Natural history of the residual infrarenal aorta after infrarenal abdominal aortic aneurysm repair.

PURPOSE: We determined the natural history of the residual native infrarenal aortic segment after conventional abdominal aortic aneurysm (AAA) repair. METHODS: For the retrospective arteriographic case series, 800 hundred translumbar aortograms (TLAs) were obtained for 272 patients, before and after conventional AAA repair. The main outcome measures were changes in the aortographic diameter and the length of the infrarenal aortic segment, corrected and uncorrected for magnification by normalization to the first lumbar vertebral body height. RESULTS: The mean follow-up time from the preoperative TLA to the most recent postoperative TLA was 42 months (range, 1 to 257 months). Vertebral body height did not change (p = 0.35). The length of the native infrarenal aorta cephalad to the proximal anastomosis increased a mean of 3 mm, from 23 to 26 mm (p = 0.001). However, in 115 patients (43%), this aortic segment elongated more than 5 mm, and in 63 patients (24%), it elongated more than 10 mm. The native residual infrarenal aorta above the proximal anastomosis dilated a mean of 1 mm, from 23 to 24 mm (p = 0.001), but in 21 patients (8%), it dilated more than 5 mm. There was a weak positive correlation between the increase in residual native aortic diameter and duration of follow-up. There was a negative correlation between this increase and the initial size. The diameters of the proximal anastomosis and proximal graft did not change. Marked variability in the changes in aortic dimensions was observed. CONCLUSIONS: A mean period of 42 months after conventional AAA repair, the native infrarenal aortic segment elongates and dilates. Although such enlargement is statistically significant, the average increase appears to be small. However, residual aortic cuff diameter increased more than 5 mm and neck length more than 10 mm in a significant number of patients, with potentially serious implications for endovascular treatment of AAA.

Noninvasive venous testing in the diagnosis of pulmonary embolism: the impact on decisionmaking.

PURPOSE: To characterize the use and utility of lower extremity noninvasive venous testing (NIVT) in the diagnosis of pulmonary embolism (PE). METHODS: The study is a retrospective case series of consecutive patients in whom PE was suspected who were referred to a large, urban tertiary care center for NIVT. The main outcome measures of the study were the rate of positive results of NIVT, the amount of new information provided by NIVT, and the frequency of management changes that were attributable to NIVT. RESULTS: Forty-one of 450 patients (9%) had deep venous thrombosis (DVT) by NIVT. The prevalence of DVT by NIVT among patients not evaluated by ventilation/perfusion (V/Q) scanning was 8%. The prevalence of DVT by NIVT among patients with a high-probability V/Q scan result before NIVT was 39%, but no management decisions in this group were based on a positive NIVT result and only two decisions were based on negative NIVT results. The prevalence of DVT according to NIVT among patients who had a negative "diagnostic" (low, or very low probability, or normal) result of V/Q scan before NIVT was 2%. The overall frequency of management changes attributed to NIVT was only 2.5%. In the remaining 97% of patients, management was determined by the result of V/Q scanning or of subsequent pulmonary arteriography. CONCLUSIONS: In patients in whom PE is suspected, results of NIVT are usually negative for acute DVT. Management decisions are almost always based on V/Q scan or results of pulmonary arteriography and not on NIVT. The utility of NIVT to identify DVT in these patients appears limited, and a more selective approach to its application for the diagnosis of PE should be considered.

Intraoperative duplex scanning reduces both residual stenosis and postoperative morbidity of carotid endarterectomy.

