Diagnostic imaging in the management of patients with possible cerebral venous thrombosis: a cost-effectiveness analysis.

PURPOSE: Imaging is crucial for management of patients with possible cerebral venous thrombosis (CVT). To evaluate the cost-effectiveness of different noninvasive imaging strategies in patients with possible CVT. METHODS: A decision model based on Markov simulations estimated lifetime costs and quality-adjusted life years (QALY) associated with the following imaging strategies: non-contrast CT (NCCT), NCCT plus CT venography (CTV), routine MRI without vascular imaging (R-MRI), and MRI with venography (MRV). The analysis was performed from a US healthcare perspective. Model input was based on best available and most recent evidence, including outcome data from the International Study on Cerebral Vein and Dural Sinus Thrombosis (ISCVT). Starting age was 37 years; both high and low pre-test probabilities of CVT were evaluated. Probabilistic sensitivity analyses (PSA) estimated model uncertainty. RESULTS: In the base-case analysis, NCCT and CTV were dominant over R-MRI and MRV. CTV led to incremental lifetime QALYs compared with NCCT (23.385 QALYs vs. 23.374 QALYs) at slightly higher lifetime costs ($5210 vs. $5057). In PSA, CTV was the strategy with the highest percentage of cost-effective iterations if willingness-to-pay (WTP) thresholds were higher than $13,750/QALY. Complying with contemporary WTP thresholds, CTV was thus identified as the most cost-effective strategy. When the pre-test probability was set to 50%, CTV was also preferred. CONCLUSION: In patients at the peak age of CVT incidence yet low clinical pre-test probability, diagnostic imaging with CTV is the most cost-effective strategy.

Catheter-Directed Thrombolysis Versus Pharmacomechanical Thrombectomy for Upper Extremity Deep Venous Thrombosis: A Cost-Effectiveness Analysis.

BACKGROUND: Upper extremity deep vein thrombosis represents (UEDVT) 2-3% of all deep vein thrombosis. Catheter directed thrombolysis (CDT) was replaced largely by pharmacomechanical thrombolysis (PMT) in our institution. In this study we compared the immediate and 1-year results as well as the total hospital costs between CDT and PMT in the treatment of UEDVT. METHODS: From 2006 to 2013, 55 patients with UEDVT were treated with either CDT or PMT at Helsinki University Hospital. Of them, 43 underwent thoracoscopic rib resection later to relieve phlebography-confirmed vein compression. This patient cohort was prospectively followed up with repeated phlebographies. CDT was performed to 24 patients, and 19 had PMT with a Trellis™ device. Clinical evaluation and vein patency assessment were performed with either phlebography or ultrasound 1 year after the thrombolysis. Primary outcomes were immediate technical success, 1-year vein patency, and costs of the initial treatment. RESULTS: The immediate overall technical success rate, defined as recanalization of the occluded vein and removal of the fresh thrombus, was 91.7% in the CDT group and 100% in the PMT group (n.s.). The median thrombolytic time was significantly longer in CDT patients than that in PMT patients (21.1 vs. 0.33 hr, P < 0.00001). There were no procedure-related complications. The 1-year primary assisted patency rate was similar in both the groups (91.7% and 94.7%). There were no recurrences of clinical DVT. The hospital costs for the acute period were significantly lower in the PMT group than those in the CDT group (medians: 11,476 € and 5,975 € in the CDT and PMT groups, respectively [P < 0.00001]). CONCLUSIONS: The clinical results of the treatment of UEDVT with CDT or PMT were similar. However, PMT required shorter hospital stay and less intensive surveillance, leading to lower total costs.

Clinical and health costs impact of progress in diagnosis and treatment in venous thromboembolic disease: evolution in 15 years.

