Ruptured aneurysm in collateral arteries with blood-flow impairment of posterior inferior cerebellar artery: a report of three cases

Herein, we report three cases of cerebellar hemorrhage due to a ruptured small aneurysm located on a collateral artery compensating for one or more stenotic or occluded major cerebellar arteries. In each case, endovascular distant parent artery occlusion of both the collateral artery and aneurysm was performed to prevent rebleeding. A ruptured small aneurysm in a collateral artery may be observed in patients with hemorrhage in an atypical cerebellar region, especially in cases of stenosis or occlusion of the vertebral artery or posterior inferior cerebellar artery. Thus, cerebral angiography is recommended to rule out collateral artery aneurysm.

A rare case of sigmoid colon cancer in which the lower limbs received collateral blood flow from the inferior mesenteric artery owing to peripheral artery disease

Background

Colorectal cancer and peripheral artery disease are common conditions in older adults and may coexist in this population. Lymph node dissection along the inferior mesenteric artery is a vital procedure in cases of left-sided colorectal cancer. However, the inferior mesenteric artery may show a collateral blood pathway in rare cases of peripheral artery disease. We report a case of advanced sigmoid colon cancer in which the lower limbs received inferior mesenteric artery flow owing to asymptomatic peripheral artery disease. The possibility of catastrophic lower-limb ischemia because of complete mesenteric excision with ligation of the inferior mesenteric artery was a matter of concern in this case.

Case presentation

A 73-year-old man with asymptomatic peripheral artery disease was diagnosed with stage IIIB advanced sigmoid colon cancer. Angiography using a balloon-occlusion catheter revealed that his lower limbs received prominent inferior mesenteric artery blood flow through a collateral pathway. Therefore, interventional radiologists and cardiovascular surgeons evaluated the indications for endovascular stents or bypass grafts. The patient also had dilated cardiomyopathy, so the cardiovascular physicians evaluated his tolerance in the worst-case scenario of a colorectal anastomotic leak. The patient underwent axillofemoral artery bypass and two-stage laparoscopic sigmoid colectomy without anastomosis. The postoperative course was uneventful, and he resumed his job within a month after the resection.

Conclusions

Although collateral flow from the inferior mesenteric artery is rare in patients with peripheral artery disease, a few case reports have described fatal lower-limb ischemia following anterior resection. The perioperative multidisciplinary evaluation enabled us to understand the patient’s condition and risks, and allowed successful cancer treatment without ischemia of the lower limbs.

Sumo-Associated Traumatic Vertebral Artery Dissection Precipitating Subarachnoid Hemorrhage in Association with Bifid Origins of the Posterior Inferior Cerebellar Artery

BACKGROUND

Traumatic vertebral artery dissection (tVAD) is frequently accompanied by cerebellar infarction, but subarachnoid hemorrhage (SAH) is rare.

CASE DESCRIPTION

We report a unique case of tVAD precipitating SAH, from which the patient fully recovered, most likely because of the protective effects of an anomalously duplicated posterior inferior cerebellar artery (PICA) origin. A 17-year-old Sumo wrestler experienced a brief loss of consciousness after an attack by an opponent to his neck. Head computed tomography imaging demonstrated diffuse posterior fossa SAH; cerebral angiography demonstrated left vertebral artery (VA) occlusion, which was thought to be most likely attributable to tVAD. Angiography revealed distal PICA reconstitution, supplied by collateral arterial flow from the meningeal branch of the proximal ipsilateral VA. An external ventricular drain was placed acutely for treatment of SAH-induced hydrocephalus; however, the patient had an otherwise uneventful course, and remained without clinical evidence of ischemic infarct. A repeat imaging confirming a probable duplicated PICA origin from the VA, distal to the tVAD-associated thrombosis.

CONCLUSIONS

Of particular interest, the patient's abnormal anatomy may have been a mixed blessing, with a more fragile bifid PICA potentially underlying the unexpected development of SAH, whereas the sister branch simultaneously spared him a potentially catastrophic infarction via arterial collateralization.

Scimitar sign in the absence of anomalous pulmonary venous drainage: a case report

Background

Scimitar syndrome consists of anomalous pulmonary vein drainage to the inferior vena cava. Its name derives from the image this anomalous pulmonary vein creates on a chest radiograph. We describe a case of normal venous pulmonary vein drainage that also presented the scimitar sign due to an aorto-collateral vessel.

Case summary

A 15-month-old girl presented with mild dyspnoea and fever. Control chest X-ray showed an image of cardiac dextroposition, hypoplastic right lung, and the ‘scimitar sign’. Although the transthoracic echocardiogram confirmed the initial suspicion of anomalous pulmonary venous drainage, the computed tomography (CT) scan showed normal right pulmonary veins connected to the left atrium and revealed that an aorto-collateral vessel caused the scimitar sign.

