Nifedipine as an adjunct to St. Thomas' Hospital cardioplegia. A double-blind, placebo-controlled, randomized clinical trial.

The cardioprotective effect of the addition of the slow calcium-channel blocker nifedipine to cardioplegic solution was tested in two double-blind placebo controlled randomized studies. The first study included 24 patients undergoing aortic-coronary bypass grafting, and the second included 24 patients undergoing aortic valve replacement. Nifedipine at a dose of 200 micrograms/L or placebo was added to St. Thomas' Hospital cardioplegic solution. The following markers of ischemia were used: adenosine triphosphate and its catabolites, creatine phosphate and inorganic phosphate, determined in transmural left ventricular biopsy specimens taken before, at the end of, and after aortic cross-clamping; hemodynamic recovery 15 minutes after cessation of cardiopulmonary bypass; clinical outcome in terms of the incidence of arrhythmias, low cardiac output, positive inotropic support immediately after operation, and follow-up at 15 months. The main difference between the two studies was that myocardial temperature during cross-clamping remained constant at 14 degrees C in coronary bypass grafting but increased to 25 degrees C in valve operations despite the application of the same amounts of cardioplegic solutions. This lower temperature resulted in better preservation of high-energy phosphates in coronary bypass operations as compared to the placebo group having valve replacement operations. According to analysis of variance, a drug effect could be demonstrated only in the aortic valve replacement study: Accumulation of breakdown products of the adenine nucleotide pool was less in the nifedipine group than in the placebo group (p less than 0.05). Adenosine triphosphate decreased only to 84% in the nifedipine group and to 72% in the placebo group. Despite this adenosine triphosphate-sparing effect, weaning from cardiopulmonary bypass was more difficult in the nifedipine group. Left ventricular stroke work index 15 minutes after bypass was decreased to 72% of the prebypass value in the nifedipine group (t test, p less than 0.01) and only to 86% in the placebo group (p = NS). In contrast, after the patients were admitted to the intensive care unit, the incidence of low cardiac output tended to be lower in the nifedipine group than in the placebo group: 33% versus 58% (p = NS). In conclusion, ischemia-induced degradation of nucleotides as it occurs when myocardial cooling is inadequate can be prevented by the addition of nifedipine to the St. Thomas' Hospital cardioplegic solution. This effect, however, is not associated with an improved clinical outcome.

Profile of creatine phosphokinase (CK) and its isoenzyme MB (CK-MB) during corrective procedures of congenital cyanotic heart disease.

This study investigates the influence of inadequate oxygen supply on CK and CK-MB release rate in congenital cyanotic heart disease in fourteen patients. Eleven patients had Tetralogy of Fallot and 3 Transposition of great vessels. Their age ranged between 10 days and 10 years (mean 50.48 +/- 31.82 months). The corrective repair was carried out under CPB with systemic hypothermia (20 degrees-25 degrees C) and intermittent St. Thomas Cardioplegia perfusion in the aortic root until the septal temperature was below 16 degrees C. Three blood samples were taken before, during and 10 minutes after CPB to quantitate the CK and CK-MB. In 6 cases of Fallot, two simultaneous biopsies, one from the right and another from the left ventricular walls were taken at the end of the 10 first minutes of reperfusion to evaluate the ATP, CP and glycogen contents. CK and CK-MB levels showed an increasing evolution; the CK-MB per cent increased sharply after aortic clamp release and then fell abruptly to low values at the 10th minute after CPB arrest. Comparative evaluation between the 3 values for C K showed significant differences (P less than 0.001) in all, except when the first values were compared to the second (P greater than 0.05) and for CK-MB an overall significant differences were found at P less than 0.025 and P less than 0.001. On the other hand, quantification of ATP, CP and glycogen contents from simultaneous biopsies from the left and the right ventricular walls did not demonstrate significant differences between the two ventricles after the ischemic period.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantification of creatine phosphokinase and its isoenzyme MB, serum glutamic oxaloacetic transaminase and lactic dehydrogenase from different sources during aortic valve replacement procedure.

The diversity of conditions inducing an increase in CPK-MB, CPK, LDH and SGOT allows investigation of the quantitative evolution in cardiac patients during heart surgery. In nine patients submitted to valve replacement, three samples were taken respectively: one from the superior and the inferior caval veins and one another from the coronary sinus and immediately centrifuged. The sera were processed to quantitate the CPK, CPK-MB, LDH and SGOT through the three periods of observation. The three sites intended to explore the possible other sources of CPK-MB released at surgery: superior vena cava accounts for upper body regions, inferior vena cava for lower body regions and the coronary sinus for the heart itself. The three sites compared separately through the three periods did not show any significant differences. Only comparing the pre-CPK values to their homologous obtained during and after cardiopulmonary bypass, very evident differences could be registered (P less than 0,05 and less) for CPK, CPK-MB and LDH. While SGOT remained totally unchanged through the three periods. The evolutive CPK, CPK-MB and LDH increase accounted for high sensitivity of these enzymes to the variations of conditions during cardiac surgery. It is highly possible that other sources of CPK-MB could be dissiminated in the body and capable to produce valuable enzymatic amounts during and after cardiac surgery and that the heart is not exclusively alone in releasing this enzyme during cardiac ischemic arrest and in other circumstances. The real importance of CPK-MB principally and of CPK would be surestimated as conclusive parameters in diagnosis of myocardial damages during cardiac procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Review of respiratory infections in a developing country.

Two hundred and seventy-one patients were studied, who had been admitted to the University Hospital, Kinshasa between 1975 and May 1979 with pulmonary infections including pulmonary tuberculosis. Patients' ages ranged between 0-66 years (mean 12 years). Major incidence was between 0-5 years: 90 cases (33%) between 0-1 year and 86 cases (32%) between 1-5 years. Only 95 cases (35%) ranged from 5-66 years. Principal treatment was based on pleural drainage combined with medical treatment. In complicated cases, major thoracic surgery was performed. The mortality rate of 44 cases (16%) mainly very young children, demonstrates the severity of respiratory infections in childhood. It is concluded that many cases result from the poor general physical condition of most of these patients.

[Obstruction of the superior vena cava and right subclavian vein: a propos of 2 unusual cases]. / Obstruction de la veine cave supérieure et sous-clavière droite: a propos de deux cas peu communs.

Two uncommon cases of vein obstruction are presented. In the first case a syndrome of superior, caval vein obstruction was caused by idiopathic fibrous mediastinitis involving the vein wall, and creating a tumefaction in the lumen of the vein simulating the existence of a benign tumor (fibroma) of the wall. This tumefaction was removed by endvenectomy, and the venotomy was repaired by a pericardial patch. In the second case the obstruction of the right subclavian vein was caused by a stenosed valve without signs of inflammation nor consecutive thrombosis. Until the present day no other similar case of a stenosed valve in the right subclavian vein has been reported.