A prospective survey of risk factors in young adults with arterial occlusive disease

Early-onset peripheral arterial occlusive disease: clinical features and determinants of disease severity and location

Early-onset peripheral lower extremity arterial occlusive disease (PAD) is an uncommon, poorly characterized manifestation of atherosclerotic vascular disease. We studied the clinical presentation and correlates of disease severity and location in patients with early-onset PAD identifi ed at non-invasive arterial evaluation. We identifi ed a series of 159 patients who were younger than 50 years and had an abnormal resting or postexercise ankle brachial index (ABI) (<0.9) or, if arteries were noncompressible, monophasic arterial Doppler signals. Disease severity and location were determined based on results of noninvasive vascular laboratory testing. Presence of coexisting atherosclerosis in other arterial beds was ascertained by review of patient records. Multivariable logistic regression analyses were used to identify risk factors associated with disease severity and location. Mean age of the patients was 42.7 6 4.2 years and 55% were women. Prevalence of risk factors was 76% for current or past smoking; 71%, dyslipidemia; 53%, hypertension; 35%, diabetes; and 53%, family history. Claudication was present in 50%, rest pain in 3%, ulceration in 31% and the remaining 16% did not have symptoms from PAD. Low high-density lipoprotein (HDL)-cholesterol and female sex were associated with severity. Of 102 patients in whom disease location could be determined noninvasively, 65% had aortoiliac disease. Female sex, low HDL-cholesterol, and absence of diabetes were associated with aortoiliac disease. Atherosclerosis in other arterial beds was identifi ed in 53% of the patients. Conclusion: In this study population of early-onset atherosclerotic PAD, men and women were equally represented. The disease involved predominantly the aortoiliac location. Low HDL-cholesterol and female sex were associated with disease severity. An aggressive approach to diagnosis and treatment may be warranted as atherosclerosis in other arterial beds was prevalent in half of the patients.

Lower Extremity Amputations in Adults Less Than Forty Years of Age: An Underestimated Risk from Premature Atherosclerosis

Between 1987 and 1992, 57 patients aged twenty-five to forty (average, 34.0 ±4.5 years) underwent major lower extremity amputations in five community hospitals, including a Level II Trauma Center. Only 19 (33%) patients had traumatic amputations, 3 (5%) had malignant tumors, and 4 (7%) had juvenile-onset diabetes mellitus without atherosclerotic involvement of the large arteries. Thirty (53%) patients had premature atherosclerosis (PAS) of the lower extremities with end-stage renal disease (ESRD) present in half and related to diabetes in 12. All patients with ESRD required continuous dialysis therapy. Overall 19 (33%) patients in this study had diabetes. Of 32 patients < thirty-five years of age, 47% had traumatic amputations, and PAS was diagnosed in 28%. However, PAS was diagnosed in 84% of 25 patients > thirty-six years of age (OR= 14.3; P < 0.001). In total, 67 amputations were done. Twenty-one (68%) of 31 above-knee amputations (AKA) were performed in patients with PAS, and 26% of AKA were related to trauma. Of 10 bilateral amputations, 9 (90%) were done in patients with PAS. Patients with PAS had a high prevalence of risk factors for cardiovascular disease including smoking (87%), diabetes (50%), hypertension (50%), and hyperlipidemia (30%). Nine (30%) of the patients with PAS had hypercoagulable states. PAS was identified as the leading cause for major amputations among young adults in this community and was frequently associated with heavy smoking, diabetes, end-stage renal disease, and hypercoagulability.

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.

