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Year : 2023  |  Volume : 6  |  Issue : 1  |  Page : 1-5

The point on calf vein thrombosis

Vascular Centre, Nuova Villa Claudia, Rome, Italy

Date of Submission14-Jan-2023
Date of Decision31-Jan-2023
Date of Acceptance01-Feb-2023
Date of Web Publication26-May-2023

Correspondence Address:
Prof. Pier Luigi Antignani
Vascular Centre, Nuova Villa Claudia, Rome
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2589-9686.377614

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How to cite this article:
Antignani PL. The point on calf vein thrombosis. Vasc Invest Ther 2023;6:1-5

How to cite this URL:
Antignani PL. The point on calf vein thrombosis. Vasc Invest Ther [serial online] 2023 [cited 2023 Jun 8];6:1-5. Available from: https://www.vitonline.org/text.asp?2023/6/1/1/377614

Distal deep vein thromboses are a frequent event, approaching half of all cases of deep vein thrombosis (DVT) diagnosed by whole-leg ultrasonography. Despite the common occurrence, their optimal management is still a matter of debate, many of the concerns arising from inadequate knowledge of natural history and clinical relevance. Indeed, diagnostic and therapeutic approaches vary greatly among clinicians and institutions.

Careful surveillance is suggested for subjects with intracranial bleeding, in that we observed a significant increased risk of propagation. The therapeutic approach to isolated distal deep vein thrombosis (IDDVT) was markedly heterogeneous, highlighting the need for vascular medicine experts taking charge of venous thromboembolism (VTE). The authors suggest a benefit of standard anticoagulant treatment in decreasing propagation and all-causes death, but further studies focused on this critical topic are urgently needed.

Calf vein thrombosis was defined as any clot involving the deep veins of the calf that did not extend into the popliteal vein. The calf veins are three paired veins, posterior tibial, fibular, and anterior tibial and two nonpaired muscular veins, soleal, and gastrocnemial.[1] Usually, the most common veins involved are the peroneal veins. The following terms should be used in clinical practice to identify thrombosis of the calf according to the nomenclature: Isolated calf muscle vein thrombosis (ICMVT) for a thrombosis confined to the muscle veins only; deep calf vein thrombosis (DCVT) for a thrombosis present in the paired calf veins; isolated distal calf vein thrombosis (IDDVT) for the composite of ICMVT and DCVT, occurring either in isolation or in combination.[2]

The confluent segment that joins axial veins to the popliteal vein, called “trifurcation area,” is often considered proximal.

Anterior tibial vein thromboses are uncommon, so these veins are generally excluded from ultrasound investigation.

The prevalence of the disease is between 5% and 33% of all DVT cases detected by ultrasound:[3] Low in symptomatic patients and higher in asymptomatic patients at high risk of DVT: 15% after knee or hip surgery and 45% after coronary artery bypass surgery.[4]

In 2007, a study from Nord-Trøndelag, Norway, which was based on all residents ≥20 years (n = 94 194), identified the incidence of VTE between 1995 and 2001 from diagnosis characteristics retrieved from medical records.[5] A total of 740 patients with a first-time VTE event were identified (incidence rate, 1.43/1000 person-years), with a DVT incidence rate of 0.93/1000 person-years. Proximal DVT (PDVT) was 3-fold more frequent than distal DVT, and it was mostly located on the left side. The incidence increased exponentially with age and it was higher in cancer patients.

A new, retrospective, single-center study on ultrasound-verified DVT has illustrated the large diversity of thrombus distribution. The analysis concerned patients >18 years old presenting with unilateral DVT who were referred to one hospital in Antwerp between 1994 and 2012 (n = 1338).[6],[7] Calf vein DVT (distal DVT) occurred in 28% of the cohort, femoropopliteal DVT in 33%, and iliofemoral DVT (PDVT) in 38%.

Calf thrombosis can be asymptomatic or symptomatic: thrombi in the first case are smaller and with fewer complications. Seinturier et al.[8] have studied 1913 patients with vein thrombosis of the lower limbs for 2 years: they found that at 2 years, the survival rate was 80% in patients with unilateral distal thrombosis, 67% in bilateral distal, 72% in unilateral proximal, and 65% in bilateral proximal thrombosis. Thromboembolic disease was present in 7.7% of unilateral distal, 13.3% of bilateral distal, 14% of unilateral proximal, and 13.2% of bilateral proximal.

