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Biomedical subjects

D Brodaty

Publications and source records attributed to D Brodaty.

At least 19 recordsLinked to original sources
PubMed1991

Cold cerebroplegia. A new technique of cerebral protection during operations on the transverse aortic arch.

Profound hypothermia associated with circulatory arrest is the commonest method of cerebral protection during operations on the aortic arch. This technique allows a limited time to perform the aortic repair, however. It also necessitates prolonged cardiopulmonary bypass to rewarm the patient. This may be the cause of coagulation disorders or infection. Selective perfusion of the carotid arteries can also be used. When the perfusion is derived from the main arterial line, however, the repair of the aorta requires that the vessel be crossclamped, and cannot be performed in an "open, bloodless" manner. To avoid the disadvantages of both techniques, we have developed a new technique of cerebral protection. After a regular cardiopulmonary bypass has been established, the carotid arteries are cannulated and perfused with blood cooled at 6 degrees to 12 degrees C, through a separate heat exchanger, while the core temperature is maintained at moderate hypothermia (25 degrees to 28 degrees C, rectal). To perform the "open" distal repair, the cardiopulmonary bypass is discontinued while the carotid perfusion is maintained (250 to 350 ml/min). When the distal repair is completed, cardiopulmonary bypass is resumed and the carotid perfusion is discontinued. Between 1984 and June 1989, 54 patients (mean age 55 years) were operated on with this method (45 elective operations, 9 emergency procedures). Mean duration of cardiopulmonary bypass was 121 minutes (65 to 248), and mean duration of circulatory arrest was 22 minutes (10 to 51). The electroencephalogram, routinely recorded, showed return of the cerebral activity after a mean time of 12 minutes and normal activity after a mean time of 66 minutes. There was no intraoperative death. Hospital mortality rate was 13% (7/54). One death was related to neurologic disorders. All patients but one awakened normally within 8 hours after operation. Two patients (4.3%) experienced a transient neurologic episode (lateral hemianopia) 9 and 11 days postoperatively. There was no hemorrhagic complication (24-hour average blood loss: 840 +/- 540 ml). In our experience the technique of "cold cerebroplegia" has been demonstrated to provide excellent cerebral protection. It requires no prolonged cardiopulmonary bypass and does not limit the time necessary to perform the aortic repair. It may be considered as a safe alternative to profound hypothermia associated with circulatory arrest.

Adult↗
PubMed1990

Repeated surgery for recurrent dissection of the aorta.

Emergency surgery of acute dissection of the ascending aorta is generally a palliative procedure aimed at preventing the vessel from rupturing into the pericardium. Evolving dissecting aneurysm or recurrence of the dissection process is, therefore, a common complication and may lead to reoperation or death. Between January 1970 and December 1988, 133 patients were operated upon for acute dissection of the ascending aorta. During the same period, 22 patients underwent 26 reoperations for recurrent or evolving dissection. Eleven (50%) patients had Marfan's syndrome. Thirteen patients had been operated upon previously in our institution and 8 had been operated upon elsewhere. In 10 patients, the intimal tear had not been resected during the first operation. Operative procedures varied according to the pathoanatomical features and consisted generally of an extended resection of the aortic arch. Eight reoperations were performed as emergencies and 18 were performed electively. Hospital mortality rate was 18% (4/22). Late follow-up ranged from 3 to 153 months (mean: 55 months) for a cumulative follow-up of 998 months. Late mortality was 27% (5/18) for a linearized rate of 6% pt/yr. The actuarial risk of reoperations is 13.7% +/- 7% and 21% +/- 11% at 5 and 10 years, respectively. Marfan's syndrome and persistence of the primary intimal tear are considered the main risk factors of reoperation, while emergency and thoraco-abdominal replacement are the main risk factors at reoperation.

Adult↗
PubMed1989

[Surgical treatment of chronic pulmonary embolism using thromboembolectomy under extracorporeal circulation and deep hypothermia--a new approach route. 3 cases].

