Martin Bernardi

Acute Kidney Injury and Outcome After Heart Transplantation: Large Differences in Performance of Scoring Systems.

Background Kidney function is an important aspect for patient outcome after heart transplantation (HTX). Acute kidney injury (AKI) is defined by changes in serum creatinine (SCr) and diuresis with risk/injury/failure/loss/end stage (RIFLE), acute kidney injury network (AKIN), or kidney disease: improving global outcomes (KDIGO) scores. Methods We investigated the effect of perioperative AKI on 1-year mortality after HTX over a period of 10 years at a single-center university hospital. Multivariable Cox proportional-hazards regression analyzed the association between 1-year mortality and potential risk factors. Receiver operating curves for 1-year mortality were calculated to determine sensitivity and specificity of scores. Results Sixty of 346 patients (17%) died within the first year. Acute kidney injury was a predictor of mortality only in the high-risk AKI groups of all scores: Hazard ratios (95% confidence interval) for RIFLE F: 7.164 (3.307-15.523); KDIGO/AKIN stage 3: 3.492 (2.006-6.081). Within each score, we identified patient groups, which had no elevated risk for an adverse outcome despite their allocation to the milder forms of AKI. In multivariable regression analysis, primary graft dysfunction was the predominant perioperative risk factor for 1-year mortality. Conclusions In contrast to other patient cohorts, mild forms of perioperative AKI are of subordinate influence on patient outcome in HTX.

Impact of preoperative serum creatinine on short- and long-term mortality after cardiac surgery: a cohort study

BACKGROUND Preoperative renal insufficiency is an important predictor of mortality after cardiac surgery. This retrospective cohort study was designed to identify the optimal cut-off for baseline serum creatinine (bSCr) and estimated glomerular filtration rate (eGFR) to predict survival. Furthermore, we investigated the potential confounding effect of other perioperative risk indicators on short- and long-term survival. METHODS Data of 9490 cardiac surgical patients were prospectively collected between 1997 and 2008 (follow up to 2010) at the Medical University Vienna. We identified bSCr cut-off values and calculated uni- and multivariate hazard models for short- and long-term survival and compared the results with a validation set from Zurich. The estimated survival curves defined a distinct period of increased mortality until 150 days. RESULTS Cut-off values of >115 µmol litre(-1) for bSCr and ≤50 ml min(-1) for eGFR were identified. Increased bSCr, associated with higher mortality [hazard ratio (HR) 2.61, 95% confidence interval (CI) 2.43-2.80, P<0.0001], was present in 19.5% of patients and remained predictive for short- (HR 1.59, 95% CI 1.38-1.83, P=0.0027) and long-term survival (HR 1.46, 95% CI 1.32-1.62, P<0.0001) in the multivariate hazard models. A cut-off of >120 µmol litre(-1) for bSCr was determined for the validation set. Decreased eGFR was present in 23.6% (HR 2.86, 95% CI 2.67-3.06, P<0.0001). CONCLUSIONS In our patients, increased bSCr was an independent predictor of mortality, which may critically influence risk evaluation and perioperative treatment guidance.

Back-calculating baseline creatinine overestimates prevalence of acute kidney injury with poor sensitivity.

Acute kidney injury (AKI) is diagnosed by a 50% increase in creatinine. For patients without a baseline creatinine measurement, guidelines suggest estimating baseline creatinine by back‐calculation. The aim of this study was to evaluate different glomerular filtration rate (GFR) equations and different GFR assumptions for back‐calculating baseline creatinine as well as the effect on the diagnosis of AKI.

High altitude trekking after lung transplantation: a prospective study using lung ultrasound to detect comets tails for interstitial pulmonary edema in lung transplant recipients and healthy volunteers

The intensity of physical activity which can be tolerated after lung transplantation and the tolerance to prolonged exercise at high altitude are poorly investigated. Lung ultrasound comet tails have been used in the diagnosis of interstitial pulmonary edema and high pulmonary altitude edema. The aim was to assess the number of lung ultrasound comet tails and to monitor changes in the optic nerve sheath diameter (ONSD) during a climb to the top of Mount Kilimanjaro in 10 lung transplant recipients and 10 healthy controls at three different altitude levels: 1360, 3505, 4900 m. Lung transplant recipients showed a constant increase in comet tail scores with altitude, whereas control subjects only showed an increase at the highest measurement point. Differences between groups (transplant versus control) reached significance only after the first ascend: 0.9 (95% CI: −0.41; 2.21) vs. 0.1 (95% CI: −0.12; 0.32) (P = 0.2; 1360 m), 2.33 (95% CI: 0.64; 4.02) vs. 0.3 (95% CI: −0.18; 0.78) (P = 0.04; 3505 m), and 4.11 (95% CI: 0.13; 0.34) vs. 2.9 (95% CI: 0.49; 5.31) (P = 0.15; 4900 m); ONSD increased significantly in both groups from 3.53 (95% CI: 0.34; 0.66) at 1360 m to 4.11 (95% CI: 0.36; 0.71) at 4900 m (P < 0.05). Lungs of transplant recipients are able to adapt to altitude and capable of performing prolonged exercise at high altitude after slow ascend.

Accelerated acute severe antibody-mediated graft failure related to a Ross procedure 17 years earlier†

A 31-year-old male patient underwent a heart transplantation due to dilated cardiomyopathy. He experienced accelerated acute antibody-mediated rejection despite being negative for human leukocyte antigen antibodies (0% panel-reactive antibodies prior to surgery). Further assessment revealed a common antigen between a homograft implanted 17 years earlier during the Ross procedure and the heart donor. The homograft likely induced specific antibody formation. Interestingly, panel-reactive antibody levels measured 7 years prior to transplantation were 7%. Because of the long time span between the Ross procedure and heart transplantation, no circulating antibodies could be detected in 2015, but reactivation of memory cells might potentially have led to this fulminant rejection episode. For future cases, particular attention should be given to patients with homografts.

Minimal changes of serum creatinine in the early postoperative period predict prognosis in patients after cardiac surgery

Preoperative renal insufficiency is an important predictor of mortality after cardiac surgery and the association between small serum creatinine (SCr) changes within 48 hours after cardiac surgery and mortality has been demonstrated. ([1]) Further it has been shown recently that a preoperative elevated SCr is a predictor for worse outcome after cardiac surgery too. ([2])