Infrainguinal arterial reconstruction for claudication: is it worth the risk? An analysis of 409 procedures

Open Surgical Therapy for Peripheral Artery Disease

PURPOSE OF REVIEW

The surgical management of symptomatic peripheral artery disease (PAD) has changed in the last few decades. Improvement in endovascular technology has resulted in more complex lesion once reserved for open surgery being addressed in an endovascular fashion. Even with these advances, there are lesions and patients that are better managed with an open surgical procedure. The aim of this review is to describe the most commonly performed open surgical procedures for PAD.

RECENT FINDINGS

The recently published Best Endovascular versus Best Surgical Therapy (BEST-CLI) trial was an international, prospective, randomized controlled trial that aimed to investigate which revascularization (endovascular vs. surgical bypass) approach was superior for limb salvage. The evidence supports an open surgical bypass as an initial approach. The advancements made in the surgical management of PAD have provided options for patients who were once deemed poor surgical candidates. The goal continues to be utilization of the best available tools to address patient disease. In this current era, it is important to be familiar with the open surgical therapies.

Quantifying the risk-adjusted hospital costs of postoperative complications after lower extremity bypass in patients with claudication

OBJECTIVE

Increasing evidence has shown that the risks associated with surgical revascularization for intermittent claudication outweigh the benefits. The aim of our study was to quantify the cost of care associated with perioperative complications after elective lower extremity bypass (LEB) in patients presenting with intermittent claudication.

METHODS

All patients undergoing first-time LEB for claudication in the Healthcare Database (2009-2015) were included. The primary outcome was in-hospital postoperative complications, including major adverse limb events (MALE), major adverse cardiac events (MACE), acute kidney injury, and wound complications. The overall crude hospital costs are reported, and a generalized linear model with log link and inverse Gaussian distribution was used to calculate the predicted hospital costs for specific complications.

RESULTS

Overall, 7154 patients had undergone elective LEB for claudication during the study period. The median age was 66 years (interquartile range, 59-73 years), 67.5% were male, and 75.3% were white. Two thirds of patients (61.2%) had Medicare insurance, followed by private insurance (26.9%), Medicaid (7.7%), and other insurance (4.2%). In-hospital complications occurred in 8.5% of patients, including acute kidney injury in 3.0%, MALE in 2.8%, wound complications in 2.3%, and MACE in 1.0%. The overall median crude hospital cost was $11,783 (interquartile range, $8911-$15,767) per patient. The incremental increase in cost associated with a postoperative complication was significant, ranging from $6183 (95% confidence interval, $4604-$7762) for MALE to $10,485 (95% confidence interval, $6529-$14,441) for MACE after risk adjustment.

CONCLUSIONS

Postoperative complications after elective LEB for claudication are not uncommon and increase the in-hospital costs by 46% to 78% depending on the complication. Surgical revascularization for claudication should be used sparingly in carefully selected patients.

Long-Term Results of Distal Bypass for Intermittent Claudication

BACKGROUND

Distal bypass (DB) is the optimal treatment for patients with critical limb ischemia (CLI). However, effectiveness of DB for patients with intermittent claudication (IC) remains uncertain. This study aimed to analyze long-term results of DB for IC patients (IC-DB) compared with those of DB for CLI patients (CLI-DB).

METHODS

Patients undergoing DB from January 2009 to July 2018 at a single institution were retrospectively reviewed. Operative details, primary and secondary patency, amputation free survival rate (AFS), and long-term exercise capacity using Barthel index were analyzed.

RESULTS

Out of 302 DB (245 patients), 49 IC-DB were performed in 43 patients: 38 males, mean age 70.3 ± 8.0 years, diabetes mellitus 51%, chronic renal failure with hemodialysis 7%. The Great saphenous vein was used in 47 limbs, the small saphenous vein in 1, and the arm vein in 1. These grafts were bypassed in a non-reversed fashion for 35 limbs, in an in-situ fashion in 9, and in a reversed fashion in 5. The mean operative time was 173 min. The mean follow-up was 25 ± 26 months. Primary and secondary patency of IC-DB was 79% and 94% at 1 year, 71% and 90% at 3 years, 65% and 90% at 5 years, which were significantly higher than those of CLI-DB (primary patency: P = .007, secondary patency: P = .025). AFS of IC-DB and CLI-DB was 100% and 77% at 1 year, 93% and 52% at 3 years, and 90% and 43% at 5 years (IC-DB vs. CLI-DB, p < .0001). Barthel index of IC-DB unchanged at discharge (median 100) and at the last visit (median 100), showing daily activity was maintained adequately.

