Femoral artery disease

Femoral

artery disease

The common femoral artery is the continuation of the external iliac artery, which changes name as it passes the inguinal ligament. The artery divides into the superficial and deep (profunda) femoral arteries (figure 1). The superficial artery is mainly a transport vessel to the below-knee muscles and has very few branches; when it passes out of the adductor canal behind the knee it becomes the popliteal artery. The deep femoral artery has numerous ’branches, which are potentially important collaterals when the superficial femoral artery is occluded. As an extremely rare anomaly, human beings can have a persistent sciatic artery, and in such cases the superficial femoral artery is often hypoplastic and localised to the thigh. In this review, we will discuss atherosclerotic occlusive disease of the femoral artery from a surgical viewpoint, the main focus being on patients with intermittent claudication. Critical limb ischaemia will be mentioned when appropriate.

Pathology The femoral artery is one of the commonest sites for atherosclerosis. Development of a stenosis leads to a reduction of pressure and blood flow. The stenosis has to be substantial to create a pressure drop-ie, an area reduction of at least 70%, which corresponds to a diameter decrease of 50%. The collateral circulation develops from the widening of pre-existing arteries and provides a parallel pathway for blood flow at the site of severe stenosis or occlusion. In the thigh, there is extensive collateral potential via branches

Department of Surgery, University Hospital, S-755 98 Uppsala, Sweden (Prof D Bergqvist MD, Dr S Karacagil PhD) Correspondence to: Prof David Bergqvist

from the deep femoral artery. This reserve capacity is the main reason why patients who develop chronic occlusion of the superficial femoral artery without affecting the deep femoral artery have either no symptoms or mild symptoms of intermittent claudication. The natural course of the atherosclerotic process in the femoral artery is a continuous

progression (figure 2), although symptoms often occur stepwise with deteriorations and improvements. As soon as the origin of the deep femoral artery is also stenosed, the symptoms worsen. Usually deep femoral artery stenosis is localised to its origin, but in patients with diabetes mellitus atherosclerosis is frequently extensive. Thus, critical limb ischaemia is rarely a consequence of isolated occlusion of the superficial femoral artery but does occur when the deep femoral artery is also affected or when there are stenoses and occlusions in the crural arteries.

Epidemiological aspects The prevalence of femoral artery disease is difficult to determine. Firstly, many individuals have symptomless atherosclerotic lesions. Secondly, the proportion of symptomatic patients with isolated femoral artery disease is not easy to estimate because angiography is seldom done unless there is an indication for intervention. Moreover, combined proximal (above the groin) or distal (crural arteries) atherosclerotic changes are common. Thirdly, in patients with critical limb ischaemia, angiography usually reveals extensive lesions both in the femoropopliteal and in the crural vessels. Fourthly, there are only a few population-based studies, and finally the use of angiography to characterise morphologically the arterial system is not possible in a population study. Nonetheless, there are some population-based studies in which prevalence of intermittent claudication has been estimated with questionnaires or clinical investigations.

Figure 1: Normal femoral artery Deep femoral artery with numerous branches and superficial transport vessel (left), colour duplex sonography showing normal femoral artery bifurcation (middle), and femoral bifurcation with flow velocities of less than 1 0 m/s (right).

773

Figure 2: Femoral artery stenosis (top left) with normal crural vessels (bottom) and stenosis at origin of deep femoral artery (right), the superficial being occluded at Its origin Prevalence increases with age, and there seems to be a male predominance,l although in the Edinburgh study men and women were equally affected when the data were corrected for age.2 Prevalence varies between 0-5% and 6-9% (table 1). These data may reflect true geographical differences but variations may arise because of the different time periods and age ranges in these studies. Additionally, there could have been methodological differences in criteria used to identify and define intermittent claudication.

Natural

history

Data from placebo groups in controlled trials can be used to show the natural history of intermittent claudication (see also panel). In the ketanserin claudication substudy investigation12 patients on ketanserin had a 28% greater walking distance than controls within 12 months. A similar increase in claudication distance after 6 months was reported by Lindgarde et al in their study of oxpentifylline (pentoxyphylline).13 In STIMS (Swedish Ticlopidine Multicentre Study),14 341 placebo-treated claudicants were

