Arvo building, Lecture room F211, address: Arvo Ylpön katu 34.
Doctoral defence of Lic.Med. Antti Tikkakoski
Supine and Upright Hemodynamics Using Non-Invasive Methods : Findings in hypertensive versus normotensive subjects, description of novel functional phenotypes, and effects of nitroglycerin versus salbutamol
The field of science of the dissertation is Internal Medicine.
The opponent is professor Juha Hartikainen (University of Eastern Finland). Professor Ilkka Pörsti acts as the custos.
The language of the dissertation defence is Finnish.
Supine and Upright Hemodynamics Using Non-Invasive Methods
Essential hypertension is a major global health burden, but the primary reason why blood pressure changes in the course of the disease is still in many ways a mystery. Hypertension studies typically measure only blood pressure and heart rate. Normally the measurements of blood pressure are performed in a seated position, which doesn’t reveal anything about the variability or adaptation to normal daily activities.
In study I, the hemodynamics of non-medicated normotensive and hypertensive subjects were studied. Hypertensive subjects had higher systemic vascular resistance and increased arterial stiffness, which correspond with the results from previous studies. In study II, we discovered three new phenotypes, which could only be found by inspecting the changes in hemodynamic variables during passive head-up tilt. The subjects with the constrictor phenotype had the largest increase in systemic vascular resistance and largest decrease in cardiac output. The constrictors had a significantly lower pulse wave velocity, an established marker of arterial stiffness, when compared with subjects in the intermediate and sustainer phenotype. In studies III and IV, inhaled salbutamol was found to have a clearly smaller effect on cardiovascular regulation in the upright than in the supine position. In contrast, the hemodynamic effects of nitroglycerin were accentuated in the upright position. Additionally, the results in studies III and IV established that the change in augmentation index induced by salbutamol inhalation was predominantly correlated with the parallel changes in heart rate and ejection duration.
Our results indicate that the phenotype of primary hypertension is not quantifiable by the mere measurements of supine blood pressure and heart rate. Additionally, not only the level of blood pressure and arterial stiffness, but also the functional phenotype of the cardiovascular system may be associated with cardiovascular risk. A small dose of nitroglycerin has a profound vasodilatory effect that is aggravated in the upright position. In contrast, the moderate effect of salbutamol on hemodynamics is diminished in the upright position, and is connected to the positive chronotropic effect of the compound.
The dissertation is published in the publication series of Acta Universitatis Tamperensis; 2404, Tampere University Press, Tampere 2018. The dissertation is also published in the e-series Acta Electronica Universitatis Tamperensis; 1914, Tampere University Press 2018.