Healing process of venous ulcers: the role of microcirculation

In order to describe adequately the process of healing in the intermediate degrees, we investigated microcirculatory changes in the venous ulcers at well-defined stages of wound repair. We investigated dynamic changes in microcirculation during the healing process of venous ulcers. Ten venous ulcers were investigated in three consecutive clinical stages of wound healing: non granulation tissue (NGTA), GTA and scar. Subpapillary microcirculation was measured by laser Doppler perfusion (LDP) imaging and expressed using LDP values in arbitrary units. Nutritive perfusion by capillary microscopy and expressed as capillary density (CD) - the number of capillaries per square millimetre. Before the development of GTA the LDP was low (median 1·35; lower-upper quartiles 0·71-1·83) accompanied with zero CD in all but one patient who had a density of 1. With the first appearance of GTA in the same area, the LDP was improved (2·22; 1·12-2·33; P = 0·0024) when compared with NGTA, in combination with a significant increase in CD (1·75; 0-3; P = 0·0054). In scar, the LDP was similar to that in the NGTA (1·03; 0·77-1·83; P = 0·278), combined with the highest CD (5·75; 4·5-8) in comparison with the previous stages of the area (for both pairs, P < 0·0001). Venous ulcers are caused by poor nutritive and subpapillary perfusion. Subpapillary perfusion plays a major role in the formation of GTA. In a scar, the increased nutritive perfusion is sufficient to cover the blood supply and keep skin viable while subpapillary perfusion is low.

Neuropsychological Outcome 6 Months after Unilateral Carotid Stenting

Percutaneous transluminal angioplasty with stenting (PTAS) has become a treatment option for severe carotid stenosis. The goal of our study was to determine prospectively neurocognitive outcome 6 months after unilateral stent-protected carotid angioplasty. Twenty consecutive patients who underwent stent-protected angioplasty for symptomatic (n=9) or asymptomatic (n=11) high-grade carotid stenosis were investigated and compared to an age and disease matched control group. Patients were administered preprocedurally and 6 months postprocedurally a battery of neuropsychological tests. We used reliable change indices methodology in order to control for practice and statistical effects unrelated to intervention. We found no cognitive change in approximately 90% of patients and cognitive improvement in approximately 10% of patients for concentration and attention variables. We further found no cognitive change in 61% of patients, cognitive improvement in 11% of patients and cognitive deterioration in 28% of patients for psychomotor speed. No cognitive change in 94% of patients and cognitive deterioration in 6% of patients was found for sustained attention; no cognitive change in 80% of patients, cognitive improvement in 15% of patients and cognitive deterioration in 5% of patients was found for verbal fluency; no cognitive change in 100% of patients was found for interference (Stroop test): no cognitive change in 95% of patients, cognitive improvement in 5% of patients was found for interference (c.I. test), respectively. Our study showed that 6 months after PTAS cognitive functioning did not change in most patients significantly. For some patients, however, significant improvement or deterioration in single neurocognitive domains can be expected. The reasons for these changes are unclear but may depend on variable type; magnitude of microemboli production; right vs. left cerebral vasculature, respectively.

Covered Versus Bare Self-Expanding Stents for Endovascular Treatment of Carotid Artery Stenosis:A Stopped Randomized Trial

PURPOSE

To investigate whether filter-protected carotid artery stenting (CAS) using a covered self-expanding stent reduces the risk of cerebral embolization.

METHODS

Fourteen asymptomatic patients (13 men; median age 77 years, IQR 73-83) were enrolled in a randomized pilot trial comparing the rates of cerebral microembolism during and after filter-protected CAS using either a self-expanding covered (n=8) or a bare (n=6) carotid stent. Transcranial Doppler (TCD) monitoring was done during and for 90 minutes after the procedure. Diffusion-weighted magnetic resonance imaging (DW-MRI) was performed before and 24 hours after CAS. Patients were followed for 6 months for neurological events and occurrence of restenosis.

RESULTS

A significant reduction in ipsilateral microembolic signals by TCD was observed with the covered (median 1, IQR 0-4) versus the bare stent (median 6, IQR 3-8; p=0.043). Comparison of the preprocedural and 24-hour postprocedural DW-MRI images showed no new ipsilateral lesions but 1 new lesion in the contralateral hemisphere in the covered stent group, resulting in an overall 7% (95% CI 0%-20%) rate of new ischemic lesions. No neurological complications occurred up to 6 months. Restenosis (>70%) occurred in 3 (38%) of 8 patients with the covered versus none of the bare stents (p=0.21). The trial was stopped when the third restenosis of a covered stent was detected.

