The effect of smoking on the late patency of arterial reconstructions in the legs

Cigarette smoking intensity informs outcomes after open revascularization for peripheral artery disease

OBJECTIVE

Cigarette smoking is the leading risk factor for peripheral artery disease (PAD). Existing literature often defines smoking history in broad categories of current, former, and never smokers, which may not sufficiently identify patients at the highest risk for poor outcomes. The purpose of this study was to examine the use of more informative categorization of smoking and to determine the association with important revascularization outcomes.

METHODS

We conducted a retrospective review of all patients undergoing open lower extremity revascularization for symptomatic PAD, defined as claudication (Rutherford 3) or critical limb ischemia (Rutherford 4-6), during a 5-year period (2013-2017). Smoking history, demographics, and comorbidities were abstracted from electronic health records from seven hospitals within our health care system. Smoking history was defined by intensity (packs/day), duration (years), pack-year history, and cessation time. Outcomes included major adverse limb events (MALEs), death, limb loss, and amputation-free survival. Cox proportional hazards models were used to calculate hazard ratios and 95% confidence intervals (CIs) for each parameter adjusted for patients' demographics and comorbidities. Cumulative incidence is reported for outcomes at 30, 180, and 365 days of follow-up.

RESULTS

We identified 693 patients undergoing open lower extremity revascularization for PAD (66% critical limb ischemia; 46% diabetes). The 1-year cumulative incidence of MALEs was 29.9% (95% CI, 26.4-33.9), whereas the 1-year incidence of death was 9.8% (95% CI, 7.5-12.7). The broad classification of current and former smokers identified no statistically significant differences in any measured outcomes. Patients who smoked more than one pack/day had 1.48 (95% CI, 1.01-2.16) times increase in risk of MALEs at 1 year compared with patients who smoked one or fewer packs/day. Patients who smoked more than one pack/day also had the highest 1-year amputation incidence (12.7%). Each of the four parameters was associated with increased risk of poor outcomes, although small sample size limited the precision of our estimates.

CONCLUSIONS

We found that smoking intensity is particularly informative of outcomes of patients undergoing open lower extremity revascularization for symptomatic PAD. These findings lay the groundwork for future research on relevant smoking history parameters and benefits of smoking reduction and cessation for clinicians to discuss with patients and to better understand and inform patients of intervention risks and expected outcomes.

Haemoglobin, Smoking and Peripheral Vascular Disease

One hundred and four patients with peripheral vascular disease requiring operation were reviewed retrospectively with respect to age, sex, preoperative haemoglobin, smoking habits and diabetic status. The preoperative haemoglobin levels and smoking status in 63 non-diabetic male patients with peripheral vascular disease were compared with a matched group of individuals treated for inguinal hernia. For all patients there was a significant correlation between smoking habits, preoperative haemoglobin level and the presence of peripheral vascular disease. The mechanisms by which smoking may damage the vascular tree are reviewed.

Hypercoagulable States: A Review

Vascular surgeons are often asked to evaluate patients with recurrent thromboses or thromboses in unusual locations either arterial or venous. There may be obvious inciting factors, but in many of these patients the possibility of a previously undiagnosed hypercoagulable state must be considered. Hypercoagulable states can be acquired (smoking, medication, change in physiologic status as occurs with pregnancy) or congenital. Congenital hypercoagulable disorders are more prevalent in families or patients with a history of thromboembolic events early in life or multiple miscarriages and include conditions such as protein C or S deficiencies, factor V Leiden mutation, and prothrombin gene variant. This article reviews the hypercoagulable states that are encountered in clinical practice as well as guidelines for testing and goals of therapy.

Peripheral arterial disease of the lower extremities

Persons with peripheral arterial disease (PAD) are at increased risk for all-cause mortality, cardiovascular mortality, and mortality from coronary artery disease. Smoking should be stopped and hypertension, dyslipidemia, diabetes mellitus, and hypothyroidism treated. Statins reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in persons with PAD and hypercholesterolemia. The serum low-density lipoprotein cholesterol should be reduced to < 70 mg/dl. Antiplatelet drugs such as aspirin or clopidogrel, angiotensin-converting enzyme inhibitors, and statins should be given to persons with PAD. β-Blockers should be given if coronary artery disease is present. Cilostazol improves exercise time until intermittent claudication. Exercise rehabilitation programs should be used. Revascularization should be performed if indicated.

Risk factors for lower-extremity vein graft failure

Lower-extremity vein graft failure causes significant morbidity, increases health care costs, and negatively impacts patient quality of life. Identification of risk factors is essential for patient selection, risk factor modification, and identifying individuals who would benefit from more stringent surveillance protocols. Risk factors can be considered as either patient-related or technical. Here we discuss the patient-related risk factors for vein graft failure. Nontechnical factors related to the indication for operation include operation after a previously failed graft, or redo bypass, critical limb ischemia, and infection. Risk factors for vein graft failure are distinct from the risk factors for cardiovascular events. Young age and African American and Hispanic race are risk factors for lower-extremity vein graft failure. Hypercoaguable and inflammatory states also increase risk for vein graft failure. Therapy with statins is indicated in patients with peripheral atherosclerosis and may have beneficial effects on vein graft function, although further studies are needed in this area.

Peripheral arterial disease in women

Peripheral arterial disease (PAD) is chronic arterial occlusive disease of the lower extremities caused by atherosclerosis whose prevalence increases with age. Only one-half of women with PAD are symptomatic. Symptomatic and asymptomatic women with PAD are at increased risk for all-cause mortality, cardiovascular mortality, and mortality from coronary artery disease. Modifiable risk factors that predispose women to PAD include active cigarette smoking, passive smoking, diabetes mellitus, hypertension, dyslipidemia, increased plasma homocysteine levels and hypothyroidism. With regard to management, women who smoke should be encouraged to quit and referred to a smoking cessation program. Hypertension, diabetes mellitus, dyslipidemia, and hypothyroidism require treatment. Statins reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in women with PAD and hypercholesterolemia. Anti-platelet drugs such as aspirin or especially clopidogrel, angiotensin-converting enzyme inhibitors and statins should be given to all women with PAD. Beta blockers are recommended if coronary artery disease is present. Exercise rehabilitation programs and cilostazol increase exercise time until intermittent claudication develops. Chelation therapy should be avoided as it is ineffective. Indications for lower extremity percutaneous transluminal angioplasty or bypass surgery in women are (1) incapacitating claudication interfering with work or lifestyle; and (2) limb salvage in women with limb-threatening ischemia as manifested by rest pain, non-healing ulcers, and/or infection or gangrene. Future research includes investigation of mechanisms underlying why women have a higher risk of graft failure and major amputation.

