Platelet Counts, Acute Kidney Injury, and Mortality after Coronary Artery Bypass Grafting Surgery.

BACKGROUND: Cardiac surgery requiring cardiopulmonary bypass is associated with platelet activation. Because platelets are increasingly recognized as important effectors of ischemia and end-organ inflammatory injury, the authors explored whether postoperative nadir platelet counts are associated with acute kidney injury (AKI) and mortality after coronary artery bypass grafting (CABG) surgery. METHODS: The authors evaluated 4,217 adult patients who underwent CABG surgery. Postoperative nadir platelet counts were defined as the lowest in-hospital values and were used as a continuous predictor of postoperative AKI and mortality. Nadir values in the lowest 10th percentile were also used as a categorical predictor. Multivariable logistic regression and Cox proportional hazard models examined the association between postoperative platelet counts, postoperative AKI, and mortality. RESULTS: The median postoperative nadir platelet count was 121 × 10/l. The incidence of postoperative AKI was 54%, including 9.5% (215 patients) and 3.4% (76 patients) who experienced stages II and III AKI, respectively. For every 30 × 10/l decrease in platelet counts, the risk for postoperative AKI increased by 14% (adjusted odds ratio, 1.14; 95% CI, 1.09 to 1.20; P < 0.0001). Patients with platelet counts in the lowest 10th percentile were three times more likely to progress to a higher severity of postoperative AKI (adjusted proportional odds ratio, 3.04; 95% CI, 2.26 to 4.07; P < 0.0001) and had associated increased risk for mortality immediately after surgery (adjusted hazard ratio, 5.46; 95% CI, 3.79 to 7.89; P < 0.0001). CONCLUSION: The authors found a significant association between postoperative nadir platelet counts and AKI and short-term mortality after CABG surgery.

Calibrated integrated backscatter and myocardial fibrosis in patients undergoing cardiac surgery.

Objective - The reported association between calibrated integrated backscatter (cIB) and myocardial fibrosis is based on study of patients with dilated or hypertrophic cardiomyopathy and extensive (mean 15–34%) fibrosis. Its association with lesser degrees of fibrosis is unknown. We examined the relationship between cIB and myocardial fibrosis in patients with coronary artery disease.

Methods - Myocardial histology was examined in left ventricular epicardial biopsies from 40 patients (29 men and 11 women) undergoing coronary artery bypass graft surgery, who had preoperative echocardiography with cIB measurement.

Results - Total fibrosis (picrosirius red staining) varied from 0.7% to 4%, and in contrast to previous reports, cIB showed weak inverse associations with total fibrosis (r=−0.32, p=0.047) and interstitial fibrosis (r=−0.34, p=0.03). However, cIB was not significantly associated with other histological parameters, including immunostaining for collagens I and III, the advanced glycation end product (AGE) Nε-(carboxymethyl)lysine (CML) and the receptor for AGEs (RAGE). When biomarkers were examined, cIB was weakly associated with log plasma levels of amino-terminal pro-B-type natriuretic peptide (r=0.34, p=0.03), creatinine (r=0.33, p=0.04) and glomerular filtration rate (r=−0.33, p=0.04), and was more strongly associated with log plasma levels of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) (r=0.44, p=0.01) and soluble RAGE (r=0.53, p=0.002).

Conclusions - Higher cIB was not a marker of increased myocardial fibrosis in patients with coronary artery disease, but was associated with higher plasma levels of sVEGFR-1 and soluble RAGE. The role of cIB as a non-invasive index of fibrosis in clinical studies of patients without extensive fibrosis is, therefore, questionable.

Optimization of bypass graft using FSI numerical method

It is well documented in literature that the coronary artery bypass graft is normally fail after a short period of time, due to the development of plaque known as intimal hyperplasia within the graft. Various in vivo and in vitro studies have linked the development of intimal hyperplasia to the abnormal hemodynamics and compliance mismatch. Therefore, it is essential to fully understand the relationship between the hemodynamics inside the coronary artery bypass and its mechanical and geometrical characteristics under the correct physiological conditions. In this work, hemodynamic of the bypass graft is studied numerically. The effect of the host and graft diameters ratio, the angle of anastomosis and the graft configuration on the local flow patterns and the distribution of wall shear stress are examined. The pulsatile waveforms boundary conditions are adopted from in vivo measurement data to study the hemodynamics of composite grafts namely Consequence and Y grafting in terms temporal and spatial distributions of the blood flows. Moreover, various non-Newtonian and Newtonian models of blood have been carried out to examine the numerical simulation of blood flow in stenosis artery. The results are presented and discussed for various operating conditions.

