Perioperative Identification and ligation of MAPCAs under TEE guidance: Case series of seven patients

Vishnu Datt^1*, Rachna Wadhwa¹, Suman Keshav¹, Shraddha Malik¹, Saket Aggarwa^l,2 Ehtesham Naqvi², MA Geelani²

¹Ex- Director Professor and HOD cardiac Anesthesia, GIPMER, New Delhi, Professor and HOD of Anesthesiology SGT, Medical College, Budhia, Gurugram, Haryana

²Departments of Cardiac Anesthesia and cardiothoracic and vascular surgery, GIPMER, New Delhi, and Anesthesiology SGT, Medical College, Budhia, Gurugram Haryana, India

*Corresponding author: Dr Vishnu Datt. Ex- Director Professor & HOD cardiac Anesthesia, GIPMER, New Delhi Professor and HOD of Anesthesiology, SGT, Medical College, Budhia, Gurugram, Haryana

Received: 30 March 2026; Accepted: 13 April 2026; Published: 06 May 2026

Introduction

Patent ductus arteriosus and MAPCAs are additional sources of pulmonary blood flow and influence the hypoxic symptoms of TOF and other congenital cyanotic lesions. TOF may be associated with MAPCAs in less than 5% of cases [1]. However, the incidence of MAPCAs increases to 20-25% in patients oof TOF with pulmonary atresia and presents one of the greatest challenges during total corrective surgery [2]. MAPCAS may play a big role in establishing the pulmonary blood flow and arterial oxygen saturation in severe cyanotic congenital cardiac anomalies, and largest MAPCA can be used for antilocalization surgery to reconstruct the pulmonary artery as a single source of pulmonary blood flow in TOF with pulmonary atresia [3]. Occasionally, the pulmonary blood flow through the MAPCAs can be excessive, producing high So₂, CHF, and possible PVR changes caused by over circulation and high-pressure flow into the PAs. In addition, the MAPCAS can undergo spontaneous rupture resulting in life threatening mediastinal or endotracheal bleeding [4]. The perioperative interruption of the large collateral vessels is often performed either by fluoroscopy-guided embolization in the preoperative or postoperative period [4,5]. Another option is to ligate the collaterals during the surgery [1,6]. Perioperative coil embolization under fluoroscopic guidance either in the preoperative or postoperative period remains an ideal initial management in the patients of TOF with MAPCAs. In addition, MAPCAs ligation during the surgery is another option. However, preoperative coiling of MAPCAs is not feasible in patients with severe desaturation and refractory recurrent Tet spells. Echocardiography, diagnostic cardiac catheterization, CT angiography, and cardiac MRI can all be used to delineate the TOF anatomy and MAPCAS [5-8]. In this study, we describe seven cases of MAPCAs diagnosis and ligation under the transesophageal echocardiography (TEE)-guidance in patients undergoing various cardiac surgical procedures.

Table 1: Describes the details of the 7 patients as age, diagnosis, TTE findings, surgical procedures, and in addition the diagnosis and ligations of MAPCAS before and after the cardiac surgical procedure under the TEE guidance. TEE also delineates the various sites of the MAPCAs in different cardiac lesions.

Cases presentations

Case 1: 5 yrs- male, weighing 15 kg presented with cyanosis, chest pain and palpitations for one year of age. He was diagnosed with tricuspid atresia (TA) with multiple VSDs and large OP ASD. Cardiac catheterization revealed no major MAPCAs. He was scheduled for Glenn procedure (Video.3) After induction of anesthesia, a pediatric -TEE probe (Size- 11x8mm, Model- GE VIVID S60 N) was inserted and a comprehensive cardiac examination was performed to confirm the preoperative TTE findings. In addition, 2-3. MAPCAs were detected arising from descending thoracic aorta (DTA). At the upper -DTA level, 2-3 MAPCAs of 1-3 mm originating from the anterior wall were found on gentle counterclockwise rotation and zooming of the probe, and the same number were ligated after the Glenn procedure.

