Peripheral Arterial Disease in Octogenarians and Nonagenarians: Factors Predicting Survival

Peripheral Arterial Disease in Octogenarians and Nonagenarians: Factors Predicting Survival Ville k. Koskela,1 Juha Salenius,2 and Velipekka Suominen,2 Tampere, Finland

Background: To describe the prevalence and character of complications associated with revascularization procedures as a result of peripheral arterial disease in octogenarians and nonagenarians and to assess their overall survival depending on baseline characteristics, type of treatment modality, and possible procedure-related complications. A retrospective clinical study was carried out. Methods: A total of 383 patients aged >80 years, referred with suspected peripheral arterial disease, were categorized into octogenarians and nonagenarians. Data regarding cardiovascular risk factors, comorbidities, type of treatment, and possible procedure-related complications were collected from patients’ files. The cohort was followed up for total mortality until December 31, 2007, by means of record linkage with the National Causes of Death Register. Results: A total of 57 (14.9%) patients were treated surgically, whereas 71 (18.5%) underwent an endovascular procedure. Conservative treatment was chosen significantly more often for nonagenarians ( p ¼ 0.032). Postoperative complications (nonfatal, 13.2%; fatal, 3.1%) were equally distributed between the age groups and genders ( p ¼ 0.840 and p ¼ 0.820, respectively) but were significantly more common after surgical procedures ( p < 0.001 for both fatal and nonfatal complications). As expected, the overall survival was significantly poorer among nonagenarians as compared with octogenarians (33 vs. 45 months, respectively; p < 0.001). Older age, critical limb ischemia (CLI), and males were independently associated with mortality (odds ratio [OR]: 1.89, 95% confidence levels [CI]: 1.18-3.04; OR: 3.72, 95% CI: 2.34-5.91; and OR: 1.77, 95% CI: 1.10-2.80, respectively). The survival for nonagenarian men with CLI was 24 months and for women 28, regardless of the treatment modality. Conclusions: Octo- and nonagenarians seem to tolerate arterial reconstruction relatively well. Endovascular interventions should be favored over surgical procedures as they are associated with fewer complications. At the same time, the life expectancy of nonagenarians with CLI is limited to approximately 2 years, irrespective of the method of treatment. Further studies should be conducted to clarify the actual effect of vascular reconstructions among the elderly population with regard to benefits of both costs and quality of life.

INTRODUCTION The population of the world is aging. On the basis of the estimates of the United Nations, the number of 1

Tampere University, Faculty of Medicine Tampere, Finland.

2

Division of Vascular Surgery, Department of Surgery, Tampere University Hospital, Tampere, Finland. Correspondence to: Velipekka Suominen, PhD, Division of Vascular Surgery, Department of Surgery, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland, E-mail: [email protected] Ann Vasc Surg 2011; 25: 169-176 DOI: 10.1016/j.avsg.2010.07.016 Ó Annals of Vascular Surgery Inc. Published online: October 6, 2010

people around the world in the age group of 80 years is increasing rapidly.1 In Finland, the number of individuals aged >85 years has doubled in the last 20 years and is estimated to double again in the next two decades.2 Simultaneously, the number of centenarians will triple, and by the year 2040, the number of centenarians will have grown 5-fold.2 The prevalence of peripheral arterial disease (PAD) increases from the age of 50 onward and is in the range of 3-18%, increasing to 25-30% in persons aged >75 years.3,4 Regardless of the symptoms, PAD has been shown to associate with high cardiovascular mortality and morbidity as well as diminished quality of life.5-7 The published data on the prevalence and 169

170 Koskela et al.

outcome of PAD among the elderly population (above 90 years) are sparse. Available data suggest that the prevalence of PAD is approximately 20% among community-dwelling nonagenarians and that over 80% of them are asymptomatic.8 Patients with lifestyle-limiting intermittent claudication (IC) or critical limb ischemia (CLI) can be considered as candidates for revascularization, including both endovascular and surgical therapy. However, the choice of treatment should not depend only on the severity of the disease or the type of target lesion. Factors such as age and comorbidities should also be taken into consideration when planning treatment for individual patients. The information on the outcome of vascular procedures because of PAD among octogenarians is limited, and the data on nonagenarians are practically nonexistent.9,10 At the same time, the benefit of revascularization procedures among the elderly population may be of limited value because of an increased risk of cardiovascular events and complications in general.11,12 The objectives of the present study were (1) to describe the prevalence and character of complications associated with revascularization procedures because of PAD in octo- and nonagenarians, and (2) to assess the overall survival among them depending on baseline characteristics, the type of treatment modality, and possible complications related to revascularization procedures.

