Optimal hydration volume among high-risk patients with advanced congestive heart failure undergoing coronary angiography

CCTA-Guided Invasive Coronary Angiography in Patients With CABG: A Multicenter, Randomized Study

BACKGROUND

Coronary computed tomography angiography (CCTA) in patients with post-coronary artery bypass graft (CABG) has a high diagnostic accuracy for visualization of grafts. Invasive coronary angiography (ICA) in patients with CABG is associated with increased procedural time, contrast agent administration, radiation exposure, and complications, compared with non-CABG patients. The aim of this multicenter, randomized controlled trial was to compare the strategy of CCTA-guided ICA versus classic ICA in patients with prior CABG.

METHODS

Patients with prior CABG were randomly assigned (1:1 ratio) to have a CCTA before ICA (CCTA-ICA, group A) or not (ICA-only, group B). The primary end point of the study was the total volume (milliliters) of the contrast agent administered.

RESULTS

A total of 251 patients were randomized, and 225 were included in analysis; 110 in group A and 115 in group B. The total contrast volume was higher in group A (184.5 [143-255] versus 154 [102-240] mL; P=0.001). The contrast volume administered during the invasive procedure was lower in group A (101.5 [60-151] versus 154 [102-240]; P<0.001). Total fluoroscopy time was decreased in group A (480 [259-873] versus 594 [360-1080] seconds; P=0.027), but total effective dose was increased (24.1 [17.7-32] versus 10.8 [5.6-18] mSv; P<0.001). The rate of contrast-induced nephropathy, periprocedural complications, and major adverse cardiac events during 3 to 5 and 30 days did not differ significantly between the 2 groups.

CONCLUSIONS

A CCTA-directed ICA strategy for patients with CABG is associated with expedition of the invasive procedure, and less fluoroscopy time, at the cost of higher total contrast volume and effective radiation dose, compared with the classic ICA approach.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04631809.

Key Considerations regarding the Renal Risks of Iodinated Contrast Media: The Nephrologist's Role

BACKGROUND

The administration of iodinated contrast medium during diagnostic and therapeutic procedures has always been associated with the fear of causing acute kidney injury (AKI) or an exacerbation of chronic kidney disease. This has led, on the one hand, to the deterrence, when possible, of the use of contrast medium (preferring other imaging methods with the risk of loss of diagnostic power), and on the other hand, to the trialling of multiple prophylaxis protocols in an attempt to reduce the risk of kidney injury.

SUMMARY

A literature review on contrast-induced (CI)-AKI risk mitigation strategies was performed, focussing on the recognition of individual risk factors and on the most recent evidence regarding prophylaxis.

KEY MESSAGES

Nephrologists can contribute significantly in the CI-AKI context, from the early stages of the decision-making process to stratifying patients by risk, individualising prophylaxis measures based on the risk profile, and ensuring appropriate evaluation of kidney function and damage post-procedure to improve care.

Comparison Between Two Definitions of Contrast-Associated Acute Kidney Injury in Patients With Congestive Heart Failure

Background

Different definitions of contrast-associated acute kidney injury (CA-AKI) have different predictive effects on prognosis. However, few studies explored the relationship between these definitions and long-term prognosis in patients with congestive heart failure (CHF). Thus, we aimed to evaluate this association and compared the population attributable risks (PAR) of different CA-AKI definitions.

Methods

This study enrolled 2,207 consecutive patients with CHF undergoing coronary angiography (CAG) in Guangdong Provincial People's Hospital. Two different definitions of CA-AKI were used: CA-AKI_A was defined as an increase ≥.5 mg/dl or > 25% in serum creatinine (SCr) from baseline within 72 h after CAG, and CA-AKI_B was defined as an increase of ≥.3 mg/dl or > 50% in SCr from baseline within 48 h after CAG. Kaplan-Meier methods and Cox regression were applied to evaluate the association between CA-AKI with long-term mortality. Population attributable risk (PAR) of different definitions for long-term prognosis was also calculated.

Results

During the 3.8-year median follow-up (interquartile range 2.1-6), the overall long-term mortality was 24.9%, and the long-term mortality in patients with the definitions of CA-AKI_A and CA-AKI_B were 30.4% and 34.3%, respectively. We found that CA-AKI_A (HR: 1.44, 95% CI 1.19-1.74) and CA-AKI_B (HR: 1.48, 95% CI 1.21-1.80) were associated with long-term mortality. The PAR was higher for CA-AKI_A (9.6% vs. 8%).

