Palmaz-Schatz stent embolization: long-term clinical and angiographic follow-up

A long-term clinical and angiographic follow-up of a case of peripheral coronary stent embolization is reported. No clinical sequelae occurred in the immediate and long-term (five years) followup. The five-year follow-up angiographic images provided visual documentation of absence of stent-associated stenosis. This case highlights the concept that fibro-intimal hyperplasia may not occur when plaque and balloon trauma are absent at the site of stent embolization.     

Restenosis following percutaneous transluminal angioplasty: clinical,physiologic and pathological features.

Percutaneous transluminal coronary angioplasty (PTCA) has been used clinically for 8 years and is becoming widely accepted in the treatment of atherosclerotic coronary artery disease. Since the long-term effects of the procedure are unknown, the rate of restenosis following the procedure, approximately 30%, is of major concern. We briefly review the current status of PTCA and the effect of angioplasty on the vessel wall and discuss proposed mechanisms of recurrent stenosis.     

Increase in plasma digitalis-like activity during percutaneous transluminal coronary angioplasty in patients with coronary stenosis

Despite the fact that numerous studies have been published regarding the possible presence in plasma of an endogenous Na-K pump inhibitor with a digitalis-like structure in essential hypertension, very little is known about this factor in heart disease in general, and in situations characterized by low cardiac output. We measured the ability of plasma obtained from the femoral vein to inhibit a human renal Na(+)-K+ ATPase before and immediately after percutaneous transluminal coronary angioplasty (PTCA) in 6 patients suffering from angina pectoris and severe coronary stenosis. Intraerythrocyte sodium and potassium concentrations were also measured simultaneously. Na(+)-K+ ATPase inhibition proved significantly greater after angioplasty as compared to basal activity (percentage inhibition: 31.5 +/- 7.8 vs 16.1 +/- 12.2). No significant changes in intraerythrocyte sodium and potassium were detected. Though we are not in a position to define the mechanism underlying the increase in the digitalis-like factor, a plausible hypothesis may be that the reduction in cardiac output during PTCA by raising cardiac pressures may stimulate the production of a factor of compensatory inotropic significance.     

Long-term clinical outcome after stent implantation in coronary arteries

The long-term clinical outcome after planned and unplanned stent implantation was assessed in a single-center, observational study in 178 patients who underwent coronary stent implantation between November 1986 and July 1994. Main outcome measures were survival and event-free survival at 5 years (Kaplan-Meier method). Independent predictors for event-free survival were determined by using multivariate logistic regression analysis. Patients underwent planned (group 1, n 3 101) or unplanned (group 2, n 3 77) stent implantation. During the in-hospital period, there were no deaths. The incidence of Q-wave and non-Q-wave acute myocardial infarction (AMI), coronary artery bypass graft (CABG) and repeat percutaneous transluminal coronary angioplasty (PTCA) was 5.0%, 2.0% and 4.0%, respectively, in group 1, versus 32.5%, 23.4% and 10.4%, respectively, in group 2. During the follow-up period (median 4.0 years, range 0.29-9.8 years), the incidence of death, AMI, and repeat revascularization (CABG and PTCA) was 5.9%, 8.9% and 40.6%, respectively, in group 1, versus 1.3%, 5.2% and 36.4%, respectively, in group 2. Survival and event-free survival at 5 years was 73 (7%) and 47 (7%), respectively, for patients who underwent planned stent implantation. It was 98 (0.1%) and 34 (6%), respectively, for patients who underwent unplanned stent implantation. At the end of follow-up, 31.9% of patients had angina pectoris class III or IV (Canadian Cardiovascular Society). The long-term clinical outcome after both planned and unplanned stent implantation was characterized by a high incidence of repeat revascularization. It is conceivable that changes in stent design and implantation techniques, in addition to novel therapeutic approaches addressing neointima formation and progression of atherosclerosis, may improve the long-term clinical outcome.     

