Microcirculation after standardized application of Essaven gel on normal skin--a placebo-controlled, randomized study

Essaven gel (EG) is a naturally derived compound indicated for the treatment of impaired venous circulation and, in microcirculatory disorders, hematomas, swelling, sprains, and all minor sport injuries. The aim of this randomized, placebo-controlled, double-blind study was to evaluate the standardized application of EG on normal skin and its effects on the microcirculation. Standardization of gel application (particularly EG) has been recently described (in healthy subjects and in clinical studies) in defined steps. The results of this study indicate that topical treatment with EG is effective in improving or positively altering the microcirculation in normal skin both at the deeper capillary levels (thermoregulatory, whole-thickness capillary bed [as shown by laser Doppler flowmetry] as well as at the nutritional capillary layer (as shown by PO2). The application of EG can be standardized to obtain consistent results with topical treatment.

Essaven gel--review of experimental and clinical data

Essaven gel (EG) has been developed for local treatment of venous and microcirculatory alterations (varicose veins, chronic venous insufficiency, associated signs and symptoms). Sport injuries (bruises, swelling secondary to sprains and contusions) respond favorably to EG, which is also indicated for varices in pregnancy. Active ingredients of EG are aescinate, sodium heparin, and essential phospholipids (EPL). The dose in 100 g of EG are: 1 g of aescinate, 10,000 IU of sodium heparin, and 1 g EPL. EG is applied several times daily in a thin film. Clinical reports on the activity of EG include several vascular applications in which the product is effective without contraindications or side effects. On the basis of this review, EG offers important therapeutic benefits to several types of patients and the product should be available for its usefulness and safety.

Improved hemodynamic effectiveness and associated clinical correlations of a new intermittent pneumatic compression system in patients with chronic venous insufficiency

PURPOSE

A new intermittent pneumatic compression device (SCD Response System) has recently been shown in healthy volunteers to have the ability to detect the postcompression refilling of the calf veins and to respond by initiating the subsequent cycle when these veins are full. This has proven to be more effective in expelling blood proximally than the conventional intermittent pneumatic compression device (SCD Sequel System). The aim of this study was to test the influence of venous disease on the postcompression refill time detected by means of the SCD Response and the effectiveness of the new system in expelling blood in patients who have venous reflux caused by post-thrombotic syndrome or varicose veins.

METHODS

This open, controlled trial was conducted in an academic vascular unit with 10 patients who had post-thrombotic syndrome and 10 patients who had varicose veins. The new SCD Response System was tested against the existing SCD Sequel System in both legs in the supine, semirecumbent, and sitting positions. The refilling time sensed by means of the device was correlated with the venous filling index by using air plethysmography. The total volume of blood expelled per hour during compression was compared with that expelled by the SCD Sequel System in the same volunteers and in the same positions.

RESULTS

An inverse association was found between the mean postcompression refilling time in the sitting position and the venous filling index of the apparently healthy or less severely affected leg (r = -0.52, P =.019), the refill time being significantly shorter in patients with advanced venous disease. The SCD Response System increased the volume expelled per hour in the post-thrombotic leg, when compared with the SCD Sequel System, by 109.9% (P =.005) in the supine position, by 85.1% (P =.009) in the semirecumbent position, and by 40.2% (P =.005) in the sitting position. The corresponding results in the more severely affected leg in patients with varicose veins were 71.9% (P =.005) in the supine position, 77.9% (P =.005) in the semirecumbent position, and 55.7% (P =.013) in the sitting position. Similar improved results were also found in the contralateral leg in both groups.

CONCLUSIONS

The deflation settings of the new SCD Response System are able to be adjusted selectively, correlating with the physiological severity of chronic venous insufficiency. By achieving more frequent compression cycles, the new system is more effective than the current one in expelling blood proximally, confirming our earlier findings in healthy volunteers. Further studies testing a possible improved efficacy in preventing deep venous thrombosis in this high-risk group are justified.

Peripheral sympathetic autoregulation in arterial calf inflow enhancement with intermittent pneumatic compression

BACKGROUND

Peroperative mortality, graft failure and balloon angioplasty limitations mitigate against active intervention for claudication. With the exception of exercise programmes, conservative treatments yield limited results. Intermittent pneumatic compression of the foot (IPC(foot)) used daily for over 3 months enhances significantly the walking ability and pressure indices of stable claudicants; this is attributable to the significant calf inflow enhancement with IPC(foot); however, the physiologic mechanisms involved are only partially understood. Aims by comparing the effects of IPC(foot)and postural alteration on calf inflow haemodynamics, this study examines the role of peripheral sympathetic autoregulation, which controls homeostasis in lower limb vessels when posture changes, in the enhancement of calf inflow with IPC(foot)in healthy subjects and claudicants.

MATERIAL AND METHODS

forty-one limbs of healthy subjects (n =34; Group I) and 48 limbs of stable claudicants (Fontaine II) (n =42; Group II) were studied. The volume flow (Q), pulsatility index (PI), mean (mV), peak systolic (PSV) and end diastolic (EDV) velocities were measured in the popliteal artery using duplex ultrasound in: the horizontal position, and on sitting with or without IPC(foot).

