Biomedical subjects
Raymond J Gibbons
Publications and source records attributed to Raymond J Gibbons.
Noninvasive risk stratification after myocardial infarction: new evidence, new questions.
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Impact of time to therapy and reperfusion modality on the efficacy of adenosine in acute myocardial infarction: the AMISTAD-2 trial.
AIMS: The purpose of this analysis was to determine whether the efficacy of adenosine vs. placebo was dependent on the timing of reperfusion therapy in the second Acute Myocardial Infarction Study of Adenosine (AMISTAD-II). METHODS AND RESULTS: Patients presenting with ST-segment elevation anterior AMI were randomized to receive placebo vs. adenosine (50 or 70 microg/kg/min) for 3 h starting within 15 min of reperfusion therapy. In the present post hoc hypothesis generating study, the results were stratified according to the timing of reperfusion, i.e. > or = or < the median 3.17 h, and by reperfusion modality. In patients receiving reperfusion < 3.17 h, adenosine compared with placebo significantly reduced 1-month mortality (5.2 vs. 9.2%, respectively, P = 0.014), 6-month mortality (7.3 vs. 11.2%, P = 0.033), and the occurrence of the primary 6-month composite clinical endpoint of death, in-hospital CHF, or rehospitalization for CHF at 6 months (12.0 vs. 17.2%, P = 0.022). Patients reperfused beyond 3 h did not benefit from adenosine. CONCLUSION: In this post hoc analysis, 3 h adenosine infusion administered as an adjunct to reperfusion therapy within the first 3.17 h onset of evolving anterior ST-segment elevation AMI enhanced early and late survival, and reduced the composite clinical endpoint of death or CHF at 6 months.
Effect of blinded peer review on abstract acceptance.
CONTEXT: Peer review should evaluate the merit and quality of abstracts but may be biased by geographic location or institutional prestige. The effectiveness of blinded peer review at reducing bias is unknown. OBJECTIVE: To evaluate the effect of blinded review on the association between abstract characteristics and likelihood of abstract acceptance at a national research meeting. DESIGN AND SETTING: All abstracts submitted to the American Heart Association's annual Scientific Sessions research meeting from 2000-2004. Abstract review included the author's name and institution (open review) from 2000-2001, and this information was concealed (blinded review) from 2002-2004. Abstracts were categorized by country, primary language, institution prestige, author sex, and government and industry status. MAIN OUTCOME MEASURE: Likelihood of abstract acceptance during open and blinded review, by abstract characteristics. RESULTS: The mean number of abstracts submitted each year for evaluation was 13,455 and 28.5% were accepted. During open review, 40.8% of US and 22.6% of non-US abstracts were accepted (relative risk [RR], 1.81; 95% confidence interval [CI], 1.75-1.88), whereas during blinded review, 33.4% of US and 23.7% of non-US abstracts were accepted (RR, 1.41; 95% CI, 1.37-1.45; P<.001 for comparison between peer review periods). Among non-US abstracts, during open review, 31.1% from English- speaking countries and 20.9% from non-English-speaking countries were accepted (RR, 1.49; 95% CI, 1.39-1.59), whereas during blinded review, 28.8% and 22.8% of abstracts were accepted, respectively (RR, 1.26; 95% CI, 1.19-1.34; P<.001). Among abstracts from US academic institutions, during open review, 51.3% from highly prestigious and 32.6% from nonprestigious institutions were accepted (RR, 1.57; 95% CI, 1.48-1.67), whereas during blinded review, 38.8% and 29.0% of abstracts were accepted, respectively (RR, 1.34; 95% CI, 1.26-1.41; P<.001). CONCLUSIONS: This study provides evidence of bias in the open review of abstracts, favoring authors from the United States, English-speaking countries outside the United States, and prestigious academic institutions. Moreover, blinded review at least partially reduced reviewer bias.
ACC/AHA 2005 guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic): executive summary a collaborative report from the American Association for Vascular Surgery/Society for Vascular Surgery, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Peripheral Arterial Disease) endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation; National Heart, Lung, and Blood Institute; Society for Vascular Nursing; TransAtlantic Inter-Society Consensus; and Vascular Disease Foundation.
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ACC/AHA 2005 Practice Guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic): a collaborative report from the American Association for Vascular Surgery/Society for Vascular Surgery, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Peripheral Arterial Disease): endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation; National Heart, Lung, and Blood Institute; Society for Vascular Nursing; TransAtlantic Inter-Society Consensus; and Vascular Disease Foundation.
