Association Between Left Ventricular Relative Wall Thickness and Acute Kidney Injury After Noncardiac Surgery

Fine-Mapping the Association of Acute Kidney Injury With Mean Arterial and Central Venous Pressures During Coronary Artery Bypass Surgery

BACKGROUND

Prior studies identified thresholds for mean arterial pressure (MAP <65 mm Hg) and central venous pressure (CVP >12 mm Hg) beyond which risk for cardiac surgery-associated acute kidney injury (AKI) increases. Optimal hemodynamic targets-that is, where active protection from AKI is observed-are unclear; however, current guidelines suggest maintaining MAP >65 and CVP 8 to 12. The aim of this study was to identify hemodynamic ranges associated with both increased and decreased risk of AKI by evaluating narrow ranges of MAP, CVP, and joint exposure to MAP and CVP concurrently.

METHODS

In a retrospective cohort study of adults undergoing coronary artery bypass surgery, we fine-mapped the association between AKI and the total number of minutes spent in each of the following narrow hemodynamic ranges: 14 MAP ranges in increments of 5 mm Hg (45-115), 10 CVP ranges in increments of 2 mm Hg (0-20), and 70 joint MAP/CVP ranges. Separate multivariable regression models estimated adjusted odds ratios (aOR) for each range including adjustments for correlations and multiple comparisons across ranges. Joint MAP/CVP ranges were grouped into 5 hemodynamic zones based on contiguity of the ranges and similarity of ORs observed across ranges in a color-coded heatmap. The 5 MAP/CVP zones were included in a single regression model to assess risk for AKI associated with time spent in each hemodynamic zone, independent of time spent in other zones.

RESULTS

In 1199 participants, incidence of AKI was 28%. For every 5-minute spent in each hemodynamic range, risk of AKI was significantly increased in MAP range 45 to 50 (aOR 1.18; P = .002), 50 to 55 (aOR 1.13; P = .001), and 55 to 60 mm Hg (aOR 1.06; P = .001); and significantly decreased in MAP range 90 to 95 mm Hg (aOR 0.85; P <.001). Risk of AKI was significantly increased in CVP range 16 to 18 mm Hg (aOR 1.07; P = .002) and significantly decreased in CVP range 4 to 6 mm Hg (aOR 0.97; P = .025). In joint analyses, both MAP and CVP contributed to AKI risk estimates; risk decreased as CVP decreased within every MAP range and was significantly lower for joint ranges of CVP <8 and MAP >75. In analyses containing all 5 MAP/CVP hemodynamic zones, risk estimates suggested protection from AKI in zone 1 (high MAP/low CVP) and increased risk of AKI in zones 3 to 5 (low MAP/high CVP).

CONCLUSIONS

Fine-mapping identified narrow ranges of MAP, CVP, and joint MAP/CVP associated with both AKI risk and protection. This report is among the first to characterize the association between joint MAP/CVP and AKI. Contrary to current guidelines, there was no evidence for protection associated with MAP 65 to 75 or CVP 8 to 12 mm Hg.

Association between Left Ventricular Geometry, Systolic Ejection Time, and Estimated Glomerular Filtration Rate in Ambulatory Patients with Preserved Left Ventricular Ejection Fraction

INTRODUCTION

Cardiac function is important to quantify for risk stratification. Although left ventricular ejection fraction (LVEF) is commonly used, and identifies patients with poor systolic function, other easily acquired measures of cardiac function are needed, particularly to stratify patients with relatively preserved LVEF. LV relative wall thickness (RWT) has been associated with adverse clinical outcomes in patients with preserved LVEF, but the clinical relevance of this observation is not known. The purpose of this study was to assess whether increased RWT is a marker of subclinical cardiac dysfunction as measured by a surrogate of LV dysfunction and left ventricular ejection time (LVET) and if increased RWT is independently associated with chronic kidney disease (CKD), an important clinical outcome and cardiovascular disease risk equivalent.

METHODS

This retrospective cohort study enrolled ambulatory patients 18 years and older undergoing routine transthoracic echocardiography (TTE) at Johns Hopkins Hospital from January 2017 to January 2018. Patients with LVEF <50%, severe valvular disease, or liver failure were excluded. Multivariable regression evaluated the relationship between RWT, LVET, and CKD adjusted for demographics, comorbidities, and vital signs.

