PubMed Health⌕ Search

Biomedical subjects

Peter B Berger

Publications and source records attributed to Peter B Berger.

At least 73 records · Page 4Linked to original sources
PubMed2003

Clinical safety of magnetic resonance imaging early after coronary artery stent placement.

OBJECTIVES: Our aim was to examine the rate of adverse cardiac events in patients undergoing magnetic resonance imaging (MRI) <8 weeks after coronary stent placement. BACKGROUND: The risk of coronary stent thrombosis from dislodgement due to MRI early after stent placement is not well defined. Manufacturers recommend postponing MRI studies until eight weeks after coronary stent placement. METHODS: We analyzed the Mayo Clinic Rochester Percutaneous Coronary Intervention Database and examined records of 111 patients who underwent MRI <8 weeks after coronary stent placement treated with aspirin and a thienopyridine. Occurrence of death, myocardial infarction (MI), and repeat revascularization within 30 days of MRI were recorded. RESULTS: Magnetic resonance imaging (1.5 tesla) was performed within a median of 18 days (range, 0 to 54 days) after coronary stent placement. Four noncardiac deaths occurred, and three patients had repeat revascularization procedures. Stent thrombosis did not occur (95% confidence interval, 0% to 3.3%). CONCLUSIONS: Magnetic resonance imaging <8 weeks after coronary stent placement appears to be safe, and the risk of cardiac death or MI due to stent thrombosis is low. Postponing MRI does not appear to be necessary.

Aged↗
PubMed2003

Lack of adverse clopidogrel-atorvastatin clinical interaction from secondary analysis of a randomized, placebo-controlled clopidogrel trial.

BACKGROUND: Statins primarily metabolized by cytochrome P450 3A4 (CYP3A4) reportedly reduce clopidogrel's metabolism to active metabolite, thus attenuating its inhibition of platelet aggregation ex vivo. However, the clinical impact of this interaction has not been evaluated. METHODS AND RESULTS: Clopidogrel for the Reduction of Events During Observation (CREDO) was a double-blind, placebo-controlled, randomized trial comparing pretreatment (300 mg) and 1-year (75 mg/d) clopidogrel therapy (clopidogrel) with no pretreatment and 1-month clopidogrel therapy (75 mg/d) (control) after a planned percutaneous coronary intervention. All patients received aspirin. The 1-year primary end point was a composite of death, myocardial infarction, and stroke. We performed a post hoc analysis to evaluate the clinical efficacy of concomitant clopidogrel and statin administration, categorizing baseline statin use to those predominantly CYP3A4-metabolized (atorvastatin, lovastatin, simvastatin, and cerivastatin) (CYP3A4-MET) or others (pravastatin and fluvastatin) (non-CYP3A4-MET). Of the 2116 patients enrolled, 1001 received a CYP3A4-MET and 158 a non-CYP3A4-MET statin. For the overall study population, the primary end point was significantly reduced in the clopidogrel group (8.5% versus 11.5%, RRR 26.9%; P=0.025). This clopidogrel benefit was similar with statin use, irrespective of treatment with a CYP3A4-MET (7.6% clopidogrel, 11.8% control, RRR 36.4%, 95% CI 3.9 to 57.9; P=0.03) or non-CYP3A4-MET statin (5.4% clopidogrel, 13.6% control, RRR 60.6%, 95% CI -23.9 to 87.4; P=0.11). Patients given atorvastatin or pravastatin had similar 1-year event rates. Additionally, concomitant therapy with statins had no impact on major or minor bleeding rates. CONCLUSIONS: Although ex vivo testing has suggested a potential negative interaction when coadministering a CYP3A4-metabolized statin with clopidogrel, this was not clinically observed statistically in a post hoc analysis of a placebo-controlled study.

Angioplasty, Balloon, Coronary↗
PubMed2003

Frequency of stent thrombosis after acute coronary syndromes (from the SYMPHONY and 2nd SYMPHONY trials).

