Comparison of the Use of Arterial Doppler Waveform Classifications in Clinical Routine to Describe Lower Limb Flow.

BACKGROUND: Characterisation of arterial Doppler waveforms is a persistent problem and a source of confusion in clinical practice. Classifications have been proposed to address the problem but their efficacy in clinical practice is unknown. The aim of the present study was to compare the efficacy of the categorisation rate of Descotes and Cathignol, Spronk et al. and the simplified Saint-Bonnet classifications. METHODS: This is a multicentre prospective study where 130 patients attending a vascular arterial ultrasound were enrolled and Doppler waveform acquisition was performed at the common femoral, the popliteal, and the distal arteries at both sides. Experienced vascular specialists categorized these waveforms according to the three classifications. RESULTS: of 1033 Doppler waveforms, 793 (76.8%), 943 (91.3%) and 1014 (98.2%) waveforms could be categorized using Descotes and Cathignol, Spronk et al. and the simplified Saint-Bonnet classifications, respectively. Differences in categorisation between classifications were significant (Chi squared test, p < 0.0001). Of 19 waveforms uncategorized using the simplified Saint-Bonnet classification, 58% and 84% were not categorized using the Spronk et al. and Descotes and Cathignol classifications, respectively. CONCLUSIONS: The results of the present study suggest that the simplified Saint-Bonnet classification provides a superior categorisation rate when compared with Spronk et al. and Descotes and Cathignol classifications.

Statement for Doppler waveforms analysis.

Peripheral artery disease of the lower limbs (PAD) is a common disease. Evaluation of PAD is primarily based on non-invasive examinations with analysis of the arterial Doppler signal being a key element. However, the description of arterial Doppler waveforms morphologies varies considerably across medical schools and from country to country. In order to overcome this issue, the French College of Teachers for Vascular Medicine (Collège des Enseignants de Médecine Vasculaire; CEMV) has summarised the published data on Doppler waveforms analysis and proposes a new "Saint-Bonnet" classification system to describe Doppler waveforms morphologies. The simplified Saint-Bonnet classification comprises eight types and allows taking into account if the Doppler signal does not revert to baseline. This classification, which is based on previous classifications, could improve the descriptions of both physiological and pathological waveforms, recorded in lower limb arteries. According to the reviewed literature, recommendations about the use of Doppler waveforms are proposed. This statement is a preamble to reach an international consensus on the subject, which would standardize the description of arterial waveforms and improve the management of PAD patients.

A new method for the in vivo identification of mechanical properties in arteries from cine MRI images: theoretical framework and validation.

Quantifying the stiffness properties of soft tissues is essential for the diagnosis of many cardiovascular diseases such as atherosclerosis. In these pathologies it is widely agreed that the arterial wall stiffness is an indicator of vulnerability. The present paper focuses on the carotid artery and proposes a new inversion methodology for deriving the stiffness properties of the wall from cine-MRI (magnetic resonance imaging) data. We address this problem by setting-up a cost function defined as the distance between the modeled pixel signals and the measured ones. Minimizing this cost function yields the unknown stiffness properties of both the arterial wall and the surrounding tissues. The sensitivity of the identified properties to various sources of uncertainty is studied. Validation of the method is performed on a rubber phantom. The elastic modulus identified using the developed methodology lies within a mean error of 9.6%. It is then applied to two young healthy subjects as a proof of practical feasibility, with identified values of 625 kPa and 587 kPa for one of the carotid of each subject.

Carotid artery atherosclerosis and sleep disordered breathing in healthy elderly subjects: the Synapse cohort.