RESULTS

in Group II: median Q, mV, PSV and EDV increased by 61%, 53%, 29% and 51% respectively, and PI decreased by 20% as posture changed from sitting to horizontal; with IPC(foot)median Q, mV, PSV and EDV increased by 70%, 58%, 22% and 75% respectively, and PI decreased by 26% (all p < 0.001). In Group I: median Q, mV, PSV and EDV increased by 125%, 115%, 51% and 38% respectively and PI decreased by 30% as posture changed from sitting to horizontal; with IPC(foot)median Q, mV, PSV and EDV increased by 119%, 153%, 23% and 46%, respectively, and PI decreased by 50% (all p < 0.001). The effects of IPC(foot)and postural alteration (from sitting to horizontal) did not differ haemodynamically (p > 0.1) in both groups. Q on lying was similar in Groups I and II. On sitting Q was higher in Group II [p =0.027 (95% CI 1.7, 27 ml/min)].

CONCLUSIONS

the striking similarity in the haemodynamic effects of IPC(foot)and postural alteration in the popliteal artery strongly suggests that the leg inflow enhancement with IPC(foot)is mediated by a transient suspension of peripheral sympathetic autoregulation. In addition to their role as clinical markers of PVD severity, the autoregulatory reflexes of peripheral circulation appear to have functions with significant clinical implications in the management of patients with leg inflow impairment.

Increase in echogenicity of echolucent carotid plaques after treatment with total triterpenic fraction of Centella asiatica: a prospective, placebo-controlled, randomized trial

The aim of this study was to evaluate whether total triterpenic fraction of Centella asiatica (TTFCA), was effective in modulating collagen production over 12 months, by producing an increase in echogenicity in echolucent carotid plaques. Part I was a pilot study aimed at evaluating the effects of TTFCA on different types of plaques. Part II was a prospective, randomized, placebo-controlled trial aimed at evaluating the effects of TTFCA on hypoechoic-echolucent plaques. The sonographic examination of carotid plaques was made with high-resolution ultrasound. Capturing, digital image processing, and normalization were standardized, interobserver, intrascanner, gain-level variability were standardized using as reference blood (black) for the most echolucent parts of the plaque and the adventitia (white) as the most echogenic part. Normalization of echo texture was obtained and plaque characterization differentiated echo-texture of plaque associated with events and those that did not cause embolization, thrombosis, or cardiovascular events. After identifying plaques at higher risk, patients were treated with TTFCA (oral tablets, 60 mg, thrice daily for 12 months) to evaluate whether this compound, by modulating collagen synthesis, could increase the echogenicity and therefore the stability of echolucent plaques. Part II was aimed at evaluating the effects of TTFCA on hypoechoic-echolucent plaques. Asymptomatic patients with echolucent plaques (GSM<18) were treated with TTFCA (60 mg, oral tablets three times daily for 12 months) or with comparable placebo after informed consent. All patients were also treated with antiplatelet agents. In part 1, at inclusion the GSC in the hypoechoic group was 15 (range, 12-18) while in the hyperechoic group it was 26 (range, 24-31); at 6 months it was increased in the hypoechoic group and at 12 months the increase was significant (19.5; p<0.05). There was a minor increase in GSM in the hyperechoic group (30; ns). In part II in the treatment group there was a significant difference in GSM (increase) at 12 months (p<0.05), improvement in texture (p<0.05) and a nonsignificant decrease in stenosis. No changes were observed in the placebo group. Events were observed in 6.5% of patients in the TTFCA group and in 11% in the control group (p<0.05). In conclusion these observations suggest a positive action of TTFCA on the stabilization of hypoechoic, low-density carotid plaques.

Modification of the echogenicity of femoral plaques after treatment with total triterpenic fraction of Centella asiatica: a prospective, randomized, placebo-controlled trial

The aim of this study was to evaluate whether TTFCA (total triterpenic fraction of Centella asiatica), was effective, by modulating collagen production, in a period of 12 months, increasing the echogenicity of echolucent plaques at the femoral bifurcation. Hypoechoic atherosclerotic plaques have been found to be associated with an increased evidence of cerebrovascular events. In this type of plaques stromal composition is limited as the collagen component is generally very low; the plaque composition is mainly due to lipid accumulation or thrombosis. The aim of this study was the evaluation of echogenicity of hyperechoic plaques and how it could be modified by a drug acting on the modulation of collagen synthesis. Antiplatelet agents were used in all patients; cholesterol-lowering agents were used in 34% of patients in the treatment group and in 36% in the placebo group. TTFCA was used at the dose of 60 mg thrice daily (oral tablets). Of the 60 included subjects 26 completed the study in the treatment group and 24 in the placebo group. At inclusion the average GSM in the treatment group was 14 (SD 3) and 14.3 (SD 3) in controls. At 12 months GSM was increased up to 22.8 (SD 4) in the treatment group and it was 15 (SD 3) in controls. Considering texture no significant changes were observed in controls while a qualitative increase in homogenicity was observed in the TTFCA group. Plaque size measured at the beginning and at the end of the study showed a median increase in size, in controls (23%; range 0%-44%); it was unchanged in the TTFCA group (variation 7%; 4%-26%). In conclusion in the treatment group plaques increased in echogenicity and in homogenicity; size and stenosis remained unchanged. Modulating the scarring process within echolucent plaques (low echogenicity, high echolucency, with a very low collagen/stromal component), possibly by collagen modulation, makes plaques more stable. This has been achieved and documented in the present study by an increase in the gray-scale median (plaques become more echogenic, more 'white'). The variation in GSM is generally associated with a lower risk of wall thrombosis, rupture and embolization. These observations indicate a positive action of TTFCA on the stabilization of hypoechoic, low-density femoral plaques.

