Clinical Hemorheology and Microcirculation

Chronic venous disease (CVD) is extremely common worldwide with prevalence increasing with age. It is associated with a reduced quality of life, particularly in relation to pain, physical function and mobility. Symptomatic chronic venous insufficiency (CVI) with venous ulcer at its’ endpoint, indicates interventional surgery to cure venous reflux therewith promoting wound healing and preventing recurrence. In this retrospective, single-centre, consecutive case-control study in a single patient population of a university clinic in northern Germany a holistic evaluation of varicose vein surgeries has been undertaken. Part I covered postoperative complications in relation to co-morbidities, co-medication and clinical presentation. Part II of this article presents now the hemodynamic results in relation to the perioperative evolution of CVI specific symptoms.

Records of n = 429 (467 extremities) patients from 2009-2013 treated with open surgery were analysed with regards to perioperative hemodynamics. Evolution of CVI symptomology was accessed postoperatively with the help of a questionnaire and patient records in the case of complication development. Venous hemodynamics was analysed in the whole patient population and with regards to complication subgroups: no events (NE), neglectable adverse events (NAE) and non-neglectable adverse events (NNAE).

Postoperatively, patients’ CVI-symptoms like pain (p < 0.001), swelling (p < 0.001) and itching (p = 0.003) significantly improved. The venous refill time and venous pump capacity improved significantly after open vein surgery (p < 0.05). Regardless of the development of postoperative complications there was a significant improvement of venous function at 6 weeks- and one-year postoperative in follow-up (p < 0.05). Symptom regression was strongly correlated with hemodynamic improvement.

A significant improvement of patients’ symptoms was achieved by means of open-surgery, regardless of postoperative complication development. This was in accordance with the improvement of venous hemodynamics. A strong correlation between symptom regression and improvement in venous hemodynamics could be proven.

The laser Doppler fluxmetry (LDF) is a non-invasive method to assess skin blood perfusion, measuring the flow of blood cells inside a tissue volume without harming the tissue. In the diagnosis of skin circulation disorders, the results of the LDF measurement are generally used in such a way that “normal” (or non-ill) or “pathological” values are achieved by comparison with a reference sample, for example of apparently healthy subjects.

In this study, the values of LDF for the diagnosis of microcirculatory disorders in patients with coronary artery disease (n = 20) or in patients with microcirculatory disorders, already diagnosed by capillary microscopy (n = 46), were examined.

The mean values of LD amplitudes in the four frequency windows for patients with coronary artery disease were in the reference range. However, some of the patients showed reduced LD values: in eleven of the twenty patients, one or more mean LD amplitudes were below the reference range. Four of the eleven patients had pathologically decreased capillary erythrocyte velocities of v_ery = 0.09–0.21 [mm/s], while the other seven patients had normal blood circulation at rest.

For all patients with a proven cutaneous microcirculatory disorder, the mean LD amplitude in at least one of the frequency windows FF2 to FF4 was pathologically reduced.

The Laser-Doppler fluxmetry method used in the study allows the reliable diagnosis of cutaneous microcirculatory disorders.

The first method of choice for gallbladder alteration detection is the conventional ultrasound. Due to some imaging limitations, contrast-enhanced ultrasound (CEUS) has been widely used in the last years. CEUS is an additional modality that is able to depict microvessels flow and elucidate suspicious findings.

The aim of this retrospective mono-center analysis study is to evaluate the performance of CEUS in gallbladder diseases and compare it to cross-sectional imaging modalities and histopathological results as gold standard.

The retrospective study analysed 37 patients with gallbladder diseases between 2009 and 2017. All patients underwent CEUS examinations and additional cross-sectional imaging was also performed: CT imaging on 24 (64.9%) patients, MRI imaging on 18 (48.6%) patients, CT and MRI imaging on (28.7%). CEUS images were performed and interpreted by a single physician.

CEUS imaging results of the gallbladder showed a sensitivity and specificity of 100%, a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 100%. CT imaging of the gallbladder showed a sensitivity of 100%, specificity of 75%, PPV of 100%, and NPV of 95%. MR imaging of the gallbladder showed a sensitivity of 100%, specificity of 93%, PPV of 75%, and NPV of 100%.