CONCLUSIONS

DB could offer a promising approach for patients with IC because of durable graft patency, acceptable AFS, and maintenance of daily activity.

Results for primary bypass versus primary angioplasty/stent for intermittent claudication due to superficial femoral artery occlusive disease

BACKGROUND

Percutaneous transluminal angioplasty ± stent (PTA/S) and surgical bypass are both accepted treatments for claudication due to superficial femoral artery (SFA) occlusive disease. However, long-term results comparing these modalities for primary intervention in patients who have had no prior intervention have not been reported. We report our results with 3-year follow-up.

METHODS

We reviewed all lower extremity bypass procedures at Beth Israel Deaconess Medical Center from 2001 through 2009 and all PTA/S performed from 2005 through 2009 for claudication. We excluded all limb salvage procedures and included only those that were undergoing their first intervention for claudication due to SFA disease. We recorded patient demographics, comorbidities, perioperative medications, TASC classification, and runoff. Outcomes included complications, restenosis, symptom recurrence, reinterventions, major amputation, and mortality.

RESULTS

We identified 113 bypass grafts and 105 PTA/S of femoral-popliteal lesions without prior interventions. Bypasses were above the knee in 62% (45% vein) and below the knee in 38% (100% vein). Mean age was 63 (bypass) versus 69 (PTA/S; P < .01). Mean length of stay (LOS) was 3.9 versus 1.2 days (P < .01). Bypass grafts were used less for TASC A (17% vs 40%; P < .01) and more for TASC C (36% vs 11%; P < .01) and TASC D (13% vs 3%; P < .01) lesions. There were no differences in perioperative (2% vs 0%; not significant [NS]) or 3-year mortality (9% vs 8%; NS). Wound infection was higher with bypass (16% vs 0%; P < .01). None involved grafts. Bypass showed improved freedom from restenosis (73% vs 42% at 3 years; hazard ratio [HR], 0.4; 95% confidence interval [CI], .23-.71), symptom recurrence (70% and 36% at 3 years; HR, 0.37; 95% CI, .2-.56), and freedom from symptoms at last follow-up (83% vs 49%; HR, 0.18; 95% CI, .08-.40). There was no difference in freedom from reintervention (77% vs 66% at 3 years; NS). Multivariable analysis of all patients showed that restenosis was predicted by PTA/S (HR, 2.5; 95% CI, 1.4-4.4) and TASC D (HR, 3.7; 95% CI, 3.5-9) lesions. Recurrence of symptoms was similarly predicted by PTA/S (HR, 3.0; 95% CI, 1.8-5) and TASC D lesions (HR, 3.1; 95% CI, 1.4-7). Statin use postoperatively was predictive of patency (HR, 0.6; 95% CI, .35-.97) and freedom from recurrent symptoms (HR, 0.6; 95% CI, .36-.93).

CONCLUSIONS

Surgical bypass for the primary treatment of claudication showed improved freedom from restenosis and symptom relief despite treatment of more extensive disease, but was associated with increased LOS and wound infection. Statins improved freedom from restenosis and symptom recurrence overall.

A personal experience with the influence of diabetes and other factors on the outcome of infrainguinal bypass grafts for occlusive disease

OBJECTIVE

To investigate the influence of diabetes mellitus and other factors on the outcome of all infrainguinal bypass grafts performed for occlusive disease by a single surgeon at a tertiary referral center.

METHODS

The series includes 650 operations in 412 men and 238 women with median ages of 65 and 69 years, respectively. Critical ischemia was the indication for most procedures (n = 553, 85%), but 97 (15%) were done for claudication alone. Nearly half (n = 312, 48%) of the patients were diabetic, and 195 (30%) required insulin. All-autogenous vein was used for 389 grafts (60%). Synthetic or composite materials were employed for the remaining 261 grafts, 91 (35%) of which were entirely above the knee. Perioperative data were recorded contemporaneously and were supplemented by reviewing 558 of the 565 medical records and the Social Security Death Index. Survival, graft patency, and limb salvage were analyzed using logistic regression, Kaplan-Meier estimates and proportional hazards models.