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Therapy for patients with acute coronary syndromes--new opportunities.
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The utilization of cardiac imaging.
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Revascularization in systolic heart failure: a difficult decision.
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Prognostic utility of single-photon emission computed tomography in adult patients with hypertrophic cardiomyopathy.
BACKGROUND: Data derived from stress myocardial perfusion imaging (MPI) carry prognostic significance in young patients with hypertrophic cardiomyopathy (HCM), but there are limited data on the utility of stress MPI in patients with HCM who are older. This study examined the prognostic significance of stress MPI in an adult population of patients with HCM. METHODS: We examined 158 patients with HCM (aged 60 +/- 16 years, 61% men) who underwent exercise or pharmacologic stress MPI. Summed stress score (SSS, normal = 56) and summed reversibility scores were calculated for each patient. Follow-up was complete in 157 (99%) patients at a median duration of 5.2 years. RESULTS: Normal single-photon emission computed tomography (SPECT) images were present in 38% of the population. Summed stress score (P = .01) and summed reversibility score (P = .03) were both significantly associated with cardiovascular death. Survival at 10 years was significantly better in those with normal versus abnormal SPECT (89% vs 67%, P = .04). Ten-year survival also was better in those without versus those with ischemia (90% vs 64%, P = .02). Five-year survival could be stratified by SSS risk categories: low risk (SSS > or = 53), 97%; intermediate risk (SSS = 48-52), 94%; and high risk (SSS < or = 47), 79% (P = .04). Bivariate models of SSS and other significant covariates supported an independent relation of SSS to cardiovascular death. CONCLUSIONS: In an older population of patients with HCM referred for SPECT imaging, abnormal stress MPI identifies those at increased risk of cardiovascular death.
The value of stress single photon emission computed tomography in patients without known coronary artery disease presenting with dyspnea.
BACKGROUND: Dyspnea is a complex system with multiple etiologies, including myocardial ischemia ("anginal equivalent"). Few studies have examined the utility of stress testing to detect coronary artery disease in this setting. The purpose of this study was to examine the prevalence, severity, and prognostic value of perfusion defects detected by stress single photon emission computed tomography (SPECT) imaging in patients with dyspnea. METHODS: SPECT imaging was performed in 1864 patients (age 65.8 +/- 10.2 years, 52% male, 23% diabetic, 89% overweight/obese) without known coronary artery disease referred for evaluation of dyspnea. Dyspnea was rated mild, moderate, or severe. SPECT scans were categorized low, intermediate, or high risk. The associations of stress SPECT imaging results with clinical variables and mortality were analyzed. RESULTS: An abnormal perfusion SPECT image was present in 45% of patients and a high-risk scan in 11%. Male sex, diabetes, and clinical severity of dyspnea were the strongest predictors of both an abnormal and high-risk SPECT scan. A high-risk scan was present in 5% of nondiabetic women with mild dyspnea versus 22% of diabetic men with dyspnea of any severity. At 10 years, survival by SPECT scan category was low risk 75%, intermediate risk 68%, and high risk 53% (P < .001). CONCLUSIONS: In this population of older overweight patients referred for evaluation of dyspnea, there was a high prevalence of abnormal (45%) and high-risk (11%) SPECT scans. High-risk scans were associated with much worse 10-year survival.
Asymptomatic patients with diabetes mellitus should not be screened for coronary artery disease.
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Differences in left ventricular ejection fraction and volumes measured at rest and poststress by gated sestamibi SPECT.
