Atherosclerotic occlusive disease of the lower extremities (AOLE) is a major cause of ischemia in the lower extremities, leading to amputation and even life-threatening conditions in severe cases. According to the World Health Organization (WHO) in 2004, atherosclerosis has surpassed AIDS and tumors as the leading cause of death in the human race. Patients with lower extremity arterial stenosis and occlusion have varying degrees of cardiovascular and cerebrovascular lesions, and treatment is very risky. Traditional vascular bypass surgery is particularly risky because of its trauma, complications, and long hospitalization period. Interventional therapy, as a minimally invasive treatment, has great advantages as it avoids the higher risk of cardiovascular disease, has a short hospitalization period and can be easily repeated.
1.Data and methods
(1) General information
From March 2006 to September 2010, 128 patients with AOLE were admitted to our hospital, 78 males and 50 females, aged 54-90 years old, with an average age of 76.1 years. There were 91 cases of unilateral lesions and 37 cases of bilateral lesions. The duration of the disease was 5 days~7 years. There were 61 cases of combined diabetes mellitus, 72 cases of hypertension, 28 cases of coronary heart disease, and 18 cases of cerebral infarction. All patients had varying degrees of weakness, pain and decreased skin temperature in the affected limbs, including 101 cases of intermittent claudication, 57 cases of resting pain, 55 cases of heel and toe end skin ulcers; 35 cases of lesions in the iliac artery segment, 95 cases of lesions in the femoral artery segment, and 47 cases of lesions at the level of the carotid artery and below. tASC classification: 13 cases in category A, 85 cases in category B, 15 cases in category C, and 15 cases in category D. 128 patients 135 The affected limbs received interventional treatment; all cases were treated with postoperative anticoagulation, antiplatelet, improvement of microcirculation and rehabilitation.
(2) Treatment methods
All patients underwent preoperative CTA examination of both lower extremity arteries to obtain a preliminary understanding of the lower extremity arterial lesions and to decide on the surgical approach and method to be used. After systemic heparinization, a guidewire was used to enter the lesioned vessel and cross the lesion with the catheter, and the corresponding balloon was applied to dilate the lesioned vessel one by one according to the location and length of the lesion. In iliac artery lesions, a balloon-expanded stent is often placed first, and post-dilation with a research balloon is applied, or balloon dilation can be used directly. If there is acute thrombosis during the operation, urokinase thrombolysis can be injected directly through the catheter.
2.Results
(1) Immediate effect of interventional treatment
In 87 patients, 103 affected limbs received interventional treatment, with residual stenosis <30% as the technical success criterion. 2 of the affected limbs failed on the operating table because the guidewire could not pass due to severe vascular calcification, while the remaining 101 affected limbs were operated successfully, with a success rate of 98%.
Among them, 35 cases of iliac artery lesions, 6 cases were treated with simple balloon dilation, with balloon diameter of 7-8 mm and length of 4-250 px, and 29 cases were treated with stent placement, with stent diameter of 6-9 mm and length of 4-250 px, and all cases were treated with patency and residual stenosis of no more than 30%.
In 95 cases of femoral artery lesions, 45 cases were treated with simple balloon dilation, with balloon diameter of 4-6 mm and length of 4-300 px, and 50 cases were treated with balloon dilation + stent placement, with stent diameter of 6 mm and length of 8-300 px, and all cases were treated with patency and residual stenosis of no more than 30%.
Forty-seven cases were treated with artery and the following branches, all of them were treated with balloon dilation without stent placement, the diameter of the balloon used for artery was 4-6 mm, length 4-300 px, and the diameter of the balloon used for the three branches of the knee was 37.5 px~3 mm, length 10-300 px, 9 of them were failed because the artery and the following branches were completely occluded, the TASC classification was D, the guidewire could not open the occluded vessel, and the rest of the cases were operated. In the remaining cases, the surgery was successful, and at least one of the three branches of the infrapopliteal vessels was patent, among which 13 cases were directly dilated to the plantar artery arch.
