Jugular venous oxygenation during hypothermic cardiopulmonary bypass in patients at risk for abnormal cerebral autoregulation: influence of alpha-Stat versus pH-stat blood gas management.

In a prospective, randomized study of cardiac surgical patients at risk for impaired cerebral blood flow autoregulation, we compared alpha-stat and pH-stat blood gas management. The 40 patients enrolled had age >70 yr, diabetes, prior stroke, or uncontrolled hypertension. During hypothermia and early rewarming, jugular oxygen tensions were significantly lower in alpha-stat patients (n = 12) than pH-stat patients (n = 19; P < 0.05). During rewarming, jugular venous desaturation (i.e., SjvO(2) <50%) occurred in 6 of 12 alpha-stat patients, but no pH-stat patients (P = 0.0006). Patients at risk for poor cerebral autoregulation have higher oxygen tensions and saturations if pH-stat blood gas management is used during cardiopulmonary bypass.

Hormone replacement therapy is associated with improved survival in women undergoing coronary artery bypass grafting.

OBJECTIVES: The effect of hormone replacement therapy on cardiovascular events in postmenopausal women is controversial. We investigated the roles of sex and hormone replacement status in female patients undergoing coronary artery bypass grafting. METHODS: We reviewed the records of 4259 consecutive patients aged 55 years or older who underwent primary elective isolated coronary artery bypass at our hospital between May 1996 and September 2001. RESULTS: Female sex with hormone replacement therapy was an independent predictor of decreased mortality, regardless of age. Mortality was 6.7% (61/905) for women not receiving hormone replacement therapy, 2.3% (6/256) for hormone replacement therapy recipients, and 2.7% (82/3098) for men (P <.01 for all comparisons). Of the characteristics examined, multivariate analysis indicated that independent predictors of mortality were advanced age, previous congestive heart failure, class IV angina, and female sex without hormone replacement (P <.005). Independent predictors of survival included use of an internal thoracic artery graft and white ethnicity. There were no significant intergroup differences in the incidence of nonfatal, morbid postoperative events. CONCLUSIONS: Postmenopausal women undergoing coronary artery bypass had a significantly improved in-hospital survival if they had been receiving hormone replacement therapy. The improved survival might be related to one or more of the numerous cardiovascular effects of estrogen that are considered beneficial. A prospective randomized trial is needed to validate the observation that hormone replacement therapy is protective in this setting.

Acute effects of 17beta-estradiol on left internal mammary graft after coronary artery bypass grafting.

BACKGROUND: Vasospasm of arterial conduits used for coronary surgical procedures is an important cause of postoperative graft failure. Mounting experimental evidence suggests that estrogen reverses acetylcholine-induced vasospasm of the coronary arteries in animals and humans. Estrogen also affects endothelium-derived constrictor factors. We therefore investigated the in vivo vasomotor responses to transdermal 17beta-estradiol of the left internal mammary artery (LIMA) grafted on the anterior descending coronary artery. METHODS: We studied 20 women, mean age of 62 +/- 7.2 years (range, 48 to 73 years), who had undergone cardiopulmonary bypass for coronary artery bypass grafting. They received transdermal 17beta-estradiol on the fifth day after operation. The diameter, cross-sectional area, and blood flow of the LIMA graft were measured by transthoracic color Doppler echography before (basal values) and after the transdermal administration of 50 microg of 17beta-estradiol (control). RESULTS: LIMA graft vasodilation after the administration of 17beta-estradiol was observed. A significant increase in diameter (2.06 +/- 0.4 mm versus 2.37 +/- 0.28 mm; p = 0.035) and cross-sectional area (3.45 +/- 1. 2 mm2 versus 4.24 +/- 1 mm2; p = 0.039) was registered. The LIMA graft mean flow increased by 49% (44.76 +/- 27.19 mL/min versus 56.62 +/- 27.69 mL/min), but this increase was not statistically significant (p = 0.06). CONCLUSIONS: The acute postoperative transdermal administration of 17beta-estradiol induced a significant increase of LIMA graft diameter and cross-sectional area in postmenopausal women who underwent coronary artery bypass grafting. The LIMA graft vasodilation was also associated with an improvement in LIMA blood flow.