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Low frequency mechanical actuation accelerates reperfusion in-vitro.

Marzencki M, Kajbafzadeh B, Khosrow-Khavar F, Tavakolian K, Soleimani-Nouri M, Hamburger J, Kaminska B, Menon C - Biomed Eng Online (2013)

Bottom Line: Alternative or adjunctive emergency therapies that could be initiated by minimally trained personnel in the field are of potential clinical benefit.We consider a stenosed, heparinized flow system with aortic-like pressure variations subject to direct vessel vibration at the occlusion site or vessel deformation proximal and distal to the occlusion site, versus a reference system lacking any form of mechanical stimulus on the vessels.For vessel deformation at occlusion site 95% of clots perfused within 11 minutes of application of mechanical stimulus, for vessel deformation 60 centimeters from the occlusion site 95% percent of clots perfused within 16 minutes of stimulus application, while only 2.3% of clots perfused within 20 minutes in the reference system.

View Article: PubMed Central - HTML - PubMed

Affiliation: 1Faculty of Appliced Science, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada. cmenon@sfu.ca.

ABSTRACT

Background: Rapid restoration of vessel patency after acute myocardial infarction is key to reducing myocardial muscle death and increases survival rates. Standard therapies include thrombolysis and direct PTCA. Alternative or adjunctive emergency therapies that could be initiated by minimally trained personnel in the field are of potential clinical benefit. This paper evaluates a method of accelerating reperfusion through application of low frequency mechanical stimulus to the blood carrying vessels.

Materials and method: We consider a stenosed, heparinized flow system with aortic-like pressure variations subject to direct vessel vibration at the occlusion site or vessel deformation proximal and distal to the occlusion site, versus a reference system lacking any form of mechanical stimulus on the vessels.

Results: The experimental results show limited effectiveness of the direct mechanical vibration method and a drastic increase in the patency rate when vessel deformation is induced. For vessel deformation at occlusion site 95% of clots perfused within 11 minutes of application of mechanical stimulus, for vessel deformation 60 centimeters from the occlusion site 95% percent of clots perfused within 16 minutes of stimulus application, while only 2.3% of clots perfused within 20 minutes in the reference system.

Conclusion: The presented in-vitro results suggest that low frequency mechanical actuation applied during the pre-hospitalization phase in patients with acute myocardial infarction have potential of being a simple and efficient adjunct therapy.

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Related in: MedlinePlus

Histogram of initial clot masses for setup A. Distribution of clot masses prior to the experiments using the setup A.
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Figure 10: Histogram of initial clot masses for setup A. Distribution of clot masses prior to the experiments using the setup A.

Mentions: Whole blood was collected from the left jugular vein of a sheep (female, Ovis aries, Suffolk breed) elevated in a controlled environment at UBC Farm. Blood was drawn under standardized conditions into a 60 ml syringe and immediately distributed into sterile silicon tubing (ID 4.76 mm), sealed inside a double zip-lock bag and placed into a water bath held at 37°C. Ninety minutes from blood extraction, the clotted blood was removed from the bath and inspected visually for retraction. The retracted clot was pressed out of the silicon tube and verified for uniformity. The long columnar clot was then cut into 15 mm pieces and each piece was weighted separately using a digital scale (VB-302A, Virtual Measurements & Control, Santa Rosa, CA). The resulting distribution of clot weights in each experiment is detailed in Figures 10, 11 and 12. Cut and weighted clots were immediately inserted into the flow system by disconnecting the narrowings separately one by one at clamping, placing a clot inside the tube with a spatula and subsequently flooding it with the fluid from the beaker and reconnecting the narrowing. Upon re-pressurization the clots occluded the closest stenosis site. Special care was taken to remove all air bubbles from the system prior to pressurizing and not to damage the clots mechanically. The clot distribution between the stenosed channels and the reference versus the actuated setups was randomized.


Low frequency mechanical actuation accelerates reperfusion in-vitro.

Marzencki M, Kajbafzadeh B, Khosrow-Khavar F, Tavakolian K, Soleimani-Nouri M, Hamburger J, Kaminska B, Menon C - Biomed Eng Online (2013)

Histogram of initial clot masses for setup A. Distribution of clot masses prior to the experiments using the setup A.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4222658&req=5

Figure 10: Histogram of initial clot masses for setup A. Distribution of clot masses prior to the experiments using the setup A.
Mentions: Whole blood was collected from the left jugular vein of a sheep (female, Ovis aries, Suffolk breed) elevated in a controlled environment at UBC Farm. Blood was drawn under standardized conditions into a 60 ml syringe and immediately distributed into sterile silicon tubing (ID 4.76 mm), sealed inside a double zip-lock bag and placed into a water bath held at 37°C. Ninety minutes from blood extraction, the clotted blood was removed from the bath and inspected visually for retraction. The retracted clot was pressed out of the silicon tube and verified for uniformity. The long columnar clot was then cut into 15 mm pieces and each piece was weighted separately using a digital scale (VB-302A, Virtual Measurements & Control, Santa Rosa, CA). The resulting distribution of clot weights in each experiment is detailed in Figures 10, 11 and 12. Cut and weighted clots were immediately inserted into the flow system by disconnecting the narrowings separately one by one at clamping, placing a clot inside the tube with a spatula and subsequently flooding it with the fluid from the beaker and reconnecting the narrowing. Upon re-pressurization the clots occluded the closest stenosis site. Special care was taken to remove all air bubbles from the system prior to pressurizing and not to damage the clots mechanically. The clot distribution between the stenosed channels and the reference versus the actuated setups was randomized.

Bottom Line: Alternative or adjunctive emergency therapies that could be initiated by minimally trained personnel in the field are of potential clinical benefit.We consider a stenosed, heparinized flow system with aortic-like pressure variations subject to direct vessel vibration at the occlusion site or vessel deformation proximal and distal to the occlusion site, versus a reference system lacking any form of mechanical stimulus on the vessels.For vessel deformation at occlusion site 95% of clots perfused within 11 minutes of application of mechanical stimulus, for vessel deformation 60 centimeters from the occlusion site 95% percent of clots perfused within 16 minutes of stimulus application, while only 2.3% of clots perfused within 20 minutes in the reference system.

View Article: PubMed Central - HTML - PubMed

Affiliation: 1Faculty of Appliced Science, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada. cmenon@sfu.ca.

ABSTRACT

Background: Rapid restoration of vessel patency after acute myocardial infarction is key to reducing myocardial muscle death and increases survival rates. Standard therapies include thrombolysis and direct PTCA. Alternative or adjunctive emergency therapies that could be initiated by minimally trained personnel in the field are of potential clinical benefit. This paper evaluates a method of accelerating reperfusion through application of low frequency mechanical stimulus to the blood carrying vessels.

Materials and method: We consider a stenosed, heparinized flow system with aortic-like pressure variations subject to direct vessel vibration at the occlusion site or vessel deformation proximal and distal to the occlusion site, versus a reference system lacking any form of mechanical stimulus on the vessels.

Results: The experimental results show limited effectiveness of the direct mechanical vibration method and a drastic increase in the patency rate when vessel deformation is induced. For vessel deformation at occlusion site 95% of clots perfused within 11 minutes of application of mechanical stimulus, for vessel deformation 60 centimeters from the occlusion site 95% percent of clots perfused within 16 minutes of stimulus application, while only 2.3% of clots perfused within 20 minutes in the reference system.

Conclusion: The presented in-vitro results suggest that low frequency mechanical actuation applied during the pre-hospitalization phase in patients with acute myocardial infarction have potential of being a simple and efficient adjunct therapy.

Show MeSH
Related in: MedlinePlus