Extracranial carotid stenosis is one of the major causes of ischemic cerebrovascular disease. After atherosclerosis occurs, the bifurcation of the common carotid artery to the internal and external carotid arteries tends to form atherosclerotic plaque stenosis, which leads to transient ischemic attack (TIA), cerebral infarction and so on. Carotid endarterectomy (CEA) has been used for more than 50 years to relieve extracranial carotid stenosis and prevent ischemic stroke, and is now considered the treatment of choice for stroke prevention. From March 2005 to March 2007, a total of 16 cases of CEA were performed in our vascular surgery department, and not only did not have a single perioperative stroke event, but also had remarkable results in improving the preoperative cerebral ischemic symptoms, which are reported as follows.
1 Data and methods
1.1 General data Among the 16 patients, 11 were male and 5 were female, aged 40-81 years, with an average age of 63 years.
1.1.1 Cerebral ischemic symptoms Three cases had a history of cerebral infarction and hemiplegia for more than six months and had partially recovered; 8 cases had a history of recurrent typical TIA without cerebral infarction; 5 cases had atypical cerebral ischemic symptoms such as long-term headache, dizziness, tinnitus and photophobia without typical TIA symptoms; none had any neurological symptoms at all.
1.1.2 Clinical examination All 16 cases were diagnosed clearly by carotid color Doppler ultrasonography at the beginning, then one case underwent digital subtraction angiography (DSA) preoperatively, 8 cases used head and neck electron computed tomography angiography (CTA), 7 cases used head and neck magnetic resonance angiography (MRA), and all angiography examinations were to include the examination of intracranial Willis rings. Unilateral carotid stenosis lesion was used in 10 cases and bilateral in 6 cases; the more severe side of bilateral stenosis was selected for surgical treatment. The degree of carotid artery stenosis ranged from 50% to 95%. Among them, 7 cases underwent CEA on the left carotid artery and 9 cases on the right. Figure 1 and Figure 2 show the results of CTA and MRA arteriography in 2 cases of internal carotid artery stenosis, respectively.
1.1.3 Comorbidity There were 11 cases of hypertension, 4 cases of coronary heart disease and 2 cases of diabetes mellitus.
1.2 Treatment methods
1.2.1 Surgical anesthesia All 16 patients were firstly given cervical plexus anesthesia. After exposing one side of the carotid artery in the awake state, the patient was heparinized systemically (0.8-1.0 mg/kg), and the common, internal and external carotid arteries were clamped with arterial blocking forceps in the plaque-free area, respectively, for 15 minutes. If any of the above-mentioned symptoms appeared, the blocking clamps of the carotid arteries were released immediately, tracheal intubation was performed, and a carotid diversion tube was used to maintain intraoperative blood supply to the head.
1.2.2 Surgical operation Intraoperative diversion tube was not used in 13 patients, and intraoperative diversion was established in 3 cases. The plaque and intima were stripped in its entirety starting from the common carotid artery, transected proximally, and peeled toward the external carotid entrance and the distal internal carotid. The filiform intima is transected when the filiform intima is reached. The endothelial stump of the internal carotid artery must then be fixed with 6/0 Prolene wire to prevent postoperative formation of a living valve entrapment in the endothelium, resulting in severe internal carotid artery occlusion and thrombosis, or even stroke. The residual debris was flushed intracavernously with heparin saline, and a 5-cm section of saphenous vein patch (Patch) was routinely taken to close the arterial incision to prevent causing artificial arterial stenosis. The carotid artery was blocked for 18–28 min, with a mean of 21 min.
1.2.3 Postoperative management Heparin anticoagulation was started intravenously pumped 2h postoperatively and changed to warfarin after 5 days for 3 months orally, and INR was monitored to control it between 2.0 and 3.0. Postoperatively, mannitol and dexamethasone were routinely used to prevent cerebral edema and enhance cerebral protection.
