Relationships between antithrombin activity, anticoagulant efficacy of heparin therapy and perioperative variables in patients undergoing cardiac surgery requiring cardiopulmonary bypass.

INTRODUCTION: A study on 149 cardiopulmonary bypass (CPB) patients was performed to elucidate possible relationships between antithrombin (AT) activity and a subject's clinical profile or surgery characteristics. METHODS: An initial dose (300 IU/kg) of heparin was administered before CPB. Additional boluses (100 IU/kg) were administered if the activated clotting time (ACT)≤460 s. AT activity and hematological parameters were determined preoperatively, during and after CPB, and at 12, 24, 36, and 48 hours post-intervention. RESULTS: 29.5% patients required an additional dose of heparin during CPB. Preoperative AT was 96.5 ± 13.9% in all but 4 patients. AT was significantly lower during CPB and upon leaving the operating room (59.7%-80.0%). A small, but significant, inverse correlation was observed between AT at the end of CPB and the patient's age, as well as between basal preoperative AT and total heparin administered. CONCLUSIONS: Patient's age could be a moderate indicator of AT activity drop and low preoperative AT activity could be a sign of reduced anticoagulant efficacy of heparin during CPB.

[Transfusion requirements, morbidity and mortality in cardiac surgery and the use of antifibrinolytic agents: a comparison of aprotinin and tranexamic acid]. / Requerimientos transfusionales y morbimortalidad en cirugía cardiaca en relación al empleo de antifibrinolíticos: aprotinina comparada con ácido tranexámico.

OBJECTIVE: To evaluate transfusion requirements, morbidity and mortality when 2 antifibrinolytic agents (aprotinin and tranexamic acid) were used in patients undergoing cardiac surgery. PATIENTS AND METHODS: Comparison of the effects of 2 antifibrinolytic agents in 243 patients undergoing cardiac surgery between December 2006 and June 2008. We recorded the surgical procedures used, blood product transfusions required, complications (particularly renal), mortality, and length of hospital stay. RESULTS: The patients were distributed into 2 groups to receive tranexamic acid (n = 144) or aprotinin (n = 99). The incidence of transfusion in the tranexamic acid group (31.94%) was nonsignificantly lower than in the aprotinin group (38.38%) (PF = .31). The mean (SD) number of units of packed red blood cells transfused was 0.67 (1.18) in the tranexamic acid group and 1.01 (1.54) in the aprotinin group (P = .07). The mean preoperative hemoglobin concentration in the tranexamic acid group (11.79 [1.71] mg/dL) was significantly lower than in the aprotinin group (12.35 [1.70] mg/dL) (P < .01). Incipient postoperative renal failure tended to occur more frequently in the aprotinin group (19.6% compared to 16%; P = .47). Mortality at 1 year was 9.02% in the tranexamic acid group (compared to 14.14% in the aprotinin group; PF-.21); the trend for mortality related to postoperative renal failure was similar (7.6% in the tranexamic acid group compared to 12.4% in the aprotinin group; P = .22). No significant differences were observed in postoperative complications or length of hospital stay. However, the lack of randomization and the small sample size do not allow for definitive conclusions. CONCLUSIONS: This study, subject to the aforementioned limitations, shows that tranexamic acid is as effective as aprotinin for reducing transfusion requirements in cardiac surgery in Spain.

[Mortality following cardiac surgery in the National Health Service Hospitals of the Community of Valencia in 2007: a descriptive analysis]. / Análisis descriptivo de mortalidad en cirugía cardiaca en los hospitales públicos de la Comunidad Valenciana en el año 2007.

