Neurological complications after cardiopulmonary bypass: An update.

INTRODUCTION: Neurological complications are, at the present time, considered among the most important causes of morbidity and mortality after heart surgery. We evaluated their importance and risk factors. PATIENTS AND METHODS: We retrospectively reviewed 2, 528 consecutive patients who underwent cardiopulmonary bypass in a single center. In each one, we attended to previous vascular risk factors, such as surgical and postoperative events. We considered four categories of neurologic outcome: (1) persistent neurological focal deficits, (2) stupor or coma, (3) temporary neurological focal deficits, and (4) seizures. We carried out univariant and multivariant statistical analysis, looking for predictors of adverse neurologic events. RESULTS: Neurological complications occurred in 76 patients (3%); 36 of them (47%) had persistent neurological focal deficits, 18 (24%) stupor or coma, 18 (24%) temporary neurological focal deficits, and 27 (36%) seizures. Twenty-two patients with cerebral adverse outcomes died (29%), the overall mortality among the 2,528 cases being 5%. Predictors of risk were aortic aneurysm and aortic valve surgery, advanced age, female sex, and the use of intra-aortic balloon pump. A longer hospitalization time was noticed among patients with neurological side effects. DISCUSSION: Neurological complications are common and serious after heart surgery, as we have noticed with this series, the largest up to now, according to our review of the literature. They increase perioperative mortality and hospitalization time. Neurological morbidity and risk factors in our study are similar to those previously published.

[Neurological complications of aortic artery surgery]. / Complicaciones neurológicas de la cirugía de la arteria aorta.

INTRODUCTION: Improvement in cardiac surgery techniques has led to a considerable reduction in mortality following surgery of the aorta, dissection of the aorta and for aortic aneurysms. Although there are satisfactory vascular results following surgical repair, morbi-mortality related to neurological complications, both cerebral and spinal, is still very high. Repair of aortic lesions may lead to damage by two main mechanisms: ischemia secondary to prolonged obstruction of the aorta or to neurological lesions due to total circulatory arrest. DEVELOPMENT: After description of the mechanisms leading to cerebral and spinal lesions and the risk factors involved, we discuss methods of vascular protection and other means of neuro-protection, both spinal and cerebral. Of the vascular techniques for spinal protection, the most useful ones are short-circuits, or active or passive shunts, and cardiopulmonary by-pass. Amongst the vascular techniques for cerebral protection we describe total circulatory arrest and methods of anterograde and retrograde cerebral perfusion, and when these may be used. As general measures for nervous system protection, we describe the use of hypothermia and drugs such as corticosteroids, free radical blockers, antagonists of the excitatory amino-acids etc. CONCLUSIONS: In spite of the number of studies done, the extreme sensitivity of the nervous system to ischemia has meant that in few cases have encouraging results been seen. Neurological damage continues to be the main cause of morbi-mortality in patients with dissection or aneurysm of the aorta.

Hydatid cyst of the interventricular septum in a 3.5-year-old child.

An asymptomatic cardiac cyst located in the interventricular septum was diagnosed in a 3.5-year-old child by echocardiographic findings. Surgical ablation was done and histopathologic analysis confirmed a hydatid cyst. The patient was discharged without symptoms.

[The etiology of neurological complications after cardiopulmonary bypass surgery]. / Etiología de las complicaciones neurológicas tras cirugía extracorpórea.

INTRODUCTION: Cardiopulmonary bypass (CEC) in the surgical treatment of cardiac diseases may cause the appearance of neurological damage of an intensity which varies between minor neuropsychological disorders and global cerebral anoxia. There are two mechanisms for the production of these lesions: ischaemic and embolic. The mortality associated with this type of complication is low, but morbidity may be considerable. The neurological disorders derived from CEC may be classified according to the aetiology and clinical findings. In the first group are included: severe cerebral anoxia, embolic cerebro-vascular accidents, microvascular embolias, lesions of spinal vascularization and lesions of the peripheral nerves. In the second group are: encephalic focal lesions, convulsive crises, lesions of the extra-pyramidal system, alterations in the level of consciousness and neuropsychological disorders. METHODS: Quantification of neuronal damage has been attempted by: monitoring cerebral blood flow and neurone metabolism, EEG and study of intra-operative evoked potentials, echography of the carotid, cardiac and ascending aorta, transcranial doppler, fluorescein-angiography and the study of biochemical markers of neuronal and glial damage. Different studies have identified a series of factors which potentiate the risk of neurological lesions following CEC. These are: age, severe carotid disease, aortic atherosclerosis and previous cerebro-vascular haemorrhage, amongst others. An attempt is made to reduce the incidence of neurological complications by: pre-operative evaluation of carotid bruits, hypothermia, careful surgical technique and the use of drugs with a neuroglial protector effect. None of these methods gives sufficiently effective protection to the central nervous system subjected to the changes involved in the use of CEC. CONCLUSION: There are still many unknown aspects of neurone pathology in these circumstances, leaving a door open to investigation.

Role of epicardial pacing wire cultures in the diagnosis of poststernotomy mediastinitis.

Mediastinitis after cardiac surgery is difficult to diagnose in many cases. The transitory epicardial pacing wires used after surgery are placed in the mediastinum, so the culture of these wires could be useful for the diagnosis of this disease. To test this hypothesis, we routinely cultured the epicardial pacing wires of 565 patients undergoing extracorporeal circulation. Wires were removed on the 7th to 9th postoperative day under sterile conditions and were cultured with routine techniques used for the culture of venous catheters. Mediastinitis developed in 16 patients, and Staphylococcus aureus was the most common pathogen (81.25%). We had 103 positive and 462 negative cultures. There were 458 true-negative, 12 true-positive, 91 false-positive and 4 false-negative results. For mediastinitis in general, epicardial pacing wire culture has a sensitivity of 75%, specificity of 83.4%, positive predictive value of 11.6%, and negative predictive value of 99.1%. For Staphylococcus aureus mediastinitis, epicardial pacing wire culture has a sensitivity of 84.6%, specificity of 95.8%, positive predictive value of 32.3%, and negative predictive value of 99.6%. We conclude that a sterile culture of the epicardial pacing wires strongly contradicts a diagnosis of postsurgical mediastinitis.

Intracardiac thrombus trapped in a patent foramen ovale.

We describe a case of impending paradoxical embolism due to a thrombus trapped in a patent foramen ovale in a 22-year-old woman. Transthoracic and transesophageal echocardiography detected the thrombus. She was operated on and discharged asymptomatic.

[Aortic valve replacement via ministernotomy]. / Sustitución valvular aórtica por miniesternotomía.

Minimally invasive cardiac surgery is arising as an alternative technique in some cardiac operations. We present the first aortic valve replacement via ministernotomy. We describe in detail the technique of ministernotomy and the limitations that this new approach would have. We conclude with the advantages of minimally invasive cardiac surgery over conventional approach and review other techniques described in the literature.