Although participants in our study did not routinely undergo radiographic follow-up, we collected information on the last date of any clinical follow-up at our center and the use of venous duplex ultrasonography, chest computed tomographic angiography, ventilation-perfusion studies, and pulmonary arteriogram studies. We considered bleeding episodes defined as clinically significant blood loss, ie, affecting evaluation or treatment of the patient, independent of transfusion , death, and a composite of proximal DVT, PE, or death as secondary outcomes.
To assess the reliability of exposure and outcome classifications, we had a second blinded rater E. We used logistic regression to estimate the association between the intention to administer therapeutic anticoagulation and subsequent proximal DVT or PE within days. We considered age, sex, body mass index, the aforementioned risk factors for DVT, care setting at the time of calf DVT diagnosis, presence of symptoms or signs prompting calf DVT diagnosis, type of calf DVT, and use of prophylactic anticoagulation during the 7 days before calf DVT diagnosis as factors that potentially confounded this association.
These studies involved unique patients represented repeat studies. Of these patients with a newly identified isolated calf DVT, met exclusion criteria, leaving patients for analysis. The patients included for whom physicians intended to administer therapeutic anticoagulation anticoagulation group and for whom they did not control group. Patients in the 2 groups differed in some baseline characteristics Table 1 and Table 2. Of those intended to receive therapeutic anticoagulation, 1 patient declined treatment.
Of the remaining patients, Delays resulted from obtaining consultations, brief contraindications eg, pending invasive procedure , discussions with the patient, and coordination of care for outpatients. Two patients whom physicians intended not to treat with anticoagulation subsequently received therapeutic anticoagulation in the absence of a proximal DVT or PE 1 for atrial fibrillation and 1 for an upper-extremity DVT.
Therapeutic anticoagulation mainly consisted of warfarin for patients The only departure from standard therapeutic doses involved 1 patient who received warfarin, for whom the target international normalized ratio was 1. Among patients receiving therapeutic anticoagulation for whom the planned duration of treatment was described, physicians planned to administer anticoagulation to 14 Among patients not intended to receive indefinite anticoagulation and for whom the actual duration of anticoagulation was determined, the median duration was interquartile range [IQR], For 86 patients, we were able to determine the planned and actual duration of anticoagulation; the actual duration was a median of 1.
Among of the patients in the anticoagulation group for whom records were sufficient to characterize the adequacy of therapy, Ten of these patients were nonadherent to the regimen; 8 had an episode of bleeding; 2 had a risk for bleeding; and 1 had difficulty titrating the dose of warfarin.
Eighty-one controls The median duration of prophylaxis was 9 IQR, days. Eighty-three patients in the control group In the control and anticoagulation groups, 75 patients Among those tested, the median time to the first follow-up duplex study was 8 IQR, Among the control and anticoagulation groups, 28 patients All underwent chest computed tomographic scan with contrast except for 5 anticoagulation recipients who underwent a ventilation-perfusion scan.
Among those tested, the median times to the first PE study were 22 IQR, days in the control group and 7. Proximal DVT occurred in 7 control group patients 5. Pulmonary embolism occurred in 6 patients in the control group and 4 patients in the anticoagulation group unadjusted RR, 0. The median time to PE diagnosis was With adjustment, intention to administer therapeutic anticoagulation was associated with a reduced likelihood of a composite of proximal DVT, PE, or death. The association among patients with unprovoked calf DVT could not be estimated because only 1 outcome occurred.
Clinically significant bleeding occurred more frequently with anticoagulation Table 3. Among 24 instances, 10 involved the gastrointestinal tract; 5, soft tissue; 4, the genitourinary tract; 4, the central nervous system; and 4, a procedure site locations were not mutually exclusive.
Among 48 patients who died within days, 28 One patient in the anticoagulation group died of a hemorrhagic stroke, and 3 patients in the anticoagulation group died possibly because PE contributed to hypoxia or circulatory insufficiency. Inclusion of records involving a PE diagnosis based on clinical suspicion at the time of calf DVT diagnosis rather than exclusion of such cases only modestly affected the observed association between the intention to administer therapeutic anticoagulation and the primary outcome Table 4.
Among 18 such records, 10 involved no apparent intention to administer therapeutic anticoagulation for the calf DVT before the diagnosis of the PE and 8 involved an intention to administer anticoagulation for the calf DVT. In 16 instances, the PE was diagnosed within 2 days after the calf DVT diagnosis, and all 18 diagnoses were made within 6 days.
