Interventional closure of persistent foetal cardiac shunts including PDA and PFO : study of outcome, complications and novel methods

Abstract

Background: Persistent foramen ovale (PFO) and persistent ductus arteriosus (PDA) are two of the most common congenital heart defects (CHD). The incidence of PFO is reported to be between 10% and 35% (1, 2). In term infants, a PDA is seen in around one in 2000 births, accounting for 5% to 10% of all congenital heart disease (3, 4). Transcatheter closure of these lesions has become standard procedure in children and adults and has largely replaced surgery for these congenital cardiac defects. Cardiac catheterisation techniques require ionising radiation and are generally classified as high-radiation dose procedures according to the European Directive 2013/59/Euratom (5). New methods and materials have improved outcomes and safety, and have shortened periprocedural hospital stays for patients undergoing catheterisation.

Aim: This thesis aimed to study outcome and complications of new methods in patients undergoing heart catheterisation. The included studies aimed to evaluate new techniques, starting with vascular access and preclosure devices in the accessed vessel, to improve bleeding control and facilitate same-day discharge (SDD). A new method for surveillance of cancer risk during catheterisation procedures was introduced and can be used to alert the operator when the radiation has exceeded a certain cancer risk level. Lastly, several next-generation PDA devices were studied.

Methods: Four retrospective studies were conducted. In Study I, data from 238 paediatric patients were collected to estimate the risk of radiation-induced cancer death. Study II reviewed all patients undergoing PDA closure with an Amplatzer device over a fourteen-year period in a large centre in Tel Aviv. Study III investigated same-day discharge (SDD) of adult patients undergoing PFO closure. All patients who underwent transcatheter closure of a PFO at the Karolinska University Hospital in Stockholm between March 2017 and June 2020 were included. Study IV included all patients who underwent transcatheter PDA closure with a 5/7 Occlutech® duct occluder in three European centres in the UK, France and Sweden.

Results: More than 90% of the retrospective study cohort in Study I was within the range of very low (1–10 in 100,000) or low cancer risk level (1–10 in 10,000). No patient exceeded the high cancer risk level (> 1 in 100). In addition, a new concept of age- and gender-specific risk reference values (RRVs) related to population cancer risk was introduced. The results showed that the RRV for males was a factor 2–3 higher than that for females. In Study II, all Amplatzer devices demonstrated very good closure rates (> 99.5%) with a low rate of complications, such as device embolisation or left pulmonary artery (LPA) stenosis. A tendency toward less LPA stenosis with the Piccolo™ device was noted, and no aortic flow disturbance occurred in this study. The majority of complications (device embolisation and LPA stenosis) occurred in patients with a bodyweight < 15 kg. Study III focused on SDD of patients undergoing percutaneous closure of PFO. A total of 246 of 262 patients (94%) had SDD. In 166 (63%) patients, a Perclose ProGlide™ system was used for femoral vein access closure. Post-interventional arrhythmias were noted in 17 (6%) of the patients, and vascular complications in nine patients (3%). There was no difference in SDD between patients who received ProGlide (n=159, 96%) and patients who did not receive ProGlide™ (n=87, 91%, p=0.10). Eighteen paediatric patients with heart failure were included retrospectively in three study sites in Study IV. Eleven of them had a bodyweight below 12 kg, and pulmonary hypertension was noted in seven of the 18 patients. All patients underwent successful PDA closure with no complications with a 5/7 Occlutech® duct occluder.

Conclusions: Various aspects of cardiac catheterisation, from radiation risks, device choice, SDD and access site closure, have been studied in this thesis. Transcatheter closure of persistent foetal cardiac shunts is the standard treatment in full-term children and adults with low morbidity and mortality rates. New device development has improved PDA closure outcomes, even in small children with large PDAs. PFO closure has increased in the last five years due to several randomised controlled trials that catheterisations to treat CDH can be carried out with reasonably low radiation have reported a lower risk of recurrent ischemic stroke after PFO closure compared with medical therapy. Cardiac levels. Radiation-reducing tactics and the risk of radiation-induced cancer death must be taken into consideration, especially when treating younger patients.