OBJECTIVE: To analyze clinical records of cardiac surgery patients in an attempt to identify factors associated with mortality in the postoperative critical care units of the public health service hospitals in the Community of Valencia, Spain, in 2007. METHODS: Retrospective study of cases from January 1, 2007 to December 31, 2007. The charts of all patients who underwent cardiac surgery with or without extracorporeal circulation were reviewed. A data collection protocol was followed to obtain information on age, sex, body mass index (BMI), presurgical risk factors, type of surgery, duration of extracorporeal circulation, duration of ischemia, cause of death, and length of stay in the postoperative critical care unit. RESULTS: The study population consisted of 2113 patients at 5 public hospitals; 124 patients (70 men, 54 women) died. The mean (SD) age was 70 (9.43) years (range, 36-91 years). The mean BMI was 28.19 kg/m2 (maximum, 42 kg/m2). The mean Euroscore was 21.92 (maximum, 94.29). Hypertension was present as a preoperative risk factor in most patients (74.2%); dyslipidemia was present in 51.6%, diabetes mellitus in 38.7%, stroke in 73%, and renal failure in 2.4%. It was noteworthy was that the group who underwent coronary revascularization had the highest mortality rate (nearly 35% of the 124 patients). The next highest mortality rate (19.4%) was in patients who had combined procedures (valve repair or substitution plus coronary revascularization). Mortality was 18.5% in the group undergoing aortic valve surgery and 11.3% in those undergoing mitral valve surgery. The mean duration of extracorporeal circulation was 148.63 minutes. The mean duration of myocardial ischemia was 94.91 minutes. The most frequent cause of death was cardiogenic shock (54.8%). This was followed by distributive shock (29.8%) and hemorrhagic shock (8.9%). The mean length of stay in the postoperative critical care unit was 13.6 days. Overall mortality was 5.87%. CONCLUSIONS: The highest mortality rate among cardiac surgery patients in postoperative critical care units in hospitals in the Community of Valencia in 2007 was in patients who underwent coronary revascularization. The most prevalent preoperative risk factor was hypertension. Cardiogenic shock and distributive shock were the most frequent causes of death in these patients. A system for classifying risk is needed in order to predict mortality in critical care units and improve perioperative care.

[Knowledge of perioperative risk associated with use of medicinal plants]. / Estudio sobre el conocimiento del riesgo perioperatorio de las plantas medicinales.

OBJECTIVES: To assess physicians' knowledge of perioperative risk for patients who consume medicinal plants. To review interactions between drugs and the main medicinal plants with a view to justifying a plan for preoperative intervention. MATERIAL AND METHODS: Surgeons and anesthesiologists were sent an e-mail survey with questions on knowledge of and attitudes toward surgical patients' consumption of medicinal plants. At the same time, we performed a literature search on the species of plants that can interact with anesthetic and surgical processes. The species included were Allium sativum, Ephedra sinica, Echinacea purpurea, Ginkgo biloba, Panax ginseng, Hypericum perforatum, Piper methysticum, Glycyrrhiza glabra and Valeriana officinalis. The focus of the search was on indications for the use of these plants and their interactions with drugs. RESULTS: The questionnaire was sent to 131 physicians. The response rate was 80.5%. Twenty-two physicians had trained in Spanish hospitals and 3 in hospitals abroad. Medicinal plants were believed to be effective by 55%, but 78% did not ask patients about their use. Only 3% knew the interactions of some of the plants mentioned in the survey and only 7% knew that the use of some should be suspended before surgery. CONCLUSIONS: Medicinal plants are currently being used in our culture. In spite of appropriate warnings from such scientific bodies as the American Society of Anesthesiologists on timing the withdrawal of medicinal plants before surgery, our results indicate that the advice is not followed. We also found that physicians lacked knowledge of the indications for using these plants and their interactions, a situation which is alarming.

Role of the endothelium in the relaxation induced by propofol and thiopental in isolated arteries from man.

Induction of anaesthesia with intravenous propofol and thiopental is often accompanied by hypotension. This study evaluates whether propofol and thiopental induce relaxation of isolated arteries from man and whether this effect is modulated by the endothelium. Mesenteric artery rings (with and without endothelium) from 12 patients were placed in organ baths and precontracted with phenylephrine before addition of propofol (10(-3) M) or thiopental (10(-3) M). Relaxation induced by propofol and thiopental was evaluated for rings with intact endothelium in the presence of the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 10(-4) M) or the cyclooxygenase inhibitor indomethacin (10(-5) M). The vasodilator effect of propofol was similar for intact and denuded endothelium rings whereas the relaxation induced by thiopental was significantly attenuated in denuded-rings. In intact endothelium rings, L-NAME and indomethacin caused marked inhibition of the relaxation induced by thiopental, but not that induced by propofol. These results suggest that propofol induces endothelium-independent relaxation of isolated mesenteric arteries in man, whereas thiopental causes endothelium-dependent relaxation mediated by nitric oxide and prostaglandins.

[Role of antithrombin iii in cardiac surgery]. / Papel de la antitrombina iii en cirugía cardiaca.

Coagulation of blood is of multidisciplinary interest. Cardiac surgery produces major changes in the delicate balance between pro-and anti-coagulant serum factors. The role of antithrombin iii has been analysed after finding evidence that associated decreased levels of protein activity to postoperative morbidity and mortality. Supplementing exogenous antithrombin is considered with the aim of optimising outcomes. Its intrinsic anticoagulant and anti-inflammatory properties have stimulated a growing interest, and suggests new lines of research.