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Biomedical subjects

Martin B Leon

Publications and source records attributed to Martin B Leon.

At least 19 recordsLinked to original sources
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↗
PubMed2003

Usefulness of a cobalt chromium coronary stent alloy.

The cobalt chromium Guidant Multi-Link Vision coronary stent was deployed in 267 patients as part of a multicenter international registry. Major adverse cardiovascular events were infrequent, and late (180 days) quantitative angiography demonstrated binary (>50%) in-stent restenosis in 15.7% of patients. This registry establishes the safety and efficacy of this alloy as a coronary stent platform.

Adult↗
PubMed2003

Long-term follow-up of patients after gamma intracoronary brachytherapy failure (from GAMMA-I, GAMMA-II, and SCRIPPS-III).

We report the long-term outcome of 225 patients who failed gamma-brachytherapy for in-stent restenosis. Total adverse events, target vessel revascularization, and myocardial infarction were higher after repeat percutaneous coronary intervention versus coronary artery bypass grafting. Therefore, coronary artery bypass grafting may be the preferable first-line therapy in these patients until other therapies (i.e., drug-eluting stents) are available. Shorter time from brachytherapy to radiation failure and late thrombosis after brachytherapy were independent predictors of adverse events.

Brachytherapy↗
PubMed2003

Correlation of coronary arterial remodeling determined by intravascular ultrasound with angiographic diameter reduction of 20% to 60%.

Negative remodeling is commonly observed in stenotic coronary lesions. It is unknown whether negative remodeling is an early or late event. This study was designed to elucidate when negative remodeling occurs in the development of coronary stenosis. Remodeling was assessed by preintervention intravascular ultrasound in 104 native coronary lesions with intermediate stenosis (20% to 60% of diameter stenosis measured by quantitative coronary angiography). Positive remodeling was defined as lesion external elastic membrane (EEM) cross-sectional area (CSA) greater than the proximal reference, intermediate remodeling as lesion EEM CSA between those of the proximal and distal references, and negative remodeling as lesion EEM CSA less than the distal reference. Positive, intermediate, and negative remodeling were observed in 18%, 32%, and 50%, respectively, of lesions with intermediate stenosis. Lesions with negative and intermediate remodeling had more hard plaque compared with those with positive remodeling (79% vs 70% vs 42%, p = 0.02). Calcium was more frequent in lesions with negative and intermediate remodeling than in those with positive remodeling (52% vs 55% vs 16%, p = 0.01). Lesions with negative remodeling had smaller EEM CSA (11.5 +/- 5.2 vs. 13.7 +/- 3.4 vs 14.5 +/- 5.6 mm(2), p = 0.03) and less plaque (7.9 +/- 4.6 vs 10.8 +/- 3.4 vs 10.8 +/- 4.9 mm(2), p = 0.004) compared with positive and intermediate remodeling lesions, although lumen CSA (3.7 +/- 1.7 vs 2.8 +/- 0.8 vs 3.6 +/- 1.3 mm(2), p = 0.1) and area stenosis (57 +/- 15% vs 59 +/- 14% vs 56 +/- 10%, p = 0.7) were similar. Negative remodeling is frequently observed in lesions with intermediate stenosis. This suggests that negative remodeling occurs early in lesion formation.

Aged↗
PubMed2003

Intravascular brachytherapy for native coronary ostial in-stent restenotic lesions.

