Carotid to Left Subclavian Artery Bypass Grafting for the Treatment of Coronary Subclavian Steal Syndrome.

Recurrent angina after coronary artery bypass grafting is rarely caused by left subclavian artery (LSCA) stenosis resulting in reduced left internal mammary artery blood flow. We present 2 cases of coronary-subclavian artery steal syndrome resulting from LSCA stenosis and their successful surgical management with left carotid to LSCA bypass. Based on the successful management described in this case report, and the limitations of other options in addressing coronary-subclavian artery steal syndrome, left carotid to LSCA bypass surgery should be considered for revascularization in patients who develop postoperative coronary-subclavian artery steal syndrome due to LSCA stenosis.

La récidive d'angine après le pontage aortocoronarien est rarement causée par la sténose de l'artère sous-clavière gauche (ASCG) entraînant la réduction du débit sanguin de l'artère mammaire interne. Nous présentons deux cas de syndrome du vol coronaro-sous-clavier résultant de la sténose de l'ASCG et la réussite de leur prise en charge par pontage entre l'artère carotide gauche et l'ASCG. Compte tenu de la réussite de la prise en charge décrite dans cette observation et des limites des autres options dans le traitement du syndrome du vol coronaro-sous-clavier, le pontage entre l'artère carotide gauche et l'ASCG devrait être envisagé lors de la revascularisation des patients qui présentent le syndrome du vol coronaro-sous-clavier postopératoire en raison de la sténose de l'ASCG.

Sequential Right and Left Ventricular Assessment in Posttetralogy of Fallot Patients with Significant Pulmonary Regurgitation.

BACKGROUND: The natural history of right ventricular (RV) and left ventricular (LV) size and function among adults with tetralogy of Fallot (TOF) repair and hemodynamically significant pulmonary regurgitation (PR) is not known. The main aim of this study was to determine changes in RV and LV size and function over time in an adult population with TOF repair and hemodynamically significant pulmonary regurgitation. METHODS: Forty patients with repaired TOF and hemodynamically significant PR were included. These patients were identified on the basis of having more than one CMR between January 2008 and 2015. Patients with a prosthetic pulmonary valve or any cardiac intervention between CMR studies were excluded. Rate of progression (ROP) of RV dilation was determined for both indexed right ventricular end-systolic volume (RVESVi) and indexed right ventricular end-diastolic volume (RVEDVi), and calculated as the difference between the last and first volumes divided by the number of years between CMR#1 and CMR#2. Subjects were also divided into two groups based on the distribution of the ROP of RV dilation: Group I-rapid ROP (>50th percentile) and Group II-slower ROP (≤50th percentile). RESULTS: The interval between CMR#1 and CMR#2 was 3.9 ± 1.7 years (range 1-8 years). We did find a significant change in RVEDVi and RVESVi over this time period, although the magnitude of change was small. Nine patients (23%) had a reduction in right ventricular ejection fraction (RVEF) by greater than 5%, 13 patients (33%) had an increase in RVEDVi by greater than 10 mL/m2 and seven patients (18%) had an increase in RVESVi by greater than 10 mL/m2 . Median ROP for RVEDVi was 1.8 (range -10.4 to 21.8) mL/(m2 year); RVESVi 1.1 (range -5.8 to 24.5) mL/(m2 year) and RVEF -0.5 (range -8 to 4)%/year. Patients with a rapid ROP had significantly larger RV volumes at the time of CMR#1 and lower RVEF as compared to the slow ROP group. There was no overall significant change in LVEDVi, LVESVi, or LVEF over this time period. CONCLUSIONS: We have demonstrated, in a small population of patients with hemodynamically significant PR, that there is a small increase in RV volumes and decrease in RVEF over a mean 4-year period. We believe it to be reasonable practice to perform CMR at least every 4 years in asymptomatic patients with repaired TOF and hemodynamically significant PR. We found that LV volumes and function remained stable during the study period, suggesting that significant progressive LV changes are less likely to occur over a shorter time period. Our results inform a safe standardized approach to monitoring adults with hemodynamically significant PR post TOF repair and assist in planning allocation of this expensive and limited resource.

