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Hemodynamic significance of the coronary vein valves
Pan-Chih1, A H Huang, L M Dorsey
1Carlyle Fraser Heart Center, Crawford Long Hospital, Emory University, Atlanta, GA 30365.
Insights
Competent one-way valves in coronary veins, particularly in younger humans and calves, can impede retrograde cardioplegia delivery. These valves require specific pressure gradients to open, potentially affecting cardiac surgery outcomes.
Area of Science:
- Cardiovascular Anatomy
- Surgical Physiology
Background:
- One-way valves exist in coronary veins, potentially influencing fluid dynamics.
- Understanding these valves is crucial for optimizing retrograde cardioplegia delivery during cardiac procedures.
Purpose of the Study:
- To investigate the incidence and morphology of coronary vein valves.
- To assess the impact of these valves on retrograde cardioplegia administration.
Main Methods:
- Dissection of calf, pig, canine, and human cadaver hearts.
- Measurement of pressure gradients across coronary sinus and posterior left ventricular vein.
- Retrograde fluid administration to assess valve function.
Main Results:
- Species-specific differences in valve frequency: more in calves and pediatric humans than pigs and adult humans.
- No competent valves found in canine hearts.
- Opening pressure gradients varied by species (e.g., 5-35.5 mm Hg in calves, 0-19.5 mm Hg in pigs).
Conclusions:
- Competent coronary vein valves can impair retrograde cardioplegia distribution.
- Valve function is dependent on pressure gradients, with implications for surgical technique.
- Further research may refine cardioplegia delivery strategies based on valve presence.
Abstract:
The incidence and morphology of one-way coronary vein valves were studied, together with their influence on the administration of retrograde cardioplegia. Calf, juvenile pig, and adult mongrel canine hearts (12 each) and human cadaver hearts (five adult and seven pediatric) were dissected. The pressure gradients between the coronary sinus and the posterior vein of the left ventricle were measured in 21 hearts during the retrograde administration of fluid. Species differences were noted, with apparently competent valves seen more frequently in calf hearts (mean, 1.33 valves +/- 0.22 [SEM] per heart) than in pig hearts (mean, 0.83 +/- 0.17 [SEM] per heart). In humans, more valves were seen in pediatric hearts (five valves in seven hearts) than in adult hearts (one valve in five hearts). No competent valves were found in dog hearts (chi 2 analysis; p < 0.0001). In calf hearts, a pressure gradient of 5 to 35.5 mm Hg was required before the valve opened. In pig hearts, these opening pressure gradients ranged from 0 to 19.5 mm Hg. The distribution of retrograde cardioplegia may be impaired in the presence of competent valves, particularly when low coronary sinus pressures are used.