Search PubMed⌕ Search

Biomedical subjects

V C Roberts

Publications and source records attributed to V C Roberts.

At least 73 records · Page 4Linked to original sources
PubMed1979

Controlled trial of plasma exchange in treatment of Raynaud's syndrome.

Twenty-seven patients with Raynaud's syndrome had their digital vessel patency assessed by Doppler ultrasound after different thermal stresses. Digital vessel patency rates differed significantly after stresses at 15 degrees C and 45 degrees C. In a randomised controlled trial placebo and heparin had no effect either on patients' symptoms or on the patency of their digital vessels. Plasma exchange improved both symptoms and vessel patency rates at 15 degrees C and 21 degrees C. Improvement in seven out of eight of these patients has been maintained for six months. Assessing digital vessel patency by Doppler techniques allow continuous, atraumatic, and safe evaluation of the effects of different methods of treatment on the patency of the digital vessels and has helped to indicate that plasma exchange is a useful adjunct in the management of patients with severe Raynaud's syndrome.

Arteries↗
PubMed1979

Assessment of carotid artery stenosis using pulse wave transit time.

A prospective study has been undertaken on 24 patients to establish the relationship between the degree of internal carotid artery stenosis, as estimated by arteriography, and the pulse wave transit time in the carotid artery. The technique involves the simultaneous use of two continuous wave Doppler velocimeters, one on the carotid and one on the supraorbital artery, to measure the flow waves and hence deduce the pulse wave transit times. The measured transit times varied from 17 to 124 ms with a beat-to-beat variation of 11 per cent. The absolute transit time in any segment correlated moderately well with the estimated degree of stenosis (r = 0.68, P less than 0.001). However, normalization of the transit times, to correct for the effects of blood pressure and age, produced on improved correlation between the variables (r = 0.8, P less than 0.001). Normalization was achieved by dividing the common carotid to supraorbital transit time by the shortest transit time found between the common carotid and either the superficial temporal or brachial arteries. Significant differences in the normalized transit times were found between arteries that were diametrically stenosed by more than 50 per cent, by between 21 and 50 per cent and by 20 per cent or below. It is concluded that pulse wave transit time measurement can provide a simple and reproducible non-invasive technique for the diagnosis of varying degrees of carotid artery stenosis.

Adult↗
PubMed1979

Plasma exchange and Raynaud's phenomenon--its assessment by Doppler ultrasound velocimetry.

In a group of 47 patients with Raynaud's phenomenon, Doppler ultrasound velocimetry was used to establish the severity of the disease by detecting the patency of the digital arteries. In conjunction with small digital occlusion cuffs, digital artery systolic pressure was measured on either side of the finger. A significant variation in systolic pressure was detected in each finger, and on each side of individual fingers. A more sensitive index of the severity of the disease was noted when the digital systolic pressure was compared to the brachial systolic pressure. Plasma exchange, a potent method of lowering whole blood viscosity and plasma fibrinogen, was used to treat 18 of these patients. There was a significant improvement in digital vessel patency at both 21 degrees C and 13 degrees C after plasma exchange. Both the digital artery systolic pressure and the pressure index improved significantly after treatment.

Arteries↗
PubMed1979

Characterisation of post exercise pressure response curves in the pedal arteries of patients with peripheral vascular disease.

The response of the systolic pressure in the pedal arteries to the stress of exercise is one of several ways of assessing the severity of peripheral vascular disease. We have examined 2607 such pressure response curves in an attempt to produce a simple method of response classification. Regression analysis of the curves has shown that errors are least when the regression used is the same order as the number of data points. We conclude that post exercise response curves can be adequately classified from three data points, one obtained within two minutes of the cessation of exercise, a second obtained between 4 and 6 minutes from the end of exercise and a third taken 10 minutes after exercise. The use of a response curve indexed to systemic systolic pressure was not found to produce a better correlation between full and three point curves, though the absolute classification differed slightly from that obtained from the non-indexed curve. Neither classification system proved significantly superior in relating to the degree of arterial disease.

