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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During aortic clamping, drug protection of the myocardium, far from supplanting hypothermia, complements it, particularly in the case of left ventricular hypertrophy. Ultramicroscopy and new techniques of histobiological exploration of the myocite have enabled one to distinguish the lessions provoked by anoxia from those induced by reperfusion. At present, drug protection, extended to energetic solutions and electrolytes, aim at preserving energy metabolism by stocking of the substrate and at avoiding interferences which precipitate exhaustion of the adenosine triphosphate and phosphocreatinine reserves. In order to do this, hemodilution in particular is limited in subjects with decompensated cardiopathy; choice of anesthetics is orientated towards neuroleptanalgesia or fluothane, and it is attempted to neutralize the adrenergic reaction by the use of beta-blocking substances. Furthermore, it is preferred to interrupt electrogenesis at the stage of polarization: depolarizing cardioplegic solutions rich in potassium and sodium are rejected and in preference membrane stabilizers are used (procaine, magnesium, tetrodoxine...) The ultramicroscopic analysis of the structural modifications leads to sparing of the integrity of the lysosomial membrane by corticoids and alkalines. The use of calcium is deferred, anti-calcium techniques are even proposed (washing poor in calcium, verapamil). Cellular edema is prevented and treated by solution (mannitol - sorbitol) whose osmolarity must be less than 300 M osm/l. A conditioning of the biochemical and physicial structures and of cardiac work is being more and more thought of which leads to the classification of beta stimulating substances as negative, and their indications must be seriously thought of and used with reserve.
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PMID:[Drug protection of the myocardium during cardiac surgery]. 1 31

After induction of left ventricular hypertrophy by supravalvar constriction of the ascending aorta in mini pigs (ATP and lactate) were measured under different cardioplegic conditions. In normothermia and plain anoxic arrest ATP decrease and lactate increase were significantly slower in hypertrophied myocardium compared to normal myocardium. Injection cardioplegia using magnesium-aspartate-procaine at 37 degrees C did not influence the ATP decrease and lactate increase in the hypertrophied ventricle, whereas in the normal heart it showed some protection according to these parameters. Optimal ATP preservation and the lowest lactate increase rate were achieved in left ventricular hypertrophy by combined application of magnesium-aspartate-procaine and hypothermia of 25 degrees C. We conclude that normothermic injection cardioplegia has no protective effect on the hypertrophied left ventricle, whereas additional hypothermia can improve magnesium-aspartate-procaine cardioplegia significantly.
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PMID:[The protective effect of magnesium-aspartate-procaine cardioplegia on the hypertrophied left ventricle of the mini-pig (author's transl)]. 15 67

Profound topical hypothermia for intraoperative protection of the heart has been employed as an alternative to selective coronary perfusion with excellent clinical results. Based upon observations that hypothermia decreases cellular metabolism and prevents cellular damage from anoxia, topical hypothermia has been employed to provide protection for anoxic intervals exceeding 60 minutes. Additional advantages of this technique include a bloodless operative field with a flaccid myocardium. A continuous infusion of saline at 4 degrees C provides a simple and effective method of creating myocardial hypothermia. While topical hypothermia has been used successfully with anoxic intervals of 120 minutes, recent evidence indicates that in patients with combined coronary disease and ventricular hypertrophy, the degree of protection is inadequate after 70 minutes. Further investigation is needed to define more completely the degree and length of protection and to identify those situations in which the protection becomes inadequate.
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PMID:Topical hypothermic protection of the myocardium. 80 73

Twenty-two patients with congenital valvular aortic stenosis were surgically treated between 1967 and July 1975. Five (23%) were under 1 year of age (group I) and 17 (77%) were between 2 and 24 years (group II). All infants exhibited severe congestive heart failure and electrocardiographi (ECG) evidence of left ventricular hypertrophy (LVH) with strain pattern. In group II, angina was present in three cases, syncope and fatigue in two; the ECG indicated LVH in 10 cases (59%) with strain pattern in five (29%). A bicuspid aortic valve was present in 77% (17/22) of the cases; 32% had other cardiac anomalies. Aortic valvotomy was performed on cardiopulmonary bypass in 20 cases, and with deep hypothermia and circulatory arrest in two. Three infants under 1 month of age with associated anomalies died (hospital mortality 14%). Intraoperative average peak left ventricular-aortic systolic pressure gradient decreased from 86 to 21 mmHg (P less than 0.001). Late clinical (in all cases) and haemodynamic (26%) follow-up showed severe restenosis in two patients of group II; one of them had a second operation, the other one died three and a half years postoperatively. Results assessed on the basis of symptoms, ECG changes, aortic valve function, and/or haemodynamic findings were fair in the two surviving infants. Results in group II were excellent in three, satisfactory in seven, fair in four, and poor in two cases. In infants, aortic valvotomy is a palliative procedure which carries a high risk. In the older age group, early and late results are more gratifying.
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PMID:Surgical treatment of congenital valvular aortic stenosis. 96 96

