Clinical practice of interventional and cardiovascular radiology: current status, guidelines for resource allocation, future directions

The practices of interventional radiology and interventional neuroradiology are centered on high-quality direct patient care. These subspecialties have long histories of innovative care that has often revolutionized the treatment of disease and illness. More recently, however, this success has brought about competition from former referring physicians as they have gained access to technology and training that will enable them to obtain credentials for procedures that were formerly in the exclusive domain of interventionalists. Unfortunately, many interventional radiologists find themselves ill-equipped to compete for referrals. This is primarily because many interventional radiology practices lack complete clinical practices, which are critically important in facilitating referrals from the nonspecialists. Accordingly, this document details the critical importance of a complete clinical practice and further outlines the steps required to achieve this goal.

Long-term outcome after chemoembolization and embolization of hepatic metastatic lesions from neuroendocrine tumors

OBJECTIVE

Hepatic artery chemoembolization and hepatic artery embolization (HAE) are accepted treatments of patients with hepatic metastasis from neuroendocrine tumors. Long-term outcome data are limited. We present our experience in the use of hepatic artery chemoembolization in the treatment of patients with hepatic metastasis from neuroendocrine tumors.

MATERIALS AND METHODS

Forty-six patients with carcinoid (n = 31) or islet cell (n = 15) tumors were treated. Overall and progression-free survival times starting with the first treatment were calculated. Potential factors affecting survival, including presence of extrahepatic disease and resection of the primary lesion, were analyzed. Relief of symptoms was subjectively determined for tumors with hormonal secretion.

RESULTS

The 46 patients underwent 93 hepatic artery chemoembolization or HAE sessions. The mean overall survival time for the entire group was 1,273 +/- 185 days. The mean overall survival times for the carcinoid (1,255 +/- 163 days) and islet cell tumor (1,311 +/- 403 days) subgroups were similar (p = 0.66). The progression-free survival times for the carcinoid (602 +/- 144 days) and islet cell (501 +/- 107 days) tumor subgroups also were similar (p = 0.72). The survival time of patients without known extrahepatic metastasis (n = 18; 1,571 +/- 291 days) trended toward significance compared with that of patients with known extrahepatic disease (n = 26; 770 +/- 112 days; p = 0.08). Resection of the primary tumor in 19 of 46 patients did not affect survival (resection survival, 1,558 +/- 400 days; nonresection survival, 1,000 +/- 179 days; p = 0.44). Twenty of 25 patients with hormonally active tumors had relief of symptoms after one cycle of treatment. The 30-day mortality was 4.3%.

CONCLUSION

The overall survival time after hepatic artery chemoembolization or HAE among patients with neuroendocrine tumors is approximately 3.5 years. The progression-free survival time approaches 1.5 years. The presence of extrahepatic metastasis or an unresected primary tumor should not limit the use of hepatic artery chemoembolization or HAE.

Hepatic Arterial Chemoembolization for Hepatocellular Carcinoma: Comparison of Survival Rates with Different Embolic Agents

PURPOSE

The optimal embolic agent for transhepatic arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) has not been identified. This study reports outcomes of TACE for HCC with Gelfoam powder and polyvinyl alcohol (PVA).

MATERIALS AND METHODS

Eighty-one patients underwent 152 TACE sessions with Gelfoam powder (n = 41) or polyvinyl alcohol (PVA) and Ethiodol (n = 40) as the embolic agent. Chemotherapeutic drugs were the same for all patients (50 mg cisplatin, 20 mg doxorubicin, 10 mg mitomycin-c). The groups were compared based on number of TACE sessions, maximum tumor size, bilirubin level, aspartate and alanine aminotransferase levels, Child-Pugh score, Model for End-stage Liver Disease score, and hepatitis B or C virus positivity. The number of cases of each Child class in each group was also evaluated. Survival starting from the first TACE session was calculated according to Kaplan-Meier analysis. Forty-eight patients died during the study period, 19 received transplants, and 14 were alive at the end of the study period.

RESULTS

The groups were statistically similar in all categories regarding liver function, Child-Pugh score, tumor size, hepatitis status, and percentage of patients with Child class A, B, and C disease. The number of TACE sessions was significantly greater for the Gelfoam powder group (mean, 2.2) versus the PVA group (mean, 1.6; P = .01). Overall survival was similar between groups whether patients who received transplants were included in the analysis (mean, 659 days +/- 83 with Gelfoam powder vs 565 days +/- 71 with PVA; P = .42) or were excluded (mean, 519 days +/- 80 with Gelfoam powder vs 511 days +/- 75 with PVA; P = .93).

