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Biomedical subjects

L Levinsky

Publications and source records attributed to L Levinsky.

At least 19 recordsLinked to original sources

Safety precautions in the management of patients with pacemakers when electrocautery operations are performed.

The hazards related to ten patients who underwent 11 urologic surgical procedures during a 36 month period were taken into consideration. Electrocautery was used in all instances and there were no complications. All of the pacemakers were preset for ventricular pacing and sensing inhibited or multiprogrammable and were reprogrammed during the operation to ventricular pacing fixed rate mode or magnet mode, with very satisfactory outcome. To avoid life-threatening situations arising from pacemaker inhibition or ventricular fibrillation during cautery for transuretheral resection, three basic factors were considered: 1, appropriate type of pacemaker; 2, the proper grounding of all medical electronic equipment used during the procedure, and 3, the directing of the complete flow of the electrocautery circuits substantially below the level of the pacemaker unit.

Accident Prevention↗

Dissecting aortic aneurysm in pregnant women without Marfan disease.

Dissection of the young women without Marfan disease is related, in most instances, to pregnancy. The structural changes in the arterial wall that occur during pregnancy may predispose women to this complication of pregnancy. In this study, two young women, who had none of the characteristics of Marfan's syndrome, were operated upon for dissection of the ascending aorta. The first patient was in the 35th week of gestation and a cesarean section was performed prior to replacement of the ascending aorta. In the second patient, diagnosis of dissection and severe aortic regurgitation occurred in the postpartum period. Knowledge of this albeit relatively rare complication of pregnancy may assist the clinician in diagnosing and referring patients early for surgical treatment that, in most instances, may save the lives of both mother and fetus.

Acute Disease↗

Cardiovascular effects of UD-CG 212 CL, a metabolite of pimobendan, in anaesthetized pigs.

Systemic and regional haemodynamic effects of UD-CG 212 CL (0.5-16 micrograms X kg-1 X min-1), the major metabolite of the vasodilator and cardiotonic drug pimobendan, were studied in anaesthetized pigs. The drug caused a dose-dependent decrease in left ventricular (LV) end-diastolic and arterial blood pressures while it increased systemic vascular conductance, heart rate and maxLVdP/dt. The decrease in LV end-diastolic pressure was observed at lower plasma concentrations than the increase in systemic vascular conductance. Cardiac output tended to decrease but statistical significance was achieved only with the highest concentration. These effects of UD-CG 212 CL were not altered by the blockade of beta-adrenoceptors with propranolol. The vasodilator action of UD-CG 212 CL was noticed in several organs but the effects were relatively more marked (in decreasing order of magnitude) in the adrenals, kidneys, gastrointestinal tract, brain and LV epicardium. Since both arterial pressure and cardiac output decreased, the blood flow increased significantly only in the adrenals and decreased moderately in the spleen, LV endocardium and skeletal muscles. The effects of UD-CG 212 CL on the renal and skeletal muscle haemodynamics were different from those of pimobendan, which causes vasodilatation in the skeletal muscles but not in the kidneys. The results of this study show that, like the parent compound pimobendan, UD-CG 212 CL has independent cardiotonic and vasodilator actions; the latter being more pronounced on the venous side. However, the contribution of this metabolite to the overall pharmacological activity of pimobendan appears to be limited.

Adrenergic beta-Antagonists↗

Acute hepatic failure after open-heart surgery in children.

Acute hepatic failure (AHF) combined with acute renal failure (ARF) is a well-known complication of open-heart surgery in adults. The occurrence of this complication in two children after open-heart surgery for correction of congenital heart disease is reported. Hypotension occurred during the operation and was treated by catecholamine vasopressors. AHF set in during the postoperative course; it was manifested by impaired consciousness, hypoglycemia, hyperbilirubinemia, hyperammonemia, elevated liver enzymes and prolongation of the prothrombin time with failure of hemostasis. ARF also developed in both children. One of the patients survived the acute episode of hepatic failure. The importance of early diagnosis, routine close monitoring, and appropriate selection of vasopressors is emphasized.

Acute Disease↗

Systemic haemodynamic actions of pimobendan (UD-CG 115 BS) and its O-demethylmetabolite UD-CG 212 Cl in the conscious pig.

