Coronary artery anatomy in complete transposition of the great arteries

Techniques and pitfalls of coronary arterial reimplantation in anatomical correction of transposition

BACKGROUND AND AIM

We assessed the anatomical variations in coronary arterial patterns relative to the techniques of reimplantation in the setting of the arterial switch operation, relating the variations to influences on outcomes.

METHODS

We reviewed pertinent published investigations, assessing events reported following varied surgical techniques for reimplantation of the coronary arteries in the setting of the arterial switch procedure.

RESULTS

The prevalence of reported adverse events, subsequent to reimplantation, varied from 2% to 11%, with a bimodal presentation of high early and low late incidence. The intramural pattern continues to contribute to mortality, with some reports of 28% fatality. The presence of abnormal course relative to the arterial pedicles in the setting of single sinus origin was associated with a three-fold increase in mortality. Abnormal looping with bisinusal origin of arteries was not associated with increased risk.

CONCLUSION

The techniques of transfer of the coronary arteries can be individually adapted to cater for the anatomical variations. Cardiac surgeons, therefore, need to be familiar with the myriad creative options available to achieve successful repair when there is challenging anatomy. Long-term follow-up will be required to affirm the superiority of any specific individual technique. Detailed multiplanar computed-tomographic scanning can now reveal all the variants, and elucidate the mechanisms of late complications. Coronary angioplasty or surgical revascularization may be considered in selected cases subsequent to the switch procedure.

Commissural Malalignment as a predictor of coronary artery abnormalities in patients with transposition of great arteries

Background

In patients with transposition of the great arteries (TGA), commissural malalignment (CM) between semilunar valves may be associated with abnormal coronary (CA) pattern. We intend to assess the degree of CM with incidence of unusual CA anatomy.

Methods

We proposed a ratio to measure the distance of both ends of the anterior facing sinuses of the pulmonary valve from the facing commissure of the aortic valve. We labeled it as D1 and D2 distance. A ratio (C ratio) of the smaller distance (either D1 or D2 whichever is shorter) over the sum of both D1 and D2 was taken (D1 or D2 whichever is shorter / D1 + D2). We related this ratio with the incidence of the unusual CA anatomy in D-TGA patients.

Results

We had a total of 158 patients. We defined the point beyond which the C-Ratio becomes significantly associated with abnormal coronary artery pattern, this represents the median effective level (EL50). The EL50 of the C-Ratio was found to be equal to 31% (0.31). The prediction revealed that the CA pattern would most probably be usual when there is a minor commissural malalignment (C-Ratio less than the EL50) and most probably be unusual when there is a major malalignment (C-Ratio is greater than the EL50). The sensitivity was 71% and the specificity 88% (p-value < 0.0001).

Conclusions

The C-Ratio helps to categorize the degree of CM as minor (less than 0.31) or major (more than 0.31). A higher C-Ratio predicts a higher incidence of unusual CA pattern.

Subclavian revascularization in the age of thoracic endovascular aortic repair and comparison of outcomes in patients with occlusive disease

OBJECTIVE

Open surgical revascularization for subclavian artery occlusive disease (OD) has largely been supplanted by endovascular treatment despite the excellent long-term patency of bypass. The indications for carotid-subclavian bypass (C-SBP) and subclavian transposition (ST) have been recently expanded with the widespread application of thoracic endovascular aortic repair (TEVAR), primarily to augment proximal landing zones or treat endovascular failures. This study was performed to determine the outcomes of patients undergoing C-SBP/ST in the context of contemporary endovascular therapies and evolving indications.

METHODS

A prospective database including all procedures performed at a single institution from 2002 to 2012 was retrospectively queried for patients who underwent subclavian revascularization for TEVAR or OD indications. Patient demographics and perioperative outcomes were recorded. Patency was determined by computed tomography angiography in the TEVAR group. Noninvasive studies were used for the OD patients. Life-table methods were used to estimate patency, reintervention, and survival.

