Zhiqing Zhao

Endovascular Repair of Ascending Aortic Dissection : A Novel Treatment Option for Patients Judged Unfit for Direct Surgical Repair

OBJECTIVES This paper sought to report the outcomes of patients who are considered unfit for urgent surgical repair of ascending aortic dissections (AADs) who were treated using a novel endovascular repair strategy. BACKGROUND AAD is best treated by direct surgical repair. Patients who are unable to undergo this form of treatment have poor prognoses. Previously, clinical case reports related to endovascular repair of AAD have been controversial. METHODS Between May 2009 and January 2011, 41 consecutive patients with AAD were treated in our institution. Fifteen patients were considered poor candidates for direct surgical repair and subsequently underwent the endovascular repair. RESULTS The nature of the referral process to our tertiary care facility made the median time from aortic dissection onset to treatment 25.5 days (range: 6 to 353 days). Dissections in 5 patients (33.3%) were considered acute, and those in 10 patients (66.7%) were considered chronic. The rate of successful stent-graft deployment was 100%, and there were no major morbidities or deaths in the perioperative period. Median follow-up was 26 months (range: 16 to 35 months). One new dissection occurred in the aortic arch at 3 months and was treated with a branched endograft. Significant enlargements of true lumens and decreases of false lumens and overall thoracic aorta were noted after the procedures. CONCLUSIONS Endovascular repair of AAD was an appropriate treatment option in patients who were considered poor candidates for traditional direct surgical repair by the clinical criteria used in our institution. A larger series of cases with longer follow-up is needed to substantiate these results.

A microRNA profile comparison between thoracic aortic dissection and normal thoracic aorta indicates the potential role of microRNAs in contributing to thoracic aortic dissection pathogenesis

OBJECTIVES Our aim was to identify important microRNAs (miRNAs) that might play an important role in contributing to aortic dissection by conducting a miRNA profile comparison between thoracic aortic dissection (TAD) and normal thoracic aorta. METHODS The differentially expressed miRNA profiles of the aortic tissue between TAD patients (n = 6) and age-matched donors without aortic diseases (NA; n = 6) were analyzed by miRNA microarray. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was further performed to verify the expression of 12 selected miRNAs with an increased number of samples (TAD n = 12; NA n = 8). The potential targets of the differentially expressed miRNAs were predicted using computational searches. Bioinformatic analyses of the predicted target genes (gene ontology, pathway and network analysis) were done for further research. Additionally, Western blotting was performed to confirm the bioinformatics findings. RESULTS The miRNA microarray revealed differentially expressed miRNAs between the TAD and NA groups. In the TAD group, 18 miRNAs were upregulated and 56 were downregulated (fold change >2, P < .01). qRT-PCR verified statistically consistent expression of seven selected miRNAs with microarray analysis. Combined with our previous proteomics study, target gene prediction revealed that some miRNAs reciprocally expressed with their targeted proteins. Target gene-related pathway analysis showed a significant change in five pathways in the TAD group compared with the NA group, especially the focal adhesion and the mitogen-activated protein kinase (MAPK) signaling pathways. By further conducting miRNA gene network analysis, we found that the mir-29 and mir-30 families are likely to play a role in the regulation of these two pathways, respectively. CONCLUSIONS Our results indicate that miRNAs expression profiles in aortic media from TAD were significantly changed. These results may provide important insights into TAD disease mechanisms. This study also suggests that the focal adhesion and MAPK signaling pathways might play important roles in the pathogenesis of TAD.

A proteomic study of the aortic media in human thoracic aortic dissection: implication for oxidative stress.

OBJECTIVE The aortic media lesion is a key pathologic feature in thoracic aortic dissection. To identify key proteins in aortic media lesions that may contribute to its pathogenesis, we performed proteomic studies to find differentially expressed proteins in the media from diseased and normal thoracic aorta. METHODS Ascending aortic segments were obtained from patients with thoracic aortic dissection (n = 8) and age-matched normal donors (n = 6). The differentially expressed proteins of their media tissues were analyzed by 2-dimensional electrophoresis and mass spectrometry, and verified by Western blotting. Oxidative stress was measured by functional assays in a larger sample size (15 patients and 10 controls). RESULTS Image analysis of the protein profiles from 2-dimensional gels revealed 126 differentially expressed proteins, of which 26 were identified by mass spectrometry. Among them, extracellular superoxide dismutase, an enzyme involved in oxidative stress, was selected for further studies. Western blotting showed that extracellular superoxide dismutase expression was more than 50% lower in patient samples than in controls (P < .001). Superoxide dismutase activity was consistently decreased (P < .001) and lipid peroxidation was increased (P = .019) in patient media homogenates compared with that in controls. CONCLUSION Our results indicate that protein expression profiles in the aortic media from thoracic aortic dissection differ significantly from that of controls, which may provide important insights into the disease mechanisms. This study also suggests that increased oxidative stress may play an important role in the disease.

