Role of Cardiac Magnetic Resonance Imaging and Troponin T in Definitive Diagnosis of Myocardial Infarction With Nonobstructive Coronary Arteries (MINOCA)

BACKGROUND

It is unknown whether the degree of high-sensitivity troponin T (hsTropT) elevation in patients with suspected myocardial infarction without obstructive coronary arteries (MINOCA) presentations can help predict the likelihood of an abnormal cardiac magnetic resonance (CMR) scan. In this study we describe the diagnostic utility of CMR in patients with MINOCA and assesses the effect of peak hsTropT levels at presentation on CMR diagnostic yield.

METHODS

Records of consecutive patients (n = 1407) referred for CMR at a tertiary referral hospital between January 2016 and September 2021 were reviewed. A total of 70 patients met the criteria of MINOCA including ischemic chest pain, elevated peak hsTropT, and nonobstructive coronary artery disease (< 50% stenosis). The peak hsTropT levels within 72 hours of admission were identified. CMR images were generated using a 3.0 T Siemens scanner. Predictors of having an abnormal CMR were evaluated.

RESULTS

CMR established a diagnosis in 71% (n = 50) of patients, with the most common CMR diagnosis being myopericarditis (n = 27; 39%). Time to CMR was an independent predictor of a normal CMR scan (odds ratio, 0.98; 95% confidence interval, 0.97-0.999). Peak hsTropT had a high diagnostic accuracy for identifying patients with an abnormal CMR scan (area under the receiver operator characteristic curve, 0.81; P < 0.001). The optimal hsTropT cutoff was 166 ng/L, with 72% sensitivity and specificity. A troponin value ≥ 166 ng/L was independently predictive of an abnormal CMR scan (odds ratio, 4.76; 95% confidence interval, 1.32-17.11).

CONCLUSIONS

HsTropT and early CMR imaging are independently predictive of an abnormal CMR scan in patients with MINOCA. Additionally, the use of a hsTropT cutoff provides incremental predictive value to clinical parameters and time to CMR scanning in determining an abnormal scan.

Multivessel Giant Coronary Artery Aneurysms Incidentally Demonstrated During Angiography for Acute Myocardial Infarction

Giant coronary artery aneurysms are a rare manifestation of coronary artery disease and are defined by an aneurysmal diameter of >20 mm. Multimodal invasive and noninvasive imaging is required for accurate assessment We describe a case of multivessel giant coronary artery aneurysms noted during angiography for myocardial infarction. (Level of Difficulty: Intermediate.).

Cardiac manifestations of IgG4-related disease: a case series

Background

IgG4-related disease (IgG4-RD) is an autoimmune condition affecting almost every organ system, with an early inflammatory phase and later fibrotic consequences. Vascular manifestations, particularly, large-vessel involvement in IgG4-RD, are well described. However, important IgG4-related effects on medium-sized arteries and the pericardium are less well recognized. These less frequently reported cardiovascular effects of IgG4-RD include coronary artery stenosis, pericardial disease, cardiac masses, and valvular heart disease.

Case summary

This case series focuses on three patients that demonstrate the cardiovascular effects of IgG4-RD and the pitfalls and importance of early diagnosis. Cases 1 and 2 presented with cardiac manifestations prior to more typical organ systems being affected which led to a delay in diagnosis. Case 1 presented with an acute myocardial infarction secondary to IgG4-RD of the coronary arteries and Case 2 presented with pericarditis which progressed to pericardial constriction due to IgG4-RD. Case 3 already had a diagnosis of IgG4-RD from a prior renal biopsy which raised the index of suspicion that his pericardial disease and thoracic mass were also related to IgG4-RD.

Discussion

Cardiac manifestations of IgG4-RD remain under-recognized and include coronary artery and pericardial disease. These manifestations often precede more typical manifestations in other organ systems. Recognizing cardiac manifestations of IgG4-RD on cardiac imaging can raise clinical suspicion and act as a catalyst to ascertain a confirmatory diagnosis. Early diagnosis and treatment are crucial to prevent potentially fatal outcomes and irreversible fibrosis.

