Flow characteristics of peripherally inserted central catheters.

PURPOSE: Clinical applications of peripherally inserted central catheters (PICCs) are limited by the relatively small lumina and long lengths of these devices. Quantitative analysis of the flow capabilities of a variety of PICCs was performed to aid in deciding which patients should have a PICC and in selecting the appropriate catheter. MATERIALS AND METHODS: Sixteen different PICCs from six manufacturers were infused at flow rates of 25-270 mL/h. Infusions were performed with distilled water, normal saline, total parenteral nutrition solution, intralipids, and blood. Flow versus pressure curves were generated for each PICC and infusate. Additional catheter data recorded included the working length, outer diameter (OD), and inner diameter (ID) of the PICCs. RESULTS: Because of the thin wall construction of polyurethane catheters, PICCs made from polyurethane showed much better flow rates than silicone PICCs of a comparable OD. The measured ODs of the PICCs were 4-6 F, whereas the IDs ranged from 0.012 to 0.032 inch. Because of the small ID of some PICCs, infusing blood or intralipids is not practical. CONCLUSION: There is significant variability in the flow capabilities of available PICCs. Many of the PICCs require pressures greater than those that can be generated by commercially available infusion pumps. Matching PICC characteristics to the desired application will avoid many of the clinical problems currently encountered with PICCs.

Percutaneous transluminal angioplasty of visceral arterial stenoses: results and long-term clinical follow-up.

PURPOSE: To determine the efficacy and safety of percutaneous transluminal angioplasty (PTA) of the visceral arteries. PATIENTS AND METHODS: We retrospectively evaluated the results of PTA performed in 20 visceral arteries in 19 patients (10 men, nine women; mean age, 63 years). Eleven patients had symptoms characteristic of mesenteric ischemia, four had atypical abdominal pain, and four were undergoing prophylactic dilation before undergoing another procedure involving the abdominal aorta. Clinical follow-up was possible in all patients. RESULTS: PTA was technically successful in 15 of 19 patients (79%); among these 15 patients, 12 (80%) did well clinically. Of the seven PTA procedures that were immediate failures, five failed secondary to an occult malignancy or to extrinsic arterial compression by the median arcuate ligament. Ten (83%) of the 12 patients in whom the procedures were immediate clinical successes are still clinically improved at 4-73 months follow-up (mean, 25 months). PTA was successful in only one of the four patients who had symptoms atypical of mesenteric ischemia, but it was successful in 11 of the 15 patients who had symptoms of mesenteric ischemia or who underwent prophylactic dilation. Major complications occurred in three (16%) of the 19 patients. CONCLUSION: PTA of visceral artery stenoses is effective in patients with symptoms of mesenteric ischemia. It is also effective as prophylaxis in patients undergoing additional procedures in the abdominal aorta.

Contemporary diagnostic approaches to acute pulmonary emboli.

Because of its availability and familiarity, the V/Q scan remains the most frequently used noninvasive screening study for the diagnosis of acute PE. Fast CT and MR imaging techniques probably will have more significant roles in the future in the diagnosis and management of PE, but limited availability and familiarity with these imaging modalities make it impractical to currently recommend them as primary screening tools for acute PE. Although the cost and time benefits appear to place fast CT ahead of MR imaging, more clinical experience and a greater understanding of the imaging nuances and pitfalls of interpretation for both fast CT and MR imaging are needed. Medicare reimbursements (both technical and professional fees) for a CT or MR scan are already competitive with a V/Q scan (Table 2), so that they may ultimately prove to be more cost-effective screening modalities for PE than a V/Q scan. Until the role for intraarterial DSA becomes further defined with clinical trials and outcome analyses, it cannot be recommended as a reference standard for the diagnosis of PE. Although conventional pulmonary angiography is associated with a 1% to 2% major nonfatal complication rate and a 0.1% to 0.5% mortality rate, chronic anticoagulation has reported major bleeding complication rates of 1.5% to 20% at 1 year, and inferior vena cava filters are associated with inferior vena cava thrombosis rates of 3% to 25%. Therefore, initiating or withholding therapy for the "presumed" presence or absence of PE based on a V/Q scan alone has the potential for generating excessive costs and morbidity in a large population of patients. Until the validity of fast CT and MR imaging have been proven, a pulmonary angiogram is required when there is any doubt about the diagnosis of PE. A negative pulmonary angiogram is often more useful in the management of a patient than an angiogram that demonstrates PE. By ruling out the presence of PE, an alternative and possibly more significant diagnosis will be pursued. Lastly, it is necessary for us to define more clearly the term clinically significant PE. This is important because fast CT, MR imaging and intraarterial DSA techniques can now reliably visualize third order pulmonary artery branches. Whether this degree of resolution allows for adequate detection of clinically significant PE will only be determined by extensive patient tracking and outcome analyses.