Cardiovascular risk factors and collateral artery formation

Arterial lumen narrowing and vascular occlusion is the actual cause of morbidity and mortality in atherosclerotic disease. Collateral artery formation (arteriogenesis) refers to an active remodelling of non-functional vascular anastomoses to functional collateral arteries, capable to bypass the site of obstruction and preserve the tissue that is jeopardized by ischaemia. Hemodynamic forces such as shear stress and wall stress play a pivotal role in collateral artery formation, accompanied by the expression of various cytokines and invasion of circulating leucocytes. Arteriogenesis hence represents an important compensatory mechanism for atherosclerotic vessel occlusion. As arteriogenesis mostly occurs when lumen narrowing by atherosclerotic plaques takes place, presence of cardiovascular risk factors (e.g. hypertension, hypercholesterolaemia and diabetes) is highly likely. Risk factors for atherosclerotic disease affect collateral artery growth directly and indirectly by altering hemodynamic forces or influencing cellular function and proliferation. Adequate collateralization varies significantly among atherosclerotic patients, some profit from the presence of extensive collateral networks, whereas others do not. Cardiovascular risk factors could increase the risk of adverse cardiovascular events in certain patients because of the reduced protection through an alternative vascular network. Likewise, drugs primarily thought to control cardiovascular risk factors might contribute or counteract collateral artery growth. This review summarizes current knowledge on the influence of cardiovascular risk factors and the effects of cardiovascular medication on the development of collateral vessels in experimental and clinical studies.

[Thrombophilias and peripheral arterial occlusive disease]

Peripheral arterial occlusive disease is a frequent disease due to the classical vascular risk factors such as smoking, diabetes mellitus, dyslipidemia, and hypertension. Despite these risk factors, many thrombophilias (physiological inhibitors defects, Factor V Leiden and 20210A prothrombin gene variant, antiphospholipid antibodies, mild hyperhomocysteinemia 15-30micromol/l) can be evoked in some clinical forms of peripheral arterial occlusive disease. This paper provides a synthesis of the published data about this topic. Screening for these thrombophilias is justified in patients with venous thromboembolic disease, or signs of antiphospholipid syndrome and possibly in different situations such as premature atheroma of lower limbs, chronic ischaemia, evolutive disease despite adapted treatment and revascularisation failures without evident technical explanation. Except for the antiphospholipid syndrome, there is currently no consensus for systematic screening of thrombophilia and treatment in patients with peripheral arterial occlusive disease.

Impact of genetic background and aging on mesenteric collateral growth capacity in Fischer 344, Brown Norway, and Fischer 344 x Brown Norway hybrid rats

Available studies indicate that both genetic background and aging influence collateral growth capacity, but it is not known how their combination affects collateral growth. We evaluated collateral growth induced by ileal artery ligation in Fischer 344 (F344), Brown Norway (BN), and the first generation hybrid of F344 x BN (F1) rats available for aging research from the National Institute on Aging. Collateral growth was determined by paired diameter measurements in anesthetized rats immediately and 7 days postligation. In 3-mo-old rats, significant collateral growth occurred only in BN (35% +/- 11%, P < 0.001). The endothelial cell number in arterial cross sections was also determined, since this precedes shear-mediated luminal expansion. When compared with the same animal controls, the intimal cell number was increased only in BN rats (92% +/- 21%, P < 0.001). The increase in intimal cell number and the degree of collateral luminal expansion in BN rats was not affected by age from 3 to 24 mo. Immunohistochemical studies demonstrated that intimal cell proliferation was much greater in the collaterals of BN than of F1 rats. The remarkable difference between these three strains of rats used in aging research and the lack of an age-related impairment in the BN rats are novel observations. These rat strains mimic clinical observations of interindividual variation in collateral growth capacity and the impact of age on arteriogenesis and should be useful models to investigate the molecular mechanisms responsible for such differences.

The prevalence of thrombophilia in patients with symptomatic peripheral vascular disease

Background

The aim of this prospective study was to establish the prevalence of thrombophilia and hyperhomocysteinaemia using a comprehensive screen in patients with peripheral vascular disease.

Methods

A total of 150 patients with peripheral vascular disease (with an ankle brachial pressure index of less than 0·8) underwent thrombophilia screening (protein C and protein S, antithrombin, lupus anticoagulant, activated protein C resistance and factor V Leiden and prothrombin mutations). Fasting homocysteine assays were also performed.

