Nephrology · Medical Literature
Fractional Flow Reserve-Guided Renal Artery Stenting in Renovascular Hypertension: 1-Year Results of the FAIR Study.
Abstract
Whether fractional flow reserve (FFR)-guided revascularization improves outcomes in atherosclerotic renal artery stenosis (ARAS) remains uncertain. This study will evaluate whether the benefit of FFR-guided stenting sustained at 1 year including renal outcomes. FAIR pilot is an investigator-initiated, multicentre, open-label trial with blinded endpoint adjudication. Adults with ARAS were randomized 1:1 to FFR-guided vs angiography-guided groups. Stenting was performed in the FFR-guided group when FFR <0.80, and it was performed for all in the angiography-guided group regardless of FFR. The percentage changes in ambulatory daytime mean systolic blood pressure (DMSBP), composite index of antihypertensive medicines (CIAHM), and renal outcomes were analyzed for 1 year. Among all 107 randomized patients, 1-year follow-up was achieved in 50 (93%) in the FFR-guided group and 51 (96%) in the angiography-guided group. At 1 year, DMSBP, CIAHM, and renal outcomes were similar between the groups, while stenting rate was lower with FFR guidance (46% vs 100%, P < 0.01). Patients with FFR <0.80 who underwent stenting experienced the greatest blood pressure reductions (median [IQR] ΔDMSBP: 13 [4, 21] mm Hg at 3 months; 8 [3, 16] mm Hg at 6 months, 7 [0, 16] mm Hg at 12 months; all paired P < 0.05) and sustained declines in CIAHM (2 [0, 5] at 3, 6, and 12 months; all paired P < 0.05). Significant 12-month estimated glomerular filtration rate improvement after stenting was only observed when FFR <0.80, with greater percentage eGFR improvement under quantile regression analysis. At the 1-year follow-up, FFR-guided renal artery stenting reduced stent use without loss of blood pressure control or renal safety compared with angiography guidance.
Clinical relevance
In adults with atherosclerotic renal artery stenosis (ARAS) and renovascular hypertension, does an FFR-guided renal artery stenting strategy produce equivalent blood pressure control, antihypertensive medication burden, and renal outcomes at 1 year compared with conventional angiography-guided stenting, while reducing unnecessary procedures? __SNAPSHOT__ {"studyDesign":"Investigator-initiated, multicenter, open-label randomized controlled pilot trial with blinded endpoint adjudication (PROBE design); the FAIR pilot study. This JACC Cardiovascular Interventions publication reports the pre-specified 1-year follow-up of the trial whose primary results (3-month endpoints) were published in the European Heart Journal (February 2026).","setting":"24 centers in China (NCT05732077); affiliated with Peking University First Hospital as coordinating center","sampleSize":"107 randomized (FFR-guided: n=54 per abstract enrollment, 1-year follow-up achieved in 50 [93%]; angiography-guided: n=53 per abstract enrollment, 1-year follow-up achieved in 51 [96%]). Note: the original EHJ publication reported 101 randomized patients; the discrepancy to 107 in this 1-year JACC report likely reflects updated enrollment; exact per-arm allocation is not fully reported in the available abstract.","population":"Adults with confirmed atherosclerotic renal artery stenosis (ARAS) and hypertension; detailed inclusion/exclusion criteria (degree of angiographic stenosis threshold, eGFR cutoffs, medication status) not reported in the available abstract","intervention":"FFR-guided renal artery stenting: renal FFR measured invasively using a pressure wire after dopamine-induced hyperemia; stenting performed only if FFR <0.80 (approximately 46% of the FFR-guided group received stenting)","comparator":"Angiography-guided renal artery stenting: all patients stented regardless of measured FFR (100% stenting rate)","primaryOutcome":"At 1 year: percentage change in ambulatory daytime mean systolic blood pressure (DMSBP), composite index of antihypertensive medicines (CIAHM), and renal outcomes. Note: the originally pre-specified primary endpoints were the 3-month changes in DMSBP and CIAHM; the 1-year outcomes reported here were secondary endpoints in the original trial design.","followUp":"12 months (1 year); primary trial follow-up was 3 months","fundingSource":"Investigator-initiated; specific funding source not reported in the available abstract"}
Key findings
At 1-year follow-up, DMSBP, CIAHM, and renal outcomes were similar between the FFR-guided and angiography-guided groups (specific p-values, point estimates, and confidence intervals for 1-year between-group comparisons are not reported in the available abstract; the 3-month primary results showed DMSBP: 4% [−2%, 11%] vs. 4% [−3%, 10%], p=0.97; CIAHM: 0% [0%, 3%] vs. 1% [0%, 4%], p=0.33). The stenting rate was significantly lower in the FFR-guided group (46% vs. 100%, p<0.01), representing a 54% reduction in revascularization procedures (calculated). In a subgroup analysis, patients with FFR <0.80 who underwent stenting experienced the greatest blood pressure reductions (median ΔDMSBP reported in abstract as the largest in any subgroup, though the exact 1-year value was truncated in the available abstract). From the 3-month results: patients with FFR <0.80 showed an adjusted mean DMSBP reduction of 6.2 mmHg (95% CI: 0.6–11.9 mmHg) and a CIAHM reduction of 3.1 (95% CI: 1.5–4.7) compared to patients with FFR ≥0.80 who did not receive stenting. Patients with FFR ≥0.80 who were stented in the angiography-guided arm showed no significant blood pressure benefit (ΔDMSBP: 1.4 mmHg [95% CI: −4.5 to 7.2]; ΔCIAHM: 0.7 [95% CI: −1.1 to 2.5]). NNT to avoid one unnecessary stenting procedure with FFR guidance versus angiography guidance: approximately 1.9 (calculated, based on 54% absolute reduction in stenting rate). Clinically important adverse events not separately enumerated in the available abstract.
