Preoperative Vascular Imaging Research Articles

Article Commentary: “Vertebral Artery Injury during Routine Posterior Cervical Exposure: Case Reports and Review of Literature”

Article Commentary: “Vertebral Artery Injury during Routine Posterior Cervical Exposure: Case Reports and Review of Literature”

Preoperative vascular imaging for predicting intraoperative modification of peripheral arterial cannulation during minimally invasive mitral valve surgery.

Minimally invasive mitral valve surgery using peripheral cannulation for cardiopulmonary bypass (CBP) is increasingly prevalent. Although conceptually straightforward, peripheral CBP involves challenges and risks specific to this method of perfusion. The utility of preoperative vascular imaging in predicting these technical challenges and preventing vascular complications was studied. We performed a retrospective analysis of 73 consecutive patients undergoing minimally invasive mitral valve surgery using femorofemoral CBP with intraluminal aortic occlusion balloon catheter. All patients underwent preoperative computed tomography angiogram or magnetic resonance angiography to study the iliofemoral axes. None of the patients operated with this technique was found to have arterial stenoses. Patients with a femoral artery diameter of less than 7.3 mm needed bilateral or side-graft arterial cannulation significantly more frequently than patients with larger femoral arteries (46.2% vs 9.1%, P = 0.001). There was a trend toward more frequent modification of arterial cannulation strategy in patients with body surface area less than 1.7 m compared with larger patients (body surface area, 1.7-2.0) (26.3% vs 8.3%, P = 0.07). Patients needing high CBP flow rate (>5 L/min) were no more likely to need dual arterial cannulation (18.2% vs 19.1%, P = 0.68). No patient experienced a vascular complication. This preliminary study suggests that preoperative vascular imaging and patient evaluation may predict difficulties with femoral cannulation and perfusion, which can lead to better preoperative planning and potentially prevent vascular complications. Further data will be accumulated and analyzed to confirm these findings.

Preoperative Vascular Imaging for Predicting Intraoperative Modification of Peripheral Arterial Cannulation during Minimally Invasive Mitral Valve Surgery

Preoperative Vascular Imaging for Predicting Intraoperative Modification of Peripheral Arterial Cannulation during Minimally Invasive Mitral Valve Surgery

Neuronavigation using susceptibility-weighted venography: application to deep brain stimulation and comparison with gadolinium contrast.

Careful trajectory planning on preoperative vascular imaging is an essential step in deep brain stimulation (DBS) to minimize risks of hemorrhagic complications and postoperative neurological deficits. This paper compares 2 MRI methods for visualizing cerebral vasculature and planning DBS probe trajectories: a single data set T1-weighted scan with double-dose gadolinium contrast (T1w-Gd) and a multi-data set protocol consisting of a T1-weighted structural, susceptibility-weighted venography, and time-of-flight angiography (T1w-SWI-TOF). Two neurosurgeons who specialize in neuromodulation surgery planned bilateral STN DBS in 18 patients with Parkinson's disease (36 hemispheres) using each protocol separately. Planned trajectories were then evaluated across all vascular data sets (T1w-Gd, SWI, and TOF) to detect possible intersection with blood vessels along the entire path via an objective vesselness measure. The authors' results show that trajectories planned on T1w-SWI-TOF successfully avoided the cerebral vasculature imaged by conventional T1w-Gd and did not suffer from missing vascular information or imprecise data set registration. Furthermore, with appropriate planning and visualization software, trajectory corridors planned on T1w-SWI-TOF intersected significantly less fine vasculature that was not detected on the T1w-Gd (p < 0.01 within 2 mm and p < 0.001 within 4 mm of the track centerline). The proposed T1w-SWI-TOF protocol comes with minimal effects on the imaging and surgical workflow, improves vessel avoidance, and provides a safe cost-effective alternative to injection of gadolinium contrast.