Recent development of rigors during infusion of urokinase: is it related to an endotoxin?

PURPOSE: This study was undertaken to determine the prevalence of rigors associated with the use of urokinase (UK) and to assay for the presence of an endotoxin in the UK solution. PATIENTS AND METHODS: Records of 75 patients who underwent 86 UK infusions between January 1988 and July 1992 were reviewed to evaluate for the development of UK-associated rigors. A modified chromogenic limulus amebocyte lysate (LAL) test was performed to determine the presence of endotoxin in four samples of UK from lots associated with rigors, one sample of UK not associated with rigors, sterile water, nonionic contrast medium, and ionic contrast medium. RESULTS: Between January 1, 1988, and July 10, 1990, 43 patients underwent 46 UK treatments (group 1) with no documented rigors (0% prevalence). In 45 of these 46 treatments, a standard, non-pulse-spray bolus of 75,000-500,000 IU of UK (mean dose, 182,222 IU) was used. Between July 11, 1990, and July 6, 1992, 38 patients underwent 40 UK treatments (group 2). In 33 of these 40 treatments, a standard bolus was given. Five patients received a pulse-spray bolus. The mean bolus was 213,768 IU (range, 100,000-500,000 IU). Eleven group 2 patients developed rigors (28% prevalence; P = .0005 vs group 1). The chromogenic LAL tests demonstrated no endotoxin in sterile water, nonionic contrast media, or ionic contrast media. Endotoxin was detected in small concentrations in the four samples of UK associated with rigors and in the UK sample not associated with rigors. CONCLUSION: The increase in the prevalence of rigors associated with the use of UK does not appear to be related to an endotoxin in UK, since the concentration of endotoxin detected is well below the threshold pyrogenic dose in humans.

Reducing the discomfort of lidocaine administration through pH buffering.

PURPOSE: A prospective, double-blind study was undertaken to evaluate the effect of using a buffered lidocaine solution on the perception of pain experienced by a patient during its intradermal injection. PATIENTS AND METHODS: One hundred fifty patients undergoing diagnostic angiographic and interventional procedures at the authors' institution were randomly assigned to receive a 1-mL aliquot of one of three lidocaine solutions: plain 1% lidocaine, 1% lidocaine diluted with normal saline in a 10:1 ratio, and 1% lidocaine diluted with 8.4% sodium bicarbonate in a 10:1 ratio. The lidocaine solutions were administered intradermally over 10-15 seconds. A numerical value was placed on the patient's perception of pain, separate from that associated with the 25-gauge needle insertion, with use of a linear visual analog scale. RESULTS: Mean pain scores were as follows: for the 1% lidocaine solution, 2.83 +/- 2.60; for 1% lidocaine plus normal saline solution, 2.89 +/- 2.34; and for 1% lidocaine plus sodium bicarbonate solution, 1.37 +/- 1.73 (P = .0018). CONCLUSION: Buffering lidocaine significantly decreased the discomfort associated with its administration as a local anesthetic.

Peripheral angioplasty balloon technology.

Changes in balloon and catheter technology have led to the development of smaller, more flexible, and less traumatic balloon dilatation systems. The physical principles that govern balloon angioplasty and the current status of balloon materials and catheter designs will be reviewed. A compilation of various angioplasty catheters is also summarized.

Balloon angioplasty above the aortic arch: immediate and long-term results.

