Five-year vascular audit from a district hospital

The challenges of treating peripheral arterial disease

Today, peripheral arterial disease (PAD) patients need effective medical care for an extended period of their lifetime. Therefore, different treatment modalities have to be tied sequentially into an effective therapeutic chain. First, preventive measures have to be reinforced and risk factors tightly controlled. Furthermore, antiplatelet agents have to be applied in every PAD patient to reduce the risk of cardiac and cerebral ischemic events, restenosis or reocclusion after revascularization, and possibly also progression of the PAD itself. Angiotensin-converting enzyme (ACE) inhibitors should be entertained in high-risk groups such as PAD patients with diabetes. In the claudicant, exercise therapy should be strongly encouraged and vasoactive drugs considered for those who are not good candidates for either exercise training or revascularization. In patients with disabling claudication or critical limb ischemia, revascularization procedures are highly effective. Especially for high-grade stenoses or short arterial occlusions, percutaneous transluminal angioplasty (PTA) should be the method of fi rst choice followed by the best surgical procedure later on. To achieve good long-term effi cacy, a close follow-up including objective tests of both the arterial lesion and hemodynamic status, surveillance of secondary preventive measures and risk factor control is mandatory.

Marriage of resistance and conduit arteries breeds critical limb ischemia

Atherosclerosis in a major leg artery leads to impaired blood supply, which normally progresses to critical limb ischemia. Atherosclerosis produces substantial alterations of structure and endothelial function in the large conduit arteries. Pressure unloading and ischemia in the distal vasculature bring about alterations in microvascular function. Resistance arteries undergo significant wall thinning and changes in their contractile regulation. Optimization of large artery dimensions by the small arteries through flow-mediated vasodilation is impaired. Angiogenesis is stimulated, which can result in the formation of major collateral feeder vessels in addition to small nutritive blood vessels. However, angiogenesis can also contribute to instability of atherosclerotic plaques, which ultimately leads to further deterioration in blood supply. Surgical bypass grafting to restore blood supply to the distal leg generates a sudden increase of pressure in the weakened resistance vasculature, leading to uncontrolled changes in capillary hydrostatic pressure, extravasation of fluid, and tissue edema. This review aims to highlight the importance of the resistance vasculature in critical limb ischemia and the interdependence of pathophysiological changes in the large conduit and small resistance arteries. The major unresolved question is why the physiological mechanisms that regulate vascular structure and function ultimately break down, leading to circulatory failure within the distal limb.

Prostanoid drug therapy for peripheral arterial occlusive disease--the European experience

The most serious threat to a claudicant is not the possible future need for a major amputation, but rather that the medium-term mortality is two to three times that of the general age-matched population. In patients with more severe disease in the legs, approximately 45% will have had a major amputation or be dead within a year of developing rest pain, ulcers or gangrene. These are the challenges for pharmacotherapy in peripheral arterial occlusive disease. In the short and medium term, pharmacotherapy can only have a significant effect by modifying the microcirculatory response to the low perfusion pressure caused by the arterial disease. The microcirculatory changes in the leg in severe leg ischaemia are ill understood, but theoretically a number of pharmacological effects could be beneficial. In practice, the only type of drugs widely tested clinically in severe leg ischaemia are prostacyclin and its analogues. In the last 12 years the results of properly controlled randomized trials involving patients with chronic limb ischaemia have been carried out in approximately 2000 patients in Europe. The largest number were entered into trials using the prostacyclin analogue iloprost. Some of these trials have shown a significant benefit compared to placebo in terms of major amputation or death during the 6 months following a 2-4 week course of intravenous iloprost. The possible future indications for this type of therapy, as well as the use for prostaglandins in claudicants, is discussed.

District hospital management and outcome of critical lower limb ischaemia: comparison with national figures

OBJECTIVE

To compare local with national management and outcome of critical limb ischaemia (CLI).

DESIGN

Use of nationally identified management groups for allocation of local patients. These were: revascularisation, primary major amputation, medical/minor surgical treatment and no treatment.

MATERIAL

All admissions with CLI for the 5 year period January 1990 to December 1994.

