Closure of Post-thrombotic Iliac Arteriovenous Fistulas by Iliac Vein Recanalization

PURPOSE

The purpose of this study was to report the closure of iliac arteriovenous fistulas associated with a post-thrombotic iliac vein occlusion by iliac venous stent recanalization.

CASE REPORT

An 80-year-old woman presented with a worsening painful swelling of her left leg after an iliofemoral deep vein thrombosis 6 months ago. Duplex ultrasound and magnetic resonance venography revealed a post-thrombotic obstruction of her iliac veins as well as several arteriovenous fistulas between branches of her left external and internal iliac arteries and adjacent diseased venous segments. In a first attempt, coil embolization did not sustainably close these iliac arteriovenous fistulas. Direct stent recanalization of the chronically diseased iliofemoral venous segment, however, resulted in an immediate closure of arteriovenous shunt flow and subsequent improvement of clinical symptoms. Six months after iliac vein stent recanalization, still no fistulas could be detected any more, venous stents were fully patent, and the patient was free of symptoms.

CONCLUSION

Post-thrombotic iliofemoral obstructions might be associated with the development of arteriovenous fistulas. Direct stent recanalization of the chronically occluded veins results in closure of related arteriovenous fistulas.

CLINICAL IMPACT

This case suggests that the combined occurrence of post-thrombotic venous obstructions with arteriovenous fistulas, which are related to aforementioned venous lesions, should be evaluated for primary venous stent recanalization rather than fistula embolization.

Preprocedural imaging modalities in patients undergoing iliocaval venous recanalization and stent placement

PURPOSE

To determine the diagnostic accuracy of preinterventional imaging modalities in patients being evaluated for iliocaval venous recanalization and stent placement.

METHODS

Consecutive patients with iliocaval postthrombotic obstructions or nonthrombotic iliac vein lesions (NIVL), who were scheduled for recanalization, underwent duplex ultrasound (DUS), magnetic resonance venography (MRV), multiplanar venography (MPV), and intravascular ultrasound (IVUS). The diagnostic accuracies of DUS, MRV, and MPV were analyzed using IVUS as reference.

RESULTS

A total of 216 limbs in 108 patients (80 patients with postthrombotic obstructions, 28 patients with NIVL) were examined. In patients with postthrombotic obstructions, the diagnostic sensitivities for the detection of lesions of the common femoral vein were 81% (95% CI 71-89%) for DUS, 76% (95% CI 65-85%) for MRV, and 86% (95% CI 76-93%) for MPV. The sensitivities for detecting lesions of the iliac veins were 96% (95% CI 89-99%) for DUS, 99% (95% CI 92-100%) for MRV, and 100% (95% CI 94-100%) for MPV. Regarding the inferior vena cava, the sensitivities were 44% (95% CI 24-65%) for DUS, 52% (95% CI 31-73%) for MRV, and 70% (95% CI 47-86%) for MPV. The sensitivities for detecting NIVL were 58% (95% CI 34-79%) for DUS, 90% (95% CI 68-97%) for MRV, and 95% (95% CI 73-99%) for MPV.

CONCLUSION

In patients scheduled for recanalization of iliocaval postthrombotic obstructions, the sensitivities of DUS, MRV, and MPV were similar. In patients with suspected inferior vena cava involvement and in patients with NIVL, additional imaging with MR or conventional venography is required.

Vascular access for lipid apheresis: a challenge in young children with homozygous familial hypercholesterolemia

Background

Homozygous familial hypercholesterolemia (hoFH) is a rare genetic disorder leading to extremely increased LDL-cholesterol (LDL-C), resulting in high cardiovascular risk in early childhood. Lipid apheresis (LA) is an effective treatment and should be started as early as possible to prevent premature cardiovascular events. As peripheral punctures in children can be challenging due to small vessels and anxiety, this study aimed to evaluate feasibility and safety of central venous catheters (CVCs) as vascular access for LA in young children with hoFH.

Methods

Retrospective analysis (2016-2019) on four children with hoFH aged 3-5 years, performing weekly or biweekly LA with a CVC.

