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George Dangas

Publications and source records attributed to George Dangas.

At least 37 records · Page 2Linked to original sources
PubMed2005

Low hematocrit predicts contrast-induced nephropathy after percutaneous coronary interventions.

BACKGROUND: The relationship between low hematocrit and contrast-induced nephropathy has not been investigated. METHODS: Of 6,773 consecutive patients treated with percutaneous coronary intervention, contrast-induced nephropathy (an increase of >/=25% or >/=0.5 mg/dL in preprocedure serum creatinine, at 48 hours postprocedure) occurred in 942 (13.9%) patients. RESULTS: Rates of contrast-induced nephropathy steadily increased as baseline hematocrit quintile decreased (from 10.3% in the highest quintile to 23.3% in the lowest quintile) (chi(2) for trend, P < 0.0001). Stratification by baseline estimated glomerular filtration rate (eGFR) and baseline hematocrit showed that the rates of contrast-induced nephropathy were the highest (28.8%) in patients who had the lowest level for both baseline eGFR and hematocrit. Patients with the lowest eGFR but relatively high baseline hematocrit values had remarkably lower rates of contrast-induced nephropathy (15.8%, 12.3%, 17.1%, and 15.4% in 2nd, 3rd, 4th, and 5th quintiles of baseline hematocrit, respectively) (P < 0.0001). The rates of contrast-induced nephropathy increased with increment in change in hematocrit. Patients in the lowest quintile of baseline hematocrit with absolute hematocrit drop >5.9% had almost doubled rates of contrast-induced nephropathy compared with patients with hematocrit change <3.4% (38.1% vs. 18.8%, respectively) (P < 0.0001). By multivariate analysis, lower baseline hematocrit was an independent predictor of contrast-induced nephropathy; each 3% decrease in baseline hematocrit resulted in a significant increase in the odds of contrast-induced nephropathy in patients with and without chronic kidney disease (11% and 23%, respectively). When introduced into the multivariate model instead of baseline hematocrit, change in hematocrit also showed a significant association with contrast-induced nephropathy. CONCLUSION: Lower hematocrit is an important risk factor for contrast-induced nephropathy. Whether correcting the hematocrit prepercutaneous coronary intervention might decrease the rates of contrast-induced nephropathy should be addressed in a prospectively designed trial.

Adult↗
PubMed2005

Vascular closure devices: a review of their use after invasive procedures.

In the endovascular procedure setting, vascular closure devices (VCD) have emerged as an alternative to mechanical compression in order to achieve vascular hemostasis after puncture of the femoral artery. VCD are categorized based primarily on the principle mechanism of hemostasis, which includes biodegradable plug, suture, staples, or ultrasound. While VCD offer advantages over mechanical compression (shorter time to hemostasis and patient ambulation, high rate of patient satisfaction, and greater cost-effectiveness) complications related to the site of femoral access are still present. Efficacy and safety of VCD have been evaluated in a number of clinical trials, but to date there is still a lack of randomized clinical trials with sample sizes large enough to reveal superiority or non-inferiority of VCD compared with mechanical compression. Mechanical compression and VCD are effective and well tolerated in the setting of diagnostic procedures and procedures that do not use anticoagulation. For both methods, success rates are lower, and complication rates higher, in the setting of interventional procedures and when anticoagulation medications are used. Regardless of the device type, deployment failure is the major drawback of VCD. However, overall, meta-analysis data demonstrated that complications and success rates are not significantly different between mechanical compression and VCD. Current data suggest that the correct answer on whether or not to use VCD still remains in the operator domain where integration of clinical data and familiarity with a particular closure device plays a key role in achieving successful hemostasis and avoiding access site complication.

Case-Control Studies↗
PubMed2004

Predictors of and outcomes of early thrombosis following balloon angioplasty versus primary stenting in acute myocardial infarction and usefulness of abciximab (the CADILLAC trial).