Ultrasound imaging plays an essential role in the evaluation of gallbladder disease. Due to additional features of contrast-enhanced ultrasound, it is possible to differentiate gallbladder pathologic alterations by depicting its micro and macrocirculation and display important malignant features that recommends prompt management. Patients with contraindications to other cross-sectional imaging modalities benefit from this safe technique.

Radiologic imaging, especially ultrasound has an important role in the assessment of gallbladder alteration. Contrast-enhanced ultrasound (CEUS) is an easy and fast imaging technique that overcomes the limitations of greyscale ultrasonography. It is a safe tool that can be used as an additional imaging modality in order to elucidate and differentiate gallbladder pathological findings.

The aim of this retrospective study analysis is to assess the diagnostic performance of CEUS in gallbladder alterations and compare the results to the histopathological findings.

A total of 17 patients between 2009 and 2017 with uncertain gallbladder appearance were retrospectively analysed. A single experienced physician with more than fifteen years’ experience performed CEUS examinations by applying a second-generation blood pool agent (SonoVue^®, Bracco, Milan, Italy). Archived images were interpreted by the same physician and compared to the histopathological findings.

CEUS results, when correlated to the respectively pathologic findings, presented a sensitivity of 100%, a specificity of 100%, a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 100%. All patients were successfully examined without any adverse reaction.

In conclusion, the excellent results in this study acknowledged that CEUS is a feasible alternative tool to differentiate gallbladder pathologic alterations.

Renal cell carcinomas (RCC) represent a heterogeneous group of hypo- and hypervascularized malignancies. Using contrast-enhanced ultrasound (CEUS) specific imaging features of clear cell (ccRCC), papillary (pRCC) and chromophobe RCC (chRCC) subtypes have been demonstrated. However, some RCCs show atypical imaging features making it difficult to distinguish between the subtypes.

This study was performed to evaluate the observed enhancement features of pRCC in CEUS and to assess the sensitivity in the diagnosis of suspected renal malignancies in a 10 year retrospective analysis at our institution.

The study population consisted of 60 patients with histologically confirmed pRCC. All patients underwent CEUS imaging between 2005 and 2015 as part of their diagnostic workup.

In 45 out of 60 (75%) cases the examined pRCC showed typical hypoenhancement and wash-out. 15 out of 60 (25%) pRCC showed atypical enhancement features; in 14 cases the contrast enhancement indicated a ccRCC. 1 complex cyst was falsely reported as IIF lesion. 59 out of 60 malignancies were reported as malignant using CEUS resulting in a sensitivity of 98.4%.

CEUS is an eligible imaging technique to visualize the contrast enhancement features of pRCC. However, up to 25% of pRCCs show an atypical enhancement pattern making it difficult to distinguish it from other renal lesions.

We aimed to evaluate whether PIRADS 3 lesions in multiparametric MRI (mpMRI) represent a significant risk of prostate cancer (PCa) in a real-world setting of different referring radiologic institutes.

Between May 2015 and October 2017, a total of 408 patients were referred to our clinic for MRI-ultrasound fusion targeted biopsy of the prostate (FusPbx) due to suspected prostate cancer. In all patients, preoperatively an mpMRI of the prostate was performed by altogether 62 different radiologic institutes. Prostate lesions were classified according to the PIRADS system. A PIRADS 3 lesion was diagnosed in 41 patients. FusPbx was performed transrectally using a Philips EPIQ 7 (Philips Medical Systems, Bothell, WA) scanner with plane wise fusion of ultrasound and MRI image data. In addition to FusPbx in each patient a randomized 12-core transrectal ultrasound guided biopsy (USPbx) was performed.

Mean PSA Level was 9.5 ng/ml (range: 1– 26 ng/ml), mean patients age was 66.1 years (48.6– 80.4). In 11/41 patients (26.8%) prostate cancer was diagnosed by FusPbx of the PIRADS 3 lesion. In the target lesion PCa was classified as Gleason Score 3+3 in 5 patients, as 3+4 in 3, 4+3 in 1, 4+4 in 1 and 4+5 in 1 patient. In patients with negative FusPbx USPbx revealed PCa in another 7 patients (17.1%). In 5 of these GS 3+3 PCa was found, in another 2 patients GS 3+4 PCa.

PIRADS 3 lesion indicates an equivocal likelihood of significant prostate cancer. In our series the overall PCa detection rate was 26.8% and 14.6% for clinically significant cancer in PIRADS 3 lesions. This evokes the question, if PIRADS 3 lesions could be surveilled only. The findings should be confirmed in a larger series.

