Upstream stenosis. Its diagnosis by Doppler signals from the femoral artery.

Transcutaneous femoral artery Doppler signals were measured with a 10-MHz pencil probe in 263 lower limbs of 135 patients. The Doppler waveforms were compared with arteriograms in 125 limbs with lower-limb ischemia and in 138 controls in the detection of minor (< 50%) and major (> 50%) iliac-artery stenosis. Doppler maximum velocity-time waveforms were obtained using a maximum frequency follower, and the wave-form shape was analyzed using a Laplace transform (LT) to produce a coefficient, the LT damping. Pulsatility index (PI) was also calculated. In 62 limbs with minor artery disease, mean LT damping was significantly greater than normal (0.5 +/- 0.15 vs 0.33 +/- 0.06; P < .001). In 63 limbs with major iliac stenosis, mean LT damping was higher still (0.78 +/- 0.16; P < .02). The LT damping was not affected by increased distal impedance and there was a good correlation with iliac stenosis in 65 limbs with an occluded superficial femoral artery (r = -0.73). The results with PI were inferior at every grade of severity of iliac disease when assessed by receiver-operator characteristic curves. These results suggest that LT damping is a sensitive method of analyzing femoral Doppler signals in the noninvasive detection of iliac artery stenosis.

A system for rapid analysis of the femoral blood velocity waveform at the bedside.

The shape of the arterial blood velocity waveform varies with atherosclerotic disease and several methods of quantifying the shape in order to predict the severity of the disease have been described. These methods include pulsatility index, the Laplace transform method, and principal component analysis. This paper describes the development of a system which allows the operator to acquire, display, and store waveforms from each limb and then to quantify the waveforms at the bedside within a few minutes. The system includes a 10 MHz bi-directional Doppler unit, an instantaneous mean frequency processor, and an Apple II microcomputer fitted with an accelerator card. Both the Laplace transform parameters and the pulsatility index are computed and each result is printed in tabular form together with the averaged results of five waveforms from each limb. The printout is suitable for inclusion in the patient's folder. In initial clinical studies Laplace transform analysis exhibited a good correlation with aorto-iliac stenosis as assessed angiographically (R = 0.73 P less than 0.001 t test).

Risk factors and transfusion requirements in aortic surgery.

An audit of heterologous blood usage was made on 169 of 185 successive patients undergoing aortic surgery with a view to identifying factors determining individual transfusion requirements. The use of knitted prostheses was associated with 1.4 units, and aneurysmal disease 1.0 units of extra transfusion. Other factors influencing extra transfusion requirements were presence of hypertension, diabetes mellitus and low preoperative haemoglobin values. Clearly, if appropriate, the use of woven grafts seems worthwhile in terms of reduced transfusion requirements. However, individual prediction of patient transfusion requirements does not appear feasible with the factors studied.

Monitoring arterial surgery: a comparison of pulse volume recording and electromagnetic flowmetering in aortofemoral reconstruction.

Intraoperative monitoring of aortofemoral reconstruction using Pulse Volume Recordings (PVR) and Doppler ankle systolic pressure indices (ASPI) is compared with volume blood flow obtained by electromagnetic flowmetering (EMF). Twenty-five patients aged 45-78 with limb ischaemia or abdominal aortic aneurysm were studied before and 20 minutes after reconstruction. Reconstruction of isolated iliac occlusions (25 limbs) produced immediate improvement in PVR results. PVR waveform pulsatility (upstroke time shortened; 249-183 msec, p = less than .001) was more sensitive than amplitude which was restored to pre-reconstruction levels (16.1 to 17.5 mm). Similar trends were seen in multisegment disease. PVR transit time was not as sensitive. EMFlow was increased in both groups (229-600 and 160-308 mls/min). ASPI was not useful. Both PVR amplitude and pulsatility were significantly correlated with EMF volume flow, but pulsatility was more sensitive and was a superior predictor of successful arterial revascularisation. Technical errors were detected and corrected, and 94% of grafts were patent on discharge. These results show a correlation between PVR pulse waveform shape and EMFlow to such an extent that PVR results may be taken as a useful indicator of successful arterial reconstruction.

