Percutaneous coronary interventions in Europe: prevalence, numerical estimates, and projections based on data up to 2004

AIMS: A registry mandated by the European Society of Cardiology collects data on trends in interventional cardiology within Europe. Special interest focuses on relative increases and ratios in new techniques and their distributions across Europe. We report the data through 2004 and give an overview of the development of coronary interventions since the first data collection in 1992. METHODS AND RESULTS: Questionnaires were distributed yearly to delegates of all national societies of cardiology represented in the European Society of Cardiology. The goal was to collect the case numbers of all local institutions and operators. The overall numbers of coronary angiographies increased from 1992 to 2004 from 684 000 to 2 238 000 (from 1250 to 3930 per million inhabitants). The respective numbers for percutaneous coronary interventions (PCIs) and coronary stenting procedures increased from 184 000 to 885 000 (from 335 to 1550) and from 3000 to 770 000 (from 5 to 1350), respectively. Germany was the most active country with 712 000 angiographies (8600), 249 000 angioplasties (3000), and 200 000 stenting procedures (2400) in 2004. The indication has shifted towards acute coronary syndromes, as demonstrated by rising rates of interventions for acute myocardial infarction over the last decade. The procedures are more readily performed and perceived safer, as shown by increasing rate of "ad hoc" PCIs and decreasing need for emergency coronary artery bypass grafting (CABG). In 2004, the use of drug-eluting stents continued to rise. However, an enormous variability is reported with the highest rate in Switzerland (70%). If the rate of progression remains constant until 2010 the projected number of coronary angiographies will be over three million, and the number of PCIs about 1.5 million with a stenting rate of almost 100%. CONCLUSION: Interventional cardiology in Europe is ever expanding. New coronary revascularization procedures, alternative or complementary to balloon angioplasty, have come and gone. Only stenting has stood the test of time and matured to the default technique. Facilitated access to PCI, more complete and earlier detection of coronary artery disease promise continued growth of the procedure despite the uncontested success of prevention.

Effects of percutaneous coronary interventions in silent ischemia after myocardial infarction: the SWISSI II randomized controlled trial

CONTEXT: The effect of a percutaneous coronary intervention (PCI) on the long-term prognosis of patients with silent ischemia after a myocardial infarction (MI) is not known. OBJECTIVE: To determine whether PCI compared with drug therapy improves long-term outcome of asymptomatic patients with silent ischemia after an MI. DESIGN, SETTING, AND PARTICIPANTS: Randomized, unblinded, controlled trial (Swiss Interventional Study on Silent Ischemia Type II [SWISSI II]) conducted from May 2, 1991, to February 25, 1997, at 3 public hospitals in Switzerland of 201 patients with a recent MI, silent myocardial ischemia verified by stress imaging, and 1- or 2-vessel coronary artery disease. Follow-up ended on May 23, 2006. INTERVENTIONS: Percutaneous coronary intervention aimed at full revascularization (n = 96) or intensive anti-ischemic drug therapy (n = 105). All patients received 100 mg/d of aspirin and a statin. MAIN OUTCOME MEASURES: Survival free of major adverse cardiac events defined as cardiac death, nonfatal MI, and/or symptom-driven revascularization. Secondary measures included exercise-induced ischemia and resting left ventricular ejection fraction during follow-up. RESULTS: During a mean (SD) follow-up of 10.2 (2.6) years, 27 major adverse cardiac events occurred in the PCI group and 67 events occurred in the anti-ischemic drug therapy group (adjusted hazard ratio, 0.33; 95% confidence interval, 0.20-0.55; P<.001), which corresponds to an absolute event reduction of 6.3% per year (95% confidence interval, 3.7%-8.9%; P<.001). Patients in the PCI group had lower rates of ischemia (11.6% vs 28.9% in patients in the drug therapy group at final follow-up; P = .03) despite fewer drugs. Left ventricular ejection fraction remained preserved in PCI patients (mean [SD] of 53.9% [9.9%] at baseline to 55.6% [8.1%] at final follow-up) and decreased significantly (P<.001) in drug therapy patients (mean [SD] of 59.7% [11.8%] at baseline to 48.8% [7.9%] at final follow-up). CONCLUSION: Among patients with recent MI, silent myocardial ischemia verified by stress imaging, and 1- or 2-vessel coronary artery disease, PCI compared with anti-ischemic drug therapy reduced the long-term risk of major cardiac events. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00387231.