Conclusions

Our findings suggested that CA-AKI was associated with long-term mortality in patients with CHF irrespective of its definitions. The CA-AKI_A was a much better definition of CA-AKI in patients with CHF due to its higher PAR. For these patients, cardiologists should pay more attention to the presence of CA-AKI, especially CA-AKI_A.

Meta-analysis of intravascular volume expansion strategies to prevent contrast-associated acute kidney injury following invasive angiography

OBJECTIVE

To perform a detailed analysis of published data regarding intravascular volume expansion to prevent contrast-associated acute kidney injury (CA-AKI) and to determine if an ideal dose of IV fluids can be recommended.

BACKGROUND

Administration of contrast media during invasive angiography is associated with CA-AKI. Intravascular volume expansion is the most effective intervention to prevent CA-AKI, yet evidenced based protocols are lacking.

METHODS

Literature review and meta-analysis of randomized controlled trials (RCT) of patients receiving IV volume expansion as prophylaxis for CA-AKI was performed. Normal saline, Lactated Ringer's and sodium bicarbonate were included. The primary outcome was incidence of CA-AKI.

RESULTS

37 RCTs studying 12,166 patients were included. Mean age was 67 ± 5 years, 70% of the patients were male. 68% had chronic kidney disease, 41% diabetes, and 30% heart failure. The incidence of CA-AKI was 9.5% (95% CI: 8-12%). IV expansion versus no volume administration was associated with a lower risk of CA-AKI (RR:0.62; 95% CI: 0.49-0.77, p < .001). Intensive IV volume expansion was associated with a reduced risk of CA-AKI(RR: 0.66; 95%CI: 0.52-0.85, p < .01). The intensive IV volume expansion arm received significantly more fluids than the standard protocols: 1,574(1,123 - 1,913) ml versus 849(558-1,067) ml (p = .03) without significant difference in the duration of infusion (median of 12 vs. 17 hr, p = .1) or pulmonary edema (1.7% vs 1.3%, p = .7).

CONCLUSIONS

Despite high variability in protocols used, IV volume expansion is effective in preventing CA-AKI. Intensive IVF expansion (median 1.6 L over 17 hr) was associated with decreased risk of CA-AKI.

Association of the classification and severity of heart failure with the incidence of contrast-induced acute kidney injury

Congestive heart failure (HF) is a known risk factor of contrast-induced acute kidney injury (CI-AKI). However, the relationship of the classification and severity of HF with CI-AKI remains under-explored. From January 2009 to April 2019, we recruited patients undergoing elective PCI who had complete pre- and post-operative creatinine data. According to the levels of ejection fraction (EF), HF was classified as HF with reduced EF (HFrEF) [EF < 40%], HF with mid-range EF (HFmrEF) [EF 40–49%] and HF with preserved EF (HFpEF) [EF ≥ 50%]. CI-AKI was defined as an increase of either 25% or 0.5 mg/dL (44.2 μmoI/L) in serum baseline creatinine level within 72 h following the administration of the contrast agent. A total of 3848 patients were included in the study; mean age 67 years old, 33.9% females, 48.1% with HF, and 16.9% with CI-AKI. In multivariate logistic regression analysis, HF was an independent risk factor for CI-AKI (OR 1.316, p value < 0.05). Among patients with HF, decreased levels of EF (OR 0.985, p value < 0.05) and elevated levels of N-terminal pro b-type natriuretic peptide (NT-proBNP) (OR 1.168, p value < 0.05) were risk factors for CI-AKI. These results were consistent in subgroup analysis. Patients with HFrEF were more likely to develop CI-AKI than those with HFmrEF or HFpEF (OR 0.852, p value = 0.031). Additionally, lower levels of EF were risk factors for CI-AKI in the HFrEF and HFmrEF groups, but not in the HFpEF group. NT-proBNP was an independent risk factor for CI-AKI in the HFrEF, HFmrEF and HFpEF groups. Elevated levels of NT-proBNP are independent risk factors for CI-AKI irrespective of the classification of HF. Lower levels of EF were risk factors for CI-AKI in the HFrEF and HFmrEF groups, but not in the HFpEF group.

