Glucagon-like peptide-1 receptor agonist and the relation between metabolic effects and cardiovascular outcomes: insight into mechanisms of action

Background

Glucagon-like Peptide-1 receptor agonists (GLP-1RAs) have been shown to lower cardiovascular risk, and they are likely to reduce the incidence of all-cause and cardiovascular mortality in patients with type 2 diabetes. In this study-level analysis we investigated how metabolic and blood pressure changes are related to the reduction of cardiovascular events with GLP-1RAs.

Methods

We included seven randomized, placebo-controlled trials (ELIXA, LEADER, SUSTAIN-6, REWIND, EXSCEL, PIONEER 6, Harmony Outcomes) reporting incidence of one or more of the following outcomes: MACE, stroke, myocardial infarction, cardiovascular death, all-cause death, for a total of 56004 patients. A Pearson correlation analysis between logHR for the occurrence of outcome and placebo-corrected changes in Hb1Ac, systolic blood pressure and weight was performed.

Findings

Reduction of HbA1c level was significantly related to the reduction of MACE, Pearson R 0.86 (p=0.006) and stroke, Pearson R 0.79 (p=0.018). The reduction of weight instead, showed a robust correlation, not only with reduction of MACE, Pearson R 0.75 (p=0.032) and stroke, Pearson R 0.71 (p=0.047), but also with reduction of both cardiovascular death, Pearson R 0.95 (p=0.003; Picture 1) and all-cause death, Pearson R 0.91 (p=0.013). Reduction of SBP was significantly related to the reduction of both cardiovascular death, Pearson R 0.84 (p=0.036) and all-cause death, Pearson R 0.88 (p=0.020), but not of MACE.

Discussion

Mechanism of GLP-1RAs in preventing MACE is not fully understood. Other drugs that improve glycemic control did not showed convincing effect on cardiovascular outcome. Our finding prompts some considerations: both weight loss and control of HbA1c levels could play a role in MACE reduction. On the other hand, GLP1-RAs could act through other mechanisms and the metabolic effect could be a marker of the drug potency and dosage. Based on mechanistic studies, a theorized mechanism of cardiovascular benefit seen with GLP-1 RA is thought to be an anti-atherothrombotic and lipid plaque stabilization effect. This seems particularly convincing seeing the strong relationship of weight change and major events reduction. Notably, reduction in cardiovascular mortality and all-cause mortality was not related to the anti-hyperglycemic effect. Contrarily the body weight and SBP reduction were strongly related to both cardiovascular and all-cause mortality. These features could support the presumption of a hypothetic GLP1-RAs mechanism in modulation of lipidic profile and in RAAS inhibition, which have been already proved as beneficial for primary and secondary cardiovascular prevention.

Conclusion

Cardiovascular protection from GLP1-RAs is not primarily related to HbA1c reduction itself. Our data suggest that GLP-1RAs with the greater metabolic impact, such as liraglutide and semaglutide, should be used to treat diabetic patients to prevent MACE and CV death.

Funding Acknowledgement

Type of funding sources: None.

[Management of access site vascular complications in transcatheter aortic valve implantation]

Since its advent, transcatheter aortic valve implantation (TAVI) has experienced a continuous expansion, thanks to extraordinary clinical results and to the dramatic increase of safety, enabled by improvements of prosthesis and delivery systems, refinement of implantation techniques, increasing operator experience, and use of computed tomography scan for procedural planning. However, complications rates are still not negligible. As vascular complications, and, particularly, access-related complications are among the most frequent adverse events, all TAVI operators should know how to prevent and how to manage those potentially catastrophic situations. Here we provide an overview of the most frequent access site vascular complications and the respective treatment options.

Predictors and outcome of contrast-induced acute kidney injury in older patients presenting with acute coronary syndrome

Background

The number of older patients presenting with acute coronary syndrome (ACS) is increasing. Routine percutaneous coronary intervention (PCI) is performed in order to improve outcome, but comorbidities associated with aging lead to a higher risk of treatment complications. Contrast-induced acute kidney injury (CI-AKI) represents potential harm in older and frail patients, but its impact on long term prognosis is not clear.

Purpose

To evaluate occurrence, predictors, and impact on long term outcome of CI-AKI in elderly patients presenting with ACS.