Results

LDL-C decreased by> 60%. In three children, the use of a permanent CVC for 698, 595, and 411 days, respectively, avoided difficult peripheral access, without the occurrence of occlusion or thrombosis. Unfortunately, one child had recurrent CVC-related infections and needed an arteriovenous fistula from the age of 5. Although the mean dwell time per catheter was 212 days, there were, as expected, severe side effects of early catheter infections with sepsis and accidental self-removal. Starting LA at an early age improved or stabilized carotid intima-media thickness (IMT) in three children. However, IMT did increase in one child caused by intolerance to peripheral punctures and LA interruption.

Conclusions

Permanent CVCs are a viable temporary access choice for LA in young children with hoFH until peripheral venipuncture is practicable. The risk of CVC-related infections needs to be taken into account.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03192-7.

A Real World 10-Year Experience With Vascular Closure Devices and Large-Bore Access in Patients Undergoing Transfemoral Transcatheter Aortic Valve Implantation

Transcatheter aortic valve replacement (TAVR) has established itself as a safe and efficient treatment option in patients with severe aortic valve stenosis, regardless of the underlying surgical risk. Widespread adoption of transfemoral procedures led to more patients than ever being eligible for TAVR. This increase in procedural volumes has also stimulated the use of vascular closure devices (VCDs) for improved access site management. In a single-center examination, we investigated 871 patients that underwent transfemoral TAVR from 2010 to 2020 and assessed vascular complications according to the Valve Academic Research Consortium (VARC) III recommendations. Patients were grouped by the VCD and both, vascular closure success and need for intervention were analyzed. In case of a vascular complication, the type of intervention was investigated for all VCDs. The Proglide VCD was the most frequently used device (n = 670), followed by the Prostar device (n = 112). Patients were old (median age 83 years) and patients suffered from high comorbidity burden (60% coronary artery disease, 30% type II diabetes, 40% atrial fibrillation). The overall rate of major complications amounted to 4.6%, it was highest in the Prostar group (9.6%) and lowest in the Manta VCD group (1.1% p = 0.019). The most frequent vascular complications were bleeding and hematoma (n = 110, 13%). In case a complication occurred, 72% of patients did not need any further intervention other than manual compression or pressure bandages. The rate of surgical intervention after complication was highest in the Prostar group (n = 15, 29%, p = 0.001). Temporal trends in VCD usage highlight the rapid adoption of the Proglide system after introduction at our institution. In recent years VCD alternatives, utilizing other closure techniques, such as the Manta device emerged and increased vascular access site management options. This 10-year single-center experience demonstrates high success rates for all VCDs. Despite successful closure, a significant number of patients does experience minor vascular complications, in particular bleeding and hematoma. However, most complications do not require surgical or endovascular intervention. Temporal trends display a marked increase in TAVR procedures and highlight the need for more refined vascular access management strategies.

Micro- and macrovascular function in patients suffering from primary adrenal insufficiency: a cross-sectional case-control study

BACKGROUND

Despite adequate glucocorticoid (GC) and mineralocorticoid (MC) replacement therapy, patients suffering from primary adrenal insufficiency (AI) have an increased mortality, mainly due to cardiovascular diseases. Only little knowledge exists on the contribution of MC substitution to the cardiovascular risk. Therefore, this study investigates the impact of plasma renin concentration on parameters of micro- and macrovascular function.

METHODS

26 patients with primary AI [female = 18, age: 51 (28; 78) years; BMI: 24 (18; 40) kg/m²; disease duration: 18 (5; 36) years] were included in this cross-sectional analysis. Intima media thickness (IMT) and pulse wave velocity (PWV) were investigated to assess macrovascular remodeling and arterial stiffness. Microvascular function was estimated by post-occlusive reactive hyperemia using laser Doppler fluxmetry. Baseline perfusion, biological zero, peak perfusion, time to peak and recovery time were recorded. Patients were grouped according to their median plasma renin concentration of previous visits (Renin_high vs Renin_low) and were compared to a group of healthy women [age: 44 (43; 46) years; BMI: 24.2 (21.8; 27.5)].

RESULTS

PWV was significantly higher in AI patients compared to controls [9.9 (5; 18.5) vs 7.3 (6.8; 7.7) m/s; p < .01], whereas no differences in microvascular function could be found. In Renin_low time to peak perfusion was significantly longer [6.0 (3; 15) vs 3.5 (1.5; 11) s; p < .05], whereas no differences in IMT and PWV were observed between Renin_high and Renin_low. No impact of GC dose was observed.

