Hai-Tao Lu

Microvessel changes after post-ischemic benign and malignant hyperemia: experimental study in rats

BackgroundThe present investigation was designed to elucidate the use of dynamic contrast enhanced perfusion MR imaging (DCE pMRI) in characterizing hyperemia, including microvessel changes, and to examine whether DCE pMRI can predict benign or malignant hyperemia.MethodsSprague-Dawley rats underwent middle cerebral artery occlusion (MCAO) by intraluminal suture placement. All rats were randomized to 4 groups: MCAO for 0.5 hours followed by saline treatment (10 ml/kg; group 1); MCAO for 3 hours followed by treatment with saline (group 2) or urokinase (25000 IU/kg; group 3); and MCAO for 6 hours followed by urokinase treatment (group 4). Relative cerebral blood volume (rCBV) and relative maximum slope of increase of the signal intensity time curve (rMSI) were quantitatively analyzed from MRI. Microvessel diameter and blood-brain barrier disruption obtained by laser scanning confocal microscopy (LSCM) as well as transmission electron microscopy (TEM) were obtained for correlative study.ResultsBenign hyperemia was noticed only in group 1; malignant hyperemia was seen in group 3. Although the rCBV of malignant hyperemia was slightly higher than in benign hyperemia (P > 0.05), the rMSI, on the other hand, was significantly lower (P < 0.05). Fluoro-isothiocyanate dextran (FITC-dextran) extravasations, marked glial end-foot process swelling, and significant vasodilatation were seen in malignant hyperemia, while no or mild leakage of FITC-dextran and slight glial end-foot process swelling occurred in benign hyperemia.ConclusionOur findings indicate that DCE pMRI can characterize post-ischemic hyperemia and correlates well with microvascular damage.

Runoff detected by magnetic resonance angiography as an indicator for better recanalization outcomes in below-the-knee chronic total occlusions in diabetic patients.

Purpose: To compare the feasibility and efficacy of recanalizing below-the-knee (BTK) chronic total occlusions (CTOs) between patients with good or poor distal runoff based on magnetic resonance angiography (MRA) scans. Methods: Two hundred long-segment BTK CTOs in 171 limbs of 113 diabetic patients (58 men; mean age 69.8±1.9 years) were divided into good distal runoff (GDR: 119 lesions, 98 limbs) or poor distal runoff groups (PDR: 81 lesions, 73 limbs) based on baseline MRA findings. After angioplasty, modified thrombolysis in myocardial ischemia (mTIMI) grades and ankle-brachial index (ABI) were used to assess immediate outcomes. Regularly scheduled duplex or MRA imaging was performed in follow-up. The restenosis and limb salvage rates were compared. Results: The success rates were 93.3% and 87.7% in the GDR and PDR groups, respectively (p=0.21); subintimal angioplasty was more common in the PDR group (93.0% vs. 63.1%, p<0.01). Completion angiography indicated an mTIMI grade 3 blood flow in 71.2% lesions in the GDR patients and in 52.1% in the PDR (p=0.01) group. Improvement in the ABI was greater in the GDR limbs (p<0.001 vs. PDR). Mean imaging follow-up was 10.8±6.9 months in the GDR group and 11.1±6.6 months in the PDR group. Kaplan-Meier analysis showed a better restenosis-free rate in the GDR group (80.6% vs. 61.7%; p=0.02) at 12 months and for lesions with mTIMI grade 3 flow (p<0.01). At 24 months, Kaplan-Meier analysis revealed a better limb salvage rate in the GDR group (84.2% vs. 54.6%; p=0.02). Conclusion: Distal runoff detected using MRA could be a predictor for successful intraluminal recanalization, better distal tissue perfusion, improved long-term patency, and better limb salvage for patients with BTK CTOs.

Reconstruction of the Internal Carotid Artery After Treatment of Complex Traumatic Direct Carotid-Cavernous Fistulas With the Willis Covered Stent: A Retrospective Study With Long-Term Follow-up.