Aspirin and Statin Therapy for Nonobstructive Coronary Artery Disease: Five-year Outcomes from the CONFIRM Registry

Purpose

In this cohort study, 5-year data from the Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry (ie, CONFIRM) were examined to identify associations of baseline aspirin and statin use with mortality, major adverse cardiovascular events (MACE), and myocardial infarction (MI) in individuals without substantial (≥50%) stenosis.

Materials and Methods

In this prospective cohort study, all participants in the registry underwent coronary CT angiography and were classified as having no detectable coronary plaque or having nonobstructive coronary artery disease (CAD) (1%-49% stenosis). Participants with obstructive (≥50%) stenosis were excluded from analysis. The study commenced in June 2003 and was completed in March 2016. All unadjusted and risk-adjusted analyses utilized the Cox proportional hazard model with hospital sites modeled using shared frailty.

Results

A total of 6386 participants with no detectable plaque or with nonobstructive CAD were included (mean age, 56.0 years ± 13.3 [SD], 52% men). The mean follow-up period was 5.66 years ± 1.10. Nonobstructive CAD (n = 2815, 44% of all participants included in the study) was associated with a greater risk of all-cause mortality (10.6% [298 of 2815] vs 4.8% [170 of 3571], P < .001) compared to those without CAD (n = 3571, 56%). Baseline aspirin and statin use was documented for 1415 and 1429 participants, respectively, with nonobstructive CAD, and for 1560 and 1565 participants without detectable plaque, respectively. In individuals with nonobstructive CAD, baseline aspirin use was not associated with a reduction in MACE (10.9% [102 of 936] vs 14.7% [52 of 355], P = .06), all-cause mortality (9.6% [95 of 991] vs 10.9% [46 of 424], P = .468), or MI (4.4% [41 of 936] vs 6.2% [22 of 355], P = .18). On multivariate risk-adjusted analysis, baseline statin use was associated with a lower rate of MACE (hazard ratio, 0.59; 95% CI: 0.40, 0.87; P = .007). Neither therapy improved clinical outcomes for participants with no detectable plaque.

Conclusion

In participants with nonobstructive CAD, baseline use of statins, but not of aspirin, was associated with improved clinical outcomes. Neither therapy was associated with benefit in participants without plaque.Keywords: Aspirin, Statin, Coronary Artery Disease, CT Angiography, Nonobstructive Coronary Artery DiseaseClinical trial registration no. NCT01443637 Supplemental material is available for this article. © RSNA, 2022See also the commentary by Canan and Navar in this issue.

Incidentally identified coronary artery calcium on non-contrast CT scan of the chest predicts major adverse cardiac events among hospital inpatients

BACKGROUND

Coronary artery calcium (CAC) identified on non-gated CT scan of the chest is predictive of major adverse cardiac events (MACE) in multiple studies with guidelines therefore recommending the routine reporting of incidental CAC. These studies have been limited however to the outpatient setting. We aimed to determine the prognostic utility of incidentally identified CAC on CT scan of the chest among hospital inpatients.

METHODS AND RESULTS

Consecutive patients (n=740) referred for inpatient non-contrast CT scan of the chest at a tertiary referral hospital (January 2011 to March 2017) were included (n=280) if they had no known history of coronary artery disease, active malignancy or died within 30 days of admission. Scans were assessed for the presence of CAC by visual assessment and quantified by Agatston scoring. Median age was 69 years (IQR: 54-82) and 51% were male with a median CAC score of 7 (IQR 0-205). MACE occurred in 140 (50%) patients at 3.5 years median follow-up including 98 deaths. Half of all events occurred within 18 months. Visible CAC was associated with increased MACE (HR) 6.0 (95% CI: 3.7 to 9.7) compared with patients with no visible CAC. This finding persisted after adjusting for cardiovascular risk factors HR 2.4 (95% CI: 1.3 to 4.3) and with both absolute CAC score and CAC score ≥50th percentile.

CONCLUSION

Incidental CAC identified on CT scan of the chest among hospital inpatients provides prognostic information that is independent of cardiovascular risk factors. These patients may benefit from aggressive risk factor modification given the high event rate in the short term.

