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High rate of LAA thrombus in TAVR linked to periprocedural stroke
Among patients referred for transcatheter aortic valve replacement, the incidence of left atrial appendage thrombus is high, and left atrial appendage thrombus embolization may be a clinically relevant cause of periprocedural stroke, according to recent findings.
In the study, researchers evaluated 198 consecutive patients referred for possible TAVR at the James Cook University Hospital in Middlesbrough, United Kingdom, in July 2013. The researchers assessed all dual-phase cardiac CT scans performed on all patients between July 2013 and October 2015 for the possible existence of left atrial appendage (LAA) thrombus. They also assessed the images of all patients who underwent transesophageal echocardiography (TEE; n = 98).
The researchers also compiled baseline clinical characteristics, including demographics, atrial fibrillation burden and risk scores, prescription of anticoagulant therapy, technical procedural aspects, and clinical outcomes. They diagnosed and defined clinical outcomes, including mortality, vascular complications, bleeding and stroke/ischemic attack, based on the Valve Academic Research Consortium (VARC)-2 guidelines. All patients underwent clinical review at 6 weeks after TAVR, and at 6 months underwent follow-up echocardiography.
The researchers compared cardiac CT findings with those seen on TEE imaging.
LAA thrombus
They found that, of the overall cohort, 22 patients (11%) had definite LAA thrombus on cardiac CT, and 166 patients (84%) showed no signs of thrombus. In the remaining 10 patients, thrombus could not be ruled out on cardiac CT (5.1%). AF was revealed to be a significant risk factor for definite LAA thrombus on cardiac CT; 20 of 63 patients (32%) with AF had definite LAA thrombus on cardiac CT vs. two of 125 (1.6%) patients without history of AF (OR = 19.8; 95% CI, 4.5-88).
Compared with TEE, cardiac CT demonstrated sensitivity of 100%, specificity of 98% and a negative predictive value of 100%, according to the findings.
Of the patients referred for TAVR consideration, 124 (63%) ultimately underwent TAVR. During the study interval, TAVR had a 100% procedural success rate. The rate of 30-day mortality was 2.4% (3 of 124); the rate of 30-day major vascular complications was 2.4% (3 of 124); the rate of life-threatening bleeding was 1.6% (2 of 124) and the rate of major bleeding was 1.6% (2 of 124).
Among patients who underwent TAVR, the overall rate of stroke was 4.8% (n = 6). Two of these patients had definite LAA thrombus on cardiac CT, and both had clinical diagnoses of AF and were on a warfarin regimen at the time of cardiac CT, the researchers wrote.
Of the remaining four patients who had strokes, none had LAA thrombus on cardiac CT, none had AF diagnoses, and none were on an anticoagulation regimen. This equaled a stroke rate of 20% (2 of 10) in patients with LAA thrombus vs. 3.8% (4 of 105) in patients without LAA thrombus.
Stroke prevention strategies
In a related editorial, Samir R. Kapadia, MD, of the department of cardiovascular medicine, Heart and Vascular Institute at Cleveland Clinic, and colleagues noted that the risk for stroke in patients undergoing TAVR is related to both procedural and patient-specific factors.
“The current study demonstrates the utility of delayed-phase CT in assessing [LAA] thrombus,” Kapadia and colleagues wrote. “A systematic approach to investigate different strategies for stroke prevention including procedural modifications like [transcatheter embolic protection], diagnosis and prevention of AF-related strokes, and post-procedural pharmacotherapy will help to further improve outcomes of patients undergoing TAVR.” – by Jennifer Byrne
Disclosure: The researchers and editorial authors report no relevant financial disclosures.