Effect of intracoronary stenting on intimal dissection after balloon angioplasty: results of quantitative and qualitative coronary analysis

The effect of the Palmaz-Schatz stent on the angiographic appearance and residual luminal stenosis in patients with intimal dissection after balloon angioplasty was evaluated in 84 consecutive patients (90 lesions). Coronary angiography was performed before angioplasty, after conventional angioplasty and after stent implantation. The degree of intimal disruption was assessed as follows: grade 0, no dissection; grade 1, simple dissection (intraluminal linear defect or extraluminal cap extravasation); or grade 2, complex dissection (nonlinear spiral defect or luminal defect with multiple irregular borders). Quantitative coronary analysis of digitized cineangiograms was performed with use of a computerized automatic edge detection algorithm. After balloon angioplasty, 31 (34%) of 90 lesions demonstrated intimal dissection (18 simple, 13 complex). After stent implantation, intimal dissection improved by greater than or equal to 1 grade in 29 (94%) of the 31 lesions with 27 (87%) reduced to grade 0 (that is, no dissection). Dissection grade improved after stenting in 16 (89%) of 18 simple dissections and in all 13 complex dissections. Mean diameter stenosis was 77 +/- 17% before angioplasty, 47 +/- 17% after angioplasty and 14 +/- 10% after stenting (before angioplasty vs. after angioplasty and after angioplasty vs. after stenting, p less than 0.0001). In conclusion, intracoronary stenting is effective in reducing the residual luminal stenosis and in improving the angiographic appearance of intimal dissections after conventional balloon angioplasty.     

Coronary hemodynamics of stent implantation after suboptimal and optimal balloon angioplasty

OBJECTIVES: This study was performed to evaluate hemodynamic alterations of stent implantation after Doppler flow-guided balloon angioplasty (BA). BACKGROUND: There is controversy regarding the effect of stent implantation on coronary hemodynamics after suboptimal and optimal BA. METHODS: A total of 523 of 620 patients underwent Doppler-guided BA in the setting of a multicenter study and were analyzed before and after additional stent implantation. Balloon angioplasty was considered optimal when the diameter stenosis (DS) was < or = 35% and coronary flow reserve (CFR) was >2.5 and suboptimal if these two criteria were not met. Coronary flow reserve was also measured in an angiographically normal artery to determine relative CFR. Patients were followed for 12 months to document major adverse cardiac events (MACE). RESULTS: The main difference between patients with suboptimal BA (n = 195 [51%]) and optimal BA (n = 184 [49%]) was a more pronounced increase in baseline blood flow velocity (15 +/- 8 to 22 +/- 11 vs. 14 +/- 8 to 16 +/- 10 cm/s, p < 0.01). Coronary flow reserve improved after stent implantation in both patient groups, owing to a reduction in residual lumen obstruction, as determined by angiographic (%DS) and Doppler flow criteria (hyperemic blood flow velocity, relative CFR), and was associated with a decrease in MACE (16% vs. 7% in optimal BA group, p = 0.08; and 27% vs. 11% in suboptimal BA group, p = 0.007). CONCLUSIONS: Stent implantation enhances CFR after suboptimal and optimal Doppler-guided BA, owing to a reduction in residual lumen obstruction-determined by angiographical and Doppler flow criteria-as the underlying mechanism for an improved clinical outcome.     

Tissue proliferation within and surrounding Palmaz-Schatz stents is dependent on the aggressiveness of stent implantation technique

In-stent restenosis is entirely due to intimal hyperplasia. Histologic studies have indicated that intimal hyperplasia is related to the arterial injury induced during stent implantation. We used intravascular ultrasound (IVUS) imaging to study whether tissue proliferation inside and surrounding stents is related to the aggressiveness of the implantation technique. After intervention and follow-up (mean 5.6 +/- 3.7 months), serial IVUS imaging was performed in 102 native artery stented stenoses in 91 patients. Measurements at 5 predetermined segments within each stented lesion included external elastic membrane, stent, and lumen cross-sectional areas (CSAs). Calculations included mean plaque CSA growth outside of the stent (external elastic membrane-stent) and mean neointimal hyperplasia CSA and thickness within the stent (stent-lumen). Stenoses were categorized depending on the aggressiveness of stent placement (group 1, adjunct percutaneous transluminal coronary angioplasty pressure < 16 atm and/or balloon/artery ratio < 1.1; group 2, adjunct percutaneous transluminal coronary angioplasty pressure > or = 16 atm and balloon/artery ratio > or = 1.1). An aggressiveness score was calculated as balloon/artery ratio x inflation pressure. Mean intimal hyperplasia CSA (2.9 +/- 1.5 vs 2.2 +/- 1.6 mm2, p = 0.028), mean intimal hyperplasia thickness (0.34 +/- 0.19 vs 0.25 +/- 0.19 mm, p = 0.012), and mean peristent tissue growth CSA (2.5 +/- 1.0 vs 1.1 +/- 1.4 mm2, p = 0.003) were significantly greater in group 2 stenoses. In addition, intimal hyperplasia CSA and thickness correlated significantly with balloon/artery ratio x inflation pressures: r = 0.305, p = 0.002 and r = 0.329, p = 0.0007, respectively, as did peristent tissue proliferation CSA (r = 0.466, p = 0.001). Tissue proliferation inside and surrounding stents may be related to aggressiveness of the stent implantation technique.     