The cardiovascular effects of the pyridazinone-derivatives pimobendan and its O-demethylmetabolite UD-CG 212 Cl (2-(4-hydroxy-phenyl)-5-(5-methyl-3-oxo-4,5-dihydro-2H-6-pyridazinyl) benzimidazole HCl) were studied in conscious pigs, employing consecutive intravenous 10 min infusions of 10, 25, 50 and 100 micrograms kg-1 min-1 and 2, 4 and 8 micrograms kg-1 min-1 respectively. Pimobendan caused dose-dependent increases in LVdP/dtmax (up to 115%) and heart rate (up to 30%), while cardiac output was slightly elevated (up to 15%) and stroke volume decreased by 12%. Left ventricular end-diastolic pressure decreased in a dose-related manner from 8.7 +/- 1.0 mmHg to 2.7 +/- 1.7 mmHg. Mean arterial blood pressure was not significantly affected because systemic vascular resistance decreased dose-dependently up to 15%. After beta-adrenoceptor blockade, the pimobendan-induced increases in heart rate and cardiac output were attenuated and the increase in LVdP/dtmax almost abolished. The responses of left ventricular end-diastolic and mean arterial blood pressure, systemic vascular resistance and stroke volume were not modified. UD-CG 212 Cl caused dose-related increases in LVdP/dtmax (up to 100%) and heart rate (up to 25%). Cardiac output was minimally elevated (up to 8%) as stroke volume decreased dose-dependently up to 15%. As systemic vascular resistance decreased up to 12%, mean arterial blood pressure was slightly reduced (5%). Left ventricular end-diastolic blood pressure decreased dose-dependently from 9.0 +/- 0.8 mmHg to 3.8 +/- 1.3 mmHg. After beta-adrenoceptor blockade, the UD-CG 212 Cl-induced increases in heart rate and LVdP/dtmax were attenuated and almost abolished and amounted up to 15% and 20%, respectively. The responses of the other systemic haemodynamic parameters were not significantly modified. We conclude that pimobendan and UD-CG 212 Cl are compounds with marked positive inotropic and venodilator properties in the conscious pig. The attenuation of the inotropic effects by pretreatment with propranolol strongly suggests that, in the conscious pig, the beta-adrenergic system is significantly involved in the positive inotropic actions. The lack of effect of beta-adrenoceptor blockade on the vasodilator responses to both compounds suggest a mechanism not related to beta-adrenergic activity.

Animals↗

Closed pericardial drainage for relief of pericardial tamponade.

The method of continuous catheter drainage for pericardial tamponade as used in 108 patients is described. The efficacy of this procedure in relieving tamponade resulting from a variety of diseases is demonstrated. Blood clot in the pericardium probably constitutes a contraindication to catheter drainage.

Cardiac Catheterization↗

Repair of coarctation of the aorta in the first three months of life.

Coarctation of the aorta was surgically treated in 28 infants (16 male, 12 female) aged 2 days-3 months, with 19 younger than 1 month. Body weight at operation was 1.6-4.2 (mean 2.8) kg. 3 infants had coarctation alone, 10 had a wide patent ductus arteriosus as the only associated anomaly and 15 had a variety of other anomalies. Resection with end-to-end anastomosis was performed in only one case, while 21 underwent subclavian flap aortoplasty and six patch graft aortoplasty. Additional procedures were banding of the pulmonary artery in five cases and open aortic commissurotomy in one case. The early mortality was 10.7% (3 infants) and three more died later. Further cardiac surgery was subsequently performed on four of the infants. Of the 22 survivors, two had significant recurrence of coarctation which, however, was successfully corrected in one case. The blood pressure was within normal limits in all survivors, except those with recoarctation.

Aortic Coarctation↗

Use of the Shaw Scalpel in pacemaker operations.

Pacemaker carriers are at risk when undergoing operations involving the use of diathermy. The Shaw Scalpel utilizes a method by which the cutting edge of the blade is heated to a selected temperature that seals blood vessels as they are cut. No electrical currents are passed to or through the patient and there is no sparking or electrical arcing to the tissue. This apparatus was used as the sole method of thermal coagulation in 20 patients undergoing replacement of pacemaker batteries.

Diathermy↗

Pregnancy after valve replacement with porcine xenograft prosthesis.

