Intracoronary Stent Placement Research Articles

Spontaneous Coronary Artery Dissection in a Pregnant Woman

In Brief BACKGROUND Spontaneous coronary dissection is a rare condition occurring more often in women, with a higher frequency during the peripartum period. No specific etiology has been defined to describe this uncommon, yet often fatal phenomenon. CASE A young woman presented at 36 weeks of a noncomplicated pregnancy with recent onset of diaphoresis, dyspnea, and tingling substernal chest discomfort. Upon evaluation, she developed cardiovascular collapse and ventricular fibrillation requiring aggressive resuscitative measures, eventually leading to extracorporeal membrane oxygenation. Right coronary artery dissection was ultimately diagnosed and treated with intracoronary angioplasty and stent placement. CONCLUSION Spontaneous coronary dissection must be considered when evaluating a patient with a similar clinical presentation, given its overall mortality of more than 50% at presentation, particularly in the peripartum period. We describe a case of spontaneous coronary artery dissection in a peripartum woman requiring extracorporeal membrane oxygenation and intracoronary stent placement.

Spontaneous coronary artery dissection in a pregnant woman

BACKGROUND: Spontaneous coronary dissection is a rare condition occurring more often in women, with a higher frequency during the peripartum period. No specific etiology has been defined to describe this uncommon, yet often fatal phenomenon. CASE: A young woman presented at 36 weeks of a noncomplicated pregnancy with recent onset of diaphoresis, dyspnea, and tingling substernal chest discomfort. Upon evaluation, she developed cardiovascular collapse and ventricular fibrillation requiring aggressive resuscitative measures, eventually leading to extracorporeal membrane oxygenation. Right coronary artery dissection was ultimately diagnosed and treated with intracoronary angioplasty and stent placement. CONCLUSION: Spontaneous coronary dissection must be considered when evaluating a patient with a similar clinical presentation, given its overall mortality of more than 50% at presentation, particularly in the peripartum period.

Cilostazol for prevention of thrombosis and restenosis after intracoronary stenting.

To evaluate the potential use of cilostazol in intracoronary stenting. Clinical literature was accessed through MEDLINE (1966-March 2001). Key search terms included cilostazol, intracoronary stenting, and coronary angioplasty. Abstracts of clinical trials presented at major cardiology professional association meetings were also reviewed. Intracoronary stent placement represents the fastest growing medical device implant. Complications of stent implantation include acute and subacute vessel closure, as well as late restenosis. Currently, antiplatelet agents are used for preventive therapy. Cilostazol is a vasodilating antiplatelet agent that reversibly inhibits platelet aggregation induced by many factors. In seven randomized trials comparing cilostazol with either aspirin or ticlopidine, cilostazol was found to be superior to aspirin and equivalent to ticlopidine in decreasing both cardiac events and rates of restenosis. In addition, cilostazol was found to be well tolerated, with no reports of adverse hematologic events. Although further comparative trials are required, cilostazol appears to be a safe and effective alternative to clopidogrel and glycoprotein IIb/IIIa receptor antagonists following intracoronary stent implantation.

Platelet glycoprotein IIb/IIIa—receptor inhibitors in patients with acute coronary syndromes or undergoing percutaneous coronary interventions: a review

