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Coronary obstruction does not occur frequently after transcatheter aortic valve implantation (TAVI), but it can be a deadly complication, a multicenter registry showed.

Of 6,688 patients who underwent the procedure, only 44 (0.66%) developed symptoms from an obstructed coronary artery, according to Josep Rodes-Cabau, MD, of Laval University in Quebec City, and colleagues.

Percutaneous coronary intervention was attempted in most of the coronary obstruction cases -- and carried an 81.8% success rate -- but outcomes remained poor, with a 30-day mortality rate of 40.9%, the researchers reported online in the .

That "[highlights] the importance of anticipating and preventing the occurrence of this complication," they wrote.

Coronary obstruction after TAVI -- usually caused by "the displacement of the calcified native valve leaflets over the coronary ostia" -- has been consistently reported at a rate of lower than 1% in previous trials, including the PARTNER trial and various registries.

Earlier this year, Rodes-Cabau and his colleagues published a that included a total of 24 cases, but that information was culled mostly from case reports or small case series.

To explore the issue further, they examined data from a registry that retrospectively collected coronary obstruction cases from 81 centers in North America, Europe, South America, and Asia from January 2007 to January 2013.

Most of the 44 cases identified (88.6%) involved obstruction of the left coronary artery. The obstruction "was related to the displacement of a calcified native aortic valve leaflet towards the coronary ostium in all patients but one, who had an aortic valve cusp shearing and migration into the left coronary artery," the researchers wrote.

Most patients presented with persistent severe hypotension (68.2%) and electrocardiographic changes (56.8%), most commonly ST-segment elevation and ventricular arrhythmias.

Despite successful PCI in the majority of the cases, the mortality rate was high. Seven patients died during the TAVI procedure and another 11 who survived the procedure died within 30 days. Two more patients died from 30 days to 1 year, resulting in a 1-year mortality rate of 45.5%.

Several factors were significantly associated with the occurrence of symptomatic coronary obstruction, including older age, female sex, a lack of prior coronary artery bypass grafting (CABG), use of a balloon-expandable valve, receipt of a prior surgical aortic bioprosthesis, and a higher logistic EuroSCORE (P<0.05 for all).

And in a subset of patients who had pre-TAVI CT data available, anatomic predictors of obstruction included a lower left coronary artery ostia height and a smaller sinus of Valsalva diameter.

The percentage of patients with a left coronary artery height of less than 12 mm was significantly higher among patients with a coronary obstruction compared with matched patients who did not have an obstruction (86% versus 26.4%, P<0.001).

The researchers said the finding suggests that 12 mm might be a better cutoff than 10 mm for identifying an increased risk of coronary occlusion, from the American College of Cardiology, American Association for Thoracic Surgery, Society for Cardiovascular Angiography and Intervention, and Society of Thoracic Surgeons.

Most of the patients with an obstruction (71.4%) had a sinus of Valsalva diameter of less than 30 mm, compared with only 33% of the control patients (P<0.001).

And the percentage of patients with both a left coronary artery height of less than 12 mm and a sinus of Valsalva diameter of less than 30 mm was also significantly higher in the obstruction group (67.9% versus 13.3%, P<0.001), "meaning that the combination of these two anatomic factors has to be taken into account when evaluating the possibility of coronary obstruction due to TAVI," the authors wrote.

They acknowledged that the study was limited by the inclusion of symptomatic cases of obstruction only, the fact that reporting of the cases was voluntary, the lack of monitoring to ensure the accuracy of the data from the study sites, and the lack of centralized analysis of coronary angiograms.

From the American Heart Association:

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