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Martin B Leon

Publications and source records attributed to Martin B Leon.

At least 145 records · Page 8Linked to original sources
PubMed2003

Impact of gender on the incidence and outcome of contrast-induced nephropathy after percutaneous coronary intervention.

BACKGROUND: Contrast-induced nephropathy (CIN) is a recognized complication after percutaneous interventions (PCI). We sought to determine the impact of gender on incidence and clinical outcome of CIN. METHODS AND RESULTS: Of a total 8,628 patients who underwent PCI, there were 1,431 (16.5%) who developed CIN (defined as > 25% rise in creatinine after PCI). Patients were followed clinically for one year. CIN was present in 23.6% of female versus 17.4% of male patients (p < 0.0001). Multivariate analysis showed that female gender (OR = 1.4, 95% CI = 1.25 1.60; p < 0.0001), pre-PCI chronic renal failure (CRF) (OR= 1.8, 95% CI = 1.53 2.10, p < 0.0001), diabetes mellitus (OR = 1.5, 95% CI = 1.34 1.70; p < 0.0001), age (OR = 1.01, 95% CI = 1.01 1.02, p < 0.0001), and hypertension (OR = 1.2, 95% CI = 1.06 1.36, p = 0.0035) were independent predictors of CIN. Clinical outcomes after CIN were examined in patients with or without CRF. Among patients without CRF who developed CIN, females (n = 465) had higher rates of one-year mortality, and MACE comparing to males (n = 710) without CRF (14% vs. 10% mortality, 36% vs. 30% MACE; p = 0.05 and 0.06, respectively). In patients with CRF who developed CIN, we found no significant gender differences in one-year clinical events (37% vs. 36% mortality, 42% vs. 45% MACE; p = 0.8 and 0.6, respectively). By multivariate analysis only baseline CRF, diabetes, age, functional NYHA IV class were identified as independent predictors of one-year mortality in patients with CIN after PCI. CONCLUSIONS: Female gender is an independent predictor of CIN development after PCI and a marker of worse 1-year mortality after CIN in patients without baseline CRF. After CIN is developed, pre-PCI CRF, diabetes mellitus, age, severe heart failure (not gender) are independent predictors of one-year mortality.

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PubMed2003

Benefits of cutting balloon before stenting.

UNLABELLED: The objectives of this study were to prospectively evaluate the safety and feasibility of pretreating the culprit coronary artery lesion with cutting balloon (CB) angioplasty prior to coronary stent implantation. BACKGROUND: The CB has shown promise for the treatment of de novo coronary lesions and in-stent restenoses, but has not been prospectively evaluated for use prior to stent implantation. METHODS: Patients with significant coronary artery disease requiring stent placement had the culprit lesion pretreated with a CB. Stents were deployed to cover the entire segment pretreated with the CB. Intravascular ultrasound (IVUS) was used to interrogate acute luminal gain following stent implantation and after serial post-deployment inflation pressures ranging from 8 16 atmospheres (atm). Coronary angiograms were also obtained to determine luminal diameter. In-hospital complication rates were noted. RESULTS: Fifty-one patients were treated with the CB prior to stent implantation. Minimal stent cross-sectional area increased significantly with increasing inflation pressures between 8 and 10 atm (p < 0.0004) and between 10 and 12 atm (p = 0.0049). The minimal stent cross-sectional area achieved, as measured by IVUS, was 7.59 mm2 2.00 mm2 at 8 atm, 8.06 mm2 1.53 mm2 at 10 atm and 8.72 mm2 1.58 mm2 at 12 atm. The final in-stent percent diameter stenosis was lower compared to pre-procedure (5.4% 12.2% versus 64.1% 14.1%, respectively) by quantitative coronary angiography. CONCLUSION: The CB can be used prior to stent implantation to attain significant gains in minimal stent cross-sectional areas at relatively low pressures.

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PubMed2002

Percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis: first human case description.