Background: Over 12.2 million Americans are affected by acute coronary syndromes (ACS) resulting from arterial thrombosis after atherosclerotic plaque rupture. The mechanism of thrombosis is based on the platelet activation pathway, facilitated by expression of the platelet glycoprotein (GP) IIb/IIIa receptors. The platelet GP IIb/IIIa—receptor inhibitors represent a new class of drugs, of which abciximab, eptifibatide, and tirofiban have been approved for use in the medical management of ACS and as adjunctive therapy in percutaneous coronary interventions (PCIs). Objective: This article reviews the results of published multicenter, randomized, placebo-controlled, double-blind trials of the efficacy and safety of platelet GP IIb/IIIa—receptor inhibitors in patients with coronary artery disease. Methods: To identify articles for this review, a search of MEDLINE ® for the years 1994 through 2000 was conducted using the key words myocardial ischemia, unstable angina, angioplasty, stent, abciximab, eptifibatide, tirofiban, lamifiban, and platelet aggregation inhibitors. Relevant review articles were consulted as well as reports of clinical studies. Conclusions: Three GP IIb/IIIa—receptor inhibitors—abciximab, eptifibatide, and tirofiban—are approved by the US Food and Drug Administration as adjunctive therapy in patients undergoing PCI. Eptifibatide and tirofiban are also indicated for the medical management of patients with unstable angina and non—ST-segment—elevation myocardial infarction. The use of GP IIb/IIIa—receptor inhibitors as a component of management with fibrinolytic agents is under investigation. Studies comparing the efficacy of tirofiban and abciximab in patients undergoing planned PCI with intracoronary stent placement are in progress. Until data are available from long-term trials and head-to-head comparisons of these agents, it is not possible to generalize about their overall or comparative efficacy.

Actual outpatient PTCA: Results of the OUTCLAS pilot study

This study tested the safety and feasibility of coronary angioplasty on an outpatient basis. The purpose of this approach includes cost-effectiveness and patient comfort. Included were 159 patients treated with balloon angioplasty or intracoronary stent placement, all performed via the radial artery with 6 French guiding catheters. Patients were selected for same-day discharge based on the absence of any adverse predictor for subacute occlusion or unfavorable clinical outcome during the first 24 hr after successful PTCA. One hundred and six (66%) patients were discharged 4-6 hr after PTCA. Stents were used in 40% of patients. There were no cardiac or vascular complications. We conclude that outpatient PTCA, performed via the radial artery, is both safe and feasible in a large part of a routine PTCA population.

Platelet and leukocyte deactivation after intracoronary stent placement in patients receiving combined antiplatelet therapy.

Activated platelets and leukocytes have been demonstrated to play a role in the development of stent thrombosis, and coronary angioplasty has been shown to result in activation of platelets, leukocytes, and endothelial cells. We aimed to evaluate the effects of intracoronary stent placement and aspirin plus ticlopidine treatment on platelets, leukocytes, and endothelial cells via observing the serial changes in the circulating soluble forms of adhesion molecules in 54 patients with coronary artery disease, who had elective coronary angioplasty and stent implantation for a single lesion of the left anterior descending artery. After stent placement, intravenous heparin infusion was administered only for 24 hours, and aspirin plus ticlopidine treatment was applied for 1 month. Venous blood samples were drawn before stent placement, and repeated 24 and 48 hours after the procedure. Patients were excluded if they had had recent cardiovascular events or any illness that might influence platelet, leukocyte, and endothelial cell function. The plasma level of sL-selectin was significantly decreased 48 hours after coronary stenting (636+/-110 ng/mL vs 567+/-93 ng/mL; P = 0.001, respectively). Likewise, the plasma level of sP-selectin was also decreased significantly 48 hours after the procedure (260+/-61 ng/mL vs 233+/-83 ng/mL, P = 0.01). The sE-selectin level was found to be significantly increased 24 hours (31+/-9 ng/mL vs 39+/-12 ng/mL, P = 0.0001) and 48hours(31+/-9 ng/mL vs 42+/-15 ng/mL, P = 0.001) after coronary stenting. The results of our study suggest that significant platelet and leukocyte deactivation take place in patients treated with combined antiplatelet therapy after stenting; endothelial cell activation also occurs during this treatment.

Does the timing of myocardial perfusion imaging after intracoronary stent placement impact on the detection of restenosis? Indu G. Poornima, David O. Hodge, Todd D. Miller, Raymond J. Gibbons, Timothy F. Christian. Mayo Clinic, Rochester, MN

Does the timing of myocardial perfusion imaging after intracoronary stent placement impact on the detection of restenosis? Indu G. Poornima, David O. Hodge, Todd D. Miller, Raymond J. Gibbons, Timothy F. Christian. Mayo Clinic, Rochester, MN

Early and mid-term angiographic and clinical results after intracoronary duet stent placement.