We sought to identify the predictors and clinical outcomes of early thrombosis after primary angioplasty and stenting for acute myocardial infarction (AMI). Little is known about the correlates and prognosis of acute and subacute thromboses after percutaneous coronary intervention (PCI) for AMI. We therefore studied the frequency, clinical determinants, and implications of early thrombosis in a large trial of patients who had primary PCI. In the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications trial, 2,082 patients who had AMI were randomized in a 2 x 2 factorial design to primary stenting or to balloon angioplasty, each with and without abciximab. Early thrombosis occurred in 19 patients (0.9%) at a median of 2 days (range 0 to 23). Maximal balloon diameter was smaller, and aneurysmal and bifurcation lesions were more prevalent in the group with early thrombosis. Early thrombosis occurred in 0.4% of patients who had been randomized to receive abciximab versus 1.5% of control patients (p <0.01) and in 0.5% of patients who had been randomized to undergo stenting versus 1.4% of those who underwent balloon angioplasty (p = 0.04). By multivariate analysis, abciximab use was an independent predictor of no thrombosis (hazard ratio 0.27, 95% confidence interval 0.09 to 0.86, p = 0.026). Within 30 days, 5.3% of patients who had early thrombosis died, 32.9% developed reinfarction, and 89.5% required repeat target vessel revascularization (including bypass surgery in 11.1%). As a result, patients who had versus those who did not have early thrombosis had markedly higher rates of major adverse cardiac events at 30 days (94.7% vs 5.0%, p <0.0001) and at 1 year (94.7% vs 16.9%, p <0.0001). Patients who develop early thrombosis after primary PCI have a very high rate of major adverse cardiac events, including death and reinfarction, and usually require repeat coronary angioplasty or surgery for management. Complex baseline angiographic morphology and smaller maximal balloon diameter are predictors of early thrombosis after primary PCI for AMI. The incidence of early thrombosis after primary angioplasty and stenting is decreased by abciximab use.

Abciximab↗
PubMed2004

Impact of anemia on outcomes of patients undergoing percutaneous coronary interventions.

Of 6,929 consecutive patients who were treated with percutaneous coronary intervention, 1,708 (24.6%) had anemia according to criteria of the World Health Organization. Compared with patients who did not have anemia, those who did have anemia were older, more frequently women and African-American, had a smaller body mass index, and higher frequencies of cardiovascular risk factors and co-morbid conditions. Patients who had anemia compared with those who did not have anemia had significantly (p <0.0001) higher mortality rates during hospitalization (1.9% vs 0.4%) and at 1 year (12.8% vs 3.5%). After adjustment for potential confounders, baseline hematocrit remained a significant predictor of a 1-year mortality rate (hazard ratio 0.93 per 1% increase in hematocrit, 95% confidence interval 0.91 to 0.95).

Aged↗
PubMed2004

A simple risk score for prediction of contrast-induced nephropathy after percutaneous coronary intervention: development and initial validation.

OBJECTIVES: We sought to develop a simple risk score of contrast-induced nephropathy (CIN) after percutaneous coronary intervention (PCI). BACKGROUND: Although several risk factors for CIN have been identified, the cumulative risk rendered by their combination is unknown. METHODS: A total of 8,357 patients were randomly assigned to a development and a validation dataset. The baseline clinical and procedural characteristics of the 5,571 patients in the development dataset were considered as candidate univariate predictors of CIN (increase >or=25% and/or >or=0.5 mg/dl in serum creatinine at 48 h after PCI vs. baseline). Multivariate logistic regression was then used to identify independent predictors of CIN with a p value <0.0001. Based on the odds ratio, eight identified variables (hypotension, intra-aortic balloon pump, congestive heart failure, chronic kidney disease, diabetes, age >75 years, anemia, and volume of contrast) were assigned a weighted integer; the sum of the integers was a total risk score for each patient. RESULTS: The overall occurrence of CIN in the development set was 13.1% (range 7.5% to 57.3% for a low [ or=16] risk score, respectively); the rate of CIN increased exponentially with increasing risk score (Cochran Armitage chi-square, p < 0.0001). In the 2,786 patients of the validation dataset, the model demonstrated good discriminative power (c statistic = 0.67); the increasing risk score was again strongly associated with CIN (range 8.4% to 55.9% for a low and high risk score, respectively). CONCLUSIONS: The risk of CIN after PCI can be simply assessed using readily available information. This risk score can be used for both clinical and investigational purposes.

Aged↗
PubMed2004

Vascular complications associated with arteriotomy closure devices in patients undergoing percutaneous coronary procedures: a meta-analysis.

OBJECTIVES: This study was designed to assess the safety of arteriotomy closure devices (ACDs) versus mechanical compression by meta-analysis in patients undergoing percutaneous transfemoral coronary procedures. BACKGROUND: Although ACDs are widely applied for hemostasis after percutaneous endovascular procedures, their safety is controversial. METHODS: Randomized, case-control, and cohort studies comparing access-related complications using ACDs versus mechanical compression were analyzed. The primary end point was the cumulative incidence of vascular complications, including pseudoaneurysm, arteriovenous fistula, retroperitoneal hematoma, femoral artery thrombosis, surgical vascular repair, access site infection, and blood transfusion. RESULTS: A total of 30 studies involving 37,066 patients were identified. No difference in complication incidence between Angio-Seal and mechanical compression was revealed in the diagnostic (Dx) setting (odds ratio [OR] 1.08, 95% confidence interval [CI] 0.11 to 10.0) or percutaneous coronary interventions (PCI) (OR 0.86, 95% CI 0.65 to 1.12). Meta-analysis of randomized trials only showed a trend toward less complications using Angio-Seal in a PCI setting (OR 0.46, 95% CI 0.20 to 1.04; p = 0.062). No differences were observed regarding Perclose in either Dx (OR 1.51, 95% CI 0.24 to 9.47) or PCI (OR 1.21, 95% CI 0.94 to 1.54) setting. An increased risk in complication rates using VasoSeal in the PCI setting (OR 2.25, 95% CI 1.07 to 4.71) was found. The overall analysis favored mechanical compression over ACD (OR 1.34, 95% CI 1.01 to 1.79). CONCLUSIONS: In the setting of Dx angiography, the risk of access-site-related complications was similar for ACD compared with mechanical compression. In the setting of PCI, the rate of complications appeared higher with VasoSeal.

