Effect of low grade radiofrequency heating on arterial vasospasm in the porcine model.

Nineteen pigs were studied in order to assess the effect of low grade, radiofrequency-powered, thermal balloon angioplasty on the vasoconstrictor response of peripheral arteries. A mechanical stimulus was used to induce vasospasm. Thermal angioplasty reduced the extent of inducible vasospasm from 79% to 6% compared to nonthermal control inflations, which reduced the vasoconstrictor response from 75% to 60% (P < 0.001). Histologic studies demonstrated that the extent of myocyte necrosis was significantly greater in the thermally treated arteries than in the control vessels (P < 0.01). Thermal balloon angioplasty at 60 degrees C significantly attenuates peripheral arterial vasospasm induced by mechanical trauma in the porcine model. This paralytic effect may be related to the loss of myocytes secondary to thermal necrosis.