Diameter and compliance of the greater saphenous vein - effect of age and nitroglycerine.

OBJECTIVES: The greater saphenous vein (GSV) is commonly used in autologous vein graft surgery. GSV diameter has proven to influence graft patency, and furthermore venous compliance might be of importance. The purpose of the study was to evaluate the effect of age on GSV diameter and compliance, and to evaluate the effect of nitroglycerine (NTG). METHODS: The diameter and compliance of the GSV, with and without NTG, were examined with B-mode ultrasound in 12 elderly (70·3 ± 1·2 year) and 15 young (25·1 ± 0·6 year) men. The GSV diameter at the thigh and calf level was measured at rest, after 6 min of venous stasis (60 mmHg) and after NTG administration. Pressure-area curves during a linear venous pressure decrease were produced. Venous compliance was calculated using the quadratic regression equation (area) = ß(0) + ß(1) (cuff pressure) + ß(2) (cuff pressure)(2) . RESULTS: GVS diameter between the groups showed significant lower diameter in elderly compared to young men (P<0·05). Venous occlusion increased GSV diameter in elderly men (P<0·01) as well as young men (P<0·001). NTG increased GSV diameter in elderly men (P<0·01) with an equal trend in young men. During venous occlusion, after administration of NTG, GSV diameter increased further in both elderly (P<0·01) and young men (P<0·001). GSV compliance was decreased in elderly (ß(1) , 0·037 ± 0019, ß(2,) -0·000064 ± 00017) versus young men (ß(1) , 0·128 ± 0·013, ß(2) , -0·00010 ± 000018) [P<0·001 (ß(1) ), P<0·02 (ß(2) )]. CONCLUSIONS: Baseline GSV diameter as well as GSV compliance is decreased in elderly men compared to the young subjects. As reduced GSV diameter as well as reduced compliance is related to decreased graft patency, these findings might be of importance for the uses of GSV as graft material in cardiovascular bypass surgery. The clinical value has to be clarified in future studies.

Lower capacitance response and capillary fluid absorption in women to defend central blood volume in response to acute hypovolemic circulatory stress.

Acute hemorrhage is a leading cause of death in trauma, and women are more susceptible to hypovolemic circulatory stress than men. The mechanisms underlying the susceptibility are not clear, however. The aim of the present study was to examine the compensatory mechanisms to defend central blood volume during experimental hypovolemia in women and men. Twenty-two women (23.1 +/- 0.4 yr) and 16 men (23.2 +/- 0.5 yr) were included. A lower body negative pressure (LBNP) of 11-44 mmHg induced experimental hypovolemic circulatory stress. The volumetric technique was used to assess the capacitance response (redistribution of peripheral venous blood to the central circulation) as well as to assess net capillary fluid transfer from tissue to blood in the arm. Plasma norepinephrine (NE) and forearm blood flow were measured before and during hypovolemia, and forearm vascular resistance (FVR) was calculated. LBNP created comparable hypovolemia in women and men. FVR increased less in women during hypovolemic stress, and no association between plasma NE and FVR was seen in women (R(2) = 0.01, not significant), in contrast to men (R(2) = 0.59, P < 0.05). Women demonstrated a good initial capacitance response, but this was not maintained with time, in contrast to men [e.g., decreased by 24 +/- 4% (women) vs. 4 +/- 5% (men), LBNP of 44 mmHg, P < 0.01], and net capillary fluid absorption from tissue to blood was lower in women (0.086 +/- 0.007 vs. 0.115 +/- 0.011 ml.100 ml(-1).min(-1), P < 0.05). In conclusion, women showed impaired vasoconstriction, reduced capacitance response with time, and reduced capillary fluid absorption during acute hypovolemic circulatory stress, indicating less efficiency to defend central blood volume than men.

Sex-related effects on venous compliance and capillary filtration in the lower limb.

Recent studies in humans have suggested sex differences in venous compliance of the lower limb, with lower compliance in women. Capillary fluid filtration could, however, be a confounder in the evaluation of venous compliance. The venous capacitance and capillary filtration response in the calves of 12 women (23.2 +/- 0.5 years) and 16 men (22.9 +/- 0.5 years) were studied during 8 min lower body negative pressure (LBNP) of 11, 22, and 44 mmHg. Calf venous compliance is dependent on pressure and was determined using the first derivative of a quadratic regression equation that described the capacitance-pressure relationship [compliance = beta1 + (2 x beta2 x transmural pressure)]. We found a lower venous compliance in women at low transmural pressures, and the venous capacitance in men was increased (P < 0.05). However, the difference in compliance between sexes was reduced and not seen at higher transmural pressures. Net capillary fluid filtration and capillary filtration coefficient (CFC) were greater in women than in men during LBNP (P < 0.05). Furthermore, calf volume increase (capacitance response + total capillary filtration) during LBNP was equivalent in both sexes. When total capillary filtration was not subtracted from the calf capacitance response in the calculation of venous compliance, the sex differences disappeared, emphasizing that venous compliance measurement should be corrected for the contribution of CFC.

Pericardiocentesis guided by 2-D echocardiography: the method of choice for treatment of pericardial effusion.

BACKGROUND: Percutaneous pericardiocentesis guided by 2-D echocardiography has been used at Linköping Heart Centre since 1983. AIM: To evaluate our experience of this method including a follow-up and also to determine the aetiology of pericardial effusion. METHODS: A retrospective study including 120 of 252 consecutive patients punctured. RESULTS: The two most common aetiologies were cardiac surgery (77% valve surgery), followed by malignant disease. The postsurgical effusions became clinically important a median of 12 days after surgery (range 0-56 days). The median survival in the group with malignant disease was 89 days (30-day survival 87%, 1-year survival 10%). Indwelling catheter was used in 93% of the patients. There was no mortality but one patient needed a second pericardiocentesis after an accidental puncture of the right ventricle. Nine patients had rhythm aberrations. Recurring effusion that needed puncture was seen in 8%. CONCLUSION: Pericardiocentesis guided by 2-D echocardiography is a safe and efficient method to treat pericardial effusion and also valuable as palliative treatment for patients with malignant aetiology of the effusion.

[Endoscopic B-mode ultrasonography in the diagnosis of head-and-neck tumors]. / Endoskopische B-mode-Sonographie in der Diagnostik von Kopf- und Halstumoren.

Examination of 40 patients with malignant laryngeal and/or pharyngeal tumours shows the possibility of utilising endoscopic B-mode-sonography in ENT. The currently available devices enhance diagnostic certainty of the established radiographic methods only in cases involving oropharyngeal or certain recurrent tumours and blood vessel infiltration. The pros and cons of endoscopic ultrasonography as well as case studies are discussed.