The Duet stent (Guidant/Advanced Cardiovascular Systems) is a new stent with a corrugated ring design and very limited data on its short- and mid-term performance. Accordingly, in this study we sought to determine the early and mid-term clinical and angiographic outcomes in a moderate-sized series of 86 consecutive patients who underwent placement of 108 premounted Duet stents in 98 coronary lesions. Procedural success, accomplished in all patients, was accompanied by a significant reduction in lesion severity from 89% +/- 11% before to 5% +/- 3% diameter stenosis after the procedure (P = 0.0001) and a 0.9% incidence of subacute stent thrombosis. Angiographic restudy at 5.7 months in 89% of eligible patients revealed a binary in-stent restenosis rate of 26%. Coronary stenting with the new Duet stent confers a low risk of stent thrombosis and a favorable mid-term clinical and angiographic outcome despite the presence of a large proportion of patients at high risk of in-stent restenosis.

A multicentre study to evaluate the safety and tolerability of tirofiban in patients undergoing intracoronary stent placement

A multicentre study to evaluate the safety and tolerability of tirofiban in patients undergoing intracoronary stent placement

Antithrombotic Therapy during and after Intracoronary Stenting

Objective: To evaluate the impact on patient outcomes of antithrombotic therapy during and after intracoronary stenting. Data Sources: A MEDLINE search (1966-July 2000) for English-language clinical trials and review articles using the search terms stent and coronary with one or more of the following search terms: abciximab, tirofiban, orofiban, xemilofiban, eptifibatide, aspirin, heparin, enoxaparin, tinzaparin, dalteparin, hirudin, danaparoid, dipyridamole, cilostazol, dextran, warfarin, anticoagulant, ticlopidine, and Clopidogrel. References from these articles were reviewed for additional articles. Pharmaceutical companies were contacted to identify unpublished studies. A total of 177 sources were initially identified. Study Selection: Studies were selected through an unblinded individual review for prospective, randomized clinical trials evaluating patient outcomes related to antithrombotic therapy during or after intracoronary stent placement. Additional human and animal studies were included for background and introductory information. Data Extraction: Patient characteristics in each study were compared with those of the overall stent population. The primary end point measurements were defined. The completeness of follow-up and power analysis was assessed. Data Synthesis: Intracoronary stenting is now a common modality for maintaining patency of occluded arteries. Antithrombotic therapy during coronary artery stent placement is changing as knowledge about the pathophysiology of thrombus formation expands and new medications become available. Development of new stent placement techniques, new stent designs, and methods of restenosis irradiation or prevention have coincided with evolving antithrombotic regimens. Conclusions: The current antithrombotic regimen used in coronary artery stenting is complex, but has a lower incidence of hemorrhagic complications and thrombosis compared with previous anticoagulant regimens. Antithrombotic therapy may need to be tailored to individual patient contraindications.

