Atherosclerosis burden of the aortic valve and aorta and risk of acute kidney injury after transcatheter aortic valve implantation

The Predictive Value of Aortic Calcification on Computed Tomography for Major Cardiovascular Events

As the prevalence of cardiovascular disease continues to increase, early identification of patients at high risk of major adverse cardiovascular events (MACE) using reliable diagnostic modalities is important. Transcatheter aortic valve implantation (TAVI) is a minimally invasive percutaneous procedure used to replace the aortic valve with a bioprosthetic one, often without the need for surgery. Extra coronary calcification in the ascending and/or descending thoracic aorta, aortic arch, and abdominal aorta has recently been identified as a method to quantify the extent of atherosclerotic cardiovascular disease. However, its definitive role in the prediction of MACE remains unclear. We performed a comprehensive review to summarize the current literature on the diagnostic and predictive value of thoracic and abdominal aortic calcification, as quantified in computed tomography, for the association, risk stratification, and prediction of MACE and after TAVI procedures. Despite increasing evidence, the predictive role of thoracic calcification still remains unproven, with a need for carefully tailored studies to confirm these findings.

Factors Associated With Acute Kidney Injury in Patients Undergoing Transcatheter Aortic Valve Implantation: A Systematic Review and Meta-Analysis

The aim of this meta-analysis is to assess the effect of different independent predictors on acute kidney injury (AKI) after transcatheter aortic valve implantation (TAVI). This meta-analysis adhered to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A comprehensive database search was conducted using PubMed, Web of Science, and Scopus for the period from January 1, 2015, to August 15, 2023. The following key terms were employed: "transcatheter aortic valve implantation" OR "transcatheter aortic valve replacement" AND "acute kidney injury" OR "acute renal failure." Our search was limited to studies published exclusively in the English language. The statistical analysis was conducted using RevMan version 5.4.1 (The Cochrane Collaboration). Estimates were presented as odds ratio (OR) with 95% confidence interval (CI) for categorical variables, while continuous variables were reported as mean difference (MD) with 95% CI. A total of 19 studies met the selection criteria and were included in the meta-analysis. The pooled incidence of AKI was reported as 20% (95% CI: 18-20%). Factors significantly associated with post-TAVI AKI encompass hypertension, chronic kidney disease (CKD), low estimated glomerular filtration rate (eGFR), high baseline creatinine levels, peripheral vascular disease (PVD), Society of Thoracic Surgeons (STS) score, European System for Cardiac Operative Risk Evaluation (EUROscore) II, and the transfemoral surgical approach.

Supra-renal aortic atheroma extent and composition predict acute kidney injury after transcatheter aortic valve replacement: A three-dimensional computed tomography study

OBJECTIVE

Acute kidney injury (AKI) may complicate transcatheter aortic valve replacement (TAVR) and could be linked to atheroembolization associated with catheter manipulation in the supra-renal (SR) aorta. We sought to determine the impact of SR aortic atheroma burden (SR-AAB) and composition, as well as of the aortic valve calcium score (AV-CS), measured at pre-operative multislice computed tomography (PO-MSCT), on AKI-TAVR.

METHODS

All TAVR-patients 3 January-2018 to December-2020 were included. A three-dimensional analysis of PO-MSCT was performed, calculating percentage SR-AAB (%SR-AAB) as [(absolute SR-AAB volume)*100/vessel volume]. Types of plaque were defined according to Hounsfield unit (HU) intensity ranges. Calcified plaque was subcategorized into 3 strata: low- (351-700 HU), mid- (701-1000 HU), and high‑calcium (>1000 HU, termed 1 K-plaque).

RESULTS

The study population included 222 patients [mean age 83.3 ± 5.7 years, 95 (42.8%) males], AKI-TAVR occurred in 67/222 (30.2%). Absolute SR-AAB (41.3 ± 16.4 cm³ vs. 32.5 ± 10.7 cm³,p < 0.001) and %SR-AAB (17.6 ± 5.1% vs. 13.9 ± 4.3%,p < 0.001) were significantly higher in patients developing AKI-TAVR. Patients who developed AKI-TAVR had higher mid‑calcium (6.9 ± 3.8% vs. 4.2 ± 3.5%,p < 0.001) and 1 K-plaque (5.4 ± 3.7% vs. 2.4 ± 2.4%,p < 0.001) with no difference in AV-CS (p = 0.691). Adjusted multivariable logistic regression analysis showed that %SR-AAB [OR (x%increase): 1.12, 95%CI: 1.04-1.22,p = 0.006] and %SR-calcified plaque [OR (x%increase): 5.60, 95%CI: 2.50-13.36,p < 0.001] were associated with AKI-TAVR. Finally, 3-knots spline analyses identified %SR-AAB >15.0% and %SR-calcified plaque >7.0% as optimal thresholds to predict an increased risk of AKI-TAVR.