Methods

A prospective cohort of 392 older (≥70 years) ACS patients who underwent coronary angiography was enrolled. CI-AKI was defined as a serum creatinine increase at least ≥0.3 mg/dl in 48 h or at least ≥50% in 7 days. According to our department protocol, prophylactic hydration was performed to all patients with isotonic saline, given intravenously at a rate of 1 ml/kg body weight/h (0.5 ml/kg for patients with left ventricular ejection fraction <35%) for 12 h before (unless for emergent patients) and 24 h after PCI. Median follow up was 4 [3.0–4.1] years. Long term adverse outcomes include all-cause mortality and any hospitalization for cardiovascular causes (ACS, heart failure, arrhythmia, cerebrovascular accident).

Results

CI-AKI was observed in 72 patients (18.4%). Among patients who developed or not CI-AKI, no difference was found between clinical presentation (Non-ST segment elevation myocardial infarction (NSTEMI) vs. STEMI), left ventricular ejection fraction and multivessel coronary disease. Estimated glomerular filtration rate (odd ratio (OR) 3.59, confidence interval (CI) 1.79–7.20, p<0.001), contrast media volume (OR 1.006, CI 1.002–1.009, P=0.001), white blood cells (OR 1.18, CI 1.10–1.27, p<0.001), haemoglobin level (OR 0.81, CI 0.70–0.94, p=0.005) and chronic obstructive pulmonary disease (OR=5.37, CI 2.24–12.90, p<0.001) were independent predictors for CI-AKI. Patients with CI-AKI presented increased mortality rate both at 30-days (2.7% vs 0%, p=0.038) and at 4-years follow-up (all cause death 23.6 vs. 11.6%, p=0.013) (Figure 1: long term adverse outcomes). Multivariable Cox proportional hazards analysis revealed that diabetes (hazard ratio, HR 1.99, CI 1.33–2.97, p=0.001), atrial fibrillation (HR 2.49, CI 1.59–3.91, p<0.001), Killip class >1 (HR 2.20, CI 1.32–3.67, p=0.003) and haemoglobin level (HR 0.84, CI 0.76–0.92, p<0.001) were independently associated with adverse outcome, while CI-AKI represent a risk factor only at univariate analysis.

Conclusions

CI-AKI is a common complication among older adults undergoing coronary angiography for ACS. Patients who developed CI-AKI had worse outcome at long term follow-up. Actually, the occurrence of CI-AKI was not identified as an independent predictor for long-term adverse outcome, while it may represent a marker of severity of comorbidity and consequent poor prognosis, rather than a causal agent itself.

Figure 1. Kaplan-Maier Curve

Funding Acknowledgement

Type of funding source: None

[Early and mid-term results of the transapical aortic valve Symetis Acurate TA: a viable solution in high-risk patients with severe vascular disease]

BACKGROUND

Aortic valve stenosis is the most common valvular disease in the elderly. Transcatheter aortic valve implantation represents a viable alternative to conventional aortic valve replacement. In our Department, the transapical approach is the preferred method in patients with severe peripheral vascular disease. The aim of this study was to analyze the early and midterm results of Symetis Acurate TA implantation in our series.

METHODS

From June 2013 to January 2017, 21 patients with severe peripheral vascular disease (11 male, mean age 78 ± 2.8 years) underwent transapical implantation of the Symetis Acurate TA device. Mean logistic EuroSCORE I was 21.9 ± 8.6, mean left ventricular ejection fraction was 51.9 ± 12.2%, and mean aortic gradient was 46.7 ± 12.3 mmHg. Valve implantation was performed through a left anterior minithoracotomy. Patients were followed up on a regular basis. Cardiac echocardiographic assessment was performed at 6 months post-implantation.

RESULTS

Valve implantation was successful in all patients. Valve sizes were as follows: 7 size S, 6 size M, and 8 size L. Two patients died before hospital discharge (9.5%). Among survivors, 2 patients showed more than mild aortic regurgitation at discharge. Mean aortic gradient was 13.1 ± 4.3 mmHg (p<0.01). Median follow-up was 11.3 months. Mean NYHA class at follow-up was 1.9 ± 0.4 (p<0.05). Mean actuarial survival was 80%.

