Rapid Responses to:
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Rapid Responses: Rapid Responses published:
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RAPID RESPONSE
- Santhi Adigopula (22 September 2004)
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D-Dimer testing to fight winter mortality!
- Friedrich Flachsbart (22 September 2004)
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DVT and D Dimer
- M Marimon (8 October 2004)
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Cover photo is not a DVT
- Paul E Jennings (9 October 2004)
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Re: DVT and D Dimer
- Friedrich Flachsbart (9 October 2004)
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DVT or calf haematoma?
- Feroz Dinah (10 October 2004)
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Goodnews for radiologists.
- LNRAO BONDUGULAPATI (10 October 2004)
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Clinical Judgement - and Ill-judged illustrations
- L S Lewis (11 October 2004)
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DVT or not DVT, that is the question
- Kamran Abbasi (12 October 2004)
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The choice of assay for D-dimer testing
- Justin Zaman (14 October 2004)
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Laboratory Diagnosis of DVT
- Seema Kalra (14 October 2004)
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What about post op DVT?
- M N Shah, N A Shah (15 October 2004)
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Pregnancy - A Cautionary Tale
- Sanjay C Patwardhan, Manasi S. Patwardhan (17 October 2004)
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D Dimer misleading in the presence of bruising
- James Tymms, Kate Pendry, Consultant Haematologist and Manju Bhavnani, Consultant Haematologist. (18 October 2004)
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Any suspicion of DVT requires simple basic actions.
- Martin F Brewster (19 October 2004)
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Diagnosis of Deep "Vein" Thrombosis
- Mark Moss (20 October 2004)
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Clotting Screen?
- Nicholas Collins (21 October 2004)
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Intravenous Drug Use: an important risk factor for DVT
- Daniel T Stephenson (1 November 2004)
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Don't forget the ruptured Baker's cyst
- Christopher R Holroyd, Richard Hull (12 November 2004)
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Incorrect data
- Roger EG Schutgens, Fred J.L.M. Haas, Douwe H. Biesma (19 November 2004)
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Santhi Adigopula, SHO in General Medicine NN!6 8UZ
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Deep vein thrombosis (DVT) and pulmonary embolism represent different manifestations of the same clinical entity. HOW ARE D-DIMERS FORMED: D-dimers are formed when plasmin degrades cross-linked fibrin. CONDITIONS WITH RAISED D-DIMERS: Elevated levels of D-dimers are found in nearly all patients with venous thromboembolic disease ,patients with active cardiopulmonary disease or malignancy and in those with recent surgery or trauma. This is the reason why an isolated positive D-dimer (greater than 0.2ug/ml) result is not useful because the test lacks specificity. VALUE OF THE TEST: D-dimer measurement is most useful in excluding a diagnosis of venous thromboembolic disease.A negative result using a sensitive D-dimer test is useful for excluding acute DVT and is more accurate when combined with Clinical Probabiltiy scores.I personally think this should be standardized in all hospitals. Santhi Adigopula. SHO Competing interests: None declared |
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Friedrich Flachsbart, General Medicine Praxis 37085 Göttingen
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Dear Sir, respiratory infections induce complement and coagulation cascades. The hypercoagulability leads to mortality. If You do serial tests of D-Dimer in patients with high risk, than risk-adapted anticoagulation with ASS or low-molecular-weight-heparin or even coumarin is possible. I do this in my praxis since 1996. Negative D-Dimer shows You: NO MORE RISK! NO MORE PROBLEM! Sincerily Yours Friedrich Flachsbart Competing interests: None declared |
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M Marimon, Consultant in acute medicine Worcestershire Royal Hospital WR5 1DD
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This article, supports the general approach throughout many acute departments, that a patient with low clinical probability for deep venous thrombosis (DVT) and normal D-Dimer testing, at least with moderate sensitivity, is enough to rule out the condition. This certainly should reduce the workload for imaging testing and may avoid referrals from secondary care, if D-dimer testing can be done in primary care. The difficult scenario, where more robust information is required, is how to approach a patient with high clinical probability, abnormal D-dimer testing with a normal doppler scan. ?rescanning and when?should be anticoagulated in the meantime or should we use compressive stockings or banadages, etc.. This is the area in which more clarification needs to be addressed. Competing interests: None declared |
