High Left Ventricular Filling Pressure on Doppler Echocardiography Is Associated With Graft Failure and Overall Mortality Following Kidney Transplantation

Brain natriuretic peptide and N-terminal pro b-type natriuretic peptide in kidney transplantation: More than just cardiac markers

Although kidney transplantation (KT) is the best treatment option for most patients with end-stage kidney disease (ESKD) due to reduced mortality, morbidity and increased quality of life, long- term complications such as chronic kidney allograft dysfunction (CKAD) and increased cardiovascular disease burden are still major challenges. Thus, routine screening of KT recipients (KTRs) is very important to identify and quantify risks and guide preventative measures. However, no screening parameter has perfect sensitivity and specificity, and there is unmet need for new markers. In this review, we evaluate brain natriuretic peptide (BNP) and N-terminal pro b-type natriuretic peptide (NT-proBNP) as promising markers for risk stratification in the kidney transplant recipients (KTRs). The usefulness of these markers are already proven in heart failure, hypertension, coronary artery disease. In the context of KT, evidence is emerging. BNP and NT-proBNP has shown to be associated with kidney function, graft failure, echocardiographic parameters, major cardiovascular events and mortality but the underlying mechanisms are not known. Although BNP and NT-proBNP interact with immune system, renin angiotensin system and sympathetic system; it is not known whether these interactions are responsible for the clinical findings observed in KTRs. Future studies are needed whether these biomarkers show clinical efficacy, especially with regard to hard outcomes such as major adverse cardiovascular events and graft dysfunction and whether routine implementation of these markers are cost effective in KTRs.

Diastolic dysfunction for nephrologists: diagnosis at the point of care

Cardiovascular diseases are important causes of morbidity and mortality in the course of chronic kidney disease (CKD). Diastolic dysfunction (DD) may progress with the clinical manifestation of heart failure, known as heart failure with preserved ejection fraction, a condition that precedes systolic dysfunction. The early identification of DD by echocardiography at the point-of-care before the appearance of symptoms and signs of pulmonary congestion and the implementation of appropriate treatment can improve the prognosis of CKD. This review article briefly addresses DD in kidney disease and presents a practical approach to the echocardiographic diagnosis of DD at the point of care.

Systolic and diastolic dysfunction affects kidney outcomes in hospitalized patients

Backgrounds

Knowledge on cross-talk between the heart and kidney has been established by basic and clinical research. Nevertheless, the effects of systolic and diastolic heart dysfunctions on the development of acute kidney injury (AKI) and end-stage renal disease (ESRD) remain unresolved in hospitalized patients.

Methods

A total of 1327 hospitalized patients who had baseline transthoracic echocardiography performed were retrospectively analyzed. Patients were categorized by the quartiles of ejection fraction (EF) and the ratio of the early transmitral blood flow velocity to early diastolic velocity of the mitral annulus (E/e’). The odds ratios (ORs) for AKI and the hazard ratios (HRs) for ESRD were calculated after adjustment of multiple covariates.

Results

During hospital admission, AKI occurred in 210 (15.8%) patients. The lowest quartile of EF was associated with a risk of AKI (OR, 1.60 [1.07–2.41]) and the highest quartile of E/e’ was associated with a risk of AKI (OR, 1.90 [1.26–2.41]). When two echocardiographic parameters were combined, patients with a low EF (first to second quartiles) and high E/e’ (fourth quartile) showed the highest OR for AKI (OR, 2.27 [1.49–3.45]) compared with the counterpart patients. When the risk of ESRD was evaluated, E/e’, but not EF, was a significant parameter of high risk (fourth vs. first quartiles: HR, 4.13 [1.17–14.64]).

Conclusions

Baseline systolic and diastolic dysfunction is related to subsequent risks of AKI and ESRD in hospitalized patients. Monitoring of these parameters may be a useful strategy to predict the risk of these adverse events in the kidney.

Association Between Elevated Echocardiographic Index of Left Ventricular Filling Pressure and Acute Kidney Injury After Off-Pump Coronary Artery Surgery

BACKGROUND

The ratio of the early transmitral flow velocity to early diastolic velocity of the mitral annulus (E/e') is an echocardiographic index of mean left ventricular (LV) filling pressure. We investigated the association between the preoperative E/e' ratio and postoperative acute kidney injury (AKI) during off-pump coronary artery bypass surgery (OPCAB).Methods and Results:We reviewed 585 patients who underwent OPCAB and with preserved LV ejection fraction determined by preoperative echocardiography. AKI was determined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria. Multivariable logistic regression analysis was performed. E/e' was also analyzed as 3 categories (E/e' <8, 8≤E/e'≤15, and E/e' >15) and as a continuous variable. A propensity score analysis was used to match the patients with E/e' >15 and E/e' ≤15. A preoperative E/e' >15 was an independent predictor for AKI (odds ratio 3.01, 95% confidence interval 1.40-6.17). E/e' >15 was also an independent predictor for AKI when E/e' was analyzed with 3 categories or as a continuous variable. In the matched sample, the incidence of AKI and 1-year mortality was significantly higher in patients with E/e' >15.

CONCLUSIONS

Among patients undergoing OPCAB with preserved LV systolic function, a preoperative E/e' ratio >15 was an independent predictor of postoperative AKI. Measurement of the preoperative E/e' ratio may help to assess the risk of postoperative AKI.