Analysis of the Final DENALI Trial Data: A Prospective, Multicenter Study of the Denali Inferior Vena Cava Filter

PURPOSE

To report the final 2-year data on the efficacy and safety of a nitinol retrievable inferior vena cava (IVC) filter for protection against pulmonary embolism (PE).

MATERIALS AND METHODS

This was a prospective multicenter trial of 200 patients with temporary indications for caval filtration who underwent implantation of the Denali IVC filter. After filter placement, all patients were followed for 2 years after placement or 30 days after filter retrieval. The primary endpoints were technical success of filter implantation in the intended location and clinical success of filter placement and retrieval. Secondary endpoints were incidence of clinically symptomatic recurrent PE, new or propagating deep vein thrombosis (DVT), and filter-related complications including migration, fracture, penetration, and tilt.

RESULTS

Filter placement was technically successful in 199 patients (99.5%). Filters were clinically successful in 190 patients (95%). The rate of PE was 3% (n = 6), with 5 patients having a small subsegmental PE and 1 having a lobar PE. New or worsening DVT was noted in 26 patients (13%). Filter retrieval was attempted 125 times in 124 patients and was technically successful in 121 patients (97.6%). The mean filter dwell time at retrieval was 200.8 days (range, 5-736 d). There were no instances of filter fracture, migration, or tilt greater than 15° at the time of filter retrieval or during follow-up.

CONCLUSIONS

The Denali IVC filter exhibited high success rates for filter placement and retrieval while maintaining a low complication rate in this clinical trial.

Tumor Growth Kinetics and Oncologic Outcomes of Patients Undergoing Active Surveillance for Residual Renal Tumor following Percutaneous Thermal Ablation

PURPOSE

To evaluate growth kinetics and oncologic outcomes of patients with renal tumors undergoing active surveillance (AS) for residual viable tumor following percutaneous ablation.

MATERIALS AND METHODS

Following percutaneous thermal ablation, residual tumor was detected in 21/133 (16%) patients on initial follow-up imaging, and AS was undertaken in 17/21 (81%) patients. Initial tumor volumes and volumes after ablation were assessed from cross-sectional imaging to calculate volumetric growth rate (VGR) and volume doubling time (VDT) of residual tumor. The rate of metastasis, overall survival, and renal cell carcinoma (RCC)-specific survival were compared between patients in the AS group and in the routine follow up group of patients who did not have residual tumor.

RESULTS

Median tumor volume prior to ablation, after first ablation, and at final follow-up were 25 cm(3), 6 cm(3), and 6 cm(3), respectively, in patients with residual tumor. Stable, mild, and moderate VGR occurred in 8/17 (47%), 4/17 (24%), and 5/17 (29%) cases, respectively. The 4 cases with fastest VDT underwent delayed intervention with ablation (n = 1) and nephrectomy (n = 3) without subsequent residual, recurrence, or metastasis. There was no significant difference in the rates of RCC metastasis, overall survival, or RCC-specific survival between AS and routine follow-up groups. Metastatic RCC and subsequent death occurred in 1 patient in the AS group, after the patient had refused offers for retreatment for local progression over 60.7 months of follow-up.

CONCLUSIONS

In cases when patients are not amenable to further intervention, AS of residual tumor may be an acceptable alternative and allows for successful delayed intervention when needed.

Percutaneous biliary drainage effectively lowers serum bilirubin to permit chemotherapy treatment

PURPOSE

For digestive tract cancers, the bilirubin threshold for administration of systemic chemotherapy can be 5 or 2 mg/dL (85.5 or 34.2 μmol/L) depending upon the regimen. We examined the ability of percutaneous biliary drainage (PBD) in patients with malignant biliary obstruction to achieve these clinically relevant endpoints.

METHODS

106 consecutive patients with malignant biliary obstruction and a baseline serum bilirubin >2 mg/dL underwent PBD. Time to achieve a bilirubin of 5 mg/dL (85.5 μmol/L), 2 mg/dL (34.2 μmol/L), and survival was estimated by Kaplan-Meier analysis. Potential technical and clinical prognostic factors were subjected to univariate and multivariate analysis. Categorical variables were analyzed by the log rank test. Hazard ratios were calculated for continuous variables.