RESULTS

Of 139 procedures identified, 101 were performed for TEVAR and 38 for OD. All TEVAR patients underwent C-SBP/ST to augment landing zones (49% preoperative; 41% intraoperative), treat arm ischemia (8% postoperative), or for internal mammary artery salvage (2%). OD patients had a variety of indications, including failed stent/arm fatigue, 49%; asymptomatic >80% internal carotid stenosis with concurrent subclavian occlusion, 18%; symptomatic cerebrovascular OD, 13%; redo bypass, 8%; and coronary-subclavian steal, 5%. Differences in postoperative stroke and death, primary patency, or freedom from reintervention were not significant. The 30-day postoperative stroke, death, and combined stroke/death rates were, respectively, 10.8%, 5.8%, and 13.7% for the entire cohort; 8.9%, 7.1%, and 12.9% in TEVAR patients; and 15.8%, 2.6%, and 15.8% in OD patients. The 1- and 3-year primary patencies were, respectively, 94% and 94% for TEVAR and 93% and 73% for OD patients. Survival was similar between the groups, with an estimated survival rate of 88% at 1 year and 76% at 5 years.

CONCLUSIONS

Stroke risk in this contemporary series of C-SBP/ST performed for TEVAR and OD indications may be higher than previously reported in historical series. In TEVAR patients, this may be attributed to procedural complexity of the TEVAR in patients requiring subclavian revascularization. In OD patients, this is likely due to the changing patient population that requires more frequent concomitant carotid interventions. Despite the short-term morbidity, excellent bypass durability and equivalent long-term patient survival can be anticipated.

Can we better understand the known variations in coronary arterial anatomy?

Coronary arterial anatomy is remarkably diverse. Identification of surgical risk factors, however, requires description in a uniform fashion. Such description mandates that account be given of both aortic sinusal origin and variability in aortopulmonary relationships. Currently, however, it is rare to find all this information provided either in clinical reports or published reviews. In this review, therefore, we summarize why both these features are important, emphasizing the marriage of convenience between the aortic root position within the cardiac base and the arrangement of the epicardial coronary arteries. The inductive approach accounts for all potential variations.

Vertically oriented intramural right coronary artery in complete transposition of the great arteries: prospective recognition and surgical implications

This report describes a rare case of complete transposition of the great arteries (TGA) with an intramural right coronary artery arising well above the sinotubular junction. Additionally in this case, the left circumflex artery arose anomalously as a branch from the right coronary. Identification of this anatomic anomaly was made by transthoracic echocardiography before surgery. The patient underwent a successful arterial switch operation on day 6 of life. Due to the preoperative diagnosis of the unusual right intramural coronary artery, the coronary transfer technique during the arterial switch was altered, allowing preservation of the right coronary artery.

Arterial Switch Operation for Transposition of the Great Arteries With Coronary Arteries From a Single Aortic Sinus

BACKGROUND

The reimplantation of the coronary arteries from a single aortic sinus (single sinus coronary artery) in an arterial switch operation remains a technically challenging procedure. The technique of coronary transfer in this situation should be individualized depending on coronary ostial anatomy. We reviewed our techniques of coronary reimplantation with early and midterm results.

METHODS

Among 103 patients who underwent arterial switch operations from March 1994 to June 2004, 16 (15.5%) had single sinus coronary artery (median age, 9 days; mean body weight, 3.5 kg). Fourteen patients (14/16, 87.5%) had coronary arteries from right facing sinus (sinus 2). Of these 14 patients, 11 had separate ostia including intramural course of the left coronary artery (n = 9) and 3 had single ostium. Two patients (2/16, 12.5%) had coronary arteries from left facing sinus (sinus 1) with single ostium. Aortic arch obstruction was associated in 5 patients.

