Four-dimensional flow magnetic resonance imaging study to explain high prevalence of pulmonary vein stump thrombus after left upper lobectomy

Abstract

Background: Pulmonary vein (PV) stump thrombus, a known source of cerebral infarction, develops almost exclusively after left upper lobectomy; however, the mechanism remains unclear. We therefore evaluated the hemodynamics in the left atrium with four-dimensional flow magnetic resonance imaging (4D-flow MRI), which enables the simultaneous depiction of blood flow at three locations and the evaluation of hemodynamics. Methods: 4D-flow MRI was basically performed 7 days after lobectomy for cancer arising in the right upper lobe (n=11), right lower lobe (n=8), left upper lobe (n=13), or left lower lobe (n=8). We evaluated dynamic blood movement from the ipsilateral remaining PV, the resected PV stump, and the contralateral PVs into the left atrium using 4D-flow MRI.Results: There were some characteristic blood flow patterns that seemed to either promote or prevent PV stump thrombus. Promotive flow patterns were significantly more frequent and preventive flow patterns were significantly less frequent in patients who had undergone left upper lobectomy than in those who had undergone other lobectomy. Accordingly, the degree of blood turbulence near the vein stump, as measured by the extent of change in the blood movement, was significantly higher in patients who had undergone left upper lobectomy than in patients who had undergone other lobectomy. Conclusions: Our study revealed that left upper lobectomy likely causes blood turbulence near the vein stump through complicated blood streams in the left atrium, which can play a part in the development of vein stump thrombus. Further study to identify patients at high risk of vein stump thrombus is warranted.

Hemodynamic features underlying pulmonary vein stump thrombus formation after left upper lobectomy: four-dimensional flow magnetic resonance imaging study

“…We previously showed that the SD of the flow rate, representing the grade of to-and-fro blood movement, was significantly correlated with the length of the PV stump (9). We also showed that both the SD and PV stump length were significantly greater in patients who underwent LUL than in those who underwent other lobectomies, which seemed to contribute to the high incidence of PV thrombus after LUL.…”

“…We previously evaluated regional hemodynamics by visualizing the blood streamlines in the left atrium from pulmonary veins as well as by the quantitative analysis of the blood flow around PV stump on four-dimensional flow magnetic resonance imaging (4D flow MRI) in patients who underwent lung lobectomy (9). We detected several characteristic blood flow patterns in the left atrium that were observed predominantly after LUL.…”

4D Flow MR Imaging of the Left Atrium: What is Non-physiological Blood Flow in the Cardiac System?

“…11,12 Another group evaluated the "turbulence" in the LA in patients after lobectomy. 60 Care should be taken that some of the methodologies for the evaluation have not been confirmed except for their own study without any reference to healthy participants. 61…”

Why does pulmonary vein thrombus predominantly develop after left upper lobectomy?

“…It is my great honor to express my opinion on the editorial commentary (1) regarding our paper, 'Four-dimensional flow magnetic resonance imaging study to explain high prevalence of pulmonary vein stump thrombus after left upper lobectomy' (2). Firstly, we observed dynamic blood movement in the left atrium after lung lobectomy with four-dimensional flow magnetic resonance imaging (4D MRI) and identified some characteristic hemodynamic features that are predominantly found after left upper lobectomy (LUL).…”