Thorac Cardiovasc Surg 2016; 64 - OP133
DOI: 10.1055/s-0036-1571879

The Impact of Systemic-to-Pulmonary Collateral Flow (SPCF) in Patients after Bidirectional Cavopulmonary Connection (BCPC) or Fontan Operation Assessed with 4D Flow MRI

A. Al Bulushi 1, Ravesh M. Salehi 1, D. D. Gabbert 1, P. Wegner 1, I. Kristo 1, G. Fischer 1, J. Scheewe 2, T. Attmann 2, H. H. Kramer 1, C. Rickers 1
  • 1University Hospital Schleswig-Holstein UKSH, Department of Congenital Heart Disease and Pediatric Cardiology, Kiel, Germany
  • 2University Hospital Schleswig-Holstein UKSH, Department of Cardiovascular Surgery, Kiel, Germany

Background: Systemic-to-pulmonary collaterals (SPC) are found frequently in patients with single ventricle (SV) physiology but their hemodynamic relevance is unclear. The aim of our study was to quantify SPCF in patients with BCPC or Fontan-circulation utilizing novel MRI flow measurements. Furthermore, we compared SPCF with catheter findings and thought to identify associations for collateral development.

MethodsTwenty-four patients with SV physiology underwent a comprehensive cardiac MR study and conventional catheterization (Fontan: n = 12, age: 4.24 ± 1.08; BCPC: n = 12, age: 2.39 ± 0.55). Anatomical measurements of the pulmonary arteries and time-resolved 3D-flow measurements (“4D-flow”) using novel phase contrast techniques were performed in all patients. A dedicated software was used for quantification of SPCF for both lungs and color coded 4D-visualization of blood flow (GT-Flow™, Gyrotools Inc., Zurich). SPCF was graded from 0 to 3 for both lungs from catheter angiography and compared with MRI measurements.

Results: We found SPCF in all patients of both groups. In the BCPC group, the SPCF was 31% (range: 16–55%) of the SV stroke volume, with 25% and 39% in the right and left lung respectively. SPCF in the Fontan group was 36% (11–55%) with 25% in the right and 55% in the left lung. A comparison between 4D-velocity acquisitions and cardiac catheterization grading of SPCF showed significant correlation (r = 0.91, p< 0.001). Overall, in 37% of cases collateral flow was considered significant with both Methods. Pulmonary artery branch sizes showed significant inverse correlation with SPCF (r = 0.58, p< 0.001). In both groups, there was a strong correlation between SPCF and indexed SV enddiastolic and stroke volume (r = 0.53, p = 0.008 and r = 0.5, p = 0.012, respectively), indicating the hemodynamic relevance of SPCF.

Conclusion: 4D flow MRI identified significant SPCF in more than one-third of patients in BCPC or Fontan-circulation resulting in a significant hemodynamic burden for the single ventricle. Patients with small LPA-diameters are prone to develop SPCF.