Planning percutaneous coronary interventions using computed tomography angiography and fractional flow reserve-derived from computed tomography: A state-of-the-art review.

Fractional flow reserve derived by coronary computed tomography angiography (CTA; FFRCT) is an accurate noninvasive method for identifying coronary artery disease (CAD) and detecting hemodynamically significant stenosis. Although initially proposed as noninvasive tools to "rule out" significant CAD in low-risk patients, CTA and FFRCT are now utilized in higher-risk patients. Furthermore, new applications of CTA and FFRCT include a planning tool for percutaneous coronary intervention (PCI), which allows the cardiologist to assess lesion-specific ischemia, plan stent locations and sizes, and use virtual remodeling of the lumen (virtual stenting) to assess the functional impact of PCI. The purpose of this review is to discuss the principles of CTA and FFRCT acquisition, and their application for PCI planning, even before invasive angiography is performed.

Late Outcomes of Patients in the Emergency Department With Acute Chest Pain Evaluated With Computed Tomography-Derived Fractional Flow Reserve.

Computed tomography (CTA)-derived fractional flow reserve (FFRCT) guides the need for invasive coronary angiography (ICA). Late outcomes after FFRCT are reported in stable ischemic heart disease but not in acute chest pain in the emergency department (ACP-ED). The objectives are to assess the risk of death, myocardial infarction (MI), revascularization, and ICA after FFRCT. From 2015 to 2018, 389 low-risk patients with ACP-ED (negative biomarkers, no electrocardiographic ischemia) underwent CTA and FFRCT and were entered into a prospective institutional registry; patients were followed up for 41 ± 10 months. CTA stenosis ≥50% was present in 81% of the patients. Positive (FFRCT ≤0.80) and negative FFRCT were observed in 124 (32%) and 265 patients (68%), respectively. ICA was performed in 108 of 124 patients (87%) with positive FFRCT and 89 of 265 patients (34%) with negative FFRCT (p <0.00001). Revascularization was performed in 87 of 124 (70%) patients with positive FFRCT and in 22 of 265 (8%) with negative FFRCT (p <0.00001). Appropriateness of revascularization was established by blinded adjudication of ICA and invasive FFR using practice guidelines; revascularization was appropriate in 81 of 124 (65%) and 6 of 265 (2%) of FFRCT-positive and -negative patients, respectively (p <0.00001). At follow-up, for patients with positive versus negative FFRCT, the rates were 0.8% versus 0% for death (p = 0.32) and 1.6% versus 0.4% for MI (p = 0.24). In conclusion, in low-risk patients with ACP-ED who underwent CTA and FFRCT, the risk of late death (0.2%) and MI (0.7%) are low. Negative FFRCT is associated with excellent long-term prognosis, and positive FFRCT predicts obstructive disease requiring revascularization. FFRCT can safely triage patients with ACP-ED and reduce unnecessary ICA and revascularization.

Impact of Defibrillator Electrode Placement on Outcome of Electrical Cardioversion of Atrial Fibrillation: A Pilot Observational Study.

BACKGROUND: Anterior-posterior electrode placement is preferred in electrical cardioversion of atrial fibrillation. However, the optimal anterior-posterior electrode position in relation to the heart is not studied. METHODS AND RESULTS: We performed a prospective observational study on patients presenting for cardioversion of atrial fibrillation. Electrodes were placed in the anterior-posterior position and shock was delivered in a step-up approach (100 J→200 J→360 J). Fluoroscopic images were obtained, and distances were measured from points A, midanterior electrode; and B, midposterior electrode, to midpoint of the cardiac silhouette. Patients requiring one 100 J shock for cardioversion success (group I) were compared with those requiring >1 shock/100 J (group II). Logistic regression was used to determine the impact of electrode distance on low energy (100 J) cardioversion success. Computed tomography scans from this cohort were analyzed for anatomic landmark correlation to the cardiac silhouette. Of the 87 patients included, 54 (62%) comprised group I and 33 (38%) group II. Group I had significantly lower distances from the mid-cardiac silhouette to points A (5.0±2.4 versus 7.4±3.3 cm; P<0.001) and B (7.3±3.0 versus 10.0±3.8 cm; P=0.002) compared with group II. On multivariate analysis, higher distances from the mid-cardiac silhouette to point A (odds ratio, 1.33 [95% CI, 1.07-1.70]; P=0.01) and B (odds rsatio, 1.24 [95% CI, 1.05-1.50]; P=0.01) were independent predictors of low energy (100 J) cardioversion failure. Based on review of computed tomography scans, we suggest that the xiphoid process may be an easy landmark to guide proximity to the myocardium. CONCLUSIONS: In anterior-posterior electrode placement, closer proximity to the cardiac silhouette predicts successful 100 J cardioversion irrespective of clinical factors.

