Relation between B-mode gray-scale median and clinical features of carotid stenosis vulnerability.

BACKGROUND: Vulnerability of the carotid plaque might be useful as a predictor for ischemic stroke risk. The gray-scale median (GSM) of the carotid plaque at B-mode imaging has been described as an objective tool to quantify vulnerability. However, its use is disputed in the published literature. This study sought to validate the GSM as a predictor for carotid plaque vulnerability. METHODS: We included 89 consecutive patients (64 men; mean ± SD age: 68 ± 1 years) who were evaluated for carotid endarterectomy. The GSM was derived from preoperative B-mode images and related to the presence of clinical symptoms, the presence of ipsilateral infarction on neuroimaging, and to the number of intraoperative ipsilateral microemboli (ME) detected by transcranial Doppler ultrasonography. In addition, we combined the GSM with its standard deviation (GSM-SD), which we hypothesized to be a measure for plaque heterogeneity and thereby vulnerability. RESULTS: B-mode imaging revealed a wide variety in GSM among all plaques (median: 36; range: 6-89). The GSM could not be related to cardiovascular risk factors and was not different between symptomatic and asymptomatic patients (37.8 ± 8.9 vs 37.6 ± 17.1; P = 0.97). The GSM of plaques in patients with ipsilateral ischemic lesions on neuroimaging did also not differ from plaques in patients without (36.0 ± 14.6 vs 37.8 ± 16.9; P = 0.64). Finally, no relation between GSM and the presence of intraoperative ME (Spearman correlation; n = 73; ρ = 0.039; P = 0.75) was found. Combining GSM with its GSM-SD also could not identify more vulnerable plaques. CONCLUSIONS: No relation was found between the GSM and any clinical, radiologic, or intra- and postoperative neurologic phenomena. These data showed no additional value of the use of GSM in evaluating plaque vulnerability.

Patient-related factors influencing patency of autogenous brachiocephalic haemodialysis fistulas.

OBJECTIVE: The objective of this study was to analyse the outcome of autogenous brachiocephalic fistula for dialysis purposes and to determine modifiable and non-modifiable patient-related factors of influence on the patency of a newly created fistula. DESIGN OF STUDY: A single-centre retrospective cohort study with the aim of determining patient-related factors of influence on primary failure, primary, primary assisted and secondary patency of autogenous brachiocephalic fistulas. Seventeen patient-related variables were determined by means of univariate analysis, variables reaching significance were then entered in a multivariate Cox-regression model. RESULTS: Between October 2005-October 2015, 231 autogenous brachiocephalic fistulas were created in 228 patients. Mean age was 61.3 years (20.3-88.2 years). Patency was calculated using Kaplan-Meier analysis. Primary failure occurred in 38 out of 231 created fistulas (16.5%). The primary, primary assisted and secondary patency rates at six months were 78 ± 3%, 93 ± 2%, and 95 ± 1%, respectively. At 12 months, they were 63 ± 3%, 89 ± 2%, and 92 ± 2%, and at 24 months 47 ± 4%, 84 ± 3%, and 89 ± 2%. The non-modifiable factors, diabetes mellitus and mean cephalic vein diameter were identified as a predictor for failure influencing primary and secondary patency. The preoperative use of anticoagulation was identified as a modifiable factor for failure. CONCLUSIONS: This study identified several non-modifiable and modifiable factors of interest to the clinician deciding on which type of haemodialysis fistula is most suitable for an individual patient. Meticulous preoperative work-up, a surveillance programme, and a dedicated multidisciplinary team can be of great importance in achieving better patency rates.

Overestimation of contralateral internal carotid artery stenosis before ipsilateral surgical endarterectomy.

