May-Thurner syndrome and the risk of pulmonary embolism in patients with acute deep venous thrombosis. J Vasc Surg Venous Lymphat Disord. 2018;6:433-440.e1. [PMID: 29909851 DOI: 10.1016/j.jvsv.2018.01.007]

Impact of Common Iliac Vein Compression on the Incidence of Pulmonary Embolism in Patients with Acute Deep Vein Thrombosis

OBJECTIVE

This study aimed to investigate the association between common iliac vein (CIV) compression and pulmonary embolism (PE) in lower extremity deep vein thrombosis (DVT).

METHODS

This was a single centre retrospective study. Between January 2016 and December 2021, DVT patients with enhanced computed tomography of the iliac vein and pulmonary artery were included. Patient demographics, comorbidities, risk factors, and degree of CIV compression were collected and analysed. Logistic regression was performed to evaluate the odds ratio (OR) with a 95% confidence interval (CI) of PE in relation to compression severity groups. The association between PE and compression degree was evaluated with restricted cubic splines (RCS) based on an adjusted logistic regression model.

RESULTS

Two hundred and twenty-six DVT patients (left side, n = 153; right side, n = 73) were included. Univariable analyses suggested that symptomatic or asymptomatic PE (54.4%, 123/226) was more common in men (p = .048) and right side DVT (p = .046) patients. Compared with no CIV compression, multivariable analyses suggested that mild compression did not statistically significantly reduce the PE risk, whereas moderate (adjusted OR 0.36; 95% CI 0.15 - 0.88; p = .025) and severe (adjusted OR 0.18; 95% CI 0.06 - 0.54; p = .002) compression statistically significantly reduced the risk. RCS showed that a smaller minimum diameter or greater compression percentage was correlated with continuously decreasing PE risk at a minimum diameter of < 6.77 mm or compression > 42.9%.

CONCLUSION

PE is more common in men and right side DVT patients. An increasing severity of CIV compression is consistently associated with a decreasing risk of PE when the minimum diameter is < 6.77 mm or the compression is > 42.9%, indicating that it is a protective factor against PE.

The association between iliac vein compression degree and characteristics of first diagnosed left lower extremity deep vein thrombosis

Objective

This study aimed to investigate the association between the left common iliac vein (CIV) compression degree and characteristics of first diagnosed left lower extremity deep vein thrombosis (DVT).

Patients and methods

This was a single-center retrospective observational study. Between January 2015 and June 2022, first diagnosed left lower extremity DVT patients with enhanced computed tomography of lower extremities were included. Patient demographics, comorbidities, risk factors, DVT characteristics, and CIV compression degree were collected and analyzed. Logistic regressions were performed to evaluate the odds ratio (OR) with a 95% confidence interval (CI) of iliofemoral or mixed DVT vs. compression percentage. The association between compression percentage and iliofemoral or mixed DVT was evaluated on a continuous scale with restricted cubic splines (RCS). The association between compression percentage and thrombus burden was evaluated using the Spearman test.

Results

A total of 196 (mean age, 61.8 ± 16.1 years; 86 males) patients were included. The median CIV compression percentage in iliofemoral or mixed DVT patients was significantly greater than in non-iliofemoral or non-mixed DVT, respectively (64.4 vs. 46.6%, p < 0.001; 67.8 vs. 54.8%, p = 0.004). CIV compression >50% was associated with significantly increased morbidity of iliofemoral DVT (adjusted OR, 2.96; 95% CI, 1.58-5.52; p = 0.001) or mixed DVT (adjusted OR, 2.39; 95% CI, 1.19-4.81; p = 0.014). RCS showed that a greater compression percentage was associated with a continuously increased OR of iliofemoral DVT (overall p = 0.003, non-linear p = 0.577) or mixed DVT (overall p = 0.020, non-linear p = 0.771). CIV compression percentage had a positive correlation with thrombus burden (rs = 0.284, p < 0.001).

Conclusion

A greater left CIV compression percentage may be associated with increasing likelihood of more proximal location and severe clot extent in first diagnosed left lower extremity DVT.

