Diagnostic criteria for the determination of clinically significant internal carotid artery stenosis using duplex ultrasound.

BACKGROUND: Carotid endarterectomy is beneficial in symptomatic patients with ≥70% stenosis at the bifurcation of the internal carotid artery. The fact that the duplex ultrasound is widely used, inexpensive and non-invasive for examination of the carotid arteries underlines the importance of high accuracy of this method for grading internal artery stenosis. PATIENTS AND METHODS: Duplex scans and arteriograms of carotid arteries of 142 patients were reviewed. Peak and end-diastolic velocities of the common and internal carotid arteries were recorded, and the percent stenosis of the internal carotid artery was determined by arteriogram. Receiver-operator characteristic curves of sensitivity, specificity, positive and negative predictive values and accuracy were determined. RESULTS: The recommended criteria for the detection of ≥70% stenosis of the internal carotid artery were: peak systolic velocity in the internal carotid artery ≥215 cm/s, end-diastolic velocity in the internal carotid artery ≥65 cm/s, ratio of peak systolic velocities in the internal and common carotid arteries ≥2.7 and ratio of the end-diastolic velocities of the internal and common carotid arteries ≥3.7. CONCLUSION: These criteria allow for reliable determination of internal carotid artery stenosis ≥70% by duplex ultrasound.

The effect of renal denervation in an experimental model of chronic renal insufficiency, The REmnant kidney Denervation In Pigs study (REDIP study).

BACKGROUND: Renal denervation (RDN) is a promising therapeutic method in cardiology. Its currently most investigated indication is resistant hypertension. Other potential indications are atrial fibrillation, type 2 diabetes mellitus and chronic renal insufficiency among others. Previous trials showed conflicting but promising results, but the real benefits of RDN are still under investigation. Patients with renal insufficiency and resistant hypertension are proposed to be a good target for this therapy due to excessive activation of renal sympathetic drive. However, only limited number of studies showed benefits for these patients. We hypothesize that in our experimental model of chronic kidney disease (CKD) due to ischemia with increased activity of the renin-angiotensin-aldosterone system (RAAS), renal denervation can have protective effects by slowing or blocking the progression of renal injury. METHODS: An experimental biomodel of chronic renal insufficiency induced by ischemia was developed using selective renal artery embolization (remnant kidney porcine model). 27 biomodels were assessed. Renal denervation was performed in 19 biomodels (denervated group), and the remaining were used as controls (n = 8). The extent of renal injury and reparative process between the two groups were compared and assessed using biochemical parameters and histological findings. RESULTS: Viable remnant kidney biomodels were achieved and maintained in 27 swine. There were no significant differences in biochemical parameters between the two groups at baseline. Histological assessment proved successful RDN procedure in all biomodels in the denervated group. Over the 7-week period, there were significant increases in serum urea, creatinine, and aldosterone concentration in both groups. The difference in urea and creatinine levels were not statistically significant between the two groups. However, the level of aldosterone in the denervated was significantly lower in comparison to the controls. Histological assessment of renal arteries showed that RDN tends to produce more damage to the arterial wall in comparison to vessels in subjects that only underwent RAE. In addition, the morphological damage of kidneys, which was expressed as a ratio of damaged surface (or scar) to the overall surface of kidney, also did not show significant difference between groups. CONCLUSIONS: In this study, we were not able to show significant protective effect of RDN alone on ischemic renal parenchymal damage by either laboratory or histological assessments. However, the change in aldosterone level shows some effect of renal denervation on the RAAS system. We hypothesize that a combined blockade of the RAAS and the sympathetic system could provide more protective effects against acute ischemia. This has to be further investigated in future studies.

Percutaneous Mechanical Thrombectomy Using Rotarex® S Device in Acute Limb Ischemia in Infrainguinal Occlusions.

