P1435 The impact of intermediate wall shear strain on changes of plaque morphology in CAD: A systematic review and meta-analysis

Background and Aim

The experimental studies found that high wall shear strain (WSS) resulted in the development of more vulnerable plaque compared to low WSS. The aim of this meta-analysis is to assess the role of intermediate WSS on atherosclerotic plaque.

Methods

We systematically searched PubMed-Medline, EMBASE, Scopus, Google Scholar and the Cochrane Central Registry from 1989 to May 2019 in order to select clinical trials and observational studies, which assessed the relationship between WSS measured by intravascular ultrasound (IVUS) and plaque morphology in CAD.

Results

A total of 32,083 segments were recruited in 7 studies with mean follow up 8.4 months. The pooled analysis showed that baseline low WSS is associated with similar plaque morphology to that with intermediate WSS: lumen area WMD 0.96 [-0.12 to 2.04, p = 0.08], plaque area WMD -0.43 [-0.09 to 0.13, p = 0.13], necrotic core area WMD -0.18 [-0.45 to 0.08, p = 0.18], dense calcium score WMD -0.12 [-0.26 to 0.02, p = 0.09] as well as fibrous WMD -0.35 [-0.89 to 0.19, p = 0.21] and fibro-fatty area WMD -0.05 [-0.12 to 0.02, p = 0.12]. At follow-up, the only difference found was an increase of fibrous WMD 0.08 [0.01 to 0.16, p = 0.04] and fibro-fatty area, WMD 0.07 [0.01 to 0.12, p = 0.02] in low WSS compared intermediate WSS.

Conclusions

Intermediate WSS group is associated with plaque features changes similar to those occurring with low WSS. This finding emphasis the role of IVUS in outcome of atherosclerotic plaque in CAD.

Left and right ventricular diastolic functions in patients with rheumatoid arthritis without clinically evident cardiovascular disease

The aim of this study was to assess the prevalence of diastolic dysfunction of the left ventricle (LV) and of the right ventricle in patients with rheumatoid arthritis (RA) without clinically evident cardiovascular manifestations and to estimate whether there is a correlation between the duration of RA and the degree of LV diastolic dysfunction. The study included 81 patients (61 females and 20 males) with RA without clinically evident heart disease (group 1) and 40 healthy subjects (29 females and 11 males) who served as a control group (group 2). Both groups were matched for age and sex. Echocardiographic and Doppler studies were conducted in all patients with RA and control subjects. There were significant differences between patients with RA vs. control group with regard to early diastolic flow velocity (E), atrial flow velocity (A) and the E/A ratio (0.68 +/- 0.19 m/s vs. 0.84 +/- 0.14 m/s, p < 0.001; 0.73 +/- 0.15 m/s vs. 0.66 +/- 0.13 cm/s, p = 0.01; and 0.97 +/- 0.3 vs. 1.32 +/- 0.37, p < 0.001, respectively). There was significant difference between groups regarding the right ventricular early diastolic (Er)/atrial (Ar) flow velocities (Er/Ar ratio) (1.07 +/- 0.3 vs. 1.26 +/- 0.3, p = 0.002). There was a weak correlation between transmitral E/A ratio and the duration of RA (r = - 0.22, p = 0.001). Myocardial performance index (MPI) appeared to differ little in patients with RA as compared with control group (0.51 +/- 0.1 vs. 0.52 +/- 0.2, p = NS). In patients with RA without clinically evident cardiovascular disease, the left ventricular diastolic function and the right ventricular diastolic function are reduced. Left ventricular wall thickness, dimensions, systolic function and MPI were found to be normal. LV diastolic function had a weak correlation with the duration of RA.

Current drug-eluting stents in complex patients and lesions

Drug-eluting stents (DES) are playing an increasingly important role in the treatment of coronary artery disease. These new devices work by releasing controlled amounts of pharmacological agents with anti-restenosis properties at the implantation site. Most of them use polymer coating as a drug carrier, but concerns about long-term negative effects of a permanent polymer coating have stimulated the development of non-polymer DES or DES based on bioabsorbable polymers. Several randomized studies with DES have demonstrated their superiority over bare metal stents mostly in selected patients and lesion subsets. Accumulating evidence is showing significant differences in performance between currently used DES. These differences are more pronounced in complex, high-risk subsets of patients and lesions and should be considered during the process of DES selection for the individual patient. Interventional cardiologists have learned that patients who receive DES require a more prolonged antiplatelet therapy, but the optimal length and regimen are still unclear and further investigations are needed. Major advances in interventional cardiology have caused a dramatic shift away from aorto-coronary bypass surgery and an increase in the complexity of percutaneous coronary interventions. Observational and specifically designed randomized studies are currently addressing the issue of the role of DES in complex situations including in-stent restenosis, ostial and bifurcation lesions, chronic occlusions, small vessels, long lesions, saphenous vein grafts, multivessel disease, left main disease, acute myocardial infarction and diabetes mellitus. Although definitive answers are still to come from ongoing research, available data support the use of DES in most of these situations.