(2) Clinical results
Immediately after the operation, the patients felt an increase in the skin temperature of the lower extremity, the distance of intermittent claudication was prolonged, and the resting pain was relieved, and the ulcer was completely healed in some cases at follow-up.
(3) Complications
There were three cases of hematoma formation at the puncture site, one of which underwent hematoma removal due to the size of the hematoma; there were two cases of acute thrombosis, and the blood flow was smooth after thrombolysis with urokinase injected through the catheter; there were 21 cases of arterial entrapment, and stents were placed to make the entrapment adhere to the wall, and none of them had vascular perforation or rupture.
3. Discussion
(1) Adaptation of interventional treatment
PTA is mainly applied to patients with stenosis or occlusion length within 375 px in TASC category A and B. There are 98 cases (76.6%) of category A and B in this group of 128 AOLE patients. With the continuous advancement of interventional techniques and materials, interventional treatments and indications are also evolving and can be applied to some class C patients, while the longest stenotic vessel treated in this group of cases was about 750px.
For patients in category D, due to diffuse lesions in the lower extremity arteries and lack of normal outflow channels, it is difficult to pass the guidewire through the stenosed and occluded vessels, making intervention difficult, and the outflow channels of the vessels are poor and the postoperative patency rate of the vessels is low. It was previously thought that deep femoral artery reconstruction and venous artery first surgery might be a better choice and intervention was rarely used. However, these patients are often combined with serious cardiovascular and cerebrovascular diseases and cannot receive larger surgical blows, so endovascular treatment as minimally invasive treatment is an option to save the limbs of patients. In our group, there were 15 patients of category D. Nine of them were found intraoperatively to have long segmental stenosis occlusion of the lower limb vessels, and the sub-knee vessels were barely visualized, but balloon dilation or stent placement could also be performed through the diseased vessels by slow rotational advancement of the guidewire catheter. We believe that these patients do not have complete vascular occlusion and may have newly formed thrombus in the center of the lesioned vessel, so the guidewire catheter can be passed through these potential gaps for therapeutic purposes. The immediate postoperative effect is fair, but the long-term effect remains to be further observed.
(2) Technical points.
A. Selection of catheter access
The choice of catheter access is the first step of interventional treatment, and is also the key to whether the balloon catheter can reach the diseased vessel for intraluminal treatment. There are mainly the following.
a. Retrograde puncture placement through the lateral femoral artery: suitable for stenosis or occlusion of the beginning segment of the superficial femoral artery on the affected side.
b. Parallel puncture placement via the affected common femoral artery: suitable for those without significant stenosis in the ipsilateral common femoral artery and the middle and upper end of the superficial femoral artery.
c. Transbrachial artery puncture placement: for patients with bilateral iliac artery stenosis or occlusion.
B. Choice of balloon
The diameter of the balloon used should not exceed the diameter of the normal vessel, and the length of the balloon should be greater than the length of the stenotic segment of the vessel. This reduces the number of dilatations and shortens the operation time on the one hand, and on the other hand, it causes less damage to the endothelium of the vessel and avoids extensive tearing of the intima, which obviously reduces the occurrence of surgical complications. For iliac artery lesions, we mostly use 7-8 mm diameter balloons, femoral artery lesions use 4-6 mm diameter balloons, and the three branches of the infrapopliteal vessels mostly use 1.5-3 mm diameter balloons. The length of the balloon should be decided according to the length of the specific arterial lesion, and the longest balloon can be used up to 300 px. With the continuous advancement of interventional materials, the emergence of small diameter (1.5~4mm) and long balloons (40~120mm) in the lower extremity has significantly improved the success rate of surgical interventions in the lower extremity arteries, especially in the infrapopliteal arteries. Long balloon angioplasty is less invasive, has faster postoperative recovery, is reproducible, and provides better treatment, and is now increasingly used in the clinical treatment of lower extremity arterial vascular occlusions.
