Mario Lachat

Collected world and single center experience with endovascular treatment of ruptured abdominal aortic aneurysms

Background:Case and single center reports have documented the feasibility and suggested the effectiveness of endovascular aneurysm repair (EVAR) of ruptured abdominal aortic aneurysms (RAAAs), but the role and value of such treatment remain controversial. Objective:To clarify these we examined a collected experience with use of EVAR for RAAA treatment from 49 centers. Methods:Data were obtained by questionnaires from these centers, updated from 13 centers committed to EVAR treatment whenever possible and included treatment details from a single center and information on 1037 patients treated by EVAR and 763 patients treated by open repair (OR). Results:Overall 30-day mortality after EVAR in 1037 patients was 21.2%. Centers performing EVAR for RAAAs whenever possible did so in 28% to 79% (mean 49.1%) of their patients, had a 30-day mortality of 19.7% (range: 0%–32%) for 680 EVAR patients and 36.3% (range: 8%–53%) for 763 OR patients (P < 0.0001). Supraceliac aortic balloon control was obtained in 19.1% ± 12.0% (±SD) of 680 EVAR patients. Abdominal compartment syndrome was treated by some form of decompression in 12.2% ± 8.3% (±SD) of these EVAR patients. Conclusion:These results indicate that EVAR has a lower procedural mortality at 30 days than OR in at least some patients and that EVAR is better than OR for treating RAAA patients provided they have favorable anatomy; adequate skills, facilities, and protocols are available; and optimal strategies, techniques, and adjuncts are employed.

Endoleaks after endovascular abdominal aortic aneurysm repair: detection with dual-energy dual-source CT.

PURPOSE To assess the diagnostic performance of dual-energy dual-source computed tomography (CT) in the detection of endoleaks after endovascular abdominal aortic aneurysm (AAA) repair. MATERIALS AND METHODS This study was local ethics board approved, and written informed consent was obtained from all patients. One hundred eighteen patients (21 women, 97 men; mean age, 74 years +/- 8 [standard deviation]) underwent follow-up dual-energy dual-source CT during the nonenhanced, arterial, and delayed phases after AAA repair. Delayed phase CT images were acquired in the dual-energy mode for reconstruction of virtual nonenhanced images. Two blinded and independent readers evaluated the data for the presence or absence of endoleaks during three reading sessions: Standard nonenhanced, arterial phase, and delayed phase images were read during session A; virtual nonenhanced, arterial phase, and delayed phase images, during session B; and virtual nonenhanced and delayed phase images, during session C. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated, with the session A image data set as the reference standard. Radiation dose parameters were estimated. RESULTS Reading session A revealed that 52 (44%) of 118 patients had endoleaks. Overall sensitivity, specificity, NPV, and PPV for CT endoleak detection during sessions B and C were identical: 100%, 97%, 100%, and 96%, respectively. The accuracy of the session B and session C readings was not significantly different from that of the session A reading (P = .50). The effective radiation dose in the image acquisition protocol involving one dual-energy scan was significantly (P < .001) lower than the effective doses in the protocols involving standard triple-phase scanning (mean difference, 61%) and standard nonenhanced and delayed phase scanning (mean difference, 41%). CONCLUSION Compared with standard protocols, one dual-energy dual-source CT scan performed during the delayed phase with reconstruction of virtual nonenhanced images enables detection of endoleaks after endovascular AAA repair with high accuracy and a considerably lower radiation dose.

Functional Growth in Tissue-Engineered Living, Vascular Grafts Follow-Up at 100 Weeks in a Large Animal Model

Background— Living autologous vascular grafts with the capacity for regeneration and growth may overcome the limitations of contemporary artificial prostheses. Particularly in congenital cardiovascular surgery, there is an unmet medical need for growing replacement materials. Here we investigate growth capacity of tissue-engineered living pulmonary arteries in a growing lamb model. Methods and Results— Vascular grafts fabricated from biodegradable scaffolds (ID 18±l mm) were sequentially seeded with vascular cells. The seeded constructs were grown in vitro for 21days using biomimetic conditions. Thereafter, these tissue-engineered vascular grafts (TEVGs) were surgically implanted as main pulmonary artery replacements in 14 lambs using cardiopulmonary bypass and followed up for ≤100 weeks. The animals more than doubled their body weight during the 2-year period. The TEVG showed good functional performance demonstrated by regular echocardiography at 20, 50, 80, and 100 weeks and computed tomography–angiography. In particular, there was no evidence of thrombus, calcification, stenosis, suture dehiscence, or aneurysm. There was a significant increase in diameter by 30% and length by 45%. Histology showed tissue formation reminiscent of native artery. Biochemical analysis revealed cellularity and proteoglycans and increased collagen contents in all of the groups, analogous to those of native vessels. The mechanical profiles of the TEVG showed stronger but less elastic tissue properties than native pulmonary arteries. Conclusions— This study provides evidence of growth in living, functional pulmonary arteries engineered from vascular cells in a full growth animal model.