BACKGROUND: The design of a percutaneous implantable prosthetic heart valve has become an important area for investigation. A percutaneously implanted heart valve (PHV) composed of 3 bovine pericardial leaflets mounted within a balloon-expandable stent was developed. After ex vivo testing and animal implantation studies, the first human implantation was performed in a 57-year-old man with calcific aortic stenosis, cardiogenic shock, subacute leg ischemia, and other associated noncardiac diseases. Valve replacement had been declined for this patient, and balloon valvuloplasty had been performed with nonsustained results. METHODS AND RESULTS: With the use of an antegrade transseptal approach, the PHV was successfully implanted within the diseased native aortic valve, with accurate and stable PHV positioning, no impairment of the coronary artery blood flow or of the mitral valve function, and a mild paravalvular aortic regurgitation. Immediately and at 48 hours after implantation, valve function was excellent, resulting in marked hemodynamic improvement. Over a follow-up period of 4 months, the valvular function remained satisfactory as assessed by sequential transesophageal echocardiography, and there was no recurrence of heart failure. However, severe noncardiac complications occurred, including a progressive worsening of the leg ischemia, leading to leg amputation with lack of healing, infection, and death 17 weeks after PHV implantation. CONCLUSIONS: Nonsurgical implantation of a prosthetic heart valve can be successfully achieved with immediate and midterm hemodynamic and clinical improvement. After further device modifications, additional durability tests, and confirmatory clinical implantations, PHV might become an important therapeutic alternative for the treatment of selected patients with nonsurgical aortic stenosis.

Amputation, Surgical↗
PubMed2002

Long-term outcome of patients treated with repeat percutaneous coronary intervention after failure of gamma-brachytherapy for the treatment of in-stent restenosis.

BACKGROUND: Although (192)Ir intracoronary brachytherapy has been demonstrated to dramatically reduce the recurrence of in-stent restenosis, up to 24% of these patients will still require repeat target-vessel revascularization. The short- and long-term outcomes of repeat percutaneous intervention in this population have not been characterized. METHODS AND RESULTS: Analysis was performed of all patients enrolled in the GAMMA-I and GAMMA-II brachytherapy trials who underwent repeat percutaneous target lesion revascularization (TLR) because of restenosis. Subjects were divided into 2 cohorts: those who had received (192)Ir brachytherapy and those randomized to placebo. Forty-five (17.6%) of a total of 256 patients whose index treatment was intracoronary radiation therapy and 36 (29.8%) of 121 patients whose index treatment was placebo required repeat percutaneous TLR. The mean time to this first TLR was 295+/-206 days in the irradiated group and 202+/-167 days in the placebo group (P=0.03). Acute procedural success occurred in 100% of irradiated patients and 94% of placebo controls (P=0.19). After the first TLR, a subsequent TLR was required in 15 (33.3%) of 45 brachytherapy patients versus 17 (47.2%) of 36 placebo failure patients (P=0.26). There was no significant difference in time to second TLR between the 2 groups. Other long-term major adverse event rates in both groups were comparable to those of other contemporary angioplasty/stenting series. CONCLUSIONS: In those patients who "fail" (192)Ir intracoronary brachytherapy for in-stent restenosis, treatment with (192)Ir delays the time to first TLR. Additionally, repeat percutaneous intervention in these patients is safe and efficacious in the short term, with acceptable long-term results.

Angioplasty, Balloon, Coronary↗
PubMed2002

Cost-effectiveness of gamma radiation for treatment of in-stent restenosis: results from the Gamma-1 trial.