CONCLUSIONS

Suprarenal aortic atheroma, when highly calcified, is associated with AKI-TAVR. Perioperative-MSCT assessment of aortic atherosclerosis may help in identification of patients at high-risk for AKI-TAVR, who could benefit from higher peri-operative surveillance.

Transcatheter Aortic Valve Replacement-Associated Acute Kidney Injury: An Update

BACKGROUND

Transcatheter aortic valve replacement (TAVR) is a relatively novel minimally invasive procedure for the treatment of symptomatic patients with severe aortic stenosis. Although it has been proven effective in improving mortality and quality of life, TAVR is associated with serious complications, such as acute kidney injury (AKI).

SUMMARY

TAVR-associated AKI is likely due to several factors such as sustained hypotension, transapical approach, volume of contrast use, and baseline low GFR. This narrative review aims to present an overview of the latest literature and evidence regarding the definition of TAVR-associated AKI, its risk factors, and its impact on morbidity and mortality. The review used a systematic search strategy with multiple health-focused databases (Medline, EMBASE) and identified 8 clinical trials and 27 observational studies concerning TAVR-associated AKI. Results showed that TAVR-associated AKI is linked to several modifiable and nonmodifiable risk factors and is associated with higher mortality. A variety of diagnostic imaging modalities have the potential to identify patients at high risk for development of TAVR-AKI; however, there are no existing consensus recommendations regarding their use as of this time. The implications of these findings highlight the importance of identifying high-risk patients for which preventive measures may play a crucial role, and should be maximized.

KEY MESSAGE

This study reviews the current understanding of TAVR-associated AKI including its pathophysiology, risk factors, diagnostic modalities, and preventative management for patients.

Early acute kidney injury after transcatheter aortic valve implantation: predictive value of currently available risk scores

BACKGROUND

Acute kidney injury (AKI) after transcatheter aortic valve implantation (TAVI) is a frequent complication associated with adverse outcomes and mortality. Various scores have been developed to predict this complication in the coronary setting. However, none have ever been tested in a large TAVI population. This study aimed to evaluate the power of four different scores in predicting AKI after TAVI.

METHODS

Overall, 1535 consecutive TAVI patients from the observational multicentric "Magna Graecia" TAVI registry were included in the analysis. Of the study population, 235 (15.31%) developed AKI early. The Mehran, William Beaumont Hospital, CR₄EATME₃AD₃, and ACEF scores were calculated retrospectively.

RESULTS

The patients who developed TAVI-related AKI had significantly higher absolute values of all risk scores than those who did not. The receiver-operating characteristic analysis also showed a significant correlation between these four scores and AKI, but without a significant difference among all of them (p value = 0.176). Nevertheless, based on their area under the curve values (≤0.604 for all), none had adequate diagnostic accuracy in predicting TAVI-related AKI. Importantly, multivariate analysis identified myocardial revascularization close to the TAVI procedure and implantation of self-expanding prostheses, as well as atrial fibrillation, low-osmolar contrast media administration, corrected contrast medium volume, and any transfusion (p value < 0.05 for all) as independent risk factors for AKI.

CONCLUSIONS

Although high values of current AKI risk scores are significantly associated with the development of this complication, these are not sufficiently accurate. Further studies are needed so that a TAVI-dedicated AKI risk score may be created.

Optimal timing for percutaneous coronary intervention in patients undergoing transcatheter aortic valve implantation

BACKGROUND

The best timing to perform percutaneous coronary interventions (PCI) in patients undergoing TAVI is unknown. Most PCI are performed before TAVI, because of concerns about potential ischemic complications during valve implantation. In this study we aimed to compare short-and long-term outcomes of patients undergoing PCI before or after TAVI.

METHODS

Patients undergoing TAVI and PCI from 2010 to 2021 were analyzed. PCI was defined as high-risk when involving unprotected left main, proximal left anterior descending, proximal dominant right coronary artery or 3-vessel disease. The primary endpoint was the cumulative incidence of any TAVI procedural complication and in-hospital adverse events (VARC-3 criteria).