Current concepts in the pathophysiology and management of arteriovenous access-induced hand ischemia

The manifestations of hand ischemia because of an arteriovenous access can range from hand pain, tissue necrosis, and loss of the entire hand. Recent data have emphasized that multiple mechanisms (arterial steal, ie, retrograde flow, arterial stenosis, and arterial calcification) are responsible for inducing hand ischemia. Because any or a combination of the 3 mechanisms can lead to peripheral ischemia, distal hypoperfusion ischemic syndrome is a more appropriate term to denote hand ischemia. A detailed history, physical examination, and differential diagnosis form the initial step in the management of distal hypoperfusion ischemic syndrome. A complete arteriogram to evaluate the circulation of the extremity from the aortic arch to the palmar arch is essential. The choice of treatment modality should be based on this evaluation. In this article, we review the pathophysiology and present current strategies to ameliorate distal hypoperfusion ischemic syndrome.

Reconstructive vascular surgery for intermittent claudication

Over an 8-year period, 140 patients underwent 172 vascular reconstructions (187 reconstructed limbs) to relieve disabling intermittent claudication: bilateral aortoiliac or aortoileofemoral thrombendarterectomy (30 limbs), unilateral iliac or ileofemoral thrombendarterectomy (41 limbs), simultaneous unilateral ileofemoral thrombendarterectomy and femoropopliteal saphenous vein bypass graft (23 limbs), femoropopliteal saphenous vein bypass graft alone (93 limbs). The cumulative 5-year limb patency rates varied between 100 and 85.6% in the four groups. Age and diabetes did not influence patency rates. Only 2 limbs required amputation. These results indicate that reconstruction can be undertaken with a high rate of long-term patency and symptomatic relief In patients with restricting claudication due to aortoiliac, ileofemoral and/or femoropopliteal occlusion.

Estudo comparativo da evolução e sobrevida de pacientes com claudicação intermitente, com ou sem limitação para exercícios, acompanhados em ambulatório específico

CONTEXTO: Os fatores de risco para doença aterosclerótica, que influenciam na evolução natural dessa doença, estão bem estabelecidos, assim como o benefício do programa de exercícios para pacientes claudicantes. Entretanto, faltam informações sobre a relação entres limitações clínicas e fatores de risco, com desempenho do programa de caminhadas e suas implicações na evolução e mortalidade destes pacientes. OBJETIVO: Comparar, ao longo do tempo, a distância de claudicação e sobrevida de pacientes claudicantes em ambulatório específico, com ou sem limitação para exercícios. MÉTODOS: Foi feito um estudo tipo coorte retrospectivo de 185 pacientes e 469 retornos correspondentes, no período de 1999 a 2005, avaliando-se dados demográficos, distância média de claudicação (CI) e óbito. Os dados foram analisados nos programas Epi Info, versão 3.2, e SAS, versão 8.2. RESULTADOS: A idade média foi de 60,9±11,1 anos, sendo 61,1% do sexo masculino e 38,9% do sexo feminino. Oitenta e sete por cento eram brancos, e 13%, não-brancos. Os fatores de risco associados foram: hipertensão (69,7%), tabagismo (44,3%), dislipidemia (32,4%) e diabetes (28,6%). Nos claudicantes para menos de 500 m, a CI inicial em esteira foi de 154,0±107,6 m, e a CI final, de 199,8±120,5 m. Cerca de 45% dos pacientes tinham alguma limitação clínica para realizar o programa de exercícios preconizado, como: angina (26,0%), acidente vascular cerebral (4,3%), artropatia (3,8%), amputação menor ou maior com prótese (2,1%) ou doença pulmonar obstrutiva crônica (1,6%). Cerca de 11,4% dos pacientes tinham infarto do miocárdio prévio, e 5,4% deles usavam cardiotônico. O tempo de seguimento médio foi de 16,0±14,4 meses. A distância média de CI referida pelos pacientes aumentou 100% (de 418,47 m para 817,74 m) ao longo de 2 anos, nos grupos não-limitante (p < 0,001) e não-tabagista (p < 0,001). A sobrevida dos claudicantes foi significativamente menor no grupo com limitação. A análise de regressão logística mostrou que a limitação para realização de exercícios, isoladamente, influenciou significativamente na mortalidade (p < 0,001). CONCLUSÃO: A realização correta e regular dos exercícios e o abandono do fumo melhoram a distância de claudicação, além de reduzir a mortalidade nesses casos, seja por meio de efeitos positivos próprios do exercício, seja por meio de controle dos fatores de risco e de seus efeitos adversos.

[Preoperative factors influencing the early results of infrainguinal limb salvage procedures]

INTRODUCTION

The early results of 59 patients treated surgically for critical limb ischemia at the Institute of Cardiovascular Diseases were analyzed. Research was performed in a prospective manner, as an acute study, lasting for three months.

OBJECTIVE

Our focus was on primary and secondary patency rate, and graft efficacy (quality accomplished by graft patency, improvement of clinical status of the leg, and quality of life).

METHOD

The influence of each variable on the outcome was analyzed (descriptive: sex, comorbidity, risk factors, clinical stage of disease, angiographic verification of pedal arch, previous vascular procedures; and numerical: gender, preoperative Doppler index, angiographic score by Bollinger), as well as their predictive value. Inferential statistics was used for establishing the significance of influence, and univariate regression analysis for predictive values.

RESULTS

No influence of variables on the outcome was evident in the first three months, and their predictive value was not important considering the graft patency rates and efficacy (except for preoperative clinical status affecting the graft efficacy, presence of pedal arch, affecting both primary and secondary patency rates and graft efficacy, and finally Doppler index affecting the secondary patency rates).

CONCLUSION

When the surgeon needs to give an early prediction of graft destiny, he can rely on preoperative clinical status, earlier vascular operative procedures, presence of pedal arch, and values of Doppler index (in case of reintervention).