Case 2: A 15 yrs female, weighing 30 kg presented with cyanosis, palpitations and dyspnea since childhood. TTE revealed TA, hypoplastic RV,3cm OS ASD with right to left shunt, small PM VSD with a pressure gradient of 90mmHg and mild PS. CT revealed MAPCAs arising from left subclavian artery and distal aortic arch. She was scheduled for the bidirectional Glenn procedure. After anesthesia induction, an adult -TEE probe was inserted, and a comprehensive cardiac examination was performed using an ultrasound system (Model- GE VIVID S60 N) to confirm her preoperative TTE findings. In addition, on zooming the DTA view at 0 and 90 degrees, multiple MAPCAs were detected arising from medial aspect of the descending thoracic aorta (Video1). The color- Doppler confirmed their coursing towards and away from the probe. The MAPCAs were ligated via trans-sternotomy under the TEE guidance before the Glenn procedure.

Video 1: Mid- esophageal, DTA SAX view of TEE: Color Doppler examination reveals multiple tortuous vessels as MAPCAS arising from the medial wall of the DTA. The blue and red color confirms the flow away and towards the transducer and depicts distal and proximal aorta.

DTA- descending thoracic aorta, SAX- short axis, TEE- trans-esophageal echocardiography, MAPCAs- major aorta-pulmonary collateral arteries.

Case 3: A 1.5-year-old male, weighing 8 kg, child presented with cyanosis since birth. He was diagnosed as TOF. TTE revealed a large subaortic VSD, infundibular and valvular PS, severe aortic override >90%. Cardiac catheterization was not performed. After anesthesia induction, a pediatric TEE probe (Size- 11x8mm, Model- GE VIVID S60 N) was inserted and a comprehensive cardiac examination was a performed, which also revealed a 1.9cm, VSD with bidirectional shunt, a PFO with bidirectional, large PDA, LVIDD 1.6cm, posterior wall thickness of 0.4cm, LV mass of 14.81 Gm, McGoon’s ratio 0.6, and EF of 65%. In addition, multiple MAPCAs were detected arising from the descending aorta.  At the proximal -DTA level, several MAPCAs of different sizes, originating from the medial wall of the DA and traversing in multiple directions, and showing blood flow towards and away from the probe were detected on zooming and gentle counterclockwise rotation of the probe. All the MAPCAs were confirmed and ligated before establishing CPB by the operating surgeon via same mid-sternotomy incision used for Glenn procedure, to ameliorate the deleterious effects of MAPCAs during CPB. Color- flow Doppler TEE examination also confirmed the absence of the flow, and the optimum ligation of the multiple MAPCAs. (Video 3).

Video 3: Upper -Esophageal, Ascending Aorta short Axis view of TEE revealed a laminar flow (blue color) in the RPA as an unobstructed and functional Glenn, depicted above the ascending aorta. RPA-right pulmonary artery.

Case 4: A 20 Years - 40 kg male presented with dyspnea on exertion, and chest pain. He was diagnosed as TOF. TTE revealed 2cm subaortic VSD with R-L shunt, dilated RA, severe infundibular PS, < 50% aortic override. CT also confirmed the diagnosis of the TOF, and in addition also revealed multiple MAPCAs. He was scheduled to undergo total correction for TOF. After induction of anesthesia, an adult TEE probe was inserted for comprehensive cardiac examination. TEE evaluation also confirmed the findings suggestive of TOF. In addition, TEE examination on 2-D and color doppler examination of DTA view (0 and 90 degrees) also revealed multiple MAPCAs originating from the anterior and posterior wall of the descending aorta, and several of these were ligated via sternotomy under the TEE guidance before the total correction of the TOF.

Case 5: A 13-year male weighing 37 kg presented with DOE, cyanotic spells. TTE revealed subaortic VSD with a gradient of 76 mmHg, infundibular and valvular PS, hypoplastic PA, LV -15 Gm, < 50% aortic override suggestive a diagnosis of TOF. CT revealed MAPCAs arising from the descending aorta. The patient was operated on for the Glenn procedure. TEE examination also confirmed poor LV with 23 Gm mass and in addition multiple MAPCAs originating from the posterior wall of the descending aorta and distal aortic arch and traversing towards and away from the probe were also revealed and ligated under the TEE guidance before the Glenn procedure via the left thoracotomy (Video 4).

