Eosinophilic infiltration in restenotic tissue following coronary stent implantation

OBJECTIVES: The aim of our study was to compare the histopathological features of restenotic tissue after balloon angioplasty and after stent placement. We emphasized on specific types of inflammatory cells to evaluate the type of tissue immune response in both situations. METHODS: A total of 32 patients underwent elective directional coronary atherectomy; 16 patients had restenosis after balloon angioplasty, 16 patients had in-stent restenosis (ISR). Atherectomy specimens were stained with antibodies against T cells, eosinophils, smooth muscle cell actin, macrophages and with antibodies against T cell activation markers. Quantitative morphometric analysis was performed using image analysis software. RESULTS: In-stent restenotic tissue contained more smooth muscle cells (P < 0.001), anti-CD3 positive T cells (P < 0.001) and eosinophils (P = 0.012). Anti-CD40L positive activated T cells were more numerous in ISR lesions (P = 0.003) and were frequently clustered around stent imprints in the tissue. Five ISR specimens contained grossly visible stent fragments amidst the restenotic tissue. In all cases of balloon restenosis, T cells and eosinophils (if present) were concentrated around lipid rich tissue. CONCLUSIONS: Our study indicates involvement of inflammatory responses in both types of restenosis, with significantly more eosinophils encountered in case of in-stent restenosis. In contrast with clustering of inflammatory cells around stent struts after stent placement, the inflammatory cells in balloon restenosis were located in association with lipid rich tissue, suggesting different inflammatory triggers in balloon restenosis and in-stent restenosis.     

Medial necrosis due to sirolimus-eluting stent implantation in human coronary artery

We report an autopsy case showing medial necrosis at the segment of sirolimus-eluting stent implantation. These findings indicate that cytotoxic effects of sirolimus can induce late-acquired incomplete stent apposition and/or aneurysmal changes after stenting in human coronary arteries.     

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.     

Local heparin delivery prior to coronary stent implantation: Acute and six-month clinical and angiographic results

Stents increase smooth muscle cell proliferation, which may also lead to in-stent restenosis. A local delivery strategy provides higher drug concentration at the angioplasty site and may limit the proliferative response following stenting. Local heparin delivery was attempted in 35 patients following balloon angioplasty using an “over-the-balloon” style catheter (infusion sleeve). The infusion sleeve was successfully tracked and heparin was delivered in 33 (94%) patients. Heparin (1,000 IU/ml) was delivered under low (45 psi, 2 ml, n = 4), intermediate (75 psi, 4 ml, n = 11), and high (100 psi, 4 ml, n = 18) proximal infusion pressures. Stent placement was successful in all cases. Acute and in-hospital complications were a severe arterial spasm after heparin delivery, a non Q-wave myocardial infarction, and two vascular complications. Ten dissections were observed after PTCA and prior to heparin delivery. Of these dissections, 7 remained unchanged, 2 worsened, and 1 improved with local delivery. When heparin was delivered in the absence of dissection, no new dissections were observed. Of the 33 patients who received heparin, 30 (91%) had no symptoms and a negative exercise test at clinical follow-up. QCA analysis of 6-month follow-up angiograms, performed in 32 of 33 (97%) patients, demonstrated an acute gain of 1.98 ± 0.67 mm, a late loss of 0.94 ± 0.78 mm, a net gain of 1.04 ± 0.78 mm, and a loss index of 0.48 ± 0.32. Restenosis (≥50% stenosis) was observed in 4 of 32 (12%) patients. Local delivery of heparin via the infusion sleeve following PTCA and prior to stent deployment is feasible with an acceptable safety profile and a low clinical and angiographic restenosis rate at 6 months. Cathet. Cardiovasc. Diagn. 42:313–320, 1997. © 1997 Wiley-Liss, Inc.     

Multiple stent implantation in single coronary arteries: Acute results and six-month angiographic follow-up

