Anatomic variants of the normal coronary artery circulation

Transcription

1 Diagnosis and Operation for Anomalous Circumflex Coronary Artery Keishi Ueyama, MD, PhD, Mahesh Ramchandani, MD, Arthur C. Beall, Jr, MD, and James W. Jones, MD, PhD Department of Surgery, Baylor College of Medicine, and Surgical Service, Houston Veterans Affairs Medical Center, Houston, Texas Background. Origin of the left circumflex coronary artery from the right sinus of Valsalva is the most common anatomic variation of the coronary artery circulation. However, there are few reports about the operative approach to this anomalous vessel. Methods. Forty patients having this anomaly were identified from 10,216 adult cardiac catheterization procedures. Forty percent of the anomalous circumflex coronary arteries (ACCAs) had critical atherosclerotic lesions. Eighty cases needed bypass grafting. Results. For diagnosis of ACCA, the aortic root sign was positive in 94.9% of the diagnosed patients and the nonperfused myocardium sign was found in 92.5%. Eighty percent of ACCAs were larger than 2 mm in radiographic diameter before their passage into the atrioventricular groove. However, after emerging from the atrioventricular groove, 70% measured less than 1.5 mm. Consequently, a technique was developed to bypass the proximal ACCA and was used in 2 cases. Six other patients with more distal disease and larger vessels underwent conventional bypass grafting. Conclusions. The aortic root sign and nonperfused myocardium are useful in diagnosing ACCA. The ACCA is usually too small for use of the conventional graft technique. Therefore, a technique was developed to graft more proximally and was applied successfully in 2 cases. (Ann Thorac Surg 1997;63:377 81) 1997 by The Society of Thoracic Surgeons Anatomic variants of the normal coronary artery circulation have been found in 0.6% to 1.55% of all patients undergoing coronary angiography [1 9]. These anomalies are present at birth, but relatively few are symptomatic during childhood. Most anomalies are discovered as incidental findings during coronary arteriography or at autopsy. Origin of the left circumflex coronary artery from the right sinus of Valsalva is one of the most common anatomic variations of the coronary artery circulation [1 9]. This anomaly is classified as a benign asymptomatic anomaly [9 11]. Whether the anomalous circumflex coronary artery (ACCA) originates from a separate orifice or as a branch of the right coronary artery, the course is always retroaortic [1, 4 6, 8 10, 12], and this may impose certain technical difficulties during operation. With the greater numbers of patients undergoing coronary revascularization, this knowledge has increasing relevance to cardiac surgeons. Material and Methods The database consisted of all patients undergoing coronary arteriography at the Houston Veterans Affairs Medical Center from 1983 to Patients with ACCAs were identified and served as the study group. All patients were adults. Accepted for publication July 25, Presented at the Twenty-second World Congress of the International Society for Cardiovascular Surgery, Kyoto, Japan, Sep 10 14, Address reprint requests to Dr Ueyama, Department of Surgery, Fukui Cardiovascular Center, Shinbo Fukui, 910, Japan. The aortic root sign and the nonperfused myocardium sign [10] provided clues to the presence of an ACCA. Diagnosis was then made by selective angiographic studies. Results Forty patients having this anomaly were identified from 10,216 adult cardiac catheterization procedures during an 8-year period. The incidence was 0.39%. Diagnosis of an ACCA is made reliably with previously described signs, of which the aortic root sign is one [10] (Fig 1). This is seen in the right anterior oblique projection of the left ventriculogram as a button projecting from the aortic root. The other sign indicating an ACCA is the nonperfused myocardium sign [10]. This can be viewed with the left coronary injection in the right anterior oblique projection. The left anterior descending coronary artery appears smaller than usual, without any sign of a circumflex artery perfusing the obtuse angle of the myocardium (Fig 2). The aortic root sign was present in 37 of 39 cases of ACCA, yielding a sensitivity of 94.9%. The nonperfused myocardium sign was seen in 37 of 40 similar cases, for a sensitivity of 92.5%. Fourteen of 40 cases of ACCA arose from a separate orifice in the right sinus of Valsalva, with the remainder arising as a branch of the right coronary artery. In all cases, the ACCA passed behind the aorta before entering the atrioventricular groove. Forty percent of ACCAs (16 of 40) in this series had substantial atherosclerotic lesions, and 42.5% of normally 1997 by The Society of Thoracic Surgeons /97/$17.00 Published by Elsevier Science Inc PII S (96)