Influence of stent design on 1-year outcome after coronary stent placement: a randomized comparison of five stent types in 1,147 unselected patients

The objective of this randomized trial was to assess whether differences in stent design are translated in different clinical outcomes in patients undergoing coronary stent placement. This multicenter randomized trial included 1,147 patients who were randomly assigned to receive one of five types of stainless steel stents: Inflow, MULTI-LINK, NIR, Palmaz-Schatz, and PURA-A stent. Primary endpoint of the study was event-free survival at 1 year. Event-free survival at 1 year was significantly different between the groups (P = 0.014), ranging from 69.4% to 82.4%. Similarly, freedom from myocardial infarction was also significantly different (P = 0.022), with values between 88.2% and 95.2%. Diameter stenosis at 6 months varied from 38.1% +/- 25.0% to 45.6% +/- 27.7% (P = 0. 046), late lumen loss ranged from 1.01 +/- 0.70 mm to 1.20 +/- 0.82 mm (P = 0.085), and the incidence of restenosis varied between 25.3% and 35.9% (P = 0.145). Thus, stent design has a significant impact on the long-term results after coronary stent placement.

Clinical and angiographic follow-up after balloon angioplasty with provisional stenting for coronary in-stent restenosis

The objective of this study was to assess the angiographic and clinical outcome of patients with coronary in-stent restenosis treated with balloon angioplasty with provisional stenting. The study included 375 consecutive patients with in-stent restenosis managed with balloon angioplasty alone or combined with stenting. Clinical events were recorded during a 1-year follow-up period and quantitative analysis was performed on 6-month angiographic data. Of the 373 patients (451 lesions) with a successful procedure, 273 were treated with angioplasty alone and 100 with additional stenting. Target lesion revascularization was required in 23.7% of the patients: 20.7% in patients with angioplasty and 31.0% in patients with stenting. Angiographic restenosis rate was 38.9%: 35.8% in the angioplasty group and 47.7% in the stent group. Stenting in small vessels was associated with a much higher restenosis rate than in larger vessels (65.6% vs. 37.5%, respectively; P = 0.01). Thus, repeat balloon angioplasty with provisional stenting for in-stent restenosis is a safe treatment strategy associated with a relatively favorable long-term outcome. However, the long-term results might be improved if additional stenting is avoided especially in small vessels. Cathet. Cardiovasc. Intervent. 48:151-156, 1999.

Prognostic value of the modified american college of Cardiology/American heart association stenosis morphology classification for long-term angiographic and clinical outcome after coronary stent placement

Background-The modified American College of Cardiology/American Heart Association (ACC/AHA) lesion morphology criteria are predictive of early outcome after various coronary catheter interventions. Their potential prognostic value after stent implantation and, in particular, for restenosis and long-term clinical outcome has not been studied. We assessed the prognostic value of the modified ACC/AHA criteria for the long-term angiographic and clinical outcome of patients after coronary stenting. Methods and Results-This study includes 2944 consecutive patients with symptomatic coronary artery disease treated with coronary stent placement. Modified ACC/AHA lesion morphology criteria were used to qualitatively assess the angiograms; type A and B1 lesions were categorized as simple, and type B2 and C lesions were designated complex. Primary end points were angiographic restenosis and 1-year event-free survival. Restenosis rate was 33.2% in complex lesions and 24.9% in simple lesions (P<0.001). It was 21. 7% for type A, 26.3% for type B1, 33.7% for type B2, and 32.6% for type C lesions. One-year event-free survival was 75.6% for patients with complex lesions and 81.1% for patients with simple lesions (P<0. 001). It was 85.2% for patients with type A, 79.4% for type B1, 75. 9% for type B2, and 75.2% type C lesions. The higher risk for restenosis and an adverse outcome associated with complex lesions was also maintained after multivariate adjustment for other clinical and angiographic characteristics. Conclusions-The modified ACC/AHA lesion morphology scheme has significant prognostic value for the outcome of patients after coronary stent placement. Lesion morphology is able to influence the restenosis process and thus the entire 1-year clinical course of these patients.