Prostaglandin E1 infusion for small vessel arterial ischaemia.

The effects on severe arterial ischaemia of infusions of Prostaglandin E1 (PGE1) a vasodilator and inhibitor of platelet aggregation, were studied in 49 patients (aged 17-80). Criteria for patient selection included rest pain and/or digital ulceration and gangrene secondary to predominantly small vessel disease. PGE1 was infused at a low (6 ng/kg/min), intermediate (10 ng/kg/min) or high (14 ng/kg/min) dose rate via a central venous cannula on 52 occasions without serious side effects. Doppler studies, pulse volume recordings and infra red radiometry were used to quantify the clinical effects. Improvements in digital perfusion were demonstrated by increased pulse volume amplitude (7.1 +/- 1.1 to 21.6 +/- 2.7 mm mean +/- SEM) which remained significantly raised at 6 weeks (14.2 +/- 2.9 mm; P = less than 0.001 paired t test). Infra red digital temperatures were also significantly raised 6 weeks post infusion (27.2 +/- 0.6 degrees C to 29.5 +/- 0.6 degrees C; P less than 0.001). The majority of patients reported improvement in pain, and two thirds of 12 superficial ulcers healed in 6 weeks. These results show that PGE1, improves digital perfusion for several weeks in patients with severe arterial ischaemia.

Detection of arterial stenosis: increased accuracy using biplanar angiography and Doppler signal analysis.

Femoral artery Doppler signals were analysed from 68 patients with lower limb ischaemia undergoing biplanar angiography. These studies (pulsatility index, P.I. and LaPlace transform damping, LTD) were compared with clinical examination using this biplanar angiographic standard. Accuracy of femoral pulse palpation in predicting upstream stenosis was 67%. Biplanar angiography unmasked single plane stenosis underestimates in 21% of patients. In a subgroup of 39 lower limbs with aorto-iliac stenoses between 26 and 85% femoral LTD was the best predictor, being 84% accurate: whereas PI did not improve upon clinical examination. The need for biplanar angiography is underlined and the place of Doppler signal analysis in the assessment of arterial stenosis is confirmed.

Femoral artery doppler signal analysis in lower limb ischaemia.

The functional significance of the iliac artery stenosis was assessed non invasively using femoral artery Doppler signals and a new method of blood velocity waveform quantification. This mathematical analysis provided an index, the Laplace Transform Damping (LTD), which was compared with Pulsatility Index (PI) of 263 limbs, in patients with iliac occlusive atherosclerosis was demonstrated by arteriogram and in normal volunteers. Normal LTD results ranged from 0.26 to 0.43 with detection of minor iliac stenosis (less than 50%) at 0.51 (0.38 to 0.63) and major stenosis (greater than 50%) at 0.83 (0.55 to 0.99). LTD was not affected by raised distal impedance associated with superficial femoral artery (SFA) occlusion. PI however was poor at predicting the severity of iliac lesions in the presence of SFA occlusion. LTD and PI specificities and sensitivities were examined using receiver operator curves. At a value of 0.6 LTD was more sensitive than PI in separating major from minor iliac stenoses and at 0.4 LTD separated normals from the early disease group with a sensitivity of 81% and specificity of 88%. This preliminary experience with Laplace Transform Damping analysis suggests that it will improve the assessment of iliac stenosis especially in the presence of femoro-popliteal disease.

Management of penetrating injuries of the internal carotid artery.

Penetrating injury of the extracranial carotid arteries has until recently remained relatively uncommon, with some 250 cases being reported in the past 10 years. Internal carotid trauma represents approximately 20% of this total, and the management of these injuries high in the neck is controversial. Use of the Fogarty balloon catheter for control of distal retrograde bleeding is recommended.

Girth measurement is not a reliable investigation for the detection of intra-abdominal fluid.

