Adrenal venous sampling in primary aldosteronism: lessons from over 600 single-operator procedures.

Adrenal vein sampling (AVS) is a recommended if not required final diagnostic step in the investigation of primary aldosteronism, the most common cause of remediable secondary hypertension. Successful adrenal vein sampling is operator-dependent. Having performed over 600 such procedures at our centre over 20 years, our single-operator experience is described in detail for the purpose of training future radiologists as well as for use by those who are planning to start an AVS programme of their own. This updated review considers new developments in primary aldosteronism disease understanding that are relevant for AVS performance and protocols, along with technical enhancements that may be used for special cases. Detailed understanding of variant anatomy and tips for successful cannulation are keys to success, along with an endocrinology and clinical chemistry partnership for continuous quality control. A successful AVS programme offers patients a hope for cure of resistant hypertension.

Analysis of early failure of tunneled hemodialysis catheters.

OBJECTIVE: Tunneled hemodialysis catheters are often placed by the interventional radiology service using sonographic guidance and fluoroscopy for safe and optimal placement. The aim of this study was to determine the causes of early failure (

Image-guided central venous catheter placement for apheresis in allogeneic stem cell donors.

Peripheral blood stem cell harvest by apheresis is an increasingly important procedure utilized in the treatment of many malignancies. Whether autologous or allogeneic, it is frequently performed via peripheral access because of concern over major complications associated with central venous catheter placement. This study was to determine the safety and success, complications and premature failure rates for radiolocally placed ultrasound-guided non-tunneled central venous catheters placed for apheresis in a donor (allogeneic) population. One hundred central venous catheters were placed in ninety-one individuals for allogeneic stem cell harvest. Procedural success and complications relating to placement were noted in all. In 97 cases the number of needle passes required for venous cannulation and whether this was achieved with a single wall puncture was noted. Duration of catheterization and reason for removal were recorded in all cases. All catheters were placed by a right transjugular route. Venous cannulation and functioning line placement was achieved in every case; 92/97 (95%) required only a single needle pass and 84/97 (87%) only a single wall puncture. There were no placement related complications; 94 catheters were removed the same day with the remainder removed within 48 hr. All completed apheresis. Our study demonstrates the safe use of central venous catheters for apheresis in normal donors if ultrasound guidance is used for the puncture and the duration of catheterization is short.

Value of frontal caval measurement in the placement of inferior vena cava filters.

OBJECTIVE: Inferior vena cavae (IVC) can be of unusual geometry, often having odd shapes and being oriented (in long axes) away from the horizontal plane. However, after insertion of a filter, most IVC adopt a circular cross-section. The objective of this study was to determine if the IVC diameter estimated by frontal measurement (cavogram equivalent) reflects the true circular diameter of the infrarenal vena cava. Diameter estimation is clinically important in the correct selection of a filter, because mega cavae (diameter 28 mm or greater) require a particular filter. METHODS: The infrarenal IVC was measured on computed tomographic (CT) scans in 136 patients. The frontal diameter was recorded as that which would be obtained by a cavogram. Corrected circular diameter was obtained by mapping the circumference of each cross-section on CT to a straight line and calculating diameter from circumference. RESULTS: The average frontal caval diameter was 20.5 (standard deviation 3.7) mm, whereas the average corrected circular diameter was 23.0 (standard deviation 3.4) mm. By frontal measurements, 6 IVC diameters were 28.0 mm or greater. Similarly, by corrected circular diameter, 6 IVC diameters were 28.0 mm or greater. However, of the 6 mega cavae extrapolated to cavograms, only 3 corresponded to mega cavae when corrected for true circular diameter. Yet, of the 6 mega cavae identified by corrected circular diameter measurement, 3 were not identified by frontal diameter assessment. Of the 6 patients with true mega cavae, 2 were being evaluated for right lower quadrant pain, 2 for lymphoma, 1 for a pelvic mass, and 1 for staging of a head and neck cancer. CONCLUSIONS: Cavograms can over- or underestimate the true diameter of an IVC, and may thus lead to incorrect filter choice. It is recommended that a sonogram or CT scan be obtained to visualize the IVC in cases of suspected mega cava, and that true circular diameters be used for selection and placement of IVC filters.

