Cormac Farrelly

Medical emergencies and cardiopulmonary arrests in interventional radiology

PURPOSE To evaluate the circumstances and determine the outcomes of medical emergencies (MEs) and cardiopulmonary arrests (CPAs) in patients undergoing interventional radiology (IR) procedures. MATERIALS AND METHODS Retrospective review of all MEs and CPAs that occurred between July 2006 and December 2011 was performed. Procedure type, technical outcome, complications, etiology and location of ME/CPA, event outcome, and postevent mortality were collected. RESULTS A total of 58 events occurred during 38,927 procedures (0.15%). Complete records were available for 55 events (43 MEs, 12 CPAs) in 53 patients (mean age, 63 y; 58.5% male) during 37 inpatient (27 MEs, 10 CPAs) and 18 outpatient (16 MEs, two CPAs) encounters. Seven events (13%; six MEs, one CPA) occurred before the start of the procedure, and 18 (33%; 16 MEs, two CPAs) occurred in the periprocedural holding area. Thirty-five procedures (64%) were completed successfully. Forty-two patients (76%) were alive at discharge, 37 (67%) at 1 month, 26 (47%) at 3 months, and 23 (42%) at 1 year. Procedural complications were attributed as the main cause of 22 MEs (51%) and one CPA (8%; P = .018). The relative risk (RR) of an ME or CPA occurring during a hemodialysis access case versus all other cases was 5.2 (95% confidence interval = 3.02-8.95; P < .0001). CONCLUSIONS Although the incidence of MEs/CPAs in patients undergoing IR procedures is low, the 1-year mortality rate following these events is high. MEs are significantly more likely than CPAs to be directly attributed to a procedural complication. The RR of MEs/CPAs is significantly higher in hemodialysis access interventions.

Catheter-based Intraaccess Blood Flow Measurement as a Problem-solving Tool in Hemodialysis Access Intervention

PURPOSE To investigate retrospectively the use of catheter-based intraaccess blood flow measurements as an adjunct to physical examination and fistulography in hemodialysis access interventions. MATERIALS AND METHODS Among 1,540 dialysis interventions performed at a single institution in a 2.5-year period, 104 qualifying catheter-based flow measurements were made in 70 mature native fistula interventions in 55 patients and 34 graft interventions in 31 patients. The flow rate threshold prompting intervention was generally 600 mL/min, but some variation existed depending on the clinical setting. RESULTS The most common indication for measurement of blood flow was to determine the hemodynamic significance of a fistula inflow stenosis (n = 25), of which only four had subsequent intervention. Other common indications included decision-making resulting in further angioplasty or stent implantation of noninflow lesions (fistulas, n = 10; grafts, n = 23) versus termination of the procedure (n = 23), problem-solving in cases in which there was no visible lesion to explain the clinical indicator of access failure (n = 17), evaluation for high-flow-related cardiac risk in aneurysmal fistulas (n = 13), suboptimal evaluation of the inflow (n = 8), and suboptimal physical examination (n = 6). Overall, flow measurements supported a decision to perform angioplasty (n = 11) or stent placement (n = 3) in 17% of fistula interventions and 35% of graft interventions. CONCLUSIONS The major benefit of flow measurement was to support a decision to withhold further angioplasty or stent placement.

Translumbar Hemodialysis Catheters in Patients with Limited Central Venous Access: Does Patient Size Matter?