OBJECTIVE: The aim of this study was to investigate a possible overestimation of the degree of contralateral carotid artery stenosis by duplex in patients with significant bilateral carotid stenoses who are to undergo carotid endarterectomy (CEA). METHODS: A retrospective analysis was performed of all patients undergoing CEA in our center over a period of 11 years. Pre- and postoperative duplex ultrasonography measurements of peak systolic velocity (PSV) and end diastolic velocity (EDV) were compared and used to classify the degree of stenosis. Univariate analysis was performed to indicate possible predictors for contralateral stenosis overestimation. RESULTS: A total of 384 CEA procedures in 357 patients were performed in our hospital. Pre- and postoperative bilateral duplex measurements were available in 135 patients. Forty-four out of 135 patients (33%) were preoperatively identified as having significant stenosis (>60%) of the internal carotid artery on both sides. In these patients, postoperative duplex measurements of the contralateral carotid showed a decrease in mean (SD) PSV from 2.53 (1.11) m s(-1) to 1.97 (0.87) m s(-1) (P<0.01) and a decrease in EDV from 0.87 (0.60) m s(-1) to 0.60 (0.36) m s(-1) (P<0.01). The absolute changes in contralateral PSV and EDV after CEA were larger among patients with a higher degree of stenosis preoperatively. These changes led to reclassification of stenosis to a lesser degree in 24 (55%) patients. In 16 cases (36%), this resulted in a measured stenosis on the contralateral side of less than 60%. CONCLUSIONS: One-third of the patients with duplex measurements consistent with bilateral significant carotid stenosis did not have a significant contralateral stenosis by duplex after CEA. Therefore, additional postoperative duplex measurement is advisable before planning contralateral CEA.

Long-term locoregional vascular morbidity after isolated limb perfusion and external-beam radiotherapy for soft tissue sarcoma of the extremity.

BACKGROUND: Isolated limb perfusion (ILP) with tumor necrosis factor alpha (TNF-alpha) and melphalan, followed by delayed surgical resection and adjuvant external-beam radiotherapy is a limb salvage treatment strategy for locally advanced soft tissue sarcomas. The long-term vascular side effects of this combined procedure were evaluated. METHODS: Thirty-two patients were treated for a locally advanced sarcoma of the upper (n = 5) or lower limb (n = 27). All patients underwent a noninvasive vascular work-up. RESULTS: Five patients underwent a leg amputation, in two cases due to critical leg ischemia 10 years after ILP. With a median follow-up of 88 (range, 17-159) months, none of the patients with a salvaged lower leg (n = 22) experienced peripheral arterial occlusive disease. Ankle-brachial index (ABI) measurements in the involved leg (median, 1.02; range, .50-1.20) showed a significant decrease compared with the contralateral leg (median, 1.09; range, .91-1.36, P = .001). Pulsatility index (PI) was decreased in the treated leg in 17 of 22 patients at the femoral level (median, 6.30; range, 2.1-23.9 vs. median, 7.35; range, 4.8-21.9; P = .011) and in 19 of 20 patients at popliteal level (median, 8.35; range, 0-21.4 vs. median, 10.95; range, 8.0-32.6; P < .0005). In patients with follow-up of >5 years, there was more often a decrease in ABI (P = .024) and PI at femoral level (P = .011). CONCLUSIONS: ILP followed by resection and external-beam radiotherapy can lead to major late vascular morbidity that requires amputation. Objective measurements show a time-related decrease of ABI and femoral PI in the treated extremity.

Within-session and between-session variability of haemodialysis shunt flow measurements.

BACKGROUND: Knowledge of the variability of a measurement method is essential for its clinical application. We investigated the variability of shunt flow measurements, since this is a relatively neglected area in the literature. In particular, no direct comparison of between-session and within-session variability was available until now. METHODS: During two consecutive dialysis sessions, shunt flow was measured three times with the ultrasound dilution method in 24 chronic haemodialysis patients with various types of shunts. Needle orientation and blood pressure at the time of flow measurement were recorded. In these patients, shunt flow was also measured three times by duplex ultrasound before the first dialysis session. RESULTS: The within-session variation coefficient (VC) of shunt flow measured with ultrasound dilution was 7.7%, whereas the between-session VC was 14.2% (n.s.). The within-session VC of Doppler shunt flow was 11.6% which was not significantly different from the corresponding figure of ultrasound dilution. Analysis of subgroups showed that changes in needle orientation caused large differences between sessions in radiocephalic fistulas but not in brachiocephalic fistulas: in the radiocephalic fistulas with the same needle orientation, VC was 6.7%, but with different needle orientation it was 23.5% (P = 0.02); the corresponding figures for brachiocephalic fistulas were 14.6% (same direction) and 11.4% (different direction, n.s.). CONCLUSION: Reproducibility of shunt flow measurements between dialysis sessions in radiocephalic fistulas is critically dependent on similar needle orientation. With similar needle position and correction for blood pressure differences, flow changes of more than 20-25% are likely to reflect true flow changes. The variability of duplex flow measurements is at least as large as that of the ultrasound dilution method.