RESULTS

Diabetics were more likely to have critical preoperative limb ischemia (P < .001), elevated serum creatinine (P = .003) or a history of previous coronary intervention (P = .015), lower extremity revascularization (P < .001) or minor amputations (P = .002). The operative mortality rate was 4.8%, and there were 81 graft occlusions (12%) and 49 major amputations (7.5%) during the index hospital admission. Patency was immediately restored in 46 of the 81 occluded grafts, but their secondary patency rates were only 62 +/- 16% at 1 year and 26 +/- 18% at 5 years. Insulin-dependent diabetes was associated with a higher incidence of early amputation (odds ratio, 2.6; 95% confidence interval [CI], 1.4-4.8; P = .004). Overall survival was 52 +/- 4% at 5 years and 25 +/- 5% at 10 years, and there were 175 late graft occlusions (27%), a total of 198 related reoperations and 107 late amputations (16%). The risks for further occlusion and/or major amputation after three or more graft revisions were 65% and 71%, respectively. Insulin-dependent diabetes also was associated with higher late mortality (hazard ratio [HR], 1.5; 95% CI, 1.2-1.8; P = .001) and amputation rates (HR, 1.5; 95% CI, 1.0-2.1; P = .026), but other independent variables like age, elevated serum creatinine, critical preoperative ischemia, synthetic conduits, and previous ipsilateral bypass had at least as much influence as diabetes on survival, graft failure or limb loss.

CONCLUSIONS

Diabetes was one of several factors influencing survival and limb preservation, but it did not adversely affect graft patency. The number of graft revisions was an important predictor of further occlusion or amputation.

Infrapopliteal Intervention for the Treatment of the Claudicant

As the associated risks of infrainguinal balloon angioplasty and stenting have fallen and the relative success rates have risen in recent years, the threshold for offering endovascular treatment to patients with claudication has significantly decreased. Patients once considered appropriate only for risk-factor modification, exercise therapy, and medical treatment are now increasingly being offered percutaneous revascularization as a primary treatment option. Similarly, occlusive disease of the tibial vessels, once thought to be the exclusive domain of operative bypass, is increasingly being treated percutaneously. Over this same period, results of operative infrainguinal arterial reconstruction have also considerably improved. In modern times, excellent outcomes following bypass grafting with autogenous vein to the tibial level have been demonstrated, with morbidity, mortality, and long-term patency equivalent to that of more proximal bypasses. Evidence supports the view that the anatomic level of the distal anastomosis is less critical to the long-term outcome of the procedure than factors such as operative indication and conduit quality. Within the context of this changing climate, it is an appropriate time to examine and potentially redefine the role of both endovascular and open surgical intervention for a population that has not traditionally been offered revascularization, patients with claudication secondary to infrageniculate occlusive disease.

Endoluminal Angioplasty of the Popliteal Artery. Review of 54 Consecutive Patients

AIM

To determine the results of endoluminal angioplasty for occlusive or stenotic lesions of the popliteal artery.

METHODS

Retrospective study of symptomatic patients having popliteal occlusive lesions treated by endoluminal balloon angioplasty. All patients underwent systematic preoperative and postoperative color duplex scan and preoperative angiography. The principal endpoints were primary and primary assisted patency.

RESULTS

Fifty-four percutaneous endoluminal angioplasties of the popliteal artery, including six procedures with stents, were performed in 50 patients. In all cases, the superficial femoral artery was patent and without significant stenosis. Primary patency for the entire cohort was 57.4+/-6.7% at 1 and 2 years. Primary assisted patency was 86.3+/-4.8% at 1 year, and 79.1+/-5.9% at 2 years. The results of angioplasty appeared to be better in patients with intermittent claudication when compared to patients with critical limb ischaemia, (p=0.0006). Angioplasty of single occlusive lesions had a better prognosis than that of multiple occlusive lesions (p=0.01). Results of angioplasty were better at the below-knee and median popliteal artery than at the femoro-popliteal junction or in the above-knee popliteal artery (p=0.03). Tibial run-off and isolated popliteal stenosis versus isolated popliteal thrombosis did not seem to affect primary patency rate.

CONCLUSION

Results of angioplasty of the popliteal artery are acceptable for claudicants, especially those with TASC-A lesions and those with lesions in the distal two thirds of the popliteal artery.

Cardiovascular tissue engineering: state of the art

In patients requiring coronary or peripheral vascular bypass procedures, autogenous arterial or vein grafts remain as the conduit of choice even in the case of redo patients. It is in this class of redo patients that often natural tissue of suitable quality becomes unavailable; so that prosthetic material is then used. Prosthetic grafts are liable to fail due to graft occlusion caused by surface thrombogenicity and lack of elasticity. To prevent this, seeding of the graft lumen with endothelial cells has been undertaken and recent clinical studies have evidenced patency rates approaching reasonable vein grafts. Recent advances have also looked at developing a completely artificial biological graft engineered from the patient's cells with surface and viscoelastic properties similar to autogenous vessels. This review encompasses both endothelialisation of grafts and the construction of biological cardiovascular conduits.

