Carotid artery vasoreactivity correlates with abdominal aortic vasoreactivity in young healthy individuals but not in patients with abdominal aortic aneurysm.

Background: Sympathetic stimulation of central arteries, such as coronary and carotid arteries, cause vasodilation in healthy subjects, but vasoconstriction in those with increased cardiovascular risk. This study compared vasoreactivity to sympathetic stimulation between abdominal aorta and carotid artery in healthy young individuals (young group, n = 20), in patients with abdominal aortic aneurysm (AAA group, n = 20) and in a healthy older group, age- and gender matched with AAA group (matched group, n = 18). Method: All subjects underwent cold pressor test, while performing concomitantly duplex ultrasound of abdominal aorta and carotid artery vasoreactivity. Observer-independent software was used to analyze and calculate magnitude and timing of maximum vasodilation or vasoconstriction. Pearson's correlation coefficient was calculated to investigate vasoreactivity between arteries. Results: Carotid artery reactivity [Interquartile range 25%, Interquartile range 75%] did not significantly differ between the young, matched and AAA group (3.5% [1.4, 4.7], 2.6% [2.0, 4.1] and 2.2% [-1.9, 3.7], respectively, p = 0.301). Abdominal aortic responsiveness demonstrated larger differences between young (4.9% [-0.2, 8.4]), matched (3.3% [-2.5, 4.4]) and individuals with AAA (0.5% [-3.9, 4.1], p = 0.059). Pooled analysis showed a significant correlation between carotid and abdominal aortic vasoreactivity (r = 0.444, p = 0.001). Subgroup analyses demonstrated significant correlation between both arteries in young (r = 0.636, p = 0.003), but not matched (r = −0.040, p = 0.866) or AAA group (r = 0.410, p = 0.129). Conclusions: Sympathetic stimulation induces powerful vasodilation of the carotid artery and abdominal aorta, which is significantly correlated in healthy individuals. No such correlation is present in abdominal aortic aneurysm patients. This suggests the aneurysm alters local abdominal aorta vasoreactivity, but not the carotid artery

CYP2C19 genotype-guided antithrombotic treatment versus conventional clopidogrel therapy in peripheral arterial disease: study design of a randomized controlled trial (GENPAD)

BACKGROUND: Clopidogrel is recommended in international guidelines to prevent arterial thrombotic events in patients with peripheral arterial disease (PAD). Clopidogrel itself is inactive and metabolism is dependent on the CYP2C19 enzyme. About 30% of Caucasian PAD patients receiving clopidogrel carry 1 or 2 CYP2C19 loss-of-function allele(s) and do not or to a limited extent convert the prodrug into its active metabolite. As a result, platelet inhibition may be inadequate which could lead to an increased risk of adverse clinical events related to arterial thrombosis. A CYP2C19 genotype-guided antithrombotic treatment might be beneficial for PAD patients. METHODS: GENPAD is a multicenter randomized controlled trial involving 2,276 PAD patients with an indication for clopidogrel monotherapy. Patients with a separate indication for dual antiplatelet therapy or stronger antithrombotic therapy are not eligible for study participation. Patients randomized to the control group will receive clopidogrel 75 mg once daily without pharmacogenetic guidance. Patients randomized to the intervention group will be tested for carriage of CYP2C19 *2 and *3 loss-of-function alleles, followed by a genotype-guided antithrombotic treatment with either clopidogrel 75 mg once daily for normal metabolizers, clopidogrel 150 mg once daily for intermediate metabolizers, or acetylsalicylic acid 80 mg once daily plus rivaroxaban 2.5 mg twice daily for poor metabolizers. The primary outcome is a composite of myocardial infarction, ischemic stroke, cardiovascular death, acute or chronic limb ischemia, peripheral vascular interventions, or death. The secondary outcomes are the individual elements of the primary composite outcome and clinically relevant bleeding complications. CONCLUSION: The aim of the GENPAD study is to evaluate the efficacy, safety, and cost-effectiveness of a genotype-guided antithrombotic treatment strategy compared to conventional clopidogrel treatment in PAD patients

Dual pathway inhibition as compared to acetylsalicylic acid monotherapy in relation to endothelial function in peripheral artery disease, a phase IV clinical trial

