Lianjun Huang

The chimney technique for preserving the left subclavian artery in thoracic endovascular aortic repair.

OBJECTIVES The objective of the present study was to evaluate short- and mid-term outcomes of the left subclavian artery (LSA) chimney stent implantation (LSACSI) during thoracic endovascular aortic repair (TEVAR), and to summarize our experience with this technique. METHODS From June 2010 to September 2012, 59 patients (49 men; mean age of 57.4 ± 13.3 years, range from 26 to 83 years) who underwent TEVAR and LSACSI were enrolled. Patients suffered from Stanford type B aortic dissection (n = 27), penetrating aortic ulcer (n = 18), aortic arch aneurysm (n = 9), pseudoaneurysm of the aortic arch (n = 4) and proximal type I endoleak after TEVAR of aortic dissection (n = 1). Elective settings were performed in 72% and emergent in 38% of all patients. Follow-up was performed at postoperative 3 months, 6 months and yearly thereafter. RESULTS The technical success rate was 98.3% (58/59), and 69 thoracic stent grafts were used. Sixty-two chimney stents, including 55 uncovered and 7 covered stents, were implanted in 59 LSAs. The overall immediate endoleak rate was 15.3% (9/59); type I endoleak was observed in 5 patients and type II in 4 patients. The difference in the immediate endoleak rate related to the anatomy between the outer and the inner curvature was statistically significant (35 vs 4%, P = 0.018). Chimney stent compression was observed in 3 patients and another stent was deployed inside the first one. Perioperative complications included stroke (3.4%, 2/59) and left upper limb ischaemia (1.7%, 1/59). The median follow-up period was 16.5 (range 1-39 months). The mortality rate during follow-up was 5.4% (3/56). Complications during follow-up included endoleak [overall, n = 8 (14.3%, 8/56); type I, n = 5; type II, n = 3], retrograde type A aortic dissection (n = 1), collapse (n = 3, 5.4%) or occlusion (n = 2, 3.6%) of the chimney stent. CONCLUSIONS Short- and mid-term results showed that it is feasible to preserve the patency of the LSA in TEVAR with the chimney technique for thoracic aortic pathologies close to the LSA. However, TEVAR combined with LSACSI was not advocated for lesions located at the outer curve of the aortic arch due to a high possibility of endoleak.

Endovascular repair of Stanford B aortic dissection using two stent grafts with different sizes.

OBJECTIVE The objective of this study was to introduce a novel strategy for thoracic endovascular aortic repair of Stanford B aortic dissection using two-stent graft implantation (TSI), in which the proximal stent and distal stent with different sizes are sequentially deployed, and to summarize our experience with this technique. METHODS A retrospective study was conducted of 72 consecutive patients (61 men; mean age, 55 ± 7 years; range, 41-67 years) with Stanford type B aortic dissection who underwent TSI treatment between January 2012 and May 2013. Among all patients, 43 (59.7%) involved the infrarenal aorta and 29 (40.3%) involved the whole thoracic and abdominal aorta; mean aortic involvement length was 226 ± 13 mm (range, 182-312 mm). Eight cases were for acute dissection (within 2 weeks from onset of symptoms), 11 cases were for chronic dissection (>3 months after initial dissection), and 53 cases were for subacute dissection (between 2 weeks and 3 months). Twenty-two cases (30.6%) were uncomplicated type and 50 cases (69.4%) were complicated type. Follow-up was performed postoperatively at 1 month, 6 months, and yearly thereafter. Technique success, aorta morphology, and procedure-related complications were evaluated. RESULTS Technical success was achieved in 100%; 72 pairs of stent grafts (144 thoracic stent grafts) and 10 left subclavian artery chimney stents were used. The mean aortic length coverage by the stent grafts was 197.6 ± 20.3 mm, and mean taper diameter span was 7.5 ± 1.8 mm. All patients were followed up from 6 to 16 months (mean, 10 ± 4 months); 95.8% (69 of 72) had a thrombosed false lumen in the aortic coverage, and the true lumen expanded on average 57% ± 11% (23%-100%). No significant changes were found in aortic diameters of the proximal and distal ends of the two stent grafts and the angles between centerlines of the distal end of the stent and the aorta during follow-up. Procedure-related complications included transient paraplegia (coverage of the left subclavian artery without revascularization and extensive coverage of aorta >220 mm) due to acute spinal cord ischemia (n = 1) and malapposition of the distal stent (primary tear closed, true lumen expansion led to oversize rate insufficient in distal stent diameter; n = 1). No death or malperfusion complications were observed during the perioperative period and follow-up. CONCLUSIONS Short-term outcomes showed TSI to be a flexible and effective approach to accurately repair Stanford B aortic dissection that could potentially address the limitations of currently available stent grafts. Further prospective clinical studies are warranted to evaluate its long-term efficacy.