We studied stent thrombosis in 4,607 patients with acute coronary syndromes who received a coronary stent as part of routine care during 2 trials of aspirin versus sibrafiban for secondary prevention. In these patients, stent thrombosis occurred more often than in previous patients who underwent elective percutaneous coronary intervention. These patients and their outcomes may be more representative of patients with typical acute coronary syndromes undergoing stenting in clinical practice.

Acute Disease↗
PubMed2003

Clinical outcome of patients undergoing non-cardiac surgery in the two months following coronary stenting.

OBJECTIVES: We sought to determine the frequency and timing of complications at our institution when surgery was performed within two months of coronary stent placement. BACKGROUND: The optimal delay following coronary stent placement prior to non-cardiac surgery is unknown. METHODS: We analyzed the Mayo Clinic Percutaneous Coronary Intervention and Surgical databases between 1990 and 2000 and identified 207 patients who underwent surgery in the two months following successful coronary stent placement. RESULTS: Eight patients (4.0%) died or suffered a myocardial infarction or stent thrombosis. All 8 patients were among the 168 patients (4.8%, 95% confidence interval [CI] 2.1 to 9.2) undergoing surgery six weeks after stent placement; the frequency of these events ranged from 3.8% to 7.1% per week during each of the six weeks. No events occurred in the 39 patients undergoing surgery seven to nine weeks after stent placement (0%, 95% CI 0.0 to 9.0). CONCLUSIONS: These data suggest that, whenever possible, non-cardiac surgery should be delayed six weeks after stent placement, by which time stents are generally endothelialized, and a course of antiplatelet therapy to prevent stent thrombosis has been completed.

Aged↗
PubMed2003

Management of patients undergoing percutaneous coronary revascularization.

While performance of percutaneous coronary intervention (PCI) remains the domain of specialized cardiologists, patients undergoing PCI are cared for by noninvasive cardiologists, internists, and primary care physicians. Therefore, patient care is optimized when the entire patient care team understands procedural risks and complications as well as optimum patient management before, during, and after PCI. Before PCI, patients with contrast dye allergies should be identified and pretreated with steroids and an H1-blocker. Hydration should be initiated and maintained before and after the procedure to minimize the risks for contrast nephropathy. Periprocedure, patients should be monitored clinically for evidence of ischemia. In patients with significant groin, flank, abdominal, or back pain, as well as those with decrease in hematocrit or unexplained hypotension, the diagnosis of groin or retroperitoneal hematoma should be considered and promptly evaluated. Groin tenderness, pulsatile mass, or bruit should prompt evaluation for possible femoral pseudoaneurysm or arteriovenous fistulae. After the procedure, all patients treated with coronary stents should receive aspirin plus clopidogrel. Patients who develop typical anginal symptoms between the 1st and 6th to 8th months after PCI are likely to have restenosis and can be evaluated by an imaging study or repeated catheterization.

Angioplasty, Balloon, Coronary↗
PubMed2003

Treatment of saphenous vein bypass grafts with ultrasound thrombolysis: a randomized study (ATLAS).

BACKGROUND: Percutaneous coronary interventions (PCIs) in saphenous vein grafts (SVGs) with thrombus have a high frequency of distal embolization. Acolysis (therapeutic ultrasound) can break up thrombus in vitro in animal models and humans. Whether this is beneficial during percutaneous SVG interventions is unknown. METHODS AND RESULTS: We performed a trial of coronary ultrasound thrombolysis in which patients with an acute coronary syndrome undergoing PCI in SVGs were randomly assigned to receive acolysis or abciximab. The primary end point was a successful procedure, defined as final luminal diameter stenosis 30% or less with Thrombolysis In Myocardial Infarction grade 3 flow and freedom from major adverse cardiac events (composite of death, Q-wave, and non-Q-wave myocardial infarction [MI], emergency bypass procedure, disabling stroke, and target lesion revascularization). Of 181 enrolled, 92 received acolysis and 89 abciximab. Angiographic procedural success was achieved in 63% of acolysis patients and 82% of abciximab patients (P=0.008). Incidence of major adverse cardiac events at 30 days was 25% with acolysis and 12% with abciximab (P=0.036), attributable mainly to a greater frequency of non-Q-wave MI with acolysis (19.6% versus 7.9%, P=0.03). The incidence of Q-wave MI was also higher with acolysis (5.4% versus 2.2%, P=nonsignificant). The primary end point was achieved in 53.8% of acolysis patients and 73.1% of abciximab patients (P=0.014). CONCLUSIONS: Use of therapeutic ultrasound in vein graft lesions in patients with acute coronary syndrome had poor angiographic outcome and increased the incidence of acute ischemic complications.

