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Biomedical subjects

Kenneth M Kent

Publications and source records attributed to Kenneth M Kent.

At least 55 records · Page 3Linked to original sources
PubMed2005

Three-year follow-up after intravascular gamma-radiation for in-stent restenosis in saphenous vein grafts.

The Washington Radiation for In-Stent Restenosis Trial in Saphenous Vein Grafts (SVG WRIST) demonstrated safety and efficacy of intravascular radiation therapy (IRT) for the treatment of in-stent restenosis (ISR) in SVG at 12 months. In this study, we aimed to examine whether the safety and efficacy of IRT is durable up to 36 months. One hundred twenty patients with diffuse ISR in SVG underwent balloon angioplasty, laser or atherectomy ablation, and/or additional stenting. After successful intervention, patients were randomly assigned in a double-blind fashion to intravascular treatment with a ribbon containing either iridium (Ir)-192 (n = 60) or nonradioactive seeds (n = 60). The prescribed dose at 2 mm from the source was either 14 or 15 Gy in vessels 2.5-4.0 mm or 18 Gy in vessels > 4.0 mm in diameter. At 36 months, target lesion revascularization (TLR; 43% vs. 66%; P = 0.02) and target lesion revascularization-major adverse cardiac event (TLR-MACE; 49% vs. 71%; P = 0.02) rates continued to be lower in the IRT group, but both target vessel revascularization (TVR; 59% vs. 71%; P = 0.17) and TVR-MACE (63% vs. 77%; P = 0.11) rates were not. In SVG WRIST, patients with ISR treated with IRT had a marked reduction in the need for repeat TLR at 36 months, with sustained clinical benefit at 3 years despite late recurrences, which were more pronounced in the radiation group.

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PubMed2005

Impact of sirolimus-eluting stents on outcomes of patients treated for acute myocardial infarction by primary angioplasty.

Sirolimus-eluting stents (SESs) are currently being used in patients undergoing percutaneous coronary intervention (PCI). SESs have not been evaluated in the treatment of acute myocardial infarction by primary angioplasty. We report our initial experience with SESs implanted during primary angioplasty. One hundred and three patients were treated within 12 hr after onset of acute myocardial infarction (AMI) with primary angioplasty and SES implantation. Those patients were compared to 504 patients treated with bare metal stents (BMSs). Angiographic success (TIMI flow grade 3 and residual stenosis < 50%) was completed in 98% of patients with SESs and no subacute stent thrombosis was reported. In-hospital outcomes were similar in the SES and BMS groups. At 6 months, major cardiac events were less frequent in the SES group than in the BMS group (9% vs. 24%, respectively; P < 0.001), driven by a lesser need for repeat revascularization with SESs (1% vs. 10.3% with BMSs; P = 0.014). Mortality at 6 months was 7% with SESs and 11% with BMSs (P = 0.14). SESs are safe and effective for the treatment of AMI by primary angioplasty. As compared to BMSs, SESs improve long-term outcome after AMI, mainly by reducing the need for repeat revascularization.

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PubMed2005

Selective versus exclusive use of sirolimus-eluting stent implantation in multivessel coronary artery disease.

Sirolimus-eluting stents (SESs; Cypher) have demonstrated a significant reduction in restenosis rates when compared to bare metal stents (BMSs). The purpose of this study was to evaluate the strategy of exclusive use of two SESs versus the combination of one BMS and one SES for two-vessel coronary artery disease (CAD). It was found that the selective use of one SES combined with one BMS in patients undergoing percutaneous coronary intervention that requires more than one stent is safe, feasible, and associated with favorable procedural, 30-day, and 6-month clinical outcomes when compared to the exclusive use of SESs.

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PubMed2005

Brachytherapy and bivalirudin evaluation study.