BACKGROUND Endovascular treatment of complex traumatic direct carotid-cavernous fistulas (TDCCFs) is a challenge. OBJECTIVE To evaluate the long-term efficacy of the Willis covered stent in endovascular treatment of complex TDCCFs, focusing on reconstruction and preservation of the internal carotid artery. METHODS During the past 8 years, 25 patients with 27 TDCCFs who previously had unsuccessful treatment of fistulas with detachable balloons received endovascular treatment with Willis covered stents. The efficacy, complications, in-stent stenosis, angiographic, and clinical follow-up results were evaluated retrospectively between 6 and 88 months (mean, 43.8 months) after the stent placement. RESULTS The technical success rate of stenting placement was 100%. Forty-four Willis covered stents were implanted into the target artery of 27 TDCCFs. Complete exclusion was achieved in 16 patients with 17 TDCCFs immediately after the stent placement, with transient endoleaks in 10 TDCCFs. Redilation was performed in 6 TDCCFs, and additional stents were implanted in the other 4 TDCCFs for endoleak exclusion. The initial angiographic results showed complete exclusion of fistulas with preservation of the internal carotid artery in 24 patients with 26 TDCCFs. One patient in whom complete occlusion initially was achieved subsequently experienced a delayed endoleak, which required placement of an additional stent. The angiographic follow-up results (mean, 30.3 months) demonstrated complete exclusion in all 27 TDCCFs, with patency of internal carotid artery in 23 patients. The clinical follow-up demonstrated a full recovery in 23 patients and improvement in 2 patients. CONCLUSION The use of Willis covered stents was confirmed to be effective, safe, and a curative approach for endovascular treatment of complex TDCCFs and internal carotid artery reconstruction. ABBREVIATIONS DB, detachable balloonEVT, endovascular treatmentICA, internal carotid arteryn-BCA, N-butyl cyanoacrylateTDCCF, traumatic direct carotid-cavernous fistula.

Infrainguinal Endovascular Recanalization: Risk Factors for Arterial Thromboembolic Occlusions and Efficacy of Percutaneous Aspiration Thrombectomy

PURPOSE To investigate factors predictive of thromboembolic occlusions and evaluate the efficacy of percutaneous aspiration thrombectomy (PAT) for infrainguinal thromboembolic occlusions in patients undergoing endovascular recanalization (EVR). MATERIALS AND METHODS In this single-center retrospective study, 23 patients who underwent PAT for thromboembolism during EVR and 237 patients who underwent successful EVR without thromboembolic occlusions (control group) were enrolled. Immediate posttreatment and follow-up outcomes between groups were compared. Multivariate analysis was performed to identify factors predictive of thromboembolic occlusions. Technical success of PAT was defined as achievement of < 30% residual stenosis and restoration of modified thrombolysis in myocardial infarction grade 3 flow. RESULTS The technical success rate was 95.7% in the PAT group. After intervention, ankle brachial index (ABI), restoration of blood flow, and improvement in dorsal/plantar arterial pulse score showed no significant differences between the PAT and control groups. During follow-up, no significant differences were observed between groups in improvement of sustained ABI and maximum walking distance, ulcer healing, restenosis/occlusion and limb salvage rates, and pain relief in patients with critical ischemia. Stenosis greater than 90% with lesion occlusion (odds ratio, 12.891; 95% confidence interval, 1.676-99.161; P = .014) and intraluminal angioplasty (odds ratio, 18.423; 95% confidence interval, 2.408-140.942; P = .005) were associated with a high incidence of thromboembolism. CONCLUSIONS Stenosis greater than 90% with lesion occlusion and intraluminal angioplasty may be factors predictive of thromboembolic occlusions. PAT is a safe and effective treatment for thromboembolism during infrainguinal arterial EVR.

Cerebral Venous Sinus Thrombosis Involving the Straight Sinus May Result in Infarction and/or Hemorrhage

Aim: We retrospectively investigated the clinical profiles and neuroimaging data of patients with documented cerebral venous sinus thrombosis (CVST) to analyze the relationship between the sites of CVST and clinical manifestations. Methods: A total of 68 patients, who were examined and treated at our hospital, were identified after review and their data were retrospectively analyzed. Results: Initial non-contrast CT scan showed a definite spontaneous hyperdensity of one or several sinuses in 47 patients (69.1%) and was normal in the remaining patients (30.9%). Furthermore, the χ2 test revealed a significant difference (p = 0.001) in the infarction or hemorrhage rate between the patients with straight sinus thrombosis (SST; 19 of 28, 67.8%) and other subjects (9 of 39, 23.1%). Moreover, patients with SST had a 6.33-fold (95% CI 2.18-18.4) increased risk of infarction or hemorrhage. Conclusion: Our data suggested that infarction and/or hemorrhage was more common in CVST patients with SST.

