May-Thurner Anatomy in Patients With Chronic Thromboembolic Pulmonary Hypertension: An Important Clinical Association

Validation of the efficacy of the porous medium model in hemodynamic analysis of iliac vein compression syndrome

Iliac Vein Compression Syndrome (IVCS) is a common risk factor for deep vein thrombosis in the lower extremities. The objective of this study was to investigate whether employing a porous medium model to simulate the compressed region of an iliac vein could improve the reliability and accuracy of Computational Fluid Dynamics (CFD) analysis outcomes of IVCS. Pre-operative Computed Tomography (CT) scan images of patients with IVCS were utilized to reconstruct models illustrating both the compression and collateral circulation of the iliac vein. A porous medium model was employed to simulate the compressed region of the iliac vein. The agreements of times to peak between discrete phase particles in CFD analysis and contrast agent particles in Digital Subtraction Angiography (DSA) were compared. Furthermore, comparisons were made between the CFD analysis results that incorporated the porous media and those that did not. The results revealed that in the CFD analysis incorporating the porous media model, more than 80% of discrete phase particles reached the inferior vena cava via collateral circulation. Additionally, the concentration variation curve of discrete phase particles demonstrated a high concordance rate of 92.4% compared to that obtained in DSA. In comparison to CFD analysis conducted without the porous medium model, the incorporation of the porous medium model resulted in a substantial decrease in blood flow velocity by 87.5% within the compressed region, a significant increase in pressure gradient of 141 Pa between the inferior vena cava and left iliac vein, and a wider distribution of wall shear stress exceeding 2.0 Pa in collateral vessels rather than in the compressed region. The study suggests that the introduction of a porous medium model improves the hemodynamic analysis of patients with IVCS, resulting in a closer alignment with clinical observations. This provides a novel theoretical framework for the assessment and treatment of patients with IVCS.

Demographic characteristics, clinical manifestations, and treatment outcomes of May-Thurner Syndrome: a five-year retrospective analysis using computed tomography venography in a Chinese population

OBJECTIVE

This study aimed to analyze the demographic characteristics, symptoms, and treatment outcomes of patients diagnosed with May-Thurner syndrome (MTS) using computed tomography venography (CTV).

METHODS

Medical records of patients diagnosed with MTS through CTV at Hebei General Hospital of China between April 1, 2017, and May 31, 2022, were reviewed. The data collected included: (1) gender, age, body mass index (BMI), and smoking and drinking habits; (2) time of onset and symptoms of MTS, as well as other accompanying symptoms; (3) additional diagnoses, length of hospital stay (days), treatment methods, treatment success, and the occurrence of post-treatment bleeding or recurrence. Descriptive statistics were used, with mean ± standard deviation and median values reported. The t-test/u-test and Chi-square test (including the exact probability method) were used to compare means and rates, respectively, with a significance level set at α = 0.05.

RESULTS

Out of 402 patients (233 males, 169 females), 118 (29.4%) were diagnosed with MTS, with 47 (21.1%) males and 71 (39.7%) females. The incidence of MTS was significantly higher in females than males (χ2 proportion = 16.545, χ2 composition = 9.763, p < 0.05). The average ages of male and female MTS patients were 56.4 and 59.9 years, respectively, with mean BMIs of 27.05 and 27.09 kg/m2. Among male patients, 27.7% (13) were smokers, and 17.0% (8) consumed alcohol. Inferior vena cava (IVC) thrombosis was notable in 59.3% of MTS patients, with a significantly higher proportion in females (70.4%) than in males (42.6%) (χ2 = 9.102, p < 0.05). Lower limb swelling without pain was reported by 70.3% of patients, with 53.4% (44.7% male, 59.2% female) experiencing swelling on the left side only, which was significantly more common than swelling on the right side only or both sides (χ2 = 44.554, p < 0.05). Additionally, 12.7% of patients reported both swelling and pain, with left-side symptoms being more prevalent than right-side or both sides. The average ages at symptom onset were 51.3 ± 17.1 years in males and 57.1 ± 13.2 years in females. All treatments for MTS were successful without bleeding or recurrence. The most common treatment method was balloon dilation combined with stent placement (57.6%).

CONCLUSION

CTV is highly effective in detecting and facilitating the successful treatment of MTS. It should be fully utilized to promote early diagnosis and treatment of MTS. Female MTS patients need more medical resources for diagnosis and treatment.

Familiar Disposition of May-Thurner Syndrome-A Case Series

May-Thurner syndrome is a venous compression syndrome of the pelvic vessels that represents a relevant risk factor for thrombus formation. The standard procedure to secure a diagnosis is venography, followed by endovascular therapy as the preferred treatment choice if the patient is symptomatic. In our case series, there are three related patients with May-Thurner syndrome. A 16-year-old female was admitted with pulmonary embolism, dyspnoea and hip pain. The compression syndrome was diagnosed with interventional venography, and the patient received venous stent implantation. Due to her family history, we also suspected her mother to be affected by the syndrome and elucidated the diagnosis shortly afterwards by invasive venography. Subsequently, we examined the patient's 19-year-old brother, and magnetic resonance imaging confirmed May-Thurner syndrome. A similar case series has not been published before. In this case, the family relation indicates a possible hereditary aspect of May-Thurner syndrome. This hypothesis should be the subject of further research. In conclusion, it is essential to assess family history thoroughly when treating patients with May-Thurner syndrome.

Diagnosis and Management of Pulmonary Hypertension and Right Ventricular Failure in the Cardiovascular Intensive Care Unit

Pulmonary hypertension (PH) encompasses a broad range of conditions, including pulmonary artery hypertension, left-sided heart disease, and pulmonary and thromboembolic disorders. Successful diagnosis and management rely on an integrated clinical assessment of the patient's physiology and right heart function. Right ventricular (RV) heart failure is often a result of PH, but may result from varying abnormalities in preload, afterload, and intrinsic myocardial dysfunction, which require distinct management strategies. Consideration of an individual's hemodynamic phenotype and physiologic circumstances is paramount in management of PH and RV failure, particularly when there is clinical instability in the intensive care setting.

The Clinical Problem of Pelvic Venous Disorders

Pelvic venous disorders are inter-related pathologic conditions caused by reflux and obstruction in the pelvic veins. It can present a spectrum of clinical features based on the route of transmission of venous hypertension to either distal or caudal venous reservoirs. Imaging can help to visualize pelvic vascular and visceral structures to rule out other gynecologic, gastrointestinal, and urologic diseases. Endovascular treatment, owing to its low invasive nature and high success rate, has become the mainstay in the management of pelvic venous disorders. This article reviews the pathophysiology, clinical presentations, and diagnostic and therapeutic approaches to pelvic venous disorders.

Call for Formalized Pathways in Vascular Medicine Training: JACC Review Topic of the Week

The burden of vascular diseases and complexity of their management have been growing. Vascular medicine specialists may help to bridge gaps in care, especially as part of multidisciplinary teams. However, there is a limited number of vascular medicine specialists because of constraints in training. Despite established pathways for training in vascular medicine, there are obstacles that restrict completion of training in dedicated programs. A key factor is lack of funding as a result of inadequate recognition by key national accrediting and credentialing organizations. A concerted effort is required to overcome the obstacles to expand vascular medicine training programs and ultimately the pool of vascular medicine specialists. Well-trained vascular medicine specialists will be well positioned to ease the burden of vascular disease and optimize patient outcomes.