Influence of balloon pressure during stent placement in native coronary arteries on early and late angiographic and clinical outcome: A randomized evaluation of high-pressure inflation

BACKGROUND

High-pressure dilatation is considered a better stent placement strategy, but this has not yet been proved by appropriately designed studies. The objective of this randomized trial was to assess the role of high-pressure dilatation in the early and late outcome of patients undergoing coronary stent placement.

METHODS AND RESULTS

Consecutive patients with coronary stent placement were randomly assigned to high- (15 to 20 atm, 468 patients) or low- (8 to 13 atm, 466 patients) balloon-pressure dilatation. The primary end point of the study was the event-free survival at 1 year. Secondary end points were the incidence of stent thrombosis at 30 days and angiographic restenosis (>/=50% diameter stenosis) at 6 months. The incidence of stent thrombosis was 1.7% in the high-pressure and 1.9% in the low-pressure group (relative risk 0.89; 95% CI 0.30 to 2.56). During the first 30 days, although there was no significant difference in the incidence of Q-wave myocardial infarction, the incidence of non-Q-wave infarction was 6.4% in the high-pressure and 3.4% in the low-pressure group (relative risk 1. 87; 95% CI 1.02 to 3.42). The restenosis rate was 30.4% in the high-pressure and 31.4% in the low-pressure group (relative risk 0. 97; 95% CI 0.75 to 1.26). Event-free survival at 1 year was not significantly different between the groups, with 78.8% in high-pressure patients and 75.5% in patients assigned to low-pressure dilatation (hazard ratio 0.85; 95% CI 0.65 to 1.11).

CONCLUSIONS

The systematic use of high-balloon-pressure inflation (15 to 20 atm) during coronary stent placement is not associated with any significant influence on the 1-year outcome of patients undergoing this intervention.

Influence of lesion length on restenosis after coronary stent placement

The length of a coronary lesion is a significant predictor of restenosis after balloon angioplasty. The influence of lesion length has not comprehensively been assessed after coronary stent placement. This study includes 2,736 consecutive patients with coronary stent placement. Only patients with recent or chronic occlusions before the intervention were excluded. Patients were divided in 2 groups: 573 patients with long lesions (> or = 15 mm) and 2,163 patients with short lesions (< 15 mm). There were no significant differences between the groups with respect to the procedural success rate and incidence of subacute thrombosis. One-year event-free survival was lower in patients with long lesions (73.3% vs 80.0%, p = 0.001). Six-month angiography was performed in 82.5% of the eligible patients. The incidence of binary restenosis (> or = 50% diameter stenosis) was higher in patients with long lesions (36.9% vs 27.9%, p <0.001). Similarly, patients with long lesions presented more late lumen loss than those with short lesions (1.29 +/- 0.89 vs 1.07 +/- 0.77 mm, p <0.001). Multivariate models for both binary restenosis and late lumen loss demonstrated that lesion length was an independent risk factor for restenosis. The risk was further increased by multiple stent placement and overlapping stents that were also independent risk factors of restenosis. Stented segment length did not show any independent effect. Therefore, long lesions represent an independent risk factor for restenosis after coronary stent placement. The results of this study suggest that a possible way to reduce the risk is to cover the lesion with a minimal number of nonoverlapping stents.

Lipoprotein(a) and coronary thrombosis and restenosis after stent placement

OBJECTIVES

The objective of this prospective study was to evaluate the relation between high lipoprotein(a) levels and thrombotic and restenotic events after coronary stent implantation.

BACKGROUND

Lipoprotein(a) may promote atherogenesis, coronary thrombosis and restenosis after balloon angioplasty, but the clinical significance remains unclear.

METHODS

The study included 2,223 consecutive patients with successful coronary stent placement. According to the serum level of lipoprotein(a), patients were divided in two groups: 457 patients of the highest quintile formed the high lipoprotein(a) group, and 1,766 patients of the lower four quintiles formed the low lipoprotein(a) group. Primary end points were the incidence of angiographic restenosis at six months and the event-free survival at one year. Secondary end point was the incidence of angiographic stent occlusion.