RESULTS

Out of 1162 patients, 144 underwent PCI, 68% after TAVI, 78.4% of which were at high-risk. The primary endpoint occurred in 28.4% of patients in PCI pre-TAVI group vs 21.4% in PCI post-TAVI group (p = 0.403) and in 34.4% vs 17.3% of patients respectively among high-risk patients (p = 0.075). A higher rate of stroke was observed in the PCI pre-TAVI group regardless of the PCI complexity (6.5% vs 0.0%, p = 0.031; 9.3% vs 0.0% p = 0.025 in the high-risk group). At 24 months, MACCE-free survival was lower in patients who underwent PCI before TAVI (84.4% vs 97.9%, adjusted HR 10.16, 95% CI 1.19-86.57, p = 0.019; and 84.4% vs 97.3%, adjusted HR 7.34 95% CI 0.78-62.28 p = 0.082 in the high-risk group).

CONCLUSIONS

PCI performed after TAVI does not expose patients to higher risks of peri-procedural hazards and provides a trend towards favourable clinical outcome at mid-to-long term.

Volume of contrast to creatinine clearance ratio predicts early mortality and AKI after TAVI

The volume of contrast to creatinine clearance ratio (CV/CrCl) is a useful indicator of the risk of acute kidney injury (AKI) in patients undergoing percutaneous interventional procedures. Association between CV/CrCl and adverse outcome after transcatheter aortic valve implantation (TAVI) was suggested but it is not well established. A large retrospective multicenter cohort of 1381 patients treated with TAVI was analyzed to assess the association between CV/CrCl and the risk of AKI and mortality at 90 days and 1 year after TAVI. Patients receiving renal replacement therapy at the time of TAVI were excluded. CV/CrCl ≥ 2.2 was associated with the risk of AKI and 90 days mortality after TAVI after adjustment for age, sex, diabetes, baseline left ventricular function, baseline chronic kidney disease (CKD), previous myocardial infarction and peripheral vascular disease (hazard ratio [HR]: 1.16, 95% confidence interval [CI]: 1.09–1.22, p < 0.0001). Importantly, CV/CrCl was associated with the adverse outcome independently from the presence of baseline CKD (p for interaction = 0.22). CV/CrCl was independently associated with the individual components of the composite primary outcome including AKI (odds ratio: 1.18, 95% CI: 1.08–1.28, p < 0.0001) and 90 days mortality (HR: 1.90, 95% CI: 1.01–3.60, p = 0.047) after TAVI. AKI (HR: 1.94, 95% CI: 1.21–3.11, p = 0.006) but not CV/CrCl was associated with the risk of 1‐year mortality after TAVI. CV/CrCl is associated with excess renal damage and early mortality after TAVI. Procedural strategies to minimize the CV/CrCl during TAVI may improve early clinical outcomes in patients undergoing TAVI.

Early clinical outcomes after transaxillary versus transfemoral TAVI. Data from the Spanish TAVI registry

INTRODUCTION AND OBJECTIVES

Transaxillary access (TXA) has become the most widely used alternative to transfemoral access (TFA) in patients undergoing transcatheter aortic valve implantation (TAVI). The aim of this study was to compare total in-hospital and 30-day mortality in patients included in the Spanish TAVI registry who were treated by TXA or TFA access.

METHODS

We analyzed data from patients treated with TXA or TFA and who were included in the TAVI Spanish registry. In-hospital and 30-day events were defined according to the recommendations of the Valve Academic Research Consortium. The impact of the access route was evaluated by propensity score matching according to clinical and echocardiogram characteristics.

RESULTS

A total of 6603 patients were included; 191 (2.9%) were treated via TXA and 6412 via TFA access. After adjustment (n=113 TXA group and n=3035 TFA group) device success was similar between the 2 groups (94%, TXA vs 95%, TFA; P=.95). However, compared with the TFA group, the TXA group showed a higher rate of acute myocardial infarction (OR, 5.3; 95%CI, 2.0-13.8); P=.001), renal complications (OR, 2.3; 95%CI, 1.3-4.1; P=.003), and pacemaker implantation (OR, 1.6; 95%CI, 1.01-2.6; P=.03). The TXA group also had higher in-hospital and 30-day mortality rates (OR, 2.2; 95%CI, 1.04-4.6; P=.039 and OR, 2.3; 95%CI, 1.2-4.5; P=.01, respectively).

