title: Reduction of arterial graft smooth muscle mass by moderate heat therapy.
abstract: Radial artery (RA) graft spasm is a major cause of early graft failure in coronary artery bypass grafting surgeries. We explored the feasibility of thermal reduction of smooth muscle mass to attenuate vasoconstriction. Rat and rabbit femoral arteries were treated thermally in situ (45°C to 65°C; 0 s to 120 s) and then excised at various time points for histological and physiological study (pressure-diameter relationships). Human radial arteries were treated in vitro and studied in similar fashion. Weeks after thermal treatment, no overt indication was noted of vasospasm, thrombosis, or scarring in the arterial wall; however, this intervention led to a thermal dose-dependent reduction of vasoconstriction (to phenylephrine or potassium chloride) and to a conspicuous loss of smooth muscle. Pressure-diameter relationships showed no aneurismal dilation of these demuscularized arteries up to 200 mmHg. Qualitatively identical results were obtained in human radial arteries. Thermal ablation of RAs may provide a simple, safe, and effective solution to postsurgical vasospasm.
authors.affiliation: Firestone Institute for Respiratory Health, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Irem
authors.initials: I
authors.lastname: Mueed
authors.forename: Tracy
authors.initials: T
authors.lastname: Tazzeo
authors.forename: Lindsay
authors.initials: L
authors.lastname: Doharris
authors.forename: Tariq
authors.initials: T
authors.lastname: Aziz
authors.forename: Victor
authors.initials: V
authors.lastname: Chu
authors.forename: Luke J
authors.initials: LJ
authors.lastname: Janssen
mesh_terms: D000368:Aged; D000818:Animals; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000379:methods; D003329:Coronary Vasospasm / Q000517:prevention & control; D005263:Femoral Artery / Q000033:anatomy & histology* / Q000502:physiology* / Q000637:transplantation; D006358:Hot Temperature / Q000627:therapeutic use*; D006801:Humans; D066298:In Vitro Techniques; D008875:Middle Aged; D023421:Models, Animal; D009131:Muscle, Smooth, Vascular / Q000033:anatomy & histology* / Q000502:physiology*; D010477:Perfusion; D011183:Postoperative Complications / Q000517:prevention & control; D011817:Rabbits; D017534:Radial Artery / Q000033:anatomy & histology / Q000502:physiology / Q000637:transplantation; D000078702:Radiofrequency Therapy; D051381:Rats; D014654:Vascular Patency; D014661:Vasoconstriction