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Paul E Jennings, consultant radiologist ipswich
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As radiologists we waste a lot of time unnecessarily scanning patients for ?DVT who on clinical grounds alone clearly have other conditions such as cellulitis, superficial thrombophlebitis or post traumatic haematoma. Whenever possible we try to educate our junior (and occasionally senior) clinical colleagues on the differences between these conditions. It was therefore very depressing to see a large picture on the cover of the BMJ, for a DVT article, showing pathology that is anything but that condition. It may show a traumatic bruise or superficial thrombophlebitis but DVT it ain't. In education pictures are just as important as text! Competing interests: None declared |
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Friedrich Flachsbart, General Medicine Praxis 37085 Göttingen
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Dear Sir, rescanning is useless (unless the patient becomes symptomatic). Serial D-Dimer testing is useful. Anticoagulation should be instituted at once, situation-adapted either ASS or LMW-Heparin/Coumarin. And then: Wait and look. Test D-Dimer again, look at the patient and decide what is good for him. (This approach was even right in little patients with cardiac malformation and open-heart-surgery. They developed postoperatively low grade intravascular coagulation with consequtive acute renal failure. Heparin stopped the downhill-cascades of organ-failure!) Sincerely Yours Friedrich Flachsbart Competing interests: None declared |
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Feroz Dinah, SpR Tr & Ortho St. George's Hospital, London
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History, examination and focused investigation is the backbone of diagnosis of any condition. The article does not mention any new information or algorithm for ruling out DVT. The real disappointment, however, is the cover picture: why did the BMJ use a picture of superficial bruising/calf haematoma to illustrate a DVT? Bruising is not even in the Wells clinical probability tool. Competing interests: None declared |
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LNRAO BONDUGULAPATI, House Officer - Medicine. Warwick Hospital,CV34 5BW.
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Dear collegues,do you know that "VIDAS D-Dimer Exclusion" is now cleared by the U.S. Food and Drug Administration (FDA) to exclude both pulmonary embolism (PE) and deep vein thrombosis (DVT). This clearance means that patients who present to the Emergency Department with suspected PE or DVT may no longer be subjected to invasive and costly imaging examinations for a negative diagnosis.A negative D- dimer assay result, provided by VIDAS D-Dimer Exclusion, enables clinicians to exclude a diagnosis of DVT and PE in less than an hour with no additional testing.Its a rapid, automated ELISA, having a negative predictive value (NPV) of greater that 99%. (Source - biomerieux-usa.com). So...,If it can be implemented worldwide,It will reduce the need for invasive and time-consuming examinations,reduces the burden on radiologists,reduces the period of stay in the hospital as well as the costs. Competing interests: None declared |
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L S Lewis, GP Surgery, Newport, Dyfed, SA42 0TJ
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This study concludes that 'combination of low clinical probability for deep vein thrombosis and a normal result from the SimpliRED D-dimer test safely excludes a diagnosis of acute venous thrombosis'. But the BMJ cover then illustrates the problem with a very bruised- looking Calf.. Haematoma, trauma, and the classic DVT-masquerader of Ruptured Baker's cyst are all more likely than a DVT here. A D-Dimer would almost certainly be positive in all such cases. Clinical Judgement remains paramount ! 'but does clinical judgement add anything to a negative D-Dimer test to enable EXCLUSION of DVT ? ' The real problem for clinicians is how to make the positive diagnosis, given the awareness that recent surgery, trauma, and other forms of activated clotting etc., will all yield to a positive D-dimer result, without there being a DVT. For DIAGNOSIS (INCLUSION) we will still need a DVT-specific test, such as only diagnostic immaging can provide, unless we are to Heparinise all those patients where we have reasonable clinical suspicion and/or a positive D-Dimer. Competing interests: None declared |
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Kamran Abbasi, Acting editor BMJ