Coronary collateral flow in response to endurance exercise training

BACKGROUND: In humans, it is not known whether physical endurance exercise training promotes coronary collateral growth. The following hypotheses were tested: the expected collateral flow reduction after percutaneous coronary intervention of a stenotic lesion is prevented by endurance exercise training; collateral flow supplied to an angiographically normal coronary artery improves in response to exercise training; there is a direct relationship between the change of fitness after training and the coronary collateral flow change. METHODS AND RESULTS: Forty patients (age 61+/-8 years) underwent a 3-month endurance exercise training program with baseline and follow-up assessments of coronary collateral flow. Patients were divided into an exercise training group (n=24) and a sedentary group (n=16) according to the fact whether they adhered or not to the prescribed exercise program, and whether or not they showed increased endurance (VO2max in ml/min per kg) and performance (W/kg) during follow-up versus baseline bicycle spiroergometry. Collateral flow index (no unit) was obtained using pressure sensor guidewires positioned in the coronary artery undergoing percutaneous coronary intervention and in a normal vessel. In the vessel initially undergoing percutaneous coronary intervention, there was an increase in collateral flow index among exercising but not sedentary patients from 0.155+/-0.081 to 0.204+/-0.056 (P=0.03) and from 0.189+/-0.084 to 0.212+/-0.077 (NS), respectively. In the normal vessel, collateral flow index changes were from 0.176+/-0.075 to 0.227+/-0.070 in the exercise group (P=0.0002), and from 0.219+/-0.103 to 0.238+/-0.086 in the sedentary group (NS). A direct correlation existed between the change in collateral flow index from baseline to follow-up and the respective alteration of VO2max (P=0.007) and Watt (P=0.03). CONCLUSION: A 3-month endurance exercise training program augments coronary collateral supply to normal vessels, and even to previously stenotic arteries having undergone percutaneous coronary intervention before initiating the program. There appears to be a dose-response relation between coronary collateral flow augmentation and exercise capacity gained.

Does the beta-blocker nebivolol increase coronary flow reserve?

INTRODUCTION: Nebivolol, a highly selective beta1-adrenergic receptor-blocker, increases basal and stimulated endothelial nitric oxide (NO)-release. It is unknown, whether coronary perfusion is improved by the increase in NO availability. Therefore, we sought to evaluate the effect of nebivolol on coronary flow reserve (CFR) and collateral flow. METHODS: Doppler-flow wire derived coronary flow velocity measurements were obtained in ten controls and eight patients with coronary artery disease (CAD) at rest and after intracoronary nebivolol. CFR was defined as maximal flow during adenosine-induced hyperemia divided by resting flow. In the CAD group, collateral flow was determined after dilatation of a flow-limiting coronary stenosis. Collateral flow index (CFI) was defined as the ratio of flow velocity during balloon inflation divided by resting flow. RESULTS: CFR at rest was 3.0+/-0.6 in controls and 2.1+/-0.4 in CAD patients. After intracoronary doses of 0.1, 0.25, and 0.5 mg nebivolol, CFR increased to 3.4+/-0.7, 3.9+/-0.9, and 4.0+/-0.1 (p<0.01) in controls, and to 2.3+/-0.7, 2.6+/-0.9, and 2.6+/-0.5 (p<0.05) in CAD patients. CFI decreased significantly with intracoronary nebivolol and correlated to changes in heart rate (r=0.75, p<0.001) and rate-pressure product (r=0.59, p=0.001). DISCUSSION: Intracoronary nebivolol is associated with a significant increase in CFR due to reduction in resting flow (controls), or due to an increase in maximal coronary flow (CAD patients). CFI decreased with nebivolol parallel to the reduction in myocardial oxygen consumption.

