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Biomedical subjects

J Ivanov

Publications and source records attributed to J Ivanov.

112 records · Page 7Linked to original sources
PubMedDate not supplied

Mitral valve replacement: mechanical versus bioprosthetic valves--a clinical review.

A review of the literature was conducted in an attempt to justify the exclusive use of either mechanical or tissue prostheses in the mitral position. In addition, the University of Toronto experience with mitral valve replacement was reviewed, including a five year follow-up from the Toronto General Hospital. Both studies concluded that there was no significant advantage for the use of either type of valve based upon freedom from thromboembolism, freedom from anticoagulant-related hemorrhage and freedom from all valve-related mortality/morbidity. Tissue valves were shown to be significantly poorer substitutes in terms of freedom from primary valve failure (P less than 0.05) and freedom from reoperation due to valve-related complications (P less than 0.07). The clinical results from the Toronto General Hospital correlated with those reported in the literature and suggested the preferential use of mechanical valves during mitral valve replacement based primarily on their durability and a consequent lesser need for reoperation.

Bioprosthesis↗
PubMedDate not supplied

The effect of lactate infusion on myocardial metabolism and ventricular function following ischemia and cardioplegia.

Impaired myocardial fatty acid and glucose metabolism following ischemia and cardioplegia may limit the recovery of myocardial oxidative metabolism and ventricular function. Lactate, a simple three carbon compound, can be readily metabolized to pyruvate and is possibly the preferred substrate for aerobic metabolism. Therefore, increasing arterial lactate concentrations may improve myocardial metabolic recovery after ischemia and cardioplegia. Myocardial lactate metabolism and ventricular function were assessed in a canine model of 45 mins of global normothermic ischemia followed by 60 mins of cold potassium cardioplegic arrest. Thirteen dogs received a perioperative infusion of sodium lactate to elevate arterial concentrations (from 6 to 12 mmol/L) and 12 dogs received an equivalent amount of saline. The high arterial lactate concentrations were associated with an increased myocardial lactate consumption and oxidation (as assessed by 14C-labelled lactate) during reperfusion. Myocardial ATP concentrations fell during reperfusion despite improved myocardial oxidation. The recovery of ventricular function (as assessed by a compliant intraventricular balloon) was incomplete and only marginally better with the high arterial lactate concentrations. An infusion of lactate improved myocardial oxidative metabolism following ischemia and cardioplegia. However, the recovery of ventricular function was incomplete perhaps because of inadequate preservation of myocardial ATP.

Adenosine Triphosphate↗