CT virtual intravascular endoscopy of abdominal aortic aneurysms treated with suprarenal endovascular stent grafting

Background: We investigated the clinical applications of virtual intravascular endoscopy (VIE) in patients with abdominal aortic aneurysms (AAA) treated by endovascular stent grafting with a suprarenal component. Methods: Thirty-four patients with AAA undergoing endovascular stent grafting were included in the study (28 male, six female; mean age = 76 years). Helical computed tomography (CT) scanning was performed within 1 week after stent graft implantation. All patients received a Zenith/AAA endovascular graft with uncovered suprarenal struts 2.5 cm long placed around the level of the renal arteries. VIE images were created for each patient. The follow-up periods ranged from 3 to 18 months (mean = 8.3 ± 3.7 months). Results: Three of 34 celiac arteries, 22 of 34 superior mesenteric arteries, 32 of 34 right renal arteries, and 30 of 35 left renal arteries were affected by the suprarenal stent struts (wires) to different extents. VIE was able to demonstrate the struts, arterial ostia, and the strut/ostia configuration. Follow-up CT showed that all of these aortic branches were patent. Conclusion: Our preliminary experience has demonstrated that VIE is a novel imaging technique to visualize the three-dimensional intralumenal relationship of the aortic stent struts to the arterial ostia in patients with AAA after suprarenal stent graft placement.     

彩色多普勒超声在锁骨下动脉窃血综合征及内支架置放术中的应用

目的探讨彩色多普勒超声(CDU)在锁骨下动脉窃血综合征(SSS)及内支架置放术中应用价值。方法对31例SSS的超声表现及4例内支架置放术后的超声随访结果进行回顾性分析。结果31例患者中,28例为完全性SSS,3例部分性SSS。锁骨下动脉起始处闭塞18例,均为完全性SSS;狭窄13例,内径1~3.4mm,最大流速270~430cm/s。患侧上肢动脉血流频谱为单峰、低速、低阻波形。4例内支架置放术后,锁骨下动脉起始处内支架血流通畅;椎动脉和上肢动脉血流恢复正常。结论CDU是评价SSS及内支架置放术后随访的一种有价值方法。     

Resveratrol induces vasorelaxation of mesenteric and uterine arteries from female guinea-pigs

Naturally occurring hydroxystilbenes have been shown to induce vasorelaxation. Here, we studied the mechanism of resveratrol-induced vasorelaxation in different types of blood vessels, namely mesenteric (resistance) and main uterine (conductance) arteries, from female guinea-pigs on day 7 and day 15 of the oestrous cycle. Resveratrol (5-70 micromol/l) induced concentration-dependent relaxation of both mesenteric and uterine arteries preconstricted with either noradrenaline (NA; 10 micromol/l) or KCl (125 mmol/l). Resveratrol was 2-fold more potent in inducing relaxation of mesenteric arteries than of uterine arteries. Its effects on uterine arteries from both day-7 and day-15 guinea-pigs were similar, irrespective of the constrictor used, but it was significantly (P<0.01) more potent in inducing relaxation of mesenteric arteries contracted with NA compared with those constricted with KCl. In day-7 arteries precontracted with NA, N(G)-nitro-L-arginine methyl ester (L-NAME; 10 micromol/l) had no effects on the time course of resveratrol-induced vasorelaxation in either mesenteric or uterine arteries. However, indomethacin (50 micromol/l) significantly (P<0.05) potentiated resveratrol's effect on mesenteric, but not uterine, arteries. Indomethacin had no effect on resveratrol-induced vasorelaxation of arteries contracted with KCl, whereas L-NAME significantly (P<0.05) reduced the effects of resveratrol on uterine, but not on mesenteric, arteries. In day-15 arteries, L-NAME significantly (P<0.01) attenuated the effects of resveratrol on mesenteric arteries contracted with NA. Indomethacin had no effect on resveratrol activity. This study indicates that: (a) the effect of resveratrol on resistance arteries is greater than that on conductance arteries; (b) the effects of resveratrol are not mediated via prostanoids, but NO may play a role; and (c) the stage of the oestrous cycle has no influence on resveratrol-induced vasorelaxation.     