The risk of open heart surgery can be lowered by combination of different methods of myocardial protection. 1. Cardioplegia with a potassium free Mg-1-aspartate and Procaine-solution (Cardioplegin). 2. Coronary perfusion after ischemia longer than 35-40 minutes in case of excessive left ventricular hypertrophy or failure. 3. Hypothermia. Surface cooling gives an additional safety if coronary perfusion is not ideal possible in case of multiple coronary stenoses. For patients with this dispositions a continuous coronary perfusion with cardioplegic solution might be advisable, as it was presented by Gercken in his paper. This method was used three times already in human, but is still in an experimental stage.
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PMID:Induced ischemic cardiac arrest. Clinical and experimental results with magnesium-aspartate-procaine solution (Cardioplegin). 119 31

Hypothermia is believed to be the most important aspect of successful myocardial protection with retrograde coronary sinus cardioplegia. Because nutritive capillary flow to the right ventricle and septum is thought to be diminished with retrograde perfusion, these areas of the myocardium are considered at higher risk for intraoperative deterioration without the added protection of hypothermia. Recently we introduced warm aerobic arrest as an alternative to conventional methods of myocardial protection. We present our clinical results in 37 patients with mitral valve disease (+/- aortic valve, aortic root, or coronary artery disease) who underwent various cardiac procedures for which warm blood cardioplegic solution was delivered continuously via the coronary sinus after antegrade arrest. Thirty-five of the patients were in New York Heart Association class III or IV, and 19 patients had grade 3 or grade 4 left ventricular function. Sixteen patients had pulmonary hypertension, three with suprasystemic pressures, and marked right ventricular hypertrophy. Two patients had associated left ventricular hypertrophy. Nearly all patients returned to normal sinus rhythm shortly after removal of the aortic crossclamp, and they were easily discontinued from cardiopulmonary bypass even with crossclamp times of 3 hours. The 30-day hospital mortality rate was 2.7%. The perioperative myocardial infarction rate was 5.4%, and the prevalence of low-output syndrome was 10.8%. The results suggest that retrograde coronary sinus perfusion of blood cardioplegic solution at 37 degrees C is an effective method of myocardial protection even in patients with pulmonary hypertension at high risk for right ventricular failure. Its efficacy in this circumstance does not reside in its ability to deliver hypothermia.
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PMID:Warm retrograde cardioplegia. Protection of the right ventricle in mitral valve operations. 834 Oct 80

A 9-year-old girl was admitted with hypertension and severe congestive heart failure. Upon physical examination, a discrepancy of blood pressure between arm and leg was noted. Aortography revealed narrowing about 5 cm in length at the midportion of the descending thoracic aorta. Bypass operation of the narrow segment was performed under mild hypothermia with the diagnosis of atypical coarctation of the aorta. It was supposed that the patient might outgrow the graft and the graft would become too small for grown-up patient in diameter and length, then the haemodynamics would become less satisfactory and too much tension on the suture line would occur. A woven Dacron graft, 10 mm in diameter, 15 cm in length, was anastomosed proximally and distally to the coarcted segment at a distance of about 6 cm. So, the graft was disposed in a C-shaped configuration. It was expected that the arch of the graft would open more widely with increase of her stature, even if the graft does not increase in length. She has been followed for twelve years. Hypertension of upper extremity and arm-to-leg gradients of the systolic blood pressure were recognized from two years after the operation, particularly with exercise. However, cardiomegaly and left ventricular hypertrophy in ECG were improved. She appears to have been developing normally with no cardiac symptoms. Estimating from angiography, the distance between proximal and distal anastomoses stretched about 2 cm during the period of rapid growth, though calcification of the graft had been seen from four years after the operation, perhaps due to increased calcium turnover in childhood.
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PMID:[Bypass operation adaptable to stature increase in child with atypical coarctation of the aorta]. 277 55