OBJECTIVE: Angioplasty above the level of the aortic arch is becoming more common, and the indications for it are increasing. We report our experience with this procedure, including life-table analysis of the long-term results. MATERIALS AND METHODS: We dilated 32 lesions in 29 patients. Early in our series, patients were referred primarily because of arm claudication or vertebrobasilar insufficiency. Subsequently, the indications were expanded to include inflow to left internal mammary-coronary artery bypass grafts, inflow to axillobifemoral bypass grafts, and inflow to dialysis fistulas in the upper extremity. A femoral artery approach was used in 18 patients and an axillary approach was used in 11. Clinical follow-up included evaluation of symptoms and bilateral measurements of peripheral pulses and blood pressure. Follow-up angiograms were obtained in nine patients. RESULTS: Eighteen of the lesions dilated were located in the left subclavian artery, eight were in the right subclavian artery, four were in the axillary or proximal brachial artery, and two were in the innominate artery. Interestingly, three of eight right subclavian arteries treated had an anomalous origin from the arch of the aorta. Initial technical success was 100%. All 29 patients had long-term follow-up of 4-88 months (mean, 36 months). In one patient, stenosis recurred 8 months after angioplasty. This patient subsequently had redilatation. Life-table analysis projected a 7.5-year cumulative primary patency rate of 96.6%. No cerebrovascular complications or embolic events occurred. CONCLUSION: Angioplasty of the great vessels is safe and effective, and the long-term results are favorable when compared with results after surgery. As a result, the indications for this procedure should be broadened.

Treatment of hemodialysis fistula pseudoaneurysms with detachable balloons: technique and preliminary results.

Pseudoaneurysm formation is commonly encountered during the life of a dialysis fistula. When these become excessively large or numerous, surgical revision of the graft has been the only treatment option. The authors have treated seven patients by using percutaneous placement of a detachable balloon to occlude a pseudoaneurysm of an upper extremity graft. In four cases the balloon was directed into the pseudoaneurysm from a femoral artery approach. In three cases a direct puncture was made into the pseudoaneurysm for placement of the balloon. The patients were followed up from 1 week to 7 months. Initial technical success was achieved in all seven cases with no complications. Thrombosis of two grafts occurred during the first week after the procedure: one because of herniation of the balloon out of the pseudoaneurysm and one for unknown reasons. One balloon was inadvertently punctured and deflated during subsequent dialysis. Treatment in the other four cases was successful, as evidenced by no further enlargement of the pseudoaneurysms. Direct puncture of the pseudoaneurysm simplifies the procedure and probably decreases the likelihood of balloon herniation because of the orientation of the balloon.

Thromboembolectomy with the transluminal extraction catheter (TEC) as an adjunct to thrombolysis.

Multiple surgical and percutaneous interventional radiologic techniques have been used to restore blood flow in an acutely ischemic extremity. The transluminal extraction catheter (TEC) system was used as a mechanical thromboembolectomy device to supplement pharmacologic thrombolysis in one patient. In this case, 40 hours of direct intraarterial infusion of urokinase into the occluded vascular segments of a threatened lower extremity resulted in incomplete thrombolysis. Therefore, a 7-F TEC system was advanced percutaneously through the occluded vessels with restoration of luminal patency in all vessels treated. No distal embolization occurred. The TEC system facilitated prompt recanalization of vessels occluded by acute thrombus superimposed on atherosclerotic disease.

Normal venous anatomy and collateral pathways in upper extremity venous thrombosis.

Collateral pathways are well known in superior vena cava occlusion but not in axillary or subclavian vein occlusion, even though these occlusions are becoming more common. In a series of 127 arm venograms obtained for suspected venous thrombosis, the authors found 32 instances of subclavian or axillary vein occlusion. The authors reviewed the cases for site of occlusion and definition of collateral pathways. In 15 cases, the occlusion was in the subclavian vein, with collateral flow established chiefly via veins in the neck. Ten cases of axillary vein occlusion with chest wall collateral pathways were identified. Seven cases could not be categorized. Knowledge of these pathways is useful for accurate interpretation of upper extremity venograms. A more thorough understanding of venous pathways in the upper body may aid in the treatment of patients with chronic disease and longterm indwelling central venous catheters.

Circumferential rupture of an angioplasty balloon with detachment from the shaft: case report.

Rapidly evolving angioplasty balloon techniques need continual evaluation for the type or frequency of balloon-related complications. We recently encountered a case where a new narrow shaft polyethylene terephthalate balloon completely separated from the catheter following circumferential rupture. The balloon was successfully retrieved using grasping forceps and a basket. Patterns of balloon rupture and subsequent management are discussed. Problems of this type were more frequent in the early days of balloon angioplasty, but have since become rare. Close surveillance of new low profile balloons is recommended to determine whether this represents an isolated occurrence or a return to the earlier experience.

Real-time ultrasound for the detection of deep venous thrombosis.