Engineering of bypass conduits to improve patency

For patients with severe coronary artery and distal peripheral vascular disease not amenable to angioplasty and lacking sufficient autologous vessels there is a pressing need for improvements to current surgical bypass options. It has been decades since any real progress in bypass material has reached mainstream surgical practice. This review looks at possible remedies to this situation. Options considered are methods to reduce prosthetic graft thrombogenicity, including endothelial cell seeding and developments of new prosthetic materials. The promise of tissue-engineered blood vessels is examined with a specific look at how peptides can improve cell adhesion to scaffolds.

Long-term Outcome of Infrainguinal Percutaneous Transluminal Angioplasty

PURPOSE

To evaluate the long-term outcome of infrainguinal percutaneous transluminal angioplasty (PTA).

METHODS

Between 1991 and 1994, 77 patients (45 men; mean age 70 years, range 41-85) underwent infrainguinal PTA for occlusive disease. Patient records and angiographic examinations were reviewed to extract data to a patient register. A long-term (mean 9.3 years) follow-up examination of survivors was performed, including physical evaluation, walking impairment questionnaire (WIQ), and duplex ultrasound.

RESULTS

Cumulative primary and secondary patency rates, respectively, were 81% and 86% at 1 year, 65% and 73% at 5 years, and 12% and 17% at 10 years. Patency rates were better for patients with claudication than critical ischemia (p=0.02). Stenoses had better primary patency than occlusions (p=0.001), but there was no difference between stenoses <2 cm versus >/=2 cm. At long-term follow-up, patients with patent vessels (50%) had better ankle-brachial indices (p=0.01) and less pain in their calves (p=0.04) compared to patients with non-patent vessels, but there was no difference in walking capacity or quality of life. Generalized femoral artery disease (p=0.03) and diabetes mellitus (p=0.03) predicted poor survival.

CONCLUSIONS

Although the overall long-term patency of infrainguinal PTA is poor, the technique has a low morbidity and can be performed in selected patients with a reasonable long-term result.

Hemodynamic outcome of endovascular therapy for transatlantic intersociety consensus type B femoropopliteal arterial occlusive lesions

OBJECTIVE

Endovascular therapy for moderate femoropopliteal arterial occlusive disease remains controversial. This study reviewed our experience with endovascular therapy for TransAtlantic InterSociety Consensus (TASC) type B disease, which is defined as multiple stenoses less than 3 cm in diameter or a single stenosis or occlusion 3 to 5 cm in diameter. Stenosis-free patency was used as an objective end point to evaluate the hemodynamic outcome.

METHODS

A retrospective review was performed of all patients who had undergone endovascular treatment of TASC type B lesions between 1997 and 2002 at two referral centers. Balloon angioplasty was performed in all patients. Stenting was used selectively as an adjunct in patients with suboptimal angioplasty results. The treated sites were examined with duplex ultrasound scanning at 6-month to 12-month intervals. Stenosis-free patency was defined as the absence of stenosis greater than 50% diameter in the treated arterial segment with standard duplex criteria.

RESULTS

One hundred fifteen limbs in 98 patients were studied. The indication for treatment was claudication in 92 patients (80%) and ischemic rest pain or gangrene in the remaining patients (20%). Multiple lesions greater than 3 cm were treated in 89 limbs (77%), and a single lesion 3 to 5 cm long was treated in 26 limbs (23%). Balloon angioplasty alone was performed in 74 limbs (65%), and angioplasty and adjunctive stenting was performed in 41 limbs (35%). Endovascular therapy was technically successful in all but one patient (99%), and there was no perioperative mortality or limb loss. During follow-up recurrent stenosis was detected in 46 limbs (40%), and reocclusion occurred in 11 limbs (10%). Seven patients (6%) underwent surgical bypass after endovascular treatment failure. The aggregate 1-year stenosis-free patency rate at life table analysis was 55.1%. The 1-year stenosis-free patency for angioplasty alone was 58%, compared with 51% (NS) for angioplasty and adjunctive stenting. Univariate regression analysis failed to demonstrate a difference in stenosis-free patency for demographic variables, medical comorbidities, and anatomic characteristics (multiple vs single lesions; number of angioplasty procedures).

