Determinants of survival after aortic valve replacement as treatment for symptomatic aortic valve disease in the elderly.

BACKGROUND AND AIM OF THE STUDY: The effect of concurrent disease and cardiac comorbidity on survival after bioprosthetic valve replacement in elderly patients was assessed retrospectively. Risk factors were categorized as general, non-cardiac (age, diabetes, previously treated carcinoma) and cardiac (LVEF, three-vessel disease, previous CABG or valve replacement, and endocarditis). METHODS: A total of 400 elderly patients (median age 73 years; range: 71-76 years) was studied. Medical history included diabetes, previous CABG or aortic valve replacement (AVR), endocarditis and treatment of previous carcinoma. A left ventricular ejection fraction (LVEF) of <0.66 and presence of three-vessel disease were also investigated. Hospital deaths (and cause) were recorded; survival or date and cause of death after discharge were obtained by questionnaire. Kaplan-Meier univariate and Cox proportional hazards multivariate regression analyses were carried out. RESULTS: Mortality during follow up was 28.3%; hospital mortality was 3.8%. Univariate analysis showed five factors significantly to affect survival: LVEF, history of endocarditis, carcinoma, age and three-vessel disease. Fifteen of 38 patients with history of carcinoma died, 10 due to a malignancy. Of 76 patients with three-vessel disease, 26 died. A history of diabetes and previous CABG did not influence survival significantly. Four of eight patients with preoperative endocarditis died, all in hospital. Six of 11 patients died after redo-AVR, none before 36 months follow up. By Cox regression analysis, LVEF and histories of carcinoma and endocarditis remained significant. CONCLUSION: AVR should be performed before ventricular deterioration occurs. Previous CABG is not a contraindication for AVR. Endocarditis impaired survival. Long-term mortality after redo-AVR in this population was relatively high, but acceptable. AVR should also be performed in elderly patients with aortic valve disease. Since prognosis of symptomatic aortic valve disease is poor in the short term, AVR is indicated in patients treated for carcinoma.

Venous occlusion plethysmography with mercury-in-rubber strain gauges.

The Whitney plethysmograph consists of a mercury-in-rubber strain gauge together with a Wheatstone bridge. It can be used to measure, in a non-invasive way, the blood flow in extremities. A simple theoretical and practical study is lined out, showing that the apparatus is fully acceptable for clinical use. (Acta anaesth. belg., 1980, 31, 5-14).

Circulatory changes during a hypotensive technique of anesthesia.

The blood circulation and the oxygen consumption of the tissues during general hypotensive anesthesia for stapes surgery is quantitatively studied on 40 patients. The rate of oxygen consumption of the whole body and of the tissue of an upper extremity is determined together with the rate of blood flow in that extremity. A series of other parameters such as the PaCO2 and the acid-base balance of arterial and venous blood, the blood pressure, the pulse frequency and the temperature are also measured. Most measurements are performed before premedication, after premedication and after surgery. The state of the patient in the immediate postoperative period is completely comparable with the peroperative anesthetic state. Some of the parameters mentioned above are measured also on a series of 8 normal persons at awake and at asleep state. The numerical results show clearly that the used type of general anesthesia "Protected Sleep" obeys the demands necessary for performing microsurgery of the ear in a successful way. (Acta anaesth. belg., 1980, 31, 15-27).

[Anesthetic technics for surgery in otoneurology]. / Techniques anesthésiques pour les interventions en oto-neurologie

A description is given of a technique named "Protected Sleep", which produces a deep and residual analgesia and neurolepsia, without interfering with spontaneous respiration. A deep, stable and reliable neuroanesthesia is achieved by means of a partial pharmacodynamic blockage of the neuro-humoral reaction system. It is recognisable by the following features: 1 degree a smooth transition through pre-, per- and post-operative stages, avoiding in particular immediate awakening; 2 degrees a relative arterial hypotension, low venous pressure good peripheral circulation and tissular perfusion; 3 degrees light hypothermia; 4 degrees completely spontaneous respiration. This last factor is, to our way of thinking, of great importance: The venous return remains physiologically unchanged during inspiration in the peroperative as well as in the pre- and postoperative phases, enabling the maintenance of a constant, low venous pressure. Furthermore, should danger exist, the preservation of spontaneous respiration facilitates the immediate control of the respiratory centre. In this way we can obtain: 1. An almost perfect bloodless surgical field with good conditions for dissecting. 2. A low cerebro-spinal fluid pressure. 3. Decreased brain volume. 4. Absence of postoperative haemorrage. 5. Little of no postoperative oedema. 6. Little or no postoperative hyperthermia. "Protected sleep" is a pharmacodynamic technique realised mainly through administration of a combined and sufficient dose of pethidine, N-allyl-normorphine and levome promazine. For induction, a given dose of diazepam is combined with a single dose of succinyl-choline, to facilitate intubation, followed by a large dose of the narco-neuro-leptanalgesic mixture. For maintenance, nitrous oxide, oxygen, methoxyflurane and additional doses of the mentioned mixture are administered. Undirectional gas flow, without rebreathing, is provided, using the Ruben valve. In this paper on neuroanaesthesia, the technique of "Protected Sleep" and the pre-, per- and postoperative management and positioning of the neurosurgical patient are described in detail.

Coagulant fractions of snake venom and the control of capillary bleeding during microsurgery of the ear in vivo demonstration.

In 398 cases of observed capillary bleeding out of total of 968 otological microsurgeries, the i.v. use of Bothrops Jararaca enzyme proved to be highly useful in controlling the bleeding in 79% of those, namely in 318 cases. We may assume that if capillary bleeding is indeed the consequence of some haemostatic deficiency, not always detectable with the routine laboratory preoperative tests, Bothrops Jararaca enzyme is extremely valuable in controlling this bleeding. If however oozing or capillary bleeding is the result of other circumstances, such as insufficient analgesia and neurolepsia, inadequate anaesthetic technique, wrong positioning of the head resulting in venous congestion of the operative region, or local fibrinolysis due to protracted microsurgery, other measures should be taken to correct these conditions which are not due to coagulation defects. Bothrops Jararaca enzyme, given by i.v. route, even in single dose of 2-6 units = 2-6 ampoules, was perfectly tolerated by all the patients without any side effect or allergic manifestations.