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J Sines

Publications and source records attributed to J Sines.

4 recordsLinked to original sources
PubMed2001

Comparison of the flow capacity of free arterial grafts and saphenous vein grafts for coronary bypass surgery.

UNLABELLED: There is controversy regarding the flow reserve and capacity of arterial conduits to meet the needs of the myocardium. This study compared flow in 22 free arterial bypasses to 15 saphenous vein grafts in procedures involving twenty patients. To assess the maximal flow possible, (flow capacity) graft flow was measured using a calibrated pump while perfusing blood cardioplegia through the conduit and distal anastomosis during cardiac arrest (no competitive flow). This assessment was subsequently confirmed with whole blood during myocardial contraction while on cardiopulmonary bypass. Twenty-two free arterial grafts were used; 15 right internal mammary artery grafts, 4 right gastroepiploic grafts, 3 inferior epigastric artery grafts, and 3 sequential bypasses. Free arterial conduit flow ranged from 50 to 180cc/ml, with an average flow of 102.5+/-28.5ml/min as compared to saphenous vein graft flow, 102+/-28 ml/min. No correlation of flow with the conduit size was found. Arterial graft flow demonstrated a mild correlation with the size of the native coronary artery bypassed (R=0.47, P</=0.02). CONCLUSIONS: Basal flow through free arterial grafts is equivalent to saphenous vein grafts and is primarily determined by the native coronary vessels. The flow reserve for free arterial conduits is more than adequate for coronary bypass surgery.

Adult↗
PubMed2001

Based on acute outcomes, "all arterial" coronary bypass surgery should be performed on younger elective patients.

OBJECTIVES: This study evaluated acute results as a function of the number of arterial conduits used to compare procedural differences and the subsequent effects on acute outcomes in selected patient populations. BACKGROUND: All arterial operations may provide better long-term results for younger patients undergoing coronary bypass surgery (CABG). However, concerns regarding additional morbidity when using multiple arterial conduits have inhibited their use. METHODS: The study comprised a retrospective review of patients (2,586) undergoing CABG. Group 1 consists of single artery vein graft (1,755). Group 2: two arteries were used in addition to vein grafts (209). Group 3: three or more arterial conduits were used, with or without vein grafts (116). Group 4: only vein grafts were used (506). RESULTS: Patients undergoing primarily arterial procedures, Group 2 and 3, were younger, had a better exercise profile, less history of myocardial infarction (MI), had less left ventricular dysfunction. There were also fewer emergencies, co-morbidities and associated procedures in this group. The cardiopulmonary bypass and cross clamp times were longer in those procedures with three or more arteries; however, this difference was only thirteen and fourteen minutes, respectively. Post-operative complications were higher in patients in the vein only group. The hospital stay and mortality was equivalent among groups in which an arterial bypass was used and better than those in which only vein grafts were used. CONCLUSIONS: For younger patients, "all arterial operations," require only minimal increases in ischemic and operative times, which do not affect acute outcomes.

Age Factors↗
PubMed1994

Electron cryomicroscopy and digital image processing of lipoprotein(a).

Electron cryomicroscopy was used to study the structure of human lipoprotein(a) (Lp(a)), a plasma lipoprotein implicated in cardiovascular disease. An individual Lp(a) particle consists of a neutral lipid core within a shell of phospholipid, cholesterol and glycoprotein. In principle, electron cryomicroscopy images of single particles should contain structural detail attributable to the density differences among these components and the surrounding buffer. We observed such structural detail in images of frozen, hydrated Lp(a) particles. Lp(a) particles appeared to be roughly spherical in shape with an average diameter of 210 A. As is generally true for unstained samples in vitreous ice, imaged with a low electron dose, these images have low contrast with low signal-to-noise ratios. To increase the signal-to-noise ratio, we averaged classes of similar particles. We began with a set of 5813 randomly oriented Lp(a) particles and generated classes using a linear multivariate statistical method, followed by hierarchical ascendant classification. Our initial classification, based on only the first eight eigenvectors, separated particles on the basis of gross size and shape. After a rough reference-free alignment step, a second classification used the finer details in the images. This approach yielded class averages with structural detail only faintly visible in the raw, single images.

Freezing↗