The authors, who have successfully performed thrombectomy of the pulmonary artery under extracorporeal circulation and deep hypothermia in three patients, wish to draw attention to the principal factors of success. The decision to operate, as accepted by most surgeons, rests on the patient's functional status (stage III or IV) and on the presence of a systolic pulmonary arterial pressure exceeding 50 mmHg. Deep hypothermia combined with circulatory arrest seems to be the best method, as it improves visual control, thereby avoiding damage to the endothelium or fracture of the distal thrombi during thrombectomy. Finally, a new approach route (severing of the superior pulmonary vein, opening of the pulmonary artery and use of Volmar-Sisteron strippers) makes it possible to remove the entire thrombus, thus obtaining an almost normal pressure in the pulmonary artery. In all three patients, the complications that are mostly due to intrabronchial haemorrhage by disruption of the endothelium, fracture of the distal thrombus or pulmonary artery contusion were avoided.

Adult↗
PubMed1988

Surgery of aortic stenosis and lesions of the ascending aorta.

Between 1978 and 1986, 442 aortic valvular replacements were performed for chronic calcified aortic stenosis. In 11 patients (2.5%, seven men and four women) replacement of the ascending aorta was associated with the valvular replacement, because of: seven supra-coronary aneurysms, two aneurysms involving the Valsalva sinuses, and two acute dissections of the ascending aorta. The repair of the ascending aorta consisted in inserting: one patch on one Valsalva sinus, seven supra coronary Dacron prostheses, three valved conduits (according to the Bentall technique). One patient died postoperatively (9%).

Adult↗
PubMed1988

[Replacement of the ascending aorta with reimplantation of coronary vessels. Apropos of 81 cases].

Between 1973 and 1985, 81 patients underwent Bentall's operation. 90 p. 100 of the patients had cystic medionecrosis, but only 24 showed signs of Marfan's syndrome. It must be noted that 12 patients were reoperation cases, 18 were operated upon in an emergency for tamponade (stage V) on acute dissection, and 7 had lesions that involved the aortic arch. The operative procedure was that described by Bentall; Cabrol's modification was used in only 26 patients. The most recent improvements concerned myocardial and (in case of aortic involvement) cerebral protection with an autonomous perfusion of blood at very low temperature. Mortality was low in patients with annulo-aortic ectasia (1 death in 53 cases; 1.8 p. 100) and rose to 34.5 p. 100 (33.3 p. 100 in reoperation cases) in patients with chronic dissection. Evaluation of mortality by stage showed virtually no risk in stages I and II, whereas 4 of the 9 stage IV patients died within the first post-operative month. Late mortality with a mean follow-up of 4 years was 14.2 p. 100; 2 of the 10 deaths were accidental, and 4 of the remaining 8 deaths were due to the anticoagulant therapy (death was precipitated in 2 cases by the presence of a cerebral aneurysm). No case of systemic embolism was observed, and the authors raise the question of whether long-term anticoagulant therapy should be abandoned. None of the patients who underwent Bentall's operation were reoperated upon, whereas 7 out of the 23 patients who had had supracoronary aortic replacement before 1976 had been reoperated upon within a few years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Replacement of the transverse aortic arch during emergency operations for type A acute aortic dissection. Report of 26 cases.

In type A aortic dissection, the intimal disruption is located on or extends to the transverse arch in about 20% of patients. Replacement of the arch may then be necessary to avoid leaving an unresected, acutely dissected aorta and to prevent bleeding, progression of aneurysm, rupture, and ultimately reoperation or death. From 1970 to September 1987, 119 patients were operated on for type A acute dissection. Starting in January 1977, gelatin-resorcin-formaldehyde biologic glue was used in 91 patients to reinforce the dissected tissues at the suture sites. Among these 119 patients, 26 (ages 32 to 76 years) underwent replacement of the transverse aortic arch in addition to replacement of the ascending aorta. In 20 patients cerebral protection was achieved by profound hypothermia (16 degrees to 20 degrees C) associated with circulatory arrest (15 to 40 minutes, mean 27 minutes) during the distal anastomosis. In six patients the carotid arteries were selectively perfused with cold blood (6 degrees C) during moderate core hypothermia (28 degrees C) while cardiopulmonary bypass was discontinued (19 to 34 minutes, mean 25 minutes) to allow the prosthesis to be sutured without the distal aorta being cross-clamped. Moderate hypothermia avoided the long rewarming time necessitated by profound hypothermia. The hospital mortality rate was 34% (9/26). Two of the 20 patients subjected to profound hypothermia and circulatory arrest died during the operation and seven patients died of postoperative complications. No deaths or major complication were observed in the other six patients. Follow-up of the 17 survivors ranges from 3 to 90 months (mean 39). One patient died 6 months after the operation of cerebral hemorrhage. One patient is disabled by neurologic sequelae. Fifteen patients are in good clinical condition (New York Heart Association class I or II). Postoperative aortograms in 12 patients, and computed tomographic scans in all, have shown a stable repair of the transverse arch in all survivors but a persisting dissection of the descending aorta in 11 (70%). Growing experience and improving results in emergency operations for type A aortic dissection have led us to extend the replacement of the aorta to the transverse arch whenever necessary. The gelatin-resorcin-formaldehyde glue has proved to be an efficient adjunct. The best cerebral protection was obtained in our experience by carotid perfusion with cold blood during circulatory arrest at moderate core hypothermia.

