Controlled trials of radiologic contrast media: issues in quality assessment and synthesis.
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Contrast Media↗
Biomedical subjects
M L Kinnison
Publications and source records attributed to M L Kinnison.
Left lobe of the liver: percutaneous biliary drainage.
Left-sided biliary drainage was performed in 89 of 678 (13%) patients undergoing percutaneous biliary drainage procedures during a 9-year period. The most common indication was Klatskin tumor, followed by sclerosing cholangitis, carcinoma of the gallbladder, postoperative benign stricture, and metastasis to the porta hepatis. Left-duct drainage was successful in 82 of the 89 patients (92%) in whom it was attempted. One patient sustained a major hemorrhage from a hepatic artery aneurysm, which was managed with transcatheter embolization.
Bile Ducts↗
Results of randomized controlled trials of low-versus high-osmolality contrast media.
The authors reviewed 100 randomized controlled trials (RCTs) conducted in humans to compare safety or efficacy of new low-osmolality contrast media (LOM) with that of high-osmolality contrast media (HOM). Findings of the 43 RCTs judged to be of the highest quality suggest that the efficacy of LOM in imaging is equal or superior to that of HOM for all routes of administration. Heat sensation occurred less often with LOM for all routes and pain occurred less often with LOM for intraarterial routes. No differences were seen in nephrotoxicity or in frequency of nausea, vomiting, urticaria, bronchospasm, laboratory test abnormalities, or neurologic events. Greater cardiovascular changes were seen with HOM, including increased or decreased heart rate, increased left ventricular end-diastolic pressure, decreased systolic pressure, and QT prolongation, depending on route of administration. To demonstrate whether a reduction in clinically significant adverse outcomes truly occurs with LOM, trials will need to enlist larger numbers of patients and employ appropriate outcome measures. Future trials should stratify patients according to their risk of adverse reactions to provide better information about benefits of LOM in low- versus high-risk patients.
Clinical Trials as Topic↗
Quality assessment of randomized controlled trials of contrast media.
Numerous randomized controlled trials (RCTs) have been conducted to define the relative benefits of low-osmolality contrast media (LOM) and high-osmolality contrast media (HOM). Because of the clinical and economic significance of the conclusions drawn from these RCTs, the authors used a standardized instrument to evaluate the quality of study design and data analysis of 100 RCTs published between 1982 and 1987 that compared LOM and HOM. The mean quality score (+/- standard deviation) was 39 +/- 12 (maximum possible score, 100). The largest number of patients studied in any RCT was 435; the smallest was five. A majority of the RCTs received high scores on three attributes of quality, intermediate scores on seven, and low scores on nine. These results underscore the difficulty of designing, performing, analyzing, and reporting high-quality RCTs. Nevertheless, limitations in study design and data analysis need to be considered when interpreting results of these RCTs. Future RCTs comparing LOM and HOM should be performed with greater attention to basic elements of good study design and data analysis.
Clinical Trials as Topic↗
Blue toe syndrome: treatment with anticoagulants and delayed percutaneous transluminal angioplasty.
The spontaneous onset of a painful unilateral blue toe is usually caused by fibrinoplatelet microemboli arising from an upstream stenotic or occlusive lesion of the iliac or femoral artery. This constellation of findings is referred to as the blue toe syndrome (BTS). In 12 patients who experienced 14 spontaneous episodes of BTS, angiography demonstrated 15 proximal atherosclerotic arterial lesions, which were presumed to be the source of the microemboli. Fourteen of the 15 lesions were short-segment stenoses or occlusions distal to the aortic bifurcation. Six lesions were treated with antiplatelet or anticoagulant drugs followed by delayed percutaneous transluminal angioplasty (PTA) 6-12 weeks later. Three lesions were treated with surgical bypass, three with long-term anticoagulation, and one with transcatheter clot aspiration and immediate PTA. Two were treated with immediate thrombolytic therapy and had embolic complications. Antiplatelet and anticoagulant therapy followed by delayed PTA may be an effective alternative to surgery for treating BTS.