Local vascular dysfunction after coronary paclitaxel-eluting stent implantation

BACKGROUND: Paclitaxel-eluting stents (PES) have been shown to reduce the rate of restenosis and the need for repeated revascularization procedures compared with bare metal stents. However, long-term effects of paclitaxel on vascular function are unknown. The purpose of the present study was to assess coronary vasomotor response to exercise after paclitaxel-eluting stent implantation. METHODS: Coronary vasomotion was evaluated by biplane quantitative coronary angiography at rest and during supine bicycle exercise in 27 patients with coronary artery disease. Twelve patients were treated with a bare metal stent (controls), and fifteen patients with a paclitaxel-eluting stent. All patients were restudied 6+/-2 (range 2-12) months after stent implantation. Minimal luminal diameter, stent diameter, proximal, distal and a reference vessel diameter were determined. RESULTS: Reference vessels showed exercise-induced vasodilation in both groups (+20+/-5% controls; +26+/-3% PES group). Vasomotion within the stented vessel segments was abolished. In the controls, the adjacent segments proximal and distal to the stent showed exercise-induced vasodilation (+17+/-3% and +24+/-4%). In contrast, there was exercise-induced vasoconstriction of the proximal and distal vessel segments adjacent to the paclitaxel-eluting stent (-13+/-6% and -18+/-4%; p<0.005). After sublingual nitroglycerin, the proximal and distal vessel segments dilated in both groups. Exercise-induced vasoconstriction adjacent to paclitaxel-eluting stent correlated inversely with the time interval after stent implantation. CONCLUSIONS: Paclitaxel-eluting stent implantation is associated with exercise-induced vasoconstriction in the persistent region suggesting endothelial dysfunction as the underlying mechanism. Improvement of vascular function occurs over time, indicating delayed vascular healing.

Myeloid-related protein 8/14 complex is released by monocytes and granulocytes at the site of coronary occlusion: a novel, early, and sensitive marker of acute coronary syndromes

AIMS: We investigated whether myeloid-related protein 8/14 complex (MRP8/14) expressed by infiltrating monocytes and granulocytes may represent a mediator and early biomarker of acute coronary syndromes (ACS). METHODS AND RESULTS: Immunohistochemistry of coronary thrombi was done in 41 ACS patients. Subsequently, levels of MRP8/14 were assessed systemically in 75 patients with ACS and culprit lesions, with stable coronary artery disease (CAD), or with normal coronary arteries. In a subset of patients, MRP8/14 was measured systemically and at the site of coronary occlusion. Macrophages and granulocytes, but not platelets stained positive for MRP8/14 in 76% of 41 thrombi patients. In ACS, local MRP8/14 levels [22.0 (16.2-41.5) mg/L] were increased when compared with systemic levels [13.4 (8.1-14.7) mg/L, P = 0.03]. Systemic levels of MRP8/14 were markedly elevated [15.1 (12.1-21.8) mg/L, P = 0.001] in ACS when compared with stable CAD [4.6 (3.5-7.1) mg/L] or normals [4.8 (4.0-6.3) mg/L]. Using a cut-off level of 8 mg/L, MRP8/14 but not myoglobin or troponin, identified ACS presenting within 3 h from symptom onset. CONCLUSION: In ACS, MRP8/14 is markedly expressed at the site of coronary occlusion by invading phagocytes. The occurrence of elevated MRP8/14 in the systemic circulation prior to markers of myocardial necrosis makes it a prime candidate for the detection of unstable plaques and management of ACS.

Drug-eluting stent and coronary thrombosis: biological mechanisms and clinical implications

Although rare, stent thrombosis remains a severe complication after stent implantation owing to its high morbidity and mortality. Since the introduction of drug-eluting stents (DES), most interventional centers have noted stent thrombosis up to 3 years after implantation, a complication rarely seen with bare-metal stents. Some data from large registries and meta-analyses of randomized trials indicate a higher risk for DES thrombosis, whereas others suggest an absence of such a risk. Several factors are associated with an increased risk of stent thrombosis, including the procedure itself (stent malapposition and/or underexpansion, number of implanted stents, stent length, persistent slow coronary blood flow, and dissections), patient and lesion characteristics, stent design, and premature cessation of antiplatelet drugs. Drugs released from DES exert distinct biological effects, such as activation of signal transduction pathways and inhibition of cell proliferation. As a result, although primarily aimed at preventing vascular smooth muscle cell proliferation and migration (ie, key factors in the development of restenosis), they also impair reendothelialization, which leads to delayed arterial healing, and induce tissue factor expression, which results in a prothrombogenic environment. In the same way, polymers used to load these drugs have been associated with DES thrombosis. Finally, DES impair endothelial function of the coronary artery distal to the stent, which potentially promotes the risk of ischemia and coronary occlusion. Although several reports raise the possibility of a substantially higher risk of stent thrombosis in DES, evidence remains inconclusive; as a consequence, both large-scale and long-term clinical trials, as well as further mechanistic studies, are needed. The present review focuses on the pathophysiological mechanisms and pathological findings of stent thrombosis in DES.

