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R J Gibbons

Publications and source records attributed to R J Gibbons.

At least 19 recordsLinked to original sources
PubMed2001

Guidelines for the management of patients with chronic stable angina: treatment.

The dual aims of treating patients with chronic stable angina are 1) to reduce morbidity and mortality and 2) to eliminate angina with minimal adverse effects and allow the patient to return to normal activities. In the absence of contraindications, beta-blockers are recommended as initial therapy. All beta-blockers seem to be equally effective. If the patient has serious contraindications to beta-blockers, unacceptable side effects, or persistent angina, calcium antagonists should be administered. Long-acting dihydropyridine and nondihydropyridine agents are generally as effective as beta-blockers in relieving angina. Long-acting nitrates are considered third-line therapy because a nitrate-free interval is required to avoid developing tolerance. All long-acting nitrates seem to be equally effective. Patients with angina should take 75 to 325 mg of aspirin daily unless they have contraindications. Such risk factors as smoking, elevated low-density lipoprotein cholesterol level, diabetes, and hypertension should be treated appropriately. Coronary revascularization has not been shown to improve survival for most patients with chronic angina but may be required to control symptoms. However, coronary artery bypass grafting (CABG) is often indicated for symptomatic patients with left-main disease, three-vessel disease, or two-vessel disease including proximal stenosis of the left anterior descending coronary artery; it improves their survival. Percutaneous transluminal coronary angioplasty is an alternative to CABG for patients with normal left ventricular function and favorable angiographic features. Coronary artery bypass grafting is initially more effective in relieving angina than medical therapy, but the two procedures yield similar results after 5 to 10 years. Eighty percent of patients who undergo CABG remain angina-free 5 years after surgery. In low-risk patients, percutaneous transluminal coronary angioplasty seems to control angina better than medical therapy, but recurrent angina and repeated procedures are more likely than with CABG. Patient education is an important component of management. Long-term follow-up should be individualized to ascertain clinical stability at regular intervals and to reassess prognosis when warranted.

Adrenergic beta-Antagonists↗
PubMed2001

Guidelines for the management of patients with chronic stable angina: diagnosis and risk stratification.

Patients with suspected chronic stable angina can be evaluated in three stages. In stage one, the clinician uses information from the history, physical examination, laboratory tests for diabetes and hyperlipidemia, and resting electrocardiography to estimate the patient's probability of coronary artery disease (CAD). In stage two, additional testing for patients with a low probability of CAD focuses on diagnosing noncoronary causes of chest pain. Patients with a high probability of CAD have stress tests to assess their risk from CAD, and patients with an intermediate probability of CAD have stress tests to estimate the probability of CAD and assess their risk from CAD. Most patients with new-onset angina can start stress testing with exercise electrocardiography. The initial stress test should be a stress imaging procedure for patients with rest ST-segment depression greater than 1 mm, complete left bundle-branch block, ventricular paced rhythm, preexcitation syndrome, or previous revascularization with percutaneous coronary angioplasty or coronary artery bypass grafting. Patients who cannot exercise can have an imaging procedure with stress induced by pharmacologic agents. In stage three, patients with a predicted average annual cardiac mortality rate between 1% and 3% should have a stress imaging study or coronary angiography with left ventriculography. Those with a known left ventricular dysfunction should have cardiac catheterization. Patients with CAD who have an estimated annual mortality rate greater than 3% should have cardiac catheterization to determine whether their anatomy is suitable for revascularization. Patients with an estimated annual mortality rate less than 1% can begin to receive medical therapy.

Algorithms↗
PubMed2001

An anti-CD11/CD18 monoclonal antibody in patients with acute myocardial infarction having percutaneous transluminal coronary angioplasty (the FESTIVAL study).