RESULTS

Median survival was 100 days (range 1-3771 days). Among 88 patients with a pre-drainage bilirubin >5 mg/dL, 62% achieved a serum bilirubin ≤5 mg/dL within 30 days and 84% within 60 days, median 21 days. Among 106 patients with a pre-drainage bilirubin >2 mg/dL, 37% achieved a serum bilirubin ≤2 mg/dL by 30 days and 70% within 60 days, median 43 days. None of the technical or clinical factors evaluated, including pre-drainage bilirubin, were significant predictors of time to achieve a bilirubin ≤2 mg/dL (p = 0.51). Size and type of biliary device were the only technical variables found to affect time to bilirubin of 5 mg/dL (p = 0.016).

CONCLUSION

PBD of malignant obstruction achieves clinically relevant reduction in serum bilirubin in the majority of patients within 1-2 months, irrespective of the pre-drainage serum bilirubin, sufficient to allow administration of systemic chemotherapy. However, the decision to undergo this procedure for this indication alone must be considered in the context of patients' prognosis and treatment goals.

Complication and Readmission Rates following Same-Day Discharge after Percutaneous Renal Tumor Ablation

PURPOSE

To evaluate readmission rate and complications in patients undergoing same-day discharge following percutaneous thermal ablation of renal tumors.

MATERIALS AND METHODS

Patients undergoing same-day discharge following thermal ablation of renal tumors were reviewed. The primary outcome was the rate of readmission within 30 days of same-day discharge. The secondary outcomes included the rate and clinical outcomes of periprocedural complications.

RESULTS

Same-day discharge occurred in 166/174 patients (95%), of whom 2/166 (1%) required short-term readmission due to pulmonary embolism and acute-on-chronic kidney injury. Both patients recovered without permanent morbidity. Admission due to complications occurred in 8/174 (5%) cases, the majority of which were related to hemorrhage. No significant differences in rates of complications or admission were found between cryoablation and RF ablation. Major complications (Clavien-Dindo grade II or higher, SIR grade C or higher) occurred in 7/174 (4%) cases, the majority related to hemorrhage. All cases were detected in the standard 4 hour postprocedural observation period and managed conservatively. The mean hemorrhage volume was significantly larger in patients requiring admission versus those discharged the same day (289 mL vs 34 mL; P = .02). Higher-volume hemorrhage occurred in larger tumors (mean, 4.0 cm vs 3.0 cm; P = .04). There was no association between major complications and central tumor or age.

CONCLUSIONS

Routine same-day discharge following percutaneous renal tumor thermal ablation can be performed with a low rate of short-term readmission. The majority of periprocedural complications can be managed conservatively, and patients can be discharged the same day.

Match day: online search trends reflect growing interest in IR training

Google Trends was used to characterize the relationship between the interventional radiology (IR) applicant pool and related Internet queries for "IR fellowship" from July 2006 to July 2013. Results were compared with National Residency Match Panel data by regression analysis and one-way analysis of variance. Search traffic for IR fellowship demonstrated a statistically significant linear annual increase (R(2) = 0.87; P = .0013). Total IR applicants increased by 184% (R(2) = 0.98; P = .0216). Search traffic was predictive of applicants for each match year (R(2) = 0.92; P = .0004) and programs filled (R(2) = 0.93; P = .0003). Internet queries mirror trainee professional interests, with significant increases in search traffic related to IR fellowship and strong correlation with growth in applicants.

Management of Endoleaks

The management of endoleaks remains an inherent challenge to endovascular aneurysm repair (EVAR), particularly as evolving techniques and devices have allowed treatment of increasingly complex aneurysm anatomy. Endovascular techniques are the favored modality for endoleak repair and include techniques to bridge the endoleak defector and embolize the endoleak nidus and inflow/outflow vessels. Conversion to surgical repair remains the definitive option in cases where less invasive methods have failed or are precluded. In this article, the authors review evidence on the indications, approach, and outcomes of current techniques for endoleak management.