Temporary scaffolding of coronary arteries with bioabsorbable magnesium stents: a prospective, non-randomised multicentre trial

BACKGROUND: Coronary stents improve immediate and late results of balloon angioplasty by tacking up dissections and preventing wall recoil. These goals are achieved within weeks after angioplasty, but with current technology stents permanently remain in the artery, with many limitations including the need for long-term antiplatelet treatment to avoid thrombosis. We report a prospective multicentre clinical trial of coronary implantations of absorbable magnesium stents. METHODS: We enrolled 63 patients (44 men; mean age 61.3 [SD 9.5 years]) in eight centres with single de novo lesions in a native coronary artery in a multicentre, non-randomised prospective study. Follow-up included coronary angiography and intravascular ultrasound at 4 months and clinical assessment at 6 months and 12 months. The primary endpoint was cardiac death, non-fatal myocardial infarction, or clinically driven target lesion revascularisation at 4 months FINDINGS: 71 stents, 10-15 mm in length and 3.0-3.5 mm in diameter, were successfully implanted after pre-dilatation in 63 patients. Diameter stenosis was reduced from 61.5 (SD 13.1%) to 12.6 (5.6%) with an acute gain of 1.41 mm (0.46 mm) and in-stent late loss of 1.08 mm (0.49 mm). The ischaemia-driven target lesion revascularisation rate was 23.8% after 4 months, and the overall target lesion revascularisation rate was 45% after 1 year. No myocardial infarction, subacute or late thrombosis, or death occurred. Angiography at 4 months showed an increased diameter stenosis of 48.4 (17.0%). After serial intravascular ultrasound examinations, only small remnants of the original struts were visible, well embedded into the intima. Neointimal growth and negative remodelling were the main operating mechanisms of restenosis. INTERPRETATION: This study shows that biodegradable magnesium stents can achieve an immediate angiographic result similar to the result of other metal stents and can be safely degraded after 4 months. Modifications of stent characteristics with prolonged degradation and drug elution are currently in development.

Clinical relevance of coronary angiography at the time of percutaneous closure of a patent foramen ovale

BACKGROUND: The value of incidental coronary angiography during percutaneous shunt closure to screen for asymptomatic coronary artery disease (CAD) is unknown. METHODS: On the occasion of percutaneous closure of patent foramen ovale (PFO), incidental coronary angiography routinely offered to men >40 and women >50 years, or younger patients with particular risk patterns, was performed in 575 patients (64% men, mean age 55 +/- 10 years, mean 1.5 +/- 1.1 cardiovascular risk factors) without overt history, signs, or symptoms of CAD. RESULTS: CAD was found in 164 patients (29%); 53 (9%) had >or=50% diameter stenoses. Thirty patients (5%) had one-vessel, 13 (2%) two-vessel, and 10 (2%) three-vessel disease. Patients with CAD (n = 164) were older (60 +/- 9 vs. 53 +/- 10 years; P < 0.0001), more frequently male (76% vs. 59%; P = 0.0002), and had a higher body mass index (26.5 +/- 4.0 vs. 25.4 +/- 4.6; P = 0.006) and more cardiovascular risk factors (2.0 +/- 1.1 vs. 1.2 +/- 1.0; P < 0.0001). There were six procedural complications (1%). Two were unequivocally related to coronary angiography: one minor stroke (diplopia), and one iatrogenic dissection of the right coronary ostium requiring stenting. Furthermore, four arteriovenous fistulae at the puncture site requiring elective surgical closure were possibly related to coronary angiography. Forty-five patients (8% of total) underwent percutaneous (n = 43) or surgical (n = 2) revascularization. CONCLUSIONS: In selected asymptomatic patients referred for percutaneous PFO closure, incidental coronary angiography discloses a rather high prevalence of clinically unsuspected CAD. These findings are relevant not only for timely revascularization but also for maintenance of long-term antiplatelet therapy beyond the few months recommended after PFO closure.

[Manifestation and course of coronary heart disease in men and women--consequences for diagnosis and treatment]

Gender related issues in manifestation, diagnosis and treatment of coronary artery disease are important but still not well recognized. Women are more likely to present late after first symptoms of myocardial infarction. Myocardial infarction is more often unrecognized. In regard to complications after myocardial infarctions ventricular tachycardia and cardiac arrest are more frequent and women are also more likely to develop heart failure or cardiogenic shock. The reason for this is most probably the fact that women presenting with myocardial infarction are of older age and have a higher incidence of co-morbidities. Thrombolysis and coronary angioplasty are less often performed in women in the setting of myocardial infarction. However there is a clear trend toward improvement of this situation during the last years. The reopening rate of occluded coronary arteries with thrombolysis and with coronary angioplasty is similar in women compared to men. Perioperative risk with aorto-coronary bypass surgery is higher in women, which can not be fully explained by higher age and co-morbidities. However 10 years survival rate after aorto-coronary bypass-surgery is similar for men and women, although occlusion of venous grafts is seen more often in women. The benefit of structured cardiac rehabilitation after an acute event is similar for younger and older women and as good as in men. Positive effects of cardiac rehabilitation include increased physical performance, reduction of body fat, improvement of lipid-profiles and an improvement of the psychosocial situation and quality of life.

