Effects of a single, 24-hour, low-dose intravenous dobutamine infusion on left ventricular myocardial performance index in congestive heart failure: A prospective, nonrandomized study

AbstractBackground:Dobutamine, a predominantly beta-adrenergic sympathomimeticagent, is used for improving left ventricular (LV) systolic performance with different dosing regimens in patients with congestive heart failure (CHF). Myocardial performance index (MPI) is an indicator of LV global function that is correlated with LV end-diastolic pressure, and it is increased in CHF.Objective:The purpose of this study was to examine the effects of a single, 24-hour, low-dose, IV dobutamine infusion on LV systolic and diastolic function and on MPI in CHF as an indicator of LV global function, as well as the adverse effects (AEs) of the infusion.Methods:This prospective, nonrandomized study was conducted at theDepartment of Cardiology, Baskent University Hospital, Ankara, Turkey. Adult patients with LV ejection fraction (EF) <35%, sinus rhythm, and symptomatic CHF were treated using a standard protocol for at least 4 weeks. At the end of this period, patients with symptomatic CHF and EF <35% underwent echocardiography that included measuring isovolumic relaxation and contraction times (IRT and ICT, respectively) and LV ejection time (ET), and calculating LV MPI using the formula MPI = (IRT + ICT)/ET Dobutamine 2.5 μg/kg · min was then infused intravenously for 24 hours. Echocardiography was repeated 24 hours later and values were compared with preinfusion data. Patients were observed and monitored for CHF symptoms and AEs for 24 hours.Results:Forty-three patients were enrolled in the study, and 31 (22 men,9 women; mean [SD] age, 67.55 [11.78] years) continued after the 4-week standard-treatment period. Mean (SD) heart rate (74.93 [20.15] vs 80.23 [13.74] bpm, respectively), systolic blood pressure (129.00 [19.23] vs 126.67 [23.79] mm Hg), and diastolic blood pressure (75.80 [11.26] vs 74.96 [8.30] mm Hg) were statistically similar before and after the infusion. The mean (SD) end-diastolic volume was statistically similar to the preinfusion value (215.87 [76.74] vs 211.08 [65.51] mL); however, the mean (SD) end-systolic volume was significantly reduced (163.80 [63.86] vs 146.74 [53.12] mL; P = 0.01). Mean (SD) EF (25.33% [7.77%] vs 30.45% [7.63%]; P = 0.001) and stroke volume (SV) (54.92 [22.30] vs 63.59 [23.91] mL; P = 0.04) increased significantly. The mean (SD) early:late diastolic flow velocity (E/A ratio) (1.58 [1.36] vs 1.65 [1.27]), IRT (107.03 [35.37] vs 100.42 [34.32] ms), ICT (96.61 [34.27] vs 86.35 [44.80] ms), ET (240.65 [33.28] vs 243.48 [33.54] ms), and MPI (0.81% [0.28%] vs 0.78% [0.31%]) did not change significantly after dobutamine infusion. No AEs were observed.Conclusions:In this study of adult patients with symptomatic CHF, a single, 24-hour, low-dose, IV dobutamine infusion (2.5 μg/kg · min) was associated with decreased LV end-systolic volume and increased SV and EF However, LV diastolic function parameters, isovolumic time intervals, ET, and MPI were statistically similar to preinfusion values. The infusion was well tolerated

Serum cystatin C and neutrophil gelatinase-associated lipocalin in predicting the severity of coronary artery disease in diabetic patients

Objective: Cystatin C and neutrophil gelatinase-associated lipocalin (NGAL) are biomarkers of renal functions. We evaluated their roles in predicting the severity of coronary artery disease (CAD). Methods: Fifty-two consecutive type 2 diabetic patients (32 males, 65.7 +/- 8.6 years) who underwent coronary angiography (CAG) for stable CAD were included in this single-center, prospective, cross-sectional study. Patients with an estimated glomerular filtration rate <60mL/min/1.73m(2) and with a history of by-pass surgery and/or coronary stent implantation were excluded. The vessel score and Gensini score were calculated to assess the presence and severity of CAD. Mann-Whitney U test, Spearman test, and multiple linear regression analysis were used for the main statistical analyses. Results: Serum cystatin C levels were higher in patients with multivessel disease than in those with single vessel disease [1260 ng/mL (953-1640) vs. 977 ng/mL (599-1114), p=0.017]. According to the median Gensini score, the higher score group also had higher cystatin C levels than the lower score group [1114 ng/mL (948-1567) vs. 929 ng/mL (569-1156), p=0.009]. However, serum NGAL levels were similar between these subgroups. There was a positive correlation between cystatin C and Gensini score (r=0.334, p=0.016). Multiple linear regression analysis revealed serum cystatin C as an independent predictor of the Gensini score (beta=0.360, t=2.311, p=0.026). These results may aid in defining cystatin C as a surrogate marker of the extent of CAD in further clinical trials. Conclusion: Serum Cystatin C, but not NGAL levels, could predict the severity of CAD in diabetic patients

Could plasma asymmetric dimethylarginine level be a novel predictor beyond the classic predictors of stent restenosis?

Objective: The aim of this study was to investigate the factors associated with coronary stent restenosis and if there is an association between plasma asymmetric dimethylarginine (ADMA) levels and stent restenosis. Methods: Ninety-one patients, who had a history of coronary bare metal stent implantation due to any cause in the last one year period, were admitted to this observational cross-sectional study. Coronary angiography was performed to all patients and quantitative angiography was used to determine the presence of stent restenosis. Laboratory parameters and angiographic features that contribute to stent restenosis were evaluated. Plasma ADMA levels were measured by using high performance liquid chromatography. Logistic regression analysis was used to determine the independent factors of stent restenosis. Results: Angiographic restenosis was found in 35 patients (38.5%). Stent diameter (p=0.038) and left ventricular ejection fraction (p=0.023) were lower and stent implantation history due to acute coronary syndrome (p=0.029), plasma ADMA level (5.0 +/- 1.8x10(-4) mmol/L vs. 3.9 +/- 1.0x10(-4) mmol/L, p=0.001), C-reactive protein concentration (p=0.016), white blood cell count (p=0.044) and stent length (p=0.005) were higher in patients with restenosis. Plasma ADMA level (beta=0.536; OR: 1.710; CI: 1.022-2.861; p=0.041), C-reactive protein concentration (beta=0.062; OR: 1.064; CI: 1.003-1.129; p=0.041), stent diameter (beta=-3.047; OR: 0.048; CI: 0.007-0.313; p=0.002) and length (beta=0.165; OR: 1.179; CI: 1.036-1.343; p=0.013) were found to be the independent predictors of stent restenosis in logistic regression analysis. Conclusion: We conclude that plasma ADMA levels may be used as a novel marker for stent restenosis beyond the classic stent restenosis markers