Adult↗
Reducing the cost of using contrast media: a look at discarded volumes.
A study of the volume of radiopaque contrast media (ROM) discarded during angiographic procedures was conducted at one tertiary care teaching hospital to evaluate the potential cost savings from reducing that volume. Volumes of ROM used and discarded during 31 cerebral angiographic procedures and 16 percutaneous transluminal coronary angioplasties (PTCAs) were analyzed. An average of 98 mL of ROM was discarded during cerebral angiography and 175 mL during PTCA. When low-osmolality contrast media (LOM) were used, the cost of discarded ROM was 15.8% of the technical charge for cerebral angiography and 21.5% for PTCA. If LOM were used, a savings of $11,000 per year could be achieved if 80-mL, rather than 100-mL, bottles were used for cerebral angiography and $35,000 per year if a single 300-mL bottle with inverted-Y tubing were used, rather than two 200-mL bottles currently employed for PTCA. Substantial savings could be realized by modifying technical procedures and by increasing the range of bottle sizes in which ROM are marketed.
Angiography↗
Streamlining operation of an admitting service for interventional radiology.
The authors describe how operations of an inpatient admitting service for interventional radiology were improved by developing a clinic and hiring a physician's assistant. The service, begun in 1982, was managed by a senior radiologist and fellows. Because of increasing admissions (from a mean of 52 per year in 1982-1985 to 110 per year in 1985-1987), a 1/2-day, twice-weekly clinic was created in 1985 to evaluate new patients and perform follow-up examinations. In 1986 a physician's assistant was hired to assist in the clinic and during patient admissions. Use of the clinic and physician's assistant streamlined patient flow and management during hospitalization. This resulted in a decrease in mean length of stay for patients undergoing angioplasty (from 3.74 days in 1982-1983 to 2.41 days in 1986-1987). This decrease means cost savings for the hospital under the prospective payment system. Other benefits include improved physician-patient relationships and follow-up, new patients for colleagues (15% of patients had anatomy unsuitable for interventional procedures and were referred to staff surgeons), and increased professional fees.
Angioplasty, Balloon↗
Contrast medium-induced adverse reactions: economic outcome.
Because the cost of managing an expected greater number of adverse reactions when high-osmolality contrast media (HOM) are used could offset the higher material cost of low-osmolality contrast media (LOM), a prospective study was done of 795 inpatients undergoing any of four procedures involving intravascular injection of HOM: cardiac catheterization, peripheral angiography, head computed tomography (CT), or body CT. The resources used in managing HOM-induced adverse reactions were measured, and the costs of these resources were estimated. Four hundred five patients (51%) had adverse reactions. Reactions were grouped into three classes according to their severity. Class 1 (mild) reactions occurred in 358 patients (45%), class 2 (moderate) reactions occurred in 44 patients (6%), and class 3 (severe) reactions occurred in three patients (0.4%). Ninety-nine patients (12%) consumed resources as a result of an adverse reaction. The average cost of these resources per patient undergoing examination was $1.07 to the radiology department, $5.83 to the hospital, and $12.93 to a charge-paying insurer. Mean (+/- standard deviation) cost to the hospital for managing class 1, class 2, and class 3 reactions were $2.52 +/- $5.33, $24 +/- $54, and $910 +/- $749, respectively. By comparison, the difference in material cost of HOM versus LOM ranged from $93 for body CT to $179 for cardiac catheterization. Even if LOM were to induce no adverse reactions, the increased material cost associated with universal substitution of LOM for HOM would be greater than the expected cost of managing adverse reactions when HOM are used.
Adult↗
Use of low-osmolality contrast media in a price-sensitive environment.