However, the pressure and speed of dilatation should be appropriate. It should not be emphasized that balloon dilatation can completely restore the original diameter of the vessel, but partial dilatation can significantly improve the symptoms of lower limb ischemia, and even more attention should be paid when the local vascular calcification is obvious, because the compliance of the diseased vessel wall is poor, and too fast dilatation, too high pressure or excessive dilatation can easily cause thrombosis, vessel rupture or restenosis. In this group of cases, the dilatation pressure of iliac artery is mostly 8kpa, and the dilatation time is 1-2 minutes; the dilatation pressure of femoral artery is 8-10kpa, and the dilatation time is 2-3 minutes; the dilatation pressure of infrapopliteal vessels is 12kpa, and the dilatation time is 4 minutes; the balloon dilatation process should be performed under DSA fluoroscopy, and the pressure should be gradually increased to observe the morphological changes of the balloon. The same site should not be repeatedly dilated several times to avoid the formation of arterial entrapment.
C. Problems of stent placement
As PTA can lead to vascular entrapment tear and elastic retraction, while stenting overcomes the two main defects of PTA by squeezing the plaque and compressing the vessel wall, it is a new endoluminal treatment.
In our preliminary procedure iliac artery lesions were routinely stented intraoperatively because the long-term patency rate was significantly higher in the PTA plus stent group for iliac artery stenosis compared with PTA alone, and its long-term patency rate was comparable to the clinical patency rate in patients undergoing surgical revascularization.
The Atlantic Collaboration recommends that PTA alone be used only for lesions in the short segment of the superficial femoral artery, and the indications for stent selection are often limited to cases of failure after PTA. Therefore, stents are not routinely placed in femoral artery lesions and are only considered in cases of residual stenosis greater than 30% or arterial entrapment formation, but balloon angioplasty alone is often of limited efficacy in long-segment stenosis, and stenting is often required as an adjunct to treatment.
The artery is in the moving part of the knee joint, and the deformation of the artery with the bending of the knee joint is too great, which makes the stent easily fatigue and fracture, so the artery is not recommended to be stented. Since stent placement still has the problem of postoperative restenosis, there is a lack of sufficient data to support the placement of stents in the infrapopliteal artery, so stent placement in small infrapopliteal artery lesions should be taken with caution.
D. Surgical complications
There were three cases of hematoma formation at the puncture site, two cases of acute thrombosis, and 21 cases of arterial entrapment in this group, none of which had vascular perforation or rupture. Hematoma formation is often related to the intraoperative use of heparin anticoagulation and improper postoperative compression to stop bleeding. In this group of cases, we used point pressure on the arterial puncture site for 15-20 minutes, followed by gauze compression and elastic bandages for 6-8 hours, and the incidence of postoperative hematoma formation was relatively low. Intraoperative acute thrombosis is mostly associated with insufficient intraoperative anticoagulation, and once it occurs, urokinase thrombolysis can be injected directly from the catheter. The higher incidence of arterial coarctation is related to the patient’s advanced age and heavy degree of atherosclerosis, as well as multiple balloon dilatation or too rapid dilatation and too high pressure, so the balloon should be dilated slowly during the operation, paying attention to the pressure of dilatation, preferably under fluoroscopy to observe the process of balloon dilatation. After dilatation, imaging should be performed to observe whether there is any sandwich formation, so that the stent can be placed in time to make the sandwich adhere to the wall.
(3) Advantages of PTA
Balloon dilation and stenting of lower extremity arteries is a safe and minimally invasive treatment technique that can rapidly re-establish blood flow to the limb, improve tissue blood supply, and win healing time for ulcer healing or toe amputation wounds, especially for elderly, critically ill and high-risk patients, and is an effective method to save the limb. Moreover, endoluminal treatment is reproducible and can be re-dilated by minimally invasive methods when restenosis occurs. Even if the procedure fails, its impact on further stenting or vascular bypass surgery is not significant and can be used as an early treatment for lower limb ischemia.
Interventional endovascular treatment has become the treatment of choice because of its minimally invasive, reproducible operation and precise efficacy.