Aortic Stenosis and Aortic Valve Replacement among Patients with Chronic Kidney Disease: A Narrative Review

National Outcomes of Cardiac Surgery in Patients Receiving Kidney Replacement Therapy

BACKGROUND

Studies estimating risks after cardiac surgery for patients receiving kidney replacement therapy have been limited by the size and generalizability of those cohorts. This study used data linked between registries to estimate short-term postoperative outcomes for large patient cohorts receiving kidney replacement therapy at the time of surgery.

METHODS

This population-based observational cohort study included adult patients who had undergone cardiac surgery in Australia between 2010 and 2019. Patient data were linked with a kidney replacement therapy registry to identify cohorts accurately and extract relevant data. Multivariable logistic regression estimated the risk of operative (30-day) mortality and other postoperative outcomes for long-term dialysis and functioning kidney transplant cohorts compared with each other and the general cardiac surgical population.

RESULTS

Of 114,496 surgeries, 1241 were in patients receiving long-term dialysis and 298 for those with a kidney transplant. The mortality rate was highest for patients who had valve-with-coronary artery bypass grafting for patients undergoing dialysis (18.78 per 100 surgeries; 95% CI, 13.37-25.25) and transplant recipients (14.00 per 100 surgeries; 95% CI, 5.82-26.74). Dialysis-treated patients had higher adjusted odds of mortality (odds ratio [OR], 4.17; 95% CI, 3.31-5.25) and all other measured outcomes than did the general population. Kidney transplant recipients had similarly elevated odds of mortality (OR, 3.52; 95% CI, 2.16-5.72).

CONCLUSIONS

Despite the younger age of the dialysis and transplant cohorts at surgery, operative mortality rates were higher, and the mortality rates for valve-with-coronary artery bypass grafting were 3.7- to 5-fold higher than those in the general population. Patients undergoing dialysis were a high risk for cardiac surgery, and the prognosis for kidney transplant recipients was similarly poor.

Outcomes of Patients with Critical Limb Ischemia and Chronic Kidney Disease: A National Perspective

INTRODUCTION

Studies exploring the relationship between peripheral arterial disease (PAD), critical limb ischemia (CLI), and chronic kidney disease (CKD) and its effect on in-hospital outcomes are limited. We aimed to analyze the outcomes of patients with CKD and PAD who are admitted for CLI.

METHODS

We utilized the National Inpatient Sample (NIS) to capture hospitalizations for CLI from 2012 to 2020 and then identified cases with concomitant CKD. The primary outcome was mortality, and secondary outcomes were cerebrovascular accident, major bleeding, vasopressor requirement, percutaneous coronary intervention, cardiac arrest, acute respiratory failure, transfusion, length of stay, and total hospital charges. Multivariable logistic regression was performed to adjust for covariates.

RESULTS

A total of 441,245 patients with CLI were identified, of which 122,370 (27.7%) reported concomitant CKD. Patients with CKD had higher in-patient mortality (odds ratio [OR] 1.68, 95% confidence interval [CI], 1.17-1.68, p < 0.001), vascular complications (OR 1.31, 95% CI, 1.17-1.48, p < 0.001), acute kidney injury requiring hemodialysis (OR 3.17, 95% CI, 2.64-3.80, p < 0.001), and major bleeding (OR 1.12, 95% CI, 1.05-1.19, p < 0.001). Patients with CKD underwent minimally invasive endovascular therapy (31.08% vs. 36.73%, p < 0.0001) and invasive procedures (14.73% vs. 23.55%, p < 0.0001) less often. PAD-CLI with CKD was associated with major (20.54% vs. 16.17%, OR 1.04; p < 0.0001) and minor (26.87% vs. 19.53%, OR 1.2, p < 0.0001) amputations more often.

CONCLUSION

Patients admitted for PAD-CLI with concomitant CKD have significantly higher in-hospital mortality as compared to patients without CKD. Moreover, patients with CKD and PAD-CLI are less likely to receive revascularization and more likely to undergo amputation.

Pioglitazone treatment mitigates cardiovascular bioprosthetic degeneration in a chronic kidney disease model

Aims

Chronic kidney disease (CKD) is a risk factor for the development of cardiovascular diseases, e.g., atherosclerosis and calcific aortic valve disease, leading inevitably to valve replacement surgery. CKD patients with bioprosthetic cardiovascular grafts, in turn, have a higher risk of premature graft degeneration. Peroxisome proliferator-activated receptor gamma (PPARγ) activation by pioglitazone has cardio-renal protective properties, and research using a heterotopic valve implantation model has shown anti-degenerative effects of PPARγ activation on bioprosthetic valved grafts (BVG) in rats. The present work aims to analyze a potential protective effect of pioglitazone treatment on BVG in an adenine-induced rat model of CKD.