Long-Term Patency and Clinical Analysis of Expanded Polytetrafluoroethylene-Covered Transjugular Intrahepatic Portosystemic Shunt Stent Grafts

PURPOSE

To evaluate long-term patency and symptomatic recurrence rates following transjugular intrahepatic portosystemic shunt (TIPS) creation with expanded polytetrafluoroethylene (ePTFE)-covered stent grafts and to determine the necessity of extended clinical follow-up beyond 2 years after TIPS creation.

MATERIALS AND METHODS

A retrospective review including 262 TIPSs created with ePTFE-covered stent grafts between July 2002 and October 2012 was performed. Primary, primary assisted, and secondary patency rates were calculated. Assessment of clinical data included technical, hemodynamic, and clinical success rates, as well as mortality after TIPS creation.

RESULTS

Primary patency rates at 2, 4, and 6 years were 74%, 62%, and 50%, respectively. Primary assisted patency rates at 2, 4, and 6 years were 93%, 85%, and 78%, respectively. Secondary patency rates at 2, 4, and 6 years were 99%, 91%, and 84%, respectively. Technical and hemodynamic success rates were 99% and 93%, respectively. Clinical success rates for refractory ascites were 66% (complete response) and 90% (partial response); clinical success rate for bleeding/varices was 90%. Mortality rates at 2, 4, and 6 years after TIPS creation were 27%, 38%, and 46%, respectively. At the median wait time until transplantation, patients had an 84% chance of being alive. TIPS dysfunction developed in 21% of patients; 30% of revisions occurred later than 2 years during follow-up.

CONCLUSIONS

Beyond 2 years after TIPS creation, patency rates gradually decrease, mortality rates continue to increase, and the chance of recurrent ascites or bleeding remains present. Together, these findings suggest that continued clinical follow-up beyond 2 years is necessary in patients with a TIPS created with an ePTFE-covered stent graft.

Long-term outcomes of a benign biliary stricture protocol

PURPOSE

To evaluate long-term outcomes of a structured protocol for percutaneous treatment of benign biliary stricture.

MATERIALS AND METHODS

Seventy-one patients (37 men, 34 women; mean age, 54 y; age range, 23-84 y) entered the protocol, which consisted of staged upsizing of internal/external biliary catheters, balloon dilation (nominally 8 mm), and prolonged stent treatment (6 mo) at maximal catheter size (nominally 18 F). It concluded with a capping trial and catheter removal if the stricture remained patent. Fifty-three patients completed the protocol and 18 did not (6 died, 6 underwent alternative treatment, 4 were lost to follow-up, and 2 underwent repeat transplantation). Stricture features, treatment parameters, complications, and outcomes were reviewed, and Kaplan-Meier analysis was conducted.

RESULTS

Strictures were anastomotic in 45 patients (64%), intrahepatic in 14 (20%), extrahepatic in 7 (10%), and multiple (intra- and extrahepatic) in 5 (7%). A right-sided approach was used in 47 patients (66%) patients, a left-sided approach in 18 (25%), and a bilateral approach in 6 (9%). Forty-six patients who entered the protocol (65%) and 46 patients who completed the protocol (87%) showed stricture patency. Four of 7 patients in whom a capping trial failed underwent surgical revision, 2 required chronic biliary drainage, and 1 received a metal stent. Follow-up (range, 0-12 y; mean, 4.7 y) was obtained for 42 of 53 patients who completed the protocol (79%). Kaplan-Meier analysis showed stricture patency probabilities of 84% at 1 year after treatment, 78% at 2 years, 74% at 5 years, and 67% at 10 years.

CONCLUSIONS

Use of a structured protocol for the percutaneous treatment of benign biliary strictures yields durable long-term results, suggesting that percutaneous treatment is an effective therapy.

The DENALI Trial: an interim analysis of a prospective, multicenter study of the Denali retrievable inferior vena cava filter

PURPOSE

To assess safety and effectiveness of a nitinol retrievable inferior vena cava (IVC) filter in patients who require caval interruption to protect against pulmonary embolism (PE).