Biolimus-eluting stent with biodegradable polymer versus sirolimus-eluting stent with durable polymer for coronary revascularisation (LEADERS): a randomised non-inferiority trial

BACKGROUND: A novel stent platform eluting biolimus, a sirolimus analogue, from a biodegradable polymer showed promising results in preliminary studies. We compared the safety and efficacy of a biolimus-eluting stent (with biodegradable polymer) with a sirolimus-eluting stent (with durable polymer). METHODS: We undertook a multicentre, assessor-blind, non-inferiority study in ten European centres. 1707 patients aged 18 years or older with chronic stable coronary artery disease or acute coronary syndromes were centrally randomised by a computer-generated allocation sequence to treatment with either biolimus-eluting (n=857) or sirolimus-eluting (n=850) stents. The primary endpoint was a composite of cardiac death, myocardial infarction, or clinically-indicated target vessel revascularisation within 9 months. Analysis was by intention to treat. 427 patients were randomly allocated to angiographic follow-up, with in-stent percentage diameter stenosis as principal outcome measure at 9 months. The trial is registered with ClinicalTrials.gov, number NCT00389220. FINDINGS: We analysed all randomised patients. Biolimus-eluting stents were non-inferior to sirolimus-eluting stents for the primary endpoint at 9 months (79 [9%] patients vs 89 [11%], rate ratio 0.88 [95% CI 0.64-1.19], p for non-inferiority=0.003, p for superiority=0.39). Frequency of cardiac death (14 [1.6%] vs 21 [2.5%], p for superiority=0.22), myocardial infarction (49 [5.7%] vs 39 [4.6%], p=0.30), and clinically-indicated target vessel revascularisation (38 [4.4%] vs 47 [5.5%], p=0.29) were similar for both stent types. 168 (79%) patients in the biolimus-eluting group and 167 (78%) in the sirolimus-eluting group had data for angiographic follow-up available. Biolimus-eluting stents were non-inferior to sirolimus-eluting stents in in-stent percentage diameter stenosis (20.9%vs 23.3%, difference -2.2% [95% CI -6.0 to 1.6], p for non-inferiority=0.001, p for superiority=0.26). INTERPRETATION: Our results suggest that a stent eluting biolimus from a biodegradable polymer represents a safe and effective alternative to a stent eluting sirolimus from a durable polymer in patients with chronic stable coronary artery disease or acute coronary syndromes. FUNDING: Biosensors Europe SA, Switzerland.

Simultaneous subacute coronary drug-eluting stent thrombosis in two different vessels of a patient with factor V Leiden mutation

We review the case of a 46-year-old man who underwent elective percutaneous coronary intervention and stenting of the left anterior descending artery and right coronary artery with two sirolimus- and paclitaxel-eluting stents. Four days after angioplasty, he was readmitted with cardiogenic shock due to acute anterior and inferior myocardial infarction. Coronary angiography revealed subacute thrombosis of both stents, and balloon dilation was performed successfully thereafter. The follow-up investigations revealed that the patient was a carrier of factor V Leiden. We hereby discuss the importance of factor V Leiden as the most common cause of hypercoagulable state and its probable role in acute and subacute coronary stent thrombosis in drug-eluting stents.

Vascular adaptation of the internal thoracic artery graft early and late after bypass surgery

