Ultrasonographic assessment of atherosclerotic renal artery stenosis in elderly patients with chronic kidney disease: An Italian cohort study

Ultrasonographic assessment of atherosclerotic renal artery stenosis in elderly patients with chronic kidney disease: An Italian cohort study

REVIEWED BY Heath Edwards, AFASA | ASA SIG: Vascular

REFERENCE | Authors: Battaglia Y, Fiorini F, Gisonni P, Imbriaco M, Lentini P, Zeiler M, Russo L, Prencipe M & Russo D

WHY THE STUDY WAS PERFORMED

Atherosclerotic stenosis of the renal artery is caused by the presence of plaque forming within the proximal renal artery or at the ostium. Over time, the stenosis can worsen, often leading to reduced blood flow to the renal cortex causing renal ischaemia. The consequence of renal ischaemia is the activation of the renin-angiotensin-aldosterone system resulting in alteration to haemodynamics, peripheral vasoconstriction, sodium/water retention, cortical hypoxia, local release of cytokine and irreversible parenchymal injury.

Atheroma causing a renal artery stenosis is also responsible for poor control of hypertension, more frequent hospitalisation, new onset of chronic kidney disease (CKD), faster progression of pre-existing CKD towards dialysis (end-stage renal failure) and ultimately it will increase cardiovascular risks and mortality.

The study was performed to investigate and understand the prevalence, characteristics, and clinical implications of atherosclerotic renal artery stenosis (ARAS) in elderly patients who also have chronic kidney disease (CKD).

The study aimed to contribute valuable insights into how ARAS affected elderly patients with CKD by using ultrasound as a noninvasive method for assessment, which was particularly relevant given our ageing population and the increasing prevalence of chronic kidney disease globally.

HOW THE STUDY WAS PERFORMED

The study, conducted at the University of Naples, was a retrospective, observational, longitudinal investigation involving consecutive in-patients meeting specific criteria. A summarised breakdown of the methods is provided below.

STUDY DESIGN AND PARTICIPANTS

• Design: Retrospective, observational, longitudinal

• Participants: In-patients aged ≥ 65 years with CKD stages 2–5 (not on dialysis) and the presence of atherosclerotic plaques in specified arteries

• Inclusion criteria: Age ≥ 65 years, CKD stages 2–5, presence of atherosclerotic plaques confirmed by various imaging procedures

• Exclusion criteria: History of renal artery stenosis, kidney transplant, dialysis treatment.

DATA COLLECTION

• Pre-ultrasound measurement: Included clinical examination, personal/family medical history, and routine biochemistry

• Outcome measures: Recorded fatal and non-fatal cardiovascular events, treatments for ARAS or other plaques, and initiation of dialysis post-ultrasound.

ULTRASOUND TECHNIQUE

• Assessment: Duplex ultrasound (B-mode and Doppler) using a 2–5 MHz transducer

• Preparation: Fasting 8–12 hours to minimise bowel gas interference

• Diagnostic criteria: Significant ARAS defined by peak systolic velocity ≥ 200 cm/s and renalto-aorta peak systolic velocity ≥ 3.5.

OTHER DATA COLLECTION

• Coronary artery calcification: Assessed by multi-slice coronary computed tomography, scored in Agatston Units

• Plaque assessment: Defined by intima-medial thickness > 1.0 mm in specified vessels

• Biochemical markers: Included LDL cholesterol, hypertension, renal function (GFR), dyslipidemia, intact parathyroid hormone, and high sensitivity C-reactive protein.

Highlights the significant associations between atherosclerotic renal artery stenosis and specific clinical and biochemical parameters.

WHAT THE STUDY FOUND

From January 2015 to December 2018, 607 consecutive in-patients were screened. Data was collected from 120 patients who met the inclusion criteria before and after the ultrasound examination.

The chronic kidney stages were distributed among the patients in the following: Stage II (21%), Stage III (36.1), Stage IV (26.1%) and Stage V (16.8%). The cause of CKD was mostly unknown (51%), diabetic nephropathy (15%), glomerulonephritis (12%) and other causes (22%).

Atherosclerotic renal artery stenosis was found in 53 of the 120 cases (44%) with the right renal artery predominantly affected (58%). A bilateral ARAS was noted in only a single case. The median stenosis severity percentage was noted at 70%.

The clinical and biochemical parameters showed significant differences in basal BMI, GFR, haemoglobin, pulse pressure, serum calcium concentration and total coronary calcium score between the patients with an atherosclerotic renal artery stenosis and the controls. No differences were noted in the blood pressure levels, markers of mineral metabolism, dyslipidaemia, inflammation and nutritional markers.

RELEVANCE TO CLINICAL PRACTICE

This study highlights the significant associations between ARAS and specific clinical and biochemical parameters, with plaque present within the abdominal aorta/peripheral vessels and the patient’s GFR emerging as independent predictors. Utilising these findings will help contribute to understanding risk factors in the elderly and their potential outcomes if diagnosed with chronic kidney disease and an ARAS.

As sonographers, careful and accurate assessment of the proximal renal arteries and the ostium with ultrasound to identify atherosclerosis renal artery stenosis is important to support our clinicians in managing these patients.