Angioplasty, Balloon, Coronary↗
PubMed2004

Role of the endothelium in modulating neointimal formation: vasculoprotective approaches to attenuate restenosis after percutaneous coronary interventions.

Restenosis at the site of an endoluminal procedure remains a significant problem in the practice of interventional cardiology. We present current data on intimal hyperplasia, which identify the major role of endothelial cells (ECs) in the development of restenosis. Considering endothelial denudation as one of the most important mechanisms contributing to restenosis, we focus more attention on methods of accelerating restoration of endothelial continuity. Prevention of restenosis may be achieved by promoting endothelial regeneration through the use of growth factors, EC seeding, vessel reconstruction with autologous EC/fibrin matrix, and the use of estrogen-loaded stents and stents designed to capture progenitor ECs.

Angioplasty, Balloon, Coronary↗
PubMed2004

Relation of final lumen dimensions in saphenous vein grafts after stent implantation to outcome.

Larger final lumen dimensions after percutaneous coronary interventions in native coronary arteries lead to lower restenosis rates. We sought to determine the impact of stent expansion, as assessed by intravascular ultrasound, on clinical results of stent implantation in saphenous vein grafts (SVGs). We identified 226 consecutive patients who underwent intravascular ultrasound-guided stenting of 234 de novo SVG lesions. Patients were divided into 2 groups based on the final stent cross-sectional area (CSA): group I (stent CSA <100% of the reference lumen CSA, n = 176 patients, 182 lesions) and group II (stent CSA >/=100% of the reference lumen CSA, n = 50 patients, 52 lesions). Baseline patient characteristics were similar between the 2 groups with the exception of smaller lesions in group II. More aggressive stent expansion (group II) was associated with (1) increased rates of in-hospital non-Q-wave myocardial infarction (29% vs 17%, p = 0.05), (2) any myocardial infarction (26% vs 8%, p = 0.003) at 1-year follow-up, and (3) no improvement in target vessel revascularization at 1 year (31% vs 26%, p = 0.3). Aggressive stent expansion in SVG lesions resulted in higher myocardial infarction rates and, unlike native arteries, no improvement in target vessel revascularization rate at 1 year. A less aggressive stent implantation strategy in SVGs than in native coronary lesions appears prudent.

Aged↗
PubMed2004

Comparison of differences in outcome after percutaneous coronary intervention in men versus women <40 years of age.

We evaluated the outcomes of 177 consecutive patients (43 women, 134 men) <40 years of age with premature atherosclerosis who underwent percutaneous coronary intervention. Women were younger, had more diabetes mellitus (37% vs 10%; p <0.001), but less hyperlipidemia (58% vs 75%; p <0.001) compared with men. In-hospital vascular complications and 1-year mortality rate or Q-wave myocardial infarction (7.9% vs 0.08%, p <0.01) were higher in women. By multivariable regression analysis, female gender was the only independent predictor of vascular complications (odds ratio, 14.1; 95% confidence intervals, 1.59 to 125, p = 0.01) and of 1-year mortality rate or nonfatal myocardial infarction (odds ratio, 12.5; 95% confidence interval, 1.14 to 111, p = 0.03). Women with premature coronary disease had a distinctive risk factor profile relative to men, with a predominance of diabetes and hypercholesterolemia, and were at higher risk of developing vascular and ischemic complications after percutaneous coronary intervention, warranting aggressive risk factor modification and vigilance in this population.

Adult↗
PubMed2004

Contribution of stent underexpansion to recurrence after sirolimus-eluting stent implantation for in-stent restenosis.