CONCLUSION

Self-expanding covered stents potentially reduce the risk of cerebral microembolism during and after carotid stenting. However, the problem of in-stent restenosis has to be resolved before these devices can be considered for further investigation.

Vascular dysfunction after coarctation repair is related to the age at surgery

BACKGROUND

Despite repair of aortic coarctation, hypertension is frequent in adults and premature coronary and cerebrovascular disease remain of concern. Persistent impairment of arterial dilation has been suspected to contribute to abnormal blood pressure regulation. We tested the hypothesis that arterial reactivity is more likely to be impaired in patients corrected at older age.

METHODS

We studied changes in brachial artery diameter in response to reactive hyperemia (FMD) and to nitroglycerin (NMD) in 36 patients and 25 controls. Depending on their age at surgery, patients were divided in group A (surgery <9 years) and group B (surgery > or =9 years).

RESULTS

Cholesterol levels and percentage of smokers were similar in patients and controls, but 16 patients had arterial hypertension compared to none of the controls. Endothelium-dependent vasodilation, FMD, and endothelium-independent vasodilation, NMD, were significantly impaired in patients vs. controls (8.2+/-6.2% vs. 13.0+/-5.1%, p<0.001 and 12.9+/-8.0% vs. 18.8+/-9.2%, p<0.01, respectively), both, in hypertensives (8.3+/-6.0%, p<0.01 and 11.8+/-6.0%, p<0.05) and in normotensives (8.1+/-6.5% p<0.01 and 13.8+/-9.3%, p<0.05). However, FMD and NMD in patients of group A did not significantly differ from that in controls (10.0+/-6.7% n.s. and 15.0+/-7.6% n.s.), whereas they were lowest in patients of group B (5.5+/-4.3%, p<0.0001 and 9.6+/-7.7% p<0.001).

CONCLUSIONS

Persistent impairment of FMD and NMD after repair of coarctation is more likely to be present in patients corrected at older age. It may be an important contributor to abnormal blood pressure regulation and late morbidity and mortality.

Quantification of Internal Carotid Artery Stenosis with Duplex US: Comparative Analysis of Different Flow Velocity Criteria

PURPOSE

To compare 13 previously published sets of duplex ultrasonographic (US) criteria with the US criteria used at the authors' institution in terms of agreement with carotid artery angiographic results.

MATERIALS AND METHODS

The authors studied 1,006 carotid arteries in 503 patients at duplex US and angiography. The degree of stenosis was determined by using duplex flow US velocities and applying 13 previously published sets of criteria and the criteria used at the authors' institution. Two independent observers evaluated the angiograms according to North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria. kappa statistics, sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and generalized linear mixed regression models were used to assess agreement between duplex US and angiographic findings.

RESULTS

Stenoses of 0%-29%, 30%-49%, 50%-69%, 70%-99%, and 100% could be differentiated with 73% overall agreement between duplex US and angiographic findings according to flow velocity criteria (kappa = 0.57; 95% confidence interval [CI]: 0.54, 0.60); however, with duplex US, the angiographic degree of stenosis tended to be overestimated. In the differentiation of stenoses of less than 70%, only 45% agreement (kappa = 0.26; 95% CI: 0.23, 0.29) was observed, whereas in the differentiation of high-grade (> or =70%) stenoses, 96% agreement was observed (kappa = 0.85; 95% CI: 0.83, 0.87). The PPV and NPV for the identification of 70%-99% angiographic stenosis were 69% and 98%, respectively, with use of the most sensitive duplex US criteria.

CONCLUSION

Duplex US is an excellent examination to screen for high-grade carotid artery stenosis; however, it tends to lead to an overestimation of the degree of stenosis. Exclusion of 70%-99% angiographic stenosis can be achieved with a sensitivity of up to 98%.

Hemostatic markers with bolus versus prolonged heparin after carotid artery stenting

BACKGROUND

The evolving technique of carotid stenting (CS) requires optimal antithrombotic strategies to reduce periinterventional thromboembolic risk. In animal models of balloon injury, tissue factor (TF) was shown to be the major procoagulant of the atherosclerotic plaque mediating prolonged procoagulant activity.