Aortic Regurgitation, Time to Aortic Valve Reintervention, and Mortality in Degenerated Trifecta Versus Non-Trifecta Bioprosthesis.

On July 31, 2023, the Trifecta valve was withdrawn from the market after concerns regarding early (≤5 years) structural valve deterioration (SVD), mainly as aortic regurgitation (AR). Our aim was to determine the timing, mechanism, and impact of bioprosthetic SVD in patients who underwent redo aortic valve replacement (redo-AVR) with either redo-SAVR or valve-in-valve transcatheter aortic valve replacement (TAVR) using Trifecta versus other bioprosthetic valves. Patients who underwent redo-AVR for SVD at our institution were categorized into 2 groups based on the valve type: Trifecta versus non-Trifecta. Multivariate Cox proportional hazard model and Kaplan-Meier curves were used to compare mortality. A total of 171 patients were included; 58 (34%) had previous SAVR with a Trifecta valve and 113 (66%) with non-Trifecta valve. A total of 103 patients (60%) underwent valve-in-valve TAVR and 68 redo-SAVR (40%). The age, gender, and Society of Thoracic Surgeons score were similar between Trifecta and non-Trifecta groups. In patients with bioprosthetic valves requiring redo-AVR, Trifecta valves had an earlier onset of greater than moderate AR (4.5 vs 11.9 years, p <0.001) and earlier time to redo-AVR (5.5 vs 12 years, p <0.001). AR was more common as the mechanism of SVD in Trifecta versus non-Trifecta valves (55.2% vs 30.1%, p = 0.006). All-cause adjusted mortality from index SAVR was higher in the Trifecta than in non-Trifecta group (hazard ratio 4.1, 95% confidence interval 1.5 to 11.5, p = 0.007). In conclusion, compared with non-Trifecta valves, Trifecta valves exhibit early SVD primarily as AR and progress rapidly to significant SVD requiring redo-AVR. Mortality is significantly higher with Trifecta than in non-Trifecta valves, potentially impacting the results of SAVR versus TAVR studies.

Importance of measurement site on assessment of lesion-specific ischemia and diagnostic performance by coronary computed tomography Angiography-Derived Fractional Flow Reserve.

BACKGROUND: Values of fractional flow reserve (FFRCT) by coronary computed tomography angiography (CTA) decline from the ostium to the terminal vessel, irrespective of stenosis severity. The purpose of this study is to determine if the site of measurement of FFRCT impacts assessment of ischemia and its diagnostic performance relative to invasive FFR (FFRINV). METHODS: 1484 patients underwent FFRCT; 1910 vessels were stratified by stenosis severity (normal; <25%, 25-50%, 50-70%, and >70% stenosis). The rates of positive FFRCT (≤0.8) were determined by measuring FFRCT from the terminal vessel and from distal-to-the-lesion. Reclassification rates from positive to negative FFRCT were calculated. Diagnostic performance of FFRCT relative to FFRINV was evaluated in 182 vessels using linear regression, Bland Altman analysis, and receiver operating characteristic (ROC) curves. RESULTS: Positive FFRCT was identified in 24.9% of vessels using terminal vessel FFRCT and 10.1% using FFRCT distal-to-the-lesion (p â€‹< â€‹0.001). FFRCT obtained distal-to-the-lesion resulted in reclassification of 59.6% of positive terminal FFRCT to negative FFRCT. Relative to FFRINV, there were improvements in specificity (50% to 86%, p â€‹< â€‹0.001), diagnostic accuracy (65% to 88%, p â€‹< â€‹0.001), positive predictive value (50% to 78%, p â€‹< â€‹0.001), and area-under-the-curve (AUC, 0.83 to 0.91, p â€‹< â€‹0.001) when FFRCT was measured distal-to-the-lesion. CONCLUSION: FFRCT values from the terminal vessel should not be used to assess lesion-specific ischemia due to high rates of false positive results. FFRCT measured distal-to-the-lesion improves the diagnostic performance of FFRCT relative to FFRINV, ensures that FFRCT values are due to lesion-specific ischemia, and could reduce the rate of unnecessary invasive procedures.

