ABSTRACT
BACKGROUND: The therapeutic role of L-carnitine (LC) on the anemia of chronic hemodialized patients is still controversial. In order to clarify the long-term effects of LC administration on renal anemia, an open, observational 12-month study was performed. METHODS: Twenty stable outpatients undergoing hemodialysis were administered LC 900 mg p.o. daily for 12 months. The recombinant human erythropoietin (rHuEPO) dose was adjusted monthly when necessary to maintain the target hemoglobin (Hb) levels. RESULTS: The free LC level increased, while the acyl/free LC ratio decreased significantly 3 months after administration and was then maintained until the end of the study. There was no difference in Hb levels and the erythropoietin resistance index (ERI) during the study period. However, it was observed that ERI decreased significantly in 7 out of 18 patients (responders) 5 months after LC administration and was maintained thereafter (almost 40% reduction of the rHuEPO dose). The acyl/free carnitine ratio at baseline was the most contributing factor distinguishing responders from nonresponders. CONCLUSION: Although the beneficial effect of LC supplementation on renal anemia was not observed in all patients, at least 40% of the patients (responders) showed a significant improvement in ERI after long-term LC administration.
ABSTRACT
BACKGROUND: It is well known that the physical activity in chronic hemodialysis patients decreases compared to that in normal subjects. In order to investigate the effects of L-carnitine on physical capacity and lipid metabolism, a cardiopulmonary exercise test using a bicycle ergometer was performed before and after 3 months of oral L-carnitine supplementation under double-blind conditions. METHODS AND RESULTS: A total of 20 stable outpatients undergoing hemodialysis treatment were randomly divided into 2 groups: controls receiving placebo and patients receiving 900 mg L-carnitine p.o. daily. The levels of free and acyl carnitine increased significantly from 22.9 ± 7.3 to 149.9 ± 51.8 µmol/l and from 16.0 ± 2.8 to 100.3 ± 50.2 µmol/l, respectively, in the L-carnitine group; however, there was no significant change in other plasma lipid profiles. The exercise time was decreased and the heart rate at the anaerobic threshold was increased in the control group 3 months after the study period, but there were no such changes observed in the L-carnitine group. The minute ventilation/CO2 output slope increased significantly from 38.9 ± 7.8 to 43.8 ± 11.8 in the L-carnitine group. It has been speculated that a shift in the energy source occurs from carbohydrate to lipid, in terms of an increase of oxygen demand. CONCLUSION: L-Carnitine supplementation might have some beneficial effects on the physical capacity of chronic hemodialysis patients due to the improvement of the lipid metabolism in the muscle.
ABSTRACT
BACKGROUND: Persistent hypotension with dynamic midventricular obstruction (MVO) in patients with transient left ventricular (LV) apical ballooning (Tako-tsubo cardiomyopathy) is an important complication that needs to be treated. PURPOSE: The objective of this study is to determine the effects of intravenous propranolol challenge on MVO in transient LV apical ballooning. SUBJECTS AND METHODS: Thirty-four patients (12 males, 22 females, mean age 64 +/- 17 years, age range 22-84 years) with LV apical ballooning were enrolled. The hemodynamic and echocardiographic effects of propranolol (0.05 mg/kg, maximum 4 mg) were analyzed in 13 patients. RESULTS: (1) Midventricular obstruction was present in 8 (24%) of 34 patients, and the pressure gradient (PG) ranged from 28 to 140 mm Hg. (2) Patients with MVO had similar demographic and clinical characteristics (symptoms, peak creatine kinase, plasma catecholamine levels) as those without MVO; however, in patients with MVO, abnormal Q waves on electrocardiogram and hypotension were more prevalent. (3) In the MVO group, intravenous propranolol changed the PG from 90 +/- 42 to 22 +/- 9 mm Hg, the systolic blood pressure (SBP) from 85 +/- 11 to 116 +/- 20 mm Hg, and the LV ejection fraction (LVEF) from 30% +/- 7% to 43% +/- 4%. (4) In all subjects, the changes in the PG after propranolol injection had a significant linear correlation with the SBP and LVEF changes: deltaSBP = 4.738 + 0.315 x deltaPG (r = 0.689 (P < .001) and deltaLVEF = 2.973 + 0.1321 x deltaPG (r = 0.715, P < .001). CONCLUSION: Intravenous propranolol is useful for treating dynamic MVO in patients with transient LV apical ballooning.