CONCLUSIONS

Compared with ATF, TXA is associated with higher total mortality, both in-hospital and at 30 days. Given these results, we believe that TXA should be considered only in those patients who are not suitable candidates for TFA.

Acute Kidney Injury After Repeated Exposure to Contrast Material for Coronary Angiography

Objective

To assess the incidence of contrast-associated acute kidney injury (CAAKI) after repeated exposure to contrast material for computed tomography (CT) and conventional coronary angiography within short intervals.

Methods

We studied 651 patients enrolled in the CorE-64 (November 5, 2005–January 30, 2007) and CORE320 (October 21, 2009–August 17, 2011) multicenter studies. Participants with suspected obstructive coronary heart disease were referred for diagnostic cardiac catheterization and underwent coronary CT angiography for research before invasive angiography. Nonionic, low-osmolality iodinated contrast material was used for all imaging.

Results

The median age of the patients was 62 years, and 190 (29%) were women. Major risk factors for acute kidney injury were present in 277 of 651 (43%) patients. The median interval between CT imaging and invasive angiography was 3.1 days (interquartile range, 0.9-8.0 days). The median volume of contrast material was 100 mL for each test. In 16 (2.5%) of 651 patients, CAAKI developed. Of these cases, 1 occurred after the CT scan, whereas 6 were documented after invasive angiography (compared with post-CT creatinine concentration assessment). In 9 patients, CAAKI was found in comparing creatinine concentration after completion of both tests with baseline values (but not compared with post-CT imaging).

Conclusion

Acute kidney injury after repeated exposure to iodinated contrast media within a few days is uncommon even in a population of patients with highly prevalent risk factors. Withholding of clinically indicated contrast-enhanced imaging may therefore not be justified in this setting.

Impact of contrast medium osmolality on the risk of acute kidney injury after transcatheter aortic valve implantation: insights from the Magna Graecia TAVI registry

BACKGROUND

Acute kidney injury (AKI) after transcatheter aortic valve implantation (TAVI) is frequent and associated with adverse outcomes and mortality; to date, in such setting of patients there is no consistent evidence that either low-osmolar contrast media (LOCM) or iso-osmolar contrast medium (IOCM) are superior to the other in terms of renal safety.

METHODS

697 consecutive patients not in hemodialysis treatment who underwent TAVI (327 males, mean age 81.01 ± 5.75 years, mean european system for cardiac operative risk evaluation II 6.17 ± 0.23%) were enrolled. According to osmolality of the different iodinated CM, the population was divided in 2 groups: IOCM (n = 370) and LOCM group (n = 327). Preoperatively, 40.54% of patients in IOCM vs 39.14% in LOCM group (p = 0.765) suffered from chronic kidney disease (CKD).

RESULTS

The incidence of AKI was significantly lower with IOCM (9.73%) than with LOCM (15.90%; p = 0.02), and such significant difference (p < 0.001) in postprocedural change of renal function parameters persisted at discharge too. The incidence of AKI was also significantly lower with IOCM in younger patients, without diabetes, anemia, coronary artery disease history, CKD, chronic or persistent atrial fibrillation, left ventricular ejection fraction ≤35%, and in patients with low operative mortality risk scores, receiving lower amounts of dye (p < 0.05 for all). Importantly, multivariate analysis identified LOCM administration as an independent risk factor for both AKI (p = 0.006) and 1-year mortality (p = 0.001).

CONCLUSIONS

The use of IOCM have a favorable impact on renal function with respect to LOCM, but it should be considered especially for TAVI patients at lower AKI risk.

Evaluating the Association between Contrast Medium Dosage and Acute Kidney Injury in Transcatheter Aortic Valve Replacement Using Different Predictive Models

Recent studies have suggested that contrast medium (CM) volume is associated with acute kidney injury (AKI) after transcatheter aortic valve replacement (TAVR). However, in a high-risk elderly TAVR population, the prognostic value and ideal threshold of CM dosage for AKI is unclear. Data of 532 successive TAVR patients (age 81.1 ± 6.8 years, EuroSCORE II 4.8% ± 6.0%) were therefore retrospectively analyzed. Based on a recently published formula, the renal function (preprocedural serum creatinine: SCr) corrected ratio of CM and body weight (CM*SCr/BW) was calculated to determine the risk of postprocedural contrast-associated AKI. AKI occurred in 94 patients (18.3%) and significantly increased 1-year all-cause mortality (23.4% vs. 13.1%; p = 0.001). A significant correlation between AKI and 30-day as well as 1-year all-cause mortality was observed (p = 0.001; p = 0.007). However, no association between CM dosage or the CM*SCr/BW ratio with the occurrence of AKI was seen (p = 0.968; p = 0.442). In our all-comers, all-access cohort, we found no relationship between CM dosage, or the established risk ratio model and the occurrence of postprocedural AKI. Further research needs to be directed towards different pathophysiological causes and preventive measures as AKI impairs short- and long-term survival.