RESULTS

Local compared to national revascularisation of 43% vs. 63%, primary major amputation of 18% vs. 16%, medical/minor surgical of 20% vs. 8% and no treatment of 19% vs. 13%. During the fifth year 59% of limbs were revascularised. Fewer patients died in hospital locally (8% vs. 14%), particularly the group having no treatment (9% vs. 44%), but by 6 months only 58% of this group had survival. Local compared to national hospital limb salvage of 76% vs. 68% and patency of revascularisation of 86% vs. 75%. Of the revascularisations a low rate of percutaneous transluminal angioplasty (PTA) was noted locally (16% vs. 34%) and more grafts were being taken to above-nee popliteal artery (26% vs. 13%). Crural grafts were revised to a secondary amputation in 42%.

CONCLUSION

Although differences were observed between local and national management of CLI, overall acceptable outcomes were being obtained locally despite there being an identifiable deficiency in the availability of radiological services with regard to urgent PTA and thrombolysis.

Early reoperation rates after arterial surgery

Between 1 January 1985 and 31 December 1991, 2426 patients underwent arterial surgery. Three hundred and seventy one reoperations were performed on 258 patients within 30 days of the initial procedure. One hundred and ninety three (52%) of the operations were attempted revascularisations, 95 (26%) were amputations and 58 (16%) were to control bleeding. One hundred and sixty nine (66%) of first operations were successful, but 76 patients required a further 113 reoperations. The mortality of reoperation was 16%, while the mortality of patients not requiring reoperation was 9% (p < 0.01). The mean hospital stay in days was higher in patients requiring reoperation (p < 0.05). Where appropriate, patients should be informed of the significant incidence of reoperation and reoperative mortality after vascular surgery. The increased hospital stay in reoperated patients has financial implications.

Femorocrural grafting and regrafting: does polytetrafluoroethylene have a role?

Between 1980 and 1988, 263 patients received 307 femorocrural bypass grafts. 180 were primary infrainguinal grafts, 106 secondary, 18 tertiary and three quaternary. Rest pain or tissue loss was the indication in 96% of cases. Outflow vessels were the tibioperoneal trunk (n = 34), posterior tibial artery (n = 115), peroneal artery (n = 89) and anterior tibial artery (n = 69). 88 primary vein grafts were completed. 201 polytetrafluoroethylene (PTFE) grafts were inserted (92 primary and 109 subsequent reconstructions). There were no direct PTFE to crural vessel anastomoses. A Miller cuff was used in the majority (n = 175). The three year primary patency for primary vein grafts (36%) was similar to primary PTFE grafts (29%), but significantly higher than subsequent PTFE grafts (20%) (p = 0.03). Three year foot salvage for primary vein grafts (65%) was similar to primary PTFE (64%), but significantly better than subsequent PTFE (42%) (p = 0.02). The results support both redo femorocrural grafting for critical ischaemia, as judged by foot salvage rates, and the use of PTFE with a distal vein cuff in primary and subsequent femorocrural reconstruction if autologous vein is not available.

The importance of vascular surgical audit to surgeons, patients and purchasers

This audit of vascular surgical operations from a Teaching Hospital vascular unit was facilitated by computerised data collection. A total of 2075 patients had 2628 procedures over the 6-year period 1985-1990. Vascular workload increased by 50% to almost 350 primary reconstructions per year. In Bristol, vascular patients now occupy 19% of surgical bed-days. Mean stay for vascular patients is twice as long as for general surgical patients (14 days vs. 6 days) and three times as long for patients having secondary reconstructions (18 days) or those with critical limb ischaemia (21 days). Mortality and reoperation rates remained relatively constant throughout the study period. The overall mortality rate was 10.4%, being highest for ruptured aortic aneurysms (31.9%) and lowest for carotid endarterectomy (1.7%). Early reoperation for the complications of vascular reconstruction was required in 9.1% cases, being most frequent for femoro-tibial grafts (26.1%) and least for carotid endarterectomy (1.7%). Vascular surgery is expensive, time consuming and on the increase in Bristol. Comprehensive computerised audit of vascular operating is essential both for patients who benefit from the maintenance of high standards, and also for surgeons whose results this year will determine the cost and volume of next year's contracts.