Renin-angiotensin-aldosterone system inhibition decreased contrast-associated acute kidney injury in chronic kidney disease patients

BACKGROUND/PURPOSE

Chronic kidney disease (CKD) is a risk factor for contrast associated acute kidney injury (CA-AKI). The risk of renin-angiotensin-aldosterone system inhibitor (RASi) use in patients with CKD before the administration of contrast is not clear.

METHODS

In this nested case-control study, 8668 patients received contrast computed tomography (CT) from 2013 to 2018 during index administration in a multicenter hospital cohort. The identification of AKI is based on the Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria within 48 h after contrast medium used.

RESULTS

Finally, 986 patients (age, 63.36 ± 12.22; men, 72.92%) with CKD (estimated glomerular filtration rate (eGFR) = 35.0 ± 19.8 mL/min/1.73 m²) were eligible for analysis. After the index date, RASi users (n = 315) were less likely to develop CA-AKI (13.65% vs 30.4%, p < 0.001), and had a lower hospital mortality (8.25% vs 19.23%, p < 0.001) compared with non-users. The pre-contrast use of RASi decrease the risk of AKI (OR, 0.342, p < 0.001) and hospital mortality (OR, 0.602, p = 0.045). Even a few defined daily doses (DDDs) of RASi treatment, more than 0.02 prior to contrast CT could attenuate CA-AKI. The hospital mortality was higher in RASi non-users if their eGFR value was more than 17.9 mL/min/1.73 m².

CONCLUSION

RASi use in patients with CKD prior to contrast CT has the potential to mitigate the incidence of AKI and hospital mortality. Even a low dose of RASi will noticeably decrease the risk of AKI and will not increase the risk of hyperkalemia.

Practical guide to prevention of contrast-induced acute kidney injury after percutaneous coronary intervention

Contrast-induced acute kidney injury (CI-AKI) represents a common but serious complication of percutaneous coronary interventions (PCI)-and in general of all those examinations requiring iodinated contrast injection-which affects not only renal function but also long-term prognosis. While several prophylactic approaches were designed in order to prevent CI-AKI, most failed to demonstrate clear benefits in randomized trials, and their implementation is therefore discouraged in clinical practice. The most notorious examples include pre-procedural bicarbonate or N-acetylcysteine, and preprocedural withdrawal of ACE inhibitors/Angiotensin receptor blockers. Those strategies that were instead demonstrated effective include the appropriate use of preprocedural hydration, reduction in contrast volume utilization, adoption of techniques for zero- or ultra-low-contrast procedures, and pharmacological treatments with statins. In this brief review, we summarize the main preventive strategies into brief and pragmatic recommendations designed to improve everyday clinical practice.

Contrast Induced Acute Kidney Injury and Direct Cytotoxicity of Iodinated Radiocontrast Media on Renal Proximal Tubule Cells

The administration of intravenous iodinated radiocontrast media (RCM) to visualize internal structures during diagnostic procedures has increased exponentially since their first use in 1928. A serious side effect of RCM exposure is contrast-induced acute kidney injury (CI-AKI), which is defined as an abrupt and prolonged decline in renal function occurring 48-72 hours after injection. Multiple attempts have been made to decrease the toxicity of RCM by altering ionic strength and osmolarity, yet there is little evidence to substantiate that a specific RCM is superior in avoiding CI-AKI. RCM-associated kidney dysfunction is largely attributed to alterations in renal hemodynamics, specifically renal vasoconstriction; however, numerous studies indicate direct cytotoxicity as a source of epithelial damage. Exposure of in vitro renal proximal tubule cells to RCM has been shown to affect proximal tubule epithelium in the following manner: 1) changes to cellular morphology in the form of vacuolization; 2) increased production of reactive oxygen species, resulting in oxidative stress; 3) mitochondrial dysfunction, resulting in decreased efficiency of the electron transport chain and ATP production; 4) perturbation of the protein folding capacity of the endoplasmic reticulum (ER) (activating the unfolded protein response and inducing ER stress); and 5) decreased activity of cell survival kinases. The present review focuses on the direct cytotoxicity of RCM on proximal tubule cells in the absence of in vivo complications, such as alterations in renal hemodynamics or cytokine influence.