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George Dangas

Publications and source records attributed to George Dangas.

At least 19 recordsLinked to original sources
PubMed2006

Outcome after acute incomplete sirolimus-eluting stent apposition as assessed by serial intravascular ultrasound.

We investigated the fate of postprocedural incomplete stent apposition (ISA) after sirolimus-eluting stent (SES) implantation by evaluating long-term intravascular ultrasound findings in 168 consecutive patients (182 de novo lesions). Postprocedural ISA was defined as > or = 1 stent strut that was clearly separated from the vessel wall with evidence of blood speckle behind the strut without overlapping a side branch. After SES implantation, there were 61 ISA sites in 46 stents in 31 patients (23 at the proximal edge, 7 at the distal edge, and 31 within the stent body). There were no clinical, procedural, or intravascular ultrasound measurement differences between patients and lesions with versus without ISA. At follow-up, 15 acute ISA sites (25%) in 11 patients completely resolved and 40 sites (75%) in 20 patients persisted, although 32 of 46 persisting ISA sites (70%) decreased. There was a greater decrease in effective lumen area and a greater increase in peristent plaque area in the complete-resolution group than in the persistent-ISA group. No lesion developed stent thrombosis or in-stent restenosis (angiographic diameter stenosis > 50%). Six acute ISA sites were also associated with new, late acquired ISA, only 1 of which resulted in aneurysm formation. Although most ISAs after SES implantation do not resolve completely, the incidence of restenosis or thrombosis is not affected.

Acute Disease↗
PubMed2006

Drug-eluting stents in the treatment of intermediate lesions: pooled analysis from four randomized trials.

OBJECTIVES: To address the safety and efficacy of drug-eluting stents (DES) in the treatment of intermediate lesions, we performed a pooled analysis of four randomized DES versus bare-metal stent (BMS) trials and assessed outcomes among patients with intermediate lesions. BACKGROUND: Before the introduction of DES, intermediate coronary lesions were commonly managed based on physiologic or anatomic assessment of lesion severity. The DES may challenge this paradigm. METHODS: The study population involved 167 of 2,478 randomized patients (6.7%) with intermediate lesions (diameter stenosis <50% [mean 44%] by quantitative coronary angiography) from the Sirolimus-coated Bx Velocity Balloon Expandable Stent in the Treatment of Patients with De Novo Coronary Artery Lesions (SIRIUS), TAXUS-IV, and the First and Second First Use to Underscore Restenosis Reduction with Everolimus (FUTURE-I and -II) trials. End points examined included early (in-hospital and 30-day) and late (1-year) major adverse cardiac events (MACE), including cardiac death, myocardial infarction (MI), target vessel revascularization (TVR), stent thrombosis, and follow-up angiographic restenosis. RESULTS: Patients with intermediate lesions randomized to DES versus BMS had low rates of 30-day MACE (1.1% vs. 4.0% respectively; p = 0.22). At one-year follow-up, patients treated with DES versus BMS had similar rates of cardiac death (0% vs. 2.7%, respectively; p = 0.11) and MI (3.4% vs. 5.4%; p = 0.49) but markedly lower rates of TVR (3.4% vs. 20.3%; p = 0.0004), MACE (5.6% vs. 25.4%; p = 0.0003), and binary angiographic restenosis (1.8% vs. 34.0%; p < 0.0001). No patient in either group developed stent thrombosis. CONCLUSIONS: Compared with BMS, treatment of intermediate lesions with DES appears safe and results in a marked reduction in clinical and angiographic restenosis. The efficacy of DES may require a reevaluation of current treatment paradigms for intermediate lesions.

Coronary Restenosis↗
PubMed2006

Intravascular ultrasound assessment of fibrous cap remnants after coronary plaque rupture.

