The effect of dissolved carbon dioxide on cavitation intensity in mechanical heart valves

Luke H Herbertson, Keefe B Manning, Varun Reddy, Arnold A Fontaine, John M Tarbell, Steven Deutsch
Journal of Heart Valve Disease 2005, 14 (6): 835-42

BACKGROUND AND AIM OF THE STUDY: Mechanical heart valves (MHVs) are known to induce cavitation during closure and rebound. Cavitation may lead to blood element damage and stable bubble formation, with the latter introducing emboli into the cranial circulation and increasing the risk of stroke. Previous research has suggested that CO2 is the primary blood gas involved in stable bubble growth, due to its high solubility compared to that of oxygen or nitrogen. The primary objective of this study is to determine the role that CO2 plays in MHV-induced cavitation bubble formation.

METHODS: Degassed water (5 ppm) was supplemented with CO2 at partial pressures of 0, 40 and 100 mmHg. Cavitation was visualized using high-speed videography for 29 mm Björk-Shiley Monostrut and Medtronic Hall MHVs in the mitral position. Experimental parameters (heart rate, systolic duration, and left ventricular pressure) were adjusted to provide dp/dt values of 500, 2,500 and 4,500 mmHg/s. High-frequency pressure fluctuations of cavitation bubble collapse were detected using a hydrophone.

RESULTS: Root-mean square (RMS) values were calculated to quantify the cavitation intensity for both MHVs at the three loading conditions. The images of cavitation bubble formation and collapse were correlated to their respective RMS values. This study revealed no statistical difference between the cavitation intensities produced by either of the MHVs for the range of CO2-supplemented degassed water tested. For example, at the most physiologic loading condition of 2,500 mmHg/s, the RMS values for the Björk-Shiley Monostrut valve in degassed water containing 0 and 100 mmHg CO2 were 32.7 +/- 3.5 and 34.3 +/- 6.1 mmHg, respectively.

CONCLUSION: The results of this in-vitro study show that, despite affecting stable bubble growth, the presence and quantity of dissolved CO2 does not affect the intensity of the cavitation events occurring during impact of the valve occluder with its housing. Therefore, the role of CO2 is limited to stable bubble development.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"