Changes in antibody titers against Chlamydia pneumoniae after coronary angioplasty

OBJECTIVES: The potential role of common infectious agents in the pathogenesis and progression of atherosclerosis has been studied increasingly over the last decade. The evidence for Chlamydia pneumoniae as a potential causative agent is strong and is based on the findings of numerous sero-epidemiological studies, examination of atheromatous plaque specimens, in vitro animal models. We performed a prospective study in percutaneous transluminal coronary angioplasty (PTCA) patients to investigate whether the angioplasty procedure influenced the specific humoral immune response reaction against C. pneumoniae antigens. METHODS: We studied 76 patients who successfully underwent PTCA for de novo lesions. Blood samples were drawn immediately before PTCA and 1 month after PTCA. IgG and IgA antibodies against C. pneumoniae (strain CDC/CWL-029) were determined by an in-house developed enzyme immunoassay. RESULTS: At the time of angioplasty 75% and 34% of the patients had seropositive antibodies to elementary bodies (EBs) of classes IgG and IgA, respectively. Mean titers of IgG antibodies before and 1 month after PTCA were 46+/-31 and 50+/-28 relative units (RU/ml) (P>0.05). One month after PTCA, 97% and 34% of the patients had seropositive antibodies to EBs of classes IgG and IgA, respectively. We divided our patients into two groups on the basis of IgG seropositivity (group I: Chlamydia antibody IgG seronegative patients, group II: Chlamydia antibody IgG seropositive) before PTCA. Significant increase in the antibody titers of IgG (12+/-5 vs. 40+/-18, P<0.001) and IgA (0.6+/-0.33 vs. 1.15+/-0.83, P=0.007) was observed in group I patients 1 month after PTCA and 88% of them gained IgG seropositivity. There were no significant changes in IgG and IgA antibody levels in group II after PTCA. CONCLUSION: We have demonstrated a statistically significant rise in C. pneumoniae antibodies (especially IgG) induced by PTCA in patients previously seronegative.     

Physiologically guided angioplasty in support to a provisional stenting strategy: immediate and six-month outcome.

The results of an observational multicenter angioplasty study suggested that stenting decisions may be facilitated by physiologic data. The purpose of this study was to evaluate the early and long-term clinical and angiographic outcome of prospective physiologically guided provisional stenting. Coronary angioplasty using a Doppler-tipped angioplasty guidewire was performed in 68 patients. The provisional stent strategy dictated that balloon angioplasty was to be continued until a coronary flow reserve was >/= 2.2 with a residual diameter stenosis by quantitative coronary angiography < 35%. Repeat coronary angiography was obtained at 6 months. Based on the study criteria, 32/68 patients (47%) received a stent. Compared to the stent group, the angioplasty alone group had higher postprocedural stenosis (23% +/- 13% vs. 13% +/- 10%; P < 0. 05) and lower coronary vasodilatory reserve (2.3 +/- 0.4 vs. 2.6 +/- 0.7; P < 0.05). At follow-up (6.0 +/- 1.5 months), the angiographic restenosis rate was 39% in the angioplasty group and 35% in the stent groups (P = NS). Adverse cardiac events (unstable angina, target lesion revascularization, myocardial infarction, death) occurred in 19% and 18% (P = NS) of the angioplasty and stent patients, respectively. A prospective application of a physiologically guided provisional stent strategy for coronary angioplasty indicated that stent implantation may be required in approximately 50% of patients, an approach that produces similar clinical and angiographic long-term outcomes for stenting and guided angioplasty. These data support a role of coronary physiology as an adjunct in conducting an angioplasty procedure without obligatory stenting.     