2 378 UEYAMA ET AL Ann Thorac Surg ANOMALOUS CIRCUMFLEX CORONARY ARTERY 1997;63: originating coronary arteries (34 of 80) in the same patients had similar lesions (Fig 3). In this study, 80% (32 of 40) of the ACCAs were more than 2 mm in radiographic diameter between their origin and their passage into the posterior atrioventricular groove. However, after emerging from the atrioventricular groove, 70% (28 of 40) of these vessels measured less than 1.5 mm, the conventional minimum diameter for grafting [13] (Fig 4). A technique was developed to bypass the proximal anomalous artery. The proximal segment of the ACCA can be found behind the aorta. Decompression and rotation of the proximal ascending aorta allowed easy access to the proximal and middle segments of the anomalous vessels (Fig 5). The proximal aortic anastomosis should be fashioned more posteriorly than usual to Fig 2. During selective opacification of the left coronary artery in the right anterior oblique projection, one sees a large area of nonperfused myocardium between the coronary artery and the posterior lateral cardiac border. This is called the nonperfused myocardium sign. avoid kinking of the vein graft. This technique was used in 2 cases (Fig 6). Six other patients had their anomalous circumflex vessels bypassed in a conventional manner because of important distal disease in a vessel of adequate caliber for grafting. Fig 1. Left ventriculography of the right anterior oblique projection shows the anomalous circumflex coronary artery in profile. This anomalous circumflex coronary artery is located posteriorly behind the right sinus of Valsalva and is called the aortic root sign. Comment Origin of the left circumflex coronary artery from the right sinus of Valsalva is the most common anatomic variation of this coronary artery. The incidence of this anomaly is 0.20% to 0.71% in reported series [1 9] (Table 1). The oblique takeoff of the anomalous artery causes a slitlike orifice in the aortic wall and is capable of collapsing in a valvelike manner; however, it is rare for this to cause symptoms or sudden death. This anomaly is con-

3 Ann Thorac Surg UEYAMA ET AL 1997;63: ANOMALOUS CIRCUMFLEX CORONARY ARTERY 379 Fig 3. Coronary disease of the anomalous circumflex artery. In (A), the right coronary artery was also diseased. In (B), the left anterior descending coronary artery was opacified through the collateral artery. sidered benign [9 11] and is usually detected as an incidental finding on coronary angiography. However, many cases may be overlooked if the angiographer assumes that the vessel is occluded or congenitally absent. Given the 40% incidence of substantial lesions in these vessels, this may contribute to an unfortunate Table 1. Incidence of Circumflex Coronary Artery Anomalies: Angiographic Series First Author Total Patients Circumflex Anomalies Incidence (%) Fig 4. Radiographic diameter of the anomalous circumflex coronary artery. Eighty percent (32/40) of these vessels were more than 2 mm before entering the atrioventricular groove. However, after exiting the atrioventricular groove, 70% (28/40) of these vessels were less than 1.5 mm. Liberthson [1] Not stated Engel [2] 4, Chaitman [3] 3, Baltaxe [4] 1, Kimbiris [5] 7, Sheldon [6] 38, Donaldson [7] 9, Wilkins [8] 10, Yamanaka [9] 126, Ueyama 10,

