extended from the distal arch to the proximal anastomosis of the abdominal aorta. The patient was discharged from our hospital on the twentieth postoperative day.Acute aortic dissection (AAD) during surgery is initially suspected if there is a sudden onset of hypotension or volume loss with unknown cause. Although these signs of dissection were not likely to have been missed, lowered blood pressure, caused by unclamping and subsequent bleeding, may have obscured these signs in our patient. Early detection of intraoperative dissection is important because malperfusion of visceral or cervical branches, extension of the dissection to the ascending aorta, and periaortic hematoma often need additional operation. In AAD type B, medical treatment is currently the preferred method of treatment for patients without complications, and it has a very low mortality rate, of around 1% [3]. However, these patients still have a possibility of developing complications such as those described above. The results of surgery remain suboptimal in the current era, with a reported in-hospital mortality rate of 29.3%. Postoperative complications include cerebrovascular accident, paraplegia, visceral ischemia, acute renal failure, and hypovolemic shock [4]. Tools for diagnosing aortic dissection in the operating room are limited: the visual appearance of the aortic wall, aortography (if fl uoroscopy is available), and echography including TEE. To evaluate aortic dissection, TEE is regarded as a useful tool [5]. We detected, by using TEE, that the proximal extension of the dissection stopped at the distal arch and that the branches of the arch were not involved. The information for diagnosis provided by TEE was not less than that provided by postoperative CT scans. Although we used TEE in this patient for the purposes of another study, the application of TEE to noncardiac surgery is controversial [6,7]. Nevertheless, it is important for anesthesiologists not to miss the signs of this rare complication; sudden onset of hypotension or volume loss with unknown cause. Once AAD is suspected, TEE examination should be undertaken immediately, because AAD tends to have a lethal outcome, such as cardiac tamponade and shock, without early diagnosis. References 1. Strichartz SD, Gelabert HA, Moore WS (1990) Retrograde aortic dissection with bilateral renal artery occlusion after repair of infrarenal aortic aneurysm. J Vasc Surg 12:56-59 2. Fukui D, Urayama H, Kitahara H, Takano T, Kawano T, Sakaguchi M, Amano J (2003) Retrograde aortic dissection as a complication of abdominal aortic aneurysm surgery (in Japanese). Jpn J Cardiovasc Surg 32 (Suppl):416 3. Metha RH, To the editor: Acute aortic dissection (AAD) is a rare complication that occurs during open abdominal aortic aneurysm (AAA) repair [1,2]. We report a case of intraoperative retrograde aortic dissection that occurred during elective abdominal aortic aneurysmectomy. Detection of AAD by transesophageal echocardiography (TEE) led to rapid initiation of treatment.A 73-year-old man was operated f...