Maximal benefits of coronary reperfusion after acute myocardial infarction (AMI) with ST-segment elevation may be attenuated by neutrophil-mediated reperfusion injury. Inflammatory mediators released from potentially viable myocytes cause activation of neutrophils, which traverse the endothelium and enter the myocardium. This process involves interaction between the neutrophil-expressed CD11/CD18 and endothelial-expressed intercellular adhesion molecule-1 (ICAM-1). Preclinical studies have shown that monoclonal antibodies (MAb) to CD18 can limit infarct size and preserve left ventricular function. We sought to determine the initial clinical safety and tolerability of Hu23F2G (LeukArrest), a humanized MAb to CD11/CD18, in patients with AMI who underwent percutaneous transluminal coronary angioplasty (PTCA). Sixty patients with AMI were randomized to low- (0.3 mg/kg) or high-dose (1.0 mg/kg) Hu23F2G or to placebo immediately before PTCA. We found no clinically significant differences in vital signs, physical examination, laboratory evaluation, or need for subsequent cardiac interventions. In Hu23F2G treatment groups, serum concentration of Hu23F2G increased rapidly to 3,234 +/- 1,298 microg/L (low-dose group) and 15,558 +/- 4409 microg/L (high-dose group) between 5 and 60 minutes, then declined over 72 hours to near-baseline values. Myocardial single-photon emission computed tomographic imaging 120 to 260 hours after PTCA showed no statistically significant differences in final left ventricular defect size. Hu23F2G was well tolerated, with no increase in adverse events, including infections. Thus, Hu23F2G appears safe and well tolerated in patients undergoing PTCA for AMI.

Aged↗
PubMed2001

Assessment of the exercise electrocardiogram in women versus men using tomographic myocardial perfusion imaging as the reference standard.

The exercise electrocardiogram (ECG) is widely believed to be less accurate in women, primarily due to a high prevalence of false-positive tests. The purpose of this study was to examine the relative accuracy of the exercise ECG in women versus men in 8,671 patients (3,213 women, 5,458 men) using myocardial perfusion imaging as the reference standard. More women (14%) than men (10%) had a false-positive ECG (p <0.001), but the absolute difference was relatively small. The false-negative rate was considerably lower in women (17% vs 32%, p <0.001). Compared with men, women had lower test sensitivity (30% vs 42%, p <0.001) and positive predictive value (34% vs 70%, p <0.001) but higher specificity (82% vs 78%, p = 0.002), negative predictive value (78% vs 52%, p <0.001), and accuracy (69% vs 58%, p <0.001). In patients with a false-negative exercise ECG, "high-risk" scans were less prevalent in women (12% vs 19%, p <0.001). In the smaller subset of patients referred for coronary angiography (205 women, 838 men), the false-positive electrocardiographic rate was again higher in women (13% vs 7%, p = 0.003), but neither specificity (69% vs 74%, p = NS) nor accuracy (60% vs 66%, p = NS) was different between the sexes. Thus, the percentage of patients with a false-positive exercise ECG was higher in women than men but low in absolute terms (<15%) for both sexes. Test specificity was not lower in women. These results suggest that gender should not be a major determinant for selecting stress imaging over standard treadmill testing.

Coronary Artery Disease↗
PubMed2001

Similarity of ventricular function in patients alive 5 years after randomization to surgery or angioplasty in the BARI trial.

BACKGROUND: Left ventricular ejection fraction (LVEF) is a recognized determinant of survival in patients with coronary artery disease. In major trials comparing surgical and percutaneous revascularization approaches, the long-term effect of the coronary revascularization strategy on LVEF has not been reported. METHODS AND RESULTS: In the NHLBI-sponsored Bypass and Angioplasty Revascularization Investigation (BARI) randomized trial comparing angioplasty and bypass surgery as initial treatment strategies, 1220 (75%) of the 1617 surviving randomized patients had their EF measured by radionuclide ventriculography 5 years after study entry. For the total study group, the 5-year EF in the CABG group (n=623) was 55.8+/-12.3, compared with 55.7+/-12.7 in PTCA group (n=597, P:=0.82). There was no significant difference in measured EF between the CABG group and the PTCA group within multiple subgroups determined by the presence or absence of diabetes, 3-vessel disease, complete revascularization, or prior myocardial infarction. In a multiple linear regression model developed to predict 5-year EF, treatment assignment to PTCA or CABG was not significant (P:=0.95). If an EF of 0 was imputed for patients who were dead and missing EF data, however, there was a higher EF in the CABG group (P:=0.0018) among diabetic patients only. CONCLUSIONS: In the BARI randomized trial, initial treatment assignment to angioplasty was not associated with any difference in long-term ventricular function compared with initial treatment assignment to surgery. These results apply, however, only to patients who were alive at 5 years.

Angioplasty↗
PubMed2001

Impact of right ventricular involvement on mortality and morbidity in patients with inferior myocardial infarction.

