Intramyocardial hemorrhage and microvascular obstruction after primary percutaneous coronary intervention

Reperfusion may cause intramyocardial hemorrhage (IMH) by extravasation of erythrocytes through severely damaged endothelial walls. The purpose of the study was to evaluate the clinical significance of IMH in relation to infarct size, microvascular obstruction (MVO) and function in patients after primary percutaneous intervention. Forty-five patients underwent cardiovascular MR imaging (CMR) 1 week and 4 months after primary stenting for a first acute myocardial infarction. T2-weighted spin-echo imaging (T2W) was used to assess infarct related edema and IMH, and delayed enhancement (DE) was used to assess infarct size and MVO. Cine CMR was used to assess left ventricular volumes and function at baseline and at 4 months follow-up. In 22 (49%) patients, IMH was detected as areas of attenuated signal in the core of the high signal intensity region on T2W images. Patients with IMH had larger infarcts, higher left ventricular volumes and lower ejection fraction. Contrast-to-noise ratio (CNR) between hyperintense periphery and the hypo-intense core of the T2W ischemic area correlated to peak CKMB, total infarct size and MVO size. Using univariable analysis, CNR predicted ejection fraction at baseline (β = −0.62, P = 0.003) and follow-up (β = −0.84, P < 0.001). However, after multivariable analysis, baseline ejection fraction and presence of MVO were the only parameters that predicted functional changes at follow-up. IMH was found in the majority of patients with MVO after reperfused myocardial infarction. It was closely related to markers of infarct size, MVO and function, but did not have prognostic significance beyond MVO.     

Preoperative feeding preserves heart function and decreases oxidative injury in rats

OBJECTIVE: The nutritional status of a patient has been implicated as an important factor in the development of postoperative complications. Fasting before an operation may have detrimental effects on the metabolic state. We hypothesized that there was a positive correlation between preoperative nutritional status and postoperative organ function. METHODS: Preoperative feeding was compared with fasting with respect to effects on organ function and biochemical parameters in an animal model of extensive large abdominal surgery. Male Wistar rats were fed ad libitum or fasted for 16 h, after which the arteria mesenterica superior was clamped for 60 min followed by 180 min of reperfusion. RESULTS: After the ischemic period, heart function was significantly better in animals that were fed ad libitum than in fasted animals. Moreover, after intestinal ischemia and reperfusion, fed rats showed significantly higher levels of intestinal adenosine triphosphate and a significantly higher malondialdehyde concentration in the intestine and lung than did fasted rats. The ratio of adenosine triphosphate to adenosine diphosphate in the liver, an indicator of energy status, in fed rats was similar to that in a sham group, whereas fasted animals showed a significantly lower value. CONCLUSIONS: Preoperative nutrition in contrast to fasting may attenuate ischemia/reperfusion-induced injury and preserve organ function in the rat.     

Use of a mixture of medium-chain triglycerides and longchain triglycerides versus long-chain triglycerides in critically ill surgical patients: a randomized prospective double-blind study

Twenty critically-ill surgical patients who needed total parenteral nutrition were randomly enrolled in a double-blind study comparing two intravenous fat emulsions: one containing a mixture of 50% medium-chain triglycerides and 50% long-chain triglycerides and another containing 100% longchain triglycerides. The purpose of this study was to investigate metabolic and biochemical differences between both emulsions with special reference to liver enzymes. After a baseline period of 24 h with only glucose and NaCl infusion, the lipid emulsion was added continuously during 24 h over 5 days. The parenteral nutrition was administered in mixture bags containing amino-acids, glucose and lipids together. Two-thirds of the non-protein calories were administered as glucose 40% and one third as either long-chain triglycerides or a mixture of medium-chain triglycerides and long-chain triglycerides. The total amount of non-protein calories received was the measured energy expenditure during the baseline period plus 10% and was fixed during the study. Plasma substrate concentrations, energy expenditure, and nitrogen balance were determined and arterial blood samples were taken. No toxic effects or complications attributable to one of the two emulsions were observed. There was no significant difference in energy expenditure, nitrogen balance, liver function tests, carnitine, transferrin, pre-albumin, albumin, cholesterol, triglycerides and free fatty acids. The only parameter that showed a different pattern of reaction between the two emulsions was serum bilirubin concentration. In this study no evidence of any advantageous effect of a mixture of medium-chain triglycerides and long-chain triglycerides was seen.     

Right atrial and ventricular strain detects subclinical changes in right ventricular function in precapillary pulmonary hypertension

The International Journal of Cardiovascular Imaging - Right ventricular (RV) ejection fraction (EF) by cardiac magnetic resonance (CMR) correlates to outcome in precapillary pulmonary hypertension...     