MATERIALS AND METHODS Study Population This is a retrospective analysis of consecutive patients referred to the vascular outpatient clinic at Tampere University Hospital (TAUH), Finland, between April 2002 and December 2006. Patients with suspected PAD were included in the study. The reasons for referral were categorized as follows: (1) IC; (2) pain when at rest, ulcer, or gangrene; and (3) nonspecified indication (coldness, numbness). TAUH serves a region with approximately 470,000 inhabitants, and all vascular surgical consultations, diagnostics, and procedures are performed exclusively at TAUH. Patients are referred to the outpatient clinic not only from the municipal health centers but also from regional cardiac, renal, and other units located within the TAUH district. Every patient visit to the hospital was recorded in the central register, along with the diagnosis and reason for attendance. An attempt to measure ankle brachial index (ABI) and toe brachial index (TBI) was made for all new admissions (N ¼ 2,654) during the study period. The pressure measurements were

Annals of Vascular Surgery

unsuccessful in 62 cases (2.3%) mainly because of patient-related factors, such as poor cooperation and noncompressible digital arteries. The target group for the present study comprised patients aged 80 years with successful measurements and who had not undergone vascular procedures for the lower extremity (N ¼ 471, 17.8%) (Fig. 1). According to age, patients were categorized into octogenarians (median: 82, interquartile range: 2 years; N ¼ 335) and nonagenarians (median: 89, interquartile range: 3 years; N ¼ 136). Those who were consequently found to have PAD were subjected to a detailed analysis (N ¼ 383, 81.3%). The need for ethical approval was waived off on the basis of the retrospective nature of the study. Risk Factors for PAD and other Comorbid Conditions Data from the patients’ files were collected systematically by two examiners (V.K. and V.S.). The following risk factors identified from case records were included in the analysis: age, gender, diabetes mellitus, hyperlipidemia, hypertension, smoking within 5 years, cardiovascular diseases other than PAD (coronary heart disease [CHD], cerebrovascular disease), respiratory disease, and chronic renal failure. The diagnosis for each disease was considered positive if it had been previously established at TAUH or mentioned in the referral, or if the patient was on appropriate medication. No distinction was made between chronic renal failure and end-stage renal disease. Measurement of ABI/TBI and Definitions ABI and TBI were measured using the Nicolet VasoGuard (Nicolet Vascular Inc, Madison, WI), a device that allows simultaneous systolic blood pressure measurements from the upper and lower extremities by means of photoplethysmography. Trained vascular nurses carried out all measurements by following the standard protocol (supine position, room temperature, after 10 minutes’ rest). Photoplethysmographic probes were attached to the tips of the big toes, and blood pressure cuffs of appropriate sizes were placed on the arms and legs above the ankle or at the base of the big toes. As a rule, values obtained from single ABI or TBI measurements of good quality were used. Because of the known association between subclavian stenosis and PAD,13 the higher of the two simultaneously measured brachial systolic blood pressure values was used in the analysis. ABI 0.9 was considered low, ABI >0.9 or <1.3 normal, and ABI 1.3 elevated. Patients with

Vol. 25, No. 2, February 2011

PAD in octogenarians and nonagenarians

171

471 patients referred

Patients without PAD N=88 Octogenarians N=69

Nonagenarians N=19

Patients with PAD N=383 Octogenarians N=266

Nonagenarians N=117

Conservative treatment N=168

Conservative treatment N=87

Endovascular treatment N=59

Endovascular treatment N=12

Surgical treatment N=39

Surgical treatment N=18

Fig. 1. Flow-chart of the patients aged 80 years and over referred to a vascular consultation. PAD, peripheral arterial disease.

an ABI 0.9 and/or TBI <0.60 in either leg were regarded as presenting with PAD. Revascularization Procedures and Postoperative Complications The type and character of revascularization procedures and postoperative complications were collected from patient case records as well as from the local vascular register (Table I). All surgical and endovascular interventions were analyzed both separately and as one entity. Patients visited the vascular outpatient clinic 4 weeks after discharge from the hospital. Possible surgical and nonsurgical complications were noted and registered in the local vascular register during the visit. Early failure of the revascularization (graft occlusion or thrombosis of the endovascularly treated segment within 30 days) was detected either by ultrasound or by a 0.15 decrease in ABI as compared with the postprocedural ABI. Death within 30 days after the intervention or in-hospital death was considered as postoperative death.