RESULTS

All 5 single sinus coronary arteries with single ostium were reimplanted with the trap-door technique. Of the 11 patients with separate ostia, 8 underwent coronary transfer with the aortocoronary flap technique and 3 with the double-button technique. Two of the 3 patients who underwent the double-button technique required left coronary artery bypass using left subclavian artery free graft as the salvaging procedure. There was one early death (1/16, 6.3%), which occurred during our earlier experience, in a patient who had arch anomaly and intramural left coronary artery. There was no late death. All but one patient had good ventricular function.

CONCLUSIONS

All single sinus coronary artery with single ostium can be transferred with the trap-door technique with excellent results. The aortocoronary flap technique in those with separate ostia with or without intramural left coronary artery may be a good option. However, reimplantation of the intramural left coronary artery using separate coronary buttons should be performed with great care.

Ross procedure for congenital aortic insufficiency and an associated right intramural coronary artery

A 7-year-old boy diagnosed with aortic insufficiency was treated with a Ross procedure and he had an associated right intramural coronary artery. Although preoperative angiocardiography showed that the right and left coronary artery orifices were close together, a right intramural coronary artery could not be diagnosed by transthoracic echocardiography. Intraoperative findings showed that the right coronary artery was intramural for a distance of 7 mm. As a result, a longer single coronary button was harvested and transplanted to the pulmonary autograft. The postoperative course was uneventful; coronary ischemia did not occur and aortic valve function was preserved.

Successful trapdoor technique for two separate coronary ostia in a single aortic sinus in arterial switch operation for complete transposition of the great arteries

Two separate origins of coronary arteries from a single aortic sinus remains a rare but significant congenital anomaly for surgical repair. We experienced a case of a newborn with complete transposition of the great arteries with unusual coronary arteries with two separate ostia positioned close to each other in the same right aortic sinus, and the left coronary artery coursing behind the pulmonary artery. No description of this case in the English literature has been published to our knowledge. Precise anatomical diagnosis was made at operation, and these anomalous coronaries were successfully transferred by the trapdoor technique with delicate adjustment after transfer. Postoperative catheterization and angiogram done 14 months after the arterial switch operation showed no coronary artery stenosis along with normal chamber pressures. The infant is asymptomatic and shows normal development for his age.

Anatomic variability in coronary arterial distribution with regard to the arterial switch procedure

BACKGROUND

We investigated the coronary arterial origins and course and the position of the great arteries in hearts with discordant ventriculoarterial connections. At the same time, we sought to evaluate the practicality of alphanumeric classifications in accounting for surgically relevant features of the coronary arteries.

METHODS AND RESULTS

We studied 200 postmortem hearts, noting the patterns of coronary arterial branching, the vertical and horizontal location of the arterial orifices within the aortic sinuses, the course of the proximal coronary arteries in relation to the aortic wall, and the relations of the great arteries and their respective commissures. All hearts examined had concordant atrioventricular and discordant ventriculoarterial connections. We found 7 of the 8 predicted patterns for sinusal origin of the 3 major coronary arteries and identified 5 different positions of the arterial trunks relative to each other. A correlation was found between less frequent relationships of the arterial trunks and unusual patterns of coronary arterial branching, as well as with mismatch between the valvar commissures.

CONCLUSIONS

The surgically relevant features of the coronary arteries in hearts with discordant ventriculoarterial connections are best described rather than classified. Correlations exist between certain, less frequent relations of the great arteries and unusual patterns of branching of the coronary arteries. The presence of unusual great arterial positions should alert the surgeon to potentially complicated arrangements of the origin and distribution of the coronary arteries.

Myocardial viability assessed by positron emission tomography in infants and children after the arterial switch operation and suspected infarction

OBJECTIVES

The aim of the study was to assess regional glucose metabolism and contractile function by gated positron emission tomography using fluoro-18-deoxyglucose (FDG-PET) in pediatric patients after the arterial switch operation and suspected myocardial infarction.

BACKGROUND

Morbidity and mortality after the arterial switch operation for transposition of the great arteries are often related to impaired coronary function. Justification of high-risk revascularization procedure in infancy requires thorough evaluation of myocardial viability. Although PET is state-of-the-art for evaluation of myocardial viability in adults there are no reports on its impact and feasibility in infants and children.

