Evidence for Angiotensin II as a Naturally Existing Suppressor for the Guanylyl Cyclase A Receptor and Cyclic GMP Generation.

The natriuretic peptide system (NPS) and renin-angiotensin-aldosterone system (RAAS) function oppositely at multiple levels. While it has long been suspected that angiotensin II (ANGII) may directly suppress NPS activity, no clear evidence to date supports this notion. This study was designed to systematically investigate ANGII-NPS interaction in humans, in vivo, and in vitro. Circulating atrial, b-type, and c-type natriuretic peptides (ANP, BNP, CNP), cyclic guanosine monophosphate (cGMP), and ANGII were simultaneously investigated in 128 human subjects. Prompted hypothesis was validated in vivo to determine the influence of ANGII on ANP actions. The underlying mechanisms were further explored via in vitro approaches. In humans, ANGII demonstrated an inverse relationship with ANP, BNP, and cGMP. In regression models predicting cGMP, adding ANGII levels and the interaction term between ANGII and natriuretic peptides increased the predictive accuracy of the base models constructed with either ANP or BNP, but not CNP. Importantly, stratified correlation analysis further revealed a positive association between cGMP and ANP or BNP only in subjects with low, but not high, ANGII levels. In rats, co-infusion of ANGII even at a physiological dose attenuated cGMP generation mediated by ANP infusion. In vitro, we found the suppressive effect of ANGII on ANP-stimulated cGMP requires the presence of ANGII type-1 (AT1) receptor and mechanistically involves protein kinase C (PKC), as this suppression can be substantially rescued by either valsartan (AT1 blocker) or Go6983 (PKC inhibitor). Using surface plasmon resonance (SPR), we showed ANGII has low binding affinity to the guanylyl cyclase A (GC-A) receptor compared to ANP or BNP. Our study reveals ANGII is a natural suppressor for the cGMP-generating action of GC-A via AT1/PKC dependent manner and highlights the importance of dual-targeting RAAS and NPS in maximizing beneficial properties of natriuretic peptides in cardiovascular protection.

EVIDENCE FOR ANGIOTENSIN II AS A NATURALLY EXISTING SUPPRESSOR FOR THE NATRIURETIC PEPTIDE SYSTEM.

Background: Natriuretic peptide system (NPS) and renin angiotensin aldosterone system (RAAS) function oppositely at multiple levels. While it has long been suspected that angiotensin II (ANGII) may directly suppress NPS activity, no clear evidence to date support this notion. Objectives: This study was designed to systematically investigate ANGII-NPS interaction in humans, in vivo, and in vitro for translational insights. Methods: Circulating atrial, b-type, and c-type natriuretic peptides (ANP, BNP, CNP), cyclic guanosine monophosphate (cGMP), and ANGII were simultaneously investigated in 128 human subjects. Prompted hypothesis was validated in rat model to determine influence of ANGII on ANP actions. Multiple engineered HEK293 cells and surface plasmon resonance (SPR) technology were leveraged for mechanistic exploration. Results: In humans, ANGII showed inverse relationship with ANP, BNP, and cGMP. In regression models predicting cGMP, adding ANGII levels and interaction term between ANGII and natriuretic peptide increased predicting accuracy of base models constructed with either ANP or BNP, but not CNP. Importantly, stratified correlation analysis further revealed positive association between cGMP with ANP or BNP only in subjects with low, but not high, ANGII levels. In rats, co-infusion of ANGII even at physiological dose attenuated blood pressure reduction and cGMP generation triggered by ANP infusion. In vitro, we showed that the suppression effect of ANGII on ANP-stimulated cGMP requires the presence of ANGII type-1 (AT1) receptor and mechanistically involves protein kinase C (PKC), which can be substantially rescued by either valsartan (AT1 blocker) or Go6983 (PKC inhibitor). Using SPR, we showed ANGII has low affinity for particulate guanylyl cyclase A (GC-A) receptor binding compared to ANP or BNP. Conclusions: Our study reveals ANGII as a natural suppressor for cGMP-generating action of GC-A via AT1/PKC dependent manner and highlights importance of dual-targeting RAAS and NPS in maximizing beneficial properties of natriuretic peptides in cardiovascular disease.

Prognostic Value of Urinary and Plasma C-Type Natriuretic Peptide in Acute Decompensated Heart Failure.