Postsynaptic alpha adrenoceptors in baboon cerebral and mesenteric arteries

Postsynaptic alpha adrenergic mechanisms were compared in cerebral and mesenteric arteries isolated from the baboon. The contractile response to norepinephrine (NE) of the cerebral artery was potent and similar to that of the mesenteric artery. The EC50 was 3.1 (2.0-5.0) X 10(-7) M for the cerebral artery and 2.6 (1.5-4.8) X 10(-7) M for the mesenteric artery. The maximum contraction expressed as a force developed/cross-sectional area did not differ between the two arteries, whereas that expressed as percentage of 30 mM KCl-induced contraction in the cerebral artery (118 +/- 9%) was less than in the mesenteric artery (145 +/- 6%). Phenylephrine produced a contraction in a manner similar to NE, although the EC50 values in both arteries were 2 to 3 times as large as those for NE. Clonidine produced a moderate contraction in the mesenteric artery (35 +/- 8% of the KCl-induced contraction) but no contraction in the cerebral artery. NE-induced contraction in the cerebral artery was inhibited more prominently by prazosin, a selective alpha-1 adrenoceptor antagonist, than that in the mesenteric artery; the pA2 value for prazosin in the cerebral artery was higher (9.70) than that in the mesenteric artery (8.95). In contrast, there was no difference in pA2 values for either phentolamine or yohimbine between the two arteries. Clonidine-induced contraction in the mesenteric artery was attenuated by prazosin rather than yohimbine at the same concentration used. Thus, it may be concluded that contractile processes related to postsynaptic alpha-1 adrenoceptor stimulation are predominantly operative in baboon cerebral and mesenteric arteries, the cerebral artery being more susceptible to the inhibitory effect of prazosin.     

Arachidonic acid-induced vasodilation of rat small mesenteric arteries is lipoxygenase-dependent

We examined the mechanism of arachidonic acid-induced vasodilation in rat small mesenteric arteries and determined the primary arachidonic acid metabolites produced by these arteries. Responses to arachidonic acid in small mesenteric arteries from Sprague-Dawley rats were investigated in vitro in the presence or absence of endothelium or after pretreatment with inhibitors of nitric oxide (NO), cyclooxygenase, cytochrome P450, lipoxygenase, or K+ channels. In addition, the metabolism of arachidonic acid was examined by incubating arteries with [3H]arachidonic acid in the presence and absence of cyclooxygenase, cytochrome P450, or lipoxygenase inhibitors. Finally, the vascular response to both 12(S)-hydroxyeicosatetraenoic acid (HETE) and 12(S)-hydroperoxyeicosatetraenoic acid (HPETE) was determined. Arachidonic acid induced an endothelium-dependent vasodilation that was abolished by lipoxygenase inhibitors [cin-namyl-3,4-dihydroxy-cyanocinnamate (CDC) or 5,8,11-eicosatriynoic acid (ETI)] and KCl, whereas it was partially inhibited by either tetraethylammonium or iberiotoxin. In contrast, neither NO nor cytochrome P450 enzyme inhibitors affected arachidonic acid-mediated dilation, whereas inhibition of cyclooxygenase enhanced dilation. Biochemical analysis revealed that small mesenteric arteries primarily produce 12-HETE, a lipoxygenase metabolite. Moreover, CDC and ETI inhibited the production of 12-HETE. Finally, both 12(S)-HETE and 12(S)-HPETE induced a concentration-dependent vasodilation in mesenteric arteries. These findings provide functional and biochemical evidence that the lipoxygenase pathway mediates arachidonic acid-induced vasodilation in rat small mesenteric arteries through a K+ channel-dependent mechanism.     