Incidence, natural history and risk factors of deep vein thrombosis in elective knee arthroscopy

AIMS

to determine the incidence, anatomical distribution and extent of deep vein thrombosis (DVT) in limbs undergoing elective unilateral knee arthroscopy without active prophylaxis, to evaluate its effect on venous function following early diagnosis, and to quantify the impact of risk factors on its incidence.

METHODS

102 consecutive patients undergoing unilateral knee arthroscopy without prophylaxis were studied. A history was obtained with emphasis on the risk factors for thromboembolism, and physical examination and colour duplex were performed prior to and within a week after surgery. Patients who developed calf DVT were given aspirin (150 mg) and compression stockings; those with proximal DVT were admitted for anticoagulation (heparin followed by warfarin). Follow-up (mean 118 [range 84-168] days) entailed weekly physical and duplex examinations during the first month and monthly thereafter.

RESULTS

8 patients developed calf DVT in the operated leg (incidence 7.84% [95% CI: 2.7%-13.2%]); thrombosis was asymptomatic in 4 of those (50%), caused calf tenderness in 4 (50%) and a positive Homan's sign in one (12.5%). DVT occurred in the following veins: peroneal 4 subjects (50%), soleal 4 (50%), gastrocnemial 2 (25%) and tibial 2 (25%). Propagation of a calf DVT to the popliteal vein was identified in 1 patient (12.5%). After a median period of 118 days, total clot lysis was found in 50% of DVTs. with partial thrombus resorption in the rest; reflux in the thrombosed veins was present in 75% of limbs with DVT. 43% of patients had 1 risk factor for DVT and 20% had > or = 2. The incidence of DVT was higher amongst those with two or more risk factors for thromboembolism (p <.05) or those with previous thrombosis alone (p <.005). Symptoms or signs of pulmonary embolism were not documented.

CONCLUSIONS

Elective unilateral knee arthroscopy performed without prophylaxis is complicated by ipsilateral calf DVT in 7.8% (95% CI: 2.7%-13.2%) of cases. The risk is higher in the presence of previous thrombosis (relative risk: 8.2) and two or more risk factors for DVT (relative risk: 2.94). Thrombosis may propagate to the proximal veins, despite early diagnosis. 50% of calf clots totally lyse in 4 months, yet reflux develops in at least 75% of limbs with DVT. Further studies to determine optimal prophylaxis are warranted.

Significance of sonographic tissue and surface characteristics of carotid plaques

BACKGROUND AND PURPOSE

Our hypothesis was that symptomatic and asymptomatic carotid plaques are different. The aim of this study was to identify the sonographic tissue and surface characteristics of plaques and their degree of stenosis that corresponded to these two clinical presentations.

METHODS

We studied 81 symptomatic and 111 asymptomatic plaques (150 patients) having 50% to 99% stenosis on duplex scanning. These plaques were imaged on duplex and captured in a computer. We evaluated the gray-scale median (GSM) to distinguish hypoechoic (low GSM) from hyperechoic (high GSM) plaques, and the bending energy (BE), to distinguish plaques with irregular (high BE) versus smooth (low BE) surfaces.

RESULTS

The symptomatic group corresponded to hypoechoic (median GSM, 4) and severely stenosed (median stenosis, 85%) plaques, whereas the asymptomatic group corresponded to hyperechoic (median GSM, 35) and moderately stenosed (median stenosis, 70%) plaques (P <.05 for both variables). The BE failed to separate the two groups; the mean BEs were 1.63 and 1.68 for the symptomatic and asymptomatic groups, respectively (P =.38).

CONCLUSION

Our results suggest that echogenic characteristics and the degree of stenosis are the strongest predictors of carotid plaque behavior. The sonographic surface characteristics failed to qualify as an index of plaque instability.

