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![[Read Comment]](/icons/misc/sectionDOWN.gif){kind=icon}
Response to Drs. Hull and Stagnaro regarding Diagnosis and Management of Venous Thromboembolism Systematic Review
Bedside Biophysical-Semeiotic Diagnosis of deep Vein Thrombosis, since very early stage
Further Advances in the Diagnosis of Venous Thromboembolism
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Jodi B Segal, Baltimore Assistant Professor of Medicine, Johns Hopkins University School of Medicine, John Eng, Eric B Bass
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We are grateful for the comments of Dr. Hull who has identified other papers relevant to this topic. In our review, we cite the results from the PIOPED II study although we could not formally include it in our systematic review because we restricted our review to studies which compared helical CT to pulmonary arteriography.(1) Nonetheless, we agree that it is a highly relevant study. Somewhat surprisingly, the sensitivities and specificities reported in PIOPED II are similar to those reported in the earlier papers we cite despite the use of more advanced technology. Similarly, the study by Perrier in NEJM(2) and the study by the Christopher Investigators published in JAMA(3) were not eligible for inclusion in our review because not all enrolled patients had arteriography. We consider these studies to be evaluations of diagnostic strategies rather than strictly evaluations of the technology of helical CT. Resources did not allow us to review all of the relevant diagnostic strategies which have been tested. We think that understanding the test characteristics of helical CT, in isolation, are important before its place in diagnostic test strategies can be established. We want to reiterate that there is only level 2 evidence regarding the use of helical CT, in isolation, for diagnosis of PE. We agree, entirely, that clarification of the role of CT in diagnostic strategies is essential and that the evidence for its use may already be strong. The two articles cited by Dr. Hull regarding high-quality trials comparing LMWH to warfarin for three-month treatment of VTE would have been included in our review of the management of VTE had they been available during preparation of this review and guidelines.(4;5)These articles were published within the last two months, and provide further support for the guideline recommendations. We appreciate the comments of Dr. Stagnaro. We agree that additional physical examination signs that assist with the diagnosis of venous thromboembolism may be useful additions to the existing clinical prediction rules. As these are identified, they should be rigorously tested and their place in clinical prediction rules evaluated. Reference List (1) Stein PD, Fowler SE, Goodman LR, Gottschalk A, Hales CA, Hull RD et al. Multidetector computed tomography for acute pulmonary embolism. N Engl J Med. 2006;354:2317-27. (2) Perrier A, Roy PM, Sanchez O, Le Gal G, Meyer G, Gourdier AL et al. Multidetector-row computed tomography in suspected pulmonary embolism. N Engl J Med. 2005;352:1760-1768. (3) van BA, Buller HR, Huisman MV, Huisman PM, Kaasjager K, Kamphuisen PW et al. Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. JAMA. 2006;295:172-79. (4) Hull RD, Pineo GF, Brant RF, Mah AF, Burke N, Dear R et al. Self -managed long-term low-molecular-weight heparin therapy: the balance of benefits and harms. Am J Med. 2007;120:72-82. (5) Hull RD, Pineo GF, Brant RF, Mah AF, Burke N, Dear R et al. Long -term low-molecular-weight heparin versus usual care in proximal-vein thrombosis patients with cancer. Am J Med. 2006;119:1062-72. Competing interests: None declared |
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Sergio Stagnaro, MD, Genova, Italy Founder of Biophysical Semeiotics, Biophysical Semeiotics Research Laboratory
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All general practitioners, all around the world, know exactly that patients with acute deep vein thrombosis could undergo home therapy with heparin for at least five days followed by long term oral anticoagulation, as standard care for such patients, under some well-known circumstances. This procedure is possible nowadays due to the emergence of low molecular weight heparin, which recently proved to be a safe, effective, and convenient treatment for deep vein thrombosis that really “challenged the need for routine admission”. As a matter of facts, it is generally admitted that low molecular weight heparin is at least as effective and safe as unfractionated heparin for the initial treatment of deep vein thrombosis, according to the results of a lot of randomised trials. For instance, a lot of papers add to the evidence as regards home treatment of deep vein thrombosis (1). However, according to all authors, such as aim can be achieved on condition that an accurate evaluation of the patients would allow doctor to perform an optimal selection of patients for home treatment. In other words, a general practitioner must have an accurate patient’s history (e.g., history of recurrent venous thromboembolism), recognize at the bed-side pulmonary embolisms, identify coexisting conditions requiring hospitalisation, such a latent heart insufficiency, and so on. Interestingly, in individual, in supine position, involved by “initial” deep vein