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Biomedical subjects

George Dangas

Publications and source records attributed to George Dangas.

At least 55 records · Page 3Linked to original sources
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

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

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

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↗