Center-To-Periphery Arterial Stiffness Gradient Is Attenuated and/or Reversed in Pregnancy-Associated Hypertension

Background: Non-pregnant (NP) women have a progressive increase in arterial stiffness from central-to-peripheral arteries [“stiffness gradient” (SG)], which is of physiologic importance since excessive pulsatility is filtered by the creation of wave reflections. If the aorta gets stiff with minimal or no change in the periphery, the SG is dissipated transmitting pressure disturbances to the microcirculation. It remains unknown the status of the SG in both women with healthy pregnancies (HP) and complicated by pregnancy-associated hypertension (PAH).Objective: To determine whether HP and PAH are associated with changes in SG. Secondarily, we aim at identifying potential differences between the subgroups of PAH (pre-eclampsia and gestational hypertension).Methods: HP (n = 10), PAH (n = 16), and healthy NP women (n = 401, to be matched for age, and cardiovascular risk with the pregnant women) were included. Carotid-to-femoral (cfPWV) and carotid-to-radial pulse wave velocity (crPWV), common carotid artery (CCA) and brachial artery (BA) diameters and elastic modulus (EM), and regional (cfPWV/crPWV or “PWV ratio”) and local (CCA EM/BA EM or “EM ratio”) SG were quantified.Results: HP showed no changes in PWV ratio compared with NP, in the presence of significantly lower cfPWV and crPWV. HP exhibited higher arterial diameters and lower CCA EM/BA EM compared to NP, without differences with PAH. PAH was associated with a significant increase in the PWV ratio that exceeded the levels of both NP and HP, explained by a lower (although significant) reduction of cfPWV with respect to that observed in HP with respect to NP, and a higher reduction in crPWV with respect to that observed between HP and NP. The blunted reduction in cfPWV observed in PAH coincided with an increase in the CCA EM.Conclusions: Compared with NP, HP was associated with unchanged PWV ratio but with a reduction in CCA EM/BA EM, in the setting of a generalized drop in arterial stiffness. Compared with NP and HP, PAH was associated with an “exaggerated rise” in the PWV ratio without changes in CCA EM/BA EM, in the setting of a blunt reduction in cfPWV but exaggerated crPWV drop. The SG attenuation/reversal in PAH was mainly driven by pre-eclampsia.

Comparative study of vasodilatation after intra-arterial nicardipine or dantrolene infusion in animal model of cerebral vasospasm

Intra-arterial (IA) infusions of calcium channel blockers (CCBs) have been widely applied in treating medically refractory vasospasm. However, surprisingly little is known regarding their vasodilatory duration. This study was undertaken to compare attributes of nicardipine and dantrolene, focusing on efficacy and capacity for sustained vasodilation. In New Zealand white rabbits (N=22), vasospasm was individually provoked through experimentally induced subarachnoid hemorrhage and confirmed via conventional angiography, grouping animals by IA-infused drug (nicardipine vs dantrolene). Controls received normal saline. After chemoangioplasty, follow-up angiography was performed at intervals of 1-3 hours for 6 hours to compare vasospastic and dilated (ie, treated) arterial diameters. Drug efficacy, duration of action, and changes in mean arterial pressure (relative to baseline) were analyzed by group. Compared with controls, effective vasodilation was evident in both nicardipine and dantrolene test groups after IA infusion. Vasodilatory effects of nicardipine peaked at 1 hour, returning to former vasospastic states at 3 hours. In dantrolene recipients, vasodilation endured longer, lasting >6 hours. This outcome suggests that IA dantrolene infused alone or together with a conventional CCB infusion may be a new means of prolonging vasodilatory effect. Further research is needed to assess durations of IA-infused vasodilatory drug based on perfusion status.

Calcification Prevalence in Different Vascular Zones and Its Association With Demographics, Risk Factors, and Morphometry

Vascular calcification is associated with a higher incidence of cardiovascular events, but its prevalence in different vascular zones and the influence of demographics, risk factors, and morphometry remain insufficiently understood. Computerized Tomography Angiography scans from 211 subjects 5-93 years old (mean age 47±24 years, 127M/84F) were used to build 3D vascular reconstructions and measure arterial diameters, tortuosity, and calcification volumes in six vascular zones spanning from the ascending thoracic aorta to the pelvic arteries. A machine learning random forest algorithm was used to determine the associations between calcification in each zone with demographics, risk factors, and vascular morphometry. Calcification appeared during the fourth decade of life and was present in all subjects after 65 years. The abdominal aorta and the iliofemoral segment were the first to develop calcification, while the ascending thoracic aorta was the last. Demographics and risk factors explained 33-59% of the variation in calcification. Age, creatinine level, body mass index, coronary artery disease, and hypertension were the strongest contributors, while the effects of gender, race, tobacco use, diabetes, dyslipidemia, and alcohol and substance use disorders on calcification were small. Vascular morphometry did not directly and independently affect calcium burden. Vascular zones develop calcification asynchronously, with distal segments calcifying first. Understanding the influence of demographics and risk factors on calcium prevalence can help better understand the disease pathophysiology and may help with the early identification of patients that are at higher risk of cardiovascular events.