Abciximab↗
PubMed2003

Safety of abciximab in patients with chronic renal insufficiency who are undergoing percutaneous coronary interventions.

BACKGROUND: Patients with chronic renal insufficiency (CRI) have worse outcomes during and after percutaneous coronary interventions (PCI). Abciximab reduces complications, but may cause excessive bleeding in patients with CRI. Therefore, we sought to determine the safety of abciximab in patients with CRI. METHODS: Patients (n = 4158) undergoing PCI at the Mayo Clinic since abciximab became available were analyzed according to their estimated creatinine clearance (> or =70, 50-69, or <50 mL/min) or need for dialysis. Major bleeding was defined as a cerebrovascular bleed or a decrease in the hematocrit level >15%. Minor bleeding was defined as a decrease in the hematocrit level of 10% to 15% with an identifiable site of bleeding. RESULTS: CRI was associated with increased bleeding in patients who received abciximab and patients who did not. However, there was only a trend toward an interaction between creatinine clearance and major bleeding with abciximab (odds ratio [OR], 1.18; P =.06) and no interaction with minor bleeding (OR, 1.01; P =.94) or any bleeding (OR, 1.10; P =.15). CONCLUSION: CRI is associated with an increased risk of bleeding complications after PCI. Although abciximab increases the risk of bleeding in all patients, the increase in relative risk is not significantly greater in patients with CRI. Thus, abciximab may be given safely in patients with CRI who are undergoing PCI.

Abciximab↗
PubMed2003

Methylenetetrahydrofolate reductase (MTHFR) 677C>T and methionine synthase reductase (MTRR) 66A>G polymorphisms: association with serum homocysteine and angiographic coronary artery disease in the era of flour products fortified with folic acid.

We analyzed the association between the methylenetetrahydrofolate reductase (MTHFR) 677C>T and methionine synthase reductase (MTRR) 66A>G polymorphisms with serum homocysteine and with coronary artery disease (CAD) in 504 patients undergoing clinically-indicated angiography between July 1998 and January 1999. Significant CAD (>/=50% stenosis in >/=one artery, blinded to risk factors) was present in 271 patients (54%). Median homocysteine (micromol/l) was 8.8 (interquartile range: 7.5-10.7). The prevalence of the MTHFR TT, CT, and CC genotypes was 11, 44 and 45%, respectively. Median tHcy (with interquartile ranges) for the entire population was 8.8 (7.5-10.7), and for the TT, CT, and CC genotypes was 9.7 (8.2-11.4), 8.8 (7.5-10.7), and 8.6 (7.3-10.6) micromol/l, respectively (P=0.04). On multiple logistic regression analysis, the MTHFR TT genotype was associated with hyperhomocysteinemia (adjusted OR=3.57; 95% CI, 1.47-8.70), but not with significant CAD. The prevalence of the MTRR AA, AG, GG genotypes was 19, 50 and 31%, respectively. There were no differences in mean homocysteine, prevalence of hyperhomocysteinemia and significant CAD between the three genotypes. On multivariate analysis, the MTRR genotypes were not associated with serum homocysteine or with significant CAD.

Adenine↗
PubMed2002

Hyperhomocysteinemia accelerates atherosclerosis in cystathionine beta-synthase and apolipoprotein E double knock-out mice with and without dietary perturbation.

