G.S. Makin

Assessment of wall structure and composition of varicose veins with reference to collagen, elastin and smooth muscle content

OBJECTIVES To compare collagen, elastin and smooth muscle contents of varicose and control long saphenous veins. DESIGN Collagen, elastin and muscle were estimated stereologically using random sampling and histological staining. MATERIALS Varicose vein samples were collected from nine patients (mean age 52 years, range 34-64 years) undergoing vein stripping, sample sites being saphenofemoral junction and knee. Control samples were taken from five patients (mean age 58 years, range 38-76 years) presenting for femoral-popliteal bypass at equivalent levels. METHODS Veins were fixed, sectioned transversely, and stained with Picric Acid Sirius Red. Analysis of samples was performed using point and intersection counting on vertically projected images. RESULTS Using two way analysis of variance tests, varicose saphenous veins had significantly larger wall areas (p < 0.01) and higher amounts of collagen (p < 0.01). Collagen content and wall area were significantly larger proximally compared to distally in both control and varicose veins (p < 0.05) with a higher content of smooth muscle and elastin in varicose veins proximally compared to distally (p < 0.05). There was no difference in wall thickness or elastin content between the two groups. CONCLUSIONS This suggests that varicose veins are a dynamic response to venous hypertension and are not thin walled structures as previously thought.

Tissue plasminogen activator in peripheral arterial thrombolysis

Thirty acute peripheral arterial thromboses in 28 patients were treated with local low‐dose intra‐arterial recombinant tissue plasminogen activator (t‐PA). All patients received 0·5 mg h−1 t‐PAand 15 also received 250 units h−1 of intra‐arterial heparin. Overall limb salvage at 30 days was 83 per cent (25 out of 30 limbs). Mean(s.d.) ankle/brachial index was increased by 0·53(0·26) and there was no significant difference between the group receiving t‐PA alone and that receiving t‐PA and heparin. No strokes or major haemorrhages occurred but there were four (13 per cent) minor haematomas associated with the catheter entry site. There were four (13 per cent) deaths from myocardial infarction occurring between 5 and 21 days after treatment. Rethrombosis occurred in four cases (13 per cent). In two patients following t‐PA alone, rethrombosis occurred after 2 and 11 days. Limb salvage was achieved with a successful repeat thrombolysis and a femoropopliteal graft respectively. Rethrombosis after t‐PA and heparin occurred after 30 days in two patients due to poor run‐off and extensive proximal atheromatous disease respectively. t‐FA is a safe, effective thrombolytic agent when given as a low‐dose intra‐arterial infusion. The addition of low‐dose heparin does not produce any significant benefit.

Do preoperative chlorhexidine baths reduce the risk of infection after vascular reconstruction

Pathogenic organisms are frequently present on the skin of vascular patients and are a risk factor for postoperative infection. A randomised trial of preoperative antiseptic baths was performed in 64 high risk vascular patients to determine whether two chlorhexidine baths could reduce the incidence of postoperative sepsis. Although pathogenic organisms were isolated preoperatively in 35% of patients, the wound infection rate after chlorhexidine baths (26%) was greater, though not significantly, than after baths with non-medicated soap (11%). An alternative theory that infection arises via lymphatics in the limb was not confirmed when organisms could not be isolated from groin lymph nodes in a group of 35 patients. The case for preoperative antiseptic regimes in vascular surgery remains unproven.

Intra-arterial thrombolysis using recombinant tissue plasminogen activator (r-TPA): The optimal agent, at the optimal dose?

Thirteen patients received 15 separate courses of intra-arterial (IA) r-TPA for acute and subacute peripheral arterial thromboses. Two patients received second courses: one following rethrombosis 2 weeks after the angioplasty of a residual stenosis, the other following rethrombosis 4 months after the initially successful thrombolysis. There were 10 men and 3 women with a mean age of 75.3 yrs (+/- 12.2). The median duration of ischaemia was 18 days (range 1-60), with five patients having severe ischaemia. All patients received IA r-TPA at a dose of 0.5 mg/h for a mean period of 26.2 hrs (+/- 12.6). Angiographic evidence of lysis was seen in all patients, however, this was insufficient to reperfuse the distal limb in two patients due to absence of run-off. Early rethrombosis occurred in both of these patients (less than 24 hrs, 11 days). There were no major complications, and minor groin haematomata occurred in four patients (three of whom underwent angioplasty). A further two patients rethrombosed despite angioplasty. One was successfully retreated and remains patent 5 months later, the other underwent surgical reconstruction. A partial systemic effect was confirmed by a reduction of plasminogen and fibrinogen to 66% of initial levels, and a reduction of alpha - 2-antiplasmin to 40% of initial levels. Haemoglobin was reduced by a mean 1.28 g/dl (+/- 0.82), however no transfusions were required, and no hypotensive periods occurred. Mean ankle/brachial systolic index (ABSI) was increased by 0.43 (+/- 0.24) overall.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute critical ischaemia of the limb: A prospective evaluation

A total of 119 patients with acute peripheral arterial ischaemia were studied prospectively to validate the definition of acute critical ischaemia suggested by the working party of the International Vascular Symposium. The majority of the patients had primary treatment using thrombolytic therapy. Overall limb salvage after 30 days was achieved in 56% of the patients, 19% required amputations and 25% died. Comparisons of the outcome in patients with or without a distal neurosensory deficit (limb salvage 30% vs. 72%, P = 0.0001) and those with absent or audible Doppler ankle blood flow (limb salvage 37% vs. 78%, P = 0.0001) confirmed that the severity of the initial ischaemia was a significant indicator of prognosis. The definition of acute critical ischaemia as assessed by objective measurement of Doppler pressures has been validated and can be used to divide patients into groups with critical and sub-critical ischaemia with different prognoses.

