Original title: Coronary Obstruction After Transcatheter Aortic Valve Implantation. A Systematic Review. Reference: Henrique Barbosa Ribeiro et al. J Am Coll Cardiol Intv 2013. Article in press.
In the context of Transcatheter Aortic Valve Implantation (TAVI) there can be complications such as conduction disturbances, bleeding, residual aortic insufficiency or vascular complications, all of which have been detailed with their corresponding predisposing factors, prognosis, prevention strategies and eventual treatment. However, historically dreaded, coronary obstruction post TAVI that is considered to be life threatening has not been thoroughly looked into. The aim of this systematic review was to describe the baseline characteristics, management and evolution of patients presenting coronary obstruction after TAVI. Between 2002 and 2012, 24 cases presenting this complication were found in the literature. These publications were reports of cases or small series with no more than 5 cases per study.
Patient mean age was 83 ± 7 years and 83% were women. CT scans showed a mean left coronary ostium height of 10.3 ± 1.6 mm and aortic root width of 27.8 ± 2.8 mm, both significantly smaller than the average found in the literature (13.5 mm mean left coronary ostium height and 33.4 aortic root width; p<0.01). The Edwards balloon-expandable valve had been used in 87.5% of patients. Most cases presented severe and persistent hypotension (87.5%) immediately after valve implantation (83.3%) though in some patients it presented after a few hours or even 2 days afterwards. The most frequently compromised artery was the LCA (83.3%) and previous myocardial revascularization surgery was a protecting factor against this complication, as expected.
The obstruction mechanism was the displacement of a calcified native valve towards the ostium. Attempting to solve this complication, PCI was attempted in 23 patents (95.8%) and it was successful in 21 patients (91.3%). Significant stent compression requiring a second stent was observed in 3 patients, and surgery was required in 2 patients. Hospital mortality rate for this group was 8,3% and all patients with successful PCI were discharged; there were no cases of stent thrombosis or repeated revascularization.
Conclusion
Coronary obstruction is a rare after TAVI complication, but potentially life threatening. It was most frequently observed in women with no previous revascularization surgery that received a balloon expandable valve. This complication can be dismissed in cases of sustained hypertension after TAVI, in which case PCI is feasible and effective in most cases.
Editorial Comment:
Being a review, the study is limited, since it may be leaving out cases were treatment had failed. The fact that CT data were not available to all patients is also a limitation, especially in the presence of calcium deposits in the cusps. Though ostium height has historically been considered a risk factor and a 10mm height has been proposed as a safe cut off, half of patients had more than 10 mm, which suggests there are other factors. Complications resulted more frequent in women, with smaller root width and shorter ostium than men, which could explain the difference or at least account for a part of it. Core Valve implantation recommendation is ≥ 14 mm ostium height (though this may not be respected in may centers) and there is no formal factory recommendation regarding this issue for the Edwards valve; this also may explain part of the difference.
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