Thrombi in the calf veins can extend to proximal veins, lyse spontaneously, or recanalize over several weeks or months. The evolution of untreated IDDVT in symptomatic outpatients was well-reported in the CALTHRO study.[9] This study suggests that IDDVT can be diagnosed in about 15% of high-risk symptomatic outpatients. Proximal extension within 5–7 days occurs in about 3% of patients while over 90% have complete resolution without anticoagulant treatment.

The balance between clot propagating risk factors and counteracting repair mechanisms in IDDVT is different than in PDVT or pulmonary embolism (PE), and therefore, IDDVT might be regarded as a distinct disease entity, even if it needs to be confirmed in other cohorts.[10] This disease has a prognosis similar to proximal thrombosis, probably due to a more intense thrombophilic status. Patients with bilateral distal vein thrombosis are older and suffer heart failure or respiratory failure, cancer, bed rest, venous insufficiency, recurrence of thrombosis, and higher mortality.

In a systematic review, the proximal extension was reported in 10% of no anticoagulated patients.[10] In the CALTHRO study,[9] propagation into the popliteal vein 5–7 days after the first compression ultrasonography (CUS) was observed in 3.1% of 64 untreated high-risk outpatients.

This result is consistent with findings reported by MacDonald et al.[11] in patients with untreated muscular IDDVT (3%), and with studies that evaluated serial proximal CUS (1% to 5.7%).

Focusing on the embolic potential, data are heterogeneous as in recent systematic reviews, the rate of propagation to proximal veins and PE during surveillance has been reported to range from 0% to 35% and from 0% to 5.8%, respectively, while the prevalence of silent PE was 13%.[12],[13]

In our study, the extension to the proximal veins greatly increases the risk of PE: 4 of 34 patients (11.7%), with calf DVT, who developed PDVT detected by color flow duplex scanning (CFDS) and phlebography, had a subsequent symptomatic PE.[14]

Regarding the late complication, in a study, that involved 154 patients with unprovoked IDDVT, the cumulative risk of recurrence was 17% and 30%, respectively, 10 and 20 years after the diagnosis.[15]

Cancer was the main independent predictive factor of death: patients with cancer-related IDDVT had a nine times higher long-term risk of death compared with subjects without cancer (3.5% vs. 38.3%).[16]

More recently, observations from the GARFIELD-VTE Registry confirmed that DVT location was a less important prognostic factor for recurrence and death in patients with cancer or unprovoked IDDVT.[17]

Postthrombotic syndrome is not a usual complication after distal vein thrombosis: Masuda et al.[18] showed complete lysis of thrombi at 3 months in 88% of distal vein thrombosis studied and at 3 years only 5% of patients had hyperpigmentation and varicose vein development. The postthrombotic syndrome is not correlated to the venous segment involved and symptoms are very few.

Finally, the risk of postthrombotic syndrome was 2.3-fold higher in PDVT patients than in patients affected by IDDVT.[19],[20]

The introduction of CFDS brought advantages in the diagnosis of DVT.[21] More recently,[22] a meta-analysis revealed that a CFDS examination is more sensitive for distal veins (75%vs. 59%) and slightly less specific (94% vs. 98%) as compared with CUS only.

Schellong, et al.[17] affirms that the distal ultrasound, using a well-structured protocol of examination, is a valid 4-min procedure, which can easily be added to the examination of proximal veins.

Two ultrasonographic approaches, both based on vein compression, are validated: the whole-leg ultrasound, consisting in compression ultrasound that may be helped by color flow and spectral Doppler, and the proximal CUS, confining the examination up to the trifurcation area, without detecting calf veins. The latter approach, when negative, has to be repeated after 1 week to exclude proximal extension of a calf thrombosis, assuming that IDDVT may cause complications only in this case, seldom occurring and generally within the first 2 weeks after the onset of symptoms. However, as suggested by the American College of Chest Physicians (ACCP), and more recently by the American Society of Hematology (ASH) guidelines, assessment of pretest probability (PTP) and D-dimer measurements significantly reduced the number of repeated ultrasounds.[23],[24] Hence, while these algorithms have been widely validated for the diagnosis of PDVT, their accuracy in patients with suspected IDDVT is not well defined.