Indocyanine Green Angiography in the Surgical Management of Cerebral Arteriovenous Malformations

Indocyanine green (ICG) angiography is commonly used to map the vascular configuration of cerebral arteriovenous malformations (AVMs) during resection. To determine whether ICG improves rates of resection and clinical outcomes. A retrospective chart review was done for all patients undergoing resection of an AVM by the senior author (R.F.S.) between 2007 and 2011. Operative reports, hospital records, and radiographic imaging were used to determine the use of ICG, the incidence of residual disease, and clinical outcomes. A total of 130 cases (56 ICG, 74 non-ICG) were identified. Average AVM grade (2.2 vs 2.4) and size (2.7 vs 2.7 cm) were similar between the ICG and non-ICG groups, respectively. ICG was more often used when the AVM nidus was close to the cortical surface (71.4% vs 17.6%; P = .001) or lobar (82.1% vs 54.1%; P = .008). Eighteen patients (13.8%) were noted to have residual disease. Reoperation rates and change in modified Rankin Scale score were not different between the 2 groups (12.5% vs 14.9%, P = .8; 0.6 vs 0.4, P = .17). There were no ICG-attributable complications. ICG videoangiography is a quick and safe method of intraoperatively mapping the angioarchitecture of superficial AVMs, but it is less helpful for deep-seated lesions. This modality alone does not improve the identification of residual disease or clinical outcomes. Surgeon experience with extensive study of preoperative vascular imaging is paramount to achieving acceptable clinical outcomes. Formal angiography remains the gold standard for the evaluation of AVM obliteration.

Factors influencing the necessity for preoperative vascular imaging before harvesting a vascularized fibular flap

This study was carried out to identify groups of patients who would benefit from this angiography. The angiographic images of a random group of patients were studied; the correlations between the vascular state of the lower extremities and vessel pathology were investigated; and the possible links of these findings with certain medical conditions were explored. Three experienced observers independently evaluated the angiograms of 185 patients. The status of all 3 vessels of the lower extremities (anterior tibial artery, posterior tibial artery, and peroneal artery) was evaluated. The patients' gender, age, drinking and smoking habits, and medical conditions were documented. We found a significant correlation between pathology of the arteries of the lower extremity and blood cholesterol level, blood pressure, coronary heart disease, diabetes mellitus, and age. We suggest that preoperative vascular imaging be carried out in patients with comorbidities to reduce the potential for flap failure and to minimize donor site complications.

Internal Carotid Artery Variations in Velocardiofacial Syndrome Patients and Its Implications for Surgery

Medially displaced internal carotid arteries in velocardiofacial syndrome carry a risk during pharyngeal flap surgery. This study was designed to evaluate the frequency of medially deviated internal carotid arteries in both velocardiofacial syndrome patients and the general pediatric population and to assess the minimum distance to the pharyngeal walls to define the potential risk of internal carotid artery injury during pharyngeal surgery. Twenty-three consecutive patients with velocardiofacial syndrome who underwent posterior pharyngeal flap surgery and 21 control subjects who did not have velocardiofacial syndrome but who underwent oropharynx magnetic resonance imaging were reviewed. Medial deviation of at least one internal carotid artery was documented in 10 velocardiofacial syndrome patients (43.5 percent), compared with three patients (14.3 percent) in the control group (p=0.034). The mean±SD minimum distance to the posterior pharyngeal wall was 3.78±1.86 mm in velocardiofacial syndrome patients and 9.17±2.94 mm in the control group (p=0.014). Only one patient had significant medial dislocation of the internal carotid artery, and the closest distance from the pharyngeal wall was 0.86 mm. In velocardiofacial syndrome patients, medial dislocation of the internal carotid artery was common, and the minimum distance to the pharyngeal wall was short compared with the control group. However, in most of the authors' patients, the course of the cervical portion of the internal carotid artery is irrelevant to pharyngeal flap surgery. The authors conclude that preoperative vascular imaging study is not cost-effective in velocardiofacial syndrome patients but that intraoperative use of ultrasound imaging is still valuable for the purpose of planning pharyngeal flap surgery. Risk, II.

Computed tomography-based preoperative vascular imaging in autologous breast reconstruction: A Canadian perspective

There appears to be increased use of computed tomography angiography (CTA) in the preoperative planning of autologous perforator flap breast reconstruction. Despite the advantages of providing superior anatomical detail, concerns regarding cost and radiation exposure of this technique remain. In the current study, a paper-based survey was distributed to 44 plastic surgeons with a special interest in breast reconstruction at 19 different centres across Canada to collect their perspectives and practice characteristics with respect to the use of CTA as a preoperative imaging modality in breast reconstruction. The response rate of the survey was 75%. The majority of respondents commonly use perforator flap breast reconstruction and CTA in their breast reconstruction practice. Surgeons identified particular benefits of CTA in patients who had previously undergone abdominal surgery. However, more than one-half of the overall cohort was concerned about radiation exposure associated with CTA. A review of the literature suggests that it may be worthwhile to reduce the unnecessary risks of additional radiation exposure to the breast cancer population. A prospective study may help to better define the group of patients in whom CTA will provide optimal benefits in terms of reducing perioperative microvascular morbidity.