The course of 22 pregnancies in 11 women undergoing heart valve replacement with a porcine xenograft is reported. All of the pregnancies treated with warfarin were interrupted by induced abortion. Of the 11 pregnancies treated with dipyridamole which were not interrupted by induced abortion, fetal wastage occurred in five. There was no fetal wastage among three patients who were not treated by any kind of anticoagulant. A review of the literature revealed that fetal complications among patients with the mechanical prosthetic valve are significantly higher compared with patients with bioprosthetic valves. There was no maternal hemorrhagic or thromboembolic event in patients with bioprosthetic valves. Delivery after porcine xenograft insertion is safe provided that the patient is in good cardiac condition and does not require warfarin treatment.

Abortion, Induced↗

Calcification of a porcine valve xenograft during pregnancy--a case report and review of the literature.

A 20-year-old woman required urgent replacement of a calcified prosthetic mitral porcine xenograft with a mechanical one during the 32nd week of pregnancy. Five weeks later the patient delivered a normal child. Following delivery the patient refused oral anticoagulant treatment and 7 months later she underwent emergency removal of a prosthetic valve thrombus. Six months later, still refusing anticoagulant treatment, she died of cerebral embolization. We suggest that the replacement of a degenerated biologic valve with another biologic valve should be considered in patients who refuse anticoagulant treatment and that patients with prosthetic xenografts should be kept under close medical follow-up, including echocardiography because of possible accelerated xenograft failure during and/or following pregnancy.

Adolescent↗

Myocardial protection in infant open heart surgery.

Myocardial protection was evaluated in 2 groups of 5 infants each undergoing correction of either tetralogy of Fallot (TOF) or subcristal ventricular septal defect (VSD). In group A, profound hypothermia and total circulatory arrest (PHTCA) was utilized. In group B, profound hypothermia and total circulatory arrest combined with potassium cardioplegia (PHTCA + K) was the method of protection used. The analysis was carried out by sequential measurements of clinical, electrocardiographic, enzymatic (CK-MB) and ultrastructural parameters. There were no operative deaths. One infant had a second operation for recurrent VSD. The average anoxic time was 35.4 min in group A (PHTCA) and 32.6 min in group B (PHTCA + K). Analysis of our data demonstrated that when potassium cardioplegia was added to PHTCA, there was less intraoperative myocardial damage according to physiological, ultrastructural and biochemical parameters than when profound hypothermia and total circulatory arrest was applied alone.

Creatine Kinase↗

Coarctation of the aorta in infancy.

Twenty-five infants under 1 year of age (mean weight 3.4 kg) underwent repair of coarctation of the aorta between the years 1965 and 1982. Three patients had coarctation only, three had coarctation with patent ductus arteriosus (PDA), and 19 had associated intracardiac anomalies. Eleven patients underwent resection of the aorta and end-to-end anastomosis. Eight had subclavian flap arterioplasty, five had patch graft arterioplasty, and one had subclavian-to-aortic anastomosis. Additional procedures were performed on seven patients: banding of the pulmonary artery on one, repair of total anomalous pulmonary venous drainage on one, mitral valve replacement on one, aortic valvotomy on one, and aortic valvotomy plus pulmonary artery banding on one. Twenty-one survived the operation. All patients who died had associated intracardiac anomalies. The 21 survivors have been followed from 3 months to 13 years, with three late deaths that were associated with intracardiac anomalies. Five of the survivors underwent additional second operations: one had repair of the re-coarctation, one had replacement of the prosthetic mitral valve, one had aortic valvotomy, and two had pulmonary artery debanding and closure of a ventricular septal defect. Two of the 18 surviving patients have mild hypertension associated with a residual gradient. The others are in good health.

Journal Article↗

Vascular rings: management and a proposed nomenclature.

Over 18 years, 33 patients with congenital vascular rings underwent surgical treatment. All patients had full recovery except 1 who died late. At the one-month follow-up, 66.7% had complete relief of the presenting symptoms. Important aspects of the clinical picture, diagnostic methods, and treatment are presented. A coded nomenclature is proposed; we believe it to be accurate, inclusive, easy to remember, and readily referable to the embryological origin.

Aorta, Thoracic↗

Reconstruction of the new atrial septum in the Senning operation. New technique.

A new technique incorporating the left atrial appendage for the reconstruction of the new atrial septum is described as a modification of the original Senning operation for transposition of the great arteries. In reconstruction of the atrial septal flap, the balloon septostomy defect is closed by approximating the inverted left atrial appendage to the anterior margin of the flap. This technique completely eliminates the necessity for foreign material in the repair of the new atrial septum of the Senning operation and has been used in 21 patients with good results.

Cineangiography↗