including stent length may affect both procedural success and long-term outcome. The present study evaluated the immediate and follow-up results after implantation of the short and long NIR stent and compared these results with the Palmaz-Schatz stent. Between July 1995 and December 1996, stenting with a 16-mm NIR stent (NIR-16), a 32-mm NIR stent (NIR-32), or a Palmaz-Schatz stent (PS) was performed in 68, 57, and 155 lesions, respectively. There were no significant differences in the incidences of delivery failure (PS, 2.6%: NIR-16, 4.4%; NIR-32, 5.3%; p = NS) and procedural success (PS, 92%; NIR-16, 93%; NIR-32, 93%; p = NS) among the 3 groups. The reference vessel diameter was smaller in lesions with a 32-mm NIR stent than in those with a Palmaz-Schatz stent (PS, 3.14+/-0.58, NIR-16, 3.00+/-0.50; NIR-32, 2.90+/-0.47 mm; p <0.05). The lesion length was longer in lesions with a 32-mm NIR stent than in those with a Palmaz-Schatz or a 16-mm NIR stent (PS, 8.9+/-5.0; NIR-16, 11.0+/-4.1; NIR-32, 26.1+/-9.7 mm; p <0.01). After the procedure, the lesions with a 32-mm NIR stent had a smaller minimal lumen diameter than those with a Palmaz-Schatz stent (PS, 3.17+/-0.61; NIR-16, 2.99+/-0.51; NIR-32, 2.89+/-0.49 mm; p <0.01). At follow-up, a smaller minimal lumen diameter was observed in lesions with a 32-mm NIR stent than in those with a Palmaz-Schatz or a 16-mm NIR stent (PS, 2.32+/-0.98; NIR-16, 2.25+/-0.80; NIR-32, 1.68+/-0.79 mm; p <0.01). Restenosis rates were 16.5% in lesions with a Palmaz-Schatz stent, 13.3% in those with a 16-mm NIR stent, and 47.4% in those with a 32-mm NIR stent (p <0.01). Although stent delivery and procedural success of a long NIR stent were acceptable, the restenosis rate of a long NIR stent was high compared with a short NIR stent or a Palmaz-Schatz stent.

Stented segment length as an independent predictor of restenosis.

OBJECTIVES: We sought to evaluate the relation between stented segment length and restenosis. BACKGROUND: Multiple or long coronary stents are now being implanted in long lesions or in tandem lesions. A longer stented segment might result in a higher probability of restenosis. However, there is little information available on the relation between stented segment length and restenosis. METHODS: Between April 1995 and December 1996, 725 patients with 1,090 lesions underwent stenting. Lesions were divided into three groups according to the length of the stented segment: 1) group I (n = 565): stented segment length < or =20 mm; 2) group II (n = 278): stented segment length >20 but < or =35 mm; and 3) group III (n = 247): stented segment length >35 mm. RESULTS: There was no significant difference in the incidence of subacute stent thrombosis among the three groups (0.4% in group I, 0.4% in group II, 1.2% in group III; p = NS). The minimal lumen diameter (MLD) after stenting was greater in group I than in group III (3.04 +/- 0.60 mm in group I, 3.01 +/- 0.54 mm in group II, 2.91 +/- 0.58 mm in group III; p < 0.05). At follow up, a smaller MLD was observed in group III as compared with group I and group II (2.04 +/- 0.93 mm in group I, 1.92 +/- 1.00 mm in group II, 1.47 +/- 0.97 mm in group III; p < 0.01). The restenosis rates were 23.9% in group I, 34.6% in group II and 47.2% in group III (p < 0.01). Using multivariate analysis, the longer stented segment, the angiographic reference vessel diameter and the percent diameter stenosis after stenting were independent predictors of restenosis. CONCLUSIONS: The present study shows that a longer stented segment is an independent predictor of restenosis without an influence on the risk of subacute thrombosis.

Focal wall overstretching after high-pressure coronary stent implantation does not influence restenosis.

To determine if vessel wall overstretching during coronary stenting is associated with a higher restenosis rate, the intravascular ultrasound morphological evaluation was performed following ultrasound criteria. A total of 468 lesions with successful coronary Palmaz-Schatz stenting guided by intravascular ultrasound were classified into the no overstretching group (n = 295) and the overstretching group (n = 147). There were 26 lesions not classifiable due to the poststent morphology. Balloon-to-vessel ratio was 1.12 +/- 0.17 in the no focal overstretching group and 1. 20 +/- 0.20 in the overstretching group (P < 0.0002). Follow-up angiogram was performed in 77% of no focal overstretching group and in 75% of the focal overstretching group. The restenosis rate of the no focal overstretching group was 19.8% and 20.9% in the focal overstretching group, respectively (P = 0.65). Focal overstretching was more frequent following balloon oversizing. No increase in restenosis rate, found in focal overstretched stented lesions, leads us to the hypothesis of a regulation of smooth-muscle-cell proliferation activated by the normalization of blood flow and of shear stress, when stent implantation succeeds in optimally improving the lumen. Cathet. Cardiovasc. Intervent. 48:24-30, 1999.

Lower restenosis rate with stenting following aggressive versus less aggressive rotational atherectomy.

