Clinical Hemorheology and Microcirculation

COVID-19 causes a considerable degradation of pulmonary function to the point of an acute respiratory distress syndrome (ARDS). Over the course of the disease the gas exchange capability of the lung can get impaired to such an extent that extracorporeal membrane oxygenation (ECMO) is needed as a life-saving intervention. In patients COVID-19 as well as ECMO may cause severe coagulopathies which manifest themselves in micro and macro thrombosis. Previous studies established D-dimers as a marker for critical thrombosis of the ECMO system while on admission increased D-dimers are associated with a higher mortality in COIVD-19 patients. It is therefore crucial to determine if COVID-19 poses an increased risk of early thrombosis of the vital ECMO system.

40 patients who required ECMO support were enrolled in a retrospective analysis and assigned into 2 groups. The COVID group consist of 20 COVID-19 patients who required ECMO support (n = 20), whereas 20 ECMO patients without COVID-19 were assigned to the control group. D-dimers, fibrinogen, antithrombin III (AT III), lactate dehydrogenase (LDH) and platelet count were analysed using locally weighted scatterplot smoothing and MANOVAs.

The analysis of both groups shows highly significant differences in the dynamics of hemostasis. The increase in D-dimers that is associated with thrombosis of the ECMO systems occurs in COVID-19 patients around 2 days earlier (p = 2,8115 10^–11) while fibrinogen is consumed steadily. In the control group fibrinogen levels increase rapidly after ten days with a plateau phase of around five days (p = 1,407 10^–3₎ . Both groups experience a rapid increase in AT III after start of support by ECMO (p = 5,96 10^–15). In the COVID group platelet count decreased from 210 giga/l to 130 giga/l within eight days, while in the same time span in the control group platelets decreased from 180 giga/l to 105 giga/l (p = 1,1 10^–15). In both groups a marked increase in LDH beyond 5000 U/l occurs (p = 3,0865 10^–15).

The early increase in D-dimers and decrease in fibrinogen suggests that COVID-19 patients bear an increased risk of early thrombosis of the ECMO system compared to other diseases treated with ECMO. Additionally, the control group shows signs of severe inflammation 10 days after the start of ECMO which were absent in COVID-19 patients.

Arteriovenous malformations (AVMs) are vascular anomalies characterized by abnormal shunting between arteries and veins. The progression of the AVMs and their hemodynamic and rheological relations are poorly studied, and there is a lack of a feasible experimental model.

To establish a model that cause only minimal micro-rheological alterations, compared to other AV models.

Sixteen female Sprague Dawley rats were randomly divided into control and AVM groups. End-to-end anastomoses were created between the saphenous veins and arteries to mimic AVM nidus. Hematological and hemorheological parameters were analyzed before surgery and on the 1^st, 3^rd, 5^th, 7^th, 9^th, and 12^th postoperative weeks.

Compared to sham-operated Control group the AVM group did not show important alterations in hematological parameters nor in erythrocyte aggregation and deformability. However, slightly increased aggregation and moderately decreased deformability values were found, without significant differences. The changes normalized by the 12^th postoperative week.

The presented rat model of a small-caliber AVM created on saphenous vessels does not cause significant micro-rheological changes. The alterations found were most likely related to the acute phase reactions and not to the presence of a small-caliber shunt. The model seems to be suitable for further studies of AVM progression.

Even though cardiovascular stenting is widely used for the treatment of coronary artery disease, information on how it can affect the hematological and hemorheological profile is scarce in the literature. Most of the work on this issue is based on theoretical or computational fluid dynamics models, lacking in-depth in vitro and in vivo experimental verification.

This work investigates, in an in vivo setting, the effects of stenting and the implantation time-course on hematological and hemorheological parameters that could potentially compromise the device’s functionality and longevity.

Custom-made self-expanding nitinol stents were implanted in the common carotid artery of male CD1 mice. Whole blood samples were collected from control (non-stented) and stented animals at 5 and 10 weeks post-implantation. Hematological measurements and blood viscosity, red blood cell aggregation, and deformability were performed using standard techniques.

Implant-induced changes were observed in some of the hematological and hemorheological indices. Blood viscosity seems to have been negatively affected by an increased hematocrit and reduced RBC deformability, at 10 weeks post-implantation, despite a slight decrease in RBC aggregation.

Although the alterations observed may be the result of the peri-implant inflammatory response, the physiological consequences due to hemorheological changes need to be further investigated.

Hepatic sarcomatoid carcinoma (HSC) is a rare malignancy of the liver. The ultrasound and clinical features of HSC have not been determined.