Results

A thrombophilia defect was found in 41 patients (27·3 per cent). The commonest was protein S deficiency, found in 17 patients (11·3 per cent). Others included factor V Leiden mutation, found in 10 (6·7 per cent) and protein C deficiency, found in six (4·0 per cent). Lupus anticoagulant and prothrombin mutation were both found in six (4·0 per cent). One patient had an antithrombin deficiency. Only the presence of critical ischaemia was associated with a positive thrombophilia screen on single variable analysis (P = 0·03). Hyperhomocysteinaemia was present in over a third of the study group (37·3 per cent): 45 defined as moderate and 11 as intermediate.

Conclusion

A quarter of patients with peripheral vascular disease had evidence of thrombophilia, and a third had hyperhomocysteinaemia.

Prevalence and Risk of Thrombophilia Defects in Vascular Patients

This paper reviews the available data on the prevalence of thrombophilia defects in patients with peripheral vascular disease (PVD) and attempts to delineate the risk of failure of vascular intervention in these patients. The prevalence of thrombophilia in stable claudicants is 25% and increases to 40% in those requiring revascularisation, compared to only 11% in the control group. The overall prevalence of thrombophilia defects in patients with premature atherosclerosis appears to be between 15 and 30%. The prevalence in the typical cohort of patients with PVD appears to be similar. All these studies have recruited patients with symptoms significant enough to warrant intervention. The overall prevalence of thrombophilia calculated from these trials, therefore, may not be truly indicative of the general vascular population who may not even present primary or secondary healthcare. The risk of thrombotic occlusion following arterial revascularisation in patients with an identified thrombophilia defect appears to be almost three times that of patients with no evidence of a thrombophilia defect. The best management of these patients has not been determined and needs to be evaluated by prospective randomized trials.

Premature lower extremity atherosclerosis: clinical aspects

Peripheral arterial disease (PAD) involving the lower extremities is presumably a disease of the elderly. The awareness of PAD in the general population, and in younger adults in particular, is low. Atherosclerosis is the major cause of lower limb ischemia in the young. Young adults with clinical manifestations of premature lower extremity atherosclerosis (PLEA) typically have multiple cardiovascular risk factors and the majority are smokers, with strong family history of cardiovascular disease, and typically have chronic symptoms of claudication at diagnosis. Frequently these symptoms are either not reported in a timely manner by the patients or are attributed to other, presumably more common causes of leg pain in the young. More than 70% of patients with PLEA have angiographic evidence of severe aortoiliac disease. The results of surgical revascularizations in young adults are inferior to those reported in older patients. Younger adults typically require multiple revascularizations with relatively high amputation rate. We conclude that PAD should be considered in adults with multiple risk factors regardless of their age if appropriate symptoms are present. There is a need for increased public health awareness for premature lower extremity atherosclerosis.

Risk factors for premature atherosclerosis

OBJECTIVES

to investigate the prevalence of risk factors in patients with premature atherosclerosis.

DESIGN

retrospective controlled study.

MATERIALS

135 consecutive patients with premature atherosclerosis </= 55 years (group I) were investigated. A control group comprised 107 consecutive patients >/= 65 years (group II) with atherosclerosis. Statistical analysis was performed with Chi-squared test and logistic regression analysis.

RESULTS

group I versus group II: diabetes 11% vs. 27% (p=0.001), smoking 84% vs. 67% (p=0.002), hypertension 36% vs. 58% (p=0.001), hypercholesterolaemia 47% vs. 34% (p=0.04), family history of cardiovascular disease 53% vs. 42% (p=0.08). In group I hyperhomocysteinaemia was present in 24 of the 108 patients tested, anticardiolipin antibodies were present in four of the 34 tested and coagulation abnormalities were found in four of the 22 patients tested.

CONCLUSION

the difference in the prevalence of the different risk factors between the two groups suggests that either certain risk factors are more likely to cause premature atherosclerosis, or that other risk factors must be present in addition to the known risk factors in order to induce premature atherosclerosis.

