Why can pulmonary vein stenoses created by radiofrequency catheter ablation worsen during and after follow-up? A potential explanation.
BACKGROUND
Radiofrequency catheter ablation of excitation foci inside pulmonary veins (PV) generates stenoses that can become quite severe during or after the follow-up period. Since severe PV stenoses have most often disastrous consequences, it would be important to know the underlying mechanism of this temporal evolution. The present study proposes a potential explanation based on mechanical considerations.


METHODS
we have used a mathematical-physical model to examine the cyclic increase in axial wall stress induced in the proximal (= upstream), non-stenosed segment of a stenosed pulmonary vein during the forward flow phases. In a representative example, the value of this increase at peak flow was calculated for diameter stenoses (DS) ranging from 1 to 99%.


RESULTS
The increase becomes appreciable at a DS of roughly 30% and rise then strongly with further increasing DS value. At high DS values (e.g. > 90%) the increase is approximately twice the value of the axial stress present in the PV during the zero-flow phase.


CONCLUSIONS
Since abnormal wall stresses are known to induce damages and abnormal biological processes (e.g., endothelium tears, elastic membrane fragmentations, matrix secretion, myofibroblast generation, etc) in the vessel wall, it seems plausible that the supplementary axial stress experienced cyclically by the stenotic and the proximal segments of the PV is responsible for the often observed progressive reduction of the vessel lumen after healing of the ablation injury. In the light of this model, the only potentially effective therapy in these cases would be to reduce the DS as strongly as possible. This implies most probably stenting or surgery.
Doriot
Pierre-André
PA
Cardiology Department, University Hospital of Geneva, Geneva, Switzerland. pierre-andre.doriot@hcuge.ch
Dorsaz
Pierre-André
PA
Shah
Dipen Chandrakant
DC
D000792:Angiography; D001281:Atrial Fibrillation / Q000601:surgery; D001783:Blood Flow Velocity; D017115:Catheter Ablation / Q000009:adverse effects*; D018450:Disease Progression; D004562:Electrocardiography; D005500:Follow-Up Studies; D006801:Humans; D008955:Models, Cardiovascular; D011183:Postoperative Complications; D011668:Pulmonary Veno-Occlusive Disease / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D011669:Pulmonary Wedge Pressure / Q000502:physiology