Clopidogrel

Clopidogrel is an ADP receptor antagonist that is indicated for the reduction of atherosclerotic events including myocardial infarction, ischaemic stroke and vascular death in patients with atherosclerosis manifested by recent stroke, myocardial infarction or established peripheral vascular disease. In the 19 185 patients enrolled in the multicentre, randomised double-blind CAPRIE study, the annual risk of the combined end-point of ischaemic stroke, myocardial infarction and death from vascular disease (vascular death) was significantly lower during treatment with clopidogrel 75 mg/day than aspirin 325 mg/day [5.3 vs 5.8%/year, respectively; relative risk reduction (RRR) 8.7%, p = 0.043] after a mean follow-up of 1.9 years. Clopidogrel provided even greater reductions in the risk of recurrent ischaemic events than aspirin in patients with a history of coronary artery bypass surgery, diabetes mellitus and in those receiving concomitant lipid-lowering therapy. Moreover there was a significant reduction in the incidence of hospitalisation in patients treated with clopidogrel. In a patient population (Saskatchewan, Canada) with a greater risk of ischaemic events than the CAPRIE study population, the number of patients needed to be treated with clopidogrel to prevent 1 ischaemic event was estimated to be 70 (vs 200 in the CAPRIE study). In randomised trials and registry surveys, clopidogrel 75 mg/day plus aspirin had similar efficacy (as measured by adverse cardiac outcomes) to ticlopidine 250mg twice daily plus aspirin during the 30 days after placement of intracoronary stents. Tolerability of clopidogrel was significantly better than ticlopidine in the randomised, double-blind CLASSICS study. Among patients treated with clopidogrel or aspirin in the CAPRIE study, the overall gastrointestinal tolerability of clopidogrel was generally better than that of aspirin; the frequency of gastrointestinal haemorrhage was significantly lower among patients treated with clopidogrel than aspirin. Diarrhoea, rash and pruritus were significantly more common with clopidogrel than aspirin. Clopidogrel was significantly more effective than aspirin in the prevention of vascular events (ischaemic stroke, myocardial infarction or vascular death) [corrected] in patients with atherothrombotic disease manifested by recent myocardial infarction, recent ischaemic stroke or symptomatic peripheral arterial occlusive disease [corrected] in the CAPRIE study. The overall tolerability profile of the drug was similar to that of aspirin, although gastrointestinal haemorrhage occurred significantly less often in clopidogrel recipients. The drug is widely used in combination with aspirin for the prevention of atherothrombosis after placement of intravascular stents, and available data suggest that this combination is as effective as ticlopidine plus aspirin for this indication.

Synergy between intracoronary stenting and abciximab in improving angiographic and clinical outcomes of primary angioplasty in acute myocardial infarction

This study examined 650 consecutive patients who presented with an acute myocardial infarction and were treated with primary angioplasty within 12 hours of symptom onset between August 1995 and December 1998. Patients were placed into 4 treatment groups depending on the adjunctive therapy they received: group 1, percutaneous transluminal coronary angioplasty (PTCA) (“balloon PTCA alone”; n = 220); group 2, PTCA plus intracoronary stent placement (“stent”; n = 128); group 3, PTCA plus abciximab therapy (“abciximab”; n = 104); and group 4, PTCA plus intracoronary stent placement plus abciximab therapy (“stent/abciximab”; n = 198). The patients’ clinical characteristics, severity of disease, and total ischemia time on presentation were similar. At baseline, abciximab and stent/abciximab groups had a higher incidence of thrombus on coronary angiography. Postprocedural quantitative coronary analysis showed a significantly larger minimum luminal diameter in the stent and stent/abciximab groups than PTCA alone. Overall, stents were most efficacious in reducing target vessel revascularization rate, whereas abciximab was associated with a higher postprocedural Thrombolysis In Myocardial Infarction-3 trial flow and less “no reflow.” The best angiographic result was achieved in the stent/abciximab group. Similarly, the primary combined end point of death, myocardial infarction, and target vessel revascularization at 30 days was the lowest (6.1%) in the stent/abciximab group. The combination of abciximab and stenting in primary angioplasty for acute myocardial infarction is thus synergistic and is associated with improved angiographic and clinical results at 30-day follow-up.

Adjunctive intracoronary dipyridamole in the interventional treatment of small coronary arteries: A prospectively randomized trial