Endovascular Stent Placement for Treatment of Spontaneous Isolated Dissection of the Superior Mesenteric Artery

BACKGROUND Spontaneous isolated dissection of the superior mesenteric artery (SIDSMA) is a rare condition often associated with a poor prognosis. The goal of this study is to assess the efficacy of endovascular treatment of SIDSMA with stenting and investigate the possible therapeutic mechanisms involved. METHODS This is a retrospective review of all patients undergoing endovascular treatment of SIDSMA from January 2009 to December 2011. Patient demographics, history, clinical presentation, laboratory tests, image characteristics, endovascular treatments, and follow-up outcome were analyzed. RESULTS Twenty-four patients with symptoms were treated. All except 1 patient (23 of 24, 96%) underwent successful stent placement (16 with single stent and 7 with overlapping stents). A total of 30 stents (4 balloon-expanded and 26 self-expanding) were placed during the procedures. In the perioperative period and during follow-up, symptom relief was achieved in 20 (83%) patients, and abdominal pain remained unchanged in 4 (17%). No death or serious complications occurred. The median length of hospital stay and follow-up was 3.25 ± 2.23 days (range 2-7 days) and 13.15 ± 8.27 months (range 6-23 months), respectively. Computed tomography angiography (CTA) performed 6 months postoperatively revealed stent patency in 23 cases (100%), false lumen patency in 5 cases (22%), and new development of dissection in the SMA distal to the stent in 1 case (4%). No significant differences were observed in the incidence of false lumen patency between patients treated with a single stent and those treated with overlapping stents, and between patients with and without symptom relief (P > 0.05 for both). CONCLUSIONS For symptomatic SIDSMA patients without intra-abdominal hemorrhage and intestinal infarction, endovascular stent placement is a feasible treatment choice with a high success rate and good clinical outcome. Overlapping stenting may be proposed for patients with aneurysmal dilation. False lumen patency may occur in some cases during follow-up, but it does not affect improvement of SIDSMA symptoms.

Systematic Review and Meta-analysis of Carotid Artery Stenting Versus Endarterectomy for Carotid Stenosis: A Chronological and Worldwide Study

AbstractThere are disparities among the results of meta-analyses under different circumstances of carotid artery stenting (CAS) versus endarterectomy (CEA) for carotid stenosis. This study aimed to assess the efficacies of CAS and CEA for carotid stenosis at 5-year intervals and worldwide.Comparative studies simultaneously reporting CAS and CEA for carotid stenosis with at least 10 patients in each group were identified by searching PubMed and Embase in accordance with preferred reporting items for systematic reviews and meta-analyses guidelines, and by reviewing the reference lists of retrieved articles.The studies were stratified into different subgroups according to the publication year, location in which the study was mainly performed, and randomized and nonrandomized study designs.Thirty-five comparative studies encompassing 27,525 patients were identified. The risk ratios (RRs) of stroke/death when CAS was compared with CEA within 30 d of treatment were 1.51 (95% CI 1.32–1.74, P < 0.001) for overall, 1.50 (95% CI 1.14–1.98, P = 0.004) from 2011 to 2015, 1.61 (95% CI 1.35–1.91, P < 0.001) from 2006 to 2010, 1.59 (95% CI 1.27–1.99, P < 0.001) in North America, 1.50 (95% CI 1.24–1.81, P < 0.001) in Europe, 1.63 (95% CI 1.31–2.02, P < 0.001) for randomized, and 1.44 (95% CI 1.20–1.73, P < 0.001) for nonrandomized comparative studies. CEA decreased the risks of transient ischemic attack at 30 d (RR: 2.07, 95% CI 1.50–2.85, P < 0.001) and restenosis at 1-year (RR: 1.97, 95% CI 1.28–3.05, P = 0.002). Data from follow-up showed that the RRs of stroke/death were 0.74 (95% CI 0.55–0.99, P = 0.04) at 1 year, 1.24 (95% CI 1.04–1.46, P = 0.01) at 4 year, and 2.27 (95% CI 1.39–3.71, P = 0.001) at 10 year. This systematic review, compared with those of other meta-analyses, included all available comparative studies and analyzed them at 5-year intervals, in different continents, and under different study designs. Current evidence suggests that the efficacy of CEA is superior to CAS for freedom from stroke/death within 30 d, especially from 2006 to 2015, in North America and Europe. Meanwhile, the superiority was also observed for restenosis at 1-year, transient ischemic attack within 30 d, and stroke/death at 4- and 10-year follow-ups.

