Renal Artery Stenosis: Optimal Therapy and Indications for Revascularization

Evaluation of the therapeutic efficacy of renal artery stenting in patients with atherosclerotic renal artery stenosis

PURPOSE

It is currently controversial whether renal artery stenting is beneficial for the clinical outcomes of atherosclerotic renal artery stenosis (ARAS) patients. The study aims to evaluate whether blood pressure (BP) and renal function improve in ARAS patients after stenting.

METHODS

A retrospective study was conducted on 78 ARAS patients who underwent renal artery stenting at the First Affiliated Hospital of Chongqing Medical University from January 2013 to June 2024. BP, the number of oral antihypertensive medications, renal function, and adverse events were analyzed before and after stenting.

RESULTS

A total of 90 stents were implanted. The median follow-up time was 1.59 years. From 24 hours post-operation, significant decline in BP were observed. During follow-up, systolic BP decreased by 24.27 mmHg (95% CI: 16.54-32.00; P < 0.0001) and diastolic BP by 12.27 mmHg (95% CI: 7.25-17.29; P < 0.0001), but the reduction in the number of oral antihypertensive medications was not significant (P > 0.05). Serum creatinine also showed a significant decrease of 8.50 μmol/L at follow-up (P < 0.05). Among the four subgroups, 30 patients with mild renal impaired [eGFR ≥ 60 mL/(min·1.73 m2) and <90 mL/(min·1.73 m2)] showed an increase of 10.68 mL/(min·1.73 m2) in eGFR during follow-up (P < 0.01), while the eGFR of the remaining 48 patients with other renal function stages showed no significant change before and after stenting. Moreover, 24 patients experienced cardiovascular or/and renal adverse events.

CONCLUSIONS

Renal artery stenting might significantly reduce BP and improve renal function in ARAS patients, particularly those with mild renal impairment, which still requires prospective multicenter studies to confirm.

Therapy for Renal Artery Stenosis: A Call for Change

CLINICAL IMPACT

We present a brief case description of a patient who benefitted from stenting in ARAS and provide a comprehensive review of ARAS; its prevalence, pathophysiology, clinical manifestations, diagnosis and treatment. We review the evidence for and against stenting in ARAS as well as consensus guidelines for stenting. Our review is valuable as we argue that stenting in ARAS is underutilized and the randomized control data for stenting in those patients who may benefit most is lacking. Our review will provide an important perspective for clinicians faced with decisions of how to treat ARAS.

Secondary hypertension as a cause of treatment resistance

In secondary hypertension, elevated blood pressure is caused by a known and/or potentially treatable underlying disease.Although the prevalence of secondary hypertension depends on the patient population and the thoroughness of applied diagnostic approaches, arterial hypertension is classified in 90 to 95% as primary in nature. In young patients, individuals without a family history of hypertension, late onset of hypertension or worsening of a previous well-controlled hypertension as well as in patients who have a difficult to treat hypertension, the prevalence of secondary hypertension is significantly higher.Because the identification and the specific therapy of secondary hypertension may result in normalisation or improvement of elevated blood pressure in many cases, a targeted diagnostics is of great importance.

The impact of renal artery stenting on therapeutic aims

Renal artery stenosis manifests as poorly-controlled hypertension, impaired renal function or pulmonary oedema, therefore the success of treatment is dependent on indication. This study aims to determine the outcomes of patients undergoing renal artery stenting (RASt) based on therapeutic aim compared to criteria used in the largest randomised trial. Retrospective case-note review of patients undergoing RASt between 2008-2021 (n = 74). The cohort was stratified by indication for intervention (renal dysfunction, hypertension, pulmonary oedema) and criteria employed in the CORAL trial, with outcomes and adverse consequences reported. Intervention for hypertension achieved significant reduction in systolic blood pressure and antihypertensive agents at 1 year (median 43 mmHg, 1 drug), without detrimental impact on renal function. Intervention for renal dysfunction reduced serum creatinine by a median 124 μmol/L, sustained after 6 months. Intervention for pulmonary oedema was universally successful with significant reduction in SBP and serum creatinine sustained at 1 year. Patients who would have been excluded from the CORAL trial achieved greater reduction in serum creatinine than patients meeting the inclusion criteria, with equivalent blood pressure reduction. There were 2 procedure-related mortalities and 5 procedural complications requiring further intervention. 5 patients had reduction in renal function following intervention and 7 failed to achieve the intended therapeutic benefit. Renal artery stenting is effective in treating the indication for which it has been performed. Previous trials may have underestimated the clinical benefits by analysis of a heterogenous population undergoing a procedure rather than considering the indication, and excluding patients who would maximally benefit.