A total of 147 stents were implanted (in overlapping manner in 76% of vessels) in a single coronary artery in 59 patients (60 vessels, 97 lesions, 2.45 stents/vessel) over a period of 18 mo using high pressure stent deployment without ultrasound guidance. The indications for stenting were suboptimal percutaneous transluminal coronary angioplasty (PTCA) result (45%), primary prevention of restenosis (44%), acute closure (10%), and restenosis after plain balloon angioplasty (1%). One patient required emergency coronary artery bypass grafting (CABG) (extensive dissection), and one required early intervention with plain balloon angioplasty and intracoronary urokinase for stent thrombosis. There were no deaths. Thirteen patients had recurrence of angina within 6 mo and angiograms were performed in all. These showed intrastent restenosis in nine (all had successful repeat plain balloon angioplasty), development of new disease in other vessels along with restenosis close to the stent in the target vessel in one (underwent elective CABG) and normal angiograms with widely patent stents in three. Forty-five patients (77%) remained free of recurrent angina and 25 of these had follow-up angiograms (56%) at a mean of 172 days, two showing restenosis. Thus, the restenosis rate per patient in the symptomatic group (angiographic follow-up in 100%) was 77% and in the asymptomatic group (angiographic follow-up in 56%) was 8%. The restenosis rate in the subgroup with bailout stenting (n = 6) was 20% (angiographic follow-up in 83%). The overall restenosis rate per patient was 32% (overall angiographic follow-up in 66%). During the 6-mo follow-up period, one patient underwent elective CABG (1.7%), one sustained a non-Q myocardial infarction (1.7%), nine had repeat PTCA to the target vessel (15.5%), and there were no deaths. The event-free survival rate was 77%. Multiple stent implantation aided by high pressure stent deployment without ultrasound guidance and with adjunctive optimal antiplatelet therapy without oral anticoagulation seems to be a useful and effective revascularisation strategy to deal with long lesions and acute dissections with a high procedural success rate. The restenosis rate is acceptable and is not appreciably high as reported in previous studies from the “warfarin era.” Cathet. Cardiovasc. Diagn. 42:158–165, 1997. © 1997 Wiley-Liss, Inc.     

Acute exacerbation of chronic interstitial pneumonia: high-resolution computed tomography and pathologic findings

PURPOSE: To review the high-resolution computed tomography (CT) and histologic findings of acute exacerbation of chronic interstitial pneumonia and to assess the potential value of CT and histologic findings in predicting prognosis. MATERIALS AND METHODS: The study included 24 patients with clinical and histologic diagnosis of acute exacerbation of chronic interstitial pneumonia who underwent CT within 1 month before biopsy or autopsy. The final diagnosis was acute exacerbation of idiopathic pulmonary fibrosis (n=12), usual interstitial pneumonia associated with connective tissue disorders (n=5), idiopathic nonspecific interstitial pneumonia (n=4), and nonspecific interstitial pneumonia associated with connective tissue disorders (n=3). RESULTS: The main CT findings consisted of bilateral ground-glass opacities (100%) and consolidation (71%) superimposed on a reticular pattern. The ground-glass opacities and/or consolidation were diffuse in 54% of the cases, multifocal in 21%, and peripheral in 25%. The histologic patterns of acute injury consisted of diffuse alveolar damage (n=20), acute organizing pneumonia (OP) (n=3), and extensive fibroblastic foci (n=1). Eight (33%) patients survived the acute episode, including all 3 patients with OP and the patient with extensive fibroblastic foci (P=0.01). The survivors included 3 of 13 (23%) patients with diffuse parenchymal opacification, 2 of 5 (40%) patients with multifocal, and 3 of 6 (50%) patients with peripheral opacification on CT. CONCLUSIONS: The CT findings of acute exacerbation of chronic interstitial pneumonia consist of diffuse, multifocal, or peripheral parenchymal opacification superimposed on reticulation. Histologic findings of OP are superior to CT in predicting prognosis.     

Acute and intermediate clinical and angiography results after coronary stent implantation]

The value of stenting in emergency situations in interventional angioplasty procedures is widely accepted. Stenting remains controversial as a therapeutic method for use beyond the acute phase, as the results reported in the acute phase are characterized by a wide range. This study reports the implantation results of Palmaz-Schatz stents in 64 cases mostly for failed PTCA. Stents were mounted on Monorail-PVC-balloon catheters. The acute success rate was 96.8%. In two cases with stent misplacement CABG was performed within 48 h. No lethal events occurred in the acute phase. Stent thrombosis has only been seen in four cases (6.5%) so far under subtle monitoring of the anticoagulant regime. Restenosis rate (definition: NHLBI-4) according to serial angiography 6 and 12 weeks after implantation was 4.25% at 6 weeks, with a cumulative rate of 19.4% up to 12 weeks. All recurrences eligible for PTCA have been successfully redilated. A high extracardiac complication rate--predominantly groin hematoma--is the main disadvantage of the procedure. Surgical repair was necessary in 11.4% up to 6 weeks after implantation. Surprisingly high was also the incidence of hematuria, also in 11.4%, in the phase of high anticoagulation. In conclusion, stenting is an effective therapeutic method to avoid emergency CABG and elective CABG in most cases of failed PTCA.     