Restenosis following placement of an intracoronary heparin treated tantulum stent in the hyperlipidemic miniature swine model

Restenosis persists as an important factor limiting a favorable long term outcome following mechanical revascularization. The objective of the present study was to compare the effects of an intracoronary heparin treated tantalum prototype stent and balloon angioplasty on intimal hyperplasia, luminal diameter, and thrombosis in a porcine restenosis model. Male miniswine maintained on a high cholesterol diet and 325 mg aspirin per day underwent cardiac catheterization and oversized balloon injury to the right and left circumflex coronary arteries. Two weeks later one artery was either balloon injured again or implanted with a stent. No additional anticoagulation following stent placement was given, however aspirin was continued throughout the study. At four weeks, the coronary arteries were harvested and prepared for histologic examination and blinded quantitative morphometric analysis. The prototype stent was successfully deployed in 10 coronary arteries. Histological examination at explant revealed no evidence for thrombus or platelet aggregation. The angiographic luminal diameter of stented vessels was not significantly different from the diameter measured prior to implantation. In contrast, the angiographic diameter of balloon injured vessels was significantly decreased (4.4 +/- 0.4 mm2, balloon injured, vs. 5.8 +/- 3.3 mm2, control; p < 0.05). Stented arteries showed significantly more intimal hyperplasia, compared to balloon injured vessels (2.99 +/- 0.58 mm2 intimal area, stented arteries vs. 0.38 +/- 0.15 mm2 intimal area, control arteries; p < 0.05). In conclusion, heparin treated tantalum wire prototype intracoronary stents were successfully deployed in swine coronary arteries with no evidence for thrombus formation. Despite a significant intimal response, luminal diameter was preserved in stented vessels. The data suggest that a heparin treated tantalum wire prototype intracoronary stent may be an effective method of coronary revascularization that results in the preservation of luminal diameter without thrombotic occlusion.     

Quantitative angiographic comparison of the immediate success of coronary angioplasty, coronary atherectomy and endoluminal stenting

Coronary atherectomy and coronary stenting effectively reduce the severity of coronary artery stenoses, but direct comparisons of these interventions with conventional balloon angioplasty have not been performed. To compare the immediate efficacy of these 3 interventions, the angiographic morphology and the severity of the residual coronary stenosis were quantitatively evaluated in 18 patients undergoing coronary atherectomy and in 21 patients treated by endoluminal coronary stenting. Each of these groups of patients was compared with a matched group of coronary angioplasty patients selected from a large, computerized data-base. The variables matched included patient age and sex, lesions site and severity, and lesion complexity. Both coronary atherectomy and coronary stenting more effectively reduced the severity of the coronary stenosis when compared with balloon angioplasty. The luminal diameter stenosis was reduced from 69 +/- 10 to 22 +/- 20% in the atherectomy group compared with a reduction from 74 +/- 11 to 44 +/- 14% in the matched coronary angioplasty population (p = 0.008). Similarly, the luminal diameter stenosis was reduced from 77 +/- 11 to 26 +/- 12% in the stented group compared with a reduction from 81 +/- 10 to 42 +/- 14% in the matched coronary angioplasty group (p = 0.014). In addition, moderate or severe coronary dissections were noted more frequently in the coronary angioplasty groups than in their respective atherectomy and stent groups (0 vs 33%, p = 0.008, and 5 vs 19%, p = 0.15, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Randomized comparison of coronary stent implantation and balloon angioplasty in the treatment of de novo coronary artery lesions (START): a four-year follow-up.

OBJECTIVE: The purpose of this study was to test the hypothesis that stent implantation in de novo coronary artery lesions would result in lower restenosis rates and better long-term clinical outcomes than balloon angioplasty. BACKGROUND: Placement of an intracoronary stent, as compared with balloon angioplasty, has proven to reduce the rate of restenosis. However, the long-term clinical benefit of stenting over angioplasty has not been assessed in large randomized trials. METHODS: We randomly assigned 452 patients with either stable (129 patients) or unstable (323 patients) angina pectoris to elective stent implantation (229 patients) or standard balloon angioplasty (223 patients). Coronary angiography was performed at baseline, immediately after the procedure and six months later. End points were the rate of restenosis at six months and a composite of death, myocardial infarction (MI) and target vessel revascularization over four years of follow-up. RESULTS: Procedural success rate was achieved in 84% and 95% (balloon angioplasty vs. stent, respectively). The increase in the minimal luminal diameter was greater in the stent group both after the intervention (2.02 +/- 0.6 mm vs. 1.43 +/- 0.6 mm in the angioplasty group; p < 0.0001), and at six-month follow-up (1.98 +/- 0.7 mm vs. 1.63 +/- 0.7 mm; p < 0.001). The corresponding restenosis rates were 22% and 37%, respectively (p < 0.002). After four years, no differences in mortality (2.7% vs. 2.4%) and nonfatal MI (2.2% vs. 2.8%) were found between the stent and the angioplasty groups, respectively. However, the requirement for further revascularization procedures of the target lesions was significantly reduced in the stent group (12% vs. 25% in the angioplasty group; relative risk 0.49, 95% confidence interval 0.32 to 0.75, p = 0.0006); most of the repeat procedures (84%) were carried out within six months of entry into the study. CONCLUSIONS: Patients who received an intracoronary stent showed a lower rate of restenosis than those treated with conventional balloon angioplasty. The benefit of stenting was maintained four years after implantation, as manifested by a significant reduction in the need for repeat revascularization.     