MATERIALS AND METHODS

Two hundred patients with temporary indications for an IVC filter were enrolled in this prospective, multicenter clinical study. Patients undergoing filter implantation were to be followed for 2 years or for 30 days after filter retrieval. At the time of the present interim report, all 200 patients had been enrolled in the study, and 160 had undergone a retrieval attempt or been followed to 6 months with their filter in place. Primary study endpoints included technical and clinical success of filter placement and retrieval. Patients were also evaluated for recurrent PE, new or worsening deep vein thrombosis, and filter migration, fracture, penetration, and tilt.

RESULTS

Clinical success of placement was achieved in 94.5% of patients (172 of 182), with a one-sided lower limit of the 95% confidence interval of 90.1%. Technical success rate of filter placement was 99.5%. Technical success rate of retrieval was 97.3%; 108 filters were retrieved in 111 attempts. In two cases, the filter apex could not be engaged with a snare, and one device was engaged but could not be removed. Filter retrievals occurred at a mean indwell time of 165 days (range, 5-632 d). There were no instances of filter fracture, migration, or tilt greater than 15° at the time of retrieval or 6-month follow-up.

CONCLUSIONS

In this interim report, the nitinol retrievable IVC filter provided protection against pulmonary embolism, and the device could be retrieved with a low rate of complications.

Outcomes of percutaneous interventions in transposed hemodialysis fistulas compared with nontransposed fistulas and grafts

PURPOSE

To compare postpercutaneous intervention outcomes of autogenous venous-transposition arteriovenous fistulas (AVFs) versus those of autogenous nontransposed AVFs (nAVFs) and prosthetic arteriovenous grafts (AVGs).

MATERIALS AND METHODS

A total of 591 hemodialysis accesses (195 transposed AVFs [tAVFs], 205 nAVFs, 191 AVGs) in 522 patients (278 male; mean age, 57 y; range, 15–91 y) underwent percutaneous transluminal angioplasty (PTA) and/or mechanical thrombectomy (ie, declotting). Access characteristics, surgical history, percutaneous interventions, postinterventional primary and secondary access patency, and follow-up data were collected. Cox proportional-hazards regression analyses, Fisher exact tests, and χ2 tests were performed.

RESULTS

Mean follow-up period was 32 months. Mean access ages at initial percutaneous intervention were 260 days (tAVF), 206 days (nAVF), and 176 days (AVG; P < .01). One-year postinterventional primary patency (PIPP) rates were 25% (tAVF), 24% (nAVF), and 14% (AVG). One-year postinterventional secondary patency (PISP) rates were 77% (tAVF), 61% (nAVF), and 63% (AVG). Median PIPP durations were 138 days (tAVF), 121 days (nAVF), and 79 days (AVG; P = .0001). Median PISP durations were 1,076 days (tAVF), 783 days (nAVF), and 750 days (AVG; P = .019). Total interventions needed to maintain PISP were 2.4 (tAVF), 1.3 (nAVF), and 3.2 (AVG) per patient-year (P < .001), which included 1.9, 1.2, and 1.4 PTAs (P < .01) and 0.45, 0.15, and 1.8 declotting procedures, respectively (P < .001).

CONCLUSIONS

Based on the number of percutaneous interventions needed to maintain PISP, these results confirm the current Dialysis Outcomes Quality Initiative access preference of nAVFs before tAVFs before AVGs. tAVFs offered superior postinterventional outcomes than AVGs. With additional interventions, tAVFs could even outperform nAVFs in terms of PISP.

Comparison of polyvinyl alcohol microspheres and tris-acryl gelatin microspheres for uterine fibroid embolization: results of a single-center randomized study

PURPOSE

To assess the efficacy of two embolic agents in the treatment of symptomatic uterine leiomyomas.