Novel pressure-regulated deployment strategy for improving the safety and efficacy of balloon-expandable transcatheter aortic valves

Background

The optimal method for balloon-expandable transcatheter heart valve (THV) deployment remains unknown. Current implantation protocols are volume-dependent and rely on ad-hoc filling of the deployment apparatus without accounting for annular wall tension during prosthesis expansion, predisposing patients to inconsistent clinical outcomes. During THV deployment, the annular wall tension exerted by the expanding prosthesis is determined by prosthesis diameter and balloon pressure (Laplace's Law).

Objective

We proposed and tested a novel method for balloon-expandable THV deployment, aimed at controlling balloon pressure and the resulting annular wall tension to allow optimal prosthesis-annulus apposition while preventing significant tissue injury.

Methods

330 consecutive patients with severe native aortic stenosis who underwent balloon-expandable THV implantation between 2015–2020 were included. 106 patients were considered high-risk for annular rupture. THVs were deployed until reaching a pre-determined balloon pressure; 4–4.5atm in earlier cases to establish experience and safety, later increasing to 5–6.5atm in most cases. Post-dilatation was performed to reduce &gt;mild angiographic regurgitation (PVR). Using a biomechanical model, annular wall stress (tension) was estimated for each case and assessed against recorded rates of post-dilatation, ≥mild paravalvular regurgitation (PVR) on TTE, new PPM or LBBB and annular rupture.

Results

Patients with wall stress &gt;3MPa (n=184) had reduced post-dilatation rate (p&lt;0.001) and final PVR (≥mild, p=0.014). Annular rupture occurred in 2/3 high-risk cases with wall stress &gt;3.5MPa; no rupture occurred in 102 high-risk cases with wall stress ≤3.5MPa. Based on these results, we defined target deployment wall stress levels (3–3.5MPa) and associated deployment pressure per THV size. Patients within this target range (n=136) had 8.1% new PPM, 12.5% new LBBB, 12.7% mild PVR with no cases of ≥moderate PVR. Importantly, there was an inconsistent relationship between deployment balloon volume and resulting annular wall stress.

Conclusion

Pressure-regulated THV deployment is a simple, easily reproducible, safe and effective method, regardless of high-risk anatomical complexities.

Funding Acknowledgement

Type of funding sources: None. Annular wall stress and PVRModel, stress vs volume and new strategy

A novel pressure-regulated deployment strategy for improving the safety and efficacy of balloon-expandable transcatheter aortic valves

Background

Annular rupture is a catastrophic complication of Transcatheter Aortic Valve Implantation, more commonly seen with balloon expandable valves. Size selection and deployment of these valves often presents a serious challenge as prosthesis oversizing increases the risk of rupture, while undersizing results in greater paravalvular regurgitation (PVR). Current deployment protocols are volume-regulated and susceptible to undesired prosthesis over or under-expansion. Laplace's Law demonstrates that the stress exerted on the aortic wall is determined by both the valve area and internal pressure during deployment. Yet the issue of balloon pressure during deployment has been thus far ignored.

Purpose

In this feasibility study, we aimed to develop a novel pressure-regulated deployment method that allows optimising apposition between valve and annulus, while preventing significant tissue injury and rupture.

Methods

We analysed a cohort of 278 consecutive patients with severe aortic stenosis and intermediate-severe surgical risk who underwent TAVI using Sapien 3 valves. This included 88 patients (32%) considered at high risk of annular rupture based on accepted factors such as moderate-severe subannular calcification. A pressure gauge was connected to the apparatus and in each case the valve was deployed until reaching a pre-determined pressure limit. In earlier cases lower pressures of 4–4.5atm were used to establish safety, while in later cases pressure limit was increased to maximum of 7atm. In some patients post-dilatation was performed to improve angiographic regurgitation. Using a biomechanical application of Laplace's Law, the estimated annular wall stress was calculated for each case and assessed against recorded complications such as annular rupture, PPM insertion, new LBBB and PVR on post-procedure TTE. Based on these analyses we then determined the optimal pressure limit for each available valve size.

Results

Distribution of deployment pressures and associated estimated wall stress are shown in attached Figure. 1 case of annular rupture (0.4%) occurred in high risk patient at 3.81MPa. Wall stress levels &gt;3.0MPa were associated with reduced rates of post dilatation (13% vs 37%, p&lt;0.001) and ≥mild PVR (10.7% vs 20%, p=0.093). In patients (148) with estimated wall stress between 3–3.8MPa rates of new PPM and LBBB were 7.4% and 8.1%, respectively. Greater wall stress was not associated with increased new PPM/LBBB risk. Therefore, we suggest the optimal deployment pressure limit to minimise risk of rupture, rates of post-dilatation and clinically significant PVR is: 6atm for 23mm valves, 5.5atm for 26mm valves and 5atm for 29mm valves.