Double-chimney technology for treating secondary type I endoleak after endovascular repair for complicated thoracic aortic dissection

Endovascular repair continues to pose a formidable technical challenge in the cases of aneurysm, dissection, and proximal type I endoleak involving the aortic arch. During the process of covering the aortic arch by stent graft to achieve better sealing, maintaining blood flow to the vital supra-aortic branches is difficult. We present a case of successful endovascular treatment of secondary type I endoleak by a double-chimney technique in a 36-year-old woman who had previously undergone a complicated descending aortic dissection repair. This endovascular technology might offer a new option to simultaneously preserve the innominate artery and the left carotid artery for total reconstruction of the aortic arch.

Endovascular repair by customized branched stent-graft: A promising treatment for chronic aortic dissection involving the arch branches

OBJECTIVE There is no approved special endovascular device for use in preventing entry tears in the distal part of ascending aorta or in the aortic arch and preserving the arch branch arteries. Thus, we have designed a novel branched stent-graft, and herein report the initial clinical outcomes. METHODS Between August 2009 and January 2014, 51 patients with aortic dissections involving the aortic arch were treated by endovascular branched stent-grafts. There were 7 Stanford type A aortic dissections, 22 retrograde type A aortic dissections, and 22 Stanford type B aortic dissections (including 4 localized aortic arch dissections). All patients were treated while in the chronic phase (>2 weeks). RESULTS All of the proximal entry tears in the arch were successfully excluded, and all of the treated branch arteries remained patent. No new cerebral infarction occurred. There was 1 death from a retrograde type A dissection, occurring 6 days after the endovascular procedure. The median follow-up period was 44 months (range, 14-66 months). No additional complications or mortality occurred. Complete thrombosis in the false lumen of the aortic arch was formed in all patients, and significant true lumen recovery and false lumen shrinkage were demonstrated in different levels of the thoracic aorta according to computed tomography angiography at 1 year postsurgery (P < .001). CONCLUSIONS In patients with aortic dissection involving the arch branches, the customized branched stent-graft may provide a feasible endovascular treatment option. A larger series of cases with longer follow-up is needed to substantiate these results.

Restrictive bare stent for prevention of stent graft-induced distal redissection after thoracic endovascular aortic repair for type B aortic dissection.

BACKGROUND Stent graft-induced distal redissection (SIDR) is one of the major concerns in the durability of endovascular repair for complicated Stanford type B aortic dissection. The characteristics and means of prevention of this complication remain unknown. METHODS From April 1997 to March 2010, 674 patients with type B aortic dissections were treated primarily by thoracic endovascular aortic repair (TEVAR) at our center. Criteria for inclusion in this study were treatment primarily with TEVAR and an estimated mismatch rate (ratio of distal diameter of stent graft to long diameter of true lumen) greater than 120%. By this protocol, 465 patients were included in this study and were retrospectively analyzed. Among them, 266 patients were treated in the acute phase, and 199 were treated in the chronic phase. RESULTS A total of 311 patients were treated with standard TEVAR and 154 patients with TEVAR + restrictive bare stent (RBS). The preoperative mismatch rate (measured as the preoperative long diameter of the true lumen at the level of the intended distal end of the stent graft) of the SIDR was significantly higher than that of the non-SIDR (192.7 ± 54.9% vs 131.9 ± 10.4%; P ＜ .05). The follow-up mismatch rate of the SIDR was significantly higher than that of the non-SIDR (145.4 ± 34.6 vs 120.3 ± 16.1; P ＜ .05). Compared with the standard TEVAR, TEVAR + RBS was associated with a lower incidence of SIDR (0% vs 2.9%; P = .033) and less secondary intervention (3.9% vs 9.3%; P = .040). Placement of the RBS significantly expanded the true lumen at the level of the descending aorta with the narrowest true lumen and at the level of the distal end of the stent graft. CONCLUSIONS The mismatch between the distal diameter of the stent graft and the diameter of the compressed true lumen seems to be the major factor in the occurrence of SIDR. Placement of an RBS, as an adjunctive technique to TEVAR, could reduce the incidence of SIDR. On the basis of early- to midterm observations, RBSs may improve morphological remodeling of the dissected aorta at certain levels.