BACKGROUND: The therapeutic and diagnostic approach in deep vein thrombosis (DVT) has changed enormously in the last two decades with the introduction of ultrasound, low-molecular-weight heparin (LMWH), and premature motion. The aim of this study is to evaluate these changes and analyze their clinical and economic aspects. METHODS: We registered all inpatients with a diagnosis of DVT during 1994 (n=110) and 2009 (n=75) and their sociodemographic and clinical features in a descriptive observational design. We performed a comparison of diagnostic techniques, length of stay, inpatient complications, and costs thus derived for both series, based on 2009 prices, so that we could get comparable results. RESULTS: Ninety-one percent of inpatients in 1994 were diagnosed by venography, whereas, in 2009, the diagnosis was based on clinical features, D-dimer, and ultrasound in 100% of patients. Inpatient treatment went from 7% LMWH in 1994 to 96% in 2009, and as outpatient from 82% acenocumarol to 90.6% LMWH. Complications decreased by 13.3%. Length of stay was 2.7 higher in 1994. Globally, the cost per patient decreased by 63.39%, based primarily on reduced length of stay. CONCLUSIONS: The current diagnostic and therapeutic approach in DVT allows for effective treatment, fewer complications, and a drastic reduction in inpatient costs.

Current treatment status and medical costs for hemodialysis vascular access based on analysis of the Korean Health Insurance Database.

BACKGROUND/AIMS: The Republic of Korea is a country where the hemodialysis population is growing rapidly. It is believed that the numbers of treatments related to vascular access-related complications are also increasing. This study investigated the current status of treatment and medical expenses for vascular access in Korean patients on hemodialysis. METHODS: This was a descriptive observational study. We inspected the insurance claims of patients with chronic kidney disease who underwent hemodialysis between January 2008 and December 2016. We calculated descriptive statistics of the frequencies and medical expenses of procedures for vascular access. RESULTS: The national medical expenses for access-related treatment were 7.12 billion KRW (equivalent to 6.36 million USD) in 2008, and these expenses increased to 42.12 billion KRW (equivalent to 37.67 million USD) in 2016. The population of hemodialysis patients, the annual frequency of access-related procedures, and the total medical cost for access-related procedures increased by 1.6-, 2.6-, and 5.9-fold, respectively, over the past 9 years. The frequency and costs of access care increased as the number of patients on hemodialysis increased. The increase in vascular access-related costs has largely been driven by increased numbers of percutaneous angioplasty. CONCLUSION: The increasing proportion of medical costs for percutaneous angioplasty represents a challenge in the management of end-stage renal disease in Korea. It is essential to identify the clinical and physiological aspects as well as anatomical abnormalities before planning angioplasty. A timely surgical correction could be a viable option to control the rapid growth of access-related medical expenses.

Diagnostic tests for deep vein thrombosis. Clinical usefulness depends on probability of disease.

We review the general principles that govern the clinical utility of diagnostic tests, particularly with respect to the diagnosis of deep vein thrombosis (DVT). We stress the importance of clinical probability of disease, which strongly influences the positive predictive value (true-positive rate) and negative predictive value (true-negative rate) of all diagnostic tests. In selecting a diagnostic procedure for DVT, the physician must first consider the clinical probability of disease and then the local accuracy of the test employed and its cost-effectiveness. In 75% to 80% of patients suspected to have DVT, clinical management can be based on the results of noninvasive tests, such as ultrasonography or impedance plethysmography (IPG), rather than venography. Ultrasonography has clear advantages over venography with respect to cost and patient comfort, and it defines the anatomic extent of the thrombus. It should be considered the new diagnostic standard for symptomatic DVT. Despite recent reports of lower sensitivity than previously reported, IPG remains an acceptable alternative to ultrasonography for symptomatic DVT in selected patients. Even if the recently reported lower sensitivity proves to be accurate, the probability of adverse clinical outcomes as a result of overlooked disease is still extremely low in patients with a low probability of DVT. The negative predictive value of IPG under these circumstances approaches 99%. Impedance plethysmography is also useful in patients with a high probability of DVT, in whom the positive predictive value may be as high as 97%. When the findings of IPG (or ultrasonography) are at variance with a strong clinical impression, venography should be considered, especially when there is a high clinical probability of disease and a negative noninvasive test result.

Comparison of four strategies for diagnosing deep vein thrombosis: a cost-effectiveness analysis.