CONCLUSION

In similar patient groups, survival after treatment of HCC with TACE with Gelfoam powder or PVA and Ethiodol was similar.

Effects of Schwann cells and donor antigen on long-nerve allograft regeneration

Nerve allotransplantation has been used successfully in human subjects to restore function after traumatic nerve injury and avoid subsequent limb amputation. However, due to the morbidity associated with nonspecific immunosuppression, this reconstructive approach has been limited to patients with particularly severe nerve injuries. It would be desirable to broaden the indications for such procedures through development of less toxic antirejection therapies. A miniature swine model of nerve transplantation was used to investigate the effects of preoperative ultraviolet-B (UV-B)-irradiated donor alloantigen portal venous infusion and injection of cultured major histocompatibility complex (MHC)-matched Schwann cells into the nerve graft. The transplanted ulnar nerves were harvested at 20 weeks. Histomorphometry showed marked enhancement in nerve regeneration through allografts injected with Schwann cells. Serial mixed lymphocyte assays demonstrated suppression of the recipient immune response to the donor antigen after pretreatment, but no additional neuroregenerative effect of donor alloantigen pretreatment.

Comparison of MELD and Child-Pugh scores to predict survival after chemoembolization for hepatocellular carcinoma

PURPOSE

To compare the value of the Child-Pugh and Model for End-stage Liver Disease (MELD) scores to predict patient survival rates after transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Eighty-seven patients underwent 169 TACE sessions. Child-Pugh and MELD values were calculated before initial treatment. Survival length was tracked from the date of the first TACE procedure. Transplant recipients were censored from the study at the time of surgery. Child-Pugh and MELD scores as well as bilirubin and albumin levels and International Normalized Ratio were placed in high and low categories defined by their respective medians. Patient survival was compared at 3 months, 6 months, 12 months, and 24 months, and patterns were tested with chi2 or Fisher exact tests. Survival over the entire period was examined with Kaplan-Meier analysis and differences were tested with log-rank tests.

RESULTS

Mean and median survival times for all patients were 24 and 17 months, respectively. Sixteen patients were censored for transplantation at a mean of 12.9 months. MELD and Child-Pugh scores correlated well with each other (r = 0.68). Child-Pugh score (r = -0.35, P = .04) correlated more strongly with 12-month survival than did MELD score (r = -0.26, P = .12). After high/low score category division, a significantly greater survival difference was predicted by Child-Pugh score (27.2 months vs 10.3 months; P = .03) versus MELD score (27.5 months vs 15.8 months; P = .19). An albumin level greater than 3.4 g/dL was also associated with significantly improved survival (29.3 months vs 10.1 months; P = .0032). Survival differences between high-risk and low-risk groups at the 3-, 6-, 12-, and 24-month intervals were significant for low Child-Pugh scores and for albumin levels greater than 3.4 g/dL. Statistical significance was not approached at any of the time lengths with MELD scores.

CONCLUSIONS

Child-Pugh score correlates better than MELD score to overall patient survival and is a better predictor than MELD score of survival at specific time points. Of the components of the Child-Pugh and MELD systems, albumin level is the most useful predictor of survival.

Endovascular recanalization of the thrombosed filter-bearing inferior vena cava

PURPOSE

To evaluate the authors' preliminary experience with use of endovascular methods to treat inferior vena cava (IVC) thrombosis in patients with IVC filters.

MATERIALS AND METHODS

Catheter-directed thrombolysis, balloon maceration, mechanical thrombectomy, and stent placement were used to treat 10 patients with thrombosis of filter-bearing IVCs causing symptoms in 18 limbs. Procedural challenges, technical and clinical success, complications, postprocedural filter status, and postprocedural pulmonary embolism (PE) prophylaxis were monitored.

RESULTS

Technical and clinical success were achieved in 15 of 18 (83%) and 14 of 18 symptomatic limbs (78%), respectively. Major bleeding (muscular hematoma) occurred in one patient (10%). Postprocedural PE prophylaxis included anticoagulation (n = 8) and placement of a new filter into a newly placed Wallstent (n = 1). During clinical follow-up, no clinically detectable PE was observed. Data pertaining to late limb status were available at a median of 19 months (range 1-46 months) follow-up in seven patients: three patients were asymptomatic, two patients had ambulatory edema only, one patient had constant mild edema, and one patient had constant severe edema. Postprocedural filter stability was radiographically documented at a median of 255 days (range, 4-1021 d) of follow-up.

CONCLUSION

Endovascular recanalization of the occluded IVC is feasible even in the presence of an IVC filter.