To evaluate the effect of intraoperative duplex scanning (IDS) on the incidence of perioperative and postoperative strokes as well as residual and recurrent stenosis, we reviewed 141 patients who underwent 152 consecutive carotid endarterectomies (CEAs) between July, 1990 and June, 1995. Follow-up of 129 cases, with a mean follow-up of two years, revealed no perioperative deaths and three strokes for a combined perioperative stroke-death rate of 2.3 per cent. In 50% (64 of 129) of the CEAs, intraoperative duplex scans were obtained based on the attending surgeon's preference. We noted that the incidence of residual stenosis (>50% stenosis on the first duplex after CEA) was significantly lower in those undergoing IDS (3/64) versus those without IDS (13/65) (P < 0.05; risk ratio 0.31; 95% confidence interval 0.11, 0.91). IDS resulted in a modification of the internal carotid reconstruction in 9 per cent (6 of 64) of the cases with no resulting postoperative strokes or residual/recurrent stenosis. There was no significant difference in the frequency of recurrent stenosis (>50% stenosis after a normal duplex) in the two groups (3 of 64 with vs 2 of 65 without). Of patients not undergoing intraoperative scanning, four underwent redo CEA for symptomatic residual stenosis due to a retained intimal flap in the internal carotid artery. There were three strokes observed within 30 days of the initial CEA, all of which occurred in patients who did not undergo IDS at their initial operation. We conclude that IDS can identify technical defects following internal carotid reconstruction, thereby reducing the incidence of both residual stenosis and postoperative morbidity in patients undergoing CEA.

Intraoperative duplex scanning reduces the incidence of residual stenosis after carotid endarterectomy.

We studied the effect of intraoperative duplex scanning on the incidence of residual and recurrent stenosis and stroke after carotid endarterectomy (CEA). We retrospectively analyzed 98 veteran patients undergoing 106 consecutive CEAs between July 1990 and June 1994. Follow-up duplex scans were available for 86 cases (81%, mean follow-up 20 months). There were no perioperative deaths. Intraoperative duplex scans were obtained in 39 (45%) of 86 CEAs. The incidence of residual stenosis was lower in the patients scanned at the time of surgery (O of 39) than in those who underwent CEA without intraoperative scan (7 of 47, P < 0.04). One patient who did not receive intraoperative duplex scanning underwent redo CEA for symptomatic residual stenosis due to an intimal flap of the carotid artery. Operative management was changed in 9 of 39 cases because of abnormal intraoperative duplex scans, with no postoperative strokes or residual/recurrent stenosis. The incidence of recurrent stenosis was not different in the two groups (2 of 39 vs 2 of 47, ns). There was no difference in stroke rate. There were three strokes, one perioperative and two postoperative (mean 3.5 months, range 0.5 to 9). Two of the three patients did not undergo an intraoperative duplex scan, but none had developed restenosis >50% over a mean of 21 months of follow-up. Intraoperative duplex scanning significantly reduced the incidence of residual stenosis, but did not affect the incidence of recurrent stenosis or stroke following CEA.

Examination of the eyelid closure defect in trisomy 16 mice.

A characteristic feature of trisomy 16 mouse conceptuses is a failure of their eyelids to close. This defect was investigated by examining ocular development in serially sectioned heads of trisomy 16 and normal littermate fetuses from 10 to 18 gestational days. Other heads were examined by using scanning electron microscopy. Between 10 and 15 days, trisomy 16 ocular structures were delayed, but there was no striking abnormal morphology. At 16 days, when the eyelids were closed and fused in normal mice, trisomic eyes had a large cell mass near the inner canthus that protruded between the open lids. The mass was covered by bulbar conjunctiva and cells of the mass were continuous with developing corneal tissue. The mass was not present in the eyes of normal mice on any gestational day and was not present in trisomic eyes at 17 and 18 days, when the lids began to show varying degrees of closure. Based on its positioning at the inner canthus, the mass may represent a transient hyperplasia of the developing semilunar fold which physically impedes lid closure in the trisomic conceptuses. Previously, the defect has been attributed to the trisomy 16 conceptus's overall pattern of growth retardation and delayed development. Masses such as those seen in the trisomic eyes have not been observed in other murine lid-gap defects that have been investigated. A second finding in this study is that trisomic eyes are positioned more superiorly in the head than normal eyes. This variation may be related to alterations in cranial base morphology that are associated with trisomy 16.