While complication rates in free tissue transfers have continuously decreased over time due to improved techniques, the intraoperative use of vasopressors and their negative effects on flap microcirculation and patency of the anastomoses remains controversial. To further elucidate this matter, this retrospective study examines the effect of intraoperative vasopressors on free gracilis muscle and free fasciocutaneous anterolateral thigh (ALT) flaps for lower extremity reconstruction.

A total of 425 patients underwent 437 free flaps for lower limb reconstruction. The series was divided into two groups: use of intraoperative vasopressors (V, n = 318) or no use (NV, n = 119). The data were retrospectively screened for patients’ demographics, perioperative details, and surgical complications.

The two groups were comparable regarding patient comorbidities. Independently of flap type, there were no significant difference between the groups regarding major complications, i.e. total flap loss (V: 5.35% versus NV: 5.04%, p = 0.899) or revision rate (V: 18.87% versus NV: 12.61%; p = 0.122), or minor complications, i.e. partial flap loss (V: 6.29% versus NV: 5.88%, p = 0.875).

This study confirms that the usage of intraoperative vasopressors has no influence on free flap survival rate in lower extremity reconstruction. It seems to be no difference between free muscle or fasciocutaneous flaps.

Red blood cells (RBC) are exposed to varying shear stress while traversing the circulatory system; this shear initiates RBC-derived nitric oxide (NO) production.

The current study investigated the effect of varying shear stress dose on RBC-derived NO production.

Separated RBC were prepared with the molecular probe, diamino-fluoreoscein diacetate, for fluorometric detection of NO. Prepared RBC were exposed to discrete magnitudes of shear stress (1–100 Pa), and intracellular and extracellular fluorescence was quantified via fluorescence microscopy at baseline (0 min) and discrete time-points (1–30 min).

Intracellular RBC-derived NO fluorescence was significantly increased (p < 0.05) following shear stress exposure when compared to baseline at: i) 1 min–100 Pa; ii) 5 min–1, 5 Pa; iii) 15 min–1, 5, 35 Pa; iv) 30 min–35 Pa. Extracellular RBC-derived NO fluorescence was significantly increased (p < 0.05) following shear stress exposure when compared to baseline at: i) 5 min – 100 Pa; ii) 15 min–100 Pa; iii) 30 min–40, 100 Pa.

These data indicate that: i) a dose-response exists for the RBC-derived production of NO via shear stress; and ii) exposure to supra-physiological shear stress allows for the leakage of RBC intracellular contents (e.g., RBC-derived NO).

L-Arginine, the precursor of NO might be involved in improving the cardiovascular disorders via regulation of functional properties of erythrocytes.

This study investigated the effects of L-Arginine supplementation on responses of red blood cell (RBC) properties to high intensity interval exercise (HIIE).

Ten overweight healthy men participated voluntarily in the study and performed two HIIE trials with and without L-Arginine in two separate weeks. The HIIE protocol included 12 intervals of 3-min encompassed 1-min running at 100% of vVO₂max and 2-min active recovery at 40% of vVO₂max. Three blood samples were taken before and after supplementation, and immediately after exercise; and were used to measure red blood cell properties.

The HIIE protocol increased hematocrit, hemoglobin and lactate significantly (P < 0.05), but had no significant effect on RBC aggregation, RBC deformability, and fibrinogen concentration. When data were compared for two trials no significant differences between the responses of RBC properties to two HIIE protocols were detected (P > 0.05), whereas the increases in lactate concentration following HIIE was significantly lower in L-Arginine than placebo trial (P < 0.05).

It is concluded that L-Arginine consumption prior to HIIE does not lead to any improvement in RBC properties during HIIE in overweight healthy men.

Pathomechanism and optimal renoprotective protocol for remote ischemic preconditioning (RIPC) have not been completely revealed yet.

To investigate micro-rheological effects of early and delayed RIPC in renal ischemia-reperfusion (I/R) in the rat.

In Control group the left femoral artery was cannulated and the left kidney was gently exposed. In the I/R group 45-minute renal ischemia with 120-minute reperfusion period was monitored. In the RIPC groups a 3×10-minute protocol was applied using tourniquet around the right hind-limb 1 hour (RIPC-1) or 24 hours (RIPC-24) prior to the I/R. Blood samples were taken for testing blood gas, acid-base, metabolic and hemorheological parameters.