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I am grateful to our respondents for questioning the diagnosis of the picture on this week's cover. The picture was chosen because it shows leg swelling and a diagnosis of DVT is far from certain, not because we thought it showed a DVT. A low clinical probability of DVT (plus D-dimer testing)is the focus of the paper. We can, of course, only tell so much from a picture, without the benefit of history and examination, and interestingly our picture source does describe this as a DVT. Competing interests: I am the acting editor of the BMJ and responsible for its content |
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Justin Zaman, specialist registrar in cardiology papworth hospital, cambridge, uk
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Thank you the reminder to clinicians of the importance of the clinical picture. You say that “Because the SimpliRED D-dimer assay had a much lower sensitivity (about 88%) and thus lower negative predictive value than the highly sensitive ELISA and immunoturbinometric tests, the use of this assay should be restricted to patients who have a low (less than or equal to 3%) probability of having deep vein thrombosis”. Consider the situation when D-dimer tests are applied to pulmonary embolus (PE) detection. The British Thoracic Society state that in clinical studies of PE, the SimpliRED test was used in 1177 patient with a test specificity of 68%. The overall negative predictive value (85%) was much higher (97%) in those with low clinical probability, and the combination of low clinical probability and negative SimpliRED D-dimer occurred in 44% of the cohort. The purpose of D-dimer testing is not to rule-in PE, because all the D-dimer tests have too low a specificity to rule-in PE. But this also depends on the pre-test probability of PE. The purpose of rule-out PE testing is not to "absolutely" exclude PE, which is impossible. We should use rule-out PE testing to decrease the posterior probability of PE to a figure below which further rule-out PE testing is not warranted (i.e. isotope perfusion or Computerised Tomography scan) From trials, patients with a normal lung scan had PE rates of ~ 4%. Virtually all PE diagnostic algorithms suggest that patients with a normal lung scan do not require further testing - even though they know from the data that 4% of PEs are going to be missed. Therefore, it is common practice to accept a missed-PE rate of ~ 4%. Consider the alternative rapid ELISA D-dimer test which has a sensitivity of 98% and a specificity of 43%.Using a Bayesian statistics program (as we are trying to calculate the posterior probability, plug in a sensitivity of .98 and a specificity of .43, and then keep on changing the prevalence figures until you get a negative predictive value of 96% (which is equivalent to accepting a false negative rate of 4% which we accepted above). The rapid ELISA test can only ensure that the false negative rate will be < 4% if the prevalence (pre-test probability of PE) is < 45%. One cannot use a very sensitive D-dimer test, such as the rapid ELISA D-dimer test, to r/o PE in moderate-high clinical probability patients (who have a prior probability of PE of > 45%). What about the SimpliRed D-dimer test? How well does it perform as a r/o-PE test. Using that Bayesian calculator and a sensitivity of 87% and a specificity of 65% the SimpliRed test would only produce a posterior probability of PE < 4% if the prevalence (prior probability of PE) is < 15%. In other words, the SimpliRed D-dimer test does not seem to be as good as the rapid ELISA test. But, is that true? Well, the "average" figure of a PE in a low clinical probability patient is ~ 8%. Presume that we accept those figures, then you can see that a figure of 8% (as opposed to less than 3% in your study on DVT) is well below the SimpliRed D-dimer test's threshold of 15%. That means that a SimpliRed D-dimer test is as good as the rapid ELISA D-dimer test in excluding PE in low clinical probability patients. Competing interests: None declared |
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Seema Kalra, SHO General Medicine Morriston Hospital, Swansea, SA6 6NL
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I congratulate the authors and the BMJ editorial team for publishing such an important and useful topic. As junior doctors, we face this dilemma of diagnosis of DVT everyday. We recently did an audit in the Haematology department of Morriston Hospital comparing two different d-dimer assay methods. The results showed that SimpliRed d-Dimer assay has lower sensitivity of about 75% and a negative predictive value of 78.9% as compared to D-Dimer Plus ELISA which has sensitivity of about 93% and negative predictive value of about 90%. The Department of Hematology at Swansea NHS Trust is now conducting a prospective case controlled study of 200 patients presenting with possible DVT to compare the suitability and negative predictive values of four different d-Dimer assays(Dade-Behring D-Dimer Plus, Biopool Auto-Dimer, Biopool Mini-Quant D-Dimer and SimpiRed) Hopefully this will give us some help in striking a good balance between sensitivity and specificity in our setup. Sincerely S Kalra Competing interests: None declared |
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M N Shah, spr obs and gynae Wigan WA12NN, N A Shah