The preference for a proximal rather than a complete ultrasound approach could be safely guided by the presence of symptoms in the calf.[25],[26]

In the PALLADIO study,[27] which enrolled 1162 symptomatic outpatients with suspected DVT, both ultrasound strategies were incorporated, restricting the use of the whole-leg CUS to patients with both a likely PTP and positive D-dimer levels. Safety of the algorithm was demonstrated by the 3-month low incidence of events in untreated patients (0.87%), that neverthless reached 1.49% (95% confidence interval 0.51–4.27) in the highest risk group.

Doubts concerning the safety of a single complete ultrasound in high-risk patients emerged in other studies, and are also raised in the ASH 2018 guidelines for the diagnosis of VTE,[24] and in the recommendations of the Society of Radiologists in Ultrasound Consensus Conference.[28] The Consensus Conference took a net position, suggesting the use of the complete duplex ultrasound as the safest strategy, with CUS at 2 cm intervals from the inguinal ligament to the ankle, spectral Doppler analysis in common femoral and popliteal veins, and color Doppler images. The expert panel emphasized the importance of examining calf veins regardless of the therapeutic strategy.

However, this choice could virtually lead to an increased diagnosis of IDDVT, exposing patients to the risk of overtreatment. In this regard, neither Consensus Conference nor ASH guidelines addressed the screening use of ultrasound in subgroups of asymptomatic high-risk trauma/intensive care patients. This growing practice, which varies among clinicians and hospitals, leads to higher detection of IDDVT difficult to date and of questionable relevance.

A contribution to correctly differentiate between an acute and a chronic thrombosis could possibly be provided by a novel technique, ultrasound elastography, based on the evaluation of tissue elasticity. Its preliminary results are encouraging but need to be confirmed in prospective research.[29]

The therapeutic approach to IDDVT represents a relevant challenge and varies among centers and clinicians.[30]

Few small randomized controlled trials (RCTs) and numerous observational studies, which differed by clinical setting and IDDVT definition (not all authors classified the trifurcation area as proximal, other authors enrolled only patients with clot diameter >5 mm), have analyzed the need for anticoagulation and have compared intensity and duration of different regimens, with discordant results. Since no strategy has been evaluated in the context of sufficiently powered RCTs, guideline recommendations are weak and not based on solid evidence.[31]

In the treatment of IDDVT, Pinede et al.[32] randomized about 200 patients with IDDVT to receive low-molecular-weight heparin (LMWH), followed by oral anticoagulants for 12 weeks or for 6 weeks; the incidence of the thromboembolic events was 3.4% and 2%, respectively, in both groups. The authors concluded that treatment of 6 weeks was adequate.

In another study,[33] the efficacy of treatment with LMWH has been evaluated in patients with isolated thrombosis of the muscular veins of the calf. Patients allocated in the treatment group received subcutaneous full dose, weight-adjusted LMWH, whereas patients allocated in the control group received only graduated compression stockings and clinical surveillance.

Patients belonging to the first group showed no progression to the proximal deep venous system, whereas in the control group, 25% of patients showed an extension of IDDVT in the proximal veins.

Many but not all of the available observational studies[20],[34],[35] have underlined the dangers of conservative management; others have reported an increased risk of major bleeding during anticoagulation. Conversely, in some research, the use of reduced therapeutic regimens resulted a safe strategy, and it has been suggested also by authoritative experts when limited to carefully selected patients.[34],[35] As commented by Sartori and Cosmi both in the CALTHRO and in the CACTUS studies, a 3-month event rate of 8% and 11%, respectively, in untreated patients was not negligible. Instead, in their recent observational study, lower doses of LMWH seemed to be safe, with a low VTE event rate, except for cancer patients.[36],[37]