METHODS

We analyzed TF and TF-dependent hemostatic markers before and 2, 6 and 24 h after CS with two antithrombotic drug regimens. Group A (n=20) received prolonged unfractionated heparin (UFH) for 18-20 h starting at intervention next to aspirin and thienopyridine. In group B (n=16), single bolus UFH was administered next to combined antiplatelet therapy. Natural anticoagulants were determined at baseline.

RESULTS

Patients with symptomatic and asymptomatic cerebrovascular disease did not differ in plasma TF levels. Furthermore, no statistically significant difference for TF, TFPI/Xa-complex and prothrombin fragment F1.2 was observed between bolus and prolonged heparin treatment. No significant change was found in time course for these parameters. Two patients (5.5%; one in each treatment group) suffered periinterventional minor stroke associated with increased levels of F1.2 and TFPI/Xa-complex. Both were resistant to activated protein C (APC ratio<1.9) due to heterozygous factor V Leiden mutation.

CONCLUSIONS

No significant activation of the TF pathway was seen with both antithrombotic regimens suggesting that single bolus UFH combined with antiplatelet therapy is generally sufficient to control TF-dependent procoagulant activity after CS. However, patients with resistance to activated protein C may be at increased periinterventional stroke risk.

Carotid artery stenting: effect of learning curve and intermediate-term morphological outcome

PURPOSE

To assess the impact of learning on the rate of success and complications of carotid stenting in a single-center, one-operator series and prospectively follow a patient cohort with regard to restenosis.

METHODS

In 303 patients (mean age 70 +/- 8.8 years), 320 internal carotid arteries (ICA) were treated with carotid stenting for stenoses > or = 70%. Four groups of 80 consecutive interventions were compared with regard to primary technical success and periprocedural complications. Stent patency in follow-up was assessed using duplex scanning.

RESULTS

Stenting was successful in 298 (93%) arteries. The combined neurological complications (transient ischemic attacks and all strokes) and 30-day death rate was 8.2% (n = 25), but the all stroke and 30-day death rate was 3.0% (n = 9). A significant reduction in the frequency of neurological complications after the initial 80 interventions was observed (p = 0.03), but technical success was not appreciably improved with increasing experience thereafter. Over a median 12 months (interquartile range 6 to 24), cumulative patency rates were 91%, 90%, and 91% at 6, 12, and 36 months, respectively.

CONCLUSIONS

Elective carotid stenting can be performed with excellent technical success, an acceptable frequency of periprocedural complications, and good intermediate-term patency. However, our findings suggest that a larger number of interventions should be performed to overcome the negative effects of the initial learning phase.

Microcirculation is similar in ischemic and venous ulcers

Microcirculation of 15 ischemic and 15 venous ulcers, their scars, and intact surrounding skin were examined in order to demonstrate their similarities in the development and healing process. Subpapillary and nutritive perfusion of four areas were investigated by a laser Doppler perfusion imager (arbitrary units) and capillary microscopy (capillaries/mm2): one ulcer area without granulation tissue (no wound healing) and one with granulation tissue (ulcer healing); one skin area adjacent to the ulcer (1-8 mm) (scar developed from ulcer areas) and one distant (12-25 mm; intact skin). Areas without granulation tissue in ischemic and venous ulcers were similar, demonstrating a lack of capillaries (0.13 +/- 0.52; 0.93 +/- 2.09) and low laser Doppler flux (0.81 +/- 0.69; 1.47 +/- 1.17; P > 0.05 for each). In granulation tissue of both ulcers there was a tendency to a higher capillary density (0.67 +/- 1.40; 5.60 +/- 2.32; P < 0.0001 for venous ulcers) and a higher laser Doppler flux (1.15 +/- 0.67; 4.04 +/- 1.62; P < 0.0001 for venous ulcers) than in areas without granulation tissue. In scars of ischemic and venous ulcers capillary density (8.18 +/- 8.84; 13.60 +/- 5.45) and laser Doppler flux (1.72 +/- 1.00; 1.94 +/- 1.45) were similar (P > 0.05). In skin distant from ischemic ulcers very high capillary density (24.63 +/- 1.89) was associated with low laser Doppler flux (0.99 +/- 0.59); distant from venous ulcer capillary density was moderate (10.47 +/- 3.42) while laser Doppler flux was high (3.77 +/- 1.62; P < 0.0001 between both groups). The development and healing process of ischemic and venous ulcers is similar. Nutritive and subpapillary perfusion are involved in ulcer healing. In intact skin surrounding ischemic and venous ulcers, microcirculation is different due to the underlying pathophysiology.

