Search PubMed⌕ Search

Biomedical subjects

Martin B Leon

Publications and source records attributed to Martin B Leon.

At least 109 records · Page 6Linked to original sources
PubMed2004

Advanced c-myc antisense (AVI-4126)-eluting phosphorylcholine-coated stent implantation is associated with complete vascular healing and reduced neointimal formation in the porcine coronary restenosis model.

An advanced six-ring morpholino backbone c-myc antisense (AVI-4126) was shown to inhibit c-myc expression and intimal hyperplasia after local catheter delivery in a porcine balloon injury model. The purpose of this study was to investigate the effects of an AVI-4126-eluting phosphorylcholine-coated (PC) stent on c-myc expression restenosis and vascular healing after stent implantation in porcine coronary arteries. PC stents were loaded with AVI-4126 using soak trap. Nine pigs underwent AVI-4126 PC coronary stent implantation (two stents/animal). Two to six hours postprocedure, three pigs were sacrificed and stented segments were analyzed by Western blot for c-myc expression. In chronic experiments, six pigs (12 stent sites) were sacrificed at 28 days following intervention and vessels were perfusion-fixed. High-performance liquid chromatography analysis of plasma samples showed minimal presence of the antisense. Western blot analysis of the stented vessels demonstrated inhibition of c-myc expression at 2 and 6 hr after procedure. Quantitative histologic morphometry showed that the neointimal area was significantly reduced (by 40%) in the antisense-coated group compared with control (2.3 +/- 0.7 vs. 3.9 +/- 0.8 mm(2), respectively; P = 0.0077). Immunostaining and electron microscopy demonstrated complete endothelialization, without fibrin deposition, thrombosis, or necrosis in all implanted stents. In the porcine coronary model, an advanced c-myc-eluting PC stent blocked c-myc expression and significantly inhibited myointimal hyperplasia and allowed complete reendothelialization and healing response.

Animals↗
PubMed2004

Favorable effect of gamma-radiation for in-stent restenosis: effect of diabetes on angiographic and clinical outcomes.

The purpose of this study was to examine the effect of vascular brachytherapy with gamma-radiation (gamma-RT) in patients with diabetes mellitus (DM) with coronary in-stent restenosis (ISR). In the Washington Radiation for In-Stent Restenosis (WRIST) trial, 130 patients with ISR were treated with (192)Ir or placebo. Of the patients enrolled, 44 (34%) had DM (18 of them treated with gamma-RT and 26 with placebo). Gamma-radiation therapy of ISR in diabetics resulted in similar procedural success and in-hospital outcome compared to nondiabetics. At 6-month follow-up, both DM and non-DM patients treated with gamma-RT had significantly lower target lesion revascularization (TLR), target vessel revascularization, and major adverse cardiac event rates compared to placebo. DM remains a powerful predictor of TLR and major adverse cardiac events even after treatment of ISR with gamma-RT.

Adult↗
PubMed2004

Contribution of early lumen loss after balloon angioplasty for in-stent restenosis to lumen loss at follow-up.

The treatment of in-stent restenosis using balloon angioplasty alone often produces excellent early results, but is associated with high rate of recurrence. Previous studies have demonstrated significant tissue reintrusion shortly after the treatment of in-stent restenosis with balloon angioplasty. The study was designed to elucidate the contribution of early lumen loss 6 hr after balloon angioplasty to lumen loss at follow-up. We prospectively performed quantitative coronary angiography and intravascular ultrasound in 12 patients with in-stent restenosis before intervention, after the final procedure, 6 hr later (5.6 +/- 1.4 hr), and at follow-up (7.7 +/- 2.3 months). Compared with immediately after balloon angioplasty, by 6 hr postintervention, the minimum lumen diameter (MLD) and lumen cross-sectional area had decreased significantly (2.48 +/- 0.44 to 2.01 +/- 0.57 mm, P = 0.01, and 7.0 +/- 1.2 to 5.5 +/- 1.4 mm2, P = 0.004, respectively). Furthermore, the MLD decreased further between 6 hr postintervention and long-term follow-up (2.01 +/- 0.57 to 1.55 +/- 0.64 mm; P = 0.001). Patients who showed recurrence of restenosis at follow-up had greater early lumen loss than patients without recurrence of restenosis (0.71 +/- 0.31 vs. 0.23 +/- 0.13 mm; P = 0.006). Diffuse lesions had greater early lumen loss compared to focal lesions (0.75 +/- 0.35 vs. 0.28 +/- 0.13 mm; P = 0.008). Early lumen loss is common after the treatment of in-stent restenosis by balloon angioplasty. Within the first 6 hr postintervention, 32% +/- 29% of acute lumen gain is lost, and early lumen loss contributed to 42% +/- 18% of total lumen loss at follow-up.