Safety of intracoronary administration of c-myc antisense oligomers after percutaneous transluminal coronary angioplasty (PTCA)

We wished to assess the clinical safety and pharmacokinetics of ascending doses of a synthetic oligodeoxynucleotide (LR-3280) administered after coronary angioplasty. Antisense oligodeoxynucleotides designed to hybridize with target messenger ribonucleic acid (mRNA) in a complementary fashion to inhibit the expression of corresponding protein also have the ability to bind to extracellular growth factors. LR-3280 has been shown to reduce c-myc expression, inhibit growth and collagen biosynthesis in human vascular cells, and reduce neointimal formation in animal models of vascular injury. After successful percutaneous transluminal coronary angioplasty (PTCA), 78 patients were randomized to receive either standard care (n = 26) or standard care and escalating doses of LR-3280 (n = 52) (doses from 1 to 24 mg), administered into target vessel through a guiding catheter. Overall safety was evaluated by clinical adverse events, laboratory tests, and electrocardiograms. Patency was evaluated by quantitative coronary angiography. There were no clinically significant differences between treated and control patients. No adverse effects of LR-3280 on the patency of dilated coronary arteries were observed. Pharmacokinetic data revealed that peak plasma concentrations of LR-3280 occurred at 1 minute over the studied dose range and rapidly decreased after approximately1 hour, with little LR-3280 detected in the urine between 0-6 hours and 12-24 hours. The intracoronary administration of LR-3280 is well tolerated at doses up to 24 mg and produces no adverse effects in dilated coronary arteries. These results provide the basis for the evaluation of local delivery of this phosphorothioate oligodeoxynucleotide for the prevention of human vasculoproliferative disease.     

Management of acute coronary occlusion during percutaneous transluminal coronary angioplasty: experience of complications in a hospital without on site facilities for cardiac surgery.

OBJECTIVE--To determine whether percutaneous transluminal coronary angioplasty may be safely performed in cardiology centres in the United Kingdom without immediate on site cardiac surgical cover for complications arising at angioplasty. DESIGN--Retrospective review of coronary angioplasties and complications in a hospital without on site cardiac surgical cover. SETTING--All angioplasties were performed in the catheterisation laboratory of the Belfast City Hospital. Revascularisation surgery for complicated coronary angioplasty was performed in the cardiac surgical unit of the Royal Victoria Hospital, 2.4 km away from the catheterisation laboratory. PATIENTS--540 Coronary angioplasties were performed on 512 patients between late 1982 and November 1988. Indications included stable angina, unstable rest angina, and suitable coronary disease at coronary arteriography after myocardial infarction. MAIN OUTCOME MEASURES--In hospital mortality after complicated coronary angioplasty and delay to surgical revascularisation after acute coronary occlusion at angioplasty. RESULTS--Coronary angioplasty was successful in 444 cases (82%). Acute coronary occlusion occurred in 35 cases (6.5%). Twelve patients required urgent revascularisation surgery and were transferred safely to the surgical unit; none of these patients died. A mean delay of 268 minutes (range 180-390 minutes) occurred before revascularisation compared with 273 minutes (range 108-420 minutes) in the Royal Victoria Hospital, where on site surgical cover was available. The principal cause of delay was the wait for a cardiac operating theatre to become available and not the transfer time between hospitals. Five deaths occurred after coronary angioplasty, a mortality of 0.9%. Three deaths were related to acute coronary occlusion. The absence of immediate surgical help did not influence the outcome in any patient. CONCLUSION--With careful selection of patients coronary angioplasty may be safely performed in a hospital without on site cardiac surgical facilities, provided that these are available at a nearby centre.     

