Usefulness of Preoperative Echocardiography to Predict Acute Kidney Injury and Long-Term Mortality After Coronary Artery Bypass Grafting

Predictive Value of the Transthoracic Echocardiography Index for Acute Kidney Injury after Cardiac Valve Surgery

Background: We aimed to demonstrate whether the preoperative transthoracic echocardiography index (TTEI) could improve the predictive value of clinical parameters for cardiac valve surgery-associated acute kidney injury (CVS−AKI). Methods: A total of 213 patients who underwent surgical CVS at Renmin Hospital of Wuhan University were consecutively recruited in this retrospective study. TTE assessments were performed within 7 days before surgery and logistic regression was used to determine TTEI. A nomogram was constructed by integrating TTEI and clinical features, and the net reclassification index (NRI) and integrated discrimination improvement (IDI) were applied to evaluate the improvement in TTEI for CVS−AKI. Results: Among them, 66 patients (30.9%) developed CVS−AKI. The TTEI was calculated as follows: −6.579 + 0.068 × pulmonary artery systolic pressure (mmHg) −0.742 × LVEF (>55%, yes or no) + 0.346 × left ventricle posterior wall thickness (mm). The nomogram based on the TEEI and other clinical factors possessed excellent performance (C-index = 0.880), had great calibration and discrimination, and was clinically useful. Furthermore, NRI (0.07, 95% confidence interval, 95%CI, 0.01−0.12, p = 0.02) and IDI (0.08, 95%CI, 0.01−0.20, p = 0.02) indicated that TTEI could significantly improve the predictive value of clinical features for CVS−AKI. Conclusions: As a simple access and cost-effective parameter, the preoperative TTEI may be a reliable and useful factor for CVS−AKI.

Prognostic implications of N-terminal pro-B-type natriuretic peptide in patients with normal left ventricular ejection fraction undergoing transcatheter aortic valve implantation

BACKGROUND

Biomarkers may significantly improve risk stratification algorithms for patients undergoing transcatheter aortic valve implantation (TAVI). While N-terminal pro-B-type natriuretic peptide (NT-proBNP) is established as a biomarker in the context of heart failure, its prognostic implications in patients with normal left ventricular ejection fraction (LVEF) undergoing TAVI are unclear.

METHODS

A total of 504 TAVI patients with normal LVEF were analyzed. Based on preprocedural NT-proBNP levels, patients were stratified into two groups comparing the upper quartile ("Q4", n = 126) with the lower three quartiles ("Q1-3", n = 378). The primary outcome of our study was survival.

RESULTS

The "Q4" group included more men (46.8% vs. 34.9%, p = 0.017), had higher rates of atrial fibrillation (55.6% vs. 28.3%, p < 0.001) and showed features of more advanced aortic stenosis (mean pressure gradient 49 mmHg vs. 40 mmHg, aortic valve area 0.6 cm² vs. 0.7 cm²; p < 0.001, respectively). The "Q4" group was also characterized by more extensive cardiac remodeling including severe diastolic dysfunction (18.1% vs. 6.5%, p < 0.001) and left atrial dilation (26.8% vs. 10.8%, p < 0.001). Kaplan-Meier analysis demonstrated superior survival of the "Q1-3" group (median follow-up 22.1 months, log-rank test p < 0.001). In a multivariable analysis, preprocedural NT-proBNP emerged as a significant risk factor for all-cause mortality after TAVI (HR 1.87, CI 1.31-2.65, p < 0.001).

CONCLUSIONS

NT-proBNP is associated with survival in TAVI patients with normal LVEF. In this patient group, preprocedural NT-proBNP levels do not only correlate with aortic stenosis, but reflect advanced cardiovascular dysfunction, including HFpEF, that might not be completely reversible after TAVI.

Diastolic dysfunction and acute kidney injury in elderly patients with femoral neck fracture

Background

Femoral neck fracture is common in the elderly population. Acute kidney injury (AKI) is an important risk factor for mortality in patients who have had such fracture. We evaluated the incidence of AKI in patients who had femoral neck fracture and identified risk factors for AKI and mortality.

Methods

This was an observational cohort study including 285 patients who were ≥ 65 years of age and who underwent femoral neck fracture surgery between 2013 and 2017.

Results

The mean age was 78.63 ± 6.75 years. A total of 67 (23.5%) patients developed AKI during the hospital stay: 57 (85.1%), 5 (7.5%), and 5 (7.5%) patients were classified as having stage 1, 2, and 3 AKI, respectively. Patients with AKI had a lower baseline estimated glomerular filtration rate and higher left atrial dimension, left ventricular mass index, pulmonary artery pressure, and the ratio of early mitral inflow velocity to early diastolic mitral annulus velocity (E/e’) and were more likely to have diabetes or hypertension (HTN) (P < 0.05). The presence of HTN (odds ratio [OR], 4.570; 95% confidence interval [CI], 1.632–12.797) higher E/e’ (OR, 1.105; 95% CI, 1.019–1.198), and lower hemoglobin (OR, 0.704; 95% CI, 0.528–0.938) were independently associated with a higher risk for developing AKI. Severe AKI (OR, 24.743; 95% CI, 2.822–212.401) was associated with a higher risk of mortality.

Conclusion

Elderly patients with femoral neck fracture had a high incidence of AKI. Diastolic dysfunction was associated with AKI. Severe AKI was associated with in-hospital mortality.

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.

Perioperative Echocardiographic Index of Left Ventricular Filling Pressure in Cardiac Surgery

BACKGROUND

The elevated preoperative ratio of early transmitral flow velocity to early diastolic velocity of the mitral annulus (E/e') as an echocardiographic index of left ventricular filling pressure is known to be associated with poor postoperative outcomes. We investigated the association between preoperative and postoperative E/e' elevation and clinical outcomes after cardiac operations.

METHODS

The study divided 1,353 patients who underwent cardiac operations into four groups: preoperative and postoperative E/e' ≤15 (low-low), preoperative E/e' ≤15 but postoperative E/e' >15 (low-high), preoperative E/e' >15 but postoperative E/e' ≤15 (high-low), and preoperative and postoperative E/e' >15 (high-high). Cox proportional hazard analysis was performed. Kaplan-Meier curve analysis was performed before and after propensity score matching.

RESULTS

The four perioperative E/e' categories were independently associated with 5-year mortality (hazard ratio, high-high vs low-low: 3.58; low-high vs low-low: 3.75; high-low vs low-low: 1.18). Kaplan-Meier curves showed that mortality was significantly different between the groups (log-rank test: high-high vs. low-low, p < 0.001; low-high vs low-low, p < 0.001). Postoperative intensive care unit and hospital lengths of stay, incidence of acute kidney injury, and 1-year mortality were significantly different. However, after propensity score matching, mortality and the incidence of postoperative acute kidney injury were significantly different only between postoperative E/e' ≤15 and E/e' >15, but not between preoperative E/e' ≤15 and E/e' >15.

CONCLUSIONS

Postoperative E/e' >15 was more strongly associated with mortality and acute kidney injury than preoperative E/e' >15. Measurement of the postoperative E/e' ratio may help in assessing the risk of these patients.

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.