Acute Disease↗
PubMed1987

[Emergency surgical repair of acute aortic arch dissection. Apropos of 14 cases].

Among 70 patients operated upon for acute dissection of the ascending aorta between 1977 and 1984, 14 (age range 40-72 years) benefited from emergency aortic arch repair motivated by the presence in, or extension to, this segment of the portal of entry, or by lesions of the supra-aortic main vessels. The operation was performed under cardiopulmonary bypass in all cases. Cerebral protection was ensured in 9 patients by deep hypothermia alone or with circulatory arrest for a mean period of 5 minutes (7 cases), and in 5 patients by continuous brain perfusion (carotid blood flow 4 ml/kg/min; perfusion pressure 70 mmHg). Repair consisted of ascending aorta replacement combined with gluing of the arch whenever possible, or bevelled resection in the concavity of the arch, or complete aortic arch replacement with reimplantation of the cervico-cerebral vessels when necessary. In every case the gelatin-resorcin-formalin glue was used to reinforce the aortic wall or the areas with sutures. Operative mortality was nil. Hospital mortality was 28.5%. In patients operated upon under deep hypothermia alone or associated with circulatory arrest the main complications were neurological (4 cases) and respiratory (3 cases) disorders; these were responsible for the death of 3 patients. A fourth patient died of mediastinitis. No neurological or respiratory complication occurred in patients who had brain perfusion. The mean follow-up period was 37 months (range 7-84 months). Late mortality was nil. All but one patient (sequelae of paraplegia) are in excellent clinical condition. Post-operative angiography alone or combined with computerized tomography showed satisfactory blood distribution in all cases and no aneurysm formation on the dissected aorta despite a persistent false lumen.

Acute Disease↗
PubMed1987

[Clinical experience with the Saint Jude prosthesis. Results over a period of 7 years].

Between January, 1979 and December, 1985, 193 Saint Jude medical valves (SJM) were implanted in 165 patients (74 male, 91 female) aged from 14 to 78 years (mean age: 49 years). 101 patients underwent aortic valve replacement, 36 had mitral valve replacement and 21 had multiple valve replacement. Fitting with an SJM prosthesis was a primary emergency operation for 15 patients (9%) and a reoperation for 49 patients (31%). A concomitant surgical procedure was carried out in 39 patients (24%). The overall peri-operative mortality rate was 9% (15 patients), this figure falling to 5% (6/112 patients) when emergency surgery and reoperations are excluded. No patient was lost sight of. Mean follow-up was 37 +/- 3 months (range: 4 to 84 months), for a total duration of 413 years/patient. Five patients died of heart disease during the follow-up period, representing a mortality rate of 1.2% per year/patient. The actual survival rate was calculated as 90% at 1 year and 83% at 7 years. During that period 7 thromboembolic accidents occurred among 5 patients (actual rate: 1.7 accident per 100 years/patient). Two mechanical valve desinsertions requiring reoperation were recorded. Altogether, the actuarial rate of patients without any post-operative complication was 88% at 1 year and 65% at 7 years. Functional improvement was dramatic since 94% of survivors are now in class I or II, whilst 67% of patients were in class III or IV prior to surgery. It may be concluded that the mid-term

Actuarial Analysis↗
PubMed1986

[Aneurysm of the aortic arch. Surgical therapy. 60 cases].