CONCLUSIONS

Microvascular function is not impaired in patients with primary AI under adequate replacement therapy, although higher renin concentrations are associated with subclinical improvements. No relation between RAAS activity and macrovascular function is observed, while arterial stiffness might be increased in primary AI.

Thromboangiitis Obliterans Biomarker Shifts in Different Acute Phase Stages: A Case Study

Thromboangiitis obliterans (TAO) is a rare vasculopathy that is predominantly seen in young male smokers. Recently, new biomarkers have been shown to be useful in distinguishing TAO from acute phase TAO in an Asian study population. The present case study illustrates their application in a European patient during TAO exacerbation and their association with therapeutic performance.

Drug coated balloons in the superficial femoral artery

Despite the progress in endovascular treatment of patients with peripheral arterial disease, restenosis remains the major drawback, especially in patients with femoropopliteal lesions. To reduce neointimal proliferation and subsequent restenosis the use of antiproliferative drug eluting devices was implemented in the endovascular treatment of femoropopliteal disease. Aiming to use the favorable effects of these antiproliferative agents and to reduce foreign body exposure in affected arteries, drug coated balloons (DCB) have been developed. Up to now, several randomized controlled trials have consistently demonstrated the superiority of DCB over uncoated balloon angioplasty in the treatment of femoropopliteal lesions. Similarly, DCB appear to have favorable effects on vessel patency in the treatment of femoropopliteal in-stent restenosis. However, there still is a need for further studies, especially addressing different lesion characteristics as well as the combinations of particular treatment modalities.

Speckle-Tracking-Based Evaluation of Vascular Strain at Different Sites of the Arterial Tree in Healthy Adults

Purpose: Vascular ultrasound (US) allows the analysis of vascular strain by speckle-tracking. This study sought to assess the extent to which vas cular strain varies between different segments of the arterial tree. Furthermore, this study aimed to investigate the reproducibility of vascular strain determination as well as of the components that contribute to the variance of vascular strain measurements in different vascular beds. Materials and Methods: Speckle-tracking was used to determine the vascular strain of the abdominal aorta (AA), the common carotid artery (CCA), the common femoral (CFA) and the popliteal artery (PA) of healthy adults. Intra- and interday reproducibility and the components of variance of vascular strain of the respective arteries were determined. Results: A total of 589 US clips obtained in 10 healthy adults (7 males, 28.3 ± 3.2 years) were analyzable. Vascular strain was 7.2 ± 3.0 % in the AA, 5.7 ± 2.1 % in the CCA, 2.1 ± 1.1 % in the CFA and 1.9 ± 1.1 % in the PA. The intraday coefficients of variation of vascular strain were 6.2 % (AA), 3.9 % (CCA), 3.3 % (CFA) and 6.1 % (PA), and the interday coefficients of variation were 5.9 % (AA), 8.4 % (CCA), 10 % (CFA) and 4.6 % (PA). The variance of vascular strain mainly depended on the investigated vessel and subject. Individual DUS clips, the day of examination and the (right/left) body side (in paired arteries) had no impact on the variance of vascular strain. Conclusion: Vascular strain substantially varies between different sites of the arterial tree. Speckle-tracking by DUS allows the reliable determination of vascular strain at different arterial sites.

Impact of age and gender on microvascular function

BACKGROUND

Microcirculatory function can be assessed by postocclusive reactive hyperaemia (PORH) using laser Doppler fluxmetry. Previous studies have shown that PORH reveals microvascular damage at an early stage. In particular, at younger ages, PORH might depend on age and gender. To implement PORH into a larger scale of clinical studies, one has to be aware of the influence of age and gender on microcirculation. The aim of this study was to assess the impact of age and gender on microcirculatory function during adolescence.

MATERIALS AND METHODS

Within the scope of an epidemiological project, 896 children and adolescents underwent assessment of PORH by laser Doppler fluxmetry. Microcirculatory parameters during PORH (baseline perfusion, biological zero, peak perfusion, time to peak perfusion and recovery time) were analysed in relation to age (by tertiles) and gender.