Hypercoagulable abnormalities and postoperative failure of arterial reconstruction

OBJECTIVES

To determine whether preoperative hypercoagulable abnormalities are independent risk-factors for the failure of arterial reconstruction in leg ischaemia.

METHODS

Sixty consecutive patients were studied before, and for 1 year following, elective peripheral revascularisation. Antithrombin III, protein C and protein S levels, and tests for lupus anticoagulant were performed preoperatively, and then repeated on the first and third postoperative days and after 1 and 6 months. Heparin-associated thrombocytopenia was also investigated if there was a postoperative fall in platelet count greater than 100 x 10(9)/l.

RESULTS

Forty-six (77%) procedures were performed for critical ischaemia and 15 (25%) involved infrapopliteal reconstruction. The nature of surgery or accepted risk factors for occlusion were comparable between the 40 (67%) patients with patent reconstructions at 1 year and the 20 (33%) who had suffered failure. Preoperative hypercoagulable abnormalities were detected in 21 (35%) patients, with a three times greater incidence in those whose reconstructions failed (65% vs. 20%, p < 0.01), and in 11 of 12 patients suffering early (within 1 month) occlusion. The lupus anticoagulant was more frequently detected when prosthetic grafts were already present (p < 0.05) and carried a positive predictive value for reocclusion of 67% (p < 0.01). All three postoperative deaths occurred in patients with low protein S levels before surgery.

CONCLUSIONS

Hypercoagulable abnormalities are common prior to arterial revascularisation and are independently associated with subsequent failure.

Late outcome of amputees with premature atherosclerosis

BACKGROUND

Peripheral atherosclerosis in young adults has been associated with a high amputation rate. Our purpose was to examine the natural history of amputees with premature atherosclerosis.

METHODS

We compared 50 consecutive young patients undergoing dysvascular amputation who were 49 years of age or younger (mean age +/- SEM, 43 +/- .7 years) with 75 consecutive men and women ranging in age from 60 to 75 years (mean age, 67 +/- .6 years) who were undergoing major amputations for atherosclerosis during the same period.

RESULTS

Before undergoing amputation 46 (92%) patients in the study group underwent a mean of 3 +/- 0.3 vascular operations, and 49 (65%) older patients in the control group underwent a mean of 2 +/- 0.2 vascular operations (p = 0.003). The mean time from onset of symptoms to first amputation was not different in the study group versus the control group. Of those patients surviving until discharge, 20 (45%) patients in the study group and 21 (31%) patients in the control group became community or household ambulators, whereas 24 (55%) patients in the study group and 47 (69%) patients in the control group were confined to wheelchairs or were bedridden (p = 0.17). Seventeen (74%) patients in the study group who did not require contralateral amputations became community ambulators, as did 18 (38%) members of the control group (p = 0.01). Twenty (40%) patients in the study group and 39 (52%) patients in the control group died during the study period. The mean age at death was 48 +/- 1 years for the study group and 69 +/- .8 years for the control group (p < 0.001). Cumulative 5-year survival (62% patients in study group, 47% patients in control group) was not different between the two groups (p = 0.41, Kaplan-Meier).

CONCLUSIONS

Compared with older counterparts, amputees with premature atherosclerosis have a higher number of failed bypasses before undergoing amputation and die at a younger age. However, both groups have a similar cumulative survival after amputation. Fewer than one half of young patients undergoing dysvascular amputation ultimately achieve ambulation, suggesting that major amputations are a harbinger of long-term disability and dependency in these patients. Because young patients had a higher potential for rehabilitation after unilateral amputation, these patients should be monitored closely for development of ischemia in the contralateral limb.

