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Leaflet thrombosis relatively prevalent, but usually subclinical, after TAVR
In patients who have undergone transcatheter aortic valve replacement, hypoattenuated leaflet thickening appears to be relatively common but usually subclinical, according to recent findings.
Hypoattenuated leaflet thickening (HALT) is predicted by male sex, larger sinus of Valsalva and bioprosthesis size, and elevated D-dimer levels on follow-up, the researchers wrote.
In the study, the researchers prospectively evaluated data on 70 of 100 consecutive patients who underwent TAVR with the Sapien XT valve (Edwards Lifesciences) at Keio University Hospital in Tokyo between October 2013 and January 2015.
Patients identified for inclusion were assessed for HALT using multidetector CT evaluation before TAVR, at discharge, and at 6-month and 1-year follow-up, and had complete datasets (laboratory test, transthoracic echocardiography and multidetector CT). Clinical follow-up was conducted at 1, 3 and 6 months and 1 year for the first year, and then on a yearly basis.
The primary endpoints were HALT and reduced leaflet motion identified on multidetector CT, as well as all-cause mortality. Other clinical endpoints included stroke and transient ischemic attack based on the Valve Academic Research Consortium-2 criteria.
No symptoms
The researchers found that, of the 70 patients, HALT was identified in 10 patients overall, with one patient diagnosed at hospital discharge, seven patients at 6 months and 10 at 1 year. The 10 patients with HALT did not develop symptoms or demonstrate increase in pressure gradient on echocardiography during the follow-up interval.
Patients with HALT were more likely to be men vs. those without HALT (70% vs. 25%; P = .008). The multidetector CT study revealed that patients with HALT had a larger mean diameter of the sinus of Valsalva (mean diameter, 31 mm vs. 28.6 mm; P = .005), although no significant disparity was seen in the annulus area (397 mm2 vs. 368 mm2).
HALT was found in 6.1% of patients for whom a 23-mm valve was used vs. 33.3% of patients for whom a 26-mm valve was used (P = .006). This was attributed to the increased incidence of male sex and larger sinus of Valsalva in the patients with HALT. The two groups had similar ratios of the sinus of Valsalva to the transcatheter heart valve diameter (1.24 mm vs. 1.21 mm; P = .23).
Although no differences were seen in D-dimer levels between the groups at baseline (1.1 µg/mL vs. 0.9 µg/mL; P = .33) and at discharge (4 µg/mL vs. 3.1 µg/mL; P = .38), the HALT group demonstrated an increase in D-dimer levels at 6 months (2.3 µg/mL vs. 1.1 µg/mL; P = .002), and this increase was sustained at 1 year (2.7 µg/mL vs. 1.2 µg/mL; P = .006).
At 1 year, the mean pressure gradient was reduced in the HALT group (8.3 mm Hg vs. 11.1 mm Hg; P = .005). When compared with transcatheter valve size, the HALT and non-HALT patients had similar mean pressure gradients at 1 year, both in those with 26-mm valves (8.3 mm Hg vs. 9.6 mm Hg; P = .47) and those with a 23-mm valve (9 mm Hg vs. 11.5 mm Hg; P = .64). Because the patients with HALT did not show an increase in pressure gradient or demonstrate symptoms during follow-up, no further anticoagulation was administered.
Clinical outcomes similar
No significant differences were seen between HALT and non-HALT patients in all-cause mortality (0% vs. 1.7%; P = 1), NYHA functional class (P = .9), stroke (0% vs. 0%; P = 1) and TIA (0% vs. 1.7%; P = 1).
“Patients with elevated D-dimer levels during follow-up, male sex or large sinus of Valsalva and bioprosthesis size can be candidates for postprocedural [multidetector] CT scanning to detect HALT,” the researchers wrote. “If HALT is detected, the evaluation of hemodynamics and the need for anticoagulant therapy should be considered carefully.” – by Jennifer Byrne
Disclosure: Two researchers report serving as proctors for Edwards Lifesciences. Another researcher reports receiving grants from Toshiba Medical Systems.