Correlation between carotid artery distensibility and serum vascular endothelial growth factor concentrations in type 1 diabetic subjects and nondiabetic subjects

The relationships between serum vascular endothelial growth factor (VEGF) concentrations and vessel wall ultrasonic characteristics in type 1 diabetic and nondiabetic subjects were assessed. Serum VEGF concentration was measured, and ultrasound imaging and blood pressure recordings were performed in 41 type 1 diabetic subjects (hemoglobin A(1c) [HbA(1c)], 7.63 [1.17%]; duration of diabetes, 12 (0 to 23) years), and 50 nondiabetic subjects. Change in carotid artery luminal diameter during the cardiac cycle was measured using M-mode ultrasound, from which percentage increase in carotid artery luminal diameter was calculated; the carotid artery distensibility index was calculated as the ratio of percentage increase in carotid artery luminal diameter and pulse pressure. Serum VEGF concentration was higher in the diabetic subjects (217 [135 to 336] v 137 [80 to 237] pg/mL; P =.009). The percentage increase in carotid luminal diameter during the cardiac cycle was not significantly different between the 2 groups (12.9 [10.2 to 15.7] v 13.0 [10.6 to 15.0%]; P =.270) despite significantly greater pulse pressure in the type 1 diabetic group (55 [45 to 71] v 46 [41 to 51] mm Hg; P =.0003). The distensibility index was therefore lower in the diabetic subjects (0.24 [0.10] v 0.28 [0.08%]/mm Hg; P =.031). There was a significant negative correlation between serum VEGF concentrations and mean percentage increase in carotid luminal diameter during the cardiac cycle in the diabetic group (r = -.36, P =.021) and in the nondiabetic group (r = -.28, P =.047). This negative correlation could be strengthened by relating mean percentage increase in luminal diameter to pulse pressure to give the distensibility index. Therefore, serum VEGF concentrations correlated strongly and inversely with the distensibility index in the diabetic group (r = -.49, P =.001), in the nondiabetic group (r = -.29, P =.041), and in both groups analyzed together (r = -.42, P <.0001). Vessel wall distensibility may be an important determinant of serum VEGF concentrations in both diabetic and nondiabetic populations and may underlie the previously observed association between blood pressure and serum VEGF concentrations. The pathophysiologic relevance of these findings remains to be elucidated.

Determinants of carotid plaque instability: echoicity versus heterogeneity

OBJECTIVE

to identify the echoicity and heterogeneity of carotid plaques associated with ipsilateral symptomatic and asymptomatic neurovascular presentations.

DESIGN

cross-sectional study.

MATERIALS

a total of 113 patients, with 127 symptomatic and asymptomatic plaques, were studied.

METHODS

the duplex images of the plaques were analysed echoically in a computer by means of Grey Scale Median (GSM) [hypoechoic (low GSM), hyperechoic (high GSM)]. The presence or absence of at least two plaque regions within the plaque area being echoically uniform (no variation of echoicity), occupying each at least 10% of the plaque area and having GSM difference greater than the plaque GSM was evaluated to distinguish the heterogeneous (presence of this pattern) from the homogeneous (absence of this pattern) plaques.

RESULTS

the symptomatic status was associated with plaques of low median GSM (10.5) and 88% prevalence of the homogeneous pattern as contrasted with the asymptomatic status that was associated with high median GSM (28) and 65% prevalence of the homogeneous pattern [(p=0.001 (GSM), p=0.003 (heterogeneity)].

CONCLUSIONS

symptomatic plaques were associated with hypoechoic and predominant homogeneous echo-pattern whereas the asymptomatic ones were associated with hyperechoic and less predominant homogeneous pattern.

Venous thromboembolism from air travel: the LONFLIT study

The LONFLIT study was planned to evaluate the incidence of deep venous thrombosis (DVT) occurring as a consequence of long flights. In the Lonflit study 355 subjects at low-risk for DVT and 389 at high-risk were studied. Low-risk subjects had no cardiovascular disease and used no drugs. All flights were in economy class. The average flight duration was 12.4 hours (range, 10-15 hr). The mean age of the studied subjects was 46 years (range 20-80 yr, SD 11; 56% males). DVT diagnosis was made by ultrasound scans after the flights (within 24 hours). In low-risk subjects no events were recorded while in high-risk subjects 11 had DVT (2.8%) with 13 thromboses in 11 subjects and 6 superficial thromboses (total of 19 thrombotic events in 389 patients [4.9%]). In the Lonflit2 study the authors studied 833 subjects (randomized into 422 control subjects and 411 using below-knee stockings). Mean age was 44.8 years (range, 20-80 yr, SD 12; 57% males). The average flight duration was 12.4 hours. Scans were made before and after the flights. In the control group there were 4.5% of subjects with DVT while only 0.24% of subjects had DVT in the stockings group. The difference was significant. The incidence of DVT observed when subjects were wearing stockings was 18.75 times lower than in controls. Long-haul flights are associated to DVT in some 4-5% of high-risk subjects. Below-knee stockings are beneficial in reducing the incidence of DVT.

Brain CT infarction in patients with carotid atheroma. Does it predict a future event?

BACKGROUND

The aim of the present study was to investigate the predictive value for subsequent stroke of different patterns of brain CT infarction in patients with carotid atheroma.

