Weekly prophylactic urokinase instillation in tunneled central venous access devices

PURPOSE: To determine the safety and efficacy of weekly prophylactic urokinase therapy in tunneled central venous access devices (VADs). MATERIALS AND METHODS: A prospective, randomized study was performed in 105 patients who underwent tunneled VAD placement between March 1997 and April 1998. The patients were randomized to receive either twice-daily heparin flushes (14 heparin flushes per week; group A, n = 52) or twice-daily heparin flushes with once-weekly urokinase (UK) instillation (13 heparin flushes, one UK flush per week; group B, n = 53). Patients were followed up by examination and/or interview at 1, 3, and 6 months for signs and symptoms of delayed catheter-related complications. RESULTS: The total number of indwelling catheter-days was similar between groups (5,450 in group A, 5,276 in group B). The total number of infectious complications and fibrin sheaths formed was greater for group A (n = 11; 21.1%) than group B (n = 3; 5.7%) (P = .02). There were no side effects noted from the prophylactic UK administrations. CONCLUSION: Prophylactic UK is advantageous in preventing delayed catheter-related complications.     

Central venous access devices

Over the years, central lines have evolved from short-term, triple-lumen catheters used to administer medications and fluids to acutely ill patients into central venous access devices (CVADs) designed for long-term use in both hospitalized patients and outpatients. However, complications related to CVADs, especially catheter-related infections, can be costly in terms of patient mortality and health care dollars. Radiologic technologists who have a working knowledge of CVADs can contribute to patient management, reduce complications and provide safe, comfortable care.     

Infectious complications of venous access devices

Infection represents one of the most common venous access device (VAD)-related complications requiring catheter removal. Recognition of such complications is essential to provide appropriate therapy in the setting of active infection. This article reviews the definition of various types of infections, as well as reviewing the diagnosis, prevention, and treatment of VAD-related infections.     

Principles of non-tunneled central venous access

Non-tunneled central venous access has become an important tool in the management of the sick patient, particularly in the intensive care unit. Image guidance allows more precise placement of lines with overall lower complication rates compared with guidance by physical landmarks. The use of image guidance has brought a procedure traditionally performed by surgeons into the realm of the interventional radiologist. Techniques for placement of non-tunneled central venous catheters, hemodialysis catheters, and peripherally inserted central catheter lines will be discussed.     

Cavoatrial junction and central venous anatomy: implications for central venous access tip position

PURPOSE: To quantify the anatomic relationships of the cavoatrial junction and propose a system for describing central venous access device tip location on the basis of structures visible on chest radiographs. MATERIALS AND METHODS: The authors performed a retrospective study of 100 consecutive computed tomographic (CT) studies from a predominantly pediatric population consisting of 52 male and 48 female patients aged 12-28 years (mean age, 16 years). With use of multiplanar and scout images, relevant mediastinal structures were marked, vertebral levels were noted, and measurements were made electronically. Catheter tip positions were recorded in the 26 children who had central catheters. RESULTS: A vertebral body unit was defined as the distance between the inferior endplate of one vertebra to the inferior endplate of the next, with the upper intervertebral disk included. The most reliable estimate of cavoatrial junction position is a point two vertebral body units below the carina; there was no association with patient age or other parameters. CONCLUSIONS: A more accurate understanding of the superior vena cava anatomy is essential for the correct interpretation of central venous access device position. The true cavoatrial junction is located more inferiorly than commonly believed and is not accurately estimated with commonly used imaging landmarks. A point two vertebral body units below the carina enables the reliable estimate of the position of the cavoatrial junction. Catheter tip position can be most reliably described in vertebral body units below the carina, with use of the thoracic spine as an internal ruler.     

Peripherally inserted central catheter placement in patients with unsuspected central venous obstruction

PURPOSE: To evaluate the feasibility and clinical usefulness of peripherally inserted central catheter (PICC) placement in patients with unsuspected central venous obstruction. MATERIALS AND METHODS: Of 3,272 PICC procedures performed from January 1999 to July 2006, 57 patients had central venous stenosis or obstruction during placement of the PICC. Sixty PICC placements were performed in 57 patients (30 male and 27 female patients; mean age, 59 years). The PICC placements in 57 patients were evaluated with regard to the location and severity of venous disease, underlying causes of venous stenosis or obstruction, catheter placement technique, technical success rate, catheter dwelling time, and complication rate. RESULTS: There were 48 complete obstructions and 12 stenoses. Ipsilateral lesion passage was attempted in 31 patients and was successful in 26 (84%) and unsuccessful in five (16%). Over-the-wire PICC placement was performed in 16 patients, and PICC placement after angioplasty was performed in 10. Contralateral PICC placement without a trial of traversing the lesion was done in 26 patients. The PICC dwell time ranged from 2 to 150 days (median, 25.5 days). Complications occurred in four of the 57 patients (7%) and included tube tip migration (n = 1), catheter occlusion (n = 1), and catheter infection (n = 2). CONCLUSIONS: PICCs can be safely placed across central venous lesions in patients with asymptomatic central venous stenosis or obstruction. Contralateral placement is favorable in cases of ipsilateral passage failure.     