Retrograde Transplantar Arch Angioplasty of Below-the-Knee Arterial Occlusions : Outcomes Compared to Anterograde Recanalization

RATIONALE AND OBJECTIVES To compare the clinical outcomes of retrograde transplantar arch angioplasty and conventional below-the-knee (BTK) anterograde recanalization. MATERIALS AND METHODS One hundred twelve limbs in 96 patients underwent attempt at antegrade tibial angioplasty. Among 27 technical failures, retrograde trans-dorsal or -planter percutaneous transluminal angioplasty was attempted in 22 limbs. Ankle-brachial index (ABI), thrombolysis in myocardial infarction (TIMI) flow grade, and dorsal/plantar arterial pulse score improvement were compared immediately after the procedures between patients received successful anterograde angioplasty (anterograde angioplasty group [AAG], 85 limbs in 71 patients) and retrograde angioplasty (retrograde angioplasty group [RAG], 22 limbs in 20 patients). Target vessel restenosis and limb salvage were observed during follow-up. RESULTS Primary technical success rate was 75.9% in the RAG (vs. 74.0% AAG, P > .05). ABI improved from 0.55 ± 0.21 to 0.93 ± 0.19 in the RAG (vs. 0.56 ± 0.14 to 0.89 ± 0.18 AAG, P > .05). TIMI flow grade demonstrated greater reperfusion of distal foot tissue in the RAG (2.3 ± 0.8 vs. 1.0 ± 0.8, P < .05). Primary patency rates at 12 and 24 months were 63.6% (14 of 22) and 45.5% (10 of 22) in the RAG and 52.9% (45 of 85) and 37.6% (32 of 85) in the AAG, respectively (P > .05). Kaplan-Meier analysis after 24 months found limb salvage rates of 93.8% in the RAG and 96.5% in the AAG (P > .05). CONCLUSIONS Retrograde transplantar arch angioplasty achieved better immediate blood flow and similar ABI improvement, primary patency rate, and limb salvage rate compared to conventional transtibial angioplasty for BTK occlusions. This could become a supplementary technique when anterograde angioplasty fails.

Morphological characteristics of chronic total occlusion: predictors of different strategies for long-segment femoral arterial occlusions

ObjectivesTo investigate morphological characteristics used to predict recanalisation strategies in long-segment (>10 cm) femoral chronic total occlusion (LSF-CTO) angioplasty.MethodsWe retrospectively evaluated a range of morphological CTA and DSA features in patients who underwent recanalisation of LSF-CTO. The stage of CTO was classified into early (3–12 months) and late (>12 months) according to estimated duration. Characteristics including stump morphology, lesion length and calcification, proximal side branches, collaterals circulation, runoff vessels and concomitant arterial occlusion were used as predictors, and multivariate logistic regression analysis was performed to identify variables associated with late-stage CTO and retrograde technique.ResultsA total of 119 patients with 137 CTOs in 137 limbs were enrolled. Overall, successful recanalisation was achieved in 122 CTOs (89.1%). Flush occlusion [odds ratio (OR) 2.958; 95% confidence interval (CI) 1.172–7.465; p = 0.022], large collateral (OR 2.778; 95% CI 1.201–6.427; p = 0.017) and TransAtlantic Inter-Society Consensus II class D (TASC D) lesion (OR 1.743; 95% CI 1.019–2.981; p = 0.042) were predictors for late-stage CTO. Flush occlusion (OR 75.278; 95% CI 10.664–531.384; p < 0.001) and large collateral (OR 23.213; 95% CI 3.236–166.523; p = 0.002) were associated with high likelihood for retrograde approach.ConclusionsFlush occlusion and large collateral were associated with a CTO at late-stage which may require retrograde recanalisation.Key points• CTO morphological characteristics help estimate lesion duration and optimise recanalisation strategies.• Flush occlusion and large collateral is associated with late-stage CTO and retrograde recanalisation.• Application of anterograde and retrograde recanalisation for long-segment femoral CTO is effective.The original version of this article unfortunately contained mistakes. The legends to Figs. 2–4 were incorrectly interchanged. The correct versions are given below. The original article has been corrected.

Subarachnoid Hemorrhage in Patients with Good Clinical Grade: Accuracy of 3.0-T MR Angiography for Detection and Characterization