RESULTS

Baseline perfusion, biological zero and peak perfusion were lower in children/adolescents in the upper age tertile (12·3-18·1 years) than in the middle (9·8-12·2 years) and lower (4·3-9·7 years) age tertiles (P < 0·0001). In the total of participants, baseline perfusion, biological zero and peak perfusion were higher in males than in females (P < 0·0001). Analysing microcirculatory parameters as a function of age and gender, the sex differences were only apparent in the upper and the middle age tertiles, but not in the lower.

CONCLUSIONS

During adolescence, PORH is a function of age. At higher age, microvascular reactivity considerably depends on gender, whereas no sex differences are present at younger ages.

Transcutaneous oxygen tension monitoring in critically ill patients receiving packed red blood cells

PURPOSE

Whether transfusions of packed red blood cells (PRBCs) affect tissue oxygenation in stable critically ill patients is still matter of discussion. The microvascular capacity for tissue oxygenation can be determined noninvasively by measuring transcutaneous oxygen tension (tcpO2). The aim of this study was to assess tissue oxygenation by measuring tcpO2 in stable critically ill patients receiving PRBC transfusions.

METHODS

Nineteen stable critically ill patients, who received 2 units of PRBC, were prospectively included into this pilot study. Transcutaneous oxygen tension was measured continuously during PRBC transfusions using Clark's electrodes. In addition, whole blood viscosity and global hemodynamics were determined.

RESULTS

Reliable measurement signals during continuous tcpO2 monitoring were observed in 17 of 19 included patients. Transcutaneous oxygen tension was related to the global oxygen consumption (r=-0.78; P=.003), the arterio-venous oxygen content difference (r=-0.65; P=.005), and the extraction rate (r=-0.71; P=.02). The transfusion-induced increase of the hemoglobin concentration was paralleled by an increase of the whole blood viscosity (P<.001). Microvascular tissue oxygenation by means of tcpO2 was not affected by PRBC transfusions (P=.46). Packed red blood cell transfusions resulted in an increase of global oxygen delivery (P=.02) and central venous oxygen saturation (P=.01), whereas oxygen consumption remained unchanged (P=.72).

CONCLUSIONS

In stable critically ill patients, microvascular tissue oxygenation can be continuously monitored by Clark's tcpO2 electrodes. According to continuous tcpO2 measurements, the microvascular tissue oxygenation is not affected by PRBC transfusions.

Familial hypercholesterolemia affects microvascular autoregulation in children

OBJECTIVE

Familial hypercholesterolemia (FH) impairs macrovascular endothelial function in childhood and causes an increase of cardiovascular risk in later life. Whether microvascular function is affected in children with FH is unknown. The aim of this study was to investigate the impact of FH on microvascular autoregulation in children by post occlusive reactive hyperemia (PORH).

METHODS

PORH of the skin was assessed using laser Doppler fluxmetry. Baseline perfusion, biological zero, defined as no-flow laser Doppler signal during suprasystolic occlusion, peak perfusion after release of suprasystolic occlusion, as well as time to peak perfusion and recovery time, defined as time until baseline perfusion is resumed, were measured in 16 children, who were diagnosed with FH according to current guidelines, and in 91 healthy controls.

RESULTS

In children with FH, peak perfusion was higher (FH: 1.60±0.68 vs. controls: 1.26±0.50 AU [arbitrary units], p=0.02), recovery time was longer (110±42.61 vs. 83.18±35.08 s, p=0.01) and biological zero was lower than in controls (0.12±0.04 vs. 0.18±0.05 AU, p<0.001). Baseline perfusion and time to peak were not different between children with FH and controls (baseline perfusion: 0.43±0.21 vs. 0.38±0.15 AU, p=0.18; time to peak: 15.44±12.25 vs. 18.18±17.79 s, p=0.56).

CONCLUSION

For the first time the present study reveals an impact of FH on microvascular autoregulation in children: the differences of PORH between children with FH and controls indicate an affected autoregulation of microvascular blood flow in FH, which has its onset in childhood.

Poor agreement in carotid artery stenosis detection by ultrasound between external offices and a vascular center

BACKGROUND

Carotid duplex ultrasonography is the prime investigation used to grade carotid artery stenosis in clinical routine. We compared the carotid ultrasound (US) scans performed externally with our results.