Comparison of image quality, and diagnostic interpretability of a new volumetric high temporal resolution scanner versus 64-slice MDCT.

We evaluated the performance of a new volume computed tomographic (CT) scanner with regards to image quality and signal homogeneity. Twenty-four subjects were prospectively enrolled. Subjects had prior imaging with rate control. Quantitative analyses performed placing regions of interest in myocardium, blood pool, and aorta. Image quality and diagnostic interpretability were assessed using Likert scales. Median heart rate was 60 and 57 bpm for volume and 64-slice coronary CT angiography (P=.02). Improvement in homogeneity was demonstrated within myocardium (30% improvement), blood pool (73%), and aorta (73%). Improvement in image quality observed at per-patient/per-segment level. Pilot study confirmed improvements in signal homogeneity and diagnostic interpretability, despite imaging at higher heart rates.

Long term prognostic utility of coronary CT angiography in patients with no modifiable coronary artery disease risk factors: Results from the 5 year follow-up of the CONFIRM International Multicenter Registry.

BACKGROUND: Coronary computed tomography angiography (coronary CTA) can prognosticate outcomes in patients without modifiable risk factors over medium term follow-up. This ability was driven by major adverse cardiovascular events (MACE). OBJECTIVE: Determine if coronary CTA could discriminate risk of mortality with longer term follow-up. In addition we sought to determine the long-term relationship to MACE. METHODS: From 12 centers, 1884 patients undergoing coronary CTA without prior coronary artery disease (CAD) or any modifiable CAD risk factors were identified. The presence of CAD was classified as none (0% stenosis), mild (1% to 49% stenosis) and obstructive (≥50% stenosis severity). The primary endpoint was all-cause mortality and the secondary endpoint was MACE. MACE was defined as the combination of death, nonfatal myocardial infarction, unstable angina, and late target vessel revascularization (>90 days). RESULTS: Mean age was 55.6 ± 14.5 years. At mean 5.6 ± 1.3 years follow-up, 145(7.7%) deaths occurred. All-cause mortality demonstrated a dose-response relationship to the severity and number of coronary vessels exhibiting CAD. Increased mortality was observed for >1 segment non-obstructive CAD (hazard ratio [HR]:1.73; 95% confidence interval [CI]: 1.07-2.79; p = 0.025), obstructive 1&2 vessel CAD (HR: 1.70; 95% CI: 1.08-2.71; p = 0.023) and 3-vessel or left main CAD (HR: 2.87; 95% CI: 1.57-5.23; p = 0.001). Both obstructive CAD (HR: 6.63; 95% CI: 3.91-11.26; p < 0.001) and non-obstructive CAD (HR: 2.20; 95% CI: 1.31-3.67; p = 0.003) predicted MACE with increased hazard associated with increasing CAD severity; 5.60% in no CAD, 13.24% in non-obstructive and 36.28% in obstructive CAD, p < 0.001 for trend. CONCLUSIONS: In individuals being assessed for CAD with no modifiable risk factors, all-cause mortality in the long term (>5 years) was predicted by the presence of more than 1 segment of non-obstructive plaque, obstructive 1- or 2-vessel CAD and 3 vessel/left main CAD. Any CAD, whether non-obstructive or obstructive, predicted MACE over the same time period.

Dynamism of the aortic annulus: Effect of diastolic versus systolic CT annular measurements on device selection in transcatheter aortic valve replacement (TAVR).