median of 5-6 years. The high incidence of myocardial infarction, stroke, transient ischaemic attack, and death in that study underscores the high risk of cardiovascular complications and mortality in patients with intermittent claudication. This finding was confirmed in the Whitehall Study, which had a much longer follow-up, although the entry criteria were much less strict because a questionnaire was used to identify subjects with intermittent claudication. is In the placebo group of the 1969 patients in the PACK study, followed for at least a year, annual mortality was 4-3 % .16 This poor survival is due to the high prevalence of coronary artery disease (CAD) in patients with lower limb ischaemia; many are symptom free but in a substantial proportion there is severe three-vessel disease. 17 The relative risk of death in patients with peripheral vascular disease is around 2 after 5 years and 2-5 after 10 years; about half the mortality is due to CAD.l0 In the placebo group of STIMS, 3-3% of the patients a year underwent some sort of lower extremity vascular surgery (unpublished)-both aorto-iliac and femoropopliteal lesions were included. By analysing patients with isolated superficial femoral artery disease, Cox et al18 found, using the life-table technique, that the risk for intervention was 11% at 5 years and 14% at 10 years. Primary amputation was done in 1-6%. Continuation of cigarette smoking after the onset of intermittent claudication leads to an increased risk of

followed for

a

Panel. Natural hI_.,

,-

’,," ’,,,,, .’"" ,

,h_,! -", "-’,tI"1 ,- ;-,’ isolated femoral artery )es)0tt concerned. On the other hands MMHoatBS generallsed atherosclerotic d!seaaeth <
,

,t

-’-

’"

,

M.,.

a-ni,i’that"the ’s,’.=,i fizz5

Data

are

for men

only.

Table 1: Intermittent claudication In studies

774

some

population-based

associated with poor prognosis

complications such as myocardial infarction and amputation. Moreover, after reconstructive surgery, continued smoking increases the risk of graft failure. A low ankle and toe blood pressure seems to be an additional risk factor for deterioration of the circulation, as does multiple arterial stenoses and diabetes mellitus. In claudicants with diabetes, a toe pressure of 40 mm Hg or less points to an increased risk of developing critical ischaemia. Anklebrachial pressure index seems to be a useful marker for cardiovascular risk; in the Malmö population study,19 total mortality, mortality from ischaemic heart disease, and cardiac event rate were significantly higher in men aged 68 years with an index below 0-9 than in an index of 0-9 or more. The morphological progression of atherosclerosis in the femoral artery was rarely studied before the advent of duplex ultrasonography. Whyman et apo found that femoral artery stenosis progressed to occlusion in 21% (9/43) of patients within a median of 13 weeks. This change occurred only in patients with a flow velocity rate of more than 3 (ratio of intrastenotic to prestenotic peak systolic velocity). Similar morphological natural history was reported by Walsh et al21 who used duplex and repeat angiography. Again, smoking was a significant risk factor.

Diagnosis and therapy In claudicants in whom neither reconstructive surgery

endovascular

treatment

is planned,

nor

thorough clinical

investigation with measurement of ankle pressure is enough. In patients with indications for intervention (disabling claudication or critical limb ischaemia), most centres use the combination of colour-coded duplex scanning and angiography. Most patients with isolated femoral lesions are treated conservatively-" Stop smoking and keep walking" .22 Physical training has long since been adopted as a treatment option in patients with intermittent claudication. The suggested beneficial effect has been claimed to depend on several factors, such as muscle adaptation to exercise with reduced blood flow, improved metabolic capacity, reduced blood viscosity, altered walking technique, fluctuations in tolerance to pain, and the knowledge that the pain in itself is not harmful. On the contrary, training does not seem to lead to

increased collateralisation or redistribution of the blood

rigid selection criteria of Radack and analysis of studies on the effects of training

flow. With the

Wyderski,23

an

intermittent claudication showed the beneficial effect of dynamic exercise, significantly increasing both pain-free and absolute walking distance. Another randomised study, which is too recent to have been included in the above analysis, confirmed that exercise increases the walking time in claudicants.24 Stepwise logistic regression analysis has shown that major daily exercise is associated with stable claudication.2s Pharmacological treatment to improve claudication distance is controversial, a large number of drugs having been assessed.26 One difficulty is study design. For example, one of the most extensively studied drugs is oxpentifylline, but investigations have varied so much that reliable conclusions cannot be drawn23,26,27 The placebocontrolled trials of drug therapy are mostly small and the results contradictory; the increase in walking distance seems to be at most marginal. However, an important beneficial effect of antiplatelet drugs is prevention of cerebrovascular and myocardial ischaemic events,

on

including mortality. There are also strikingly few randomised studies to assess invasive treatment such as reconstructive surgery or intraluminal percutaneous techniques. Moreover, investigations are often focused on the technique itself and it is only exceptionally possible to isolate results on patients with femoral artery disease. In the absence of randomised studies, the use of decision analysis may be of value.28