Purpose To evaluate the diagnostic accuracy of aneurysm detection and the fidelity of morphologic characterization of three-dimensional (3D) time-of-flight (TOF) magnetic resonance (MR) angiography at 3.0 T in patients with a Glasgow coma score of 15 and noncontrast material-enhanced computed tomography (CT) findings that showed acute nontraumatic subarachnoid hemorrhage. Materials and Methods The institutional review board approved this prospective study, and patients provided informed consent. A total of 277 patients who had not experienced trauma but in whom nonenhanced CT showed subarachnoid hemorrhage, who had a Glasgow coma score of 15, and who underwent both 3D TOF MR angiography and digital subtraction angiography (DSA) (the reference standard) were included. Three observers who were blinded to clinical and DSA results independently analyzed all 3D TOF MR angiographic data sets. The receiver operating characteristic curve was applied to analysis of the detection of aneurysms with 3D TOF MR angiography by using patient- and aneurysm-based evaluations. Multivariate logistic regression analysis was performed to identify aneurysm-specific variables, including size, shape (daughter sac/lobulation/margin), neck width (wide if > 4 mm or if fundus-to-neck ratio was < 2), and relation to adjacent artery, that significantly affected morphologic assessment with 3D TOF MR angiography. Results Aneurysms were depicted with DSA in 225 patients. In patient- and aneurysm-based evaluations, respectively, 3D TOF MR angiography yielded accuracies of 96.8% (268 of 277) and 96.6% (309 of 320), sensitivities of 98.2% (219 of 223) and 98.1% (260 of 265), specificities of 91% (49 of 54) and 89% (49 of 55), positive predictive values of 97.8% (219 of 224) and 97.7% (260 of 266), and negative predictive values of 92% (49 of 53) and 91% (49 of 54). Accuracy of display of morphologic features was 92.5% (236 of 255) for size, 86.3% (220 of 255) for neck width, 94.5% for shape (241 of 255), and 96.9% (247 of 255) for relationship to adjacent vessel. Width of aneurysm neck was the only variable that significantly affected the morphologic assessment of 3D TOF MR angiography (odds ratio, 0.378; 95% confidence interval: 0.337, 8.347; P = .004). Conclusion Three-dimensional TOF MR angiography can accurately depict cerebral aneurysms and accurately display their morphologic features in stable patients with subarachnoid hemorrhage and a Glasgow coma score of 15.

Rendezvous technique for recanalization of long-segmental chronic total occlusion above the knee following unsuccessful standard angioplasty

Purpose To assess the technical feasibility and efficacy of the rendezvous technique, a type of subintimal retrograde wiring, for the treatment of long-segmental chronic total occlusions above the knee following unsuccessful standard angioplasty. Methods The rendezvous technique was attempted in eight limbs of eight patients with chronic total occlusions above the knee after standard angioplasty failed. The clinical symptoms and ankle-brachial index were compared before and after the procedure. At follow-up, pain relief, wound healing, limb salvage, and the presence of restenosis of the target vessels were evaluated. Results The rendezvous technique was performed successfully in seven patients (87.5%) and failed in one patient (12.5%). Foot pain improved in all seven patients who underwent successful treatment, with ankle-brachial indexes improving from 0.23 ± 0.13 before to 0.71 ± 0.09 after the procedure (P < 0.001). At the end of the follow-up period, the visual analogue scale improved from 6.86 ± 1.57 to 1.57 ± 1.27 (P < 0.001). Non-healing ulcers in three patients either healed (n = 2) or improved (n = 1). No major amputation was necessary. Kaplan–Meier analyses revealed that stenosis-free rate was 83.3% at six months and 41.7% at 12 months. Conclusion The rendezvous technique is a feasible and effective treatment for chronic total occlusions above the knee when standard angioplasty fails.

Predictors for Better Blood-Flow Restoration of Long-Segmental Below-the-Knee Chronic Total Occlusions after Endovascular Therapy in Diabetic Patients

Objective To prospectively investigate predictors for good restoration of blood flow of below-the-knee (BTK) chronic total occlusions (CTOs) after endovascular therapy in diabetes mellitus (DM) patients. Materials and Methods A total of 120 long-segmental (≥ 5 cm) BTK, CTOs in 81 patients who underwent recanalization were included in this study. After angioplasty, blood-flow restoration was assessed using modified thrombolysis in myocardial ischemia grades and classified as good flow (grade 3) and poor flow (grade 1/2). One hundred and six CTOs with successful recanalization were divided into a good flow group (GFG; n = 68) and poor flow group (PFG; n = 38). Multivariate logistic regression analyses were undertaken to determine independent predictors of blood-flow restoration. Receiver operating characteristic curves were constructed to determine the best cutoff value. The prevalence of target-lesion restenosis during follow-up was compared between two groups. Results Univariate analyses suggested that CTOs in GFG were characterized by lighter limb ischemia (p = 0.03), shorter course of ischemic symptoms (p < 0.01) and lesion length (p = 0.04), more frequent use of intraluminal angioplasty (p = 0.03), and higher runoff score (p < 0.01) than those in PFG. Multivariate regression analyses suggested that distal runoffs (p = 0.001; odds ratio [OR], 10.32; 95% confidence interval [CI]: 4.082–26.071) and lesion length (p < 0.001; OR, 1.26; 95% CI: 1.091–1.449) were independent predictors for good flow restoration. Kaplan-Meier analyses at 12 months showed a higher prevalence of non-restenosis in GFG (p < 0.01). Conclusion Distal runoffs and lesion length are independent predictors for good flow restoration for long-segmental BTK, CTOs in DM patients who receive endovascular therapy.