Doppler evaluation of transjugular intrahepatic portosystemic shunts

Transjugular intrahepatic portosystemic shunts are becoming an increasingly popular technique for the treatment of portal hypertension and its complications. However, to maintain patency, revisions are periodically required to treat stenosis and thrombosis. At many centers, Doppler sonography is used for routine follow-up. A variety of hemodynamic parameters, including main portal vein velocity, maximum stent velocity, minimum stent velocity, velocity gradient in the stent, temporal changes in stent velocity, flow direction in the intrahepatic portal and hepatic veins, and pulsatility of flow in the stent can be used. Many studies have confirmed that Doppler sonography is a valuable, noninvasive means of detecting stent malfunction, although the criteria vary somewhat at different institutions.

Safety and efficacy of transjugular intrahepatic portosystemic shunt creation for the treatment of hepatic hydrothorax

PURPOSE

To evaluate safety and efficacy of transjugular intrahepatic portosystemic shunt (TIPS) creation for hepatic hydrothorax (HHyd).

MATERIALS AND METHODS

Twenty-one patients underwent TIPS creation for HHyd. A prospective TIPS database and medical records were reviewed. Clinical and radiographic outcomes were recorded as complete (symptom/effusion resolution), partial (improved symptoms/effusion), or none. Data patterns were examined with chi(2) tests and Kaplan-Meier analysis.

RESULTS

Patients included 12 women and nine men, with a mean age of 56 years, all with Child class B (n = 7) or C (n = 14) disease. The technical success rate was 100%. Mean follow-up was 223 days. Twenty-nine percent (six of 21) died within 30 days of TIPS creation, 10% (two of 21) underwent transplantation within 30 days, and 62% (13 of 21) survived beyond 30 days. Data were incomplete in two patients. Clinical response was classified as complete in 63% (12 of 19), partial in 11% (two of 19), and none in 26% (five of 19). Radiographic response was classified as complete in 30% (six of 20), partial in 50% (10 of 20), and none in 20% (four of 20). Nonresponders had multisystem organ failure, and all but one died within 30 days. However, of the 13 patients surviving longer than 30 days, 10 (77%) had a complete clinical response.

CONCLUSION

TIPS is a relatively safe and effective method of controlling HHyd. The majority of patients experienced improvement or resolution of clinical symptoms with a variable reduction in the quantity of pleural fluid. There was a tendency among nonresponders to die within 30 days.

Transjugular intrahepatic portosystemic shunt placement in the setting of polycystic liver disease: questioning the contraindication

Although polycystic liver disease has long been listed as a contraindication to transjugular intrahepatic portosystemic shunt (TIPS) creation, two cases of TIPS placement in that particular clinical setting have been reported. Another case is reported in this article and the clinical course over 21 months of follow-up is examined. The discussion reviews the mechanics of TIPS creation in a polycystic liver and the vague premise of the polycystic liver as a contraindication to TIPS.

Angioscopic observations after percutaneous thrombectomy of thrombosed hemodialysis grafts

PURPOSE

To use angioscopy to evaluate and compare the amount of residual thrombus and endoluminal wall damage in hemodialysis grafts after percutaneous thrombectomy procedures.

MATERIALS AND METHODS

Thirty-nine thrombectomy and angioscopy procedures were performed in 35 patients. Percutaneous thrombectomy methods included eight different mechanical thrombectomy devices and the "lyse and wait" technique. Videotaped images of 33 angioscopic examinations were independently reviewed by three radiologists. Two parameters-the amount of residual thrombus and degree of endoluminal wall damage-were scored on a scale of 1 to 5. Data were initially analyzed to validate the grading system and then further studied to compare the different thrombectomy techniques.

RESULTS

The Spearman rank order analysis validated the data pertaining to the amount of residual thrombus (r = 0.71, P < .0001), but there was poor correlation between reviewers regarding the degree of endoluminal wall damage. Combined scores from three reviewers revealed that the Cragg brush and Percutaneous Thrombectomy Device (PTD) left the smallest amounts of residual thrombus. The other methods tested, listed by increasing amount of residual thrombus, were the Endovac, Hydrolyser, Amplatz Thrombectomy Device, AngioJet, Oasis, and the lyse and wait technique. There were two complications related to angioscopy procedures.

CONCLUSION

Subjective observations reveal that wall-contact thrombectomy devices leave less residual thrombus than hydrodynamic devices, aspiration devices, or the lyse and wait technique.

Hemodynamics revealed by Doppler sonography in patients who have undergone creation of transjugular intrahepatic portosystemic shunts: comparison of 10- and 12-mm metallic stents

OBJECTIVE

The purpose of this study was to determine whether differences exist in baseline flow velocities in the main portal vein and the stent after the creation of transjugular intrahepatic portosystemic shunts with 10- and 12-mm Wallstents.