In recent years, systematic reviews and meta-analyses have been published trying to find stronger evidence from the literature. Many of these have showed that an anticoagulant treatment, even at reduced doses, was safer than conservative management, while others underlined the lack of solid evidence clearly supporting a strategy instead of another.[38],[39],[40] The two most recent meta-analyses showed a significant advantage of the anticoagulation versus no anticoagulation, suggesting that a treatment >6 weeks should be preferred over a shorter duration, as a longer course was associated to a lower rate of recurrent VTE and proximal extension. However, caution is suggested in interpreting these results, as only a few studies have been included in the analysis.[39],[40]

According to the 2016 update of the ACCP guideline, it is probable that not all IDDVT deserve an anticoagulant treatment; patients at high bleeding risk are more likely to benefit from ultrasound surveillance; serial imaging of calf veins for 2 weeks is suggested over anticoagulation (Grade 2C) in patients without severe symptoms or risk factors for extension; otherwise, the treatment is suggested (Grade 2C) “using the same anticoagulation as for PDVT” (Grade 1B).[41]

Whether all IDDVT require an anticoagulant treatment, and what the optimal intensity and duration may be, is currently a gray area and one of the most difficult challenges for clinicians. While in ACCP guideline,[41] both 3 months of therapy and 2 weeks of ultrasound surveillance are suggested, the International Consensus Statement on prevention and treatment of VTE[42] affirmed that 3 months of oral anticoagulant therapy should be prescribed to all patients with symptomatic IDDVT. As advised by experts' opinion, once diagnosed, IDDVT should receive an anticoagulant treatment, whose dose and duration should be reasonably modulated based on the patient's overall risk profile.