Video 4: The Aortic arch LAX view of the aortic arch of TEE: the color doppler depicts multiple MAPCAS from the anterior and posterior wall of the distal aortic arch.

Case 6: 1.5 yrs, 10 kg male child presented with dyspnea and repeated chest infections for 3 months of age. TTE revealed a large peri membranous VSD (1.4 cm) with a pressure gradient of 33 mmHg and left to right shunt and muscle bundles in the RVOT, and normal biventricular functions. The patient was posted for excision of RVOT muscle bundles and the VSD patch repair. After induction of anesthesia the pediatric TEE probe was inserted. The TEE examination also confirmed the large peri membranous VSD and muscle bundles in the RVOT. In addition, it also revealed two big MAPCAs arising from the posterior wall of the descending aorta, and color Doppler examination showed the blood flow towards the probe. Both MAPCAs were ligated via the trans -sternotomy route under the TEE guidance after the intracardiac repair.

Case 7: 18 yrs, 40 Kg male presented with cyanosis and dyspnea on exertion’s revealed large S/A VSD with R-L shunt, more than 50% aortic over ride, infundibular and valvular PS, CT also confirmed S/A VSD20.1 mm, RA and RV dilated, dilated aortic root(34.7 mm) and ascending aorta(35.9mm) with aortic override, infundibular stenosis and stenosis at LPA origin. In addition, multiple dilated MAPCAs from descending thoracic aorta traveling tortuous course in the mediastinum supplying hilum pulmonary circulation was confirmed. Direct VSD closure, RVOT muscle bundle excision, pericardial patch augmentation of RVOT were performed under standard moderate hypothermic CPB. Multiple MAPCAs with tortuous course noted arising from lateral and posterior wall of descending aorta with flow towards and away from probe were confirmed by TEE. All except one deep seated MAPCA arising from posterior wall ligated intra-operatively.

Discussion

The arteries originating from the aorta or its branches supplying the pulmonary blood flow for a segment or a lobe of the lung without any connection to the central pulmonary arteries are defined as MAPCAs and develop spontaneously providing additional blood flow to the lungs as the major contributors. Indeed, MAPCAs are frequently encountered in cyanotic cardiac anomalies such as severe TOF with PA, tricuspid atresia (TA), single ventricle pathology, d- TGA, DORV, truncus arteriosus etc. [1,9] TOF patients with significant RVOT obstruction or pulmonary atresia may require some additional sources of pulmonary blood flow from PDA or MAPCAs for maintaining the arterial oxygen saturation, and frequently MAPCAs serve as the main source of pulmonary flow.[10] At times, MAPCAs serve as the primary, often sole, source of blood supply to the lungs when the native pulmonary arteries are severely hypoplastic or absent. MAPCAs are rare, and present in 4–10 per 10,000 live births and 2–3% of all CHDs. They are commonly associated with PA/VSD (50–70%), and 5–10% of TOF. Incidence of MAPCAs increased to 20% to 25% of patients with TOF with pulmonary atresia.[11] In the presented cases series, the MAPCAs have been reported in patients of TOF with PS and PA (4cases), and tricuspid atresia (2 cases) and VSD with PS (1 case). Although the precise mechanisms that lead to the development of the MAPCAs are incompletely understood. However, chronic hypoxia, high hemoglobin levels, diminished global or regional pulmonary blood flow and non-pulsatile flow in the pulmonary arteries may contribute for the development of MAPCAs in these patients [1]. The MAPCAs most frequently arise from DTA and aortic arch, but can also originate from the ascending aorta, head and neck vessels (most commonly the subclavian artery), abdominal aorta and even from the coronary arteries or from the infra-diaphragmatic arteries.[12,13] In the presented case series, The common sites of MAPCAs in TOF were posterior and anterior wall of DTA, in TA with VSD the site was anterior and medial wall of DTA, and in one case they were also arising from the left subclavian artery in addition to DTA, in VSD with PS the origin was from posterior wall. All the diagnosed MAPCAs were ligated before Glenn or total correction in 5 patients using same mid-sternotomy in 3 patients, and left thoracotomy in 2 patients. In 2 cases of TA with VSD, MAPCAs were ligated after cardiac repair using left thoracotomy On radiological assessment, These have been classified as [1] single‐supply (MAPCA serves as the only source of blood flow to the lung segments), with no connection to a central PA, (2) isolated supply to central PAs (the only MAPCA connecting to the central PAs; (3) dual‐supply (1 of ≥2 MAPCAs connecting to the central PAs); or (4) mixed‐supply (≥1 single-supply and ≥1 dual‐supply branches) [12]. MAPCAs may also act as a dual supply, meaning that the central pulmonary arteries arborize normally, with no lung segments receiving blood flow solely from a MAPCA without connection to the central PA system. The pulmonary blood flow through the MAPCAs can be excessive, causing variable clinical presentation, producing high SaO2, CHF, and possible PVR changes caused by over circulation and high-pressure flow into the pulmonary arteries.[14]