BACKGROUND: Some studies suggested that the poststress left ventricle ejection fraction (LV EF) is lower than rest LV EF in patients with stress-induced ischemia. METHODS AND RESULTS: By using a 2-day protocol and 30 mCi Tc-99m sestamibi, LV EF, end-systolic volume (ESV), and end-diastolic volume (EDV) were measured with gated SPECT. Of 99 eligible patients, 91 had technically adequate studies. Poststress LV EF minus rest LV EF was defined as DeltaLV EF. DeltaEDV and DeltaESV were similarly defined. Rest and poststress LV EF (r = 0.89), EDV (r = 0.78), and ESV (r = 0.93) were highly correlated (P <.001). Rest LV EF, EDV, and ESV were not significantly different between patients with and without stress-induced ischemia. DeltaLV EF was significantly lower in patients with stress-induced ischemia (-3.5% +/- 4.5% vs -1.1% +/- 4.7%, P = .02). Mean LV EF poststress in ischemic patients was 55.0% +/- 10.5% vs 61.2% +/- 10.0% in nonischemic patients (P = .008). However, only 1 patient (3%) with ischemia had DeltaLV EF that exceeded the 95% confidence limit of DeltaLV EF for normal patients. Ischemia was significantly associated with increased DeltaEDV and DeltaESV (P < .01). CONCLUSIONS: Stress-induced ischemia is associated with poststress reduction in LV EF and increased poststress EDV and ESV. However, the effect of ischemia on the difference between poststress and rest EF measurements is modest and rarely exceeds the confidence limits in normal patients undergoing 2-day protocols. In most patients, poststress LV EF is an accurate reflection of rest LV EF.
ACC/AHA Guidelines for the Management of Patients with Peripheral Arterial Disease (lower extremity, renal, mesenteric, and abdominal aortic): a collaborative report from the American Associations for Vascular Surgery/Society for Vascular Surgery, Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (writing committee to develop guidelines for the management of patients with peripheral arterial disease)--summary of recommendations.
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Pathophysiological characteristics of heart rate recovery in heart failure.
PURPOSE: Heart failure (HF) is associated with blunted HR recovery after exercise. The determinants of altered HR recovery in HF are unknown. The aim of this study was to investigate clinical correlates of HR recovery in HF patients. METHODS: Echocardiography, pulmonary function tests, exercise testing, and neurohormonal measurements were performed in 98 HF patients. HR recovery was calculated as the difference between heart rate at peak exercise and at 1 min into a recovery period. Study subjects were divided into three groups based on HR recovery tertiles: group 1 (HR recovery < or = 6 bpm), group 2 (7 < or = HR recovery < or = 12), and group 3 (HR recovery > or = 13). RESULTS: There were significant differences between the groups in multiple parameters. Compared with group 3, patients in group 1 had greater E/A ratios (1.81 +/- 0.26 vs 0.98 +/- 0.12, P = 0.011), shorter deceleration time (170 +/- 11 vs 223 +/- 11 ms, P = 0.016), and higher plasma atrial natriuretic peptide levels (207 +/- 32 vs 101 +/- 12 pg.mL, P = 0.008), indicating higher left ventricular filling pressures and elevated left atrial pressures. Pulmonary function tests were suggestive of greater restrictive changes in the lungs. Finally, subjects in group 1 had impaired exercise capacity, as evidenced by shorter exercise duration (5.2 +/- 0.2 vs 8.3 +/- 0.4 min, P < 0.001), lower peak VO2 (14.6 +/- 0.6 vs 22.2 +/- 1.0 mL.kg(-1).min(-1), P < 0.001), higher VE/VCO2 ratios (36.4 +/- 1.1 vs 31.1 +/- 0.9, P = 0.001), and reduced chronotropic responses to exercise (39 +/- 3 vs 69 +/- 4 bpm, P < 0.001). CONCLUSION: HR recovery may be a clinically useful index identifying HF patients with distinct echocardiographic, neurohormonal, and hemodynamic characteristics. This may have implications for our understanding of the pathophysiology of impaired HR recovery in HF as well as for the clinical evaluation of such patients.
Reproducibility of measurements of regional myocardial blood flow in a model of coronary artery disease: Comparison of H215O and 13NH3 PET techniques.
