Did renal artery stent placement fail in the Cardiovascular Outcomes with Renal Atherosclerotic Lesions (CORAL) study or did the CORAL Study Fail Renal Artery Stent Placement? The CORAL roll-in experience and the CORAL trials

Six Decades of History of Hypertension Research at the University of Toledo: Highlighting Pioneering Contributions in Biochemistry, Genetics, and Host-Microbiota Interactions

PURPOSE OF REVIEW

The study aims to capture the history and lineage of hypertension researchers from the University of Toledo in Ohio and showcase their collective scientific contributions dating from their initial discoveries of the physiology of adrenal and renal systems and genetics regulating blood pressure (BP) to its more contemporary contributions including microbiota and metabolomic links to BP regulation.

RECENT FINDINGS

The University of Toledo College of Medicine and Life Sciences (UTCOMLS), previously known as the Medical College of Ohio, has contributed significantly to our understanding of the etiology of hypertension. Two of the scientists, Patrick Mulrow and John Rapp from UTCOMLS, have been recognized with the highest honor, the Excellence in Hypertension award from the American Heart Association for their pioneering work on the physiology and genetics of hypertension, respectively. More recently, Bina Joe has continued their legacy in the basic sciences by uncovering previously unknown novel links between microbiota and metabolites to the etiology of hypertension, work that has been recognized by the American Heart Association with multiple awards. On the clinical research front, Christopher Cooper and colleagues lead the CORAL trials and contributed importantly to the investigations on renal artery stenosis treatment paradigms. Hypertension research at this institution has not only provided these pioneering insights, but also grown careers of scientists as leaders in academia as University Presidents and Deans of Medical Schools. Through the last decade, the university has expanded its commitment to Hypertension research as evident through the development of the Center for Hypertension and Precision Medicine led by Bina Joe as its founding Director. Hypertension being the top risk factor for cardiovascular diseases, which is the leading cause of human mortality, is an important area of research in multiple international universities. The UTCOMLS is one such university which, for the last 6 decades, has made significant contributions to our current understanding of hypertension. This review is a synthesis of this rich history. Additionally, it also serves as a collection of audio archives by more recent faculty who are also prominent leaders in the field of hypertension research, including John Rapp, Bina Joe, and Christopher Cooper, which are cataloged at Interviews .

Impact of Renal Function Trajectory on Renal Replacement Therapy and Mortality Risk after Renal Artery Revascularization

PURPOSE

To determine the impact of renal function trajectory, defined as the change in renal function over time before and after renal artery stent placement, on long-term risk for renal replacement therapy (RRT) and mortality.

MATERIALS AND METHODS

Estimated glomerular filtration rates (eGFRs) 6-12 months before renal artery stent placement, at the time of intervention, and 6-12 months after intervention were determined in 398 patients. The effect of eGFR change before and after renal artery stent placement was calculated. Cox proportional-hazards ratio was used to determine the risks for RRT and all-cause mortality.

RESULTS

The risk for RRT was significantly influenced by eGFR change from the time of intervention to follow-up at 6-12 month after treatment (P = .02). In addition, among patients with a postintervention eGFR ≤ 40 mL/min/1.73 m², for every 1 unit of eGFR increase, there was a significant decrease in RRT and all-cause mortality (P < .001 and P < .001, respectively). Secondary parameters that increased RRT risk included diabetes at the time of intervention (P = .03), increased baseline proteinuria (P < .001), and stage 4 or 5 chronic kidney disease (CKD; P = .01 and P = .003, respectively). Multivariate analysis demonstrated higher all-cause mortality rates among patients with diabetes at the time of intervention (P = .009).

CONCLUSIONS

Postintervention eGFR trajectory improvement approaching 40 mL/min/1.73 m² was associated with decreased RRT and mortality risk. These findings suggest that patients with advanced CKD and renal artery stenosis may benefit from revascularization regardless of their preinterventional renal function measurement.

Interaction between Albuminuria and Treatment Group Outcomes for Patients with Renal Artery Stenosis: The NITER Study

PURPOSE

To perform a post-hoc analysis of the Nephropathy Ischemic Therapy (NITER) trial, which enrolled patients with atherosclerotic renal artery stenosis, to evaluate whether medical therapy plus stent placement is superior to medical therapy alone in patients without elevated albuminuria.

MATERIALS AND METHODS

Data from 51 patients were analyzed and stratified into 2 cohorts by median urinary albumin (UAlb) levels: cohort 1 ("low albuminuria," UAlb ≤0.04 g/24h) and cohort 2 ("high albuminuria," UAlb >0.04g/24h). Interaction effect between treatment arms and UAlb cohorts was calculated using Cox regression analysis. Survival analysis was followed by test for effect size, power analysis, and construction of a Kaplan-Meier survival table.