The role of established and emerging risk factors in peripheral vascular graft occlusion

Several studies have evaluated the association between established as well as emerging vascular risk factors with peripheral graft occlusion. There is evidence for a link between the risk for graft occlusion and total serum cholesterol, low-density lipoprotein cholesterol and triglyceride levels. The overall effect of smoking shows a 2.35-fold increase in risk of graft failure. Studies involving diabetic patients undergoing peripheral bypass may have failed to detect higher occlusion rates, possibly due to increased morbidity and mortality as well as higher amputation rates even if the graft is patent. Both antiplatelet agents and anticoagulation seem to be effective in the prevention of graft occlusion. Unconvincing data have been published with regards to the effect of hypertension on graft patency. Emerging factors such as fibrinogen, lipoprotein (a), C-reactive protein and homocysteine levels should also be considered when assessing the risk of graft occlusion. More research is needed to prevent graft occlusion due to the obvious clinical relevance, quality of life and cost issues.

Peripheral arterial disease in the elderly

Smoking should be stopped and hypertension, diabetes mellitus, dyslipidemia, and hypothyroidism treated in elderly patients with peripheral arterial disease (PAD) of the lower extremities. Statins reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in patients with PAD and hypercholesterolemia. Antiplatelet drugs such as aspirin or clopidogrel, especially clopidogrel, angiotensin-converting enzyme inhibitors, and statins should be given to all elderly patients with PAD without contraindications to these drugs. Beta blockers should be given if coronary artery disease is present. Exercise rehabilitation programs and cilostazol increase exercise time until intermittent claudication develops. Chelation therapy should be avoided. Indications for lower extremity percutaneous transluminal angioplasty or bypass surgery are (1) incapacitating claudication in patients interfering with work or lifestyle; (2) limb salvage in patients with limb-threatening ischemia as manifested by rest pain, nonhealing ulcers, and/or infection or gangrene; and (3) vasculogenic impotence.

Arteriovenous access and hand pain: the distal hypoperfusion ischemic syndrome

An ischemic hand in a hemodialysis patient is a serious condition. It causes significant pain and discomfort but also can lead to tissue necrosis and the eventual loss of digits and even the entire hand. Although stealing of blood away from the high-resistance forearm arteries into the low-resistance arteriovenous access generally is assumed to be the cause, a great majority of both wrist and elbow accesses demonstrate retrograde flow without any evidence of hand pain or ischemia. Consequently, demonstration of retrograde flow alone does not predict or indicate the existence of distal ischemia. In this context, the term "arterial steal syndrome" is a misnomer to indicate the presence of peripheral ischemia. Recent studies have shown that, in many cases, arterial stenotic lesions cause distal hypoperfusion and result in hand ischemia. In other cases, distal arteriopathy as a result of generalized vascular calcification and diabetes is the culprit. Because any or a combination of the three mechanisms (retrograde flow, stenotic lesions, and distal arteriopathy) can lead to peripheral ischemia, distal hypoperfusion ischemic syndrome is a more appropriate term to denote hand ischemia. Treatment should start with a detailed history and physical examination to help rule out other (nonischemic) causes of hand pain. A complete arteriogram to evaluate the circulation of the extremity from the aortic arch to the palmar arch is essential. The choice of treatment modality and procedure to apply should be based on this evaluation. This report reviews the pathophysiology and presents current strategies to ameliorate distal hypoperfusion ischemic syndrome.

Drug treatment of peripheral arterial disease in the elderly

Peripheral arterial disease (PAD) may be asymptomatic, may be associated with intermittent claudication or may be associated with critical limb ischaemia. Coronary artery disease (CAD) and other atherosclerotic vascular disorders may coexist with PAD. Persons with PAD are at increased risk for all-cause mortality, cardiovascular mortality and mortality from CAD. Smoking should be stopped and hypertension, diabetes mellitus, dyslipidaemia and hypothyroidism treated. HMG-CoA reductase inhibitors (statins) reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in persons with PAD and hypercholesterolaemia. Antiplatelet drugs such as aspirin or clopidogrel (especially the latter), ACE inhibitors and statins should be given to all persons with PAD. beta-Adrenoceptor antagonists should be given if CAD is present. The phosphodiesterase type 3 inhibitor cilostazol improves exercise time until intermittent claudication. Chelation therapy should be avoided. Correct implementation of medical therapy significantly reduces the excess mortality associated with PAD. In addition, medical therapy may result in significant improvements in walking ability that may obviate the need for lower extremity angioplasty with stenting and bypass surgery.

Arterial Steal Syndrome: A Modest Proposal for an Old Paradigm

BACKGROUND

Access ligation has been considered to be the treatment for patients presenting with arterial steal syndrome by many nephrologists. We report results of a prospective study using comprehensive arteriography coupled with percutaneous transluminal balloon angioplasty (PTA) or surgical intervention to evaluate and manage steal syndrome.

METHODS

Twelve consecutive patients referred for symptoms of steal syndrome were examined. Comprehensive arteriography of the extremity to diagnose arterial stenoses and delineate anatomy was performed by advancing a diagnostic catheter into the subclavian artery. Findings of arteriography and degrees of stenosis before and after PTA also were documented. Resolution of symptoms after PTA and surgical interventions, as well as complications, were recorded.

RESULTS

Angiography showed arterial stenotic lesions in 10 of 12 patients (83%). The degree of stenosis was 66% +/- 14% (SD). Eight patients (80%) with stenotic lesions underwent PTA successfully. The degree of stenosis after PTA was 13% +/- 10%. The remaining 2 patients were not considered candidates for PTA and were referred to surgery with arteriography images. One patient underwent ligation and the other patient required an axillary loop fistula using the same outflow vein. The 2 patients without stenoses showed excessive steal through the anastomosis and underwent lengthening procedures by insertion of a vein segment. All 12 patients are symptom free with a mean follow-up of 8.3 +/- 4 months, and 11 of 12 patients (92%) are dialyzing using the same access. There were no procedure-related complications.

CONCLUSION

We suggest that complete imaging of the arterial circulation of the extremity be considered in patients presenting with symptoms of steal syndrome to properly assess the arterial anatomy and develop a treatment strategy.