MATERIALS AND METHODS

A randomized, prospective, single-center study enrolled 60 women with symptomatic uterine leiomyomas. Uterine artery embolization (UAE) with spherical polyvinyl alcohol (SPVA) microspheres (n = 30; 700-900 μm and 900-1,200 μm; near-stasis or stasis endpoint) and tris-acryl gelatin (TAG) microspheres (n = 30; 500-700 μm; "pruned-tree" endpoint) was performed. Infarction rates were calculated for the dominant tumor and for small (< 2 cm) and large (> 2 cm) nondominant tumors. The primary endpoint was tumor infarction at 24 hours measured by contrast-enhanced magnetic resonance imaging assessed by a blinded reviewer.

RESULTS

Baseline characteristics were similar between groups. The primary endpoint was similar in both treatments (≥ 91% dominant tumor infarction; SPVA. 86.2%; TAG, 93.3%, P = .35). Complete infarction (100%) was also similar between arms at 24 hours and 3 months. Symptom severity was reduced and quality of life improved equally at 3 and 12 months in each treatment group. Complications were minor in both groups.

CONCLUSIONS

Uterine leiomyoma infarction at 24 hours and 3 months after treatment with SPVA or TAG microspheres was comparable when using near-stasis as a procedural endpoint with SPVA microspheres. Symptom relief was maintained for as long as 12 months for both embolic agents.

Chest radiograph-based algorithm for managing malfunctioning ports

PURPOSE

To evaluate a chest x-ray-based algorithm for managing malfunctioning ports.

MATERIALS AND METHODS

A review of interventional radiology procedures on malfunctioning ports during the period 2000-2012 was performed. Events were divided into two periods: before and after implementation of an algorithm beginning with tip position evaluation using a chest x-ray. Time to return to usability, frequency of interventions to restore function, and frequency of malfunctioning ports remaining in use after the procedure were calculated.

RESULTS

The review included 303 procedures before implementation of the algorithm on 237 access sites in 227 patients (mean age, 56 y; 38% male) and 155 procedures after implementation of the algorithm on 131 access sites in 130 patients (mean age, 55 y; 35% male). Implementation of the algorithm was associated with significantly fewer repeat checks on the same access (27% before algorithm, 9% after algorithm, P < .001) and reduced frequency of a malfunctioning port remaining in use after the interventional radiology procedure (43% before algorithm to 14% after algorithm, P < .001). Median time from consultation to revision was significantly less after implementing the algorithm (13 days before algorithm, 1 day after algorithm, P < .001). Median time from consultation to port usability was also less after implementing the algorithm (2.7 days before algorithm, 1 day after algorithm, P < .001).

CONCLUSIONS

Implementation of the algorithm was associated with significantly less frequent repeat procedures on the same port and a lower frequency of malfunctioning ports remaining in place. Use of the algorithm was associated with significantly reduced time from consultation to revision and to return to usability. These findings suggest the algorithm allows triage of patients with malfunctioning ports to the appropriate intervention before undergoing a procedure.

Improving retrieval rates for retrievable inferior vena cava filters

The introduction of retrievable inferior vena cava (IVC) filters was an important step in the evolution of deep vein thrombosis/pulmonary embolism management. Their removability makes them preferred to permanent filters in many cases. IVC filter retrieval often occurs at a suboptimal rate, leading to complications associated with long-term placement. Improving retrievability includes solutions for patients being lost to follow-up, filter malpositioning, need arising for permanent IVC filtration, filtration requiring longer than the filter's window of retrievability, and filter compromise by the presence of a large trapped clot. This review explores these strategies for retrieval in detail in hopes of improving IVC filter retrieval rates.

Objective and subjective assessment of physician labor and resource utilization in maintenance percutaneous transluminal angioplasty of nonthrombosed hemodialysis arteriovenous fistulas versus arteriovenous grafts

PURPOSE

To complement prior studies that have shown that arteriovenous fistula (AVF) thrombectomies require more time and equipment than arteriovenous graft (AVG) thrombectomies by measuring work via established instruments to determine whether there is also a difference in maintenance percutaneous transluminal angioplasty (PTA) of nonthrombosed AVFs versus AVGs.