OBJECTIVES: We sought to evaluate the prognostic impact of right ventricular (RV) myocardial involvement in patients with inferior myocardial infarction (MI). BACKGROUND: There is uncertainty regarding the risk of major complications in patients with inferior MI complicated by RV myocardial involvement. Whether these complications are related to RV myocardial involvement itself or simply to the extent of infarction involving the left ventricle (LV) is also unknown. METHODS: We examined the incidence of death and mechanical and electrical complications in patients with (n = 491) and without (n = 638) RV myocardial involvement and in patients with anterior MI (n = 971) in an analysis from the Collaborative Organization for RheothRx Evaluation (CORE) trial. Left ventricular infarct size was assessed by technetium-99m-sestamibi single-photon emission computed tomography and peak creatine kinase, and LV function was assessed by radionuclide angiography. We also performed a meta-analysis in which we pooled the results of our study with previous smaller studies addressing the same question. RESULTS: Six-month mortality was 7.8% in inferior MI compared with 13.2% in anterior MI. Among patients with inferior MI, serious arrhythmias were significantly more common in patients with RV myocardial involvement who also had a trend toward higher mortality, pump failure and mechanical complications. However, this was not associated with a difference in LV infarct size or function. A meta-analysis of six studies (n = 1,198) confirmed that RV myocardial involvement was associated with an increased risk of death (odds ratio [OR] 3.2, 95% confidence interval [CI] 2.4 to 4.1), shock (OR 3.2, 95% CI 2.4 to 3.5), ventricular tachycardia or fibrillation (OR 2.7, 95% CI 2.1 to 3.5) and atrioventricular block (OR 3.4, 95% CI 2.7 to 4.2). CONCLUSIONS: Patients with inferior MI who also have RV myocardial involvement are at increased risk of death, shock and arrhythmias. This increased risk is related to the presence of RV myocardial involvement itself rather than the extent of LV myocardial damage.

Arrhythmias, Cardiac↗
PubMed2001

Risk stratification after successful coronary revascularization: the lack of a role for routine exercise testing.

OBJECTIVE: The objective of this study was to evaluate the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for exercise testing (EXT) after successful coronary revascularization (CR) using the Bypass Angioplasty Revascularization Investigation experience. BACKGROUND: The ACC/AHA guidelines state that EXT within three years of successful CR is not useful. METHODS: The 1,678 patients randomized to CR by either angioplasty or bypass surgery were required to take symptom-limited treadmill tests one, three and five years after revascularization. RESULTS: Patients who took the test at each specified time had a much lower subsequent two-year mortality than those who did not (1.9% vs. 9.4%, 3.5% vs. 12.6% and 3.3% vs. 11.0% at one, three and five years, respectively, after CR [p < 0.0001 for each]). Exercise parameters at the one- and three-year test did not improve a multivariable model of survival after including clinical parameters. Exercising to Bruce stage 3 or generating a Duke score >-6 were independently predictive of two-year survival after the five-year test. ST depression on the one-year test was associated with more revascularizations (relative risk = 1.6; p < 0.001). CONCLUSIONS: Patients with stable multivessel coronary disease who took a protocol-mandated exercise test at one, three and five years after revascularization were at low risk for mortality in the two years subsequent to each test. Exercise parameters did not improve prediction of mortality in the two years after the one- and three-year tests. The ACC/AHA guidelines on exercise testing after CR (no value for routine testing in stable patients for three years after revascularization) are supported by these results.

Angioplasty, Balloon, Coronary↗
PubMed2001

Gender differences and temporal trends in clinical characteristics, stress test results and use of invasive procedures in patients undergoing evaluation for coronary artery disease.

OBJECTIVES: This study examined gender differences and temporal changes in the clinical characteristics of patients referred for nuclear stress imaging, their imaging results and subsequent utilization of coronary angiography and revascularization. BACKGROUND: Gender bias may influence resource utilization in patients with coronary artery disease (CAD). No study has analyzed gender differences and time trends in patients referred for noninvasive testing and subsequent use of invasive procedures. METHODS: Between January 1986 and December 1995, 14,499 patients (5,910 women and 8,589 men) without established CAD underwent stress myocardial perfusion imaging. The clinical characteristics, imaging results, coronary angiograms and revascularization outcomes were compared in women and men over time. RESULTS: The mean pretest probability of CAD was lower in women (45%) than in men (70%) (p < 0.001). More women (69%) than men (42%) had normal nuclear images (p < 0.001). Men (17%) were more likely than women (8%) to undergo coronary angiography (p < 0.001). Male gender was independently associated with referral for coronary angiography (multivariate model: chi-square = 16, p < 0.001) but was considerably weaker than the imaging variables (summed reversibility score: chi-square = 273, p < 0.001). Revascularization was performed in more men (46% of the population undergoing angiography) than women (39%) (p = 0.01), but gender was not independently associated with referral to revascularization. There were no significant differences in clinical, imaging or invasive variables between the genders over time. CONCLUSIONS: There was little evidence for a bias against women in this study. Women were somewhat less likely to undergo coronary angiography but were referred for stress perfusion imaging more liberally. Practice patterns remained constant over this 10-year period.