MATERIALS AND METHODS

This retrospective study included 288 patients who had been referred to our outpatient department and initially presented with an external carotid duplex scan report indicating carotid atherosclerosis. The external scans were analyzed and compared with our scans in respect of the accuracy of identification and quantification of stenosis, the criteria used to grade stenosis and the duplex criteria used. Weighted Kappa coefficients (K) were computed to quantify the agreement between internal and external findings.

RESULTS

The majority of the external reports had been performed by radiologists [70.8 % (n = 204)], followed by specialists of internal medicine [19.4 (n = 56)] and by neurologists [9.8 % (n = 28)]. Only slight agreement was registered between the external reports and those performed at our institution with regard to the identification of stenosis (K = 0.2 for the left and K = 0.12 for the right side). Greater agreement was observed in respect of the level of stenosis (K = 0.42 for the right and K = 0.54 for the left side). Overestimation of the level of stenosis was registered for 45 % in the left internal carotid artery (ICA) and 36 % in the right ICA; the overestimation was most pronounced for occlusions and high-grade stenoses, which is a source of great concern for decision-making.

CONCLUSIONS

The present data indicate only a slight agreement between carotid duplex US imaging performed at medical offices and our results.

Microvascular autoregulation in children and adolescents with type 1 diabetes mellitus

AIMS/HYPOTHESIS

Deterioration of microvascular function may have an early onset in individuals with type 1 diabetes mellitus. We hypothesised that microvascular autoregulation is impaired in children with type 1 diabetes and can be detected non-invasively by postocclusive reactive hyperaemia (PORH).

METHODS

Microvascular autoregulation was assessed in 58 children with type 1 diabetes and 58 age- and sex-matched healthy controls by PORH using laser Doppler fluxmetry. Baseline perfusion, biological zero (defined as a 'no flow' laser Doppler signal during suprasystolic occlusion), peak perfusion following occlusion, time to peak and recovery time (time until baseline perfusion is resumed) were recorded and compared between the groups.

RESULTS

Peak perfusion was higher in children with type 1 diabetes than in healthy controls (1.7 ± 0.93 AU [arbitrary units] vs 1.29 ± 0.46 AU; p = 0.004), and biological zero was lower in children with type 1 diabetes vs controls (0.14 ± 0.04 AU vs 0.19 ± 0.04 AU; p < 0.0001). No differences were seen between the groups in baseline perfusion, time to peak during PORH and recovery time following PORH.

CONCLUSIONS/INTERPRETATION

PORH reveals impaired microvascular autoregulation in children with type 1 diabetes. The higher peak perfusion might reflect a decline in the vasoconstrictive ability of arteriolar smooth muscle cells upstream of capillary beds in children with type 1 diabetes.

Microvascular function is impaired in children with morbid obesity

Children’s obesity is a growing problem in Western societies. We hypothesized that morbid obesity (body mass index [BMI] > 99.5th percentile) might affect microvascular function at an early stage. Therefore, we assessed the microvascular function of 41 obese children (13.2 ± 2.8 years, BMI 32.9 ± 6.6) in comparison to 91 healthy controls (12.7 ± 2.1 years, BMI 18.2 ± 2.5) by post-occlusive reactive hyperemia measured by a laser Doppler: baseline perfusion, biological zero (defined as ‘no-flow’ laser Doppler signal during suprasystolic occlusion), peak perfusion (following occlusion), time to peak perfusion and recovery time (time until resuming baseline perfusion) were recorded and compared between both groups. Peak perfusion was higher in children with morbid obesity than in controls (1.67 ± 0.76 AU [arbitrary units] vs 1.26 ± 0.5 AU, p < 0.001). Consecutively, recovery time was longer in children with morbid obesity (118.21 ± 34.64 seconds) than in healthy children (83.18 ± 35.08 seconds, p < 0.001). In conclusion, higher peak perfusion and prolonged recovery time in children with morbid obesity seem to reflect microvascular dysfunction due to an impaired vasoconstrictive ability of precapillary sphincters.