Abdominal adiposity assessed using CT angiography associates with acute kidney injury after trans-catheter aortic valve replacement

AIM

To determine if there is an association between area-based visceral abdominal adipose tissue (VAT), subcutaneous abdominal adipose tissue (SAT), and abdominal circumference measured on computed tomography (CT) angiography before trans-catheter aortic valve replacement (TAVR) and post-TAVR acute kidney injury (AKI).

MATERIALS AND METHODS

In this retrospective cohort study of 106 TAVR patients, SAT and VAT areas and abdominal circumference was measured on a single CT section at L4 vertebral level. Univariate comparisons between patients who did and did not develop AKI were undertaken for radiological measurements. Multivariable logistic regression was used to assess association between CT measurements and the development of post-TAVR AKI.

RESULTS

Post-TAVR AKI occurred in 20 of 106 patients (19%). In univariate comparisons, body mass index (BMI) did not differ significantly between patients who did and did not develop AKI (p=0.14); however, VAT+SAT (443.2±163.7 versus 351±168.7 cm²; p=0.03), VAT (213.9±110.6 versus 153.9±96.1 cm²; p=0.03), and outer abdominal circumference (100.2±14.4 cm versus 91.8±13.3 cm; p=0.02) were significantly higher in the patients who did not develop post-TAVR AKI. These three measures on pre-TAVR CT angiogram remained significantly associated with reduced post-TAVR AKI with a lower incidence of post-TAVR AKI after multivariable adjustment for pre-TAVR estimated glomerular filtration rate and patient height (p<0.05).

CONCLUSION

This study found that increased abdominal obesity as assessed by measures on pre-TAVR CT angiogram is associated with a significantly lower incidence of AKI.

New Insights Into Mechanisms of Acute Kidney Injury in Heart Disease

Acute kidney injury is a frequent occurrence in patients with heart disease, and is associated with higher risk of adverse outcomes, including mortality. In the setting of decompensated heart failure, acute kidney injury can occur from hemodynamic and neurohormonal activation, venous congestion, and nephrotoxic medications. Certain medications, such as loop diuretics, renin angiotensin system blockers, and mineralocorticoid antagonists can seemingly cause acute kidney injury. However, this increase in creatinine level is not always associated with adverse outcomes and should be carefully differentiated so as to allow deliberate continuation of these cardio- and nephroprotective agents. In other settings such as cardiac surgery, acute kidney injury can occur from factors related to the cardiopulmonary bypass, renal hypoperfusion, or other perioperative factors. Last, patients with heart disease commonly undergo imaging procedures that require contrast administration. Contrast can indeed cause acute kidney injury, but these interventional procedures also can result in kidney injury from atheroembolic phenomena. This is well documented by the recent data reporting a higher risk of acute kidney injury from femoral compared with radial access. The advent of biomarkers of kidney injury present an opportunity for early detection, accurate differential diagnosis, as well as potentially designing innovative biomarker-enriched adaptive clinical trials.

Clinical effects of acute kidney injury after transcatheter aortic valve implantation: a systematic review and meta-analysis

Several observational studies have shown that postoperative acute kidney injury (AKI) may significantly worsen the prognosis of a transcatheter aortic valve implantation (TAVI). The purpose of this systematic review and meta-analysis is to evaluate the recent evidence on the impact of AKI on clinical outcomes following TAVI. A comprehensive search in PubMed, Embase and the Cochrane Library was performed for relevant studies by two independent investigators. We pooled the odds ratio (OR) from individual studies, and performed heterogeneity, quality assessment and publication bias analysis. Forty-three eligible studies comprising 544,112 patients were included. Postoperative AKI not only significantly increased the risk for short-term and long-term all-cause mortality (OR 6.25, 95% CI 5.72-6.83, P < 0.00001; OR 3.49, 95% CI 2.78-4.40, P < 0.00001, respectively), but also increased the risk for early myocardial infarction (OR 3.98, 95% CI 1.90-8.31, P = 0.0002), major and life-threatening bleeding (OR 1.51, 95% CI 1.12-2.03, P = 0.007; OR 2.35, 95% CI 1.80-3.06, P < 0.00001, respectively), major vascular complications (OR 1.69, 95% CI 1.30-2.18, P < 0.0001), need for blood transfusion (OR 2.15, 95% CI 1.89-2.46, P < 0.00001) renal replacement therapy (OR 22.36, 95% CI 11.88-42.12, P = 0.0002) and cerebrovascular accidents (OR 1.92, 95% CI 1.23-2.98, P = 0.004). Acute kidney injury following TAVI is associated with increased postoperative mortality and morbidity. Future efforts are required to determine whether early prevention of post-procedural AKI after TAVI impacts upon clinical outcomes.

