[Atrial fibrillation: from cardiology to perioperative management]. / Fibrillation atriale en anesthésie-réanimation : de la cardiologie médicale à la période périopératoire.

Atrial fibrillation (AF) is the most frequent arythmia. During the perioperative period and in intensive care units, management of patients with AF is frequent and difficult. As in cardiology, two main issues are present: the risk of acute hemodynamically instability and the risk of thromboembolic complication. Cardiological guidelines recently published must guide the management of patients in this context. Two main factors must be kept in mind: acute AF in these situations are often of short duration; the risk of anticoagulation can be superior to the risk of thrombotic complication in this situation. An individualized benefit-risk analysis must be done in each patient. New treatments, antiarrhythmic or mainly antithrombotic drugs, are under evaluation and will be soon available.

Incidence and risk factors of early thromboembolic events after mechanical heart valve replacement in patients treated with intravenous unfractionated heparin.

OBJECTIVE: To evaluate the incidence and risk factors, including timing and intensity of anticoagulation, of early thromboembolic events (TE) after mechanical heart valve replacement (MHVR) in patients treated by intravenous unfractionated heparin (IVUH). DESIGN: Prospective observational study, conducted between December 2005 and May 2007. SETTING: Haemostasis laboratory, surgical intensive care unit and ward in a university hospital. PATIENTS: Three hundred consecutive patients undergoing MHVR. Mitral or double MHVR was performed in 149 patients, and aortic MHVR in 151 patients. Postoperative anticoagulation was achieved with continuous IVUH according to a standardised protocol. The timing of efficient anticoagulation was recorded for each patient. MAIN OUTCOME MEASURES: The end point was the occurrence of any arterial TE from day 1 to day 30. Transoesophageal echocardiography was systematically performed after mitral MHVR. RESULTS: Early TE occurred in 22 patients (14.8%; 95% CI 9% to 20%) after a mitral or double MHVR and in two patients (1.3%; 95% CI 0% to 3%) after an aortic MHVR (p = 0.005). After adjustment for diabetes mellitus (adjusted OR (aOR) = 3.3; 95% CI 1.0 to 10.9, p = 0.049), and for the presence of predisposing factors (heparin-induced thrombocytopenia or bradycardia requiring definitive pacemaker implantation) (aOR = 12.8; 95% CI 3.1 to 53.3, p<0.001), effective anticoagulation on day 3 was a protective factor (aOR = 0.28; 95% CI 0.1 to 0.8, p = 0.018) for early TE after mitral MHVR. CONCLUSIONS: Despite the use of IVUH, the rate of early TE after mitral MHVR remained elevated. These results suggest that early effective anticoagulation is required after mitral MHVR, since inappropriate anticoagulation on day 3 was significantly associated with early TE.

[The use of cardiac troponins (T or I) measurement in cardiology and various clinical settings]. / Dosage des isoformes cardiaques des troponines T ou I: intérêt en cardiologie et en anesthésie-réanimation.

Measurement of cardiac troponin I or T in serum (highly specific for the myocardium) have replaced classical markers, such as creatine kinase MB. Cardiac troponins are preferred markers because of their high specificity and sensitivity. This had led to modifications of the original World Health Organization criteria for acute myocardial infarction. Furthermore, the place of the troponins as superior markers of subsequent cardiac risk in acute coronary syndrome has now become firmly established, for both diagnostic and risk stratification purposes. The use of C-reactive protein and/or other inflammatory biomarkers may add independent information in this context. After non cardiac surgery, the total cardiospecificity of cardiac troponins explains why other biomarkers of necrosis should no longer be used. Recent studies suggest that any elevation of troponin in the postoperative period is indicative of increased risk of long-term cardiac complications. This prognostic value has been previously demonstrated in other clinical settings such as invasive coronary intervention (surgical myocardial revascularization and percutaneous coronary intervention) and after heart valve surgery. Increases of troponin indicate cardiac damage, whatever the mechanism (ischemic or not). Other causes of cardiac injury include: pulmonary embolism, myocarditis, pericarditis, congestive heart failure, septic shock, myocardial contusion. In most cases, elevation of troponins has been shown to be associated with a bad outcome.

[Anesthesia of hypertensive patients]. / Anesthésie du malade hypertendu.

Hypertension is a frequent condition among adults. It is one of the major risk factors of atherosclerotic diseases. Anesthetologists are frequently confronted to the management of treated or untreated hypertensive patients whose major risk during that period concerns the potential association with coronary artery disease. Therefore, the preoperative assessment should be insured of an adequate control of blood pressure, the presence of potential target organ damage and especially the detection an underlying coronary disease and its importance. The risk of cardiovascular complications and consecutively the preoperative check-up depend of the type of surgery scheduled. Preoperative systolic blood pressures (SBP) below 180 mmHg and diastolic blood pressures (DBP) below 110 mmHg are recommended. Due to their efficacy, tolerability and the easiness of their use, dihydropyridins and beta-blockers are the most frequent drugs used in the peri-operative period. Many studies evidenced the benefit of beta-blocking agents in patients with definite or potential coronary artery disease during the immediate period of major surgery, with not only a decrease of serious cardiac complications and post-operative mortality but also an improvement of mid- and longterm prognosis. There is no evidence to privilege any type of anesthesia. A respect of hemodynamic conditions (avoidance of severe hypotension and tachycardia) reduces the incidence of ischemic complications. The hemodynamic stability is obtained with an adapted anesthesia and the use of intravenous vasoconstrictive or vasodilator agents as well as beta-blockers (esmolol). The diagnosis of perioperative myocardial infarction is based on the measurement of seric concentrations of cardiac Troponin isoforms (TnI or TnT).