BACKGROUND: We used intravascular ultrasound (IVUS) to evaluate recurrence after sirolimus-eluting stent (SES) implantation treatment of in-stent restenosis (ISR). METHODS AND RESULTS: Forty-eight ISR lesions (41 patients with objective evidence of ischemia) were treated with SES. Recurrent ISR was identified in 11 lesions (all focal); repeat revascularization was performed in 10. These were compared with 16 patients (19 lesions) without recurrence as documented by angiography. Nine of 11 recurrent lesions had a minimum stent area (MSA) <5.0 mm2 versus 5 of 19 nonrecurrent lesions (P=0.003); 7 of 11 recurrent lesions had an MSA <4.0 mm2 versus 4 of 19 nonrecurrent lesions (P=0.02); and 4 of 11 recurrent lesions had an MSA <3.0 mm2 versus 1 of 19 nonrecurrent lesions (P=0.03). A gap between SESs was identified in 3 of 11 recurrences versus 1 of 19 nonrecurrent lesions. CONCLUSIONS: Stent underexpansion is a significant cause of failure after SES implantation treatment of ISR.

Combined Modality Therapy↗
PubMed2004

Comparison of frequency of hemorrhagic stroke in patients <75 years versus > or =75 years of age among patients receiving glycoprotein IIb/IIIa inhibitors during percutaneous coronary interventions.

We identified 1,369 consecutive patients who received glycoprotein IIb/IIIa inhibitors during 1,461 stenting procedures (2,382 lesions); of these, 240 (17.5%) were aged > or =75 years (253 procedures, 430 lesions). Very elderly patients (> or =75 years) had similar in-hospital outcomes but a higher hemorrhagic stroke rate than patients aged <75 years.

Age Factors↗
PubMed2004

Gamma radiation for in-stent restenosis: effect of lesion length on angiographic and clinical outcomes.

The relation between lesion length and effectiveness of gamma radiation treatment (gamma-RT) has not been well described. We evaluated the acute and long-term outcome according to baseline lesion length in 130 patients treated with (192)Ir in the Washington Radiation for In-Stent Restenosis Trial; 44 (35.5%) had baseline short in-stent restenosis (ISR) lesions (length < 15 mm) and 80 (64.5%) long ISR lesions (length > or = 15 mm). At 6-month follow-up after gamma-RT, the short ISR group had larger lumen dimensions and lower late loss than the long ISR group. Restenosis rate was significantly higher in patients with long ISR for both the placebo (74% vs. 39%; P = 0.01) and the gamma-RT arm (31% vs. 5.3%; P = 0.04). gamma-RT significantly improved the angiographic outcome in the short-lesion groups but had the more pronounced effect on the reduction of clinical events after treatment of long ISR group. Lesion length remains a powerful predictor of recurrent ISR and clinical events after treatment of ISR even with gamma-RT.

Brachytherapy↗
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

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

Acute Catheterization and Urgent Intervention Triage strategY (ACUITY) trial: study design and rationale.

BACKGROUND: Patients with acute coronary syndromes (ACS; unstable angina and non-ST-segment elevation myocardial infarction) are at significant risk for death and myocardial infarction. Early angiography followed by revascularization is considered the treatment of choice for moderate- to high-risk patients with ACS. However, despite the integration of newer therapies including stents, glycoprotein IIb/IIIa inhibitors, and thienopyridines, the rate of adverse ischemic events still remains unacceptably high, and the intensive pharmacologic regimens used to stabilize the disrupted atherosclerotic plaque and support angioplasty and surgical revascularization procedures elicit a high rate of bleeding complications. Pilot trials suggest that the thrombin-specific anticoagulant bivalirudin may improve clinical outcomes in ACS. STUDY DESIGN: In the Acute Catheterization and Urgent Intervention Triage strategY (ACUITY) trial, 13,800 patients with moderate- to high-risk ACS are being prospectively randomly assigned at up to 600 centers to unfractionated heparin or enoxaparin + IIb/IIIa inhibition, versus bivalirudin + IIb/IIIa inhibition, versus bivalirudin + provisional IIb/IIIa inhibition. All patients undergo cardiac catheterization within 72 hours, followed by percutaneous or surgical revascularization when appropriate. In a second random assignment, patients assigned to receive IIb/IIIa inhibitors are subrandomized to upstream drug initiation, versus IIb/IIIa inhibitor administration during angioplasty only. The primary study end point is the composite of death, myocardial infarction, unplanned revascularization for ischemia, and major bleeding at 30 days. Clinical follow-up will continue for 1 year. CONCLUSIONS: The ACUITY trial is the largest study yet performed in patients with ACS undergoing an invasive strategy. In addition to evaluating the utility of bivalirudin in ACS, this study will also provide important guidance regarding the necessity for and timing of IIb/IIIa inhibitor administration.

Angina, Unstable↗
PubMed2004

Comparison of safety and efficacy between first and second generation of angio-seal closure devices in interventional patients.

Arterial closure devices are safe and effective in selected patients, with complication rates similar to or lower than manual compression. The purpose of this study was to compare the safety and efficacy of the first- and new-generation Angio-Seal devices in patients undergoing PCI. This study found that the new Angio-Seal STS Platform device can secure hemostasis after PCI in a safe and effective manner similar to the old device. The new platform is easier for the operator and for the patients.

Adult↗