BACKGROUND: Recently, several randomized trials have demonstrated that intracoronary brachytherapy can reduce the rates of both angiographic and clinical restenosis in patients undergoing percutaneous coronary intervention (PCI) for in-stent restenosis. Whether this practice is cost-effective is unknown. METHODS AND RESULTS: Between December 1997 and July 1998, 252 patients with in-stent restenosis were randomized to receive brachytherapy or placebo after successful PCI as part of the Gamma-1 trial. We collected detailed resource utilization and cost data for each patient's initial hospitalization and for 1 year after randomization. Compared with conventional treatment, intracoronary brachytherapy increased procedure duration, physician services, and equipment costs. As a result, initial costs were increased by nearly $4100 per patient ($15 724 versus $11 675, P<0.001). Over the 1-year follow-up period, brachytherapy reduced the need for repeat revascularization by 21% and reduced the need for bypass surgery by 44%. Although follow-up medical care costs were $2200/patient lower with brachytherapy, total costs remained higher at 1 year ($28 543 versus $26 737, P=0.46). In a sensitivity analysis that incorporated recent technical modifications and the use of prolonged antiplatelet therapy to prevent late thrombotic occlusion, follow-up cost savings increased to $3600/patient, and 1-year costs were slightly lower with brachytherapy ($26 352 versus $26 729, P=0.87). Subgroup analysis demonstrated significant cost savings in patients with diabetes and patients who did not undergo repeat stenting. CONCLUSIONS: As performed in the Gamma-1 trial, coronary brachytherapy for in-stent restenosis improved clinical outcomes but increased 1-year costs compared with standard therapy. If late thrombosis can be eliminated, however, this technology has the potential to reduce overall medical care costs.

Angioplasty, Balloon, Coronary↗
PubMed2002

Effect of catheter-based iridium-192 gamma brachytherapy on the added risk of restenosis from diabetes mellitus after intervention for in-stent restenosis (subanalysis of the GAMMA I Randomized Trial).

Catheter-based intracoronary radiation therapy using iridium-192 (Ir-192) has been shown to be effective in reducing recurrent coronary restenosis after initial percutaneous treatment of in-stent restenosis. Patients with diabetes mellitus (DM) have a higher risk of recurrent restenosis than nondiabetics for nonstented and in-stent restenosis coronary lesions. The use of Ir-192 for preventing recurrent restenosis in such patients remains undefined. The GAMMA I trial was a prospective, randomized, double-blind, multicenter trial of 252 patients with in-stent restenosis who underwent percutaneous coronary intervention and were assigned to receive either Ir-192 (131 patients) or catheter-based placebo (121 patients). DM was present in 79 patients (31%) (41 patients received Ir-192 and 38 patients received placebo) and was absent in 173 patients (90 patients received Ir-192 and 83 patients received placebo). At 6-month follow-up in the GAMMA I trial, the angiographic in-lesion binary restenosis rate was lower in the Ir-192 arm than in the placebo arm (32.4 vs 55.3, p = 0.01). When patients were stratified by the presence of DM, the antirestenosis effect of Ir-192 was larger for diabetic patients than for nondiabetic patients (absolute in-lesion restenosis rate was reduced by 40% for diabetics and 16% for nondiabetics). Thus, adjunctive Ir-192 intracoronary radiation therapy reduces recurrent restenosis after intervention for in-stent restenosis in patients with and without DM. The relative impact of this treatment is more pronounced in diabetic patients because it appears to neutralize the added risk of recurrent restenosis seen in proliferative diabetic lesions.

Brachytherapy↗
PubMed2002

Five-year clinical follow-up after intracoronary radiation: results of a randomized clinical trial.

BACKGROUND: Several clinical trials indicate that intracoronary radiation is safe and effective for treatment of restenotic coronary arteries. We previously reported 6-month and 3-year clinical and angiographic follow-up demonstrating significant decreases in target lesion revascularization (TLR) and angiographic restenosis after gamma radiation of restenotic lesions. The objective of this study was to document the clinical outcome 5 years after treatment of restenotic coronary arteries with catheter-based iridium-192 (192Ir). METHODS AND RESULTS: A double-blind, randomized trail compared 192Ir to placebo sources in patients with restenosis after coronary angioplasty. Over a 9-month period, 55 patients were enrolled; 26 were randomized to 192Ir and 29 to placebo. At 5-year follow-up, TLR was significantly lower in the 192Ir group (23.1% versus 48.3%; P=0.05). There were 2 TLRs between years 3 and 5 in patients in the 192Ir group and none in patients in the placebo group. The 5-year event-free survival rate (freedom from death, myocardial infarction, or TLR) was greater in 192Ir-treated patients (61.5% versus 34.5%; P=0.02). CONCLUSIONS: Despite apparent mitigation of efficacy over time, there remains a significant reduction in TLR at 5 years and an improvement in event-free survival in patients treated with intracoronary 192Ir. The early clinical benefits after intracoronary gamma radiation with 192Ir seem durable at 5-year clinical follow-up.

