Postoperative hemostasis and fibrinolysis in patients undergoing cardiopulmonary bypass with or without aprotinin therapy.

Intra- and postoperative blood loss during open heart surgery is reduced by approximately 50% when aprotinin, a potent inhibitor for plasmin and kallikrein, is administered during surgery. But whether aprotinin increases the risk of thrombotic complications remains controversial. The aim of this study was to evaluate the effects of aprotinin administration on coagulation and fibrinolysis during and after cardiopulmonary bypass (CPB). Thirty patients undergoing CPB were randomly assigned to two comparable groups for a double-blind study (16 patients receiving high-dose aprotinin, 14 patients receiving placebo). Patients' plasma levels of ATM (thrombin-induced modified antithrombin III), FbDP (fibrin degradation products, D-Dimers), t-PA (tissue-type plasminogen activator) and PAI-1 (plasminogen activator inhibitor type 1) were measured at regular intervals. In both groups, ATM level increased during surgery (from less than 30 to 90-110 ng/ml) and returned to normal 24 h after surgery and remained unchanged thereafter. Aprotinin reduced this increase in ATM levels (p = 0.02 at 30 min after the start of CPB). The FbDP generated during surgery was greatly reduced in the aprotinin group (945 ng/ml) in comparison with the placebo group (1889 ng/ml, p = 0.004). After surgery, FbDP levels decreased in both groups with nadirs at 2nd day (placebo group: 940 ng/ml and aprotinin group: 865 ng/ml) indicating a hypofibrinolytic period. Then, the FbDP level in both groups started to increase up to the 9th day, in an identical manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of pulsed Doppler common carotid blood flow as a noninvasive method for brain death diagnosis: a prospective study.

Among the main causes for the relatively small number of organ donors, the delay in the diagnosis of brain death plays a major role. This prospective study was designed to evaluate whether pulsed Doppler mean and phasic common carotid blood flow (CCBF) combined with arterial and jugular venous blood gases could rapidly and specifically establish a diagnosis of brain death. CCBF was measured by an 8 MHz pulsed Doppler flowmeter, allowing measurement of the vessel diameter via a double transducer probe, which fixed the ultrasonic incidence angle. From an initial series of patients (n = 28) with an established diagnosis [brain death n = 14; severe coma with a Glasgow Coma Scale (GCS) less than 7, n = 14], the results of the logistic regression analysis process yielded the most discriminating parameters for brain death diagnosis: end-diastolic velocity (Ved - 1.4 vs. 12.7 cm/s; t = 7.67, P = 0.001) and blood flow (Qed - 13.6 vs. 121.4 ml/min). These parameters were then tested in a blind fashion on a second series of 28 comatose patients (GCS = 7). They resulted in correct diagnosis (brain death n = 14 or severe coma n = 14) for all patients. Brain death diagnosis was confirmed by clinical signs, EEG, and/or angiography. From the analysis of the overall population (n = 56), a value of Qed of less than 31.4 ml/mn indictes brain death. The authors conclude, that pulsed Doppler measurements of CCBF represent an early, low cost and noninvasive technique, the results of which may prompt legally accepted procedures, which in turn would reduce the delay required before brain death is diagnosed. Moreover, this technique could help in deciding on discontinuation of active therapy in severely injured patients.

A review of the renin-angiotensin system in the normal heart.

This review describes the vascular and cardiac tissue renin-angiotensin system (RAS), a so-called autocrine hormonal system as opposed to the circulating endocrine system. The existence of this autocrine system is suggested by the persistence of elevated concentrations of angiotensin II (Ang II) following binephrectomy. There is considerable evidence to support the concept of an autocrine RAS, but the functional aspects of such a system remain controversial: (a) Cultured endothelial cells from blood vessels can, for example, synthesize renin, but angiotensinogen messenger RNA (mRNA) is only present in perivascular adipocytes. (b) In the myocardium, there are obviously problems raised depending on the animal species considered: only rats apparently lack ventricular RAS, but tissue RAS is present in their atrial and conducting tissue system. In other species such as rabbit, the situation is quite different. In addition to the inotropic effect of Ang II, it has recently been demonstrated that this substance may determine the expression of the cardiac genome (oncogenes).

Comparison of perioperative and postoperative phasic blood flow in aortocoronary venous bypass grafts by means of pulsed Doppler echocardiography with implantable microprobes.

Although graft dimension and hemodynamic variables have been suggested as important determinants of the functional results of aortocoronary bypass grafting, there is no easy-to-use bedside method of monitoring phasic blood flow in coronary bypass grafts. We developed a miniaturized implantable silicone pulsed Doppler flow probe linked to a classic 8 MHz pulsed Doppler system. This apparatus has an adjustable range-gated time system that permits accurate measurement of diameter (D, in mm), cross-sectional blood flow velocity (Vm, in cm/sec), and coronary bypass graft flow (CBGF, in ml/min) as pi D2/4 X Vm X 60. Ten patients (55 +/- 7.2 years SD) with preoperative left ventricular ejection fractions over 45% received the implantable flow probes during the aortocoronary venous bypass procedure. Closure of the chest altered systolic and diastolic components of flow velocity and CBGF decreased from 131 +/- 65.8 to 94 +/- 55 ml/min (-28%; p less than .01). Comparison between early postoperative values (intensive care unit) and values 6 days later showed significant increases in diameter from 4.2 +/- 0.9 to 5.3 +/- 0.9 mm (p less than .01) and in CBGF from 130 +/- 112 to 204 +/- 86 ml/min (p less than .01). We conclude that the implantable pulsed Doppler microprobe is a sensitive bedside method for monitoring aortocoronary bypass graft diameter and blood flow in the postoperative period.

