Incidence and predictors of restenosis after successful primary coronary angioplasty for acute myocardial infarction: the importance of age and procedural result

Photodynamic therapy of balloon-injured rat carotid arteries using indocyanine green

Photodynamic therapy (PDT) has been used to inhibit intimal hyperplasia in injured arteries. Because of the limited tissue penetration of visible light, an endovascular light source with a guided wire is often required for effective treatment. Indocyanine green (ICG), a near-infrared (NIR) photosensitizer, has been used in PDT for cancers. An extracorporeal light source may be used for shallow tissue because of the better tissue penetration of NIR light. The aim of this study was to evaluate the effect of ICG-PDT using extracorporeal NIR light on the inhibition of intimal hyperplasia in balloon-injured carotid arteries. A balloon injury (BI) model was used to induce intimal hyperplasia of carotid artery. Sprague-Dawley rats were divided into control, BI, BI + 1 × PDT, and BI + 2 × PDT groups. The control group underwent a sham procedure. PDT was performed 7 days after BI. In the BI + 1 × PDT group, ICG was administered 1 h before light irradiation. External illumination with 780-nm light-emitting diode light at a fluence of 4 J/cm² was applied. For the BI + 2 × PDT group, PDT was performed again at day 7, following the first PDT. Hematoxylin and eosin (H & E) staining was performed to assess vessel morphology. Arterial wall thickness was significantly larger in the BI group compared with the control group. ICG-PDT significantly reduced arterial wall thickness compared with the BI group. Repeated PDT further decreased arterial wall thickness to the level of the control group. These findings indicate a promising approach for the treatment of restenosis of carotid arteries.

Short-term follow-up results of drug-eluting stenting in premature coronary artery disease patients with multiple atherosclerotic risk factors

BACKGROUND

Premature coronary artery disease (CAD) is a special entity with a strong link to familial hypercholesterolemia, family history of premature CAD, or multiple coexistent atherosclerotic risk factors. Drug-eluting stenting (DES), including paclitaxel-eluting stenting (PES) and sirolimus-eluting stenting (SES), has been proven to have a lower restenotic rate. However, to date, few studies have investigated the clinical and angiographic results of DES in premature CAD patients.

METHODS

Between February 2004 and October 2005, premature CAD patients, defined as those younger than 50 years of age, who were treated with DES in our medical center were all retrospectively enrolled. Their baseline clinical characteristics, clinical outcome and angiographic follow-up results were analyzed.

RESULTS

A total of 26 patients (M/F: 23/3) were enrolled, with a mean age of 44+/-6 years (range, 24-50 years). Conventional atherosclerotic risk factors were prevalent in this study group, including diabetes mellitus (35%), hypertension (35%), hyperlipidemia (54%) and smoking (73%). Moreover, there was 1 homozygous and 1 heterozygous familial hypercholesterolemia case in our study group. In terms of angiographic results, there were 40 target lesions in 34 target vessels. Forty DES (39 PES, 1 SES) were implanted with a median stent diameter of 3 mm and median length of 24 mm. The clinical follow-up was counted up to May 2006, with a mean follow-up duration of 540+/-168 days; 11 (42%) patients had a second angiogram during the follow-up period (200+/-98 days after DES). None of the patients had target lesion revascularization (TLR). In addition, there was no difference in TLR or stent thrombosis between patients with or without acute coronary syndrome.

CONCLUSION

Based on our single-center experience, DES had good short-term follow-up results for a premature CAD group with diverse and multiple atherosclerotic risk factors.

Time to reperfusion in acute myocardial infarction. It is time to reduce it!

BACKGROUND AND OBJECTIVES

Mortality from ST-segment elevation myocardial infarction remains high, with most deaths occurring before hospital admission. Despite effective pre- and in-hospital reperfusion strategies becoming standard over the past 2 decades, time-to-admission and time-to-treatment remain prolonged. We reviewed temporal trends in these times in published clinical trials.

METHODS

All major randomized clinical trials reporting on reperfusion strategies for acute myocardial infarction published between 1993 and 2003 were evaluated. Strategies included pre- and in-hospital thrombolysis, primary percutaneous coronary intervention (pPCI) with or without transfer, and "facilitated" PCI. We generated overall estimates of time-to-admission, time-to-treatment, door-to-balloon (DTB), and door-to-needle (DTN) times and evaluated temporal trends in the length of time-to-admission and time-to-treatment.