Conclusion

Pressure-regulated deployment strategy is a reproducible, safe and effective method for balloon expandable TAVI, alleviating concerns of valve oversizing in high risk patients. Further trials are needed to validate this novel method and compare it with current volume-regulated techniques.

Abstract Figures

Funding Acknowledgement

Type of funding source: None

Reduction in radiation exposure in cardiovascular computed tomography imaging: results from the PROspective multicenter registry on radiaTion dose Estimates of cardiac CT angIOgraphy iN daily practice in 2017 (PROTECTION VI)

Aims

Advances of cardiac computed tomography angiography (CTA) have been developed for dose reduction, but their efficacy in clinical practice is largely unknown. This study was designed to evaluate radiation dose exposure and utilization of dose-saving strategies for contrast-enhanced cardiac CTA in daily practice.

Methods and results

Sixty one hospitals from 32 countries prospectively enrolled 4502 patients undergoing cardiac CTA during one calendar month in 2017. Computed tomography angiography scan data and images were analysed in a central core lab and compared with a similar dose survey performed in 2007. Linear regression analysis was performed to identify independent predictors associated with dose. The most frequent indication for cardiac CTA was the evaluation of coronary artery disease in 89% of patients. The median dose-length product (DLP) of coronary CTA was 195 mGy*cm (interquartile range 110-338 mGy*cm). When compared with 2007, the DLP was reduced by 78% (P < 0.001) without an increase in non-diagnostic coronary CTAs (1.7% in 2007 vs. 1.9% in 2017 surveys, P = 0.55). A 37-fold variability in median DLP was observed between the hospitals with lowest and highest DLP (range of median DLP 57-2090 mGy*cm). Independent predictors for radiation dose of coronary CTA were: body weight, heart rate, sinus rhythm, tube voltage, iterative image reconstruction, and the selection of scan protocols.

Conclusion

This large international radiation dose survey demonstrates considerable reduction of radiation exposure in coronary CTA during the last decade. However, the large inter-site variability in radiation exposure underlines the need for further site-specific training and adaptation of contemporary cardiac scan protocols.

Long-term prognostic utility of computed tomography coronary angiography in older populations

Aims

The long-term prognostic value of coronary computed tomography angiography (CCTA)-identified coronary artery disease (CAD) has not been evaluated in elderly patients (≥70 years). We compared the ability of coronary CCTA to predict 5-year mortality in older vs. younger populations.

Methods and results

From the prospective CONFIRM (COronary CT Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multicenter) registry, we analysed CCTA results according to age <70 years (n = 7198) vs. ≥70 years (n = 1786). The severity of CAD was classified according to: (i) maximal stenosis degree per vessel: none, non-obstructive (1–49%), or obstructive (>50%); (ii) segment involvement score (SIS): number of segments with plaque. Cox-proportional hazard models assessed the relationship between CCTA findings and time to mortality. At a mean 5.6 ± 1.1 year follow-up, CCTA-identified CAD predicted increased mortality compared with patients with a normal CCTA in both <70 years [non-obstructive hazard ratio (HR) confidence interval (CI): 1.70 (1.19–2.41); one-vessel: 1.65 (1.03–2.67); two-vessel: 2.24 (1.21–4.15); three-vessel/left main: 4.12 (2.27–7.46), P < 0.001] and ≥70 years [non-obstructive: 1.84 (1.15–2.95); one-vessel: HR (CI): 2.28 (1.37–3.81); two-vessel: 2.36 (1.33–4.19); three-vessel/left main: 2.41 (1.33–4.36), P = 0.014]. Similarly, SIS was predictive of mortality in both <70 years [SIS 1–3: 1.57 (1.10–2.24); SIS ≥4: 2.42 (1.65–3.57), P < 0.001] and ≥70 years [SIS 1–3: 1.73 (1.07–2.79); SIS ≥4: 2.45 (1.52–3.93), P < 0.001]. CCTA findings similarly predicted long-term major adverse cardiovascular outcomes (MACE) (all-cause mortality, myocardial infarction, and late revascularization) in both groups compared with patients with no CAD.

