Abstract
Pulmonary artery to the left atrial fistula is a rare anomaly. Two young males presented with effort intolerance and cyanosis and had large pulmonary artery to left atrial fistula from right and left pulmonary artery, respectively. The right-sided fistula was closed with a large duct occluder device in transseptal approach whereas the left-sided fistula was closed with a large muscular ventricular septal device. Complete occlusion and symptomatic relief was achieved in both cases. In the follow up the patients were doing well.
Keywords: Pulmonary artery, Left atrium, Fistula, Cyanosis, Device closure
Learning objective
Pulmonary artery to left atrial communication is a relatively rare entity which requires a high index of suspicion for correct diagnosis. Central cyanosis, effort intolerance in the absence of intracardiac right to left shunt is the clue. The communication can be closed successfully by transcatheter approach or surgically.
Introduction
Pulmonary artery (PA) to left atrial (LA) communication is a unique and rare disease. It usually presents in adult age with symptoms of exertional dyspnea along with cyanosis although in newborns it can present with heart failure. We describe our experience with two cases of percutaneous closure of large pulmonary artery to the left atrial fistula.
Case one
The first patient, a 27-year-old male weighing 57 kg presented with symptoms of Class II effort intolerance and cyanosis. The oxygen saturation was 78%, heart sounds were normal and a grade 2/6 systolic murmur was audible in the second left intercostal space. Chest X- ray showed dilated right parahilar region (Fig. 1a). The echocardiogram showed normal intracardiac anatomy and good cardiac function. Contrast echocardiogram showed dense contrast filling of left atrium (LA) via right lower pulmonary vein after three cardiac beats in apical and parasternal short-axis view suggestive of right to left shunt. Computed tomographic pulmonary artery (CT PA) angiogram showed the right pulmonary artery (RPA) to LA fistula with aneurysmal sac (Fig. 1b,c). The CT angiogram was analyzed and discussed in detail with the expert radiologist to plan the intervention. The narrowest part between distal part of branch PA and the aneurysmal sac was selected for occlusion. The lower pulmonary vein was seen not coming on the way to get occluded by the proposed device. The patient was taken for cardiac catheterization. The PA systolic pressure was found normal during catheterization. The angiogram in frontal and lateral projection showed an aneurysmally dilated RPA to LA fistula with a tortuous tract (Fig. 2a,b, Movie1a,b). The fistula was closed by a trans-septal approach. A Terumo wire (Terumo, Tokyo, Japan) was taken across the fistula from the RPA and snared from the LA thereby making a veno-venous loop. A 10 F Mullin sheath was introduced in the LA and negotiated in the fistulous tract and parked in the RPA. An 18-20 mm “HEART” duct occluder (Lifetech Scientific, Shenzhen, China) was taken through the long sheath and deployed in the fistula. Post deployment angiogram in frontal and lateral view showed complete occlusion of the fistula (Fig. 2c,d). The arterial oxygen saturation (SpO2) increased from 78% to 98%. The patient was discharged on warfarin with target international normalized ratio 1.5-2 and aspirin. There was no residual flow in the fistula and no evidence of any clot formation on echocardiogram. He was doing well in the midterm follow up.
Fig. 1.
(a) Chest X-ray showed dilated right parahilar region (multiple arrow). Computed tomographic pulmonary artery angiogram in antero-posterior (b) and lateral view (c) showed right pulmonary artery to left atrial fistula with aneurysmal sac (arrow).
Fig. 2.
The angiogram in frontal (a) and lateral (b) projection showed an aneurysmally dilated right pulmonary artery to left atrial fistula with a tortuous tract. Post deployment angiogram in frontal (c) and lateral (d) view showed complete occlusion of the fistula by the duct occluder marked by a notched arrow.