METHODS

We applied electrocardiogram-triggered FDG-PET for assessment of metabolic and functional status of the myocardium in seven infants and seven children. Glucose metabolism, wall motion and wall thickening were evaluated visually and quantitatively on the basis of parametric 3-D images. Additionally, single-photon emission computed tomography perfusion scan was performed in six children.

RESULTS

In two of seven infants, FDG-PET demonstrated viable myocardium in akinetic or hypokinetic regions corresponding to a coronary artery stenosis or occlusion. Therefore, indication for revascularization was derived from this finding. In six of the seven children, impaired glucose uptake reflecting myocardial scarring was present. Two patients had pathological findings on coronary angiography and signs of ischemia but were not suitable for revascularization.

CONCLUSIONS

Myocardial viability and contractile function can be assessed simultaneously by gated FDG-PET even in infant hearts. This method contributes pertinent information to guide further therapy after the arterial switch operation and suspected myocardial infarction.

Anatomical risk factors for mortality and cardiac morbidity after arterial switch operation

BACKGROUND

The arterial switch operation (ASO) is the treatment of choice for transposition of the great arteries.

METHODS

Anatomical risk factors on mortality and morbidity were analyzed retrospectively in 312 patients who underwent ASO between 1982 and 1997.

RESULTS

Survival was 95%, 92%, and 92% after 30 days, 5, and 10 years, respectively. Operative survival improved after 1990 to 97% (p < 0.001). Risk factors for operative mortality were complex anatomy (p = 0.018), coronary anomalies (p = 0.008), and prolonged bypass time (p < 0.001). Determinants of late mortality were coronary distribution (p = 0.03), position of the great arteries (p = 0.0095), bypass time (p = 0.047), and aortic coarctation (p = 0.046). After a follow-up of 3.6 +/- 2.7 years (0.1 to 14.9 years), 98% had good left ventricle function, 94% were in sinus rhythm, 2.4% had moderate to severe pulmonary stenosis, 0.3% had significant aortic regurgitation, and 1% had coronary stenosis. Freedom from reoperation was 100%, 96%, and 94% after 1, 5, and 10 years, respectively. No preoperative anatomic parameter correlated with long-term morbidity.

CONCLUSIONS

ASO can be performed with low operative mortality (< 5%) and long-term morbidity. Malformations associated with complex transposition of the great arteries influence early and late mortality.

Coronary arterial origins in transposition of the great arteries: factors that affect outcome. A morphological and clinical study

OBJECTIVE

Transfer of the coronary arteries is crucial during the arterial switch operation for transposition, but little attention has been paid to the position of their orifices relative to the valvar sinuses. The objective of this study was to determine the factors which are important for effective transfer and to determine potential surgical significance.

DESIGN

Morphological and clinical study.

SETTING

Two national centres for neonatal cardiac surgery.

PATIENTS

277 patients with transposition of the great arteries. One group comprised 88 necropsy specimens (ages ranging from 17 weeks of fetal life to 17 years old), and the other comprised 189 children undergoing surgery. The coronary artery orifices were inspected relative to the depth of the aortic sinuses (vertical origin), relative to the commissures between the valvar leaflets (radial origin), and their angle of exit from the aortic wall (angle of origin). The data were compared with the surgical results.

RESULTS

In the necropsy specimens, the vertical origin of the arteries was at, or above, the sinutubular junction in 20%, the radial origin was paracommissural in 3%, and the angle of origin was not orthogonal in 7%. Those with high take off and paracommissural origin were all intramural. In the clinical cases, those children with high take off, paracommissural origin or tangential origin had an increased risk at surgery.

CONCLUSIONS

In 20% of hearts, high take off, paracommissural orifice, or tangential origin of coronary arteries is found. This may be recognised preoperatively by echocardiography and may cause technical difficulty in transfer during the arterial switch procedure.