PURPOSE To describe a single institutional experience with translumbar tunneled dialysis catheters (TDC) and compare outcomes between patients with normal and abnormal body mass index (BMI). MATERIALS AND METHODS Translumbar TDCs placed between January 2002 and July 2011 were reviewed retrospectively. There were 33 patients; 18 had a normal BMI<25, and 15 had an abnormal BMI>25. Technical outcome, complications, indications for exchange or removal, and BMI were recorded. Catheter dwell time, catheter occlusion rate, frequency of malposition, and infection rates were collected. RESULTS There were 92 procedures (33 initial placements) with 7,825 catheter days. The technical success rate was 100%. Two minor (2.2%) and three major (3.3%) complications occurred. The complication rate did not differ significantly between patients with a normal BMI and patients with an abnormal BMI. Median catheter time in situ (interquartile range) for all patients was 61 (113) days, for patients with normal BMI was 66 (114) days, and for patients with abnormal BMI was 56 (105) days (P = .9). Primary device service intervals for all patients, patients with normal BMI, and patients with abnormal BMI were 47 (96) days, 63 (98) days, and 39 (55) days (P = .1). Secondary device service intervals for all patients, patients with normal BMI, and patients with abnormal BMI were 147 (386) days, 109 (124) days, and 409 (503) days (P = .23). Catheter-related central venous thrombosis rate was 0.01 per 100 catheter days (n = 1). CONCLUSIONS Translumbar TDC placement can provide effective hemodialysis in patients with limited venous reserve regardless of the patients BMI. An abnormal BMI (>25) does not significantly affect complication rate, median catheter time in situ, or primary or secondary device service interval of translumbar TDCs.

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.

What Are the Indications for Prophylactic Embolization of Renal Angiomyolipomas? A Review of the Current Evidence in the Literature

Renal angiomyolipomas (AMLs) are benign tumours that may occur sporadically in the general population or in patients with tuberous sclerosis complex. The concern with AMLs is that of retroperitoneal hemorrhage, which can be fatal. Classically the trigger for prophylactic intervention was thought to be an AML diameter of ≥4 cm. However, this value is largely based on data from case series and heterogeneous retrospective studies. The PICO (patient, intervention, comparison, outcome) paradigm was used to systematically search the Cochrane database, TRIP database, and PubMed. The quality of evidence in the literature is poor regarding the indications for prophylactic embolization of AMLs (level 4). There are no prospective studies that adequately assess embolization vs other treatment modalities. However, using the available evidence we have produced recommendations for when intervention should be considered. We have also made recommendations regarding the direction of future research.

Author’s Response to: Letter to Editor

To the editor, Thank you to Conroy et al. for their interesting letter. This certainly provides further evidence supporting the safety and efficacy of pneumatic compression devices (PCD) for achieving haemostasis in patients undergoing haemodialysis fistula intervention. Their series included 116 device deployments in an unstated mixture of arteriovenous fistulas and grafts, and so, it would also appear to support its use after accessing dialysis grafts and with sheath sizes up to 7 Fr. It is interesting that both case series examining this use of achieving haemostasis used the same PCD, namely the Safeguard Radial Compression Device (Merit Medical Systems Inc. Utah, USA). This is a 26-cm-long self-adhesive band that is designed for achieving patent haemostasis after radial artery catheterisation. We believe it is important to point out that not all radial artery PCDs are the same. For example, other PCDs incorporate nonadhesive wrist bands that are required to fit completely around the wrist (similar to a watch) and may have a larger surface area. Where a wrist band may be expected to work at a radiocephalic Cimino-Brescia-type fistula, if the band is not large enough to fit around the elbow it will not be possible to use it on a brachiocephalic or brachiobasilictype fistula or indeed many arteriovenous grafts. Also PCDs with a larger surface area may make it more difficult to achieve haemostasis at two adjacent fistula/graft catheterisation access sites. One of the advantages of using a PCD is the ability to accurately control the amount of compression at the access site. This allows optimal compression without occlusion. The concept of patent haemostasis is now well established with transradial artery access, and indeed, there is evidence that a decrease in radial artery occlusion after radial artery catheterisation can result from prophylactic ipsilateral ulnar artery compression [1]. Although a dialysis fistula has a significantly larger lumen than the radial artery, it would be interesting to study whether similar benefits in radiocephalic fistula patency rate could be achieved with concomitant ulnar artery compression. Regardless, further studies are warranted looking at the use of various types of PCDs for haemostasis and ideally manufacturers would design PCDs specifically for use after dialysis access intervention. In the interim, we continue to use the PCD described in our study and we would advise our colleagues to join us with a technique that is simple, speedy, safe and sutureless.