PURPOSE: Four strategies for the diagnosis of deep vein thrombosis have been validated recently. The strategies use various combinations of assessment of a patient's clinical probability of having deep venous thrombosis, serial lower limb venous compression ultrasonography, and measurement of plasma D-dimer levels. We compared the cost-effectiveness of these diagnostic strategies. MATERIALS AND METHODS: We performed a formal cost-effectiveness analysis using a decision-analysis model. Outcomes considered were costs per patient, 3-month quality-adjusted survival, number of lives saved per 1,000 patients, and incremental costs per quality-adjusted life-year (QALY) gained. RESULTS: Under baseline conditions, with a 24% prevalence of deep vein thrombosis in tested patients, the effectiveness of all strategies was similar (4.6 to 4.8 lives saved per 1,000 patients managed). The most expensive strategy was serial ultrasound (repeat ultrasound on day 7 in all patients with a normal initial ultrasound) at a cost-effectiveness of $10,716 per additional QALY. Performing a repeat ultrasound only in patients with an elevated D-dimer level (serial ultrasound with D-dimer) was somewhat less expensive at $10,281 per additional QALY. Taking clinical probability into account by repeating ultrasound only in patients with an intermediate clinical probability of deep vein thrombosis (risk-based serial ultrasound) yielded further savings and cost $10,090 per additional QALY. The least expensive and most cost-effective option was to perform D-dimer as the initial test, followed by a single ultrasound if the D-dimer level was abnormal, and by phlebography in patients with a normal ultrasound and a high clinical probability of deep vein thrombosis (D-dimer with risk-based single ultrasound) at $8,897 per additional QALY. This strategy allowed a 17% reduction in incremental costs compared with the most expensive algorithm and reduced resource consumption (70 ultrasound procedures per 100 patients managed vs 130 to 170 with the other diagnostic strategies). CONCLUSIONS: Combining clinical probability and D-dimer with a single ultrasound in the diagnostic workup of patients with possible deep vein thrombosis is highly cost-effective, allowing a reduction in costs and resource use without any substantial increase in mortality. Serial ultrasonography is less cost-effective.

Cost effectiveness of diagnosis of deep vein thrombosis in symptomatic patients.

BACKGROUND: The most widely used noninvasive test for deep vein thrombosis is Doppler ultrasonographic imaging of the lower extremities. The best evaluated of the noninvasive approaches are ascending contrast venography, impedance plethysmography, Doppler ultrasonography with B-mode imaging. Economic evaluation is aimed at helping decision makers to reach their goal of maximizing the health of the population served, subject to the available resources. METHODS: The data that provided the basis for this cost effectiveness analysis were derived from a prospective study of approximately 500 patients referred to a regional thromboembolism program with a first episode of clinically suspected deep vein thrombosis. The application of cost effectiveness analysis to the diagnosis of deep vein thrombosis is readily accomplished using cost minimization. This cost effectiveness technique makes it possible to rank the diagnostic approaches from "worst" to "best", with the best approach defined as that which accomplishes the desired health effect at minimum cost. Effectiveness (health benefit) may be defined in this context as the number or proportion of patients with deep vein thrombosis correctly identified by objective testing or, the number or proportion in whom treatment was correctly withheld. RESULTS: Clinical diagnosis is cost ineffective; $1,590,784 Canadian, $2,624,220 US. Outpatient diagnosis using noninvasive testing was the most cost effective. Serial Doppler ultrasonography is more costly ($618,265 Canadian, $1,326,180 US) than serial impedance plethysmography ($527,165 Canadian, $1,052,880 US). Combined Doppler ultrasonography and serial impedance plethysmography offers a less costly strategy ($551,065 Canadian, $1,124,580 US) than serial ultrasonography alone. DISCUSSION: Objective testing is mandatory. Outpatient testing is preferred, avoiding unnecessary hospital admissions. Noninvasive testing is the most cost effective. The most widely used test, serial Doppler ultrasonography, is less cost effective than serial impedance plethysmography. The combined approach of initial Doppler ultrasonography followed by serial impedance plethysmography combines the advantage of an initial ultrasound image with less costly serial impedance plethysmography.