Impact of international guidelines on the management of cardiovascular risk factors in diabetic patients with peripheral arterial disease

AIM

Recent data on the management of cardiovascular risk factors in high risk patients showed that dyslipidemia is still treated in an inadequate way, especially in diabetic patients. We wanted to analyze the impact of the recommendation of the Inter-Society Consensus for the management of PAD (TASC-II) on the actual situation.

METHODS

In this retrospective cohort study we analyzed total-, HDL-, LDL-cholesterol, triglycerides and blood glucose using capillary blood in diabetic patients, admitted to our outpatient department. Besides the recording of a complete medical history and vascular risk factors, an ABI-measurement and a carotid Duplex ultrasonography were performed at presentation.

RESULTS

We studied 111 diabetic patients (44 female and 67 male) with a mean age (+/-SD) of 70, 3 (+/-9, 9) years; a BMI of 28, 2 (+/-4, 2) and a mean waist circumference of 103 (+/-12, 2) cm. Metabolic syndrome according to the NCEP-ATP-III criteria (2001) was shown in 86% (N.=95). 41% (N.=45) had clinically manifest vascular disease in a second and 23% (N.=26) even in a third vascular territory. Total-cholesterol was 183+/-43 mg/dL; LDL-C 94 +/-30 mg/dL; HDL-cholesterol 44 +/-12 mg/dl and triglycerides 219+/-103 mg/dL. A total of 33% (N.=37) in this high risk cohort attained the LDL-C target levels according to the TASC-II guidelines. A total of 68% (N.=76) was on a HMG-CoA-reductase-inhibitor, 61% (N.=68) had platelet aggregation inhibitors.

CONCLUSIONS

We found poor adherence to international guidelines for secondary prevention in diabetic patients with PAD in this outpatient setting.

Cerebral microembolism during transcatheter closure of patent foramen ovale

BACKGROUND

Although transcatheter closure of patent foramen ovale (PFO) and atrial septal defect (ASD) has become a commonly performed intervention, the incidence of cerebral embolism with or without neurological deficits during such procedures has not been studied.

METHODS

We monitored the middle cerebral artery in two different depths (48 mm and 53 mm) by continuous transcranial Doppler ultrasound during transcatheter PFO closure in 35 consecutive patients (F/M 20/15, mean age 47 +/- 11 years) and during ASD closure in 8 patients (F/M 7/1, mean age 45 +/- 5 years). All automatically detected high intensity transient signals (HITS) were manually reviewed to eliminate artifacts.

RESULTS

HITS were detected in 33 of 35 patients (96%) with a median rate of 8 (interquartile range 4-19, range 2-29) HITS. The highest rates were observed when the septum was crossed with the guide wire (median 2; IQR 0-12; range 0-25) and when the left atrial disc was deployed (median 2; IQR 1-4; range 0-13). Despite this high rate of cerebral microembolism no clinically apparent neurological or neuropsychological deficit was observed.

CONCLUSIONS

Silent cerebral embolism frequently occurs during transcatheter PFO and ASD closure. The peak of HITS at the time of crossing the septum with the guide wire may support the hypothesis that cerebral emboli in patients with PFO may originate from the septum itself. This may represent an alternative mechanism to the generally assumed paradoxical embolism.

Arterial remodeling and hemodynamics in carotid stents: a prospective duplex ultrasound study over 2 years

OBJECTIVE

This study was undertaken to study negative and positive arterial remodeling processes within self-expanding carotid stents, their interaction, and the resulting changes in hemodynamics over 2 years, with duplex ultrasound scanning.

SUBJECTS AND METHODS

One hundred twelve consecutive patients with 121 successfully stented carotid arteries were examined with color-coded duplex ultrasound scanning the day after the stent procedure and at 3, 6, 12, and 24 months of follow-up. The stent diameters at the proximal, middle, and distal regions, and the maximal neointimal thickness (B-mode) and hemodynamic parameters were recorded. Pre-interventional plaques were assigned to three types: soft, fibrous, and largely calcified.