RESULTS

Early stent occlusion occurred in four of the 457 patients (0.9%) with high and 37 of the 1,766 patients (2.1%) with low lipoprotein(a) levels, odds ratio of 0.41 (95% confidence interval, 0.15 to 1.16). Angiographic restenosis occurred in 173 of the 523 lesions (33.2%) in the high lipoprotein(a) group and 636 of the 1,943 lesions (32.7%) in the low lipoprotein(a) group, odds ratio of 1.02 (0.83 to 1.25). The probability of event-free survival was 73.0% in the high lipoprotein(a) group and 74.8% in the low lipoprotein(a) group (p = 0.45). On the basis of the findings in the low lipoprotein(a) group, the power of this study to detect a 25% increase in the incidence of restenosis and adverse events in the group with elevated lipoprotein(a) was 90% and 75%, respectively.

CONCLUSIONS

Elevated lipoprotein(a) levels did not influence the one-year clinical and angiographic outcome after stent placement. Thrombotic events and measures of restenosis were not adversely affected by the presence of high lipoprotein(a) levels.

PlA polymorphism of platelet glycoprotein IIIa and risk of restenosis after coronary stent placement

BACKGROUND

Platelets play a central role in the process of restenosis after percutaneous coronary interventions. A polymorphism of platelet glycoprotein IIIa (PlA) has been associated with a higher risk of coronary thrombosis. We designed this prospective study to test the hypothesis that PlA polymorphism of glycoprotein IIIa is associated with an increased risk for restenosis after coronary stent placement.

METHODS AND RESULTS

The study included 1150 consecutive patients with successful coronary stent placement and 6-month follow-up with coronary angiography. The end point of the study was the incidence of angiographic restenosis (>/=50% diameter stenosis) at follow-up. Of the 1150 patients, 72.5% were homozygous for PlA1, 24.7% were heterozygous (PlA1/A2), and 2.8% were homozygous for PlA2. Patients with the PlA2 allele demonstrated a significantly higher restenosis rate than did those without (47% versus 38%; OR, 1.42; 95% CI, 1.09 to 1.84). The risk was highest in homozygous carriers of PlA2 (53.1% restenosis rate). After adjustment for several clinical and angiographic characteristics, the presence of the PlA2 allele remained a significantly independent risk factor for restenosis (adjusted OR, 1.35; 95% CI, 1.07 to 1.70). The influence of the PlA2 allele on restenosis was stronger in women. Women with PlA2 had a restenosis rate of 52% compared with the 33% incidence among women homozygous for PlA1 (OR, 2.21; 95% CI, 1.27 to 3.85).

CONCLUSIONS

This study showed a significant association between the PlA polymorphism of glycoprotein IIIa and the risk of restenosis after coronary stent placement. The risk was more pronounced in patients homozygous for PlA2 allele and in female patients.

Coronary artery stent placement with postprocedural antiplatelet therapy in acute myocardial infarction

BACKGROUND

We have shown that coronary artery stent implantation in acute myocardial infarction (AMI) is feasible and safe when combined with effective postprocedural antiplatelet therapy. However, the concept of coronary stenting in AMI has not been validated in large cohorts. In this observational study, we investigated the outcome in 318 consecutive patients.

METHODS AND RESULTS

From January 1995 until December 1996, 420 of 455 (92.3%) patients admitted to our institutions with AMI underwent infarct artery stent placement. This report describes the 318 patients treated with combined antiplatelet therapy whose AMI was not complicated by cardiogenic shock or mechanical ventilation before the intervention. Postinterventional therapy consisted of 100 mg aspirin and 250 mg ticlopidine twice daily. There were 21 (6.6%) cardiac events during 30-day follow-up: five cardiac deaths (1.6%), four nonfatal re-infarctions (1.3%) and 13 target vessel revascularizations (4.1%). Six months of clinical follow-up yielded a 94.7% survival rate free of repeat AMI. The rate of repeat interventions was 11%. Quantitative computerized angiography at 6 months, performed in 79.4% of the eligible patients, revealed a binary restenosis rate of 25%.

CONCLUSIONS

With postprocedural antiplatelet therapy, coronary stenting in AMI yields favorable short- and long-term outcomes.

Diabetes mellitus and the clinical and angiographic outcome after coronary stent placement

OBJECTIVES

The objectives of this study were to analyze the clinical and angiographic outcome of diabetic patients with successful coronary stent placement and to compare these results with those achieved after stenting in nondiabetic patients.