Suspected deep vein thrombosis. Management by impedance plethysmography.

Controversy exists as to whether patients suspected of having deep vein thrombosis (DVT) can be studied safely without venography, with its attendant expense, inconvenience, and potential risk. We used impedance plethysmography (IPG) in 1,464 consecutive patients suspected of having DVT, with 96% of these patients with normal IPGs, there were no fatal pulmonary emboli (PE). The incidence of nonfatal PE was 1%. In 284 outpatients suspected of having DVT, but discharged without treatment because of normal IPGs, only one patient returned with subsequent symptoms of DVT (0.4%). Noninvasive testing with IPG is a safe and highly cost-effective alternative to venography for routine management of patients suspected of DVT.

Cost-effectiveness of prophylaxis in total hip replacement.

A theoretical analysis was performed regarding the cost-effectiveness in terms of lives saved (reduction of fatal pulmonary embolism [PE]) and in terms of money (dollars spent for prevention and treatment) of seven strategies in the management of venous thromboembolic disease in patients over 39 years of age undergoing elective total hip replacement (THR). Strikingly, this theoretical analysis suggests that low-dose warfarin combined with clinical surveillance of deep vein thrombosis would reduce the incidence of fatal PE from 20 per 1,000 patients to 4 per 1,000 patients and simultaneously reduce the charges for venous thromboembolic disease from $550,000 to about $400,000 per 1,000 patients. Based on this analysis, we strongly recommend this measure on a routine basis. Adding venography or duplex sonography routinely to this prophylactic regimen would, in this theoretical analysis, reduce the incidence of fatal PE from 4 per 1,000 patients to 0.15 per 1,000, but adds charges of $200,000 per extra life saved in the case of routine venography and $50,000 in the case of routine sonography. Low-dose warfarin prophylaxis combined with routine sonography does not generate more charges than no prophylaxis with no screening while drastically reducing the incidence of fatal PE from 20 to 0.3 per 1,000 patients. Where duplex sonography is not easily available, a 12-week postoperative course of low-dose warfarin for every patient with no routine screening will be efficacious in reducing fatal PE and as cost-effective.

Can the results of treatment of deep venous thrombosis be improved by combining surgical thrombectomy with regional fibrinolysis?

A new mode of treatment of extensive acute and subacute deep venous thrombosis of the lower extremities is introduced. For this purpose the beneficial effects of surgical thrombectomy and of thrombolysis with streptokinase are combined during the course of a single surgical intervention. Rapid-flow regional perfusion is the vehicle used for administration of streptokinase and probably represents the third arm of this therapeutic approach by adding a hemodynamic wash-out effect. Because the thrombolytic agent is rinsed out of the circuit at the end of regional perfusion the usual side effects and contra-indications of this drug are avoided. Early and late results of this treatment are assessed clinically and with repeat venograms in a group of 9 patients. Highly satisfactory results were obtained in 6 patients with complete anatomical and functional restoration of deep veins along their entire length in three cases. It is felt that continued use of this method is warranted and that the results of treatment of deep venous thrombosis can thus be improved.

Social and economical effectiveness of non-invasive vascular examinations in the clinical management of thrombo-embolic disease.

In a retrospective study about the seven past years in our Hospital Center, we found that the number of X-ray venographies increased strongly from year to year until non-invasive examinations (Doppler and plethysmography and Real-time B-mode sonography) were widely used with a high sensitivity and specificity level. A new diagnostic algorhythm was then introduced in the clinical practice, X-ray venography being required mainly when an invasive treatment (thrombectomy, thrombolysis, vena cava interruption...) was planed, but not for the positive diagnosis. Thereafter, the number of X-ray venographies decreased. In that way, the cost of the diagnosis was significantly reduced as were risks and discomfort for the patient.

[Ultrasound study before surgery of varicose veins]. / Ultraschalluntersuchung vor Varizenchirurgie.