RESULTS

In studies that evaluated only in-hospital thrombolysis, the time-to-admission was 149 +/- 45 minutes; the mean time-to-treatment was 181 +/- 29 minutes. In studies that considered only in-hospital pPCI (without transfer), the mean time-to-admission was 153 +/- 41 minutes; the mean time-to-treatment was 234 +/- 43 minutes. In studies that compared in-hospital pPCI with in-hospital thrombolytic therapy, the mean time-to-admission was 155 +/- 47 and 150 +/- 48 minutes, respectively. The DTN time was 65 +/- 10 minutes, whereas DTB time was 81 +/- 39 minutes. In other trials evaluating in-hospital thrombolysis and pPCI with transfer to a referral center, the time-to-admission in subjects treated with thrombolysis (n = 1345) was 127 +/- 32 minutes vs 131 +/- 36 minutes for pPCI (n = 1528). For in-hospital thrombolysis, time-to-treatment was 151 +/- 23 minutes vs 203 +/- 15 minutes for pPCI patients with transfer. The DTN time in the thrombolysis group was 44 +/- 28 minutes as compared with DTB time of 78 +/- 38 minutes in the pPCI group. Throughout the last decade, time-to-admission decreased significantly (P = .02) but time-to-treatment remained unchanged (P = .38) for patients undergoing thrombolysis. In the pPCI arm, time-to-admission remained unchanged (P = .11) but a insignificant trend toward reduction was demonstrated in time-to-treatment (P = .11).

CONCLUSION

Time-to-admission and time-to-treatment for ST-segment elevation myocardial infarction are still prolonged. Resources should be directed to early recognition of the acute myocardial infarction, improved utilization of emergency services for transportation, and prehospital diagnosis and triaging. Ambulances equipped with wireless capability to transmit electrocardiograms to the on-call cardiologist seem to be promising tools to achieve earlier diagnosis and triaging with high diagnostic sensitivity and specificity.

Medium-Term Prognosis of Young Japanese Adults Having Acute Myocardial Infarction

BACKGROUND

Data on the medium- and long-term prognosis of young Japanese patients with acute myocardial infarction (AMI) are still lacking.

METHODS AND RESULTS

In the present study, 1,458 AMI patients were enrolled in the AMI-Kyoto Multi-Center Risk Study between January 2000 and December 2003. Of these, clinical characteristics and medium-term prognosis were retrospectively compared in 21 young patients < 40 years (young group), and 190 non-young patients 60-70 years old (non-young group) who could be followed after hospital discharge. The young group was all male and had higher prevalence of current smoking and greater body mass index, but previous myocardial infarction (MI) and hypertension were more prevalent in the non-young group. The young group had a higher prevalence of single-vessel disease and a lesser incidence of left circumflex coronary artery as the culprit lesion. The acquisition rates of Thrombolysis In Myocardial Infarction 3 flow after primary percutaneous coronary intervention did not differ between the 2 groups, but the data of maximal creatine kinase was significantly higher in the young group. During the follow-up period (average 2.42 years for young, 2.37 years for non-young), survival and event-free survival rates and incidence of major adverse cardiac events (MACE) did not differ between the 2 groups. The predictor of MACE during follow-up period was the presence of multivessel disease in the young group, whereas the presence of multivessel disease, history of previous MI and longer hospitalization were the predictors of MACE in the non-young group.

CONCLUSIONS

These results suggest that the medium-term prognosis in young AMI patients is comparable to that of non-young AMI patients in Japan.

Interventional Treatment for Very Young Adults With Acute Myocardial Infarction: Clinical Manifestations and Outcome