METHODS

Prospective study on 138 patients, with 138 carotid plaques, having, on presentation, a greater than 50 percent stenosis on duplex scanning and associated with an ipsilateral (to the plaque) amaurosis fugax (AF), hemispheric transient ischaemic attack (HTIA) or which were asymptomatic. This carotid artery defined the side of interest. All patients had a brain CT scan on presentation and subsequently were followed for a period of 1-5 years (mean 3.14). The baseline CT neurovascular findings on the side of interest were classified as pattern A (discrete subcortical and cortical infarctions), pattern B (haemodynamic infarctions, widespread white matter lesions, basal ganglia infarctions and lacunae) and normal CT.

RESULTS

On follow-up, 5/27 (18.5 percent) of patients with pattern A, 4/38 (10.5 percent) with pattern B and 3/73 (4.1 percent) with normal CT appearance developed stroke in the hemisphere of interest (Cox regression: p=0.02).

CONCLUSIONS

Pattern A confers an unfavourable prognosis in patients with carotid atheroma who are either asymptomatic or presented with amaurosis fugax or hemispheric transient ischaemic attacks.

Oxygen-free radical decrease in hypertensive patients treated with lercanidipine

BACKGROUND

The relationship between oxidative stress, lipoproteins, cardiovascular risk factors and vascular disease progression has recently attracted fresh attention due to the possibility of measuring free radicals (FRs). The aim of this study was to evaluate blood plasma variations in oxygen FRs in hypertensive patients treated with lercanidipine, a drug acting on blood pressure and microcirculation.

METHODS

Twenty-two patients with moderate hypertension (M:F=12:10; age=52) and no vascular disease (evaluated by high-resolution ultrasound) were treated for 24 weeks with Lercanidipine (10 mg/day or 20 mg/day if BP values did not decrease at least 15 percent after four weeks of treatment). BP was measured at inclusion and after 4, 8, 12 and 24 weeks of treatment. FRs measurements (using the D-Roms test) were made at inclusion, at the 8th, 12th and 24th week.

RESULTS

All patients completed the treatment which was well tolerated and without side effects. Systolic and diastolic BP decreased after 8, 12 (p<0.05) and 24 weeks (at 24 weeks systolic pressure was decreased by 21.1 percent, and diastolic by 11.1 percent; p<0.02). FRs levels progressively decreased from 541 Carr Units (SD 54) at inclusion to 411 (SD 56) at eight weeks (p<0.05), to 401 (SD 35) (p<0.05) at 12 weeks and finally to 398 (SD 33), (p<0.02) at 24 weeks of treatment (72.2 percent of the initial value).

CONCLUSIONS

The possibility of measuring FRs in vivo with a simple, inexpensive test allows the identification of subjects with a high level of oxidative stress, and the monitoring of the effects of treatments. Lercanidipine, acting on blood pressure, on the microcirculation and decreasing oxidative stress and Frs plasma levels may effectively decrease the rate of progression of cardiovascular diseases offering the advantage of an increased level of protection in patients with high levels of oxidative stress.

Carotid and femoral ultrasound morphology screening and cardiovascular events in low risk subjects: a 10-year follow-up study (the CAFES-CAVE study(1))

BACKGROUND

Subclinical arteriosclerotic lesions at the carotid and femoral bifurcations may be related to the occurrence of future cardiovascular events and of occult arteriosclerotic coronary disease. B-mode ultrasound of carotid and femoral arteriosclerotic bifurcation lesions may provide a simple screening method to select asymptomatic subjects at risk of future events.

METHODS AND RESULTS

13221 low-risk, healthy, asymptomatic individuals were included in a 10-year, prospective, follow-up based on carotid and femoral bifurcation morphology defined by B-mode ultrasound. Four classes were considered at inclusion (I: normal wall, II: wall thickening, III: non-stenosing plaques, IV: stenosing plaques). When 10000 subjects (75.6% of included subjects; 6055 males, 3945 females) completed the 10-year follow-up the study was concluded. At 10 years there were 10 events (out of 7989 subjects) in class I and 81 events in II (930 subjects; incidence=8.6%); 239 events were observed in class III (611 subjects; 39.28%) and 381 events (470 subjects; 81.06%) in IV; 61 deaths occurred in classes III+IV (1081 subjects) producing a death rate within these two classes of 5.5% (51 out of 61=81.5% in class IV). The increased event rates in classes III and IV were significant (log rank; P<0.02) in comparison with I and II.

CONCLUSIONS

Carotid and femoral morphology identified 2011 subjects (20.1% of the population) in classes II,III,IV including 98.6% of cardiovascular events and deaths in the following 10 years. A higher (P<0.05) rate of progression in classes III and IV in comparison with I and II was also observed. The ultrasound carotid and femoral classification was useful in selecting subjects at very low risk of cardiovascular events (class I), those at limited risk (class II) and a group at moderate risk (class III). A subpopulation at high risk of cardiovascular events (IV) was identified.