Ultrasonographic investigation of the various forms of chronic venous insufficiency has substantial advantages compared to diagnosis with the competing phlebogram, particularly preoperatively. Important details such as side branches in the region of the groin, course variations of the small saphenous vein and insufficiency of the perforators in the lower leg are sometimes missed in the antegrade phlebogram. However, it is absolutely necessary to take these into consideration in order to attain a substained good result of surgery. With adequate qualification of the investigator and using all ultrasound techniques, diagnosis by sonography is better than by means of antegrade phlebogram. There are clear specifications for the documentation. With regard to costs and time required, ultrasonographic investigation of chronic venous insufficiency is superior to the antegrade phlebogram and can be repeated at any time.

[Irradiation of the patient and its costs in the usual diagnostic procedures for disk hernia. Radiculography, spinal phlebography and tomodensitometry]. / Etude de l'irradiation du patient et du coût dans les procédures diagnostiques usuelles des hernies discales. Radiculographie, phlébographie rachidienne et tomodensitométrie.

Three methods are currently employed for the diagnosis of sciatica due to disc lesions: radiculography, spinal phlebography, and computed tomography. Though their indications vary according to the author, it seemed worthwhile to compare radiation delivered by each of them, because of the often young age of the patients. Dosimetric studies using a Rando Phantom enabled calculation of doses to the skin, spinal cord, and gonads. Results indicated that low doses were delivered by the scanner, relatively high doses by spinal phlebography, and intermediate doses by radiculography. These findings suggest that the initial examination preoperatively in cases of simple sciatica due to herniated disc should be a CT scan whenever possible. Phlebography, on the contrary, and particularly in young women, should be used only exceptionally, as a result of the high doses delivered to the ovaries even during technically simple explorations.

A cost-effectiveness analysis of diagnostic algorithms of deep vein thrombosis at the emergency department.

INTRODUCTION: Suspected cases of deep vein thrombosis are common at emergency departments and they often require extensive and costly diagnostic testing. The objective of this study was to evaluate whether a diagnostic algorithm based upon pre-test probability and D-dimer in diagnosing deep vein thrombosis may be cost-effective from a societal perspective in a Swedish setting. MATERIAL AND METHODS: The cost-effectiveness of two alternative diagnostic algorithms were calculated using decision analysis. An algorithm which out ruled deep vein thrombosis among low probability patients with negative D-dimer was compared to a traditional algorithm including compression ultrasonography and/or contrast venography for all patients. For sensitivity analysis, a third reversed algorithm, where D-dimer was followed by pre-test probability, was analyzed. Estimates of probabilities were obtained from a prospective management study, including 357 outpatients with clinical suspicion of deep vein thrombosis. Direct costs were estimated using prices from Scania, Sweden. Indirect costs were estimated using time spent at the local emergency department and gross average wages in Sweden. RESULTS: The total cost of the pre-test probability and D-dimer algorithm was estimated to euro406 per patient and the traditional algorithm was estimated to euro581 per patient. Reversing the order of the score and test resulted in an estimate of euro421 per patient. CONCLUSION: At no significant difference in diagnostic efficacy the algorithm based upon pre-test probability and D-dimer was cost-effective, while the reversed algorithm and diagnostic imaging for all patients were not.

CT lower extremity venography in suspected pulmonary embolism in the ED.

The purpose of this study was to evaluate the added benefit of computed tomography lower extremity venography (CTLV)--performed following CT pulmonary angiography (CTPA)--in the emergency department (ED) patient suspected of pulmonary embolism (PE). A retrospective review of 427 consecutive patients having both CTPA and CTLV performed to evaluate patients suspected of PE at two community hospitals was conducted. Three-month follow-up was performed on all patients to ensure that no case of PE or deep venous thrombosis (DVT) was missed. Forty patients were positive for PE, and 11 were positive for DVT. There were 6 CTPA studies read as indeterminate for PE and 11 CTLV studies indeterminate for DVT. Only 1 patient was positive for DVT, who did not have a concurrent PE identified by CTPA. The estimated charges for detecting the single case of isolated DVT was 206,400 US dollars. In our ED setting, the additional benefit of adding CTLV to the standard ED work-up of PE was minimal.

