Patient-Level Pooled Analysis of Endovascular Ultrasound Renal Denervation or a Sham Procedure 6 Months After Medication Escalation: The RADIANCE Clinical Trial Program

BACKGROUND

The randomized, sham-controlled RADIANCE-HTN (A Study of the Recor Medical Paradise System in Clinical Hypertension) SOLO, RADIANCE-HTN TRIO, and RADIANCE II (A Study of the Recor Medical Paradise System in Stage II Hypertension) trials independently met their primary end point of a greater reduction in daytime ambulatory systolic blood pressure (SBP) 2 months after ultrasound renal denervation (uRDN) in patients with hypertension. To characterize the longer-term effectiveness and safety of uRDN versus sham at 6 months, after the blinded addition of antihypertensive treatments (AHTs), we pooled individual patient data across these 3 similarly designed trials.

METHODS

Patients with mild to moderate hypertension who were not on AHT or with hypertension resistant to a standardized combination triple AHT were randomized to uRDN (n=293) versus sham (n=213); they were to remain off of added AHT throughout 2 months of follow-up unless specified blood pressure (BP) criteria were exceeded. In each trial, if monthly home BP was ≥135/85 mm Hg from 2 to 5 months, standardized AHT was sequentially added to target home BP <135/85 mm Hg under blinding to initial treatment assignment. Six-month outcomes included baseline- and AHT-adjusted change in daytime ambulatory, home, and office SBP; change in AHT; and safety. Linear mixed regression models using all BP measurements and change in AHT from baseline through 6 months were used.

RESULTS

Patients (70% men) were 54.1±9.3 years of age with a baseline daytime ambulatory/home/office SBP of 150.5±9.8/151.0±12.4/155.5±14.4 mm Hg, respectively. From 2 to 6 months, BP decreased in both groups with AHT titration, but fewer uRDN patients were prescribed AHT (P=0.004), and fewer additional AHT were prescribed to uRDN patients versus sham patients (P=0.001). Whereas the unadjusted between-group difference in daytime ambulatory SBP was similar at 6 months, the baseline and medication-adjusted between-group difference at 6 months was -3.0 mm Hg (95% CI, -5.7, -0.2; P=0.033), in favor of uRDN+AHT. For home and office SBP, the adjusted between-group differences in favor of uRDN+AHT over 6 months were -5.4 mm Hg (-6.8, -4.0; P<0.001) and -5.2 mm Hg (-7.1, -3.3; P<0.001), respectively. There was no heterogeneity between trials. Safety outcomes were few and did not differ between groups.

CONCLUSIONS

This individual patient-data analysis of 506 patients included in the RADIANCE trials demonstrates the maintenance of BP-lowering efficacy of uRDN versus sham at 6 months, with fewer added AHTs.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifiers: NCT02649426 and NCT03614260.

Real-world experience with ultrasound renal denervation utilizing home blood pressure monitoring: the Global Paradise System registry study design

BACKGROUND

Hypertension is a major public health issue due to its association with cardiovascular disease risk. Despite the availability of effective antihypertensive drugs, rates of blood pressure (BP) control remain suboptimal. Renal denervation (RDN) has emerged as an effective non-pharmacological, device-based treatment option for patients with hypertension. The multicenter, single-arm, observational Global Paradise™ System (GPS) registry has been designed to examine the long-term safety and effectiveness of ultrasound RDN (uRDN) with the Paradise System in a large population of patients with hypertension.

METHODS

The study aims to enroll up to 3000 patients undergoing uRDN in routine clinical practice. Patients will be recruited over a 4-year period and followed for 5 years (at 3, 6, and 12 months after the uRDN procedure and annually thereafter). Standardized home BP measurements will be taken every 3 months with automatic upload to the cloud. Office and ambulatory BP and adverse events will be collected as per routine clinical practice. Quality-of-Life questionnaires will be used to capture patient-reported outcomes.

CONCLUSIONS

This observational registry will provide real-world information on the safety and effectiveness of uRDN in a large population of patients treated during routine clinical practice, and also allow for a better understanding of responses in prespecified subgroups. The focus on home BP in this registry is expected to improve completeness of long-term follow-up and provide unique insights into BP over time. Global Paradise System registry study design. ABP, ambulatory blood pressure; BP, blood pressure; FU, follow-up; M, month; OBP, office blood pressure.

Patient-Level Pooled Analysis of Ultrasound Renal Denervation in the Sham-Controlled RADIANCE II, RADIANCE-HTN SOLO, and RADIANCE-HTN TRIO Trials

Importance

Ultrasound renal denervation (uRDN) was shown to lower blood pressure (BP) in patients with uncontrolled hypertension (HTN). Establishing the magnitude and consistency of the uRDN effect across the HTN spectrum is clinically important.

Objective

To characterize the effectiveness and safety of uRDN vs a sham procedure from individual patient-level pooled data across uRDN trials including either patients with mild to moderate HTN on a background of no medications or with HTN resistant to standardized triple-combination therapy.

Data Sources

A Study of the ReCor Medical Paradise System in Clinical Hypertension (RADIANCE-HTN SOLO and TRIO) and A Study of the ReCor Medical Paradise System in Stage II Hypertension (RADIANCE II) trials.

Study Selection

Trials with similar designs, standardized operational implementation (medication standardization and blinding of both patients and physicians to treatment assignment), and follow-up.

Data Extraction and Synthesis

Pooled analysis using individual patient-level data using linear regression models to compare uRDN with sham across the trials.

Main Outcomes and Measures

The primary outcome was baseline-adjusted change in 2-month daytime ambulatory systolic BP (dASBP) between groups.

Results

A total of 506 patients were randomized in the 3 studies (uRDN, 293; sham, 213; mean [SD] age, 54.1 [9.3]; 354 male [70.0%]). After a 1-month medication stabilization period, dASBP was similar between the groups (mean [SD], uRDN, 150.3 [9.2] mm Hg; sham, 150.8 [10.5] mm Hg). At 2 months, dASBP decreased by 8.5 mm Hg to mean (SD) 141.8 (13.8) mm Hg among patients treated with uRDN and by 2.9 mm Hg to 147.9 (14.6) mm Hg among patients treated with a sham procedure (mean difference, -5.9; 95% CI, -8.1 to -3.8 mm Hg; P < .001 in favor of uRDN). BP decreases from baseline with uRDN vs sham were consistent across trials and across BP parameters (office SBP: -10.4 mm Hg vs -3.4 mm Hg; mean difference, -6.4 mm Hg; 95% CI, -9.1 to -3.6 mm Hg; home SBP: -8.4 mm Hg vs -1.4 mm Hg; mean difference, -6.8 mm Hg; 95% CI, -8.7 to -4.9 mm Hg, respectively). The BP reductions with uRDN vs sham were consistent across prespecified subgroups. Independent predictors of a larger BP response to uRDN were higher baseline BP and heart rate and the presence of orthostatic hypertension. No differences in early safety end points were observed between groups.

Conclusions and Relevance

Results of this patient-level pooled analysis suggest that BP reductions with uRDN were consistent across HTN severity in sham-controlled trials designed with a 2-month primary end point to standardize medications across randomized groups.

Trial Registration

ClinicalTrials.gov Identifier: NCT02649426 and NCT03614260.

Remote Cardiovascular Hypertension Program Enhanced Blood Pressure Control During the COVID-19 Pandemic

Background The COVID-19 pandemic disrupted traditional health care; one fallout was a drastic decrease in blood pressure (BP) assessment. We analyzed the pandemic's impact on our existing remote hypertension management program's effectiveness and adaptability. Methods and Results This retrospective observational analysis evaluated BP control in an entirely remote management program before and during the pandemic. A team of pharmacists, nurse practitioners, physicians, and nonlicensed navigators used an evidence-based clinical algorithm to optimize hypertensive treatment. The algorithm was adapted during the pandemic to simplify BP control. Overall, 1256 patients (605 enrolled in the 6 months before the pandemic shutdown in March 2020 and 651 in the 6 months after) were a median age of 63 years old, 57% female, and 38.2% non-White. Among enrolled patients with sustained hypertension, 51.1% reached BP goals. Within this group, rates of achieving goal BP improved to 94.6% during the pandemic from 75.8% prepandemic (P<0.0001). Mean baseline home BP was 141.7/81.9 mm Hg during the pandemic and 139.8/82.2 prepandemic, and fell ≈16/9 mm Hg in both periods (P<0.0001). Maintenance during the pandemic was achieved earlier (median 11.8 versus 19.6 weeks, P<0.0001), with more frequent monthly calls (8.2 versus 3.1, P<0.0001) and more monthly home BP recordings per patient (32.4 versus 18.9, P<0.0001), compared with the prepandemic period. Conclusions A remote clinical management program was successfully adapted and delivered significant improvements in BP control and increased home BP monitoring despite a nationally observed disruption of traditional hypertension care. Such programs have the potential to transform hypertension management and care delivery.

Endovascular Ultrasound Renal Denervation to Treat Hypertension: The RADIANCE II Randomized Clinical Trial

Importance

Two initial sham-controlled trials demonstrated that ultrasound renal denervation decreases blood pressure (BP) in patients with mild to moderate hypertension and hypertension that is resistant to treatment.