PURPOSE: To evaluate the effectiveness of percutaneous mechanical thrombectomy using Rotarex S in the treatment of acute limb ischemia (ALI) in infrainguinal occlusions in a retrospective study of patients treated in our institution. METHODS: In this study, we identified a total of 147 ALI patients that underwent mechanical thrombectomy using Rotarex S at our institution. In 82% of the cases, percutaneous thrombectomy was used as first-line treatment, and for the remainder of the cases, it was used as bailout after ineffective aspiration or thrombolysis. Additional fibrinolysis and adjunctive aspirational thrombectomy were utilized for outflow occlusion when required. Procedural outcomes, amputation rate, and mortality at 30 days were evaluated. RESULTS: Of the 147 patients treated with mechanical thrombectomy, Rotarex S was used as first-line treatment in 120 cases and as second-line treatment in 27 cases. Overall, we achieved 90.5% procedural revascularization success rate when combining mechanical thrombectomy with limited thrombolysis for severe outflow obstruction, and 1 death and 3 amputations were observed. We achieved primary success in 68.7% of the patients with the mechanical thrombectomy only, and in 21.8% of the patients, we successfully used additional limited thrombolysis in the outflow. The overall mortality was 0.7% and amputation rate was 2% at 30 days. CONCLUSION: Percutaneous mechanical thrombectomy as first-line mini-invasive treatment in infrainguinal ALI is safe, quick, and effective, and the performance outcomes can be superior to that of traditional surgical embolectomy.

[A rare case of mobile atherosclerotic plaque with a high embolic potential in the femoral artery]. / Vzácný prípad mobilního aterosklerotického plátu ve femorální tepne s vysokým embolizacním potenciálem.

Atherosclerosis is a diffuse disease which may lead to the development of unstable atherosclerotic plaque. Its rupture can result in acute ischemic event. The atherosclerotic plaques with a mobile component are typical presentations of such instability and patients with these plaques are at high risk of acute ischemic events. In the current literature, substantial data regarding the mobile atherosclerotic plaques in carotid arteries and thoracic aorta is published. However there are almost no data concerning the mobile plaques in the peripheral arteries of the lower limbs. We present a rare case of a patient with generalized atherosclerosis, in whom an asymptomatic mobile atherosclerotic plaque in the common femoral artery with a high embolic potential was diagnosed. This plaque was successfully removed by femoral endarterectomy. On the basis of this case, we review the possibilities and limitations of the current imaging methods in detection of mobile plaques in the peripheral arteries. Moreover optimal therapeutic approaches in such patients are discussed.

Renal denervation decreases effective refractory period but not inducibility of ventricular fibrillation in a healthy porcine biomodel: a case control study.

BACKGROUND: Ventricular arrhythmias play an important role in cardiovascular mortality especially in patients with impaired cardiac and autonomic function. The aim of this experimental study was to determine, if renal denervation (RDN) could decrease the inducibility of ventricular fibrillation (VF) in a healthy porcine biomodel. METHODS: Controlled electrophysiological study was performed in 6 biomodels 40 days after RDN (RDN group) and in 6 healthy animals (control group). The inducibility of VF was tested by programmed ventricular stimulation from the apex of right ventricle (8 basal stimuli coupled with up to 4 extrastimuli) always three times in each biomodel using peripheral extracorporeal oxygenation for hemodynamic support. Further, basal heart rate (HR), PQ and QT intervals and effective refractory period of ventricles (ERP) were measured. Technical success of RDN was evaluated by histological examination. RESULTS: According to histological findings, RDN procedure was successfully performed in all biomodels. Comparing the groups, basal HR was lower in RDN group: 79 (IQR 58; 88) vs. 93 (72; 95) beats per minute (p = 0.003); PQ interval was longer in RDN group: 145 (133; 153) vs. 115 (113; 120) ms (p < 0.0001) and QTc intervals were comparable: 402 (382; 422) ms in RDN vs. 386 (356; 437) ms in control group (p = 0.1). ERP was prolonged significantly in RDN group: 159 (150; 169) vs. 140 (133; 150) ms (p = 0.001), but VF inducibility was the same (18/18 vs. 18/18 attempts). CONCLUSIONS: RDN decreased the influence of sympathetic nerve system on the heart conduction system in healthy porcine biomodel. However, the electrophysiological study was not associated with a decrease of VF inducibility after RDN.

[Deep calf vein thrombosis]. / Flebotrombóza lýtkových zil.

Isolated calf vein thrombosis in the population of patients with deep vein thrombosis is found approximately in 10 to 25 % of cases. We present 3 cases of calf vein thrombosis which occurred due to unusual causes. Specific characteristics of this form of thromboembolic disease are discussed and compared to proximal deep vein thrombosis with emphasis to symptoms, risk of complications, prognosis and therapeutic approach.