Chlamydia pneumoniae seropositivity predicts the risk of restenosis after percutaneous transluminal coronary angioplasty

This study was done to evaluate whether anti-Chlamydia pneumoniae seropositivity can be a predictor of restenosis after coronary intervention. Recent studies indicate that latent infection with C. pneumoniae is associated with and could possibly cause atherosclerosis. However, it is unknown whether chronic infection with this microorganism is involved in the mechanism of restenosis after percutaneous transluminal coronary angioplasty. We prospectively studied 78 consecutive patients (90 target lesions) with symptomatic coronary artery disease who underwent successful coronary intervention to a de novo lesion (conventional balloon angioplasty to 31 lesions and stent implantation to 59 lesions). At angioplasty, blood samples were collected to measure the serum level of anti-C. pneumoniae IgG to examine whether seropositive patients were prone to restenosis and whether the seropositivity could predict the risk of restenosis determined by follow-up coronary angiography performed within 6 months after the angioplasty. Restenosis, defined as more than 50% stenosis with an increase of 15% or more in the degree of stenosis from that measured on cineangiograms after angioplasty, developed in 36 of 62 seropositive patients and in 4 of 16 seronegative patients (58% vs 25%, P = 0.025). Lesions in the seropositive patients had a greater mean loss index (mean ± SD 0.75 ± 0.45 vs 0.35 ± 0.41, P < 0.001), which was defined as late loss (luminal diameter reduction at follow-up angiography) divided by acute gain (luminal diameter gain by angioplasty), in late loss (1.07 ± 0.64 mm vs 0.65 ± 0.79 mm, P = 0.019), in percentage of diameter stenosis (57% ± 20% vs 41% ± 21%, P = 0.003) and a lesser mean in minimal luminal diameter (1.18 ± 0.58 mm vs 1.67 ± 0.63 mm, P = 0.002) at follow-up angiography. In a multivariate logistic regression model, anti-C. pneumoniae IgG seropositivity was a strong independent predictor of restenosis compared to the other risk factors (odds ratio = 6.2, P = 0.01). C. pneumoniae could play an important role in the mechanism of restenosis and evaluation of the IgG seropositivity, and may help to identify patients at high risk for restenosis. Received: June 13, 2001 / Accepted: December 7, 2001     

Stents covered by an autologous arterial graft in porcine coronary arteries: feasibility, vascular injury and effect on neointimal hyperplasia.

OBJECTIVE: The use of stents has improved results after balloon coronary angioplasty. Several materials have been proposed for covering the metallic surface of the stent to reduce the rate of subacute thrombosis and restenosis. In our institution, an autologous arterial graft was used for covering the external surface of a conventional stent. The angiographic and histological response in a porcine coronary artery model was investigated. METHODS: An autologous arterial graft was removed from the femoral artery and carefully prepared. Subsequently, a conventional stent was covered externally by the arterial graft. Twenty-two covered stents and 22 uncovered regular stents were implanted alternatively in the coronary arteries of 22 pigs. One animal died immediately after the procedure, due to thrombus formation in the uncovered stent. Six animals were sacrificed at seven days and the remaining animals were sacrificed at two months. Before the sacrifice, coronary angiography was performed in all animals. RESULTS: Thrombosis was detected in two control segments and in one covered stented segment. After seven days, the luminal surface of the covered stents was covered by a new endothelial layer in contrast to partial endothelial cell appearance in the control group. The angiographic parameters were similar between the two groups. Histologically, the covered stents were associated with less vascular injury compared to uncovered stents. In covered stents a trend towards reduction of maximal intimal hyperplasia was detected (covered: 116.6 +/- 47.75 vs uncovered: 150.25 +/- 46.81 microns, p = 0.08); also the thickness of the arterial media was reduced (covered: 21.34 +/- 10.28 vs uncovered: 102.63 +/- 18.71 microns, p = 0.02). The luminal and vessel areas were similar in the two groups. CONCLUSIONS: The preparation and implantation of the autologous arterial graft-covered stent is technically safe and feasible. This type of covered stent results in accelerated endothelialization, less vascular injury, thinning of the arterial media and a trend to reduce the intimal hyperplasia in normal coronary arteries.     

