Browsing by Author "Martinez, Gonzalo"

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    Association between spontaneous internal carotid artery dissection and perivascular adipose tissue attenuation on computed tomography angiography
    (2023) Cheng, Kevin; Lin, Andrew; Stecher, Ximena; Bernstein, Tomas; Zuñiga, Paulo; Mazzon, Enrico; Brunse, Alejandro; Diaz, Violeta; Martinez, Gonzalo; Cameron, William; Nicholls, Stephen; Patel, Sanjay; Dey, Damini; Wong, Dennis; Muñoz Venturelli, Paula
    Background: Spontaneous cervical artery dissection (sCAD) is a leading cause of ischemic stroke in young patients. Studies using high-resolution magnetic resonance imaging and positron emission tomography have suggested vessel wall inflammation to be a pathogenic factor in sCAD. Computed tomography (CT) attenuation of perivascular adipose tissue (PVAT) is an established non-invasive imaging biomarker of inflammation in coronary arteries, with higher attenuation values reflecting a greater degree of vascular inflammation. Objectives: We evaluate the CT attenuation of PVAT surrounding the internal carotid artery (PVATcarotid) with and without spontaneous dissection. Methods: Single-centre prospective observational study of 56 consecutive patients with CT-verified spontaneous dissection of the internal carotid artery (ICA) admitted between 2011 and 2018. Of these patients, 6 underwent follow-up CTA. 22 patients who underwent CTA for acute neurological symptoms but did not have dissection formed the control group. Using semiautomated research software, PVATcarotid was measured as the mean Hounsfield Unit (HU) attenuation of adipose tissue within a defined volume of interest surrounding the ICA. Results: PVATcarotid was significantly higher around dissected ICA compared with non-dissected contralateral ICA in the same patients (-58.7±10.2 vs. -68.9±8.1 HU, P<0.0001) and ICA of patients without dissection (-58.7±10.2 vs. -69.3±9.3 HU, P<0.0001). After a median follow-up of 89 days, there was a significant reduction in PVATcarotid around dissected ICA (from -57.5±13.4 to -74.3±10.5 HU, P<0.05); while no change was observed around non-dissected contralateral ICA (from -71.0±4.4 to -74.1±4.1 HU, P=0.19). ICA dissection was an independent predictor of PVATcarotid following multivariable adjustment for age and the presence of ICA occlusion.
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    Heart rate and cardiac autonomic responses to concomitant deep breathing, hand grip exercise, and circulatory occlusion in healthy young adult men and women
    (2021) Andrade, David C.; Melipillan, Claudia; Toledo, Camilo; Rios‑Gallardo, Angélica; Marcus, Noah J.; Ortiz, Fernando C.; Martinez, Gonzalo; Muñoz Venturelli, Paula; Del Rio, Rodrigo
    Background: Deep breathing (DB) and handgrip (HG) exercise -with and without circulatory occlusion (OC) in muscle-, have been shown to have beneficial effects on cardiovascular function; however, the combination of these maneuvers on heart rate (HR) and cardiac sympathovagal balance have not been previously investigated. Therefore, the aim of the present study was to evaluate the effect of simultaneous DB, HG, and OC maneuvers on the sympathovagal balance in healthy women and men subjects. Methods and results: Electrocardiogram and ventilation were measured in 20 healthy subjects (Women: n = 10; age = 27 ± 4 years; weight = 67.1 ± 8.4 kg; and height = 1.6 ± 0.1 m. Men: n = 10; age = 27 ± 3 years; weight = 77.5 ± 10.1 kg; and height = 1.7 ± 0.1 m) at baseline and during DB, DB + HG, or DB + HG + OC protocols. Heart rate (HR) and respiratory rate were continuously recorded, and spectral analysis of heart rate variability (HRV) were calculated to indirectly estimate cardiac autonomic function. Men and women showed similar HR responses to DB, DB + HG and DB + HG + OC. Men exhibited a significant HR decrease following DB + HG + OC protocol which was accompanied by an improvement in cardiac autonomic control evidenced by spectral changes in HRV towards parasympathetic predominance (HRV High frequency: 83.95 ± 1.45 vs. 81.87 ± 1.50 n.u., DB + HG + OC vs. baseline; p < 0.05). In women, there was a marked decrease in HR after completion of both DB + HG and DB + HG + OC tests which was accompanied by a significant increase in cardiac vagal tone (HRV High frequency: 85.29 ± 1.19 vs. 77.93 ± 0.92 n.u., DB + HG vs. baseline; p < 0.05). No adverse effects or discomfort were reported by men or women during experimental procedures. Independent of sex, combination of DB, HG, and OC was tolerable and resulted in decreases in resting HR and elevations in cardiac parasympathetic tone.

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