Conclusion

The presence and extent of CAD is a meaningful stratifier of long-term mortality and MACE in patients aged <70 years and ≥70 years old. The presence of obstructive and non-obstructive disease and the burden of atherosclerosis determined by SIS remain important predictors of prognosis in older populations.

Feeding Induces Left Atrial Compression and Impedes Cardiac Filling in Patients With Large Hiatal Hernia

BACKGROUND

Patients with large hiatal hernias (HH) frequently experience postprandial dyspnea. The aim of this study was to evaluate whether feeding induced cardiac compression in these patients using echocardiography.

METHODS

Transthoracic echocardiography was performed during fasting and 30 min after feeding (300 g rice pudding) in patients with HHs (n = 32; mean age, 72 ± 9 years). A subset of patients (n = 15; mean age, 76 ± 6 years) were evaluated postoperatively.

RESULTS

Preoperatively, feeding decreased left atrial (LA) volumes (maximal 27.4 ± 11.3 vs 19.2 ± 9.7 mL/m², P < .001; minimal 13.1 ± 7.0 vs 6.9 ± 5.1 mL/m², P < .001), and increased LA inflow velocities (systolic wave 0.62 ± 0.14 vs 0.77 ± 0.17 m/sec, P < .01; diastolic wave 0.46 ± 0.13 vs 0.59 ± 0.13 m/sec, P < .01), mitral inflow velocities (E wave 0.79 ± 0.17 vs 0.94 ± 0.19 m/sec, P < .01; A wave 0.93 ± 0.20 vs 1.05 ± 0.22 m/sec, P < .01), and E/E' ratio (12.1 ± 2.7 vs 13.7 ± 3.9, P < .01). Cardiac output (6.3 ± 1.6 vs 7.24 ± 2.0 L, P < .01) increased postprandially by marked heart rate augmentation (68.8 ± 7.0 vs 84.2 ± 8.4 beats/min, P < .01), with modest stroke volume increase (88.5 ± 16.7 vs 94.3 ± 19.5 mL, P = .03). After HH surgery, feeding did not change LA volumes (maximal 52.9 ± 13.6 vs 53.4 ± 12.5 mL, P = .89; minimal 28.6 ± 12.2 vs 27.4 ± 8.7 mL, P = .59) or E/E' ratio (10.9 ± 2.1 vs 11.3 ± 2.3) and induced more modest alterations in LA inflow (systolic wave 0.58 ± 0.17 vs 0.68 ± 0.16 m/sec, P = .01; diastolic wave 0.41 ± 0.12 vs 0.47 ± 0.13 m/sec, P = .01) and mitral inflow (E wave 0.69 ± 0.15 vs 0.80 ± 0.13 m/sec, P < .01; A wave 0.92 ± 0.13 vs 1.01 ± 0.18 m/sec, P = .02). Postoperatively, feeding increased cardiac output by substantial stroke volume augmentation (81.9 ± 16.5 vs 90.8 ± 16.0 mL, P = .01), with only modest increase in heart rate (69.8 ± 9.1 vs 75.9 ± 10.5 beats/min, P < .01).

CONCLUSIONS

Feeding produces marked LA compression in patients with HHs, inducing compensatory exaggerated responses in cardiac inflow and hemodynamic status. These compensatory mechanisms improve postoperatively following resolution of LA compression, likely explaining the debility noted preoperatively.

Left atrial compression and right ventricular outflow tract diameter on echocardiography are independently associated with exercise capacity in patients with large hiatal hernia

INTRODUCTION

Large hiatal hernia (HH) is often associated with left atrial (LA) compression, anteroposterior cardiac compression (manifesting as reduced right ventricular outflow tract (RVOT) diameter), and left ventricular (LV) compression (manifesting as systolic paradoxical outward motion (LV-PM) of the posterobasal LV segment). Exercise impairment, also common in this population, improves following HH surgery. We aimed to identify echocardiographic parameters independently associated with exercise impairment due to HH-mediated cardiogenic compression.