CONCLUSIONS

Endovascular therapy for TASC type B femoropopliteal lesions is safe and technically feasible. However, the length of time that a treated arterial segment remains free of stenosis is limited, and is not improved with adjunctive stenting. Recurrent stenosis, not occlusion, was the most common study end point, and few patients subsequently required surgical bypass. Predictors of outcome after endovascular therapy for TASC type B lesions were not identified in this study.

Optimal therapeutic approaches to femoropopliteal artery intervention

Superficial femoral artery disease presents a complex challenge for therapy. The extent of vascular involvement may vary from focal disease with symptoms of intermittent claudication to long total occlusions manifest as critical limb ischemia. Optimal therapy requires understanding the available options including exercise programs, pharmacologic medical therapy, surgery and interventional endovascular therapy. Rapidly advancing endovascular technology for enabling safe intervention in complex, long occlusive segments of the superficial femoral artery continues to emerge. New devices like the SafeCross wire, Excimer laser, Silverhawk Atherectomy catheter, Cryoplasty catheter and new generations of bare metal and drug-eluting nitinol stents are shifting the paradigm for therapy from surgical to more endovascular treatment even for the most complex disease presentation.

Outcome of revascularization procedures for peripheral arterial occlusive disease in Ontario between 1991 and 1998: a population-based study

PURPOSE

We describe the outcome of revascularization procedures used to treat peripheral arterial occlusive disease (PAOD), using population-based administrative data.

METHODS

A retrospective population-based cohort study utilizing administrative databases in Ontario, Canada, was conducted for fiscal years 1991 to 1998 to identify patients who underwent arterial bypass surgery and percutaneous transluminal angioplasty to treat PAOD. The Kaplan-Meier method was used to calculate cumulative survival rate and amputation-free survival rate. To analyze factors that affect these rates, multivariate analysis was performed with Cox proportional hazard models.

RESULTS

Over the study period 15,824 patients underwent bypass operations and 11,548 underwent angioplasty. For patients who underwent bypass surgery, 5-year cumulative survival rate was 61.5% and major amputation-free survival rate was 83.4%, compared with 69% and 92.2%, respectively, for patients who underwent angioplasty. Male sex, older age, diabetes, and heart disease were associated with increased risk for death after revascularization procedures. Increased risk for major amputation after revascularization procedures was associated with male sex, older age, and diabetes, whereas hypertension was linked to decreased risk.

CONCLUSION

To evaluate the long-term outcome of revascularization procedures for PAOD at the population level, survival and major amputation-free survival rates should be used, because they provide more clinically accepted estimates compared with the correlation between utilization rates for revascularization and amputation procedures, which have been used to describe outcome in previously published reports in the literature.

Infrainguinal revascularization because of claudication: total long-term outcome of endovascular and surgical treatment

OBJECTIVE

This study was undertaken to define total long-term outcome achievable with invasive treatment, ie, endovascular or surgical, in patients with claudication with infrainguinal lesions. Priority in primary treatment was given to percutaneous transluminal angioplasty.

METHODS

Data were analyzed for 233 consecutive patients with claudication in whom primary infrainguinal revascularization was performed in 304 limbs between 1989 and 1992. Patients were followed-up to May 2001 (mean, 81 months). Treatment included primary endovascular therapy when applicable (n = 272 limbs) or primary surgical treatment (n = 32; 10.5%). Type of further revascularization, if required, was selected on an individual basis for each patient. All procedures performed because of limb ischemia were recorded. Clinical outcome at the end of follow-up was compared with the preoperative condition. Cumulative primary, secondary, and total patency rates and development of chronic critical ischemia (CCI) were defined. Total patency reflects the ultimate achievable benefit of invasive treatment and refers to patency maintained at the primarily treated segment by means of any invasive (endovascular or surgical) therapy, including potential crossover to another treatment group.

RESULTS

A mean of 2 (median, 1) operations per limb were performed during follow-up. No additional operations were needed in 50.3% (n = 153) of limbs. Fontaine classification at the end of the study was better compared with the preoperative value (P <.0005). Crossover between endovascular and surgical treatment was recorded in 21.1% (n = 64) of limbs. At 5 years, primary, secondary, and total patency rates (plus or minus standard error of estimate [SEE]) were 27% +/- 3%, 45% +/- 3%, and 61% +/- 3%, respectively, and at 10 years these rates were 16% +/- 3%, 27% +/- 3%, and 41% +/- 3%. CCI developed in 37 limbs (12.2%), of which 15 (41%) had been treated with endovascular methods only. Type II diabetes and hypertension were statistically significant predictors of increased risk for CCI.