  References Top

Johnson SA, Stevens SM, Woller SC, Lake E, Donadini M, Cheng J, et al. Risk of deep vein thrombosis following a single negative whole-leg compression ultrasound: A systematic review and meta-analysis. JAMA 2010;303:438-45.  Back to cited text no. 1
Antignani PL, Aluigi L. The calf vein thrombosis. Rev Vasc Med 2013;1:1-4.  Back to cited text no. 2
Mattos MA, Melendres G, Sumner DS, Hood DB, Barkmeier LD, Hodgson KJ, et al. Prevalence and distribution of calf vein thrombosis in patients with symptomatic deep venous thrombosis: A color-flow duplex study. J Vasc Surg 1996;24:738-44.  Back to cited text no. 3
Gaitini D. Current approaches and controversial issues in the diagnosis of deep vein thrombosis via duplex Doppler ultrasound. J Clin Ultrasound 2006;34:289-97.  Back to cited text no. 4
Naess IA, Christiansen SC, Romundstad P, Cannegieter SC, Rosendaal FR, Hammerstrøm J. Incidence and mortality of venous thrombosis: A population-based study. J Thromb Haemost 2007;5:692-9.  Back to cited text no. 5
De Maeseneer MG, Bochanen N, van Rooijen G, Neglén P. Analysis of 1,338 patients with acute lower limb deep venous thrombosis (DVT) supports the inadequacy of the term “proximal DVT”. Eur J Vasc Endovasc Surg 2016;51:415-20.  Back to cited text no. 6
Bækgaard N. Incidence and location of deep vein thrombosis in the lower extremities: What do we know? Phlebolymphology 2017;24:97-104.  Back to cited text no. 7
Seinturier C, Bosson JL, Colonna M, Imbert B, Carpentier PH. Site and clinical outcome of deep vein thrombosis of the lower limbs: An epidemiological study. J Thromb Haemost 2005;3:1362-7.  Back to cited text no. 8
Palareti G, Cosmi B, Lessiani G, Rodorigo G, Guazzaloca G, Brusi C, et al. Evolution of untreated calf deep-vein thrombosis in high risk symptomatic outpatients: The blind, prospective CALTHRO study. Thromb Haemost 2010;104:1063-70.  Back to cited text no. 9
Palareti G, Schellong S. Isolated distal deep vein thrombosis: What we know and what we are doing. J Thromb Haemost 2012;10:11-9.  Back to cited text no. 10
Macdonald PS, Kahn SR, Miller N, Obrand D. Short-term natural history of isolated gastrocnemius and soleal vein thrombosis. J Vasc Surg 2003;37:523-7.  Back to cited text no. 11
Garry J, Duke A, Labropoulos N. Systematic review of the complications following isolated calf deep vein thrombosis. Br J Surg 2016;103:789-96.  Back to cited text no. 12
Hughes MJ, Stein PD, Matta F. Silent pulmonary embolism in patients with distal deep venous thrombosis: Systematic review. Thromb Res 2014;134:1182-5.  Back to cited text no. 13
Antignani PL, Benedetti Valentini F, Martinelli O, Gossetti B, Righi D, Aluigi L, et al. Isolated Calf Vein Thrombosis and Risk of PE. Acta WFUMB; 2000.  Back to cited text no. 14
Barco S, Corti M, Trinchero A, Picchi C, Ambaglio C, Konstantinides SV, et al. Survival and recurrent venous thromboembolism in patients with first proximal or isolated distal deep vein thrombosis and no pulmonary embolism. J Thromb Haemost 2017;15:1436-42.  Back to cited text no. 15
Galanaud JP, Sevestre-Pietri MA, Bosson JL, Laroche JP, Righini M, Brisot D, et al. Comparative study on risk factors and early outcome of symptomatic distal versus proximal deep vein thrombosis: Results from the OPTIMEV study. Thromb Haemost 2009;102:493-500.  Back to cited text no. 16
Schellong SM, Goldhaber SZ, Weitz JI, Ageno W, Bounameaux H, Turpie AG, et al. Isolated distal deep vein thrombosis: Perspectives from the GARFIELD-VTE Registry. Thromb Haemost 2019;119:1675-85.  Back to cited text no. 17
Masuda EM, Kessler DM, Kistner RL, Eklof B, Sato DT. The natural history of calf vein thrombosis: Lysis of thrombi and development of reflux. J Vasc Surg 1998;28:67-73.  Back to cited text no. 18
Kahn SR, Shrier I, Julian JA, Ducruet T, Arsenault L, Miron MJ, et al. Determinants and time course of the postthrombotic syndrome after acute deep venous thrombosis. Ann Intern Med 2008;149:698-707.  Back to cited text no. 19
Parisi R, Visonà A, Camporese G, Verlato F, Lessiani G, Antignani PL, et al. Isolated distal deep vein thrombosis: Efficacy and safety of a protocol of treatment. Treatment of Isolated Calf Thrombosis (TICT) Study. Int Angiol 2009;28:68-72.  Back to cited text no. 20
Goodacre S, Sampson F, Thomas S, van Beek E, Sutton A. Systematic review and meta-analysis of the diagnostic accuracy of ultrasonography for deep vein thrombosis. BMC Med Imaging 2005;5:6.  Back to cited text no. 21
Schellong SM. Distal DVT: Worth diagnosing? Yes. J Thromb Haemost 2007;5 Suppl 1:51-4.  Back to cited text no. 22