Abnormal coronary flow velocity reserve after coronary artery stenting in patients: role of relative coronary reserve to assess potential mechanisms

BACKGROUND: Absolute coronary flow velocity reserve (CVR) after stenting may remain abnormal as a result of several different mechanisms. Relative CVR (rCVR=CVR(target)/CVR(reference)) theoretically normalizes for global microcirculatory disturbances and facilitates interpretation of abnormal CVR. METHODS AND RESULTS: To characterize potential mechanisms of poststent physiology, CVR was measured using a Doppler-tipped angioplasty guidewire in 55 patients before and after angioplasty, after stenting, and in an angiographically normal reference vessel. For the group, the percent diameter stenosis decreased from 75+/-13% to 40+/-18% after angioplasty and to 10+/-9% (all P<0.05) after stent placement. After angioplasty, CVR increased from 1.63+/-0.71 to 1.89+/-0.55 (P<0.05) and after stent placement, to 2.48+/-0.75 (P<0.05 versus pre- and postangioplasty). After angioplasty, rCVR increased from 0.64+/-0.26 to 0.75+/-0.23 and after stent placement to 1.00+/-0.34. In 17 patients with CVR(stent) < or = 2.0, increased basal coronary flow, rather than attenuated hyperemia, was responsible in large part for the lower CVR(stent) compared with patients having CVR(stent) >2.0. In 8 patients with CVR(stent) <2.0, a normal rCVR supported global microvascular disease. The subgroup of 9 patients with CVR(stent) <2.0 and abnormal rCVR (16% of the studied patients) may require a pressure-derived fractional flow reserve to differentiate persistent obstruction from diffuse atherosclerotic disease or microvascular stunning. CONCLUSIONS: Although a majority of patients after stenting normalize CVR for the individual circulation (ie, normal CVR or normal rCVR), in those with impaired CVR(stent), the analysis of coronary flow dynamics suggests several different physiological mechanisms. Additional assessment may be required to fully characterize the physiological result for such patients to exclude remediable luminal abnormalities.     

Myocardial perfusion abnormalities early (12-24 h) after coronary stenting or balloon angioplasty: implications regarding pathophysiology and late clinical outcome

OBJECTIVE: We prospectively examined the prevalence of reversible perfusion defects on very early (12-24 h) thallium-201 single photon emission computed tomography (SPECT) scintigraphy after angiographically successful percutaneous coronary intervention (PCI) by stenting and/or stand-alone balloon angioplasty and the predictive value of these defects for late target lesion revascularization (TLR). PATIENTS AND METHODS: 83 consecutive patients undergoing PCI for 88 lesions (38 balloon angioplasties, 50 stents) underwent very early (12-24 h) SPECT thallium-201 scintigraphy at rest and following administration of 0.7 mg/kg intravenous dipyridamole after PCI. Univariate and multivariate clinical, procedural and scintigraphic correlates of target lesion revascularization during long-term follow-up were examined. RESULTS: Coronary stenting achieved a larger immediate post-PCI minimal luminal dimension (2.7 +/- 0.4 vs. 2.1 +/- 0.4 mm, p < 0.001) and less residual stenosis (4 +/- 12 vs. 19 +/- 11%, p < 0.001) than stand-alone balloon angioplasty. Nonetheless, early reversible perfusion defects were similarly present in the territory supplied by 36% of stented lesions and 32% of lesions treated by balloon angioplasty (NS). Of 81 lesions (76 patients) available for long-term clinical follow-up, TLR was performed in 11% of the stent group and 14% of the balloon angioplasty group (NS). By multivariate logistic regression analysis, diabetes mellitus was the only predictor of late TLR (p < 0.05). The type of intervention (balloon or stent) predicted neither early perfusion defects nor late TLR. CONCLUSIONS: Early 201-thallium SPECT scintigraphy was abnormal in a third of patients treated by stand-alone balloon angioplasty or by stent placement. The very early SPECT scintigraphic findings did not differentiate between balloon and stent and did not predict late TLR.     