CONCLUSION

Combining endovascular and surgical methods when necessary improved total outcome of invasive infrainguinal treatment of claudication. Crossover between endovascular and surgical treatment was required in 21% of limbs over the long term.

Long-term outcome of patients with claudication after balloon angioplasty of the femoropopliteal arteries

PURPOSE

To report the long-term outcome of patients with lifestyle-limiting claudication after percutaneous transluminal angioplasty (PTA) of the femoropopliteal arteries.

MATERIALS AND METHODS

Between 1989 and 1992, 173 consecutive claudicant patients (mean age, 65 years; age range, 41-90 years) underwent PTA in 218 limbs; all interventions included femoral and/or popliteal arterial segments, and additional iliac (n = 27) and infrapopliteal (n = 11) arterial lesions were also treated. Patients were followed up for 7-10 years. Altogether, 37 (17%) limbs were classified as Fontaine class 2A, and 181 (83%) were class 2B. Average length of the primary lesion was 5.2 cm. Reinterventions were analyzed. Patency rates and patient survival were assessed by means of life table analysis. Cox-Mantel tests and Cox proportional hazards models were used to define associated independent determinants. Development of chronic critical ischemia (CCI) and its determinants was assessed by using the Pearson chi(2) test and multiple logistic regression analysis.

RESULTS

The primary and secondary patencies (+/- standard error of the estimate), respectively, were 46% +/- 3 and 63% +/- 3 at 1 year, 25% +/- 3 and 41% +/- 4 at 5 years, and 14% +/- 3 and 22% +/- 4 at 10 years. One-third (71 of 218) of the limbs required repeat interventions, including surgical revascularization in 35 limbs. Fourteen (6.4%) limbs developed CCI, resulting in a 0.8% incidence per year. In multivariate analysis, poor postinterventional peripheral runoff was an indicator of increased risk of CCI development (P =.03).

CONCLUSION

Although the long-term patency rates of PTA of the femoropopliteal arteries in claudicant patients were poor, the acceptable number of reinterventions and the low frequency of development of CCI imply the long-term benefits achievable with this treatment.

Femoropopliteal occlusive disease: diagnosis, indications for treatment, and results of interventional therapy

The relative role of percutaneous therapy versus bypass surgery for femoropopliteal occlusive disease (FPD) represents an area of great controversy in the field of vascular medicine. This controversy is complicated by the very dynamic therapeutic options that continue to be introduced, particularly on the endovascular side. The purpose of this review is to provide an overview of the current diagnostic modalities available to characterize the level and degree of vascular insufficiency and summarize the currently available endovascular therapeutic options with their clinical role and outcomes. Finally, future therapeutic advances that will soon be evaluated in clinical trials will be discussed.

Single nucleotide polymorphism (G994-->T) in the plasma platelet-activating factor-acetylhydrolase gene is associated with graft patency of femoropopliteal bypass

BACKGROUND

Plasma platelet-activating factor-acetylhydrolase (PAF-AH) is known to catalyze platelet-activating factor (PAF). The single nucleotide polymorphism (SNP) of plasma PAF-AH gene (G994 -->T in exon 9) is associated with a decreased level of plasma PAF-AH activity. This study analyzed the risk of the SNP on graft occlusion of femoropopliteal bypass in patients with atherosclerotic occlusive disease.

METHODS

We retrospectively assessed the patency of 50 above-knee femoropopliteal bypass grafting in 50 patients. Genomic DNA was analyzed for the mutant allele. Plasma PAF-AH activity was measured by radioimmunoassay.

RESULTS

The 10-year cumulative primary patency of the bypass was 78.5% in GG (normal genotype) and 50.0% in GT (heterozygous) or TT (homozygous deficient) (P <.05, Kaplan-Meier method). The relative risk of graft failure in GT or TT genotypes was 1.68 (P =.08, Cox proportional hazards model). PAF-AH activity (nmol/min/50 microL) was 1.92 +/- 0.82 in patients with patent grafts and 1.42 +/- 0.47 in those with occluded grafts (mean +/- standard deviation; P <.05, unpaired t test).

CONCLUSIONS

The SNP of plasma PAF-AH was associated with a decreased primary graft patency of above-knee femoropopliteal bypass. The risk of graft failure may increase when patients have the SNP. To confirm the independent risk of graft failure by the SNP, further study is necessary and prospective study should be performed.