Left iliac vein involvement is a protective factor against symptomatic pulmonary embolism in lower left extremity deep vein thrombosis

OBJECTIVE

Left iliac vein compression is associated with left iliac vein thrombosis (IVT), potentially limiting the migration of the thrombus from this stenotic segment to the pulmonary arteries. We sought to investigate the differences in clinical characteristics and risk factors of symptomatic pulmonary embolism (SPE) in patients with deep vein thrombosis (DVT) in different limbs and anatomical locations.

METHODS

A retrospective analysis was conducted of 1476 patients with acute unilateral lower extremity DVT. Differences of clinical characteristics and risk factors between left-sided and right-sided DVT, IVT, and non-IVT, cases with SPE and cases without SPE were compared. Risk factors for SPE were investigated using logistic regression analysis.

RESULTS

SPE was more common in patients with right-sided DVT than patients with left-sided DVT (13.8% vs 7.0%; P < .001). SPE incidence in left IVT (5.4%) was lower than that in left non-IVT, right IVT, and right non-IVT (12.8%, 10.1%, 16.6%, respectively; P < .001). There was no difference in SPE incidence among patients with left non-IVT, right IVT and right non-IVT (P > .05). In patients with left-sided DVT, male sex was associated with an increased odds of SPE (odds ratio [OR], 1.77; 95% confidence interval [CI], 1.10-2.85; P = .02). IVT, surgery, and immobilization were associated with a decreased odds of SPE (OR, 0.46 [95% CI, 0.28-0.76; P < .01]; OR, 0.55 [95% CI, 0.32-0.95; P = .03]; and OR, 0.53 [95% CI, 0.32-0.86; P = .01]). In patients with right-sided DVT, provoked DVT was associated with a decreased odds of SPE (OR, 0.50; 95% CI, 0.27-0.93; P = .03).

CONCLUSIONS

Left IVT is associated with a lower SPE incidence than right-sided DVT. Left IVT and may be a relative protective factor against SPE.

Clinical outcomes of AngioJet rheolytic thrombectomy in the treatment of May-Thurner syndrome-related deep venous thrombosis

Objective

May–Thurner syndrome (MTS) is an anatomic stenotic variation associated with deep vein thrombosis (DVT) of the left leg. The classical DVT treatment strategy is medical treatment without thrombus removal. This study was performed to assess the clinical outcomes of the combination of AngioJet™ rheolytic thrombectomy and stenting for treatment of MTS-related DVT.

Methods

We conducted a retrospective cohort study of patients treated for MTS-related DVT from January 2017 to June 2020 at a single institution.

Results

Fourteen patients (nine women) underwent AngioJet™ rheolytic thrombectomy for MTS-related DVT during the study period. The median DVT onset time was 8 days (interquartile range (IQR), 3–21 days). The median procedure time was 130 minutes (IQR, 91–189 minutes), and the median hospital stay was 7 days (IQR, 5–26 days). One patient had a residual thrombus and occluded iliac stent and underwent adjuvant catheter-directed thrombolysis for revascularization. The primary patency rate for the iliac stent was 92.9% at 12 months.

Conclusion

Concomitant AngioJet™ rheolytic thrombectomy and stenting of MTS-induced lesions may be beneficial for patients with MTS-related DVT.

Percutaneous endovenous intervention without vena cava filter for acute proximal deep vein thrombosis secondary to iliac vein compression syndrome: preliminary outcomes

The aim is to report the preliminary outcomes of percutaneous endovenous intervention (PEVI) for acute proximal deep vein thrombosis (DVT) secondary to iliac vein compression syndrome (IVCS) without inferior vena cava filter (IVCF) placement. Acute DVT patients who underwent PEVI without IVCF were analyzed retrospectively. PEVI consisted of catheter-directed thrombolysis, manual aspiration thrombectomy, balloon angioplasty and stenting. CT was used to evaluate the left common iliac vein (LCIV). Sixty-two consecutive patients (17 men and 45 women, mean age, 59.4 ± 15.2 years) were enrolled. The compression percentage of the LCIV ranged from 51.7% to 95.2% (median 83.2%). Iliac DVT was present in 7 patients; iliofemoral, in 30 patients; and iliofemoropopliteal, in 25 patients. Complete technical success and clinical improvement were obtained in all subjects without the occurrence of symptomatic pulmonary embolism (PE). Five patients experienced recurrent thrombosis. The primary patency rates at 12 and 24 months were 93.8% and 91.4%, respectively, which remained stable at 36, 48 and 60 months. The secondary patency rates at 12 and 24 months were 95.7% and 93.3%, respectively, and there was no change at 60 months. Although limited, our preliminary results suggested that PEVI without IVCF placement seemed to be safe and effective for acute proximal DVT secondary to IVCS without inferior vena cava thrombosis or symptomatic PE.