Neointimal tissue proliferation after coronary stent implantation without predilatation

INTRODUCTION AND OBJECTIVES: Intravascular ultrasound (IVUS) studies in conventional stent angioplasty with predilatation have demonstrated that late luminal narrowing is caused by neointimal proliferation. In the present study, we analyzed the degree and distribution of in-stent neointimal proliferation after direct stent implantation and aimed to identify variables that predict a proliferative response. MATERIAL AND METHOD: We studied 45 patients who underwent successful stent implantation without predilatation and 23 patients with similar clinical and angiographic characteristics who underwent conventional stent angioplasty with predilatation. IVUS imaging was performed at 7.85+/-2.81 months. The cross-sectional area was measured at five predetermined points in the stented coronary segment. The inflation pressure used in patients who underwent direct stent implantation was higher than that employed in those who underwent conventional angioplasty with predilatation (13+/-3 atm vs 10+/-2 atm; P=.005). RESULTS: Luminal and stent cross-sectional areas were greater in the group that did not undergo predilatation than in the group that did. Neointimal proliferation in the 5 sections analyzed along the axis of the stent was similar in the 2 groups. There was a weak linear relationship between the amount of plaque outside the stent and neointimal proliferation in both the group that underwent predilatation (r=0.37; P=.005) and the group that did not (r=0.33; P=.005). CONCLUSIONS: As with conventional angioplasty, the neointimal proliferation that occurred after direct stent implantation showed a diffuse homogeneous pattern along the length of the stent. There was a weak correlation between this proliferative response and the amount of plaque outside the stent.     

Elastic recoil following percutaneous transluminal coronary angioplasty and Palmaz-Schatz stent implantation

The post-procedural elastic recoil in 133 lesions treated with the Palmaz-Schatz stent was compared to 133 matched lesions treated with balloon angioplasty to determine the role of prevention of elastic recoil in the creation of a larger initial luminal diameter. Elastic recoil was defined as the difference between the maximal diameter of the inflated balloon and the minimal luminal diameter of the dilated segment immediately after the procedure and was evaluated by quantitative coronary angiography. Overdilatation was defined as a dilatation induced by a balloon with a maximal diameter larger than the pre-procedure reference diameter. The percent diameter stenosis was reduced from 73% to 31% in the balloon angioplasty group and from 72% to -4% in the stent group (31% vs. -4%, p < 0.01). Elastic recoil was significantly larger in the balloon angioplasty group than in the stent group (0.94 +/- 0.29 mm vs. 0.09 +/- 0.09 mm, p < 0.01). Overdilatation and lesion morphology had no significant effects on elastic recoil in the stent group. In the balloon angioplasty group, overdilatation, noncalcified lesions and eccentric lesions were associated with increased elastic recoil. These results indicated that the larger post-procedural luminal diameter associated with the Palmaz-Schatz stent was primarily the result of prevention of elastic recoil, which was not influenced by the degree of overdilatation or lesion morphology.     

Six-month Follow-up of Successful Stenting for Acute Dissection After Coronary Angioplasty: Comparison Between Slotted Tube (Palmaz-Schatz) and Flexible Coil (Gianturco-Roubin) Stent Designs

The aim of this study was to evaluate the influence that two different stent designs may have in late outcome following successful coronary stent implantation for acute dissection after balloon angioplasty. In the present study, 50 consecutive patients were matched to compare late outcome between the use of slotted tube (Palmaz-Schatz) and flexible coil (Gianturco-Roubin) stent designs (25 in each group). Group matching was performed according to vessel size, location of target lesion, and dissection type among patients undergoing successful coronary stenting to treat an acute dissection following balloon coronary angioplasty. Poststent minimal luminal diameter (2.46 ± 0.49 mm vs 2.35 ± 0.47 mm, not significant [NS]) and acute luminal gain (2.02 ± 0.61 mm vs 1.85 ± 0.56 mm, NS) were similar in slotted tube and flexible coil stent groups, respectively. However, at 6-month follow-up, late loss in luminal diameter was larger in lesions treated with a flexible coil stent (0.96 ± 0.75 mm vs 0.62 ± 0.55 mm, P = 0.05), and minimal luminal diameter was smaller in those lesions treated with a flexible coil stent (1.38 ± 0.87 mm vs 1.84 ± 0.63 mm, P < 0.05). Angiographic restenosis (> 50% diameter narrowing) occured in four lesions treated with a slotted tube stent (16%) compared to ten lesions treated with a flexible coil stent (40%, P < 0.05). The design of the coronary stent may have significant influence in the late lesion outcome. In patients with acute dissection following balloon coronary angioplasty, use of a slotted tube stent design (Palmaz-Schatz) may result in lower late loss and larger luminal diameter at 6-month follow-up than use of a flexible coil stent design (Gianturco-Roubin).     