Objective

To study the efficacy and safety of ultrasound renal denervation without the confounding influence of antihypertensive medications in patients with hypertension.

Design, Setting, and Participants

Sham-controlled, randomized clinical trial with patients and outcome assessors blinded to treatment assignment that was conducted between January 14, 2019, and March 25, 2022, at 37 centers in the US and 24 centers in Europe, with randomization stratified by center. Patients aged 18 years to 75 years with hypertension (seated office systolic BP [SBP] ≥140 mm Hg and diastolic BP [DBP] ≥90 mm Hg despite taking up to 2 antihypertensive medications) were eligible if they had an ambulatory SBP/DBP of 135/85 mm Hg or greater and an SBP/DBP less than 170/105 mm Hg after a 4-week washout of their medications. Patients with an estimated glomerular filtration rate of 40 mL/min/1.73 m2 or greater and with suitable renal artery anatomy were randomized 2:1 to undergo ultrasound renal denervation or a sham procedure. Patients were to abstain from antihypertensive medications until the 2-month follow-up unless prespecified BP criteria were exceeded and were associated with clinical symptoms.

Interventions

Ultrasound renal denervation vs a sham procedure.

Main Outcomes and Measures

The primary efficacy outcome was the mean change in daytime ambulatory SBP at 2 months. The primary safety composite outcome of major adverse events included death, kidney failure, and major embolic, vascular, cardiovascular, cerebrovascular, and hypertensive events at 30 days and renal artery stenosis greater than 70% detected at 6 months. The secondary outcomes included mean change in 24-hour ambulatory SBP, home SBP, office SBP, and all DBP parameters at 2 months.

Results

Among 1038 eligible patients, 150 were randomized to ultrasound renal denervation and 74 to a sham procedure (mean age, 55 years [SD, 9.3 years]; 28.6% female; and 16.1% self-identified as Black or African American). The reduction in daytime ambulatory SBP was greater with ultrasound renal denervation (mean, -7.9 mm Hg [SD, 11.6 mm Hg]) vs the sham procedure (mean, -1.8 mm Hg [SD, 9.5 mm Hg]) (baseline-adjusted between-group difference, -6.3 mm Hg [95% CI, -9.3 to -3.2 mm Hg], P < .001), with a consistent effect of ultrasound renal denervation throughout the 24-hour circadian cycle. Among 7 secondary BP outcomes, 6 were significantly improved with ultrasound renal denervation vs the sham procedure. No major adverse events were reported in either group.

Conclusions and Relevance

In patients with hypertension, ultrasound renal denervation reduced daytime ambulatory SBP at 2 months in the absence of antihypertensive medications vs a sham procedure without postprocedural major adverse events.

Trial Registration

ClinicalTrials.gov Identifier: NCT03614260.

Results of a Remotely Delivered Hypertension and Lipid Program in More Than 10 000 Patients Across a Diverse Health Care Network

Importance

Blood pressure (BP) and cholesterol control remain challenging. Remote care can deliver more effective care outside of traditional clinician-patient settings but scaling and ensuring access to care among diverse populations remains elusive.

Objective

To implement and evaluate a remote hypertension and cholesterol management program across a diverse health care network.

Design, Setting, and Participants

Between January 2018 and July 2021, 20 454 patients in a large integrated health network were screened; 18 444 were approached, and 10 803 were enrolled in a comprehensive remote hypertension and cholesterol program (3658 patients with hypertension, 8103 patients with cholesterol, and 958 patients with both). A total of 1266 patients requested education only without medication titration. Enrolled patients received education, home BP device integration, and medication titration. Nonlicensed navigators and pharmacists, supported by cardiovascular clinicians, coordinated care using standardized algorithms, task management and automation software, and omnichannel communication. BP and laboratory test results were actively monitored.

Main Outcomes and Measures

Changes in BP and low-density lipoprotein cholesterol (LDL-C).

Results

The mean (SD) age among 10 803 patients was 65 (11.4) years; 6009 participants (56%) were female; 1321 (12%) identified as Black, 1190 (11%) as Hispanic, 7758 (72%) as White, and 1727 (16%) as another or multiple races (including American Indian or Alaska Native, Asian, Native Hawaiian or Other Pacific Islander, unknown, other, and declined to respond; consolidated owing to small numbers); and 142 (11%) reported a preferred language other than English. A total of 424 482 BP readings and 139 263 laboratory reports were collected. In the hypertension program, the mean (SD) office BP prior to enrollment was 150/83 (18/10) mm Hg, and the mean (SD) home BP was 145/83 (20/12) mm Hg. For those engaged in remote medication management, the mean (SD) clinic BP 6 and 12 months after enrollment decreased by 8.7/3.8 (21.4/12.4) and 9.7/5.2 (22.2/12.6) mm Hg, respectively. In the education-only cohort, BP changed by a mean (SD) -1.5/-0.7 (23.0/11.1) and by +0.2/-1.9 (30.3/11.2) mm Hg, respectively (P < .001 for between cohort difference). In the lipids program, patients in remote medication management experienced a reduction in LDL-C by a mean (SD) 35.4 (43.1) and 37.5 (43.9) mg/dL at 6 and 12 months, respectively, while the education-only cohort experienced a mean (SD) reduction in LDL-C of 9.3 (34.3) and 10.2 (35.5) mg/dL at 6 and 12 months, respectively (P < .001). Similar rates of enrollment and reductions in BP and lipids were observed across different racial, ethnic, and primary language groups.

Conclusions and Relevance

The results of this study indicate that a standardized remote BP and cholesterol management program may help optimize guideline-directed therapy at scale, reduce cardiovascular risk, and minimize the need for in-person visits among diverse populations.

A remote hypertension management program clinical algorithm

INTRODUCTION

Hypertension is the leading risk factor for death, affecting over one billion people worldwide, yet control rates are poor and stagnant. We developed a remote hypertension management program that leverages digitally transmitted home blood pressure (BP) measurements, algorithmic care pathways, and patient-navigator communications to aid patients in achieving guideline-directed BP goals.

METHODS

Patients with uncontrolled hypertension are identified through provider referrals and electronic health record screening aided by population health managers within the Mass General Brigham (MGB) health system. Non-licensed patient navigators supervised by pharmacists, nurse practitioners, and physicians engage and educate patients. Patients receive cellular or Bluetooth-enabled BP devices with which they monitor and transmit scheduled home BP readings. Evidence-based medication changes are made according to a custom hypertension algorithm approved within a collaborative drug therapy management (CDTM) agreement with MGB and implemented by pharmacists. Using patient-specific characteristics, we developed different pathways to optimize medication regimens. The renin-angiotensin-aldosterone system-blocker pathway prescribed ARBs/ACE inhibitors first for patients with diabetes, impaired renal function, and microalbuminuria; the standard pathway started patients on calcium channel blockers. Regimens were escalated frequently, adding thiazide-type diuretics, and including beta blockers and mineralocorticoid receptor antagonists if needed.

DISCUSSION

We have developed an algorithmic approach for the remote management of hypertension with demonstrated success. A focus on algorithmic decision-making streamlines tasks and responsibilities, easing the potential for scalability of this model. As the backbone of our remote management program, this clinical algorithm can improve BP control and innovate the management of hypertension in large populations.

Effects of Renal Denervation vs Sham in Resistant Hypertension After Medication Escalation: Prespecified Analysis at 6 Months of the RADIANCE-HTN TRIO Randomized Clinical Trial

Importance

Although early trials of endovascular renal denervation (RDN) for patients with resistant hypertension (RHTN) reported inconsistent results, ultrasound RDN (uRDN) was found to decrease blood pressure (BP) vs sham at 2 months in patients with RHTN taking stable background medications in the Study of the ReCor Medical Paradise System in Clinical Hypertension (RADIANCE-HTN TRIO) trial.

Objectives

To report the prespecified analysis of the persistence of the BP effects and safety of uRDN vs sham at 6 months in conjunction with escalating antihypertensive medications.

Design, Setting, and Participants

This randomized, sham-controlled, clinical trial with outcome assessors and patients blinded to treatment assignment, enrolled patients from March 11, 2016, to March 13, 2020. This was an international, multicenter study conducted in the US and Europe. Participants with daytime ambulatory BP of 135/85 mm Hg or higher after 4 weeks of single-pill triple-combination treatment (angiotensin-receptor blocker, calcium channel blocker, and thiazide diuretic) with estimated glomerular filtration rate (eGFR) of 40 mL/min/1.73 m2 or greater were randomly assigned to uRDN or sham with medications unchanged through 2 months. From 2 to 5 months, if monthly home BP was 135/85 mm Hg or higher, standardized stepped-care antihypertensive treatment starting with aldosterone antagonists was initiated under blinding to treatment assignment.

Interventions

uRDN vs sham procedure in conjunction with added medications to target BP control.

Main Outcomes and Measures

Six-month change in medications, change in daytime ambulatory systolic BP, change in home systolic BP adjusted for baseline BP and medications, and safety.