Computed tomography-based preoperative vascular imaging in autologous breast reconstruction: A Canadian perspective

Computed tomography-based preoperative vascular imaging in autologous breast reconstruction: A Canadian perspective

Caught between a disc and a tumour: lumbar radiculopathy secondary to disc herniation and filum paraganglioma

Dear Editor, Nerve root compression secondary to a combination of lumbosacral disc herniation and intrathecal space-occupying lesion is a rare co-incidence, particularly when histology reveals a paraganglioma. Cauda equina paraganglioma is a rare tumour that can be hypervascular and is associated with neuroendocrine disturbance during intraoperative tumour manipulation. Dual extraand intra-thecal pathology is unusual in the spine but can be addressed by a single operation to good effect. A 33-year-old gentleman was referred with a 12month history of persistent left leg sciatica associated with troublesome paraesthesiae in the left S1 dermatome. Neurological examination revealed 4+/5 left plantar flexion, an absent left ankle reflex and reduced pinprick sensation in the S1 dermatome. MR imaging of the lumbar spine revealed an avidly enhancing, intrathecal space-occupying lesion at the L5/S1 level (1.5×2 cm) as well as a large posterolateral L5/S1 disc protusion, resulting in S1 nerve root compression (Fig. 1). The patient underwent L5 and S1 laminectomies followed by intrathecal resection of a dark red, encapsulated lesion. Bipolar coagulation of the attached filum terminale arrested the tumour blood supply prior to manipulation. After dural closure, the left S1 root was retracted and a microdiscectomy was performed (Fig. 2). The patient was pain-free postoperatively with resolution of his antalgic gait, regaining the ability to walk on tiptoes. Histology revealed paraganglioma (WHO I) (Fig. 3). Followup imaging at 12 months did not reveal any evidence of recurrence, and the patient remained asymptomatic. Cauda equina paraganglioma (CEP) accounts for 3–4 % of all tumours in the region of the cauda equina [6]. There are no particular radiological features that reliably distinguish this entity from other more commonly encountered tumours at this site, such as ependymoma or nerve sheath tumour. The literature classifies CEP as a distinct sub-category of paraganglioma since its first description in 1970 by Miller and Torack [4]. CEP is thought to derive from primitive neural crest cells; however, whether the pathogenesis is due to aberrant migration of paraganglioma cells or the non-regression of paraganglioma cell nests is unclear [3]. The most common presenting symptoms of CEP are low back pain (51 %) and sciatica (19 %) [2]. CEP is found as commonly attached to the filum terminale as it is to nerve roots. Spinal paraganglioma has a characteristic vascular and endocrine phenotype. Typically, histopathology reveals small, rounded, polyhedral cells arranged in nests or ‘Zellballen’. Immunohistochemistry is positive for a variety of markers for both chief and sustenacular cells, including synaptophysin, chromogranins A and B, and S-100 protein [3]. CEP can demonstrate hormonal activity; however, in the largest review in the literature to date, this was found in only 3/174 cases (approximately 2 %) [2]. Intraoperative release of catecholaminergic hormones during tumour manipulation can result in haemodynamic instability, and we advise early vascular detachment. CEP can be highly vascular, and some authors advocate preoperative vascular imaging [1]. Gross R. Bhatia (*) : L. Zrinzo Victor Horsley Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK e-mail: robbhatia@yahoo.com

Peripheral arterial disease in diabetic patients with renal insufficiency: a review

