Poor Agreement Between Preoperative Transthoracic Echocardiography and Intraoperative Transesophageal Echocardiography for Grading Diastolic Dysfunction.

BACKGROUND: Guidelines for the evaluation and grading of diastolic dysfunction are available for transthoracic echocardiography (TTE). Transesophageal echocardiography (TEE) is used for this purpose intraoperatively but the level of agreement between these 2 imaging modalities for grading diastolic dysfunction is unknown. We assessed agreement between awake preoperative TTE and intraoperative TEE for grading diastolic dysfunction. METHODS: In 98 patients undergoing cardiac surgery, key Doppler measurements were obtained using TTE and TEE at the following time points: TTE before anesthesia induction (TTEawake), TTE following anesthesia induction (TTEanesth), and TEE following anesthesia induction (TEEanesth). The primary endpoint was grade of diastolic dysfunction categorized by a simplified algorithm, and measured by TTEawake and TEEanesth, for which the weighted κ statistic assessed observed agreement beyond chance. Secondary endpoints were peak early diastolic lateral mitral annular tissue velocity (e'lat) and the ratio of peak early diastolic mitral inflow velocity (E) to e'lat (E/e'lat), measured by TTEawake and TEEanesth, were compared using Bland-Altman limits of agreement. RESULTS: Disagreement in grading diastolic dysfunction by ≥1 grade occurred in 43 (54%) of 79 patients and by ≥2 grades in 8 (10%) patients with paired measurements for analysis, yielding a weighted κ of 0.35 (95% confidence interval [CI], 0.19-0.51) for the observed level of agreement beyond chance. Bland-Altman analysis of paired data for e'lat and E/e'lat demonstrated a mean difference (95% CI) of 0.51 (-0.06 to 1.09) and 0.70 (0.07-1.34), respectively, for measurements made by TTEawake compared to TEEanesth. The percentage (95% CI) of paired measurements for e'lat and E/e'lat that lay outside the [-2, +2] study-specified boundary of acceptable agreement was 36% (27%-48%) and 39% (29%-51%), respectively. Results were generally robust to sensitivity analyses, including comparing measurements between TTEawake and TTEanesth, between TTEanesth and TEEanesth, and after regrading diastolic dysfunction by the American Society of Echocardiography (ASE)/European Association of CardioVascular Imaging (EACVI) algorithm. CONCLUSIONS: There was poor agreement between TTEawake and TEEanesth for grading diastolic dysfunction by a simplified algorithm, with disagreement by ≥1 grade in 54% and by ≥2 grades in 10% of the evaluable cohort. Future studies, including comparing the prognostic utility of TTEawake and TEEanesth for clinically important adverse outcomes that may be a consequence of diastolic dysfunction, are needed to understand whether this disagreement reflects random variability in Doppler variables, misclassification by the changed technique and physiological conditions of intraoperative TEE, or the accurate detection of a clinically relevant change in diastolic dysfunction.

Is an Acute Perioperative Increase in Creatinine Production Rate a Potential Mechanism for an Early Creatinine-Based Signal of Renal Injury After Cardiac Surgery?

OBJECTIVES: Previous studies report a creatinine-based signal of injury within hours after cardiac surgery, which is sooner than expected based on creatinine kinetic modelling. A plausible mechanism for such an early signal has not been established, but might be explained by an acute perioperative increase in creatinine production rate (Crprod-rate). The authors sought to test the hypothesis that perioperative Crprod-rate increases from baseline in patients undergoing cardiac surgery. DESIGN: Prospective cohort study. SETTING: Academic medical center. PARTICIPANTS: Fifty adult male patients undergoing cardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Based on the principle of conservation of mass, precisely timed serial measurements of patient weight, plasma and urine creatinine concentration, and urine volume were used to calculate Crprod-rate over 3 consecutive periods: a baseline period immediately before surgery (period 0), the 24-hour period starting from induction of anesthesia (period 1), and again from 24 to 48 hours after induction of anesthesia (period 2). The primary outcome was change in Crprod-rate from period 0 to period 1 (∆Crprod-rate0-1). Median Crprod-rate0 was 5.4 (interquartile range [IQR], 4.7-5.7) µmol/kg/h at baseline and increased to 6.1 (IQR, 5.6-6.5) µmol/kg/h during period 1, a median increase of 14% (95% CI, 8%-27%; p = 0.002). ∆Crprod-rate0-1 ranged from -58% to +129%, with an increase above baseline in 25 patients (76%) and an increase by ≥30% above baseline in 10 patients (30%). CONCLUSIONS: Perioperative Crprod-rate increased from baseline in patients undergoing cardiac surgery. This may represent a mechanism for an earlier creatinine-based signal of renal injury than previously thought possible.