Aortorenal Bypass with Autologous Saphenous Vein in Takayasu Arteritis-induced Renal Artery Stenosis

PURPOSE To clarify the outcome of aortorenal bypass (ARB) in Takayasu arteritis-induced renal artery stenosis (TARAS). METHODS A retrospective chart review was conducted on thirty-three consecutive patients (24 females; mean age, 25 years) with TARAS, who underwent ARB with autologous saphenous vein graft. The effects on blood pressure and renal function were analyzed. Primary, primary assisted, and secondary patency rates were counted. The effects of various factors on primary patency rate were analyzed. RESULTS All patients showed severe hypertension (mean BP, 175 ± 26/100 ± 19 mm Hg; mean anti-hypertensive dosage, 2.1 ± 0.6 DDD). Mean estimated glomerular filtration rate was 78 ± 5.1 ml/min. One patient was dialysis-dependent, and three patients had congestive heart failure secondary to left-ventricular dysfunction. ARB was performed for the 39 renal arteries, including 27 unilateral and 6 bilateral bypasses. Postoperative morbidity was 15%. All patients survived. During follow-up (mean, 56 months), two graft occlusions and four graft restenosis occurred. All graft restenosis were eliminated successfully with percutaneous angioplasty, but one patient experienced restenosis again six months later. At 1, 3, and 5 years of follow-up, primary patency was 92%, 89%, and 79%, respectively; primary assisted patency was 95%, 95%, and 91%, respectively; and secondary patency was 95%, 95%, and 91%, respectively. ARB resulted in a decrease in mean BP to 139 ± 15/85 ± 13 mm Hg at one month (P < .05) and 136 ± 19/80 ± 8 mm Hg at last follow-up (P < .05). Mean anti-hypertensive dosage decreased to 1.4 ± 0.8 DDD at one month (P < .05) and 0.6 ± 0.8 DDD at last follow-up (P < .05). Mean estimated glomerular filtration rate increased to 82 ± 4.7 ml/min (P > .05) at one month and 91 ± 4.1 ml/min (P < .05) at last follow-up. The dialysis-dependent patient no longer required haemodialysis, and congestive heart failure resolved in all three patients. CONCLUSIONS Our data suggest that ARB with autologous saphenous vein graft is safe, effective and durable in treating TARAS.

Endovascular therapy for long-segment atherosclerotic aortoiliac occlusion.

OBJECTIVE This retrospective nonrandomized study investigated the outcomes of endovascular therapy for long-segment atherosclerotic aortoiliac occlusion. METHODS From May 2008 to January 2013, 20 patients (one woman and 19 men; mean age, 66.1 years; range, 43-89 years) underwent stent implantation, with or without catheter-directed thrombolysis (CDT), for long-segment aortoiliac occlusion (>10 mm). RESULTS The technical success rate was 95% (19 of 20). No in-hospital mortality was recorded. Aortic thrombus was successfully eliminated with CDT in four patients before percutaneous transluminal angioplasty (PTA) and stenting. Retroperitoneal hemorrhage occurred in one patient, who refused further endovascular surgery. Another 15 patients were treated with PTA and stenting. Postoperative ankle-brachial indexes increased significantly from preoperative values (P < .05). Seventeen patients showed clinical improvement from baseline by an average of 2.5 Rutherford categories. The mean follow-up interval was 17.6 months (range, 4-39 months). The primary patency rates were 93.3% ± 6.4% at 6 months, 83% ± 11.3% at 18 months, and 66.4% ± 17.4% at 24 months. CONCLUSIONS Through brachial and femoral artery puncture, PTA, stenting, and CDT, endovascular therapy is feasible for complete long-segment infrarenal aortic occlusion, with lower complication rates and favorable midterm patency.