Optimizing, diagnostic, and therapeutic strategies using decision-theoretic planning: principles and applications.

OBJECTIVE: Decision-theoretic planning is a new technique for selecting optimal actions. The authors sought to determine whether decision-theoretic planning could be applied to medical decision making to identify optimal strategies for diagnosis and therapy. METHODS: An existing model of acute deep venous thrombosis (DVT) of the lower extremities--in which 24 management strategies were compared--was converted into a set of conditional-probabilistic actions for use by the DRIPS decision-theoretic planning system. Actions were grouped into an abstraction/decomposition hierarchy. A utility function was defined in accordance with the existing DVT management model to incorporate the costs and risks of the diagnostic tests and treatments. RESULTS: From 18 primitive actions (such as "perform venography" and "treat if venography shows thigh DVT"), a total of 312 possible concrete plans were encoded within the abstraction/decomposition hierarchy. The DRIPS planning system used abstraction techniques to eliminate 136 possible plans (44%) from consideration. It determined that, given the parameters specified, the most cost-effective management strategy was "no tests, no treatment." This result differed from the published result of "perform ultrasonography, treat if positive." In reviewing the original article, it was determined that DRIPS had revealed an error in the manually constructed decision trees used in that manuscript. At values of $75,000 and greater for the cost of death, the optimal strategy became "impedance plethysmography (IPG), don't wait, perform venography if IPG is positive, and treat only if venography shows thigh DVT." CONCLUSION: Decision-theoretic planning is applicable to medical decision making and may be an extremely useful technique for complex decisions. The use of inheritance abstraction makes the technique computationally tractable for complex planning problems, and the modular nature of the data entry may help eliminate errors that appear in manually encoded decision trees.

Therapeutic and economic implications of emergency department evaluation for venous thrombosis.

Records of 160 emergency department patients with lower extremity complaints were reviewed to determine the economic and therapeutic impact of noninvasive venous impedance testing. Venograms obtained in 86 extremities were used to determine diagnostic accuracy. The incidence of pulmonary thromboembolic events, postphlebitic syndrome and complications of anticoagulation was ascertained. Outflow impedance testing correctly identified all patients with deep venous thrombosis and overall diagnostic accuracy was 95% (41/43 patients). In 123 patients (33 positive results, 90 negative) therapeutic decisions were based solely on impedance test results. Examination required 20 to 30 minutres at a cost of $35. Follow-up ranging from 4 to 60 weeks failed to reveal documented thromboembolic complications or recurrence of lower extremity symptoms. In 37 patients (six positive results, 31 negative) impedance test results were ignored and inpatient workup, including invasive venography, was undertaken. Hospital charges for these patients averaged $1,500. In addition to its ease of performance and high degree of accuracy, comparison with inpatient evaluation documents its cost effectiveness. Impedance testing for emergency department evaluation of suspected deep vein thrombosis appears appropriate.

Cost effectiveness of clinical diagnosis, venography, and noninvasive testing in patients with symptomatic deep-vein thrombosis.

Until the past decade, physicians were content to base therapeutic decisions on the clinical diagnosis of deep-vein thrombosis. Subsequently, numerous studies demonstrated that clinical diagnosis of this condition is nonspecific. Although many now use objective methods to diagnose venous thrombosis, their relative cost and effectiveness have not been adequately studied. We performed a cost-effectiveness analysis of 516 patients with clinically suspected venous thrombosis who were evaluated by clinical diagnosis, venography, and the less invasive combination of impedance plethysmography and leg scanning. We used this analysis to rank these alternative approaches in terms of both cost and effectiveness. The results indicate that clinical diagnosis is cost ineffective. Venography is cost effective--more so when applied as an outpatient investigation. Impedance plethysmography plus leg scanning is a practical, less invasive alternative to outpatient venography. The cost of inpatient diagnosis is likely to remain the major cost; thus, emphasis should be placed on outpatient diagnostic procedures.