Reclassification of the exposure as actual receipt of therapeutic anticoagulation as opposed to intention to administer anticoagulation or as anticoagulation occurring within 1 day of diagnosis of the calf DVT did not substantially change the observed association Table 4.
Restricting the analysis to patients who underwent follow-up testing for DVT or PE also did not appreciably change the observed association. The additional sensitivity analyses similarly did not reveal large differences compared with the primary analysis. Consensus regarding the optimal management of isolated calf DVTs has yet to coalesce, but our study may add weight to arguments for routine inclusion of the calf deep veins in ultrasonography studies and therapeutic anticoagulation for isolated calf DVTs.
Similar to a previous systematic review, 9 we observed a two-thirds reduction in the risk for proximal DVT or PE. The anticoagulation and control groups in our study differed in some characteristics, and specific assumptions of our analysis may have influenced the findings. Nonetheless, neither adjustment for confounders nor sensitivity analyses identified any major concerns about the robustness of the primary findings.
Although the main results were consistent with those of prior studies, our findings also differed in certain respects. Indeed, because we observed so few outcomes among patients with unprovoked calf DVTs, our study may have limited external validity in that population.
These differences are germane because the American College of Chest Physicians guidelines for treating calf DVTs did not consider provoked, multiple, or muscular branch calf DVTs as risk factors for extension. The decision to administer therapeutic anticoagulation to patients with isolated calf DVTs should weigh the risks and benefits for a given patient.
Bleeding episodes, although infrequently life threatening, were clearly associated with therapeutic anticoagulation in our study, and in 1 instance, an unforeseen hemorrhagic stroke directly caused death. The limitations of our study largely pertain to its retrospective, observational nature.
Exposure status could not always be clearly ascertained. Occasionally, intention to administer anticoagulation for the calf DVT could not be unambiguously differentiated from concomitant indications eg, atrial fibrillation.
Of potentially greatest concern, testing for proximal DVT and PE was not applied to all patients, and the indications for and timing of testing were not standardized.
Because our findings hinged on relatively few outcome events, increased testing for DVT and PE in the control group could have biased the results.
Nonetheless, restriction of the analysis to patients who underwent follow-up testing—which presumably would diminish any association attributable to disparity in the use of follow-up testing—did not reveal different results. Residual confounding from unmeasured or unmeasureable factors may have affected our findings. Although radiographic end points have been widely used in studies involving DVT and PE, the extent to which such surrogate outcomes align with true patient-centered outcomes is not well understood.
We did not evaluate 1 such possible patient-centered outcome, postthrombotic syndrome, because we did not think it could be ascertained well from medical records. Because California maintains a statewide data repository with linked hospitalization and emergency department records, a future study may be able to capture such outcomes without having to contact patients and rely on their recall.
Considering these limitations, we conclude that therapeutic anticoagulation of patients with isolated calf DVTs may be warranted to reduce the risk for proximal venous thromboembolism. However, randomized studies are needed to draw firmer conclusions.
Because the benefits of anticoagulation seem modest, we recommend attention to the risk for bleeding when determining whether anticoagulation is appropriate. Corresponding Author: Garth H. Published Online: July 20, Author Contributions: Drs Utter and Dhillon had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Critical revision of the manuscript for important intellectual content: Dhillon, Salcedo, Shouldice, Reynolds, Humphries, White. Conflict of Interest Disclosures: None reported. Our website uses cookies to enhance your experience.
By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy Continue. View Large Download. Table 1. Characteristics of Study Patients. Table 2. Characteristics of the Index Duplex Ultrasonography Test. Table 3. Table 4. Sensitivity Analyses. Risk of deep vein thrombosis following a single negative whole-leg compression ultrasound: a systematic review and meta-analysis.
PubMed Google Scholar Crossref. The case for managing calf vein thrombi with duplex surveillance and selective anticoagulation. Dis Mon. Healthcare Cost and Utilization Project. Accessed October 23, Natural history of postoperative deep-vein thrombosis. Optimal duration of treatment in surgical patients with calf venous thrombosis involving one or more veins. Need for long-term anticoagulant treatment in symptomatic calf-vein thrombosis.
Her past medical history revealed hypertension and chronic ischemic cardiomyopathy treated with angioplasty and stent 8 years before. She was on Lisinopril and Aspirin treatment. She had had her left metatarsal operated the week before, with no post-operative complications. She was discharged with painkillers and subcutaneous low molecular weight heparin LMWH 40 mg daily. Some days later she presented in the ER with tenderness in her left thigh, where an ischemia sleeve was placed for surgery the week before.