The present study evaluated the acute and follow-up results of stenting following aggressive rotational atherectomy compared with stenting following less aggressive rotational atherectomy. Recent work has demonstrated that stenting following rotational atherectomy is a promising strategy for complex and calcified lesions. However, there is little information available regarding the optimal procedural technique of rotational atherectomy to be employed before stent implantation. Between May 1995 and February 1997, 162 lesions in 126 patients were stented following rotational atherectomy because of the presence of severe calcification on fluoroscopy or intravascular ultrasound (95%). The lesions were divided as to whether aggressive rotational atherectomy was performed or not. Aggressive rotational atherectomy, defined as the use of a final burr size > or =2.25 mm and/or final burr/vessel ratio > or =0.8, was performed in 56 lesions. A less aggressive rotational atherectomy strategy was performed in 106 lesions. Procedural Q-wave (8.9% vs. 1.9%, P<0.05) and non-Q-wave (11% vs. 1.9%, P<0.05) myocardial infarctions were observed more frequently after aggressive rotational atherectomy; there was no significant difference in the incidence of other procedural complications. Although there was no significant difference in minimal lumen diameter after the procedure (3.11+/-0.68 vs. 2.99+/-0.48 mm, NS), at follow-up a greater minimal lumen diameter was observed in the lesions treated with aggressive rotational atherectomy compared to those treated with less aggressive rotational atherectomy (2.12+/-1.31 vs. 1.56+/-0.89 mm, P<0.01). Restenosis rates were 50.0% in the lesions treated without aggressive rotational atherectomy and 30.9% in those treated with aggressive rotational atherectomy (P<0.05). There was no significant difference in the incidence of restenosis with a focal pattern between the two groups (25.0% vs. 21.4%, NS). In contrast, restenosis with a diffuse pattern was lower in lesions treated with aggressive rotational atherectomy than in those without aggressive rotational atherectomy (9.5% vs. 25.0%, P<0.05). Aggressive rotational atherectomy followed by stenting is a promising strategy to reduce the restenosis rate in calcified lesions. However, the aggressive strategy is associated with an increased risk of procedural myocardial infarction.

In-stent neointimal proliferation correlates with the amount of residual plaque burden outside the stent: an intravascular ultrasound study.

BACKGROUND: The aim of this study was to evaluate the relationship between residual plaque burden after coronary stent implantation and the development of late in-stent neointimal proliferation. METHODS AND RESULTS: Between January 1996 and May 1997, 50 patients underwent intravascular ultrasound (IVUS) interrogation at 6+/-1.2 months after coronary stent implantation in native coronary arteries. IVUS images were acquired with a motorized pullback, and cross-sectional measurements were performed within the stents at 1-mm intervals. The following measurements were obtained: (1) lumen area (LA), (2) stent area (SA), (3) area delimited by the external elastic membrane (EEMA), (4) percent neointimal area calculated as (SA-LA/SA)x100, and (5) percent residual plaque area calculated as (EEMA-SA)/EEMAx100. Volume measurements within the stented segments were calculated by applying Simpson's rule. In the pooled data analysis of 876 cross sections, linear regression showed a significant positive correlation between percent residual plaque area and percent neointimal area (r=0.50, y= 45.03+0.29x, P<0.01). There was significant incremental increase in mean percent neointimal area for stepwise increase in percent residual plaque area. Mean percent neointimal area was 16.3+/-10.3% for lesions with a percent residual plaque area of <50% and 27.7+/-11% for lesions with a percent residual plaque area of >/=50% (P<0.001). The volumetric analysis showed that the percent residual plaque volume was significantly greater in restenotic lesions compared with nonrestenotic lesions (58.7+/-4.3% versus 51.4+/-5.7%, respectively; P<0.01). CONCLUSIONS: Late in-stent neointimal proliferation has a direct correlation with the amount of residual plaque burden after coronary stent implantation, supporting the hypothesis that plaque removal before stent implantation may reduce restenosis.

Angiographic and clinical outcome following coronary stenting of small vessels: a comparison with coronary stenting of large vessels.

OBJECTIVES: Stent implantation reduces restenosis in vessels > or =3 mm compared with balloon angioplasty, but few data are available for stents implanted in vessels <3 mm. The aim of this study was to evaluate immediate and follow-up patient outcomes after stent implantation in vessels <3 mm compared to stent implantation in vessels > or =3 mm. METHODS: Between March 1993 and May 1996, a total of 1,298 consecutive patients (1,673 lesions) underwent coronary stenting. The study population was divided into two groups based on angiographic vessel diameter. In case of multivessel stenting, patients were randomly assigned only one lesion. Group I included 696 patients (696 lesions) in whom stents were implanted in vessels > or =3 mm, and group II included 602 patients (602 lesions) in whom stents were implanted in vessels <3 mm. RESULTS: There was no difference in procedural success (95.4% in group I and 95.9% in group II), or subsequent subacute stent thrombosis (1.5% in group I and 1.4% in group II, p=NS). The postprocedure residual diameter stenosis was 3.31+/-12.4% in group I and -2.45+/-16.2% in group II. Angiographic follow-up was performed in 75% of patients, restenosis occurred in 19.9% of patients in group I and 32.6% in group II (p <0.0001). Absolute lumen gain was significantly higher in group I compared to group II, but absolute late lumen loss was similar in the two groups (1.05+/-0.91 mm in group I vs. 1.11+/-0.85 mm in group II, p=NS). Subsequently, the loss index was more favorable in group I (0.45 vs. 0.56; p=0.0006). Independent predictors of freedom from restenosis by multivariate logistic regression in the total population were: larger baseline reference diameter (odds ratio 2.032 p=0.006), larger postprocedure minimal stent cross-sectional area (odds ratio 1.190, p=0.0001) and shorter lesions (odds ratio 1.037, p=0.01). At long-term clinical follow-up, patients with small vessels had a lower rate of event-free survival (63% vs. 71.3%, p=0.007). CONCLUSIONS: Coronary stenting can be performed in small vessels with a high success rate and low incidence of stent thrombosis. However, the long-term angiographic and clinical outcome of patients undergoing stent implantation in small vessels is less favorable than that of patients with large vessels.