Sixty patients with aortic arch aneurysm have been operated upon at the Foch Medico-Surgical Centre between 1964 and 1984. This period can be subdivided into: January, 1964 to December, 1975 (24 cases) and January, 1976 to April, 1984 (36 cases). The technique used (closure by patch or segmental replacement prosthesis) depended on the type of lesion encountered. In most cases, the cardiopulmonary bypass was between the femoral artery and the right atrium. After experimenting with different methods, we now protect the brain by selective cold blood carotid perfusion, using independent circuit and heat-exchanger. Operative mortality was 12% in series I (1964-1975) and 0% in series II (1975-1984) patients. Hospital mortality was 25% in series I and 13% in series II patients. The improvements obtained during the last few years, using cold blood carotid perfusion and circulatory arrest in the lower half of the body, have made it possible to perform open distal anastomoses. This method ensures excellent brain protection and short cardiopulmonary bypass period.

Adult↗
PubMed1986

Changes in intrathoracic pressures induced by positive end-expiratory pressure ventilation after cardiac surgical procedures.

The consequences of controlled ventilation with positive end-expiratory pressure (PEEP) were studied, after cardiac surgical procedures, in two groups of patients supposed to have different lung and chest wall mechanical properties. The first group included 6 patients who had undergone coronary artery graft surgical procedures (CGS). The second group included 5 patients who had undergone a mitral valve replacement (MVR). Postoperatively, static lung and chest wall compliance was measured by stepwise inflation and deflation of the thorax. Esophageal, pericardial, and pleural pressures were then measured, and cardiac output was determined while PEEP was increased from 0 to 20 cm H2O. Lung and chest wall compliance values sharply decreased in MVR patients. This accounts for the lower values for pleural and pericardial pressures in this group than in the CGS patient group, but the transmission of airway pressure was identical in the two groups when PEEP was increased. The decrease in cardiac output induced by PEEP was similar in the two groups. The results suggest that the opposing influences of lung and chest wall compliance on airway pressure transmission could at least partly explain the hemodynamic effects of PEEP in patients in whom the mechanical properties of the lung and thorax are impaired. PEEP ventilation should be used cautiously in patients suspected of having thoracic rigidity.

Cardiac Output↗
PubMed1985

Circulatory responses to thiopentone and tracheal intubation in patients with coronary artery disease. Effects of pretreatment with labetalol.

The haemodynamic responses to induction and tracheal intubation have been studied in patients with coronary artery disease randomly assigned to a labetalol pretreatment group (n = 14) or to a placebo group (n = 16). Twelve hour before operation, treated patients received a bolus dose of labetalol 0.5 mg kg-1 followed by a constant infusion of 0.1 mg kg-1 h-1 i.v. Anaesthesia was induced with thiopentone and phenoperidine, and intubation performed following the administration of suxamethonium. At intubation, the changes in heart rate (P less than 0.01), mean arterial pressure (P less than 0.05) and rate-pressure product (P less than 0.01) were significantly smaller in the labetalol group compared with the placebo group. Labetalol pretreatment appears satisfactory and may be useful in patients with coronary artery disease who have a normal left ventricular ejection fraction.

Anesthesia, General↗
PubMed1985

Pharmacokinetics of phenoperidine in patients undergoing cardiopulmonary bypass.

Phenoperidine concentrations were studied, using radioimmunoassay, in five patients submitted to coronary artery bypass graft surgery. Administration of phenoperidine consisted of a 5-mg bolus dose followed by constant infusion of 5 mg h-1. Before cardiopulmonary bypass, phenoperidine concentrations were stable in an individual patient, but there was a large scatter between patients. The concentrations decreased immediately following the start of the bypass, but this decrease was short. During cardiopulmonary bypass, the phenoperidine concentrations increased progressively and were greater at the end of the bypass than before it. The increase in concentration continued following the discontinuation of bypass. The ratios of change of the observed results were in accord with a theoretical evaluation, although the observed concentrations were all greater than those calculated, except at one point. This difference in phenoperidine concentration is probably related to an alteration of liver plasma flow. Haemodilution as a result of the priming of the cardiopulmonary bypass circuit played only a transient role.