Many patients undergoing cardiac surgery have some degree of myocardial hypertrophy. To assess the response of hypertrophied myocardium to simulated cardiac surgery, left ventricular hypertrophy was induced in rats by aortic banding, and ventricular function was measured by means of the isolated, isovolumic heart perfusion technique. The hypertrophied hearts had a greater susceptibility to ischemic injury than nonhypertrophied control hearts, as manifested by a greater degree of diastolic contracture during the recovery period after 30 minutes of ischemic arrest at 37 degrees C. Hypothermia without cardioplegia during a 2-hour arrest did not completely preserve diastolic function in the hypertrophied hearts, but cardioplegia combined with hypothermia completely protected the hypertrophied hearts against 2 hours of ischemia. The results suggest a need for both hypothermic and cardioplegic preservation techniques in patients with myocardial hypertrophy who have cardiac surgical procedures requiring a significant period of myocardial ischemia.
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PMID:Increased injury of hypertrophied myocardium with ischemic arrest: preservation with hypothermia and cardioplegia. 293 42

The authors relate their experience concerning the surgical correction of congenital coronary fistula. Between May 1971 and June 1986, 9 patients (4 boys and 5 girls) aged from 17 days to 49 years were operated upon at the Division of Cardiac Surgery of Bergamo (Ospedali Riuniti). All the patients, except three who were asymptomatic, showed early cardiac failure or dyspnoea on effort and angina in the elderly. At the physical examination a continuous murmur was heard in 8 cases; the chest x-ray showed significant cardiomegaly and on the electrocardiogram a right/left ventricular hypertrophy pattern was detected in 5 patients. All the patients underwent cardiac catheterization and a coronary angiography. The left-to-right shunt ranged from 60% to 250% of the cardiac output. The anomalous communication affected the right coronary artery in 7 cases and the left in 2, opening into the right atrium in 4 patients, into the right ventricle in 3 and into the pulmonary artery in 2. All patients but one, in whom division and suture were the only necessary procedures, underwent correction by means conventional cardiopulmonary by-pass with moderate hypothermia. In 3 cases closure through the coronary artery was preferred, in 1 through the right ventricle and in 2 transpulmonary. There was only 1 late death which occurred in a 3 year-old patient due to renal failure. After a mean follow-up of 6 years, 7 patients are to be asymptomatic while 1 patient had to be reoperated for a significant residual shunt.
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PMID:[Congenital coronary fistulae. Comments on 9 surgical cases]. 297 Apr 13

The quality of myocardial protection during cardiac arrest in cardiac operations was investigated in 310 patients. Eighty patients underwent aortic valve replacement and 230 had coronary artery bypass grafting. Four different cardioplegic solutions (Kirsch, Bretschneider, St. Thomas' Hospital, and Hamburg) and the method of induced fibrillation were tested by ultrastructural analysis of the degree of ischemic injury at the end of the cardiac arrest period. Hypothermia was identical in all five groups. In this study, subendocardial and subepicardial needle biopsies were evaluated by a standardized scoring system. Chemical cardioplegia produced mainly moderate ultrastructural injury independent of the time of ischemia. Kirsch cardioplegia and the intermittent fibrillation procedure produced ischemic injury of greater and unpredictable severity. Only with Kirsch cardioplegia was a correlation observed between the duration of intraoperative arrest and the degree of injury, which is indicative of a lack of myocardial protection. The tolerance to ischemia was significantly better in patients undergoing bypass grafting than in those with aortic valve disease and therefore longstanding hypertrophy. In conclusion, the Bretschneider, St. Thomas' Hospital, and Hamburg solutions provide satisfactory myocardial protection but are not able to completely prevent myocardial ischemic injury. Kirsch cardioplegia and the intermittent fibrillation procedure provide insufficient myocardial protection. Patients with left ventricular hypertrophy are at a greater risk during cardiac operations than patients undergoing coronary bypass operations.
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PMID:Ultrastructural study comparing the efficacy of five different methods of intraoperative myocardial protection in the human heart. 308 35


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