Renal revascularization by a pedicled intestinal segment wrapping the kidney: a new method for kidney revascularization

BACKGROUND

Renal artery stenosis is caused by a heterogeneous group of diseases, including atherosclerosis and fibromuscular dysplasia, which can be treated medically, via endovascular techniques, or by open revascularization; however, satisfactory and effective results are not always obtained. We aimed to assess the possibility of renal revascularization by a pedicled intestinal segment wrapping the kidney.

METHODS

Five dogs were operated on at three steps. At the first step, laparotomy was performed, and the right kidney was released. Subsequently, an 8-10 cm segment of jejunum was separated longitudinally, and mucosectomy was done. This intestinal patch wrapped up the kidney. After eight weeks, the kidney and the intestinal patch were analyzed, and the renal artery was ligated. After four weeks, the kidney and the intestinal patch were sent for pathological evaluation.

RESULTS

At the 12th week of evaluation, no evidence of abscess formation or collection was seen. All kidneys had a normal color, consistency, and size. All renal cells were alive, and neither atrophy nor necrosis was seen. Glomerulus and tubules were intact, and no inflammatory change was visible. Furthermore, thick wall vasculature was inspected in a fibromuscular tissue, rising from the intestinal flap toward the kidney. One of the dogs expired due to peritonitis and sepsis in the fifth week.

CONCLUSION

In our study, indirect perfusion of the kidney by an intestinal patch was achieved successfully. This represents new hope in patients suffering from chronic renal failure who underwent former medical and surgical interventions with undesirable results.

Resistant Hypertension: Detection, Evaluation, and Management: A Scientific Statement From the American Heart Association

Resistant hypertension (RH) is defined as above-goal elevated blood pressure (BP) in a patient despite the concurrent use of 3 antihypertensive drug classes, commonly including a long-acting calcium channel blocker, a blocker of the renin-angiotensin system (angiotensin-converting enzyme inhibitor or angiotensin receptor blocker), and a diuretic. The antihypertensive drugs should be administered at maximum or maximally tolerated daily doses. RH also includes patients whose BP achieves target values on ≥4 antihypertensive medications. The diagnosis of RH requires assurance of antihypertensive medication adherence and exclusion of the "white-coat effect" (office BP above goal but out-of-office BP at or below target). The importance of RH is underscored by the associated risk of adverse outcomes compared with non-RH. This article is an updated American Heart Association scientific statement on the detection, evaluation, and management of RH. Once antihypertensive medication adherence is confirmed and out-of-office BP recordings exclude a white-coat effect, evaluation includes identification of contributing lifestyle issues, detection of drugs interfering with antihypertensive medication effectiveness, screening for secondary hypertension, and assessment of target organ damage. Management of RH includes maximization of lifestyle interventions, use of long-acting thiazide-like diuretics (chlorthalidone or indapamide), addition of a mineralocorticoid receptor antagonist (spironolactone or eplerenone), and, if BP remains elevated, stepwise addition of antihypertensive drugs with complementary mechanisms of action to lower BP. If BP remains uncontrolled, referral to a hypertension specialist is advised.

Descendo-bifemoral bypass grafting and renal artery revascularization to treat complex obliterative arteriopathy

OBJECTIVES

Our goal was to describe a new standardized approach in patients with extensive obliterative arteriopathy aimed at distal revascularization and surgical kidney recruitment via descendo-bifemoral bypass grafting and renal artery revascularization.

METHODS

Three patients with Leriche's syndrome and either a compromised single kidney or unilateral significant renal artery stenosis were treated with a standardized surgical approach, restoration of distal perfusion via descendo-bifemoral bypass with synchronous ( n  = 2) left-sided renal artery revascularization or metachronous ( n  = 1) right-sided renal artery revascularization.

RESULTS

The intended surgical aim was achieved successfully in all 3 cases. All patients showed a decline in serum creatinine levels. One patient who needed substitution therapy was free from dialysis 3 months after surgery. Additionally, blood pressure management was substantially reduced because uncontrolled peak systolic episodes were no longer observed and pharmacotherapeutic agents could be partially withdrawn.

CONCLUSIONS

Distal revascularization and surgical kidney recruitment via descendo-bifemoral bypass and renal artery revascularization is a promising option to treat complex obliterative arteriopathy.