Angioplasty, Balloon, Coronary↗
PubMed2001

ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation: executive summary. A Report of the American College of Cardiology/ American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients With Atrial Fibrillation): developed in Collaboration With the North American Society of Pacing and Electrophysiology.

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Algorithms↗
PubMed2001

Monosomy for the most telomeric, gene-rich region of the short arm of human chromosome 16 causes minimal phenotypic effects.

We have examined the phenotypic effects of 21 independent deletions from the fully sequenced and annotated 356 kb telomeric region of the short arm of chromosome 16 (16p13.3). Fifteen genes contained within this region have been highly conserved throughout evolution and encode proteins involved in important housekeeping functions, synthesis of haemoglobin, signalling pathways and critical developmental pathways. Although a priori many of these genes would be considered candidates for critical haploinsufficient genes, none of the deletions within the 356 kb interval cause any discernible phenotype other than alpha thalassaemia whether inherited via the maternal or paternal line. These findings contrast with previous observations on patients with larger (> 1 Mb) deletions from the 16p telomere and therefore address the mechanisms by which monosomy gives rise to human genetic disease.

Adolescent↗
PubMed2001

Use of a new myocardial centroid for measurement of regional myocardial dysfunction by electron beam computed tomography: comparison with technetium-99m sestamibi infarct size quantification.

RATIONALE AND OBJECTIVES: The study compared the performance of conventional endocardial and epicardial centroid algorithms with the new "myocardial" centroid algorithm in patients with anterior myocardial infarction. "Floating" endocardial or epicardial centroid algorithms, commonly used in tomographic imaging methods to assess regional motion, may misrepresent left ventricular regional myocardial function in the presence of markedly asymmetric left ventricular contraction. METHODS: A new centroid algorithm based on regional myocardial mass distribution was tested in 29 patients with a first anterior myocardial infarction and was compared with conventional centroid algorithms. Direct comparisons in 60 equal sectors at one midventricular level per patient were performed between electron beam computed tomography and technetium-99m sestamibi single-photon emission computed tomography. The thresholds of regional myocardial function used to define infarction were varied for regional ejection fraction from 20% to 40% and for regional wall thickening from 0 to 4 mm. Regression and Bland-Altman analysis were used to compare infarct size by regional myocardial function with infarct size by sestamibi single-photon emission computed tomography. RESULTS: The new myocardial centroid showed the least shift toward infarcted myocardium from diastole to systole and had the highest amplitudes of the measurement curves for regional ejection fraction and regional wall thickening. The optimal regional myocardial function thresholds for each centroid algorithm for regional ejection fraction were endocardial, 30% (R = 0.62; mean difference to sestamibi, -0.5% +/- 22.1% tomographic infarct size points); epicardial, 30% (R = 0.79; mean difference, 2.2% +/- 13.1% tomographic infarct size points); and new myocardial, 25% (R = 0.88; mean difference, -0.6% +/- 9.5% tomographic infarct size points). The optimal thresholds for regional wall thickening were endocardial, 1 mm (R = 0.70; mean difference, -2.2% +/- 14.3% tomographic infarct size points); epicardial, 1 mm (R = 0.78; mean difference, -4.6% +/- 12.7% tomographic infarct size points); and new myocardial, 2 mm (R = 0.71; mean difference, 2.1% +/- 14.1% tomographic infarct size points). The best agreement (R = 0.88) between electron beam computed tomography infarct size and sestamibi single-photon emission computed tomography infarct size was achieved with regional ejection fraction and the new myocardial centroid algorithm. CONCLUSIONS: In asymmetrically contracting left ventricles, the new myocardial centroid algorithm is superior to conventional methods for tomographic analysis of regional myocardial function.

Algorithms↗
PubMed2000

Management of coronary risk factors by registered nurses versus usual care in patients with unstable angina pectoris (a chest pain evaluation in the emergency room [CHEER] substudy).