Aged↗
PubMed2004

Luminal narrowing due to intramural hematoma shift from left anterior descending coronary artery to left circumflex artery.

This case report demonstrates subacute luminal narrowing 20 days after balloon angioplasty in the left anterior descending coronary artery due to an intramural hematoma. Stenting was performed and resulted in side-branch compromise caused by squeezing the hematoma from the left anterior descending coronary artery into the left circumflex artery. Another stent was deployed to treat the stenosis in the left circumflex artery.

Adult↗
PubMed2004

Successful use of the frontrunner catheter in the treatment of in-stent coronary chronic total occlusions.

Percutaneous intervention of coronary chronic total occlusion (CTO) from in-stent restenosis (ISR) is hindered by difficulty to cross the lesion with conventional guidewires. This study describes the successful treatment of five cases of CTOs from ISR using the Frontrunner controlled blunt microdissection catheter. Four of the five cases had failed previous attempts of percutaneous intervention with conventional guidewires. The Frontrunner catheter successfully facilitated the placement of guidewire into the distal true lumen in all five cases. The median crossing time was 10 min. No subintimal delivery of guidewire or vascular perforation was observed. TIMI 3 flow was achieved in all target vessels after further balloon angioplasty or stenting. The Frontrunner device is a safe and effective tool in the treatment of CTOs from ISR.

Aged↗
PubMed2004

Impact of symptomatic peripheral arterial disease on 1-year mortality in patients undergoing percutaneous coronary interventions.

PURPOSE: To determine the impact of symptomatic peripheral arterial disease (PAD) on clinical outcomes in patients treated with percutaneous coronary interventions (PCI). METHODS AND RESULTS: Symptomatic PAD was identified in 1969 (18.9%) of 10440 consecutive patients undergoing PCI. Patients with PAD were older, more frequently female, and had smaller body surface area and more atherosclerotic risk factors, chronic renal insufficiency, and heart failure. Patients with PAD had lower rates of procedural success (94.2% versus 96.2%, p<0.0001) and higher rates of in-hospital complications, including all-cause mortality (2.1% versus 1.1%, p=0.0002), cardiac death (1.5% versus 0.7%, p=0.0009), urgent coronary artery bypass grafting (1.9% versus 1.2%, p=0.01), recurrent ischemia (5.6% versus 2.8%, p<0.0001), re-PCI to the target lesion (2.4% versus 1.1%, p<0.0001), stroke (0.6% versus 0.3%, p=0.0344), transient ischemic attack (0.4% versus 0.1%, p=0.01), femoral hematoma (10.3% versus 8.5%, p=0.01), retroperitoneal hematoma (0.8% versus 0.3%, p=0.009), limb ischemia (3.0% versus 0.7%, p<0.0001), gastrointestinal bleeding (1.9% versus 0.9%, p<0.0001), and blood transfusion (10.1% versus 5.2%, p<0.0001). At 1-year follow-up, patients with PAD had a higher mortality rate (13.6% versus 5.2%, p<0.0001), a higher rate of myocardial infarction (8.3% versus 6.5%, p=0.008), and also more target lesion (21.2% versus 19.8%, p=0.02) or target vessel revascularization (24.6% versus 21.2%, p=0.002). By multivariate analysis, PAD was an independent predictor of 1-year mortality (odds ratio 1.71, 95% confidence interval 1.42 to 2.07, p<0.0001). CONCLUSIONS: Nearly a fifth of patients undergoing PCI have symptomatic PAD. The presence of PAD is associated with lower rates of procedural success, higher rates of in-hospital and 1-year adverse events, and is independently associated with increased 1-year mortality.

Adult↗
PubMed2004

Update on sirolimus drug-eluting stents.