RESULTS

The diameters of the self-expanding stents steadily increased over 2 years (positive arterial remodeling), from (mean +/- SD) 5.80 +/- 0.89 mm to 6.77 +/- 0.98 mm in the proximal stent area, from 3.51 +/- 0.76 mm to 4.92 +/- 0.89 mm in the middle stent area, and from 3.7 +/- 0.5 mm to 4.68 +/- 0.61 mm in the distal stent area (P<.001). Stent expansion was most marked in the middle stent area, depending on the type of pre-interventional plaque. The extent in stent expansion was more in soft than in fibrous and calcified plaques (P<.001). Neointimal thickness increased up to 12 months, and stabilized thereafter. The mean (+/- SD) neointimal thickness at 3, 6, 12, and 24 months was 0.61 +/- 0.28 mm, 0.97 +/- 0.39 mm, 1.06 +/- 0.36 mm, and 1.12 +/- 0.38 mm, respectively. These complex interactions resulted in the dominance of negative remodeling secondary to neointimal proliferation, with an increased flow ratio during the first year, from 1.16 +/- 0.37 at day 1 to 1.23 +/- 0.46 at 3 months, 1.67 +/- 1.37 at 6 months, and 1.57 +/- 0.70 at 12 months (P<.001), followed by a tendency to decrease as a result of stent expansion thereafter (flow ratio at 24 months, 1.49 +/- 0.70). Two of 121 stents (1.6%) had recurrent stenosis that required a secondary procedure.

CONCLUSIONS

Neointimal proliferation or negative arterial remodeling prevails up to 12 months, and may give rise to rare stent recurrent stenosis. Stent expansion reduces this effect in the first year, and dominates in the second year. This might contribute to the good mid-term outcome of carotid stenting. Poor stent expansion in heavily calcified plaques calls for primary surgical management.

Neointimal proliferation within carotid stents is more pronounced in diabetic patients with initial poor glycaemic state

AIMS/HYPOTHESIS

We studied the influence of initial hyperglycaemia on neointimal proliferation within carotid Wallstents.

METHODS

A total of 112 patients were followed by duplex sonography after carotid stenting for 24 months. Patients were assigned to three groups: non-diabetic subjects (group A) and diabetic patients, who were assigned according to their baseline HbA(1)c values, to group B1(HbA(1)c<or=6.5%) or group B2 (HbA(1)c>6.5%).

RESULTS

At baseline the groups did not differ with respect to other vascular risk factors and residual stenosis on angiograms. The maximal thickness of the layer between the stent and the perfused lumen was measured at the duplex follow-ups. At 3 months the typical ultrasonic structure of the neointima was clearly discernible. From this point on, group B2 differed significantly ( p<0.001) compared with B1 and A with respect to the maximal thickness of neointima and the time course of its ingrowth: group A vs B1 vs B2 was 0.51+/-0.39 vs 0.52+/-0.33 vs 0.56+/-0.35 at 3 months, 0.91+/-0.27 vs 0.90+/-0.38 vs 1.14+/-0.48 at 6 months, 1.02+/-0.24 vs 0.97+/-0.34 vs 1.21+/-0.44 at 12 months and 1.09+/-0.23 vs 1.10+/-0.31 vs 1.23+/-0.37 at 24 months.

CONCLUSION/INTERPRETATION

Initial hyperglycaemia seems to be a predictor of more pronounced neointimal proliferation after carotid stenting independent of diabetes. As intimal hyperplasia is known to be responsible for stent restenosis, strict optimisation of the hyperglycaemic state should be aimed at before elective carotid artery stenting.

Effect of carotid artery stenting on the external carotid artery

OBJECTIVE

We studied the fate of the ipsilateral external carotid artery (ECA) after stenting of the internal carotid artery (ICA) compared with the contralateral ECA.

SUBJECTS AND METHODS

One hundred twenty-one ipsilateral ECAs in 112 consecutive patients who underwent carotid artery Wallstent placement were prospectively studied with color-coded duplex sonographic scanning (CCDS) and compared with 83 contralateral ECAs over 2 years. CCDS was scheduled for the day before (day 0), the day after (day 1) and 3, 6, 12, and 24 months after stenting. Development of ECA occlusive disease was evaluated with ECA-common carotid artery flow ratio (peak systolic velocity). For estimation of ECA stenosis 70% or greater, flow ratio 4.1 was used as the cutoff point.

