LITERATURE REVIEW Frederick W. Campbell, MD, Editor

SCIENTIFIC ARTICLES

Ferreria R, Burgus M, Milei J, et al: Effect of supplementing cardioplegic solution with desferox- amine on reperfused hemomyocardium. J Thorac Cardiovasc Surg 100:708-714,199O

A contribution by oxygen free radicals to the production of myocardial reperfusion injury in the human heart and its possible amelioration by iron chelating agents is demonstrated in this study. Fourteen patients undergoing myocardial revascularization were randomized to receive standard hypothermic cardioplegic solution or the same solution supplemented with desferoxamine, 100 mg/L. Myocardial biopsy specimens were obtained before and during reperfusion and assessed for chemiluminescence, an indirect measure of oxygen free radical activity, and for electron micro- scopic examination. An increase in chemiluminescence was ob- served in the standard cardioplegic solution group after ischemia and during reperfusion. This was not observed in the desferox- amine patients. Ultrastructural cell damage assessed by electron microscopy was also ameliorated in the treated group.

Willford DC, Moores WY, Ji S, et al: Importance of acid-base strategy in reducing myocardial and whole body oxygen consumption during perfusion hypo- thermia. J Thorac Cardiovasc Surg 100:699-707,199O

Whole-body and myocardial oxygen consumption were calcu- lated by Fick method in 10 anesthetized swine on cardiopulmonary bypass (CPB) cooled from 37°C to 27°C. Adjustment of ventilation during CPB to control arterial carbon dioxide tension was made to achieve a-stat conditions (pH 7.55 at 27°C) in 5 animals and pH-stat conditions (pH 7.41 at 27°C) in the other 5. The 10°C decrease in temperature reduced whole-body oxygen consumption to 50% of normothermic value in m-stat animals and to 75% of normothermic value in pH-stat animals. Myocardial oxygen con- sumption was similarly reduced to different degrees in the two groups. Measurement of plasma norepinephrine concentrations in 4 of the studied animals demonstrated significant increases in pH-stat-managed pigs in comparison to a-stat-managed animals. The authors postulate a pH-stat-associated activation of the sympathetic nervous system was responsible for the relatively higher oxygen consumption rates measured.

Charlson ME, MacKenzie CR, Gold JP, et al: Intraoperative blood pressure: What patterns identify patients at risk for postoperative complications? Ann Surg 212:567-580,199O

The effects of intraoperative blood pressure reductions on postoperative cardiovascular and renal function were assessed in 278 hypertensive or diabetic patients undergoing noncardiac sur- gery. The incidences of cardiac death, myocardial infarction, congestive heart failure, pulmonary edema, and renal dysfunction in the early postoperative period were increased in patients who

sustained decreases in mean arterial blood pressure (MAP) of 2 20 mm Hg for more than 60 minutes. Paradoxically, patients with MAP reductions ~40 mm Hg did not have an increased rate of complications. The effects of other hemodynamic or demographic variables on outcome were not studied. The usefulness and limitations of this study are discussed in an accompanying editorial by Reeves and Smith.

Craven TE, Ryu JE, Espeland MA, et al: Evaluation of the association between carotid artery atherosclero- sis and coronary artery stenosis: A case-controlled study. Circulation 82:1230-1242,199O

The relation of carotid atherosclerosis to coronary heart disease and to coronary artery disease risk factors was examined in 343 patients admitted for coronary angiography and 167 disease-free controls. Extent of carotid atherosclerosis was evaluated ultrasono- graphically and a B-mode score was computed, representing the sum of measurements of near and far carotid artery wall thickness at three sites bilaterally. There was a strong association between coronary status and extent of carotid artery disease in women and in men greater than 50 years of age. The relation does not exist in men younger than 50. The degree of carotid atherosclerosis assessed by B-mode score was found to be at least as useful as well known coronary artery disease risk factors for identifying patients older than 50 years with coronary artery disease.

Marmur JB, Freeman MR, Langer A, Armstrong PW: Prognosis in medically stabilized unstable an- gina: Early Holter ST-segment monitoring compared with predischarge exercise thallium tomography. Ann Intern Med 13575579,199O

The authors prospectively compare 24-hour Holter ST segment monitoring at admission, quantitative exercise thallium tomogra- phy, and cardiac catheterization 5 days after admission for predic- tion of a cardiac event within 6 months. Patients with a favorable outcome were distinguished from those with unfavorable outcome by higher maximum rate-pressure product and reversible scinti- graphic perfusion defect at exercise thallium tomography, and a smaller number of vessels with 2 50% stenosis at the catheteriza- tion. Holter ST segment shifts, exercise duration and exercise- induced ST depression during thallium tomography, and left ventricular ejection fraction at catheterization did not predict outcome. In the patient subgroup without previous myocardial infarction, reversible exercise thallium perfusion defect size was the only predictor.

Allen JK, Fitzgerald ST, Swank RT, Becker DM: Functional status after coronary artery bypass graft- ing and percutaneous transluminal coronary angio- plasty. Am J Cardiol65:921-925,199O

Two patient cohorts of comparative age with similar preproce- dure cardiac function who underwent coronary artery bypass

294 Journal of Cardiofhoracic and Vascular Anesthesia, Vol 5, No 3 (June), 1991: pp 294-296