WCA was first described by Sane and Vidaillet in 1988 [4]. WCA is a rare and underdiagnosed congenital anomaly that involves multiple thin and tortuous epicardial arterial conduits that reassemble distally into a single lumen [5]. WCA is common in the RCA (70.2%), and most patients are male (90.9%) [6, 7]. And recanalized thrombus in coronary arteries is also common in the RCA (66.7%) and some in the LAD(33.3%), few in the LCX[8].Recanalized thrombus occurs after thrombotic occlusion but can be easily misdiagnosed as WCA because it manifests similarly on angiographic images [9].
Although WCA is generally considered a benign incidental finding, cases of associated ischaemia, thrombus formation, atherosclerotic plaque formation, and sudden cardiac death have been reported [6, 10, 11]. Complex intracoronary channels affect blood flow and may cause a pressure drop in distal blood perfusion, particularly for patients with more complex microchannels and longer lesions. Although WCA shows normal TIMI flow or visual stenosis < 70% on coronary angiography, its sensitivity and specificity for assessing ischaemia are limited [12]. Since coronary artery dissection and recanalized thrombus appear similar to WCA on angiographic images, it is essential for clinicians to establish a differential diagnosis. Intravascular imaging such as OCT can help to clarify intracoronary artery instructions and detect intracoronary thrombi [5]. In WCA, OCT findings show that each narrow vessel has a three-layered vascular structure, and the vessels are not interconnected [5, 13, 14]. In contrast, on OCT, a recanalized thrombus divides the lumen into multiple small cavities that communicate with each other without a three-layered vascular structure [9]. Additionally, fractional flow reserve may be the most appropriate method for assessing ischaemia severity [12, 15].
PV is the most common myeloproliferative neoplasm, and thromboembolism is the most common complication[2]. The incidence of thromboembolism is 46%, and that of arterial thrombosis is 2–3 times higher than that of venous thrombosis [16]. This patient had been hospitalised for cerebral infarction more than 20 years ago, and routine blood examination showed an abnormal increase in red blood cell count. Therefore, PV is believed to increase blood viscosity, which likely led to cerebral infarction in this patient. In this case, OCT confirmed changes in the LAD that were consistent with an organised thrombus based on angiographic manifestations. Therefore, we assume that the lesions in the LCX and RCA were likely to be another organised thrombus, which is a complication of PV. Recanalized thrombus usually occurs in local or short lesions within a vessel [9]. However, in this case, recanalized thrombus in both the LAD and LCX was rare.
Currently, there is no consensus regarding the treatment of WCA or woven-like coronary arteries caused by recanalized thrombus. Channel distortion may lead to difficulties in wiring and device delivery, and endothelialisation of the tissue separating multiple channels may cause occlusion of the side branch. Therefore, treatment strategies should be prudent and individualised. Some previous studies showed that OCT-guided stent implantation may be reasonable for treating WCA [7, 13]. And intravascular ultrasound (IVUS) guidance is useful for ensuring that the wire traverses through the largest lumen and to manage stent position and expansion in the WCA with chronic total occlusion [17]. In addition, recanalized thrombus can also be implanted using OCT or IVUS [8, 12]. And a previous report showed that recanalized thrombus in the LAD of a patient with PV was treated by stent[18]. However, the most cases of recanalized thrombus showed it happened in a local or short lesions within a vessel [8, 9, 12, 18], if it happens in two or three vessels in a patient with PV, medical therapy may be the optimal treatment option.Therefore, we chose a conservative therapy for this patient. At 9 months follow-up, the patient's chest pain was relieved without any cardiac events.
Finally, patients with PV are susceptible to arterial thrombosis and recanalized thrombus in the coronary arteries is very similar to WCA on coronary angiography. Therefore, high-resolution cross-sectional images such as OCT would be needed for the diagnosis and differential diagnosis of it. And physicians should also take an appropriate treatment in a personalized way in patients with PV.