Biomedical subjects

Stephen Fremes

Publications and source records attributed to Stephen Fremes.

3 recordsLinked to original sources

PubMed2006

Non ST segment elevation acute coronary syndromes: A simplified risk-orientated algorithm.

Non-ST segment elevation acute coronary syndromes (NSTE ACS) include a clinical spectrum that ranges from unstable angina to NSTE myocardial infarction. Management goals aim to prevent recurrent ACS and improve long-term outcomes by choosing a treatment strategy according to an estimate of the risk of an adverse outcome. Recent registry data suggest that patients with NSTE ACS frequently do not receive recommended treatment, and that risk stratification is not used to determine either the choice of treatment or the speed of access to coronary angiography. The present article evaluates the evidence for recommended treatment using information from recent trials and guidelines published by the major cardiac organizations in Europe and North America. Using this information, a multidisciplinary group developed a simplified algorithm that uses risk stratification to select an optimal early management strategy. Long-term outcomes are improved by a multi-faceted vascular protection strategy that is initiated at the time of hospitalization for NSTE ACS.

Acute Disease↗

PubMed2003

Impact of preoperative renal dysfunction on cardiac surgery results.

Results of cardiac surgery were analyzed using a database that included plasma creatinine levels in 2,214 patients, of whom 507 had preoperative renal dysfunction (creatinine clearance < 0.9 mL x s(-1) x m(-2)). Logistic regression and propensity score analyses found preoperative renal dysfunction to be an independent predictor of morbidity and mortality. Plotting preoperative creatinine clearance against morbidity and mortality revealed an exponential increase in morbidity and mortality when preoperative creatinine clearance was < 0.84 mL x s(-1) x m(-2). Patients were stratified for age, operative procedure, and comorbidity. In all stratified groups, preoperative creatinine clearance < 0.84 mL x s(-1) x m(-2) was associated with similar exponential increases in morbidity and mortality. In patients with preoperative renal dysfunction, elevated plasma creatinine levels persevered for 6 months postoperatively. Dialysis beyond postoperative day 10 was required in < 2% of patients with preoperative plasma creatinine of 160-200 micro mol x L(-1) and in 5% in those with creatinine > 200 micro mol x L(-1) (p < 0.05). Actuarial survival was significantly reduced (< 90% at 18 months postoperatively) in patients with preoperative renal dysfunction.

Aged↗

PubMed2002

A numerical study of blood flow in coronary artery bypass graft side-to-side anastomoses.

PURPOSE: When sequential grafts are used in multivessel coronary artery bypass grafting, the graft first supplies blood to one or more coronary arteries via a side-to-side anastomosis. We studied hemodynamics in idealized models of "parallel" and "diamond" side-to-side anastomoses, identifying features that might promote restenosis. METHODS: Blood flow was computed in three representative anastomosis configurations: parallel side-to-side, diamond side-to-side, and end-to-side. We compared configurations and the effect of host-graft diameter ratio. RESULTS: Hemodynamic patterns depended strongly on anastomosis geometry and graft/host diameter ratio. In the distal graft, the diamond configuration had large areas of low wall shear stress (WSS) and high spatial WSS gradients. In the proximal graft the unfavorable WSS patterns were comparable for all models, while the distal portion of the host artery the diamond model was best. Models with smaller host arteries had smaller regions of low WSS. CONCLUSIONS: The parallel configuration was preferred over the diamond for maintaining graft patency, while the diamond configuration appeared best for maintaining host artery patency. Since graft patency is critical, parallel configurations seem hemodynamically advantageous. Larger graft/host ratios have better hemodynamic performance than smaller ones.

Anastomosis, Surgical↗