Coronary intervention in the diabetic patient: improved outcome following stent implantation compared with balloon angioplasty

BACKGROUND: Diabetic patients undergoing coronary interventional procedures are at increased risk of restenosis and adverse clinical events. The relative impact of stents compared with balloon angioplasty on the outcome of percutaneous intervention in diabetics remains controversial. HYPOTHESIS: The goal of this study was to determine whether stent placement was superior to balloon angioplasty in reducing restenosis of diabetic patients undergoing coronary intervention. METHODS: The STRESS Trial was a prospective randomized comparison of stent placement and balloon angioplasty in the treatment of new native coronary lesions. Of 594 randomized patients. 92 (16%) were diabetic. In this substudy analysis of the STRESS Trial, the outcomes after stenting and balloon angioplasty in diabetic patients were compared. The primary endpoint was restenosis as determined by angiography at 6 months. Clinical outcomes at 1 year were assessed. RESULTS: Procedural success was achieved in 82% of diabetic patients assigned to angioplasty and in 100% assigned to stenting (p < 0.01). Compared with angioplasty, stenting resulted in a larger postprocedural lumen diameter (2.34 +/- 0.44 vs. 1.87 +/- 0.52 mm, p < 0.001) and greater acute luminal gain (1.61 +/- 0.47 vs. 1.06 +/- 0.46 mm, p < 0.001). At 6 months, stenting conferred a larger lumen (1.69 +/- 0.57 vs. 1.38 +/- 0.60 mm, p = 0.03) and greater net luminal gain (0.97 +/- 0.55 vs. 0.52 +/- 0.52 mm, p < 0.001). Restenosis occurred in 60% of the angioplasty group and in 24% of the stent group (p < 0.01). This was accompanied by a lower need for repeat target vessel revascularization after stenting (31 vs. 13%, p < 0.03). CONCLUSIONS: Compared with balloon angioplasty, stent placement in diabetic patients with focal de novo lesions resulted in superior procedural results, reduced restenosis, and improved clinical outcome with fewer repeat revascularization procedures.     

The TRAPIST Study. A multicentre randomized placebo controlled clinical trial of trapidil for prevention of restenosis after coronary stenting, measured by 3-D intravascular ultrasound.

BACKGROUND: Studies have reported benefit of oral therapy with the phosphodiesterase inhibitor, trapidil, in reducing restenosis after coronary angioplasty. Coronary stenting is associated with improved late outcome compared with balloon angioplasty, but significant neointimal hyperplasia still occurs in a considerable proportion of patients. The aim of this study was to investigate the safety and efficacy of trapidil 200 mg in preventing in-stent restenosis. METHODS: Patients with a single native coronary lesion requiring revascularization were randomized to placebo or trapidil at least 1 h before, and continuing for 6 months after, successful implantation of a coronary Wallstent. The primary end-point was in-stent neointimal volume measured by three-dimensional reconstruction of intravascular ultrasound images recorded at the 6 month follow-up catheterization. RESULTS: Of 312 patients randomized at 21 centres in nine countries, 303 (148 trapidil, 155 placebo) underwent successful Wallstent implantation, and 139 patients (90%) in the placebo group and 130 (88%) in the trapidil group had repeat catheterization at 26+/-2 weeks. There was no significant difference between trapidil and placebo-treated patients regarding in-stent neointimal volume (108.6+/- 95.6 mm(3)vs 93.3+/-79.1 mm(3);P=0.16) or % obstruction volume (38+/-18% vs 36+/-21%;P=0.32), in angiographic minimal luminal diameter at follow-up (1.63+/-0.61 mm vs 1.74+/-0.69 mm;P=0.17), restenosis rate (31% vs 24%;P=0.24), cumulative incidence of major adverse cardiac events at 7 months (22% vs 20%;P=0.71) or anginal complaints (30% vs 24%;P=0.29). CONCLUSION: Oral trapidil 600 mg daily for 6 months did not reduce in-stent hyperplasia or improve clinical outcome after successful Wallstent implantation and is not indicated for this purpose.     

Stent or angioplasty after recanalization of chronic coronary occlusions? (The SARECCO Trial).