Factors that predict site of outflow target artery anastomosis in infrainguinal revascularization

INTRODUCTION

Lower extremity revascularization is indicated for limb salvage and incapacitating leg claudication. Many risk factors (age, hypertension, diabetes, tobacco use, dyslipidemia, etc) have been associated with atherosclerosis and the development of peripheral arterial occlusive disease. However, whether these risk factors or the surgical indication (claudication or limb salvage) influences the extent and location of infrainguinal disease and hence the target artery (distal anastomosis) is unclear. This study examines the risk factors and indication for infrainguinal revascularization with respect to the type of bypass performed.

METHODS

Three hundred fifty-two infrainguinal revascularizations in 282 patients were retrospectively reviewed. Patient data, including demographics, cardiovascular risk factors, indications, types of revascularization, and perioperative complications and mortality, were collected. Data were analyzed with t test, chi(2) test, Fisher exact test, and multiple logistic regression.

RESULTS

The indication for surgical revascularization was claudication in 70 patients and limb salvage in 282. The likelihood of a popliteal anastomosis (above or below knee) versus a tibial or pedal anastomosis was decreased with increasing age (P =.002) and diabetes (P =.0001), and smoking increased the likelihood (P =.056). However, popliteal bypass also was strongly associated with claudication as the surgical indication (odds ratio [OR], 8.7; P =.0001), and 90% of the claudicant group had undergone popliteal anastomosis. Claudication and popliteal anastomosis were both linked to smoking; 97% of subjects who underwent operation for claudication were smokers compared with 75% of subjects who underwent tibial or pedal anastomosis for limb salvage (P =.001). After adjustment for indication, the likelihood of popliteal anastomosis was still decreased with diabetes (OR, 0.46; P =.002), and age had a borderline significant effect (P =.077). When the analysis was stratified by indication for surgery, the likelihood of popliteal bypass among patients who underwent operation for claudication was not influenced by age, diabetes, or smoking. However, within the subset of patients who underwent operation for limb salvage, the likelihood of any popliteal anastomosis was diminished by diabetes (OR, 0.50; P =.007), age (OR, 0.968 per year; P =.01), and chronic renal insufficiency (OR, 0.476; P =.04).

CONCLUSION

Infrainguinal peripheral arterial occlusive disease is not a homogenous disease entity. Claudication and limb salvage are associated with two distinct patterns of vascular disease with different risk factors. Patients who undergo operation for claudication are seen at an earlier age, have a high prevalence of smoking, and have proximal disease and a greater likelihood of a popliteal anastomosis. In contrast, patients for limb salvage are less likely to have a popliteal bypass, favoring a more distal target outflow anastomosis that is strongly influenced by advanced age, diabetes, and chronic renal insufficiency.

Improving the clinical patency of prosthetic vascular and coronary bypass grafts: the role of seeding and tissue engineering

In patients requiring coronary or peripheral vascular bypass procedures, autogenous vein is currently the conduit of choice. If this is unavailable, then a prosthetic material is used. Prosthetic graft is liable to fail due to occlusion of the graft. To prevent graft occlusion, seeding of the graft lumen with endothelial cells is undertaken. Recent advances have also looked at developing a completely artificial biological graft engineered from the patient's cells with properties similar to autogenous vessels. This review encompasses the developments in the two principal technologies used in developing hybrid coronary and peripheral vascular bypass grafts, that is, seeding and tissue engineering.

Comparison of the long-term results between surgical and conservative treatment in patients with intermittent claudication

BACKGROUND

The optional therapeutic strategy for patients with intermittent claudication remains controversial. In this study, we investigated the influence of surgical and conservative therapies on improving the quality of life in patients with intermittent claudication.

METHODS

We analyzed 427 patients who were admitted to our hospital with intermittent claudication in their legs during a 15-year period from January 1984 to December 1999. We separated them into 2 groups; 259 patients (362 legs) were treated surgically and 168 patients were treated conservatively.

RESULTS

At the suprainguinal and infrainguinal (above knee) region, the surgery group showed significantly better rate of improvement than did the conservative group, but in the infrainguinal (below knee) region, there was no significant difference between the 2 groups. The 3-year and 5-year patency rates for the arterial reconstruction of the suprainguinal and infrainguinal region was satisfactory, but that of the infrainguinal region was not very good even if an auto vein graft was used.