Background Patients undergoing intracoronary stent placement or balloon angioplasty for the treatment of small coronary arteries are at an increased risk of an adverse outcome from a higher incidence of abrupt closure and restenosis. Intracoronary thrombus formation plays a key role in the pathogenesis of abrupt vessel closure and of restenosis. Dipyridamole prevents platelet aggregation by a mechanism that differs from aspirin. The purpose of this study was to investigate the effect of intracoronary dipyridamole on acute complications and restenosis after percutaneous transluminal coronary angioplasty. Methods In a prospectively randomized study including 491 dilatations of coronary arteries with a diameter <2.75 mm, additional intracoronary application of dipyridamole was compared with conventional pretreatment consisting of heparin and aspirin. Study end points were defined as incidence of abrupt vessel closure, myocardial infarction, angiographic restenosis, and target vessel revascularization rate. Results Intracoronary dipyridamole was associated with a significant reduction of abrupt vessel closure (2.8% vs 8.6%; P =.005) and a nonsignificant reduction of myocardial infarction (1.6% vs 4.5%; P =.07) after percutaneous transluminal coronary angioplasty. Net gain 6 months after angioplasty was significantly higher in the dipyridamole group (0.60 ± 0.35 mm vs 0.42 ± 0.34 mm; P <.001). However, dipyridamole failed to reduce the incidence of angiographic restenosis (41.6% vs 49.1%; P =.11) and target vessel revascularization rate (20.6% vs 269%; P =.12). Conclusions Intracoronary dipyridamole reduces the incidence of adverse cardiovascular events in the first 48 hours after balloon angioplasty of small coronary arteries. Reduction of restenosis rates failed to reach statistical significance. However, a significant increase in net gain was observed. Thus intracoronary application of dipyridamole should be considered in the treatment of small coronary arteries when intracoronary stenting is not appropriate. (Am Heart J 2000;139:1039-45.)

Acute myocardial infarction--a late complication of intracoronary stent placement.

Myocardial infarction (MI) as the first indication of postangioplasty restenosis is extremely rare, and it has been speculated that the fibroproliferative restenotic lesion is less likely to undergo plaque rupture than the lipid-laden native atherosclerotic lesion. The present study was designed to examine whether intracoronary stent implantation affects this course. In all, 994 consecutive patients who underwent angioplasty and intracoronary stent implantation in our hospital were reviewed retrospectively for the occurrence of MI. Eight patients (0.8%), all male and hypertensive, aged 33-83 years, presented with an MI due to stent occlusion more than 30 days following stenting (range: 35-398 days). In two patients, MI occurred 3 and 5 h, respectively, following completion of a maximal high-level exercise test that was negative for ischemia. Angiography revealed complete occlusion or significant stenosis of the stent in all eight patients, with an obvious intimal dissection in either edge of the stent in six patients. Except for gender and hypertension, no correlation was found with other risk factors, vessel involved, initial angiographic results, or with stent design, diameter, or length. Myocardial infarction as a late complication of successful stent implantation occurred in 0.8% of our patients. This is only the lower bound of the estimated frequency for such an event. We hypothesize that the transition point between the relatively fixed stent and the normal artery is exposed to high deformation stress which makes it vulnerable to rupture and dissection. Strenuous exercise and hypertension may increase the deformation stress and the risk of intimal rupture.

Placement of Intracoronary Stents Mounted on "Over the Wire" Balloon Catheters Without Using Long Guidewires

The aim of this study is to investigate the feasibility, effectiveness, and safety of placement of intracoronary stents mounted on “over the wire” balloon catheters without using long guidewires. Fifteen consecutive patients underwent GR II stent placement. Over the wire balloon catheters and short guidewires were used. The new method was successful in 14 of 15 cases. No complications were observed. This novel technique using a short (instead of long) guidewire to place intracoronary stents mounted on over the wire balloon catheters was successful, and more convenient. (J Interven Cardiol 2000; 13:27–30)

Clinical outcome after multivessel coronary stent implantation

Background Percutaneous transluminal coronary angioplasty (PTCA) has been shown to be an effective therapy for multivessel coronary artery disease, although more frequent acute complications and an increased need to repeat revascularization than with single-vessel PTCA continue to be limitations. Intracoronary stent placement has been shown to reduce the rate of acute complications and the need for subsequent revascularization. We sought to evaluate the outcome among patients undergoing successful multivessel coronary intervention with stents. Methods The participants were 175 patients without coronary artery bypass grafts who underwent multivessel coronary revascularization in which stent placement was attempted in all treated segments from January 1992 through March 1998 at our institution. Clinical and angiographic characteristics and outcomes were analyzed. Results Stent placement was attempted for 428 coronary lesions. The angiographic success rate was 100%. Modified American College of Cardiology–American Heart Association type B2 and C lesions accounted for 74.5% of the lesions. Three patients (1.7%) died in the hospital. No patient had Q-wave myocardial infarction or needed coronary artery bypass grafting. Procedural success was achieved for 172 patients (98.3%). The Kaplan-Meier probability of freedom from death or myocardial infarction at 12 months was 96.6%, of any revascularization was 81.7%, and of death, myocardial infarction, and any revascularization combined was 79.8%. The use of long-acting nitrates at 12 months was reduced (34.3% versus 19.1%, P = .01). Conclusions Multivessel coronary stent placement is associated with an excellent procedural success rate despite a high rate of adverse lesion characteristics and a high event-free survival rate during the follow-up period. The likelihood that revascularization will not have to be repeated during the first follow-up year is significantly better than that for historic controls of multivessel PTCA. (Am Heart J 1999;138:1105-10.)

