Follow-up of Percutaneous Transcatheter Closure of Pulmonary Arteriovenous Fistulas
Pulmonary arteriovenous fistulas (PAVFs) are abnormal vascular connections that bypass the pulmonary capillary bed, creating a direct right-to-left shunt. This condition can lead to a range of clinical manifestations, from asymptomatic cases to severe symptoms such as dyspnea on exertion, fatigue, cyanosis, and neurological complications. PAVFs are often associated with hereditary hemorrhagic telangiectasia (HHT) and congenital heart disease. The primary goal of treatment, whether through transcatheter techniques or surgery, is to reduce or eliminate the abnormal shunt and prevent severe complications. With advancements in medical technology, the indications for interventional closure of PAVFs have expanded. However, there is still a lack of comprehensive data on the efficacy and safety of transcatheter closure of PAVFs.
This retrospective study included 13 patients (7 males, 6 females) aged 1 to 59 years who were diagnosed with PAVF and underwent heart catheterization and/or transcatheter closure at the Guangdong Cardiovascular Institute in China between April 2006 and September 2016. All patients were diagnosed using contrast-enhanced cardiac computed tomography. The study reviewed case records, test results, and data collected via telephone follow-up. Written informed consent was obtained from all patients or their guardians, and the study protocol adhered to the Declaration of Helsinki and was approved by the Institutional Review Board of Guangdong General Hospital.
Before the procedure, all patients underwent a complete examination. Those who underwent interventional procedures under general anesthesia received an intravenous heparin bolus (100 U/kg). Access was obtained through femoral venous or femoral arterial catheters. After heart catheterization, selective left or/and right pulmonary artery angiography was performed based on preoperative examinations to determine the anatomy, location, type, feeding artery, and drainage site of the PAVF. In cases where diffuse fistulas could not be confirmed by selective angiography, agitated saline with air was injected into the specific pulmonary artery under transesophageal echocardiography monitoring.
If the PAVF was not diffuse and met the criteria for transcatheter occlusion, the procedure was attempted. A 5F or 6F multipurpose catheter or a right coronary guidewire and a 0.032 inch x 260 mm guidewire and a 0.035 inch x 260 mm super stiff straight tip were used to access the feeding artery and/or fistula, and a delivery system was created. Occlusion devices, such as coils, an Amplatzer vascular plug, or a Leftech vascular plug, were deployed through a delivery sheath. Post-deployment, oxygen saturation, 12-lead electrocardiography, blood pressure, and clinical manifestations were monitored for 15 to 20 minutes. Selective pulmonary artery angiography was performed to evaluate and confirm the blood supply of nearby lung tissue. Acute success of transcatheter occlusion was defined as an increase in postoperative arterial oxygen saturation to over 90%.
The choice of occlusion devices was based on the size and anatomic features of the feeding artery. Devices used included the Leftech vascular plug (LVP), Amplatzer vascular plug I/II, and Cook coils. The age of the patients at the time of the procedure ranged from 1 to 55 years, with a median of 25 years. Their body weight ranged from 9 kg to 72 kg. Five patients were asymptomatic, seven had cyanosis and polypnea, and one was hospitalized due to hemoptysis. Based on clinical symptoms and family history, three patients were diagnosed with HHT before or during the follow-up.
Electrocardiographic examination before the procedure showed left ventricular super voltage in two patients, Wolff-Parkinson-White syndrome (WPW) type B in one patient, frequent premature ventricular beats in one patient, and sinus tachycardia in one patient. Echocardiography revealed left atrial and left ventricular dilation in one patient, left ventricular dilation in three patients, and patent foramen ovale (PFO) in one patient. Thirteen patients underwent heart catheterization, and 10 were successfully treated by transcatheter occlusion. Three patients were not eligible for transcatheter occlusion due to diffuse or multi-lobar lesions.
The pulmonary to systemic blood flow ratio (Qp/Qs) was calculated based on oxygen saturation at different locations to estimate left-to-right shunting. The average Qp/Qs ratio was 1.72 ± 0.20 (range: 1.23:1 to 2.13:1). The anatomical morphology of the PAVFs was fully presented before occlusion by selective and repeated angiography. Four patients had a single feeding artery, five had double feeding arteries, one had triple feeding arteries, one had multiple feeding arteries, and two had diffuse fistulas. The mean diameter of the feeding arteries was 4.99 ± 1.92 mm (range: 2.7 mm to 8.1 mm).