The asymmetrical dimethylarginine (ADMA)-multiple organ failure hypothesis

Development of multiple organ failure is the most complex problem in critically ill patients, and is associated with a high mortality. Asymmetrical dimethylarginine (ADMA) is an endogenously produced inhibitor of nitric oxide synthase, of which the clinical importance is currently being revealed. In Nijveldt et al. (The liver is an important organ in the metabolism of asymmetrical dimethylargenine (ADMA) Clin Nutr 2003; 22: 17-22) we showed that plasma ADMA concentration is elevated in critically ill patients and significantly related to hepatic function. Moreover, plasma ADMA concentration emerged as a strong and independent risk factor for ICU mortality in these patients. Here, we hypothesize that accumulation of ADMA is a causative factor in the development of multiple organ failure by interfering with important physiological functions of nitric oxide production.     

Modulation of asymmetric dimethylarginine in critically ill patients receiving intensive insulin treatment: a possible explanation of reduced morbidity and mortality?

OBJECTIVE: Asymmetric dimethylarginine, which inhibits production of nitric oxide, has been shown to be a strong and independent predictor of mortality in critically ill patients with clinical evidence of organ dysfunction. Interestingly, intensive insulin therapy in critically ill patients improved morbidity and mortality, but the exact mechanisms by which these beneficial effects are brought about remain unknown. Therefore, we aimed to investigate whether modulation of asymmetric dimethylarginine concentrations by intensive insulin therapy is involved in these effects. DESIGN: A prospective, randomized, controlled trial. SETTING: A 56-bed predominantly surgical intensive care unit in a tertiary teaching hospital. PATIENTS: From a study of 1,548 critically ill patients who were randomized to receive either conventional or intensive insulin therapy, we included 79 patients who were admitted to the intensive care unit after complicated pulmonary and esophageal surgery and required prolonged (>/=7 days) intensive care. INTERVENTIONS: Determination of asymmetric dimethylarginine concentrations. MEASUREMENTS AND MAIN RESULTS: Asymmetric dimethylarginine concentrations were determined with high-performance liquid chromatography on the day of admission, on day 2, on day 7, and on the last day at the intensive care unit. Although the asymmetric dimethylarginine levels did not change between day 0 and day 2 in patients receiving intensive insulin treatment, there was a significant increase during this period in the conventionally treated patients (p = .043). Interestingly, the mean daily insulin dose was inversely associated with the asymmetric dimethylarginine concentration on the last day (r = -.23, p = .042), and the asymmetric dimethylarginine concentration on the last day at the intensive care unit was significantly lower in the intensive insulin treatment group (p = .048). Furthermore, asymmetric dimethylarginine was positively associated with duration of intensive care unit stay, duration of ventilatory support, duration of inotropic and vasopressor treatment, number of red cell transfusions, duration of antibiotic treatment, presence of critical illness polyneuropathy, mean Acute Physiology and Chronic Health Evaluation II score, and cumulative Therapeutic Intervention Scoring System-28 score. In addition, asymmetric dimethylarginine levels in patients who died were significantly higher compared with survivors, and changes in the course of asymmetric dimethylarginine plasma concentrations were predictive for adverse intensive care unit outcome. CONCLUSIONS: Modulation of asymmetric dimethylarginine concentration by insulin at least partly explains the beneficial effects found in critically ill patients receiving intensive insulin therapy.     

Semi-quantitative assessment of right ventricular function in comparison to a 3D volumetric approach: A cardiovascular magnetic resonance study

Right ventricular (RV) volume measurements with cardiovascular magnetic resonance (CMR) is considered the gold standard, but acquisition and analysis remain time-consuming. The aim of our study was therefore to investigate the accuracy and performance of a semi-quantitative assessment of RV function in CMR, compared to the standard quantitative approach. Seventy-five subjects with pulmonary hypertension (15), anterior myocardial infarction (15), inferior myocardial infarction (15), Brugada syndrome (15) and normal subjects (15) underwent cine CMR. RV end-systolic and end-diastolic volumes were determined to calculate RV ejection fraction (EF). Four-chamber cine images were used to measure tricuspid annular plane systolic excursion (TAPSE). RV fractional shortening (RVFS) was calculated by dividing TAPSE by the RV end-diastolic length. RV EF correlated significantly with TAPSE (r = 0.62, p < 0.01) and RVFS (r = 0.67, p < 0.01). Sensitivity to predict RV dysfunction was comparable between TAPSE and RVFS, with higher specificity for RVFS, but comparable areas under the ROC curve. Intra- and inter-observer variability of RV EF was better than TAPSE (3%/4% versus 7%/15%, respectively). For routine screening in clinical practice, TAPSE and RVFS seem reliable and easy methods to identify patients with RV dysfunction. The 3D volumetric approach is preferred to assess RV function for research purposes or to evaluate treatment response.