Fostering research in pediatric interventional radiology: needs assessment and suggestions for support

BACKGROUND

Due to the rarity of pediatric diseases, collaborative research is the key to maximizing the impact of research studies. A research needs assessment survey was created to support initiatives to foster pediatric interventional radiology research.

OBJECTIVE

To assess the status of pediatric interventional radiology research, identify perceived barriers, obtain community input on areas of research/education/support, and create metrics for evaluating changes/responses to programmatic initiatives.

MATERIALS AND METHODS

A survey link was sent to approximately 275 members of the Society for Pediatric Interventional Radiology (SPIR) between May and October 2020. Data was collected using a web-based interface. Data collected included practice setting, clinical role, research experience, research barriers, and suggestions for future initiatives.

RESULTS

Fifty-nine surveys were analyzed with a staff physician survey response rate of 28% (56/198). A wide range of practice sizes from 15 countries were represented. Respondents were predominantly staff physicians (95%; 56/59) with an average of 11 years (range: 1-25 years) of clinical experience working at academic or freestanding children's hospitals. A total of 100% (59/59) had research experience, and 70% (41/58) had published research with a mean of 30 peer-reviewed publications (range: 1-200). For job security, 56% (33/59) of respondents were expected or required to publish, but only 19% (11/58) had research support staff, and 42% (25/59) had protected research time, but of those, 36% (9/25) got the time "sometimes or never." Lack of support staff, established collaborative processes, and education were identified as top barriers to performing research.

CONCLUSIONS

The needs assessment survey demonstrated active research output despite several identified barriers. There is a widespread interest within the pediatric interventional radiology community for collaborative research.

Giant Congenital Melanocytic Nevus Treated With Trametinib

Giant congenital nevi are melanocytic proliferations of the skin that may be complicated by melanoma, neurocutaneous melanocytosis, pain, pruritus, and disfigurement. Current treatment options include surgical resection and medical management of associated symptoms. There is limited efficacy in these modalities. No effective pharmacologic treatments are available for the treatment of these lesions. We present the case of a 7-year-old girl with a giant congenital melanocytic nevus that had an AKAP9-BRAF fusion and was treated with trametinib, which resulted in rapid resolution of the patient's lifelong, intractable pain and pruritus as well as dramatic improvement in the extent of her nevus.

Improving the tracking and removal of retrievable inferior vena cava filters

Therapeutic and prophylactic inferior vena cava (IVC) filters should be placed based on currently accepted indications to prevent a fatal pulmonary embolism (PE). The protective effect of filters is offset by the potential for lower extremity deep venous thrombosis (DVT), caval thrombosis, and possible otherwise unnecessary life-long anticoagulation (AC). The duration of treatment for most DVTs or PEs is 3 to 6 months of AC/filter. Filters should be retrieved when duration of treatment for a DVT/PE has been met, the risk of a PE is no longer high, and/or there is no longer a contraindication to AC. An effective system that leads to improving the retrieval rate of filters must include education of the patient, a tracking system to minimize patient lost to follow-up, and dedicated personnel to oversee the process. If these goals are accomplished, interventionalists can help decrease the incidence of a fatal PE during the high-risk period, and also decrease the risk of a DVT or the use of otherwise unnecessary life-long AC in subsequent years. Currently, there is much room for improvement in the frequency that IVCF patients are systematically followed and filters are retrieved. The principles discussed in this report will be helpful in this process.

A policy of dedicated follow-up improves the rate of removal of retrievable inferior Vena Cava Filters in trauma patients

Retrievable Inferior Vena Cava Filters (IVCF) for prophylaxis against pulmonary embolus have been associated with low rates of removal. Strategies for improving the rates of retrieval have not been described. We hypothesized that a policy of dedicated follow-up would achieve a higher rate of filter removal. Trauma and Nontrauma patients who had a retrievable IVCF placed during 2006 were identified. A protocol existed for trauma patients with chart stickers, arm bracelets, and dedicated follow-up by nurse practitioners from three trauma teams. No protocol existed for nontrauma patients. Statistical analysis was performed using χ(2) analysis or analysis of variance. One hundred sixty-seven retrievable IVCFs were placed over 12 months; 91 in trauma patients and 76 in nontrauma patients. Trauma patients were more likely to have their IVCF removed than nontrauma patients, 55 per cent versus 19 per cent, P < 0.001. There were differences between the three trauma teams, with removal rates of 44 per cent, 42 per cent, and 86 per cent respectively (P < 0.05). On multivariate analysis young age and trauma patient status were independent predictors of filter removal. A policy of dedicated follow-up of patients with IVCFs can achieve significantly higher rates of filter removal than have been previously reported. Similar policies should be adopted by all centers placing retrievable IVCFs to maximize retrieval rates.