CONCLUSIONS

Our series, even if small, demonstrates that transapical implantation of the Symetis Acurate TA device represents a viable solution in patients with severe peripheral vascular disease carrying a high operative risk. The relatively high operative mortality may be attributable to the learning curve of our team.

Metabolic syndrome does not increase angiographic restenosis rates after drug-eluting stent implantation

Metabolic syndrome (MS) is associated with an increased risk of coronary heart disease, stroke, and cardiovascular mortality; but its effect on patients undergoing cardiac revascularization is still unclear. Robust evidence demonstrates that diabetes mellitus and insulin resistance are among the main risk factors for restenosis in patients requiring percutaneous myocardial revascularization. The recent advent of drug-eluting stents (DESs) has significantly reduced the incidence of restenosis compared with bare-metal stents, both in nondiabetic and in diabetic patients. The aim of the study was to evaluate the effect of MS on the risk of binary restenosis in DES implant recipients. One hundred eighty-nine recipients of successful DES implants performed between January and March 2005 for stable coronary artery disease underwent 1-year clinical and angiographic follow-up. Body mass index (BMI), blood pressure, fasting blood glucose, and lipid profile were determined. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria, with the waist criterion being substituted by a BMI>or=28.8 kg/m2. Metabolic and anthropometric information for MS diagnosis was available for 148 of 189 patients; 87 of 148 patients (58%) had MS. Patients with MS had higher BMI (28.4+/-3.8 vs 26+/-2.7 kg/m2, P<.0001), systolic blood pressure (133+/-14 vs 124+/-14 mm Hg, P=.0004), and fasting glucose (113+/-37 vs 92+/-17 mg/dL, P<.0001). They also had higher serum triglycerides (154+/-94 vs 113+/-43, P=.0018) and lower high-density lipoprotein cholesterol levels (39+/-9 vs 46+/-10, P<.0001). Rates of restenosis (10.5% vs 8.1%, P=not significant [NS]), target vessel revascularization (10.5% vs 11.3%, P=NS), and major adverse cardiac events (11.6% vs 14.5%, P=NS) were not significantly different in patients with MS compared with those without MS, nor was any association found between increased end point risk and presence of MS. When patients were subdivided into 6 subgroups by the presence of 0, 1, 2, 3, 4, or 5 of the MS components, restenosis rates were not significantly different among subgroups. In conclusion, MS is not associated with higher rates of restenosis, target vessel revascularization, or major adverse cardiac events; and no additional MS feature was associated with an increased risk.

Cardiovascular phenotype of young adults and angiotensinogen alleles

OBJECTIVES AND DESIGN

Angiotensinogen (AGT) gene variants influence angiotensinogen plasma levels in children and young adults. The angiotensinogen promoter (-6)A variant facilitates gene transcription in human tissues and it has been associated with high blood pressure in older adults. A young adult population can be used as a model to study genotype/phenotype associations between AGT (-6) variants and cardiovascular variables.

METHODS AND RESULTS

Anthropometric measurements, blood pressure and heart rate were taken in 422 white Caucasian students (mean age 23.5 years, SD 2.5 years). Family history for hypertension, physical activity and smoking history were evaluated. Left ventricular variables were measured by echocardiography. Carotid artery wall intimal-media thickness (IMT) was measured by high resolution sonography and digitalized morphometry. The AGT G(-6)A alleles were evaluated by mutagenically separated polymerase chain reaction controlled by direct sequencing. No significant associations were found between angiotensinogen genotype and blood pressure, cardiac variables [except for deceleration time in females which increased with the number of (-6)A alleles] and IMT. Allele frequencies were similar between the first and third tertile of blood pressure and left ventricular mass, and were also similar between negative or positive family history for hypertension (the last group having significantly higher systolic blood pressure in males, P = 0.04 and diastolic blood pressure in females, P < 0.01). Moreover, no relevant interaction on the cardiovascular variables was found between AGT genotype and body mass index.

CONCLUSIONS

The angiotensinogen G(-6)A variants do not affect cardiovascular parameters in young adults, but an effect of this polymorphism on cardiovascular phenotype (and hypertension) in older adults cannot be excluded. Additional factors, associated with ageing, should be present to unleash the supposed unfavourable potential of the (-6)A angiotensinogen variant.