Lactate and potassium concentration significantly increased in I/R that could be reduced by RIPC, especially in RIPC-24. Creatinine concentration increased further in RIPC groups. I/R and RIPC-1 decreased the pH, RIPC-24 increased. RIPC-24 reduced the drop in base excess. Erythrocyte deformability worsened by renal I/R. In RIPC groups deformability decreased additively. However, RIPC-1 could improve the condition. RIPC-24 showed the highest erythrocyte aggregation values during reperfusion.

Renal I/R worsened metabolic and micro-rheological parameters that could be modulated by RIPC protocols. However, it could not be decided whether the early or the delayed protocol is better.

Objective of the study was to assess the performance of ultrasound strain elastography combined with conventional B-mode ultrasound to diagnose suspicious breast lesions (BI-RADS 4 and 5).

Between January 2015 and December 2017, a total of 86 patients (55±17.9 years) with solid or unclear, non-cystic breast lesions were enrolled in the study. The breast lesions were evaluated by B-mode ultrasound and subsequent ultrasound strain elastography. Ultrasound features including echo pattern, lesion shape, marginal characteristics, calcifications, orientation and posterior features are useful for differentiating benign breast lesions from malignant ones. Malignant ultrasound features are irregular shape, hypoechoic pattern, spiculated margin, nonparallel orientation and posterior shadowing. Lesions with benign features such a circumscribed margin were classified as low conspicuous. In patients with highly conspicuous malignant masses ultrasound-guided core needle biopsy or surgical excision was performed.

Among the 86 patients, 60 masses were histologically proven and 36 of these were malignant. Of the malignant lesions 26 invasive carcinomas were of no special type (NST), 1 invasive lobular carcinoma, 3 ductal carcinomas in situ and 6 metastases. 20 of these patients had breast density classified as ACR 3 or 4. The mean size of the masses was 1.2 cm (range: 0.5–5 cm). Based on ultrasound B-mode imaging, the lesions were classified as BI-RADS category 4 (n = 20; three 4a, nine 4b and eight 4c) and BI-RADS category 5 (n = 16). One patient had to be reclassified after strain elastographxy to BI-RADS 3.

The sensitivity of ultrasound with strain elastography and additional B-Mode ultrasound for the characterization of solid breast lesions was 97%, for conventional B-mode alone 92%; the respective specificities were 82% and 73%, respectively.

Ultrasound elastography can be a supplementary approach to conventional ultrasound to improve the diagnostic accuracy of malignant breast lesions.

To assess the influence of difficult examination conditions onto the diagnostic performance of CEUS (contrast-enhanced ultrasound) in focal liver lesions (FLL).

77 liver CEUS examinations of 75 patients were analysed retrospectively. CEUS was performed as the first diagnostic procedure by one experienced sonographer after bolus injection of 1.0 up to 2.4 ml sulphur hexafluoride microbubbles using a high-end ultrasound device with a high resolution multifrequency probe (1–6 MHz). The combination of complementary imaging (CT or MRI), histology and CEUS follow up of at least 6 months was considered. Cross tables were used to define the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy. Chi-Square Test analysed categorical data.

The patients were between 18 and 84 years old (mean 62±11 years). 26 patients suffered from liver cirrhosis (33.8%). 52 patients (67.5%) received therapy for an oncological disease. The final diagnosis showed 52 malignant FLLs including 24 hepatocellular carcinomas (HCCs), 9 cholangiocellular carcinomas (CCCs) and 19 metastases from different primary tumors. In the other 25 patients no malignant lesions could be detected, three of them presenting however liver haemangioma and two of them liver cysts. The overall lesions’ size according to the CEUS findings ranged from 7 to 100 mm (mean 31.1±22.6 mm). Under good examination conditions the malignant potential of a tumor was diagnosed correctly by CEUS in 98.0% of cases (Sensitivity 97.1%, Specificity 100%, PPV 100%, NPV 94.1%, diagnostic accuracy 98.0%). Limited examination conditions (e.g. obesity, meteorism) were present in 35.1% of cases with a decrease of the diagnostic accuracy to 92.6% (Sensitivity 100%, Specificity 77.8%, PPV 90.0%, NPV 100%).

Despite the influence of difficult examination conditions, CEUS is – in the hands of an experienced sonographer – an excellent diagnostic procedure for the assessment of liver lesions.