Anomalous Origin of Right Pulmonary Artery from the Ascending Aorta–Intraoperative Transesophageal Echocardiography and Surgical Images

A 2-month-old male infant weighing 3.8 kg presented with a history of breathlessness and recurrent respiratory tract infection. Preoperative transthoracic echocardiography revealed that the right pulmonary artery (RPA) was arising from the ascending aorta, (AA) and the main pulmonary artery (MPA) was continuing as the left pulmonary artery (LPA). There was no other structural heart defect and the biventricular systolic function was preserved. The patient was scheduled for the reimplantation of RPA to MPA. In the operation room, after the induction of anesthesia, the heart was examined using a neonatal transesophageal echocardiography (TEE) probe (S8-3t) (IE 33; Philips Medical, Bothell, WA, USA). In the mid-esophageal aortic valve long-axis view, the RPA was seen arising from the posterior wall of AA at about 1.4 cm from the aortic annulus [Figure 1a]. On color Doppler examination, there was increased flow turbulence in the RPA due to high-pressure blood flow from the aorta [Figure 1b and Video S1]. On examination in the mid-esophageal ascending aorta short-axis view, the MPA was dilated and was continuing as LPA [Figure 1c and Video S2]. Sternotomy was performed and the surgical findings were found to be similar to the intraoperative TEE images [Figure 1d]. After adequate systemic heparinization, cardiopulmonary bypass (CPB) was instituted and the heart was arrested in diastole using cardioplegia. The RPA was divided from the AA and directly anastomosed to the MPA [Figure 1e]. The surgical rent on the AA was closed with a pericardial patch. Post-repair TEE showed good flow in both the branch pulmonary arteries with preserved biventricular function [Figure 1f]. The measured size of MPA was 9 mm, RPA was 6 mm, and LPA was 7 mm. The patient was shifted to the intensive care unit with inotropic infusions of milrinone of 0.5 μg/kg/min and norepinephrine of 0.025 μg/kg/min. To manage high pulmonary vascular resistance, a sildenafil infusion of 1.6 mg/kg/day was started. The child was electively ventilated for 2 days. The postoperative period of the child was uneventful.

Figure 1.

(a) Pre-cardiopulmonary bypass transesophageal echocardiographic mid-esophageal aortic valve long-axis view (probe slightly rotated right) showing right pulmonary artery arising from the aorta (b) Pre-cardiopulmonary bypass transesophageal echocardiographic mid-esophageal ascending aorta long-axis view (color Doppler) showing turbulent blood flow from the aorta to the right pulmonary artery (c) Pre-cardiopulmonary bypass transesophageal echocardiographic mid-esophageal ascending aorta short-axis view, showing the main pulmonary artery continuing as left pulmonary artery and right pulmonary artery arising from the aorta (d) Surgical image showing the right pulmonary artery arising from the aorta (e) Post-surgical image showing anastomosis of the right pulmonary artery to the main pulmonary artery (f) Post-cardiopulmonary bypass transesophageal echocardiographic mid-esophageal ascending aorta short-axis view showing good flow in both branch pulmonary arteries. AA = Ascending aorta, Ao = Aorta, LAX = Long axis, AV = Aortic valve, LPA = Left pulmonary artery, LV = Left ventricle, ME = Midesophageal, MPA = Main pulmonary artery, RA = Right atrium, RPA = Right pulmonary artery, RV = Right ventricle, SAX = Short axis, SVC = Superior vena cava, TEE = Transesophageal echocardiography

Anomalous origin of the RPA from the aorta is a rare congenital anomaly, occupying 0.1% of congenital heart diseases.[1] In this case, the left lung was receiving the entire cardiac output of the right ventricle, and the right lung was exposed to pressure and volume overload of high systemic blood flow from the aorta. This may result in a large left to right shunt and both lungs may develop the pulmonary vascular occlusive disease if early surgical repair is not performed.[2] The goal of anesthetic management in these subsets of patients is similar to that in patients with a large left-to-right shunt. During CPB, aortic cannulation should be performed as close to the distal end as possible on the ascending aorta to provide sufficient space for an aortic cross-clamp. Also, the anomalous RPA should be snugged tight before going on CPB; otherwise, it may result in a steal of systemic CPB blood flow. After surgical correction, the afterload to the right ventricle increases as it has to pump against the resistance of both lungs. This may result in acute right ventricular dysfunction in the postoperative period.[3] Pulmonary artery pressure monitoring, use of pulmonary vasodilators, and right ventricular supportive therapy are needed in the early postoperative period. Early surgery, maintenance of good hemodynamic stability, well-effective ventilation, and appropriate intraoperative TEE guidance are extremely important for successful surgical recovery in these subsets of patients with differential lung perfusion.

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The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.