2 Results
2.1 Postoperative results All 16 cases in this group underwent unilateral carotid atherosclerotic plaque and intimal debridement, among which 6 cases with bilateral lesions were operated on the side with more severe stenosis. There was no perioperative stroke or death in the whole group; 3 patients who had suffered from stroke showed significant improvement in consciousness and limb function 2 d after surgery; 8 patients with TIA symptoms showed 100% symptom relief, and 6 patients (75.0%) showed complete disappearance of symptoms; 5 patients with atypical neurological symptoms showed complete disappearance of symptoms in 3 cases and significant reduction of symptoms in 2 cases, and the apparent rate was also 100%, especially In particular, the preoperative symptoms of headache, tinnitus and photophobia were most significantly relieved after surgery, while the symptoms of dizziness and vertigo were slightly less improved. The postoperative transcranial Doppler showed that the cerebral blood flow was significantly higher than that before surgery.
2.2 Postoperative complications Four cases (25.0%) of sublingual nerve injury and one case (6.3%) of laryngeal recurrent nerve injury were treated conservatively for 1-3 months and then improved spontaneously.
2.3 Follow-up The whole group was followed up for 2-26 months, and one case died of heart attack at 18 months after surgery.
3 Discussion
Atherosclerotic cerebrovascular disease is a common disease that seriously threatens the lives of middle-aged and elderly people. Carotid atherosclerotic plaques narrow or even occlude carotid arteries and reduce cerebral blood flow, which can cause a series of lesions such as TIA, thrombosis and cerebral infarction. Once the carotid atherosclerotic plaque thrombus is dislodged, cerebral embolism can occur suddenly. Overseas cerebral angiography in patients with cerebrovascular insufficiency revealed that 40%-50% of the lesions were in extracranial vessels (1).
In 1951, Fishe published an article on the idea of transient ischemic attack (TIA) relief and stroke prevention through extracranial artery surgery, and in 1953, DeBakey performed CEA for the first time in patients with complete occlusion of the internal carotid artery and successfully reestablished blood flow, which led to the development of carotid artery surgery (2). However, there was a stagnation due to the subsequent poor surgical results. With the improvement of surgical techniques and selection of surgical patient indications, the complication rate of CEA surgery has decreased significantly and CEA has regained attention. The randomized trials showed that 3120 patients in 126 hospitals in 30 countries were randomized to CEA or drug therapy (including antihypertensives, anticoagulants, and lipid-lowering drugs) between 1993 and 2003 and then prospectively followed for 5 years with a mean follow-up of 3.4 years. The risk of stroke or death within 30 days of surgery was 3.1%; for patients younger than 75 years of age who underwent surgery, the 5-year risk of stroke was 6.4%; compared with 11.8% for drug therapy. This fully illustrates that carotid endarterectomy, despite its risks, has significant efficacy in preventing the occurrence of stroke.
With the increasing improvement of related technology, CEA has been rapidly promoted, and now nearly 100,000 cases are performed annually in the United States. Although carotid stenting is now widely used, Coggia et al. (5) showed that dislodgment of the embolus is still a major risk of this technique and is expensive. The procedure is effective in unblocking the carotid artery, improving cerebral blood supply, and preventing and treating strokes. The operation is simple and economical. It should be considered as the first choice especially among the economically disadvantaged people in China. The following is a preliminary discussion of the problems related to the operation in the context of this group of cases.
For patients with TIA or other atypical cerebral neurological symptoms who are older than 50 years old, we recommend routine carotid color ultrasound for initial screening of carotid stenosis, and further arteriography if carotid stenosis is confirmed. This invasive test has been associated with certain complications. In recent years, with the development of imaging, CTA and MRA can obtain vascular images similar to DSA, which can be applied to the diagnosis of carotid and cranial vascular diseases, not only to reduce the possibility of complications during the examination, but also to reflect the tissue structure of the carotid stenosis site more realistically. In this group of 16 cases, one DSA arteriogram, eight carotid CTA examinations and seven MRA examinations were performed. Carotid plaque imaging was clear and accurately localized, and the degree of stenosis was determined to be completely consistent with what was seen intraoperatively. All angiograms should include the examination of the intracranial Willis loop, which is one of the main bases for assessing whether Shunt is required intraoperatively.