UNLABELLED: PET absolute myocardial blood flow (MBF) with H(2)15O and 13NH3 are widely used in clinical and research settings. However, their reproducibility with a 16-myocardial segment model has not been examined in chronic coronary artery disease (CAD). We examined the short-term reproducibility of PET H(2)15O MBF and PET 13NH3 MBF in an animal model of chronic CAD. METHODS: Twelve swine (mean weight +/- SD, 38 +/- 5 kg) underwent percutaneous placement of a copper stent in the mid circumflex coronary artery, resulting in an intense inflammatory fibrotic reaction with luminal stenosis at 4 wk. Each animal underwent repeated resting MBF measurements by PET H(2)15O and PET 13NH3. Attenuation-corrected images were analyzed using commercial software to yield absolute MBF (mL/min/g) in 16 myocardial segments. MBF was also normalized to the rate.pressure product (RPP). RESULTS: By Bland-Altman reproducibility plots, the mean difference was 0.01 +/- 0.18 mL/min/g and 0.01 +/- 0.11 mL/min/g, with confidence limits of +/-0.36 and +/-0.22 mL/min/g for uncorrected regional PET H(2)15O MBF and for uncorrected regional PET 13NH3 MBF, respectively. The repeatability coefficient ranged from 0.09 to 0.43 mL/min/g for H(2)15O and from 0.09 to 0.18 mL/min/g for 13NH3 regional MBF. RPP correction did not improve reproducibility for either PET H(2)15O or PET 13NH3 MBF. The mean difference in PET H(2)15O MBF was 0.03 +/- 0.14 mL/min/g and 0.02 +/- 0.19 mL/min/g for infarcted and remote regions, respectively, and in PET 13NH3 MBF was 0.03 +/- 0.11 mL/min/g and 0.00 +/- 0.09 mL/min/g for infarcted and remote regions, respectively. CONCLUSION: PET H(2)15O and PET 13NH3 resting MBF showed excellent reproducibility in a closed-chest animal model of chronic CAD. Resting PET 13NH3 MBF was more reproducible than resting PET H(2)15O MBF. A high level of reproducibility was maintained in areas of lower flow with infarction for both isotopes.
ACCF/ASNC appropriateness criteria for single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI): a report of the American College of Cardiology Foundation Quality Strategic Directions Committee Appropriateness Criteria Working Group and the American Society of Nuclear Cardiology endorsed by the American Heart Association.
Under the auspices of the American College of Cardiology Foundation (ACCF) and the American Society of Nuclear Cardiology (ASNC), an appropriateness review was conducted for radionuclide cardiovascular imaging (RNI), specifically gated single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI). The review assessed the risks and benefits of the imaging test for several indications or clinical scenarios and scored them based on a scale of 1 to 9, where the upper range (7 to 9) implies that the test is generally acceptable and is a reasonable approach, and the lower range (1 to 3) implies that the test is generally not acceptable and is not a reasonable approach. The mid range (4 to 6) implies that the test may be generally acceptable and may be a reasonable approach for the indication. The indications for this review were primarily drawn from existing clinical practice guidelines and modified based on discussion by the ACCF Appropriateness Criteria Working Group and the Technical Panel members who rated the indications. The method for this review was based on the RAND/UCLA approach for evaluating appropriateness, which blends scientific evidence and practice experience. A modified Delphi technique was used to obtain first- and second-round ratings of 52 clinical indications. The ratings were done by a Technical Panel with diverse membership, including nuclear cardiologists, referring physicians (including an echocardiographer), health services researchers, and a payer (chief medical officer). These results are expected to have a significant impact on physician decision making and performance, reimbursement policy, and future research directions. Periodic assessment and updating of criteria will be undertaken as needed.
Improved survival in asymptomatic diabetic patients with high-risk SPECT imaging treated with coronary artery bypass grafting.
BACKGROUND: The Bypass Angioplasty Revascularization Investigation trial demonstrated that symptomatic diabetics with multivessel coronary artery disease had a survival advantage with initial coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI). No published study has examined different treatments and outcome in asymptomatic diabetics. METHODS AND RESULTS: This study group consisted of 826 asymptomatic diabetics (age 62+/-12 years; 76% men) without known coronary artery disease who had abnormal myocardial perfusion during stress single photon emission computed tomography (SPECT). SPECT images were classified as low-, intermediate-, and high-risk. Early revascularization (CABG or PCI < or =4 months after SPECT) was performed in 76 patients. Survival (follow-up, 5.3+/-3.3 years) was compared in patients treated with CABG, PCI, or medical therapy. Revascularization (CABG or PCI) was performed in 54 of 261 patients with high-risk scans and was independently associated with improved survival (chi2=4.55; P=0.03 after multivariate adjustment). Subset analysis demonstrated that the survival advantage was confined to patients treated with CABG (n=39), with a 5-year survival CABG at 85%, PCI at 72%, and medical therapy at 67% (P=0.02 for 3 groups). Although CABG was associated with better survival, mortality remained high (3% per year). There was no survival advantage by treatment for patients with less-severe SPECT abnormalities. CONCLUSIONS: These nonrandomized data suggest that CABG improves survival in asymptomatic diabetic patients with high-risk SPECT, although revascularization was performed infrequently in these patients. These results parallel those of the Bypass Angioplasty Revascularization Investigation trial in symptomatic diabetic patients.