Risk factors for distal stent graft-induced new entry following endovascular repair of type B aortic dissection.

BACKGROUND Distal stent graft-induced new entry (DSINE) has been increasingly observed following thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). We seek to identify the risk factors for DSINE following TEVAR in patients with TBAD. METHODS Between January 2009 and January 2013, we performed TEVAR for 579 patients with TBAD. The clinical data were retrospectively analyzed with univariate and multivariate analyses to identify the risk factors for DSINE. RESULTS Two patients (0.3%) died after the initial TEVAR. Morbidity included spinal cord injury in 2 (0.3%), stroke in 3 (0.5%) and endoleak in 12 (2.1%) patients. Clinical and radiological follow-up was complete in 100% (577/577) averaging 47±16 months. Late death occurred in 6 patients. DSINE occurred in 39 patients (6.7%) at mean 22±17 months after the initial TEVAR, which was managed with re-TEVAR in 25 and medically in 14. At 33±18 months after DSINE, 11 of patients managed medically (11/14) and all patients managed with re-TEVAR (25/25) survived (P=0.048). Freedom from DSINE was 92.7% at 5 years (95% CI: 90.0-94.7%). Using tapered stent grafts with a proximal end 4-8 mm larger than the distal end, TEVAR performed in the acute phase (≤14 days from onset) was associated with a significantly lower incidence of DSINE than TEVAR performed in the chronic phase (4.3%, 7/185 vs. 13.9%, 15/108; P=0.003). Risk factors for DSINE were stent grafts less than 145 mm in length [odds ratio (OR) 2.268; 95% CI: 1.121-4.587; P=0.023] and TEVAR performed in the chronic phase (OR 1.935; 95% CI: 1.004-3.731; P=0.049). CONCLUSIONS Our results show that TEVAR performed during the acute phase and using stent grafts longer than 145 mm could decrease the incidence of DSINE in patients with TBAD. Tapered stent grafts with a proximal end 4-8 mm larger than the distal end may be helpful in preventing DSINE after TEVAR performed in the acute phase than TEVAR performed in the chronic phase, due to the difference in mobility of the dissected flap. Expedite repeat TEVAR is recommended to improve the clinical prognosis for patients with DSINE.

Magnitude of Soluble ST2 as a Novel Biomarker for Acute Aortic Dissection

Background: Misdiagnosis of acute aortic dissection (AAD) can lead to significant morbidity and death. Soluble ST2 (sST2) is a cardiovascular injury–related biomarker. The extent to which sST2 is elevated in AAD and whether sST2 can discriminate AAD from other causes of sudden-onset severe chest pain are unknown. Methods: We measured plasma concentrations of sST2 (R&D Systems assay) in 1360 patients, including 1027 participants in the retrospective discovery set and 333 patients with initial suspicion of AAD enrolled in the prospective validation cohort. Measures of discrimination for differentiating AAD from other causes of chest pain were calculated. Results: In the acute phase, sST2 levels were higher in patients with AAD than those with either acute myocardial infarction in the first case-control discovery set within 24 hours of symptom onset or with patients with pulmonary embolism in the second discovery set (medians of 129.2 ng/mL versus 14.7 with P<0.001 for AAD versus acute myocardial infarction and 88.6 versus 9.3 with P<0.001 for AAD versus pulmonary embolism). In the prospective validation set, sST2 was most elevated in patients with AAD (median [25th, 75th percentile]: 76.4 [49.6, 130.3]) and modestly elevated in acute myocardial infarction (25.0 [15.5, 37.2]), pulmonary embolism (14.9 [10.2, 30.1]), and angina patients (21.5 [13.1, 27.6], all P<0.001 versus AAD). The area under receiver operating characteristic curve for patients with AAD versus all control patients within 24 hours of presenting at the emergency department was 0.97 (0.95, 0.98) for sST2, 0.91 (0.88, 0.94) for D-dimer, and 0.50 (0.44, 0.56) for cardiac troponin I, respectively. At a cutoff level of 34.6 ng/mL, sST2 had a sensitivity of 99.1%, specificity of 84.9%, positive predictive value of 68.7%, negative predictive value of 99.7%, positive likelihood ratio of 6.6, and negative likelihood ratio of 0.01. Conclusions: Among patients with suspected aortic dissection in the emergency department, sST2 showed superior overall diagnostic performance to D-dimer or cardiac troponin I. Additional study is needed to determine whether sST2 might be a useful rule-out marker for AAD in the emergency room.