中心静脉通道的建立及其在临床中的应用

目的 倡导建立中心静脉通道的重要性,比较经右锁骨下静脉（TSCV）和右颈内静脉（TIJV）两种途径建立中心静脉通道的技术特点。方法 自1999年3月至2001年6月间共完成中心静脉通道植入术348例次,其中经右锁骨下静脉270例次,经右侧颈内静脉78例次;导管留置时间13－75d,平均23d。结果 TSCV组270次,268次成功,成功率99％。操作中和留置期间11例出现严重并发症,包括气胸2例,误留入锁骨下动脉1例,留置管阻塞3例,留置管进入右颈内静脉引起输液异常3例。穿刺口感染2例。TIJV组78次75次成功,成功率96％,严重并发症1次。结论 中心静脉通道在临床上具有很大的实用价值,其成功率与操作者解剖知识及技术熟练程度有关。     

Noninfectious complications of long-term central venous catheters: radiologic evaluation and management

During a 5-year period, 416 long-term double-lumen central venous catheters were inserted into 288 patients. In these patients, 106 catheter venograms and nine upper extremity venograms were performed. All studies were reviewed retrospectively to determine the nature and prevalence of noninfectious catheter-related complications, to evaluate the efficacy and safety of streptokinase therapy, and to determine if catheter venography should be performed before streptokinase therapy is started. Noninfectious complications occurred in 66 (23%) patients. Complications that resulted in catheter malfunction included deposition of fibrin around the catheter tip (formation of a fibrin sheath) in 44 (57%) instances, a constricting suture in six, abutment of the catheter tip against the venous wall in eight, catheter leak in two, and migration of the catheter completely out of the vein in three. Venous thrombosis developed in 11 patients. Treatment with low doses of streptokinase successfully relieved catheter obstruction due to a fibrin sheath in 27 (87%) of 31 instances. No bleeding complications occurred. Five patients had malpositioned catheters in the azygous, axillary, or internal jugular veins. By use of a deflector wire or snare inserted via the femoral vein, all five were relocated successfully into the superior vena cava. Recognition of noninfectious complications associated with use of long-term catheters is important for institution of appropriate therapy, which in many instances obviates removal of the catheter. Formation of a fibrin sheath in only 57% of cases of catheter malfunction provides an argument for performing catheter venography before streptokinase therapy is started. Low-dose streptokinase therapy for long-term central venous catheters occluded by a fibrin sheath is safe and efficacious.     

A concise history of central venous access

Central venous access has become a mainstay of modern interventional radiology practice. Its history has paralleled and enabled many current medical therapies. This short overview provides an interesting historical perspective of these increasingly common interventional procedures.     

Pinch-off syndrome: a complication of implantable subclavian venous access devices

Implantable central venous access devices placed via the subclavian vein may become obstructed by thrombosis, impingement against a vein wall, or compression between the clavicle and first rib. The latter has been termed pinch-off syndrome (POS). Eleven patients with POS were studied, including one whose catheter had fractured and one whose catheter had fragmented. They were compared with 22 matched control patients and 100 consecutive routine clinic patients. Each catheter was graded: 0 = normal, 1 = abrupt change in course with no luminal narrowing, 2 = luminal narrowing, and 3 = complete catheter fracture. POS was present in most (eight of 11) cases within 3 weeks after placement. A grade 1 catheter was common (33%) among control subjects, but grades 2 and 3 were uncommon (1%). Catheter fracture or fragmentation was seen in two of five cases with long-term (greater than 3 weeks) pinching (grade 2 catheter). The following conclusions were reached: Grade 2 represents significant catheter compression and the potential for serious complications. Grade 1 is of uncertain clinical significance, due to its high prevalence in control subjects.     

Life-threatening vascular complications after central venous catheter placement

The purpose of this retrospective study was to report 11 cases of severe vascular complications after central venous catheter misplacement. For each patient, data collection included body mass index, the diagnosis at admission, the site of the procedure, the type of catheter, coagulation parameters, the imaging modalities performed and the applied treatment. Eight patients had a lesion of the subclavian artery. Brachiocephalic vein perforations were assessed in three more patients. All patients had a chest roentgenogram after the procedure, six a CT examination, and four an angiographic procedure. Seven patients had a body mass index above 30, and 5 patients had coagulation disorders prior to the procedure. Seven patients were conservatively managed, 2 patients died despite resuscitation, 1 patient was treated with a stent graft, and one by superselective embolization. Subclavian or jugular vein temporary catheter positioning is a practical approach. Identification of any iatrogenic perforation of the subclavian artery or central veins urges obtaining a chest roentgenogram and, when required, a chest CT, selective angiograms or venograms. Body mass index superior to 30, previous unsuccessful catheterization attempts, and coagulation factor depletion seemed to account for risk factors. Recognition of clinical and radiological complications is mandatory.     

Evaluation and management of central venous access complications

Venous access is 1 of the most common interventional procedures in the USA. Using image guidance in the last 2 decades, obtaining venous access has become increasingly routine, and the complications commonly associated with the procedure have significantly decreased. However, interventional radiologists still encounter both early and late complications routinely associated with both central and peripherally inserted access devices. This article discusses the most common and some unusual complications seen with the placement of these devices. We also briefly discuss the management of these complications.