Clinical implications of short-axis aortopulmonary rotation on juxtacommissural origin of the coronary artery in transposition of the great arteries and surgical strategy

BACKGROUND

The relationship of short-axis aortopulmonary rotation (APR) with juxtacommissural origin of the coronary arteries (JOCA) in transposition of the great arteries (TGA) has never been elucidated. The surgical outcome of arterial switch operation (ASO) is influenced by the presence of JOCA.

METHODS

Fifteen patients with TGA who presented to our institution between 1988 and 1995, and 23 cases from the literature, all with documented JOCA and APR, were analyzed. Each coronary arterial type was assigned to one of five patterns, according to similarities of epicardial configuration. All our patients underwent an ASO with various techniques to deal with JOCA.

RESULTS

JOCA near the facing commissure (FC, 35 cases), were more frequent with anterior TGA (29/31, 94%) except types 5cj and 9j that were seen with posterior and right lateral TGA (4/4, 100%); whereas JOCA near the right-hand nonfacing commissure (RNC, 3 cases) were related with posterior TGA. Eta-square analysis showed significant correlation between various JOCA and short axis APR. Thirteen of our cases had JOCA near FC, two near RNC. Five of the former in whom the coronary artery was excised as a single button had a superior trapdoor; using a two-button technique three of the former had a lateral funnel and one of the latter had a medial trapdoor for the JOCA; all survived although on late noncoronary death was noted. In the remaining six cases without augmentation, only one survived (8/1 vs 1/5, p < 0.02).

CONCLUSION

JOCA in TGA was related to short axis APR, generally near FC in anterior TGA (except types 5cj and 9j), and near the RNC in posterior TGA. A superior (lateral) or medial flap, to augment the coronary button for JOCA near FC or RNC is helpful for a successful ASO.

Angiographic evidence of long-axis rotation in addition to short-axis aortopulmonary rotation: its implication in transposition of the great arteries

To assess the pattern of aortic sinus in varied aortopulmonary rotations and its clinical implications, three aortic sinuses at the diastolic phase in true lateral view are identified in 53 angiograms of complete transposition of the great arteries recorded between 1988 and 1993. The patients with the high takeoff of the coronary arteries found at surgery and in the literature were selected for additional investigation. Six regions were defined on the horizontal plane. From left anterior 89 degrees to 61 degrees, the non-facing sinus moved toward the anterior aspect (one patient). From left anterior 60 degrees to left anterior 1 degree, the left-hand sinus moved gradually from an anterior toward a posterior location (two patients). From directly anterior 0 degree to right anterior 59 degrees, the right-hand sinus moved from posterior toward an anterior position (30 patients). From right anterior 60 degrees to right posterior 105 degrees, the non-facing sinus moved posteriorly (20 patients). On approaching directly anterior 0 degree and toward right anterior 60 degrees, the left-hand sinus was the lowest in anterior transposition of the great arteries instead of the non-facing sinus, as in left anterior 90 degrees and in posterior transposition of the great arteries. High takeoff occurred commonly above the lowest left-hand sinus in anterior transposition of the great arteries (2 cases here and 5 in the literature, 100%). In conclusion, aortopulmonary rotations about the short and long axes were both evident on identification of the aortic sinus in various rotations. The aortic sinus did not rotate along the long-axis in anterior transposition of the great arteries, thus making the left-hand sinus, the lowest of this group, vulnerable to the high takeoff of the coronary arteries in anterior transposition of the great arteries.

The coronary arteries in hearts with discordant atrioventricular connections

Gross morphologic study of 14 hearts with congenitally corrected transposition or discordant atrioventricular connections and double-outlet right ventricle or pulmonary atresia disclosed consistently the origins of the coronary arteries from two aortic sinuses. With usual atrial arrangement, the artery arising in sinus 1 (right-hand facing), as seen from the noncoronary aortic sinus, supplied the morphologically right ventricle. Coronary blood supply to the morphologically left ventricle usually came from sinus 2 (left-hand facing), although in two hearts the circumflex branch was a continuation of the artery from sinus 1. The sinus nodal artery arose from the circumflex coronary artery, and histologic studies of two hearts demonstrated that blood supply to the anterior atrioventricular node also came from this vessel. Early branching and entrapment in fat or right ventricular muscle, as well as malalignment of aortic and pulmonary sinuses, occurred frequently. These findings may have implications for coronary arterial transfer in the double switch operation in hearts with discordant atrioventricular connections.