Management of peripheral arterial disease in chronic kidney disease

PAD has been overlooked in many epidemiologic studies evaluating cardiovascular risk associated with renal disease. Conversely, CKD has not been evaluated as a potential risk factor in epidemiologic studies of PAD. PAD, however,seems to be more prevalent among patients with even moderate CKD than in the general population and is most common among chronic dialysis patients, one third or more of whom have a low ABI. Patients with CKD also seem to be at increased risk for developing claudication and for requiring surgical intervention for lower extremity PAD. Furthermore, even moderate CKD seems to be a risk factor for postoperative death and complications after both lower extremity amputation and revascularization procedures. Conversely, even asymptomatic PAD seems to be a risk factor for death among dialysis patients. In the general population, statins, antiplatelet agents (particularly clopidogrel), antihypertensive agents, and ACE inhibitors all have a proven benefit in reducing cardiovascular events in patients with PAD and in some instances may also reduce PAD events. Available evidence suggests that patients with CKD also experience cardio-vascular risk reduction with statin and ACE-inhibitor therapy, but these therapies have not been shown to reduce PAD events specifically in patients with CKD. Further studies are needed to identify interventions that can specifically reduce the incidence of PAD complications in patientswith CKD. Although it is clear that mortality and complication rates after both lower extremity amputation and revascularization are increased in patients with even moderate CKD, currently available observational studies do not provide clear guidance for surgical decision making in CKD patients with limb-threatening ischemia. Further studies are needed to evaluate the risksand benefits of amputation over revascularizationamong patients with CKD and to investigatereasons for the high mortality associated with these procedures in this patient group. Further studies are also needed to measure the impact of CKD on care processes for PAD with the goal of identifying target areas for improvement.

Smoking and the patency of lower extremity bypass grafts: A meta-analysis

OBJECTIVE

Smoking is the major risk factor associated with the development and progression of peripheral arterial disease (PAD). To establish the best estimate of the effect of smoking, smoking cessation, and the dose-response relationship on the patency of lower extremity bypass grafts, we performed a systematic review.

METHODS

A search of medical articles and reviews relating to the influence of smoking on the patency of arterial reconstructive grafts in patients with PAD was made. Studies considered for inclusion were those that evaluated the influence of smoking on the primary, secondary, or cumulative patency rates of arterial reconstructive surgery in the lower extremities in patients with PAD. Primary data were used to calculate summary estimates with standard meta-analysis techniques.

RESULTS

The 29 eligible studies included 4 randomized clinical trials, 12 prospective studies, and 13 retrospective studies. The effect of smoking on graft patency in the randomized clinical trials and other prospective studies had a 3.09-fold (2.34 to 4.08; P < .00001) increase in graft failure. A comparison of patency rates among all studies that used autogenous or polyester grafts showed no difference. A clear dose-response relationship was present, with a decreased patency in heavy smokers compared with moderate smokers. Smoking cessation restores patency rates toward the never smokers group.

CONCLUSION

Continued smoking after lower limb bypass surgery results in a threefold increased risk of graft failure. Smoking cessation, even if instigated after the operation, restored graft patency towards the patency of never smokers. These results indicate that adequate smoking cessation strategies in patients eligible for lower limb bypass surgery are of utmost importance.

Management of Peripheral Arterial Disease

Peripheral arterial disease (PAD) may be asymptomatic, may be associated with intermittent claudication, or may be associated with critical limb ischemia. Coronary artery disease (CAD) and other atherosclerotic vascular disorders may coexist with PAD. Persons with PAD are at increased risk for all-cause mortality, cardiovascular mortality, and mortality from CAD. Modifiable risk factors such as cessation of cigarette smoking and control of dyslipidemia, hypertension, and diabetes should be treated. Statins reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in persons with PAD and hypercholesterolemia. Antiplatelet drugs such as aspirin or clopidogrel, especially clopidogrel, and angiotensin-converting enzyme inhibitors should be given to all persons with PAD. beta-Blockers should be given if CAD is present. Exercise rehabilitation programs and cilostazol improve exercise time until intermittent claudication. Indications for lower-extremity angioplasty, preferably with stenting, or bypass surgery are 1) incapacitating claudication in persons interfering with work or lifestyle; 2) limb salvage in persons with limb-threatening ischemia as manifested by rest pain, nonhealing ulcers, and/or infection or gangrene; and 3) vasculogenic impotence. However, amputation should be performed if tissue loss has progressed beyond the point of salvage, if surgery is too risky, if life expectancy is very low, or if functional limitations diminish the benefit of limb salvage.

Management of Peripheral Arterial Disease of the Lower Extremities in Elderly Patients

The prevalence of peripheral arterial disease (PAD) increases with age. PAD in elderly persons may be asymptomatic, may be associated with intermittent claudication, or may be associated with critical limb ischemia. Other atherosclerotic vascular disorders, especially coronary artery disease (CAD), may coexist with PAD. Elderly persons with PAD are at increased risk for all-cause mortality, cardiovascular mortality, and mortality from CAD. Modifiable risk factors should be treated in persons with PAD such as cessation of cigarette smoking and control of hypertension, dyslipidemia, and diabetes. Statins have been shown to reduce the incidence of intermittent claudication and to improve treadmill exercise duration until the onset of intermittent claudication in persons with PAD and hypercholesterolemia. Antiplatelet drugs such as aspirin or clopidogrel, especially clopidogrel, should be administered to all persons with PAD. Persons with PAD should be treated with angiotensin-converting enzyme inhibitors and also with beta blockers if CAD is present. Cilostazol should be given to persons with intermittent claudication to improve exercise capacity unless heart failure is present. Exercise rehabilitation programs improve exercise time until claudication. Indications for lower extremity angioplasty, preferably with stenting, or bypass surgery are 1) incapacitating claudication in persons interfering with work or lifestyle; 2) limb salvage in persons with limb-threatening ischemia as manifested by rest pain, nonhealing ulcers, and/or infection or gangrene; and 3) vasculogenic impotence. However, amputation should be performed if tissue loss has progressed beyond the point of salvage, if surgery is too risky, if life expectancy is very low, or if functional limitations obviate the benefit of limb salvage.

Epidemiology of smoking-induced cardiovascular disease

Cigarette smoking is a major cause of coronary heart disease, stroke, aortic aneurysm, and peripheral vascular disease. The risk is manifest both as an increased risk for thrombosis of narrowed vessels and as an increased degree of atherosclerosis in those vessels. The cardiovascular risks owing to cigarette smoking increase with the amount smoked and with the duration of smoking. Risks are not reduced by smoking cigarettes with lower machine-measured yields of tar and nicotine, but those who have only smoked pipes or cigars seem to have a lower risk for cardiovascular diseases. Cessation of cigarette smoking reduces disease risks, although risks may remain elevated for a decade or more after cessation.

How do vascular surgeons perceive atherosclerotic risk factor management?

