Effect of Experimental Stenosis on the Vibration of the Porcine Aortic Wall

Objective: To study the vibration adaptation of the aortic wall, after experimentally-induced stenosis in pig descending thoracic aorta. Methods: A 5 mm length, circumferential, rigid, symmetric constriction was created surgically, in eight healthy pigs, producing approximately a 15-20 mmHg pressure drop. Pressure Tip Catheters were used to monitor the pressure drop. Blood flow waveforms were recorded via a Bi-Directional Doppler Flow-meter at pre-A and post-B stenotic areas. Measurements were carried out before, 10 min after and 90 days after the creation of stenosis. The oscillating force acting on the aorta at regions A and B was approximated with the help of blood pressure waveforms. Euthanasia was performed after 90 days and the descending thoracic aorta removed. Eight sham-operated pigs were used as controls. Results: Pressure waveforms were recorded at both A and B sites and maintained until euthanasia. Also, vibration analysis proved that the oscillation frequency of the applied force at A and B regions was greater than that of the control tissues (p<0.05). Conclusions: A minor experimental stenosis located at the level of the descending thoracic aorta increased the oscillating frequency of the vessel. This elevation may act as a "vibration-like disease" to endothelium, to the vasavasorum or even to gene expression of the underlying cells through the developed fatigue or tuning.