Introduction

Coiling (or looping) of the artery is a rare morphologic entity, most frequently described in the internal carotid artery (ICA) as a single cause of cerebrovascular insufficiency or combined with carotid atherosclerosis (₁,₂,₃,₄). Although incidence of coiling and kinking of internal carotid artery has been estimated to be from 10% to 16% in general population, respective clinical significance still remains the ground of controversy (₅). Morphological anomalies of the extracranial internal carotid artery (ICA) cause symptomatic cerebrovascular insufficiency in 4-16% of the cases (₆).

Case Presentation

Our case was a 46-year-old male who has had experienced a cerebrovascular accident 3 years ago with monoparesia sequela of the right arm and acquired loss of speech for 2 months increasing in intensity. For this reason he has been hospitalized at Department of Neurology in a different health facility. Color Doppler investigation of carotid and vertebral arteries revealed diffuse intimal hyperplasia of 3 mm in thickness throughout left ICA. Peak systolic flow velocity was measured as 221/95 cm/s corresponding to a stenosis of more than 80% (Figure 1).

Figure 1

Figure 1: Color Doppler image before admission showing 80% stenosis in left ICA.

Cranial MRI showed encephalomalasia of left frontal, occipital, parietal and partly temporal lobes. Hence, enlargement of left lateral ventricle comparing to right hemisphere was seen. Arteriogram showed an unusual coiling of almost 360° in left extracranial internal carotid artery (Figures 2 and 3).

Figure 2

Figure 2: Coiling lesion of left extracranial ICA and arteriographic image showing the preocclusive image.

Figure 3

Figure 3: The DSA image(left) with selective injection of the left CCA shows coiling of the internal carotid artery and an associated severe stenosis at its origin.

A preocclusive stenosis of 99% prior to coiling segment was also demonstrated. The ankle-brachial pressure index was 1.0 in both legs. On examination there was no pulsatile mass in the neck, and the carotid pulsations on both sides were normal. Blood pressure values were in the normal range. Electrocardiographic and ultrasound examination of the heart were unremarkable. The patient had no significant changes in standard biochemical findings on admission. He was a nonsmoker. The cholesterol and triglyceride levels were within the normal range.

Surgical Technique

Surgery was performed with the patient under general anesthesia. Classic carotid incision lying between jugular notch and earlobe was made. Skin, subcutaneous tissues and platysma muscle were dissected. Arterial region was reached in front of medial border of sternocleidomastoid muscle. Facial vein was transected and ligated. CCA and ECA were suspended. ICA was dissected up to mastoid process. Three to 4 centimeters distal to carotid bulb, ICA became extremely thinner. ICA part containing the coiling segment was identified just after beginning of this thinning and at posterior region (Figure 4).

Figure 4

Figure 4: Perioperative image showing the coiling lesion.

In order to correct this coiling, coiling segment was freed via transecting at where it emerged from CCA. It was elongated to the most distal part of CCA and anastomosed in an end-to-side fashion (Figure 5).

Figure 5

Figure 5: Image of the coiling segment after re-implantation.

Duplex ultrasonography performed 21 days later showed patency and adequate flow through the anastomosed part of the artery. In the 2-month postoperative follow-up period he showed a marked improvement in loss of speech and the patient is well.

Discussion

In embryonic development,a pair of longitudinally directed channels arises in a paramedian location in the embryo on approximately the 19th day.These ultimately become the dorsal aortae.The ventral aortic sac connects to the dorsal aortae via the paired first aortic arches form, coursing around the five brachial arches by the 32nd day.The third arches are precursors of the carotid system,and the fourth arches develop asymmetrically. The right fourth arch,together with part of the right dorsal aorta,forms the proximal right subclavian artery.The left fourth arch remains continuous with the aortic sac and the left dorsal aorta to form the left aortic arch in postnatal life. The first and second arches substantially involute by the 29th day,and the dorsal aortae also regress between the third and fourth arches;this structure is called the ductus caroticus by the 6th week.The regression of these vascular segments leaves one predominant connection to the cranial region that courses from the ventral aortic sac through the third aortic arch to the cranial extension of the dorsal aorta. The combination of the ventral aortic sac,the third aortic arch,and the dorsal aorta rostral to the arch forms the common and internal carotid arteries. According to the most accepted view,if the ductus caroticus does not involute and if it persists into postnatal life, it forms a separate origin of the internal carotid artery,and this formation occurs in conjunction with involution of the third aortic arch that normally persists and becomes the common carotid artery and proximal internal carotid artery(₇).In conclusion; the carotid artery is formed by the third aortic arch and the dorsal aorta. During embryologic development, there is a prominent bend at the junction of these vessels. As the heart descends into the thorax, these vessels straighten, but kinking can occur if the straightening process is incomplete. Carotid coils, conversely, occur in adults and most frequently in the elderly, in whom atherosclerosis is also frequently present. Coiling may be acquired from excessive elongation of the artery with age, and the elongated artery may have thinning of the media and fragmentation of elastic lamina (₃).

Coiling of the carotid artery may produce luminal narrowing, which could lead to turbulent blood flow and subsequent intimal ulceration and embolization. Symptoms therefore could be similar to those caused by atherosclerotic disease of the carotid bifurcation, and patients may present with strokes, hemispheric TIAs, or amaurosis fugax (₃). Flow abnormalities were related to head turning, which is a characteristic feature of symptoms caused by carotid artery coiling (₈). Thus, when focal neurologic deficits of vertebral basilar insufficiency can be reproduced by head motion, the clinician should suspect a carotid coiling or kink (₃). Cerebrovascular hemodynamic changes mainly from kinking and in a lesser degree from coiling, have been documented with oculoplethysmographic and angiographic differences, accompanying positional changes of the head. The opposite view however, that similar variations represent a benign and incidental finding, has been also expressed (₅).

There is no universal agreement regarding the potential for alleviation of cerebrovascular symptoms by surgical repair of tortuous kinked or coiled carotid arteries (₃). Numerous angiographic and autopsy studies have shown that carotid redundancy is not uncommon and that most individuals with this anatomic variant remain asymptomatic (₃,₉). However, there is a subset of patients whose anatomy produces cerebrovascular symptoms as a direct consequence of carotid angulation. One of the largest angiographic series was reported by Weibel and Fields, who described 2453 carotid angiograms in 1438 patients. Coiling of the internal carotid artery was observed in 88 (6%), and kinking in 65 (5%) (₁₀). Del Corso and colleagues reported that atherosclerosis, hypertension, and aging may play an important role in producing carotid abnormalities, with aging seeming to be more important than atherosclerosis (₃,₁₁).

Operative indications were determined on the basis of symptoms compatible with brain ischemia. In all instances of isolated kinking and coiling, straightening was obtained by segmental resection of the common carotid artery and end to end anastomosis. In cases with associated occlusion, transection of internal carotid artery at its origin and re-implantation in the lateral aspect of the common carotid, was the remedy of choice (₅). However, Ballotta and associates suggested that surgery provides better results than medical treatment in patients with symptomatic carotid abnormalities (₃,₁₂).

Correspondence to

Doç. Dr. Ufuk YETKİN 1379 Sok. No: 9,Burç Apt. D: 13 35220, Alsancak – İZMİR / TURKEY Tel: +90 505 3124906 Fax: +90 232 2434848 e-mail: ufuk_yetkin@yahoo.fr