The specific objectives of this report were to determine (1) the usual practice of vascular surgeons with respect to risk factor inquiry and intervention, (2) which risk factors are endorsed by vascular surgeons as being very important in the management of patients with PAD, and, finally, (3) which risk factors vascular surgeons are confident in managing.

Antiplatelet therapy and other interventions after revascularisation procedures in patients with peripheral arterial disease: a meta-analysis

OBJECTIVES

To evaluate the efficacy of conservative adjuvant therapy after revascularisation procedures in patients with peripheral arterial disease.

DESIGN

meta-analysis.

MATERIALS

English-language studies published from 1976 to 1997.

METHODS

Reports on conservative therapies in patients with peripheral arterial disease after percutaneous transluminal angioplasty, endarterectomy, thromboendarterectomy or bypass grafting were eligible. Uncontrolled or retrospective studies, double reports or trials without clinical outcomes were excluded. Included studies were graded as level 1 (randomised and double- or assessor-blind), level 2 (open randomised), or level 3 (non-randomised comparative). (Loss of) patency, amputation, vascular events and mortality were the outcomes considered. When feasible, end-of-treatment results, either continuous or binary, were combined with appropriate statistical methods.

RESULTS

Thirty-two studies were included. Compared to non-active control, aspirin with dipyridamole improved (loss of) patency (odds ratio (OR) 0.69, 95% confidence interval (CI), 0.53 to 0.90) and mortality (OR 0.80, 95% CI, 0.57 to 1.14); ticlopidine improved (loss of) patency (OR 0.53, 95% CI, 0.33 to 0.85) and amputation (OR 0.29, 95% CI, 0.08 to 1.01). Data on the effectiveness of vitamin-K inhibitors were not conclusive.

CONCLUSIONS

Patients with peripheral arterial disease improve their outcome by receiving aspirin with dipyridamole or ticlopidine after a revascularisation procedure.

The caput medusae of hypercoagulability

Thrombosis may be the most common cause of death in the United States. Virchow postulated, approximately 150 years ago, that intravascular thrombosis was caused by changes of the vessel wall, by reduction in blood flow, and by alteration of the chemical composition of the blood. The hypercoagulability component of the Virchow triad has, until recently, been poorly defined. During the past 40 years, a number of acquired and congenital hypercoagulable disorders have been described so that currently the cause for thrombotic events can be determined in many patients. The hypercoagulable-related thromboses are usually venous but may, less often, be arterial, and the thromboses often are the cause of significant morbidity and mortality. The vascular surgeon often participates in the management of hypercoagulable disorders. This review of hypercoagulable disorders is presented with the hope that the early recognition of these disorders will lead to the appropriate diagnosis and proper management of hypercoagulable-related thromboses.

[Diagnostic and therapeutic stragegies in peripheral obliterative arteriopathy: non-drug treatment]

The therapeutic management of patients with peripheral arterial disease relies initially on the assessment of the severity of arterial insufficiency. At this stage, measurement of ankle systolic pressure plays a particularly important role, and is an essential part of the clinical examination. When the severity of ischaemia jeopardises the survival of a limb, the limitations associated with medical treatment clearly justify all steps being taken to enable the patient to benefit from revascularisation. In this often fragile host environment, endovascular techniques play an important part. As first-line procedures, they have a place within a multidisciplinary management approach, particularly since further surgical procedures, such as distal bypass, often prove necessary. For patients at the intermittent claudication stage, treatment indications become more complex. They include the functional repercussions of peripheral arterial occlusive disease and the cardiovascular prognosis for the patient, which is determined by assessing the extent of the arterial disease. Ultrasonography provides a topographical evaluation of the lesions and their haemodynamic repercussions. This investigation is crucial for screening patients who present with a lesion that may be appropriate for endovascular surgery. Ultrasonography is often programmed at the same time as arteriography. For patients with intermittent claudication, surgical revascularisation is considered only after a minimum 3-month period of medical treatment, for those who have significant functional impairment. In some instances, ultrasonographic evaluation, or even arteriography, may reveal lesions associated with a real risk of deterioration, such as arterial or popliteal aneurysm, and this constitutes the basis of the indication. The development of endovascular techniques has broadened the indications for surgical revascularisation to include patients with intermittent claudication. As a result, there has been a radical change with regard to the management of these patients, limiting the number for whom medical treatment is the only feasible solution.

[Quality of life and peripheral obliterative arteriopathy. Perspective for the future]

Atherosclerosis is the primary cause of peripheral arterial disease. Because atherosclerosis is a generalised disease, it is possible that patients with peripheral arterial disease may have other arterial disorders. Such patients have a reasonable chance of continuing to walk, although their general prognosis is less favourable because of high cardiovascular morbidity and mortality. Nevertheless, the following approaches can be used to improve the management of patients with peripheral arterial disease: diagnosis of peripheral arterial disease in its early stages by systematic measurement of the ankle/brachial index; improvement in screening for lesions in other arteries by analysing the clinical symptomatology and performing simple complementary examinations; improvement in the management of atherosclerosis risk factors, particularly cigarette smoking, as well as in the treatment of diabetes, arterial hypertension and hypercholesterolaemia; enhancement of antithrombotic agents by the development of new, more effective antiplatelet drugs. Finally, quality of life should be considered an essential factor governing treatment choice. A self-administered questionnaire concerning intermittent claudication has been used to assess the quality of life of patients with peripheral arterial disease undergoing treatment with ifenprodil tartrate. This study showed that the evaluation of intermittent claudication should not be limited to walking distance alone, but that a more general criterion, better adapted to atherosclerotic disease, should be considered: measurement of quality of life.

The role of tobacco cessation, antiplatelet and lipid-lowering therapies in the treatment of peripheral arterial disease

Despite the widely held belief that there are no effective medical therapies for peripheral arterial disease (PAD), current data suggest that medical therapies can effectively modify the natural history of atherosclerotic lower extremity arterial occlusive disease. The ideal medical therapy would improve claudication, forestall the onset of limb-threatening events, decrease rates of invasive interventional therapies and improve long-term patient survival. These ideal outcomes might be achieved through the use of smoking cessation interventions, including behavioral and pharmacological therapy, and the administration of antiplatelet and lipid-lowering medications in patients with PAD.