Reconstructive vascular surgery Critical limb ischaemia is the main indication for infrainguinal bypass grafting to the popliteal artery in limbs with atherosclerotic femoral artery disease. Femoropopliteal bypass surgery in patients with intermittent claudication should be restricted to patients who continue to have severe disabling claudication after 6 months of conservative treatment-about 20 % of patients undergoing reconstructive surgery below the groin.29 The operation is justified only in centres with enough experience to guarantee excellent long-term results. In many large series it is difficult to obtain separate analysis of results in claudicants undergoing

Figure 3: Femoral artery occlusion before (left) and after (right) reopening with percutaneous balloon angloplasty 775

Surveillance after Intervention

*Cumulative life-table patency rates; t crude patency rates. PTFE= Polytetrafluoroethylene; UV = umbilical vein; VACSG 141 = Veterans Administration Cooperative Study Group 141. Blank cells not assessed.

Table 2:

Patency rates of femoropopliteal patients with intermittent claudication

reconstruction in

femoropopliteal bypass grafting. Patency rates of some series are shown in table 2. In most surgical studies the results are given as graft patency. Although this measurement is important with respect to surgical technique, a more relevant endpoint for patients would have been a measurement of walking distance and (though difficult to determine) quality of life. Blankenstejn et al36 addressed this issue and calculated that, after 5 years, only 34% would have benefited from the surgical procedure. In most studies, including a few randomised trials, the best bypass material is autologous vein. In our opinion, patients with claudication, when the indication to operate is less urgent relative to critical limb ischaemia, should have the best available bypass materials. A more conservative approach is needed in patients without superficial veins. It seems to make no difference whether the bypass is done with the vein reversed or left in situ with cusp destruction. In the few series in which superficial femoral artery endarterectomy has been used, results are similar to those of conventional bypass techniques 37,38 However, these two methods have not been compared in randomised studies. Percutaneous transluminal angioplasty (PTA) (figure 3) Patency rate is better in patients with claudication than among those with critical limb ischaemia. As with reconstructive surgery, interest in PTA has focused on patency and not on quality of life. In the study by Krepel et al,39 90% of 164 PTA procedures in 129 patients were performed because of intermittent claudication. 139 treatments were successful (84%), and cumulative 5-year patency was 70%; the best results were achieved with short (< 2 cm), morphologically regular stenoses. There are two studies in which claudicants alone were included. Zeitler et al40 showed a 2-year patency of 82% if lesions were 12 cm or less, whereas Vroegindeweig et al4l found a 61 % patency at 1 year. In the study by Creasy et a142 claudicants were randomised to PTA or training. Walking distance was farther in the training group than in the PTA group, despite the increased ankle pressure in the PTA group. However, this study included a mixture of patients with femoropopliteal and aorto-iliac disease, and the sample size was small (36 patients). A larger study in which 100 patients with femoropopliteal disease were randomised to PTA and a control procedure revealed that PTA patients were more likely to need extra interventions because of deterioration. At 2 years the groups were indistinguishable in anklebrachial indices. Whether stent placement would improve results in the long term is doubtful, 44,45 and further prospective randomised studies are needed. 776

There are many reasons for failure after reconstruction of a femoral artery lesion; the various causes predominate during different periods after the procedure. The development of fibrotic stenoses in vein grafts, pseudointimal hyperplasia, and restenoses after PTA are well known, most frequently occurring during the first To haemodynamic graft failure year. prevent (haemodynamic deterioration without symptoms) it is essential to detect and treat such stenoses before occlusion and development of symptoms to improve patency. The best way to detect failing grafts is to screen patients with colour-coded duplex ultrasonography (figure 4). Optimum time intervals in a surveillance programme remain to be established but it seems reasonable to recommend investigations 1, 6, 12, 18, and 24 months after reconstruction.

Key clinical questions Clearly, controversies about epidemiological aspects and of atherosclerotic femoral artery disease have arisen because of the lack of conclusive studies. It is important that future studies use very strict criteria and definitions when describing patients, so that it might be possible to assess patients on morphological and symptomatic criteria as well as haemodynamically. We believe that more research needs to be focused on the following issues:

treatment

Population-based studies with strict morphological criteria based on angiography (which is difficult) or duplex scanning. Such an approach would be better than using data from selected series to define risk factors and natural history. This background is necessary to optimise design of interventional studies. The relevance of symptomless disease is unknown.