RESULTS

We analyzed data from 375 patients with mean age (±SD) 52.2 ± 15.3 years of whom 58% were female. Mean ± SD of RWT was 0.45 ± 0.10, while mean ± SD of LVET was 270 ms ± 33. In multivariable linear regression adjusted for demographics, comorbidities, vital signs, and left ventricular mass, each 0.1 increase in RWT was associated with a decrease of 4.6 ms in LVET, indicating worse cardiac function (β, ± 95% CI) (-4.60, -7.37 to -1.48, p = 0.004). Of those with serum creatinine available 1 month before or after TTE, 20% (50/247) had stage 3 or greater CKD. In logistic regression (adjusted for sex, comorbidities, and medications), each 0.1 unit increase in RWT was associated with an 61% increased odds of CKD (aOR = 1.61, 1.03-2.53, p = 0.037). In multivariable ordinal regression adjusted for the same covariates, each 0.1 unit increase in RWT was associated with a 44% increased odds of higher CKD stage (aOR = 1.44, 1.03-2.02, p = 0.035). There was a trend but no statistically significant relationship between RWT and change in estimated glomerular filtration rate at 1 year.

CONCLUSION

In an outpatient cohort undergoing TTE, increased RWT was independently associated with a surrogate of subclinical systolic dysfunction (LVET) and CKD. This suggests that RWT, an easily derived measure of LV geometry on TTE, may identify clinically relevant subclinical systolic dysfunction and patients with worse kidney function. Additional investigation to further clarify the relationships between RWT, systolic function, and kidney dysfunction over time and how this information may guide clinical intervention are warranted.

Cardiac remodeling on echocardiogram is related to contrast-associated acute kidney injury after coronary angiography: a cross-section study

Background

Cardiac dysfunction is a well-established risk factor for contrast-associated acute kidney injury (CA-AKI). Nevertheless, the relationship between cardiac remodeling, as assessed by echocardiography, and CA-AKI remains uncertain.

Method

A total of 3,241 patients undergoing coronary angiography (CAG) with/without percutaneous coronary intervention (PCI) were enrolled in this retrospective study. Collected echocardiographic parameters were normalized by body surface area (BSA) and divided according to quartile, including the left ventricular internal end-diastolic diameter index (LVIDDI), left ventricular internal end-systolic diameter index (LVIDSI), and left ventricular mass index (LVMI). Logistic regression analysis was conducted to ascertain the association between structural parameter changes and CA-AKI. Further investigation was performed in different subgroups.

Results

The mean age of the participants was 66.6 years, and 16.3% suffered from CA-AKI. LVIDSI [≥22.9 mm/m2: OR = 1.953, 95%CI (1.459 to 2.615), P < 0.001], LVIDDI [≥33.2 mm/m2: OR = 1.443, 95%CI (1.087 to 1.914), P = 0.011], and LVMI [≥141.0 g/m2: OR = 1.530, 95%CI (1.146 to 2.044), P = 0.004] in quartile were positively associated with CA-AKI risk in general (all P for trend <0.05). These associations were consistent when stratified by age, left ventricular ejection fraction, estimated glomerular filtration rate, and N-terminal brain natriuretic peptide (all P for interaction >0.05). The presence of eccentric hypertrophy [OR = 1.400, 95%CI (1.093 to 1.793), P = 0.008] and the coexistence of hypertrophy and dilation [OR = 1.397, 95%CI (1.091 to 1.789), P = 0.008] carried a higher CA-AKI risk.

Conclusion

The presence of cardiac remodeling, assessed by echocardiography, is associated with a higher risk of CA-AKI.

Preoperative Evaluation and Cardiac Risk Assessment in Vascular Surgery

We summarize epidemiologic trends, outcomes, and preoperative guidelines for vascular surgery patients from 2010 to 2022. Vascular surgery continues to evolve in technology and engineering to treat a surgical population that suffers from a high prevalence of comorbidities. Preoperative optimization seeks to characterize the burden of disease and to achieve medical control in the timeline available before surgery. Risk assessment, evaluation, optimization, and prediction of major adverse cardiac events is an evolving science where the Vascular Surgery Quality Initiative has made an impact. Ongoing investigation may demonstrate value for preoperative echocardiography, functional capacity, frailty, and mobility assessments.