CTA Detection of Left Atrial Stasis and Thrombus in Patients with Atrial Fibrillation

Abstract

We reviewed CTA and transesophageal echocardiographic images obtained in 861 consecutive patients with a history of AF undergoing same-day CTA and transesophageal echocardiogram (TEE) before AF ablation at a single hospital (2006-2013). CTA findings of LAA filling defects from acquisitions without electrocardiogram gating were compared to TEE features of LAA stasis (grade 0-4) and thrombus. Stasis grade 0 or 1 by TEE in the absence of thrombus was defined as a negative result. In addition, LAA peak flow velocity was assessed by TEE. Average age was 61 ± 10 years and 75% were male. On CTA, 161 patients (19%) had LAA filling defects on CTA and 21 had ≥grade 2 stasis on TEE, including two with thrombus, resulting in a positive predictive value of only 13%. However, among 670 CTA-negative patients, 669 (99%) were negative for thrombus or stasis by TEE with one false-negative CTA in a patient with grade 2 stasis by TEE but no thrombus, yielding a negative predictive value of 99.9%. Slow LAA Doppler flow velocity was the most important determinant of false-positive CTA results in multivariate analysis (P < 0.0001) CONCLUSION: LAA filling defects on CT are associated with slow LAA flow velocity. AF patients without LAA filing defects on CT are free of significant stasis and thrombus on TEE. It may be possible to eliminate TEE in up to 80% of AF ablation patients based on negative CTA findings.

The use of cardiac‐CT alone to exclude left atrial thrombus before atrial fibrillation ablation: Efficiency, safety, and cost analysis

“…The results of the safety analysis in our study shows that the use of CCTA only with delayed imaging protocol is enough to rule out a LAAT in patients who are at low to intermediate risk of stroke related to AF. This is in agreement with prior studies such as the one conducted by Wang et al . which showed that among 670 CCTA‐negative patients for LAAT or stasis, 669 (99%) were negative by TEE with one false‐negative CCTA in a patient with grade 2 stasis by TEE but no thrombus, yielding a NPV of 99.9%.…”

“…However, we were not able to show a significant cost difference when TEE was eliminated from the preprocedural imaging protocol. The CCTA results are consistent with prior literature which shows that the sole use CCTA with delayed imaging is a safe and effective method in ruling out a LAAT, potentially obviating the need for TEE prior to AFA procedure . Prior literature showed that, when using confirmatory intracardiac echocardiography as the reference standard, the use of CCTA‐alone with delayed imaging protocol had a 100% PPV, 100% NPV, 100% sensitivity, and a 100% specificity (when equivocal results were considered negative) .…”

“…In light of that, CCTA has been increasingly used for LAAT detection. Several studies investigated the use of CCTA in the assessment of LAAT in preprocedural evaluation for AF ablation . A challenge with CCTA is that LAA filling defects may represent thrombus or incomplete contrast mixing with blood.…”

Left Atrial Posterior Wall Thrombus After Posterior Wall Ablation

“…10 Enlargement of the cardiac chambers causes stasis of blood and an increased risk of thrombus formation in the left atrial appendage and the left atrium itself. 11 Our patient, with a history of cardiomy-opathy and mitral regurgitation, had this risk. One paper suggests that chronic mitral regurgitation can cause a rare type C calcification in the posterior wall of the left atrium.…”

Prone-position computed tomography in the late phase for detecting intracardiac thrombi in the left atrial appendage before catheter ablation for atrial fibrillation

“…Although the detection of thrombi using contrast CT exhibits excellent negative predictive values (99-100%), the positive predictive value is still low, at 13-31%. [14][15][16] This may be attributed predominantly to difficulties in distinguishing real thrombi from circulatory stasis in the LAA, particularly at a low blood velocity. The discrimination between thrombi and circulatory stasis is more crucial in patients with persistent or longstanding AF than in those with paroxysmal AF; in the former population, 28% of patients showed CDs on sCT in the early phase and as a reference of TEE or ICE, the positive and negative predictive values were 40.7% and 100%, respectively.…”