Percutaneous transluminal coronary angioplasty (PTCA) has become the main method of coronary revascularization. However, despite technical advancement, restenosis with incidence rate of 30 to 50% remains a major limitation to the long-term success of PTCA. The introduction of stents has significantly improved capability of interventional cardiology in treatment and prevention of restenosis. Recent experimental studies in animals, clinical studies in humans and multi-center randomized clinical trials with Sirolimus-eluting stents, have demonstrated a significant reduction in vasculoproliferative response with no intimal tissue growth. Moreover, no significant adverse clinical events have been reported at long-term follow-up and first studies that explored the potential of this technology for the treatment of in-stent restenosis demonstrated safety and efficacy. Although the first clinical experiences with drug-eluting stents have produced stunning results, there are a number of theoretical limitations to these devices, including: 1) limitations of drug loading capacity and 2) ability to control drug elution that could result in unfavorable pharmacokinetics. There are also questions about the durability of the polymer coatings (deformation under mechanical stress, gaps between metal and arterial wall, etc). The thickness of some coatings makes them unsuitable for very small vessels. Finally most biodegradable coatings are prone to chronic inflammation. Since only a polymer-coated bare metal stent remains following the drug's release, the potential for long term polymer biocompatibility problems remains a concern. The potential for some drugs to produce radiation-like effects such as "black holes", malapposed and naked struts and wall thinning are potentially the dark side of this technology and may contribute to late thrombosis, aneurysms or delayed restenosis. Long term clinical follow-up is necessary to assess the long term safety of this technology. There is a legitimate question as to whether drug-eluting stents will produce similar results across all patient subsets encountered in "real-life" interventional practice (e.g. long lesions, small diameter vessels, vein grafts, chronic total occlusions, bifurcated and ostial lesions). Cost-benefit issues also need to be addressed, especially because multivessel stenting and multistent usage is likely to increase.

Angioplasty, Balloon, Coronary↗
PubMed2003

Comparison of the angiographic outcomes after beta versus gamma vascular brachytherapy for treatment of in-stent restenosis.

This study was designed to compare the angiographic outcomes of beta versus gamma vascular brachytherapy (VBT). We reviewed the angiographic results of 636 lesions (212 that underwent beta and 212 that underwent gamma VBT, and 212 that received placebo) with native coronary in-stent restenosis matched for lesion length, vessel size, preprocedure minimum lumen diameter (MLD), and time to angiographic follow-up in the various randomized clinical trials and studies. Baseline lesion complexity was similar in these 3 groups. Final MLD was smaller in the beta VBT group than in the gamma VBT or placebo group. At follow-up, beta and gamma VBT significantly reduced both angiographic restenosis (34.4% for beta VBT, 26.4% for gamma VBT, and 50.9% in the placebo group; p <0.0001) and recurrent lesion length (9.2 mm for beta VBT, 8.4 mm for gamma VBT, and 15.5 mm placebo, p <0.0001) compared with placebo. Gamma VBT was associated with a greater reduction in restenosis outside the stent than beta VBT. By multivariable analysis, independent angiographic predictors of treated segment restenosis included beta or gamma VBT, lesion length, and vessel size. In matched lesions, beta and gamma VBT achieved similar reductions in treated segment restenosis and recurrent lesion length compared with placebo.

Adult↗
PubMed2003

Increased CK-MB release is a "trade-off" for optimal stent implantation: an intravascular ultrasound study.

OBJECTIVES: We sought to determine the impact of aggressive stent expansion on creatine kinase-MB isoenzyme (CK-MB) release and clinical restenosis. BACKGROUND: Elevation of CK-MB after percutaneous coronary interventions has been associated with late mortality. METHODS: We identified 989 consecutive patients who underwent intravascular ultrasound-guided stenting of 1,015 coronary lesions. Patients were divided into three groups according to stent expansion, defined as the ratio of final lumen over the reference lumen cross-sectional areas: Group 1 (ratio <70%, n = 117 patients with 126 lesions); Group 2 (ratio 70% to 100%, n = 551 patients with 562 lesions); Group 3 (ratio >100%, n = 321 patients with 327 lesions). RESULTS: The peak CK-MB values increased significantly with increasing stent expansion: CK-MB = 3 to 5x normal occurred 16%, 18%, and 25% in Groups 1, 2, and 3, respectively, p = 0.02; CK-MB >5 times normal occurred 9%, 13%, and 16% respectively, p = 0.02. Conversely, at one year follow-up there was a stepwise decrease in target lesion revascularization (11% vs. 19% and 17%, respectively, p = 0.04) and major adverse cardiac events with increasing stent expansion. In addition, there was a trend toward lower mortality in Group 3 (9% vs. 4.4% vs. 4.0%, p = 0.07). CONCLUSIONS: Intravascular ultrasound-guided stent overexpansion (final lumen greater than reference lumen cross-sectional area) is accompanied by a higher periprocedural CK-MB release but a lower target lesion revascularization and a trend toward lower mortality at one year. Increased periprocedural CK-MB release appears as a trade-off for optimal stent implantation and lower clinical restenosis.

Cineangiography↗
PubMed2003

Acute and long-term outcomes of cutting balloon angioplasty followed by gamma brachytherapy for in-stent restenosis.