Response of left ventricular ejection fraction to recovery from general anesthesia: measurement by gated radionuclide angiography.

To test the hypothesis that, after anesthesia for noncardiac surgical procedures, the increased cardiac work during recovery induces wall motion and ejection fraction (EF) abnormalities in patients with mild angina pectoris, gated radionuclide angiography was performed in patients undergoing simple cholecystectomy under narcotic-relaxant general anesthesia. The ejection fraction was determined during anesthesia at the end of surgery, and then determined 3 min and 3 hr after extubation. A new angiography was performed 24 hr later, and a myocardial scintigraphy (Thallium 201) was performed during infusion of the coronary vasodilator, dipyridamole. In the first part of the investigation, eight patients without coronary artery disease (CAD) (group 1) and 20 patients with mild angina (group 2) were studied. In the second part of the study, seven patients (group 3) with mild angina pectoris received an intravenous infusion of 0.4 microgram X kg-1 X min-1 of nitroglycerin started before surgery and gradually decreased 4 hr after extubation. In group 1, EF remained unchanged at recovery. In contrast in group 2, EF responded abnormally to recovery: EF decreased from 55% during anesthesia to 45% 3 min after extubation (P less than 0.001). Patients in group 3, who received intravenous nitroglycerin, showed no change of EF at recovery. This study demonstrates that recovery from general anesthesia causes abnormalities in left ventricular function in patients suffering from CAD. These abnormalities are prevented by prophylactic intravenous nitroglycerin.

[Value of glyceryl trinitrate during the intraoperative period in patients operated on for coronary disease. Study of changes in the arterial pressure and heart rate]. / Intérêt de la trinitrine percutanée pendant la période opératoire chez l'opéré coronarien. Etude des modifications de la pression artérielle et de la fréquence cardiaque.

The aim of this study was to determine the changes in systemic blood pressure and heart rate observed at induction and during the immediate postoperative period in patients suffering from coronary artery disease who received a percutaneous preparation of nitroglycerin (PCNG) pre-operatively. In this randomized study, 23 patients with mild coronary disease were divided into two groups: in the 12 patients of group I, 30 mg of PCNG were applied 30 minutes before induction. The 11 patients of group II received a placebo. A slight increase in heart rate at induction, and a modest but significant decrease in systolic blood pressure both 15 minutes after application of PCNG and at induction were noted in group I. Systolic blood pressure increased during intubation in group II (placebo), but not in group I (PCNG). The systolic blood pressure recorded 5 minutes after extubation was greater in group II (placebo) than in group I (PCNG): X +/- SD: 141 +/- 13 vs 128 +/- 10 (P less than 0.01). Nitrate therapy should not be discontinued during the operative period in patients receiving oral nitrates for coronary disease; PCNG is a simple measure, particularly suitable for maintaining nitrate therapy in such patients. When administered before induction during the operative period, PCNG provoked neither tachycardia nor important decrease in systolic blood pressure which would mask the potentially beneficial effects of nitroglycerin.

Amiodarone and N-desethylamiodarone concentrations in plasma, red blood cells, and myocardium after a single oral dose: relation to hemodynamic effects in surgical patients.

In an attempt to assess their respective values for purposes of drug monitoring, plasma, red blood cell, atrial, and ventricular concentrations of amiodarone and N-desethylamiodarone (NDA) were measured, in 50 surgical patients, after a single oral dose (30 mg/kg); hemodynamic changes were assessed also. Amiodarone concentration was lower in red blood cells than in plasma and in myocardium. A relationship was found between the red blood cell concentration and plasma or myocardial concentrations of amiodarone (r = 0.79 and r = 0.68, p less than 0.00001). Hemodynamic studies were available in 17 treated patients and 13 control subjects before and at the time of surgery. In control subjects, hemodynamics did not change with time and general anesthesia. Oral amiodarone decreased the cardiac index (p less than 0.05) and heart rate (p less than 0.001) without significant changes in arterial pressure, systemic vascular resistance, or stroke volume index. The increase in capillary wedge pressure was related to amiodarone or NDA plasma, myocardial, and red blood cell concentrations (for amiodarone: r = 0.61, p = 0.006; r = 0.69, p less than 0.001; and r = 0.53, p = 0.02, respectively). We concluded that oral amiodarone impairs hemodynamics and that measurement of the amiodarone plasma concentration rather than the red blood cell concentration is the easiest method of monitoring the drug. However, establishment of the clinical utility of drug monitoring during chronic administration of amiodarone needs further investigation.

[Cervical arteriovenous fistulas after internal jugular catheterization]. / Fistules artério-veineuses cervicales après cathétérisme jugulaire interne.