Effects of Bay k 8644 and nifedipine on isolated dog cerebral, coronary and mesenteric arteries

Vasoconstrictor effects of Bay k 8644, a dihydropyridine Ca++ agonist, and vasorelaxant effects of nifedipine were investigated in helical strips of dog cerebral (basilar, posterior cerebral and middle cerebral) and peripheral (coronary and mesenteric) arteries. The addition of Bay k 8644 produced a dose-dependent contraction in the absence of any contractile agent in the basilar artery with a pD2 value of 8.53. Similar sensitivity to Bay k 8644 was observed in the posterior cerebral, middle cerebral or coronary artery. Bay k 8644 was much less effective in producing a contraction in the mesenteric artery. An elevation of the concentration of extracellular K+ eliminated the difference between the responses to Bay k 8644 in the basilar and mesenteric artery. Contractile responses of the basilar artery to Bay k 8644 were antagonized competitively by nifedipine (pA2 = 8.17), but non-competitively by diltiazem. The pA2 values for nifedipine antagonism of Bay k 8644 responses with the elevated K+ were the same between the basilar and mesenteric arteries. Increased sensitivity to exogenously added K+ also was observed in cerebral and coronary arteries when compared with the mesenteric artery. The addition of nifedipine to an unstimulated strip produced a dose-dependent relaxation in cerebral and coronary arteries, but not in the mesenteric artery. When the cerebral and peripheral arteries were contracted with K+ to the same magnitude, nifedipine produced similar relaxations among these arteries. Nifedipine was less efficacious in antagonizing the contractile response to Bay k 8644 compared with the contractile response to K+ in cerebral arteries. These results suggest that 1) the voltage-dependent Ca++ channels in the cerebral and coronary arteries are in different states of activation from those in the mesenteric artery, 2) Bay k 8644 contracts the cerebral and coronary arteries by acting primarily on the same site, presumably dihydropyridine receptors of the voltage-dependent Ca++ channels at which nifedipine acts, 3) the dihydropyridine receptors were the same between the basilar and mesenteric arteries and 4) there may be a difference in the state of the Ca++ channel in the arteries between the stimulation with Bay k 8644 and K+-depolarization.     

彩色多普勒超声在锁骨下动脉狭窄介入治疗中的价值

目的 评价彩色多普勒超声在锁骨下动脉狭窄诊断及血管内支架植入术后随访中的价值.方法 对38例动脉粥样硬化性脑梗死或一过性脑缺血患者行数字减影血管造影（DSA）和彩色多普勒超声检查,检出锁骨下动脉近心段中至重度狭窄或闭塞44支（6例双侧）,40支行血管内成形和支架植入术,术后彩色多普勒超声对锁骨下动脉支架情况进行随访.结果 锁骨下动脉动脉粥样硬化性阻塞主要局限于近心段.彩色多普勒超声诊断锁骨下动脉近心段阻塞与DSA的符合率达90.9%（40/44）.35支锁骨下近心段阻塞合并盗血.手术成功率95%（38/40）.术后平均随访18个月（3～63个月）,发现8支支架植入术后再狭窄,分别为支架内内膜增生狭窄6支,支架弹性回缩及支架断裂塌陷狭窄各1支,血管植入支架后再狭窄率21.1%（8/38）.无严重并发症发生.结论 彩色多普勒超声诊断锁骨下动脉近心段狭窄准确可靠,可作为锁骨下动脉近心段阻塞性病变介入术前评价和术后随访中的首选手段.     