Air plethysmography: the answer in detecting past deep venous thrombosis

PURPOSE

In this study we assessed the accuracy of air plethysmography (APG) as a means of detecting earlier deep venous thrombosis (DVT), in comparison with venography, to develop a preoperative test for patients with varicose veins.

METHODS

In this retrospective analysis of prospectively acquired data, 202 patients referred with the clinical suspicion of chronic venous obstruction (224 lower limbs) and 41 patients (41 lower limbs) who had symptoms and signs suggestive of DVT, but had deep veins that appeared normal on venography, were studied with both venography and APG.

RESULTS

The results of venography were negative for past DVT in 169 legs and confirmed past DVT in 96 limbs. The DVTs were confined to the calf in 19 limbs and were found at popliteal level, more proximal, or both in 77 limbs. A total of 95% of the limbs that had earlier proximal DVT (73 of 77) were identified by means of an APG outflow fraction with occlusion of the superficial veins in the first second (OFs) of less than 28%. This is analogous to the Q wave of the electrocardiogram, which is a means of denoting the presence of myocardial infarction. The specificity rate of the method in the detection of past proximal DVT was 96%, the positive predictive value was 92%, and the negative predictive value was 98%.

CONCLUSION

APG is a practical, inexpensive, easy-to-perform, accurate, noninvasive method for the diagnosis of hemodynamically significant (ie, proximal or extensive calf DVT) chronic venous obstruction that could replace venography.

Sympathetic autoregulation in peripheral vascular disease

BACKGROUND

Lower limb venous pressure increases on dependency, stimulating a local sympathetic axon reflex which triggers precapillary and arteriolar vasoconstriction. The resulting decrease in arterial calf inflow, known as the venoarteriolar response (VAR), is impaired in critical leg ischaemia. The aim of the study was to evaluate the VAR in symptomatic non-critical leg ischaemia and after restoration of leg perfusion following successful revascularization.

METHODS

The study included 30 normal subjects, 30 patients with stable intermittent claudication and 30 patients with severe ischaemia who had undergone successful infrainguinal revascularization. In all patients the foot skin blood flow (flux) in the horizontal (HBF) and sitting (SBF) positions was measured using laser Doppler fluxmetry. The VAR was calculated as (HBF - SBF)/HBF x 100 per cent. The pressure that elicited the reflex (pVAR) was evaluated in the horizontal position.

RESULTS

The median VAR was significantly lower in patients with stable claudication than in normal subjects or patients following successful revascularization (29.1 versus 59.5 and 63.9 per cent respectively; P < 0.0001). Similar results were obtained for the pVAR (22 versus 45 and 40 mmHg respectively; P < 0.001). There was no difference, however, in either the VAR or pVAR between normal individuals and patients following a successful bypass.

CONCLUSION

Patients with claudication had a significant impairment of orthostatic sympathetic autoregulation. After successful revascularization, and in spite of the extensive disease in the receiving circulation, this autoregulation returned to normal. Presented previously to the Vascular Surgical Society in London, November 1997 and published in abstract form as Br J Surg 1998; 85: 557

In situ hemodynamics of perforating veins in chronic venous insufficiency

PURPOSE

The prevalence of incompetent perforators increases linearly with the clinical severity of chronic venous insufficiency (CVI) and the presence of deep vein incompetence. Putative transmission of deep vein pressure to skin may cause dermal hypoxia and ulceration. Despite extensive prospective interest in the contribution of perforators toward CVI, their hemodynamic role remains controversial. The aim of this prospective study was to determine the in situ hemodynamic performance of incompetent perforating veins across the clinical spectrum of CVI, by means of duplex ultrasonography.

METHODS

A total of 265 perforating veins of 90 legs that had clinical signs and symptoms consistent with CVI in 67 patients referred consecutively to the blood flow laboratory were studied. The clinical distribution of the examined limbs was CEAP(0), 10 limbs; CEAP(1-2), 39 limbs; CEAP(3-4), 21 limbs; and CEAP(5-6), 20 limbs. With the use of gated-Doppler ultrasonography on real-time B-mode imaging, the flow velocity waveforms were obtained from the lumen of perforators on release of manual distal leg compression in the sitting position and analyzed for peak and mean velocities, time to peak velocity, volume flow, venous volume displaced outward, and flow pulsatility. The diameter and duration of outward flow (abnormal reflux > 0.5 seconds) were also measured.

