Prevalence of pulmonary hypertension in adults after atrial switch and role of ventricular filling pressures

Prevalence of pulmonary hypertension in adults after atrial switch and role of ventricular filling pressures.

Miranda WR, Jain CC, Connolly HM, DuBrock HM, Cetta F, Egbe AC, Hagler DJ.

Heart. 2020 Oct 7:heartjnl-2020-317111. doi: 10.1136/heartjnl-2020-317111. Online ahead of print.

PMID: 33028672


Take Home Points:

In patients palliated with an atrial switch repair for transposition of the great arteries (TGA):

  • Prevalence of an elevated systolic RV end-diastolic pressure was low (1/3 of patients)
  • Almost 60% had an increased pulmonary arterial wedge pressure (PAWP), with prominent V waves
  • Elevation in pulmonary pressures was present in nearly all patients who had a concomitant elevation in PAWP

Commentary from Dr. Blanche Cupido (Cape Town, South Africa), section editor of ACHD Journal Watch: Both systemic RV systolic and diastolic dysfunction are well known complications after atrial switch procedures for Transposition of the Great Arteries (TGA). The contribution and effect of atrial baffles on cardiac output and ventricular filling is poorly understood. This is a retrospective review aimed at assessing the prevalence of elevated systemic filling pressures and pulmonary arterial hypertension late after atrial switch repairs.

All adult patients with TGA and an atrial patients who underwent cardiac catheterization at the Mayo Clinic between January 2004 and December 2018. Patients with single ventricle physiology and those with atrial switch take-downs were excluded.

Forty-two patients were included in the analysis. Their mean age at time of cardiac catheterization was 37.6 years, the median age at atrial switch surgery was 15 months. 90.5% of patients had a Mustard palliation. In 36 patients (85.7%), moderate or greater RV systolic dysfunction was noted. The mean sRVEF was 33%. In 35.7%, moderate or greater TR was noted.

In terms of cardiac Catheterisation data:

  • Pulmonary venous baffle obstruction in 16.7%
  • Systemic venous baffle obstruction in 54.7%

(in 10 cases percutaneous interventions were performed)

  • Mean sRVEDP 13.2mmHg ±5.1mmHg.
  • Mean Right PAWP 18.9, mean Left PAWP 18.5mmHg.
  • sRVEDP was significantly lower than both right and left PAWP, even once baffle obstruction was excluded (right difference -2.4mmHg, left difference -2.5mmHg, p=0.02 and 0.004 respectively).
  • Pulmonary venous baffle stiffness therefore likely plays a significant role in ventricular filling pressures.
  • An elevated sRVEDP >15mmHg was seen in 35.1% of patients (older at the time of atrial switch with no other clinical differences).
  • An elevated PAWP >15mmHg seen in 58.1% of patients (more likely to have a higher prevalence of NYHA class 3, to be on diuretic therapy, to have moderate or greater RV systolic dysfunction, and a lower EF.
  • Pulmonary hypertension was seen in 47.5% of patients (n=17).
  • Median PVR 1.3 Woods units.
  • Among those with pulmonary hypertension, PAWP > 15mmHg in all but one patient.

In addition to the systolic and diastolic dysfunction in the systemic RV, the pulmonary venous baffle has an important role in augmenting preload and on ventricular filling pressures as shown in this study by the relatively normal/low RVEDP and the elevated PAWP- with no end-diastolic gradient and a large v wave (as shown above). This is attributed to a combination the pulmonary venous atrium being of a small size compared to the left atrium, the baffle is non-distensible/partially calcified and increased atrial fibrosis/scarring.