METHODS

Patients with a large HH (>30% intra-thoracic stomach, n = 163) referred for cardiac evaluation were included. Echocardiographic parameters were retrospectively analyzed in relation to HH-related LA compression severity and the presence of LV-PM. Echocardiographic parameters independently associated with exercise capacity were identified by multivariable analysis.

RESULTS

Mean baseline metabolic equivalents were reduced (70 ± 28% predicted). Moderate-severe LA compression and LV-PM were present in 91 of 163 (56%) and 65 of 162 (40%) patients, respectively. Patients with moderate-severe LA compression and LV-PM had decreased LA and LV dimensions. Moderate-severe LA compression was also associated with reduced RVOT diameter while LV-PM predicted a greater reduction in LV volumes. LA compression and RVOT diameter were independently associated with baseline exercise capacity and increased following HH surgery performed in a subgroup (n = 72, LA diameter: 14 ± 5 vs 20 ± 4 mm/m² ; RVOT diameter: 17 ± 3 vs 19 ± 3 mm/m² , P < .001 for both). Conversely, LV-PM was not independently associated with exercise capacity.

CONCLUSION

Hiatal hernia-related cardiac compression reduces LA and RVOT dimensions. These parameters are independently associated with baseline exercise capacity and improve following HH surgery. LV-PM is associated with decreased LV volumes but not exercise capacity in this population.

Valsalva maneuver exacerbates left atrial compression in patients with large hiatal hernia

INTRODUCTION

Hiatal hernia (HH) can cause left atrial (LA) compression and impair LA filling. We evaluated the cardiac effects of preload reduction and abdominal strain induced by Valsalva maneuver (VM) in large HH patients.

METHODS

LA and left ventricular (LV) dimensions were measured using 2D transthoracic echocardiography at rest and during VM in HH patients (n=55, 70±10 years) and controls (n=22, 67±6 years). Biplane LV volumes (n=39) and mitral inflow pulse-wave Doppler parameters (n=27) were also evaluated. In HH patients, resting LA compression was graded qualitatively (none-mild or moderate-severe).

RESULTS

In both controls and HH patients, VM significantly decreased LA (controls, 19±2 vs 16±3 mm/m² ; HH, 16±5 vs 9±5 mm/m² ) and LV diameters (22±3 vs 19±3 mm/m² ; 21±3 vs 17±3 mm/m² ) and LV volume (38±8 vs 26±10 mL/m² ; 31±8 vs 19±9 mL/m² ) (P<.001 for all). VM decreased LA diameter significantly more in HH patients than controls (-42% vs -16%, P<.001). HH patients with none-mild resting LA compression exhibited significantly greater LA diameter reduction than controls (-38±23% vs -16±13% P=.0003) despite similar resting LA diameters. LV volumes were similarly decreased by VM in HH patients and controls irrespective of resting LA compression severity indicating relative preservation of LV filling. LA diameter correlated inversely with early diastolic filling velocity during VM in HH patients (R=-.43, P=.03) but not controls (R=.18, P=.43).

CONCLUSION

VM can markedly exacerbate LA compression in HH patients; however, LV filling is relatively less affected possibly due to augmented early diastolic filling. Conditions associated with decreased preload and increased intra-abdominal pressure may exacerbate the cardiac effects of large HH.

Predictive Value of Age- and Sex-Specific Nomograms of Global Plaque Burden on Coronary Computed Tomography Angiography for Major Cardiac Events

BACKGROUND

Age-adjusted coronary artery disease (CAD) burden identified on coronary computed tomography angiography predicts major adverse cardiovascular event (MACE) risk; however, it seldom contributes to clinical decision making because of a lack of nomographic data. We aimed to develop clinically pragmatic age- and sex-specific nomograms of CAD burden using coronary computed tomography angiography and to validate their prognostic use.