Differential Effects of 17β-Estradiol on Function and Expression of Estrogen Receptor α, Estrogen Receptor β, and GPR30 in Arteries and Veins of Patients With Atherosclerosis

Venous complications have been implicated in the adverse effects of hormone replacement therapy. This study investigated acute effects of the natural estrogen, 17&bgr;-estradiol, on function, estrogen receptors/GPR30 expression, and kinase activation in vascular rings and cultured smooth muscle cells from arteries and veins of patients with coronary artery disease. Changes in vascular tone of internal mammary arteries and saphenous veins exposed to the steroid were recorded. 17&bgr;-Estradiol caused concentration-dependent, endothelium-independent relaxation in arteries (P<0.05 versus solvent control) but not in veins (P not significant). 17&bgr;-Estradiol enhanced contractions to endothelin-1 in veins but not in arteries. The novel membrane estrogen receptor GPR30 was detected in both vessels. Moreover, gene expression of estrogen receptor &bgr; was 10-fold higher than that of estrogen receptor &agr; or GPR30 (P<0.05). Expression of all 3 of the receptors was reduced after exposure to 17&bgr;-estradiol in arteries but not in veins (P<0.05). Basal phosphorylation levels of extracellular signal-regulated kinase were higher in venous than in arterial smooth muscle cells and were increased by 17&bgr;-estradiol in arterial cells only. In summary, this is the first study to report that, in human arteries but not in veins, 17&bgr;-estradiol acutely affects vascular tone, estrogen receptor expression, including GPR30, and extracellular signal-regulated kinase phosphorylation. These data indicate that effects of natural estrogens in humans differ between arterial and venous vascular beds, which may contribute to the vascular risks associated with menopause or hormone therapy.

Acute traumatic aortic rupture: early stent-graft repair

OBJECTIVE Prospective evaluation of early stent-graft repair of acute traumatic aortic rupture. METHODS Twelve patients with acute traumatic aortic rupture of the descending aorta, out of a series of 337 endovascular aortic procedures, were treated by implantation of self-expanding stent-grafts. The procedures were performed within a mean post-injury time-period of 5+/-7 days (median: 1 day). The feasibility of stent-grafting was assessed by CT scanning and echography. Implantation was performed under local (n=6), or general anesthesia (n=6) if patients were already intubated (n=5) or required a common iliac artery access (n=1). RESULTS The immediate technical success rate was 100%. There were no post-procedure complications in all but one patient, who died 12 h postoperatively (8% mortality). Complete sealing of the aortic rupture in the remaining 11 patients was confirmed by postoperative CT scans. There were no intervention-related morbidity or mortality during the mean follow-up of 17 months. One patient with peri-graft leakage was successfully repaired with an additional stent-graft 12 months postoperatively. CONCLUSION Non-delayed or early stent-grafting in acute traumatic rupture of the descending aorta is feasible. This technique seems to be a valuable option, in particular when associated lesions may interfere with the surgical outcome. Immediate post-procedural CT scanning and/or echography should be performed, in order to rule out residual leakage.

10 years of emergency endovascular aneurysm repair for ruptured abdominal aortoiliac aneurysms: lessons learned.