Results of aortic bifurcation grafts for aortoiliac occlusive disease: a meta-analysis

PURPOSE

To summarize mortality, morbidity, and long-term patency data of bifurcated aortoiliac or aortofemoral bypass graft procedures in aortoiliac occlusive disease.

METHODS

A Medline search was performed of the medical literature published between 1970 and 1996. Studies were included if (1) they reported patency rates based on life tables and the number at risk was provided at yearly intervals; and (2) patient and study characteristics were reported in sufficient detail. Mortality and morbidity risks were pooled using a fixed-effects model. The patency data were combined using a technique that enables adjustment for differences across studies in patient characteristics or reporting methods. In the current analysis, we corrected for the symptomatic status of the patients at the time of surgery (claudication vs ischemia) and the unit of observation used in reporting the patency (limb vs patient).

RESULTS

We identified 23 studies that met the inclusion criteria. The aggregated operative mortality risk in the older studies (started before 1975) was 4.6%, as compared with 3.3% in the more recent studies (p = 0.01). The aggregated systemic morbidity risk was 13.1% in the older studies and 8.3% in the more recent studies (p < 0.001). Limb-based patency rates for patients with claudication were 91.0% and 86.8% at 5 and 10 years, respectively, as compared with 87.5% and 81.8% for patients with ischemia. Patency rates reported in the older studies were markedly similar to those of more recent studies (p = 0.58).

CONCLUSIONS

Our study suggests that mortality and systemic morbidity rates of aortic bifurcation graft procedures have dropped since 1975, whereas patency rates seem to be fairly constant over the years.

The benefits of stopping smoking and the role of nicotine replacement therapy in older patients

Considerable benefits accrue from stopping smoking in older patients. Reversal of the short term cardiovascular adverse effects of smoking is rapid. Long term risk reduction appears to occur as a result of decreased life-time exposure to tobacco smoke. The pharmacology of nicotine has not been studied in older patients but is unlikely to change in clinically important ways with advancing age. Nicotine replacement doubles long term success rates, compared with placebo, among younger smokers of > or = cigarettes per day. There is no reason to believe its efficacy should be less among older smokers. Transdermal nicotine is the replacement therapy of choice in older patients because of once-daily administration and good tolerability. Approximately half of the users of transdermal nicotine smoke concurrently with treatment. It is unlikely that concurrent smoking or high doses of nicotine replacement therapy will adversely effect healthy patients. While it is generally believed that patients with unstable coronary heart disease may be at risk from concurrent smoking during nicotine replacement therapy, it is unclear whether this risk is greater than the risk of smoking alone. Nicotine replacement therapy is a logical approach for motivated, older smokers who are unable to stop smoking by simpler means. Results can be augmented by including other interventions, such as counselling and follow-up support.

Smoking and plasma fibrinogen, lipoprotein (a) and serotonin are markers for postoperative infrainguinal graft stenosis

OBJECTIVES

A number of systemic variables are associated with infrainguinal graft failure and also with experimental smooth muscle hyperplasia. Stenosis is the most common cause of infrainguinal graft thrombosis but it is not known if systemic variables are associated with stenosis.

DESIGN, MATERIALS, AND METHODS

In this study, clinical and serological factors were measured and correlated with stenosis development in 81 infrainguinal bypass grafts (52 vein, 29 PTFE; 28 with stenosis) in prospective (n=46) and retrospective (n=35) groups. Pre-existing stenosis was excluded by perioperative graft assessment.

RESULTS

There was a significantly greater proportion of smokers in the patients who developed stenosis (11/18; 61%) compared with those who did not (6/28; 21%, p=0.006; chi 2). Patients who developed stenosis also had significantly (Mann Whitney U-tests), higher circulating levels of [median (interquartile range)] fibrinogen (412.5 (356-484.5) vs. 339 (300-397.7) mg/100ml, p=0.003), Lipoprotein (a) (0.20 (0.05-0.45) vs. 0.085 (0.05-0.23) g/l, p=0.03) and 5-hydroxytryptamine (14.1 (6.6-45) vs. 4.41 (3-8.39) nmol/l, p=0.005), than those without stenosis. By logistic regression, these associations were independent of graft material and whether grafts were studied prospectively or retrospectively.

CONCLUSIONS

Smoking and plasma fibrinogen, Lp(a) and 5-hydroxytryptamine are markers for postoperative infrainguinal graft stenosis.

Cigarette smoking increases the development of initial hyperplasia after vascular injury

PURPOSE

Our purpose was to determine whether exposure to cigarette smoke increases the development of intimal hyperplasia (IH) after vascular injury.

METHODS

Sixteen adult male Sprague-Dawley rats underwent standardized balloon catheter injury of the left common carotid artery. For 4 weeks before and 4 weeks after injury, animals in the experimental group (n=8) were exposed to cigarette smoke with an automated vacuum pump device. Animals in the control group (n=8) were restrained in the smoking device for an identical amount of time and underwent arterial injury at 4 vivo, prepared as histologic cross sections, and stained for elastin. IH was measured by planimetry and is reported both as the absolute area of IH and as the ratio (IH/IEL) of the absolute area of IH to the normalized area enclosed by the internal elastic lamina (expressed as a percent).

RESULTS

The absolute area of IH was 2.09 +/- 0.34 for the experimental group compared with 0.94 +/- 0.25 for the control group; mean IH/IEL was 43% +/- 7.1% for the experimental group versus 17.7% +/- 4.7% for the control group (p < 0.05, two tailed unpaired t test.

CONCLUSIONS

Inhalation of cigarette smoke increases the development of intimal hyperplasia in a rat model of a balloon catheter arterial injury.

The effect of cigarette smoking on the survival of free vascularized and pedicled epigastric flaps in the rat

Microsurgeons suspect that cigarette smoking reduces the survival of free vascularized flaps and replantations, but this has never been proven. This experimental study investigates the effect of smoking on free-flap survival. A fasciocutaneous epigastric flap was used in 30 rats as a free flap and in 30 rats as a pedicled flap. Of each group, 10 rats were smoked 6 weeks before and 2 weeks after surgery, 10 rats were smoked only 6 weeks before surgery, and 10 rats underwent the sham smoking procedure. Also, a distally based dorsal skin flap was cut in all rats, representing a random vascularized flap. Vitality and size of both flaps and patency of the vascular anastomoses were assessed 14 days after surgery. The epigastric flaps were monitored by laser Doppler flowmetry and thermometry during the experiment. Survival of the free vascularized epigastric flaps was significantly lower in smoking rats. All pedicled flaps except one survived. The epigastric flaps only necrosed or survived completely, exactly correlating to the patency of the vascular anastomoses. The mean surviving area of the dorsal flaps was best for nonsmoking rats, worse for only preoperatively smoking rats, and worst for preoperatively and postoperatively smoking rats. The differences were statistically significant. Postoperative laser Doppler flow differed significantly between surviving and dying flaps, affirming the value of laser Doppler flow monitoring in microvascular surgery. In conclusion, this study proves that smoking of cigarettes is detrimental to the survival of free vascularized flaps.