Relationship Between Central Artery Stiffness, Brain Arterial Dilation, and White Matter Hyperintensities in Older Adults: The ARIC Study

Objective: Nonatherosclerotic outward remodeling of the large intracranial arteries may facilitate propagation of excessive aortic pulsatile energy into the cerebral microcirculation and has been associated with adverse cognitive outcomes. We sought to determine the relationship between central artery stiffness, brain arterial diameters, and white matter hyperintensity (WMH) volume in the general population of older adults. Approach and Results: We examined data from 1275 stroke-free participants of the ARIC (Atherosclerosis Risk in Communities) study (59% female, 30% Black, mean age 77 years) who underwent carotid-femoral pulse wave velocity (cf-PWV) testing and brain magnetic resonance imaging. A cf-PWV >12 m/s was considered elevated. Relationships between WMH and arterial diameters at the M1A1 segment of the middle and anterior cerebral arteries (whichever larger) were analyzed in the absence of artery-specific plaque, adjusting for intracranial volume and potential confounders. The average cf-PWV was 11.7 m/s and WMH volume was 11.2 cm 3 . Each 0.5 mm increment in M1A1 diameter was associated with 24% greater WMH volume in participants with elevated cf-PWV (exponentiated β=1.24 [95% CI, 1.12–1.36]), compared with a 10% greater WMH volume in participants without elevated cf-PWV (exponentiated β=1.10 [95% CI, 1.01–1.19]), P value for interaction=0.04. Conclusions: In this examination of older adults from the general population, larger, plaque-free arterial diameters in the middle cerebral circulation were associated with greater WMH volume, particularly among participants with elevated central artery stiffness. Strategies to reduce central artery stiffness may mitigate the association between cerebrovascular outward remodeling and microvascular damage.

VERTEBROBASILAR BLOOD FLOW IN GERIATRIC PATIENTS WITH HIP FRACTURES

Background: Falls constitute a problem especially in individuals aged above 70 years in terms of fracture formation. Considering the etiology of falling, insufficiency of the blood flow which feeds the balance center in the brain may cause postural hypotension and vertigo and may lead to falling. Objective: In this study, we emphasized the importance of evaluating vertebrobasilar blood flow in the etiology of fractures in the elderly. Methods: This study was executed on 48 patients aged 70 years and older (28 females, 20 males, mean age 80.45), who were presented to the emergency department of Dumlupınar University Evliya Çelebi Training and Research Hospital with hip fractures resulting from a simple fall around where they live, diagnosed with hip fractures and treated via joint prostheses or different internal and external fixation methods. After the stabilization of the patients' postoperative fractures, the carotid artery lumen and blood flow, vertebral arterial lumen, diameter and blood flow were examined via doppler ultrasonography. The control group was comprised of 48 patients aged 70 years and older (26 females, 22 males, mean age 75.52 years) who were presented to the Polyclinic of Neurology for routine examination and had no falling and fracture history, and the carotid artery and vertebral artery examination of this group was also performed by the same radiologist via doppler ultrasonography Results: In individuals aged above 70 years, temporary cerebral blood flow disorders are more severe in those with vertebrobasilar insufficiency. This study was conducted between 2015-2016 on 48 patients aged 70 years and older (28 females and 20 males), who were presented to the emergency department of Dumlupınar University Faculty of Medicine Training and Research Hospital and hospitalized due to hip fractures; the control group was comprised of 48 patients within the same age group, who were presented to the Polyclinic of Neurology with different complaints (26 females and 22 males).The vertebral arterial diameters and flow velocities of the patients were assessed via Doppler USG. Conclusion: The vertebral arterial diameters and flow velocities were found statistically lower in the patient group with fracture formation resulting from falling.We recommend taking precautions against the risk of falling in patients aged above 70 years who are found to have a flow decrease through carotid artery doppler USG at certain intervals.