[Linear insertion of atrioventricular valves (Livav): echocardiographic diagnosis, reliability and prevalence in the general population]. / Insertion linéaire des valves auriculoventriculaires (Ilvav): fiabilité du diagnostic échographique et prévalence dans une population sans trisomie 21.

OBJECTIVES: Assess the reliability of prenatal diagnosis of linear insertion of atrioventricular valves (Livav) by echocardiography as well as estimate Livav's prevalence in a population without Down syndrome. PATIENTS: One hundred and twenty-three fetuses of whom 113 were explored before and after birth and 631 consecutive out-patients explored in cardiopediatric unit. METHODS: Determination of the likehood ratio (LHR+ and LHR-) of Livav prenatal diagnosis. Evaluation of the consistency between pre- and postnatal diagnoses as well as between two observers after birth (Kappa index). Prevalence study according to the presence of Down syndrome, cardiac malformation or others abnormalities. RESULTS: LHR+ value was 6.17 and LHR- value was 0.30 for echographic Livav prenatal diagnosis. Consistency was low between pre- and postnatal diagnoses (Kappa = 0.57) and higher between two observers after birth (Kappa = 0.79). Livav prevalence was 2 to 5% in a population without Down syndrome but 15% when associated with a cardiac malformation. Seventy-eight percent Down syndromes had either Livav or AVSD. CONCLUSION: Livav echographic prenatal diagnosis is difficult, for it generates many false positives. Livav is not specific of Down syndrome and can be found relatively frequently in other subjects.

Cathodal current-induced vasodilation to single application and the amplified response to repeated application in humans rely on aspirin-sensitive mechanisms.

Assumed to rely on an axon reflex, the current-induced vasodilation (CIV) interferes with the microvascular response to iontophoretic drug delivery. Mechanisms resulting in CIV are likely different at the anode and at the cathode. While studies have been conducted to understand anodal CIV, little information is available on cathodal CIV. The present study investigates CIV observed following 0.1-mA cathodal applications on forearms of healthy volunteers and the possible mechanisms involved. Results are expressed in percentage of the cutaneous heat-induced maximal vascular conductance [%MVC (means +/- SE)]. 1) The amplitude of CIV was proportional to the duration of cathodal currents for periods of <1 min: r = 0.99. 2) Two current applications of 10 s, with 10-min interstimulation interval, induced a higher peak value of CIV (79.1 +/- 8.6% MVC) than the one obtained with all-at-once 20-s current application (39.5 +/- 4.3% MVC, P < 0.05). This amplified vascular response due to segmental application was observed for all tested interstimulation intervals (up to 40 min). 3) Two hours and 3 days following pretreatment with 1-g oral aspirin, the CIV observed following cathodal application, as well as the difference of cathodal CIV amplitude between all-at-once and segmented applications, were reduced. These findings suggest a role of prostaglandins, not only released from endothelial or smooth muscle cells, as direct vasodilator and/or as a sensitizer. Thus aspirin pretreatment could be used to decrease CIV resulting from all-at-once and repeated cathodal application and facilitate the study of the specific vascular effect induced by the drug delivered.

Transcutaneous oxygen pressure measurements (tcpO2) at ankle during exercise in arterial claudication.

AIM: Although a time consuming technique, tcpO2 provides complementary information as compared to other tests. Simultaneous recording of systemic and peripheral oxygen pressure changes with exercise could be interesting to confirm that local hypoxemia is of arterial origin, but accuracy versus gold standard arteriography and objectively determined cut-off points to be used in arterial claudication at the ankle are not reported. EXPERIMENTAL DESIGN: retrospective plus prospective study. SETTING: institutional practice, ambulatory care. PATIENTS: 100 patients suffering stage 2 claudication (group A) were retrospectively studied to objectively define cut-off points derived from tcpO2 recordings to be used in exercise testing. Then, applicability and reproducibility of these cut-off points were analysed prospectively in another 50 patients (group B). INTERVENTION: tcpO2 was measured on both calves and with a chest reference electrode. Arteriography on each side was quoted positive for a diameter stenosis superior to 75% or occlusion on the aorto-popliteal axis or of all-3-calf arteries. RESULTS: The best performance was obtained with tcpO2 changes from rest at the calf normalised to eventual chest changes (DROP) during or following the treadmill test. Optimal cut-off point determined through ROC curve analysis for DROP was -15 mmHg in group A. Applying this cut-off point in group B provided a 86/84% sensitivity/specificity and showed excellent reproducibility. CONCLUSIONS: TcpO2 measurement on the calf during exercise could be useful in a selected population of patients with claudication of questionable vascular origin and/or when other non-invasive investigations cannot be performed.

[Results of surgical treatment for renal artery dysplasia]. / Résultats de la prise en charge chirurgicale des dysplasies des artères rénales.