Review of imaging and endovascular intervention of iliocaval venous compression syndrome

Iliocaval venous compression syndrome (ICS) is the extrinsic compression of the common iliac vein by the overlying iliac artery against the vertebra. Chronic compression can lead to venous stenosis and stasis, which manifests as chronic venous disease and treatment resistance. Therefore, early recognition of ICS and prompt treatment are essential. Clinical presentations of ICS can be ambiguous and diagnosis requires a high index of suspicion with the relevant imaging studies. The initial imaging test is typically a Duplex ultrasound for vessel assessment and pelvic ultrasound to exclude a compressive mass, which is followed by computed tomography (CT) or magnetic resonance (MR) venography. CT and MRI can identify the anatomical causes for venous compression. In patients with high clinical suspicion for ICS, negative findings on CT and MR venography would still warrant further investigations. Definitive diagnosis can be established using catheter-based venography complemented with intravascular ultrasonography but the nature of their invasiveness limits its utility as a routine imaging modality. In this review paper, we will discuss the evidence, utility and limitations of the existing imaging modalities and endovascular intervention used in the management of ICS.

Acute pulmonary embolism unmasking underlying chronic thromboembolic pulmonary hypertension and iliac vein compression syndrome

We describe the case of a 72-year-old gentleman who was referred to our institution for management of cardiogenic shock from a massive pulmonary embolism. Right heart catheterization revealed a low cardiac index and markedly elevated pulmonary pressures, suggested long-standing venous thromboembolic (VTE) disease that evolved into chronic thromboembolic pulmonary hypertension (CTEPH). The patient was cannulated to veno-arterial extra-corporeal membrane oxygenation and eventually treated with pulmonary embolectomy and thromboendarterectomy. Subsequently discovered inferior vena cava clot and left iliac deep vein thrombosis were treated with suction and mechanical thrombectomy. Intravascular ultrasound of the left lower extremity venous system identified iliac vein compression syndrome (IVCS) as the culprit of the patient's VTE and CTEPH. A left iliac stent was placed and the patient was discharged on Warfarin for anticoagulation. The case illustrates the rapidly expanding armamentarium for VTE treatment and proposes IVCS as a new, potentially underrecognized risk factor for CTEPH.

Modifying ICCA with Trp-Phe-Phe to Enhance in vivo Activity and Form Nano-Medicine

BACKGROUND

1-(4-isopropylphenyl)-β-carboline-3-carboxylic acid (ICCA) was modified by Trp-Phe-Phe to form 1-(4-isopropylphenyl)-β-carboline-3-carbonyl-Trp-Phe-Phe (ICCA-WFF).

PURPOSE

The object of preparing ICCA-WFF was to enhance the in vivo efficacy of ICCA, to explore the possible targeting action, and to visualize the nano-feature.

METHODS

The advantages of ICCA-WFF over ICCA were demonstrated by a series of in vivo assays, such as anti-tumor assay, anti-arterial thrombosis assay, anti-venous thrombosis assay, P-selectin expression assay, and GPIIb/IIIa expression assay. The nano-features of ICCA-WFF were visualized by TEM, SEM and AFM images. The thrombus targeting and tumor-targeting actions were evidenced by FT-MS spectrum analysis.

RESULTS

The minimal effective dose of ICCA-WFF slowing tumor growth and inhibiting thrombosis was 10-fold lower than that of ICCA. ICCA-WFF, but not ICCA, formed nano-particles capable of safe delivery in blood circulation. In vivo ICCA-WFF, but not ICCA, can target thrombus and tumor. In thrombus and tumor, ICCA-WFF released Trp-Phe-Phe and/or ICCA.

CONCLUSION

Modifying ICCA with Trp-Phe-Phe successfully enhanced the anti-tumor activity, improved the anti-thrombotic action, formed nano-particles, targeted tumor tissue and thrombus, and provided an oligopeptide modification strategy for heterocyclic compounds.