Long-term follow-up of patients with early atherosclerosis

PURPOSE

Patients with premature peripheral vascular disease may respond differently than their older counterparts. To determine the impact of early onset of atherosclerosis on outcome, we decided to compare a group of these patients with a group of patients with typical onset of atherosclerosis with regard to early complications, indications for intervention, site of disease at initial presentation (aortoiliac, infrainguinal, or cerebrovascular), and long-term outcomes (secondary revascularization, amputation, and death).

METHOD

All patients younger than 50 years old requiring operative intervention between 1987 and 1992 were retrospectively compared with a group of patients greater than 60 years old, randomly selected from patients who underwent operation during the same time period. Patients were evaluated and compared for indications, risk factors, and early and late outcomes.

RESULTS

Patients with early onset atherosclerosis at the aortoiliac or infrainguinal level had a higher late amputation rate (17% versus 3.9%, p = 0.02) and poorer overall outcome than their older cohorts. Patients with cerebrovascular disease in both cohorts had similarly good prognoses.

CONCLUSION

Aortoiliac or infrainguinal disease diagnosed in patients less than 50 years of age portends a poorer outcome than does similar disease in an older patient population.

A prospective evaluation of atherosclerotic risk factors and hypercoagulability in young adults with premature lower extremity atherosclerosis

PURPOSE

Fifty-one consecutive patients with premature lower extremity atherosclerosis were prospectively evaluated for atherogenic risk factors and primary or acquired hypercoagulability, which might contribute to early ischemia and revascularization failure.

METHODS

Laboratory tests included plasma assays of (1) natural anticoagulants (NAC), lipoprotein (a) (Lp[a]), and anticardiolipin antibodies, and (2) fibrinolytic activators and inhibitors at baseline and stimulated after 20 minutes of upper extremity venous occlusion.

RESULTS

Forty-six (90%) of these 51 patients had laboratory abnormalities. One or more NAC deficiencies were found in 15 (30%) patients and included antithrombin III (n = 5), protein C (n = 8), protein S (n = 4), and heparin cofactor II (n = 2). Hypofibrinolysis was identified as a deficiency of stimulated tissue plasminogen activator in 22 (45%) patients and elevated plasminogen activator inhibitor-1 (PAI-1) in 29 (59%). Elevated Lp(a) was found in 43 (86%) patients. Five (10%) patients had anticardiolipin antibodies. Ten patients had combined NAC deficiency and hypofibrinolysis. Five (10%) patients had no abnormality. NAC deficiencies, especially protein C deficiency, were associated with acute ischemia (p < 0.01), prior vascular intervention (p < 0.01), an increasing number of total vascular procedures (p < 0.01), and major amputation (p < 0.01). PAI-1 was associated with a history of heart disease (p < 0.05) and prior vascular procedures (p < 0.05). Elevated Lp(a) was associated with elevated PAI-1 (p < 0.05). Retesting in 20 patients suggested that 80% of NAC deficiencies were acquired, but abnormalities persisted in 66% of patients with elevated PAI-1 and in 93% of those with elevated Lp(a).

CONCLUSIONS

These data strongly support the hypothesis that the convergence of atherogenic risk factors and hypercoagulability play an important role in early ischemia and poor results reported for lower extremity vascular procedures in young adults.

Results of vascular reconstructions for atherosclerotic arterial occlusive disease of the lower limbs in young adults

OBJECTIVE

To evaluate early and long-term results of vascular reconstructions for arterial atherosclerotic occlusive disease (AOD) of the lower limb in young patients under the age of 40 years.

DESIGN

Retrospective study.

SETTING

University hospital.

MATERIALS

Twenty-nine young adults, who underwent vascular reconstruction for histologically proven AOD of the aortoiliac and/or femoropopliteal segments in a 15-year period.

CHIEF OUTCOME MEASURES

Early and late mortality, failure of vascular reconstructions, additional procedures, other manifestations of atherosclerosis, recurrence of symptoms.

MAIN RESULTS

Nine patients (31%) died, seven related to atherosclerotic disease. In 21 patients (72%) initial vascular reconstruction(s) failed. Twenty-two patients (76%) underwent surgery for failures and/or progression of AOD in other segments of the lower limb. Amputation was performed in five patients (17%). At the end of the follow-up period only 25% of surviving patients were asymptomatic.