Adult↗
PubMed1985

[Repeated valvular replacements].

After more than two decades of cardiac valve replacement surgery, the number of reoperations has increased and third or even fourth replacements are no longer rare occurrences. Of the 2072 valves prostheses implanted at the Hôpital Foch between 1970 and December 1984, 134 (6.4%) have been changed at least once and 27 prostheses (1.3%) have been replaced three or more times in 23 patients. Eighteen patients were operated on three times and 5 patients 4 times, a total of 73 operations. Ten patients had aortic valve prostheses, 7 had mitral valve prostheses and 6 had double aortic and mitral valve prostheses. The technical difficulties due to previous cardiac surgery were not great or easily surmounted as every procedure was performed by a median sternotomy and only 2 out of 50 required cannulation of the femoral vessels for cardiopulmonary bypass. The repair itself consisted of simple valve replacement in 3 out of 4 cases (30 single and 3 double valve replacements, 3 valve reinsertions). The other operations required more complex techniques such as remodelling of the ring of insertion or the use of a valved tube. None of the patients died in the operating theatre. However, 3 patients died during the hospital period (13%) and there were 2 late deaths (10%) and 1 patient (5%) was lost to follow-up. The 17 survivors were followed up for 3 to 148 months (average 42 months). Half the patients are now in functional Classes I or II of the NYHA classification. These results show that repeated valve replacement has an acceptable operative risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1984

[Dissection of the ascending aorta after aortic valve replacement].

From October, 1969 to December, 1982, 1117 aortic valve replacements were performed at the Foch Medico-Surgical Centre. Five of these operations (0.4%) were followed, within 6 months to 6 years (mean 37 months), by acute dissection of the whole ascending aorta with a varying degree of extension further down. Such accidents raise problems of aetiology, diagnosis, treatment and possibly prevention. All 5 patients had an emergency operation with prosthetic replacement of the ascending aorta; in some cases the 2 cylinders were glued to the distal and proximal aortic stumps. The other forms of treatment were related to the lesions encountered. All patients survived and underwent follow-up angiography after 6 months to 5 1/2 years. Lesions of cystic necrosis of the media were regularly found at histology. In every case during the first operation the surgeon reported that the aorta was dilated or particularly fragile. The question therefore arises as to whether ascending aortas that are fragile and of more than 5 cm in diameter should be systematically replaced.

Adult↗
PubMed1984

[Destruction of the bundle of His with the neodymium-YAG laser. Preliminary experimental study].

Experiments with a new technique for His bundle interruption were performed on 10 dogs. The atrioventricular node-His bundle track was destroyed by means of a neodymium-yttrium-aluminium-garnet laser (Nd-YAG laser) used in continuous emission at 35 watts. The operation was conducted under simple clamping of the vena cava for a mean period of 1 minute 30 seconds, and 30 seconds were required for destruction of the His bundle. An atrio-ventricular block was obtained immediately in all dogs and persisted for more than 3 weeks. No accident was recorded. The Nd-YAG laser therefore appears to be a reliable technique and could be used for surgical treatment of arrhythmias.

Aluminum↗
PubMed1979

[Conduction disorders after aortic valve replacement. Apropos of 200 cases].

The following points become apparent after the study of 200 cases of aortic valve replacement:--Conduction defects are very common after this type of surgery, affecting one in three patients in this series;--Above all, the frequency of conduction defects of the left bundle branch (2/3 cases) must be underlined. They are much more common than complete atrioventricular block, bifascicular block or isolated right bundle branch block;--Diagnosed immediately after operation in almost all cases, regression is common (50%) especially of left anterior hemiblock;--The long term prognosis is good. There was no long or short term mortality due to this cause in this series;--Apart from traumatic lesions which are difficult to avoid when the aortic orifice is calcified, ischaemia of the conduction pathways due to insufficient myocardial protection probably plays a role in the aetiology of these conduction defects.

Aortic Valve↗