On physical examination no signs of inflammation such as erythema or warmth were seen, hence she was discharged with more painkillers. Three days later she referred more pain despite the treatment given. Again, the physical examination revealed no swelling, edema or changes in the left limb circumference.
A CUS was performed in the ER and showed a left thigh hematoma 5 x 21 x 48 mm together with soleal and gastrocnemius deep vein thrombosis. Thus, there was some concern about which would be the optimal management for this patient. Soleal and gastrocnemius DVT are diagnosed with increasingly frequency.
Thrombosis in soleal and gastrocnemius veins can occur in the setting of hematomas affecting limb muscles. Recent travel and presence of leg varicosities are also more prevalent in patients presenting with ISGDVT [6], although no varicosities were seen on physical examination and the patient did not refer a recent travel.
Whenever ISGDVT is suspected, the entire deep venous system between the common femoral vein and popliteal vein distally through the peroneal, anterior tibial, posterior tibial, soleus, and gastrocnemius veins should be evaluated for compressibility at 1 cm intervals. Results are considered positive for DVT if a venous segment is not fully compressible. There is no information whether the entire deep venous system was examined in the present case or not.
The detection of ISGDVT with ultrasonographic assessment depends on the clinical pretest probability and on the availability of trained sonographers. Meticulous examination strategy using a previously stablished protocol is likely to avoid inter and intra observer variability as well as to improve sensibility and specificity of the CUS. Data regarding this issue are limited and come from very few small studies with conflicting findings.
Schwarz et al. No patient in either arm of the study was diagnosed with PE. In contrast, another recent study reported no differences in 3 months progression rates between patients with ISGDVT receiving 10 days of therapeutic LMWH and compression therapy or compression therapy only [11].
This discrepancy may be explained by the fact that in the first study more patients presented persistent risk factors such as cancer or prolonged immobilization. MacDonald et al.
This study showed an overall Furthermore, On the other hand, Gillet et al. The authors found that Reflecting the lack of information on this topic, the most recent consensus from the American College of Chest Physicians regarding antithrombotic therapy for VTE provides no treatment guidelines specific for patients with ISGDVT [14].
Some authors suggested that anticoagulation for ISGDVT may be unnecessary, while others have recommended anticoagulation therapy due to the nontrivial rate of VTE events and the beneficial effects of anticoagulation on these events.
Patients with ISGDVT at risk of subsequent extension may benefit from anticoagulation, but identification of these patients is an unsolved question.
None of these, or combination of these, have been formally tested for their predictive value. Hence, most of Physicians are left to rely on their own judgements. In the present case, a risk factor for subsequent progression is the fact that DVT affects more than one vein both soleal and gastrocnemius veins , in contrast, it seems to be a provoked event following a thigh hematoma and immobilization after metatarsal surgery, all of them known to be transient factors.
No information is given regarding the length of the thrombus or the eventual progression in an eventual second CUS. Thus, given the lack of consensus regarding the benefits of anticoagulation therapy in patients with ISGDVT, I strongly believe that the key factor in our patient is the presence of an evolving thigh hematoma rather than the fact of presenting ISGDVT. In everyday clinical practice there is uncertainty about what to do in patients with ISGDVT, however it is compulsory in this particular case minimizing the bleeding risk and avoiding overtreatment.
As long as the patient presents active hemorrhage, administration of full dose anticoagulation therapy is not recommended. Improvement in venous duplex technology have increased the detection of thrombi in soleal and gastrocnemius deep veins, which to date have been considered to be clinically insignificant.
Many important issues, such as natural course, clinical relevance, risk of progression and optimal treatment of venous thrombosis limited to soleal and gastrocnemius veins still remain unclear which gives rise to discrepancies among Physicians.
Hence, well-designed and properly powered clinical studies addressing the issue of ISGDVT need to be undertaken in order to assess the risks and benefits of anticoagulation in this setting. Figure 1. Schematic representation of leg veins as discussed in this review: 1, external iliac vein; 2, common femoral vein; 3, greater saphenous vein; 4, profound femoral vein; 5, superficial femoral vein; 6, popliteal vein; 7, anterior tibial confluent segment; 8, posterior tibial confluent segment; 9, peroneal confluent segment; 10, anterior tibial veins; 11, posterior tibial veins; 12, peroneal veinss; 13, gastrocnemius muscle veinss medial head ; 14, ssoleuss muscle veins.
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