Indications for intracoronary stent placement: the european view. Working Group on Coronary Circulation of the European Society of Cardiology.

In Europe, no written official guidelines on indications for coronary stent placement are available. We therefore assessed the opinions of European interventional cardiologists on these indications. In April 1997, a questionnaire was sent to the members of the Working Group on Coronary Circulation of the European Society of Cardiology with interventional cardiology as the main activity. A total of 165 questionnaires were returned and analysed. For the treatment of acute or threatened vessel closure during PTCA, the threshold for stenting is set at the level of a type C dissection by 42% of the cardiologists, while 22% stent any form of dissection and 13% require an impaired TIMI flow. A suboptimal PTCA result necessitating stenting is defined as a residual stenosis of >50% by 35% or of 30 >30% by 55% of the respondents. When considering primary prevention of restenosis, only 2% unconditionally stent focal, new-onset lesions in native coronary arteries, 44% refrain from stenting in a case of a stent-like PTCA result (</=30% residual stenosis) and 73% think that stent types other than the Palmaz-Schatz may be implanted for this indication. Restenotic lesions are unconditionally stented by 30% of the interventionists while 64% reserve this option only for suboptimal PTCA results. Amongst the other indications, stenting is considered to be the treatment of choice as follows: chronic total occlusion, 85%; saphenous vein graft lesions, 59%; aorto-coronary ostial lesions, 64%; and primary intervention for myocardial infarction: 59%. European interventional cardiologists have integrated current literature on stenting into their daily practice. The most cited indications (threatened vessel closure and suboptimal PTCA results) are not supported by randomized trials. The variations in the conclusions from randomized trials may be explained by the general expectation that stenting will improve PTCA results.

Coronary artery stent placement in patients with variant angina refractory to medical treatment

We performed a prospective study to establish the efficacy of coronary stent placement in a highly selected group of patients with focal coronary artery spasm in whom anginal attacks could not be prevented by full medical therapy. The results of this study indicate that intracoronary stent placement may represent an alternative and feasible treatment for patients with vasospastic angina refractory to aggressive medical therapy.

Intracoronary stent placement proximal to a myocardial bridge: immediate and long-term results.

The intracoronary stent placement in a lesion proximal to a myocardial bridge is of special importance and is considered to be a challenge for the interventional cardiologist. In this study 4 cases of stent implantation proximal to a coronary bridged segment are described. In all cases complications were observed after the procedure. The patients remained free of symptoms and the exercise TI201 test was negative for ischemia 8.5+/-2.6 months later. Although there is skepticism because of the abnormal coronary flow pattern, the endothelial dysfunction and the subsequent thrombogenicity, the stent placement proximal to a myocardial bridge was safe and with favorable long term results in all 4 cases. However, further studies in large populations are necessary.

Angiographic restenosis rate in patients with chronic total occlusions and subtotal stenoses after initially successful intracoronary stent placement

The 5-month angiographic in-stent restenosis rate did not differ between patients with chronic total occlusions (n = 43) and subtotal stenoses (n = 43) equally matched for diabetes status, exact stent design, final expanded stent diameter, stent length, and residual percent diameter stenosis after stent placement; it was 32.5% and 27.9% for those with chronic total occlusions and subtotal stenoses, respectively (p = 0.638). Furthermore, the stent occlusion rate (4.6% vs 6.9%, respectively) was low in both patient groups.