Routine measurement of abdominal girth after suspected trauma is still recommended as a predictor of intraperitoneal bleeding but there is little evidence to support its accuracy. Girth measurements were taken on 12 recumbent adult patients by independent observers and repeated after infusion of 550 ml aliquots of dialysate to a maximum of 2000 ml. Girth increase per 500 ml infusion varied from -0.46 cm to 2.1 cm (mean 0.84 +/- 0.65 SD) giving a range in excess of 2.5 cm. In some cases the girth decreased after a further 500 ml infusion. A change in patient position altered the girth at a constant volume by 1.32 cm (+/- 0.75 SD). Observer error was low at 0.33 cm (+/- 0.35 SD). These results preclude girth as a reliable clinical indicator of intraperitoneal haemorrhage.

The acute abdomen: management with microcomputer aid.

This paper describes the management consequences of the use of a microcomputer as a special investigation in patients with an acute abdomen. Results in 812 patients seen by 42 junior doctors are compared six monthly and with baseline data from 295 cases from the preceding 2 years. Improvement in diagnostic ability from 48.5% to 71.8% (X2 = 25.8, P less than 0.001) resulted in a fall in negative appendicectomy from 37.5% to 9.71% (X2 = 16.2, P = less than 0.001). Bad management errors were also reduced from 22% to 10% (P = less than 0.01). The number of emergency investigation fell from 4 to 2 and inpatient stay of patients with non-surgical abdominal pain was reduced from 3 to 2 days. These results demonstrate that the use of microcomputers as investigative tools improves the surgical management of patients with acute abdominal pain.

Acute abdominal pain: computer aided diagnosis by non-medically qualified staff.

This report explores the role of computer aided diagnosis in acute abdominal pain when applied by non-medically qualified personnel. Clinical features of 153 patients (75 males, 78 females, aged range 6-92 years, median 35 years) suffering from less than one weeks' abdominal pain were recorded. Junior doctors' diagnostic accuracy with (65 cases) and without (70 cases) structured computer history sheets were compared with first year clinical medical students using the computer system (46 cases: 28 also seen by doctor, 18 cases student only). These students had no previous surgical training or experience. Doctors' diagnostic accuracy of 51% rose significantly to 69% with the use of structured history forms (chi 2 = 4.53, P = less than 0.05). Computer assisted clinical students' diagnostic accuracy matched the improved doctors' accuracy (69.5%). These results have implications not only for medical education but also for isolated paramedical personnel who should be supplied with structured diagnostic forms and, where appropriate, a microcomputer.

Below knee femoropopliteal bypass in severe ischaemia: results using EXS Dacron and human umbilical vein.

This paper reports our preliminary experience using EXS Dacron for infrageniculate femoropopliteal grafts in elderly patients, the majority (78%) suffering critical ischaemia. A comparison is made with human umbilical vein grafts (HUV). Ninety patients (mean age 69 years) with 92 grafts (42 EXS, 50 HUV) were followed up using ultrasound imaging to detect patency (median follow up 26 weeks (range 1-292)). Two and one year cumulative survivals were 57% and 80% for EXS Dacron and 39% and 48% for HUV respectively. Early failure of HUV grafts accounted for most but not all of the difference in survival (P = 0.0012, Wilcoxon Breslow). Graft kinking was not seen in EXS grafts and in only 2 HUV. Poor calf vessel run off was related to early graft occlusion (P = 0.01; Savage, Mantel Cox). This preliminary experience with EXS Dacron is encouraging and suggests the need for a formal randomised study.

Varicose vein surgery using a pneumatic tourniquet: reduced blood loss and improved cosmesis.

A prospective controlled randomised study has been performed of 100 consecutive patients undergoing varicose vein surgery. One group underwent saphenofemoral flush ligation and multiple lower leg avulsions with the leg exsanguinated with a Rhys-Davies cuff, and ischaemia maintained with a pneumatic tourniquet. The other group underwent identical surgery but with a 30 degree head down tilt only. Blood loss was significantly less (13.5 +/- 12 ml vs 133 +/- 78 ml; P less than 0.01) and postoperative cosmesis was significantly improved in patients in the tourniquet group. Operating time was similar (27 +/- 11 min vs 30 +/- 13 min) in the two groups.