Single-center experience with simultaneous thoracic endovascular aortic repair and abdominal endovascular aneurysm repair.

Objective To evaluate the efficacy and outcomes of simultaneous thoracic endovascular aortic repair (TEVAR) and abdominal endovascular aneurysm repair (EVAR). Methods A total of 21 patients (20 men; mean 65 ± 7 years, range 54–77) underwent simultaneous TEVAR and EVAR between September 2010 and June 2015 at a single center were retrospectively reviewed. All patients had concomitant thoracic pathologies (aneurysm, penetrating aortic ulcer, intramural hematoma, or dissection) and abdominal aortic aneurysm. The abdominal aneurysms diameters ranged from 5.9 cm to 10 cm. Thoracic lesions in 17 patients were complicated with acute aortic syndrome, and the remainders had indications for simultaneous repair. All patients were followed up postoperative at 1 month, 6 months, and yearly thereafter. Technique success, procedure-related complications were evaluated. Results All patients received local anesthesia, perioperative relative high arterial pressure (above 130/80 mmHg) maintenance, and prophylactic high-dose corticosteroid. The technical success rate was 100%. Average procedural time was 157.6 ± 45.6 min. The length of thoracic coverage was 20.4 ± 4.7 cm (range 15–27). Two patients required left subclavian artery coverage during TEVAR and two patients required lowest renal artery coverage during EVAR. Chimney stents were deployed simultaneously. Patients were followed between 2 and 59 months postoperatively. No patients developed acute cardiopulmonary complications and contrast-induced nephropathy. Two patients developed transient lower extremity weakness that resolved with blood pressure elevation, cerebrospinal fluid drainage, and intravenous drips of high-dose corticosteroid. The average hospital stay was 10.7 ± 7.9 days (range 4–30). During follow-up, one patient died of aneurysm rupture at postoperative 6 months, two patients developed type Ib endoleak at 9 months and 48 months respectively, one was successfully sealed with iliac stent-graft extension, the other received conservative treatment and is symptom free till now. Conclusion Combined TEVAR and EVAR can be performed safely with minimal morbidity and mortality. When anatomically feasible, simultaneous TEVAR and EVAR can be considered as an acceptable alternative for multilevel aortic diseases.

Endovascular Repair for Thoracic Aortic False Aneurysms: Single-Center Experience in 102 Patients

BACKGROUND Thoracic aortic false aneurysm is unusual and experience with endovascular repair is limited. We evaluate the efficacy of endovascular repair in patients with thoracic aortic false aneurysms. METHODS The early and midterm outcomes of endovascular repair in 102 patients with thoracic aortic false aneurysms were analyzed. RESULTS There were 80 men and 22 women (age 54.9 ± 13.7 years). Emergent or urgent endovascular repair was done in 19 cases (18.6%) and elective in 83 (81.4%). Procedure was successful in 99.0%. Early death occurred in 4 patients (3.9%). No early death occurred in elective patients. Early complications occurred in 7 patients (6.9%). Follow-up was complete in 100% for 24.0 ± 18.5 months (range, 1.5 to 67.3). Fourteen late deaths occurred (13.7%). Late events occurred in 9 patients (8.8%). Survival at 6 month, 1 year and 3 years was 90.7%, 86.7% and 84.5%, respectively. CONCLUSIONS Satisfactory early and midterm outcomes have been achieved with endovascular repair in this series. Although emergent or urgent patients had higher rates of early mortality and morbidity, the majority of them achieved stable late survival as long as they survived at least 6 months. These results argue favorably for use of endovascular repair in the management of patients with thoracic aortic false aneurysms.