Carotid stenting in a case of combined kinking and stenosis

Endarterectomy is currently the preferred treatment for severe carotid stenosis. The technique of eversion endarterectomy allows correction of severe vessel elongation and kinking. The latter is generally believed to be a relative contraindication for endovascular stent placement. We report successful percutaneous transluminal angioplasty and stenting of a left internal carotid artery with high-grade stenosis and severe kinking which was not amenable to endarterectomy because of the distal location of the stenosis. Advanced stent technology with flexible materials makes endovascular treatment of carotid stenosis feasible even in cases of kinking.

[The indications and embolism monitoring in lumen-opening therapies of the a. carotis]

Carotid endarterectomy (CEA) is proven to be beneficial in symptomatic patients with high-grade carotid stenosis (70% to 99%; residual lumen as a percentage of the normal distal internal carotid artery) on condition that the peri-operative risk for mortality and morbidity is less than 6%. A minority of the "leading experts" in North America (48%) and Western Europe (28%) recommends carotid endarterectomy in asymptomatic patients in general. Most experts suggest to perform surgery only in asymptomatic patients who are at risk for carotid occlusion in the near future or embolism. At its present state, angioplasty and stenting is an experimental although promising technique which will have to be compared to carotid endarterectomy. Criteria for duplex grading of internal carotid stenosis have been established and systematically validated to results of angiography. Pre-surgical use of angiography will more and more be restricted to selected patients in whom the results of duplex sonography remain inconclusive. The detection of microemboli with transcranial doppler sonography seems to be of particular importance before and during carotid angioplasty and stenting.

Impact of different therapeutic alternatives in treatment of severe limb ischemia: experiences on 190 consecutive patients at a department of medical angiology

BACKGROUND

Different therapies in consecutive patients (1987-1992) with chronic critical limb ischemia at a department of medical angiology, their short- and long-term outcome were investigated.

PATIENTS AND METHODS

190 patients (112 males, 78 females; age: 67 +/- 12 years); 78 in grade II, 112 in grade III according to Rutherford's classification. Therapeutic regimen: 1. vascular recanalisation by percutaneous transluminal angioplasty [PTA], local or systemic lysis; 2. surgical vascular reconstruction in case of impossibility or failure of catheter procedures; 3. prostanoids and/or antibiotics; 4. local wound treatment including amputations.

RESULTS

Vascular recanalisation was attempted in 156/190 (82.1%): PTA in 116/190, surgical vascular reconstruction in 50/190, local in 24/190 and systemic lysis in 8/190 patients. Prostanoids were applied in 89/190 and antibiotics in 73/190 patients. At the time of dismissal 164/190 (86.3%) patients were clinically improved; 11/190 (5.8%) unchanged, 13/190 (6.8%) had undergone major amputations and 2/190 (1.1%) had died. After 2.6 +/- 2.2 years 77 of the 141 patients, who were still alive, were reexamined. Among these 77 patients 84.4% were in grade 0 or 1, 15.6% in chronic critical limb ischemia. Furthermore 13.0% had been amputated since dismissal. Forty-nine of 190 (25.8%) patients had died 3.2 +/- 1.9 years after dismissal from hospital.

CONCLUSION

Catheter techniques, mostly PTA, is possible in the majority of patients with chronic critical limb ischemia. Cooperation with vascular surgeons in case of technical impossibility or failure of catheter recanalisation is mandatory. Such a regimen yields satisfactory short- and long-term results and a low rate of complications.

Microcirculation in venous ulcers and the surrounding skin: findings with capillary microscopy and a laser Doppler imager

BACKGROUND

To obtain more information about microcirculatory disturbances in venous ulcers, we studied their laser Doppler flux images and capillary densities.

MATERIALS AND METHODS

On photographs of venous ulcers and the adjacent skin of 17 patients, four regions of interest were marked: one non-granulation tissue area (NGTA) within the venous ulcer, one granulation tissue area (GTA) within the ulcer, one adjacent skin area (ASA) and one distant skin area (DSA). Within these four regions the average laser Doppler area fluxes and capillary densities were determined for each patient using a laser Doppler imager and capillary microscopy respectively.