Peripheral arterial disease is common among diabetic patients with renal insufficiency, and most of the diabetic patients with end-stage renal disease (ESRD) have peripheral arterial disease. Ischaemia is probably overrepresented as an etiological factor for a diabetic foot ulcer in this group of patients compared with other diabetic patients. ESRD is a strong risk factor for both ulceration and amputation in diabetic patients. It increases the risk of nonhealing of ulcers and major amputation with an OR of 2.5-3. Renal disease is a more important predictor of poor outcome after revascularizations than commonly expected. Preoperative vascular imaging is also affected by a number of limitations, mostly related to side effects of contrast agents poorly eliminated because of kidney dysfunction. Patients with renal failure have high perioperative morbidity and mortality. Persistent ischaemia, extensive infection, forefoot and heel gangrene, poor run-off, poor cardiac function, and the length of dialysis-dependent renal failure all affect the outcome adversely. Despite dismal overall outcome, recent data indicate that by proper selection, favourable results can be obtained even in ESRD patients, with the majority of studies reporting 1-year limb salvage rates of 65-75% after revascularization among survivors. High 1-year mortality of 38% reported in a recent review has to be taken into consideration, though. The preferential use of endovascular-first approach is attractive in this vulnerable multimorbid group of patients, but the evidence for endovascular treatment is very scarce. The need for complete revascularization of the foot may be even more important than in other patients with ischaemic ulcerated diabetic foot because there are a number of factors counteracting healing in these patients. Typically, half of the patients are reported to lose their legs despite open bypass. To control tissue damage and improve chances of ulcer healing, one should understand that early referral to vascular consultation is necessary.

Carotid endarterectomy for symptomatic complete occlusion of the internal carotid artery.

We described 9 consecutive patients who underwent operative carotid artery exploration with attempted carotid endarterectomy (CEA) for symptomatic internal carotid artery (ICA) occlusion. Indications for this surgery based on vascular imaging included segmental occlusion of the proximal ICA and also extensive occlusion of the distal ICA in selected patients in whom color-flow duplex ultrasound showed a poorly echogenic or anechoic thrombus with a flow void, suggestive of an acute thrombus. CEA was performed successfully to restore blood flow in all 9 patients:CEA in 5 and CEA with Fogarty thrombectomy in 4. Postoperative magnetic resonance (MR) angiography confirmed that revascularization had been successful in all 9 patients, and MR imaging displayed improved perfusion in 4 patients. Despite the lack of a generalized efficacy of surgical revascularization for symptomatic ICA occlusion, our study demonstrated that preoperative vascular imaging allows the selection of patients who may benefit from CEA.

E-063 Cardiothoracic surgery does not pose significant risk of aneurysmal subarachnoid hemorrhage

ObjectiveNeurologic imaging prior to cardiac surgery often identifies incidental intracranial vascular pathology. The risk of hemorrhage from these lesions during an open cardiothoracic surgical procedure is unknown, preventing appropriate patient...

Fistula Salvage by Endovascular Therapy

Fistulas are considered superior to synthetic grafts as a hemodialysis vascular access; however, fistulas are not without problems. To maximize the number of fistulas being used in prevalent patients, it is important to have a program designed to salvage early failures or fistulas that fail to mature and those that become dysfunctional during the course of usage. Endovascular techniques have proven to be very effective in the management of both of these problems. These fistulas should be aggressively evaluated and treated because treatment carries with it a high expectation of successful salvage of what would have otherwise been an abandoned access.

Preoperative Vascular Evaluation in Living Donor Liver Transplantation for Biliary Atresia

Background Liver transplantation is an important treatment option in the management of end-stage liver disease. Preoperative vascular evaluation plays an important role for a safe and successful operation, especially in pediatric patients undergoing living donor liver transplantation (LDLT). Purpose The purpose of this study is to assess the usefulness and accuracy of Doppler ultrasound (US), computed tomographic angiography (CTA), and magnetic resonance angiography (MRA) in evaluating vascular anomalies in patients with biliary atresia (BA) undergoing LDLT. Methods and Materials Images of Doppler US, CTA, and MRA for preoperative vascular evaluation in 55 patients with BA undergoing LDLT were reviewed with the operative findings. Results All patients underwent preoperative US, CTA, and MRA. Pathologic portal vein (n = 18), interruption of the retrohepatic vena cava (n = 1), and aberrant right hepatic artery from the superior mesenteric artery (n = 2) were confirmed during the transplantation. The success rates of CTA and MRA in identifying vascular anomalies were 96% and 82%, respectively ( P = .01). The sensitivity, specificity, and accuracy of Doppler US were 89%, 94%, and 92%, respectively. For CTA, it was 94%, 97%, and 96%, respectively; for MRA (including technical failure), it was 75%, 97%, and 89%, respectively. Conclusion Doppler US serves as an initial assessment for vascular evaluation and has the advantage in determining vascular flow quantities. CTA and MRA are used for precise surgical planning. However, MRA has lower success and accuracy rates when compared with CTA ( P = .01). Doppler US with CTA can provide accurate preoperative vascular imaging in patients with BA undergoing LDLT.

