Biomedical subjects

George Katsimaglis

Publications and source records attributed to George Katsimaglis.

7 recordsLinked to original sources

PubMed2005

Statins decrease perioperative cardiac complications in patients undergoing noncardiac vascular surgery: the Statins for Risk Reduction in Surgery (StaRRS) study.

OBJECTIVES: We sought to assess whether statins may decrease cardiac complications in patients undergoing noncardiac vascular surgery. BACKGROUND: Cardiovascular complications account for considerable morbidity in patients undergoing noncardiac surgery. Statins decrease cardiac morbidity and mortality in patients with coronary disease, and the beneficial treatment effect is seen early, before any measurable increase in coronary artery diameter. METHODS: A retrospective study recorded patient characteristics, past medical history, and admission medications on all patients undergoing carotid endarterectomy, aortic surgery, or lower extremity revascularization over a two-year period (January 1999 to December 2000) at a tertiary referral center. Recorded perioperative complication outcomes included death, myocardial infarction, ischemia, congestive heart failure, and ventricular tachyarrhythmias occurring during the index hospitalization. Univariate and multivariate logistic regressions identified predictors of perioperative cardiac complications and medications that might confer a protective effect. RESULTS: Complications occurred in 157 of 1,163 eligible hospitalizations and were significantly fewer in patients receiving statins (9.9%) than in those not receiving statins (16.5%, p = 0.001). The difference was mostly accounted by myocardial ischemia and congestive heart failure. After adjusting for other significant predictors of perioperative complications (age, gender, type of surgery, emergent surgery, left ventricular dysfunction, and diabetes mellitus), statins still conferred a highly significant protective effect (odds ratio 0.52, p = 0.001). The protective effect was similar across diverse patient subgroups and persisted after accounting for the likelihood of patients to have hypercholesterolemia by considering their propensity to use statins. CONCLUSIONS: Use of statins was highly protective against perioperative cardiac complications in patients undergoing vascular surgery in this retrospective study.

Acute Disease↗

PubMed2005

Correction for heart rate variability improves coronary magnetic resonance angiography.

PURPOSE: To address degradation of coronary MR angiography (MRA) image quality due to heart rate variability (HRV)-associated variations in coronary artery position and motion. MATERIALS AND METHODS: Free-breathing navigator-gated and -corrected coronary MRA using subject-specific trigger delays and acquisition windows was combined with a real-time HRV correction algorithm, such as commonly used in left ventricular wall motion studies. Ten healthy adults underwent free-breathing navigator-gated and -corrected coronary MRA with and without HRV correction. Signal-to-noise (SNR), contrast-to-noise (CNR), vessel length, diameter, sharpness, and subjective image quality (on a five-point scale) were compared in a blinded fashion. RESULTS: Vessel sharpness improved significantly for both the left (LCA) and right (RCA) coronary artery systems (P = 0.016 and P = 0.015, respectively) with the use of HRV correction. Subjective image quality also improved significantly when HRV correction was used (P = 0.003). There were no significant differences with regard to SNR and CNR (P > 0.1). CONCLUSIONS: Preliminary results suggest that HRV correction improves objective and subjective image quality in coronary MRA. Continued studies in patients with known or suspected coronary artery disease are warranted to investigate the clinical impact of this technique.

Adolescent↗

PubMed2005

Effect of raloxifene on aortic elasticity in healthy postmenopausal women.

BACKGROUND: The effect of raloxifene on aortic elasticity in healthy postmenopausal women is unknown. The purpose of the present study was to examine the effect of raloxifene on aortic elasticity and cardiovascular structure and function in healthy postmenopausal women. METHODS: A randomized, crossover, double-blind, placebo-controlled clinical trial was performed. Fourteen healthy postmenopausal women received treatment with raloxifene 60 mg daily and matching placebo for 8 weeks with an 8-week washout period in between the 2 treatment periods. Cardiovascular magnetic resonance imaging was used to assess ascending thoracic and abdominal aortic elasticity and cardiovascular structure and function (left ventricular volumes, ejection fraction, and mass and mitral annular displacement) before and at the end of each treatment period. RESULTS: Administration of raloxifene had no significant effect on either heart rate or systemic blood pressure. Raloxifene treatment was associated with a small decrease of the ascending aorta wall thickness (pretreatment 2.4 +/- 0.3 vs posttreatment 2.2 +/- 0.2 mm, P = .01). Consequently, there was an increase in the Young's elastic modulus after raloxifene treatment at the ascending thoracic aorta but not the abdominal aorta. There were no significant differences in aortic compliance or any cardiac indexes after raloxifene treatment. CONCLUSIONS: Raloxifene administration in healthy postmenopausal women over an 8-week period may decrease the aortic wall thickness but has no significant effects on aortic compliance or cardiac structure and function.

Aorta↗

PubMed2004

In vivo magnetic resonance imaging of coronary thrombosis using a fibrin-binding molecular magnetic resonance contrast agent.