Transcatheter aortic valve thrombosis: the relation between hypo-attenuated leaflet thickening, abnormal valve haemodynamics, and stroke

Aims

The presence of hypo-attenuated leaflet thickening (HALT) and/or reduced leaflet motion on multi-detector row computed tomography (MDCT) has been proposed as a possible marker for early transcatheter aortic valve thrombosis. However, its association with abnormal valve haemodynamics on echocardiography (another potential marker of thrombosis) and clinical outcomes (stroke) remains unclear. The present study evaluated the prevalence of HALT on MDCT and abnormal valve haemodynamics on echocardiography. In addition, the occurrence of ischemic stroke and/or transient ischemic attack (TIA) was assessed.

Methods and results

A total of 434 patients (mean age 80 ± 7 years, 51% male) who underwent transcatheter aortic valve replacement (TAVR) were evaluated. Transcatheter valve haemodynamics were assessed on echocardiography at discharge, 6 months, and thereafter yearly (up to 3 years post-TAVR). The presence of HALT and/or reduced leaflet motion was assessed on MDCT performed 35 days [interquartile range 19-210] after TAVR in 128 of these 434 patients. Possible TAVR valve thrombosis was defined by mean transvalvular gradient ≥20 mmHg and aortic valve area (AVA) ≤1.1cm2 on echocardiography or by the presence of HALT or reduced leaflet motion on MDCT. The occurrence of ischemic stroke/TIA at follow-up was recorded. HALT and/or reduced leaflet motion was present in 12.5% of 128 patients undergoing MDCT, and was associated with a slightly higher mean transvalvular gradient (12.4 ± 8.0 mmHg vs. 9.4 ± 4.3 mmHg; P = 0.026) and smaller AVA (1.49 ± 0.39 cm2 vs. 1.78 ± 0.45 cm2, P = 0.017). Only one patient with HALT on MDCT revealed abnormal valve haemodynamics on echocardiography. At 3-year follow-up, abnormal valve haemodynamics on echocardiography were observed in 3% of patients. HALT on MDCT and abnormal valve haemodynamics on echocardiography were not associated with increased risk of ischemic stroke/TIA.

Conclusion

On MDCT, 12.5% of patients showed HALT or reduced leaflet motion, whereas only one of these patients had abnormal valve haemodynamics on echocardiography. Neither HALT nor increased transvalvular gradient were associated with stroke/TIA.

Frequency and Prognostic Significance of Acute Kidney Recovery in Patients Who Underwent Transcatheter Aortic Valve Implantation

Acute kidney injury (AKI) after transcatheter aortic valve implantation (TAVI) is associated with increased mortality. As significant hemodynamic improvement may occur with relief of aortic stenosis, we hypothesized that TAVI patients may demonstrate the opposite phenomena: acute kidney recovery (AKR). We studied the incidence and predictors of AKR in post-TAVI patients. A total of 366 consecutive patients underwent TAVI (January 2012 to January 2017) at a single center. We defined AKR as a 25% improvement in glomerular filtration rate (GFR) at 48 hours after TAVI. AKI-creatinine (Cr) was defined as an increase in Cr of ≥0.3 mg/dl at 48 hours. Patients were categorized in 3 groups: AKR (≥25% increase in GFR), unchanged GFR, and AKI-GFR (inverse definition of AKR, ≥25% decrease in GFR). Multivariable logistic regression defined independent predictors of AKR. AKR occurred in 1/3 of patients. AKI-Cr occurred in 13% of patients, whereas AKI-GFR occurred similarly in 15%. AKR and AKI occurred most frequently in patients with chronic kidney disease (CKD: GFR ≤ 60 ml/min/1.73 m²). Independent predictors of AKR-GFR by multivariable analysis were male gender, lack of chronic β-blocker utilization, and presence of CKD. Notably, left ventricular dysfunction and contrast volume were not predictive of AKR. Transfusion occurred less frequently among patients with AKR compared with patients with AKI-GFR (11% vs 26%, p = 0.03). Death occurred in 0% of AKR patients versus 9.3% of AKI-GFR patients (p <0.01). In conclusion, this is the first report of AKR after TAVI. Patients with CKD, male gender, and lack of pre-TAVI beta blockade were more likely to demonstrate AKR.