RESULTS

Incompetent perforators had bigger diameters, higher peak and mean velocities and volume flow, longer time to peak velocity, and bigger venous volume displaced outward (VV(outward)) than competent perforators (all, P <.0001). The diameter of incompetent perforators did not change significantly with CEAP class (all, P >.1). Incompetent thigh and lower-third calf perforators had a significantly bigger diameter than perforators in the upper and middle calf combined (both, P <.05), in incompetent perforators: reflux duration was unaffected by CEAP class or site (P >.3); peak velocity was higher in those in CEAP(3-4) than those in CEAP(1-2) (P =.024); mean velocity in those in CEAP(3-6) during the first second of reflux was twice that of those in CEAP(1-2) (P <.0001); both higher volume flow and VV(outward) were found in the thigh perforators than those in the upper and middle calf thirds (P <.03); CEAP(3-6) volume flow and VV(outward), both in the first second, were twice that in those in CEAP(1-2) (P <.002); flow pulsatility in those in CEAP(5-6) was lower than in those in CEAP(1-2) (P =.014); in deep vein incompetence, higher peak velocity, volume flow, VV(outward), and diameter occurred than in its absence (P <.01). CEAP designation correlated significantly with mean velocity and flow pulsatility, both in the first second (r = 0.3, P <.01). The flow direction pattern in perforator incompetence was uniform across the CVI spectrum: inward on distal manual limb compression, and outward on its release; competent perforators had a smaller percentage of outward flow on limb compression (P <.01).

CONCLUSION

In addition to an increase in diameter, perforator incompetence is characterized by significantly higher mean and peak flow velocities, volume flow, and venous volume displaced outward, and a lower flow pulsatility. Differences in early reflux enable a better hemodynamic stratification of incompetent perforators in CVI classes. In the presence of deep reflux, incompetent perforators sustain further hemodynamic impairment. In situ hemodynamics enable quantification of the function of perforators and can be used in the identification of the clinically relevant perforators and the impact of surgery.

Carotid plaque echogenicity and types of silent CT-brain infarcts. Is there an association in patients with asymptomatic carotid stenosis?

BACKGROUND

The aim of this study was to identify the differences in echogenicity and the degree of stenosis of asymptomatic carotid plaques associated with different types of ipsilateral silent CT-brain infarcts.

METHODS

Some 273 asymptomatic carotid plaques (218 patients) causing 50 to 99% stenosis were studied with high-resolution ultrasound. B-mode images were digitised and normalised by assigning certain grey values to blood and adventitia. The grey scale median (GSM) of the plaque in the normalised image was used to quantify echogenicity. Every patient had a CT-brain scan which an independent neuroradiologist read. The presence of 1) non-lacunar and 2) lacunar silent CT-brain infarcts ipsilateral to the carotid plaque was noted.

RESULTS

The mean GSM of plaques associated with non-lacunar silent CT-brain infarcts was 19.6, of plaques associated with lacunar infarcts was 35.5 and of those associated with no infarcts was 32 (p=0.008, ANOVA). The mean degree of stenosis was 79%, 72% and 73% respectively (p = 0.1, ANOVA). Plaque echogenicity (p = 0.007) and not the degree of stenosis (p = 0.07) predicted the presence of non-lacunar silent CT-brain infarcts (logistic regression).

CONCLUSIONS

Carotid bifurcation plaques, which are associated with non-lacunar silent CT-brain infarcts, are significantly more hypoechoic than those associated with lacunar or no infarcts. Plaques associated with lacunar silent infarcts and no infarcts have the same echogenicity and degree of stenosis. These findings suggest an embologenic mechanism of non-lacunar silent CT-brain infarcts that may have prognostic implications in patients with asymptomatic carotid stenosis. Prospective studies of asymptomatic carotid stenosis should assess the significance of 1) plaque echogenicity and 2) the presence of different types of silent CT-brain infarcts and atheroembolic stroke.

Types of neurovascular symptoms and carotid plaque ultrasonic textural characteristics

The aim of this study was to identify the echo morphology and stenosis of carotid plaques that corresponded to ipsilateral asymptomatic status, amaurosis fugax, hemispheric transient ischemic attack, and stroke. One hundred ninety-two plaques (150 patients), producing stenosis in the range of 50% to 99% and associated with various neurovascular manifestations, were studied. These plaques were imaged on duplex scans, and a series of textural features was produced in a computer to distinguish quantitatively their various echo patterns. Amaurosis fugax corresponded to dark, severely stenosed atheromas (90%); hemispheric transient ischemic attack and stroke corresponded to plaques with intermediate echoic characteristics and intermediate stenosis (80%); and asymptomatic status corresponded to bright, moderately stenosed plaques (70%; P < .05). The significance of these findings is discussed.

Effects of intermittent pneumatic compression of the calf and thigh on arterial calf inflow: a study of normals, claudicants, and grafted arteriopaths

BACKGROUND

Recent data indicate that intermittent pneumatic compression (IPC) of the foot may offer benefits in patients with intermittent claudication exceeding those of standard medications approved by the Food and Drug Administration. IPC of the foot (IPC(foot)) and calf (IPC(calf)) increases flow velocity in infrainguinal arterial bypass grafts and thus may prevent arterial thrombosis. Our aim was to evaluate the acute effects of IPC of the thigh (IPC(thigh)), IPC(calf), and IPC of the thigh and calf (IPC(calf + thigh)) in healthy controls, claudicants, and arteriopaths who have undergone infrainguinal bypass grafting for critical or subcritical limb ischemia.