Medical management of peripheral arterial disease

Patients with atherosclerotic peripheral arterial disease (PAD) of the lower extremities have an inadequate blood flow to exercising muscle. This results in a walking impairment due to intermittent claudication (exercise-induced cramping in the muscles of the lower extremities). Persons with PAD are at increased risk of cardiovascular events, with an excess mortality from strokes and myocardial infarction. The medical treatment of patients with PAD is directed at intensive risk factor modification to decrease cardiovascular morbidity and mortality. A second treatment goal is to improve exercise performance and functional capacity. To this end, a limited number of drugs have been developed to improve claudication symptoms. In addition, the nonpharmacologic treatment of claudication includes exercise rehabilitation. Previous studies have shown that an exercise rehabilitation program results in significant increases in treadmill peak walking time, peak oxygen consumption, and pain-free walking time. Patients also reported improved walking ability and functional status in the community setting. Therefore, optimal treatment of this patient population includes cardiovascular risk factor modification, selective use of claudication drugs, and exercise rehabilitation.

Expanded polytetrafluoroethylene arterial prostheses in humans: histopathological study of 298 surgically excised grafts

The expanded polytetrafluoroethylene vascular prosthesis is considered to be the best synthetic alternative for peripheral arterial reconstruction. Most studies on the healing characteristics of expanded polytetrafluoroethylene prostheses have been carried out on animals, and very few data are available on prosthesis implanted in humans long term. We implanted 298 expanded polytetrafluoroethylene grafts as arterial substitutes in humans. The mean duration of implantation was 523 d and the grafts were implanted mainly for infrainguinal or axillofemoral bypass. The cellular and collagen infiltration of the microporous expanded polytetrafluoroethylene structure was generally poor. Infiltration occurred mainly in the external region of the prosthetic wall and increased with the duration of implantation. The external reinforcement was not a major factor in limiting tissue infiltration. The luminal surfaces were covered with a thin, irregular layer of organized fibrin, interspersed with exposed expanded polytetrafluoroethylene areas. Mineral deposits were observed in five cases. Despite poor healing, the clinical performance of expanded polytetrafluoroethylene vascular prostheses is relatively good. Since the chief advantage of this material is good mechanical stability in vivo, any modifications of the graft to improve healing characteristics or thrombogenic properties should not be made at the expense of stability in vivo.

Risk factors for atherosclerotic aortoiliac occlusive disease

Notwithstanding the difficulties in analysis because of the small number of studies available, patients with aortoiliac atherosclerosis, irrespective of their sex, have a particular "risk profile" that includes tobacco use, young age, diabetes (rare), frequent hypercholesterolemia, and limited atheroma. It must be remembered, however, that most studies have not dealt with the specific risk factors of lower limb arterial disease and the location of disease in the aortoiliac vessels. It is possible that the classical analysis of the vascular risk factors has overlooked one or more major factors such as hyperhomocysteinemia. This underscores the necessity to conduct further prospective studies specifically focused on the various aspects of lower limb and aortoiliac arterial disease in particular.

Multivariate Cox regression analysis of covariates for patency rates after femorodistal vein bypass grafting

Multivariate Cox regression analysis of patency rates for 750 consecutive femorodistal autogenous vein graftings for chronic lower limb ischemia showed that significant independent prognostic covariates were the type of graft (long saphenous or arm vein), presence of diabetes, and absence of a past history of myocardial ischemia. Analysis assumes that patients withdrawn with patent grafts due to death or loss to follow-up would have followed the same course as those who remain, and the degree to which this could distort results was studied. Patients who died with patent grafts were more likely to have had past myocardial ischemia and critical lower limb ischemia. Cox regression analysis for 600 operations after excluding patients who died with patent grafts then showed that significant independent covariates were the type of graft (long saphenous or arm vein) and indication (claudication or critical ischemia); then age, sex, hypertension, diabetes, myocardial ischemia, date of operation, surgeon, site of distal anastomosis, or first compared to repeat operations had no significant influence. Cox regression analysis helps determine which covariates influence graft patency rates, but results are affected by censored data, particularly from patients who die with patent grafts.

Smoking and cardiovascular disease

Cigarette smoking is the most preventable cause of cardiovascular morbidity and mortality. Smoking has been associated with a two-to fourfold increased risk of coronary heart disease, a greater than 70% excess rate of death from coronary heart disease, and an elevated risk of sudden death. These risks are compounded in the presence of hypertension, hypercholesterolemia, glucose intolerance, and diabetes, all of which exhibit a synergistic effect with smoking. The relationship between smoking and the risk of peripheral vascular disease has also been well documented. Smokers account for approximately 70% of patients with atherosclerosis obliterans and virtually all those with thromboangiitis obliterans. An association between smoking and cerebrovascular disease remains a matter of debate, although a higher risk of stoke and stroke-related mortality has been observed in smokers than in nonsmokers. Smoking has also been implicated in the development of cor pulmonale, but a direct association with congestive heart failure has not been established. Nicotine and carbon monoxide appear to play major roles in the cardiovascular effects of smoking. Both components adversely alter the myocardial oxygen supply/demand ratio and have been shown to produce endothelial injury, leading to the development of atherosclerotic plaque. Adverse effects on the lipid profile have been noted as well, but the relationship between these changes and the risk of cardiovascular disease remains to be confirmed. Notably, smoking cessation results in a dramatic reduction in the risk of mortality from both coronary heart disease and stroke. In light of the fact that the incidence of smoking has declined primarily among educated sectors of the U.S. population, future efforts must focus on providing effective education, including smoking cessation techniques, to the less-educated groups.

Detection of reversible platelet aggregates in the blood of smokers and ex-smokers with peripheral vascular disease

OBJECTIVE

To demonstrate that smoking increases platelet aggregation in vivo, that smoking cessation reverses platelet aggregation and that this explains, in part, why smoking perpetuates the development of peripheral vascular disease.