Discussion

Although the patient had several typical alterations of the scimitar syndrome, the pulmonary venous connection was normal, and the scimitar sign was due to an aorto-collateral vessel. It might be difficult to describe venous pulmonary connections on the basis of echocardiography, so an angio CT scan proved to be a valuable tool in this scenario.

Collateral artery pathways of the femoral and popliteal artery

BACKGROUND

The role of collateral artery circulation in the lower limb is under debate but clinically relevant, particularly when using covered stents for occlusive disease. Covered stents seem to outperform nitinol stents in extensive disease, but collaterals could be essential in case of acute thrombosis. In the present study, we describe the collateral pathways of the deep and superficial femoral artery (DFA, SFA) and the popliteal artery (PA), observed in human cadavers.

METHODS

Ten fresh frozen cadaver legs were selected. The SFA and DFA were separately cannulated and injected with a different colored latex mixture simultaneously. After curing of the latex, the circulation was dissected thus visualizing the main arteries and their collateral vessels. The process was photographed and recorded, and collateral pathways were analyzed using a standardized vessel segmentation. The upper leg was divided in three regions, that is, the femoral triangle (F), the adductor canal (H), and the popliteal fossa (P) that, in turn, were split in three segments (1, 2, and 3, from proximal to distal).

RESULTS

Overall, 113 collateral vessels were found; 69 originated from the DFA, 34 from the SFA, and 10 from the PA. The majority of collaterals originating from the DFA terminated in the SFA (57%). Fifty-six of 113 collaterals (50%) ended in either the distal adductor channel (H3) or the proximal PA (P1). Another 28 collateral arteries (25%) had their origin in this segment (H3, P1) and mostly connected to the P2 and P3 segments. Forty-three collaterals of the DFA and H3 segment had a direct or indirect connection to below the knee muscles.

CONCLUSIONS

The majority of collaterals originate from the DFA, and the greater part of all collaterals has a connection with the H3-P1 segment. This observation may have clinical implications in the planning of endovascular procedures.

Genetic lineage tracing discloses arteriogenesis as the main mechanism for collateral growth in the mouse heart

Aims

Capillary and arterial endothelial cells share many common molecular markers in both the neonatal and adult hearts. Herein, we aim to establish a genetic tool that distinguishes these two types of vessels in order to determine the cellular mechanism underlying collateral artery formation.

Methods and results

Using Apln-GFP and Apln-LacZ reporter mice, we demonstrate that APLN expression is enriched in coronary vascular endothelial cells. However, APLN expression is reduced in coronary arterial endothelial cells. Genetic lineage tracing, using an Apln-CreER mouse line, robustly labelled capillary endothelial cells, but not arterial endothelial cells. We leveraged this differential activity of Apln-CreER to study collateral artery formation following myocardial infarction (MI). In a neonatal heart MI model, we found that Apln-CreER-labelled capillary endothelial cells do not contribute to the large collateral arteries. Instead, these large collateral arteries mainly arise from pre-existing, infrequently labelled coronary arteries, indicative of arteriogenesis. Furthermore, in an adult heart MI model, Apln-CreER activity also distinguishes large and small diameter arteries from capillaries. Lineage tracing in this setting demonstrated that most large and small coronary arteries in the infarcted myocardium and border region are derived not from capillaries, but from pre-existing arteries.

Conclusion

Apln-CreER-mediated lineage tracing distinguishes capillaries from large arteries, in both the neonatal and adult hearts. Through genetic fate mapping, we demonstrate that pre-existing arteries, but not capillaries, extensively contribute to collateral artery formation following myocardial injury. These results suggest that arteriogenesis is the major mechanism underlying collateral vessel formation.

Resection of a locally advanced hilar tumor and the hepatic artery after stepwise hepatic arterial embolization: A case report

We herein report a case of a hilar tumor with extensive invasion to the proper hepatic artery, which was successfully treated with a radical resection in a 57-year-old female patient after a stepwise hepatic arterial embolization. She underwent right colectomy and partial hepatectomy for advanced colon cancer two years ago and radiofrequency ablation therapy for a liver metastasis one year ago, respectively. A recurrent tumor was noted around the proper hepatic artery with invasion to the left hepatic duct and right hepatic artery 7 mo previously. We planned a radical resection for the patient 5 mo after the absence of tumor progression was confirmed while he was undergoing chemotherapy. To avoid surgery-related liver failure, we tried to promote the formation of collateral hepatic arteries after stepwise arterial embolization of the posterior and anterior hepatic arteries two weeks apart. Finally, the proper hepatic artery was occluded after formation of collateral flow from the inferior phrenic and superior mesenteric arteries was confirmed. One month later, a left hepatectomy with hepatic arterial resection was successfully performed without any major complications.