Overdrive pacing for endovascular repair of an aortic arch aneurysm.

The endovascular treatment of aortic arch aneurysms is a relatively new technique and is associated with significant surgical and anesthetic challenges. We report a case of a 77-year-old patient with an aortic arch aneurysm at the level of the isthmus, measuring 4.9 x 6.5 cm. The aneurysm involved the origin of the left subclavian and vertebral arteries. The arch was of the bovine type and the left vertebral artery came directly off the aorta. The patient underwent an uneventful open left carotid-to-subclavian bypass several days before the aortic repair. During the endovascular surgery, a stent-graft was deployed just distal to the innominate trunk. Endoleak was noted at the inferior aspect of the stent-graft, which failed to seal with placement of an extension stent-graft. The surgeon then chose to employ a Palmaz stent, to seal the endoleak. Balloon expansion in the ascending aorta was required in order to properly seat the Palmaz stent. Overdrive pacing at a rate of 220 beats min(-1), which lowered the systolic blood pressure (SBP) to 40s mmHg was used during this process after connecting the patient to a Zoll defibrillator with external pads. The Palmaz stent was successfully deployed at the proximal end of the previously deployed stent-graft, using a Tyshak balloon. The patient reverted to normal sinus rhythm with no evidence of ischemia at the conclusion of the overdrive pacing. No endoleak was appreciated after the Palmaz stent was placed.