BACKGROUND: Although intravascular ultrasound (IVUS) can detect plaque rupture, the fibrous cap remnant has not previously been studied in detail. The aim of the present study is to assess the fibrous cap remnants by IVUS in ruptured plaques. METHODS: In 53 patients, a ruptured plaque with a fibrous cap remnant was studied by IVUS. RESULTS: In 36 (68%) patients, the rupture of the fibrous cap appeared to have occurred at the shoulder. The absolute length of the fibrous cap remnant was significantly longer in the center rupture site compared with the shoulder rupture site (1.37 +/- 0.56 vs 0.84 +/- 0.34 mm, P = .001); however, the estimated length of the original fibrous cap did not differ between the 2 rupture site groups (2.28 +/- 0.66 vs 2.11 +/- 0.69, P = not significant). In none of the patients did the remnants of the fibrous cap cover the entire mouth of the cavity. The estimated absolute length of the missing part of the fibrous cap correlated significantly with the cavity area (r = 0.517, P < .001), the lesion external elastic membrane area (r = 0.330, P = .016), the lumen area (r = 0.289, P = .036), the maximum plaque thickness (r = 0.364, P = .007), and the length of the estimated original fibrous cap (r = 0.709, P < .001). CONCLUSION: In general, the postrupture fibrous cap does not cover the entire mouth of the ruptured plaque cavity in its postrupture state. Potential explanations include the following: (1) part of the fibrous cap may be too thin to be visualized with IVUS, (2) part of it may have embolized, or (3) the prerupture fibrous cap may have been stretched and/or there were postrupture changes in lesion geometry.

Aged↗
PubMed2005

Effectiveness of the concomitant use of bivalirudin and drug-eluting stents (from the prospective, multicenter BivAlirudin and Drug-Eluting STents [ADEST] study).

Sirolimus-eluting stents (SESs) reduce restenosis compared with bare metal stents. Safety issues with drug-eluting stents are particularly important given concerns of possible increased thrombogenicity. Compared with heparin plus glycoprotein IIb/IIIa inhibitors, the direct thrombin inhibitor bivalirudin has been shown to reduce the risk of hemorrhagic complications in patients receiving bare metal stents, with similar efficacy in preventing ischemic complications. The safety and efficacy of percutaneous coronary intervention (PCI) with SESs and bivalirudin anticoagulation have not been prospectively studied. This prospective study performed at 9 United States hospitals evaluated 1,182 patients referred for PCI with SESs in whom the procedural anticoagulant was bivalirudin. Clopidogrel was administered before PCI in 79% of patients, and only 5.3% received procedural glycoprotein IIb/IIIa inhibitors. At 30 days, major adverse cardiac events occurred in 7.1% of patients, including 0.3% mortality, 4.4% myocardial infarction (defined as creatine kinase-MB >3x normal), 1.7% target vessel revascularization, and 0.6% stent thrombosis. Major bleeding occurred in only 0.8% of patients. Thus, use of bivalirudin as the procedural anticoagulant to support SES implantation in a "real world" population of patients undergoing PCI results in low rates of major adverse cardiac events, stent thrombosis, and major bleeding.

Angioplasty, Balloon, Coronary↗
PubMed2005

Impact of platelet glycoprotein IIb/IIIa Inhibition on the paclitaxel-eluting stent in patients with stable or unstable angina pectoris or provocable myocardial ischemia (a TAXUS IV substudy).

Whether the benefits that glycoprotein IIb/IIIa inhibitors confer in patients who undergo bare metal stent implantation extend to drug-eluting stents is unknown. We performed a prespecified subgroup analysis of the TAXUS IV study population to examine the effect of procedural glycoprotein IIb/IIIa inhibition during paclitaxel-eluting stent implantation on periprocedural creatine kinase-MB (CK-MB) levels. Glycoprotein (GP) IIb/IIIa inhibitors were administered to 57.7% of patients who had been randomized to receive the TAXUS stent and to 56.7% of those who had been randomized to receive the control stent. Among patients who received the TAXUS stent, the rate of CK-MB increases of >3 times the normal level was 2.6-fold higher in those who received a GP IIb/IIIa inhibitor than in those who did not (11.4% vs 4.4%, p = 0.0015). Composite rates of major adverse cardiac events and target vessel failure were also higher at 1 month in the GP IIb/IIIa group. By multivariate analysis, use of GP IIb/IIIa inhibitors during stenting with the TAXUS stent was an independent predictor of CK-MB increases >3 times the normal level. Further studies are warranted.

Abciximab↗
PubMed2005

Intravascular ultrasound study of patterns of calcium in ruptured coronary plaques.