without clinical symptomatology, digital pressure upon phemoral vein at the groin brings about gastric aspecific reflex (= in the stomach, both body and fundus dilate, while antral-pyloric region contracts. See www.semeiotcabiofisica.it in Technical Page 1), after a pathological latency time less than normal 8 sec., lasting more than physiological 3 sec.. These parameter value of reflex are inversely and respectively directly related to the severity of underlying vein disorder (7, 8). In my opinion, doctors need urgently at the bed side an effective physical semeiotics that enables them to recognize promptly and reliably all these pathological situations, really difficult to identify with the aid of the old, traditional semeiotics (See: my rapid response in bmj.com.: A new physical semeiotics in detecting disorders otherwise undiagnosed, 30 March, 2001 and http://www.semeioticabiofisica.it). This currrent lack of a clinical tool, useful in bed-side diagnosis, accounts for the reason that even among patients with deep vein thrombosis, randomised to home treatment, up to half were initially admitted to hospital, and for the reluctance of some centres to consider home treatment, despite its favourable influence on NHS expenses. Finally, a lot of authors show clearly that Evidence Based Medicine is a scientific, reductionist approach, representing the reality of groups, valid in context but with limitations. On the contrary, Single Patient Based Medicine is a scientific, holistic approach, representing the reality of groups and individuals, validating evidence in context (4- 8). 1) Schwarz T, Schmidt B, Hohlein U, Beyer J, Schroder H-E, Schellong SM. Eligibility for home treatment of deep vein thrombosis: prospective study. BMJ 2001; 322: 1212-1213. 2) Koopman MMW, Prandoni P, Piovella F, Ockelford PA, Brandjes DPM, van der Meer J, et al. Treatment of deep vein thrombosis with intravenous unfractionated heparin administered in the hospital as compared with subcutaneous low-molecular-weight heparin administered at home. N Engl J Med 1996; 334: 682-687. 3)Levine M, Gent M, Hirsh J, Leclerc J, Anderson D, Weitz J, et al. A comparison of low-molecular-weight heparin administered primarily at home with unfractionated heparin administered in the hospital for proximal deep -vein thrombosis. N Engl J Med 1996; 334: 677-681. 4) Stagnaro S., Stagnaro-Neri M. Single Patient Based Medicine.La Medicina Basata sul Singolo Paziente: Nuove Indicazioni della Melatonina. Ed. Travel Factory, Roma, 2005. http://www.travelfactory.it/ 5) Stagnaro S., Stagnaro-Neri M., Le Costituzioni Semeiotico- Biofisiche.Strumento clinico fondamentale per la prevenzione primaria e la definizione della Single Patient Based Medicine. Travel Factory, Roma, 2004. http://www.travelfactory.it/ 6) Stagnaro Sergio. Single Patient Based Medicine: its paramount role in Future Medicine. Public Library of Science. 2005. http://medicine.plosjournals.org/perlserv/?request=read-response. 7) Stagnaro-Neri M., Stagnaro S., Flebopatie Ipotoniche Istangiopatiche. Min Angiol. 19, 57, 1994 8) Stagnaro-Neri M., Stagnaro S., Il diagramma venoso nelle arteriopatie obliteranti periferiche. Atti Congr. Naz. Soc. It. Flebologia Clinica e Sperimentale. Firenze 10-12 Dicembre 1990. A cura di G. Nuzzaci, pg. 169, Monduzzi Ed. Bologna. Competing interests: None declared |
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Russell D. Hull, Calgary, Canada Professor of Medicine, University of Calgary
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The clinical practice guidelines reported in the Annals of Family Medicine (1, 2, 3) articulate practical clinical recommendations. Recent publications provide additional information which either strengthens or modifies the suggested clinical guidelines. 1. Spiral computed tomography. The findings of recent level 1 studies which are not available in the guideline report mandate a revision for the practice guidelines for the diagnosis of pulmonary embolism. These level 1 studies provide a critical link for clinical practice guidelines for the use of helical (spiral) CT of the chest and lower extremity. In brief, the clinical practice guideline authors concluded from the citations included in their report that the evidence for the use of helical CT (multidetector CT) is level 2. This conclusion can now be altered to level 1 on the basis of three very large rigorous studies published in 2005 and 2006 which further elicidate the role of multidetector CT.(4, 5, 6) In addition, important information concerning the role of computed tomographic venography is now cited.