Interpretation of LDH Values after Kidney Transplantation

Kidney transplantation is the gold-standard therapy for end-stage renal disease. However, in the early postoperative period following allograft kidney transplantation, insufficient graft function presents a diagnostic challenge to clinicians. Ischemic damage to the graft and/or an early autoimmune rejection may cause a decrease in function. Ischemic damage is a benign and transient condition, while acute immune rejection requires immediate therapy. A kidney graft ultrasound may produce a false negative result, and graft biopsy is invasive and slow to return results. Serum lactate dehydrogenase (LDH) is under examination as a possible tool for differential diagnosis between ischemic damage and immune rejection. Herein, we analyze the continuous lab results of four patients in the early post-transplantation period, showing patterns correlating with different clinical outcomes and prognoses. In our experience, a persistent elevated LDH accompanies ischemic damage. Immune rejection was, however, associated with a decrease in LDH. Hemodialysis was not a confounding factor, while packed red blood cell transfusion caused severe diagnostic problems.

Association of lactate dehydrogenase with mortality in incident hemodialysis patients

BACKGROUND

Lactate dehydrogenase (LDH) plays a role in the glucose metabolism of the human body. Higher LDH levels have been linked to mortality in various cancer types; however, the relationship between LDH and survival in incident hemodialysis (HD) patients has not yet been examined. We hypothesized that higher LDH level is associated with higher death risk in these patients.

METHODS

We examined the association of baseline and time-varying serum LDH with all-cause, cardiovascular and infection-related mortality among 109 632 adult incident HD patients receiving care from a large dialysis organization in the USA during January 2007 to December 2011. Baseline and time-varying survival models were adjusted for demographic variables and available clinical and laboratory surrogates of malnutrition-inflammation complex syndrome.

RESULTS

There was a linear association between baseline serum LDH levels and all-cause, cardiovascular and infection-related mortality in both baseline and time-varying models, except for time-varying infection-related mortality. Adjustment for markers of inflammation and malnutrition attenuated the association in all models. In fully adjusted models, baseline LDH levels ≥360 U/L were associated with the highest risk of all-cause mortality (hazard ratios = 1.19, 95% confidence interval 1.14-1.25). In time-varying models, LDH >280 U/L was associated with higher death risk in all three hierarchical models for all-cause and cardiovascular mortality.

CONCLUSIONS

Higher LDH level >280 U/L was incrementally associated with higher all-cause and cardiovascular mortality in incident dialysis patients, whereas LDH <240 U/L was associated with better survival. These findings suggest that the assessment of metabolic functions and monitoring for comorbidities may confer survival benefit to dialysis patients.

Lactate dehydrogenase isoenzymes in patients with acute exacerbation of chronic obstructive pulmonary disease: An exploratory cross-sectional study

We aimed to evaluate differences in serum lactate dehydrogenase (LDH) isoenzymes between patients hospitalized for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and other lower respiratory tract infections (LRTIs). Based on self-reported COPD diagnosis, 71 participants were divided into AECOPD (n = 38, 29 males, mean age 70.5 years) and LRTI (n = 33, 12 males, mean age 70.4 years) groups. Information on demographics, comorbidities, and COPD severity markers, as well as arterial blood gases and laboratory data were collected, while serum LDH electrophoresis was performed to examine the LDH isoenzymes. Adjusting for sex, age, comorbidities, degree of hypoxemia, inflammation markers, muscle and myocardial enzymes, and total serum LDH, the mean differences (95 % confidence intervals) in the ratios of serum LDH isoenzymes to total serum LDH between groups (LDHx_AECOPD - LDHx_LRTI) were statistically significant for LDH1 [4.9 (1.4 to 8.3)], LDH2 [3.0 (0.1 to 5.8)], LDH3 [-4.3 (-6.3 to -2.3)], and LDH4 [-3.2 (-4.9 to -1.5)]. A sum of LDH3 and LDH4 ratios below 29 % had the highest discriminative ability to classify a subject in the AECOPD group (AUC 0.841, sensitivity 76 %, specificity 87 %). Aerobic metabolic adaptive mechanisms in respiratory muscles during AECOPD could explain the above differences.

Volatile breath biomarkers for patient monitoring during haemodialysis

Patients with end-stage renal disease (ESRD) are at risk for a numerous complications. This study was intended to evaluate breath analysis for monitoring and therapy initiation under haemodialysis (HD). Exhaled alveolar air from 30 ESRD patients during 4 h thrice-weekly HD was analysed by means of HS-SPME-GC-MS. Venous blood samples were taken for determination of conventional serum parameters. Exhaled concentrations of isoprene (10-589 ppbV) were dropped at initiation of HD and increased at the end of HD. Isoprene concentration changes were similar to changes of serum LDH activities. Variation of exhaled acetone concentrations (59 to 8509 ppbV) was significantly lower in diabetic patients when compared to non-diabetics. Exhaled pentane (0.3 to 12 ppbV) increased at onset of HD and returned to baseline levels afterwards. Benzene concentrations showed typical washout characteristics. Ethanol and DMS concentrations remained constant during HD. Breath analysis can be used to recognize oxidative stress, metabolic conditions and haemolysis during HD. Hence, non-invasive breath testing could be used to monitor ESRD patients under HD and prevent them from being affected by well-known detrimental side effects of renal replacement therapy.