Coronary calcium is intimately associated with coronary atherosclerotic plaque development, although it is controversial as to whether coronary calcium is associated with plaque instability. We analyzed 101 IVUS-detected ruptured plaques and compared them with 101 computer-matched control plaques without evidence of plaque rupture. The arc of calcium was measured every 0.5 mm within 10-mm-long segments that spanned the minimum lumen cross-sectional area, and the number and length of calcium deposits were assessed. Ruptured plaques had a significantly larger number of individual calcium deposits than control plaques (3.5 +/- 1.7 vs 1.8 +/- 1.1, p <0.001). However, the arc of the largest calcium deposit was smaller and the length of the largest calcium deposit in each plaque was shorter in ruptured plaques compared with control plaques (67.3 degrees +/- 41.4 degrees vs 114.9 degrees +/- 77.4 degrees , p <0.001, and 1.6 +/- 1.3 vs 4.0 +/- 2.7 mm, p <0.001, respectively). There was no difference in the number of superficial calcium deposits between the 2 groups, although ruptured plaques had significantly smaller arcs of superficial calcium compared with control plaques (56.2 degrees +/- 35.5 degrees vs 95.8 degrees +/- 65.2 degrees , p <0.001). Conversely, the number of deep calcium deposits was significantly larger in ruptured plaques than in control plaques (1.8 +/- 1.4 vs 0.3 +/- 0.6, p <0.001), although the arc of deep calcium was similar in the 2 groups. Ruptured plaques had quantitatively less calcium, especially superficial calcium, but a larger number of small calcium deposits, especially deep calcium deposits. In conclusion, ruptured plaques are associated with a larger number of calcium deposits within an arc of <90 degrees , a larger number of deep calcium deposits, and a remodeling index.

Aged↗
PubMed2005

Intravascular ultrasonic assessment of stent diameters derived from manufacturer's compliance charts.

We used intravascular ultrasound (IVUS) to assess the accuracy of manufacturers' stent balloon compliance charts. Many interventional cardiologists rely on manufacturers' compliance charts to select stent size and optimize stent diameters according to inflation pressures during percutaneous procedures. We randomly selected 212 patients who had de novo coronary lesions that had been treated with a single, bare metal, > or =3.0-mm stent (Bx velocity, NIR, TETRA/PENTA, S660/S670/S7) under IVUS guidance. Cases of stent overlap and postdilatation with another balloon were excluded. Predicted stent diameters were derived from each manufacturer's compliance charts, and stent size and final maximal deployment pressures were derived from each physician's report. IVUS-measured minimum stent diameters (range 1.4 to 4.0 mm, mean 2.79 +/- 0.48) were smaller than predicted diameters (range 3.1 to 4.57 mm, mean 3.79 +/- 0.44). The ratio of IVUS to predicted diameters ranged from 44% to 97% (mean 74 +/- 10%). This finding was common to all 3 stent sizes: 74 +/- 12% for 3.0 mm, 73 +/- 9% for 3.5 mm, and 74 +/- 9% for 4.0-mm stents (p = 0.9). This finding was also common to all 4 stent manufacturers, 72 +/- 8% for Boston Scientific, 76 +/- 11% for Guidant, 73 +/- 9% for Cordis, and 74 +/- 11% for Medtronic (p = 0.13), and to different stent lengths. Only 3.8% of the stents achieved 90% of the predicted minimum stent diameters, and only 24.6% achieved 80% of the predicted minimum stent diameters. In conclusion, in human coronary arteries, minimal stent diameter measured by IVUS is significantly smaller than that predicted by in vitro compliance charts. These differences are independent of stent manufacturer, length, diameter, and deployment pressure.

Aged↗
PubMed2005

Outcomes of paclitaxel-eluting stent implantation in patients with stenosis of the left anterior descending coronary artery.