The vertebral artery and vein are mostly involved, but other sites exist, especially between the inferior thyroid artery and the internal jugular vein. Five cases were treated in our department. All the fistulas were closed by percutaneous transarterial occlusion with a detachable balloon. The mechanisms of fistula formation are discussed. The different therapeutic methods (surgical ligature and endovascular occlusion) are discussed. It would appear the endovascular method gives the best results.

Left ventricular dysfunction after non-cardiac surgical procedures in patients with ischemic heart disease.

In order to demonstrate the presence of postischemic ventricular dysfunction after non-cardiac surgical procedures, myocardial perfusion scintigraphy with thallium 201 and radionuclide ventriculography were performed before and 24 h after intervention in 20 patients suffering from angina pectoris. A long-term ECG recording was used in all patients to detect peroperative myocardial ischemia. In 14 of the 20 patients studied, both ventriculography and thallium scintigraphy were unchanged at the postoperative study. Comparison of pre- and postoperative radionuclide data revealed an increased deficit in one patient, both increased deficit and decreased ejection fraction in four others and a decreased ejection fraction in one other. In these five last patients, continuous ECG recording demonstrated the occurrence of peroperative ST segment depression. These results underline the part played by prolonged peroperative episodes of myocardial ischemia in the occurrence of postoperative left ventricular dysfunction.

[Fatal hypoxemia following extracorporeal circulation for aortocoronary bypass. A case]. / Hypoxémie mortelle après circulation extra-corporelle pour pontage aorto-coronarien. Une observation.

A lethal case of acute respiratory distress syndrome of the adult following extracorporeal circulation for aorto-coronary bypass is reported. This case illustrates the two mechanisms currently thought to be responsible for this pathology: (1) the passage of blood over the synthetic fibres of the cardiopulmonary bypass machine activates the complement, and the systemic inflammatory reaction that ensues accounts for the increased permeability of the alveolar capillary membrane; (2) the haemodilution inherent in extracorporeal circulation explains the hypoproteinaemia usually observed at the end of the procedure; the resulting fall in capillary osmotic pressure upsets the equilibrium of pressures in the capillary vessels.

Radionuclide assessment of cardiac function. Pre-operative evaluation of patients with abdominal aortic occlusive disease undergoing aortobifemoral bypass grafting.

Pre-operative radionuclide angiography, a non-invasive technique for evaluating ventricular function, was performed on 34 consecutive patients undergoing aortobifemoral bypass grafting for abdominal aortic occlusive disease, to determine whether pre-existing coronary artery disease causes significant modification of cardiac function. Patients were divided into two groups according to medical history. Group I had 23 patients with no symptoms of coronary artery disease and Group II had 11 patients, six with previous myocardial infarction and five with angina pectoris. There was a significant difference in left ventricular ejection fraction and in cardiac output between these two groups. A flow-directed pulmonary artery catheter was inserted in eight patients in Group II who had an ejection fraction less than 50% and a nitroglycerin infusion was used in six cases to maintain pulmonary capillary wedge pressure below 20 mmHg. In the other patients, only central venous pressure was monitored. All patients had uneventful operative courses. It is concluded that left ventricular function is significantly altered in patients with symptoms of both abdominal aortic occlusive disease and coronary artery disease. By contrast, cardiac function is normal in patients free from symptoms of coronary artery disease, and central venous pressure monitoring seems sufficient in the management of these patients during aortobifemoral bypass grafting.

[Complement activation during extracorporeal circulation. A model for understanding lesional pulmonary edema]. / Activation du complément au cours de la circulation extra-corporelle. Un modèle pour comprendre l'oedème pulmonaire lésionnel.

The complement system (CH50, C3, C4, C3 PA) was monitored during extra-corporeal circulation in 10 patients with ischemic-heart disease. Mean concentrations of CH50, C3, C4, and C3 PA significantly decreased as early as 5 minutes after initiation of the extra-corporeal circulation and decrement remain steady all over the surgical procedure. Transient neutropenia occurred early during the procedure. A significant hypoxemia was present only 24 hours after surgery. We suggest that a complement mediated leukostasis might occur with sequestration in the lungs and contribute to endothelial cell damage with pulmonary edema known as the "post-pump syndrome".

[Acute postoperative pulmonary edema in the coronary patient: effects of myocardial ischemia]. / Oedème aigu pulmonaire postopératoire chez le coronarien: incidence de l'ischémie myocardique.

In order to evaluate the incidence of myocardial ischaemia in patients who developed acute pulmonary oedema during the immediate post-operative period, continuous monitoring of the electrocardiogram by the Holter method was used in 200 consecutive patients with coronary artery disease. Fourteen of these patients exhibited ST segment depression during the post-operative period and 13 during surgery. Nine patients developed acute pulmonary oedema immediately after the operation and in 7 cases the oedema was preceded by myocardial ischaemia. A continuous nitroglycerin infusion brought about regression of the pulmonary oedema in 8 cases. One patient died despite treatment. These findings underline the part played by myocardial ischaemia in the pathogenesis of acute post-operative pulmonary oedema in patients with coronary artery disease.