Although hyperhomocysteinemia is an independent risk factor for cardiovascular disease, a direct role for homocysteine (Hcy) in this disease remains to be shown. Whereas diet-induced hyperhomocysteinemia promotes atherosclerosis in animal models, the effects of Hcy on atherogenesis in the absence of dietary perturbations is not known. We have generated double knock-out mice with targeted deletions of the genes for apolipoprotein E (apoE) and cystathionine beta-synthase (CBS), which converts Hcy to cystathionine. ApoE(-/-)/CBS(-/-) mice developed aortic lesions even in the absence of dietary manipulation; lesion area and lesion cholesteryl ester (CE) and triglyceride (TG) contents increased with animal age and plasma Hcy levels. Plasma total cholesterol was significantly increased, whereas high density lipoprotein (HDL) cholesterol and TG concentrations of apoE(-/-)/CBS(-/-) mice were decreased. Cholesterol esterification and activities of enzymes catalyzing CE or TG formation in the vessel wall and in peritoneal macrophages were not changed by hyperhomocysteinemia. However, uptake of human acetyl-LDL, but not native low density lipoprotein (LDL), by mouse peritoneal macrophages was higher in the presence of hyperhomocysteinemia. These results suggest that isolated hyperhomocysteinemia is atherogenic and alters hepatic and macrophage lipoprotein metabolism, in part, by enhancing uptake of modified LDL.

Animals↗
PubMed2002

Early and sustained dual oral antiplatelet therapy following percutaneous coronary intervention: a randomized controlled trial.

CONTEXT: Following percutaneous coronary intervention (PCI), short-term clopidogrel therapy in addition to aspirin leads to greater protection from thrombotic complications than aspirin alone. However, the optimal duration of combination oral antiplatelet therapy is unknown. Also, although current clinical data suggest a benefit for beginning therapy with a clopidogrel loading dose prior to PCI, the practical application of this therapy has not been prospectively studied. OBJECTIVES: To evaluate the benefit of long-term (12-month) treatment with clopidogrel after PCI and to determine the benefit of initiating clopidogrel with a preprocedure loading dose, both in addition to aspirin therapy. DESIGN, SETTING, AND PARTICIPANTS: The Clopidogrel for the Reduction of Events During Observation (CREDO) trial, a randomized, double-blind, placebo-controlled trial conducted among 2116 patients who were to undergo elective PCI or were deemed at high likelihood of undergoing PCI, enrolled at 99 centers in North America from June 1999 through April 2001. INTERVENTIONS: Patients were randomly assigned to receive a 300-mg clopidogrel loading dose (n = 1053) or placebo (n = 1063) 3 to 24 hours before PCI. Thereafter, all patients received clopidogrel, 75 mg/d, through day 28. From day 29 through 12 months, patients in the loading-dose group received clopidogrel, 75 mg/d, and those in the control group received placebo. Both groups received aspirin throughout the study. MAIN OUTCOME MEASURES: One-year incidence of the composite of death, myocardial infarction (MI), or stroke in the intent-to-treat population; 28-day incidence of the composite of death, MI, or urgent target vessel revascularization in the per-protocol population. RESULTS: At 1 year, long-term clopidogrel therapy was associated with a 26.9% relative reduction in the combined risk of death, MI, or stroke (95% confidence interval [CI], 3.9%-44.4%; P =.02; absolute reduction, 3%). Clopidogrel pretreatment did not significantly reduce the combined risk of death, MI, or urgent target vessel revascularization at 28 days (reduction, 18.5%; 95% CI, -14.2% to 41.8%; P =.23). However, in a prespecified subgroup analysis, patients who received clopidogrel at least 6 hours before PCI experienced a relative risk reduction of 38.6% (95% CI, -1.6% to 62.9%; P =.051) for this end point compared with no reduction with treatment less than 6 hours before PCI. Risk of major bleeding at 1 year increased, but not significantly (8.8% with clopidogrel vs 6.7% with placebo; P =.07). CONCLUSIONS: Following PCI, long-term (1-year) clopidogrel therapy significantly reduced the risk of adverse ischemic events. A loading dose of clopidogrel given at least 3 hours before the procedure did not reduce events at 28 days, but subgroup analyses suggest that longer intervals between the loading dose and PCI may reduce events.

Administration, Oral↗
PubMed2002

Frequency and correlates of coronary stent thrombosis in the modern era: analysis of a single center registry.