OBJECTIVES: We sought to examine the efficacy of paclitaxel-eluting stent implantation in the left anterior descending coronary artery (LAD). BACKGROUND: Restenosis and recurrent cardiac events after percutaneous intervention are more common for lesions in the LAD than other native coronary arteries, and often necessitate bypass surgery. Drug-eluting stents may improve the long-term prognosis of this high-risk group. METHODS: In the TAXUS-IV trial, 1,314 patients with single de novo coronary lesions were assigned to implantation of the slow-release, polymer-based, paclitaxel-eluting TAXUS stent or an identical bare-metal stent; 536 (41%) randomized patients had LAD lesions. RESULTS: Baseline characteristics of patients with LAD lesions were well-matched between the randomized groups. Late lumen loss at nine months after paclitaxel-eluting and control stent implantation were 0.28 +/- 0.51 mm and 0.54 +/- 0.57 mm, respectively (p = 0.0004), and binary restenosis rates were 11.3% and 26.9%, respectively (p = 0.004). At one year, major adverse cardiac events (MACE) occurred in 13.5% of TAXUS-treated patients versus 21.2% treated with the control stent (p = 0.01). The need for bypass surgery at one year was reduced among patients randomized to the TAXUS stent (2.6% vs. 6.3%, p = 0.02). In the proximal LAD subgroup (n = 126), the one-year target vessel revascularization rate was 7.9% with the TAXUS stent and 18.6% with the bare-metal stent (p = 0.009). CONCLUSIONS: Compared to bare-metal stents, implantation of polymer-based, paclitaxel-eluting stents in LAD lesions is safe, and reduces angiographic restenosis and MACE one year. Notably, the need for bypass graft surgery due to restenosis is reduced after TAXUS stent implantation in LAD lesions.

Antineoplastic Agents↗
PubMed2005

Stent underexpansion and residual reference segment stenosis are related to stent thrombosis after sirolimus-eluting stent implantation: an intravascular ultrasound study.

OBJECTIVES: We sought to determine the predictors of stent thrombosis after sirolimus-eluting stent (SES) implantation. BACKGROUND: A number of cases of stent thrombosis have been reported after commercial release of the SES in the "real world," such that the U.S. Food and Drug Administration issued a warning. METHODS: Fifteen patients who developed stent thrombosis after successful SES implantation were analyzed and compared with 45 matched control patients who had no evidence of stent thrombosis. RESULTS: Minimum stent cross-sectional area (MSA) (4.3 +/- 1.6 mm(2) vs. 6.2 +/- 1.9 mm(2), p < 0.001) and stent expansion (0.65 +/- 0.18 vs. 0.85 +/- 0.14, p < 0.001) were significantly smaller in the stent thrombosis group than in the matched control patients. There was no significant difference in the rate of SES malapposition between the groups. However, the presence of a significant residual reference segment stenosis was more common in the stent thrombosis group compared with the matched control group (67% vs. 9%, p < 0.001). Independent predictors of stent thrombosis were stent underexpansion (p = 0.03) and a significant residual reference segment stenosis (p = 0.02). CONCLUSIONS: Stent underexpansion and residual reference segment stenosis are associated with stent thrombosis after successful SES implantation.

Aged↗
PubMed2005

Creatine kinase-MB enzyme elevation and long-term clinical events after successful coronary stenting in lesions with ruptured plaque.

Patients with acute coronary syndrome are at increased risk of acute and long-term events after stent implantation. We compared the impact of intravascular ultrasound detected plaque rupture on creatine kinase-MB (CK-MB) isoenzyme release and clinical outcomes by comparing 62 patients with ruptured plaques with 62 matched control patients who underwent stent implantation. Two thirds of the patients in each group presented with an acute coronary syndrome. There were no differences in procedural complications between groups, although patients with ruptured plaque had higher CK-MB elevation rates than those without ruptured plaque (1 to 3 times the upper limit of normal CK-MB, 35% vs 10%, p <0.001; >3 times the upper limit, 15% vs 2%, p = 0.02). Independent predictors of CK-MB elevation were presence of ruptured plaque (p = 0.03) and unstable angina (p = 0.04). Patients with ruptured plaque had higher composite rates of late events (target lesion revascularizations/myocardial infarctions/cardiac deaths) than controls (25% vs 9%, p = 0.03). These results were similar when only patients with acute coronary syndrome were studied. Plaque rupture morphology is associated with higher periprocedural CK-MB release and worse 1-year clinical outcome in patients treated with coronary stenting.

Analysis of Variance↗
PubMed2005

Contrast-induced nephropathy after percutaneous coronary interventions in relation to chronic kidney disease and hemodynamic variables.