A Policy of Dedicated Follow-Up Improves the Rate of Removal of Retrievable Inferior Vena Cava Filters in Trauma Patients

Retrievable Inferior Vena Cava Filters (IVCF) for prophylaxis against pulmonary embolus have been associated with low rates of removal. Strategies for improving the rates of retrieval have not been described. We hypothesized that a policy of dedicated follow-up would achieve a higher rate of filter removal. Trauma and Nontrauma patients who had a retrievable IVCF placed during 2006 were identified. A protocol existed for trauma patients with chart stickers, arm bracelets, and dedicated follow-up by nurse practitioners from three trauma teams. No protocol existed for nontrauma patients. Statistical analysis was performed using χ2 analysis or analysis of variance. One hundred sixty-seven retrievable IVCFs were placed over 12 months; 91 in trauma patients and 76 in nontrauma patients. Trauma patients were more likely to have their IVCF removed than nontrauma patients, 55 per cent versus 19 per cent, P < 0.001. There were differences between the three trauma teams, with removal rates of 44 per cent, 42 per cent, and 86 per cent respectively ( P < 0.05). On multivariate analysis young age and trauma patient status were independent predictors of filter removal. A policy of dedicated follow-up of patients with IVCFs can achieve significantly higher rates of filter removal than have been previously reported. Similar policies should be adopted by all centers placing retrievable IVCFs to maximize retrieval rates.

What we still do not know about adrenal vein sampling for primary aldosteronism

During the last two decades, primary aldosteronism has emerged as the most common cause of secondary hypertension, and advances in the diagnosis and treatment of this condition have improved patient care substantially. A major stumbling block in the evaluation and management of these patients, which ultimately guides treatment and prognosis, is answering the question, "Which adrenal gland(s) produce aldosterone?" Adrenal vein sampling has emerged as the only reliable method to determine the answer to this question; however, the methodology and criteria for lateralization have been determined empirically with little prospective data. The major remaining controversies surrounding adrenal vein sampling include: who should perform and who should undergo the procedure; what criteria should be used to define a successful study and lateralization of aldosterone production; whether cosyntropin should be infused during the procedure and how; and what to do when results are ambiguous? This article reviews some of the advances in the execution of this procedure, the variations in procedure, the data that fuel the controversies, and the issues that need to be resolved in the future.

Obstetric and gynecologic emergencies: a review of indications and interventional techniques

There are many interventional techniques that can be used to aid the obstetrician or gynecologist in caring for their patients in the acute setting. Embolization can be life saving in the case of postpartum hemorrhage. Bleeding related to cervical cancer or the threat of bleeding from cervical ectopic pregnancy is amenable to embolization as is hemorrhage related to uterine arteriovenous malformations. Postpartum women are also at a uniquely high risk for deep vein thrombosis and pulmonary emboli and may benefit from consultation and treatment by an interventional radiologist. The goal of this article is to discuss the valuable role that the interventional radiologist plays in the treatment of these obstetric and gynecologic conditions.

Techniques in interventional radiology: renal CT angiography

Multidetector row CT angiography has become an important tool in the evaluation of patients with suspected renovascular hypertension. The following article presents a review of the published data on accuracy of this method of evaluation as well as a comparison to other diagnostic strategies, in particular, renal MR angiography.

Measurement of 18-hydroxycorticosterone during adrenal vein sampling for primary aldosteronism

CONTEXT

In primary aldosteronism, elevated serum 18-hydroxycorticosterone (18OHB) suggests aldosterone-producing adenoma (APA) rather than bilateral, idiopathic hyperaldosteronism (IHA), but little is known about the relative production of 18OHB and aldosterone (A) in APAs compared with IHA.

OBJECTIVES

We measured 18OHB, A, and cortisol (F) in blood from adrenal vein sampling (AVS) studies. We compared the discriminatory power of gradients in 18OHB/A and 18OHB/F ratios with A/F ratio gradients for distinguishing APA from IHA.

DESIGN, SETTING, AND SUBJECTS

We measured 18OHB and A in excess serum from 23 AVS studies performed at our university hospitals.

MAIN OUTCOME MEASURES

We calculated the ratios 18OHB/A, 18OHB/F, and A/F for all specimens, and determined the adrenal vein gradients for these ratios.

RESULTS

The 18OHB/A ratios were much lower in blood draining APAs (2.17 +/- 0.62) than in blood draining the contralateral adrenals (12.96 +/- 12.76; P < 0.001) but similar to blood draining IHA adrenals (4.69 +/- 4.32; P = 0.02). In contrast, the 18OHB/F ratios were elevated in specimens from APAs (26.03 +/- 11.51) compared with IHA adrenals (9.22 +/- 5.18; P < 0.001) or the contralateral adrenals (6.23 +/- 2.97; P < 0.001). Using 18OHB/F gradient greater than two or 18OHB/A gradient less than 0.5 as criteria for lateralization, interpretations agreed with lateralizations based on A/F gradients in 21 of 23 cases.