One-stage hybrid procedure without sternotomy for treating thoracic aortic pathologies that involve distal aortic arch: a single-center preliminary study

OBJECTIVE This study aims to evaluate the initial results of a hybrid procedure without sternotomy for treating descending thoracic aortic disease that involves distal aortic arch. It also intends to report our initial experience in performing this procedure. METHODS A total of 45 patients (35 males and 10 females) with descending thoracic aortic disease underwent a hybrid procedure, namely, thoracic endovascular aortic repair (TEVAR) combined with supra-arch branch vessel bypass, in our center from April 2009 to August 2014. Right axillary artery to left axillary artery bypass (n=20) or right axillary artery to left common carotid artery (LCCA) and left axillary artery bypass (n=25) were performed. The conditions of all patients were followed up from the 2(nd) month to the 65(th) month postoperative (mean, 26.0±17.1). Mortality within 30 days, complications such as endoleak after the hybrid procedure, and stenosis or blockage of the bypass graft during the follow-up period was assessed. RESULTS All the patients underwent a one-stage procedure. One case of death and one case of cerebral infarction were reported within 30 days. One patient died of the sudden drop in blood pressure during the 2(nd) day of operation. Meanwhile, another patient suffered from cerebral infarction. Two patients underwent open surgery, and one of them had to undergo a second TEVAR during the follow-up period. Moreover, endoleak occurred in two patients and a newly formed intimal tear was observed in one patient. Overall, 93.2% of the patients survived without any complication related to the hybrid procedure. CONCLUSIONS Initial results suggest that the one-stage hybrid procedure is a suitable therapeutic option for thoracic aortic pathologies that involve distal aortic arch. However, this procedure is not recommended for type-B aortic dissection, in which a tear is located in the greater curvature or near the left subclavian artery (LSA), because of the high possibility of endoleak occurrence.

Endovascular repair of residual intimal tear or distal new entry after frozen elephant trunk for type A aortic dissection

BACKGROUND In patients with type A dissection, residual dissection and new distal entry tears following the frozen elephant trunk (FET) procedure adversely affect long-term prognosis. Management include open and endovascular repair, while clinical experience is limited. We evaluate the efficacy of thoracic endovascular aortic repair (TEVAR) in management of residual intimal tear or distal new entry tear following FET in patients with type A aortic dissection (TAAD). METHODS Between May 2003 and April 2013, we performed FET and total arch replacement for 1,003 patients with TAAD. Among these, 23 patients (2.3%) required TEVAR for distal new entry (n=2) or residual intimal tear (n=21) at a mean of 2.0±1.6 years after FET. Mean age was 50.1±11.5 years. Marfan syndrome was seen in 2 patients (8.7%). RESULTS Procedural success was 100%. The distal landing zone was above the 11th thoracic vertebra (T11) in 86.9% (20/23). Neither death nor any paraplegia or stroke occurred early after TEVAR. Follow-up was complete in 100% averaging 2.8±1.7 years (0.3-6.4). One non-Marfan patient died of distal aortic rupture at 4 months after TEVAR. No late stroke or paraplegia occurred. Survival was 95.7% (95% CI, 72.9-99.4%) at 3 and 5 years, respectively. CTA detected false lumen obliteration by thrombus around the endograft in the descending aorta in 91.3% (21/23) of patients. CONCLUSIONS These early and midterm outcomes show the efficacy of TEVAR in obliterating the residual intimal tear or distal new entry after FET in patients with TAAD. TEVAR may be an alternative approach to distal new entry or residual intimal tear following FET for patients with TAAD.

