USE OF THE POROUS BALLOON IN PORCINE CORONARY-ARTERIES - RATIONALE FOR LOW-PRESSURE AND VOLUME DELIVERY

Using agents administered systemically, attempts to control the resten otic myoproliferative response associated with angioplasty have been u nsuccessful. The porous balloon has the advantage of achieving high lo cal concentrations by directly infusing agents into the arterial wall. The purpose of this study is to identify any acute and chronic morpho logical changes in swine coronary arteries infused with normal saline through the porous balloon at different driving pressures. In order to establish the safety of local arterial wall infusion through the poro us balloon, swine underwent porous balloon infusion of 3, 6, or 10 ml of saline at 5 atmospheres, or infusion of 3 ml of normal saline deliv ered at either 2, 5, or 10 atmospheres of pressure into the normal lef t anterior descending and left circumflex arteries. To assess the hist opathologic alterations induced by the porous balloon, sized 1.1 to 1 with respect to the artery, animals were sacrificed either immediately after porous balloon infusion or 14 days later. Acute vessels were ev aluated for the presence of medial injury, disruption and/or dissectio n, whereas chronic vessels underwent morphometric analysis measuring t he residual luminal area (Lumen area/lntimal area + Lumen area) and th e maximal intimal thickness. Adequate adventitial penetration was conf irmed by infusing as little as 2-3 mi of methylene blue at 2 atmospher es of pressure. Infusion of 3 mi of normal saline at 2 atmospheres res ulted in minor focal medial edema and disorganization, detected both a cutely and 14 days after porous balloon infusion. At delivery pressure s of 5 or 10 atmospheres, proportionally more acute injury was noted a nd measurable neointimal lesions were observed 2 weeks after infusion. These data indicate that porous balloon infusion of 3 ml of normal sa line at 2 atmospheres was safe and resulted in only minimal medial ede ma of normal swine coronary arteries. Higher pressure or volume delive ry proportionally increased the degree of injury and contributed to th e development of neointima. (c) 1993 Wiley-Liss, Inc.