Analysis of renal function after on and off pump coronary artery bypass grafting

Cardiopulmonary bypass (CPB) is often associated with renal dysfunction, as measured by plasma creatinine levels and hemodialysis rates. Aim. To compare creatinine clearance (CrCl), estimated with the Cockroft and Gault formula, between patients undergoing off-pump coronary artery bypass grafting (OPCAB) versus on-pump CABG (on-CAB). Material and methods. Between April 2008 and April 2009, 119 patients underwent coronary bypass graft surgery. Fifty-eight (58) of these patients underwent OPCAB while 61 had on-CAB. Creatinine clearance, plasma creatinine levels, and clinical outcome were compared between the groups. A creatinine clearance value of 50 mL/minute was accepted as the lowest limit of normal renal function. Results. There were two hospital deaths caused by sepses after pulmonary infection. Creatinine clearance (Preoperative OPCAB 73,64±33,72 x on-CAB 75,70±34,30mL/min; discharge OPCAB 75,73±35,07 x on-CAB 79,07±34,71 mL/ min; p=0,609), and creatinine levels (Preoperative OPCAB 1,04±0,38 x on-CAB 1,13±0,53 mg/dL; discharge OPCAB 1,12±0,79 x on-CAB 1,04±0,29mg/dL; p=0,407) did not show statistically inter-group differences. Conclusion. Deterioration in renal function is associated with higher rates of postoperative complications. No significant difference in CrCl could be demonstrated between the groups.

Levothyroxine Absorption in Morbidly Obese Patients Before and After Roux-En-Y Gastric Bypass (RYGB) Surgery

Roux-en-Y gastric bypass (RYGB) modifies the anatomical structure of the upper intestine tract, reduces gastric acid secretion, and may impair LT4 absorption. The aim of this study was to evaluate the LT4 absorption in morbidly obese patients before and after RYGB. Thirty morbidly obese patients were divided in two groups: The NS group included 15 patients before RYGB surgery (BMI = 43.1 +/- 4 kg/m(2)), and the S group included 15 patients after surgery (BMI = 37.3 +/- 4 kg/m(2)). Two baseline samples were collected, and 600 mu g of oral LT4 tablets were administered. Blood samples were collected at 30, 60, 120, 180, 240, 300, and 1440 min. Serum-free T4 (FT4), total T4 (TT4), and TSH were measured at each time point. The increase in TT4, FT4, and TSH (Delta TT4, Delta FT4, and Delta TSH) was calculated, subtracting from the baseline mean value. The pharmacokinetics parameters regarding LT4 absorption, maximum Delta TT4, and area under the curve(AUC) of both Delta TT4 and Delta FT4 were significantly higher in the S group compared with the NS group (p < 0.05). It was observed, however, that there was a significant delay in the absorption of LT4 in the S group. Basal serum TSH and leptin levels were higher in the NS group (p = 0.016 and 0.026, respectively), whereas basal serum TT4, FT4, Delta TSH, and the AUC of Delta TSH were similar between groups. In this study, we have demonstrated that Roux-en-Y bypass surgery does not diminish LT4 absorption. A small but significant delayed absorption of LT4, however, was observed in patients after surgery.

Cost-Effectiveness Analysis for Surgical, Angioplasty, or Medical Therapeutics for Coronary Artery Disease 5-Year Follow-Up of Medicine, Angioplasty, or Surgery Study (MASS) II Trial

Background-The Second Medicine, Angioplasty, or Surgery Study (MASS II) included patients with multivessel coronary artery disease and normal systolic ventricular function. Patients underwent coronary artery bypass graft surgery (CABG, n = 203), percutaneous coronary intervention (PCI, n = 205), or medical treatment alone (MT, n = 203). This investigation compares the economic outcome at 5-year follow-up of the 3 therapeutic strategies. Methods and Results-We analyzed cumulative costs during a 5-year follow-up period. To analyze the cost-effectiveness, adjustment was made on the cumulative costs for average event-free time and angina-free proportion. Respectively, for event-free survival and event plus angina-free survival, MT presented 3.79 quality-adjusted life-years and 2.07 quality-adjusted life-years; PCI presented 3.59 and 2.77 quality-adjusted life-years; and CABG demonstrated 4.4 and 2.81 quality-adjusted life-years. The event-free costs were $9071.00 for MT; $19 967.00 for PCI; and $18 263.00 for CABG. The paired comparison of the event-free costs showed that there was a significant difference favoring MT versus PCI (P<0.01) and versus CABG (P<0.01) and CABG versus PCI (P<0.01). The event-free plus angina-free costs were $16 553.00, $25 831.00, and $24 614.00, respectively. The paired comparison of the event-free plus angina-free costs showed that there was a significant difference favoring MT versus PCI (P=0.04), and versus CABG (P<0.001); there was no difference between CABG and PCI (P>0.05). Conclusions-In the long-term economic analysis, for the prevention of a composite primary end point, MT was more cost effective than CABG, and CABG was more cost-effective than PCI.