Results

A total of 65 of 69 participants in the uRDN group and 64 of 67 participants in the sham group (mean [SD] age, 52.4 [8.3] years; 104 male [80.6%]) with a mean (SD) eGFR of 81.5 (22.8) mL/min/1.73 m2 had 6-month daytime ambulatory BP measurements. Fewer medications were added in the uRDN group (mean [SD], 0.7 [1.0] medications) vs sham (mean [SD], 1.1 [1.1] medications; P = .045) and fewer patients in the uRDN group received aldosterone antagonists at 6 months (26 of 65 [40.0%] vs 39 of 64 [60.9%]; P = .02). Despite less intensive standardized stepped-care antihypertensive treatment, mean (SD) daytime ambulatory BP at 6 months was 138.3 (15.1) mm Hg with uRDN vs 139.0 (14.3) mm Hg with sham (additional decreases of -2.4 [16.6] vs -7.0 [16.7] mm Hg from month 2, respectively), whereas home SBP was lowered to a greater extent with uRDN by 4.3 mm Hg (95% CI, 0.5-8.1 mm Hg; P = .03) in a mixed model adjusting for baseline and number of medications. Adverse events were infrequent and similar between groups.

Conclusions and Relevance

In this study, in patients with RHTN initially randomly assigned to uRDN or a sham procedure and who had persistent elevation of BP at 2 months after the procedure, standardized stepped-care antihypertensive treatment escalation resulted in similar BP reduction in both groups at 6 months, with fewer additional medications required in the uRDN group.

Trial Registration

ClinicalTrials.gov Identifier: NCT02649426.

Guidance for the Interpretation of Continual Cuffless Blood Pressure Data for the Diagnosis and Management of Hypertension

Hypertension remains the leading risk factor for death worldwide. Despite its prevalence, success of blood pressure (BP) management efforts remains elusive, and part of the difficulty lies in the tool still used to diagnose, measure, and treat hypertension: the sphygmomanometer introduced by Samuel Siegfried Karl von Basch in 1867. In recent years, there has been an explosion of devices attempting to provide estimates of BP without a cuff, overcoming many limitations of cuff-based BP monitors. Unfortunately, the differences in underlying technologies between traditional BP cuffs and newer cuffless devices, as well as hesitancy of changing a well-implemented standard, still generate understandable skepticism about and reluctance to adopt cuffless BP monitors in clinical practice. This guidance document aims to navigate the scientific and medical communities through the types of cuffless devices and present examples of robust BP data collection which are better representations of a person's true BP. It highlights the differences between data collected by cuffless and traditional cuff-based devices and provides an initial framework of interpretation of the new cuffless datasets using, as an example, a CE-marked continual cuffless BP device (Aktiia BP Monitor, Aktiia, Switzerland). Demonstration of novel BP metrics, which have the potential to change the paradigm of hypertension diagnosis and treatment, are now possible for the first time with cuffless BP monitors that provide continual readings over long periods. Widespread adoption of continual cuffless BP monitors in healthcare will require a collaborative and thoughtful process, acknowledging that the transition from a legacy to a novel medical technology will be slow. Finally, this guidance concludes with a call to action to international scientific and expert associations to include cuffless BP monitors in original scientific research and in future versions of guidelines and standards.

Clinical Trial Design Principles and Outcomes Definitions for Device-Based Therapies for Hypertension: A Consensus Document From the Hypertension Academic Research Consortium

The clinical implications of hypertension in addition to a high prevalence of both uncontrolled blood pressure and medication nonadherence promote interest in developing device-based approaches to hypertension treatment. The expansion of device-based therapies and ongoing clinical trials underscores the need for consistency in trial design, conduct, and definitions of clinical study elements to permit trial comparability and data poolability. Standardizing methods of blood pressure assessment, effectiveness measures beyond blood pressure alone, and safety outcomes are paramount. The Hypertension Academic Research Consortium (HARC) document represents an integration of evolving evidence and consensus opinion among leading experts in cardiovascular medicine and hypertension research with regulatory perspectives on clinical trial design and methodology. The HARC document integrates the collective information among device-based therapies for hypertension to better address existing challenges and identify unmet needs for technologies proposed to treat the world’s leading cause of death and disability. Consistent with the Academic Research Consortium charter, this document proposes pragmatic consensus clinical design principles and outcomes definitions for studies aimed at evaluating device-based hypertension therapies.

Plasma renin and aldosterone concentrations related to endovascular ultrasound renal denervation in the RADIANCE-HTN SOLO trial

OBJECTIVE

The RADIANCE-HTN SOLO trial demonstrated a greater reduction in daytime ambulatory SBP at 2 months by endovascular ultrasound renal denervation than sham procedure. We hypothesized that plasma renin and aldosterone concentrations would be associated with the SBP response to renal denervation.

METHODS

Hypertensive patients were randomized to renal denervation (n = 74) or sham (n = 72) after a 4-week washout of antihypertensive medications. In a 53-patient subset, 2-month and 6-month plasma renin and aldosterone concentration were measured. Dietary sodium was not controlled.

RESULTS

Mean age of the 29 treatment and 24 sham patients was 54 years; 62% were men; 17% black. Daytime ambulatory SBP fell in the denervation but not the sham group at 2 months (-7.8 ± 10.7 vs. -0.1 ± 10.1 mmHg; P = 0.048). Baseline plasma renin and aldosterone concentrations were in the low-normal range, did not change significantly at 2 months in either group and did not predict response to renal denervation. At 6 months, after the addition of antihypertensive medications, there was a significant rise in renin in the sham but not the denervation group.

CONCLUSION

Although renal denervation but not sham resulted in a decrease in daytime ambulatory SBP at 2 months, renin and aldosterone concentrations did neither predict the BP response to renal denervation; nor did they fall after denervation. A rise in renin at 6 months in the sham group likely represents confounding from antihypertensive medications. Whether the BP-lowering effect of renal denervation depends on reducing local intrarenal renin release requires further study.

12-Month Results From the Unblinded Phase of the RADIANCE-HTN SOLO Trial of Ultrasound Renal Denervation

OBJECTIVES

This study reports the 12-month results of the RADIANCE-HTN (A Study of the ReCor Medical Paradise System in Clinical Hypertension) SOLO trial following unblinding of patients at 6 months.

BACKGROUND

The blood pressure (BP)-lowering efficacy and safety of endovascular ultrasound renal denervation (RDN) in the absence (2 months) and presence (6 months) of antihypertensive medications were previously reported.

METHODS

Patients with daytime ambulatory BP ≥135/85 mm Hg after 4 weeks off medication were randomized to RDN (n = 74) or sham (n = 72) and maintained off medication for 2 months. A standardized medication escalation protocol was instituted between 2 and 5 months (blinded phase). Between 6 and 12 months (unblinded phase), patients received antihypertensive medications at physicians' discretion. Outcomes at 12 months included medication burden, change in daytime ambulatory systolic BP (dASBP) and office or home systolic BP (SBP), visit-to-visit variability in SBP, and safety.

RESULTS

Sixty-five of 74 RDN patients and 67 of 72 sham patients had 12-month dASBP measurements. The proportion of patients on ≥2 medications (27.7% vs. 44.8%; p = 0.041), the number of medications (0 vs. 1.4; p = 0.015), and defined daily dose (1.4 vs. 2.2; p = 0.007) were less with RDN versus sham. The decrease in dASBP from baseline in the RDN group (-16.5 ± 12.9 mm Hg) remained stable at 12 months. The RDN versus sham adjusted difference at 12 months was -2.3 mm Hg (95% confidence interval [CI]: -5.9 to 1.3 mm Hg; p = 0.201) for dASBP, -6.3 mm Hg (95% CI: -11.1 to -1.5 mm Hg; p = 0.010) for office SBP, and -3.4 mm Hg (95% CI: -6.9 to 0.1 mm Hg; p = 0.062) for home SBP. Visit-to-visit variability in SBP was smaller in the RDN group. No renal artery injury was detected on computed tomographic or magnetic resonance angiography.

CONCLUSIONS

Despite unblinding, the BP-lowering effect of RDN was maintained at 12 months with fewer prescribed medications compared with sham.

Predictors of blood pressure response to ultrasound renal denervation in the RADIANCE-HTN SOLO study

The blood pressure (BP) lowering response to renal denervation (RDN) remains variable with about one-third of patients not responding to ultrasound or radiofrequency RDN. Identification of predictors of the BP response to RDN is needed to optimize patient selection for this therapy. This is a post-hoc analysis of the RADIANCE-HTN SOLO study. BP response to RDN was measured by the change in daytime ambulatory systolic blood pressure (dASBP) at 2 months post procedure. Univariate regression was used initially to assess potential predictors of outcome followed by multivariate regression analysis. In the univariate analysis, predictors of response to RDN were higher baseline daytime ambulatory diastolic blood pressure (dADBP), the use of antihypertensive medications at screening, and presence of orthostatic hypertension (OHTN) whilst the presence of untreated accessory arteries was a negative predictor of response. Multivariate analysis determined that dADBP and use of antihypertensive medications were predictors of response to RDN with a trend for OHTN to predict response. Obese females also appeared to be better responders to RDN in an interaction model. RDN is more effective in patients with elevated baseline dADBP and those with OHTN, suggesting increased peripheral vascular resistance secondary to heightened sympathetic tone. These assessments are easy to perform in clinical setting and may help in phenotyping patients who will respond better to RDN.