BACKGROUND

The outcome of diabetic patients treated with stent placement due to coronary artery disease has not been assessed comprehensively.

METHODS

This study analyzes a consecutive series of patients with successful stent placement comprising 715 patients with diabetes and 2,839 patients without diabetes. Clinical one year follow-up and angiographic control at 6 months were part of the protocol. Death, myocardial infarction and target lesion revascularization were considered as adverse events. An automated edge detection system was used for the angiographic assessment. The primary clinical endpoint was event-free survival at one year. The primary angiographic endpoint was restenosis rate at 6 months (> or = 50% diameter stenosis).

RESULTS

Event-free survival was significantly lower in diabetic than in nondiabetic patients (73.1 vs. 78.5%, p < 0.001). Survival free of myocardial infarction was also significantly reduced in the diabetic group (89.9 vs. 94.4% in nondiabetics, p < 0.001). The incidence of both restenosis (37.5 vs. 28.3%, p < 0.001) and stent vessel occlusion (5.3 vs. 3.4%, p = 0.037) was significantly higher in diabetic patients. Diabetes was identified as an independent risk factor for adverse clinical events and restenosis in multivariate analyses.

CONCLUSIONS

Patients with diabetes mellitus have a less favorable clinical outcome at one year after successful stent placement as compared to the nondiabetic patients. The clinical follow-up was characterized by a higher incidence of death, myocardial infarction and reinterventions. Diabetic patients also demonstrated an increased risk for restenosis.

Vessel size and long-term outcome after coronary stent placement

BACKGROUND

The role of coronary stenting in the treatment of patients with small vessels is not well defined. The purpose of this study was to investigate the influence of vessel size on long-term clinical and angiographic outcome after coronary stent placement.

METHODS AND RESULTS

The study comprised 2602 patients with successful stent implantation for symptomatic coronary artery disease. Patients were subdivided into 3 equally sized groups (tertiles) according to vessel size, with respective ranges of <2.8, 2.8 to 3.2, and >3.2 mm. Event-free survival at 1 year was 69.5% in the group with smaller vessels, 77.5% in the second group, and 81% in the group with larger vessels (P<0.001). Late lumen loss was similar between the 3 groups (1.12+/-0.73, 1.12+/-0.79, and 1.09+/-0. 88 mm, respectively). Angiographic restenosis rate was significantly higher in the small-vessel group (38.6%, 28.4%, and 20.4% in groups 1, 2, and 3, respectively; P<0.001). The analysis identified subgroups with different risk for restenosis even among patients with small vessels. Within this group, the restenosis rate may be as low as 29.6% in patients without additional risk factors and as high as 53.5% in patients with diabetes and complex lesions.

CONCLUSIONS

Patients with small vessels present a higher risk for an adverse outcome after coronary stent placement because of a higher incidence of restenosis. However, the unusually high risk for restenosis is confined to those patients with small vessels who have concomitant risk factors such as diabetes and complex lesions.

Clinical and angiographic outcome after stent placement for chronic coronary occlusion

A consecutive series of 132 patients with total chronic coronary occlusions were compared with 1,966 patients with stenotic lesions in terms of angiographic and clinical outcome. We concluded that patients with chronically occluded coronary lesions present a higher rate of target lesion revascularizations and angiographic restenosis than patients with stenotic lesions.

Intracoronary stenting and risk for major adverse cardiac events during the first month

BACKGROUND

Our rationale for this study was to analyze the risk for procedural failure of attempted stenting and the risk for major adverse cardiac events (MACE) after success and to develop a risk stratification protocol for successful procedures.

METHODS AND RESULTS

Stenting was attempted in 2894 procedures during the 5-year study period (success in 98.3% of 3815 lesions). After failure, the MACE rate was 42.6%. The risk for failure was higher for lesions in the left circumflex coronary artery or in venous bypass grafts and after an acute occlusion before stenting; it increased with stenosis length or grade and decreased with vessel size and growing institutional experience in stenting. After success, death occurred in 0.8%, death or myocardial infarction in 2.0%, and any MACE in 3.6%. Independent risk factors for MACE were older age, diabetes, acute myocardial infarction, unstable angina, impaired left ventricular function, residual dissections, stent overlap, longer stented segments, and a postprocedural regimen without ticlopidine. Procedural factors were substantially stronger predictors than operator-independent variables available before procedures. Overall, the risk declined after the first 3 days. Two major factors exhibited time-dependent variations of their influence: while residual dissections were the dominant risk factor within the first 3 days with a reduction after that, no protective effect of ticlopidine could be identified before day 3. From these results, we derived a risk stratification protocol for individual procedures.