The Value of Preoperative Vascular Imaging in the Selection and Success of Hemodialysis Access

The purpose of this study was to determine the value of preoperative vascular imaging (PVI) in the selection of an arteriovenous fistula (AVF) for hemodialysis with respect to site selection, maturation, patency, and functionality. We retrospectively evaluated 482 AVFs and arteriovenous grafts (AVGs) created in 321 patients who were regularly undergoing hemodialysis at our university's hemodialysis centers. The patients were divided into two groups according to PVI status. The patients in group 1 (n = 260) underwent Doppler ultrasonographic evaluation and venographic studies as well as physical examination before operation. The patients in group 2 (n = 222) underwent only physical examination before operation. Both groups were compared with respect to vascular access type, access maturation rate, and duration of access patency. In group 1, central veins were also evaluated for possible stenosis, and significant asymptomatic stenosis was treated with interventional techniques. The patients in group 1 were significantly older than those in group 2 and had a significantly higher mean number of previous central venous catheterizations and vascular access sites. At the initiation of the study, 234 of the vascular access sites had matured with a success rate of 90% in group 1. In group 2, however, 152 (68.5%) of the vascular access sites had matured. AVGs of the vascular access type were created in 31.5% of patients in group 1 and in 12.6% of patients in group 2. The mean duration of primary patency in group 1 overall (i.e., AVFs and AVGs) was 14.7 +/- 16.8 months, and the 6-month and 12-month patency rates were 72% and 46%, respectively. The mean duration of primary patency in group 2 overall was 11.9 +/- 9.4 months, and the 6-month and 12-month patency rates were 71% and 41%, respectively. Patients in group 1 had a significantly longer mean primary patency time than did those in group 2 (P = 0.024). Sixty-six cases of central vein stenosis were detected during PVI studies and treated interventionally. After those interventions, 38 AVFs and 28 AVGs were created, and all matured sufficiently without exception. As an adjunct to physical examination, PVI evaluations (venography, Doppler ultrasonography) can be used to determine the likelihood of the maturation of vascular access sites and can reveal problems such as central vein stenosis, which can then be treated promptly with percutaneous intervention. In patients with end-stage renal disease, these interventions should lead to a decrease in morbidity and mortality and improved quality of life.

Devascularizing Complications of Free Fibula Harvest: Peronea Arteria Magna

The authors present a case report of devascularizing complications following free fibula harvest. A retrospective review of 93 consecutively imaged limbs demonstrated a peronea arteria magna (PAM) prevalence of 5.3 percent in an urban population, which was used to perform a cost-effectiveness analysis for preoperative vascular imaging of the donor limb using magnetic resonance angiography (MRA) and traditional angiography (TA). Donor-site complications of fibula harvest range from 15 to 30 percent, but are rarely limb-threatening. Limb loss is a dreaded complication of congenital PAM, which can be present with a normal vascular exam. Some microsurgery groups advocate using no preoperative imaging of the donor limb; they rely on intraoperative assessment of the vascular anatomy. An aborted harvest due to aberrant anatomy leads to both direct and indirect added costs. The authors believe that MRA imaging of the donor limb, being minimally invasive, is cost-effective and indicated for free fibula transfers. For equivocal results, conversion to more invasive and costly TA may be necessary.