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PubMed2002

Comparison of clinical outcomes using stents versus no stents after percutaneous coronary intervention for proximal left anterior descending versus proximal right and left circumflex coronary arteries.

Previous studies have demonstrated that proximal left anterior descending (LAD) stenoses have higher rates of restenosis after angioplasty than stenoses in other coronary segments. Stenting strategies may reduce this high rate of LAD restenosis. The study population included 1,289 patients with proximal coronary artery stenoses treated with percutaneous coronary interventions (PCI) with or without stents for single-vessel coronary disease between 1994 and 1999. Patients were divided into 4 groups: non-stent PCI in the proximal LAD artery (n = 168), non-stent PCI in proximal right/circumflex artery (n = 217), stent in the proximal LAD artery (n = 364), and stent to proximal right/circumflex artery (n = 540). Procedural success was higher in the stenting groups, but there were no significant differences in the major in-hospital events between the different lesion locations among the groups. At 1-year follow-up, there was no difference in mortality or myocardial infarction between the groups. There was no significant difference in the rate of target lesion revascularization (TLR) in the patients with proximal LAD stents compared with the patients with proximal right/circumflex coronary artery stents (10.1% vs 13.8%, p = 0.11). In the patients who did not receive stents with proximal narrowings, there was a significant increase in TLR in the LAD group compared with the right/circumflex group (21.1% vs 12.5%, p = 0.04). Thus, patients with proximal stenoses treated with non-stenting strategies have lower procedural success than those treated with stenting strategies; the patients with proximal LAD non-stent PCI have significantly higher rates of clinical restenosis than patients with proximal right and circumflex stenoses. A stenting strategy for proximal LAD stenoses appears to attenuate the differences of clinical restenosis noted after non-stent PCI.

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PubMed2002

Intramural coronary delivery of advanced antisense oligonucleotides reduces neointimal formation in the porcine stent restenosis model.

OBJECTIVES: We evaluated the long-term influence of intramural delivery of advanced c-myc neutrally charged antisense oligonucleotides (Resten-NG) on neointimal hyperplasia after stenting in a pig model. BACKGROUND: Neointimal hyperplasia after percutaneous coronary interventions is one of the key components of the restenotic process. The c-myc is a critical cell division cycle protein involved in the formation of neointima. METHODS: In short-term experiments, different doses (from 500 microg to 5 mg) of Resten-NG or saline were delivered to the stent implantation site with an infiltrator delivery system (Interventional Technologies, San Diego, California). Animals were euthanized at 2, 6 and 18 h after interventions, and excised vessels were analyzed for c-myc expression by Western blot. In long-term experiments, either saline or a dose of 1, 5 or 10 mg of Resten-NG was delivered in the same fashion, and animals were euthanized at 28 days after the intervention. RESULTS: Western blot analysis demonstrated inhibition of c-myc expression and was dose dependent. Morphometry showed that the intimal area was 3.88 +/- 1.04 mm(2) in the control. There was statistically significant reduction of intimal areas in the 5 and 10 mg groups (2.01 +/- 0.66 and 1.95 +/- 0.91, respectively, p < 0.001) but no significant reduction in the 1 mg group (2.81 +/- 0.56, p > 0.5) in comparison with control. CONCLUSIONS: This study demonstrated that intramural delivery of advanced c-myc neutrally charged antisense morpholino compound completely inhibits c-myc expression and dramatically reduces neointimal formation in a dose dependent fashion in a porcine coronary stent restenosis model, while allowing for complete vascular healing.

