A recently published study in the Journal of American College of Cardiology concluded that delayed coronary obstruction (DCO) occurring after transcatheter aortic valve replacement (TAVR) is an infrequent complication, associated with a high in-hospital mortality.
TAVR is the recommended treatment modality for intermediate and high-risk surgical patients with severe aortic stenosis. It has shown improved survivability and quality of life compared with medical therapy in high-risk patients restricting surgical replacement. While most of TAVR related complications are well known, a much rarer phenomenon, coronary obstruction, has long been recognized as a potential complication identified to occur seconds to minutes post valve placement. The authors state that there are a few case reports which have described DCO occurring in the hours and days following TAVR. Thus, the study gathered data and analyzed cases of DCO to ascertain better knowledge and understanding of this troubling complication.
The study is a statistical analysis of data retrospectively collected from an international multicenter registry consisting of 18 centers between November 2005 and December 2016. DCO was pre-defined according to a set criteria consisting of diagnosis by angiography, surgery, or autopsy at time of event. Data collected included baseline clinical features, echocardiographic findings, and procedural characteristics of the index procedure. Furthermore, data on clinical presentation, diagnosis, and management of the DCO complication, as well as in-hospital, early, and late clinical outcomes were also collected.
DCO as a rare but significant post-TAVR complication. Clinicians should be aware of its incidence so to have a lower threshold for performing coronary angiography when in doubt.
The results showed that during the study period, from a total of 17,092 patients who underwent TAVR, 38 cases had DCO (incidence 0.22%). DCO tends to occur more commonly after valve-in-valve procedure (0.89% vs. 0.18%; p < 0.001) and when self-expandable valves were used during the index procedure (0.36% vs. 0.11% balloon expandable; p < 0.01). The likely timing of occurrence was <24 hours after the procedure. Regarding the clinical presentation, cardiac arrest was the most frequent (31.6%; n = 12), followed by ST-segment elevation myocardial infarction (23.7%; n =9). The left coronary artery was obstructed in most cases and percutaneous coronary intervention was attempted in the majority of cases with stent implantation being successful in 68.8%. The overall in-hospital death rate was 50% and was higher if DCO occurred <7 days from the index procedure (62.5% vs. 28.6%; p =0.09).
Jabbour et al. have thus presented DCO as a rare but significant post-TAVR complication as it a has high mortality rate, and suggest that clinicians should be aware of its incidence so to have a lower threshold to performing coronary angiography when in doubt.
The authors also acknowledged some limitations of the study. Firstly, coronary obstruction had to be confirmed by angiography, surgery, or autopsy, so the real incidence may be under-reported. On the other hand, selection bias from centers reporting DCO may have influenced the actual incidence. Voluntary reporting by the investigators at each center was without any external monitoring to verify the accuracy of the data. Lastly, absence of comparison to a matched control group led to inability to ascertain predictors of this rare complication.
Source: Delayed Coronary Obstruction After Transcatheter Aortic Valve Replacement, http://www.onlinejacc.org/content/71/14/1513?sso=1&sso_redirect_count=2&access_token=
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