RESULTS

The laser Doppler area flux (mean +/- SD in AU) was significantly lower in NGTA (1.39 +/- 1.12) than in GTA (4.06 +/- 1. 52) or DSA (3.86 +/- 1.54) (P < 0.00001). In addition, the ASA flux (1.95 +/- 1.39) was significantly lower than the GTA or DSA flux (P < 0.0001). Capillary density (capillaries per mm2) in NGTA (0.82 +/- 1.98) was significantly lower than that in GTA (6.00 +/- 2.55), ASA (13.88 +/- 5.16) or DSA (10.29 +/- 3.41) (P < 0.0001). In addition, the capillary density of ASA was significantly higher than that of GTA or DSA (P < 0.05).

CONCLUSION

The four areas showed the following characteristics: NGTA, low laser Doppler area flux and lowest capillary density (possible sign of ulcer area without healing tendency); GTA, high laser Doppler area flux and second lowest capillary density (possible sign of wound healing); ASA, low laser Doppler area flux and highest capillary density (possible sign of healing process nearly completed; scar); DSA, high laser Doppler area flux and second highest number of capillaries (sign of microcirculation of chronic venous disorder).

Laser Doppler imaging and capillary microscopy in ischemic ulcers

The local distribution of laser Doppler flux (mainly thermoregulatory perfusion) and capillary density (nutritive circulation) within 25 ischemic leg ulcers and their adjacent skin were investigated. For this purpose the technique of laser Doppler imaging and capillary microscopy were applied. In each ulcer a non granulation tissue area (NGTA), a granulation tissue area (GTA) and in adjacent skin a skin area (SA) were defined. In these areas the average laser Doppler area flux (arbitrary units, AU) and the number of capillaries/mm2 were determined for each patient. The mean+/-S.D. of laser Doppler area fluxes were: NGTA 1.30+/-1.93, GTA 2.13+/-1.53 and SA 1.21+/-0.77 AU, respectively. The differences between GTA and NGTA or SA was statistically significant (p < 0.001, each) The mean+/-S.D. of capillary densities were as follows: NGTA: 0.56+/-2.06, GTA 6.76+/-8.39 and SA 16.80+/-7.38 capillaries/mm2, respectively. The following differences were statistically significant: NGTA versus GTA (p < 0.01) and SA versus NGTA or GTA (p < 0.001, each). In conclusion following characteristics of the three areas can be described: In NGTA low laser Doppler area flux is combined with very low capillary density (ulcer area without healing). In GTA the highest laser Doppler area flux of all three areas and an intermediate capillary density (wound healing) is found. In SA an intermediate laser Doppler area flux is associated with the highest capillary density of all three areas with the healing process nearly completed and no granulation tissue.

Granulocyte colony-stimulating factor (rh G-CSF) as an adjunct to interferon alpha therapy of neutropenic patients with hairy cell leukemia

Six patients with hairy cell leukemia (HCL) and neutropenia (median neutrophil count 563/microliters, range 30-1200) were treated with recombinant human granulocyte colony-stimulating factor (G-CSF) at a dose of 5 micrograms/kg by daily subcutaneous injection as an adjunct to interferon-alpha (IFN-a) therapy, in order to ameliorate neutropenia. Five of six patients responded to G-CSF with normalization of neutrophil counts (> 1800/microliters) within 2-11 days and a median neutrophil count of 5211/microliters (range 4312-10160) at the end of G-CSF therapy. In three of these patients, infections resolved when neutropoiesis recovered. In one patient with very severe neutropenia (30/microliters), in whom myeloid progenitors were not detectable, G-CSF therapy failed to restore granulopoiesis. Cessation or interruption of G-CSF after 2-5 weeks of therapy resulted in a rapid decline of neutrophil counts to lower or subnormal levels (median value 1478/microliters, range 770-2739) within 1 week, suggesting that the improvement of granulopoiesis was dependent on G-CSF and not due to IFN-a therapy. G-CSF may be a useful adjunct to IFN-a therapy in patients with HCL in order to manage or prevent neutropenic complications in the early phase of treatment.

Treatment of drug-induced agranulocytosis with recombinant granulocyte colony-stimulating factor (rh G-CSF)

Five patients with drug-induced agranulocytosis received 300 micrograms recombinant human granulocyte colony-stimulating factor (rh G-CSF) subcutaneously twice daily for 2-5 days. G-CSF therapy resulted in a steep increase of the neutrophil count, which was faster than that in patients with spontaneous recovery reported in the literature. In all four patients with infectious complications fever rapidly declined with the increase of granulocytes. G-CSF may be useful in the management of drug-induced agranulocytosis.