Differential Release Kinetics of Cardiac Biomarkers in Patients Undergoing Valve Replacement Surgery

Impact of underlying heart disease per se on the utility of preoperative NT-proBNP in adult cardiac surgery

Objective

The primary aim was to investigate the role of underlying heart disease on preoperative NT-proBNP levels in patients admitted for adult cardiac surgery, after adjusting for the known confounders age, gender, obesity and renal function. The second aim was to investigate the predictive value of preoperative NT-proBNP with regard to severe postoperative heart failure (SPHF) and postoperative mortality.

Methods

A retrospective cohort study based on preoperative NT-proBNP measurements in an unselected cohort including all patients undergoing first time surgery for coronary artery disease (CAD; n = 2226), aortic stenosis (AS; n = 406) or mitral regurgitation (MR; n = 346) from April 2010 to August 2016 in the southeast region of Sweden (n = 2978). Concomitant procedures were not included, with the exception of Maze or tricuspid valve procedures.

Results

Preoperative NT-proBNP was 1.67 times (p<0.0001) and 1.41 times (p<0.0001) higher in patients with AS or MR respectively, than in patients with CAD after adjusting for confounders.

NT-proBNP demonstrated significant discrimination with regard to SPHF in CAD (AUC = 0.79, 95%CI 0.73–0.85, p<0.0001), MR (AUC = 0.80, 95%CI 0.72–0.87, p<0.0001) and AS (AUC = 0.66, 95%CI 0.51–0.81, p = 0.047). In CAD patients NT-proBNP demonstrated significant discrimination with regard to postoperative 30-day or in-hospital mortality (AUC = 0.78; 95%CI 0.71–0.85, p<0.0001). The number of deaths was too few in the AS and MR group to permit analysis. Elevated NT-proBNP emerged as an independent risk factor for SPHF, and postoperative mortality in CAD.

Conclusions

Patients with AS or MR have higher preoperative NT-proBNP than CAD patients even after adjusting for confounders. The predictive value of NT-proBNP with regard to SPHF was confirmed in CAD and MR patients but was less convincing in AS patients.

Association of cardiac biomarkers with acute kidney injury after cardiac surgery: A multicenter cohort study

OBJECTIVE

Acute kidney injury is common after cardiac surgery and associated with postoperative mortality. Perioperative cardiac biomarkers may predict acute kidney injury and mortality. We evaluated whether cardiac biomarkers were associated with severe acute kidney injury, defined as a doubling in serum creatinine or requiring renal replacement therapy during hospital stay after surgery, and mortality.

METHODS

In a prospective multicenter cohort of adults undergoing cardiac surgery, we measured the following biomarkers in preoperative and postoperative banked plasma: high-sensitivity troponin T, cardiac troponin I, creatine kinase-MB, and N-terminal prohormone of brain natriuretic peptide.

RESULTS

In the patients who were discharged alive, severe acute kidney injury occurred in 37 of 960 (3.9%), and 43 of 960 (4.5%) died within 1 year of follow-up. N-terminal prohormone of brain natriuretic peptide was the only preoperative biomarker that was independently associated with severe acute kidney injury (with log transformation, adjusted odds ratio, 1.4; 95% confidence interval, 1.0-1.9). Biomarkers measured within 6 hours of surgery (day 1) were all associated with severe acute kidney injury. Preoperative N-terminal prohormone of brain natriuretic peptide was also independently associated with 1-year mortality (with log transformation, adjusted odds ratio, 1.7; 95% confidence interval, 1.2-2.2). Patients in the highest tertile for N-terminal prohormone of brain natriuretic peptide preoperatively (>1006.4 ng/L) had marked increases in their risk for 1-year mortality (adjusted odds ratio, 27.2; 95% confidence interval, 3.5-213.5). Day 1 N-terminal prohormone of brain natriuretic peptide was associated with mortality independently of change in serum creatinine from preoperative baseline.

CONCLUSIONS

Of the studied biomarkers, N-terminal prohormone of brain natriuretic peptide was the only preoperative biomarker independently associated with severe acute kidney injury and mortality. Early increases in postoperative cardiac biomarkers were associated with severe acute kidney injury after cardiac surgery. Future research should focus on whether interventions that lower N-terminal prohormone of brain natriuretic peptide can affect postoperative outcomes.

The Use of Lidocaine Containing Cardioplegia in Surgery for Adult Acquired Heart Disease

BACKGROUND

Del Nido cardioplegia, a crystalloid-based solution with lidocaine as a key element, is given as a single dose and has been used successfully in congenital cardiac surgery.

HYPOTHESIS

We retrospectively compared a lidocaine containing "modified del Nido" solution with our standard whole blood cardioplegia to investigate its safety and efficacy in adult cardiac surgery.

METHODS

From June 1, 2013 to December 30, 2013, we used a single dose of lidocaine containing cardioplegia (LC group) in 92 consecutive operations. Propensity matching analysis was undertaken to compare the outcomes of such patients with those who underwent their surgery by the same surgeon using standard whole blood cardioplegia (WB group), n = 396. Propensity score matching yielded 79 pairs of patients.

RESULTS

After propensity matching, LC and WB groups were similar in baseline operative characteristics including cross-clamp time (LC: 65 minutes [range 54 to 89] vs. WB: 70 minutes [54 to 86], p = 0.993). Postoperative outcomes were similar including inotropic requirements (30.4% [24/72] vs. 25.3% [20/72], p < 0.60), median ventilation time (4.7 hours vs. 5.3, p < 0.74) and median length of stay was seven days for both groups (p < 0.82). Despite higher median postoperative, 24-hour CK-MB levels LC group (LC:22.3 ng/ml, range [15.6 to 40.3] vs. WB:18.4 ng/ml [13.9 to 28.2], p = 0.040), operative and one-year mortality were comparable among study groups (both p > 0.798).

CONCLUSIONS

Lidocaine containing cardioplegia appears to be safe in adults undergoing cardiac procedure when administered for the first 60 minutes of aortic cross clamping. Higher CK-MB levels did not translate into adverse clinical outcomes.