(6) Perrier et al (4) report the findings of a large outcome study. They conclude that “our data indicate the potential clinical use of a diagnostic strategy for ruling out pulmonary embolism on the basis of D- dimer testing and multidetector-row CT without lower limb ultrasonography. A larger outcome study is needed before this approach can be adopted.” The findings by Perrier et al are supported by the findings of the Christopher Study,(5) also a large outcome study. The authors of the Christopher Study conclude appropriately “A diagnostic management strategy using a simple clinical decision rule, D-dimer testing, and CT is effective in the evaluation and management of patients with clinically suspected pulmonary embolism. Its use is associated with low risk for subsequent fatal and nonfatal VTE.” Further critical evidence for the use of the spiral CT is reported by Stein et al,(6) who report the findings of PIOPED II, a large accuracy study evaluating spiral CT and computed tomographic venography (CTV). The results of PIOPED II demonstrate that “In patients with suspected pulmonary embolism, multidetector CTA–CTV has a higher diagnostic sensitivity than does CTA alone, with similar specificity. The predictive value of either CTA or CTA–CTV is high with a concordant clinical assessment, but additional testing is necessary when the clinical probability is inconsistent with the imaging results.” Finally, based on these aggregate data, “The PIOPED II investigators (7) recommend stratification of all patients with suspected pulmonary embolism according to an objective clinical probability assessment. D- dimer should be measured by the quantitative rapid enzyme-linked immunosorbent assay (ELISA), and the combination of a negative D-dimer with a low or moderate clinical probability can safely exclude pulmonary embolism in many patients. If pulmonary embolism is not excluded, contrast -enhanced computed tomographic pulmonary angiography (CT angiography) in combination with venous phase imaging (CT venography), is recommended by most PIOPED II investigators, although CT angiography plus clinical assessment is an option. In pregnant women, ventilation/perfusion scans are recommended by many as the first imaging test following D-dimer and perhaps venous ultrasound. In patients with discordant findings of clinical assessment and CT angiograms or CT angiogram/CT venogram, further evaluation may be necessary. The sequence for diagnostic test in patients with suspected pulmonary embolism depends on the clinical circumstances.” It is evident from these new findings that the practice guidelines for the use of spiral CT for the Annals of Family Medicine should be revised. Finally, Roy et al (8) report the findings of a key study showing the importance of adhering to guidelines for the diagnosis of pulmonary embolism. Failure to adhere to guidelines is harmful in patients with suspected pulmonary embolism. 2. LMWH use instead of vitamin-k-antagonists The authors recommendations for this practice guideline are strengthened by the finding of two recent randomized trials (9, 10) which support the practice guideline authors’ conclusions. Hull et al performed a randomized, multicentre study comparing long-term therapeutic low- molecular-weight heparin subcutaneously once daily with long-term vitamin- K-antagonist therapy for 3 months in a broad spectrum of patients and in patients with cancer. Hull and colleagues concluded “that LMWH is similar in effectiveness to the usual-care vitamin-K-antagonist treatment for preventing recurrent venous thromboembolism in a broad spectrum of patients. It causes less harm and enhances the clinicians’ therapeutic options for patients with proximal deep vein thrombosis. Our findings reported here suggest the possibility of a broader role for long-term LMWH in selected patients.” The findings in patients with cancer “confirm the limited but benchmark data in the literature that long-term low-molecular- weight heparin is more effective than vitamin-K-antagonist therapy for preventing recurrent venous thromboembolism in patients with cancer and proximal venous thrombosis.” References: 1. Segal JB, Eng J, Tamariz LJ, Bass EB. Review of the Evidence on Diagnosis of Deep Venous Thrombosis and Pulmonary Embolism. Ann Fam Med 2007; 5: 63-73. 2. Snow V, Qaseem A, Hornbake ER, et al. Management of Venous Thromboembolism: A Clinical Practice Guideline from the American College of Physicians and the American Academy of Family Physicians. Ann Fam Med 2007; 5: 74-80. 3. Qaseem A, Snow V, Barry P, et al. Current Diagnosis of Venous Thromboembolism in Primary Care: A Clinical Practice Guideline from the American Academy of Family Physicians and the American College of Physicians. Ann Fam Med 2007; 5: 57-62. 4. Perrier A, Roy P-M, Sanchez O, et al. Multidetector-Row Computed Tomography in Suspected Pulmonary Embolism. N Engl J Med 2005;352:1760-8. 5. Writing Group for the Christopher Study Investigators. Effectiveness of Managing Suspected Pulmonary Embolism Using an Algorithm Combining Clinical Probability, D-Dimer Testing, and Computed Tomography. JAMA. 2006;295:172-179. 6. Stein PD, Fowler SE, Goodman LR, et al, for the PIOPED II Investigators. Multidetector Computed Tomography for Acute Pulmonary Embolism. N Engl J Med 2006;354:2317-27. 7. Stein PD, Woodard PK, Weg JG, et al. Diagnostic Pathways in Acute Pulmonary Embolism: Recommendations of The PIOPED II Investigators. Am J Med 2006; 119, 1048-1055. 8. Roy P-M, Meyer G, Vielle B, et al for the EMDEPU Study Group. Appropriateness of Diagnostic Management and Outcomes of Suspected Pulmonary Embolism. Ann Intern Med 2006; 144: 157-164. 9. Hull RD, Pineo GF, Brant RF, et al for the LITE Trial Investigators. Long-term Low-Molecular-Weight Heparin versus Usual Care in Proximal-Vein Thrombosis Patients with Cancer. Am J Med 2006 119, 1062 -1072. 10. Hull RD, Pineo GF, Brant RF, et al for the LITE Trial Investigators. Self-Managed Long-Term Low-Molecular-Weight Heparin Therapy: The Balance of Benefits and Harms. Am J Med 2007 120, 72-82. Competing interests: None declared |
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