PURPOSES: To retrospectively assess functional results of surgical treatment for renal artery dysplasia. PATIENTS AND METHOD: From January 1992 to December 2001, 11 symptomatic patients including 9 women (mean age 47 years, range 23-67), underwent surgery for renal artery dysplasia. Three patients presented with normalized hypertension, three others presented with isolated systolic hypertension, and the five remaining presented with grade II or III hypertension. Angiograms showed evidence of dysplasia of 16 renal arteries. Six arteries showed stenosis (37.5%), four aneurysms (25%), four both (25%), and two arteries showed wall irregularities (12.5%). Endovascular revascularizations were performed in five patients (45%) during the treatment of six renal arteries (37.5%). All endovascular procedures were angioplasties without any stent placement. Six patients (55%) underwent conventional procedures (in situ or ex-situ surgery) for the treatment of seven renal arteries (44%). RESULTS: In the short term, the treatment had a significant decrease on the systolic arterial pressure (p=0.019) and in the number of drugs used (p=0.009), but was not significant in the diastolic arterial pressure (p=0.084). The benefits persisted after two years of follow-up (PAS, p=0.023, PAD, p=0.047, drugs p=0.03). Benefits persisted in all of the six patients who had had hypertension for less than five years. There was 60% functional failure in the treatment of the five patients with a more than five years history of hypertension. CONCLUSION: This study confirms the short and long term's beneficial results of the surgical treatment of symptomatic renal artery dysplasia. Rapid care of those patients should optimize the functional results.

[Endovascular treatment for obstructive disease of the aortoiliac bifurcation by the kissing stent technique]. / Traitement endovasculaire par "kissing stent" des lésions oblitérantes du carrefour aorto-iliaque.

PURPOSE: To evaluate short and medium-term results of endovascular repair of the aortoiliac bifurcation for occlusive disease by the kissing stent technique. METHOD: Twenty patients were included in this retrospective study between May 1999 and November 2002 (13 men, mean age 58 years, range 42-86). Fifteen were treated for bilateral common iliac artery stenosis (75%), four for unilateral common iliac artery occlusion with or without controlateral stenosis (20%), and one for bilateral common iliac artery occlusion (5%). Each patient had a clinical examination and dupplex-scan prior to discharge, at three months, twelve months then yearly. RESULTS: All procedures were successful. Forty balloon expandable stents were deployed in the kissing position (mean length and diameter, 45 mm and 9 mm). Nine other stents were also deployed either in the abdominal aorta (one patient) either in the lower portion of the common iliac artery. Intra-operative complications were represented by one hematoma of the groin region treated surgically, one emboli of the femoral bifurcation treated by Forgarty balloon embolectomy, three dissections of the common iliac arteries treated by stenting, and one internal iliac artery occlusion not treated. Mean follow-up was 21 months (range 3-36). Three significant restenoses (>50%) were diagnosed during this period and one patient had an additional transluminal procedure. No intra-stent occlusion was found. Primary and secondary cumulative patencies at 12 and 36 months were respectively 94.7%, 84,4% and 100%, 89%. CONCLUSION: We confirm the feasibility, and the reliability of endovascular aorto-iliac kissing stent reconstruction in occlusive disease for selected patients.

Reproducibility of proximal and distal transcutaneous oxygen pressure measurements during exercise in stage 2 arterial claudication.

AIM: Although transcutaneous oxygen pressure measurements (tcpO2) are largely used in the investigation of vascular patients, its reproducibility is still debated. Indeed an unpredictable gradient exists between arterial and transcutaneous oxygen pressure. We hypothesised that indices taking into account changes over time and independent of absolute starting values would be more reproducible than other indices. EXPERIMENTAL DESIGN: comparative test-retest procedure (1 to 13 days between tests). SETTINGS: institutional practice, ambulatory care. PATIENTS AND PARTICIPANTS: 15 subjects with stage 2 claudication. INTERVENTIONS: tcpO2 recordings at rest and at exercise during the 2 treadmill tests. MEASURES: calculation of the Delta-from-rest of oxygen pressure index (limb tcpO2 changes minus chest tcpO2 changes), of the resting - or minimal values attained during exercise - of absolute tcpO2 and of the regional perfusion index (regional perfusion index: ration of limb to chest). RESULTS: Both absolute tcpO2 and regional perfusion index at rest showed low reproducibility. During exercise the best reproducibility was attained through Delta-from-rest of oxygen pressure index calculation. Equations from the linear regression analysis (test 2 versus test 1) were 0.88 x -4.2 (r(2)=0.82) at the buttock level and 0.82 x -3.8 (r(2)=0.80) at the calf level. CONCLUSION: TcpO2 measurement on the calf or buttock during exercise, is a reproducible measurement in patients with vascular claudication, specifically when corrected for exercise-induced systemic pO2 changes trough Delta-from-rest of oxygen pressure calculation.

Prostaglandins participate in the late phase of the vascular response to acetylcholine iontophoresis in humans.

