PAIVS occurs in 3 to 8 of 100,000 births, and catheter perforation is now an established procedure for correcting it. Management is more controversial in the setting of a borderline right ventricle.
“We would like to encourage physicians to consider this minimally invasive procedure in patients with comparatively small right ventricles, even if it does not appear that the ventricle will be capable of sustaining the full cardiac output in the long term,” Dr. Henry Chubb from Evelina Children’s Hospital, London, UK told Reuters Health in an email.
Dr. Chubb and colleagues evaluated the outcomes of 39 patients presenting with PAIVS who underwent catheter valvotomy. The procedure was successful (as defined by completion of valve perforation and balloon dilation of the right ventricular outflow tract) in 37 of the 39 patients.
The arterial duct was stented at the initial procedure in 14 patients (and subsequently in an additional 3 patients).
Following the procedure, mean right ventricular systolic pressure declined from 101 mm Hg to 51 mm Hg, while the mean pulmonary artery systolic pressure and the mean aortic systolic pressure remained stable.
For all 39 attempted procedures, the 30-day mortality rate was 15% (6 deaths). Overall, there were 7 deaths (19%) among the 37 successful procedures, all occurring within the first 35 days post-procedure.
Long-term comorbidities following the procedure included hemiparesis in 2 patients.
“In patients in whom the arterial duct was stented, there was a significantly reduced re-intervention rate and hospital stay,” the researchers note.
At the most recent follow-up 25 (83%) of the 30 survivors had a biventricular circulation. Eighteen of these 25 patients had required a further procedure, either surgical or catheter based.
Of the 5 patients not achieving biventricular circulation, 4 have a 1-and-a-half ventricle circulation, and 1 has a Fontan circulation.
Predictors of an unsuccessful procedure/death include smaller initial tricuspid valve annulus (a surrogate for right ventricular size) and pulmonary valve annulus z-score, whereas higher saturations at 1 year correlated highly with an eventual biventricular outcome.
Patients achieving biventricular outcome had higher tricuspid valve z-scores and a trend towards an increase in tricuspid valve size and z-score with time, whereas those achieving a univentricular circulation experienced a decrease in tricuspid valve z-score with time.
“Over the time period of the study, the technique of catheter pulmonary valvotomy has evolved from a pioneering intervention to become a mainstay of treatment for PAIVS at many institutions,” the investigators conclude. “In the long term, mortality outside of the acute phase of treatment is extremely low, and late complications are rare.”
“The pathology of PAIVS is a spectrum, ranging from patients with near normal right heart morphology to those with extremely small right ventricles,” Dr. Chubb explained. “We believe that decompression of the right ventricle will aid the development of a stable circulation. However, many patients will require additional support whilst the right ventricle remodels, and we feel that stenting of the duct in selected cases is an effective adjunct to therapy.”
Dr. Chubb said that this approach would not be suitable for patients with muscle between the cavity of the right ventricle and the pulmonary arteries; patients with significant abnormalities of the coronary anatomy; or patients with severe tricuspid regurgitation.
Dr. Chubb added, “We plan to extend the study to look more at the functional properties of the right ventricle. With this in mind, we are now looking for approval to allow the cohort to undergo cardiopulmonary exercise testing (CPET). We are particularly interested in the spectrum of ability of those at each of the biventricular outcome: those born with the smallest RV compared to those with the largest. We also continue to collect data on each patient receiving this treatment as our management strategy continues to evolve.”