Objective: Dual pathway inhibition (DPI) by combining acetylsalicylic acid (ASA) with low-dose rivaroxaban has been shown to reduce cardiovascular events in patients with peripheral arterial disease (PAD) when compared to ASA monotherapy. A potential explanation is that inhibition of factor Xa improves endothelial function through crosstalk between coagulation and inflammatory pathways, subsequently attenuating the occurrence of cardiovascular events. We hypothesize that the addition of rivaroxaban to ASA in PAD patients leads to improved endothelial function. Design: An investigator-initiated, multicentre trial investigating the effect of DPI on endothelial function. Methods: Patients, diagnosed with PAD, were enrolled in two cohorts: cohort A (Rutherford I-III) and cohort B (Rutherford IV-VI). Participants received ASA monotherapy for a 4-weeks run-in period, followed by 12 weeks of DPI. Macro- and microvascular endothelial dysfunction were studied by measuring carotid artery reactivity upon sympathetic stimulus and by measuring plasma endothelin-1 concentrations, respectively. All measurements were performed during the use of ASA (baseline) and after 12 weeks of DPI. Results: 159 PAD patients (111 cohort A, 48 cohort B) were enrolled. Twenty patients discontinued study drugs early. Carotid artery constriction upon sympathetic stimulation at baseline (ASA) and after 12 weeks of DPI was similar in the total group, 22.0 vs. 22.7% (p = 1.000), and in the subgroups (Cohort A 22.6 vs. 23.7%, p = 1.000; cohort B 20.5 vs. 20.5%, p = 1.000), respectively. The mean concentration of plasma endothelin-1 at baseline and after 12 weeks of DPI did not differ, 1.70 ± 0.5 vs. 1.66 ± 0.64 pmol/L (p = 0.440) in the total group, 1.69 ± 0.59 vs. 1.62 ± 0.55 pmol/L in cohort A (p = 0.202), and 1.73 ± 0.53 vs. 1.77 ± 0.82 pmol/L in cohort B (p = 0.682), respectively. Conclusion: Macro- and microvascular endothelial dysfunction, as reflected by carotid artery reactivity and plasma endothelin-1 concentrations, are not influenced in PAD patients by addition of low-dose rivaroxaban to ASA monotherapy for 12 weeks. Trial registration: https://clinicaltrials.gov/ct2/show/NCT04218656

A systematic review summarizing local vascular characteristics of the aneurysm wall to predict progression and rupture risk of abdominal aortic aneurysms.

Objective: Rupture risk prediction of abdominal aortic aneurysms (AAA), and hence clinical decision making on the need for surgery, is currently based on AAA diameter and growth rate. Unfortunately, these measures provide limited predictive information. This study summarized measures of local vascular characteristics of the aneurysm wall that, independent of AAA size, could predict AAA progression and AAA rupture. Method: Pubmed and Web of Science were systematically searched up to September 13th, 2021 to identify relevant articles investigating the relationship between local vascular characteristics of the aneurysm wall and AAA growth or rupture in humans. Quality assessment was performed with the ROBINS-I tool. All included articles were divided in four types of measure of arterial wall characteristics; metabolism, calcification, intraluminal thrombus and compliance. Results: Twenty articles were included. Metabolism of the aneurysm wall, especially measured with ultra-small superparamagnetic iron oxide uptake, and calcification were significantly related to AAA growth. Higher intraluminal thrombus volume and thickness was in one study positively correlated to AAA growth and in another study negatively correlated. AAA compliance demonstrated no correlation with AAA growth and rupture. Aneurysmal wall characteristics showed no association with AAA rupture. However, metabolism measured by ultra-small superparamagnetic iron oxide uptake, but none of the other measures, showed a trend toward a relation to AAA rupture, although not statistically significant. Conclusion: Current measures of aortic wall characteristics have potential to predict AAA growth, especially measuring metabolism and calcification. Evidence regarding AAA rupture is scarce and although more work is needed, aortic wall metabolism could potentially be related to AAA rupture. This highlights the role of aortic wall characteristics in the progression of AAA, but also the potential to improve prediction of AAA growth and rupture

Experience with the GORE EXCLUDER iliac branch endoprosthesis for common iliac artery aneurysms

Objective: In this study, we analyzed the procedural success and early outcome of endovascular treatment of a multicenter cohort of patients with common iliac artery (CIA) aneurysms treated with the new GORE EXCLUDER (W. L. Gore & Associates, Flagstaff, Ariz) iliac branch endoprosthesis (IBE). Methods: A retrospective cohort analysis was performed in 13 sites in The Netherlands. Anatomic, demographic, procedural, and follow-up data were assessed from hospital records. Results: From November 2013 to December 2014, 51 CIA aneurysms were treated with an IBE in 46 patients. The median diameter of the treated aneurysm was 40.5 (range, 25.0-90.0) mm. The mean procedural time was 198 +/- 56 minutes. All but one implantation were successful; two type Ib endoleaks were noticed, resulting in a procedural success rate of 93.5%. The two type Ib endoleaks spontaneously disappeared at 30 days. There was no 30-day mortality. Ipsilateral buttock claudication was present in only two cases at 30 days and disappeared during follow-up. The incidence of reported erectile dysfunction was low and severe ischemic complications were absent. After a mean follow-up of 6 months, data on 17 treated aneurysms were available. Two showed a stable diameter, whereas 15 showed a mean decrease of 3.9 +/- 2.2 mm (P < .001). Reinterventions were performed in two patients (7.1%). The 6-month primary patency of the internal component of the IBE device was 94%. Conclusions: The use of the GORE EXCLUDER IBE device for CIA aneurysms is related to high procedural success, high patency rates, and low reintervention rates at short-term follow-up. Prospective data with longer follow-up are awaited to establish the role of the device in the treatment algorithm of CIA aneurysms