Arteries↗
PubMed1977

Electromagnetic blood flow measurement during extended deep femoral angioplasty.

Electromagnetic flow measurements have been made on 53 patients undergoing extended deep femoral angioplasty. Flow measurements were made on the common femoral artery before reconstruction, after reconstruction and following an intra-arterial injection of papaverine. Flow measurements were correlated with the clinical outcome of the operation. The follow-up period varied between 6 and 30 months. There was no significant difference in follow-up period between the success and failure groups. The operation produced a significant increase in volume flow in both the success and the failure group. Flow velocities before and after reconstruction were, however, significantly higher in the success group. The results indicate that flow velocity measurement is preferable to volume flow measurement in assessing the long-term success of extended deep femoral angioplasty. A flow velocity of less than 5 cm per second achieved after reconstruction is likely to lead to failure; more than 10 cm per second indicates the likelihood of success.

Arteriosclerosis↗
PubMed1975

Fibrinogen uptake scanning for diagnosis of deep vein thrombosis: a plea for standardization.

From an examination of the factors affecting the diagnostic accuracy of the 125I-fibrinogen test for detecting deep vein thrombosis it is concluded that there is a greater possibility of error if postoperative counts are referred to the preoperative baseline rather than counts made immediately after operation. A method is proposed for reducing other errors caused by instrument mishandling.

False Negative Reactions↗
PubMed1975

Failure of low-dose heparin to improve efficacy of peroperative intermittent calf compression in preventing postoperative deep vein thrombosis.

The possible benefits of adding a low-dose heparin regimen to the technique of peroperative intermittent calf compression for preventing deep vein thrombosis (D.V.T.) were assessed in a randomized trial in 84 surgical patients. The efficacy of peroperative intermittent calf compression was not enhanced by a low-dose heparin regimen, but neither was it worsened. Age, weight, duration, operation, and malignant disease did not affect the relative effectiveness of the two regimens of prophylaxis. The results confirmed that venous stasis is the principal cause of D.V.T.

Adult↗
PubMed1975

Extended deep femoral angioplasty: an alternative to femoropopliteal bypass.

The results of extended deep femoral angioplasty (EDFA) have been alaysed for 74 legs in 72 patients. In 69 per cent a femoropopliteal bypass would have been possible, so DEFA is considered here as an alternative operation. The success rate was 66-9 per cent, the failure rate 25-6 per cent and no effect was achieved in 7-5 per cent. Diabetes adversely affected the results. Of the failures, 45 per cent were diabetic, while the incidence of diabetes was only 14 per cent in the group where the operation was successful. The long term results of the operation were reasonable, 75 per cent being successful for 10-39 months. Age had no bearing on success or failure. The effects of EDFA were most dramatic on intermittent claudication. In 52 per cent it was abolished and in 92 per cent claudication distance was increased to over 200 yards. Good results were achieved after failed lumbar sympathectomy and failed femoropopliteal bypass. Successful results of EDFA could be predicted best by inspection of angiograms. Success or failure could have been predicted from the state of the run-off in 81 per cent of the cases. Claudication and rest pain were the most relieved by EDFA, followed by isachaemic ulceration of the leg. Gangrene of digits was helped but less than had been hoped. We conclude that the indications for femoropopliteal bypass are limited to cases of digital gangrene where angiography shows that bypass is possible or where an EDFA operation has failed.

Adult↗
PubMed1974

Prevention of postoperative deep vein thrombosis in patients with malignant disease.

We have used the (125)I-fibrinogen test to asses the value of an improved method of peroperative intermittent calf compression as a prophylactic measure against postoperative thrombosis. In a group of 99 patients over the age of 40 undergoing operations lasting more than 30 minutes the technique reduced the incidence of postoperative thrombosis by over 75%. In patients suffering from malignant disease, who are generally considered to be in the very high risk category, the reduction achieved was almost 90%.

Clinical Trials as Topic↗