Direct percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) is now established as a standard therapy for older patients. However, experience with PCI in very young adults with AMI has been limited. In this report we retrospectively evaluated the effectiveness of PCI for very young adults with AMI and estimated their clinical characteristics and outcome. Of the 502 patients with AMI, 5 were 35 years old or younger (1.0%) during a period of 4 years (2000--2004). We assessed the utility of PCI in these five consecutive patients under the age of 35 presenting with a first AMI. Five AMI patients, ranging in age from 20 to 34 years (median, 27+/-5 years) underwent direct PCI for the culprit lesions. The lesions targeted for PCI were located in the left anterior descending artery in 3 patients and in the right coronary artery in 2 patients. One patient had a past history of Kawasaki disease (KD). In all of the patients, PCI were angiographically effective at the acute phase without complication. In hospital course, a subacute stent thrombosis occurred in one patient. Follow-up angiograms performed 6 months after the procedure revealed no restenosis, but identified a new coronary aneurysm in one patient with a past history of KD and a regressed giant coronary aneurysm probably due to atypical KD in another patient, which were confirmed by intravascular ultrasound. There was one death ascribed to heart failure 8 months after the initial PCI. The findings of this report suggest that PCI for very young adults with AMI can be safe and effective in the short-term.

Acute Myocardial Infarction in Young Japanese Adults Clinical Manifestations and In-Hospital Outcome

BACKGROUND

The prevalence and clinical manifestations of acute myocardial infarction (AMI) in young patients in Japan have not been fully investigated.

METHODS AND RESULTS

In the present study, 1651 AMI patients were enrolled in the AMI-Kyoto Multi-Center Risk Study between January 2000 and June 2004. Of these, the clinical background, risk factors, angiographic findings, acute results of primary percutaneous coronary intervention (PCI) and in-hospital outcomes for 27 young patients <40 (young group), and 338 non-young patients 60<or=, <70 years old (non-young group) were retrospectively compared. The young AMI patients were all male. Current smoking, hypercholesterolemia and family history were the most common risk factors in young patients, while hypertension and diabetes mellitus were more prevalent in non-young patients. Young patients had a higher prevalence of single-vessel disease and a lesser incidence of left circumflex coronary artery as a culprit lesion. The young group had high acquisition rates of Thrombolysis In Myocardial Infarction 3 flow just after primary PCI (95.8%) and no in-hospital deaths, which was not significantly different from the non-young group.

CONCLUSIONS

These results suggest that young AMI patients have different clinical characteristics from those in non-young AMI patients, and acute results of primary PCI and in-hospital prognosis in young AMI patients are comparable to those in non-young AMI patients in Japan.

Vascular restenosis - striving for therapy

Restenosis is the limiting entity following coronary angioplasty. It is associated with significant morbidity, mortality and cost, and thus represents a major clinical and economical problem. Despite technical improvements, restenosis after conventional balloon angioplasty occurs in 30 - 60% of cases. Coronary stenting was able to reduce the incidence by approximately 30%; nevertheless, some 250,000 patients experience in-stent restenotic lesions/year worldwide. In-stent restenosis has been recognised as very difficult to manage, with a repeat restenosis rate of 50%, regardless of the angioplasty device used. So far, only vascular brachytherapy has convincingly reduced the incidence of repeat in-stent restenosis (by 50%) and thus, has emerged as the gold standard of therapy. The introduction of drug-eluting stents has shown a great deal of promise for the treatment of both de novo and restenotic lesions, with reported restenosis rates of < 10%, and benefit for virtually all patient subsets at a higher risk of restenosis. This review outlines the pathophysiology, epidemiology and predictors of the restenosis process, and places emphasis on the various treatment options for its prevention and therapy.

Blockade of vascular smooth muscle cell proliferation and intimal thickening after balloon injury by the sulfated oligosaccharide PI-88: phosphomannopentaose sulfate directly binds FGF-2, blocks cellular signaling, and inhibits proliferation

Percutaneous transluminal coronary angioplasty is a frequently used interventional technique to reopen arteries that have narrowed because of atherosclerosis. Restenosis, or renarrowing of the artery shortly after angioplasty, is a major limitation to the success of the procedure and is due mainly to smooth muscle cell accumulation in the artery wall at the site of balloon injury. In the present study, we demonstrate that the antiangiogenic sulfated oligosaccharide, PI-88, inhibits primary vascular smooth muscle cell proliferation and reduces intimal thickening 14 days after balloon angioplasty of rat and rabbit arteries. PI-88 reduced heparan sulfate content in the injured artery wall and prevented change in smooth muscle phenotype. However, the mechanism of PI-88 inhibition was not merely confined to the antiheparanase activity of this compound. PI-88 blocked extracellular signal-regulated kinase-1/2 (ERK1/2) activity within minutes of smooth muscle cell injury. It facilitated FGF-2 release from uninjured smooth muscle cells in vitro, and super-released FGF-2 after injury while inhibiting ERK1/2 activation. PI-88 inhibited the decrease in levels of FGF-2 protein in the rat artery wall within 8 minutes of injury. PI-88 also blocked injury-inducible ERK phosphorylation, without altering the clotting time in these animals. Optical biosensor studies revealed that PI-88 potently inhibited (Ki 10.3 nmol/L) the interaction of FGF-2 with heparan sulfate. These findings show for the first time the capacity of this sulfated oligosaccharide to directly bind FGF-2, block cellular signaling and proliferation in vitro, and inhibit injury-induced smooth muscle cell hyperplasia in two animal models. As such, this study demonstrates a new role for PI-88 as an inhibitor of intimal thickening after balloon angioplasty. The full text of this article is available online at http://www.circresaha.org.

