Thiamine as an outcome predictor in postoperative CABG patients

Introduction

Coronary artery bypass graft surgery (CABG) is one of the most performed cardiovascular procedures worldwide. Despite good outcomes, CABG induces systemic inflammation, increases oxidative stress and increases catabolism. As thiamine act as a cofactor in glucose metabolism and glutathione synthesis, its deficiency could have a high prevalence in critically ill patients.

Purpose

To assess the association between plasma thiamine concentrations and clinical outcomes and 30-day mortality in patients undergoing non-emergency CABG.

Methods

Prospective and observational study that included consecutive patients older than 18 years undergoing CABG that assigned the consent form. Plasma thiamine concentrations were determined before and 24 hours after the procedure by the high-performance liquid chromatography method. The clinical outcomes evaluated were perioperative acute myocardial infarction, heart failure, cardiogenic shock, arrhythmias, stroke and acute kidney injury. Mortality was evaluated on the 30th day after CABG.

Results

The study included 131 patients submitted to CABG. The mean age was 61±9.1 years, 73.3% were men, and the mean EuroScore II value was 1.78±1.3%. Before CABG, plasmatic thiamine concentration was 33±15ng/ml, and 15% of the patients had thiamine deficiency. After CABG, plasmatic thiamine concentration was 20±8ng/ml. All patients diminished plasmatic thiamine concentration after CABG. Mortality was 16% and 24% of patients presented acute kidney injury. Combined outcomes, which included the presence of acute myocardial infarction, heart failure, cardiogenic shock, arrhythmias, stroke, acute kidney injury or death, was present in 52% of the patients. Percentage of thiamine variation between before and after CABG was not associated with mortality (34±14 vs 41±10%; p=0.063); however, it was associated with acute kidney injury (40±14 vs 34±13%; p=0.027) and combined outcomes (37±13 vs 33±14%; p=0.035).

Conclusion

Percentage of thiamine variation from before to after CABG was associated with acute kidney injury and combined outcomes in these patients.

Funding Acknowledgement

Type of funding sources: None.

Current perspectives on defining and mitigating frailty in relation to critical illness

Up to half of ICU survivors, many of whom were premorbidly well, will have residual functional and/or cognitive impairment and be vulnerable to future health problems. Frailty describes vulnerability to poor resolution of homeostasis after a stressor event but it is not clear whether the vulnerability seen after ICU correlates with clinical measures of frailty. In clinical practice, the scales most commonly used in critically ill patients are based on the assessment of severity and survival. Identification and monitoring of frailty in the ICU may be an alternative or complimentary approach, particularly if it helps explain vulnerability during the recovery and rehabilitation period. The purpose of this review is to discuss the use of tools to assess frailty status in the critically ill, and consider their importance in clinical practice. Amongst these, we consider biomarkers with potential to identify patients at greater or lesser risk of developing post-ICU vulnerability.

Effects of early aldosterone antagonism on cardiac remodeling in rats with aortic stenosis-induced pressure overload

Aldosterone plays a pivotal role in the pathophysiology of systolic heart failure. However, whether early aldosterone antagonism improves cardiac remodeling during persistent pressure overload is unsettled. We evaluated the effects of aldosterone antagonist spironolactone on cardiac remodeling in rats with ascending aortic stenosis (AS).

METHODS

Three days after inducing AS, weaning rats were randomized to receive spironolactone (AS-SPR, 20mg/kg/day) or no drug (AS) for 18weeks, and compared with sham-operated rats. Myocardial function was studied in isolated left ventricular (LV) papillary muscles.

STATISTICAL ANALYSES

ANOVA or Kruskal-Wallis tests.

RESULTS

Echocardiogram showed that LV diastolic (Sham 8.73±0.57; AS 8.30±1.10; AS-SPR 9.19±1.15mm) and systolic (Sham 4.57±0.67; AS 3.61±1.49; AS-SPR 4.62±1.48mm) diameters, left atrial diameter (Sham 5.80±0.44; AS 7.15±1.22; AS-SPR 8.02±1.17mm), and LV mass were higher in AS-SPR than AS. Posterior wall shortening velocity (Sham 38.5±3.8; AS 35.6±5.6; AS-SPR 31.1±3.8mm/s) was lower in AS-SPR than Sham and AS; E/A ratio was higher in AS-SPR than Sham. Developed tension was lower in AS and AS-SPR than Sham. Time to peak tension was higher in AS-SPR than Sham and AS after post-rest contraction. Right ventricle weight was higher in AS-SPR than AS, suggesting more severe heart failure in AS-SPR than AS. Interstitial collagen fractional area and myocardial hydroxyproline concentration were higher in AS than Sham. Metalloproteinase-2 and -9 activity, evaluated by zymography, did not differ between groups.

CONCLUSION

Early spironolactone administration causes further hypertrophy in cardiac chambers, and left ventricular dilation and dysfunction in rats with AS-induced chronic pressure overload.