The evaluation of TOF with PA and MAPCAs should include chest radiography, magnetic resonance imaging (MRI), and multidetector computed tomography (MDCT) scanning. 2-D echocardiography with color flow and pulse wave Doppler is the most important tool in the diagnosis of tetralogy of Fallot with pulmonary atresia. Color-flow imaging may help to identify sources of pulmonary artery blood flow, including the PDA and MAPCAs. A systematic approach is recommended to ensure visualization of all the zones of the descending thoracic aorta (DTA). A common method is to begin the examination after obtaining the ME 4-chamber view and turning the probe to the left until the descending aorta is seen in SAX at 0 to 15 degrees. From here, the transducer depth is decreased to 6 to 8 cm, and the probe is withdrawn or advanced, following the course of aorta. If collaterals are suspected, echocardiography alone is inadequate for complete delineation of pulmonary blood flow, and further imaging by MRI or angiography is recommended, as viewing them could be difficult at times due to their unpredictable site of origin and course in the mediastinum [5-8]. MRI and MDCT may be used as a non-invasive method and provide excellent delineation of the pulmonary arterial circulation and their MAPCAs. Cardiac catheterization with angiography is recommended not only for delineation of TOF pathology to facilitate surgical planning but also the presence MAPCAs that may need to be either ligated or incorporated into the repair. Traditional angiography remains gold standard for anatomic delineation of MAPCAs and central PAs, and cardiac catheterization is always performed in cases of unclear distribution. But this is not available to all the TOF patients. Preoperative cardiac catheterization evaluation and MAPCAs ligation is limited in patients with very low arterial oxygen saturation and refractory recurrent Tet spells. This is essential for mapping the anatomy, identifying connections between the MAPCAs and the pulmonary arteries, assessing the presence of narrowing (stenosis), and measuring blood pressure within the collaterals before the cardiac surgery. However, many a times either these facilities are unavailable or children are unsuitable due to poor hemodynamic such as uncompensated heart failure or profound cyanosis requiring immediate surgery. In such scenarios, it may be feasible to detect the MAPCAs on preoperative transthoracic echocardiography (TTE), although imaging them could be difficult at times due to their unpredictable site of origin and course in the mediastinum. In this study, we describe seven cases of MAPCAs diagnosis and ligation under the transesophageal echocardiography (TEE)-guidance in patients undergoing various cardiac surgeries. Differential diagnosis of MAPCA on echocardiography includes PDA and posterior intercostal arteries (PICA), which may arise from the distal aortic arch or DTA. The MAPCA should be differentiated from a PDA based on number, size, origin, and course. multiple vessels having similar Doppler flow characteristics are invariably aortopulmonary collateral arteries, which must be differentiated from the PDA. The color Doppler and spectral Doppler examination of a PDA reveals turbulent PDA jet with marked spectral dispersion in systole and diastole (throughout the cardiac cycle) along the anterolateral wall of the main PA probably because of the anatomic arrangement [15,16].