BACKGROUND: Sleep-disordered breathing (SDB) has emerged as an independent risk factor for carotid atherosclerosis (CA) and cerebrovascular disease in middle-aged subjects. Currently, there is no study providing a causal relationship between SDB and cerebrovascular lesions in elderly. OBJECTIVE: To assess the impact of SDB on CA in a cohort of healthy elderly subjects. METHODS: Seven hundred and fifty-five participants of a cross-sectional study on the association between SDB and cardiovascular morbidity, aged 68yr at study entry, were examined. All subjects underwent carotid ultrasonography and risk factors for atherosclerosis including smoking, metabolic syndrome and hypertension were examined. An apnea + hypopnea index (AHI)>15 was considered indicative of SDB. RESULTS: Presence of carotid lesion was found in 35% of the sample, predominantly in men and in overweight subjects. The most frequent alteration was arteriosclerosis present in 74% of cases, with stenosis >50% found in only 9% of subjects. No significant difference in the prevalence of carotid lesion was found between subjects with and without SDB, subjects with an AHI>30, even though, having a slight increase in CA. At the logistic regression analysis, male gender (p<0.001), systolic and diastolic blood pressure (p<0.001), dyslipidemia (p=0.003) and hypertension (p=0.009) were the variables independently associated with carotid lesions even in severe cases. CONCLUSION: The incidence of CA in healthy elderly subjects is mediated more by gender, metabolic factors and hypertension than by presence of SDB. Further clinical studies including extensive evaluation of all atherosclerotic factors are needed to elucidate the predisposing role of SDB for cerebrovascular risk.

In vivo velocity vector imaging and time-resolved strain rate measurements in the wall of blood vessels using MRI.

In this paper, we present a new approach for velocity vector imaging and time-resolved measurements of strain rates in the wall of human arteries using MRI and we prove its feasibility on two examples: in vitro on a phantom and in vivo on the carotid artery of a human subject. Results point out the promising potential of this approach for investigating the mechanics of arterial tissues in vivo.

Evaluation of the effects of compression stockings using venous plethysmography in persons with spinal cord injury.

BACKGROUND/OBJECTIVE: To examine the effect of graduated compression stockings (GCS) on the properties of the venous vascular system, as characterized by venous capacitance (VC) and venous outflow (VO), in the lower extremities of individuals with spinal cord injury (SCI), according to injury level. METHODS: Nine male subjects with SCI (5 with low paraplegia [LP], 4 with high paraplegia [HP]) performed 2 plethysmography tests: with and without graduated compression knee-length stockings (pressure of 21 mm/Hg). The VC, VO, and cardiovascular parameters (heart rate and blood pressure) were evaluated with and without GCS. RESULTS: The VC and VO were lower in patients with HP than in those with LP. For all subjects, VC was significantly lower (-14%) with GCS than without (1.77 +/- 1.18 vs 1.53 +/- 1.09 vol%, P < 0.01). On the contrary, VO did not differ significantly when wearing or not wearing GCS. CONCLUSIONS: This study demonstrated that 21-mm/Hg knee-length GCS are sufficient to prevent venous distension in individuals with SCI, even those with longstanding paraplegia, by significantly decreasing venous capacitance. This intervention may help to prevent deep vein thrombosis.

Post-varicella arteriopathy: benefits of using serial transcranial Doppler examinations.

A 2(8/12)-year old boy suffered from hemiplegia secondary to a post-varicella arteriopathy. His clinical status improved and after 4 years of follow-up he had no recurrent stroke or transient ischemic attack. Regular improvement of arterial lesions, demonstated by serial transcranial Doppler investigations, excluded a progressive arteriopathy. Aspirin therapy was initiated and continued during 2,5 years. Transcranial Doppler is a portable, non-invasive tool that can be easily used on a regular basis to follow-up children with post-varicella arteriopathy.

Superficial vein thrombosis: risk factors, diagnosis, and treatment.

Superficial vein thrombosis (SVT) risk factors are close to those of venous thromboembolism (VTE). Diagnosis is made in a clinical setting but ultrasonography is useful to eliminate concomitant deep vein thrombosis (DVT). For SVT of the lower limbs, which is the main location, varicose veins represent the principal cause but underlying conditions (e.g.: autoimmune diseases, malignancy or thrombophilia) must be sought in idiopathic, migrant or recurrent SVT and in the absence of varicose veins. Concomitant DVT and pulmonary embolism can occur in approximately 15% and 5% respectively. Historical treatments consist of anti-inflammatory agents plus elastic stockings and, in case of varicose veins, thrombectomy and stripping. Other treatments (anticoagulants, vein ligation) were assessed to limit the VTE risk. A one-month prophylactic dose of low molecular weight heparin plus elastic stockings could be the appropriate strategy in most cases. Other studies are needed before definitive conclusions can be drawn.