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A very interesting article. However we often deal with post operative DVT in our surgical practice after major gynaecological or orthopaedic surgical procedures. Is it possible to shed light on the actual status of D dimer testing in relation to its sensitivity and specificity on detecting DVT after major surgery, and especially the temporal duration, after or before which it may be considerd reasonably accurate? Thank you. Competing interests: None declared |
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Sanjay C Patwardhan, Specialist Registrar Dept of Obs & Gyn, Worcestershire Royal Hospital, Newtown Road, Worcester WR5 1DD, Manasi S. Patwardhan
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Venous Thrombo-Embolism (VTE) still remains the leading Direct cause of maternal deaths in United Kingdom as per Confidential Enquiry in to Maternal Deaths (1997-1999) and the same report also emphasise “ Failure to Diagnose” being responsible for 40% (3/8) deaths1. The clinical diagnosis of venous thrombosis in pregnancy can be challenging because (1) unilateral left leg swelling can be caused by compression of the left iliac vein by the gravid uterus, (2) leg swelling can be caused by isolated common iliac vein thrombosis that may not be detectable by compression ultrasonography, and (3) Presence of extensive varicosities2. Furthermore in pregnancy, D-dimer can be elevated due to the physiological changes in the coagulation system and particularly if there are concomitant problems such as pre-eclampsia, multiple gestation, diabetes in pregnancy etc. Thus a 'Raised' D-dimer test in pregnancy is not necessarily consistent with VTE3.In a prospective cohort study of 61 patients from Austria, D-Dimer levels were shown to be significantly increased among patients and controls during pregnancy4. Due to these dilemmas physician vigilance for this disease should remain high. The diagnosis of deep vein thrombosis (DVT) in the pregnant patient requires the use of optimal objective imaging5. However in cases of dilemma treatment with heparins should be commenced1. References: 1. Why Mothers Die 1997-1999 – The Confidential Enquiries into Maternal Deaths in the United Kingdom 2. Hirsh J, Lee A et al. How we diagnose and treat deep vein thrombosis, Blood 2002; 99:3102-3110 3. Royal College of Obstetricians & Gynaecologists. Thromboembolic Diseases in Pregnancy and the Puerperium: Acute Management. Guideline No:28 London: RCOG; 2001 4. Hoke M, Kyrle P, Phillip K et al. Prospective evaluation of coagulation activation in pregnant women receiving low-molecular weight heparin. Thrombosis and Haemostasis 2004; 91: 935-940 5. Chan W, Ginsberg JS. Diagnosis of deep vein thrombosis and pulmonary embolism in pregnancy. Thrombosis Research 2002; 107(3-4):85-91 Competing interests: None declared |
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James Tymms, Consultant Physician Royal Albert Edward Infirmary. Wigan. WN1 2NN, Kate Pendry, Consultant Haematologist and Manju Bhavnani, Consultant Haematologist.
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Sir, We endorse Fancher et al conclusions that a normal D-dimer result safely rules out a DVT in a patient with a low probability pre-test score. We have been using this strategy successfully and safely for outpatient care in Wigan for 4 years. The front cover shows a patient with extensive bruising which suggests an alternative diagnosis. In this situation the D-dimer will be elevated due to the clotting process. However, if this interpretation is not appreciated, the patient may be given heparin in the erroneous belief that pain and swelling with an elevated D-dimer indicates a possible DVT. The photograph may encourage this view. If there has been trauma, or a Baker’s cyst, heparin therapy is likely to be harmful by causing bleeding. We have seen similar scenarios in patients with chest pain with a raised D-dimer who were given heparin. One patient had a dissecting aneurysm and another a splenic haematoma, from undisclosed trauma two weeks previously, which ruptured. We have therefore restricted its use for PE. An elevated D-dimer occurs in many conditions, including haemorrhage, and it therefore essential that the D-dimer test is understood to be a test of exclusion and NOT INCLUSION. The front cover photograph is very unfortunate as it undermines the importance of this essential point. Competing interests: None declared |
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Martin F Brewster, Retired GP Wigtown DG8 9DZ
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Any suspicion of DVT requires simple basic actions.
Deep venous thrombosis (DVT) risks sudden death. All clinicians must keep in mind that negative clinical or laboratory examinations (such as D-dimer) for DVT will NOT and can NOT exclude the onset of a DVT hours or days after the test.
Just this possibility alone obligates immediate action to inhibit clot spread and embolic incidents. Such hazard requires constant re-emphasis in the teaching of postgraduates, junior doctors, medical students and ancillaries.