Bates SM, Jaeschke R, Stevens SM, Goodacre S, Wells PS, Stevenson MD, et al. Diagnosis of DVT: Antithrombotic therapy and prevention of thrombosis, 9th ed.: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012;141:S351-418.  Back to cited text no. 23
Lim W, Le Gal G, Bates SM, Righini M, Haramati LB, Lang E, et al. American Society of Hematology 2018 guidelines for management of venous thromboembolism: Diagnosis of venous thromboembolism. Blood Adv 2018;2:3226-56.  Back to cited text no. 24
Schwarz T, Schmidt B, Schmidt B, Schellong SM. Interobserver agreement of complete compression ultrasound for clinically suspected deep vein thrombosis. Clin Appl Thromb Hemost 2002;8:45-9.  Back to cited text no. 25
Gottlieb RH, Voci SL, Syed L, Shyu C, Fultz PJ, Rubens DJ, et al. Randomized prospective study comparing routine versus selective use of sonography of the complete calf in patients with suspected deep venous thrombosis. AJR Am J Roentgenol 2003;180:241-5.  Back to cited text no. 26
Ageno W, Camporese G, Riva N, Iotti M, Bucherini E, Righini M, et al. Analysis of an algorithm incorporating limited and whole-leg assessment of the deep venous system in symptomatic outpatients with suspected deep-vein thrombosis (PALLADIO): A prospective, multicentre, cohort study. Lancet Haematol 2015;2:e474-80.  Back to cited text no. 27
Needleman L, Cronan JJ, Lilly MP, Merli GJ, Adhikari S, Hertzberg BS, et al. Ultrasound for lower extremity deep venous thrombosis: Multidisciplinary recommendations from the Society of Radiologists in Ultrasound Consensus Conference. Circulation 2018;137:1505-15.  Back to cited text no. 28
Mumoli N, Mastroiacovo D, Giorgi-Pierfranceschi M, Pesavento R, Mochi M, Cei M, et al. Ultrasound elastography is useful to distinguish acute and chronic deep vein thrombosis. J Thromb Haemost 2018;16:2482-91.  Back to cited text no. 29
Almosni J, Meusy A, Frances P, Pontal D, Quéré I, Galanaud JP. Practice variation in the management of distal deep vein thrombosis in primary vs. secondary cares: A clinical practice survey. Thromb Res 2015;136:526-30.  Back to cited text no. 30
Horner D, Hogg K, Body R, Nash MJ, Baglin T, Mackway-Jones K. The anticoagulation of calf thrombosis (ACT) project: Results from the randomized controlled external pilot trial. Chest 2014;146:1468-77.  Back to cited text no. 31
Pinede L, Ninet J, Duhaut P, Chabaud S, Demolombe-Rague S, Durieu I, et al. Comparison of 3 and 6 months of oral anticoagulant therapy after a first episode of proximal deep vein thrombosis or pulmonary embolism and comparison of 6 and 12 weeks of therapy after isolated calf deep vein thrombosis. Circulation 2001;103:2453-60.  Back to cited text no. 32
Schwarz T, Schmidt B, Beyer J, Schellong SM. Therapy of isolated calf muscle vein thrombosis with low-molecular-weight heparin. Blood Coagul Fibrinolysis 2001;12:597-9.  Back to cited text no. 33
Palareti G. How I treat isolated distal deep vein thrombosis (IDDVT). Blood 2014;123:1802-9.  Back to cited text no. 34
Masuda EM, Kistner RL, Musikasinthorn C, Liquido F, Geling O, He Q. The controversy of managing calf vein thrombosis. J Vasc Surg 2012;55:550-61.  Back to cited text no. 35
Sartori M, Cosmi B. Anticoagulant therapy for symptomatic calf deep vein thrombosis. Lancet Haematol 2017;4:e156.  Back to cited text no. 36
Sartori M, Lessiani G, Favaretto E, Migliaccio L, Iotti M, Giusto L, et al. Ultrasound characteristics of calf deep vein thrombosis and residual vein obstruction after low molecular weight heparin treatment. Eur J Vasc Endovasc Surg 2016;52:658-64.  Back to cited text no. 37
Huang XC, Hu XH, Wang XR, Zhou CX, Wang GY. Efficacy and safety of therapeutic anticoagulation for the treatment of isolated calf muscle vein thrombosis – A systematic review and meta-analysis. Vasa 2016;45:478-85.  Back to cited text no. 38
Franco L, Giustozzi M, Agnelli G, Becattini C. Anticoagulation in patients with isolated distal deep vein thrombosis: A meta-analysis. J Thromb Haemost 2017;15:1142-54.  Back to cited text no. 39
Lim MS, Ariyarajah A, Oldmeadow C, Hall A, Enjeti AK. A systematic review and meta-analysis comparing anticoagulation versus no anticoagulation and shorter versus longer duration of anticoagulation for treatment of isolated distal deep vein thrombosis. Semin Thromb Hemost 2017;43:836-48.  Back to cited text no. 40
Kearon C, Akl EA, Ornelas J, Blaivas A, Jimenez D, Bounameaux H, et al. Antithrombotic therapy for VTE disease: CHEST Guideline and Expert Panel Report. Chest 2016;149:315-52.  Back to cited text no. 41
Nicolaides AN, Fareed J, Kakkar AK, Comerota AJ, Goldhaber SZ, Hull R, et al. Prevention and treatment of venous thromboembolism – International Consensus Statement. Int Angiol 2013;32:111-260.  Back to cited text no. 42


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