stroke, or PAD using appropriate International Classification of Disease-10 (ICD-10) codes (I20-I25, I46.1, I46.2, I63-I65, I70). Statistical Analysis SPSS 17.0 (for Windows) was used for statistical analysis (SPSS, Chicago, IL). For discrete variables, analyses were made with the aid of crosstabulations combined with c2-tests, and comparisons of means between the two groups were carried out with the t-test for independent samples. Logistic regression analysis was used to evaluate the independent association between total mortality and baseline characteristics, including the type of treatment modality and procedure-related complications. Survival analysis with the log-rank test was used to examine mortality according to gender, age, and the presence of CLI. A p value <0.05 was considered statistically significant.

RESULTS

Mortality

Baseline Characteristics and Postoperative Complications

The mortality follow-up data were available for up to 28 months (range: 0-68 months), until December 31, 2007. Because of a rather small sample size, only total mortality was analyzed during the study period. Deaths were ascertained by means of record linkage of the study data to the National Causes of Death Register, on the basis of the personal identification code unique to every resident in Finland. Cardiovascular (ischemic) death was defined as death because of CHD, myocardial infarction, sudden cardiac death,

A total of 383 (81.3 %) patients had PAD, with no significant difference between the age groups ( p ¼ 0.095). As demonstrated in Table II, the classical cardiovascular risk factors were significantly more common among octogenarians than their older counterparts. The reasons for referral among those who were consequently found to have PAD included IC 44.5%, CLI 44.2%, and nonspecified 11.3% for octogenarians; and 30.1%, 57.4%, and 12.5% for nonagenarians, respectively ( p ¼ 0.004, p ¼ 0.010, p ¼ 0.723,

172 Koskela et al.

Annals of Vascular Surgery

Table I. Vascular procedures performed in groups Octogenarians Nonagenarians

Surgical Aortoiliac/aortofemoral bypass Femoral endarterectomy Femoropopliteal (AK) bypass Femoropopliteal (BK) bypass Femorodistal bypass Extra-anatomic bypass Total Endovascular (PTA/S) Iliac Femoropopliteal Infrapopliteal Total Overall total

5

e

6 5

5 2

11

7

6 6 39

4 e 18

19 27 13 59 98

4 3 5 12 30

endovascular treatment was more common among octogenarians ( p ¼ 0.006) (Fig. 1). Generally, nonfatal complications after endovascular and surgical procedures were rare (17 patients [13.2%], 26 complications), with no significant difference between the age groups or genders ( p ¼ 0.840, p ¼ 0.820, respectively). However, complications were significantly more common after surgical procedures compared with endovascular interventions ( p < 0.001). The most common complication was postoperative bleeding (N ¼ 10), followed by early failure of the revascularization (N ¼ 5). Postoperative mortality was low as only four (three octogenarians and one nonagenarian, 3.1%) patients died within 30 days of the interventions (three patients from pneumonia, one from septicemia). All postoperative deaths occurred after surgical procedures ( p < 0.001). Longitudinal Analysis

AK, above knee; BK, below knee; PTA/S, percutaneous transluminal angioplasty/stenting.

Table II. Baseline characteristics of participants with PAD according to age (N ¼ 383) Measure

Gender (male) Diabetes mellitus Hyperlipidemia Hypertension Smoking CHD Cerebrovascular disease Respiratory disease Renal failure

Octogenarians Nonagenarians N ¼ 266 (%) N ¼ 117 (%) p valuea

117 100 53 166 32 103 32

(44) (38) (20) (62) (12) (39) (12)

30 (11) 12 (5)

38 27 13 59 3 57 14

(33) (23) (11) (50) (3) (49) (12)

0.035 0.005 0.035 0.028 0.003 0.068 0.986

14 (12) 5 (4)

0.846 0.917

c test.