Euglycemic Diabetic Ketoacidosis With COVID-19 Infection in Patients With Type 2 Diabetes Taking SGLT2 Inhibitors

Objective

Diabetes mellitus is associated with poor outcomes in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Diabetic ketoacidosis (DKA) has also been reported to occur with this virus. A cluster of cases of euglycemic DKA (euDKA) was identified in patients with type 2 diabetes mellitus using sodium-glucose cotransporter-2 inhibitors (SGLT2is) who developed SARS-CoV-2 infection.

Methods

The cases were identified by the authors while providing clinical care, and details were collected.

Results

Five cases of euDKA, presenting with glucose levels <300 mg/dL, were identified over the course of 2 months by the endocrinology consult service. All patients had a history of type 2 diabetes mellitus with no known history of DKA. All were taking SGLT2is. Oral antihyperglycemic medications were stopped for all patients on admission. All received intravenous insulin infusion to treat DKA before being transitioned to a subcutaneous insulin regimen. SGLT2i use was discontinued for all patients who were discharged.

Conclusion

EuDKA has been seen in the setting of acute illness in patients using SGLT2is, but this cluster of cases suggests that there is a specific association with SARS-CoV-2 infection. In addition to the known risk of euDKA with SGLT2i use, coronavirus disease 2019-specific mechanisms may include a direct toxic effect of the virus on the pancreatic islets, an accelerated inflammatory response promoting ketosis, and the diuretic effect of SGLT2i in conjunction with anorexia and vomiting. It is crucial to counsel patients to stop SGLT2is when sick, especially if SARS-CoV-2 infection is suspected.

Development of an entirely remote, non-physician led hypertension management program

BACKGROUND

Hypertension remains poorly controlled on the population level. National rates of control, even when defined leniently by BP < 140/90 mm Hg, are only ~50%. As growing healthcare costs coincide with tighter blood pressure (BP) targets, innovative management programs are needed to maximize efficiency of care delivery and optimize control.

HYPOTHESIS

We aimed to develop a remote, navigator-led hypertension innovation program that would leverage algorithmic care pathways, home BP measurements and patient coaching to allow rapid and complete medication titration.

METHODS

A multidisciplinary group of clinical experts from subspecialties and primary care collaborated to develop an evidence-based clinical algorithm, designed to be automated and administered by non-licensed patient navigators. In the development stage, a prospective pilot cohort of 130 patients was managed by nurse practitioners and pharmacists to ensure efficacy and safety. Patients with clinic BP ≥ 140/90 mm Hg were enrolled and given a Bluetooth-enabled BP device. Home BPs were transmitted automatically into the electronic medical record. Medication titrations were performed by phone at biweekly intervals, based upon weekly average BP, until home BP was controlled at <135/85 mm Hg.

RESULTS

Eighty-one percent of all enrolled, and 91% of those patients who regularly measured home BP achieved goal, in an average of 7 weeks. Control was reached similarly across races, genders, and ages.

CONCLUSIONS

A home-based BP control program run by non-physicians can provide efficient, effective and rapid control, suggesting an innovative paradigm for hypertension management. This program is effective, sustainable, adaptable, and scalable to fit current and emerging national systems of healthcare.

Endovascular ultrasound renal denervation to treat hypertension (RADIANCE-HTN SOLO): a multicentre, international, single-blind, randomised, sham-controlled trial

BACKGROUND

Early studies suggest that radiofrequency-based renal denervation reduces blood pressure in patients with moderate hypertension. We investigated whether an alternative technology using endovascular ultrasound renal denervation reduces ambulatory blood pressure in patients with hypertension in the absence of antihypertensive medications.

METHODS

RADIANCE-HTN SOLO was a multicentre, international, single-blind, randomised, sham-controlled trial done at 21 centres in the USA and 18 in Europe. Patients with combined systolic-diastolic hypertension aged 18-75 years were eligible if they had ambulatory blood pressure greater than or equal to 135/85 mm Hg and less than 170/105 mm Hg after a 4-week discontinuation of up to two antihypertensive medications and had suitable renal artery anatomy. Patients were randomised (1:1) to undergo renal denervation with the Paradise system (ReCor Medical, Palo Alto, CA, USA) or a sham procedure consisting of renal angiography only. The randomisation sequence was computer generated and stratified by centres with randomised blocks of four or six and permutation of treatments within each block. Patients and outcome assessors were blinded to randomisation. The primary effectiveness endpoint was the change in daytime ambulatory systolic blood pressure at 2 months in the intention-to-treat population. Patients were to remain off antihypertensive medications throughout the 2 months of follow-up unless specified blood pressure criteria were exceeded. Major adverse events included all-cause mortality, renal failure, an embolic event with end-organ damage, renal artery or other major vascular complications requiring intervention, or admission to hospital for hypertensive crisis within 30 days and new renal artery stenosis within 6 months. This study is registered with ClinicalTrials.gov, number NCT02649426.

FINDINGS

Between March 28, 2016, and Dec 28, 2017, 803 patients were screened for eligibility and 146 were randomised to undergo renal denervation (n=74) or a sham procedure (n=72). The reduction in daytime ambulatory systolic blood pressure was greater with renal denervation (-8·5 mm Hg, SD 9·3) than with the sham procedure (-2·2 mm Hg, SD 10·0; baseline-adjusted difference between groups: -6·3 mm Hg, 95% CI -9·4 to -3·1, p=0·0001). No major adverse events were reported in either group.

INTERPRETATION

Compared with a sham procedure, endovascular ultrasound renal denervation reduced ambulatory blood pressure at 2 months in patients with combined systolic-diastolic hypertension in the absence of medications.

FUNDING

ReCor Medical.

Neurovascular coupling, cerebral white matter integrity, and response to cocoa in older people

OBJECTIVE

To investigate the relationship between neurovascular coupling and cognitive function in elderly individuals with vascular risk factors and to determine whether neurovascular coupling could be modified by cocoa consumption.

METHODS

Sixty older people (aged 72.9 ± 5.4 years) were studied in a parallel-arm, double-blind clinical trial of neurovascular coupling and cognition in response to 24 hours and 30 days of cocoa consumption. Cognitive measures included Mini-Mental State Examination and Trail Making Test A and B. Neurovascular coupling was measured from the beat-to-beat blood flow velocity responses in the middle cerebral arteries to the N-Back Task. In a subset of MRI-eligible participants, cerebral white matter structural integrity was also measured.

RESULTS

Neurovascular coupling was associated with Trails B scores (p = 0.002) and performance on the 2-Back Task. Higher neurovascular coupling was also associated with significantly higher fractional anisotropy in cerebral white matter hyperintensities (p = 0.02). Finally, 30 days of cocoa consumption was associated with increased neurovascular coupling (5.6% ± 7.2% vs -2.4% ± 4.8%; p = 0.001) and improved Trails B times (116 ± 78 seconds vs 167 ± 110 seconds; p = 0.007) in those with impaired neurovascular coupling at baseline.

CONCLUSION

There is a strong correlation between neurovascular coupling and cognitive function, and both can be improved by regular cocoa consumption in individuals with baseline impairments. Better neurovascular coupling is also associated with greater white matter structural integrity.

Habitual flavonoid intake and endothelial function in healthy humans

OBJECTIVE

Endothelial function, as measured by noninvasive techniques, is known to vary widely within populations. Our study was designed to test the hypothesis that this variation is determined in large part by a person's habitual dietary intake of flavonoids.

METHODS

This was an analytical study examining the relationship between endothelial function and dietary flavonoids in 19 healthy older adults (mean age 72 years). The study took place in the inpatient Clinical Research Center of the Brigham and Women's Hospital. Habitual flavonoid intake was assessed via a focused food frequency questionnaire. Endothelial function, measured as the reactive hyperemia response to 1 dose of flavonoid-rich cocoa, was recorded with a plethysmographic device via peripheral arterial tonometry (PAT).

RESULTS

Background flavonoid intake and the reactive hyperemia PAT (RH-PAT) response were significantly correlated (r = 0.7, p = 0.001); subjects with higher habitual flavonoid intake showed a significantly greater RH-PAT response than did lower consumers. PAT response to cocoa was also significantly correlated with simultaneous flavanol concentration in the blood (r = 0.5, p = 0.03).

CONCLUSION

Individual variation in endothelial function among healthy older people, measured as PAT response to flavonoid-rich cocoa, is highly dependent upon usual daily flavonoid consumption. These data raise the possibility that the consumption of fruits and vegetables dictates basal endothelial function, likely related to their flavonoid content and influence on nitric oxide.

Identification of risk drinking women: T-ACE screening tool or the medical record

BACKGROUND

Risk drinking for women is defined by the National Institute on Alcohol Abuse and Alcoholism (NIAAA) as >7 drinks per week or >3 drinks per occasion. This study compares the T-ACE screening tool and the medical record for identification of risk drinking by 611 women receiving outpatient treatment for diabetes, hypertension, infertility, or osteoporosis in Boston, Massachusetts, between February 2005 and May 2009.

METHODS

All subjects completed a diagnostic interview about their health habits, and medical records were abstracted. Calculations were weighted to reflect the oversampling of risk drinking women.

