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Congenital coronary artery ostial disease: a spectrum of anatomic variants with different pathophysiologies and prognoses.

2012; National Institutes of Health; Linguagem: Inglês

Paolo Angelini,

Cardiovascular Issues in Pregnancy

Coronary ostial stenosis or atresia (COSA, a new acronym) is a spectrum of rare developmental conditions with different pathophysiologic mechanisms and clinical implications. Together, the various forms of COSA should be considered a subclass of congenital coronary artery anomalies (CAAs). Although COSA includes various entities, these entities have two features in common. First, the defect is congenital, although it may progress during pre-natal and postnatal life. Second, the developmental defect causes ostial or proximal coronary obstruction (that is, stenosis or atresia). A fundamental distinction must be made between COSA and a related condition that involves the ectopic origin of a coronary artery from the opposite coronary artery (which is frequently, although erroneously, called “single coronary artery”). Here, I present an in-depth discussion of COSA (Table I) to aid the clinical understanding and management of individual cases. TABLE I. Defining Features of COSA By definition, COSA is congenital1–6; however, in some clinical adult cases, it can be difficult to determine whether a given defect has been present since birth.7–9 Also, total or partial-obstruction COSA might not be recognized until late after birth, by which time mild or nonexistent functional stenosis at birth might have become severe or totally occlusive (atretic). In adult patients with coronary ostial or proximal coronary stenosis, it can be difficult to rule out acquired causes, such as arteritis, which can produce conditions morphologically similar to COSA; for example, atherosclerotic, syphilitic, Kawasaki, and Takayasu aortitis have all been cited as causes of acquired ostial stenosis or occlusion.7–9 The absence of significant risk factors for atherosclerosis is relevant to the diagnosis of COSA but, by itself, is inconclusive. Coronary ostial stenosis or atresia affects the left coronary artery (L-COSA) more frequently than it does the right coronary artery (R-COSA). The aortic ostium in a case of COSA can be in the normal location or at an ectopic site. When the left ostium is located at a sinus of Valsalva that is abnormal for the distal coronary distribution, the case is one of anomalous coronary artery origin from the opposite sinus with intramural course (ACAOS),10 in which the proximal “crossing” trunk is stenotic because it is located intramurally (passing to the correct side of the heart, taking a tangential direction off the ostium, and lying within the aortic wall). Other features present in some cases of COSA include an ostial dimple (a rudiment of the coronary ostium that is usually followed more distally by proximal coronary stem atresia11) and a blind distal left main trunk, which is best appreciated upon computed tomographic angiography. In COSA, the presence of only 1 or 2 full-diameter connecting collateral vessels (without narrowing at the transition between the providing and the receiving vessel, as shown in Fig. 1) is suggestive of congenital origin in any given case of ostial stenosis or atresia. In contrast, in cases of postnatally acquired collateral vessels, one should expect a rich network of channels that typically involves all of the septal, infundibular, and atrial branches. In addition, such acquired collateral vessels enlarge progressively after birth, and they are typically smaller than the distal recipient vessels; this “step-up phenomenon” is typically observed only in postnatally acquired collateral vessels. Collateral vessels with similar features occur in atherosclerotic occlusion of coronary vessels, as well as in anomalous origin of the left or the right coronary artery from the pulmonary artery.12 Fig. 1 Four selective coronary angiographic still images of the right coronary artery, obtained in a 52-year-old patient with chronic, atypical chest pain. The images were obtained in left anterior oblique (caudal and cranial: A and B) views, and 30- ... The absence of clinical angina (or ischemia at stress testing) tends to confirm the diagnosis of COSA, rather than acquired ostial stenosis or atresia. Similarly, myocardial scarring, which implies an event of acute ischemic myocardial damage, is rare in patients with COSA. As a corollary, only rarely is a surgical bypass intervention required to treat congenital coronary ostial atresia: the collateral vasculature is usually adequate. Single Coronary Artery “Single coronary artery” is a misnomer: because all of the normal coronary arteries are present (that is, right, left anterior descending, and circumflex), this entity is not defined by the presence of a single coronary “artery” but by the fact that all these arteries originate from a single ostium.12 This term is clinical jargon (convenient but incorrect) used in some of the literature to refer to cases of CAA that feature a single coronary ostium, which provides flow to the whole coronary tree without interruption of continuity and without evidence of collateral vessels. Table II lists subtypes of this condition.12 In essence, these anomalies consist of the ectopic origin of the right or left coronary artery from the opposite sinus, which artery shares a proximal common trunk with the normally originating coronary artery. Less frequently, the ectopic artery originates from a distal segment of the contralateral artery, such as when the left coronary artery originates from the right coronary artery at the crux and takes a posterior course at the atrioventricular groove. The proximal trunk is a common, mixed-nature trunk that generally provides normal blood flow to both coronary arteries. Coronary stenosis or atresia is missing in this condition (hence it is not a type of COSA) unless the ectopic vessel has the above-mentioned proximal stenosis, caused by an intramural pre-aortic course. This latter course is also called “between aorta and pulmonary artery”10,12 (and it results in a form of COSA, when significant stenosis occurs), but this label is inaccurate, because the artery's proximal, ectopic coronary segment lies inside the aortic wall, and not in the space between the 2 great arteries. TABLE II. The Most Common Courses of Ectopic Coronary Arteries that Originate from the Opposite Sinus of Valsalva It has become clear, mainly from recent experience with intravascular ultrasonographic imaging,10 that the pre-aortic course always features intramural location of the proximal coronary trunk inside the wall of the aorta. The name recently proposed for such anomalies is ACAOS,10 and this condition is indeed the most common form of COSA. The severity of the resulting intramural stenosis in cases of ACAOS is variable, ranging from minimal stenosis to atresia, and it depends both on the degree of hypoplasia of the intramural segment and on the amount of lateral compression. The possibility that the extreme degrees of stenosis associated with ACAOS could lead to total or functional atresia, preventing all prograde flow from the ectopic ostium, must be considered in any given case of coronary ostial atresia (whether anatomic or functional). An exceptional example of ACAOS with COSA is shown in Figures 1 and ​and22. Fig. 2 Computed tomographic angiogram of the same patient shows a proximal left main trunk, the presence of which was not suggested by the selective coronary angiograms (Fig. 1). Indeed, the proximal left main trunk must be severely stenotic as a consequence ...