a 2

respectively). Interestingly, approximately three in four of those who, according to our definitions, did not have PAD (N ¼ 88), presented with symptoms of either IC or critical ischemia. A total of 199 (52.0%) angiographies were performed, predictably mainly for CLI (N ¼ 135, 67.8%). According to the angiography results, 57 (14.9%) patients were thereafter treated surgically, whereas 71 (18.5%) underwent an endovascular procedure. Conservative treatment as a primary choice or after angiography evaluation was offered to the remaining 255 (66.6%) patients. Conservative treatment was chosen significantly more often for nonagenarians ( p ¼ 0.032), whereas

During the follow-up, 166 (43%) of the 383 patients with PAD died (Table III). The most common causes of death were ischemic cardiovascular diseases (43.9%) and diseases of the respiratory tract (18.1%). As expected, the overall survival was significantly poorer among nonagenarians as compared with octogenarians (33 vs. 45 months, respectively, p < 0.001). Mortality among those with PAD was further analyzed by performing regression analysis to assess the association of baseline characteristics with longterm survival. The variables included in the analysis were diabetes, hyperlipidemia, hypertension, CHD, cerebrovascular disease, respiratory disease, chronic renal failure, smoking, gender, age (octo-/nonagenarian), symptoms at presentation (CLI/non-CLI), the type of treatment chosen (conservative or endovascular or surgical), and procedure-related complications. Univarate analysis showed hyperlipidemia, hypertension, CLI, older age, and male gender significantly affecting the survival. On multivariate analysis, three factorsdCLI, older age, and male sex (OR: 3.72, 95% CI: 2.34-5.91; OR: 1.89, 95% CI: 1.18-3.04; OR: 1.77, 95% CI: 1.10-2.80, respectively)dwere found to be significantly associated with mortality (Table IV). At the same time, the presence of hypertension (OR: 0.63, 95% CI: 0.40-0.99) seemed to have a protective effect. When survival was assessed between the age groups depending on the presence of CLI, the survival was found to be significantly worse among those with CLI in both the age groups ( p < 0.001 for octogenarians and p ¼ 0.019 for nonagenarians) (Fig. 2). Survival among nonagenarians was further analyzed according to gender and the presence of CLI. As Figure 3

Vol. 25, No. 2, February 2011

PAD in octogenarians and nonagenarians

173

Table III. Causes of death of PAD patients during the follow-up (N ¼ 166) Cause of death

Octogenarians N ¼ 101 (%)

Nonagenarians N ¼ 65 (%)

p value

Infectious diseases Neoplasms Endocrine and metabolic diseases Mental and behavioral disorders Diseases of the nervous system Cardiovascular diseasesa Nonischemic circulatory diseases Diseases of the respiratory system Diseases of the digestive system Diseases of the musculoskeletal system Diseases of the genitourinary system Trauma Nonspecified

1 5 3 1 3 45 8 21 3 1 3 4 3

3 3 1 1 4 28 10 10 2 0 2 0 1

0.137 0.922 0.557 0.752 0.319 0.852 0.131 0.383 0.969 0.421 0.969 0.104 0.557

(1.0) (5.0) (3.0) (1.0) (3.0) (44.6) (7.9) (20.8) (3.0) (1.0) (3.0) (4.0) (3.0)

(4.6) (4.6) (1.5) (1.5) (6.2) (43.1) (15.4) (15.4) (3.1) (0) (3.1) (0) (1.5)

a Cardiovascular death was defined as death due to coronary heart disease, myocardial infarction, sudden cardiac death, stroke or peripheral arterial disease, using the appropriate International Classification of Disease-10 (ICD-10) codes (I20eI25, I46.1, I46.2, I63eI65, I70).

Table IV. The odds ratio (95% CI) for mortality among those with PAD during the follow-up: multivariate analysis (Logistic regression model) Measure

OR

95% CI

p value

Hyperlipidemia Hypertension Gender (male) Age (nonagenarian) CLI

0.56 0.64 1.77 1.89 3.72

0.30-1.06 0.41-0.99 1.10-2.80 1.18-3.04 2.34-5.91

0.072 0.047 0.018 0.09 <0.001

demonstrates, women without CLI had the longest survival (mean: 49 months) as compared with all three other groups ( p ¼ 0.023 for men with CLI [mean: 25 months], p ¼ 0.051 for men without CLI [mean: 34 months], p ¼ 0.006 for women with CLI [mean: 28 months]).