METHODS AND RESULTS

Patients prospectively enrolled in phase I of the CONFIRM registry (Coronary CT Angiography Evaluation for Clinical Outcomes) were included (derivation cohort: n=21,132; 46% female) to develop CAD nomograms based on age-sex percentiles of segment involvement score (SIS) at each year of life (40-79 years). The relationship between SIS age-sex percentiles (SIS%) and MACE (all-cause death, myocardial infarction, unstable angina, and late revascularization) was tested in a nonoverlapping validation cohort (phase II, CONFIRM registry; n=3030, 44% female) by stratifying patients into 3 SIS% groups (≤50th, 51-75th, and >75th) and comparing annualized MACE rates and time to MACE using multivariable Cox proportional hazards models adjusting for Framingham risk and chest pain typicality. Age-sex percentiles were well fitted to second-order polynomial curves (men: R²=0.86±0.12; women: R²=0.86±0.14). Using the nomograms, there were 1576, 965, and 489 patients, respectively, in the ≤50th, 51-75th, and >75th SIS% groups. Annualized event rates were higher among patients with greater CAD burden (2.1% [95% confidence interval: 1.7%-2.7%], 3.9% [95% confidence interval: 3.0%-5.1%], and 7.2% [95% confidence interval: 5.4%-9.6%] in ≤50th, 51-75th, and >75th SIS% groups, respectively; P<0.001). Adjusted MACE risk was significantly increased among patients in SIS% groups above the median compared with patients below the median (hazard ratio [95% confidence interval]: 1.9 [1.3-2.8] for 51-75th SIS% group and 3.4 [2.3-5.0] for >75th SIS% group; P<0.01 for both).

CONCLUSIONS

We have developed clinically pragmatic age- and sex-specific nomograms of CAD prevalence using coronary computed tomography angiography findings. Global plaque burden measured using SIS% is predictive of cardiac events independent of traditional risk assessment.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01443637.

Three-Dimensional Echocardiography Compared With Computed Tomography to Determine Mitral Annulus Size Before Transcatheter Mitral Valve Implantation

BACKGROUND

Previously, through the use of computed tomography (CT), it has been proposed that D-shaped versus saddle-shaped mitral annulus (MA) segmentation is more biomechanically appropriate to determine transcatheter mitral valve implantation size and eligibility.

METHODS AND RESULTS

Forty-one patients with severe mitral regurgitation being considered for transcatheter mitral valve implantation who had undergone cardiac CT and 3-dimensional transesophageal echocardiography (3D-TEE) were retrospectively evaluated. A standardized segmentation protocol for the D-shaped MA was developed using Philips Q-Laboratory mitral valve quantification software. MA dimensions were compared using Spearman's rank correlation and Bland-Altman analysis. Inter- and intraobserver agreement was quantified by intraclass correlation coefficient and Bland-Altman analysis. Mean age was 77±14 years; 71% male (n=29); mitral regurgitation pathogenesis was functional in 54% (n=22) and myxomatous in 46% (n=19). Mean MA area and circumference by 3D-TEE and CT were 11.3±2.7 versus 11.4±3.0 (P=0.67) and 124.1±15.6 versus 123.9±15.5 (P=0.79), respectively, with excellent correlation between modalities (r=0.84 and r=0.86; P<0.0001) and no systematic bias (-0.20±1.8 cm(2) [-3.7 cm(2); 3.3 cm(2)], 0.37±9 mm [-18.0 mm; 17.27 mm]). Mean septal-to-lateral and inter-trigone distances by 3D-TEE and CT were 33.2±4.7 versus 32.5±4.4 (P=0.24) and 31.7±3.5 versus 32.6±3.6 (P=0.06), respectively, with good correlation (r=0.69 and r=0.71; P<0.0001) and no systematic bias (0.77±3.8 mm [-6.7 mm; 8.2 mm], -1.5±3.1 mm [-4.6 mm; 7.6 mm]). There was excellent intra- and interobserver agreement according to intraclass correlation coefficients >0.90 for all parameters.

CONCLUSIONS

Similar to cardiac CT, 3D-TEE allows for D-shaped MA segmentation with no systematic difference in MA dimensions between modalities. This study supports the utilization of 3D-TEE as a complementary tool to CT assessment of the D-shaped MA to determine transcatheter mitral valve implantation size.

Left ventricular access point determination for a coaxial approach to the mitral annular landing zone in transcatheter mitral valve replacement

INTRODUCTION

To facilitate coaxial device deployment in transcatheter mitral valve replacement (TMVR), a coaxial approach to the mitral annular plane is needed. We sought to establish a method to determine an 'orthogonal' left ventricular (LV) access point for transapical TMVR and to quantitatively characterize its location in patients with severe mitral regurgitation using cardiac computed tomography.