Angioplasty, Balloon, Coronary↗
PubMed2002

Randomized trial of a distal embolic protection device during percutaneous intervention of saphenous vein aorto-coronary bypass grafts.

BACKGROUND: Stents provide effective treatment for stenotic saphenous venous aorto-coronary bypass grafts, but their placement carries a 20% incidence of procedure-related complications, which potentially are related to the distal embolization of atherosclerotic debris. We report the first multicenter randomized trial to evaluate use of a distal embolic protection device during stenting of such lesions. METHODS AND RESULTS: Of 801 eligible patients, 406 were randomly assigned to stent placement over the shaft of the distal protection device, and 395 were assigned to stent placement over a conventional 0.014-inch angioplasty guidewire (control group). The primary end point-a composite of death, myocardial infarction, emergency bypass, or target lesion revascularization by 30 days-was observed in 65 patients (16.5%) assigned to the control group and 39 patients (9.6%) assigned to the embolic protection device (P=0.004). This 42% relative reduction in major adverse cardiac events was driven by myocardial infarction (8.6% versus 14.7%, P=0.008) and "no-reflow" phenomenon (3% versus 9%, P=0.02). Clinical benefit was seen even when platelet glycoprotein IIb/IIIa receptor blockers were administered (61% of patients), with composite end points occurring in 10.7% of protection device patients versus 19.4% of control patients (P=0.008). CONCLUSIONS: Use of this distal protection device during stenting of stenotic venous grafts was associated with a highly significant reduction in major adverse events compared with stenting over a conventional angioplasty guidewire. This demonstrates the importance of distal embolization in causing major adverse cardiac events and the value of embolic protection devices in preventing such complications.

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PubMed2002

Quantitative coronary angiography in regression trials: a review of methodologic considerations, endpoint selection, and limitations.

Several quantitative angiographic methods (visual assessment, digital hand-held calipers, and automated edge detection) have been successfully used to assess coronary atherosclerosis regression. These methods are applicable for (1) continuous measures of disease progression and regression, including patient-based, segment-based, and lesion-based analyses; and (2) categorical assessment of disease progression and regression (the use of a predefined threshold to categorize the course of disease). Angiographic methods and criteria for assessing disease progression each have distinct advantages and disadvantages, which accounts for the methodologic diversity seen in clinical trials.

Coronary Angiography↗
PubMed2002

Impact of normalized myocardial perfusion after successful angioplasty in acute myocardial infarction.

OBJECTIVES: We sought to evaluate and validate the ability of the angiographic myocardial blush grade to risk stratify patients after successful angioplasty in acute myocardial infarction (AMI). BACKGROUND: Although epicardial Thrombolysis In Myocardial Infarction (TIMI)-3 flow is restored in >90% of patients undergoing primary percutaneous coronary intervention (PCI), normal myocardial perfusion may be present less frequently and may detrimentally impact survival. METHODS: A cohort of 173 consecutive patients undergoing intervention within 24 h of AMI onset were studied. High-risk features of this population included failed thrombolysis in 39%, cardiogenic shock in 17% and saphenous vein graft culprit in 11% of patients. RESULTS: Despite the restoration of TIMI-3 flow in 163 (94.2%) patients, myocardial perfusion, as evidenced by normal contrast opacification of the myocardial bed subtended by the infarct artery (myocardial blush), was normal in only 29.4% of patients with TIMI-3 flow following PCI, and in no patient with TIMI 0 to 2 flow. In patients in whom TIMI-3 flow was restored, survival was strongly dependent on the myocardial perfusion grade; one-year cumulative mortality was 6.8% with normal myocardial blush, 13.2% with reduced myocardial blush and 18.3% in patients with absent myocardial blush (p = 0.004). CONCLUSIONS: Abnormal myocardial perfusion is present in most patients following primary or rescue PCI in AMI, despite restoration of brisk epicardial coronary flow. In high risk patients achieving TIMI-3 flow after intervention, the myocardial blush score may be used to stratify prognosis into excellent, intermediate and poor survival. Further study is warranted to examine whether adjunctive mechanical or pharmacologic strategies can further improve myocardial perfusion and survival of patients with acute myocardial infarction undergoing intervention.