血管内支架治疗外周动脉狭窄或阻塞性疾病

目的 探讨血管内支架治疗外周动脉狭窄或阻塞性疾病的疗效和预后。方法 应用PTA加血管内支架技术,治疗13例外周动脉狭窄性疾病的患者。结果 13例动脉造影显示4例颈动脉、4例锁骨下动脉、4例肾动脉及1例腹主动脉有不同程度狭窄。12例应用导丝顺利完成PTA治疗后,置放自扩展式Wall stent、记忆合金式Symphony及Angiomed支架12支,患者治疗后临床症状消失或缓解。术后造影显示血管及支架通畅,近期效果满意。结论 应用PTA加血管内支架是治疗外周血管狭窄或闭塞性疾病的理想方法。     

Inferior mesenteric artery aneurysm combined with renal artery stenosis in a patient with neurofibromatosis

A case is reported of an inferior mesenteric artery aneurysm that starts approximately 1 cm from its origin and ends at the proximal portion of the bifurcation of the sigmoidal and left colic arteries accompanied with complete absence of the celiac axis and superior mesenteric arteries. Additionally, left renal artery stenosis existed. The diagnosis was made by digital subtraction arteriography and confirmed by magnetic resonance arteriogram. Disease involving the inferior mesenteric artery is extremely uncommon. This may be the first reported case of neurofibromatosis in combination with renal artery stenosis and inferior mesenteric artery aneurysm associated with celiac and superior mesenteric artery occlusion and treated surgically.     

Middle mesenteric artery visualized by computed tomographic angiography

The middle mesenteric artery, a third mesenteric artery arising from the aorta that principally feeds the transverse colon, is an extremely rare anomaly. We identified a middle mesenteric artery branching into the ileocolic artery and into the right, middle, and accessory middle colic arteries. It supplied the cecum and the entire ascending and transverse colon. This anomaly was detected with computed tomographic angiography.     

Nonadrenergic nature of prazosin-resistant, sympathetic contraction in the dog mesenteric artery

Electrical transmural stimulation of the isolated dog mesenteric artery produced a contractile response which was abolished by guanethidine and 6-hydroxydopamine but not by prazosin. Approximately 60% of the response seen with a frequency of 3 Hz remained after the treatment with prazosin. The prazosin-resistant contraction induced by electrical transmural stimulation was potentiated by other alpha adrenoceptor antagonists (phentolamine, phenoxybenzamine, tolazoline and DG-5128). Alpha-2 adrenoceptor agonists (including norepinephrine) attenuated the prazosin-resistant contraction and this attenuation was antagonized by the alpha antagonists mentioned above. Cocaine slightly inhibited the prazosin-resistant contraction, whereas this drug markedly augmented the contractile response to electrical stimulation before treatment with prazosin. In reserpine-treated mesenteric arteries also, electrical transmural stimulation produced a contraction and this was neither suppressed nor potentiated by prazosin and other alpha antagonists but was attenuated by alpha-2 agonists. Guanethidine and 6-hydroxydopamine abolished the prazosin-resistant contraction in reserpine-treated arteries. Nicotine, but not tyramine, also produced such prazosin-resistant contraction in reserpine-treated and untreated arteries. Exogenous norepinephrine produced a concentration-dependent contraction in reserpine-treated and untreated arteries and the responses were competitively antagonized by prazosin. These results indicate that the prazosin-resistant contractions of the dog mesenteric artery induced by electrical transmural stimulation and nicotine are sympathetic in origin but not adrenergic in nature. Such prazosin- resistant contraction was observed in the dog mesenteric vein but not in carotid and femoral arteries, thereby suggesting that the nonadrenergic component may play an important role in the regulation of visceral blood flow.     

Sonographic follow-up after visceral artery stenting.

OBJECTIVE: The aim of this study was to evaluate the sonographic features of stents and the flow parameters of the visceral arteries after stent implantation. METHODS: Since 1996, 34 stenoses of the visceral arteries (2 mesenteric, 4 celiac trunk, and 28 renal arteries) in 28 patients have been treated with metallic stent implantation in the Department of Radiology of Szeged Medical University. All these patients were regularly followed sonographically. For the diagnosis of restenosis, previously published criteria were used. RESULTS: All the mesenteric and celiac stents could be visualized, but none of the renal stents were clearly seen sonographically. The flow parameters could be established in all cases. Sonographic examination revealed 1 occlusion, 2 restenoses, and 1 stent displacement. All these abnormalities were confirmed by other imaging modalities. CONCLUSIONS: Sonography is a useful tool in the follow-up of patients after visceral artery stenting. Despite the fact that none of the renal artery stents were visualized directly, the flow parameters could be evaluated, and the pathologic changes were found.     

