Surgical infrainguinal revascularization for peripheral arterial disease: factors affecting patency rate.

BACKGROUND: Peripheral arterial disease is a source of morbidity and mortality. Surgical vascular reconstruction is a treatment option but probability of failure and complications are important concerns. In this study, we evaluated outcome of surgical infrainguinal reconstruction and factors affecting graft patency for a period of one year.
METHODS: In this cohort study, 85 consecutive patients with chronic ischemia who underwent lower extremity surgical vascular reconstruction (including 52 femoropopliteal and 25 femorofemoral bypass) from March 2007 to Feb 2009 were recruited. Graft patency was evaluated before discharge from hospital and one year after the surgical operation using duplex ultrasonography. Association between possible risk factors and graft patency were evaluated.
RESULTS: In general, 71% (37 patients) of femoropopliteal and 52% (13 patients) of femorofemoral reconstructions were patent during the follow up period. Diabetes mellitus, hypertension, smoking, opium use and ischemic heart disease were significantly associated with decreased rate of patency (p<0.05).
CONCLUSION: Assessing risk factors that predict perioperative mortality and graft patency is essential for selecting patients that would benefit from surgery. Omitting surgical reconstruction and endovascular intervention may be preferable especially when multiple risk factors are present or in the absence of critical limb ischemia.

Introduction

Peripheral arterial disease (PAD) is a worldwide problem that has significant impact on quality of life and can also lead to mortality (1). As a result of the increased life expectancy and increased elderly population, the prevalence of PAD is growing (2). Patients with PAD may be asymptomatic, or they may present with intermittent claudication or chronic critical limb ischemia. The management of patients with PAD is complex and includes pharmacological therapy and/or surgery (3).

Surgical reconstruction can be an effective treatment that improves quality of life in case of claudication and save the limb in severe ischemia (4). However, since PAD is encountered usually in elderly patients with comorbidities, post-operative complications are major concerns (2,5). Besides, failure of revascularization and graft patency are seen in a proportion of patients; advent of endovascular intervention has provided alternate method of PAD management (6,7). This necessitates careful patient selection to achieve most beneficial result from surgical revascularization and avoid potential morbidity and complications. This study reviews experience of a referral center in infrainguinal surgical bypass and surveys patency rate and risk factors associated with failing in achievement of a durable vascular reconstruction.

Methods

Data

In this analytic prospective cohort study, 85 consecutive patients with chronic ischemia who underwent lower extremity surgical vascular reconstruction (including 52 femoropopliteal bypass and 25 femorofemoral bypass) were recruited. This study was done in a two year period from March 2007 to Feb 2009 at Imam Hospital affiliated to Tehran University of Medical Sciences. In addition to demographic data, patients’ comorbidities and risk factors including ischemic heart disease, diabetes mellitus, hypertension, hyperlipidemia, history of preoperative and post-operative smoking and opium use were also obtained. Patency of patients’ grafts were evaluated before discharge from hospital and one year after the operation using duplex ultrasonography. Statistical association between possible risk factors and graft patency were analyzed.

Statistical Analysis

Data were analyzed using SPSS version 18. Relation between patients’ characteristics and one year patency was evaluated using independent-sample t-test, Mann-Whitney, Fisher’s exact test, and Chi-Square tests. P-values of less than 0.05 were considered as significant.

Results

A total of 85 patients underwent infrainguinal surgical reconstruction during the study period. Eight patients did not adhere to follow up. Seventy seven patients were evaluated including 52 with femoropopliteal and 25 with femorofemoral vascular reconstruction. In all cases except for one femoropopliteal patient, saphenous vein grafts were used and in all femorofemoral patient synthetic graft was used.

The mean±SD age of the patients was 61.1±10.8 year (range: 39-89 year). Fifty three patients (67.9%) were male and 24 patients (32.1%) were female. The mean±SDcreatinine level was 0.99 ± 0.24 mg/dl (range: 0.5-1.6), and mean±SD cardiac ejection fraction (EF) was 45.2 ± 6.8 percent (range: 25-55). Male to female ratio among those who underwent femoropopliteal and femurofemural grafts were 2.5 to 1 and 1 to 1, respectively. Patient’s characteristics and the analyzed correlation between preoperative risk factors and one year patency have been depicted in Table 1.