CONCLUSION

Young patients undergoing vascular reconstructions for AOD of the lower limbs, in particular those who initially have extensive and progressive atherosclerosis, have a poor outcome in terms of a high mortality and a high operative failure rate. A liberal attitude towards reconstructive surgery, particularly in claudication, is not warranted.

Percutaneous transluminal angioplasty in adults less than 45 years of age with premature lower extremity atherosclerosis

Despite poor results reported with conventional vascular bypasses in young adults with ischemia from premature lower extremity atherosclerosis (PLEA), little attention has been given to alternative revascularization techniques. This study evaluated 32 patients (21 males and 11 females) < 45 years of age with PLEA who underwent 53 primary percutaneous transluminal angioplasty (PTA) procedures for treatment of 46 ischemic limbs. A residual arterial stenosis < 30% was achieved in 83% of PTA sites. Mean degree of stenosis decreased from 79.9% to 24.1% (p < 0.0001). Clinical improvement in ischemic symptoms was obtained in 39 (85%) limbs. Hemodynamic improvement was achieved in 31 (70%) of 40 limbs as documented by ankle/brachial indices. All criteria for early clinical success were met in 70%. Another 13% met all criteria except that the residual stenosis was < 50%. Hematoma and early restenosis were reported in two patients each. Mean follow-up was 27.3 months (range 1 to 84 months). Cumulative patency by life-table analysis was 81% at 1 year, 77% at 2 years, and 71% at 3 years. Thirteen (41%) patients required secondary PTA or bypass; 85% were performed within 1 year. Two patients had adjunctive bypasses; six (19%) were performed after PTA failure. Only one (3%) patient required major amputation. Neither cardiovascular risk factors, treatment indication, location of the diseased arterial segment, nor quality of distal runoff vessels predicted the need for secondary PTA or surgical procedures. PTA of the proximal arteries in young patients with PLEA is an effective primary revascularization technique with results comparable to those of conventional operative revascularization procedures.

Impaired homocysteine metabolism: a risk factor in young adults with atherosclerotic arterial occlusive disease of the leg

To assess the prevalence of impaired homocysteine metabolism in young adults with arterial occlusive disease, 80 consecutive patients under 45 years old were screened. Various laboratory blood investigations and a standardized methionine loading test were performed. In the first 52 patients plasma levels of free homocysteine were determined; thereafter the levels of total homocysteine (a more sensitive measure of impaired homocysteine metabolism) were measured. The methionine loading test was abnormal in 15 patients (19 per cent) who did not differ from the other 65 with respect to prevalence of other risk factors, clinical characteristics, and electrocardiographic and angiographic findings. Blood levels of glucose, vitamins B6 and B12, folate, protein C and protein S, fibrinogen and low-density lipoprotein cholesterol did not differ significantly between the two groups. The prevalence of impaired homocysteine metabolism in young patients with arterial occlusive disease is greater than the 1-2 per cent found in the normal population.

Hypercoagulable states in patients with leg ischaemia

Hypercoagulable states are found in up to 10 per cent of patients with a history of unexplained venous thrombosis. To investigate the prevalence in arterial thrombosis, thrombophilia screening was performed on 124 patients who had previously undergone lower-limb revascularization, 45 claudicants and 27 controls. Of the patients who had undergone revascularization 40 per cent had a hypercoagulation abnormality (low levels of protein C, protein S and antithrombin III or presence of the lupus anticoagulant) in comparison with 27 per cent of claudicants and 11 per cent of controls (P < 0.01). Furthermore, patients who had suffered reocclusion after revascularization were significantly more likely to have a hypercoagulation abnormality than those who had not (P < 0.05), even if the occlusion had occurred more than 6 months previously. Lupus anticoagulant was the abnormality most frequently detected and, like low protein C levels, was found only in patients with peripheral vascular disease. It appears that hypercoagulable states are common in patients with arterial disease and may predispose to failure of revascularization.