Over the past 3 years, three radiographic contrast media that are lower in osmolality than traditional contrast media have become available in the United States. These lower osmolality media have been reported to produce fewer adverse reactions than the higher osmolality media, but they cost 10 to 20 times more than higher osmolality media. To explore hospital and physician decision-making regarding the use of lower osmolality media in the increasingly price-sensitive health-care environment, we surveyed the 40 hospitals in the United States that received the most funding from the National Institutes of Health in 1985. Radiologists in 27 (68%) of the hospitals responded. Of these, 93% believed lower osmolality media improve the quality of patient care. However, nearly half of responding institutions limited the use of lower osmolality media. On average, in 1986 lower osmolality media were used in 9% of procedures in which contrast media were injected intravascularly. The decision to limit use was made primarily by radiologists, rather than hospital administrators, and was based on concerns regarding the high price of lower osmolality media. Twelve respondents had developed guidelines for appropriate use of lower osmolality media, but only 25% of these had developed mechanisms to ensure or increase compliance with those guidelines. Only one respondent (4%) reported that he routinely informs patients of the issues and tradeoffs involved in deciding whether to use lower or higher osmolality media. We conclude that cost is an important factor in physicians' and hospitals' choices of contrast media and that increased attention should be given to defining appropriate procedures to follow when informed consent is obtained for the use of contrast material.
Attitude of Health Personnel↗
Long-segment femoropopliteal stenoses: is angioplasty a boon or a bust?
Analysis of 193 femoropopliteal angioplasties demonstrated patency rates in the stenotic group of 75.5% at 6 months and 54.4% at 54 months. The patency rates for the occlusive group were 93.7% at 6 months and 72.9% at 54 months; these rates were significantly better than those in patients with stenoses. A group of 14 patients with long-segment (greater than 7 cm) stenosis had the highest risk of early failure, with a 6-month patency of 23.1%. After removal of the long-segment stenosis group from the results, there were no significant differences between the long-term patencies for stenotic and occlusive lesions. If angioplasty of long stenoses is attempted, a high initial success rate but early failure should be anticipated.
Angioplasty, Balloon↗
Upper-extremity venography using digital subtraction angiography.
Venography to evaluate the patency of upper-extremity veins was performed with digital subtraction angiography (DSA) and conventional angiography. Venous thrombosis was easily diagnosed, and the innominate veins and superior vena cava were more easily visualized using DSA. Iodine concentration for DSA was one-third that of conventional venography, and the examination time was reduced by 50% using DSA. Patient comfort and acceptance were greater with DSA. DSA is a superior technique for upper-extremity vein evaluation in cooperative patients.
Adult↗
Comparison of recurrent varicocele anatomy following surgery and percutaneous balloon occlusion.
Venography of 44 recurrent varicoceles in 37 patients demonstrated different anatomical patterns of recurrence in surgical patients (26) compared to those treated by percutaneous balloon occlusion (18). The 3 types of patterns identified included parallel, renal vein and transcrotal collateral pathways. Virtually all surgical recurrences were owing to mid retroperitoneal (27 per cent) or low (inguinal) parallel collaterals (58 per cent). The majority of post-balloon occlusion recurrences were due to either high retroperitoneal parallel (44 per cent) or renal vein collaterals (28 per cent). Surgical recurrences were treated easily with percutaneous balloon occlusion. However, 39 per cent of the patients with recurrences following balloon embolization were not anatomical candidates for repeat percutaneous occlusion. We conclude that venous collaterals are identified easily by renal venography, and knowledge of these collaterals is helpful in planning further surgical or radiological treatment.
Embolization, Therapeutic↗
In situ saphenous vein bypass grafts: angiographic evaluation and interventional repair of complications.
In situ saphenous vein grafts are being used with increasing frequency for bypass procedures involving the femoral and popliteal arteries. Complications of these procedures include anastomotic stenoses and persistent arteriovenous fistulae that may result in failure of the graft. Balloon angioplasty and embolotherapy with detachable balloons were employed successfully in three or four recent cases of patients with complications from in situ grafts. Tailored angiography is essential for evaluating in situ grafts, and interventional techniques are extremely useful for managing complications.