BACKGROUND: Bivalirudin is shown to be a competent substitute for heparin in percutaneous coronary intervention (PCI). The safety and efficacy of bivalirudin in patients undergoing PCI and vascular brachytherapy (VBT) are not known. This study aimed to assess the safety and efficacy of bivalirudin as a single antithrombotic agent in patients undergoing PCI and VBT. METHODS: A total of 152 patients enrolled in the Brachytherapy and Bivalirudin Evaluation Study underwent PCI and VBT with either gamma (n = 8) or beta radiation (n = 144). The main outcome measures were in-hospital events and 30-day clinical outcomes. All patients were treated with bivalirudin (0.75 mg/kg bolus and 1.75 mg/kg per hour infusion for beta radiation, 1 mg/kg bolus and 2.5 mg/kg per hour infusion for gamma radiation) as a single antithrombotic agent during the entire procedure. RESULTS: Baseline clinical and angiographic characteristics were similar between the 2 groups. More than 90% of the patients received beta radiation. In-hospital events showed a higher prevalence of acute procedural intracoronary thrombosis in patients treated with gamma- vs beta radiation (25% vs. 0.7%, P < .001). Thirty-day outcomes including death, Q-wave, and non-Q-wave myocardial infarctions, subacute stent thromboses, and repeat revascularizations were similar in both groups. CONCLUSION: Bivalirudin, as a single antithrombotic agent during PCI and VBT with beta emitters, may be used safely, but its use in the setting of PCI and gamma radiation may not be acceptable due to an increased incidence of acute procedural intracoronary thrombosis.

Angioplasty, Balloon, Coronary↗
PubMed2005

Impact of continued hospitalization in patients pre-treated with clopidogrel prior to coronary angiography and undergoing coronary artery bypass grafting.

Pre-treatment of patients with clopidogrel prior to coronary angiography (CAG) and possible percutaneous coronary intervention (PCI) is a standard practice. Candidates for coronary artery bypass surgery (CABG) are discharged or remain in the hospital until CABG after clopidogrel is discontinued. We investigated whether any differences exist in the rates of surgical complications and outcomes between these two groups of patients. We conclude that continued hospitalization of clopidogrel pre-treated patients does not confer any safety benefit with regard to post-operative complications and 30-day mortality. Discharging these patients after CAG may reduce hospitalization costs.

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PubMed2005

Drug-eluting stents versus repeat vascular brachytherapy for patients with recurrent in-stent restenosis after failed intracoronary radiation.

Recurrent in-stent restenosis (ISR) following intracoronary radiation therapy (IRT) continues to be a therapeutic challenge. The present study aims to evaluate the clinical outcomes of patients who were treated with drug-eluting stent (DES) implantation versus repeat IRT for recurrent ISR after brachytherapy failure. A cohort of 88 patients who were previously treated with brachytherapy for ISR and presented with angina and recurrence of angiographic restenosis were evaluated for treatment with either DES [sirolimus-eluting stents (SES) or paclitaxel-eluting stents (PES); n = 34] or percutaneous coronary intervention (PCI) and repeat radiation (gamma or beta radiation; n = 54). The two groups had similar baseline clinical and angiographic characteristics. The in-hospital outcomes were similar between both groups. At long-term follow-up of 9.7 +/- 4.1 months for the DES group and 10.3 +/- 3.5 months for the repeat IRT group, there were no deaths or myocardial infarctions (MI). There was a trend toward more target vessel revascularization-major adverse cardiac events (TVR-MACE) in the DES group (p = 0.09). In addition, the patients in the DES group had a significantly lower survival rate compared to those in the repeat IRT group (p = 0.018). For patients who had recurrent ISR following IRT, either DES implantation or repeat radiation is safe and is associated with excellent immediate outcomes. Yet, at long-term follow-up, repeat IRT was associated with less recurrences and need for repeat revascularization when compared to DES implantation. Therefore, repeat IRT should be considered as an option for this difficult patient subset.

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PubMed2004

Angiographic and clinical outcomes of late total occlusion versus treatment failure without late total occlusion in patients after intracoronary radiation therapy for in-stent restenosis.

This study aimed to compare the outcomes of patients with late total occlusion (LTO) versus patients with recurrence in the absence of LTO after intracoronary radiation therapy for in-stent restenosis. LTO, especially in the context of acute myocardial infarction, after intracoronary radiation therapy for in-stent restenosis, is associated with negative clinical outcomes after 6 and 12 months compared with in-stent restenosis without LTO.

Brachytherapy↗
PubMed2004

Bivalirudin versus heparin as an antithrombotic agent in patients treated with a sirolimus-eluting stent.