No matter whether DVT tests are negative, positive, or pending, (and even if other treatments are in hand), all suspected DVT cases need immediate: -
1. bed foot elevation, when in bed,
2. effective venous compression, especially when ambulant by day, and, (some would say), 3. low dose aspirin and/or nonsteroidal anti-inflammatory drug treatment, pending test results and institution of more specific treatment when indicated.
Presentations may include calf muscle tear, kicks from cattle, sports injuries, cellulitis, ruptures of Baker's cyst, tears after prolonged cramp, "pill" taking, distance travel, ankle/leg oedema in patients recently discharged from hospital (even when expected, e.g. after hip replacements), and so on, but in "?DVT versus accurate differential diagnosis" situations, simple DVT containment action is the urgent first priority.
1. Bed foot elevation of 1½ - 2 inches keeps lower leg veins collapsed, being above heart intake level. Few patients experience any head-down effects at this elevation. Most head pillow positions are higher than the bedfoot elevation. The effect on most oedema is magical!
For patients outside hospital, exact, and preferably written, elevation instructions must emphasise that the whole bed be angled and that leg pillows are dangerous. Six leg beds can have half height support for the middle legs.
2. Any elastic hosiery or elastic tubular bandage (Tubigrip) may be adequate for compression needs, but best of all is a specific anti-embolism stocking, such as Kendall T.E.D.. Application should avoid "milking".
Bandages do not give overall even support. By stretching within hours, the commonly used crepe bandage becomes hopelessly ineffective. Daytime leg compression support should continue for at least three weeks, and bed elevation for at least six weeks - or until limb thickening and/or ankle oedema have disappeared. Furthermore, long term continuation of these basic measures in proven DVT situations reduces the incidence of chronic ankle oedema and permanent "thick leg". Lastly, it is pertinent that a Scottish newspaper has recently highlighted the potential tragedy lurking in negative DVT investigations. ¹ Headlines read: -
Investigation into DVT death reveals case of 'bad luck' and The student who predicted she would die. ,
I quote the following from two long reports: -
"For almost a week, Katie McPherson, a 23-year-old student, had told doctors she had the classic symptoms of deep vein thrombosis (DVT). On the three occasions she had seen doctors, .... . ....had learned about DVT on her occupational therapy course. ....was a victim of the differences in methods and approaches taken by NHS hospitals in diagnosing and treating DVT. The parents of a student who died from deep vein thrombosis (DVT) have been told by doctors that even a good clinician has only a 50 per cent chance of detecting the condition. .... were told the most common method for identifying the condition is flawed and is being replaced with a system that is potentially even less reliable." The reports suggest that, despite her premonitions, correct self-diagnosis, and her having two or more known risk factors, this unfortunate girl and her medical advisors relied on her three almost negative assessments. The only treatment or advice mentioned is a crepe bandage. In view of the fatality, one might guess also that she had no night bed elevation, that she was not taking aspirin, and that also her ancillary medical course had not provided information on the simple management of DVT, (in not covering basic measures which doctors might reasonably ask their occupational therapists to arrange). There is an urgent NHS need for a mandatory (hospital, GP, and ancillary) advisory protocol covering the simple basic measures required to reduce embolic deaths.