OBJECTIVES: This study sought to characterize urinary and plasma C-type natriuretic peptide (CNP) in acute decompensated heart failure (ADHF) to define their relationship with clinical variables and to determine whether urinary and plasma CNP together add prognostic value. BACKGROUND: CNP is a protective hormone that is synthesized in the kidney and endothelium and possesses antiremodeling properties. Urinary and plasma CNP levels are elevated in pathophysiological conditions; however, their regulation and prognostic value in heart failure (HF) is unclear. METHODS: Urinary and plasma CNP were measured in 109 healthy subjects and 208 patients with ADHF; the 95th percentile of CNP values from healthy subjects established the normal contemporary cutoffs. Patients with ADHF were stratified based on urinary and plasma CNP levels for clinical characterization and the assessment of risk for adverse outcomes. RESULTS: There was no significant correlation between urinary and plasma CNP in both cohorts. Urinary and plasma CNP were significantly elevated in patients with ADHF, and both increased with disease severity and were positively correlated with plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP). Of the patients with ADHF, 23% had elevations in both urinary and plasma CNP, whereas 24% had normal CNP levels. During a median follow-up of 3 years, patients with elevated urinary and plasma CNP had a significantly higher risk of rehospitalization and/or death (HR: 1.79; P = 0.03) and rehospitalization (HR: 2.16; P = 0.01) after adjusting for age, sex, left ventricular ejection fraction, renal function, and plasma NT-proBNP. The C-statistic and integrated discrimination analyses further supported that the addition of urinary and plasma CNP to established risk models improved the prediction of adverse outcomes in patients with ADHF. CONCLUSIONS: Urinary and plasma CNP are differentially regulated in ADHF, and elevations in both provided independent prognostic value for predicting adverse outcomes.

Adverse clinical outcomes in patients undergoing both PCI and TAVR: Analysis from a pooled multi-center registry.

BACKGROUND: There is a paucity of data regarding the optimum timing of PCI in relation to TAVR. OBJECTIVE: We compared the major adverse cardiovascular and cerebrovascular events (MACCE) rates among patients who underwent percutaneous coronary intervention (PCI) before transcatheter aortic valve replacement (TAVR) with those who received PCI with/after TAVR. METHODS: In this multicenter study, we pooled all consecutive patients who underwent TAVR at three high volume centers. RESULTS: Among 3,982 patients who underwent TAVR, 327 (8%) patients underwent PCI within 1 year before TAVR, 38 (1%) had PCI the same day as TAVR and 15 (0.5%) had PCI within 2 months after TAVR. Overall, among patients who received both PCI and TAVR (n = 380), history of previous CABG (HR:0.501; p = .001), higher BMI at TAVR (HR:0.970; p = .038), and statin therapy after TAVR (HR:0.660, p = .037) were independently associated with lower MACCE while warfarin therapy after TAVR was associated with a higher risk of MACCE (HR:1.779, p = .017). Patients who received PCI within 1 year before TAVR had similar baseline demographics, STS scores, clinical risk factors when compared to patients receiving PCI with/after TAVR. Both groups were similar in PCI (Syntax Score, ACC/AHA lesion class) and TAVR (valve types, access) related variables. There were no significant differences in terms of MACCE (log rank p = .550), all-cause mortality (log rank p = .433), strokes (log rank p = .153), and repeat PCI (log rank p = .054) in patients who underwent PCI with/after TAVR when compared to patients who received PCI before TAVR. CONCLUSION: Among patients who underwent both PCI and TAVR, history of CABG, higher BMI, and statin therapy had lower, while those discharged on warfarin, had higher adverse event rates. Adverse events rates were similar regardless of timing of PCI.

Differential Regulation of ANP and BNP in Acute Decompensated Heart Failure: Deficiency of ANP.

OBJECTIVES: This study investigated the differential regulation of circulating atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) in patients with acute decompensated heart failure (ADHF) and tested the hypothesis that a relative deficiency of ANP exists in a subgroup of patients with ADHF. BACKGROUND: The endocrine heart releases the cardiac hormones ANP and BNP, which play a key role in cardiovascular (CV), renal, and metabolic homeostasis. In heart failure (HF), both plasma ANP and BNP are increased as a compensatory homeostatic response to myocardial overload. METHODS: ANP and BNP concentrations were measured in a small group of patients with ADHF (n = 112). To support this study's goal, a total of 129 healthy subjects were prospectively recruited to establish contemporary normal values for ANP and BNP. Plasma 3',5'cyclic guanosine monophosphate (cGMP), ejection fraction (EF), and body mass index (BMI) were measured in these subjects. RESULTS: In cases of ADHF, 74% of patients showed elevated ANP and BNP. Importantly, 26% of patients were characterized as having normal ANP (21% of this subgroup had normal ANP and elevated BNP). Cyclic GMP was lowest in the ADHF group with normal levels of ANP (p < 0.001), whereas BMI and EF were inversely related to ANP levels (p = 0.003). CONCLUSIONS: Among a subgroup of patients hospitalized with ADHF, the presence of an ANP deficiency is consistent with a differential regulation of ANP and BNP and suggests the existence of a potentially compromised compensatory cardiac endocrine response. These findings have implications for the pathophysiology, diagnostics, and therapeutics of human HF.

Pulmonary Venous Waveforms Predict Rehospitalization and Mortality After Percutaneous Mitral Valve Repair.