Superior mesenteric artery aneurysm stent graft

Visceral artery aneurysms represent 0.1% to 0.2% of all vascular aneurysms. They are mostly asymptomatic, but rupture is associated with a high mortality rate. We present a case of an asymptomatic aneurysm of the proximal superior mesenteric artery in a 64-year-old man that was successfully treated by implantation of a covered stent graft. The use of endovascular techniques to manage visceral artery aneurysms should be considered.     

Familial fibromuscular dysplasia of the mesenteric arteries

We have reported the case of a critically ill 17-year-old girl who had an evolving gastrointestinal infarction when she came to our institution 11 months before she died. After surgical revascularization, biopsy of the superior mesenteric artery showed FMD. We interviewed and examined all close consanguineous relatives and found abdominal bruits in the patient's younger sister and mother. Arteriograms showed total occlusion of the celiac and superior mesenteric arteries in the sister, and a subtotal celiac occlusion in the mother. Postprandial abdominal pain and constipation in the sister prompted elective mesenteric revascularization, and biopsy of the superior mesenteric artery confirmed FMD identical to that of her older sister. The mother, who is asymptomatic, has single vessel disease and has not required operative intervention. Our report strongly supports the hypothesis of a genetic basis for this arteriopathy.     

Acute mesenteric ischemia: endovascular therapy

Acute mesenteric ischemia (AMI) is an abdominal emergency with a high mortality. Prompt revascularization can prevent intestinal infarction and reduce mortality. We report three cases of acute occlusive mesenteric ischemia without signs of intestinal necrosis, which were successfully managed with endovascular interventions. Mechanical thrombus fragmentation was performed and underlying chronic stenoses were treated with stent implantation. All the patients had pain relief immediately after the procedure, and none of them required surgery for bowel resection. The patients remained symptom free during a follow-up of 12–16 months. We suggest that endovascular treatment is a feasible option in patients with AMI and can prevent intestinal infarction.     

Heterogeneity of endothelium-dependent vasodilation in pressurized cerebral and small mesenteric resistance arteries of the rat.

We compared endothelial responses to calcium-mobilizing agents in mesenteric and cerebral resistance arteries of the rat. Middle cerebral and small mesenteric arteries were mounted in a pressure myograph, and myogenic responses were recorded. The effects of acetylcholine (ACh), bradykinin, substance P, histamine, A23187, cyclopiazonic acid (CPA), and sodium nitroprusside were investigated in both arteries with myogenic tone in the absence and presence of nitric oxide synthase and cyclooxygenase inhibitors. The effects of raised potassium, K(+) channel blockers, and arachidonic metabolism inhibition were examined on the nitric oxide (NO) synthase/cyclooxygenase inhibitor-resistant dilation induced by ACh and CPA. Cerebral arteries display a high level of myogenic reactivity compared with mesenteric arteries. In cerebral arteries, only bradykinin and substance P induced endothelium-dependent dilation. The observed dilation was solely related to the activation of the NO pathway. However, in mesenteric arteries, all of the vasoactive agents induced endothelium-dependent dilation. A combination of NO, cyclooxygenase-derived prostanoids, and a factor with endothelium-derived hyperpolarizing factor-like properties was responsible for the observed vasodilation. NO and cyclooxygenase derivatives were able to compensate for each other in the CPA-induced endothelium-dependent vasodilation when one of the two pathways was blocked. Moreover, small Ca(2+)-activated K(+) channels and a combination of both large and small Ca(2+)-activated K(+) channels were implicated in the endothelium-derived hyperpolarizing factor-like component of dilation to ACh and CPA, respectively. Finally, the results suggest that the pathway by which agonists raise intracellular calcium concentration may determine the nature of the endothelial secretory product.     