(1)
The Scotsman 19 Aug 2004 and 11 Oct 2004
Competing interests: None declared |
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Mark Moss, Consultant Radiologist B18 7QH
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Dear Sir It is with considerable despair that I assimilate the front cover of the 9th October 2004 edition of the BMJ. Above the title of one of the papers on the diagnosis of deep venous thrombosis (DVT) is a picture of a patient’s lower leg. The fine linear impressions on the skin of the calf indicate that this patient had been wearing a thrombo-embolic deterrent stocking until shortly before the picture was taken. The inference is that this calf shows the typical appearances of a DVT. In fact there is yellowish-black discoloration of the skin of the back of the calf extending from the popliteal fossa which is, of course, a bruise. Bruising is not a feature of deep venous thrombosis, although occasionally it is seen in superficial venous thrombosis. As one who, amongst many, has scanned countless legs where even cursory clinical assessment would have discounted the possibility of DVT it is with a renewed feeling of futility that I look towards my next ultrasound list. Assuming the patient is not post-operative then the most likely explanation for the appearance of the calf would be a ruptured medial head of gastrocnemius or, as occasionally pitches up in the indiscriminate pile of Doppler requests, a ruptured popliteal aneurysm. Good quality medical education should produce doctors who are capable of obtaining succinct and accurate histories and performing appropriate examinations. History and examination form a very cost-effective basis for further investigation. If this initial process is ignored it initiates a chain of disjointed, ill -considered investigations, with their concomitant costs, that immediately offsets any clever application of (nurse-led?) investigative protocols. Competing interests: None declared |
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Nicholas Collins, Staff Specialist Ambulatory Care Macarthur Health Service
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Clotting screen? Dear Sir, We read with interest the work of Fancher et al. on the combined use of rapid D-dimer testing and estimation of clinical probability in the diagnosis of deep venous thrombosis (DVT) (1). We are enthusiastic about the implications of this work for the diagnosis of DVT in an outpatient setting, as it may allow an economical, safe and prompt exclusion of the diagnosis in low risk patients. When used in combination with clinical assessment, a rapid D-dimer test may be a simpler clinical pathway that reduces the need for Doppler ultrasound. It has been established that of the available options, use of rapid D-dimer and clinical assessment in combination with a single ultrasound is highly cost-effective, more so than the use of serial ultrasonography (2). Yet even a single use of venous ultrasound imaging may not be readily available in areas with limited resources, and unnecessary use of the tool imposes a significant burden on the community, in terms of cost and accessibility of ultrasonography. SimpliRED D-dimer tests are already widely available; hence using them to refine clinical assessment will allow maximal utilisation of existing resources. As to the clinical application of the assessment combination proposed by Fancher et al., we are unsure how specific this is as a test for exclusion of DVT in the general population. It is well recognized that the D-dimer level may increase with myocardial infarction, recent surgery, trauma or any systemic illness (3). A patient presenting with symptoms and signs suspicious of DVT may well have underlying pathology causing a high D-dimer. It would be fair to question the practical usefulness and significance of such a test if a high proportion of patients have an elevated D-dimer. The paper did not specify the proportion of patients included in this review with a high D-dimer assay, making judgment on this issue difficult. Furthermore, in a clinical setting where different practitioner approaches interplay with patient factors and an increasingly litigious environment, it is difficult to determine whether the added subjective benefits of a venous ultrasound would incline practitioners to order the investigation despite the review findings. As the authors pointed out, these findings may not be applicable once the new Wells probability tool classification scheme is adopted. Therefore, despite the development of novel combined clinical classifications and laboratory approaches to diagnosis, it is important to emphasise the necessity of traditional clinical acumen in determining the pre-test probability that the patient has a condition before potentially unnecessary testing is undertaken (4). In conclusion, this systematic review highlights the potential of an economical, accessible and rapid D-dimer test to exclude DVT in low risk patients. The findings are promising for use in the field of outpatient care. They are particularly relevant for health services with limited resources and those without ready access to pathology services or where there are geographical considerations in referring patients. There is also a potential for use in the long-term observation settings of ambulatory care and general practice follow-up. Sincerely, Kate Crossley and Kenny Sze
Competing interests: None declared |
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Daniel T Stephenson, Locum Consultant in Emergency Medicine Rotherham General Hospital, Moorgate Road, Rotherham, South Yorkshire S60 2UD