经皮腔内冠状动脉成形术中缺血预适应对C反应蛋白、肌钙蛋白I的影响

目的:通过测定常规经皮冠状动脉血管成形术及支架植入术(PCI)组及缺血预适应处理组术前、术后患者肌钙蛋白I(CTnI)、C-反应蛋白(CRP)的变化,以探讨缺血预适应对术中心肌缺血耐受程度及术后cTnI、CRP的影响.方法:首先设定缺血预适应(IP)方案,观察IP组患者51例、常规PCI组(CP组)患者53例术后CRP、CTnI、SvO2的变化以及术中不良事件发生与否.结果:IP组术前、术后C-反应蛋白(CRP)、肌钙蛋白I(CTnI)的变化程度低于CP组,存在显著性差异(P<0.05).IP组术中发生心绞痛及ECG ST段缺血型改变的几率低于常规PCI组,存在显著性差异(P<0.05).结论:缺血预适应方案可以作为PCI操作的常规方法,它可以减轻介入操作对心肌细胞的损伤,降低冠脉介入术中、术后的不良事件的发生.     

Intravascular ultrasound imaging of myocardial-infarction-related arteries after percutaneous transluminal coronary angioplasty reveals significant plaque burden and compensatory enlargement

We studied patients with acute myocardial infarction (MI) by intravascular ultrasound (IVUS) to elucidate the controversy as to the amount and severity of the atherosclerotic disease at the culprit lesion site in acute MI, as discrepancies exist between angiographic and pathological reports. Twenty-five consecutive patients (age 56 3 10.5 years), with acute MI, underwent IVUS study of the MI-related artery immediately following successful PTCA to the culprit lesion. The IVUS images were analyzed quantitatively and qualitatively and were compared with the angiography of the same arteries. At the PTCA site, 64% of the lesions had an area stenosis of 50-70% and the plaque cross-sectional area (CSA) averaged 0.5 3 0.18 of the arterial CSA. IVUS-defined atherosclerosis was found also in 72% of the segments proximal and distal to the culprit lesion with a plaque/artery CSA ratio of 0.25 3 0.2. The angiogram revealed only 30% of these segments to be abnormal (P 3 0.001). Sixty-nine per cent of all the plaques were defined as 'soft' (low echo-genecity) versus 31% 'hard' (high echo-genecity). The hard plaques were larger than the soft plaques (0.5 3 1.6 versus 0.37 3 0.19 CSA index, respectively, P 3 0.01). With the increase in plaque area there was a significant increase in arterial cross-sectional area. This was demonstrated for all the diseased segments with a correlation coefficient of 0.49 (P 3 0.0001) and for the diseased reference sites a similar correlation coefficient of 0.49 (P 3 0.003) was found. Contrary to coronary angiographic-based reports, this IVUS study revealed a significant atheromatous plaque burden at the culprit lesion of MI-related arteries as well as diffuse atherosclerosis in the reference segments proximal and distal to the lesion. The detection of compensatory enlargement may explain the discrepancies between the histopathological and the angiographic studies.     

Coronary stent implantation throughout technical evolution: immediate and follow-up results

Coronary stenting (stent implantation) has evolved over the last 5 years with changes in stent design, stent material and the implantation technique. The use of high-pressure balloon inflation (HP), intravascular ultrasound (IVUS) and appropriate antiplatelet therapy have contributed to the abolishment of the need for subsequent anticoagulation, allowing extended stent applications. We compared results in three groups of patients having stent implantation throughout the period of evolution: group A: no IVUS, no HP, with subsequent anticoagulation treatment (n 3 434); group B: no IVUS, yes HP, without subsequent anticoagulation treatment (n 3 192); and group C: yes IVUS, yes HP, without subsequent anticoagulation treatment (n 3 588). The primary success rates were comparable in all groups. There was a clear change in indications for stenting in groups B and C compared with group A (elective stenting: group A 3 32%; group B 3 66%; group C 3 69%; P < 0.0001), in reference vessel size (group A 3 3.22 3 0.37 mm; group B 3 2.92 3 0.56 mm; group C 3 2.98 3 0.57 mm; P < 0.0001), and for presence of type B2 and C lesions (group A 3 57%; group B 3 72%; group C 3 74%; P < 0.001). The complication rate significantly decreased in group C (group A 3 3.6%; group B 3 4.1%; group C 3 1.2%; P < 0.001) and the mean patient hospital stay decreased to 2 days in groups B and C due to the abolition of the need for anticoagulant treatment. The angiographic restenosis rate increased in groups B and C (group A 3 20%; group B 3 34%; group C 3 32%; P < 0.001). The need for a repeat procedure increased as stenting of more complex lesions and smaller vessels was attempted: target lesion revascularization (TLR) was performed in 16% of patients in group A (73/434), in 18% of group B (35/192) and in 22% of group C (129/588) (P 3 0.04 for A versus C). Major cardiac events (MACE) occurred in 142 patients in group A (33%), 60 patients in group B (31%) and in 181 patients in group C (30%). The evolving technique of coronary stenting has expanded the spectrum of indications and range of coronary vessels attempted, and decreased the complication rates and hospital stay. However, in less-favorable subsets, additional improvements are needed to affect the long-term outcome.     

