- A-Z Publications
- Cardiovascular Journal of Africa
- OA African Journal Archive
- Volume 8, Issue 5, 1997
Cardiovascular Journal of Africa - Volume 8, Issue 5, 1997
Volumes & issues
Volume 8, Issue 5, 1997
The metabolic syndrome and the effects of long-term low-dose diuretics in elderly white hypertensivesSource: Cardiovascular Journal of Africa 8, pp 257 –261 (1997)More Less
Objectives. To determine changes in the metabolic profile of elderly white patients with treated hypertension and the effect of withdrawal of prolonged thiazide therapy. Design. Fifty-eight patients (mean age 66.4 ï¿½ 1.4 years; 12 men, 46 women) treated with antihypertensive agents (including low-dose thiazides) underwent a standard 75 g oral glucose challenge with documentation of serial glucose, fasting insulin and lipid levels. In a subgroup (N = 14), low-dose thiazides were discontinued and the investigations were repeated 10 months later. Results. Twenty-four patients had normal glucose tolerance (NG) and 34 had abnormal glucose tolerance (AG). Of the latter, 9 had unsuspected diabetes mellitus. Total fasting cholesterol and triglyceride concentrations, diastolic blood pressure and recorded duration of hypertension were greater in AG than NG subjects. There was no evidence of more severe target organ damage (ECG or serum creatinine level) in AG than NG subjects. Following withdrawal of low-dose thiazides from a subgroup (N = 14) with AG, no change in glucose or insulin concentrations occurred: There was a statistically significant decrease in total cholesterol (P = 0.03), triglyceride (P = 0.0(1) and LDL cholesterol (P = 0.02) levels; the HDL cholesterol level increased (P = 0.003). Conclusion. Dyslipidaemia was closely related to the use of thiazides, albeit in a low dose, while the high incidence of abnormal glucose tolerance was related to factors other than thiazide use.
Author M.J. AntunesSource: Cardiovascular Journal of Africa 8, pp 265 –272 (1997)More Less
Mitral valvuloplasty has become a widely accepted and, in many instances, preferred option for the surgical treatment of mitral valve regurgitation. But the results are not as reproducible and predictable as those of valve replacement. Reoperation is more frequent than after valve replacement but is, for practical purposes, the only significant complication of the procedure. Several series have demonstrated the superiority of the long-term results of mitral valvuloplasty for most disease aetiologies. However, some doubts have been cast on the utilization of valvuloplasty in rheumatic mitral valve regurgitation. Nonetheless, my own experience in Johannesburg has demonstrated better global and event-free survival in patients who underwent valvuloplasty, even though these results in rheumatic patients are, in everybody's experience, inferior to those in cases of other types of pathology, especially in degenerative (myxomatous) disease. Of particular concern are cases of acute rheumatic carditis but, in my view, valvuloplasty may still be applied in selected cases. In the past decade several modifications of the technique initially developed by Carpentier in the 1970s have contributed to the improvement of the results. Among these are the utilisation of leaflet (partial) and chordal substitutes and new annuloplasty rings. However, the procedure remains dependent on a striking learning curve and, as a consequence, the results vary widely between different surgical teams. Nonetheless, it is fair to say that the improvements obtained thus far have . changed the indication to an earlier referral for surgery whenever the surgeon can safely predict reasonably good feasibility of the repair. In my experience, this is possible in the vast-majority (> 95%) of cases of myxomatous disease and in over 85% of cases of pure rheumatic regurgitation. Hence, it is increasingly important to maintain the. attitude that the needless excision of a mitral valve is a defeat to the surgeon.
Alpha-adrenergic receptor stimulation improves myocardial inotropy in the presence of chronic adrenergic antagonists and calcium channel blockers in the isolated rat heart after cardioplegic arrestSource: Cardiovascular Journal of Africa 8, pp 277 –284 (1997)More Less
This study was devised to evaluate the contribution of a-adrenergic stimulation to the inotropic response of the isolated rat heart subjected to a-adrenergic receptor antagonist (propranolol) and calcium channel blocker (nifedipine) before 45 minutes of normothermic cardioplegic arrest and during reperfusion. Rats were chronically treated with propranolol and nifedipine. They were then anaesthetised, and the hearts were isolated and retrogradely perfused. Thereafter function was quantified, and the' hearts subjected to 45 minutes of normothermic cardioplegic arrest followed by reperfusion. During reperfusion, dose-response curves were obtained for adrenaline, isoprenaline, phenylephrine and methoxamine. The a-adrenergic antagonist, prazosin, was also added in two series and the dose-response curves to adrenaline were repeated. The cardiac output was used as an indication of myocardial function. In the presence of propranolol and nifedipine, the dose-response curve for adrenaline was right-shifted. In the presence of prazosin, the inotropic dose-response curve also shifted to the right (compared with adrenaline only). Phenylephrine elicited a significant inotropic response, which was similar to that of adrenaline, while methoxamine was less effective. Results confirm that adrenaline stimulation results in .improved inotropy (and chronotropy) of the isolated rat hearts subjected to cardioplegia and reperfusion in the presence of propranolol and nifedipine. Data further suggest that some of the improved function is due to the adrenergic receptor stimulation associated with the adrenaline infusion.
Our experience with minimally invasive coronary artery bypass grafting and thoracoscopic internal mammary artery harvest with the Harmonic scalpelSource: Cardiovascular Journal of Africa 8, pp 285 –288 (1997)More Less
Background. Minimally invasive coronary artery bypass graft (MICABG) techniques are evolving. Thoracoscopic internal mammary artery (IMA) harvest is a demanding procedure. Our experiences with MICABG and a new IMA harvest technique (Wolf technique) are descriptionbed here. Materials and methods. Since October 1995, MICABG was applicable in 51 patients with a mean age of 70.2 ï¿½ 12.5 years, using 40 IMAs (29 left and 11 right), 7 gastroepiploic arteries, 4 saphenous vein grafts and 1 radial artery graft. Thirteen (25%) of the 51 patients were undergoing repeat surgery. A total of 27 IMAs (22 left and 5 right) were harvested with the Harmonic scalpel (Ethicon Endo-Surgery) using a thoracoscopic technique (Wolf technique). Results. MICABG was completed in 46 (90%) patients without cardiopulmonary bypass. Cardiopulmonary bypass was used in 5 patients (3 with small coronary arteries and 2 with intramyocardial arteries), in 3 of whom additional median sternotomies were made. One patient (2.0%), who suffered a pre-operative stroke, expired of stroke progression on the second postoperative day. Each of the IMA pedicles was completely dissected by means of the Wolf technique and 3-month postoperative Doppler studies were used to confirm patency. Conclusion. MICABG is a feasible and viable alternative surgical revascularisation procedure in selected patients with obstructive coronary disease. A new technique for thoracoscopic dissection of the IMA can facilitate the procedure.