The incidence of peripheral arterial disease (PAD), mainly atherosclerotic occlusive disease (ASO), is increasing year by year and has become one of the most important health hazards. The incidence of PAD is closely related to age, and according to the 1999-2000 population survey, the prevalence of PAD is 4% in people aged ≥40 years, but increases to 15% in people aged ≥70 years.
The early stage of the disease may show intermittent claudication of the lower extremities, and the progressive stage may show resting pain, ulceration or gangrene, i.e., severe limb ischemia (CLI).
Patients with CLI combined with other systemic diseases such as cardiac and cerebrovascular diseases have a 1-year mortality rate of 20% and a 5-year mortality rate of 50%. The development of endoluminal vascular technology and the continuous breakthroughs in adjuvant devices have greatly expanded the scope of application and enhanced the efficacy of traditional open surgical treatment, interventional treatment, or hybrid surgery combining surgery and interventional treatment for PAD. The following is a discussion of the current status of surgical and interventional treatment of lower extremity PAD.
1.Open surgery
For a long time, open surgery (OR) for patients with good surgical tolerance and indications for surgery has been the main treatment for lower extremity PAD. Depending on the lesion site and degree, thrombus endothelial debridement, patch angioplasty, inter-arterial placement or bypass diversion and anatomical external arterial diversion can be used, among which autologous materials can be selected from saphenous vein, cephalic brachial vein, radial artery internal iliac artery, and artificial materials including polyester (dacron) and expanded PTFE, ePTFRE, etc.
For OR, the evaluation includes intraoperative and postoperative bleeding, complications (departmental, procedure-related and graft material-related), mortality, postoperative clinical symptom profile (Fontail and Rutherford grading), ankle-brachial index (ABI) changes, anastomotic restenosis, reoperation rate, graft passage and amputation rate.OR for elderly and surgically high-risk patients, their perioperative OR has a relatively high perioperative mortality and complication rate for elderly and surgically high-risk patients.
For iliac artery lesions, OR includes abdominal aorta-iliac artery bypass diversion and anatomic external femoral-suprapubic crossover diversion. The former has a 5-year patency rate of up to 85% and a 5% perioperative mortality rate; the latter has a slightly lower patency rate than abdominal aorta-bilateral iliac artery and abdominal aorta-unilateral iliac artery bypass diversion, but the operative mortality rate is <5% and can be applied to elective cases. The 7-year patency rate of common femoral artery and femoral artery bifurcation site endarterectomy can be as high as 96%, but complications such as wound infection, lymphatic fistula and hematoma can occur, and their incidence ranges from 0 to 17.7%.
Autologous veins have been the material of choice for arterial reconstruction of the lower extremity, with a 5-year patency rate of up to 75% for suprapatellar artery reconstruction and a 5-year postoperative amputation rate of <20% for CLI patients; Slim et al. suggested that autologous veins >2 mm in diameter could also be used as graft material for CLI patients. but less effective in infrapopliteal artery reconstruction. Given the length and caliber requirements for use as a vascular graft material, artificial vessels are the only option for patients with insufficient autologous vessels.
For the addition of a small segment of autologous venous collar (veincollar) to the distal anastomosis of PTFE to improve the outflow tract patency in the long term, a Swedish multicenter, prospective, randomized controlled study of 352 patients with 202 femoral-subknee? artery bypass, of which 1155 had an autologous vein collar; another 150 had femoral-calf artery bypass, of which 72 had an autologous vein collar, and the results of the study were found to have better vascular patency and limb salvage rates in the veincollar group.
To increase long-term patency and limb salvage, especially in cases where the distal anastomosis is located in the infrapopliteal artery, Gore, Inc. has improved the heparin-conjugated ePTFE, a bioactive material, to reduce early thrombosis and late neointima by combining the anti-inflammatory effects of heparin on its surface to increase the patency of the artificial vessel. Currently Pulli et al. used PropatenGore-Tex bioactive vessels (W, L. Gore & AssociatesInc, Flagstaff, Ariz.) to treat 425 patients with CLI between 2002 and 2008, 101 with superior knee artery reconstruction and 324 with inferior knee.
For the distal anastomosis of the infrapopliteal artery reconstruction, 238 cases were located in the ? artery, 38 in the tibiofibular trunk, 20 in the anterior tibial artery, 23 in the posterior tibial artery, and 5 in the peroneal artery. The perioperative mortality rate was 3.1%, the early patency rate was 92.5%, and the amputation rate was 4.2%. 420 patients were followed up for a mean of 25.5 months, and the expected cumulative 3-year primary patency and secondary patency rates were 61% and 70%, respectively, and the amputation rate was 17%.