Low response to clopidogrel is associated with cardiovascular outcome after coronary stent implantation.

AIMS: To assess whether low response to clopidogrel influences cardiovascular outcome after coronary stent implantation in a consecutively measured cohort of patients with coronary stent implantation. METHODS AND RESULTS: A total of 379 consecutive patients with symptomatic coronary artery disease (CAD), (stable angina n = 206 and acute coronary syndrome, n = 173) treated with percutaneous coronary stenting were enrolled in this trial. Responsiveness to clopidogrel was assessed by ADP (20 micromol/L)-induced aggregometry at least 6 h (mean 34.8+/-25.9 h) after administration of a loading dose of 600 mg clopidogrel. Platelet inhibition < 30% was defined as low response to clopidogrel. At 3-month follow-up, the primary outcome of a combined major cardiovascular event including non-fatal myocardial infarction, non-fatal ischaemic stroke, or cardiovascular death was evaluated. Twenty-two patients (5.8%) were classified as low responders. Compared with patients who adequately responded to clopidogrel, a low responder had a significantly higher risk of major cardiovascular events [22.7 vs. 5.6%; odds ratio, 4.9; 95% confidence interval (CI), 1.66-14.96; P = 0.004]. After adjustment for other factors influencing cardiovascular outcome, low response to clopidogrel and severe left ventricular dysfunction were independently associated with a major cardiovascular event within 3 months (hazard ratio for low response to clopidogrel, 3.71; 95% CI, 1.08-12.69; P = 0.037). CONCLUSION: Low response to clopidogrel in patients with symptomatic CAD treated by stenting significantly enhances the occurrence of cardiovascular events and death. The evaluation of low response to clopidogrel may help to identify patients at increased risk who may benefit from intensified antiplatelet strategy.     

Simultaneous drug-eluting and bare-metal stent implantation: long-term clinical outcome and findings of clinically indicated coronary angiography

Background:

Simultaneous drug‐eluting stent (DES) and bare‐metal stent (BMS) implantation is occasionally employed in clinical practice, but its long‐term clinical and angiographic outcome is not clear.

Hypothesis:

We aimed to describe the long‐term clinical outcome and the findings of clinically indicated coronary angiography in patients subjected to simultaneous DES and BMS implantation (“hybrid stenting”).

Methods:

We identified 236 patients (mean age 62.9 ± 11.4 years, 76.7% men) who had undergone percutaneous coronary intervention with at least 1 DES and 1 BMS. At a median follow‐up of 42 months (range, 6–89 months) available in 222 patients, 13 (5.9%) patients died from cardiac causes, 13 (5.9%) experienced nonfatal acute myocardial infarction, and 24 (10.8%) experienced unstable angina. Clinically indicated repeat coronary angiography was performed in 64 patients (28.8%).

Results:

Thirty‐one patients (14%) had target lesion revascularization (TLR). The DES demonstrated lower TLR rates (15.9% vs 36.9%, P = 0.002) and lower late loss (0.44 ± 0.5 mm vs 0.68 ± 0.7 mm, P = 0.009) compared with BMS. Use of DES was independently associated with lower risk for binary restenosis (hazard ratio [HR]: 0.41, 95% confidence interval [CI]: 0.19–0.89, P = 0.03) and TLR (HR: 0.26, 95% CI: 0.12–0.54, P<0.001).

Conclusions:

Although a hybrid stenting strategy demonstrates a reasonable long‐term prognosis even in high‐risk patients, DES have a better angiographic outcome compared with BMS under the influence of common patient‐related restenosis risk factors. © 2011 Wiley Periodicals, Inc. The authors have no funding, financial relationships, or conflicts of interest to disclose.     