Iron status and cardiovascular risk factors in patients with haemodialysis versus patients with ischaemic heart disease

AIM

The study aimed to investigate whether imbalanced iron status in patients with haemodialysis coexisted with abnormal lipid profile, higher inflammatory status and altered growth hormone-insulin-like growth factor (GH-IGF)-I axis and to compare these biochemical markers with patients with ischaemic heart disease.

METHODS

Serum samples for biochemical and immunological analyses were collected from 74 normal subjects, 138 patients with ischaemic heart disease (IHD) and 115 patients on haemodialysis (HD).

RESULTS

Compared with normal subjects, lower serum iron, lower total iron-binding capacity (TIBC) and higher ferritin in HD patients coexisted with decreases in high-density lipoprotein cholesterol and total bilirubin as well as increases in lactate dehydrogenase (LDH), interleukin (IL)-6, C-reactive protein (CRP) and IL-10. Decreased IGF-I and increased GH were found in HD patients whereas unchanged GH-IGF axis were found in IHD patients. Compared with IHD, much higher ferritin, lower TIBC, lower bilirubin and higher LDH levels were found in HD patients.

CONCLUSION

Imbalanced iron status in patients on HD coexisted with abnormal lipid profiles, increased anaerobic activity and higher inflammatory status, which suggests that imbalanced iron status in HD patients may play a deleterious role in cardiovascular pathophysiology. Altered GH-IGF axis found in HD patients was more obvious than in IHD patients. This may imply that the GH-IGF axis system is modulated or adapted by HD.

Reviews: Altered Laboratory Findings Associated with End-Stage Renal Disease

Several laboratory parameters can be altered in advanced renal failure. Results may be difficult to interpret and may become misleading and unreliable in such a context. On the other hand, some of the alterations may reflect real abnormalities. Thus sufficient knowledge and careful judgment are required by the clinician. We reviewed different publications related to biochemical anomalies in renal failure and report some of the main findings. The sections are divided as follows: cardiovascular risk factors and markers, inflammation markers, pancreatic and liver function tests, hormones, bone turnover indices and parathyroid hormone assays, tumor markers, carbohydrate metabolism indicators, and others. The information provided should be useful to clinicians involved in the care of renal failure patients.

The influence of the haemodialysis procedure on platelets, coagulation and fibrinolysis

In end-stage renal disease, in particularly when treated with haemodialysis, the function of platelets, coagulation and fibrinolytic systems can be disturbed, thus contributing to either thrombotic or bleeding complications. It is important to know whether the currently used haemodialysis procedure itself (by biocompatible membranes and better anticoagulation with nandroparin) affects platelets, coagulation or fibrinolysis. In 15 patients who had been treated with chronic haemodialysis, we measured and compared platelet aggregation (induced by adenosine diphosphate, collagen and epinephrine), the markers of coagulation and fibrinolysis activation (thrombin-antithrombin complexes, thrombin fragments F1+2, D-dimer), and fibrinolytic parameters, i.e. fibrinogen, plasminogen, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 antigen and activity, before and immediately after the regular haemodialysis sessions. We did not find differences between pre- and post-haemodialysis platelet aggregation induced with all agents. Markers of coagulation and fibrinolysis activation remained unchanged during the process of haemodialysis. However, in post-haemodialysis samples, t-PA activity was significantly increased. Other fibrinolytic parameters remained unchanged. In conclusion, our results showed that the current technique of haemodialysis procedure does not affect platelet aggregation or activate coagulation, and therefore, does not contribute to a thrombotic tendency. However, it does directly affect fibrinolysis through activation of t-PA, which might be clinically relevant since this could increase the bleeding tendency in some haemodialysis patients.

Biocompatibility issues in hemodialysis

Hemodialysis, as a life-saving treatment modality for uremic patients, implies a repeated and compulsory contact of blood with foreign materials. As a consequence, biocompatibility problems are unavoidable. The same applies for the material used for the creation of vascular access, and for the alternative dialysis method, CAPD (continuous ambulatory peritoneal dialysis), although each system might cause its own and specific problems. Although in early dialysis the focus has been on maintenance of life and elimination of toxins, later on the important morbid implications of this lack of biocompatibility have been recognized. Eight major problems will be discussed, especially in the perspective of recent new findings in this field: (1) coagulation and clotting; (2) complement and leukocyte activation; (3) susceptibility to infection; (4) leaching or spallation; (5) surface alterations of solid materials; (6) allergic reactions; (7) shear; (8) transfer of compounds from contaminated dialysate. After description of the major biochemical and clinical implications of these problems, ways to prevent morbid events and future perspectives will be described.