RESULTS

T-ACE-positive women (n = 419) had significantly more drinks per drinking day (2.1 vs. 1.6, p < 0.0001) and a trend toward more binges (6.3 vs. 3.8, p = 0.07) but similar percent drinking days and risk drinking weeks compared with those with negative screens (n = 192). Among the 521 (85%) medical records available, 46% acknowledged alcohol use, 25% denied use, and 29% were silent. The rates of abstinence among women were 2%, 17%, and 4%, respectively. Significantly more women were risk drinkers (63%) and had current alcohol use disorders (12%) when their medical records acknowledged alcohol use.

CONCLUSIONS

The main findings of this study are that neither the T-ACE nor the medical record was especially effective in identifying risk drinking by the women enrolled in the study. The identification of risky or heavy alcohol use in women, particularly if they have health problems exacerbated by alcohol, is desirable and represents an area of improvement for patients and providers alike.

Brief intervention for women with risky drinking and medical diagnoses: a randomized controlled trial

This is a randomized controlled trial of 511 eligible women treated for diabetes, hypertension, infertility, or osteoporosis on an outpatient basis to test the hypothesis that those randomized to a brief intervention (BI) will drink less than those in the control condition 12 months later. A secondary goal was to identify the characteristics associated with changes in drinking outcome. All 511 completed the initial alcohol assessment, and 96% completed the 12-month follow-up interview. Those receiving the BI also had 3- and 6-month interviews. Four outcomes were assessed: (a) mean drinks per drinking day, (b) percent drinking days, (c) binge episodes defined as four or more drinks per occasion, and (d) weeks of drinking exceeding the National Institute on Alcohol Abuse and Alcoholism sensible drinking limits. Overall, there were no differences in drinking outcome by treatment group. Characteristics associated with changes in drinking, however, were identified to provide possible direction for future investigation.

Brain blood flow and velocity: correlations between magnetic resonance imaging and transcranial Doppler sonography

OBJECTIVE

Because transcranial Doppler sonography (TCD) is unable to measure arterial diameter, it remains unproven whether the changes in cerebral blood velocity it measures are representative of changes in cerebral blood flow (CBF). Our study was designed to compare velocity changes with flow changes measured by two magnetic resonance imaging (MRI) techniques, perfusion MRI and arterial spin labeling (ASL), using flavanol-rich cocoa to induce CBF changes in healthy volunteers.

METHODS

We enrolled 20 healthy volunteers aged 62 to 80 years (mean, 73 years). Each was studied at baseline and after drinking standardized servings of cocoa for 7 to 14 days.

RESULTS

Changes in middle cerebral artery (MCA) flow by TCD were significantly correlated with changes in perfusion assessed by gadolinium-enhanced MRI (r = 0.63; P < .03). Measurements with ASL showed a stronger correlation with borderline significance.

CONCLUSIONS

Changes in flow velocity in the MCA associated with drinking cocoa were highly correlated with changes in CBF measured by the two MRI techniques using the tracer gadolinium and ASL. These results validate Doppler measurements of CBF velocity as representative assessments of CBF.

Plasma 25-hydroxyvitamin D and regulation of the renin-angiotensin system in humans

Vitamin D regulates the renin-angiotensin system (RAS) in experimental animals, but corresponding human data are limited. We examined the relation between plasma 25-hydroxyvitamin D and elements of the RAS in 184 normotensive individuals in high sodium balance; these included circulating levels of plasma renin activity and angiotensin II (Ang II) and the renal plasma flow response to infused Ang II, which is an indirect measure of the intrinsic RAS activity in the kidney. Compared with individuals with sufficient 25-hydroxyvitamin D levels (> or = 30.0 ng/mL), those with insufficiency (15.0 to 29.9 ng/mL) and deficiency (<15.0 ng/mL) had higher circulating Ang II levels (P for trend=0.03). Moreover, those with vitamin D deficiency had significantly blunted renal plasma flow responses to infused Ang II (mean decrease of 115 mL/min per 1.73 m(2) in renal plasma flow versus 145 mL/min per 1.73 m(2) among those with sufficient vitamin D levels; P for trend=0.009). Although plasma renin activity was higher among individuals with insufficient levels of vitamin D, the result was not statistically significant. These data suggest that low plasma 25-hydroxyvitamin D levels may result in upregulation of the RAS in otherwise healthy humans.

Renal plasma flow: glomerular filtration rate relationships in man during direct renin inhibition with aliskiren

We examined the relation between change in renal plasma flow (RPF) and change in glomerular filtration rate (GFR) in healthy humans on a low-salt diet during direct renin inhibition with aliskiren. We measured the renal hemodynamic response to acute dosing of 300mg aliskiren by mouth to 19 healthy normotensive subjects (age, 33+/-3 years; baseline RPF, 575+/-23; GFR, 138+/-14mL/min/1.73m(2)) on a low-sodium diet (10mmol/day). GFR and RPF were measured by the clearance of inulin and para-aminohippurate. There was a marked increase in average RPF (169+/-24mL/min/1.73m(2)) and a small rise in average GFR (1.4+/-5mL/min/1.73m(2)) from baseline in response to aliskiren. There was a clear correlation between the change in RPF and the change in GFR between subjects (r=0.65; P < .003). A substantial increase in RPF was accompanied by a rise in GFR. Dependence of GFR on RPF was identified in healthy humans after RPF rose significantly with aliskiren. The responsible mechanism likely involves intravascular oncotic pressure along the glomerular capillary resulting in greater surface area available for filtration.

Genetic polymorphisms and the risk of accelerated renal function decline in women

Background

Reduced glomerular filtration rate is an important predictor of cardiovascular disease and death. Genetic polymorphisms, particularly in genes involved in the renin-angiotensin system (RAS), may influence the rate of renal function decline.

Methodology/Principal Findings

We examined the relation between specific single nucleotide polymorphisms (SNPs), including those in the RAS, apolipoprotein E and alpha-adducin, and renal function decline assessed by estimated glomerular filtration rate (eGFR) over an 11-year period in 2578 Caucasian participants of the Nurses' Health Study. Logistic regression was used to examine the associations between genotype and risk of eGFR decline of ≥25%.

Results

After 11 years between creatinine measurements, the eGFR declined by ≥25% in 423 of 2578 (16%) women. The angiotensinogen (AGT) A-20C polymorphism was associated with a higher risk of renal function decline when two risk alleles were present than if one or no alleles were present (CC vs AA and AC) OR 1.83 (95% CI 1.02–3.26; p = 0.04). The angiotensin II type 1 receptor (AT₁R) A1166C polymorphism was marginally associated with a higher risk of renal function decline when two risk alleles were present (CC vs AA, OR = 1.41; 95% CI 0.98–2.01; p = 0.06). The alpha-adducin G460W polymorphism was associated with a lower risk of renal function decline when any number of risk alleles were present (WG vs GG, OR = 0.78, 95% CI 0.61–0.99, p = 0.04; WW vs GG, OR = 0.46; 95% CI 0.20–1.07, p = 0.07). Linear regression analysis with change in eGFR as the outcome showed a larger decline of 3.5 (95% CI 0.5 to 6.4, p = 0.02) ml/min/1.73 m² in AGT A-20C CC homozygotes. No other polymorphisms were significantly associated with renal function decline or absolute change in eGFR over the study period.

Conclusions

Genetic variants in the angiotensinogen, angiotensin II type 1 receptor and alpha-adducin genes may contribute to loss of renal function in the general female Caucasian population.

Vitamin D-mediated hypercalcemia and Cushing syndrome as manifestations of malignant pleural mesothelioma

OBJECTIVE

To report a case of coincident hypercalcemia and Cushing syndrome arising from mesothelioma.

METHODS

We describe the clinical, laboratory, imaging, and pathologic findings of a patient with malignant pleural mesothelioma and elucidate the underlying biologic mechanisms resulting in concurrent overexpression of steroid and polypeptide hormones.

RESULTS

A 62-year-old woman presented with chest discomfort and cough. Radiologic imaging revealed a diffuse pleural-based mass encasing the right lung. There was no invasion into the chest wall, diaphragm, or mediastinum, and there was no distant disease. Laboratory analyses documented hypercalcemia and Cushing syndrome, which were due to ectopic overproduction of 1,25-dihydroxyvitamin D (1,25[OH](2)D) and corticotropin. Surgical resection resulted in normocalcemia with normalization of serum 1,25(OH)(2)D and reduction in hypercortisolemia. The extrapleural pneumonectomy specimen revealed overexpression of the 1,25(OH)(2)D synthetic enzyme 25-hydroxyvitamin-D-1alpha-hydroxylase (1alpha-hydroxylase) and underexpression of the 1,25(OH)(2)D catabolic enzyme 24-hydroxylase. Immunohistochemistry and electron microscopy demonstrated corticotropin and secretory granules in the tumor tissue.

CONCLUSION

These findings support the evidence for a paracrine role of vitamin D in the resistance of the human host to antigen.