DESIGN

Prospective case-control study involving three groups of patients: smokers with peripheral vascular disease, ex-smokers with peripheral vascular disease and smokers with peripheral vascular disease who quit smoking during the study.

SETTING/PARTICIPANTS

Fourteen smokers and seven ex-smokers, new patients with confirmed peripheral vascular disease, attending the vascular clinic at Fremantle Hospital between February and November, 1988.

INTERVENTIONS

Blood samples taken weekly from all subjects for five weeks. Week 1 was taken as the baseline before smoking cessation in the six smokers who were assigned to stop smoking during the study.

MAIN OUTCOME CRITERIA

Platelet aggregate ratio, an indicator of in-vivo platelet aggregability where an increase in platelet aggregate ratio suggests a decrease in platelet function.

RESULTS

Only three of six smokers stopped smoking for the duration of the study. Median platelet aggregate ratios were: smokers = 0.85 (range, 0.79-0.92) v. non-smokers = 0.93 (range, 0.91-1.00). The difference was statistically significant P less than 0.0002. The difference in platelet aggregate ratios between smokers and quitters was not statistically significant.

CONCLUSIONS

This study demonstrated an increase in platelet aggregability in smokers compared to ex-smokers but there was no clear evidence that platelet function was fully reversed after only four weeks cessation of smoking. The data suggested that platelet function of the ex-smokers had fully reversed to normal over a longer period. This could explain the decreased incidence of complications of peripheral vascular disease in ex-smokers. The small number of patients able to quit smoking impeded this study.

The peripheral vascular consequences of smoking

Cigarette smoking is associated with an increased risk and extent of advanced atherosclerotic vascular disease in peripheral as well as coronary arteries. The likelihood of claudication, amputation, stroke, abdominal aortic aneurysm, and failure of vascular reconstruction is higher in smokers than nonsmokers. Smoking exerts its deleterious effects through many interactive mechanisms. Nicotine and carbon monoxide produce acute cardiovascular consequences, including altered myocardial performance, tachycardia, hypertension, and vasoconstriction. Smoking injures blood vessel walls by damaging endothelial cells, thus increasing permeability to lipids and other blood components. Among metabolic and biochemical changes induced by smoking are elevated plasma, free fatty acids, elevated vasopressin, and a thrombogenic balance of prostacyclin and thromboxane A2. Chronic smoking is associated with a tendency for increased serum cholesterol, reduced high density lipoprotein, and other lipid effects that contribute to atherosclerosis. In addition to rheologic and hematologic changes from increased erythrocytes, leukocytes, and fibrinogen, smokers have alterations in platelet aggregation and survival that produce thrombosis. Considering the ubiquitous repercussions of this menace, vascular surgeons should play an active role in motivating their patients to quit smoking.

Graft occlusion following aortofemoral Dacron bypass

We report on a series of 930 patients who received an aortobifemoral Dacron graft between 1963 and 1988. The operative mortality was 5.6% and the mean follow-up reached 5.45 years (range one month to 23.6 years). Late occlusion was noted in 125 patients and the primary patency rate decreased to 74% and 69%, respectively at 10 and 15 years. Long-term patency was primarily (p less than 0.05) dependent on (1) the date of operation, (2) postoperative smoking habits, (3) distal occlusive disease, and (4) age of the patients at the time of surgery. Vascular reconstruction for late thrombosis was performed for 110 late occlusions in 103 patients. Included were 95 unilateral and 15 bilateral occlusions. The method of choice was graft limb thrombectomy (unilateral occlusion) or anatomical graft replacement (bilateral occlusion or unilateral occlusion when thrombectomy proved to be impossible). Associated outflow reconstructions consisted of profundaplasty in 73.3% of the cases. A mean yearly thrombosis rate of 9.4% (range 4-14%) resulted in a five year patency rate of 59%. Differences between graft thrombectomy and anatomical replacement were not statistically significant. Reconstruction for secondary occlusions was associated with a 25% thrombosis rate. Tertiary occlusion in six cases invariably led to major amputation. A total of 20 patients ultimately needed a major amputation, resulting in an eight year limb salvage rate of 79%.

Smoking: a decision-making dilemma for the vascular patient

This descriptive study examined the differences in beliefs and social influences between patients who decided to quit or to continue smoking following diagnosis of chronic peripheral vascular disease. A consecutive quota sample of 20 patients who had quit smoking (quitters) and 22 who had continued smoking (continuers) agreed to participate in the study. There were no statistically significant differences between quitters and continuers in demographic characteristics, clinical variables and perceived social influences. Statistically significant differences were found between groups in beliefs about and attitudes towards the risk of continued smoking. These findings underline the need to investigate more fully the factors which influence patients' decisions to quit or to continue smoking. Further investigation may also provide detailed information on the role of risk perception in influencing this decision-making process.

The effect of postoperative smoking on femoropopliteal bypass grafts

Effect of smoking habits on limb loss rates and cumulative patency rates of 136 arterial reconstructions performed for lower limb ischemia were analyzed in a five year follow-up retrospective study. Of 121 patients, 103 (85%) smoked before the operation and 43 of the smokers (42%) discontinued smoking postoperatively. Patients who continued to smoke more than 15 cigarettes per day (34 patients) increased the probability of losing their limb approximately five times at two years and three times at five years postoperatively, compared with nonsmokers and smokers of up to 15 cigarettes per day (87 patients) (p = 0.013). Cumulative patency rates of nonsmokers and smokers of up to five cigarettes per day (Group A, 66 patients) were not significantly influenced (p = 0.518) by preoperative symptoms (claudication versus limb salvage). However, for smokers of more than five cigarettes per day (Group B, 55 patients), at five years claudicants had a cumulative patency rate of 62.9% compared to 38.3% for limb salvage patients (p = 0.015). In group A at five years, autologous saphenous vein grafts had a cumulative patency rate of 74.2%, compared to 24% for prosthetic grafts (P = 0.013). In group B the CPR differences between autologous saphenous vein and prosthetic grafts were not significantly different (p = 0.394). Multiple interactions between smoking and variables like age, preoperative symptoms, and graft material demonstrate the complexity of the effects of smoking on cumulative patency rate and the need for sub-grouping and removal of confounding factors. In view of the adverse affects of continued smoking on postrevascularization prognosis, patients should be strongly advised to discontinue smoking.