This study tests whether stent implantation without anticoagulation after catheter recanalization of coronary occlusions can improve outcome compared with balloon angioplasty alone. One hundred ten patients were randomly assigned to angioplasty alone (no stent group) or stent implantation (stent group) after successful recanalization and balloon angioplasty. The type of stent and angioplasty technique utilized were decided by the operator. The acute procedural success in both groups was 100%. The acute minimal lumen diameter (MLD) was 1.85 +/- 0.44 mm in the no stent group versus 2.54 +/- 0.53 mm in the stent group (p <0.01). The diameter stenosis was 21 +/- 13% versus 3 +/- 14% (p <0.01). This was achieved not only by the stent implantation itself but primarily by a larger maximum balloon diameter in the stent group after stent implantation (3.32 +/- 0.55 mm vs 2.86 +/- 0.4 mm, p <0.05). After 4 months, the MLD was 1.15 +/- 0.73 mm in the no stent group versus 1.81 +/- 0.9 mm in the stent group (p <0.01). The diameter stenosis was 56 +/- 29% versus 34 +/- 28% (p <0.01). After 2 years, event-free survival was 26% in the no stent group and 52% in the stent group (p <0.05). Thus, acute and long-term procedural and angiographic success of stent implantation without anticoagulation after recanalization of total coronary occlusions is superior to that of balloon angioplasty alone. This beneficial effect is mainly the result of the larger balloon diameters, which may be used after stent implantation.     

Clinical and angiographic outcome of NIR stent implantation in small vessels with unfavorable lesion morphology

BACKGROUND: Coronary artery stents are used for the treatment of acute or threatened vessel occlusion complicating coronary angioplasty or for the prevention of restenosis after angioplasty. Improvements in stent design made the stenting of complex and small vessels feasible. We prospectively evaluated the safety, efficacy and long-term patency of NIR stent (Boston Scientific, Maple Grove, Minnesota) implantation in small vessels with complex lesion morphology. METHODS: The study population consisted of patients with complex (type OCO) lesions under 3 mm vessel diameter who were undergoing coronary angioplasty for symptomatic coronary artery disease followed by high-pressure NIR stent implantation and antiplatelet therapy only. Follow-up angiography was performed six months after the initial procedure. RESULTS: Of 143 patients fulfilling the angiographic criteria and undergoing stent implantation between October 1995 and November 1997, 67 patients (46.9%) received NIR stents. In 58 patients (86.6%), angiographic 6-month follow-up was available. In one patient (1.7%), stent implantation was unsuccessful. Procedural success of the NIR stent implantation was 98.2%. Implantation of other stents failed in 12 cases. NIR stent implantation was successful in all of them. No patient required urgent bypass surgery. No patient died. Restenosis occurred 5.8 +/- 1.3 months after the initial procedure in 21 patients (36.2%). CONCLUSIONS: Coronary high-pressure stenting of small (< 3 mm) type OCO (AHA/ACC) lesions in patients with symptomatic coronary heart disease is a feasible treatment option with a high procedural success rate and low complication rate. The new flexible NIR stent showed an acceptable restenosis rate. The implantation was successful even in vessels in which previous attempts of Palmaz-Schatz stent placement had failed.     

Angiographic and clinical outcome following paclitaxel-eluting stent (taxus) implantation: a single center experience

Coronary stents dramatically improve acute outcomes of percutaneous coronary interventions but also induce abundant intraluminal neointimal growth. Drug-eluting stents reduce intimal hyperplasia, the main cause of in-stent restenosis. The safety and beneficial effects of paclitaxel-eluting stents (Taxus) in patients treated in daily practice remains to be defined. The aim of this study was to report the late outcomes of Taxus implantation in patients with coronary artery disease. The study population consisted of 151 patients (202 stents) who had undergone coronary Taxus stent implantation between March 2003 and May 2005. Patients were eligible for enrollment if there was symptomatic coronary artery disease or positive functional testing, and angiographic evidence of single or multivessel disease with a target lesion stenosis of 70% in a 2.0 mm vessel. The control coronary angiographies were performed after stent deployment at 12 +/- 2.8 months, and approximately 2 years of follow-up was completed. The polymer-based paclitaxel-eluting stent has been shown to be effective in reducing restenosis. Patients were followed-up for 16.7 +/- 7.4 months. All patients survived after stent implantation, but 2 (1.3%) patients experienced acute myocardial infarction after 3 and 9 months following angioplasty. Recurrent angina pectoris was observed in 3 patients. Angiographic evidence of restenosis was observed in these 5 patients. Three patients underwent angioplasty because of re- stenosis, and coronary artery bypass grafting was conducted in the other 2 patients. The results indicate that Taxus stents can be implanted with a very high success rate and have encouraging long-term angiographic and clinical results.