Acute myocardial infarction in the young--The University of Michigan experience

BACKGROUND

The purpose of this study was to assess frequency, risk factors, treatment, and complications of very young patients with acute myocardial infarction (MI) at the University of Michigan Medical Center (UMMC).

METHODS

From a database of 976 consecutive patients admitted to the UMMC with acute MI between 1995 and 1998, we compared care and outcomes of patients divided into 3 age categories: <46 years, 46-54 years, and >54 years. Risk factors, presenting symptoms, type of MI, management, complications, and hospital outcomes of the 3 groups were evaluated.

RESULTS

Young patients represented >10% of all patients with acute MI, and >25% of these individuals were women, a number considerably higher than seen in previous studies. This group of young patients was more likely to have Q-wave MI and risk factors such as family history and tobacco use and less likely to have a history of angina. Although all 3 groups received similar inpatient treatment, there was more attention paid to risk factor modification such as smoking cessation and referral to cardiac rehabilitation in younger individuals. Young patients had fewer in-hospital complications and a lower mortality rate.

CONCLUSIONS

At the University of Michigan, >1 in 10 with acute MI is <46 years old. Data suggest that current management and aggressive risk factor modification are quite good in this particular group, and overall the mortality rate is very low.

Long term outcome and cost-effectiveness of stenting versus balloon angioplasty for acute myocardial infarction

OBJECTIVE

To investigate the long term clinical outcome and cost-effectiveness of stenting compared with balloon angioplasty in patients with acute myocardial infarction.

METHODS

Patients with acute myocardial infarction were randomly allocated to primary stenting (112) or balloon angioplasty (115). The primary end point was the cumulative first event rate of death, non-fatal reinfarction, or target vessel revascularisation. Secondary end points were restenosis at six months and the cost-effectiveness at follow up.

RESULTS

After 24 months, the combined clinical end point of death/reinfarction was 4% after stenting and 11% after balloon angioplasty (p = 0.04). Subsequent target vessel revascularisation was necessary in 15 patients (13%) after stenting and in 39 (34%) after balloon angioplasty (p < 0.001). The cumulative cardiac event-free survival rate was also higher after stenting (84% v 62%, p < 0.001). The angiographic restenosis rate after stenting was less than after balloon angioplasty (12% v 34%, p < 0.001). Despite the higher initial costs of stenting (Dfl 21 484 v Dfl 18 625, p < 0.001), the cumulative costs at 24 months were comparable with those of balloon angioplasty (Dfl 31 423 v Dfl 32 933, p = 0.83).

CONCLUSIONS

Compared with balloon angioplasty, primary stenting for acute myocardial infarction results in a better long term clinical outcome without increased cost.

First human transvenous coronary angiography at the European Synchrotron Radiation Facility

The first operation of the European Synchrotron Radiation Facility (ESRF) medical beamline is reported in this paper. The goal of the angiography project is to develop a reduced risk imaging technique, which can be used to follow up patients after coronary intervention. After the intravenous injection of a contrast agent (iodine) two images are produced with monochromatic beams, bracketing the iodine K-edge. The logarithmic subtraction of the two measurements results in an iodine enhanced image, which can be precisely quantified. A research protocol has been designed to evaluate the performances of this method in comparison with the conventional technique. Patients included in the protocol have previously undergone angioplasty. If a re-stenosis is suspected, the patient is imaged both at the ESRF and at the hospital with the conventional technique, within the next few days. This paper reports the results obtained with the first patients. To date, eight patients have been imaged and excellent image quality was obtained.

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.