RESULTS

At study completion, 13 patients had an outcome event: 6 (23%) from cohort 1 and 7 (28%) from cohort 2. Patients in cohort 1 had event-free survival of 83% at 3.9 ± 0.3 years from the primary endpoints of all-cause mortality, dialysis, and cardiovascular events when treated with interventional therapy, compared to 45% when treated with medical therapy alone (P = .501), which showed a 62% treatment effect for stent placement. In cohort 2, event-free survival rates were 64% for medical therapy versus 52% for medical plus interventional therapy (P = .64). Using Cox regression analysis, the interaction effect between treatment arms and UAlb cohorts was not significant (P = .32). The power of the study to detect an interaction effect, if one existed, was only 15%.

CONCLUSIONS

Inference cannot be drawn for similar populations because of inadequate sample size, but, in this sample, patients treated with stent placement who had low albuminuria had better outcomes than patients treated with medical therapy alone.

Relationship of Albuminuria and Renal Artery Stent Outcomes: Results From the CORAL Randomized Clinical Trial (Cardiovascular Outcomes With Renal Artery Lesions)

Randomized clinical trials have not shown an additional clinical benefit of renal artery stent placement over optimal medical therapy alone. However, studies of renal artery stent placement have not examined the relationship of albuminuria and treatment group outcomes. The CORAL study (Cardiovascular Outcomes in Renal Atherosclerotic Lesions) is a prospective clinical trial of 947 participants with atherosclerotic renal artery stenosis randomized to optimal medical therapy with or without renal artery stent which showed no treatment differences (3(5.8% and 35.1% event rate at mean 43-month follow-up). In a post hoc analysis, the study population was stratified by the median baseline urine albumin/creatinine ratio (n=826) and analyzed for the 5-year incidence of the primary end point (myocardial infarction, hospitalization for congestive heart failure, stroke, renal replacement therapy, progressive renal insufficiency, or cardiovascular disease- or kidney disease-related death), for each component of the primary end point, and overall survival. When baseline urine albumin/creatinine ratio was ≤ median (22.5 mg/g, n=413), renal artery stenting was associated with significantly better event-free survival from the primary composite end point (73% versus 59% at 5 years; P=0.02), cardiovascular disease-related death (93% versus 85%; P≤ 0.01), progressive renal insufficiency (91% versus 77%; P=0.03), and overall survival (89% versus 76%; P≤0.01), but not when baseline urine albumin/creatinine ratio was greater than median (n=413). These data suggest that low albuminuria may indicate a potentially large subgroup of those with renal artery stenosis that could experience improved event-free and overall-survival after renal artery stent placement plus optimal medical therapy compared with optimal medical therapy alone. Further research is needed to confirm these preliminary observations.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00081731.

Renal Artery Stent Outcomes: Effect of Baseline Blood Pressure, Stenosis Severity, and Translesion Pressure Gradient

BACKGROUND

Multiple randomized clinical trials comparing renal artery stent placement plus medical therapy with medical therapy alone have not shown any benefit of stent placement. However, debate continues whether patients with extreme pressure gradients, stenosis severity, or baseline blood pressure benefit from stent revascularization.

OBJECTIVES

The study sought to test the hypothesis that pressure gradients, stenosis severity, and/or baseline blood pressure affects outcomes after renal artery stent placement.

METHODS

Using data from 947 patients with a history of hypertension or chronic kidney disease from the largest randomized trial of renal artery stent placement, the CORAL (Cardiovascular Outcomes in Renal Atherosclerotic Lesions) study, we performed exploratory analyses to determine if subsets of patients experienced better outcomes after stent placement than the overall cohort. We examined baseline stenosis severity, systolic blood pressure, and translesion pressure gradient (peak systolic and mean) and performed interaction tests and Cox proportional hazards analyses for the occurrence of the primary endpoint through all follow-up, to examine the effect of these variables on outcomes by treatment group.

RESULTS

There were no statistically significant differences in outcomes based on the examined variables nor were there any consistent nonsignificant trends.

CONCLUSIONS

Based on data from the CORAL randomized trial, there is no evidence of a significant treatment effect of the renal artery stent procedure compared with medical therapy alone based on stenosis severity, level of systolic blood pressure elevation, or according to the magnitude of the trans-stenotic pressure gradient. (Benefits of Medical Therapy Plus Stenting for Renal Atherosclerotic Lesions [CORAL]; NCT00081731).