Pulse Wave Velocity for Risk Stratification of Patients with Aortic Aneurysm.

Background: Patients with an aortic aneurysm are at high cardiovascular risk. Pulse wave velocity (PWV) is used as a parameter for risk stratification but may be affected by aortic disease (AoD). This study aimed to investigate the dependence of PWV on treated or untreated AoD and to identify modifiable factors of PWV. Methods: The measurement of PWV with the Mobil-O-Graph was performed fully automatically in a collective of 381 patients (75.6% male and 24.4% female). Of all patients, 53.8% had nonaortic atherosclerotic vascular disease (AVD), 28.9% had treated AoD, and 17.3% had untreated AoD. Results: There was a statistically significant effect of age (R2 = 0.838) and current systolic blood pressure (SBP) on PWV (page corrected < 0.05). After correction for age, no statistically significant difference was found between the PWV of men and women, patients with different body weights or degrees of chronic kidney disease, diabetics and nondiabetics, and smokers and nonsmokers. Comparison between patients with nonaortic AVD and treated or untreated AoD revealed no statistically significant differences (PWVnonaortic AVD 10.0 ± 1.8 m/s, PWVtreated AoD 10.0 ± 1.5 m/s, PWVuntreated AoD 9.8 ± 1.6 m/s; page corrected > 0.05). Conclusions: PWV determined with the Mobil-O-Graph correlated with age and current SBP. Neither aortic disease versus nonaortic AVD, its treatment, nor other cardiovascular risk factors had a significant effect on PWV. Successful blood pressure control is crucial to avoid high PWV and thus an increase in cardiovascular events.

[Management of Visceral Artery Aneurysms with Preservation of Organ Perfusion: More Than Twenty Years Experience]. / Management von Viszeralarterienaneurysmen unter besonderer Berücksichtigung der Organperfusion ­ Erfahrungen über mehr als 20 Jahre.

BACKGROUND: Visceral artery aneurysms (VAA) are rare and often incidental findings. Indications for treatment are symptomatic patients, pseudoaneurysms and a true aneurysm of diameter of ≥ 2.5 cm for mesenteric arteries and ≥ 3 cm for renal artery aneurysms. Pregnancy and liver transplantation play an important role in aneurysm rupture. Technical success after open or endovascular procedure and maintenance of organ perfusion are crucial. The aim of this review is to evaluate our data and experience of more than 20 years and to develop a strategy to deal with visceral artery aneurysm in elective and emergency cases. PATIENTS: Between 1995 and 2018, 179 patients (84 males, 95 females, median age 62 [18 - 87] years) were diagnosed with VAA at the Regensburg University Hospital. The site of aneurysm was the splenic artery in 113 (63%) patients (pts), hepatic and renal arteries in 22 and 21 pts (12% each), and gastropancreaticoduodenal artery in 14 (8%) and superior/inferior mesenteric artery in 9 (5%) cases. Surveillance without intervention occurred in 110 (62%) pts, and 34 (19%) pts underwent open and 35 (19%) endovascular repair. In all patients, preoperative imaging was performed, preferably by computed tomography angiography (CTA). RESULTS: A total of 69 patients underwent open or endovascular repair. 51 (74%) pts were treated electively, 18 (26%) pts presented urgently with acute bleeding. 16 emergency pts received endovascular treatment, and in 2 pts open surgery was performed. After emergency treatment, two pts exhibited segmental liver malperfusion without consequences. In one case, segmental bowel resection was necessary. 32/51 (63%) patients were treated electively by open surgery, 19/51 (37%) by endovascular procedures. There were no liver or bowel infarctions. Four splenectomies and one unilateral nephrectomy were necessary in patients with splenic or renal artery aneurysms. Moreover, three partial renal infarctions were noticed postoperatively (overall 8/21 [38%]). After endovascular repair of splenic or renal artery aneurysms, two cases of splenic and three cases of renal segmental infarction were observed. Splenectomy had to be performed twice (overall 7/14 [50%]). Organ perfusion was monitored by CTA, and preferentially by contrast enhanced ultrasound. CONCLUSION: The endovascular approach is the preferred option in an emergency to control bleeding in pseudoaneurysms. Patients for elective splenic or renal artery aneurysm repair have to be evaluated very carefully to achieve technical success with occlusion of the aneurysm and excellent organ perfusion. Imaging techniques such as ultrasound, especially CEUS, are strongly recommended in postoperative follow-up. Partial or complete splenic infarction leads to vaccination.

Standardized 2D ultrasound versus 3D/4D ultrasound and image fusion for measurement of aortic aneurysm diameter in follow-up after EVAR.