OBJECTIVES: The study examined the frequency, correlates, and outcome of patients with stent thrombosis within 30 days of stent placement. BACKGROUND: Patients in trials evaluating stents or dual antiplatelet therapy to prevent coronary stent thrombosis have generally had narrow inclusion criteria; the extent to which stent thrombosis rates in such trials represent current practice, particularly with the availability of newer stents, is unclear. METHODS: We performed a retrospective analysis of the Mayo Clinic Percutaneous Coronary Intervention database and identified all patients who received at least one coronary stent and dual antiplatelet therapy (aspirin and ticlopidine or clopidogrel for two to four weeks). RESULTS: Four thousand five hundred nine patients underwent successful coronary stent implantation and were treated with dual antiplatelet therapy between July 1, 1994, and April 30, 2000. Stent thrombosis occurred in 23 patients (0.51%; 95% confidence interval 0.32%, 0.76%) within 30 days of stent placement. Multivariate analysis using bootstrap model selection to avoid over-fitting the model indicated that only the number of stents placed was an independent correlate of stent thrombosis (odds ratio 1.80, p < 0.001). The frequency of death and frequency of nonfatal myocardial infarction (MI) among the 23 patients with stent thrombosis were 48% and 39%, respectively. CONCLUSIONS: Stent thrombosis is even more rare in the current era than in earlier trials. Number of stents placed was an independent correlate of stent thrombosis. Most patients who suffer stent thrombosis either die or suffer MI.

Aged↗
PubMed2002

Rationale for on-site cardiac surgery for primary angioplasty: a time for reappraisal.

Since the early 1990s, with significant improvement in the procedural success of percutaneous coronary interventions (PCIs), there has been a concomitant reduction in the need for emergency coronary artery bypass graft surgery. This review article focuses on the need for on-site cardiac surgery in patients with acute myocardial infarction undergoing primary angioplasty at centers without on-site cardiac surgical backup. It gives an overview of the need for emergency bypass surgery in both the large trial setting and the community hospital setting. Special consideration is also given to the risks and benefits of primary angioplasty compared with thrombolytic therapy, transfer to an institution with an on-site cardiac surgical facility compared with primary PCI, the frequency and indications for emergency cardiac surgery related and unrelated to primary angioplasty and the requirements for primary angioplasty that must be met in hospitals without the capability of on-site cardiac surgery.

Angioplasty, Balloon, Coronary↗
PubMed2002

Incidence and prognostic importance of acute renal failure after percutaneous coronary intervention.

BACKGROUND: In patients undergoing percutaneous coronary intervention (PCI) in the modern era, the incidence and prognostic implications of acute renal failure (ARF) are unknown. METHODS AND RESULTS: With a retrospective analysis of the Mayo Clinic PCI registry, we determined the incidence of, risk factors for, and prognostic implications of ARF (defined as an increase in serum creatinine [Cr] >0.5 mg/dL from baseline) after PCI. Of 7586 patients, 254 (3.3%) experienced ARF. Among patients with baseline Cr <2.0, the risk of ARF was higher among diabetic than nondiabetic patients, whereas among those with a baseline Cr >2.0, all had a significant risk of ARF. In multivariate analysis, ARF was associated with baseline serum Cr, acute myocardial infarction, shock, and volume of contrast medium administered. Twenty-two percent of patients with ARF died during the index hospitalization compared with only 1.4% of patients without ARF (P<0.0001). After adjustment, ARF remained strongly associated with death. Among hospital survivors with ARF, 1- and 5-year estimated mortality rates were 12.1% and 44.6%, respectively, much greater than the 3.7% and 14.5% mortality rates in patients without ARF (P<0.0001). CONCLUSIONS: The overall incidence of ARF after PCI is low. Diabetic patients with baseline Cr values <2.0 mg/dL are at higher risk than nondiabetic patients, whereas all patients with a serum Cr >2.0 are at high risk for ARF. ARF was highly correlated with death during the index hospitalization and after dismissal.

Acute Kidney Injury↗