OBJECTIVE: Flow mismatch between the supplying artery and the myocardial perfusion region has been observed in patients with internal thoracic artery grafts. Thus coronary flow changes of arterial (internal thoracic artery grafts) and saphenous (saphenous vein grafts) bypass grafts were studied early and late after coronary artery bypass grafting. METHODS: Thirty patients undergoing elective bypass surgery (internal thoracic artery and saphenous vein grafts) were studied intraoperatively and (17 patients) 3 to 10 months postoperatively. Coronary flow was measured intraoperatively with the transit-time Doppler scanning technique. Postoperatively, flow velocity and coronary flow reserve were determined with the Doppler flow wire technique. Quantitative angiographic analysis was used to determine vessel size for calculation of absolute flow. RESULTS: Intraoperatively, internal thoracic artery graft flow was significantly lower than saphenous vein graft flow (31 +/- 8 vs 58 +/- 29 mL/min, P < .01). Postoperatively, internal thoracic artery graft flow increased significantly to 42 +/- 24 mL/min at 3 months and to 56 +/- 30 mL/min (P < .02 vs intraoperative value) at 10 months, respectively. However, saphenous vein graft flow remained unchanged over time (58 +/- 29 to 50 +/- 27 mL/min at 3 months and 46 +/- 27 mL/min at 10 months). Coronary flow reserve was abnormally low intraoperatively in the internal thoracic artery (1.3 +/- 0.3) and saphenous vein (1.6 +/- 0.5) grafts but increased significantly to normal values in both types of graft at follow-up. CONCLUSIONS: Bypass flow of the internal thoracic artery graft is significantly reduced intraoperatively when compared with that of the saphenous vein graft. However, 3 and 10 months after the operation, flow of the internal thoracic artery graft increases significantly and is similar to saphenous vein graft flow. This finding can be explained by an early flow mismatch of the native internal thoracic artery in the presence of a large perfusion territory. During follow-up, there is vascular remodeling of the internal thoracic artery, probably because of endothelium-mediated mechanisms.

Automated, compliant, high-flow common carotid to middle cerebral artery bypass

The authors describe the use of the Cardica C-Port xA Distal Anastomosis System to perform an automated, high-flow extracranial-intracranial bypass. The C-Port system has been developed and tested in coronary artery bypass surgery for rapid distal coronary artery anastomoses. Air-powered, it performs an automated end-to-side anastomosis within seconds by nearly simultaneously making an arteriotomy and inserting 13 microclips into the graft and recipient vessel. Intracranial use of the device was first simulated in a cadaver prepared for microsurgical anatomical dissection. The authors used this system in a 43-year-old man who sustained a subarachnoid hemorrhage after being assaulted and was found to have a traumatic pseudoaneurysm of the proximal intracranial internal carotid artery. The aneurysm appeared to be enlarging on serial imaging studies and it was anticipated that a bypass would probably be needed to treat the lesion. An end-to-side bypass was performed with the C-Port system using a saphenous vein conduit extending from the common carotid artery to the middle cerebral artery. The bypass was demonstrated to be patent on intraoperative and postoperative arteriography. The patient had a temporary hyperperfusion syndrome and subsequently made a good neurological recovery. The C-Port system facilitates the performance of a high-flow extracranial-intracranial bypass with short periods of temporary arterial occlusion. Because of the size and configuration of the device, its use is not feasible in all anatomical situations that require a high-flow bypass; however it is a useful addition to the armamentarium of the neurovascular surgeon.

Early- and long-term intravascular ultrasound and angiographic findings after bioabsorbable magnesium stent implantation in human coronary arteries

OBJECTIVES: This study aimed to evaluate the degradation rate and long-term vascular responses to the absorbable metal stent (AMS). BACKGROUND: The AMS demonstrated feasibility and safety at 4 months in human coronary arteries. METHODS: The PROGRESS-AMS (Clinical Performance and Angiographic Results of Coronary Stenting) was a prospective, multicenter clinical trial of 63 patients with coronary artery disease who underwent AMS implantation. Angiography and intravascular ultrasound (IVUS) were conducted immediately after AMS deployment and at 4 months. Eight patients who did not require repeat revascularization at 4 months underwent late angiographic and IVUS follow-up from 12 to 28 months. RESULTS: The AMS was well-expanded upon deployment without immediate recoil. The major contributors for restenosis as detected by IVUS at 4 months were: decrease of external elastic membrane volume (42%), extra-stent neointima (13%), and intra-stent neointima (45%). From 4 months to late follow-up, paired IVUS analysis demonstrated complete stent degradation with durability of the 4-month IVUS indexes. The neointima was reduced by 3.6 +/- 5.2 mm(3), with an increase in the stent cross sectional area of 0.5 +/- 1.0 mm(2) (p = NS). The median in-stent minimal lumen diameter was increased from 1.87 to 2.17 mm at long-term follow-up. The median angiographic late loss was reduced from 0.62 to 0.40 mm by quantitative coronary angiography from 4 months to late follow-up. CONCLUSIONS: Intravascular ultrasound imaging supports the safety profile of AMS with degradation at 4 months and maintains durability of the results without any early or late adverse findings. Slower degradation is warranted to provide sufficient radial force to improve long-term patency rates of the AMS.