OBJECTIVES: We analyzed the effects of vascular brachytherapy (VBT) on ostial in-stent restenosis (ISR). BACKGROUND: In-stent restenosis has a high recurrence rate after percutaneous reintervention. The recurrence rate of ostial ISR lesions and the impact of VBT remain unknown. METHODS: We evaluated 133 patients with native coronary ostial ISR from a pooled database of 990 patients enrolled in randomized VBT trials. Independent quantitative angiography was performed at baseline and follow-up in 45 gamma, 27 beta, and 61 placebo patients. RESULTS: Binary restenosis was significantly higher in placebo than radiated patients (75.4% vs. 17.8% in gamma vs. 22.2% in beta, p < 0.0001). The treatment effect of both gamma (odds ratio [OR] 0.06; 95% confidence interval [CI] 0.02 to 0.17) and beta VBT (OR 0.10; 95% CI 0.03 to 0.31) was maintained after controlling for differences in baseline lesion length. Proximal and distal radiation edge restenosis rates were similar among the groups. Vascular brachytherapy of true aorto-ostial lesions (n = 34) was similarly beneficial: restenosis rates of placebo versus gamma or beta patients of 83.3% versus 6.7% versus 28.6%, p = 0.0002. CONCLUSIONS: Conventional treatment of ostial ISR is associated with a recurrence rate of over 75%. Vascular brachytherapy with either gamma or beta sources results in significant and similar reductions in restenosis compared with placebo. Similar benefits after VBT prevail in true aorto-ostial lesions.

Aorta↗
PubMed2003

Catheter-based autologous bone marrow myocardial injection in no-option patients with advanced coronary artery disease: a feasibility study.

OBJECTIVES: We conducted a pilot study to evaluate the feasibility of transendocardial delivery of autologous bone marrow (ABM) strategy in patients with severe symptomatic chronic myocardial ischemia not amenable to conventional revascularization. BACKGROUND: Transendocardial injection of ABM cells appears to enhance perfusion of ischemic porcine myocardium. METHODS: Ten patients underwent transendocardial injection of freshly aspirated and filtered unfractionated ABM using left ventricular electromechanical guidance. Twelve injections of 0.2 ml each were successfully delivered into ischemic noninfarcted myocardium pre-identified by single-photon emission computed tomography perfusion imaging. RESULTS: Autologous bone marrow injection was successful in all patients and was associated with no serious adverse effects; in particular, there was no arrhythmia, evidence of infection, myocardial inflammation, or increased scar formation. Two patients were readmitted for recurrent chest pain. At three months, Canadian Cardiovascular Society angina score significantly improved (3.1 +/- 0.3 vs. 2.0 +/- 0.94, p = 0.001), as well as stress-induced ischemia occurring within the injected territories (2.1 +/- 0.8 vs. 1.6 +/- 0.8, p < 0.001). Treadmill exercise duration, available in nine patients, increased, but the change was not significant (391 +/- 155 vs. 485 +/- 198, p = 0.11). CONCLUSIONS: This study provides preliminary clinical data indicating feasibility of catheter-based transendocardial delivery of ABM to ischemic myocardium.

Bone Marrow Transplantation↗
PubMed2003

Effect of percutaneous coronary interventions for in-stent restenosis in degenerated saphenous vein grafts without distal embolic protection.

OBJECTIVES: This study was designed to investigate the impact of percutaneous coronary interventions (PCIs) in degenerated saphenous vein grafts (SVGs) without distal embolic protection. BACKGROUND: Distal embolic protection devices have been shown to reduce the incidence of no reflow/slow flow during PCI of de novo lesions in degenerated SVGs. It is unclear whether PCI of in-stent restenosis (ISR) lesions in degenerated SVGs is associated with no reflow/slow flow and whether distal embolic protection is beneficial in these cases as well. METHODS: We studied 54 consecutive patients with treated ISR lesions in degenerated SVGs who underwent PCI without distal embolic protection in a single center. Procedural and in-hospital outcomes were examined. The average age was 71 +/- 8 years; 32% of the patients had diabetes. The mean lesion length was 13 +/- 6 mm and the procedural success rate was 98% (53/54). Cutting balloon angioplasty was used in 46% (25/54) of cases, and a new stent was inserted in 46% (25/54) of patients. Gamma brachytherapy was performed in 19% (10/54) of patients. During the procedure there were no episodes of no reflow/slow flow, and there were no patients with in-hospital Q-wave or non-Q-wave myocardial infarction. There was one in-hospital noncardiac death. CONCLUSIONS: In this consecutive series of patients with ISR of degenerated SVGs undergoing PCI without distal protection, there were no episodes of slow flow/no reflow and no procedure-related myocardial infarctions. It appears that distal embolic protection may not be necessary during PCI of ISR lesions in degenerated SVGs.

