Effect of Transcatheter Aortic Valve Implantation on Renal Function in Patients With Chronic Kidney Disease

Valvular Heart Disease in Patients with Chronic Kidney Disease

Valvular heart disease (VHD) is highly prevalent in patients with chronic kidney disease (CKD) from the early stages to end-stage renal disease (ESRD). Aortic and mitral valves are the most frequently affected, leading to aortic valve and/or mitral annular calcification, which, in turn, causes either valve stenosis or regurgitation at an accelerated rate compared with the general population. Tricuspid regurgitation is also prevalent in CKD and ESRD, and haemodialysis patients are at an increasingly high risk of infective endocarditis. As for pathophysiology, several mechanisms causing VHD in CKD have been proposed, highlighting the complexity of the process. Echocardiography constitutes the gold standard for the assessment of VHD in CKD/ESRD patients, despite the progress of other imaging modalities. With regard to treatment, the existing 2017 European Society of Cardiology/European Association for Cardio-Thoracic Surgery guidelines on the management of VHD addressing patients with normal kidney function are also applied to patients with CKD/ESRD.

Assessment of Kidney Function After Transcatheter Aortic Valve Replacement

Background:

Transcatheter aortic valve replacement (TAVR), although associated with an increased risk for acute kidney injury (AKI), may also result in improvement in renal function.

Objective:

The aim of this study is to evaluate the magnitude of kidney function improvement (KFI) after TAVR and to assess its significance on long-term mortality.

Design:

This is a prospective single center study.

Setting:

The study was conducted in cardiology department, interventional unit, in a tertiary hospital.

Patients:

The cohort included 1321 patients who underwent TAVR.

Measurements:

Serum creatinine level was measured at baseline, before the procedure, and over the next 7 days or until discharge.

Methods:

Kidney function improvement was defined as the mirror image of AKI, a reduction in pre-procedural to post-procedural minimal creatinine of more than 0.3 mg/dL, or a ratio of post-procedural minimal creatinine to pre-procedural creatinine of less than 0.66, up to 7 days after the procedure. Patients were categorized and compared for clinical endpoints according to post-procedural renal function change into 3 groups: KFI, AKI, or preserved kidney function (PKF). The primary endpoint was long-term all-cause mortality.

Results:

The incidence of KFI was 5%. In 55 out of 66 patients patients, the improvement in kidney function was minor and of unclear clinical significance. Acute kidney injury occurred in 19.1%. Estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m² was a predictor of KFI after multivariable analysis (odds ratio = 0.93 to develop KFI; confidence interval [95% CI]: 0.91-0.95, P < .001). Patients in the KFI group had a higher Society of Thoracic Surgery (STS) score than other groups. Mortality rate did not differ between KFI group and PKF group (43.9% in KFI group and 33.8% in PKF group) but was significantly higher in the AKI group (60.7%, P < .001).

Limitations:

The following are the limitations: heterozygous definitions of KFI within different studies and a single center study. Although data were collected prospectively, analysis plan was defined after data collection.

Conclusions:

Improvement in kidney function following TAVR was not a common phenomenon in our cohort and did not reduce overall mortality rate.

Worsening renal function after transcatheter aortic valve replacement and surgical aortic valve replacement

Several prior reports have investigated worsening renal function around transcatheter aortic valve replacement (TAVR) procedures. However, in clinical practice, it seems more important to evaluate changes associated with TAVR-related procedures, including preoperative enhanced computed tomography (CT), as well as the TAVR procedure itself, as CT assessment is considered essential for safe TAVR. This study evaluated worsening renal function during the TAVR perioperative period, from the preoperative enhanced CT to 1 month after TAVR, and then compared the incidence with that in patients undergoing surgical aortic valve replacement (SAVR). This retrospective single-center study investigated 123 TAVR patients and 130 SAVR patients. We evaluated baseline renal function before enhanced CT in TAVR patients and before operation in SAVR patients, and again at 1 month post-operatively. We defined worsening renal function at 1 month according to three definitions: (1) an increase in serum creatinine ≥ 0.3 mg/dL or ≥ 1.5-fold from baseline or initiation of dialysis, (2) a decline in eGFR at 1 month ≥ 20% from baseline or initiation of dialysis, (3) a decline in eGFR at 1 month ≥ 30% from baseline or initiation of dialysis. TAVR patients were significantly older and had higher surgical risk scores than SAVR patients. In TAVR patients, serum creatinine levels were 1.00 ± 0.32 mg/dL at baseline and 1.01 ± 0.40 mg/dL at 1 month post-operatively (p = 0.58), while in SAVR patients, these levels were 0.99 ± 0.51 mg/dL and 0.98 ± 0.49 mg/dL, respectively (p = 0.59). In TAVR patients, 7 (5.7%), 14 (11.4%), and 3 (2.4%) patients experienced worsening renal function according to the three definitions, respectively, but there were no significant differences from those in SAVR patients, for any definition. Worsening renal function after TAVR was uncommon, and the incidence rate was comparable to that in SAVR patients, even though TAVR patients had worse baseline characteristics.