METHODS

Sixteen limbs of normals (group A), 17 limbs of claudicants (group B), and 16 limbs of arteriopaths (group C) who had undergone infrainguinal autologous revascularization were studied. Blood flow was measured in the limbs of normals and claudicants in the popliteal artery and in the grafts of revascularized limbs by using duplex ultrasonography. Mean velocity (mV), peak systolic velocity, end diastolic velocity (EDV), pulsatility index (PI), and volume flow (Q) were measured in the sitting position at rest and within 10 seconds from the delivery of IPC(thigh), IPC(calf), and IPC(calf + thigh), IPC was delivered at maximum inflation and deflation pressures of 120 mm Hg and 0 mm Hg, respectively; inflation and deflation times of 4 and 16 seconds, respectively; and a proximal inflate delay of 1 second (calf compression preceding that of thigh).

RESULTS

In all 3 groups with all IPC modes, the Q, mV, and EDV increased while PI decreased (P <.05). IPC(thigh) was less effective than IPC(calf), but still increased Q (by 114%, 57%, and 59.8% in groups A, B, and C, respectively) and EDV, while decreasing PI in all 3 groups (P <.05). IPC(calf + thigh) was the most efficient mode, generating an increase in the median Q of 424% in controls, 229% in claudicants, and 317% in grafted arteriopaths. The addition of IPC(thigh) to IPC(calf) increased the mV and Q in group A (P < or = .044); the mV, Q, and EDV in group B (P < or = .03), and mV and PI by 24% and -27% in group C, respectively.

CONCLUSIONS

IPC applied to the thigh, either alone or in combination with IPC(calf), generates native arterial and infrainguinal autologous graft flow enhancement. The paucity of conservative methods available for lower limb blood flow augmentation may allow IPC of the lower limb to emerge as a reliable, noninvasive therapeutic option, ameliorating claudication and assisting infrainguinal bypass graft flow. IPC(thigh) adds to the armamentarium of currently known IPC options (foot or calf) promoting its applicability and efficacy.

Patterns of brain computed tomography infarction and carotid plaque echogenicity

PURPOSE

It was suggested that in the absence of cardioembolism the discrete subcortical and cortical infarctions on brain computed tomography (CT) are most likely associated with carotid atheroma, whereas the hemodynamic infarctions, diffuse widespread white matter lesions, lacunae and basal ganglia infarctions are most likely associated with other pathologic conditions. The aim of this study was to determine the ultrasonic characteristics of carotid plaques and the degree of stenosis that were associated with the different brain CT infarction patterns and normal CT (pattern A, discrete subcortical and cortical infarctions; pattern B, hemodynamic infarctions, diffuse widespread white matter lesions, lacunae and basal ganglia infarctions).

METHODS

Four hundred nineteen carotid plaques (315 patients), producing 50% to 99% stenosis on duplex scanning, were studied. These plaques were imaged on duplex scanning, captured, digitized, and normalized (standardized) in a computer. Subsequently, their gray scale median (GSM) was evaluated to distinguish quantitatively the hypoechoic (low GSM) from the hyperechoic (high GSM) plaques. The brain CT infarction patterns of A, B, or normal CT on the ipsilateral hemisphere were noted.

RESULTS

The pattern A brain CT infarction was associated with carotid plaques having median GSM of 11 and median degree of stenosis of 80%, as contrasted with pattern B (median GSM, 28.5; median degree of stenosis, 75%) or normal CT (median GSM, 22; median degree of stenosis, 75%) (Kruskal-Wallis test, P <.001 for the GSM and P =.002 for the degree of stenosis). In the logistic regression analysis only the GSM and not the degree of stenosis distinguished the plaques associated with the three CT patterns.

CONCLUSIONS

The pattern A brain CT infarction was associated with hypoechoic plaques suggesting an involvement of extracranial carotid artery embolization, whereas the pattern B was associated with hyperechoic plaques suggesting an involvement of other mechanisms (hemodynamic, intracranial small and large vessel disease).

The genesis of atherosclerosis and risk factors: a review

Atherosclerosis constitutes the most common medical and surgical problem. This can be manifested clinically as stroke, coronary artery disease, or peripheral vascular disease. In the present review the microscopic appearance of the normal arterial wall, the definition of atherosclerosis and the five theories of atherogenesis are described. These are: the lipid theory, the hemodynamic theory, the fibrin incrustation theory, the nonspecific mesenchymal hypothesis and the response to injury hypothesis. Based on the above theories the sequence of events in atherogenesis is analyzed. The classification of the atherosclerotic lesions according to Stary (types I-VI) and their characteristics appear in a table. The epidemiology and the role of the following risk factors are presented in detail: age, sex, lipid abnormalities, cigarette smoking, hypertension, diabetes mellitus, physical inactivity, alcohol consumption, obesity, and hemostatic factors. In addition, less common genetically determined associations like homocystinuria, Tangier disease, Hutchinson-Gilford syndrome (progeria), Werner's syndrome, radiation induced atherosclerosis and the implications of Chlamydia pneumoniae on the arterial wall are discussed.