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Biomedical subjects

Robert E Safford

Publications and source records attributed to Robert E Safford.

9 recordsLinked to original sources
PubMed2006

Computed tomographic angiography of the coronary arteries: techniques and applications.

Computed tomographic coronary angiography (CT-CA) is a direct but minimally invasive method of visualizing coronary arteries. Multidetector-row computed tomography (MDCT) is currently the CT modality most commonly used for coronary artery imaging. MDCT has been successfully used to detect stenoses in coronary arteries and coronary artery bypass grafts and to assess congenital coronary anomalies. Patients should not undergo CT-CA with MDCT if they have an irregular heart rhythm, a heart rate greater than 70 beats/min, and contraindications to pharmacologic agents for heart rate control, or if they have severe coronary artery disease or are likely to require revascularization.

Coronary Angiography↗
PubMed2005

Clinical factors associated with abandonment of a rate-control or a rhythm-control strategy for the management of atrial fibrillation in the AFFIRM study.

OBJECTIVE: The objective of the current study was to determine the clinical factors that were associated with abandonment of a rate-control or a rhythm-control strategy in patients with atrial fibrillation (AF). BACKGROUND: Although the AFFIRM Study demonstrated that outcomes are similar with a primary strategy of rate-control or rhythm-control for AF, there may be clinical or demographic factors associated with abandonment of the initial treatment strategy. Knowledge of these risk factors would be useful so that patients may be given appropriate initial therapy and, as appropriate, switched to alternative treatments earlier. METHODS: Patients in the AFFIRM Study were subdivided into those who were maintained on their initial treatment strategy versus those who abandoned initial treatment strategy for alternative therapies. We determined the clinical and demographic factors associated with change in initial treatment strategy. RESULTS: At 5 years the original treatment strategy was maintained in 85% of the patients in the rate-control arm versus 62% of those in the rhythm-control arm (P <.0001). Length of the qualifying episode of AF was associated with abandonment of both rhythm-control and rate-control strategies. Antiarrhythmic drug failure before randomization and a history of thyroid disease also were associated with abandonment of rhythm-control. Patients were more likely to maintain rate-control if they already had an implanted pacemaker or if they were older than 75 years, while an ejection fraction <30% was associated with abandonment of the rate-control strategy. CONCLUSIONS: In patients with AF, rhythm-control strategies are abandoned significantly more often than rate-control strategies. Patients with long durations of AF on presentation or previous antiarrhythmic drug failure might be considered for rate-control as initial treatment.

Age Factors↗
PubMed2005

Factors affecting bleeding risk during anticoagulant therapy in patients with atrial fibrillation: observations from the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study.

BACKGROUND: Stroke and systemic thromboembolism are serious problems for patients with atrial fibrillation (AF), but their incidence can be substantially reduced by appropriate anticoagulation. Bleeding is the major complication of anticoagulant treatment, and the relative risks for bleeding vs stroke must be considered when starting anticoagulation. METHODS: The AFFIRM trial included patients with AF and at least one risk factor for stroke, randomly assigning them to either a rate-control or rhythm-control strategy. All patients were initially treated with warfarin. The incidence of protocol-defined major and minor bleeding was documented during follow-up. Variables associated with bleeding were determined using a Cox proportional hazards model, using baseline and time-dependent covariates. RESULTS: The 4060 patients in the AFFIRM trial were followed for an average of 3.5 years. Major bleeding occurred in 260 patients, an annual incidence of approximately 2% per year, with no significant difference between the rate-control and rhythm-control groups. Increased age, heart failure, hepatic or renal disease, diabetes, first AF episode, warfarin use, and aspirin use were significantly associated with major bleeding. Minor bleeding was common in both treatment arms, with 738 patients reporting this problem in one or more visits. CONCLUSIONS: Bleeding is a significant problem that complicates management of patients with AF. Risk factors for bleeding can be identified, and knowledge of these risk factors can be used to plan therapy.

Aged↗
PubMed2004

Imaging of congenital coronary anomalies with multislice computed tomography.

OBJECTIVE: To describe a single-center experience of using retrospectively gated multislice computed tomographic (MSCT) coronary angiography for imaging congenital coronary anomalies. PATIENTS AND METHODS: We retrospectively reviewed the clinical information and imaging studies for 9 patients diagnosed as having congenital coronary anomalies on invasive, selective coronary angiography between February 2001 and October 2003 at the Mayo Clinic in Jacksonville, Fla. Two experienced observers classified by consensus the origin and proximal course of the abnormal coronary arteries as seen on MSCT. RESULTS: In 1 patient, MSCT showed a normal but extremely anterior origin of the right coronary artery from the right aortic sinus of Valsalva. In the other 8 patients, the origin and course of 4 anomalous right coronary arteries, 2 anomalous left circumflex coronary arteries, and 2 single coronary arteries were recognized easily on MSCT. CONCLUSION: Similar to electron beam computed tomography and magnetic resonance imaging, widely available MSCT can characterize the proximal course of congenitally abnormal coronary arteries and thus aid in clinical decision making for patients with such anomalies.