Regarding “Late aortic remodeling persists in the stented segment after endovascular repair of acute complicated type B aortic dissection”

Conrad et al reported excellent long-term aortic remodeling after thoracic endovascular aortic repair of type B dissection. Importantly, they showed expansion of the true lumen and reduction of the false lumen in the stented thoracic aorta over time but persistent expansion in the uncovered dissected aorta. However, their report is not clear about the predictors of positive remodeling and whether the extending bare-metal stents (although only used in 10% patients) promote this process. In addition, aneurysmal degeneration requiring reintervention occurred in one patient distal to the stent graft, but its cause was not discussed. How to prevent distal stent-related complication remains a question in the longer term. Endovascular therapy relies on covering the primary entry tear to initiate false lumen thrombosis, expand the true lumen, and stimulate aortic remodeling. Factors such as dissection extending to the visceral arteries and multiple or large distal intimal tears may negatively affect aortic remodeling. Lombardi et al found that patients with more descending aorta coverage using a distal bare-metal stent were more likely to have complete false lumen thrombosis in the thoracic aorta and abdominal aorta. In their study, however, the distal bare-metal stent was initially available in a set diameter and tubular or small taper configuration; excessive oversize rate of the distal stent and uncovered thoracic distal tears still potentially increase distal stent-related complications, including distal re-entry and aneurysm and pseudoaneurysm formation, and necessitate reintervention. We recently reported two stent graft implantation (TSI) to treat patients with type B dissection, and the distal coveredtapered stent was introduced. Short-term outcomes showed 95.8% (69 of 72) of patients with false lumen thrombosis in the stented segment. The distal tapered stent used in TSI is different from distal bare-metal stent or distal restrictive bare stent. It can really cover the distal tears, as many as possible, and in particular, expand the true lumen without excessive axial force. Furthermore, TSI with the current thoracic stent combined with the new, large tapered stent can obtain an optimal distal landing zone because the total length of the stent grafts can flexibly change with different overlapping extent of two stents. Although patient heterogeneity exists, we believe TSI can provide more accurate repair for patients with type B dissection and improve late aortic remodeling.

Should a Tapered Stent Be Considered in TEVAR of Type B Dissection

To the Editors Dr Havelka and colleagues recently reported 2 rare cases of aortic occlusion and abdominal malperfusion syndrome after intimal intussusception during endovascular repair of acute type B dissection. Fortunately, both of them were converted to open repair in a timely fashion; distal perfusion was stored and early outcomes were favorable. The preoperative imaging clearly showed the wide extent of the intimal flap and the collapse of the true lumen responsible for the malperfusion syndrome. The intussusception had occurred following implantation of 2 thoracic stentgrafts deployed during thoracic endovascular aortic repair (TEVAR). The authors indicated that excessive stent-graft manipulation in the first case and balloon dilation in the second case led to the complications. However, excessive stent axial force induced by the large stent-grafts seemed to be the main cause. The proximal oversizing reached 13.3% and 21.4%, respectively, and the distal oversizing could have been even greater, though no data regarding the distal true lumen diameter (other than entire aorta) were provided. Notably absent in these cases with collapsed true lumens was mention of the distal landing zone and the possibility of extended stenting after proximal stent-graft deployment. TEVAR has been the first-line treatment for complicated type B dissection, with minimal mortality and morbidity. Mismatch between the current stent-graft and dissected aorta is the major cause of stent-graft–related complications, including new entries, retrograde dissection, and even intimal flap detachment. The dissected aorta displays obvious tapering of the true lumen downstream. Tapered stent-grafts have satisfactory compliance with the diseased aorta and reduce stent axial force to the aortic wall, thus potentially decreasing the risk of stent-related complications such as the intimal flap detachment in the reported cases. Moreover, the distal stent-graft should terminate at a point in the true lumen with more normal aortic wall in order to obtain a stable distal landing site. The sleeve-like true lumen shown in the first of Havelka’s cases failed to provide a stable distal landing zone. In our work, we consider an optimal distal landing zone one that ensures coverage of multiple thoracic intimal tears and is located in a straight portion of the descending aorta, terminating in near normal aortic wall. We reported our favorable outcomes with endovascular repair for type B dissection using 2 stent-grafts of different sizes. In our study, a tapered covered stent (Grikin, Beijing, China) was deployed in a carefully selected distal landing zone below a conventional tubular thoracic stent-graft. The distal tapered stent is different from a distal bare metal or restrictive bare stent. It can help cover as many of the distal tears as possible and, in particular, expand the true lumen without excessive axial force. Furthermore, the distal tapered covered stent can reach an optimal distal landing zone by adjusting the overlap between 2 thoracic tubular stent-grafts above it. Although patient anatomy varies, we believe a current thoracic stent-graft plus a distal tapered covered stent can provide more compatible repair for type B dissection and reduce stent-graft–related complications.