Preoperative vascular imaging in pediatric liver transplantation

Background/Purpose There is a considerable variation in the use of vascular imaging techniques in the preoperative assessment of children scheduled for liver transplantation. Duplex Doppler ultrasound scan (US), magnetic resonance angiography (MRA), and conventional angiography are used to varying extents. The authors compared the results of preoperative vascular imaging studies with operative findings to determine their accuracy and usefulness. Methods Results of preoperative vascular imaging in 37 consecutive children undergoing cadaveric liver transplantation were compared with operative findings. Those undergoing relatively elective transplantations were investigated by US and MRA (group 1), whereas those requiring urgent transplants were assessed only by US (group 2). Results The median age of the cohort (15 boys; 22 girls) was 4 years (19 days to 16 years) and the median weight was 17 kg (2.9 to 82 kg). In group 1 (n = 26), 20 children had a normal-caliber, patent portal vein at transplant and 6 had a narrow but patent portal vein requiring venous reconstruction in 4. The sensitivity and specificity of MRA in the detection of an abnormally narrow portal vein were 100% (6/6) and 95% (19/20), respectively. If reversed or absent flow in the portal vein on US was taken as an indication of a potentially abnormal vein, the sensitivity and specificity of Doppler US were 83% (5/6) and 95% (19/20), respectively. Magnetic resonance angiography revealed arterial anomalies in 4 children but failed to detect small accessory hepatic arteries in 5. The single patient with an aberrant vena cava was identified by MRA. In group 2 (n = 11), venous findings at operation and on US were concordant in 10 (91%) cases; one infant with reversed flow in the portal vein on US had a thrombosed vein at surgery. Magnetic resonance angiography was useful in 2 patient groups: those with reversed flow on Doppler US or suspected portal vein thrombosis in whom an abnormal portal vein was present in 86% (6/7) and infants with the biliary atresia splenic malformation syndrome who had multiple venous and arterial anomalies. Conclusions A detailed Doppler examination of the hepatic vasculature by an experienced sonographer/radiologist provides sufficient vascular imaging for most children scheduled for cadaveric liver transplantation. Routine MRA is recommended in children with the biliary atresia splenic malformation syndrome and in those with abnormal duplex Doppler US findings. Although there are limited data in this study, MRA is also valuable in children with Budd-Chiari syndrome, liver tumors, or a previous portosystemic shunt.

Remodeling of saccular cerebral artery aneurysm wall is associated with rupture: histological analysis of 24 unruptured and 42 ruptured cases.

The cellular mechanisms of degeneration and repair preceding rupture of the saccular cerebral artery aneurysm wall need to be elucidated for rational design of growth factor or drug-releasing endovascular devices. Patient records, preoperative vascular imaging studies, and the snap-frozen fundi resected after microsurgical clipping from 66 aneurysms were studied. Immunostainings for markers of smooth muscle cell (SMC) phenotype, proliferation, and inflammatory cell subtypes and TUNEL reaction were performed. Unruptured (24) and ruptured (42) aneurysms had similar dimensions (median diameter in unruptured 6 mm; median in ruptured 7 mm; P=0.308). We identified 4 basic types of aneurysm wall that associated with rupture: (1) endothelialized wall with linearly organized SMCs (17/66; 42% ruptured), (2) thickened wall with disorganized SMCs (20/66; 55% ruptured), (3) hypocellular wall with either myointimal hyperplasia or organizing luminal thrombosis (14/66; 64% ruptured), and (4) an extremely thin thrombosis-lined hypocellular wall (15/66; 100% ruptured). Apoptosis, de-endothelialization, luminal thrombosis, SMC proliferation, and T-cell and macrophage infiltration associated with rupture. Furthermore, macrophage infiltration associated with SMC proliferation, and both were increased in ruptured aneurysms resected <12 hours from rupture, suggesting that these were not just reactive changes. Before rupture, the wall of saccular cerebral artery aneurysm undergoes morphological changes associated with remodeling of the aneurysm wall. Some of these changes, like SMC proliferation and macrophage infiltration, likely reflect ongoing repair attempts that could be enhanced with pharmacological therapy.

Multi-slice spiral CT of living-related liver transplantation in children: pictorial essay.

In pediatric living-related liver transplantation, preoperative evaluation of the recipient is important for surgical planning, while the accurate diagnosis of postoperative complications is essential for graft salvage. Multiplanar and three-dimensional imaging using multi-slice spiral CT can be used for preoperative vascular imaging, as well as for evaluating postoperative complications. In this essay, we describe the usefulness of multi-slice CT, combined with a variety of different reconstruction techniques, for the preoperative evaluation of transplant recipients. In addition, we demonstrate the multi-slice CT findings of postoperative complications, including vascular stenosis or thrombosis, bile duct leak or stricture, and extrahepatic fluid collection.