SUBJECTS AND METHODS

We used Doppler sonography to determine baseline flow velocities in the stent and the main portal vein in 80 patients (38 patients with 10-mm Wallstents dilated to 10 mm and 42 patients with 12-mm Wallstents dilated to 12 mm) who had undergone creation of trans jugular intrahepatic portosystemic shunts without complications.

RESULTS

We found no significant difference in the maximum flow velocity in the stent between the patients with 10-mm stents (160.3+/-34.3 cm/sec) and those with 12-mm stents (164.4+/-33.8 cm/sec). We also found no significant difference in the minimum flow velocity in the stent between the 10-mm group (132.4+/-28.9 cm/sec) and the 12-mm group (126.7+/-28.3 cm/sec). However, flow velocity through the main portal vein was significantly higher in the patients with 12-mm stents (53.6+/-18.4 cm/sec) than in those with 10-mm stents (45.1+/-13.8 cm/sec) (p < .03).

CONCLUSION

After creation of transjugular intrahepatic portosystemic shunts, baseline flow velocities in the main portal vein in patients with 12-mm stents exceeded those in patients with 10-mm stents, although neither maximum nor minimum flow velocities in the stent differed between these two groups of patients. These findings suggest that criteria for shunt malfunction that use flow velocity in the main portal vein may need modification when 12-mm stents are being evaluated.

Encephalopathy after transjugular intrahepatic portosystemic shunting: analysis of incidence and potential risk factors

OBJECTIVE

Our purpose was to estimate the incidence of encephalopathy after transjugular intrahepatic portosystemic shunting (TIPS) related primarily to the diversion of portal vein blood flow and to identify periprocedural factors to predict patients at risk.

MATERIALS AND METHODS

All patients who underwent TIPS with at least 1 month of clinical observation after the procedure were monitored for clinically evident encephalopathy. Other variables that could individually induce encephalopathy were retrospectively analyzed for interrelationships with spontaneous or worsened encephalopathy.

RESULTS

Of the 150 patients, 68 (45%) suffered from encephalopathy after TIPS, but in only 33 (22%) was it new or worse than baseline measurements obtained before TIPS; in 18 of these 33 patients, an underlying medical cause was implicated. Fifteen (10%) of the 150 patients developed mental dysfunction, usually mild and well controlled, thought to be related only to TIPS and not to any underlying morbidity. Low portal vein pressures after TIPS were found to be interrelated with new or worsened spontaneous encephalopathy (p = .04). Like-wise, advanced age (> 59 years old) weakly corresponded to the development of encephalopathy after TIPS.

CONCLUSION

TIPS causes an acceptably low rate of encephalopathy that is usually mild. No specific variables exist for predicting the development or progression of encephalopathy after TIPS.

Doppler sonography findings associated with transjugular intrahepatic portosystemic shunt malfunction

OBJECTIVE

Our purpose was to determine the overall accuracy of Doppler sonography and the accuracy of specific Doppler parameters associated with a compromised transjugular intrahepatic portosystemic shunt (TIPS).

MATERIALS AND METHODS

For 43 patients who had undergone TIPS, 64 correlated sonogram-venogram paired examinations were analyzed. Sonographic parameters assessed included absolute velocities plus absolute and percentage changes in velocities measured in the main portal vein (MPV) and in several intrashunt locations (including peak and minimum velocity). Direction of flow and change in direction of flow in the left and right portal veins were also examined. TIPS malfunction was defined as any shunt with greater than or equal to 50% stenosis or any stenosis with a portosystemic gradient greater than 15 mm Hg.

RESULTS

The prospective interpretation of the sonograms using all available parameters resulted in a sensitivity of 92% and a specificity of 72% for detecting TIPS malfunction. Peak shunt velocity (absolute velocity and velocity change), distal shunt velocity, MPV velocity (absolute velocity and percentage change in velocity), change in minimum shunt velocity, and direction of flow in branch portal veins were found to have statistically significant differences between normal and abnormal shunts. Sensitivities for these individual parameters ranged from 64% to 84%, and specificities ranged from 70% to 100%. When either the MPV velocity or the distal shunt velocity was abnormal, the sensitivity was 94%. When both parameters were abnormal, the specificity for detecting TIPS malfunction was 100%.

CONCLUSION

Doppler sonography is a sensitive and relatively specific means of revealing TIPS malfunction. Accuracy depends on analysis of multiple sonographic parameters.