To investigate and compare the ultrasound and clinical features of HSC and hepatocellular carcinoma (HCC), and to reveal the valuable features of HSC.

The ultrasound features and clinical data of pathologically proven HSC (n = 37) were compared with HCC (n = 92) in a matching ratio of 1:4 using the propensity score (age, gender and tumor size).

The HSC patients were more likely to accompany with clinical symptoms and vascular invasion than HCC patients (40.5% vs 17.4%, 24.3% vs 6.5%, P < 0.05). The size of HSCs was significantly larger than that of HCCs (P < 0.05). The proportion of patients with elevated alpha-fetoprotein was significantly lower in HSC (35.1% vs 54.3%, P < 0.05). On gray-scale ultrasound images, the HSCs were more likely to demonstrate as indistinct margin and irregular shape lesions compared to HCCs (78.4% vs 48.8%; 70.3% vs 23.9%, P < 0.05). Under color Doppler flow imaging (CDFI), the blood flow signals were more frequently detected in HSC lesions (75.7% vs 56.5%, P < 0.05). Resistance index (RI) was higher in HSCs than in HCCs [0.78 (0.70,0.82) vs 0.70 (0.62,0.76), P < 0.05]. On contrast-enhanced ultrasound (CEUS), HSCs mainly showed entirety heterogeneous hyper-enhancement (48.6%), entirety homogeneous enhancement (18.9%), peripheral and internal septal enhancement (18.9%). The incidence of non-enhanced areas inside HSC lesions was higher than that inside HCC lesions (56.8% vs 31.5%, P < 0.05). During the portal venous and late phases, most of the lesions revealed hypo-enhancement in both groups, whereas earlier washout was observed in HSCs [43.0 s (30.5,58.0) vs 60.0 s (46.3,100.0), P < 0.05].

CEUS features are useful in preoperative and non-invasive differentiation of hepatic sarcomatoid carcinoma and hepatocellular carcinoma.

The popliteal artery is highly exposed to biomechanical stress, which is the primary factor associated with stent failure. However, information on the optimal endovascular treatment for the popliteal artery is lacking.

To report the efficacy of the GORE^® TIGRIS^® Vascular Stent for the endovascular treatment of popliteal artery lesions.

Retrospective analysis of all patients with symptoms of peripheral artery occlusive disease (PAD) and popliteal artery lesions who underwent implantation of a GORE^® TIGRIS^® Vascular Stent between August 2012 and August 2014 at a tertiary vascular centre.

Between August 2012 and August 2014, 48 patients (32 men, aged 75±8 years) were treated with a GORE^® TIGRIS^® Vascular Stent. The technical success rate was 100%. At 12 months, the primary and secondary patency rates were 74% and 85%, respectively. During follow-up, no stent fracture was observed. No major amputations were performed.

Our study showed that isolated popliteal artery lesions in patients with symptomatic PAD could easily be treated with the GORE^® TIGRIS^® Vascular Stent, as good short-term results were achieved at 12 months. Therefore, the discontinuation of this product removed a useful tool with a simple release mechanism from the endovascular armamentarium of vascular specialists.

To evaluate the efficacy and safety of percutaneous ultrasound-guided thermal ablation in the treatment of cervical metastatic lymph nodes (LNs) from papillary thyroid carcinoma (PTC).

A total of 77 patients with 79 LNs ablated by microwave ablation (MWA) or radiofrequency ablation (RFA) between September 2018 and October 2022 were enrolled in this study. After treatment, patients were followed up with measurement of diameters of LNs and serum thyroglobulin (s-Tg) at 1, 3, 6, and 12 months and annually thereafter. The paired t-test was used to compare the changes of s-Tg level, diameters of LNs before and after ablation.

There were no serious complications related to ablation while one case of incomplete ablation in MWA was found during follow-up. The mean longest and shortest diameter of the ablated LNs reduced from 11.6 ± 4.3 mm to 5.0 ± 4.1 mm (p < 0.001), and from 6.1 ± 1.9 mm to 3.0 ± 2.5 mm (p < 0.001) at the last follow-up visit. Besides, the final volume reduction rate (VRR) was 61.8 ± 56.4% (range, –67.0 –100%). The complete disappearance rate was 46.8%, but there were 4 (5.1%) LNs becoming bigger than before. The average s-Tg level was 9.2 ± 26.6 ng/mL, a data significantly decreased to 3.7 ± 7.0 ng/mL at the last follow-up, but no statistical difference was shown.