Free flowing MAPCAs have several detrimental effects during CPB, such as a significant systemic to pulmonary shunt causing flooding of the surgical field and interfering the surgery, increased blood return in the CPB circuit, stealing from the cerebral circulation, and persistent low perfusion pressure, reduces effective systemic blood flow or even life threatening mediastinal or endotracheal bleeding due to spontaneous rupture [4,17,18]. The presence of MAPCAs is a significant factor associated with late mortality following cardiac corrective surgery [19]. Thus, MAPCAs have a great impact on CPB management; a bypass flow index of 2.4 L/min/m (2) may not be sufficient, and the maximum requirement of bypass flow index may be 3.2 L/min/m (2) or more in this patient population to maintain the tissue perfusion and normal lactate levels. MAPCAs may contribute low output throughout surgery which can lead to cerebral anoxia and renal hypoperfusion and devastating postoperative sequalae [17]. MAPCAs should be occult included in the cardiac catheterization lab. or should be ligated via thoracotomy before initiation of CPB to avoid the generalized tissue hypoperfusion particularly of the brain. This is the most effective method for preventing a dangerous steal from systemic circulation during CPB. It will also accelerate postoperative recovery [20,21]. Contrary, the MAPCAS may play a big role in establishing the pulmonary blood flow and arterial oxygen saturation, by utilizing largest MAPCA for antilocalization surgery to reconstruct the pulmonary artery in TOF with pulmonary atresia [3]. Lung reperfusion injury in the setting of antilocalization surgery has been estimated in the previous studies at 65% [22]. It is not always possible to perform cardiac catheterization and coil embolization of MAPCAs in a TOF with severe pulmonary artery atresia, risking precipitation of very low arterial oxygen saturation and recurrent refractory Tet spell after coil embolization [23]. In this case series, the MAPCA ligation could not be performed in the preoperative period due to persistent low oxygen saturation and patients were exhibiting repeated Tet spells. However, perioperative TEE evaluation diagnosed MAPCAs commonly originating from the proximal descending aorta or aortic arch and successfully ligated via mid-sternotomy before establishing the CPB or post repair. In addition to the TTE values, the TEE findings also confirmed inoperability for total TOF correction in five patients, and the Glenn procedures were performed as LV and RV were borderline, LV mass was inadequate and inadequate  Mc Goon ratio i.e. 0.5-0.8, (normal average 2.1), a ratio below 0.8 is deemed inadequate for complete repair of pulmonary atresia cases with TOF anatomy (TOF/PA).[24]

Conclusions All patients with significant MAPCAs should undergo coil embolization prior to total correction. However, in patients with TOF/ PA/ MAPCAs and severe hypoxemia due to refractory recurrent Tet spells, preoperative cardiac catheterization and coil embolization is unsafe and risking desaturation and morbidity and mortality. In such a high-risk patient, the MAPCAs can be successfully identified and confirmed or first time  detected by intraoperative TEE. These can be surgically ligated before initiation of CPB, or after coming off bypass via trans-sternotomy or thoracotomy route under the TEE guidance. Surgical ligation of MAPCAs under the TEE guidance is safe, easy, and effective, and prevents the devastating complications of MAPCAs on CPB as well as postoperatively.

Source of funding: Nil

Conflict of interest: Authors declare no conflict of interest

Declaration: All authors were involved in the patient’s management and preparation of the manuscript.