We previously found that contrast-induced nephropathy (CIN) complicating percutaneous coronary intervention adversely affects patients with chronic kidney disease (CKD). Therefore, we further investigated whether the predictors and outcome of CIN after percutaneous coronary intervention differ among patients with versus without CKD. Among 7,230 consecutive patients, CIN (>or=25% or >or=0.5 mg/dl increase in preprocedure serum creatinine 48 hours after the procedure) developed in 381 of 1,980 patients (19.2%) with baseline CKD (estimated glomerular filtration rate [eGFR] <60 ml/min/1.73 m(2)) and in 688 of 5,250 patients (13.1%) without CKD. Decreased eGFRs, periprocedural hypotension, higher contrast media volumes, lower baseline hematocrit, diabetes, pulmonary edema at presentation, intra-aortic balloon pump use, and ejection fraction <40% were the most significant predictors of CIN in patients with CKD. Apart from intra-aortic balloon pump use, predictors of CIN in patients without CKD were the same as mentioned, plus older age and type of contrast media. Regardless of baseline renal function, CIN correlated with longer in-hospital stay and higher rates of in-hospital complications and 1-year mortality compared with patients without CIN. By multivariate analysis, CIN was 1 of the most powerful predictors of 1-year mortality in patients with preexisting CKD (odds ratio 2.37, 95% confidence interval 1.63 to 3.44) or preserved eGFR (odds ratio 1.78; 95% confidence interval 1.22 to 2.60). Thus, regardless of the presence of CKD, baseline characteristics and periprocedural hemodynamic parameters predict CIN, and this complication is associated with worse in-hospital and 1-year outcomes.

Aged↗
PubMed2005

Angiographic results of the first human experience with everolimus-eluting stents for the treatment of coronary lesions (the FUTURE I trial).

The purpose of this study was to report the angiographic findings of the first human evaluation of the everolimus-eluting stent (EES) for the treatment of noncomplex coronary lesions. Forty-two patients with de novo coronary lesions (2.75 to 4.00 mm vessels; lesion length, <18 mm) were prospectively randomized in a 2:1 ratio to receive either the EES (n = 27) or a metallic stent (n = 15). Baseline clinical and angiographic characteristics were similar among both groups. At 6-month follow-up, EES had a lower in-stent late lumen loss (0.10 +/- 0.22 vs 0.85 +/- 0.32 mm, p <0.0001) and in-segment diameter stenoses (20.7 +/- 12.3% vs 37.0 +/- 15.8%, p = 0.002). There was no in-stent restenosis with EES; however, 1 focal distal edge restenosis was present. There was 1 in-stent and 1 in-segment (proximal edge) restenosis in the metallic stent group. There was no stent thrombosis or aneurysm formation at follow-up in either group.

Aged↗
PubMed2005

Novel site-specific systemic delivery of Rapamycin with perfluorobutane gas microbubble carrier reduced neointimal formation in a porcine coronary restenosis model.

Earlier studies demonstrated that perfluorobutane gas microbubble carrier (PGMC) adheres to injured arteries and enhances the drug uptake specifically into the cells of the denuded vessel segment. The purpose of this study was to investigate the effect of PGMC-based systemic delivery of Rapamycin on expression of p27 in vascular tissue and restenosis in porcine coronary arteries after stent implantation. Eight pigs underwent coronary stent implantation (three stents per animal). Five pigs were treated with i.v. injection of PGMC with 2 mg of Rapamycin and three animals served as control. Four hours postprocedure, three pigs were sacrificed and stented segments were analyzed by high-performance liquid chromatography (HPLC) and Western blot. In chronic experiments, five pigs (15 stent sites) were sacrificed at 28 days following intervention and vessels were perfusion-fixed. HPLC of the treated arteries demonstrated high drug concentration in the vessel tissue, and Western blot analysis showed elevated expression of p27 at 4 hr postprocedure. Histomorphometry revealed significantly reduced (by 40%) neointimal formation in the PGMC/Rapamycin group compared with controls (1.84 +/- 0.84 vs. 4.77 +/- 1.71 mm2, respectively; P < 0.001). In the porcine coronary model, site-specific systemic delivery of Rapamycin utilizing PGMC resulted in overexpression of p27 and a significant reduction of neointimal formation within the stented segments.

Animals↗