Should anticoagulant therapy be stopped or reversed before venous intervention?

PURPOSE: To determine the safety of venous intervention and the incidence of complications in patients undergoing venous interventional radiological procedures while receiving anticoagulant therapy. METHOD: Data were collected prospectively for a 1-year period. One hundred patients receiving anticoagulant therapy underwent interventional radiological procedures requiring venous cannulation. Of these, 87 had documented prolonged bleeding times. There were 50 inferior vena cavograms obtained and filters placed (29 transfemoral, 21 transjugular), and 50 transfemoral pulmonary angiogram obtained, all in patients with thrombo-embolic disease who were receiving anticoagulant therapy. In most cases venous access was achieved with real-time sonographic guidance. RESULTS: Venous access was gained in all patients in all groups. There were 41/50 filter placements and 46/50 pulmonary angiograms performed in the patients with prolonged clotting times in or above the therapeutic range. There were no cases of arterial puncture and no cases of venous bleeding either during or after the procedures. No other complications were recorded. CONCLUSION: Venous intervention in patients receiving therapeutic anticoagulation is safe, with no complications reported in our series. There is no need to discontinue anticoagulant therapy in patients with life-threatening thrombo-embolic disease. Real-time sonographic guidance greatly facilitates venous cannulation and avoids inadvertent arterial puncture.

A simplified method of gastropexy for transgastric enterostomy.

Radiological placement of gastrostomy tubes was first described in 1983. Percutaneous gastropexy to facilitate gastrostomy placement was reported in 1986. Debate has continued to this day regarding the necessity of gastric fixation. We describe our technique of a simplified gastropexy to facilitate transgastric enterostomy and advocate its more widespread use.

Radiologic placement of tunneled central catheters: rates of success and of immediate complications in a large series.

OBJECTIVE: The objective was to examine the success and immediate complication rates in a large series of radiologically placed tunneled central venous catheters. SUBJECTS AND METHODS: We prospectively recorded the success and immediate complication rates in 880 consecutive radiologically placed tunneled central venous catheters. We also recorded the indication for placement, the success of placement, the number of passes required, and whether a double- or single-wall puncture occurred. RESULTS: Hemodialysis was the most common indication for long-term venous access. Venous access was successful in all patients, and catheter placement was successful in 99.4% of patients, with only five failed placements. All patients in whom placement was initially unsuccessful underwent successful placement the same day. All catheters were placed using real-time sonographic guidance. Most were placed in an internal jugular vein, with 87.4% requiring only a single needle pass. The immediate complication rate was only 4.0%, and no major complications occurred. CONCLUSION: To our knowledge, this series is the largest for which the immediate complication and success rates for radiologically placed central venous catheters have been reported. Our results suggest that radiologic placement of tunneled central venous catheters is a safe and effective alternative to surgery.

Apheresis: another indication for radiologically placed central venous catheters.

OBJECTIVE: Apheresis is an important technique, used increasingly for a variety of conditions. It is sometimes performed via peripheral access because of concern over major complications associated with central venous catheter (CVC) placement. This study was to determine the safety and success of radiologic placement of CVCs for apheresis. METHODS: Data were collected prospectively for 278 CVCs placed under real-time sonographic or fluoroscopic guidance in the radiology department. Complications were noted in all cases; the number of passes required for venipuncture and whether this was achieved with a single wall puncture were noted in 265 cases; duration of catheterization and reason for removal of the catheter were recorded in all cases. The study group included 83 donors providing peripheral blood stem cells for allogeneic transplant. RESULTS: CVCs were successfully placed in all patients, 269 in the internal jugular and 9 in the femoral vein. In 87% of cases, only a single pass was required, and in 80% of cases venipuncture was achieved with a single anterior wall puncture. There was inadvertent but clinically insignificant arterial puncture in 6 cases (2%). In no case did this prevent CVC placement. Most catheters (211/274, 77%) were removed the same day. Only 3 catheters were removed prematurely (1%), 1 because of infection and 2 because of clotting. There was 1 case of venous bleeding. CONCLUSION: CVCs are safe for apheresis if real-time sonographic guidance is used for the puncture, guide wire and catheter placement are confirmed fluoroscopically, and the duration of catheterization is short.