CONCLUSIONS

These results underscore the importance of optimal angiographic results and the need for antiplatelet regimens with immediate onset. Our risk stratification protocol may guide individual postprocedural care and allow us to compare risk profiles of different study populations and to devise quality control programs for stenting.

Interlesion dependence of the risk for restenosis in patients with coronary stent placement in in multiple lesions

BACKGROUND

Little is known about the behavior with regard to restenosis of multiple lesions within the same patient treated with intracoronary stenting. Our objective was to test the hypothesis that there is an intrapatient dependence of restenosis between lesions.

METHODS AND RESULTS

Quantitative analysis was carried out on angiograms obtained before, immediately after, and at 6 months after coronary stent placement in 1734 lesions in 1244 patients. We used a specialized logistic regression that not only accounts for intraclass correlation but also quantifies it in the form of odds ratio (OR) as the change in risk of a lesion to develop restenosis if another companion lesion had restenosis. The model was based on 23 patient- and lesion-related variables with binary restenosis (diameter stenosis > or =50%) as end point. The overall restenosis rate was 27.5%: 24.4% for single-lesion, 28.6% for double-lesion, and 33.8% for > or =3-lesion interventions. After adjustment for the influence of significant factors (hypercholesterolemia, systemic arterial hypertension, diabetes mellitus, previous PTCA, ostial lesion, location in left anterior descending coronary artery, number of stents placed, vessel size, stenosis severity, balloon-to-vessel ratio, and final result), the analysis found a significant intrapatient correlation, OR 2.5 (1.8 to 3.6). This means that in patients with multilesion interventions, the risk of a lesion to develop restenosis is 2.5 times higher if a companion lesion has restenosis, independently of the presence or absence of analyzed patient risk factors (eg, diabetes).

CONCLUSIONS

This study demonstrates that there is a dependence of restenosis between coronary lesions in patients who undergo a multilesion intervention. The likelihood of restenosis for a lesion is higher when another companion lesion has also developed restenosis. Other, as yet unidentified patient factors may be the source of this intrapatient correlation of restenosis.

Bimodal distribution of angiographic measures of restenosis six months after coronary stent placement

BACKGROUND

Restenosis has been perceived as the tail end of a normal distribution of the response of the vessel to the intervention. However, recent studies have described a bimodal distribution for de novo lesions after percutaneous transluminal coronary angioplasty. This finding suggests that some lesions may be more susceptible for restenosis. Whether this holds true for a wider spectrum of lesions undergoing stent placement is not yet known. The present study analyzes the frequency distribution of angiographic indexes of restenosis 6 months after coronary stent implantation.

METHODS AND RESULTS

Quantitative angiographic evaluation was performed in 1084 lesions of 1084 patients before, immediately after, and 6 months after successful Palmaz-Schatz stent placement; this represented 80.4% of patients eligible for follow-up angiography. Principal end points of the analysis were angiographic indexes of restenosis at 6 months. Twenty-two lesions that became totally occluded at follow-up were excluded from most parts of the analysis. Diameter stenosis, minimal luminal diameter (MLD), and lumen loss at 6 months did not follow a normal pattern; the bimodal pattern was demonstrated through deconvolution that yielded two separate normal components delineating two lesion populations, which developed distinctively different degrees of lumen renarrowing. The first and larger subgroup of lesions, which was less prone to restenosis, was centered around a mean value of 27% for diameter stenosis and 2.19 mm for MLD, whereas the second subgroup, with a greater tendency for restenosis, was situated around a mean value of 68% for diameter stenosis and 0.76 mm for MLD. The intersection point between the two theoretical normal distribution components was 53.5% for diameter stenosis and 1.09 mm for MLD at follow-up.

CONCLUSIONS

Frequency-distribution curves of angiographic indexes of restenosis after coronary stent placement have a bimodal pattern, suggesting the existence of two distinct populations with different propensity to restenosis. These findings may encourage future efforts for the timely identification of the subset with a higher risk as the target of specific antirestenotic strategies.