Cholesterol Crystal Embolism and Chronic Kidney Disease

Renal disease caused by cholesterol crystal embolism (CCE) occurs when cholesterol crystals become lodged in small renal arteries after small pieces of atheromatous plaques break off from the aorta or renal arteries and shower the downstream vascular bed. CCE is a multisystemic disease but kidneys are particularly vulnerable to atheroembolic disease, which can cause an acute, subacute, or chronic decline in renal function. This life-threatening disease may be underdiagnosed and overlooked as a cause of chronic kidney disease (CKD) among patients with advanced atherosclerosis. CCE can result from vascular surgery, angiography, or administration of anticoagulants. Atheroembolic renal disease has various clinical features that resemble those found in other kidney disorders and systemic diseases. It is commonly misdiagnosed in clinic, but confirmed by characteristic renal biopsy findings. Therapeutic options are limited, and prognosis is considered to be poor. Expanding knowledge of atheroembolic renal disease due to CCE opens perspectives for recognition, diagnosis, and treatment of this cause of progressive renal insufficiency.

Independent Risk Factors Contributing to Acute Kidney Injury According to Updated Valve Academic Research Consortium-2 Criteria After Transcatheter Aortic Valve Implantation: A Meta-analysis and Meta-regression of 13 Studies

OBJECTIVES

This study aimed to examine the risk factors for transcatheter aortic valve implantation (TAVI)-associated acute kidney injury (AKI) according to the AKI definition from the Valve Academic Research Consortium-2 (VARC-2).

SETTING

A meta-analysis.

PARTICIPANTS

A total of 661 patients with post-TAVI AKI according to the VARC-2 definition and 2,012 controls were included in the meta-analysis.

INTERVENTIONS

Patients undergoing TAVI were included in this meta-analysis.

MEASUREMENTS AND MAIN RESULTS

Multiple electronic databases were searched using predefined criteria. The diagnosis of AKI was based on the VARC-2 classification. The authors found that preoperative New York Heart Association class IV (odds ratio [OR], 7.77; 95% confidence interval [CI], 3.81-15.85), previous chronic renal disease (CKD) (OR, 2.81; 95% CI, 1.96-4.03), and requirement for transfusion (OR, 2.03; 95% CI, 1.59-2.59) were associated significantly with an increased risk for post-TAVI AKI. Furthermore, previous peripheral vascular disease (PVD), hypertension, atrial fibrillation, congestive heart failure, diabetes mellitus, and stroke were also risk factors for TAVI-associated AKI. Additionally, transfemoral access significantly correlated with a reduced risk for post-TAVI AKI (OR, 0.43; 95% CI, 0.33-0.57). The potential confounders, including Society of Thoracic Surgeons Score, the logistic European System for Cardiac Operative Risk Evaluation, aortic valve area, mean pressure gradient, left ventricular ejection fraction, age, body mass index, contrast volume, and valve type, had no impact on the association between the risk factors and post-TAVI AKI. Subgroup analysis of the eligible studies presenting multivariate logistic regression analysis on the independent risk factors for post-TAVI AKI revealed that previous CKD, previous PVD, and transapical access were independent risk factors for TAVI-associated AKI.

CONCLUSIONS

The current meta-analysis suggested that previous CKD, previous PVD, and transapical access may be independent risk factors for TAVI-associated AKI.

Association of blood transfusion with acute kidney injury after transcatheter aortic valve replacement: A meta-analysis

AIM

To assess red blood cell (RBC) transfusion effects on acute kidney injury (AKI) after transcatheter aortic valve replacement (TAVR).

METHODS

A literature search was performed using MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, and clinicaltrials.gov from the inception of the databases through December 2015. Studies that reported relative risk, odds ratio or hazard ratio comparing the risks of AKI following TAVR in patients who received periprocedural RBC transfusion were included. Pooled risk ratio (RR) and 95%CI were calculated using a random-effect, generic inverse variance method.