For high-risk factors for amputation, univariate analysis indicated ischemic ulceration or necrosis of the limb, poor outflow tract, reoperation, and use of antiplatelet aggregation drugs rather than anticoagulants, whereas multivariate analysis indicated reoperation, poor outflow tract, and preoperative clinical presentation. Therefore, the authors concluded that PropatenGore-Tex bioactive vessels could be used as an alternative material when autologous vessels are insufficient.
It is worth our attention that although the patency rate is one of the indicators for judging the efficacy after revascularization, patency does not mean limb salvage. As early as 1990, Dietzek et al. retrospectively studied 987 patients after subinguinal ligament revascularization, 7.6% of the grafts were patent but still required amputation; Carseten et al. reported this rate to be 9%; Simonss et al. prospectively studied 1012 patients and noted that for CLI patients, this rate was 10%. This phenomenon may be related to diabetes, extensive gangrene and infection of the foot, or combined with chronic renal insufficiency, or preoperative hemodialysis or the need for support to stand, for such patients, we should pay attention to preoperative.
2.Interventional treatment
Compared with OR which needs to be performed under semi-body or general anesthesia, more surgical trauma than intraoperative bleeding and relatively long operation time, minimally invasive intracavitary intervention has now taken an important place in the treatment of PAD. Interventional treatment is suitable for elderly high-risk patients, those with poor surgical tolerance, and those without suitable autologous vessels as vascular graft material. From the TASC classification (TASC), Class A is best for interventional treatment, Class B is better than OR, Class C is better than OR, and Class D is appropriate for OR. The evaluation of interventional treatment is similar to OR, but with the addition of intraoperative and postoperative complications related to materials including various types of catheters, guidewires and stents such as catheter and guidewire fracture, entry into the entrapment, stent displacement and fracture, and complications related to interventional treatment. and complications related to interventional treatment such as puncture site hematoma, pseudoaneurysm formation, and arterial thrombosis at the treatment site.
The rapid development of interventional materials and techniques in recent years has made it possible to intervene in some lesions that were not considered suitable for interventional treatment in the early stages, such as TASC C and D lesions. From the point of view of medical development and the state of clinical practice, the TASC classification has shown its limitations since its introduction, although some modifications have been made. In terms of inpatient admissions in the United States between 2001 and 2007, surgical treatment of lower extremity PAD increased by 18% per year and interventional treatment increased by 78% per year, while OR decreased by 20% per year.
In addition to developments in materials, interventional techniques continue to be innovative. In addition to the widely performed SIA technique, the trans-lateral branch artery puncture cannulation derived from coronary angioplasty for the treatment of the calf artery, and bi-directional cannulation through the femoral and calf arteries respectively for the treatment of ? and the occluded segment of the calf artery, have been successfully applied to selective refractory lesions.
In general, the primary patency rate after intervention in patients in TASC categories C and D is significantly lower than that in patients in categories A and B, especially in category D, but amputation can still be effectively avoided because of the higher secondary patency rate in the latter; hypertension and hyperlipidemia can significantly affect the primary and secondary patency rates, and in category D patients, age is also an important factor affecting the primary patency rate.
Among patients in categories C and D, the improvement of clinical symptoms and blood supply and the reduction of amputation rate after surgery were considered significantly better in patients with intermittent claudication than in patients with CLI. Studies in the United States have also shown a 21% reduction in above-knee amputation rates and a 5% reduction in foot and toe amputation rates in patients with PAD as a result of the intervention.
For iliac artery lesions, the randomized controlled Dutch Iliac Artery Stenting Clinical Trial (DIST) noted that 43% of patients randomized to the percutaneous balloon dilation (PTA) group
Patients required stenting because of suboptimal PTA alone, with 2-year postoperative patency rates of 71% and 70% in the stent and PTA groups, respectively; another multicenter, prospective randomized controlled clinical trial, currently just completed and not yet published, suggested that iliac artery stenting significantly reduced postoperative complications compared with PTA treatment alone, but stenting did not contribute to patency rates.
In addition, Pulli et al. performed PTA and stenting in 223 iliac artery lesions, including 109 occlusive lesions and 114 stenotic lesions, with a technical success rate of 99% in both groups, perioperative complication rates of 9% and 3.5%, respectively, and early patency rates of 97.3% and 98.7%, respectively; primary patency rates at 5 years were 82.4% and 77.7%, respectively. The expected secondary patency rates were 93.1% and 92.8%, respectively, and the cumulative reoperation rates at 5 years were 2.5% and 12.5%, respectively, with no statistically significant differences between the two groups.