After surgery for breast cancer: which mode of surveillance?

Five hundred and ten women attending a specialized breast clinic for follow-up after surgery of early breast cancer (Stage I and II) have been studied. Recurrence was found most often (58%) in symptomatic women who returned to the clinic earlier than planned. Only 3% of asymptomatic patients had recurrent disease. It is concluded that counselling in symptoms of recurrent breast cancer would allow more efficient follow-up.

The role of pulsatility index in the clinical assessment of lower limb ischaemia.

The routine clinical use of pulsatility index (PI) in the quantitative assessment of Doppler blood velocity/time waveforms, was assessed in normals and in patients with leg ischaemia. Two thousand and five hundred common femoral artery waveforms were studied in 57 subjects (38 males, 19 females). PI values showed a mean variability of 17% in subjects in normal sinus rhythm (NSR) (range 4.1-13.2). In 17 patients in atrial fibrillation (AF) but with no clinical arterial disease, PI varied 26%. Variability was reduced, using a ten beat average, to 7.5% in NSR and 9% in AF. Rise in PI correlated well with increase in peripheral resistance (R = 0.82) but PI was poorly related to arterial stiffness (R = 0.50). Although PI was able to identify patients with proximal arterial narrowing it was unable to distinguish the severity of disease as assessed arteriographically minimum diameters (R = 0.30). From our observations we conclude that while PI has an established place in the assessment of peripheral arterial disease it must be applied with caution and averaging from ten heart beats is an essential manoeuvre. PI may prove to be a more reliable index for assessing distal rather than proximal disease.

Fractures of the neck of the humerus: a review of the late results.

Eighty patients with fractures of the proximal part of the humerus were reviewed not less than 18 months later. The severity of the fracture, the duration of initial rest in a sling and the duration of physiotherapy all independently affected the result. A total of 81 per cent had satisfactory results. The patients with undisplaced fractures had better results (94 per cent satisfactory), but spent longer before beginning physiotherapy which necessitated a longer course. Early active movements within the limits of pain and discomfort are suggested in order to improve the ultimate result.

Peripheral vascular disease: non-invasive physiological measurement.

The best results from arterial reconstructive operations are obtained by careful patient selection and meticulous operative techniques. Noninvasive physiological tests provide important objective measurements at all stages in the management of peripheral vascular disease. Current techniques will be outlined and discussed.

Inflow site: its effect on femoropopliteal and distal graft patency.

In a series of 245 vein grafts, results of 163 from the common femoral artery were compared with 82 from the proximal superficial femoral artery. Groups were comparable for risk factors, except that significantly more of the superficial femoral artery group were anastomosed to a single calf vessel (P less than 0.02). Early technical failure was similar in both groups (14 per cent common femoral artery, 12 per cent superficial femoral artery, P = n.s.). Cumulative life table patency rates at 1 and 3 years were 77 per cent and 72 per cent in common femoral artery grafts, and 80 per cent and 70 per cent in superficial femoral artery grafts (P = n.s.). Analysis of 92 veins in situ (65 common femoral artery and 27 superficial femoral artery) showed 1-year patency rates of 75 per cent in common femoral artery grafts and 79 per cent in superficial femoral artery grafts (P = n.s.). These results suggest that the proximal superficial femoral artery is a safe inflow site for distal bypasses.

Limitations of percutaneous transluminal angioplasty in the treatment of femoro-distal graft stenoses.

Non-invasive follow-up of 94 femoro-distal reconstructions has identified 14 graft related stenoses (4 proximal anastomotic, 4 intragraft and 7 distal anastomotic). Stenoses treated by percutaneous transluminal angioplasty (PTA) recurred by 6 months. Stenoses treated by surgical revision remained satisfactory with a mean follow-up of 13 months. In this series, formal surgical revision appears to be superior to PTA for the treatment of graft stenoses.