Image-guided central venous catheters for apheresis.

Apheresis is an increasingly important procedure in the treatment of a variety of conditions, sometimes performed via peripheral access because of concern over major complications associated with central venous catheter (CVC) placement. This study sought to determine the safety and success for ultrasound and fluoroscopically guided, non-tunneled dual lumen CVCs placed for apheresis. Prospective data collection was made of 200 attempted CVC placements in the radiology department utilizing real time sonographic guidance. The complications relating to placement were noted in all and the number of passes required for venepuncture and whether a single wall puncture was achieved was recorded in 185 cases. Duration of catheterization and reason for line removal were recorded in all. Our study group included 71 donors providing peripheral blood stem cells for allogeneic transplant. CVCs were successfully placed in all patients, 191 lines in the internal jugular and seven in the femoral vein. 86.5% required only a single pass and 80.5% with only anterior wall puncture. Inadvertent but clinically insignificant arterial puncture occurred in six (3%) cases. In no case did this prevent line placement. There were no other procedure-related complications. 173 (87.4%) catheters were removed the same day. No catheters were removed prematurely. There was one case of prolonged venous bleeding. Our study demonstrates the safety of central venous catheters for apheresis provided that duration of catheterization is short and real-time sonographic guidance is used for the puncture, and guide wire and catheter placement are confirmed fluoroscopically.

Ultrasound monitoring in cannulation of the internal jugular vein: anatomic and technical considerations.

OBJECTIVE: To examine the effect of variations in anatomic features and operator experience on the success and complication rates of sonographically monitored cannulation of the internal jugular vein. PATIENTS AND METHODS: The authors prospectively collected data for ultrasound-monitored cannulation of the internal jugular vein in 150 patients. In all cases the radiologist recorded the side of puncture, the number of passes needed, the number of vein punctures (one or two), whether the walls were opposed during puncture and any complications. For the last 80 patients the following information was also recorded: the distance from the skin to the internal jugular vein, the diameter of the vein with the Valsalva manoeuvre and the location of the vein relative to the carotid artery. All but three of the cannulations were performed by one of three radiologists, all of whom had at least 5 years of experience. RESULTS: Cannulation was successful in all of the patients, and the first pass was successful in 133 (88.7%). These results are better than those of blind placement techniques reported in the literature. The only complications were hematoma and carotid puncture, which both occurred in the same two patients (1.3%). There was no significant difference among the radiologists in the number of passes needed (one-way analysis of variance, p > 0.05). The number of passes was independent of anatomic factors, including depth from skin, vein diameter or relative location. However, significantly more passes were needed for left-side punctures than for right-side punctures (Student t-test, p < 0.05). CONCLUSIONS: Real-time ultrasound monitoring is superior to blind techniques in cannulation of the internal jugular vein because of its ease, accuracy and safety. Sonographic real-time monitoring minimizes the impact of anatomic factors on success and complication rates. It is a safe and efficacious approach that should be preferred in the placement of central lines.

Outpatient percutaneous nephrostomy.