A novel promoter variant of the natriuretic peptide clearance receptor gene is associated with lower atrial natriuretic peptide and higher blood pressure in obese hypertensives

OBJECTIVE AND DESIGN

The clearance receptor for natriuretic peptides (NPRC), a candidate gene for essential hypertension, is highly expressed in adipose tissue, where is nutritionally regulated. The objectives of the present study were to sequence the human 5'-flanking regulatory region of NPRC, to identify allelic variants and their frequencies, and to study the genotype/phenotype correlation in hypertensive patients.

METHODS AND RESULTS

Using polymerase chain reaction (PCR) and direct automated sequencing, a biallelic (A/C) polymorphism was detected at position -55 in a conserved promoter element named P1. The novel C(-55) variant makes the promoter sequence identical to the mouse gene and introduces a second Hgal site in the amplified DNA, allowing the genotyping of a large number of subjects. In a random sample of 232 white Caucasians the C(-55) allele was more commonly found (81.7% of all alleles) with 155 CC (66.8%), 69 AC (29.7%) and only eight AA (3.5%) genotypes. Atrial natriuretic peptide (ANP) levels were determined in 84 patients with essential hypertension. In the presence of obesity (body mass index (BMI) > or = 30 kg/m2) the homozygous CC hypertensives (n = 21) had significantly lower plasma ANP (33.6 +/- 11.1 pg/ml) compared with the AC patients (n = 11; 46.8 +/- 15.9 pg/ml; P = 0.01), whereas systolic blood pressure (SBP) and mean blood pressure (MBP) had the opposite association (SBP 163.9 +/- 18.7 versus 150.9 +/- 12.9 and MBP 123.3 +/- 12 versus 114.5 +/- 5.9 mmHg; P< 0.05). The difference in ANP levels were also present when overweight patients (BMI > or = 27 kg/m2) were considered.

CONCLUSION

A common 'ancestral' C(-55) variant of the NPRC P1 promoter is associated with lower ANP levels and higher SBP and MBP in obese hypertensives. The C(-55) variant, in the presence of increased adiposity, might reduce plasma ANP through increased NPRC-mediated ANP clearance, contributing to higher blood pressure.

Low calorie diet enhances renal, hemodynamic, and humoral effects of exogenous atrial natriuretic peptide in obese hypertensives

The expression of the natriuretic peptide clearance receptor is abundant in human and rat adipose tissue, where it is specifically inhibited by fasting. In obese hypertensives, plasma atrial natriuretic peptide (ANP) levels were found to be lower than in obese normotensives. Therefore, the increased adipose mass might influence ANP levels and/or its biological activity. The aim of the present study was to evaluate whether the humoral, hemodynamic, and renal effects of exogenous ANP in obese hypertensives might be enhanced by a very low calorie diet. Eight obese hypertensives received a bolus injection of ANP (0.6 mg/kg) after 2 weeks of a normal calorie/normal sodium diet, and blood pressure (BP), heart rate, ANP, cGMP, plasma renin activity, and aldosterone were evaluated for 2 hours before and after the injection. Diuresis and natriuresis were measured every 30 minutes. The patients then started a low calorie/normal sodium diet (510 kcal/150 mmol/d) for 4 days, and then the ANP injection protocol was repeated. The low calorie diet induced a slight weight loss (from 90.6+/-1.1 to 87. 7+/-1.2 kg; P<0.01), which was accompanied by increase of cGMP excretion (from 146.0+/-10.1 to 154.5+/-9.5 nmol/24 h; P<0.05) together with a reduction of BP (P<0.01 versus basal levels). ANP injection after diet was followed by an increase of ANP levels similar to that observed before diet, but plasma cGMP, diuresis, and natriuresis increased significantly only after diet. Similarly, the decrease of BP after ANP administration was significantly higher after diet (change in mean arterial pressure, -6.4+/-0.7 versus -4. 0+/-0.6 mm Hg; P<0.05) as well as that of aldosterone (P<0.01). These data show that a low calorie diet enhances the humoral, renal, and hemodynamic effects of ANP in obese hypertensives and confirm the importance of caloric intake in modulating the biological activity of ANP, suggesting that the natriuretic peptide system can play a role in the acute changes of natriuresis and diuresis associated with caloric restriction.