Immediate and long-term outcomes of coronary stenting in relation to stent implantation pressure in patients with coronary heart disease

The paper evaluates the pressure impact of implantation of intracoronary stents of different designs on the immediate and long-term outcomes of stenting. A retrospective study included 192 patients. Matrix and wire stents were implanted in 97 (50.5%) and 95 (49.5%) patients, respectively. In one part of the patients, the coronary stent was implanted under nominal pressure, in the other, the stent after implantation was extended with a balloon by using high pressure. Good immediate angiographic and clinical results were obtained in all 192 patients. Thirty three (17.2%) patients were found to have coronary spasm at the site of a stent. There was no significant difference in the development of coronary spasm, which was associated with the type of an implanted (matrix or wire) stent and with the pattern of its implantation (under high or nominal pressure). Dissection along the stent edges developed in 17 of the 192 patients, which amounted to 8.8%. It significantly more frequently developed in patients from Subgroup IA than in those from Subgroup IB. There was no significant difference in the development of restenosis in patients after implantation of matrix or wire stents and in the relation to the stent implantation pressure.     

Immediate and long-term results of coronary stent implantation without predilatation (direct stenting) in patients with coronary heart disease

The paper assesses the immediate and long-term results of direct stenting (without the stage of predilation) and compares with the outcomes of conventional stent implantation. A prospective study included 183 patients. All the patients were divided into two groups according to the procedure of stent implantation. In 85 (46.7%) patients, the stent was implanted without preliminary predilation of stenosis (direct stenting). These patients formed Group 1. Group 2 comprised 97 (53.3%) patients in whom the stent was placed by using the routine procedure. All the patients enrolled into the study had types A, B1, and B2 stenoses according to the ACC/AHA classification and received the conventional antiaggregatory and anticoagulant therapy. The technical success of direct stenting was 97.7%. There were no cases of stent dislocation and loss during direct stenting or expansion of a balloon and stent. Analyzing the immediate results in all the patients of the both groups showed a positive angiographic success. Thus, a primary angiographic and clinical success of direct stenting was achieved in all (100%) patients. Recurrent angina pectoris with restenosis was observed in 8 (9.4%) patients in Group 1 and in 21 (21.6%) in Group 2 (p < 0.05). Direct stenting significantly differs from the routine stent implantation in all procedure parameters. Thus, direct stenting in patients with uncomplicated stenoses is a safe and feasible procedure.     

Initial results and long-term clinical follow-up of an amorphous hydrogenated silicon-carbide-coated stent in daily practice

The hemocompatibility and biocompatibility of a stent are determined by the physical and electrochemical properties of the stent surface. The aim of this study was to determine the feasibility, safety and efficacy of implantation of a stent coated with silicon carbide. Baseline characteristics were collected prospectively. The occurrence of cardiac adverse events and the angina score were assessed at clinical follow-up. A total of 193 Tensum stents were implanted in 174 patients. In hospital, one patient experienced stent thrombosis and in 6% of the patients a creatinine kinase elevation to 240 U/l or more occurred. Long-term follow-up was performed in 172 patients, with a mean follow-up of 454 +/- 181 days. Ninety-seven per cent were still alive, 15% had undergone target-vessel revascularization, and 2% had angiographic restenosis and were treated with medication only. Seventy-one per cent of the patients were free of anginal complaints, and 20% had anginal complaints in Canadian Cardiac Society class I or II. The Tensum coronary stent showed to be a safe and efficacious device in this study, with a high primary success rate and favorable long-term clinical followup.     