PURPOSE: To assess the feasibility of performing percutaneous nephrostomy (PCN) on an outpatient basis in a select group of patients. MATERIALS AND METHODS: In 6 years, 60 PCN procedures were performed in a subgroup of 48 patients (22 men, 26 women) carefully selected from a larger group of 881 nephrostomy procedures in 589 patients. Exclusion criteria included hypertension; untreated urinary tract infection, coagulopathy, and staghorn calculi. Indications were calculus (n = 17), benign stricture (n = 10), and malignant ureteric obstruction (n = 21). RESULTS: There was 100% technical success. Six of 48 patients (12%) were admitted within a week of PCN; there were no cost savings in these patients. Three of these patients (6%) were admitted as a direct consequence of PCN; one had sepsis, one had bleeding, and one was unable to manage the PCN tube. Outpatient treatment saved the cost of hospitalization in 42 patients (88%). CONCLUSION: Outpatient PCN is feasible and safe in carefully selected patients and yields major cost savings because it precludes hospital admission.

Radiology reports: how much descriptive detail is enough?

OBJECTIVE: The purpose of our study was to determine whether physicians prefer radiology reports with no description, a brief description, or a detailed description of the radiologic findings. We also examined the effects of various clinical circumstances and physician characteristics (e.g., specialty and number of years in practice) on these preferences. This study, which is limited to commonly encountered scenarios, is concerned solely with the description of imaging findings and not with other aspects of the reports, such as the diagnosis and technique. MATERIALS AND METHODS: A questionnaire was sent to the 100 physicians who most frequently refer patients to our practice for chest radiographs and abdominal sonograms. The questionnaire outlined six clinical scenarios. For each scenario the physician was asked to indicate the preferred radiology report from a set of three reports varying in descriptive detail. RESULTS: Seventy-seven physicians replied. For a normal chest radiograph in a patient without specific chest symptoms, the most popular report format indicated simply that the examination was normal. When there were clinical findings involving the chest or abnormal radiologic findings, the majority of referring physicians desired a description of the findings and the radiologic diagnosis. For abdominal sonograms the majority of physicians favored reports detailing the findings, even when the findings were normal. In all instances the preferences expressed were independent of the academic status, number of years in practice, number of reports read per day, and specialty of the referring physician. CONCLUSION: Our results show that preferences of referring physicians for the extent of description of imaging findings included in radiology reports depend on the clinical circumstances. In the specific clinical scenarios examined, physicians preferred that the report include a brief description of the findings, except for screening chest radiographs, for which "normal examination" was an acceptable report. The referring physicians' preferences regarding the amount of descriptive detail included in the report were independent of their specialty, academic status, and experience.

Sonographic assessment of infrarenal inferior vena caval dimensions.

The dimensions of the infrarenal inferior vena cava during quiet respiration, single leg lifting, and breath-holding were assessed using sonography in 156 patients. Sonographic assessment of infrarenal inferior vena caval dimensions was feasible in 69% of patients. Measurements during breath-holding were significantly greater than during quiet respiration (P < 0.001) and leg lifting (P < 0.005), although in approximately one quarter of the patients the mean calculated diameter was greatest during quiet respiration. we conclude that sonographic assessment of infrarenal inferior vena caval dimensions is feasible, but it should be performed during quiet respiration and breath-holding to allow for variation with different respiratory maneuvers.

Severity of disease score as a predictor of mortality after caval filter insertion.

PURPOSE: To estimate 30-day mortality after vena caval filter insertion and assess the usefulness of a severity of disease score in predicting postprocedure 30-day survival. PATIENTS AND METHODS: Records of 40 consecutive patients undergoing inferior vena caval filter insertion over a 2 1/2-year period were retrospectively reviewed. A severity of illness score for each patient was calculated based on the weighting system described for the APACHE (Acute Physiology and Chronic Health Evaluation) II system. In addition, 30-day postprocedure survival was determined. RESULTS: Seven patients died within 30 days of the procedure (18%). The use of a severity of disease score of greater than 15 as a predictor of postprocedure 30-day mortality had a sensitivity of 50%, specificity of 97%, positive predictive value of 75%, a negative predictive value of 91.4%, and accuracy of 90%. CONCLUSIONS: The 30-day mortality after caval filter insertion is significant. A severity of disease score is a useful predictor of patients likely to survive following caval filter insertion. On this basis it may be possible to establish criteria for more beneficial use of vena caval filters.