The currently accepted indications for surgery are: >70% stenosis of one internal carotid artery or >50% stenosis with symptoms of TIA. If there has been a previous stroke with incomplete improvement of hemiplegic symptoms, it is listed as a contraindication to surgery by some scholars, who consider that irreversible necrosis of brain tissue has occurred and there is no surgical value. However, from our cases, we found that three cases had a history of previous stroke, and one of them also had three consecutive severe strokes within two years, and none of the hemiplegic symptoms resolved with conservative treatment, but the recovery of hemiplegia after CEA surgery was significantly improved compared with the previous conservative treatment, and one patient’s neurological symptoms even disappeared completely. Therefore, we believe that previous history of stroke is not an absolute contraindication to surgery, and if the carotid lumen is present and not 100% occluded, there are still indications for surgery, which is beneficial to improve the regeneration of nerve tissue. In addition, although some patients do not have a typical history of TIA, and the degree of carotid stenosis is only about 50%, they have long-term atypical cranial nerve symptoms, such as long-term severe migraine, photophobia, and syncope when waking up, which do not improve with long-term conservative treatment. Therefore, we believe that for experienced surgeons, the indications for CEA surgery should be relaxed appropriately.
3.3 Whether to establish Shunt intraoperatively Some scholars advocate the routine use of Shunt, while most scholars do not advocate this step because they believe that it can increase the risk of cerebral embolism. The choice of using Shunt should usually consider the following points: (1) the degree of preoperative contralateral carotid stenosis; (2) the severity of preoperative symptoms; and (3) intraoperative EEG monitoring or transcranial vascular Doppler monitoring. We have also added the following judgment bases to this: ① routinely include the examination of the Willis loop during the action pulsography to understand whether its structure is intact and whether sufficient blood traffic can be formed from the contralateral side; ② routinely perform carotid plexus anesthesia first and perform carotid artery clamping test, if the patient can tolerate 15 minutes of clamping, then Shunt is not necessary; ③ after clamping the internal carotid artery, use transducer to measure Of our 16 patients, 13 did not use Shunt intraoperatively, and none of them had any neurological symptoms after surgery. We believe that skill and gentleness are the main factors to reduce postoperative stroke in CEA surgery, and since the process of placing Shunt will increase the number of surgical steps and even crush and dislodge the plaque, it is better not to use Shunt as long as the above conditions are met.
3.4 How to reduce the occurrence of intraoperative and postoperative strokes The causes of intraoperative and postoperative strokes are related to prolonged intraoperative carotid artery block, carotid plaque dislodgement in the human brain and carotid thrombosis. Our preventive measures are to minimize the intraoperative blocking time or use Shunt, to remove the debris of the trabecular endothelium carefully and thoroughly, and to open the blood flow in the order of the common carotid artery first, then the external carotid artery, and finally the internal carotid artery, if there is small particles of blood flow will also be washed into the external carotid artery. Immediately after opening the flow, 250 ml of 20% mannitol is given intravenously to lower intracranial pressure and maintained until at least 72 h postoperatively, alternating with dexamethasone or hypertonic glucose if necessary, while controlling hypertension to prevent excessive cerebral perfusion from occurring. Postoperatively, anticoagulation measures such as small doses of heparin or antiplatelet agents were given, and satisfactory results were achieved. All patients in this group used autologous saphenous vein patches to prevent stenosis after carotid suture. Due to the small number of cases in this group and the rigorous preoperative screening of cases, no serious complications have been encountered.
From our results, CEA should be a very safe and reliable procedure, and although it has been considered as a prophylactic procedure, from our case analysis, it also has the efficacy of treating hemiplegia symptoms after stroke and improving various cerebral ischemic symptoms.