Renin-angiotensin system polymorphisms and risk of hypertension: influence of environmental factors

Renin-angiotensin system (RAS) polymorphisms have been studied as candidate risk factors for hypertension with inconsistent results, possibly due to heterogeneity among various environmental factors. We analyzed the association between RAS candidate gene polymorphisms and risk of hypertension among 2722 women and also explored whether these associations varied according to menopausal status, body mass index, and dietary factors. In a main-effects analysis of all 2722 women adjusted for age and race, homozygosity for the AT1R A1166C polymorphism was associated with hypertension (odds ratio, 1.35; 95% confidence interval [CI], 1.03-1.78). We also found that a novel nonsense polymorphism in the aminopeptidase-A gene was associated with hypertension among postmenopausal women (hazard ratio, 1.54; 95% CI, 1.01-2.37), women with inadequate calcium intake (hazard ratio, 2.47; 95% CI, 1.29-4.72) and, marginally, women with inadequate vitamin D intake. In addition, angiotensin-converting enzyme and AT1R A1166C polymorphisms were associated or marginally associated with incident hypertension among postmenopausal women and those with inadequate calcium and vitamin D intakes. These data suggest that demographic and dietary factors may influence the associations between RAS polymorphisms and hypertension and could explain heterogeneity in prior studies.

Aliskiren accumulates in Renin secretory granules and binds plasma prorenin

The vascular effects of aliskiren last longer than expected based on its half life, and this renin inhibitor has been reported to cause a greater renin rise than other renin-angiotensin system blockers. To investigate whether aliskiren accumulation in secretory granules contributes to these phenomena, renin-synthesizing mast cells were incubated with aliskiren, washed, and exposed to forskolin in medium without aliskiren (0.1 to 1000 nmol/L). (Pro)renin concentrations were measured by renin- and prorenin-specific immunoradiometric assays, and renin activity was measured by enzyme-kinetic assay. Without aliskiren, the culture medium predominantly contained prorenin, the cells exclusively stored renin, and forskolin doubled renin release. Aliskiren dose-dependently bound to (pro)renin in the medium and cell lysates and did not alter the effect of forskolin. The aliskiren concentrations required to bind prorenin were 1 to 2 orders of magnitude higher than those needed to bind renin. Blockade of cell lysate renin activity ranged from 27+/-15% to 79+/-5%, and these percentages were identical for the renin that was released by forskolin, indicating that they represented the same renin pool, ie, the renin storage granules. Comparison of renin and prorenin measurements in blood samples obtained from human volunteers treated with aliskiren, both before and after prorenin activation, revealed that <or=30% of prorenin was detected in renin-specific assays. In conclusion, aliskiren accumulates in renin granules, thus allowing long-lasting renin-angiotensin system blockade beyond the half-life of this drug. Aliskiren also binds to prorenin. This allows its detection as renin, and might explain, in part, the renin rise during renin inhibition.

Higher levels of albuminuria within the normal range predict incident hypertension

Higher levels of albumin excretion within the normal range are associated with cardiovascular disease in high-risk individuals. Whether incremental increases in urinary albumin excretion, even within the normal range, are associated with the development of hypertension in low-risk individuals is unknown. This study included 1065 postmenopausal women from the first Nurses' Health Study and 1114 premenopausal women from the second Nurses' Health Study who had an albumin/creatinine ratio <25 mg/g and who did not have diabetes or hypertension. Among the older women, 271 incident cases of hypertension occurred during 4 yr of follow-up, and among the younger women, 296 incident cases of hypertension occurred during 8 yr of follow-up. Cox proportional hazards regression was used to examine prospectively the association between the albumin/creatinine ratio and incident hypertension after adjustment for age, body mass index, estimated GFR, baseline BP, physical activity, smoking, and family history of hypertension. Participants who had an albumin/creatinine ratio in the highest quartile (4.34 to 24.17 mg/g for older women and 3.68 to 23.84 mg/g for younger women) were more likely to develop hypertension than those who had an albumin/creatinine ratio in the lowest quartile (hazard ratio 1.76 [95% confidence interval 1.21 to 2.56] and hazard ratio 1.35 [95% confidence interval 0.97 to 1.91] for older and younger women, respectively). Higher albumin/creatinine ratios, even within the normal range, are independently associated with increased risk for development of hypertension among women without diabetes. The definition of normal albumin excretion should be reevaluated.

Renal and hormonal responses to direct renin inhibition with aliskiren in healthy humans

BACKGROUND

Pharmacological interruption of the renin-angiotensin system focuses on optimization of blockade. As a measure of intrarenal renin activity, we have examined renal plasma flow (RPF) responses in a standardized protocol. Compared with responses with angiotensin-converting enzyme inhibition (rise in RPF approximately 95 mL x min(-1) x 1.73 m(-2)), greater renal vasodilation with angiotensin receptor blockers (approximately 145 mL x min(-1) x 1.73 m(-2)) suggested more effective blockade. We predicted that blockade with the direct oral renin inhibitor aliskiren would produce renal vascular responses exceeding those induced by angiotensin-converting enzyme inhibitors and angiotensin receptor blockers.

METHODS AND RESULTS

Twenty healthy normotensive subjects were studied on a low-sodium (10 mmol/d) diet, receiving separate escalating doses of aliskiren. Six additional subjects received captopril 25 mg as a low-sodium comparison and also received aliskiren on a high-sodium (200 mmol/d) diet. RPF was measured by clearance of para-aminohippurate. Aliskiren induced a remarkable dose-related renal vasodilation in low-sodium balance. The RPF response was maximal at the 600-mg dose (197+/-27 mL x min(-1) x 1.73 m(-2)) and exceeded responses to captopril (92+/-20 mL x min(-1) x 1.73 m(-2); P<0.01). Furthermore, significant residual vasodilation was observed 48 hours after each dose (P<0.01). The RPF response on a high-sodium diet was also higher than expected (47+/-17 mL x min(-1) x 1.73 m(-2)). Plasma renin activity and angiotensin levels were reduced in a dose-related manner. As another functional index of the effect of aliskiren, we found significant natriuresis on both diets.

CONCLUSIONS

Renal vasodilation in healthy people with the potent renin inhibitor aliskiren exceeded responses seen previously with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers. The effects were longer lasting and were associated with significant natriuresis. These results indicate that aliskiren may provide more complete and thus more effective blockade of the renin-angiotensin system.

Short- and long-term glycaemic control and the state of the renin system in type 1 diabetes mellitus

Renin system blockade in diabetes exerts a strong positive influence on complications, especially nephropathy. In hyperglycaemic diabetic subjects, however, blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors results in a marked rise in plasma renin. We investigated whether glycaemic fluctuations measured in hours, or those measured in weeks by Haemoglobin A(1C) (HbA(1C)) , influenced the plasma renin response to captopril. Fifty-four type 1 diabetic subjects were studied in high-salt balance. After an all night fast and in the supine position, baseline serum glucose level was drawn. Iv. glucose and insulin were then administered to keep serum glucose between 100 and 150 mg/dL (target). When target was reached, captopril 25 mg pre os was administered and plasma renin activity (PRA) and finger stick glucose were drawn, then serially every 45 minutes for 225 minutes. Baseline glucose and baseline PRA were drawn hours apart. Peak PRA corresponded to the renin level at peak captopril effect, 90' after administration. Renin response (RR) = peak PRA - baseline PRA. Correlation of baseline glucose with baseline PRA was weak (r=0.3, p=0.02), but strong with peak PRA (r=0.65; p=0.002). Drop in glucose had a weak, negative correlation with baseline PRA (r=-0.3, p=0.03) but a much stronger one with peak PRA (r=-0.7, p<0.0001). After adjustment for baseline PRA and baseline glucose, mean RR correlated strongly with mean drop in glucose (r=-0.72; p=0.008). Conversely, HbA1C correlated with none of the measures of renin system activation (r=0.05;p=0.7). In type 1 diabetic subjects, short-term hyperglycaemia, but not long-term glycaemic control, enhanced the RR to captopril.

Gender and the renal nitric oxide synthase system in healthy humans

BACKGROUND AND OBJECTIVES

It is widely known that men with kidney disease progress to ESRD at a much greater rate than do women. The mechanism for these gender differences is not clear, but reduced availability of nitric oxide is thought to contribute to the age-related decline in renal plasma flow observed in both healthy men and women. Animal models suggest that the renal vasculature of men may be significantly more dependent on nitric oxide than that of women.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Renal plasma flow response to the nonspecific nitric oxide synthase inhibitor nitro-L-arginine methyl ester (L-NAME) was measured by para-aminohippurate clearance technique in 21 healthy, normotensive (8 male, 13 female) individuals in balance on a high-salt diet.

RESULTS

There were striking differences between the genders in the renal hemodynamic response to L-NAME according to age, a difference that remained even after adjustment for other significant covariates. In men, the fall in renal plasma flow induced by L-NAME increased remarkably with increasing age. In women, there was no influence of age on the renovascular response to L-NAME. Neither age nor gender predicted the mean arterial pressure response to L-NAME.

CONCLUSIONS

The renal vasculature of men becomes more dependent on nitric oxide with age compared with that of women, suggesting that any renal disease that interferes with nitric oxide production may, over time, cause existent kidney damage to progress more quickly in men relative to women.