Clinical Use of CT-Derived Fractional Flow Reserve in the Emergency Department.

OBJECTIVES: This study sought to examine the feasibility, safety, clinical outcomes, and costs associated with computed tomography-derived fractional flow reserve (FFRCT) in acute chest pain (ACP) patients in a coronary computed tomography angiography (CTA)-based triage program. BACKGROUND: FFRCT is useful in determining lesion-specific ischemia in patients with stable ischemic heart disease, but its utility in ACP has not been studied. METHODS: ACP patients with no known coronary artery disease undergoing coronary CTA and coronary CTA with FFRCT were studied. FFRCT ≤0.80 was considered positive for hemodynamically significant stenosis. RESULTS: Among 555 patients, 297 underwent coronary CTA and FFRCT (196 negative, 101 positive), whereas 258 had coronary CTA only. The rejection rate for FFRCT was 1.6%. At 90 days, there was no difference in major adverse cardiac events (including death, nonfatal myocardial infarction, and unexpected revascularization after the index visit) between the coronary CTA and FFRCT groups (4.3% vs. 2.7%; p = 0.310). Diagnostic failure, defined as discordance between the coronary CTA or FFRCT results with invasive findings, did not differ between the groups (1.9% vs. 1.68%; p = NS). No deaths or myocardial infarction occurred with negative FFRCT when revascularization was deferred. Negative FFRCT was associated with higher nonobstructive disease on invasive coronary angiography (56.5%) than positive FFRCT (8.0%) and coronary CTA (22.9%) (p < 0.001). There was no difference in overall costs between the coronary CTA and FFRCT groups ($8,582 vs. $8,048; p = 0.550). CONCLUSIONS: In ACP, FFRCT is feasible, with no difference in major adverse cardiac events and costs compared with coronary CTA alone. Deferral of revascularization is safe with negative FFRCT, which is associated with higher nonobstructive disease on invasive angiography.

Peripherally Embolizing Aortic Thrombus: The Work-Up, Management, and Outcome of Primary Aortic Thrombus.

BACKGROUND: Primary aortic thrombus is an uncommon entity and not frequently reported in the literature. Herein, we discuss the presentation and management of a patient with a primary thoracic mural thrombus. CASE SUMMARY: A 46-year-old female with past medical history of tobacco dependence presented for low-grade fever and sudden onset, severe right upper quadrant abdominal pain with associated nausea and vomiting. Computed tomography (CT) revealed an intraluminal polypoid filling defect arising from the isthmus of the aorta projecting into the proximal descending aorta and findings consistent with infarction of the spleen and right kidney. Infectious, autoimmune, hematologic, and oncologic work-up were all unyielding. The patient was started on heparin and later transitioned to apixaban 5 mg twice a day and 81 mg of aspirin daily. She was also counseled regarding smoking cessation. Two months follow-up CT revealed resolution of the thrombus. Patient had no further thromboembolic complications. DISCUSSION: We present a unique case of primary aortic thrombus. To our knowledge, this is the first reported case managed successfully with a NOAC. This diagnosis is one of exclusion and through work-up should be completed. Our aim is to raise awareness of this condition and successful management with apixaban in low-risk patients.