Objective:To evaluate a single centers 10-year experience with emergency endovascular aneurysm repair (eEVAR) in 102 patients with ruptured abdominal aortoiliac aneurysms (RAAA). Methods:Data from 102 patients (mean age, 73 ± 9 years) with RAAA treated by eEVAR from January 1998 to April 2008 were retrospectively reviewed. From January 2000, all patients were treated according to an intention-to-treat protocol. The only exclusion criterion was unsuitable anatomy. 31/102 patients had moderate shock and 14/102 patients had severe shock with a systolic blood pressure <70 mm Hg or <50 mm Hg, respectively. 71/102 procedures were carried out under local anesthesia. Endograft types used were mainly bifurcated (92/102). Open abdomen treatment (OAT) because of abdominal compartment syndrome (ACS) was used when signs of organ failure occurred and/or bladder pressure rose >20 mm Hg. Results:The 30-day mortality for eEVAR was 13% (13/102). Technical success (defined as successful deployment of the endograft, absence of extravasation in the postprocedural contrast enhanced CT scan and hemodynamic stabilization) was 99% (101/102). Nineteen unstable patients (19%) required transfemoral supraceliac aortic balloon occlusion. ACS was detected and treated by OAT in 20 patients (20%). 16 type I, 26 type II and 1 type III endoleaks were detected on postoperative CT examination. Two patients had a combined type I and II endoleak. 11 patients were retreated for immediate correction of 10 type I and 2 type II endoleaks. 6 type I and 1 type III low-flow endoleaks were observed and resolved spontaneously within 30 days. Major 30-day morbidity was 35%. Conclusion:In this 102 patient contemporary series of eEVAR for RAAA, endografting proved to be safe with a 30-day mortality of 13%. Key components of this favorable outcome result were adequate preoperative diagnostic imaging, hypotensive hemostasis, selective transfemoral supraceliac aortic balloon occlusion, predominantly local anesthesia, detection and treatment of ACS, and attention to logistics. Widespread adoption of these treatment components is recommended.

Use of covered chimney stents for pararenal aortic pathologies is safe and feasible with excellent patency and low incidence of endoleaks.

BACKGROUND To present the clinical experience of consecutive series with use of balloon-expandable and self-expanding chimney endografts (balloon-expandable covered stent group [BECS] vs self-expanding covered stent group [SECS]) in the endovascular treatment of challenging aortic pathologies requiring renal and/or visceral revascularization. METHODS Between January 2009 and May 2011, data for 37 high-risk patients from one center and 35 patients from another institution, with pararenal aortic pathologies treated by the chimney endovascular technique, were prospectively collected. The chimney-graft technique is based on the deployment of a covered or bare-metal stent parallel to the aortic endograft, thereby creating a conduit that runs outside the aortic main endograft, and has been proposed to ensure secure proximal fixation extending the sealing zones. RESULTS Forty-six consecutive target vessels (43 renal arteries and 3 superior mesenteric arteries) were revascularized by the Advanta (Atrium, Hudson, NH) BECS (1.2 chimneys/patient); in contrast, 81 consecutive target vessels (64 renal arteries, 11 superior mesenteric arteries, and 6 celiac trunks) were revascularized by the Viabahn (Gore, Flagstaff, Ariz) SECS (2.3 chimneys/patient). The success rate for target vessel preservation was 97.8% for the BECS group and 100% for the SECS group in the entire follow up. There was one symptomatic left renal artery occlusion of the BECS group treated by open thrombectomy of the left renal artery and placement of 8-mm Dacron (BBraun, Aesculap AG, Tuttlingen, Germany) iliorenal bypass. Additionally, one patient underwent repeat balloon angioplasty with a 5-mm balloon due to high-grade in-stent stenosis of a 6 × 59 Advanta stent graft 12 months postoperatively. Overall, one perioperative (and not present in the computed tomography angiography at discharge) type Ia endoleak was detected in the BECS group. In contrast, five perioperative type Ia endoleaks were present in the SECS group; however, only one of them was persistent in the radiological imaging and was treated by proximal extension of a 5-mm cuff, 1 year postoperatively, due to continuous aneurismal sac increase. No patient of any subgroup developed postoperative persistent renal insufficiency with need of hemodialysis. Thirty-day and during the follow-up procedure-related mortality was 0% for both BECS and SECS groups. CONCLUSIONS In summary, midterm results of use of covered chimney stents for pararenal aortic pathologies show safety and feasibility with excellent patency and low incidence of endoleaks.

HMG-CoA reductase inhibition improves endothelial cell function and inhibits smooth muscle cell proliferation in human saphenous veins ☆