Direct stent implantation in acute coronary syndrome

OBJECTIVE: To evaluate the feasibility and safety of direct stenting and to compare it with conventional implantation techniques in patients with acute coronary syndrome (ACS). METHODS: A total of 145 patients were divided into two arms based on the stenting technique used: group I (n = 71) = direct stenting without predilatation group that included only single-vessel procedures and group II (n = 74) = stenting with predilatation group that included only single-vessel conventional stent implantations. The primary endpoint of the study was the major adverse clinical event (MACE) rate in-hospital, at 1 month, and at 6 months and the secondary endpoint was the balloon inflation time (BIT), the number of balloon inflations (NBI), the radiation exposure time (RET), the amount of contrast dye used (ACD) and the no-reflow phenomenon. RESULTS: Primary success rate was 89% in group I and 95% in group II; overall procedural success rate was 94% in group I and 100% in group II. The rate of MACE was not different during the follow-up period between the two groups. The RET, BIT and NBI were significantly lower in group I than in group II (p < 0.001 for all). The ACD used was also significantly lower in group I than in group II (125 60 ml versus 155 71 ml; p = 0.006). Furthermore, the rate of no-reflow was significantly lower in group I than in group II (2.8% versus 13.5%; p = 0.03). CONCLUSION: Direct stenting is a feasible and safe technique. It is equivalent to single-vessel conventional stent implantation techniques with respect to MACE rate in-hospital, at 1 month, and at 6 month follow-up in selected patients with ACS.     

Balloon dilatation and coronary vascular stent implantation

To avoid acute complications and restenosis after percutaneous transluminal coronary angioplasty coronary stents were developed. For the first time three flexible Palmaz-Schatz stents were implanted after application and fixation by balloon inflation in two patients with severe lesions of the left anterior descending coronary artery. The vessels showed larger diameters with smoother surface and smaller gradients compared to balloon angioplasty as related to a blockade of the elastic properties of the vessel and suggested fixation of intima or media dissection. The implantation of the coronary stents was without complications. The control after 24 h showed an open vessel with unchanged diameter. The patients with the proximal lesion of the left anterior descending coronary artery six months later showed no restenosis and no luminal narrowing. The recanalized left anterior descending coronary artery, which was dilated, received two stents and was reoccluded after six months. Meanwhile, up to four stents were implanted successfully in an additional four patients with open vessels as the 24-h-control. Based on this and previous work the implantation of coronary stents seems to open a new dimension for percutaneous transluminal coronary angioplasty because vessel occlusions can be prevented. Whether or not the restenosis rate can be reduced has to be demonstrated in additional studies.     

Preinterventional peak monocyte count and in-stent intimal hyperplasia after coronary stent implantation in human coronary arteries

BACKGROUND: The mechanism of restenosis after stent implantation principally is neointimal hyperplasia. There is evidence that monocytes play a important role in in-stent restenosis (ISR) after stent implantation. Hypothesis: This study assessed the relationship between preinterventional peak monocyte count and neointimal growth after successful stent implantation. METHODS: We performed coronary stent implantation in 85 patients (85 de novo lesions). Peripheral blood sample was obtained in all patients every 12 h before coronary angiography for measurement of peripheral monocytes. All patients received angiographic and intravascular ultrasound (IVUS) follow-up at 6 months after stenting. RESULTS: The preinterventional circulating monocyte count was significantly higher in the ISR group than that in the group without ISR (654 +/- 62/vs. 461 +/- 222/mm3, p < 0.001) and was significantly higher in the reintervention group than that in the no-reintervention group (660 +/- 72/ vs. 470 +/- 216/mm3, p< 0.001). The incidence of ISR and repeat intervention associated with preinterventional monocyte count was highest among the patients in the highest tertile, who were at a 2.64-fold increased risk of ISR and 3.22-fold increased risk of repeat intervention compared with the patients in the lowest tertile. A significant positive correlation was found between preinterventional peak monocyte count and preinterventional plaque and media cross-sectional area and follow-up neointima area (r = 0.311, p = 0.007, r = 0.465, p < 0.001, respectively). The neointima area associated with preinterventional monocyte count was largest among the patients in the highest tertile, that is, 2-fold larger than that of the patients in the lowest tertile (p < 0.001) and 1.44-fold larger than that of the patients in the middle tertile (p = 0.001). CONCLUSION: Our results suggest that circulating preinterventional monocytes play a principal role in the process of in-stent neointimal growth after successful stent implantation.     

Adenosine‐induced temporary block to improve accuracy of ostial coronary stent implantation: Adenosine to improve stent implantation accuracy

Implantation of coronary stents should be performed with high precision to ensure optimal clinical results. In some clinical conditions, during the cardiac cycle, significant movement of the predeployed stent may impact its implantation accuracy. We describe a case in which a patient had a short ostial left anterior descending artery stenosis and hyperkinetic left ventricle, resulting in significant movement of the stent inside the vessel lumen during the cardiac cycle. Intracoronary adenosine was used to create temporary heart block to enable accurate stent implantation.© 2013 Wiley Periodicals, Inc.