Predictive factors of restenosis after coronary stent placement

OBJECTIVES

The objective of this study was to identify clinical, lesional and procedural factors that can predict restenosis after coronary stent placement.

BACKGROUND

Coronary stent placement reduces the restenosis rate compared with that after percutaneous transluminal coronary angioplasty (PTCA). However, restenosis remains an unresolved issue, and identification of its predictive factors may allow further insight into the underlying process.

METHODS

All patients with successful coronary stent placement were eligible for this study unless they had had a major adverse cardiac event during the 1st 30 days after the procedure. Of the 1,349 eligible patients (1,753 lesions), follow-up angiography at 6 months was performed in 80.4% (1,084 patients, 1,399 lesions). Demographic, clinical, lesional and procedural data were prospectively recorded and analyzed for any predictive power for the occurrence of late restenosis after stenting. Restenosis was evaluated by using three outcomes at follow-up: binary restenosis as a diameter stenosis > or =50%, late lumen loss as lumen diameter reduction and target lesion revascularization (TLR) as any repeat PTCA or coronary artery bypass surgery involving the stented lesion.

RESULTS

Multivariate analysis demonstrated that diabetes mellitus, placement of multiple stents and minimal lumen diameter (MLD) immediately after stenting were the strongest predictors of restenosis. Diabetes increased the risk of binary restenosis with an odds ratio (OR) [95% confidence interval] of 1.86 [1.56 to 2.16] and the risk of TLR with an OR of 1.45 [1.11 to 1.80]. Multiple stents increased the risk of binary restenosis with an OR of 1.81 [1.55 to 2.06] and that of TLR with an OR of 1.94 [1.66 to 2.22]. An MLD <3 mm at the end of the procedure augmented the risk of binary restenosis with an OR of 1.81 [1.55 to 2.06] and that of TLR with an OR of 2.05 [1.77 to 2.34]. Classification and regression tree analysis demonstrated that the incidence of restenosis may be as low as 16% for a lesion without any of these risk factors and as high as 59% for a lesion with a combination of these risk factors.

CONCLUSIONS

Diabetes, multiple stents and smaller final MLD are strong predictors of restenosis after coronary stent placement. Achieving an optimal result with a minimal number of stents during the procedure may significantly reduce this risk even in patients with adverse clinical characteristics such as diabetes.

Restenosis after coronary stent placement and randomization to a 4-week combined antiplatelet or anticoagulant therapy: six-month angiographic follow-up of the Intracoronary Stenting and Antithrombotic Regimen (ISAR) Trial

BACKGROUND

Platelets and mural thrombus at the lesion site may play a key role in initiating the restenosis process after coronary interventions. The ISAR Trial provides a comparison of the outcomes of patients randomized to two different antithrombotic regimens administered for 4 weeks after successful coronary stent placement: combined antiplatelet therapy (aspirin plus ticlopidine) or a conventional anticoagulant regimen (phenprocoumon with initial overlapping heparin plus aspirin). Within the first 4 weeks after stent placement, combined antiplatelet therapy has been associated with a significant reduction of ischemic complications. In the present study, we examined whether combined antiplatelet therapy administered for 4 weeks after stent placement is able to reduce the process of restenosis at 6 months.

METHODS AND RESULTS

Of 517 patients initially randomized, 496 were eligible for 6-month angiographic follow-up. Scheduled angiography was performed in 432 of the eligible patients (87.1%), 216 in each group. In a comparison of the two groups, there were no significant differences in clinical and procedural variables or in qualitative and quantitative lesion characteristics before and after stenting. At 6 months, minimal luminal diameter was 1.95+/-0.86 mm in the group with initial combined antiplatelet therapy and 1.90+/-0.87 mm in the group with initial anticoagulant therapy (P=.55). Late lumen loss was 1.10+/-0.81 and 1.15+/-0.75 mm (P=.54), and the restenosis rate was 26.8% and 28.9%, respectively (P=.70). Target lesion revascularization rate was 14.6% in the antiplatelet therapy group and 15.6% in the anticoagulant therapy group (P=.85).

CONCLUSIONS

This study shows that combined antiplatelet therapy (aspirin plus ticlopidine) administered for 4 weeks after coronary Palmaz-Schatz stent placement does not result in a detectable benefit for the prevention of restenosis compared with conventional anticoagulant therapy (phenprocoumon with initial overlapping heparin plus aspirin).