4 380 UEYAMA ET AL Ann Thorac Surg ANOMALOUS CIRCUMFLEX CORONARY ARTERY 1997;63: Fig 5. Approach to the proximal site of the anomalous circumflex coronary artery (ACCA). (IVC inferior vena cava; RA right atrium; RCA right coronary artery; SVC superior vena cava.) outcome for the patient. Furthermore, the mere presence of ACCA may be important information, alerting the surgeon, for example, to avoid compression of the vessel during valve replacement [14]. In this study, both of the previously described signs proved to be useful in identifying an ACCA. Because of the peculiar anatomic configuration, this anomaly does not lend itself well to percutaneous coronary angioplasty. Therefore, the surgical revascularization of the ACCA is meaningful. Graft patency increases in proportion to native vessel diameter, and if conventional grafting techniques are used in cases of ACCA, 70% of the vessels grafted will be less than 1.5 mm in Fig 6. Bypass grafting to the proximal site of the anomalous circumflex coronary artery. diameter, an important correlate of graft failure [13]. If the segment of the ACCA that is diseased is proximal, a large area of myocardium may be in jeopardy. Our technique allows proximal grafting of the diseased ACCA, where the diameter is usually greater than 2.0 mm. The only potential difficulty is graft kinking, and the technique addresses this problem by emphasizing careful selection of the site of the proximal anastomosis. In this series, 16 of 40 cases of ACCA showed substantial disease, and 8 were grafted. In 6 of these 8, the disease was distally located and the conventional technique was used. The technique was used successfully in 2 cases. In the 8 patients in whom no graft was placed to the ACCA, the target vessel had distal disease and was deemed too small for grafting. In conclusion, the incidence of coronary atherosclerosis is similar between ACCA and other coronary arteries. The aortic root sign and the nonperfused myocardium sign are useful in diagnosing an ACCA. The ACCA initially pursues a retroaortic course and is usually less than 1.5 mm in diameter after emerging from the atrioventricular groove. Therefore, a technique was developed to graft this vessel more proximally and was successfully applied in 2 cases. References 1. Liberthson RR, Dinsmore RE, Bharati S, et al. Aberrant coronary artery origin from the aorta: diagnosis and clinical significance. Circulation 1974;50: Engel HJ, Torres C, Page HL Jr. Major variations in anatomical origin of the coronary arteries: angiographic observations in 4,250 patients without associated congenital heart disease. Cathet Cardiovasc Diagn 1975;1: Chaitman BR, Lespérance J, Saltiel J, Bourassa MG. Clinical, angiographic, and hemodynamic findings in patients with anomalous origin of the coronary arteries. Circulation 1976; 53: Baltaxe HA, Wixson D. The incidence of congenital anomalies of the coronary arteries in the adult population. Radiology 1977;122: Kimbiris D, Iskandrian AS, Segal BL, Bemis CE. Anomalous aortic origin of coronary arteries. Circulation 1978;58:

5 Ann Thorac Surg UEYAMA ET AL 1997;63: ANOMALOUS CIRCUMFLEX CORONARY ARTERY Sheldon WC, Hobbs RE, Millit D, Raghavan PV, Moodie DS. Congenital variations of coronary artery anatomy. Cleve Clin Q 1980;47: Donaldson RM, Raphael M, Radley-Smith R, Yacoub MH, Ross DN. Angiographic identification of primary coronary anomalies causing impaired myocardial perfusion. Cathet Cardiovasc Diagn 1983;9: Wilkins CE, Betancourt B, Mathur VS, et al. Coronary artery anomalies: a review of more than 10,000 patients from the Clayton Cardiovascular Laboratories. Tex Heart Inst J 1988; 15: Yamanaka O, Hobbs RE. Coronary artery anomalies in 126,595 patients undergoing coronary arteriography. Cathet Cardiovasc Diagn 1990;21: Page HL Jr, Engel HJ, Campbell WB, Thomas CS Jr. Anomalous origin of the left circumflex coronary artery: recognition, angiographic demonstration and clinical significance. Circulation 1974;50: Taylor AJ, Rogan KM, Virmani R. Sudden cardiac death associated with isolated congenital coronary artery anomalies. J Am Coll Cardiol 1992;20: Angelini P. Normal and anomalous coronary arteries: definitions and classification. Am Heart J 1989;117: Crosby IK, Wellons HA Jr, Taylor GJ, Maffeo CJ, Beller GA, Muller WH Jr. Critical analysis of the preoperative and operative predictors of aortocoronary bypass patency. Ann Surg 1981;193: Roberts WC, Morrow AG. Compression of anomalous left circumflex coronary arteries by prosthetic valve fixation rings. J Thorac Cardiovasc Surg 1969;57:834 8.