BACKGROUND: Annular dimensions, including cross-sectional area, perimeter and subsequently derived diameters, are subject to dynamic changes throughout the cardiac cycle. There is ongoing controversy as to whether perimeter measurement changes between systole and diastole are too small to impact on valve sizing. OBJECTIVES: To assess both the variability of aortic annular dimensions throughout the cardiac cycle across a range of sub-annular calcification using computed tomography (CT) and the impact of this variability on device size selection for balloon-expandable valves in a large, all-comer multi-center cohort. METHODS: ECG-gated CT data of 507 patients (mean 81 ± 7.5 years, 60.1% male) were analyzed in this retrospective, multicenter analysis. Aortic annulus dimensions were assessed on pre-specified systolic and diastolic phases by planimetry, yielding both area and perimeter. Contour smoothing was employed to avoid artificial increase in perimeter values by uneven contours. The extent of subannular calcification was graded semi-quantitatively and assessed in relation to the degree of annular dynamism. Hypothetical device sizing was undertaken to assess the impact of using systolic and diastolic measurements on valve selection. RESULTS: Mean annular dimensions were larger during systole than diastole (area: 474.4 ± 87.4 mm(2) vs. 438.3 ± 84.3 mm(2) or 8.23%, p < 0.001; perimeter: 78.5 ± 7.2 mm vs. 75.9 ± 7.2 mm or 3.36%, p < 0.001). The magnitude of annular area and perimeter change (systolic minus diastolic measurement) was greater among patients without calcification compared to patients with grade 3 calcification. Using diastolic rather than systolic data for device sizing resulted in a change of the recommended valve size in nearly half of patients for both annular area and perimeter. CONCLUSIONS: The systematic differences between systolic and diastolic annular measurements for cross-sectional area and perimeter have implications for device sizing with potential for valve under-sizing if diastolic annular dimensions are employed.

Incidence and severity of paravalvular aortic regurgitation with multidetector computed tomography nominal area oversizing or undersizing after transcatheter heart valve replacement with the Sapien 3: a comparison with the Sapien XT.

OBJECTIVES: This study sought to compare the influence of the extent of multidetector computed tomography (MDCT) area oversizing on the incidence of paravalvular aortic regurgitation (PAR) between the Sapien 3 and the Sapien XT transcatheter heart valve (THV) to define a new MDCT sizing guideline suitable for the Sapien 3 platform. BACKGROUND: The inverse relationship of PAR occurrence and oversizing has been demonstrated for the Sapien XT but the incidence of PAR with comparable oversizing with the Sapien 3 is not known. METHODS: Sixty-one prospectively enrolled patients who underwent transcatheter aortic valve replacement with the Sapien 3 THV were compared with 92 patients who underwent transcatheter aortic valve replacement with the Sapien XT THV. Patients were categorized depending on the degree of MDCT area oversizing percentage: undersizing (below 0%), 0% to 5%, 5% to 10%, and above 10%. The primary endpoint was mild or greater PAR on transthoracic echocardiography. RESULTS: Mild or greater PAR was present in 19.7% of patients (12 of 61) in the Sapien 3 group and in 54.3% of patients (50 of 92) in the Sapien XT group (p < 0.01). The Sapien 3 group, compared with the Sapien XT group, consistently demonstrated significantly lower rates of mild or greater PAR except for oversizing >10% (p for interaction = 0.54). Moderate or severe PAR rates were also lower in the Sapien 3 group than in the Sapien XT group (3.3% vs. 13.0%, p = 0.04). In the Sapien 3 group, a MDCT area oversizing percentage value of ≤4.17% was identified as the optimal cutoff value to discriminate patients with or without mild or greater PAR. CONCLUSIONS: Our retrospective analysis suggests that the Sapien 3 THV displays significantly lower rates of PAR than does the Sapien XT THV. A lesser degree of MDCT area oversizing may be employed for this new balloon-expandable THV.

Fractional flow reserve modeled from resting coronary CT angiography: state of the science.

OBJECTIVE. The purpose of this article is to discuss recent technologic innovations that enable noninvasive calculation of fractional flow reserve (FFR) from CT. CONCLUSION. FFR CT is superior to coronary CT angiography (CTA) stenosis for the diagnosis of ischemia-causing lesions. FFR CT improves the diagnostic accuracy mostly by reducing the false-positive rates incorrectly classified by CTA stenosis alone. Furthermore, in patients in whom CT shows an intermediate stenosis-wherein the results of CT alone are the most clinically ambiguous for ischemia diagnosis-FFR CT shows significantly higher diagnostic performance than CT alone.

A simplified D-shaped model of the mitral annulus to facilitate CT-based sizing before transcatheter mitral valve implantation.