BACKGROUND: The advent of fibrin-binding molecular magnetic resonance (MR) contrast agents and advances in coronary MRI techniques offers the potential for direct imaging of coronary thrombosis. We tested the feasibility of this approach using a gadolinium (Gd)-based fibrin-binding contrast agent, EP-2104R (EPIX Medical Inc), in a swine model of coronary thrombus and in-stent thrombosis. METHODS AND RESULTS: Ex vivo and in vivo sensitivity of coronary MR thrombus imaging was tested by use of intracoronarily delivered Gd-DTPA-labeled fibrinogen thrombi (n=6). After successful demonstration, in-stent coronary thrombosis was induced by x-ray-guided placement of thrombogenic-coated, MR-lucent stents (n=5). After stent placement, 60 micromol of EP-2104R was injected via the left main coronary artery. Free-breathing, navigator-gated 3D coronary MR angiography and thrombus imaging were performed (1) before and after stent placement and (2) before and after EP-2104R. Thrombi were confirmed by x-ray angiography and autopsy. Fibrinogen thrombi: 5 of 6 intracoronarily delivered Gd-labeled fibrinogen clots (approximately 250 micromol/L Gd) were visible on MRI and subsequently confirmed by x-ray angiography. In-stent thrombi: in-stent thrombosis was observed in all stents after EP-2104R. Four of 5 thrombi were confirmed by x-ray angiography. Chemical analysis of 2 thrombi demonstrated 99 to 147 micromol/L Gd. CONCLUSIONS: We demonstrate the feasibility of MRI of coronary thrombus and in-stent thrombosis using a novel fibrin-binding molecular MR contrast agent. Potential applications include detection of coronary in-stent thrombosis or thrombus burden in patients with acute coronary syndromes.

Animals↗

PubMed2004

Assessment of left atrial volume by contrast enhanced magnetic resonance angiography.

Left atrial (LA) volume is associated with cardiovascular morbidity, particularly atrial fibrillation. Contrast-enhanced magnetic resonance angiography (CE-MRA) visualizes the LA, but the validity of LA volume measurements using this technique has not been evaluated. We performed CE-MRA and cine magnetic resonance (MR) in 18 consecutive patients referred for CE-MRA prior to atrial fibrillation ablation. The CE-MRA LA volumes were compared to cine MR LA volumes at the maximal LA size and at LA end-diastole using linear regression and limits of agreement analysis. The mean cine MR LA volume was 118 +/- 39 mL at maximal LA size and 91 +/- 38 mL at LA end-diastole. Left atrial volume determined by CE-MRA was 93 +/- 38 mL. Although the CE-MRA LA volume had a strong correlation with the maximal cine MR LA volume (R2 = 0.86, p < 0.001), the 95% limits of agreement were relatively wide (-54 to 3 mL). The cine MR LA end-diastolic and CE-MRA LA volumes were more closely correlated (R2 = 0.98, p < 0.001) with narrow 95% limits of agreement (-8 to 11 mL). The CE-MRA LA volumes correspond most closely to LA end-diastolic cine MR LA volumes and may be a useful measure of LA size.

Cardiac Volume↗

PubMed2004

A method for the determination of proximal pulmonary vein size using contrast-enhanced magnetic resonance angiography.

OBJECTIVES: We sought to develop a reproducible method for characterizing the anatomy of the proximal pulmonary veins. BACKGROUND: Contrast-enhanced three-dimensional magnetic resonance angiography (CE-MRA) is a commonly requested test before and after radiofrequency ablation for the treatment of atrial fibrillation. While CE-MRA readily visualizes the pulmonary veins, there is no standardized method for determining their size and cross-sectional anatomy. METHODS: Data for 24 consecutive patients referred for pulmonary vein CE-MRA before an elective ablation procedure for the treatment of atrial fibrillation were analyzed. Detailed measurements of the pulmonary vein diameter, circumference, and cross-sectional area were obtained at three locations: the juncture of the pulmonary vein with the left atrium (LA) (position 1J), the narrowest segment within 5 mm of the juncture (position 2(5mm)), and at the location in the sagittal plane at which the pulmonary veins separate from the LA and from each other (position 3Sag). Intraobserver and interobserver variabilities were also determined for each method. RESULTS: The left lower pulmonary vein was significantly smaller than the other pulmonary veins at positions 1J and 2(5mm) (p<0.05). The right upper pulmonary vein was significantly larger than the other pulmonary vein at position 3Sag (p<0.05). At positions 1J and 2(5mm), the diameter had a low correlation with the circumference and cross-sectional area. At position 3Sag, the major and minor axis dimensions had a very high correlation with the circumference and cross-sectional area. The intraobserver and interobserver variabilities were substantially lower (better) for position 3Sag. CONCLUSIONS: Pulmonary vein diameter measurements are highly variable and do not reflect true anatomic variation in cross-sectional anatomy. A sagittal method of determining pulmonary vein size was highly reproducible and may therefore be advantageous for use in patients likely to need serial examinations.

Adult↗

PubMed2003

Coronary magnetic resonance angiography.

Coronary magnetic resonance angiography (CMRA) is a technique in clinical evolution. Current clinical applications include assessment for coronary anomalies, aneurysms, bypass graft patency, and, in experienced centers, the exclusion of proximal and multivessel coronary artery disease (CAD). As local expertise increases and more extensive multicenter data become available, additional applications will be established. CMRA promises to supplement and in some cases obviate the need for X-ray contrast angiography, and to expand our understanding of the pathophysiology of CAD.

Coronary Aneurysm↗