Two patients underwent re-intervention for occlusion of new-onset PAVF, one patient underwent lobectomy for recanalization of the PAVF, and three patients with diffuse or multiple fistulas, who were not eligible for interventional or surgical procedures, suffered severe pulmonary hypertension (PH), heart failure, and even death during follow-up.
The occluder devices used in this study were analyzed retrospectively. The LVP was deployed in eight cases, coils in two procedures, the Amplatzer vascular plug II (AVP II) in two procedures, and the AVP I in two procedures. Four patients were treated successfully with one occluder, six patients required more than one occluder, and two patients had more than one type of device implanted. There were no serious complications such as thrombopoiesis, fistula rupture, or occluder detachment during the procedure and perioperative period.
All 13 patients were available for follow-up after heart catheterization and/or transcatheter occlusion, with a mean follow-up period of 7.1 ± 2.7 years (range: 3–12 years). Three patients presented with cyanosis after the first transcatheter occlusion, two were confirmed with recanalization of the fistula, and one had abnormal collateral vessels between the descending thoracic aorta and the pulmonary artery. The patients with recanalization underwent the procedure again: one underwent lobectomy, and two underwent re-intervention for the fistula or collateral vessel. Two patients were diagnosed with HHT during follow-up, and two developed central nervous system (CNS) complications: one had a diffuse fistula and PFO and developed cerebral infarction in the ninth year of follow-up, and the other with multiple fistulas who had no indication for intervention or lobectomy developed heart failure and cerebral infarction 4 years after heart catheterization.
Three patients developed pulmonary artery hypertension (PAH). One was confirmed with mild PAH immediately after the first procedure but had no progression or specific drugs during the 4-year follow-up. Another who had undergone transcatheter occlusion for a fistula and collateral vessel was found with PAH immediately after the last procedure and developed severe PAH with high risk. The third patient with a diffuse fistula presented with increased pulmonary artery pressure 3 years after heart catheterization and developed severe PAH. According to the guidelines for pediatric pulmonary hypertension, PAH-targeted therapy in patients with lower-risk PAH is recommended. Of the two patients who accepted standardized anti-PAH-specific medicines, one with a diffuse fistula died from heart failure 4 years after the first heart catheterization, and another developed severe PH with high risk at the time of data collection.
Percutaneous transcatheter closure is the preferred treatment for PAVF. The surgical success and prognosis are related to the locations and types of fistulas. Isolated PAVF has a better prognosis than multiple and diffuse PAVFs. In this study, two patients with a diffuse fistula and one patient with multiple fistulas could not accept occlusion or lobectomy. They were all complicated by severe hypoxemia and hyperhemoglobinemia.
In patients with PAVF, more than 50% are associated with hereditary hemorrhagic telangiectasia (HHT), while in HHT, about 15% to 35% are associated with PAVF. HHT is an autosomal dominant disorder characterized by mucocutaneous and visceral vascular malformations that may occur in multiple organs. A diagnosis of HHT is based on at least three of the following symptoms: spontaneous epistaxis, cutaneous telangiectasia, arteriovenous malformations in internal organs, and a positive family history. In this study, only one patient was confirmed before the first operation due to recurrent hemorrhinia. HHT is often difficult to detect due to the lack of specific symptoms and physical signs during childhood and the prepubertal period. PAVFs associated with HHT probably carry more risk factors than simple PAVFs. Recanalization was found and treated in three cases of PAVF, two of which were diagnosed with HHT. Furthermore, other complications such as paradoxical embolism, stroke, and hemorrhage also need more attention in PAVFs associated with HHT.
PAVFs and PH have different pathophysiologic causes, but some studies suggest that PH associated with PAVFs is worthy of attention. First, some pathogenic mutations in genes are involved in PH and HHT. Second, gastrointestinal vascular malformation induces the disorders of vasoactive substances of pulmonary vasculature. There were three patients who developed PH during follow-up, two of whom had onset after transcatheter occlusion for PAVF, and one developed PH 3 years after heart catheterization. The true characteristics and causes of PH secondary to PAVF occlusion are still unclear. Firstly, the relative overload of pulmonary circulation after occlusion or lobectomy may be the trigger of PAH. Secondly, the abnormal development of pulmonary vasculature during the embryonic period is the root of PAVF and PH.
The most prominent disorders and complications of PAVF are hypoxemia and neurological paradoxical embolism. The incidence rate of neurological complications is more than 38% in PAVF. We also found that PFO can coexist with PAVF and is often misdiagnosed. Transcatheter closure is an effective therapy for PAVF. However, more prudent treatment and more rigorous follow-ups are needed, especially in cases where PAVF is associated with HHT.
doi.org/10.1097/CM9.0000000000000182
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