This study examined whether nurses could manage coronary risk factors in patients with unstable angina more effectively than physicians practicing usual care. Three hundred twenty-six patients were randomized in the emergency room to a 6-month program of risk factor management by a registered nurse versus participation in usual care. The nurse intervention consisted of a 30-minute counseling visit at 6 to 10 days after the chest pain episode and a second 30-minute session 1 month later. Multiple risk factors were assessed and addressed: smoking, blood lipids, blood pressure, blood glucose, physical inactivity, weight, psychological stress, and social isolation. Compared with usual care, nurse intervention patients significantly reduced both triglycerides (-29 +/- 8 vs 5 +/- 6 mg/dl; p <0.0004) and weight (-0.9 +/- 3.3 vs +0.1 +/- 2.1 kg; p = 0.0071), and had corresponding improvements in self-reported diet compliance and exercise (+34 +/- 106 vs +9 +/- 98 minutes, p = 0.0491). No significant differences between groups were observed in terms of 6-month changes in total, high-density lipoprotein, or low-density lipoprotein cholesterol, blood pressure, fasting blood glucose, percent body fat or waist-hip ratio, or psychological distress scores. The 6-month rate of recurrent events (cardiac death, out-of-hospital cardiac arrest, myocardial infarction) and/or revascularizations (coronary artery bypass surgery or coronary angioplasty) was lower in the nurse intervention group (1% vs 9%; p = 0.002). We conclude that a nurse-delivered risk factor intervention program for patients with chest pain is feasible and more effective than usual care in terms of fostering lifestyle changes that may lower coronary risk.

Aged↗
PubMed2000

Molecular-clinical spectrum of the ATR-X syndrome.

Since the identification of the ATRX gene (synonyms XNP, XH2) in 1995, it has been shown to be the disease gene for numerous forms of syndromal X-linked mental retardation [X-linked alpha thalassemia/mental retardation (ATR-X) syndrome, Carpenter syndrome, Juberg-Marsidi syndrome, Smith-Fineman-Myers syndrome, X-linked mental retardation with spastic paraplegia]. An attempt is made in this article to review the clinical spectrum associated with ATRX mutations and to analyse the evidence for any genotype/phenotype correlation.

Abnormalities, Multiple↗
PubMed2000

The effect of collateral flow and myocardial viability on the distribution of technetium-99m sestamibi in a closed-chest model of coronary occlusion and reperfusion.

Myocardial uptake of technetium-99m sestamibi at low coronary flow rates overestimates blood flow, but the relative impact of flow and viability on 99mTc-sestamibi kinetics is unclear. The objective of this study was to determine the effect of myocardial viability and the degree of collateral blood flow on the uptake and retention of 99mTc-sestamibi by examining three animal models of coronary occlusion and reperfusion, each reflecting a different state of viability and collateral blood flow. Three closed-chest animal models were studied: canine (high collateral flow, preserved viability), porcine (low collateral flow, absent viability) and porcine with slowly occlusive coronary stents producing infarction and enhanced collateral blood flow (high collateral flow, absent viability). There were seven dogs, seven pigs and six pigs, respectively, in each animal model. Animals from all three models were subjected to a 40-min total left anterior descending artery (LAD) occlusion followed by 2 h of reperfusion. 99mTc-sestamibi and radiolabelled microspheres were injected during LAD occlusion 10 min prior to reperfusion. Animals were sacrificed after 2 h of reperfusion flow. Ex situ heart slice imaging to determine risk area was followed by viability staining to determine infarct size. Slices were subsequently sectioned into equally sized radial segments and placed in a gamma well counter. Risk area as determined by ex situ 99mTc-sestamibi imaging was not significantly different by model. Pathological infarct size differed significantly by model [canine = 1%+/-1% of the left ventricle (LV); porcine = 13%+/-8% LV; porcine with stent = 14%+/-7% LV; P = 0.002)]. Collateral blood flow by microspheres during occlusion tended to differ among models (overall P = 0.08), with the canine and porcine with stent models having relatively high flow rates compared with the acute porcine model. 99mTc-sestamibi activity correlated with microsphere blood flow in all three models, with r values for individual animals (n = 20) ranging from 0.86 to 0.96 (all P<0.0001). There was a significant difference in the regression line intercepts (P<0.0001) and slopes (P<0.01) among the three models comparing 99mTc-sestamibi uptake with myocardial blood flow. 99mTc-sestamibi uptake overestimated blood flow to a greater extent in the canine model (high flow with viability) than in the porcine model (low flow, absent viability). Despite enhanced collateral flow, there was significantly less overestimation of flow in the porcine stent model (high flow, absent viability). In conclusion, at low flow rates 99mTc-sestamibi activity overestimates myocardial blood flow. This effect is most pronounced in myocardium with significant collateral flow and preserved viability, consistent with over-extraction or redistribution of the tracer. The effect is markedly decreased in non-viable myocardium regardless of blood flow.

Animals↗