Actions of cyclosporin A preparation and Cremophor-EL in rabbit mesenteric artery and thoracic aorta in vitro.

1. We studied the in vitro and direct effects of intravenous cyclosporin A preparation (Sandimmun) and its solvent (Cremophor-EL) on acetylcholine-induced endothelium-dependent relaxation, phenylephrine-induced contraction and drug-induced contraction of rabbit thoracic aorta and superior mesenteric artery segments. 2. At the lower concentration (5 micrograms/ml), cyclosporin A preparation inhibited endothelium-dependent relaxation of the superior mesenteric artery but not of the thoracic aorta. At this concentration cyclosporin A preparation augmented phenylephrine-induced contraction in both segments but by more in the superior mesenteric artery, and induced a slow increase in the tone of isolated superior mesenteric artery and thoracic aortic rings, which was greater in magnitude in the superior mesenteric artery than in the thoracic aorta. 3. Acetylcholine-induced endothelium-dependent relaxation was inhibited by cyclosporin A preparation (50 micrograms/ml) in both arteries but to a greater extent in the superior mesenteric artery. 4. The solvent of the intravenous cyclosporin A preparation (Cremophor-EL) in concentrations corresponding to those of the drug caused less inhibitory effects than cyclosporin A preparation on acetylcholine-induced endothelium-dependent relaxation, had comparable effects on phenylephrine-induced contraction, and produced similar contractions of both arteries. 5. The results indicate that Cremophor-EL may contribute to the inhibitory action of cyclosporin A preparation on acetylcholine-induced endothelium-dependent relaxation in the superior mesenteric artery, but is fully responsible for the smooth-muscle-contracting effect and the potentiation of phenylephrine-induced contraction in both arteries.     

消化间期意识清醒狗胃左动脉及肠系膜上动脉血流变化的对比研究

目的消化间期意识清醒狗发生周期性胃肠道移行性复合肌电运动（MMC）。本研究选择支配胃肠的主要动脉-胃左动脉（LGA）和肠系膜上动脉（SMA）,探讨MMC时LGA和SMA的血流动力学的变化。方法选择5条意识清醒的狗,用超声波传输时间血流仪（ultrasound transit-time blood flow meters）持续测定LGA和SMA的血流。十二指肠的收缩期（phaseⅢ期）结束后30分钟,静脉内持续性滴注胃动素（12.5,25,50和100 pmol/kg/h）达30分钟。在另一个研究系列里,在有或无atropine（50μg/kg followed by 25μg/kg/h）的情况下,把溶解在1 ml生理盐水里的胃动素或VIP（5,10,20,40和80 pmol/kg）1分钟内静脉推注。结果胃动素（12.5,25,50和100 pmol/kg/h）均诱导了LGA血流的增加,但对SMA、血压和心率没有影响。胃动素诱导的胃血管舒张作用有意义的大于VIP（Vasoactive intestinal polypeptide,血管活性肠肽）的同等剂量。结论消化间期LGA血流与MMC同步发生周期性的变化,而SMA则持续平稳的维持在基础血流水平;胃动素是一个有效的而且是高度选择性的胃血管舒张剂,其在消化间期胃血流的调节中起着非常重要的作用。     

Enhancement of vasoconstrictor responses to 5-HT but no to methoxamine by cooling in isolated dog lingual and mesenteric arteries

The effect of temperature on submaximal vasoconstrictions to an intraluminal injection of serotonin (5-HT) and methoxamine was investigated in isolated and perfused canine lingual and mesenteric arteries, using the cannula insertion method. In both arteries cooling (from 37 degrees C to 27 degrees C) caused a remarkable enhancement of vasoconstriction to 5-HT, but did not to methoxamine. In lingual arteries, methoxamine-induced constrictions were strongly depressed, although those were slightly depressed in mesenteric arteries. It is assumed that 5-HT produces an important role to modulate vascular tonicity in low temperature conditions.