Estimation of intraoperative aortocoronary bypass saphenous vein graft circumference from its preoperative compliance.

The aim of this study was to determine if the intraoperative circumference of aortocoronary saphenous vein bypass grafts could be predicted from preoperative measurement with B-mode ultrasound sonography in 50 patients. The circumference of the saphenous vein was measured during stepwise increments of a thigh congestive cuff from 0 to 60 mmHg. The circumference of the corresponding segment of the coronary bypass vein graft was measured intraoperatively with callipers. The intraoperative circumference was higher (11.8+/-2.3 mm) than the preoperative circumference (10.2+/-2.4 mm, P=0.006) matched to its corresponding intraoperative mean arterial pressure (57+/-15 mmHg). The prediction of the intraoperative circumference by estimation from the preoperative pressure-circumference relationship fitted by a linear model (r = 0.412, P = 0.004) did not improve on the preoperative circumference matched by arterial pressure alone (r = 0.429, P = 0.003). The intraoperative circumference of the graft vein exceeded its preoperative circumference by 12%. Prediction of the intraoperative graft vein circumference is underestimated by a linear model of its preoperative compliance.

Acute middle cerebral artery stroke and transcranial Doppler sonography.

Five studies (Zanette et al., Stroke 1995;26:430-3; Pulci et al., JEMU 1991;12:190-5; Kuschner et al., Neurology 1991;41:109-13; Camerlingo et al., Acta Neurol Scand 1993;88:108-11; Kenton et al., Stroke 1997;28:1601-6) have validated the diagnostic and the prognostic value of Transcranial Doppler Sonography (TDS) at the onset of middle cerebral artery (MCA) strokes, but there is no large study and the interest of these investigations is often ignored. This report insists on the TDS methodological rules. It shows its value in the detection of MCA stenoses or occlusions (mainly from cardiac origin) and underlines its usefulness in evaluating therapeutical procedures and in defining hemodynamic consequences of tight internal carotid artery stenoses.

Calf vein compliance increases following bed rest after aortocoronary bypass surgery.

Early post-operative ambulation (< 3 days) is expected to decrease the risk of venous thrombosis, whereas late ambulation (> 7 days) increases the risk of orthostatic hypotension. The effect of post-operative bed rest on calf vein compliance was studied before (D - 1) and 7 days (D + 7) after aortocoronary bypass surgery in 50 patients (41 men and nine women, 65 +/- SD 10 years). Calf vein compliance was measured by strain gauge plethysmography and stepwise increases in thigh congestive pressure from 20 to 60 mmHg. Calf compliance [median (25 percentile-75 percentile)] increased significantly by 48% from D - 1 to D + 7 [0.044 (0.039-0.051) vs. 0.065 (0.048-0.083) ml (100 ml mmHg)-1, P < 0.001]. This increase was reflected as increased calf volume for the 50 mmHg [D-1 2.10 (1.75-2.65) vs. D + 7 2.60 (1.70-3.00) ml 100 ml-1, P < 0.01] and 60 mmHg [D - 1 2.50 (2.10-2.95) vs. D + 7 3.20 (2.30-4.00) ml 100 ml-1, P < 0.001] occlusion pressure levels. The associated pathologies (diabetes and arterial hypertension) and NYHA grades had no significant influence on the increase in compliance. Among the vasoactive therapeutic regimens, calcium channel blockers contributed significantly to the increased calf compliance, but only on D-1. The increase in venous compliance following aortocoronary bypass surgery is multifactorial but should be considered for prophylactic management of these patients.

[Isolated plantar venous thrombosis. Report of a case]. / Thrombose veineuse plantaire isolée. A propos d'un cas.

We report the case of a patient with isolated plantar thrombophlebitis as a post operative complication of saphenectomy. Risk factors such as prolonged bed rest, perioperative inflammation and surgery of the greater saphenous vein itself should be considered. Moreover multiple episodes of superficial venous thrombosis had already occurred as complication of the superficial venous insufficiency. Literature on this unusual outcome is lacking. Ultrasound imaging revealed this superficial thrombosis. Usual echographic signs (non compressible vein, hypoechogenicity of the vessel lumen) can be found. The main problem is to differentiate veins from adjacent tendinous structures. Slow mobilisation of the toes and comparative analysis on contralateral foot are helpful. Thrombosis of the plantar veins must be considered as a possible diagnosis of unexplained plantar unilateral pains. Development of ultrasonic investigations and knowledge of its occurrence could further improve its diagnosis.

Effects of positive pressure on both femoral venous and arterial blood velocities and the cutaneous microcirculation of the forefoot.

OBJECTIVE: The balance between the apparent beneficial effect and the risk of arterial ischaemia resulting from an external uniform compression is unclear. The purpose of this study was to determine the effects of a positive uniform compression on the lower limb circulation until a critical threshold was reached. METHODS: We used Doppler ultrasound to measure femoral venous and arterial blood velocities. The effects of positive pressure on cutaneous microcirculation were evaluated by laser Doppler flux (LDF), transcutaneous oxygen pressure (tcpO2) and transcutaneous carbon dioxide pressure (tcpCO2) on the forefoot of 17 healthy subjects. RESULTS: The results are expressed as median [lowest observed value-highest observed value]. Whereas the arterial femoral velocity (A.F.V.) decreased from 0.21 [0.08-0.36] to 0.17 [0.08-0.28] m s-1 for an external pressure as low as 10 mmHg (p < 0.001), the venous femoral velocity (V.F.V.) decreased from 0.13 [0.06-0.40] to 0.09 [0.05-0.34] m s-1 at 20 mmHg (p < 0.001). An increase of tcpCO2 from 39.8 [29.9-53.7] to 40.2 [30.0-55.5] mmHg (p < 0.05) and a decrease of LDF from 8.7 [3.1-25.9] to 5.5 [2.3-21.1] A.U. (p < 0.001) occurred at 10 mmHg. However, tcpO2 decreased only from 76.7 [40.2-91.2] to 64.6 [18.9-85.2] mmHg when the splint pressure reached 60 mmHg (p < 0.05). The observed parameters (LDF, tcpO2, V.F.V. and A.F.V.) decreased further (except for tcpCO2 which increased) up to the end of the study as the applied pressure was increased. CONCLUSION: Positive pressure on the full leg provided no significant beneficial effect on femoral venous blood velocity. Whereas we showed that for an external uniform pressure as low as 10 mmHg, significant impairments in both arterial inflow of the lower limb and microcirculation of the forefoot appeared in recumbent healthy young subjects.