Lower extremity ischemia in adults younger than forty years of age: a community-wide survey of premature atherosclerotic arterial disease

A retrospective community-wide survey identified 109 patients younger than 40 years of age with lower extremity ischemia: 72 men and 37 women, mean age 36 years (range 25 to 40 years), black-to-white ratio-1:1. Initially, 66 patients had claudication and 43 had severe ischemia. Cardiovascular risk factors were smoking (85%), hypertension (47%), coronary artery disease (30%), hyperlipidemia (27%), diabetes (25%), and visceral arteriopathy (17%). Unique risk factors included hypercoagulability (15%) and clinical arterial hypoplasia (15%). Twenty-three (21%) patients were treated medically; 74 (68%) underwent primary revascularization and 12 (11%) primary major limb amputation. Forty-six (53%) patients required secondary procedures, of which 34 (74%) were performed within 1 year of primary intervention. A total of 29 (27%) patients ultimately required amputation (10 bilateral). Women had higher prevalence of diabetes (p < 0.01), arterial hypoplasia (p < 0.05), and tendency for more severe ischemia (p = 0.11). No racial differences in severity of symptoms or outcome of treatment were found. By multiple logistic regression analysis, typical cardiovascular risk factors did not predict severity of symptoms, need for surgical treatment, or outcome. However, diabetes was associated with tissue loss (p < 0.05) and primary amputation (p < 0.001). Further, adjusted odds ratios indicate that arterial hypoplasia had a protective effect on distal vasculature (p < 0.05) and predicting need for revascularization (p < 0.05), but not on treatment failure. Hypercoagulability had the highest predictive value for presence of severe ischemia (p < 0.05), need for primary amputation (p < 0.01), and early failure of surgical treatment (p < 0.05).

Lipoprotein [Lp(a)] and peripheral vascular disease

Lipoprotein(a) [Lp(a)], which combines structural elements of the lipid and fibrinolytic systems, is a major independent risk factor for the development of coronary heart disease. Eighty-four consecutive patients with peripheral vascular disease (of whom 42 had concomitant ischaemic heart disease) and 43 healthy controls were enrolled in a case-control study. We found that the mean Lp(a) concentration in male patients with peripheral vascular disease (PVD) was almost threefold higher than that of controls, while in female patients the Lp(a) concentration was more than twice that of controls. This marked difference was borne out in patients with and without concomitant ischaemic heart disease (IHD). A multivariate logistic regression analysis indicated that Lp(a) is independently associated with PVD when adjusted for age and sex (odds ratio per 100 mg l-1 increase in Lp(a) = 1.35; P < 0.01). A similar association is observed for patients with concomitant IHD (odds ratio per 100 mg l-1 increase in Lp(a) = 1.65; P < 0.01).

Disorders of the hemostatic system and the risk of the development of thrombotic and cardiovascular diseases: limitations of laboratory diagnosis

The relationship between hemostatic abnormalities and thrombotic and cardiovascular diseases is summarized. All known congenital and acquired abnormalities in the biochemistry of hemostasis are related to thrombotic and cardiovascular diseases in the way that would be expected on the basis of theories about the role of balances between coagulation and fibrinolysis and between activating and inhibiting factors. Notwithstanding the consistency between theory and observed abnormalities, a causal relationship between biochemical abnormality and clinical symptoms has been proved only in a limited number of situations, and it is possible that certain abnormalities only (or also) mark pathologic events. The limitations of laboratory diagnosis of hemostatic disorders in relation to hemostasis as a local process are discussed. It is proposed that more attention be paid to methods of evaluating the local aspects, for example, methods that assess reaction products in the circulation and that can provide an averaged message of the local phenomena. In addition, such methods can provide information about the dynamic balances in the hemostatic system, whereas historically more attention has been paid to the static balances in the potential of hemostatic processes.