The cardiovascular outcomes in renal atherosclerotic lesions study and the future of renal artery stenting

Overcoming Diagnostic Dilemma and Optimizing Intervention with Optical Coherence Tomographic Guidance in an Angiographically Ambiguous Renal Artery Stenosis Due to Fibromuscular Dysplasia

With the advent of endovascular therapy, conventional angiography has replaced histology as a diagnostic gold standard for fibromuscular dysplasia (FMD). However, angiographic findings are not precisely diagnostic in isolated focal renal artery stenosis (RAS) in FMD. Optical coherence tomography (OCT) imaging by reflecting in vivo histology may improve the diagnostic accuracy in such cases. Restenosis following balloon angioplasty of RAS in FMD occurs frequently and often requires optimized reintervention. However, the role of OCT in the diagnostic evaluation of focal RAS in FMD and in optimizing the intervention is not well studied. We present a young female with resistant secondary hypertension due to bilateral focal RAS on angiography. In the absence of an angiographic string of beads appearance, the diagnoses remained uncertain. However, OCT imaging diagnosed a multifocal disease with characteristic changes of fibro-medial dysplasia, akin to its histological description in the literature. The patient underwent bilateral balloon angioplasty with good angiographic results. After one year on follow-up, relapse of uncontrolled systemic hypertension occurred due to bilateral restenosis. Despite a satisfactory repeat balloon angioplasty of the left-sided re-stenotic lesion, a significant residual pressure gradient persisted. Usage of OCT guided oversized balloon and stent safely achieved good results with complete resolution of the pressure gradient. Right renal artery stenosis required balloon angioplasty alone. She had complete resolution of hypertension without any medications at six months of follow-up. In conclusion, OCT can supplement other diagnostic modalities in providing a proper diagnosis in an angiographically ambiguous focal RAS in FMD. A persistent residual pressure gradient across the lesion despite good angiographic results may be optimized with OCT guidance during the intervention.

Is there still a role for renal artery stenting in the management of renovascular hypertension - A single-center experience and where do we stand?

BACKGROUND

Renal artery (RA) stenosis has been implicated in the pathophysiological mechanism for resistant hypertension. Despite the increasingly diagnosed frequency of hemodynamically significant lesions, the value of RA revascularization remains controversial. Our group had previously demonstrated significant blood pressure (BP) reduction in a retrospective cohort of appropriately selected patients undergoing RA stenting up to 18-months of follow-up. We herein present long-term clinical outcomes data 5-years post revascularization on 26 subjects who continued follow-up at our institution.

METHODS

Retrospective analysis was performed on subjects who underwent RA stenting at our institution for hemodynamically significant (≥70%) RA stenosis and systolic hypertension on ≥3 antihypertensive agents. Clinical outcome data for systolic blood pressure (SBP), diastolic blood pressure (DBP), creatinine level and number of antihypertensive drugs was assessed prior to and then later at 6-12 months and 3-5 years post RA stenting.

RESULTS

Mean age was 69 ± 9 years; 27% (7/26) were male. Median follow-up was 5.1 years. Blood pressure reduction was sustained at long-term follow-up (135/70 ± 18/11 mmHg) compared to initial reduction noted at 6-months (136/69 ± 16/8 mmHg; p ≤0.01 for both) and from baseline (162/80 ± 24/18 mmHg; p ≤0.001 for both). The number of antihypertensive agents also decreased from 4.1 ± 1.0 to 2.7 ± 2.1 (p = 0.002) at 6-months and was sustained at long-term follow-up, 3.4 ± 1.2 (p = 0.03) with no difference in renal function between short- and long-term follow-up compared to baseline.

CONCLUSIONS

This study shows sustained benefit of RA stenting in BP reduction in an appropriately selected cohort with significant stenosis ≥70% and uncontrolled hypertension on multiple medications on long-term follow-up.

Endovascular Treatment of Renal Artery Stenosis due to Fibromuscular Dysplasia - Is Stent Implantation Underused in this Circumstance?

Fibromuscular dysplasia (FMD) is a nonatherosclerotic and noninflammatory arterial disease that commonly affects the renal and carotid arteries. The primary target in treating patients with renal artery FMD is the control of blood pressure in order to prevent end-organ damage, which can be caused by poorly controlled hypertension. Invasive endovascular treatment should be taken into consideration both when hypertension cannot be controlled with medication. According to current opinion, hypertension attributed to renal artery FMD is often successfully treated solely with percutaneous renal balloon angioplasty (PRBA), with no requirement for stent implantation under most circumstances. However, an FMD recurrence after PRBA occurs frequently in these patients.