Relationship of pulmonary artery wedge pressure to left atrial pressure and pulmonary vascular resistance in preoperative Fontan patients

Routine Surveillance Catheterization is Useful in Guiding Management of Stable Fontan Patients

We developed a Fontan surveillance catheterization protocol as part of routine assessment of stable patients 10 years after Fontan completion. The surveillance catherization includes hemodynamic assessment with inhaled nitric oxide, angiography, liver biopsy, and transcatheter intervention if indicated. We aimed to describe hemodynamic and liver biopsy findings, response to pulmonary vasoreactivity testing, rates of transcatheter intervention, and changes in medical therapy following surveillance catheterization in stable Fontan patients. A single-center retrospective review of Fontan patients undergoing surveillance catheterization between November 2014 and May 2019 was performed. Liver biopsies were independently scored by two pathologists. Sixty-three patients underwent surveillance catheterization (mean age 14.6 ± 3.0 years). The mean Fontan pressure was 11.8 ± 2.1 mmHg. The mean cardiac index was 2.9 ± 0.6 L/min/m². In the 51 patients who underwent pulmonary vasoreactivity testing, there was a significant decrease in median pulmonary vascular resistance (1.8 [range 0.8-4.1] vs 1.4 [range 0.7-3.0] Wood units × m²; p < 0.001). The mean cardiac index increased (3.0 ± 0.6 vs 3.2 ± 0.7 L/min/m², p = 0.009). The Fontan pressure did not change significantly. Fifty-seven patients underwent liver biopsy, and all but one showed fibrosis. Nineteen patients (33.3%) demonstrated bridging fibrosis or cirrhosis. Twenty-five patients underwent 34 transcatheter interventions. Pulmonary artery or Fontan stent placement was performed in 19 patients. Phosphodiesterase type 5 inhibitors were initiated in nine patients following surveillance catheterization. Routine surveillance catheterization with liver biopsy in adolescent Fontan patients reveals information that can guide interventional and medical management. Further long-term follow-up and assessment are indicated to assess the benefit of these interventions.

Can the Pulmonary Artery Wedge Pressure be Used Reliably as a Surrogate for the Left Atrial Mean Pressure in Pre-Fontan Evaluation?

The correlation between mean pulmonary artery wedge pressure (PAWP) and left atrial mean pressure (LAMP) has been poorly studied in patients with single ventricle (SV) physiology (Bernstein et al. in Pediatr Cardiol 33: 15-20 2012). The aim of this study is to determine if the PAWP can be used safely as a surrogate to the LAMP to calculate the pulmonary vascular resistance (PVR) during the pre-Fontan evaluation. Also, we aimed to understand if the presence of significant systemic-to-pulmonary collaterals (SPCs) is a confounding factor for accurate estimation of the LAMP. From February 2007 to February 2017, forty-one patients were eligible for inclusion in the study. These patients were varied in terms of underlying cardiac malformation. Sex distribution was equal with 20 males and 21 females. Median weight was 11.8 kg, median body surface area was 0.51 m², median age at catheterization was 2 years, and the median age at Glenn surgery was 5 months. We found the left and right PAWP and LAMP correlated strongly and the differences in the measurements were negligible. Similar findings were observed when calculating PVRs using PAWP and LAMP. These findings were more pronounced in the absence of significant SPCs. PAWP and LAMP correlation was still valid in the presence of significant SPCs; however, the correlation among the calculated PVRs was more attenuated.

Optimal Transducer Level for Atrial and Pulmonary Arterial Pressure Measurement in Patients with Functional Single Ventricle

This study aimed to investigate the optimal transducer level for accurate measurement of atrial and pulmonary arterial pressures in the supine position for patients with functional single ventricle. Contrast-enhanced chest computed tomographic images of 108 patients who underwent either the bidirectional cavopulmonary shunt (BCPS) placement or the Fontan procedure were reviewed. Vertical distances from the skin of the back to the uppermost levels of fluid in the single atrium or the pulmonary artery confluence and their ratios to the greatest anteroposterior (AP) diameter of the thoracic cage were determined. In patients who underwent BCPS, the ratios of the uppermost levels of blood in the atrium and pulmonary artery confluence to the greatest AP diameter of the thorax were 76.0 ± 8.1 and 56.3 ± 5.5 %, respectively. The distance (mm) between these two levels was calculated as 24.2 + 0.31 × age (years) (r ² = 0.08, P < 0.03). In patients who underwent the Fontan procedure, the ratios were 79.3 ± 10.0 and 58.3 ± 5.8 %, respectively. The distance (mm) between these two levels was calculated as 31.1 + 0.44 × age (years) (r ² = 0.05, P < 0.11). The optimal transducer levels for measuring atrial and pulmonary arterial pressures in the supine position are 75-80 and 55-60 % of the AP diameter of the thorax, respectively, in patients with functional single ventricle. We should consider the difference of the pressure when atrial and pulmonary arterial pressures were measured with the same level of transducers.