Prorenin and Angiotensin-Dependent Renal Vasoconstriction in Type 1 and Type 2 Diabetes

Prorenin is a powerful marker for risk of nephropathy and retinopathy in diabetes, but the responsible mechanism remains unclear. Studied were 35 patients with diabetes (18 with type 1 and 17 with type 2) and 69 age-matched healthy subjects with para-aminohippurate and inulin clearances and their response to captopril. All patients with diabetes had normal renal function and no microalbuminuria. Prorenin was calculated as the difference between total renin and active renin. Active renin level in patients with diabetes (11.6 +/- 0.9 microU/ml) was significantly lower than in normal subjects (14.5 +/- 1.3 microU/ml; P < 0.05); despite this, the renal vascular response to captopril was much larger (82.9 +/- 11.5 versus 13.6 +/- 5.8 ml/min per 1.73 m(2); P < 0.01). Prorenin in both patients with type 1 and type 2 diabetes (175.7 +/- 15.1 microU/ml) also was significantly higher than in normal subjects (128 +/- 5.8 microU/ml; P < 0.01). Active renin correlated with prorenin in normal subjects (r = 0.44, P = 0.0002), and this correlation was much more striking in patients with diabetes (r = 0.72, P = 0.0001). The active renin and prorenin correlation was identical in type 1 and type 2 diabetes. There was a clear correlation between plasma prorenin and the renovascular response to captopril in patients with diabetes (P < 0.01) but not in normal subjects (P > 0.13). The strong correlation between plasma prorenin concentration and the renovascular response to captopril in diabetes supports the hypothesis of a direct effect of prorenin, but the unanticipated high degree of correlation between plasma prorenin and active renin limits the conclusions that can be drawn.

Aging and vascular responses to flavanol-rich cocoa

OBJECTIVES

Strong evidence has secured aging as a powerful predictor of both cardiovascular risk and endothelial dysfunction, yet specific treatment is not available. We tested the hypothesis that vascular responsiveness to flavanol-rich cocoa increases with advancing age. We have previously shown that flavanol-rich cocoa induced peripheral vasodilation, improving endothelial function via a nitric oxide (NO)-dependent mechanism.

METHODS

We studied blood pressure and peripheral arterial responses to several days of cocoa in 15 young (< 50 years) and 19 older (> 50) healthy subjects.

RESULTS

The nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-arginine-methyl-ester (L-NAME) induced significant pressor responses following cocoa administration only among the older subjects: systolic blood pressure (SBP) rose 13 +/- 4 mmHg, diastolic blood pressure (DBP) 6 +/- 2 mmHg (P = 0.008 and 0.047, respectively); SBP was significantly higher in the older subjects (P < 0.05). Flow-mediated vasodilation, measured by tonometry in the finger, was enhanced with flavanol-rich cocoa in both groups, but significantly more so among the old (P = 0.01). Finally, basal pulse wave amplitude (PWA) followed a similar pattern. Four to six days of flavanol-rich cocoa caused a rise in PWA in both groups. At peak vasodilation following acute cocoa intake on the final day, both groups showed a further, significant rise in PWA. The response in the older subjects was more robust; P < 0.05. L-NAME significantly reversed dilation in both groups.

CONCLUSIONS

Flavanol-rich cocoa enhanced several measures of endothelial function to a greater degree among older than younger healthy subjects. Our data suggest that the NO-dependent vascular effects of flavanol-rich cocoa may be greater among older people, in whom endothelial function is more disturbed.

Cocoa Flavanols and Brain Perfusion

Foods and beverages rich in flavonoids are being heralded as potential preventive agents for a range of pathologic conditions, ranging from hypertension to coronary heart disease to stroke and dementia. We and others have demonstrated that short-term ingestion of cocoa, particularly rich in the subclass of flavonoids known as flavanols, induced a consistent and striking peripheral vasodilation in healthy people, improving endothelial function in a nitric oxide-dependent manner. The vasodilator response was reversed by N-nitro-L-arginine methyl ester, an arginine analog that blocks nitric oxide synthesis. Flavanol-poor cocoa induced much smaller responses. Because impairment of endothelial function is a nearly universal accompaniment of the aging process, we examined the peripheral vasodilator response to flavanol-rich cocoa in healthy older subjects. Observations point to a favorable response among the older. Together with peripheral vascular disease, cerebrovascular disease is responsible for significant mortality with advancing age. An association of decreased cerebral perfusion with dementia has been recently highlighted. The prospect of increasing cerebral perfusion with cocoa flavanols is extremely promising. Our still preliminary data hold out the promise that the cerebral blood supply in the elderly participates in the vasodilator response. With the modalities of transcranial Doppler and MRI, we have the capabilities of analyzing the potential benefits of flavanols on brain perfusion and, subsequently, on cognition.

Body mass index and angiotensin-dependent control of the renal circulation in healthy humans

Obesity is increasingly recognized as a risk factor for renal disease, but the mechanism is unclear. Renal plasma flow response to captopril, as an index of renin-angiotensin system activity, was measured by para-aminohippurate clearance technique in 100 healthy, normotensive subjects in balance on a high-salt diet. Of the 100 subjects, body mass index exceeded 25 in 56 and exceeded 30 in 22. The average vasodilator response to captopril was 27+/-7 mL/min per 1.73 m2 (P<0.0001). After adjustment for other predictors of the renal plasma flow response to captopril using a multivariate linear regression model, there was a highly significant relationship between age- and plasma renin activity-adjusted body mass index and the renal plasma flow response to captopril; however, a quadratic model provided a substantially better fit (r=0.55; P<0.0001; P=0.03 versus linear correlation). The strong association between increasing body mass index and angiotensin-dependent control of the renal circulation suggests that this may be a mechanism by which obesity contributes to renal disease. Weight loss should be considered in the overweight or obese patient for renal protection.

Oral contraceptives, angiotensin-dependent renal vasoconstriction, and risk of diabetic nephropathy

OBJECTIVE

Diabetes, the leading cause of end-stage renal disease in the U.S., is believed to involve activation of the renin angiotensin system (RAS) as a risk factor for nephropathy. RAS activation occurs in healthy women using oral contraceptives (OCs), but the effects of OC use on the diabetic kidney are unclear.

RESEARCH DESIGN AND METHODS

Renal plasma flow (RPF) response to captopril, as an index of RAS activity, was investigated in 92 women (41 nondiabetic OC nonusers, 10 nondiabetic OC users, 29 diabetic OC nonusers, and 12 diabetic OC users). Based on the hemodynamic findings, we examined the impact of OC use on the development of nephropathy as a post hoc analysis in an inception cohort of 114 female patients with newly diagnosed type 1 diabetes followed for a median of 20.7 years (range 1-24).

RESULTS

Nondiabetic OC nonusers showed minimal RPF vasodilator response to captopril (9 +/- 10 ml x min(-1) x 1.73 m(-2), P = 0.6). In comparison, nondiabetic OC users showed a significant increase (69 +/- 35 ml x min(-1) x 1.73 m(-2), P = 0.02) (P = 0.04 vs. nondiabetic OC nonusers). Diabetic OC nonusers demonstrated the anticipated vasodilator response (58 +/- 12 ml x min(-1) x 1.73 m(-2), P < 0.0001). Diabetic OC users showed the largest responses (84 +/- 12 ml x min(-1) x 1.73 m(-2), P = 0.002) (P = 0.04 vs. diabetic OC nonusers). Plasma renin activity did not vary with OC use (P = 0.3). The RPF responses to captopril and angiotensin receptor blocker were highly correlated (r = 0.72, P < 0.001), suggesting clear involvement of the RAS. In the observational study, 18% (6/33 [95% CI 4.3-32.1]) of OC users developed macroalbuminuria compared with 2% (2/81 [0-5.9]) of OC nonusers (P = 0.003, univariate analysis). After adjustment for known risk factors with a Cox regression model, OC use remained a predictor for the development of macroalbuminuria (relative risk 8.90 [95%CI 1.79-44.36], P = 0.008).

CONCLUSIONS

The strong association of OC use with angiotensin-dependent control of the renal circulation and the development of macroalbuminuria suggest that OC use may be a risk factor for diabetic nephropathy. Large prospective studies are required to further investigate this relationship.

Flavanols for cardiovascular health: the science behind the sweetness

PURPOSE OF REVIEW

Cardiovascular benefits for cocoa are being claimed in the scientific literature with growing intensity. To date, excitement over the potential health benefits of flavonoids has been driven mostly by epidemiological studies of tea and red wine, but raw cocoa contains specific flavonoids in concentrations far exceeding those from most other sources. Early evidence supports cocoa's enhancement of endothelial function via improvement of nitric oxide synthesis. However, many new studies have brought more confusion than clarity to the enterprise. This review provides guidelines for legitimate research in this promising field.

TOPICS OF DISCUSSION

Evidence generated from epidemiological studies, linking an increase in flavonoid ingestion to a reduction in cardiovascular events, is less convincing than data from controlled clinical trials. Whereas a few trials have shown evidence for an enhancement of endothelial function, inhibition of platelet adhesion and low-density lipoprotein oxidation, many studies have ignored scientific principles. Tremendous variability in cocoa processing, flavonoid content, measurement and dosing threatens the field. Valid research depends upon the precise identification and measurement of compounds of interest, which are probably the flavanols catechin and epicatechin, their oligomers and metabolites. These measures depend upon reliable methods of separation and quantification. Whether the monomers, dimers or larger flavanol oligomers, or their metabolites, are responsible for biological efficacy remains to be determined. Final questions surround bioavailability and dosing frequency.