Prospective randomised controlled trials strategies:

to assess

optimum

treatment

Conservative versus active treatment (surgical reconstruction or percutaneous angioplasty). Percutaneous angioplasty versus surgical reconstruction. Percutaneous angioplasty with or without stent application. Is there a role for superficial femoral endarterectomy? Optimum strategy for post-interventional surveillance programmes. The effect of normovolaemic haemodilution in haemoconcentrated patients. Is there a place for pharmacological treatment? Are there any adjunctive measures to improve results of

interventions? New

policies for the use of percutaneous is an implication that indications for the There techniques. use of such techniques may be less strict than those for surgical interventions. Before acceptance of new treatment policies the results from controlled studies are of utmost importance. One difficulty is the rapid technological development of endovascular techniques, new modifications occurring almost continuously. . Evaluation of and how treatment can influence the quality of in life patients with intermittent claudication. We need adequate scales to assess quality of life in claudicants. Identification of patients with intermittent claudication where intervention might prevent progression to critical limb ischaemia. Patients with diabetes mellitus are of special interest in this respect. treatment

questionnaire on chest pain and intermittent claudicaton. Br J Prev 9 10

Figure 4: Graft stenosis at distal anastomosis of

femoropopliteal vein bypass High velocities (almost 3 m/s) indicate severe stenosis.

Conclusion Most patients with isolated femoral artery atherosclerosis will be claudicants. In many of these patients a thorough clinical investigation including ankle pressure measurement is often enough, perhaps with duplex scanning as well. Most of these patients should be treated conservatively with proper information about the disease. They are often relieved when they are told that the risk of developing gangrene is very low. The main message in conservative treatment is to quit smoking and to exercise. In some countries oxpentifylline is available but it is far from being a wonder drug-walking distance may improve slightly. For patients who are socially disabled and for whom conservative treatment has no effect, endovascular treatment with balloon angioplasty or surgical bypass are indicated. Supported by Swedish Medical Research Council 00759. We thank Dr Anne-Marie Lofberg, Department of Diagnostic Radiology, who kindly provided the angiograms.

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1976; 18: 104-18. 8

Rose G,

McCartney P, Reid DD.

Self-administration of a

Soc Med 1977; 31: 42-48. Hughson WG, Mann JI, Garrod A. Intermittent claudication: prevalence and risk factors. BMJ 1978; i: 1379-81. Leng GC, Fowkes FGR. The epidemiology of peripheral arterial

