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Viagra and Mechanics --- Watermelon May Have Viagra-effect

Mike Ciavarella's picture

I was reading this research from A&M Texas on Viagra and Watermelon. 

http://www.sciencedaily.com/releases/2008/06/080630165707.htm

I have noticed that it has made the front page news on many newspapers
worldwide in a matter of few days.  Maybe we should move to this field,
and because below I find that there are indeed interaction with aorta stiffness and elastic wave reflections.

So if you are interested in a subject of certain high impact, this is a good idea.

Mike


Am J Hypertens (2001) 14, 6A-7A; doi:S0895-7061(01)01335-8
O-18: Sildenafil (Viagra®) improves the elastic properties of the aorta

C. Vlachopoulos1, M. F. O'Rourke1 and K. Hirata1

1St Vincent's Hospital/UNSW, Sydney, NSW, Australia
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Abstract

Sildenafil (S) is a new, effective drug for erectile dysfunction. However, the effect of S on the mechanics of large arteries has not been investigated. Aortic elastic properties are important determinants of left ventricular function and coronary blood flow and have been identified as prognosticators of cardiovascular risk.

To investigate the effect of S on aortic elastic properties we studied 27 pts (age 69plusminus9 years) with risk factors for erectile dysfunction both at baseline (BL) and after oral administration of 50 mg of S, as well as at BL and after placebo. Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic elasticity. PWV (=dL/dt, where dL is the distance travelled by the pulse and dt the time delay between the corresponding foot of pulse waves) was measured using an automated, non-invasive device (Complior®) that has been previously validated.

S led to a decrease in PWV (by 5.2%, fig.) which denotes improvement of aortic elastic properties. This effect was prolonged and lasted throughout the period of measurements (3 hours). This effect was accompanied by a decrease in systolic and diastolic pressure (by 10.7 and 9.1 mmHg respectively; P<0.001 for both).

Sildenafil leads to an improvement of the elastic properties of the aorta. This finding has implications on left ventricular function and coronary blood flow and provides a new insight into the effects of sildenafil on the cardiovascular system.

Consultant - Astra Zeneca, Solvay, Bristol-Myer Squibbs, Pfizer Major Stock Shareholder - PWV Medical Pty. Limited, Sydney, Australia (See Figure)
Keywords:

Pulse Wave Velocity, Aortic Stiffness, Sildenafil

Vascular Medicine, Vol. 8, No. 4, 243-248 (2003)
DOI: 10.1191/1358863x03vm509ra
© 2003 SAGE Publications
Effect of sildenafil on arterial stiffness and wave reflection
Charalambos Vlachopoulos

Medical Professorial Unit, St Vincent’s Hospital and Clinic, University of New South Wales, Sydney, Australia, cvlachop@otenet.gr

Kozo Hirata

Medical Professorial Unit, St Vincent’s Hospital and Clinic, University of New South Wales, Sydney, Australia

Michael F O’Rourke

Medical Professorial Unit, St Vincent’s Hospital and Clinic, University of New South Wales, Sydney, Australia

While sildenafil (Viagra) is widely prescribed for erectile dysfunction, its effect on arterial function is not established. The elastic properties of the aorta, as well as the magnitude and timing of wave reflection, are important factors for efficient performance of the cardiovascular system and have been identified as prognosticators of cardiovascular risk. A total of 24 subjects with coronary artery disease, of whom 14 were hypertensives, aged 69 8 years, were studied in a randomized, placebo-controlled, double-blind, cross-over design. Measurements lasted for 3 h after the sildenafil intake (50 mg, p.o.) or placebo. Aortic elastic properties were evaluated with carotid-femoral pulse wave velocity; wave reflection was evaluated with augmentation index and augmented pressure of the aortic pressure waveform. Pulse wave velocity decreased significantly (by 0.65 m/s, p = 0.005), denoting a decrease in aortic stiffness. Augmentation index and augmented pressure decreased significantly (by 4.47% absolute and by 4.01 mmHg; p < 0.001 and p = 0.001, respectively), denoting a decreased effect of wave reflection from the periphery. Aortic pulse pressure decreased significantly (by 6.74 mmHg, p < 0.05). An active effect of the drug on aortic wall appears to contribute to the decrease in pulse wave velocity, although other mechanisms such as a decrease of blood pressure and autonomic reflexes could also have contributed. The effect of sildenafil lasted throughout the study (3 h), being evident 30 min after drug intake. In conclusion, this study shows, for the first time, that sildenafil has a favorable effect on aortic stiffness and wave reflection in patients with coronary artery disease. This finding may have important implications for cardiovascular performance and exercise capacity during intercourse.

Key Words: aorta • arterial stiffness • arteries • coronary disease • sildenafil

Mechanisms, Pathophysiology, and Therapy of Arterial Stiffness - tutte e 5 le versioni »
SJ Zieman, V Melenovsky, DA Kass - Arteriosclerosis, Thrombosis, and Vascular Biology, 2005 - Am Heart Assoc
Arterial stiffness is a growing epidemic associated with increased risk of
cardiovascular events, dementia, and death. Decreased compliance of the central
vasculature alters arterial pressure and flow dynamics and impacts cardiac .

 

 

 

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