BACKGROUND: The nonplanar, saddle-shaped structure of the mitral annulus has been well established through decades of anatomic and echocardiographic study. Its relevance for mitral annular assessment for transcatheter mitral valve implantation is uncertain. OBJECTIVE: Our objectives are to define the methodology for CT-based simplified "D-shaped" mitral annular assessment for transcatheter mitral valve implantation and compare these measurements to traditional "saddle-shaped" mitral annular assessment. METHODS: The annular contour was manually segmented, and fibrous trigones were identified using electrocardiogram-gated diastolic CT data sets of 28 patients with severe functional mitral regurgitation, yielding annular perimeter, projected area, trigone-to-trigone (TT) distance, and septal-lateral distance. In contrast to the traditional saddle-shaped annulus, the D-shaped annulus was defined as being limited anteriorly by the TT distance, excluding the aortomitral continuity. Hypothetical left ventricular outflow tract (LVOT) clearance was assessed. RESULTS: Projected area, perimeter, and septal-lateral distance were found to be significantly smaller for the D-shaped annulus (11.2 ± 2.7 vs 13.0 ± 3.0 cm(2); 124.1 ± 15.1 vs 136.0 ± 15.5 mm; and 32.1 ± 4.0 vs 40.1 ± 4.9 mm, respectively; P < .001). TT distances were identical (32.7 ± 4.1 mm). Hypothetical LVOT clearance was significantly lower for the saddle-shaped annulus than for the D-shaped annulus (10.7 ± 2.2 vs 17.5 ± 3.0 mm; P < .001). CONCLUSION: By truncating the anterior horn of the saddle-shaped annular contour at the TT distance, the resulting more planar and smaller D-shaped annulus projects less onto the LVOT, yielding a significantly larger hypothetical LVOT clearance than the saddle-shaped approach. CT-based mitral annular assessment may aid preprocedural sizing, ensuring appropriate patient and device selection.

Reduced iodine load with CT coronary angiography using dual-energy imaging: a prospective randomized trial compared with standard coronary CT angiography.

BACKGROUND: There is concern regarding the administration of iodinated contrast to patients with impaired renal function because of the increased risk of contrast-induced nephropathy. OBJECTIVE: Evaluate image quality and feasibility of a protocol with a reduced volume of iodinated contrast and utilization of dual-energy coronary CT angiography (DECT) vs a standard iodinated contrast volume coronary CT angiography protocol (SCCTA). METHODS: A total of 102 consecutive patients were randomized to SCCTA (n = 53) or DECT with rapid kVp switching (n = 49). Eighty milliliters and 35 mL of iodinated contrast were administered in the SCCTA and DECT cohorts, respectively. Two readers measured signal and noise in the coronary arteries; signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. A 5-point signal/noise Likert scale was used to evaluate image quality; scores of <3 were nondiagnostic. Agreement was assessed through kappa analyses. RESULTS: Demographics and radiation dose were not significantly different; there was no difference in CNR between both cohorts (P = .95). A significant difference in SNR between the groups (P = .02) lost significance (P = .13) when adjusted for body mass index. The median Likert score was inferior for DECT for reader 1 (3.6 ± 0.6 vs 4.3 ± 0.6; P < .001) but not reader 2 (4.1 ± 0.6 vs 4.3 ± 0.5; P = .06). Agreement in diagnostic interpretability in the DECT and SCCTA groups was 91% (95% confidence interval, 86%-100%) and 96% (95% confidence interval, 90%-100%), respectively. CONCLUSION: DECT resulted in inferior image quality scores but demonstrated comparable SNR, CNR, and rate of diagnostic interpretability without a radiation dose penalty while allowing for >50% reduction in contrast volume compared with SCCTA.

Recent advances in thoracic x-ray computed tomography for pulmonary imaging.

The present article reviews recent advances in pulmonary computed tomography (CT) imaging, focusing on the application of dual-energy CT and the use of iterative reconstruction. Dual-energy CT has proven to be useful in the characterization of pulmonary blood pool in the setting of pulmonary embolism, characterization of diffuse lung parenchymal diseases, evaluation of thoracic malignancies and in imaging of lung ventilation using inhaled xenon. The benefits of iterative reconstruction have been largely derived from reduction of image noise compared with filtered backprojection reconstructions which, in turn, enables the use of lower radiation dose CT acquisition protocols without sacrificing image quality. Potential clinical applications of iterative reconstruction include imaging for pulmonary nodules and high-resolution pulmonary CT.