An evacuation sheath assembly and method of treating occluded vessels which reduces the risk of distal embolization during vascular interventions is provided. A method of treating a lesion within a blood vessel, e.g., a coronary artery, includes advancing a sheath into the blood vessel, the sheath having a lumen extending to a port at a distal end of the sheath and further having an occlusive member within a distal region of the sheath. The occlusive member is then positioned within the blood vessel proximal to the lesion. Subsequently, the occlusive member is deployed, thereby stopping antegrade flow across the lesion. A contrast agent can then be infused through a port in the sheath. A dilation balloon is then advanced across the lesion. Suction is then applied to the lumen to induce retrograde flow across the lesion after dilating the lesion.