Bivalirudin (Angiomax) is increasingly used as a substitute for heparin in a variety of percutaneous coronary interventions. This retrospective, observational study aimed to evaluate the efficacy and safety of bivalirudin compared with heparin as an antithrombotic regimen in patients treated with sirolimus-eluting stents (Cypher) and found that bivalirudin is clinically safe and feasible, with fewer vascular and ischemic complications compared with heparin.

Anticoagulants↗
PubMed2004

Oral rapamycin to inhibit restenosis after stenting of de novo coronary lesions: the Oral Rapamune to Inhibit Restenosis (ORBIT) study.

OBJECTIVES: The aim of this study was to establish safety and feasibility of oral Rapamycin at two doses-2 mg and 5 mg-in achieving low rates of repeat target lesion revascularization (TLR) in de novo native coronary artery lesions. BACKGROUND: Drug-eluting stents have shown the ability to limit restenosis. Oral Rapamycin is an alternative strategy that can target multiple coronary lesions suitable for treatment with any approved metal stent and at potentially lower cost. METHODS: The Oral Rapamune to Inhibit Restenosis (ORBIT) study is an open-label study of 60 patients with de novo lesions treated with bare metal stents in up to two vessels. After a loading dose of 5 mg, patients received a daily dose of 2 mg (n = 30) and 5 mg (n = 30) for 30 days. Six-month angiographic, intravascular ultrasound (IVUS), and clinical follow-up were conducted. RESULTS: Baseline clinical and procedural characteristics were similar: 10% of patients in the 2-mg group and 30% in the 5-mg group did not complete the course; 43% in the 2-mg group and 66% in the 5-mg group had side effects. At six-month follow-up, late loss (0.6 +/- 0.5 mm vs. 0.7 +/- 0.5 mm; p = NS), in-stent binary restenosis (7.1% vs. 6.9%; p = NS), in-stent percent volume obstruction by IVUS (29% vs. 24%; p = NS), and clinically driven TLR (14.3% vs. 6.9%; p = NS) were similar in 2-mg and 5-mg groups. CONCLUSIONS: Oral Rapamycin for the prevention of restenosis is safe, feasible, and associated with low rates of repeat revascularization. Although associated with certain side effects, it may be considered for patients undergoing multivessel stents if proven in larger randomized studies.

Administration, Oral↗
PubMed2004

Value of monitoring activated clotting time when bivalirudin is used as the sole anticoagulation agent for percutaneous coronary intervention.

Anticoagulation during percutaneous coronary intervention (PCI) requires the monitoring of activated clotting time (ACT) to protect from periprocedural ischemic and bleeding complications; however, the optimal ACT values have not been established when PCI is performed with bivalirudin. After 495 consecutive patients treated for coronary artery disease with PCI received bivalirudin as a single anticoagulation agent, it was found that ACT is reproducible when bivalirudin is used during PCI and does not correlate with clinical events.

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PubMed2004

Impact of major side branch on periprocedural enzyme elevation and long-term outcome in patients undergoing percutaneous coronary intervention and brachytherapy for in-stent restenosis.

Side branch occlusion is 1 mechanism for the increase of creatine phosphokinase-MB after percutaneous coronary intervention and is associated with long-term adverse events. We studied 248 patients who underwent brachytherapy for in-stent restenosis with and without side branches, compared levels of creatine phosphokinase-MB with procedural, in-hospital, and long-term clinical outcomes, and found that patients with side branches have increased levels of creatine phosphokinase-MB after percutaneous coronary intervention and higher rates of restenosis, target vessel, and target lesion revascularization at 6-month follow-up.

Angioplasty, Balloon, Coronary↗
PubMed2004

Usefulness of periprocedural creatinine phosphokinase-MB release to predict adverse outcomes after intracoronary radiation therapy for in-stent restenosis.