MATERIALS AND METHODS

PTA procedures performed on a consecutive cohort of 42 patients with AVFs and 27 patients with AVGs were prospectively compared. To quantify resource utilization, procedure time and disposable equipment were measured. Established instruments developed by the American Medical Association for Current Procedural Terminology code valuation were used to measure subjective "physician work," including mental effort and judgment, technical skill, physical effort, and psychological stress. These items were scored by 1 of 12 attending interventional radiology physicians performing the procedure.

RESULTS

Mean PTA procedure time was 74 minutes (range, 18-183 minutes) for AVFs and 71 minutes (range, 28-204 minutes) for AVGs; hemostasis time was 12 minutes for AVFs and 11 minutes for AVGs. There was no significant difference in equipment use between groups. "Physician work" for AVFs scored significantly higher in four categories (P≤ .05).

CONCLUSIONS

Using established subjective instruments, maintenance PTA of AVFs was scored as more cognitively, physically, and psychologically demanding than maintenance PTA of AVGs. However, there was no significant difference in resource utilization between maintenance PTA of AVFs versus AVGs, as has been previously shown with thrombectomy of thrombosed AVFs and AVGs.

Inferior vena cava filters for primary prophylaxis: when are they indicated?

Over the past several years there has been a rapid increase in the number of inferior vena cava (IVC) filters placed for primary thromboprophylaxis. Increased use has occurred in settings where other methods of thromboprophylaxis are viewed to be inadequate, technically challenging, or that place patients at an unacceptably high bleeding risk. These clinical services include trauma, bariatric surgery, neurosurgery, cancer, intensive care unit populations, and patients with a relative contraindication to anticoagulation. We review the studies to date addressing filter placement for these indications. Although preliminary data are promising, the patient populations most likely to benefit from prophylactic IVC filter placement have not been well defined, and randomized studies demonstrating efficacy have not been conducted. Moving forward, it will be critical to accomplish these two tasks if IVC filters are to continue to have a role in primary thromboprophylaxis.

Impact on renal function of percutaneous thermal ablation of renal masses in patients with preexisting chronic kidney disease

PURPOSE

To examine the effect of percutaneous thermal ablation of renal masses on renal function among patients with baseline chronic kidney disease (CKD).

MATERIALS AND METHODS

Patients with baseline CKD (initial glomerular filtration rate [GFR] < 60 mL/min/1.73 m(2)) who underwent percutaneous cryoablation or radiofrequency (RF) ablation of renal masses were reviewed.

RESULTS

A total of 48 patients with a GRF of 60 mL/min/1.73 m(2) or lower were treated with renal cryoablation or RF ablation and had follow-up GFR measurement 1 month afterward. Mean patient age was 73 years (range, 47-89 y). Cryoablation was performed in 22 patients and RF ablation was performed in 26. Mean tumor diameter was 3.4 cm (range, 0.9-10.2 cm). Mean overall GFRs were 39.8 mL/min/1.73 m(2) at baseline and 39.7 mL/min/1.73 m(2) at 1 month after ablation (P = .85). A total of 38 patients had 1-year follow-up GFR measurement (cryoablation, n = 18; RF ablation, n = 20), and their mean GFR was 40.9 mL/min/1.73 m(2) ± 11.4 (SD), compared with a preablation GFR of 41.2 mL/min/1.73 m(2)(P = .79). In the cryoablation group, mean GFRs at 1 month and 1 year were 41.4 mL/min/1.73 m(2) and 44.4 mL/min/1.73 m(2), compared with respective baseline GFRs of 41.1 mL/min/1.73 m(2) and 42.1 mL/min/1.73 m(2) (P = .75 and P = .19, respectively). In the RF ablation group, mean GFRs at 1 month and 1 year were 38.2 mL/min/1.73 m(2) and 37.8 mL/min/1.73 m(2), compared with respective baseline GFRs of 38.7 mL/min/1.73 m(2) and 40.4 mL/min/1.73 m(2) (P = .58 and P = .09, respectively).

CONCLUSIONS

Independent of ablation modality, percutaneous renal mass ablation does not appear to affect renal function among patients with CKD.