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Clinical significance of serum magnesium levels in patients with heart failure with preserved ejection fraction.
Nishihara, T, Yamamoto, E, Sueta, D, Fujisue, K, Usuku, H, Oike, F, Takae, M, Arima, Y, Araki, S, Takashio, S, et al
Medicine. 2019;(38):e17069
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Abstract
Although serum magnesium (Mg) levels are closely associated with the prognosis of heart failure (HF) patients, the clinical significance of sMg levels on the cardiovascular outcomes of HF with preserved ejection fraction (HFpEF) patients is not fully understood. This study was a retrospective, single-center, observational study. We enrolled 452 consecutive HFpEF patients admitted to Kumamoto University Hospital. We defined lower sMg as <2.0 mg/dl (=0.8 mmol/L) based on recent clinical evidence and compared their clinical characteristics and prognosis. There were no significant differences between groups in the use of all medications (loop diuretics, mineralocorticoid receptor antagonists, renin-angiotensin-aldosterone system inhibitors, calcium channel blockers, beta blockers, statins, and Mg preparations). The lower sMg group showed a significantly higher prevalence of diabetes mellitus (DM), uric acid levels, and BNP levels compared with the higher sMg group. Kaplan-Meier curve revealed a significantly higher probability of HF-related events in the lower sMg group compared with the higher sMg group (log-rank test, P = .012). Multivariate Cox-proportional-hazard analysis revealed that the lower sMg group had significantly and independently higher probabilities of HF-related events compared with the higher sMg group (hazard ratio = 2.37, 95% confidence intervals = 1.27-4.41, P = .007). We reclassified the risk of HF-related events after adding the lower sMg to the other prognostic factors (age, previous hospitalization for HF, DM, Ln-BNP); the continuous net reclassification improvement was 29.0% (P = .041). sMg levels might provide important prognostic information in regard to HFpEF.
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"Initial, continuous and intermittent bolus" administration of minimally-diluted blood cardioplegia supplemented with potassium and magnesium for hypertrophied hearts.
Hayashi, Y, Ohtani, M, Hiraishi, T, Kobayashi, Y, Nakamura, T
Heart, lung & circulation. 2006;(5):325-31
Abstract
BACKGROUND Hypertrophied hearts are subject to the deleterious effects of intraoperative ischemia-reperfusion, and stable maintenance of myocardial cardioplegic arrest is essential. Continuous cardioplegia infusion appears an ideal modification to overcome this issue, except for a large amount of crystalloid solution infused into the myocardium. We previously introduced "initial, continuous and intermittent bolus" administration of minimally-diluted blood cardioplegia (mini-BCP) supplemented with potassium and magnesium, and this study was designed to elucidate its efficacy in patients with hypertrophied hearts. METHODS Thirty patients (M:F=17:13, 69.2+/-7.8 years) with left ventricular mass index greater than 150 g/m(2) who underwent aortic valve replacement between 1996 and 2002 were enrolled, and were allocated to one of the two groups. The same infusion protocol was used for both groups as follows: initial and intermittent (every 20 min) BCP was antegradely infused for 2 min at the rate of 200 mL/min, and continuous retrograde BCP flow rate was set at 60-100mL/min. Group C (n=15) received 4:1-diluted BCP modified with Buckberg solution, and Group M (n=15) were given mini-BCP supplemented with potassium (initial/others: 15.4/9.8 mEq/L) and magnesium (initial/others: 6.5/4.0 mEq/L). RESULTS Stable cardioplegic arrest was maintained in all study patients, and total amount of crystalloid solution as cardioplegia was lesser in Group M (79.4+/-27.5 mL) than in Group C (937.3+/-372. 1mL, p<0.01). Group M showed a higher incidence of spontaneous heartbeat recovery after aortic unclamping (13 versus 6, p<0.05) and a lower incidence of postoperative atrial fibrillation (0 versus 5, p<0.05). Postoperatively, maximum dopamine dose (3.35+/-2.27 microg/kg/min versus 5.49+/-2.30 microg/kg/min, p<0.05) and peak plasma creatine kinase-myocardial band (CK-MB) (21.7+/-7.2 IU/L versus 28.8+/-8.4 IU/L, p<0.05) were lower in Group M. Early postoperative echocardiography revealed a lower incidence of paradoxical ventricular septal motion (M versus C; 3 versus 10, p<0.05) and greater left ventricular ejection fraction (M versus C; 70.7+/-4.0% versus 67.0+/-5.3%, p<0.05) in Group M. CONCLUSIONS These results suggest that "initial, continuous and intermittent bolus" administration of mini-BCP, supplemented with potassium and magnesium, is a novel modification for patients with hypertrophied hearts in terms of simplifying the maintenance of cardioplegic arrest with beneficial myocardial protective effects.