The participation of prostaglandins (PGs) in the cutaneous vasodilatation to acetylcholine (ACh) applied via iontophoresis is under debate. Using laser Doppler flowmetry, we studied the long lasting effect (20 min) of iontophoretic application (30 s; 0.1 mA) of ACh on the human forearm. Experiments were repeated (1) using deionized water instead of ACh to test the effect of current application, (2) after scopolamine treatment to inhibit muscarinic cholinergic receptors, and (3) 2 h, 3 days and 10 days following inhibition of PG synthesis with aspirin or a placebo control. Cutaneous vascular conductance (CVC) was calculated at rest (CVC(rest)), at peak vasodilatation in the first 5 min following ACh iontophoresis (CVC(peak)), and 20 min after iontophoresis (CVC(20)). The minimal CVC (CVC(min)) following iontophoresis was also determined. Cutaneous response to ACh displayed a biphasic pattern with an early and transient peak (CVC(peak): 62 +/- 8% of the maximal CVC induced by local heating (MVC)) followed by a long lasting slower vasodilatation (CVC(min): 44 +/- 6; CVC(20): 56 +/- 5%MVC). The current itself had no major effect. Scopolamine almost abolished both phases. The long lasting phase was aspirin sensitive but not the transient phase. At hour 2 post-aspirin, CVC(peak) was 61 +/- 10, CVC(min) 26 +/- 6 and CVC(20) 29 +/- 6%MVC. At day 3, CVC(peak) was 53 +/- 9, CVC(min) 22 +/- 3 and CVC(20) 25 +/- 4%MVC. At day 10, CVC(peak) was 67 +/- 10, CVC(min) 47 +/- 7 and CVC(20) 50 +/- 8%MVC. Placebo had no effect. We conclude that PGs participate in the vasodilator response following ACh iontophoresis. Previous non-steroidal anti-inflammatory drug treatments must be taken into account when studying the effect of ACh iontophoresis.

Anodal current intensities above 40 microA interfere with current-induced axon-reflex vasodilatation in human skin.

When using iontophoresis, the 'non-specific' vasodilatation (NSV) that is observed as a result of C-fibre excitation is generally attributed to the local accumulation of protons under the anode. NSV following prolonged 100-microA anodal current application only appears after the current is stopped. Break excitation alone does not explain the delayed onset of this vasodilatation. We hypothesised that this delay could result from an anodal block and thus, that a minimal intensity would be required to achieve hyperpolarisation of primary afferent fibres (mainly C-fibres). Using laser Doppler flowmetry, cutaneous blood flow was recorded in the forearms of 8 healthy volunteers 2 min before current application, during the application and 20 min after stopping the monopolar anodal current. In protocol 1, after 2.5 min of current application at an intensity of 100 microA, the intensity was abruptly decreased to 0-80 microA for a second 2.5-min period. The onset of vasodilatation was only delayed at intensities >30 microA during this second period. In protocol 2, re-application of the current after a 50-second interruption (expected to allow for the occurrence of an axon reflex) did not interfere with the onset of vasodilatation. Thus: (1) the minimal intensity interfering with the axon reflex is far lower than that reported for C-fibre blockade in isolated nerves; (2) the results suggest that current application does not directly interfere with the vasodilator mechanisms induced by the axon reflex at the level of smooth muscle cells.

Current-induced vasodilation during water iontophoresis (5 min, 0.10 mA) is delayed from current onset and involves aspirin sensitive mechanisms.

Study of the microcirculation by iontophoresis is potentially confounded by any non-specific effects of current application. Laser Doppler flow (LDF, mean +/- SD; arbitrary units; AU) was recorded on the forearms of healthy volunteers during and 20 min following application of 0.10-mA current for 1, 3 and 5 min, using deionised water as a vehicle. Local heating to 44 degrees C was then applied for 24 min to assess maximal vasodilation. Cathodal current applications resulted in delayed and prolonged vasodilation (peak values: 78 +/- 29, 75 +/- 19, 80 +/- 37 AU) whereas anodal peak LDF was 13 +/- 6, 27 +/- 34 and 72 +/- 40 AU for 1-, 3- and 5-min periods of current applications, respectively. From current onset, inflexion points in the responses to 3- and 5-min anodal current applications occurred at 4.5 and 6.5 min, respectively, and at approximately 1.5 min for all cathodal current applications. For 5-min current applications: a preliminary tourniquet ischaemia neither changed the time course nor the amplitude of the response to current application. In this situation, local anaesthesia abolished the current-induced vasodilation. Chronic capsaicin pretreatment decreased the amplitude of the vasodilation. Pretreatment with 500 mg oral aspirin decreased the cathodal vasodilation and abolished the anodal vasodilation, even in the absence of preliminary ischaemia. We conclude that vasodilation to prolonged application of 0.10-mA continuous monopolar current after transient tourniquet ischaemia cannot be exclusively the result of an axon reflex initiated by current onset. This current-induced vasodilation is at least partly dependent on capsaicin-sensitive afferent fibres and relies on aspirin-sensitive mechanisms at both polarities.