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The Well's criteria quoted in Fancher et al's review have been used widely in assessing the clinical probability of DVT. However, I believe that there is an important omission from the listed risk factors: intravenous drug use (IDU), particularly involving groin injection. There is little evidence on this subject. However, a study of women with DVT in Glasgow found that 21.4% of 322 consecutive cases of confirmed DVT were associated with IDU (1). This figure rose to 52.4% in women under 40 years. Anecdotally, several years experience of using Well's criteria at the Northern General Hospital in Sheffield would confirm IDU as a commonly encountered factor conferring a significant risk of DVT. Until more detailed evidence is available, I believe the only safe practice is for clinicians to place all patients who are intravenous drug users in the high risk category, and investigate accordingly. I understand the reason that IDU is not included in Well's criteria is due to the very low prevalence of IDU in his study population. This highlights the risk of implementing the findings of research in populations which differ from the study population in terms of disease prevalence and aetiology. References 1 McColl MD, Tait RC, Greer IA et al Injecting drug use is a risk factor for deep vein thrombosis in women in Glasgow. Br J Haematol 2001;112(3):641-3. Competing interests: None declared |
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Christopher R Holroyd, SpR Rheumatology Queen Alexandra Hospital, Portsmouth, PO6 3LY, Richard Hull
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Editor - The cover of the issue of 9 October shows a leg with bruising behind the knee, extending to the mid calf and down the ankle. The image is used to illustrate a below knee deep vein thrombosis. The accompanying paper concludes that deep vein thrombosis can be effectively excluded in suspected patients if the clinical probability is judged to be low or moderate, and a D-Dimer test is negative. Ultrasound testing in such cases is unnecessary1. The amount of bruising shown in the picture is far in excess of that seen commonly in deep vein thrombosis. The classical picture of a ruptured Baker’s cyst is that of swelling behind the knee tracking down the calf, sometimes with bruising at the ankle. However presentation similar to that shown is not uncommon. It is therefore important to highlight this in the differential diagnosis. Clinical examination is not always helpful. If this paper’s suggestions are followed, a negative D-Dimer would preclude ultrasound scanning in many cases. Ruptured Baker’s cysts are a significant cause of pain and disability, which can be helped by prompt treatment. It is recognised that Baker’s cysts do not necessarily need a background of pre-existing disease to occur and may occur in normal knee joints2. They can, and do co-exist with a deep vein thrombosis There is significant morbidity associated with Baker’s cyst rupture and so it is important to consider this as a potential diagnosis in patients with calf or knee pain, even though a D-Dimer may well be negative. Ultrasound scanning is extremely useful in diagnosis. Chris Holroyd, Specialist Registrar,
1. Fancher TL, White RH, Kravitz RL; Combined use of rapid D-dimer testing and estimation of clinical probability in the diagnosis of deep vein thrombosis: systemic review. BMJ 2004; 329:821-824 2. Macfarlane DG, Bacon PA; Popliteal cyst rupture in normal knee joints. BMJ 1980; 281:1203-1204 Competing interests: None declared |
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Roger EG Schutgens, haematologist University Medical Center Utrecht, The Netherlands, Fred J.L.M. Haas, Douwe H. Biesma
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Dear sir, In the paper by Fancher et al (1), the authors present a review on the diagnostic management in patients suspected for having deep vein thrombosis. We have two remarks on this systematic review. First, the authors make a clear distinction between accuracy and management studies. They state that there was one management study (2) that used a D-dimer assay alone as the initial test. However, reading the results section of that study, it is clear that all patients underwent an ultrasound for safety reasons. Second, in table 3 the authors present six management studies. We do not understand why data on age and sex are stated as unknown in our study (3), as these data are clearly described in the results section. Furthermore, the authors claim that there were 15 patients lost to follow up in our study. This is incorrect, as only 1 patient was lost to follow up. Again, this was also clearly stated in the first paragraph of the results section. We regret that this table might have a negative influence on the interpretation of the results of our study. We contacted the authors and requested a correction of this table, which has been published in the current issue of the BMJ. REG Schutgens, FJLM Haas and DH Biesma Correspondence: Roger E.G. Schutgens, MD, PhD Department of Hematology University Medical Centre Heidelberglaan 100 3584 CX Utrecht tel: +31.30.2509111 fax: +31.30.2511893 E-mail: r.schutgens@azu.nl References 1. Fancher TL, White RH, Kravitz RL. Combined use of rapid D-dimer testing and estimation of clinical probability in the diagnosis of deep vein thrombosis: systematic review. BMJ 2004;329:821. 2. Perrier A, Desmarais S, Miron MJ, de Moerloose P, Lepage R, Slosman D, Didier D, Unger PF, Patenaude JV, Bounameaux H. Non-invasive diagnosis of venous thromboembolism in outpatients. Lancet 1999;353:190-5. 3. Schutgens RE, Ackermark P, Haas FJ, Nieuwenhuis HK, Peltenburg HG, Pijlman AH, Pruijm M, Oltmans R, Kelder JC, Biesma DH. Combination of a normal D-dimer concentration and a non-high pretest clinical probability score is a safe strategy to exclude deep venous thrombosis. Circulation 2003;107:593-7. Competing interests: None declared |
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