In-stent restenosis lesions were divided into 2 groups according to the use of cutting balloon (n = 76) or conventional balloon angioplasty (n = 407) before gamma-brachytherapy. Cutting balloon angioplasty, compared with conventional balloon angioplasty, in patients undergoing gamma-brachytherapy for in-stent restenosis is associated with less requirement for new stents (11% vs 22%, p = 0.02) but similar target vessel revascularization (35.1% vs 29.8%, p = 0.4) at follow-up.

Aged↗
PubMed2003

Optimal final lumen area and predictors of target lesion revascularization after stent implantation in small coronary arteries.

Despite similar early clinical events, patients who undergo treatment of small vessels are at an increased risk for target lesion revascularization (TLR) after coronary artery stenting. We sought to determine predictors of TLR after stent implantation in small coronary arteries. We identified 423 consecutive patients who underwent intravascular ultrasound (IVUS)-guided small vessel stenting procedures in 465 coronary lesions with an angiographic reference vessel diameter of <2.75 mm. Patients were divided into 2 groups based on a final IVUS lumen area of < or =6.0 mm2 (n=345 lesions, group I) and >6.0 mm2 (n=115, group II). Baseline patient characteristics and in-hospital outcomes were similar between the 2 groups, except for a higher rate of restenotic lesions in group I and bifurcation lesions in group II. Group I had higher TLR rates at 1 year compared with group II patients (39% vs 26%, p = 0.02). The TLR rate appeared to decrease with greater stent expansion, especially at >90% of the reference vessel area, as assessed by IVUS. By multivariate analysis, an IVUS final stent area of < or =6 mm2, diabetes, absence of prior myocardial infarction, and history of intervention were independent predictors of 1-year TLR in this population. Final stent area of >6.0 mm2 and greater stent expansion were associated with a decrease in TLR. Therefore, there does not appear to be any "downside" to aggressive stent implantation strategies in small vessels. In contrast, IVUS allows maximization of final lumen dimensions to minimize clinical restenosis.

Aged↗
PubMed2003

Usefulness of the angiographic pattern of in-stent restenosis in predicting the success of gamma vascular brachytherapy.

The prognostic role of the angiographic pattern of in-stent restenosis after gamma vascular brachytherapy was assessed from a pooled data set of 4 clinical trials comprising 295 irradiated patients with matched baseline and follow-up angiograms. The binary angiographic restenosis rate increased with worsening in-stent restenosis patterns; however, target lesion revascularization and major adverse cardiac event rates increased for focal, diffuse, and proliferative patterns of in-stent restenosis but not for total occlusions.

Aged↗
PubMed2003

Intravascular ultrasound assessment of ulcerated ruptured plaques: a comparison of culprit and nonculprit lesions of patients with acute coronary syndromes and lesions in patients without acute coronary syndromes.

BACKGROUND: It is not clear why some plaque ruptures lead to acute coronary syndromes (ACS) but others do not. METHODS AND RESULTS: We analyzed 80 plaque ruptures in 74 patients and compared culprit lesions of ACS patients with nonculprit lesions of ACS patients and lesions of non-ACS patients; both culprit and nonculprit plaque ruptures were studied in 6 of 54 ACS patients. Intravascular ultrasound findings suggesting thrombus were observed more frequently in culprit lesions of ACS patients (n=35) compared with nonculprit lesions of ACS patients (n=19) and lesions of non-ACS patients (n=26): 60% versus 32% versus 8% (P<0.001). At the minimal lumen site, smaller lumen areas (3.3+/-1.5 versus 5.4+/-2.6 versus 6.1+/-2.0 mm2, P<0.001) and greater area stenosis (61+/-15% versus 50+/-14% versus 46+/-18%, P=0.002) and plaque burden (80+/-8% versus 71+/-8% versus 69+/-10%, P<0.001) were observed in culprit lesions of ACS patients compared with nonculprit lesions of ACS patients and lesions of non-ACS patients. Lesions were longer (18.7+/-6.4 versus 154.9+/-6.1 versus 12.0+/-4.9 mm, P<0.001) and rupture site remodeling indices were greater (1.26+/-0.21 versus 1.24+/-0.21 versus 1.09+/-0.05, P=0.002). Independent predictors of culprit plaque ruptures in ACS patients were smaller minimum lumen areas (P=0.02) and presence of thrombus (P=0.01). CONCLUSIONS: Ruptured plaques in culprit lesions of ACS patients have smaller lumens; greater plaque burdens, area stenosis, and remodeling indices; and more thrombus. Plaque rupture itself does not lead to symptoms. The association of plaque rupture with a smaller lumen area and/or thrombus formation causes lumen compromise and leads to symptoms.

