窦房结动脉形态学的320排CT研究

目的 使用320排CT冠状动脉造影（CTCA）研究窦房结动脉的形态特征,并描述其临床意义.方法 回顾性分析3144例患者[男1991例,女1153例,年龄（59±14）岁]的320排CTCA影像资料.由于图像质量不佳,51例患者被排除.根据分别起源于右侧冠状动脉或左回旋支确定为右或左（R或L）窦房结动脉；根据其各自走行于右心耳内侧或右心房的后面确定为R1或R2亚型；根据其各自的走行于左心耳内侧、后侧或左心房的后面确定为L1、L2或L3.然后,每种类型根据走行末端终止于上腔静脉周围的关系再分为上腔静脉前、上腔静脉后和上腔静脉周围型.如果窦房结动脉起源于右侧冠状动脉中段,走行于左心耳内侧,另外增加一个亚型（R1M）.S-型窦房结动脉起源于左旋支,向后走行于左心耳和左上肺静脉开口之间,然后向前终止于左心房的前壁.结果 3093例中共显示窦房结动脉3082例（96.4％）,其中2943例（95.5％）为单支窦房结动脉,1669支（54.2％）起源于右侧冠状动脉,1274支（41.3％）起源于左侧冠状动脉旋支.139例（4.5％）为双支窦房结动脉,并且为左右各1支,分别起源于右侧冠状动脉和左侧冠状动脉旋支.本文最常见的亚型是R1型1753支（54.4％）,其次是L1型805支（25.0％）和L2型551支（17.1％）,少见的亚型包括P,2型45支（1.4％）、L3型57支（1.8％）和R1m型10支（0.3％）.3221支窦房结动脉终止类型包括上腔静脉前、上腔静脉后、上腔静脉周围型分别有552支（17.1％）、1836支（57.0％）、833支（25.9％）.不同窦房结动脉起源的终止类型之间差异无统计学意义（x2 =1.32,P=0.25）.右窦房结动脉起点与右侧冠状动脉开口间距离为（13.8 ±8.4）mm；左侧窦房结动脉起点与左侧冠状动脉回旋支开口间距离为（11.7±6.1）mm,两者差异无统计学意义（t=0.764,P=0.476）.右窦房结动脉直径为（1.66±0.29）mm,左窦房结动脉直径为（1.61±0.26）mm,两者差异无统计学意义（t=0.844,P=0.557）.S型窦房结动脉被发现31例（2％）.结论 320排CTCA描述了窦房结动脉常见的分型,可以为外科和介入手术提供有价值的信息,以避免医源性损伤.显示窦房结动脉的变异相当有效、可靠.

The morphology of sinuatrial nodal artery on 320-raw computed tomography coronary angiography

Objective To use 320-raw computed tomography coronary angiography （CTCA）to investigate the morphologic characteristics of the sinoatrial node （SAN） artery and to describe its clinical implications.Methods 320-raw CTCA of 3144 patients [1991 men,1153 women; mean age （59 ± 14） years] were retrospectively reviewed.51 patients were excluded due to poor image quality.According to the origin,number,anatomic course,mode of termination of the SAN artery,each artery was classified into one of following types：right or left （R or L）,according to respective origin from the right coronary artery （RCA） or left circumflex （LCX） ; subtypes R1 or R2,according to its respective course medial to the right auricle or on the posterior surface of the right atrium; or L1,L2 or L3,according to its respective course,medial,or posterior to the left auricle or,on the posterior surface of the left atrium.Then,each type was subdivided according to the course of the terminal segment around the superior vena cava being precaval,retrocaval,or pericaval.The S-shape SAN artery arises from the posterolateral part of the left circumflex below,or behind the left auricle,and runs posteriorly between the left atrial appendage and the ostium of the left superior pulmonary vein,and then anteriorly close to the anterior wall of the left atrium.Results The SAN artery was visualized in 3082（96.4%） of 3093 cases.The SAN artery was being vascularized by a single artery in 2943（95.5%）cases and by two arteries in 139（4.5%）cases.It was arising from the RCA in 1669（54.2%）cases,from the LCX in 1274（41.3%）cases.The most frequent subtype in our study was R1 in 1753（54.4%）,followed by L1 in 805 （25.0%）,and L2 in 551 （17.1%）.The rare subtype in our study included R2 in 45 （1.4%）,L3 in 57 （1.8%）,and R1m in 10（0.3%）.The termination types in the 3221 SAN arteries were precaval in 552（17.1%）,retrocaval in 1836 （57.0%）,and pericaval in 833 （25.9%）.There was no statistically significant relationship between the origin of the SAN artery and the course of the terminal segment （x2 =1.32,P =0.25）.The mean distance between the origin of the SAN artery from the RCA and the RCA ostium was （13.8 ± 8.4） mm,from the LCX and the origin of the LCX was（11.7 ±6.1）mm.The difference was statistically significant（t =0.764,P =0.476）.The mean diameter of the SAN arteries was （1.66 ± 0.29） mm in the right and （1.61 ± 0.26） mm in the left.Thedifference was statistically significant （t =0.844,P =0.557）,S-shaped the SAN artery was determined in 31 （2%）cases.Conclusions The 320-raw CTCA depiction of the variable arterial blood supply to the SAN may provide valuable information prior to any planned surgical or catheter-based interventional cardiac procedures in patients.It is considerably effective in depicting the various vascularization types of SAN.