CONCLUSIONS

Evidence is mounting to support cardiovascular health benefits from the consumption of flavanol-rich cocoa. This review hopes to illuminate sound scientific principles by which future research in the field can be guided.

Genetics of human hypertension

Hypertension is a complex genetic disorder caused by interplay between several "risk" genes and environmental factors (genetic heritability approximately 30%). Most genetic studies of hypertension use a candidate gene approach and two conclusions have been made: there is no association or linkage with the genes studied, or the hypertension phenotype is heterogeneous and subgroups with hypertension related to certain polymorphisms cannot be identified because of background noise. Studies using intermediate phenotypes suggest the latter is most likely. Another problem is the reliability of gene structure assessment: usually only one or two gene polymorphisms are assessed. The use of intermediate phenotypes and dense mapping of candidate genes would provide a better approach for identifying genotype-phenotype correlations, which might enable the use of genotypes to identify more-specific therapeutic and preventative measures for hypertensives.

Uric acid and the state of the intrarenal renin-angiotensin system in humans

BACKGROUND

Experimental hyperuricemia is marked by an activated intrarenal renin-angiotensin system (RAS). The renal vascular response to exogenous angiotensin II (Ang II) provides an indirect measure of intrarenal RAS activity. We tested the hypothesis that the serum uric acid concentration predicts the renal vascular response to Ang II.

METHODS

A total of 249 subjects in high sodium balance had the renal plasma flow (RPF) response to Ang II measured. Para-aminohippuric acid (PAH) clearance was used to estimate RPF. Multivariable regression analysis determined if the serum uric acid concentration independently predicts the RPF response to Ang II. Variables considered included age, gender, race, body mass index (BMI), hypertension status, blood pressure, basal RPF, creatinine clearance, serum insulin, serum glucose, serum high-density lipoprotein (HDL), serum triglycerides, and plasma renin activity (PRA).

RESULTS

Uric acid concentration negatively correlated with the RPF response to Ang II (r=-0.37, P < 0.001). In univariate analysis, age, BMI, hypertension, triglycerides, and blood pressure were negatively associated, and basal RPF, HDL, and female gender were positively associated with the RPF response to Ang II. In multivariable analysis, serum uric acid concentration independently predicted the RPF response to Ang II (beta=-5.3, P < 0.001).

CONCLUSION

Serum uric acid independently predicted blunted renal vascular responsiveness to Ang II, consistent with results from experimental hyperuricemia showing an activated intrarenal RAS. This could be due to a direct effect of uric acid or reflect a more fundamental renal process. These data may have relevance to the association of uric acid with risk for hypertension and nephropathy.

Renin Inhibition: What Are the Therapeutic Opportunities?

Blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers has become a crucial element in cardiovascular and renal medicine. This review evaluates the potential of renin inhibition as an adjunct to therapies that depend on renin system interruption.

Plasma aldosterone concentration in the patient with diabetes mellitus

BACKGROUND

Vascular injury at the microvascular and macrovascular levels plays a crucial role in the patient with diabetes mellitus. Evidence for renin-system activation in many patients with type 1 diabetes mellitus has raised the possibility that aldosterone-widely recognized as a contributor to vascular injury-could play a role.

METHODS

We examined the state of the renin-angiotensin-aldosterone system (RAAS) in 58 subjects with type 1 diabetes mellitus and 64 age-matched normal control subjects. All studies were performed on a fixed sodium (200 mmol/day) and potassium (100 mmol/day intake), and samples were drawn at 8:00 a.m. to avoid the influence of circadian rhythms.

RESULTS

The patient with diabetes mellitus showed an increase in plasma renin activity (PRA) (P < 0.01), plasma angiotensin II concentration (P < 0.01), and plasma aldosterone concentration (P < 0.001). A striking influence of the angiotensin receptor blocker, candesartan, on plasma aldosterone concentration in the patients with diabetes mellitus suggested strongly that renin-system activation is responsible for the elevated plasma aldosterone concentration.

CONCLUSION

Pharmacologic interruption of the effects of aldosterone at the tissue level could be especially useful in patients with diabetes mellitus. The dose of agents that block the renin-angiotensin system (RAS) should be adjusted to maximize the fall in plasma aldosterone concentration.

Flavanol-rich cocoa induces nitric-oxide-dependent vasodilation in healthy humans

BACKGROUND

Consumption of flavonoid-rich beverages, including tea and red wine, has been associated with a reduction in coronary events, but the physiological mechanism remains obscure. Cocoa can contain extraordinary concentrations of flavanols, a flavonoid subclass shown to activate nitric oxide synthase in vitro.

OBJECTIVE

To test the hypothesis that flavanol-rich cocoa induces nitric-oxide-dependent vasodilation in humans.

DESIGN

The study prospectively assessed the effects of Flavanol-rich cocoa, using both time and beverage controls. Participants were blinded to intervention; the endpoint was objective and blinded.

METHODS

Pulse wave amplitude was measured on the finger in 27 healthy people with a volume-sensitive validated calibrated plethysmograph, before and after 5 days of consumption of Flavanol-rich cocoa [821 mg of flavanols/day, quantitated as (-)-epicatechin, (+)-catechin, and related procyanidin oligomers]. The specific nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME) was infused intravenously on day 1, before cocoa, and on day 5, after an acute ingestion of cocoa.

RESULTS

Four days of flavanol-rich cocoa induced consistent and striking peripheral vasodilation (P = 0.009). On day 5, pulse wave amplitude exhibited a large additional acute response to cocoa (P = 0.01). L-NAME completely reversed this vasodilation (P = 0.004). In addition, intake of flavanol-rich cocoa augmented the vasodilator response to ischemia. Flavanol-poor cocoa induced much smaller responses (P = 0.005), and none was induced in the time-control study. Flavanol-rich cocoa also amplified the systemic pressor effects of L-NAME (P = 0.005).

CONCLUSION

In healthy humans, flavanol-rich cocoa induced vasodilation via activation of the nitric oxide system, providing a plausible mechanism for the protection that flavanol-rich foods induce against coronary events.

The renin-angiotensin system in blacks: active, passive, or what?

Plasma renin activity in blacks has been consistently reported to be lower than in whites. Many mechanisms for the low plasma renin activity have been proposed, including volume status, renal sodium handling, and the reduction of renin release. The status of the RAS is paramount in the regulation of salt and water balance and its implications in disease processes such as hypertension and renal failure. In this review, we present data to suggest that low systemic plasma renin activity in blacks may not be the primary abnormality, but rather the reflection of an overactive RAS at the tissue level in the kidney.

Glomerular hemodynamics and the renin-angiotensin system in patients with type 1 diabetes mellitus

BACKGROUND

Many studies have reported that blocking the renin-angiotensin-system (RAS) with an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin receptor blocker in the patient with diabetes mellitus leads to an increase in renal plasma flow (RPF), no change in glomerular filtration rate (GFR), and a fall in filtration fraction. This constellation is generally attributed to predominant efferent arteriolar dilation.

METHODS

This study examined the renal hemodynamic response to blocking the RAS with both captopril and candesartan on separate days in 31 patients with type 1 diabetes mellitus.

RESULTS

There was a wide range of changes in RPF and GFR in response to the two agents, each administered at the top of its dose-response range. The RPF response to the two agents was strongly concordant (r = 0.65; P < 0.001), as was the GFR response (r = 0.81; P < 0.001). Moreover, there was a strong correlation between the RPF response and the change in GFR with each agent (r = 0.83 and 0.66; P < 0.01). A significant rise in RPF was followed by a rise in GFR. The RPF dependency of GFR in the type 1 diabetics suggests strongly that glomerular filtration equilibrium exists in the glomeruli of the diabetic kidney: Simple notions of local control based on afferent:efferent arteriolar resistance ratios are too simplistic.

CONCLUSION

Our data suggest that the intrarenal RAS is activated in over 80% of patients with type 1 diabetes mellitus. Abundant evidence suggests that this activation predisposes to diabetic nephropathy.

Type 2 diabetes, obesity, and the renal response to blocking the renin system with irbesartan

AIM

Our recent studies revealed a striking but variable enhancement of renal vasodilator responses to blockers of the renin-angiotensin system in subjects with diabetes mellitus, possibly reflecting the level of intrarenal activation of the renin-angiotensin system, and thus a risk of nephropathy. As obesity is a common finding in diabetic individuals, and obesity has been linked to an increase in plasma angiotensinogen levels, we enrolled diabetic subjects with a wide range of body mass index (BMI) for this study.

METHODS

Twelve Type 2 diabetic subjects in balance on a low sodium diet participated after baseline renal plasma flow and glomerular filtration measurements were made. Each subject then received 150 mg irbesartan, and renal function was measured every 45 min for 4 h.

RESULTS

The average vasodilator response to irbesartan was 174 +/- 33 ml/min. No correlation was found between renal plasma flow response to irbesartan and duration of diabetes, baseline glucose, or HbA1c level. BMI, our measure of obesity, was highly correlated to the renal response to irbesartan (r = 0.7; P = 0.01).

CONCLUSIONS

Our findings suggest an important role for obesity in activating the intrarenal renin system, perhaps via production of angiotensinogen. BMI may be an indicator of risk of nephropathy.