CONCLUSIONS

High serum 18OHB in APA reflects augmented production of both 18OHB and A, not disproportionate 18OHB secretion relative to A. The 18OHB/A and 18OHB/F gradients are useful adjuncts but not as reliable as A/F gradients for A lateralization during AVS.

Contemporary techniques and safety of cardiovascular procedures in the surgical management of renal cell carcinoma with tumor thrombus

OBJECTIVE

Renal cell carcinomas often form venous thrombi that extend into the vena cava. Frequently, cardiovascular consultation is necessary for complete surgical excision. We sought to investigate the risk factors, surgical techniques, and outcomes of patients treated for renal cell carcinoma with venous extension.

METHODS

We reviewed the records of 46 consecutive patients who underwent surgical management of renal cell carcinoma with venous extension between 1991 and 2005. Data on patient history, staging, surgical techniques, morbidity, and survival were analyzed.

RESULTS

There were 29 men and 17 women with a mean age of 60.2 +/- 12.0 years. Twenty-five (54%) procedures were completed with cardiovascular assistance. Nephrectomy was performed in 44 (96%) cases. Three (7%) patients underwent right heart venovenous bypass, and 2 (5%) patients underwent cardiopulmonary bypass with circulatory arrest. Fourteen (32%) patients had perioperative complications, including 1 (2%) perioperative death. Patients who required cardiovascular procedures (inferior vena cava clamping, right heart venovenous bypass, and cardiopulmonary bypass with circulatory arrest) had higher risks of perioperative complications (P < .02). The 1-, 2-, and 5-year overall survival rates were 78%, 69%, and 56%.

CONCLUSIONS

This large series demonstrates that aggressive treatment of renal cell carcinoma with venous thrombus provides favorable outcomes. Our 5-year survival is among the highest of recent reviews, and our perioperative morbidity and mortality rates are comparable with those of other series. Tumors that require cardiovascular procedures are associated with increased complications when compared with radical nephrectomy and thrombectomy alone. Nevertheless, this aggressive treatment approach offers encouraging patient survival.

Percutaneous radiofrequency ablation of renal tumors: technique, limitations, and morbidity

OBJECTIVES

To evaluate our evolving experience with percutaneous radiofrequency (RF) renal tumor ablation and focus on our technique to ensure maximal treatment efficacy and reduce the possibility of complications.

METHODS

Fifteen patients with small (less than 4 cm) posterior or lateral contrast-enhancing (more than 10 Hounsfield units) renal tumors were candidates for RF treatment. Of these patients, 12 (13 tumors) received computed tomography-guided percutaneous RF ablation. General anesthesia was administered in all but our first 2 patients, who received intravenous sedation. After treatment, patients were closely followed up with computed tomography scans at 6 weeks and 3, 6, and 12 months, and every 6 months thereafter. Successful ablation was defined as a lesion along with a margin of normal parenchyma that no longer enhanced (less than 10 Hounsfield units) on follow-up contrast imaging.

RESULTS

The mean tumor size was 2.4 +/- 0.6 cm. The average procedure time was 95 minutes (range 60 to 150) and length of stay 0.9 days. All patients underwent the procedure without any major complications. At a mean follow-up of 4.9 months, 12 (93%) of 13 tumors were successfully ablated. In 3 patients, the procedure was not performed because of intervening bowel or lung parenchyma when positioned in the prone position before the procedure. Computed tomography-guided percutaneous RF ablation of small renal tumors is a viable minimally invasive treatment option with a high short-term success rate and low morbidity. This new technology must be uniformly applied to assess its long-term efficacy.

Polytetrafluoroethylene-encapsulated stent-grafts: use in experimental abdominal aortic aneurysm

PURPOSE

To evaluate expanded polytetrafluoroethylene (ePTFE) encapsulated stents for the treatment of aortic aneurysms with emphasis on the blood and tissue-material interactions.

MATERIALS AND METHODS

Experimental aortic aneurysms were created in dogs by enlarging the aortic lumen with an abdominal fascial patch. Twenty animals underwent endoluminal repair after allowing the surgically created aneurysm to heal for 2 months prior to transluminal aneurysmal exclusion. The device used consisted of an 8-cm-long ePTFE encapsulated stent graft. The animals were killed in groups at 1 week and at 1, 2.25, 6, and 12 months. Specimens were processed for histologic and luminal surface studies.

RESULTS

Before the animals were killed, aortography demonstrated two thrombosed aortae in the 6-month group and two endoleaks in the 12-month group. Endothelialized neointima extended into the proximal and distal portions of the prosthetic lumen, with minimal cell coverage in the center of the graft. The overall percent surface area covered by endothelialized neointima was 22% +/- 6% at 6 months and 18% +/- 10% by 1 year (P = .75). Histologic examination demonstrated minimal tissue penetration into the ePTFE.

CONCLUSION

Transluminal exclusion of abdominal aortic aneurysms by encapsulated stent-graft is easily accomplished. With this device, tissue coverage and penetration of the stent graft is limited and does not tend to increase with time.