RESULTS

Before and after stenting, two and three (one additional) ECA occlusions were seen. Median grade of ECA stenosis on day 1 did not significantly change at angiography (P = 1.0; tendency of increase) or CCDS (P =.27; tendency of decrease).At follow-up (day 1-24 months, CCDS only), frequency of stenosis 70% or greater in the ipsilateral ECA was 21 of 120 (17.5%) on day 1 and 41 of 107 (38.32%) at 24 months, and 3 of 107 (2.5%) and 5 of 107 (4.67%) ECA occlusions were registered at the two time points. Progression of disease, as demonstrated by increase in flow ratio over time, was much more pronounced in the ipsilateral ECAs compared with the contralateral ECAs (P =.0002). In stented ICA, 2 (1.85%) asymptomatic recurrent stenoses 70% or greater were found at CCDS. One of three patients with new ECA occlusions reported jaw claudication for 10 days. Perioperative stroke (one major, four minor) occurred in 5 of 121 patients (4.46%). Two minor strokes caused by embolization occurred during the first year.

CONCLUSION

The more pronounced progression of arteriosclerotic disease at the orifice of the ipsilateral ECAs during the first year after carotid stenting might be due to local factors of the ICA stent. Its clinical significance in respect to the effect of the ECA as collateral supply to the brain might depend on the incidence of carotid stent rerecurrent stenosis, which was low in the present study.

Healing of carotid stents: a prospective duplex ultrasound study

PURPOSE

To study the dynamics of carotid stent healing over a 2-year period using duplex ultrasound imaging.

METHODS

One hundred twelve patients with 121 successfully stented carotid arteries were examined with color-coded duplex ultrasound the day after the stent procedure and at 1, 3, 6, 12, and 24 months in follow-up. The maximal thickness and echogenicity of the layer between the stent and the perfused lumen (SPL) were evaluated. Echogenicity was classified as echogenic if the SPL layer was clearly detected in B mode and echolucent if the SPL layer was barely visible in B mode, its border defined by assistance of color-coded flow.

RESULTS

At day 1, an echolucent SPL layer with a median thickness of 0.7 mm was interpreted as a thrombotic layer, which decreased at 1 month to practically zero (i.e., not detectable). In follow-up, increases in thickness (mainly up to 6 months) and echogenicity (up to 12 months) of the SPL layer were interpreted as neointimal ingrowth. At 3, 6, and 12 months, the median maximal thickness of the SPL layer was 0.5 mm, 0.9 mm, and 1.0 mm, respectively, whereas the percentage of patients with an echogenic SPL layer was 27% (32/119), 56% (66/117), and 95% (105/110), respectively, at the same time intervals. No further change was observed at the 24-month examination.

CONCLUSIONS

Three phases of carotid stent incorporation are defined: (1) an early unstable period soon after stent placement with an echolucent (thrombotic) SPL layer, (2) a moderately unstable phase with ingrowing neointima (1-12 months), and (3) a stable phase from the second year on. These data may indicate the need for different intensities of therapy and surveillance intervals.

Single-center experience with carotid stent restenosis

PURPOSE

To report the angiographic morphology of carotid stent restenosis and the possible therapies based on data from a single-center experience.

METHODS

In a 45-month period, 279 patients (196 men; mean age 70 +/- 9 years, range 50-89) underwent successful Wallstent placement in 303 stenotic internal carotid arteries (ICA). Patients were followed with duplex sonography; angiography was used to confirm any significant (> or =70%) recurrent lesions detected on the ultrasound scan. Further balloon dilation with or without stent placement was undertaken. RESULTS; Over a median 12-month follow-up (interquartile range 6-24), there were 9 (3.0%) carotid stent restenoses found, all within 12 months after stent placement. Two types of restenosis were differentiated. In the more common form, "in-stent" stenoses (n = 6) were detected and treated with stent placement; lasting success (patency >12 months after retreatment) was achieved in 4. Early second and third recurrences arose in the other 2 stents within 3 months of the first retreatment; additional stents were placed at each recurrence. Both patients suffered a major cerebral event after 17 months. Less often, an "end of stent" stenosis (n = 3) developed at a kink in the ICA adjacent to the cephalad end of the stent. Lasting success was achieved by balloon dilation without additional stent placement in all 3 cases. No procedure-related complications were observed within 30 days after any treatment for restenosis.

CONCLUSIONS

Carotid stent restenosis, which occurs rarely after 1 year, can be treated safely by further percutaneous interventions.