Avoid overtreatment in the setting of chronic total occlusions: The role of blood flow restoration in positive vascular remodeling

Abstract

A coronary chronic total occlusion (CTO) promotes negative remodeling in distal segments by negative vascular wall remodeling and plaque growth [ [1] Park J.J. Chae I.H. Cho Y.S. et al. The recanalization of chronic total occlusion leads to lumen area increase in distal reference segments in selected patients: an intravascular ultrasound study. JACC Cardiovasc. Interv. Aug 2012; 5: 827-836 Crossref PubMed Scopus (31) Google Scholar ]. As a result, epicardial coronary segments located distal to a CTO appear often as diffusely diseased arteries [ [2] Werner G.S. Schwarz G. Prochnau D. et al. Paclitaxel-eluting stents for the treatment of chronic total coronary occlusions: a strategy of extensive lesion coverage with drug-eluting stents. Catheter. Cardiovasc. Interv. 2006; 67: 1-9 Crossref PubMed Scopus (46) Google Scholar ]. It is unknown if these lesions are related to clinical events at follow-up and if they require percutaneous coronary intervention (PCI) with stenting, because blood flow restoration by recanalisation potentially leads to positive vascular remodeling in the distal reference segments [ [3] Gasparini G.L. Rossi M.L. Presbitero P. Follow-up improvement of distal vessel diameter after successful chronic total coronary occlusion recanalization. JACC Cardiovasc. Interv. Apr 2014; 7: e31-e33 Crossref PubMed Scopus (4) Google Scholar ]. Few data have been published to investigate the role of blood flow restoration in remodeling process after successful CTO PCI. A study of Park et al. [ [1] Park J.J. Chae I.H. Cho Y.S. et al. The recanalization of chronic total occlusion leads to lumen area increase in distal reference segments in selected patients: an intravascular ultrasound study. JACC Cardiovasc. Interv. Aug 2012; 5: 827-836 Crossref PubMed Scopus (31) Google Scholar ] showed that recanalization of a CTO led to lumen area increase in two-thirds of the patients. Independent predictors of lumen area increase were occlusion duration, a poor collateral flow and statin use. The degree of collateral flow might reflect the magnitude of hemodynamic stimuli deprivation, whereas the CTO duration correlates with the time in which vessels undergo a negative remodeling process. In a study of Galassi et al. [ [4] Galassi A.R. Tomasello S.D. Crea F. et al. Transient impairment of vasomotion function after successful chronic total occlusion recanalization. J. Am. Coll. Cardiol. Feb 21 2012; 59: 711-718 Crossref PubMed Scopus (70) Google Scholar ] authors have suggested that improvement of distal vessel diameter after CTO recanalization can be explained by an impaired endothelium-dependent and/or -independent vasomotion immediately after CTO recanalization, that improves at follow-up, or by a positive remodeling or by a combination of both. Gomez-Lara et al. [ [5] Gomez-Lara J. Teruel L. Homs S. et al. Lumen enlargement of the coronary segments located distal to chronic total occlusions successfully treated with drug-eluting stents at follow-up. EuroIntervention. Feb 2014; 9: 1181-1188 Crossref PubMed Scopus (32) Google Scholar ] have documented a notable late lumen enlargement between baseline and follow-up. These findings can be explained either by the absence of vasomotor response to non-endothelium-mediated stimuli immediately after the procedure and plaque regression. At follow-up, endothelium-independent response was restored in most patients, showing a remarkable luminal gain compared to the index procedure.