RESULTS

Sixteen cohort studies with 4690 patients were included in the analyses to assess the risk of AKI after TAVR in patients who received a periprocedural RBC transfusion. The pooled RR of AKI after TAVR in patients who received a periprocedural RBC transfusion was 1.95 (95%CI: 1.56-2.43) when compared with the patients who did not receive a RBC transfusion. The meta-analysis was then limited to only studies with adjusted analysis for confounders assessing the risk of AKI after TAVR; the pooled RR of AKI in patients who received periprocedural RBC transfusion was 1.85 (95%CI: 1.29-2.67).

CONCLUSION

Our meta-analysis demonstrates an association between periprocedural RBC transfusion and a higher risk of AKI after TAVR. Future studies are required to assess the risks of severe AKI after TAVR requiring renal replacement therapy and mortality in the patients who received periprocedural RBC transfusion.

The risk of acute kidney injury following transapical versus transfemoral transcatheter aortic valve replacement: a systematic review and meta-analysis

Background

The aim of this systematic review is to examine the literature for the risk of acute kidney injury (AKI) in patients who underwent transcatheter aortic valve replacement (TAVR) based on transapical (TA) versus transfemoral (TF) approaches.

Methods

A literature search was conducted utilizing Embase, Medline, Cochrane Database of Systematic Reviews and ClinicalTrials.gov from inception through December 2015. Studies that reported relative risk, odds ratio or hazard ratio comparing the AKI risk in patients who underwent TA-TAVR versus TF-TAVR were included. Pooled risk ratio (RR) and 95% confidence interval (CI) were calculated using a random effect, generic inverse variance method.

Results

Seventeen cohort studies with 5085 patients were enrolled in the analysis to assess the risk of AKI in patients undergoing TA-TAVR versus TF-TAVR. The pooled RR of AKI in patients who underwent TA-TAVR was 2.26 (95% CI 1.79–2.86) when compared with TF-TAVR. When meta-analysis was confined to the studies with adjusted analysis for confounders evaluating the risk of AKI following TAVR, the pooled RR of TA-TAVR was 2.89 (95% CI 2.12–3.94). The risk for moderate to severe AKI [RR 1.02 (95% CI 0.57–1.80)] in patients who underwent TA-TAVR compared with TF-TAVR was not significantly higher.

Conclusions

Our meta-analysis demonstrates an association between TA-TAVR and a higher risk of AKI. Future studies are required to assess the risks of moderate to severe AKI and mortality following TA-TAVR versus TF-TAVR.

MRI evaluation prior to Transcatheter Aortic Valve Implantation (TAVI): When to acquire and how to interpret

Transcatheter Aortic Valve Implantation (TAVI) is increasingly being used in patients with severe aortic stenosis who are not candidates for surgery. ECG-gated CT angiography (CTA) plays an important role in the preoperative planning for these devices. As the number of patients undergoing these procedures increases, a subset of patients is being recognized who have contraindications to iodinated contrast medium, either due to a prior severe allergic type reaction or poor renal function. Another subgroup of patients with low flow and low gradient aortic stenosis is being recognized that are usually assessed for severity of aortic stenosis by stress echocardiography. There are contraindications to stress echocardiography and some of these patients may not be able to undergo this test. Non-contrast MRI can be a useful emerging modality for evaluating these patients. In this article, we discuss the emerging indications of non-contrast MRI in preoperative assessment for TAVI and describe the commonly used MRI sequences. A comparison of the most important measurements obtained for TAVI assessment on CTA and MRI from same subjects is included. Teaching Points • MRI can be used for preoperative assessment of aortic annulus. • MRI is an alternate to CTA when iodinated contrast is contraindicated. • Measurements obtained by non-contrast MRI are similar to contrast enhanced CTA. • MRI can be used to assess severity of aortic stenosis.

Acute kidney injury after transcatheter aortic valve implantation

Even though experience and techniques have constantly improved over the last years, peri- and postprocedural complications in high risk TAVI-collectives remain a major issue affecting outcome and survival. Acute kidney injury (AKI) is a frequent complication after transcatheter aortic valve implantation (TAVI) and effects outcome and survival. However, the definition of AKI in published studies dealing with the phenomenon of AKI after TAVI varies widely and lacks standardization. This Review aims to present an overview over the current literature concerning AKI after TAVI with regard to the definition of AKI, the impact of AKI on mortality and potential risk factors for renal impairment after TAVI.