Second case
The second patient was a 22-year-old male weighing 34 kg who presented with effort intolerance and cyanosis (SpO2 64%). He had dextrocardia (Fig. 3a), normally split second heart sound and no significant murmur. In echocardiogram, there was significant left-sided chamber dilatation and patent foramen ovale with left to right shunt. Contrast echocardiogram revealed dense contrast filling of LA from left-sided pulmonary veins. CTPA angiogram revealed an aneurysmal left PA to the left atrial fistula (Fig. 3b,c). The pulmonary CT was three-dimensionally reconstructed and analyzed to locate the point of narrowing between the left PA and the abnormal aneurysm. The pulmonary vein pathway was away from the proposed closure site without any possibility of obstruction. Angiogram showed an aneurysmal left PA to LA connection with rapid runoff (Fig. 4a, Movie 2a). The LA was entered via the left PA through the fistula with the help of a 4 F right Judkins catheter and Terumo wire. The Terumo wire was exchanged with 0.035 Amplatz superstiff wire. A 12 F braided long sheath was taken over an Amplatz superstiff wire to the LA. A 24-mm muscular ventricular septal device (Lifetech Scientific) was deployed under fluoroscopic guidance. Post occlusion angiogram showed complete occlusion of the anomalous left PA-LA fistula (Fig. 4b, Movie 2b). The saturation improved from 64% to 98% on the table. He was discharged with aspirin and warfarin and is doing well in follow up.
Fig. 3.
(a) Chest X-ray in frontal view showed dextrocardia and prominent left paracardiac shadow. Computed tomographic pulmonary artery angiogram (b) and three-dimensional reconstruction (c) revealed an aneurysmal left pulmonary artery to the left atrial fistula (arrow).
Fig. 4.
(a) Angiogram in anteroposterior view showed an aneurysmal left pulmonary artery (LPA) to left atrial (LA) connection (arrow) with rapid runoff. (b) Post occlusion angiogram showed complete occlusion of the anomalous LPA-LA fistula with large device (notched arrow).
Discussion
The PA to the LA fistula is a rare cause of central cyanosis. Embryologically, incomplete degeneration of septum between the arterial and venous plexus of the pulmonary vascular bed or defective capillary loop leads to formation of thin-walled sacs resulting in formation of pulmonary arteriovenous fistulas. A pulmonary vein connected to this fistula is absorbed into LA, resulting in a PA–LA fistula. Around 100 cases of PA-to-LA fistula have been reported with male dominance. Right-sided fistula are much more common than left-side, only a few cases of left PA-to-LA fistula have been reported. The magnitude of right to left shunt and the age at presentation determine the clinical features. The complication of an unoperated fistula can be embolic manifestations, endarteritis, hyperviscosity symptoms, and even fatal rupture [1], [2], [3].
The young and adult population presents with effort intolerance, cyanosis whereas in neonatal age heart failure and central cyanosis dominate. High index of suspicion is required for diagnosis. Chest X-ray may reveal abnormal para cardiac shadow. Contrast echocardiography clinches the diagnosis by showing appearance of contrast to left-sided cardiac chambers after three beats in the absence of intracardiac shunt [4], [5]. PA to LA fistula can be delineated by CT angiography or magnetic resonance angiography. Detailed analysis of the fistula anatomy and discussion with the radiologist is the key for successful closure. The idea should be closing the fistula by transcatheter way in the point of narrowing without obstructing pulmonary venous inflow. The percutaneous closure can be done with coils or different types of occluders such as duct occluder, muscular ventricular septal defect device, septal occlude, etc. Trans-atrial septal approach by creating a wire loop and deploying the occluder device from the PA side has the advantage of placing the bigger disk of the Amplatzer duct occluder. Septal puncture can be done in patients without interatrial communication [6]. Surgical ligation can also be done although it is less preferable [7].
Disclosures
No relationship with industry
Funding
Nil No funding or financial help involved
Ethical Issue
None
Declaration of Competing Interest
None
Acknowledgments
None to declare
Footnotes
Supplementary material related to this article can be found, in the online version, at doi:https://doi.org/10.1016/j.jccase.2020.05.017.
Appendix A. Supplementary data
The following are Supplementary data to this article:
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