DISCUSSION The prevalence of PAD among octo- and nonagenarians referred to a vascular consultation was high (81.3%). Cardiovascular risk factors were significantly more common among octogenarians than their older counterparts. Regardless of this, and of the fact that nonagenarians presented predominantly with CLI, conservative treatment was chosen more often for nonagenarians. Procedure-related complications were rare and equally distributed between the age groups and genders. However, complications were significantly more common after surgical procedures compared with endovascular interventions. Predictably, overall mortality was significantly higher among nonagenarians than octogenarians. In

addition to older age, factors that were independently associated with mortality included CLI and male gender. Even though the population is aging, the prevalence and significance of PAD among octo- and nonagenarians have attracted little interest. According to the published data, the prevalence of PAD (defined as ABI <0.9) among octogenarians ranges between 32% and 47% in men and 28-51% in women.3,4 It has also been suggested that the overall prevalence of IC among octogenarians is approximately 5%. The corresponding figures for nonagenarians are 22% and 8%, respectively, as demonstrated in our earlier study.8 There are no previous publications comparing cardiovascular risk factor profiles among octo- and nonagenarians. The prevalence of comorbid diseases among octogenarians in this study concurs with the results of previous reports.10,11,14 Furthermore, an earlier publication on octo- and septuagenarians suggests that younger PAD patients have more comorbid diseases, which is confirmed by our current results.15 However, in most recent studies that have looked into different aspects of health, the elderly population appear to be more ill than the younger generations.16-18 Like any other intervention, surgical and endovascular procedures for PAD are associated with postoperative complications that may cause human suffering in the forms of pain, prolonged hospital stays, as well as increased costs. In a recent study by Flu et al., it was observed that postoperative complications are actually responsible for a third of the total revascularization-related costs.19 The incidence of postoperative morbidity and mortality varies substantially in different studies and is in

174 Koskela et al.

N at risk 138 128 49 68

Annals of Vascular Surgery

105 73 29 36

47 21 10 10

13 5 3 1

80 – CLI 80 + CLI 90 – CLI 90 + CLI

Fig. 2. Survival of peripheral arterial disease patients depending on age and symptoms at the time of presentation. KaplaneMeier survival analysis. SEM >10% among nonagenarians without critical limb ischemia at 45 months.

the range of 3-30%.12,19-22 The study further suggested that there is a significant advantage of complications for endovascular interventions as compared with traditional surgery. Factors usually associated with higher complication rates include diabetes, CLI, CHD, acute surgery, and cerebrovascular disease, whereas the most frequent complications were postoperative hemorrhage, infection and early failure of the vascular graft.22-25 Advanced age seemed to be another risk factor for postoperative complications.12,14,26 For example, in their study on 619 consecutive patients undergoing endovascular treatment for PAD, Dick et al. found that octogenarians had a 10.99-fold increase adjusted risk for major complications as compared with their younger counterparts.12 However, Choi et al. reported no difference in nonfatal (approximately 15%) complications between older and younger subjects undergoing infrainguinal reconstruction for PAD.27 In our cohort, 13.2% of the patients had a nonfatal and 3.1% a fatal postoperative complication. The relatively low complication rate is probably explained by the selection bias, that is, the predominant choice of conservative treatment, especially for nonagenarians. PAD has been associated with increased total and cardiovascular mortality in both clinical and community settings.6,28,29 Recently, Vartjees et al., in a study similar to ours, reported a 10.4% mortality risk at 1 year and an approximately 30% risk at 5 years among 4,158 patients admitted to hospital for the first time for the treatment of PAD.29 The authors concluded that the mortality is

comparable with that of patients admitted for acute myocardial infarction or ischemic stroke. In a subgroup of patients aged >85 years, the mortality risk was 44% at 1 year and 78% at 5 years. Mortality was found to be higher among men and statistically significant at 5 years. Our corresponding respective rates were 15% and 57% for octogenarians and 26% and 75% for nonagenarians. The lower mortality in the current series probably reflects the difference in the study designs: Vaartjes analyzed hospitalized patients, whereas we studied outpatients with presumably less severe disease. The most common cause of death in both Vaartjes’ study and the current study was cardiovascular disease (52% and 44%, respectively). The available data published on octogenarians and nonagenarians suggest that arterial reconstruction should not be ruled out on the basis of patient age alone.10,11,14,26 Endovascular interventions as minimally invasive and with lower complication rates are usually advocated over surgical procedures. Our results, with significantly more complications associated with surgical procedures, support this general impression. However, these studies have limitations such as short follow-up, small number of nonagenarians enrolled, and the lack of quality of life measures. According to the results of this study, the overall survival for nonagenarians (mean age: 89 years) was 33 months, but for men with CLI, it was only 25 months and for women 28 months, regardless of the method of initial treatment. At the same time, the life expectancy for the general population at 89 years in Finland was 4 years