Evolution of coronary artery pattern according to short-axis aortopulmonary rotation: a new categorization for complete transposition of the great arteries

OBJECTIVES

We studied the correlation between coronary artery pattern and aortopulmonary rotation in complete transposition of the great arteries.

BACKGROUND

Classifications of the coronary arteries in complete transposition are puzzling and incomplete.

METHODS

Coronary artery anatomy and relation of the great arteries were identified at angiography, echocardiography, surgical intervention or autopsy in 76 patients with complete transposition from 1988 to 1993. Five main types (type 0 and Shaher types 1,2,4 and 9) and their similar variants of epicardial configuration were categorized into five patterns (O, I, II, IV and IX). In addition, data from 568 cases from published reports were collected for analysis.

RESULTS

As the aorta rotated from a left anterior to a directly anterior location relative to the pulmonary trunk, the left anterior descending coronary artery arose from the left-hand sinus together with the right coronary artery (type 0, one case decreased to no cases); then it gradually shifted to the left to have the same origin as the left circumflex coronary artery from the right-hand sinus (type 1, 10 cases increased to 146, p < 0.0003). When the aorta rotated farther clockwise from directly anterior to right anterior (type 1, 146 cases increased to 235; type 2, 9 cases increased to 50, p < 0.0006) or from right anterior to right lateral (type 1, 235 cases decreased to 6 cases; type 2, 50 cases decreased to 20, p < 0.00000), the left circumflex coronary artery tended to move retropulmonically and originated from the left-hand sinus with the right coronary artery (type 2). When the aorta moved from right anterior to right lateral (type 2, 50 cases decreased to 20; type 4, 13 cases increased to 14, p < 0.031) or from right lateral to right posterior (type 2, 20 cases decreased to 1; type 4, 14 cases increased to 16, p < 0.0003), the right coronary artery shifted to the right-hand sinus anteaortically to join the left anterior descending coronary artery (type 4). Finally, the left anterior descending coronary artery combined with the left circumflex coronary artery (type 9, 12 cases increased to 21, p = 0.407) to become the usual pattern for normally related great arteries. Eta-square analysis showed that the evolution from pattern O to IX was dependent on clockwise aortopulmonary rotation.

CONCLUSIONS

The coronary arteries in complete transposition of the great arteries can be classified into five patterns and their evolution deduced on the basis of aortopulmonary rotation. Dependence of coronary artery type on aortopulmonary rotation made it possible to anticipate the coronary pattern from the relation of the great arteries in transposition.

Coronary arterial anatomy in double-outlet right ventricle with subpulmonary VSD

We have examined 38 hearts with a double-outlet right ventricle with a subpulmonary ventricular septal defect. We divided the hearts into three groups according to the angle between the planes formed between the outlet septum and the remainder of the muscular ventricular septum; namely, at approximately right angles (15 hearts), parallel (11 hearts), and at an acute angle (12 hearts). The coronary arterial pattern corresponding to that seen in the normal heart was present in 11 hearts (73%) of the "right angle" group, in only one heart (8%) of the "acute angle" group, and in none of the "parallel" group. In contrast, the most common pattern in the setting of complete transposition was observed in none, 8%, and 91% of each group, respectively. Other diverse patterns were recognized in the hearts in the acute angle group, and the incidence of abnormal branching was significantly higher in this than in the other groups (p < 0.01). Knowledge of these anatomic variations in the course of the coronary arteries, some of which would cause problems at either definitive repair or reoperation, are essential for those seeking to achieve optimal surgical repair.