Prospective randomised comparative study of pulse spray and conventional local thrombolysis.

OBJECTIVES To compare the time required to achieve lysis with the pulse spray technique and the conventional slow continuous infusion technique. DESIGN Prospective randomised open Study. METHODS Eighteen patients suitable for intra-arterial thrombolytic therapy with conventional and pulse spray technique were randomised 1:1 to receive either pulse spray thrombolysis with 0.33 mg/ml rt-PA injected as a bolus of 0.2 ml or conventional thrombolysis with 0.05 mg/ml rt-PA infused at a rate of 10 ml/h. RESULTS The age, duration of symptoms, length of occlusion and prethrombolysis ankle brachial pressure index were comparable in the two groups. The median duration of thrombolytic therapy in the pulse spray group was 195 min (range 90-1260) compared to 1390 min (range 300-2400) in the Conventional group. The difference between the two groups was significant, p < 0.002 (Mann-Whitney test). CONCLUSIONS Significantly shorter time is required to achieve local thrombolysis with pulse spray compared to the conventional infusion method.

Screening for clinically unsuspected abdominal aortic aneurysms in patients with peripheral vascular disease

In patients with abdominal aortic aneurysms, most fatalities occur from rupture before the patient can be brought to hospital. Even when seen in hospital the mortality is still approximately 50% in contrast to elective repair which has a substantially reduced mortality of less than 5%. In order to reduce the number of patients dying from rupture, they must be diagnosed early to allow elective intervention, hence there has been considerable renewed interest in screening for abdominal aortic aneurysms. We have studied a consecutive series of 104 patients with either claudication or ischaemic rest pain in the lower limbs to determine the incidence of aortic aneurysms in this type of patient.

Carbon dioxide: An alternative to lodinated contrast media

OBJECTIVES To study the use of carbon dioxide as a contrast medium for arteriography. METHODS Carbon dioxide was used as a contrast medium for intra-arterial digital subtraction lower limb angiography in 12 examinations on 11 patients. RESULTS No complication was encountered and no significant changes occurred in the arterial pH, PaCO2 and PaO2. The quality of images as assessed by an independent observer was adequate for the majority of the vessels (77%). CONCLUSIONS Carbon dioxide is a safe alternative in patients at an increased risk of adverse reaction to iodinated ionic or non-ionic contrast medium and is very cheap.

Experience with pulse-spray technique in peripheral thrombolysis.

Pulse-spray thrombolysis (PST) is a new technique of accelerated peripheral arterial thrombolysis. This technique has been evaluated on 24 patients with limb ischaemia. Severe acute limb-threatening ischaemia with sensory and motor deficit was present in 11/24 (45.8%) patients. The median dose of recombinant tissue plasminogen activator (rt-PA) used was 18 mg (10-35 mg) injected in a concentration of 0.33 mg/ml and bolus size of 0.2 ml. The median length of occlusions treated was 23 cm (range 4-55 cm). Complete initial lysis was achieved in 23/24 (95.8%) and limb salvage at 30 days was achieved in 18/24 (75%) of the cases. The overall 30-days mortality was 4/24 (16.6%) and 2/4 (50%) in those who required surgical intervention. The median duration of thrombolytic treatment was 137.5 minutes (range 35-1125 minutes) which is an 11-fold and significant reduction (p < 0.001, Mann-Whitney) in lysis time compared with the results of conventional low dose infusion of rt-PA at a rate of 0.5 mg/h in 120 consecutive patients in our unit. PST rapidly restores vascular patency and may become the treatment of choice for acute limb ischaemia including those at immediate risk of irreversible ischaemic injury which would not be considered suitable for conventional thrombolysis.

Obesity as a risk factor in major reconstructive vascular surgery

In a prospective analysis of 150 consecutive major vascular reconstructions, 104 patients were of normal weight (NW), 33 were overweight (OW) and 13 were obese (OB), as defined by body mass index calculations (BMI = kg/m2). Wound infections were more common in OW than NW patients (10/33 versus 10/104, p < 0.01) and in the OB compared to the NW group (4/13 versus 10/104, p < 0.05). Wound dehiscence was more common in the combined OW and OB groups than the NW patients (3/46 versus 0/104, p < 0.01). Chest infections were more common in OB (4/13) than NW (9/104) patients (p < 0.02). Median (interquartile range) in-patient stay was longer in OB patients [34 (15-41) days] compared to OW [14 (10-19) days, p < 0.001] and NW [11 (8-15) days; p < 0.001] patients. Nonetheless, there were no significant differences in the rates of more major complications or operative mortality between the three groups and early infrainguinal graft patency and limb salvage rates were not different. Only one prosthetic graft infection occurred in this series. In conclusion, despite the higher risk of infective complications, major vascular reconstruction can be performed safely in overweight and obese patients.