Vol. 25, No. 2, February 2011

PAD in octogenarians and nonagenarians

175

Fig. 3. Survival among nonagenarians depending on sex and symptoms at presentation. KaplaneMeier survival analysis.

for men and 4.5 years for women.30 Consequently, as the type of treatment does not seem to affect the overall survival of nonagenarians with CLI, surgeons should be careful when selecting patients for arterial reconstruction, and, above all, they should be convinced of the benefits with regard to the quality of life for an individual patient. There are several limitations to this study, the main drawback being the retrospective design involving possible data issues associated with the use of hospital discharge histories and patient case records. However, the multiple admissions of the subjects to our hospital because of comorbidities before the initiation of the current study made data collection easier and, we believe, more accurate. Furthermore, possible data errors and miscoding will be similar for both groups. The second limitation is the relatively small number of nonagenarians (N ¼ 117), especially those who underwent endovascular or surgical treatment (N ¼ 30), which may limit the statistical validity of our findings. In contrast, the Causes of Death Register maintained by Statistics Finland contains data from death certificates completed either by physicians who treated the patients, or, in case of unclear or unnatural deaths, by the physician who performed the autopsy. The register includes all deaths of the citizens and permanent residents of Finland. As it is

possible to ascertain deaths on the basis of the unique personal identification code, the data in this study can be considered reliable in this respect. Another potential issue is the relatively short duration of the follow-up, which could have an effect on the results.

CONCLUSIONS According to the results of this study, octo- and nonagenarians seem to tolerate arterial reconstruction, especially endovascular interventions, relatively well. At the same time, the life expectancy of nonagenarians with CLI is limited to approximately 2 years irrespective of the method of treatment. Therefore, surgeons should be convinced that the planned intervention for an individual patient will have a positive effect on the quality of life. Further studies should be conducted to clarify the actual effect of vascular reconstructions among the elderly population with regard to both costs and quality of life.

This study was financially supported by the Competitive Research Funding of the Pirkanmaa Hospital District, Tampere University Hospital.

176 Koskela et al.

REFERENCES 1. World Population Ageing 1950-2050 (2002): United Nations, Department of Economic and Social Affairs, Population Division. Available at http://www.un.org/esa/population/publi cations/worldageing19502050/. 2. Statistics Finland. Population structure. Available at http:// www.tilastokeskus.fi/til/vaerak/tau_en.html. Referred on December 17, 2008. 3. Diehm C, Schuster A, Allenberg JR, et al. High prevalence of peripheral arterial disease and co-morbidity in 6880 primary care patients: cross-sectional study. Atherosclerosis 2004;172: 95-105. 4. Meijer WT, Hoes AW, Rutgers D, et al. Peripheral arterial disease in the elderly. Arterioscler Thromb Vasc Biol 1998;18:185-192. 5. Hirsch AT, Criqui MH, Treat-Jacobson D, et al. Peripheral arterial disease detection, awareness, and treatment in primary care. JAMA 2001;286:1317-1324. 6. Lee AJ, Price JF, Russell MJ, et al. Improved prediction of fatal myocardial infarction using the ankle brachial index in addition to conventional risk factors: the Edinburgh Artery Study. Circulation 2004;110:3075-3080. 7. de Vries M, Ouwendijk R, Kessels AG, et al. Comparison of generic and disease-specific questionnaires for the assessment of quality of life in patients with peripheral arterial disease. J Vasc Surg 2005;41:261-268. 8. Suominen V, Rantanen T, Heikkinen E, Venermo M, Salenius J. Peripheral arterial disease and its clinical significance in nonagenarians. Aging Clin Exp Res 2008;20:211-215. 9. Taylor SM, Kalbaugh CA, Blackhurst DW, et al. Postoperative outcomes according to preoperative medical and functional status after infrainguinal revascularization for critical limb ischemia in patients 80 years and older. Am Surg 2005;71:640-645. 10. Salas CA, Adam DJ, Papavassiliou VG, London NJ. Percutaneous transluminal angioplasty for critical limb ischaemia in octogenarians and nonagenarians. Eur J Vasc Endovasc Surg 2004;28:142-145. 11. Brosi P, Dick F, Do DD, et al. Revascularization for chronic critical lower limb ischemia in octogenarians is worthwhile. J Vasc Surg 2007;46:1198-1207. 12. Dick P, Barth B, Mlekusch W, et al. Complications after peripheral vascular interventions in octogenarians. J Endovasc Ther 2008;15:383-389. 13. Shadman R, Criqui MH, Bundens WP, et al. Subclavian artery stenosis: prevalence, risk factors, and association with cardiovascular diseases. J Am Coll Cardiol 2004;44:618-623. 14. Dosluoglu HH, Lall P, Cherr GS, Harris LM, Dryjski ML. Superior limb salvage with endovascular therapy in octogenarians with critical limb ischemia. J Vasc Surg 2009;50:305-315. 15. Chang JB, Stein TA. Infrainguinal revascularizations in octogenarians and septuagenarians. J Vasc Surg 2001;34: 133-138.