CONCLUSIONS

Aggressive surgical treatment is therefore recommended in patients whose distal anastomotic region is above the knee, because there are great benefits from surgical reconstruction. However, in patients whose distal anastomotic region is below the knee, conservative treatment might be just as effective as surgery.

The mechanical behavior of vascular grafts: a review

The development of intimal hyperplasia (IH) near the anastomosis of a vascular graft to artery is directly related to changes in the wall shear rate distribution. Mismatch in compliance and diameter at the end-to-end anastomosis of a compliant artery and rigid graft cause shear rate disturbances that may induce intimal hyperplasia and ultimately graft failure. The principal strategy being developed to prevent IH is based on the design and fabrication of compliant synthetic or innovative tissue-engineered grafts with viscoelastic properties that mirror those of the human artery. The goal of this review is to discuss how mechanical properties including compliance mismatch, diameter mismatch, Young's modulus and impedance phase angle affect graft failure due to intimal hyperplasia.

Effective hemodynamic diameter: an intrinsic property of vein grafts with predictive value for patency

INTRODUCTION

Conduit size and quality are major determinants of the long-term success of infrainguinal autologous vein grafting. However, accurate measurement of the internal diameter of vein grafts is difficult given their variable wall thickness and taper. The purpose of this study was to define the "effective" internal diameter of a vein graft according to its hemodynamic properties and to determine its significance for graft patency.

METHODS

Sixty infrainguinal bypass grafts performed on 57 patients were evaluated intraoperatively. Proximal and distal graft pressure and blood flow (Q(meas)) were measured with fluid-filled catheter transduction and ultrasonic transit-time flowimetry, respectively, after unclamping. Waveforms were recorded digitally at 200 Hz under baseline conditions and after stimulation with 60 mg of papaverine. According to Fourier transformation of the measured pressure gradient (DeltaP), the Womersley solution for fluid flow in a straight rigid tube was used to calculate theoretical flow waveforms (Q(calc)) for a range of graft diameters. The theoretical waveforms were then compared with the measured flow waveforms and the best-fit diameter chosen as the "effective hemodynamic diameter" (EHD). Only grafts in which the correlation coefficient of Q(calc) versus Q(meas) was more than 0.90 were accepted (n = 47) to assure validity of the hemodynamic model. After a mean follow-up of 12.5 months (range, 0.1-43.9 months), patency was determined by the life table method. Hemodynamic and clinical variables were tabulated, and their effect on patency determined the use of univariate and multivariate Cox regression.

RESULTS

Mean EHD was 4.1 +/- 0.1 mm with a range of 2.5 to 5.7 mm. Administration of papaverine caused profound changes in DeltaP (+78% +/- 17%) and Q(meas) (+71% +/- 12%) as expected, but had no effect on EHD (+0.05% +/- 0.1%). Univariate regression identified five variables associated with decreased secondary patency (P <.10): low EHD, conduit source other than the greater saphenous vein, high baseline DeltaP(mean), female sex, and redo operation. Of these, only low EHD was significant after multivariate analysis (P =.03). Patency of small diameter grafts (EHD < 3.6 mm; n = 11) was compared with patency of larger grafts (EHD > 3.6 mm; n = 36) to test a frequently espoused clinical guideline. Grafts with an EHD less than 3.6 mm exhibited significantly lower secondary patency compared with larger grafts (P =.0001). The positive and negative predictive values for an EHD less than 3.6 mm for secondary graft failure for grafts with at least 1 year follow-up were 86% and 88%, respectively.

CONCLUSION

An EHD is a unique parameter that quantifies conduit size and has a significant impact on vein graft patency. An EHD less than 3.6 mm portends graft failure.

The role of duplex scanning in decision making for patients with claudication

The aim of this study was to compare the accuracy of clinical decisions made for patients presenting with claudication on the basis of the ankle/brachial index (ABI) (at rest and postexercise) and duplex scanning with that made on the basis of angiograms. Fifty-six patients presenting with a history suggestive of claudication had the ABI taken at rest. Seven patients could not be exercised but their resting ABI was <0.8. Additional exercise testing was done in 49 patients; two were then excluded as there was no fall in the ABI. Thus, 54 patients were entered into the study and underwent color-flow duplex scans and angiography. A clinical decision was reached independently on the basis of the results of ABI and duplex scans as to a) conservative treatment, b) angioplasty, and c) surgery. This was compared to the decision reached on the basis of angiograms. The results show that the combined use of ABI (as a screening test) and duplex scanning can replace angiography for clinical decision making in nearly 80% of claudicants. Angiography will only be needed when duplex scans are inconclusive.