OBJECTIVES This study examined effects of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase inhibitor cerivastatin on human saphenous vein (SV), endothelial cells (EC) and smooth muscle cells (SMC). BACKGROUND Venous bypass graft failure involves EC dysfunction and SMC proliferation. Substances that improve EC function and inhibit SMC proliferation would be of clinical relevance. METHODS Both EC and SMC were isolated from SV. Endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) production were analyzed by immunoblotting and porphyrinic microsensor. The SMC proliferation was assayed by 3H-thymidine incorporation. Protein kinases and cell cycle regulators were analyzed by immunoblotting. RESULTS Cerivastatin (10(-9) to 10(-6) mol/liter) enhanced eNOS protein expression and NO release (about two-fold) in EC in response to Ca2+ ionophore (10(-6) mol/liter). This was fully abrogated by the HMG-CoA product mevanolate (2 x 10(-4) mol/liter). In SMC, platelet-derived growth factor (5 ng/ml) enhanced 3H-thymidine incorporation (298 +/- 23%, n = 4), activated cyclin-dependent kinase (Cdk2), phosphorylated Rb and down-regulated p27Kip1 (but not p21CiP1). Cerivastatin reduced the 3H-thymidine incorporation (164 +/- 11%, p < 0.01), inhibited Cdk2 activation and Rb phosphorylation, but did not prevent p27Kip1 down-regulation, nor p42mapk and p70S6K activation. Mevalonate abrogated the effects of cerivastatin on Cdk2 and Rb but only partially rescued the 3H-thymidine incorporation (from 164 +/- 11% to 211 +/- 13%, n = 4, p < 0.01). CONCLUSIONS In humans, SVEC inhibition of HMG-CoA/mevalonate pathway contributes to the enhanced eNOS expression and NO release by cerivastatin, whereas in SMC, inhibition of this pathway only partially explains cerivastatin-induced cell growth arrest. Inhibition of mechanisms other than p42mapk and p70S6K or Cdk2 are also involved. These effects of cerivastatin could be important in treating venous bypass graft disease.

Collected world experience about the performance of the snorkel/chimney endovascular technique in the treatment of complex aortic pathologies: the PERICLES registry.

OBJECTIVES We sought to analyze the collected worldwide experience with use of snorkel/chimney endovascular aneurysm repair (EVAR) for complex abdominal aneurysm treatment. BACKGROUND EVAR has largely replaced open surgery worldwide for anatomically suitable aortic aneurysms. Lack of availability of fenestrated and branched devices has encouraged an alternative strategy utilizing parallel or snorkel/chimney grafts (ch-EVAR). METHODS Clinical and radiographic information was retrospectively reviewed and analyzed on 517 patients treated by ch-EVAR from 2008 from 2014 by prearranged defined and documented protocols. RESULTS A total of 119 patients in US centers and 398 in European centers were treated during the study period. US centers preferentially used Zenith stent-grafts (54.2%) and European centers Endurant stent-grafts (62.2%) for the main body component. Overall 898 chimney grafts (49.2% balloon expandable, 39.6% self-expanding covered stents, and 11.2% balloon expandable bare metal stents) were placed in 692 renal arteries, 156 superior mesenteric arteries (SMA), and 50 celiac arteries. At a mean follow-up of 17.1 months (range: 1-70 months), primary patency was 94%, with secondary patency of 95.3%. Overall survival of patients in this high-risk cohort for open repair at latest follow-up was 79%. CONCLUSIONS This global experience represents the largest series in the ch-EVAR literature and demonstrates comparable outcomes to those in published reports of branched/fenestrated devices, suggesting the appropriateness of broader applicability and the need for continued careful surveillance. These results support ch-EVAR as a valid off-the-shelf and immediately available alternative in the treatment of complex abdominal EVAR and provide impetus for the standardization of these techniques in the future.

Tissue engineering: A new approach in cardiovascular surgery; Seeding of human fibroblasts followed by human endothelial cells on resorbable mesh

OBJECTIVE In tissue engineering the material properties of synthetic compounds are chosen to enable delivery of dissociated cells onto a scaffold in a manner that will result in in vitro formation of a new functional tissue. The seeding of human fibroblasts followed by human endothelial cells on resorbable mesh is a precondition of a successful creation of human tissues such as vessels or cardiac valves. METHODS Polymeric scaffolds (n = 18) composed of polyglycolic acid (PGA) with a fiber diameter of 12-15 microm and a polymer density of 70 mg/ml were used as square sheets of 1 x 1 x 0.3 cm. Fibroblasts (passage 7) harvested from human foreskin were seeded (3.4 x 10(6)) and cultured over a 3 week period on a PGA-mesh, followed by seeding of endothelial cells (passage 5, 2.8 x 10(6)) harvested from human ascending aorta. Thereafter the new tissue was stained for HE, van Gieson, Trichrom Masson, Factor VIII and CD 34 and proved by scanning electron microscopy. RESULTS Microscopic examination of the seeded mesh demonstrated that the human fibroblasts were attached to the polymeric fibers and had begun to spread out and divide. The scanning electron microscopic examination demonstrated a homogeneous scaffold resembling a solid sheet of tissue. The seeded endothelial cells formed a monolayer on the fibroblasts and no endothelial cell invasion or new formation of capillaris could be detected. CONCLUSIONS These results are a first step to demonstrate that seeding of human fibroblasts and endothelial cells on PGA-mesh might be a feasible model to construct human tissues such as vessels or cardiac valves.