References

1. Sadiq N, Ullah M, Mahmoud A, et al. Perioperative Major Aortopulmonary Collateral Arteries (MAPCAs) Coiling in Tetralogy of Fallot Patients Undergoing for Total Correction. J Cardio Curr Res 3 (2015): e00123.
2. Marelli AJ, Mackie AS, Ionescu-Ittu R, et al. congenital heart disease in general population; Changing prevalence and age distribution. Circulation 115 (2007): 163-172.
3. Margetson T D, CCP, FPP, Sleasman J, CCP, FFP, Kollmann S, et al. Perfusion Methods and Modifications to the Cardiopulmonary Bypass Circuit for Midline Antilocalization Procedures. J Extra Corpora Technol 51 (2019): 147-152.
4. Neeti Makhija, Rohan Magoon, Minati Choudhary, et al. Bleeding in the lung complicates a routine intracardiac repair: What went wrong. Annals of cardiac Anest 21 (2018): 78-81.
5. Sanjay K. Prasad, Nikolaos Soukias, Timothy Hornung, et al. Role of Magnetic Resonance Angiography in the Diagnosis of Major Aortopulmonary Collateral Arteries and Partial Anomalous Pulmonary Venous Drainage. Circulation 109 (2004) :207–214.
6. Geva T, Greil GF, Marshall AC, et al. Gadolinium-enhanced 3-dimensional magnetic resonance angiography of pulmonary blood supply in patients with complex pulmonary stenosis or atresia: comparison with x-ray angiography. Circulation 106 (2002):473-478.
7. Bernardes RJ, Marchiori E, Bernardes PM, et al. A comparison of magnetic resonance angiography with conventional angiography in the diagnosis of tetralogy of Fallot. Cardio Young.16 (2006): 281-288.
8. Rajeshkannan R, Moorthy S, Sreekumar KP, et al. Role of 64-MDCT in evaluation of pulmonary atresia with ventricular septal defect. AJR Am J Roentgen 194 (2010): 110-118.
9. Hannah S. Kim, R. Mark Grady, Shabana Shahanavaz, "Isolated Major Aortopulmonary Collateral as the Sole Pulmonary Blood Supply to an Entire Lung Segment", Case Reports in Cardiology 3 (2017): 1-3.
10. Moll JN, Santos MA, Drumond C, et al. Improved visualization of aortopulmonary collateral arteries by abdominal aortic compression during angiography. Circulation 65 (1982): 953-955.
11. Bauser-Heaton H, Borquez A, Han B, et al. Programmatic Approach to Management of Tetralogy of Fallot with Major Aortopulmonary Collateral Arteries. A 15-Year Experience With 458 Patients. Circulation: Cardiovascular Interventions 10 (2017): e004952.
12. Gregory Adamson T, McElhinney Doff B, Yulin Zhang, et al. Angiographic Anatomy of Major Aortopulmonary Collateral Arteries and Association with Early Surgical Outcomes in Tetralogy of Fallot. Journal of the American Heart Association 9 (2020): e017981.
13. Quinonez ZA, Downey L, Abbasi RK, et al. Anesthetic management during surgery for tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral arteries. World J Pediatric Congenic Heart Surg 9 (2018): 236–241.
14. Dean Andropauses MD, MHCMEr in Gottlieb. Chapter 3 - Congenital Heart Disease.in: Anesthesia and Uncommon Diseases (6thed) 26 (2013): 318-326.
15. Liao PK, Su WI, Hung JS. Doppler echocardiographic flow characteristics of isolated patent ductus arteriosus: Better delineation by Doppler color flow mapping. J Am Coll Cardio 12(1988): 1285-1291.
16. Chugh R, Salem MM. Echocardiography for patent ductus arteriosus including closure in adults. Echocardiography 32 (2015): 125– 139.
17. Liu YL, Shen XD, Li SJ, et al. (2006) An integral approach for cyanotic congenital heart disease with major aortopulmonary collateral arteries. Zhonghua Yi Xue Za Zhi 86 (2026): 228-231.
18. Miyazaki, Noszka O, Hayakawa S. Musudan death due to rupture of major aortopulmonary collateral arteries in a patient with tetralogy of Fallot and pulmonary atresia. Emge Radiol 8 (2001): 293-296.
19. Cho JM, Puga FJ, Danielson GK, et al. Early and long-term results of the surgical treatment of tetralogy of Fallot with pulmonary atresia, with or without major aortopulmonary collateral arteries. The Journal of Thoracic and Cardiovascular Surgery 124 (2002): 70-81.
20. Fujii Y, Kotani Y, Kawabata T, et al. The benefits of high-flow management in children with pulmonary atresia. Arif Organs 33 (2009): 888-895.
21. Isitt RW, Robertson DA, Crook RM, et al. Tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral vessels. Perfusion 29 (2014): 567-570.
22. Maskati a SA, Feinstein JA, Newman B, et al. Pulmonary reperfusion injury after the antilocalization procedure for tetralogy of Fallot, pulmonary atresia, and major aortopulmonary collateral arteries. J Thoric Cardiovasc Surg 144 (2012):184–189.
23. Balaguru D, Dilawar M. Pulmonary atresia with ventricular septal defect: systematic review. Heart Views 8 (2007): 52–56.
24. Balaguru D, Dilawar M. Pulmonary atresia with ventricular septal defect: systematic review. Heart Views. 2007;8:52–6.