Pulse wave velocity correlates with aortic atherosclerosis assessed with transesophageal echocardiography

Restoration of flow in the aorta: a novel therapeutic target in aortic valve intervention

Aortic blood flow patterns are closely linked to the morphology and function of the left ventricle, aortic valve and aorta. These flow patterns demonstrate the exceptional adaptability of the cardiovascular system to maintain blood circulation under a broad range of haemodynamic workloads and can be altered in various pathophysiological states. For instance, normal ascending aortic systolic flow is predominantly laminar, whereas abnormal aortic systolic flow is associated with increased eccentricity, vorticity and flow reversal. These flow abnormalities result in reduced aortic conduit function and increased energy loss in the cardiovascular system. Emerging evidence details the association of these flow patterns with loss of aortic compliance, which leads to adverse left ventricular remodelling, poor tissue perfusion, and an increased risk of morbidity and death. In this Perspective article, we review the evidence for the link between aortic flow-related abnormalities and cardiovascular disease and how these changes in aortic flow patterns are emerging as a therapeutic target for aortic valve intervention in first-in-human studies.

The role of oxygen transport in atherosclerosis and vascular disease

Atherosclerosis and vascular disease of larger arteries are often associated with hypoxia within the layers of the vascular wall. In this review, we begin with a brief overview of the molecular changes in vascular cells associated with hypoxia and then emphasize the transport mechanisms that bring oxygen to cells within the vascular wall. We focus on fluid mechanical factors that control oxygen transport from lumenal blood flow to the intima and inner media layers of the artery, and solid mechanical factors that influence oxygen transport to the adventitia and outer media via the wall's microvascular system-the vasa vasorum (VV). Many cardiovascular risk factors are associated with VV compression that reduces VV perfusion and oxygenation. Dysfunctional VV neovascularization in response to hypoxia contributes to plaque inflammation and growth. Disturbed blood flow in vascular bifurcations and curvatures leads to reduced oxygen transport from blood to the inner layers of the wall and contributes to the development of atherosclerotic plaques in these regions. Recent studies have shown that hypoxia-inducible factor-1α (HIF-1α), a critical transcription factor associated with hypoxia, is also activated in disturbed flow by a mechanism that is independent of hypoxia. A final section of the review emphasizes hypoxia in vascular stenting that is used to enlarge vessels occluded by plaques. Stenting can compress the VV leading to hypoxia and associated intimal hyperplasia. To enhance oxygen transport during stenting, new stent designs with helical centrelines have been developed to increase blood phase oxygen transport rates and reduce intimal hyperplasia. Further study of the mechanisms controlling hypoxia in the artery wall may contribute to the development of therapeutic strategies for vascular diseases.

Underlying embolic and pathologic differentiation by cerebral microbleeds in cryptogenic stroke

BACKGROUND

Cryptogenic stroke encompasses diverse emboligenic mechanisms and pathogeneses. Cerebral microbleeds (CMBs) occur differently among stroke subtypes. The association of CMBs with cryptogenic stroke is essentially unknown.

METHODS

CHALLENGE ESUS/CS (Mechanisms of Embolic Stroke Clarified by Transesophageal Echocardiography for ESUS/CS) is a multicenter registry with comprehensive data including gradient-echo T2*-weighted magnetic resonance imaging of cryptogenic stroke patients who underwent transesophageal echocardiography. Patients' clinical characteristics were compared according to the presence and location of CMBs.

RESULTS

A total of 661 patients (68.7 ± 12.7 years; 445 males) were enrolled, and 209 (32%) had CMBs. Age (odds ratio [OR] 1.02, 95% confidence interval [CI] 1.00-1.04, p = 0.020), male sex (OR 1.85, 95% CI 1.18-2.91, p = 0.007), hypertension (OR 1.71, 95% CI 1.03-2.86, p = 0.039), chronic kidney disease (OR 1.64, 95% CI 1.11-2.43, p = 0.013), deep and subcortical white matter hyperintensity (OR 1.82, 95% CI 1.16-2.85, p = 0.009), and periventricular hyperintensity (OR 2.18, 95% CI 1.37-3.46, p = 0.001) were independently associated with the presence of CMBs. Aortic complicated lesions (OR 1.78, 95% CI 1.12-2.84, p = 0.015) were associated with deep and diffuse CMBs, whereas prior anticoagulant therapy (OR 7.88, 95% CI, 1.83-33.9, p = 0.006) was related to lobar CMBs.

CONCLUSIONS

CMBs were common, and age, male sex, hypertension, chronic kidney disease, and cerebral white matter diseases were related to CMBs in cryptogenic stroke. Aortic complicated lesions were associated with deep and diffuse CMBs, while prior anticoagulant therapy was related to lobar CMBs.

Association between Aortic Atheroma and Cerebral Small Vessel Disease in Patients with Ischemic Stroke

BACKGROUND AND PURPOSE

Cerebral small vessel disease (SVDs) are related with large artery atherosclerosis. However, the association between aortic atheroma (AA) and cerebral small vessel disease has rarely been reported. This study evaluated the relationship between presence and burden of AAs and those of SVDs in patients with acute ischemic stroke.

METHODS

We included 737 consecutive patients who underwent transesophageal echocardiography (TEE) and brain magnetic resonance imaging (MRI) for evaluation of acute stroke. AA subtypes were classified as complex aortic plaque (CAP) and simple aortic plaque (SAP). Presence and burden of SVDs including cerebral microbleeds (CMBs), white matter hyperintensities (WMHs), perivascular spaces (PVSs), asymptomatic lacunar infarctions (ALIs), and total SVD score, were investigated.

RESULTS

AA was found by TEE in 360 (48.8%) patients including 11.6% with CAP and 37.2% with SAP. One or more types of SVDs was found in 269 (36.4%) patients. In multivariable analysis, presence of CMBs (odds ratio [OR] 4.68), high-grade WMHs (OR 3.13), high-grade PVSs (OR 3.35), and ALIs (OR 4.24) were frequent in patients with AA than those without AA. Each 1-point increase in total SVD score increased the odds of presence of CAP (OR 1.94, 95% confidence interval (CI) 1.44-1.85) and SAP (OR 1.54, 95% CI 1.35-1.75).

CONCLUSIONS

In this study, patients with AA frequently had cerebral SVDs. Larger burden of AA was associated with advanced cerebral SVDs. Our findings give an additional information for positive relationship with systemic atherosclerosis and coexisting cerebral SVDs in acute ischemic stroke patients.