Acute Disease↗
PubMed2003

Comparison of effect of glycoprotein IIb/IIIa inhibitors during percutaneous coronary interventions on risk of hemorrhagic stroke in patients >or=75 years of age versus those <75 years of age.

Of 1,369 consecutive patients who underwent stent-assisted coronary angioplasty and who were treated with glycoprotein IIb/IIIa inhibitors during these procedures, 17.5% were >or=75 years of age. Compared with patients <75 years old, those >or=75 years of age had similar procedural and in-hospital outcomes but significantly higher rates of hemorrhagic stroke (0.08% vs 1.2%, p <0.001).

Age Factors↗
PubMed2003

Sirolimus-eluting stents versus standard stents in patients with stenosis in a native coronary artery.

BACKGROUND: Preliminary reports of studies involving simple coronary lesions indicate that a sirolimus-eluting stent significantly reduces the risk of restenosis after percutaneous coronary revascularization. METHODS: We conducted a randomized, double-blind trial comparing a sirolimus-eluting stent with a standard stent in 1058 patients at 53 centers in the United States who had a newly diagnosed lesion in a native coronary artery. The coronary disease in these patients was complex because of the frequent presence of diabetes (in 26 percent of patients), the high percentage of patients with longer lesions (mean, 14.4 mm), and small vessels (mean, 2.80 mm). The primary end point was failure of the target vessel (a composite of death from cardiac causes, myocardial infarction, and repeated percutaneous or surgical revascularization of the target vessel) within 270 days. RESULTS: The rate of failure of the target vessel was reduced from 21.0 percent with a standard stent to 8.6 percent with a sirolimus-eluting stent (P<0.001)--a reduction that was driven largely by a decrease in the frequency of the need for revascularization of the target lesion (16.6 percent in the standard-stent group vs. 4.1 percent in the sirolimus-stent group, P<0.001). The frequency of neointimal hyperplasia within the stent was also decreased in the group that received sirolimus-eluting stents, as assessed by both angiography and intravascular ultrasonography. Subgroup analyses revealed a reduction in the rates of angiographic restenosis and target-lesion revascularization in all subgroups examined. CONCLUSIONS: In this randomized clinical trial involving patients with complex coronary lesions, the use of a sirolimus-eluting stent had a consistent treatment effect, reducing the rates of restenosis and associated clinical events in all subgroups analyzed.

Aged↗
PubMed2003

Safety of an aspirin-alone regimen after intracoronary stenting with a heparin-coated stent: final results of the HOPE (HEPACOAT and an Antithrombotic Regimen of Aspirin Alone) study.

BACKGROUND: Stent thrombosis is an infrequent complication of intracoronary stenting that often has devastating clinical consequences. This study assesses the additional benefit of heparin coating with the BX VELOCITY Balloon-Expandable Stent with HEPACOAT, Carmeda end-point attached heparin (HEPACOAT) in patients with de novo or restenotic native coronary artery lesions treated with aspirin monotherapy after optimal stenting. METHODS AND RESULTS: This was a multicenter, prospective, nonrandomized, pilot study. Two hundred patients (69% men; mean age, 64.1+/-11.2 years) meeting the eligibility criteria were treated with the HEPACOAT stent and aspirin alone after stenting. Any other antiplatelet or anticoagulation therapy was not permitted. Procedural success was achieved in all patients. There were 3 postprocedural non-Q-wave myocardial infarctions. The primary end point of stent thrombosis at 30 days occurred in 2 of 200 patients (1%): in one after blunt chest trauma and in the other in the setting of essential thrombocytosis. Major adverse cardiac events (death, myocardial infarction, target lesion revascularization, and coronary artery bypass grafting) were observed at 30 days in 5 of 200 (2.5%) patients. CONCLUSIONS: The BX VELOCITY stent with HEPACOAT and aspirin alone after the procedure was safe in select patients with de novo or restenotic lesions in native coronary arteries. Heparin coating provides additional protection against stent thrombosis.

Angioplasty, Balloon, Coronary↗
PubMed2003

Comparison of in-hospital and one-year outcomes after multiple coronary arterial stenting in patients > or =80 years old versus those <80 years old.

The present study evaluated in-hospital and 1-year outcomes after multivessel stenting in patients aged > or =80 (75 patients, 241 lesions) and <80 years (894 patients, 2,678 lesions). Despite a high technical success rate of multivessel stenting, octogenarians had higher in-hospital cardiac and noncardiac complication rates and a higher mortality rate at 1-year clinical follow-up compared with their younger counterparts.

Aged↗