OBJECTIVES: In this study, the authors hypothesized that intraprocedural improvement of pulmonary venous (PV) waveforms are predictive of improved outcomes. In this report, they analyzed intraprocedural invasive and echocardiographic changes with respect to rehospitalization and mortality. BACKGROUND: The effects of hemodynamic changes during percutaneous mitral valve repair (PMVR) with MitraClip (Abbott Vascular, Santa Clara, California) are incompletely characterized. METHODS: The authors retrospectively reviewed records and intraprocedural transesophageal echocardiograms of 115 consecutive patients (age 76 ± 12 years) who underwent PMVR for mitral regurgitation (MR) from May 2013 to January 2017 at Emory University Hospital. They assessed intraprocedural PV waveforms for improvement in morphology, measured change in MR grade by semiquantitative methods, evaluated invasive changes in left atrial pressure (LAP) and V-wave, and compared with 30-day and 1-year rehospitalization and all-cause mortality. RESULTS: Ninety-three cases (80%) had PV waveforms before and after clip placement sufficient for analysis, of which 67 (73%) demonstrated intraprocedural improvement in PV morphology and 25 (27%) did not. At 24 months, 57 (85%) of those with PV improvement were living, compared with only 10 (40%) of those without improvement. Proportional hazards models demonstrated a significant survival advantage in those with PV improvement (hazard ratio [HR]: 0.28, 95% confidence interval [CI]: 0.08 to 0.93, p = 0.038). By multivariable analysis, PV improvement predicted reduced 1-year cardiac rehospitalization (odds ratio [OR]: 0.18, p = 0.044). Intraprocedural assessment of MR grade and invasive hemodynamics did not consistently predict mortality and rehospitalization. CONCLUSIONS: PV waveforms are important markers of procedural success after PMVR. Our data show intraprocedural PV waveforms may predict rehospitalization and mortality after PMVR. A larger, multicenter cohort will be important to clarify this relationship.

Repeat Pulmonary Valve Replacement: Similar Intermediate-Term Outcomes With Surgical and Transcatheter Procedures.

OBJECTIVES: This study compares 30-day, 1-year, and 3-year echocardiographic findings and clinical outcomes of transcatheter pulmonary valve-in-valve replacement (TPVR) and repeat surgical pulmonary valve replacement (SPVR). BACKGROUND: In patients with adult congenital heart disease and previous pulmonary valve replacement (PVR) who require redo PVR, it is unclear whether TPVR or repeat SPVR is the preferred strategy. METHODS: We retrospectively identified 66 patients (TPVR, n = 36; SPVR, n = 30) with bioprosthetic pulmonary valves (PVs) who underwent either TPVR or repeat SPVR at Emory Healthcare from January 2007 to August 2017. RESULTS: The TPVR cohort had fewer men and more patients with baseline New York Heart Association (NYHA) functional class III or IV. There was no difference in mortality, cardiovascular readmission, or post-procedural PV reintervention at 30 days, 1 year, or 3 years. Post-procedural echocardiographic findings showed no difference in mean PV gradients between the TPVR and SPVR groups at 30 days, 1 year, or 3 years. In the TPVR cohort, there was less right ventricular dysfunction at 30 days (2.9% vs. 46.7%; p < 0.01), despite higher baseline NYHA functional class in the SPVR cohort. CONCLUSIONS: In patients with bioprosthetic PV dysfunction who underwent either TPVR or SPVR, there was no difference in mortality, cardiovascular readmission, or repeat PV intervention at 30 days, 1 year, or 3 years. Additionally, TPVR and SPVR had similar intermediate-term PV longevity, with no difference in PV gradients or PVR. The TPVR cohort also had less right ventricular dysfunction at 30 days despite a higher baseline NYHA functional classification. These intermediate-term results suggest that TPVR may be an attractive alternative to SPVR in patients with previous bioprosthetic surgical PVs.

Contemporary evaluation of mitral regurgitation - 3D echocardiography, cardiac magnetic resonance, and procedural planning.

INTRODUCTION: Mitral regurgitation is one of the more common forms of valvular heart disease. Given the expansion of therapies for structural heart disease, new therapies for mitral regurgitation are emerging. An accurate description and classification of mitral disease is important to understand pathology and provide recommendations for therapy. Areas covered: In the modern evaluation of mitral regurgitation, 3-dimensional echocardiography (3DE) and cardiac magnetic resonance imaging (CMR) play important roles which overcome the prior limitations of 2-dimensional echocardiography. Specifically, an advanced evaluation with these techniques allows accurate characterization of the anatomic etiology of mitral regurgitation and quantification of severity. Furthermore, the role of 3DE during intraprocedural guidance, 'interventional echocardiography,' is expanding. Expert commentary: In our review, we demonstrate a complete diagnostic evaluation of mitral valve dysfunction by 3DE and CMR and describe current implications for invasive therapy and procedural guidance.