Table 1

Patient’s characteristics and relation between them and one year reconstruction patency

Patient variable	N (%)	Patency In presence of variable (%)	Patency in absence of variable (%)	p
Diabetes mellitus	39(50)	36.5%	63.5%	0.001
Hypertension	28(36)	27%	73%	0.010
Smoking	35(45)	34.6%	65%	0.010
Opium use	32(41)	32%	67%	0.030
Ischemic heart disease	52(67)	53%	81%	0.010

Three patients (3.8%) died in post-operative period due to myocardial infarction. The mean±SD EF was 45.2 ± 6.8 percent in alive and 32.8 ± 6.4 percent in dead patients (p=0.001). Thirty seven patients among those who underwent femoropopliteal graft (71%) and 13 patients among those who underwent femorofemoral graft (52%) showed a one-year complete vascular patency (p=0.003). Among those with failed reconstruction, two (3.8%) patients in the femoropopliteal group and 3 (12%) patients in the femorofemoral group underwent amputation and other patients with failed reconstructions were managed medically. Age, sex and creatinine level were not statistically different between those with and without vascular patency (p<0.05). The mean±SD EF was 46.2 ± 7.4 percent in patent and 43.07 ± 4.9 percent in non-patent group that showed a significant difference (p=0.049). Hypertriglyceridemia was not related to the patency (p> 0.05). Patients with claudication, rest pain and ischemic ulcers had not different patency rates; but diabetes mellitus, ischemic heart disease, hypertension, history of preoperative or postoperative smoking, and opium use were associated with failure of one year vascular patency.

Discussion

Peripheral arterial occlusive disease is a major health problem and one of the most challenging vascular problems facing vascular surgeons. The complexity of the disease has been magnified by its association with other medical comorbidities such as cardiovascular and cerebrovascular disease. Therefore, risk factor modification seems to be essential to improve long-term survival of these patients (3). This study was performed to demonstrate the success and patency rate of infrainguinal vascular reconstruction for peripheral vascular disease and related factors affecting this patency. Generally, we found that 71% of femoropopliteal grafts and 52% of femorofemoral grafts had at least one year of patency. Similar results for femoropopliteal bypasses have been reported in other studies (8,9).

Goodney et al surveyed results of 2036 bypass procedures and reported a one year patency of 79% in patients suffering from claudication and 73% in patient with critical limb ischemia (9). In our study, patency rate was not statistically different in patients with critical ischemia compared to patients with claudication. Some studies have reported a decreased patency rate in older patients. This difference might be due the older mean age of patients in those studies comparing to ours. A cut off age of around 65-75 have been shown as a risk factor for patency failure (7,8). We found no relation between advanced age and patency rate that is consistent with some other reports (9,10).

Opium use was associated with lower rate of patency in our patients. Association of opium addiction with increased post-operative complications has been investigated and yielded different results (11-13).Adverse effects of opium on cardiovascular system in experimental and clinical settings has been shown (14-16). It may be reasonable to consider opium addiction as a risk factor affecting results of surgical reconstruction. It is particularly true when considering that opium addicts may have less compliance to treatment and follow up.

Diabetes mellitus, hypertension, ischemic heart disease and smoking was associated with decreased patency as are reported in other studies (17,18).Diabetes has been shown to increase risk of PAD, but the effectiveness of tight glycemic control with regard to halting the progression of PAD, relieving symptoms of claudication, or increasing amputation-free survival is unclear (3,4). Hypertension should be treated according to the recommendations of the Eighth Joint National Committee (19). While some controversy exists regarding the effect of smoking cessation on regression of symptoms of claudication, the effects of smoking on progression of symptoms, increased risk of amputation, and failure of surgical therapy have been studies. Therefore, all patients with PAD should be advised to stop smoking (3,20).

While endovascular treatments have appealing advantage of lower morbidity and mortality, bypass surgery still has better long term outcome for femoropopliteal lesions with reported patency rate of up to 70% at 5 years (4). Lower extremity endovascular interventions may also result in some complications such as those related to puncture site, intervention site, distal vessel, and also systemic complications (21).The use of stent grafts has been studied for treatment of long segment femoropopliteal occlusive disease as well. Similar long-term patency has been reported when compared to conventional femoral-popliteal bypass using synthetic conduit (22,23). Nevertheless, further studies are required to prove long-term effect and cost-effective benefit of these studies. Mortality rate of surgical bypass should be considered as well. In our study early mortality rate (within 30 days after surgery) was 3.8%. Feinglas et al, in their study of 28128 patients who underwent lower extremity surgical bypass reported 30 mortality of 4.8%. They also showed that 31.4% of patients were alive 5 years after their initial operation without major amputation or subsequent bypass or revision procedures (24).

Conclusion

Assessing risk factors that predict perioperative mortality and graft patency is essential for selecting patients that would benefit from surgery. Presence of such factors would suggest increased probability of graft occlusion and help surgeons in selecting best candidates for surgery. Omitting surgical reconstruction and endovascular intervention may be preferable especially when multiple risk factors are present or in the absence of critical limb ischemia.