Annals of Vascular Surgery

16. von Strauss E, Fratiglioni L, Viitanen M, Forsell Y, Winblad B. Morbidity and comorbidity in relation to functional status: a community-based study of the oldest old (90+ years). J Am Geriatr Soc 2000;48:1462-1469. 17. von Heideken Wa˚gert P, Gustavsson JM, Lundin-Olsson L, et al. Health status in the oldest old. Age and sex differences in the Umea˚ 85+ Study. Aging Clin Exp Res 2006;18: 116-126. 18. Weyerer S, Eifflaender-Gorfer S, Ko¨hler L, et al German AgeCoDe Study group (German Study on Ageing, Cognition and Dementia in Primary Care Patients). Prevalence and risk factors for depression in non-demented primary care attenders aged 75 years and older. J Affect Disord 2008;111: 153-163. 19. Flu H, van der Hage JH, Knippenberg B, et al. Treatment for peripheral arterial obstructive disease: an appraisal of the economic outcome of complications. J Vasc Surg 2008;48: 368-376. 20. Black JH III, LaMuraglia GM, Kwolek CJ, et al. Contemporary results of angioplasty-based infrainguinal percutaneous interventions. J Vasc Surg 2005;42:932-939. 21. LaMuraglia GM, Conrad MF, Chung T, et al. Significant perioperative morbidity accompanies contemporary infrainguinal bypass surgery: an NSQIP report. J Vasc Surg 2009;50:299-304. 22. Nowygrod R, Egorova N, Greco G, et al. Trends, complications, and mortality in peripheral vascular surgery. Trends, complications, and mortality in peripheral vascular surgery. J Vasc Surg 2006;43:205-216. 23. Roddy SP, Darling RC III, Maharaj D, et al. Gender-related differences in outcome: an analysis of 5880 infrainguinal arterial reconstructions. J Vasc Surg 2003;37:399-402. 24. Schepers A, Klinkert P, Vrancken Peeters MP, Breslau PJ. Complication registration in patients after peripheral arterial bypass surgery. Ann Vasc Surg 2003;17:198-202. 25. Lange CP, Ploeg AJ, Lardenoye JW, Breslau PJ. Patient- and procedure-specific risk factors for postoperative complications in peripheral vascular surgery. Qual Saf Health Care 2009;18:131-136. 26. Matsubara J, Sakamoto S, Shikata H, et al. Is arterial surgery advisable for patients over 80 years of age? J Cardiovasc Surg (Torino) 2001;42:375-379. 27. Choi D, Darling RC III, Roddy SP, et al. Infrainguinal reconstruction in octogenarians: should age be a contraindication? Ann Vasc Surg 2000;14:67-72. 28. McDermott MM, Feinglass J, Slavensky R, Pearce WH. The ankle-brachial index as a predictor of survival in patients with peripheral vascular disease. J Gen Intern Med 1994;9: 445-449. 29. Vaartjes I, de Borst GJ, Reitsma JB, et al. Long-term survival after initial hospital admission for peripheral arterial disease in the lower extremities. BMC Cardiovasc Disord 2009;9:43. 30. Statistics Finland. Population structure. Available at http:// www.tilastokeskus.fi/til/kuol/2007/kuol_2007_2008-1107_tau_004.xls. Referred on December 17, 2008.