PURPOSE: Accurate diagnosis of deep venous thrombosis (DVT) is a clinical problem in emergency practice. A prospective trial was conducted comparing real-time ultrasound with contrast venography in the diagnosis of proximal DVT. METHODS: Seventy patients whose clinical presentations mandated diagnostic evaluation for DVT had real-time ultrasound of the involved leg followed by contrast venography. Initial readings of ultrasound and venography were compared with each other and with final readings to assess reliability of interpretation. RESULTS: Final ultrasound readings agreed with final venogram readings in all patients. Negative initial ultrasound readings agreed with final venogram readings in 56 of 56 patients (negative predictive value, 100%; 95% confidence interval, 94 to 100). Eighteen patients had positive initial ultrasound readings compared with 14 who had positive final venogram readings (positive predictive value, 78%; 95% confidence interval, 55 to 91). CONCLUSION: Negative real-time ultrasonography reliably excludes proximal DVT. Positive ultrasound reliably diagnoses proximal DVT only in experienced hands.

Results and complications of angioplasty in fibromuscular disease.

Percutaneous transluminal angioplasty (PTA) was used to treat 66 patients with 85 renal artery stenoses due to fibromuscular dysplasia. The hypertension was refractory to medical management in 46 patients, and the initial success rate was 100%. Clinical follow-up has been obtained in all patients, who were followed for as long as 121 months. The recurrence rates were 8% of lesions and 10% of patients. Cumulative patency rate predicted for 10 years was 87.07%. The mean systolic pressure decreased by 52 mm Hg and the mean diastolic pressure decreased by 35 mm Hg in response to treatment. Twenty-six patients (39%) were cured, 39 (59%) were classified as improved, and one (2%) did not respond to PTA. Fourteen of the patients also had elevated blood urea nitrogen and creatinine levels. Renal function was improved in 86% of the patients and stabilized in 14% of the patients. Analysis of the long-term results suggests that PTA should be the initial treatment for choice of patients with fibromuscular dysplasia in the renal arteries.

Results and complications of angioplasty in aortoiliac disease.

Percutaneous transluminal angioplasty was used to treat 340 aortoiliac lesions in 200 patients who were followed for as long as 90 months (mean, 28.7 months; median, 23 months). The initial success rate was 94.7% for lesions and 93.0% for patients. The indications for percutaneous transluminal angioplasty included claudication in 117 patients (58.5%), rest pain or ischemic night pain in 47 (23.5%), limb salvage in 33 (16.5%), and aiding in wound healing in three (1.5%). In the series, 70% of the patients had two or more cardiovascular risk factors. Angioplasty was initially unsuccessful in 14 patients, and 10 patients were lost to follow-up. Follow-up was obtained in 176 patients. The long-term results were analyzed using the life table method to determine cumulative patency. Fourteen patients were considered failures because of recurrent disease or symptoms. The projected 7.5-year cumulative patency rate was 85%. When the response to redilatation was considered, the projected 7.5-year cumulative patency rate was 92%. The results indicate that percutaneous transluminal angioplasty can successfully correct aortoiliac lesions and provide a long-term benefit for as long as 7.5 years.

New balloon-through-balloon angioplasty technique for the treatment of segmental lesions.

A new balloon catheter on a wire that can be passed through standard 5- and 7-F angioplasty catheters recently became available. This capability allowed the authors to dilate segmental arterial lesions in which different balloon sizes were required without multiple catheter exchanges. Six patients were successfully treated with this technique, without complications.

Vascular injury following foreign body perforation of the esophagus. Review of the literature and report of a case.

Esophageal perforation resulting from foreign body ingestion is a rare occurrence. Most of the complications associated with this event, such as retroesophageal abscess, mediastinitis, pericarditis, pneumothorax, and pneumomediastinum, are widely recognized. However, little attention has been directed to the possibility of vascular injury caused by the perforating object. Isolated case reports have described significant morbidity and mortality subsequent to major vascular trauma resulting from an esophageal foreign body, usually emphasizing the presence of a "signal" hemorrhage from the gastrointestinal tract as a key to diagnosis. This report describes a case of esophageal perforation caused by an ingested fishbone that resulted in significant aerodigestive hemorrhage, possibly as the result of an unusual isolated vascular injury. The literature on vascular trauma following foreign body perforation of the esophagus is reviewed, and suggestions for the diagnosis and treatment of these dreaded complications are made.