Adult↗
PubMed2003

AFFIRM and RACE trials: implications for the management of atrial fibrillation.

The Atrial Fibrillation (AF) Follow-up Investigation of Rhythm Management (AFFIRM) and Rate Control versus Electrical Cardioversion for Persistent Atrial Fibrillation Study (RACE) Trials evaluated strategies of rate control or rhythm control in atrial fibrillation. AFFIRM enrolled patients with recent onset AF, and at entry over half of all patients were in sinus rhythm. At any point in the trial, the achieved difference in cardiac rhythm was likely only about 30%. In RACE all patients were entered in AF, and at the end of the study, sinus rhythm was present in 10% vs 39%. The strategy of rate control was non-inferior to the rhythm control strategy in both trials, and permits consideration of rate control as primary therapy. However, the actual differences in rhythm were relatively small, and do not allow the conclusion that maintenance of sinus rhythm is inferior to non-maintenance. Current guidelines recommend that patients with paroxysmal AF receive warfarin if they have risk factors for stroke. This is supported by data from AFFIRM. Most strokes in AFFIRM occurred either during subtherapeutic INR, or after cessation of warfarin. Since more patients in the rhythm control arm of AFFIRM discontinued warfarin, it is possible that asymptomatic recurrences of paroxysmal AF fostered clot development and embolization. We cannot answer from the data available whether or not it is safe to discontinue anticoagulation if all episodes of AF are suppressed. Among the reasons that AF is associated with increased mortality may be that it encourages development of congestive heart failure or progressive left ventricular dysfunction. Congestive heart failure occurrence was monitored in both trials, and occurred at a rate of 2-5% without significant differences between rate and rhythm arms. In patients with heart failure at entry, a mortality trend in AFFIRM favored the rhythm control arm. The issue of survivorship and rhythm control in AF in congestive heart failure is undergoing further testing.

Anticoagulants↗
PubMed2002

Current results and new developments of coronary angiography with use of contrast-enhanced computed tomography of the heart.

Electron beam computed tomography (EBCT) is the reference standard for x-ray-based tomographic imaging of the heart because of its high temporal resolution, but it is available in only a few centers. Quantification of coronary calcium is the most widely recognized use of EBCT for cardiac imaging. This technique requires no contrast media and provides an accurate assessment of overall plaque burden in the coronary tree; however, it does not directly identify or localize coronary stenoses. Multislice spiral (helical) CT (MSCT) is a new technology that provides images of the beating heart in diagnostic quality under many circumstances and may facilitate the broader application of cardiac and coronary CT. Currently, for imaging of the heart, much more experience exists with EBCT than with MSCT. Contrast-enhanced CT coronary angiography (CTCA) can be done with EBCT or MSCT to obtain images of the major branches of the coronary tree and to define luminal narrowing. Studies at experienced centers performed with small numbers of patients show that sensitivity, specificity, and negative predictive value are good with CTCA in the assessment of obstructive coronary artery disease, but CTCA remains an investigational technique for these applications. Computed tomographic coronary angiography can be clinically useful for assessing coronary artery bypass graft patency and congenital coronary abnormalities.

Contrast Media↗
PubMedDate not supplied

Image quality in a standardized algorithm for minimally invasive coronary angiography with multislice spiral computed tomography.

PURPOSE: To report our experience with a standardized approach to pharmacologic heart rate control and image postprocessing for computed tomographic coronary angiography (CTCA) with multislice computed tomography (MSCT). METHOD: Two experienced observers used transaxial tomograms and maximum-intensity projections to classify coronary segments (12 per patient, 135 consecutive patients) for degree of stenosis. One factor affecting image quality was identified for each segment that could not be assessed. RESULTS: Nine patients (7%) were excluded for technical reasons. Of 1,512 segments from 126 patients, 1,086 (72%) were assessable (8.6 per patient). Of 300 segments from 25 patients who also had selective coronary angiography, CTCA was able to assess 211 (70%) and detected significant disease in 27 (82% sensitivity, 96% specificity, 73% positive predictive value, and 97% negative predictive value). Vessel caliber, heart rate, and Agatston score were associated with inability to assess 426 coronary segments (28%). CONCLUSION: Heart rate and Agatston score are important predictors of the ability to assess proximal and midcoronary segments by CTCA with MSCT.

Adult↗