Aged↗
Percutaneous spermatic vein occlusion: evaluation of sclerosing agents in experimental animals.
The 5%-20% rate of recurrence of testicular varicoceles after embolotherapy has been a persistent clinical problem. Three sclerosing agents--sodium tetradecyl sulfate 3%, absolute ethanol, and 100 degrees C contrast material--were evaluated in canine spermatic veins for degree and durability of venous occlusion. Pathologic examination for perivenous, pulmonary, and neural changes was performed. Both sodium tetradecyl sulfate and absolute ethanol were effective sclerosants, but sodium tetradecyl sulfate was technically easier to use. The use of a sclerosant in conjunction with balloons or coils is the safest, most effective technique for occluding variococeles and minimizing postembolotherapy recurrences.
Animals↗
Long-term results of superficial femoral artery angioplasty.
Short-term results of superficial femoral artery and popliteal percutaneous transluminal angioplasty have been good, but long-term results and factors influencing long-term patency are less commonly reported. One hundred thirty-seven superficial femoral artery angioplasties with follow-up for 54 months were reviewed. The 4-year patency for stenoses was 61% and for occlusions was 68%. If the initial result was clinically successful, the 4-year patency was not influenced by the quality or patency of runoff or by the length of the occlusion. Nineteen patients returned for redilatation, eight of whom had developed new lesions. Patency was adversely affected in patients with diabetes or with long-segment stenoses. Modifications of equipment and technique that may improve long-term patency rates are discussed.
Angioplasty, Balloon↗
Inpatient admissions for interventional radiology: philosophy of patient management.
As an alternative to performing interventional radiology on inpatients under the care of internists and surgeons, the authors have established a cardiovascular radiology admitting service for well-screened, elective patients. The patients are admitted under the care of a cardiovascular radiology fellow and a staff physician. From April 1982 to December 1983, 133 patients were admitted to the service. Patients are cared for in a surgical ward or in an intermediate unit, as determined by the clinical situation. Advantages of this approach include a broader patient referral base, improved rapport with clinical colleagues and patients, improved follow-up data, and rapid evaluation and treatment, resulting in short hospital stays. The major disadvantages involve the commitment of time and staff necessary to provide quality care. The concept of the interventional radiologist in the role of admitting physician has important implications in terms of negotiations for additional financial compensation, commensurate with the skill and time required for performing these procedures and caring for the patient.
Angioplasty, Balloon↗
Silicone biliary stents for percutaneous management of biliary obstruction.
Silicone tubes in 2-F increments from 12 to 20 F were developed for long term external-internal drainage of benign and malignant biliary obstructions. Passed coaxially over Teflon catheters and a guidewire, the silicone stents were softer and had larger sideholes than conventional drainage tubes. Once the acute track had matured (two weeks or longer), a silicone stent, 2 F larger than the preceding one, could be placed at each succeeding tube change. We have placed these tubes in 50 patients, 24 of whom had initially placed percutaneous catheters and 26 of whom had surgically placed stents. These tubes remain patent at least as long as conventional catheters and all patients have reported increased comfort using these catheters compared with standard ones.
Catheterization↗
Nonoperative management of benign postoperative biliary strictures.
Selected benign biliary strictures can be treated safely and successfully by percutaneous balloon dilatation. Primary biliary strictures appear to be less responsive to balloon dilatation alone and require stenting with large catheters (16-20 F) for several months to permit scarring around the catheter. A long period of healing around such a large-bore stent is crucial to the success of such treatment. The most important physiologic indicators for successful dilatation are a long period of stricture challenge with a catheter placed proximal to the dilated segment to allow bile to drain internally across the previously strictured segment, and a near anatomic result as demonstrated by cholangiogram.
Adolescent↗