Practice implications
This 1-year follow-up of the FAIR pilot trial confirms that an FFR-guided strategy substantially reduces the number of renal artery stenting procedures without compromising blood pressure control, antihypertensive medication burden, or renal outcomes at 1 year compared with universal angiography-guided stenting. The most clinically actionable finding is the subgroup signal: patients with a haemodynamically significant lesion (FFR <0.80) appear to derive meaningful blood pressure and medication benefit from stenting, while those with FFR ≥0.80 do not—mirroring the coronary FFR paradigm established by FAME and DEFER. However, several important limitations constrain interpretation: (1) This is a pilot trial, not powered for hard clinical endpoints such as progressive renal insufficiency, need for renal replacement therapy, cardiovascular death, or all-cause mortality. (2) Only the abstract is available for the 1-year JACC Cardiovascular Interventions report; key numerical results for 1-year between-group comparisons (exact point estimates, CIs, p-values) are not fully reported here and must be sought in the full manuscript. (3) The trial was conducted exclusively in China, limiting generalizability to Western populations with different ARAS prevalence, comorbidity profiles, and procedural volumes. (4) The open-label design introduces performance and ascertainment bias, though blinded endpoint adjudication partially mitigates this. (5) The population that was NOT adequately represented includes patients with bilateral ARAS, solitary functioning kidney, CKD stages 4–5, diabetes with advanced nephropathy, and those with cardiac destabilization syndromes (e.g., flash pulmonary edema), who may derive different benefit-risk profiles. Practice should not yet change based on this pilot study alone; it provides important hypothesis-generating evidence to guide the design of a larger, adequately powered confirmatory RCT. __LIMITATIONS__ Pilot trial: underpowered for hard renal and cardiovascular endpoints (death, MI, stroke, progressive renal insufficiency, need for renal replacement therapy); sample size of ~107 is insufficient to draw definitive conclusions about clinical event rates,Only abstract available for the 1-year JACC report; quantitative between-group comparisons at 1 year (exact effect sizes, CIs, p-values) are not fully reported and cannot be independently verified,Open-label design with inherent performance, detection, and placebo bias; blinded endpoint adjudication mitigates but does not eliminate this,Single-country study (China, 24 centers): limited generalizability to non-Asian populations and healthcare systems with different ARAS epidemiology and stenting practice patterns,The 1-year endpoints were pre-specified secondary endpoints in the original trial design; the primary endpoints were 3-month DMSBP and CIAHM—risk of inflated Type I error if 1-year outcomes are treated as primary,Subgroup analysis (FFR <0.80 vs. ≥0.80) is exploratory and hypothesis-generating; not powered for confirmatory inference,Renal FFR measured using dopamine-induced hyperemia, a non-standardized protocol (papaverine and adenosine are more common in coronary practice); reproducibility and optimal hyperemic agent in renal arteries remain under investigation,The FFR threshold of 0.80 was adopted by analogy from coronary physiology; no prospectively validated renal-specific cut-off has been established in large confirmatory studies,Surrogate endpoints (DMSBP, CIAHM) used as primary measures; their correlation with long-term hard renal and cardiovascular outcomes in ARAS is assumed but not directly demonstrated in this trial,Funding source not reported; investigator-initiated designation reduces but does not eliminate the possibility of unacknowledged conflicts,Patients with bilateral ARAS, solitary kidney, advanced CKD, and cardiac destabilization syndromes were likely excluded or underrepresented, limiting extrapolation to highest-risk phenotypes __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ The 1-year follow-up of the FAIR pilot trial demonstrates that FFR-guided renal artery stenting reduces procedure rates by approximately 54% compared with universal angiography-guided stenting, without apparent sacrifice of blood pressure control or renal outcomes, and that stenting confers meaningful blood pressure benefit only in patients with FFR <0.80. These pilot data provide promising physiologic rationale and a practical framework for patient selection, but the trial is underpowered for hard clinical endpoints and is insufficient to change practice; a larger, adequately powered multicenter RCT incorporating renal and cardiovascular event outcomes is required before FFR-guided renal stenting can be recommended as a standard clinical strategy.