Aged↗
PubMed2003

Intracoronary radiation to treat in-stent restenosis in six cardiac transplant patients.

Transplant vasculopathy significantly limits the survival of cardiac transplant patients and occurs in 50% of patients by 5 years posttransplant. We report our experience with six cardiac transplant patients who underwent intracoronary brachytherapy for in-stent restenosis. At four centers, six patients underwent intracoronary radiation for in-stent restenosis. All patients received extended antiplatelet therapy with clopidogrel and aspirin. Follow-up angiography was performed in all patients. Two of the six patients underwent subsequent target lesion revascularization. Patient 1 presented with total occlusion of her radiated lesion. She had a complex procedure requiring stenting for a dissection after the radiation dwell. Patient 2 had high-grade restenosis following brachytherapy. Patient 3 had a 50% restenotic lesion. Patients 4, 5, and 6 had follow-up angiography that showed no evidence of restenosis. There are few good options to treated accelerated transplant vasculopathy. Radiation therapy may be a viable option in this difficult patient population.

Abciximab↗
PubMed2003

Deferoxamine enhances neovascularization and recovery of ischemic skeletal muscle in an experimental sheep model.

BACKGROUND: Iron chelators have been reported to interfere with inflammatory cells and possibly enhance vascular growth factor expression. The objective of this study was to investigate the efficacy of the iron chelator deferoxamine mesylate in preventing skeletal muscle ischemia. METHODS: The latissimus dorsi muscle (LDM) was mobilized in 20 adult sheep. Two separate pockets were created in each sheep. Autologous fibrin sealant with or without 100 mg/mL of deferoxamine mesylate (10 pockets) was added to the pockets. Deferoxamine mesylate alone was also applied to another 10 pockets, whereas the 10 other pockets served as controls. RESULTS: Conventional, indirect immunofluorescent enface staining showed that in nonmobilized, nonischemic LDM the capillary density was 196 +/- 14 capillaries/mm2 in the distal and 207 +/- 19 capillaries/mm2 in the middle part. After severe ischemic shock (subtotal mobilization), the muscle did not recover completely even after 2 months (149 +/- 15 capillaries/mm2 in the distal part and 177 +/- 16 capillaries/mm2 in the middle part of the LDM). Fibrin application only increased muscle neovascularization. The number of capillaries per mm2 of muscle increased to 250 +/- 25 in the distal part and to 271 +/- 24 in the middle part of the LDM. However, when fibrin was applied with added deferoxamine mesylate, the capillary density increased to 361 +/- 25 capillaries/mm2 in the distal part (p < 0.05 vs fibrin only; controls) and to 401 +/- 20 capillaries/mm2 in the middle part of the LDM (p < 0.05 vs fibrin only and p < 0.001 vs controls). The data are concordant with the blood flow estimation before and after mobilization (severe ischemic shock) in the different parts of the LDM. CONCLUSIONS: Local application of deferoxamine mesylate enhances neovascularization and recovery of surgically induced skeletal muscle ischemia in a sheep model.

Animals↗
PubMed2003

Transplantation of autologous endothelial cells induces angiogenesis.

This study examined the feasibility and efficacy of autologous endothelial cell (EC) transplantation using a fibrin matrix in the ischemic myocardium of sheep. Four weeks after placing an ameroid constrictor in the circumflex artery of 12 adult sheep, four animals (EC group) were subjected to EC transplantation. In four others (saline [SAL] group) saline with added inactivated cells was injected and four animals served as controls. Eight weeks after treatment the animals were sacrificed to assess histology and ultrastructure. Eight weeks after injection, ventricular function was markedly improved in the EC transplant group, but had deteriorated in the SAL and control groups. Myocardial blood flow was also increased in the EC group. Histology and electron microscopy revealed extensive neovascularization after EC transplantation and improved myocardial appearance. Heterotopic transplantation of EC within a fibrin matrix enhances neovascularization, increases myocardial blood flow, and improves left ventricular function.

Animals↗