Optimizing the Technique for Invasive Fractional Flow Reserve to Assess Lesion-Specific Ischemia.

BACKGROUND: Invasive fractional flow reserve (FFRINV) is the standard technique for assessing myocardial ischemia. Pressure distortions and measurement location may influence FFRINV interpretation. We report a technique for performing invasive fractional flow reserve (FFRINV) by minimizing pressure distortions and identifying the proper location to measure FFRINV. METHODS: FFRINV recordings were obtained prospectively during manual hyperemic pullback in 100 normal and diseased coronary arteries with single stenosis, using 4 measurements from the terminal vessel, distal-to-the-lesion, proximal vessel, and guiding catheter. FFRINV profiles were developed by plotting FFRINV values (y-axis) and site of measurement (x-axis), stratified by stenosis severity. FFRINV≤0.8 was considered positive for lesion-specific ischemia. RESULTS: Erroneous FFRINV values were observed in 10% of vessels because of aortic pressure distortion and in 21% because of distal pressure drift; these were corrected by disengagement of the guiding catheter and re-equalization of distal pressure/aortic pressure, respectively. There were significant declines in FFRINV from the proximal to the terminal vessel in normal and stenotic coronary arteries (P<0.001). The rate of positive FFRINV was 41% when measured from the terminal vessel and 20% when measured distal-to-the-lesion (P<0.001); 41.5% of positive terminal measurements were reclassified to negative when measured distal-to-the-lesion. Measuring FFRINV 20 to 30 mm distal-to-the-lesion (rather than from the terminal vessel) can reduce errors in measurement and optimize the assessment of lesion-specific ischemia. CONCLUSIONS: Meticulous technique (disengagement of the guiding catheter, FFRINV pullback) is required to avoid erroneous FFRINV, which occur in 31% of vessels. Even with optimal technique, FFRINV values are influenced by stenosis severity and the site of pressure measurement. FFRINV values from the terminal vessel may overestimate lesion-specific ischemia, leading to unnecessary revascularization.

Assessment of lesion-specific ischemia using fractional flow reserve (FFR) profiles derived from coronary computed tomography angiography (FFRCT) and invasive pressure measurements (FFRINV): Importance of the site of measurement and implications for patient referral for invasive coronary angiography and percutaneous coronary intervention.

BACKGROUND: Fractional flow reserve (FFR)-derived from computed tomography angiography (CTA; FFRCT) and invasive FFR (FFRINV) are used to assess the need for invasive coronary angiography (ICA) and percutaneous coronary intervention (PCI). The optimal location for measuring FFR and the impact of measurement location have not been well defined. METHODS: 930 patients (age 60.7 + 10 years, 59% male) were included in this study. Normal and diseased coronary arteries were classified into stenosis grades 0-4 in the left anterior descending artery (LAD, n = 518), left circumflex (LCX, n = 112) and right coronary artery (RCA, n = 585). FFRCT (n = 1215 arteries) and FFRINV (n = 26 LAD) profiles were developed by plotting FFR values (y-axis) versus site of measurement (x-axis: ostium, proximal, mid, distal segments). The best location to measure FFR was defined relative to the distal end of the stenosis. FFR ≤0.8 was considered positive for ischemia. RESULTS: In normal and stenotic coronary arteries there are significant declines in FFRCT and FFRINV from the ostium to the distal vessel (p < 0.001), due to lesion-specific ischemia and to effects unrelated to the lesion. A reliable location (distal to the stenosis) is 10.5 mm [IQR 7.3-14.8 mm] for FFRCT and within 20-30 mm for FFRINV. Rates of positive FFR (from the distal vessel) reclassified to negative FFR (distal to the stenosis) are 61% (FFRCT) and 33% (FFRINV). CONCLUSION: FFRCT and FFRINV values are influenced by stenosis severity and the site of measurement. FFR measurements from the distal vessel may over-estimate lesion-specific ischemia and result in unnecessary referrals for ICA and PCI.