Meanwhile, SIA treatment combined with stenting for long-segment occlusive iliac artery lesions (>5 cm) was an effective treatment with a technical success rate of 99%, procedure-related complications of 4.8%, and primary patency rates of 98% and 91% at 1 and 2 years after the procedure, respectively. The technical success rate of common femoral artery intervention is 91% to 100%.
The rate of perioperative complications was <9.5%. Baumann et al. retrospectively studied 104 ischemic limbs with common femoral artery occlusion, 19% of which were CLI limbs, and the technical success rate was 98%, with a significantly higher ABI in both postoperative periods. the rates of sustained clinical improvement at 1 and 2 years postoperatively were 40% and 0 in patients with CLI and 68% and 52% in patients with interstitial claudication, and the amputation rates at 2 years postoperatively were The rates of amputation at 2 years after surgery were 6% and 0, respectively; the presence of ischemic ulcers in the limb, combined femoral-N?artery occlusion and diabetes mellitus were all high risk factors for postoperative outcome.
The safety of the procedure has been demonstrated, and its vascular patency and amputation rates are encouraging.
Similar to OR, arterial patency at the intervention site does not imply limb salvage. Khan et al. reported 236 interventional CLI limbs, and of 24 amputated patients, 19 (80%) had patency of the treated artery, and multifactorial analysis suggested that diabetes, limb gangrene, and infrapopliteal artery intervention were high-risk factors for amputation.
3. Comparison of OR and interventional treatment
The well-known prospective, multicenter, randomized controlled clinical trial BASIL studied 452 patients with CLI and showed that PTA and arterial bypass diversion had equal effects on their survival without postoperative amputation events. At 5 years of follow-up, 56% of patients died and 7% of surviving patients underwent amputation, with no significant difference in survival and amputation rates between the two groups; patients who survived more than 2 years after surgery in the OR group had a significantly higher survival rate than in the PTA group, and patients in the OR group had an increased life expectancy of 7 months compared with the PTA group, which may be related to the high reoperation rate in the PTA group and the close follow-up and long-lasting efficacy in the OR group.
Meanwhile, the difference in cost gradually disappeared as the follow-up time of the two groups increased, and the improvement in quality of life was equal in both groups from 3 months after surgery and continued until 3 years after surgery.
A retrospective study of a large sample of 4119 hospitalized cases of aorto-iliac artery lesions showed a lower rate of postoperative complications and fewer days in the hospital compared with OR; mortality was slightly higher in the OR group (2.5%) than in the intervention group (1.8%), but there was no significant difference between the two groups; age >65 years, concurrent comorbidities and OR were important causes of postoperative complications.
In 858 cases of femoral-? arteriopathy CLI patients, 517 with PTA and 341 with OR, the study showed 5-year amputation rates of 22% and 8%, survival rates of 49% and 57%, and reoperation rates of 14% and 6%, respectively; after using propensityscoreanalysis, the amputation rate (26%) and reoperation rate in the PTA group ( The authors concluded that the long-term efficacy of PTA is not as good as that of OR in this group of patients, which may be related to factors such as the preference of interventional treatment for elderly high-risk patients, poor surgical tolerance, and the absence of suitable autologous vessels as vascular graft material.
4.Summary
There are no clear criteria for choosing PAD or OR treatment. Generally speaking, interventional therapy is the preferred method for limb salvage in elderly patients, patients with high surgical risk, those who cannot use autologous vessels as graft material, and those with poor outflow tract. Thanks to the development of material science and interventional techniques, the treatment principles based on the TASC classification have been constantly updated, and the original view of class C and D lesions, which were considered inappropriate for interventional treatment, has changed.
For multiplanar, multisegmental arterial lesions, OR combined with interventional hybrid procedures can be effective in saving limbs and improving vascular patency in selective cases, especially in TASCC and D categories.
Diabetes mellitus is an important factor affecting postoperative vascular patency and amputation in both OR and intervention, and old age, renal failure requiring hemodialysis and poor outflow tract are also important causes of procedure failure. Although the interventional treatment is minimally invasive, the large amount of contrast agents makes the incidence of postoperative renal complications much higher. Meanwhile, maintenance of patency does not guarantee limb salvage; early treatment before disease progression to CLI or limb ulceration can reduce postoperative amputation rates and complication rates.
In addition to the postoperative efficacy assessment indexes mentioned in the above article, Finnvasc score and modified PreventIII score are also used as criteria for early, mid-term and long-term efficacy assessment after OR and interventional treatment in Europe and the United States, making the assessment more quantitative and precise. Preoperative comprehensive assessment of the patient’s systemic disease and arterial anatomy, individualized treatment plan, skillful technique, rational selection of materials, rational postoperative medication and close follow-up and early detection of lesions using imaging techniques will reduce intraoperative and postoperative mortality and complication rates and enhance long-term outcomes from a technical standpoint.