We aimed to analyze periprocedural creatinine phosphokinase (CPK)-MB elevation in patients treated with intracoronary radiation therapy (IRT) for in-stent restenosis (ISR) to risk stratify these patients. The clinical significance of periprocedural CPK-MB elevation after IRT for ISR is unknown. An elevated CPK-MB has been associated with increased mortality after conventional angioplasty. We evaluated 1,326 patients who were enrolled in radiation trials for ISR at the Washington Hospital Center using gamma- and beta-emitters. Patients were analyzed according to degree of CPK-MB increase within 24 hours of the index IRT procedure (normal CPK-MB, CPK-MB 1 to 3 times the upper limit of normal, or CPK-MB >3 times the upper limit of normal). Patients with CPK-MB >3 times the upper limit of normal were older (64 +/- 12 years, p = 0.04), more likely to be smokers (64%, p = 0.04), hypertensive (85%, p <0.01), and diabetic (49%, p = 0.04). The cohort with the highest CPK-MB release (CPK-MB >3 times the upper limit of normal) had significantly higher rates of adverse clinical events at 12 months (major adverse cardiac events 40%, p <0.01), including death (9.3%, p <0.01) and late thrombosis (6.3%, p <0.01). Periprocedural CPK-MB elevation is of prognostic importance in patients treated with IRT for ISR, and its analysis appears to be mandatory to risk stratify these patients. The impact of glycoprotein IIb/IIIa antagonists in reducing periprocedural CPK-MB release awaits evaluation.

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PubMed2004

Five-year follow-up after intracoronary gamma radiation therapy for in-stent restenosis.

BACKGROUND: The Washington Radiation for In-Stent Restenosis Trial is a double-blinded randomized study evaluating the effects of intracoronary radiation therapy (IRT) in patients with in-stent restenosis (ISR). METHODS AND RESULTS: One hundred thirty patients with ISR (100 native coronary and 30 vein grafts) underwent percutaneous transluminal coronary angioplasty, laser ablation, rotational atherectomy, or additional stenting (36% of lesions). Patients were randomized to either 192-Iridium IRT or placebo, with a prescribed dose of 15 Gy to a 2-mm radial distance from the center of the source. Angiographic restenosis (27% versus 56%, P=0.002) and target vessel revascularization (26% versus 68%, P<0.001) were reduced at 6 months in patients treated with IRT. Between 6 and 60 months, patients treated with IRT compared with placebo had more target lesion revascularization (IRT, 21.6% versus placebo, 4.7%; P=0.04) and target vessel revascularization (IRT, 21.5% versus placebo, 6.1%; P=0.03). At 5 years, the major adverse cardiac event rate was significantly reduced with IRT (46.2% versus 69.2%, P=0.008). CONCLUSIONS: In the Washington Radiation for In-Stent Restenosis Trial, patients with ISR treated with IRT using 192-Iridium had a reduction in the need for repeat target lesion and vessel revascularization at 6 months and 5 years.

Cardiac Catheterization↗
PubMed2004

Effects of gamma radiation on the noninjured and unprotected left main.

The aim of this study was to evaluate the effect of gamma radiation on the noninjured, unprotected left main coronary artery. Noninjured vessel segments are often radiated during treatment of in-stent restenosis with PCI and gamma radiation. Angiographic analysis using QCA methods was performed on 55 left main arteries of patients (32 with radiation of the left main compared to 23 controls) who participated in the Washington Radiation for In-Stent Restenosis Trials (WRIST). Baseline demographics and follow-up were comparable between the two groups, concluding that gamma radiation with long radiation safety margins is feasible and safe. Gamma radiation of noninjured irradiated left main vessels when used to facilitate wide radiation margins for proximal irradiated injured LAD and LCx is safe and does not compromise the vessel integrity and its lumen.

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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

Use of IIb/IIIa inhibitors in patients with in-stent restenosis treated with intracoronary gamma-radiation. Integrilin WRIST.

The Integrilin Washington Radiation for In-Stent Restenosis Trial (WRIST) aimed to study the impact of IIb/IIIa inhibitors as adjunct therapy to intracoronary radiation therapy (IRT) for patients with in-stent restenosis (ISR). The impact of GP IIb/IIIa inhibitor (eptifibatide) as adjunct therapy to vascular brachytherapy using (192)Ir emitter was examined in patients with in-stent restenosis. In the study, 150 patients were assigned to eptifibatide (Integrilin) and 150 patients to heparin only. Clinical composite endpoints at 30 days were similar between the patients treated with and without eptifibatide (4.7% vs. 4.0%; P = 0.78). There was a similarity in the non-Q-wave myocardial infarction (MI) rates between the eptifibatide and the control group. Major bleeding was similar in patients treated with and without eptifibatide. Overall, the use of eptifibatide as adjunct therapy for patients with ISR that are treated with IRT did not impact the clinical outcome at 30 days.

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