Thermal ablation is an effective and safe modality for the treatment of metastatic LNs from PTC.

Post-occlusive reactive hyperemia (PORH) typically requires caffeine abstinence. For habitual users, it is unknown if abstinence affects PORH.

Compare PORH after habitual users consume or abstain from caffeine.

On separate visits (within-subject), PORH was measured in 30 participants without abstinence from typical caffeine doses (CAFF) and with abstinence (ABS). Measurements included baseline and peak hyperemic velocity, tissue saturation index slopes during ischemia (Slope 1) and following cuff deflation (Slope 2), resting arterial occlusion pressure (AOP), heart rate (HR), systolic (SBP), and diastolic (DBP) blood pressure. All variables were compared using Bayesian paired t-tests. BF₁₀ = likelihood of alternative vs null. Results are mean±SD.

Comparing baseline velocity (cm/s) between CAFF (9.3±4.8) and ABS (7.5±4.9) yielded anecdotal evidence (BF₁₀ = 1.0). Peak hyperemic velocity (cm/s) was similar (CAFF = 77.3±16.7; ABS = 77.6±19.0, BF₁₀ = 0.20). For slopes (TSI% /s), CAFF Slope 1 = –0.11±0.04 and Slope 2 = 1.9±0.46 were similar (both BF₁₀≤0.20) to ABS Slope 1 = –0.12±0.03 and Slope 2 = 1.8±0.42. SBP and DBP (mmHg) were both similar (CAFF SBP = 116.0±9.8, DBP = 69.6±5.8; ABS SBP = 115.5±10.7, DBP = 69.5±5.4; both BF₁₀≤0.22). Comparing AOP (mmHg) (CAFF = 146.6±15.0; ABS = 143.0±16.4) yielded anecdotal evidence (BF₁₀ = 0.46). HR (bpm) was similar (CAFF = 66.5±12.3; ABS = 66.9±13.0; BF₁₀ = 0.20).

In habitual users, consuming or abstaining from typical caffeine doses does not appear to affect post-occlusive reactive hyperemia.

Acute stroke poses a serious threat to people’s health. The occurrence of a thrombus following the rupture of vulnerable plaques in the carotid artery is a significant contributor to the development of stroke. In previous case reports, it has been challenging to visualize tiny ulcerations within carotid artery plaques using computed tomography angiography (CTA) and digital subtraction angiography (DSA), even when the rupture of the plaque leads to the formation of a free-floating thrombus (FFT). However, in this particular case, contrast-enhanced ultrasound (CEUS) was able to overcome this limitation and provide a more precise assessment, confirming that the FFT formation was indeed a result of plaque rupture rather than any other potential causes. Cases that utilize CEUS to visualize the formation of ulcers and FFT resulting from plaque rupture are even more rare. As such, we present this case to shed light on this infrequent phenomenon.

In this case study, we present a 65-year-old male patient who was admitted to the hospital due to headache and abnormal mental behavior for one day. During the routine cervical artery ultrasound examination upon admission, we detected the presence of plaque in the right internal carotid artery of the patient, resulting in luminal stenosis. Additionally, we observed suspected hypoechoic material at the distal end of the plaque. After undergoing CEUS examination, it was definitively determined that an ulcer had formed and a FFT had developed due to the rupture of carotid artery plaque. Subsequent CTA and DSA examinations further confirmed the presence of the FFT. The magnetic resonance imaging (MRI) reveals an acute lacunar infarction in the head of the right caput nuclei caudate, which strengthens the potential link between the patient’s neurological and psychiatric symptoms observed during admission. The patient received prompt antiplatelet therapy and underwent cervical artery stenting surgery with the assistance of a distal embolic protection device. Following the procedure, the patient was discharged on the fourth day and experienced a complete recovery.

CEUS is a valuable tool for visualizing FFT resulting from the rupture of vulnerable plaques in the carotid artery.

It is rare for intraductal papilloma (IDP), a benign papillary tumor, to occur in the sublingual gland (SLG).

A 55-year-old man incidentally found a painless mass in his left submandibular region (SMR). He had a history of two surgeries for bilateral SLG cyst. Contrast enhanced ultrasound (CEUS) and magnetic resonance imaging (MRI) were performed. The patient received trans-cervical excision of left residual SLG in combination with excision of left submandibular gland (SMG). The postoperative course was uneventful and no signs of recurrence during 5 months of follow-up.

For a SMR mass, extraoral type of IDP in SLG should be considered in the differential diagnosis.