PURPOSE: To compare standardised 2D ultrasound (US) to the novel ultrasonographic imaging techniques 3D/4D US and image fusion (combined real-time display of B mode and CT scan) for routine measurement of aortic diameter in follow-up after endovascular aortic aneurysm repair (EVAR). METHOD AND MATERIALS: 300 measurements were performed on 20 patients after EVAR by one experienced sonographer (3rd degree of the German society of ultrasound (DEGUM)) with a high-end ultrasound machine and a convex probe (1-5 MHz). An internally standardized scanning protocol of the aortic aneurysm diameter in B mode used a so called leading-edge method. In summary, five different US methods (2D, 3D free-hand, magnetic field tracked 3D - Curefab™, 4D volume sweep, image fusion), each including contrast-enhanced ultrasound (CEUS), were used for measurement of the maximum aortic aneurysm diameter. Standardized 2D sonography was the defined reference standard for statistical analysis. CEUS was used for endoleak detection. RESULTS: Technical success was 100%. In augmented transverse imaging the mean aortic anteroposterior (AP) diameter was 4.0±1.3 cm for 2D US, 4.0±1.2 cm for 3D Curefab™, and 3.9±1.3 cm for 4D US and 4.0±1.2 for image fusion. The mean differences were below 1 mm (0.2-0.9 mm). Concerning estimation of aneurysm growth, agreement was found between 2D, 3D and 4D US in 19 of the 20 patients (95%). Definitive decision could always be made by image fusion. CEUS was combined with all methods and detected two out of the 20 patients (10%) with an endoleak type II. In one case, endoleak feeding arteries remained unclear with 2D CEUS but could be clearly localized by 3D CEUS and image fusion. CONCLUSION: Standardized 2D US allows adequate routine follow-up of maximum aortic aneurysm diameter after EVAR. Image Fusion enables a definitive statement about aneurysm growth without the need for new CT imaging by combining the postoperative CT scan with real-time B mode in a dual image display. 3D/4D CEUS and image fusion can improve endoleak characterization in selected cases but are not mandatory for routine practice.

Effects of endogenous nitric oxide and of DETA NONOate in arteriogenesis.

Previous studies showed that targeted endothelial nitric oxide synthase (eNOS) disruption in mice with femoral artery occlusion does not impede and transgenic eNOS overexpression does not stimulate collateral artery growth after femoral artery occlusion, suggesting that nitric oxide from eNOS does not play a role in arteriogenesis. However, pharmacologic nitric oxide synthase inhibition with L-NAME markedly blocks arteriogenesis, suggestive of an important role of nitric oxide. To solve the paradox, we studied targeted deletion of eNOS and of inducible nitric oxide synthase (iNOS) in mice and found that only iNOS knockout could partially inhibit arteriogenesis. However, the combination of eNOS knockout and treatment with the iNOS inhibitor L-NIL completely abolished arteriogenesis. mRNA transcription studies (reverse transcriptase-polymerase chain reaction) performed on collateral arteries of rats showed that eNOS and especially iNOS (but not neural nitric oxide synthase) become upregulated in shear stress-stimulated collateral vessels, which supports the hypothesis that nitric oxide is necessary for arteriogenesis but that iNOS plays an important part. This was strengthened by the observation that the nitric oxide donor DETA NONOate strongly stimulated collateral artery growth, activated perivascular monocytes, and increased proliferation markers. Shear stress-induced nitric oxide may activate the innate immune system and activate iNOS. In conclusion, arteriogenesis is completely dependent on the presence of nitric oxide, a large part of it coming from mononuclear cells.

Actin-binding rho activating protein (Abra) is essential for fluid shear stress-induced arteriogenesis.

OBJECTIVE: Arteriogenesis, the development of a collateral circulation, is important for tissue survival but remains functionally defective because of early normalization of fluid shear stress (FSS). Using a surgical model of chronically elevated FSS we showed that rabbits exhibited normal blood flow reserve after femoral artery ligature (FAL). Inhibition of the Rho pathway by Fasudil completely blocked the beneficial effect of FSS. In a genome-wide gene profiling we identified actin-binding Rho activating protein (Abra), which was highly upregulated in growing collaterals. METHODS AND RESULTS: qRT-PCR and Western blot confirmed highly increased FSS-dependent expression of Abra in growing collaterals. NO blockage by L-NAME abolished FSS-generated Abra expression as well as the whole arteriogenic process. Cell culture studies demonstrated an Abra-triggered proliferation of smooth muscle cells through a mechanism that requires Rho signaling. Local intracollateral adenoviral overexpression of Abra improved collateral conductance by 60% in rabbits compared to the natural response after FAL. In contrast, targeted deletion of Abra in CL57BL/6 mice led to impaired arteriogenesis. CONCLUSIONS: FSS-induced Abra expression during arteriogenesis is triggered by NO and leads to stimulation of collateral growth by smooth muscle cell proliferation.