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PubMed2002

Quantitative angiographic methods for appropriate end-point analysis, edge-effect evaluation, and prediction of recurrent restenosis after coronary brachytherapy with gamma irradiation.

OBJECTIVES: The study was done to investigate the relationship between clinical restenosis and the relative angiographic location of the recurrent restenotic lesion, after treatment of in-stent restenosis with vascular brachytherapy in the Washington Radiation for In-Stent Restenosis Trial (WRIST). BACKGROUND: Intracoronary radiation therapy reduces recurrence of in-stent restenosis. We investigated the above objective in patients enrolled in WRIST. METHODS: The WRIST study randomized 130 patients to double-blinded therapy with gamma irradiation (iridium-192 [(192)Ir]) versus placebo after interventional treatment of diffuse in-stent restenosis. After the intervention and at follow-up, three vessel segments were individually analyzed with quantitative coronary angiography: 1) the "stent," 2) the "radiation ribbon," and 3) the "ribbon+margin" segment (including 5 mm on either end of the injured or radiation-ribbon segment). Receiver operator curves (ROC) were used to assess the value of the follow-up percent diameter stenosis (DS) for each of the three analyzed segments in predicting target vessel revascularization (TVR). RESULTS: (192)Ir reduced recurrent restenosis (23.7% vs. 60.7%, p < 0.001) and the length of recurrent restenosis (8.99 +/- 4.34 mm vs. 17.54 +/- 10.48 mm, p < 0.001) at follow-up compared to placebo. Isolated stent edge (3.4%) and ribbon edge (1.7%) restenoses were infrequent in both groups. The best angiographic surrogate of TVR was the 50% follow-up DS obtained from the ribbon+margin analysis (ROC area 0.806). CONCLUSIONS: In WRIST, not only was (192)Ir therapy effective in reducing restenosis, but it also reduced the lesion length of treatment failures by 50%, and it was not associated with edge proliferation. The restenosis rate obtained from the vessel segment inclusive of the dose fall-off zones was the best correlate of TVR and should become a standard analysis site in all vascular brachytherapy trials.

Brachytherapy↗
PubMed2002

Clinical outcome following percutaneous coronary interventions in patients with chronic renal failure.

The clinical outcome of patients with chronic renal failure (CRF) who undergo percutaneous coronary intervention (PCI) has not been systematically evaluated in a large cohort of patients. We retrospectively analyzed the in-hospital and 1-year clinical outcomes of 10,076 consecutive patients who underwent PCI between January 1994 and December 1997. A total of 95 patients (0.9%) had end-stage renal disease (ESRD) on dialysis, 786 patients (7.8%) had CRF, and 9,125 patients (90.6%) had normal renal function. Despite an angiographic success rate of 97% in all three groups, in-hospital mortality was significantly higher among patients with renal disease, whether they were on dialysis or not, when compared to patients without renal dysfunction (6.8% vs. 4.2% vs. 0.9%; P < 0.0001). At 1-year follow-up, mortality rate was 48.8% for ESRD, 25.7% for patients with CRF, and 5.5%, for patients without renal dysfunction (P < 0.0001). By multivariate analysis, high left ventricular ejection fraction and creatinine clearance were associated with decreased late mortality (OR = 0.84 and 0.95; P < 0.0001), whereas ESRD (OR = 3.65; P = 0.0002), non-Q-wave myocardial infarction (OR = 2.21; P < 0.0001), diabetes mellitus (OR = 1.99; P < 0.0001), and CRF (OR = 1.74; P = 0.003) were independent correlates of increased late mortality. Therefore, PCI in patients with impaired renal function, whether on dialysis or not, is associated with poor in-hospital and 1-year survival.

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