disease. Vasc Med Rev 1993; 4: 5-18. 11 Skau t, Jönsson B. Prevalence of symptomatic leg ischaemia in a Swedish community: an epidemiological study. Eur J Vasc Surg 1993; 7: 432-37. 12 PACK Claudication Substudy Investigators. Randomized placebocontrolled, double-blind trial of ketanserin in claudicants: changes in claudication distance and ankle systolic pressure. Circulation 1989; 80: 1544-48. 13 Lindgärde F, Jelnes R, Björkman H, et al. Conservative drug treatment in patients with moderately severe chronic occlusive peripheral arterial disese. Circulation 1989; 80: 1549-56. 14 Janzon L, Bergqvist D, Boberg J, Eriksson I,Lindgärde F, Persson G. Prevention of myocardial infarction and stroke in patients with intermittent claudication: effects of ticlopidine: results from STIMS, the Swedish Ticlopidine Multicentre Study. J Int Med 1990; 227: 301-08. 15 Smith GD, Shipley MJ, Rose G. Intermittent claudication, heart disease risk factors, and mortality. The Whitehall Study. Circulation 1990; 82: 1925-31. 16 Dormandy JA, Murray GD. The fate of the claudicant: a prospective study of 1696 claudicants. Eur J Vasc Surg 1991; 5: 131-33. 17 Hertzer NR, Bevan EG, Young JR. Coronary artery disease in peripheral vascular patients: a classification of 1000 coronary angiograms and results of surgical management. Ann Surg 1984; 199: 223. 18 Cox GS, Hertzer NR, Young JR, et al. Nonoperative treatment of superficial femoral artery disease: long-term follow-up. J Vasc Surg 1993; 17: 172-82. 19 Ögren M, Hedblad B, Jungquist G, Isacsson S-O, Lindell S-E, Janzon L. Low ankle-brachial pressure index in 68-year-old men: prevalence, risk factors and prognosis. Results from prospective population study "Men born in 1914" Malmö, Sweden. Eur J Vasc Surg 1993; 7: 500-06. 20 Whyman MR, Ruckley CV, Fowkes FGR. A prospective study of the natural history of femoropopliteal artery stenosis using duplex ultrasound. Eur J Vasc Surg 1993; 7: 444-47. 21 Walsh DB, Gilbertson JJ, Zwolak RM, et al. The natural histsory of superficial femoral artery stenoses. J Vasc Surg 1991; 14: 299-304. 22 Housley E. Treating claudication in five words. BMJ 1988; 296: 1483-84. 23 Radack K, Wyderski RJ. Conservative management of intermittent claudication. Ann Intern Med 1990; 113: 135-46. 24 Hiatt WR, Regensteiner JG, Hargenten ME, Wolfel EE, Brass EP. Benefit of exercise conditioning for patients with peripheral arterial disease. Circulation 1990; 81: 602-09. 25 Cronenwett J, Warner K, Zelenock G, et al. Intermittent claudication: current results of nonoperative treatment. Arch Surg 1984; 119: 430-36. 26 Bevan EG, Waller PC, Ramsay LE. Pharmacological approaches to the treatment of intermittent claudication. Drugs Ageing 1992; 2: 125-36. 27 Cameron HA, Waller PC, Ramsay LE. Drug treatment of intermittent claudication: a critical analysis of the methods and findings of published clinical trials 1965-1985. Br J Pharmacol 1988; 26: 569-76. 28 Troëng T, Bergqvist D, Janzon L, Jendteg S, Lindgren B. The choice of strategy in the treatment of intermittent claudication: a decision tree approach. Eur J Vasc Surg 1993; 7: 438-43. 29 Myhre HO. Is femoropopliteal bypass surgery indicated for treatment of intermittent claudication. Acta Chir Scand Suppl 1990; suppl 555: 39-42. 30 Yashar JJ, Thompson R, Burnard RJ, Weyman AK, Yashar J, Hopkins RW. Dacron vs vein for femoropopliteal arterial bypass: should the spahenous vein be spared? Arch Surg 1981; 116: 1037-40. 31 Cranley JJ, Hafner CD. Revascularization of the femoropopliteal arteries using saphenous vein, polytetrafluoroethylene, and umbilical vein grafts. Arch Surg 1982; 117: 1543-50. 32 Klimach O, Underwood CJ, Charlesworth D. Femoropopliteal bypass with a Goretex prosthesis: a long-term follow-up. Br J Surg 1984; 71: 821-24. 33 Sterpetti AV, Schultz RD, Feldhaus RJ, Peetz DJ. Seven-year experience with polytetrafluoroethylene as above-knee femoropopliteal bypass graft: is it worthwhile to preserve the autologous saphenous vein? J Vasc Surg 1985; 2: 907-12. 34 Veterans Administration Cooperative Study Group 141. Comparative evaluation of prosthetic, reversed, and in situ vein bypass grafts in distal popliteal and tibial-peroneal revascularization. Arch Surg 1988; 123: 434-38. 35 Quinones-Baldrich WJ, Prego AA, Ucelay-Gomez R, et al. Long-term results of infrainguinal revascularization with polytetrafluoroethylene: a ten-year experience. J Vasc Surg 1992; 16: 209-17.

777

36

Blankenstejn JD, van Vroonhoven TJMV. Consequences of failure of femoropopliteal grafts for claudication. Eur J Vasc Surg 1988; 2:

183-89. 37 Ouriel K, Smith CR, DeWeese JA. Endarterectomy for localized lesions of the superficial femoral artery at the adductor canal. J Vasc Surg 1986; 3: 531-34. 38 van der Hejden FHWM, Eikelboom BC, van Reedt Dortland RWH. Endarterectomy of the superficial femoral artery: a procedure worth reconsidering. Eur J Vasc Surg 1992; 6: 651-58. 39 Krepel VM, van Andel GJ, van Erp WFM, Breslau PJ. Percutaneous transluminal angioplasty of the femoropopliteal artery: initial and long-term results. Radiology 1985; 156: 325-28. 40 Zeitler E, Feng G, Oldendorf M, Richter EI, Ritter W, Seyferth W. Ergebnisse der perkutanen transluminalen Angioplastie. Herz 1989; 14: 22-28. 41 Vroegindeswig D, Kemper FJM, Teitelbeek AV, Buth J, Landman G. Recurrence of stenoses following balloon angioplasty and Simpson