Methods and Results

BVG of Sprague Dawley rats were heterotopically implanted in Wistar rats in an infrarenal position for 4 and 8 weeks. Animals were distributed into three groups for each time point: 1) control group receiving standard chow, 2) CKD group receiving 0.25% adenine and 3) CKD + pioglitazone group (300 mg per kg of 0.25% adenine chow). BVG function was analyzed by echocardiography. Plasma analytes were determined and explanted grafts were analyzed by semi-quantitative real-time PCR, Western blot analysis, histology and immunohistology.PPARγ activation significantly reduced CKD-induced calcification of aortic and valvular segments of BVG by 44% and 53%, respectively. Pioglitazone treatment significantly also reduced CKD-induced intima hyperplasia by 60%. Plasma analysis revealed significantly attenuated potassium and phosphate levels after pioglitazone treatment. Moreover, PPARγ activation led to significantly decreased interleukin-6 gene expression (by 57%) in BVG compared to CKD animals. Pioglitazone treatment leads to functional improvement of BVG.

Conclusion

This study broadens the understanding of the potential value of PPARγ activation in cardio-renal diseases and delineates pioglitazone treatment as a valuable option to prevent bioprosthetic graft failure in CKD. Further mechanistic studies, e.g., using small molecules activating PPARγ signaling pathways, are necessary for the evaluation of involved mechanisms. Additionally, the translation into pre-clinical studies using large animals is intended as the next research project.

Cardiac Devices and Kidney Disease

A growing variety of cardiac devices are available to monitor or support cardiovascular function. The entwined nature of cardiovascular disease and kidney disease makes the relationship of these devices with kidney disease a multifaceted question relating to the use of these devices in individuals with kidney disease and to the effects of the devices and device placement on kidney health. Cardiac devices can be categorized broadly into cardiac implantable electronic devices, structural devices, and circulatory assist devices. Cardiac implantable electronic devices include devices for monitoring and managing cardiac electrical activity and devices for monitoring hemodynamics. Structural devices modify cardiac structure and include valve prostheses, valve repair clips, devices for treating atrial septal abnormalities, left atrial appendage closure devices, and interatrial shunt devices. Circulatory assist devices support the failing heart or support cardiac function during high-risk cardiac procedures. Evidence for the use of these devices in individuals with kidney disease, effects of the devices on kidney health and function, specific considerations with devices in kidney disease, and important knowledge gaps are surveyed in this article. With the growing prevalence of combined cardiorenal disease and the increasing variety of cardiac devices, kidney disease considerations are an important aspect of device therapy.

In-hospital outcomes of transcatheter aortic valve replacement in patients with chronic and end-stage renal disease: a nationwide database study

BACKGROUND

Chronic kidney disease (CKD) and end-stage renal disease (ESRD) have been associated with worse outcomes after transcatheter aortic valve replacement (TAVR). With TAVR indications extending to a wider range of patient populations, it is important to understand the current implications of chronic renal insufficiency on clinical outcomes. We aim to determine the impact of CKD and ESRD on in-hospital outcomes after TAVR.

METHODS

We queried the National Inpatient Sample for TAVR performed between 2016 and 2020 using International Classification of Diseases-10th Revision codes. We compared in-hospital mortality and clinical outcomes between three groups: normal renal function, CKD and ESRD. The association between CKD/ESRD and outcomes was tested with multivariable logistic regression analyses, using normal renal function as baseline.

RESULTS

In the five-year study period, 279,195 patients underwent TAVR (mean age 78.9 ± 8.5 years, 44.4% female). Of all patients, 67.1% had normal renal function, 29.2% had CKD, and 3.7% had ESRD. There were significant differences in age, sex, and prevalence of comorbidities across groups. In-hospital mortality was 1.3%. Compared to patients with normal renal function, patients with renal insufficiency had higher in-hospital mortality, with the highest risk found in patients with ESRD (adjusted odds ratio: 1.4 [95% confidence interval: 1.2-1.7] for CKD; adjusted odds ratio: 2.4 [95% confidence interval: 1.8-3.3] for ESRD). Patients with CKD or ESRD had a higher risk of cardiogenic shock, need for mechanical circulatory support, and vascular access complications, compared to those with normal renal function. In addition, patients with ESRD had a higher risk of cardiac arrest and periprocedural acute myocardial infarction. The incidence of conversion to open heart surgery was 0.3% and did not differ between groups. Post-procedural infectious and respiratory complications were more common among patients with CKD or ESRD.

CONCLUSION

Patients with CKD and ESRD are at higher risk of in-hospital mortality, cardiovascular, and non-cardiovascular complications after TAVR. The risk of complications is highest in patients with ESRD and does not result in more frequent conversion to open heart surgery. These results emphasize the importance of individualized patient selection for TAVR and procedural planning among patients with chronic renal insufficiency.