Inferior Mesenteric Artery Side Branch for Selected Patients with Endovascular Aortic Aneurysm Repair.

OBJECTIVE/BACKGROUND: To report on our experience of the treatment of aortic aneurysms by custom-made, branched stent-grafts with an additional inferior mesenteric artery (IMA) side branch to preserve IMA perfusion in patients at risk for colon ischemia. METHODS: Three male patients (mean age 60 years) with a thoracoabdominal, pararenal, and infrarenal aortic aneurysm (AA), respectively, were treated by endovascular aneurysm exclusion using custom-made, branched stent-grafts with a side branch to the IMA for prevention of colon ischemia. Indications for selective IMA side branch perfusion were occlusions or high-grade stenosis of the visceral or hypogastric arteries. RESULTS: No colon ischemia and no neurological deficit were observed. All three IMA side branches were perfused and patent, as documented by computed tomography scan and duplex ultrasound postoperatively and after 12 months. Patency after 24 months was documented as 2/3. CONCLUSION: Custom-made, branched stent-grafts are an endovascular option to preserve the IMA perfusion in selected, electively treated patients with an increased risk for insufficient colon perfusion due to stenosis or occlusions of visceral or hypogastric arteries.

[The significance of contrast-enhanced ultrasound in vascular surgery]. / Stellenwert der Kontrastmittelsonografie in der Gefäßchirurgie.

BACKGROUND: Vascular contrast-enhanced ultrasound (CEUS) is a special ultrasound application without the harmful side effects of nephrotoxicity and radiation exposure. CEUS can be used for advanced diagnosis of carotid stenosis and follow-up checks of endovascular repair of abdominal aortic aneurysms (EVAR). Low-flow phenomenon in peripheral vascular disease can easily be detected by enhanced colour-coded duplex sonography (CCDS). METHODS: The technical requirements of CEUS are explained here for the aorta, carotid, and peripheral arteries. The benefits and risks compared to computed tomography (CT), magnetic resonance (MR) and angiography are evaluated. Based on a selective review of the literature and the authors' personal experiences, CEUS is recommended for routine surveillance after EVAR. RESULTS: CEUS is a safe method using SonoVue® (Bracco) as the only approved agent for vascular examination. Special equipment and training is necessary. In prospective studies and meta-analyses the detection and characterisation of endoleaks is comparable to that of CT imaging. Neovascularisation as a sign of carotid plaques at risk can be seen without the need for invasive treatment. Imaging of crural vessels with enhanced CCDS is a promising but rarely needed option in diabetic and renally insufficient patients. CONCLUSION: CEUS in vascular medicine should be performed prior to other methods to avoid nephrotoxic contrast agents for the patients, especially in follow-up checks after EVAR. The time and effort required are still limiting its practical breakthrough.

Cerebral arteriogenesis is enhanced by pharmacological as well as fluid-shear-stress activation of the Trpv4 calcium channel.

OBJECTIVES: This study aimed to determine the importance of the shear-stress-sensitive calcium channels Trpc1, Trpm7, Trpp2, Trpv2 (transient receptor potential cation channel, subfamily V, member 2) and Trpv4 for cerebral arteriogenesis. The expression profiles were analysed, comparing the stimulation of collateral growth by target-specific drugs to that achieved by maximum increased fluid shear stress (FSS). DESIGN: A prospective, controlled study wherein rats were subjected to bilateral carotid artery ligature (BCL), or BCL + arteriovenous fistula, or BCL + drug application. METHODS: Messenger RNA (mRNA) abundance and protein expression were determined in FSS-stimulated cerebral collaterals by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry. Drugs were applied via osmotic mini pumps and arteriogenesis was evaluated by post-mortem angiograms and Ki67 immunostaining. RESULTS: Trpv4 was the only mechanosensitive Trp channel showing significantly increased mRNA abundance and protein expression after FSS stimulation. Activation of Trpv4 by 4α-phorbol-12,13-didecanoate caused significantly enhanced collateral growth (length: 4.43 ± 0.20 mm and diameter: 282.6 ± 8.1 µm) compared with control (length: 3.80 ± 0.06 mm and diameter: 237.3 ± 5.3 µm). Drug application stimulated arteriogenesis to almost the same extent as did maximum FSS stimulation (length: 4.61 ± 0.07 mm and diameter: 327.4 ± 12.6 µm). CONCLUSIONS: Trpv4 showed significantly increased expression in FSS-stimulated cerebral collaterals. Pharmacological Trpv4 activation enhanced cerebral arteriogenesis, pinpointing Trpv4 as a possible candidate for the development of new therapeutic concepts.

Exercise linked to transient increase in expression and activity of cation channels in newly formed hind-limb collaterals.

OBJECTIVE: This study aimed to compare arteriogenesis after femoral artery occlusion as influenced by exercise or arteriovenous shunt and follow changes in collateral transient receptor potential cation channel, subfamily V, member 4 (Trpv4). DESIGN: A prospective, controlled study wherein rats were subjected to femoral artery ligation (FAL), or FAL+arteriovenous shunt. Collateral Trpv4 was determined 0.5 and 6h post exercise. METHODS: Rats were subjected to exercise for 15 min, twice daily. The number and diameter of collaterals were assessed after 7 days. Collateral Trpv4 expression was quantified by reverse transcription-polymerase chain reaction. RESULTS: Collateral number and diameter per limb were significantly higher in the shunt group (number: 16.0+/-2.4 and diameter: 216.0+/-34 microm) compared to the ligature (number: 9.4+/-2 and diameter: 144+/-21 microm) and exercise groups (number: 9.9+/-2.5 and diameter: 151+/-15 microm). Trpv4 expression in collaterals harvested 0.5h post exercise was not significantly different from expression in shunted rats. It was significantly lower in collaterals harvested 6h post exercise (comparable to that in ligated rats). CONCLUSION: Collateral formation was greater in the shunt group than in the exercise group. Exercise-induced Trpv4 up-regulation, not significantly different from that achieved with shunt, returned to control values when evaluated 6h post exercise. More frequent exercise to chronically increase fluid shear stress, as with a shunt model, may be required for sufficient arteriogenesis to compensate for peripheral occlusion.