Allocation of

resources

42

atherectomy of the femoropopliteal segment: a randomized comparative 1-year follow-up study using colour flow duplex. Eur J Vasc Surg 1992; 6: 164-71. Creasy TS, McMillan PJ, Fletcher EWL, Collin J, Morris PJ. Is percutaneous transluminal angioplasty better than exercise for claudication? Preliminary results from a prospective randomised trial. Eur J Vasc Surg 1990; 4: 135-40. Rij AM, Packer SGK, Morrison N. A randomized controlled study of percutaneous angioplasty for claudicants with femoropopliteal disease. J Cardiovasc Surg 1991; 32: 34. Sapoval MR, Long AL, Raynaud AC, Beyssen BM, Fiessinger J-N, Gauz J-C. Femoropopliteal stent placement: long-term results. Radiology 1992; 184: 833-39. Do BD, Triller J, Walpoth BH, Stirnemann P, Mahler F. A comparison study of self-expandable stents vs balloon angioplasty alone in femoropopliteal artery occlusions. Cardiovasc Intervent Radiol 1992; 15: 306-12.

43 Van

44

45

in intensive

care: a

transatlantic

perspective

Summary The USA and the UK have differed substantially in approaches to health care and especially in intensive care provision. We have compared the health care systems, clinical justification for intensive care, selection of patients likely to benefit from such care, and the performance of the systems. The differences are lessening. Both countries are moving away from clinical autonomy as the driving force of medical decision-making. There is increasing recognition that not all patients will benefit from intensive care and that the doctor’s obligation to the patient can be limited by constraints set by society. Lancet 1994; 343: 778-80

Introduction The health care system of the USA is the costliest per head of population in the world. The UK National Health Service (NHS) although it spends only about 35 % as much as the USA system, is also in financial difficulty.l The issue that unites health commentators all over the developed world is that health resources are finite. Nowhere is cost-consciousness more apparent than in the provision of intensive care services, the most expensive form of therapy in both human and physical terms. Intensive care should represent a balance between resources and likelihood of benefit to specific patients. In reality, it is subject to several conflicting pressures-technology that has developed without adequate assessment of efficacy ;2 physicians, patients, and families who want "everything done" without recognising when medical intervention is futile;3 and legal precedent, which lags behind medical practice and what

might be regarded as ethically acceptable.4 Intensive-care units (ICUs) use up to four times the resources of routine Pulmonary and Critical Care Medicine, Oregon Health Sciences University, Portland, Oregon, USA (M Osborne MD); and National Heart and Lung Institute, Royal Brompton National Heart & Lung Hospital, Fulham Road, London SW3 6NP, UK (T W Evans FRCP). Correspondence to: Dr Timothy W Evans 778

hospital care and are therefore increasingly under scrutiny.5 Different approaches to the provision of intensive care have evolved in the USA, which has a high percentage of ICU beds (7-11 %), and in the UK, which has one of the lowest ( 1-2 % ).6 It seems unlikely that both approaches are correct. These differences are to a certain extent culturally determined and

USA health The

ethical

are not

confined

to

intensive

care.

system principles of

care

autonomy, beneficence, nonmalficence, and justice drive medical decision-making in the USA.7 The USA gives autonomy to the individual rather than the community,8 perhaps partly because insurance pays most health care costs. These principles are strongly supported by widespread belief in the effectiveness of technology, and traditionally everything possible has been done for a patient, without consideration of cost. In the USA patients defer less to physicians for treatment decision-making than is customary in the UK, and aggressive approaches for potentially terminal illnesses are commonly requested.9 Both patients and health care providers believe in the "rule of rescue"-the powerful human proclivity to rescue a single identified endangered life, regardless of cost, at the expense of many nameless faces who will therefore be denied health care.1o This idea makes it difficult for patients, families, and health care providers not to use intensive care for critically ill patients, even if the likely benefit is questionable. When resources were perceived to be unlimited, autonomy was not questioned in the USA. The realisation that scare resources must be allocated fairly to ensure universal access to adequate health care represents a shift towards utilitarian justice and away from autonomy as the driving force in medical decision-making. It may be ethically appropriate to limit a physician’s obligation to an individual according to clearly established and equitable applied constraints set by society. However, it is not clear how this can be put into practice in the USA without changing the doctor-patient relationship, especially in