Local hemodynamic analysis after coronary stent implantation based on Euler-Lagrange method

Coronary stents are deployed to treat the coronary artery disease (CAD) by reopening stenotic regions in arteries to restore blood flow, but the risk of the in-stent restenosis (ISR) is high after stent implantation. One of the reasons is that stent implantation induces changes in local hemodynamic environment, so it is of vital importance to study the blood flow in stented arteries. Based on regarding the red blood cell (RBC) as a rigid solid particle and regarding the blood (including RBCs and plasma) as particle suspensions, a non-Newtonian particle suspensions model is proposed to simulate the realistic blood flow in this work. It considers the blood’s flow pattern and non-Newtonian characteristic, the blood cell-cell interactions, and the additional effects owing to the bi-concave shape and rotation of the RBC. Then, it is compared with other four common hemodynamic models (Newtonian single-phase flow model, Newtonian Eulerian two-phase flow model, non-Newtonian single-phase flow model, non-Newtonian Eulerian two-phase flow model), and the comparison results indicate that the models with the non-Newtonian characteristic are more suitable to describe the realistic blood flow. Afterwards, based on the non-Newtonian particle suspensions model, the local hemodynamic environment in stented arteries is investigated. The result shows that the stent strut protrusion into the flow stream would be likely to produce the flow stagnation zone. And the stent implantation can make the pressure gradient distribution uneven. Besides, the wall shear stress (WSS) of the region adjacent to every stent strut is lower than 0.5 Pa, and along the flow direction, the low-WSS zone near the strut behind is larger than that near the front strut. What’s more, in the regions near the struts in the proximal of the stent, the RBC particle stagnation zone is easy to be formed, and the erosion and deposition of RBCs are prone to occur. These hemodynamic analyses illustrate that the risk of ISR is high in the regions adjacent to the struts in the proximal and the distal ends of the stent when compared with struts in other positions of the stent. So the research can provide a suggestion on the stent design, which indicates that the strut structure in these positions of a stent should be optimized further.

     

Blood pressure response to percutaneous transluminal angioplasty for renovascular hypertension: an overview of published series.

OBJECTIVE--To evaluate the efficacy and safety of transluminal angioplasty in the treatment of renovascular hypertension. DESIGN--Overview of 10 published case series. SETTING--Mostly tertiary referral centres. PATIENTS--691 Patients treated by angioplasty for renovascular hypertension, 464 for atherosclerotic stenosis, 193 for fibromuscular stenosis, and the remainder mainly for post-transplant stenosis. The inclusion criteria varied considerably between studies. INTERVENTIONS--Percutaneous transluminal renal artery angioplasty (successful or attempted); prophylaxis against restenosis in most cases. Policies on antihypertensive drug treatment and follow up varied. MAIN OUTCOME MEASURES--Blood pressure response as defined in the individual papers, with each patient classified as either cured, improved, or failed. Each study used a different definition of improvement in blood pressure. Complication rates. RESULTS--Follow up data were available for 670 patients. The procedure was technically successful in 611 patients (88%). The overall cure rate for hypertension was 24% (163 patients) and a further 43% (286) were "improved." There were large and significant variations between studies in the rate of technical success and also the blood pressure outcome. In each series patients with fibromuscular lesions, had a higher cure rate than those with atherosclerotic lesions (overall cure 50% v 19% odds ratio 3.9, 95% confidence interval 2.6 to 6.0). Complications were reported in 63 (9%) patients and three patients died (0.4%). CONCLUSIONS--The evidence for the value of angioplasty in treating renovascular hypertension has serious limitations. Angioplasty for fibromuscular disease seems to be worth while, but for atherosclerotic lesions the benefit appears to be small and its efficacy needs to be compared with medical therapy in randomised trials. These findings emphasise the importance of early formal evaluation of new therapeutic techniques.