METHODS

Cardiac CT data sets of 54 patients with moderate-severe mitral regurgitation evaluated for potential TMVR were analyzed. The D-shaped mitral annular contour was segmented and a 2-dimensional annular plane was derived, allowing for subsequent definition of the perpendicularly oriented mitral annular trajectory. The 'orthogonal' LV access point was defined as the transection point of mitral trajectory with the LV epicardial surface. The location of the access point was quantified by its epicardial distance from the true apex and by the rotational offset from a 3-chamber view.

RESULTS

LV access points orthogonal to the mitral annular plane were most frequently located in the anterolateral (n = 22, 40.7%) and anterior (n = 16, 29.6%), less frequently anteroseptal (n = 6, 11.1%) and inferolateral (n = 5, 9.3%) ventricular segment; none inferior or inferoseptal. The mean distance to the LV apex was 17.6 ± 7.7 mm. The mean forward rotational offset from the 3-chamber view was 96.4 ± 43.4°, relating to a mean forward rotational offset of 6.4 ± 43.4° in regard to a hypothetical, secondary 90° x-plane view. No significant difference between patients with degenerative mitral valve disease or functional mitral regurgitation was observed.

CONCLUSION

The location of the LV access point that provides an orthogonal trajectory to the mitral annular plane exhibits relevant inter-individual variability. It is commonly not identical with the true apex, and frequently localized in the anterolateral or anterior ventricular segments.

Cardiac Computed Tomography and Magnetic Resonance Imaging in the Evaluation of Mitral and Tricuspid Valve Disease

Transcatheter interventions to treat mitral and tricuspid valve disease are becoming increasingly available because of the growing number of elderly patients with significant comorbidities or high operative risk. Thorough clinical and imaging evaluation in these patients is essential. The latter involves both characterization of the mechanism and severity of valvular disease as well as determining the hemodynamic consequences and extent of ventricular remodeling, which is an important predictor of future outcomes. Moreover, an assessment of the suitability and risk of complications associated with device-specific therapies is also an important component of the preprocedural evaluation in this cohort. Although echocardiography including 2-dimensional and 3-dimensional methods has an important role in the initial assessment and procedural guidance, cross-sectional imaging, including both computed tomographic imagning and cardiac magnetic resonance imaging, is increasingly being integrated into the evaluation of mitral and tricuspid valve disease. In this review, we discuss the role of cross-sectional imaging in mitral and tricuspid valve disease, primarily valvular regurgitation assessment, with an emphasis on the preprocedural evaluation and implications for transcatheter interventions.

Computed tomography assessment for transcatheter aortic valve in valve implantation: The vancouver approach to predict anatomical risk for coronary obstruction and other considerations

Valve-in-valve implantation of a transcatheter heart valve into a failed bioprosthetic heart valve has emerged as a treatment alternative to repeat conventional surgery. This requires careful pre-procedural assessment using non-invasive imaging to identify patients at risk for procedure related adverse events, such as ostial coronary occlusion. Herein we report how to comprehensively assess aortic root anatomy using computed tomography prior to transcatheter valve implantation for failed bioprosthetic aortic valves.

Long-Term Prognostic Utility of Coronary CT Angiography in Stable Patients With Diabetes Mellitus

OBJECTIVES

The goal of this study was to determine the long-term prognostic value of coronary computed tomography angiography (CTA) among patients with diabetes mellitus (DM) compared with nondiabetic subjects.

BACKGROUND

The long-term prognostic value of coronary CTA in patients with DM is not well established.

METHODS

Patients enrolled in the CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter) registry with 5-year follow-up data were identified. The extent and severity of coronary artery disease (CAD) were analyzed at baseline coronary CTA and in relation to outcomes between diabetic and nondiabetic patients. CAD according to coronary CTA was defined as none (0% stenosis), nonobstructive (1% to 49% stenosis), or obstructive (≥50% stenosis). Time to death (and in a subgroup, time to major adverse cardiovascular event) was estimated by using multivariable Cox proportional hazards models.

RESULTS

A total of 1,823 patients were identified as having DM with 5-year clinical follow-up and were propensity-matched to 1,823 patients without DM (mean age 61.8 ± 10.9 years; 54.4% male). Patients with DM did not exhibit a heightened risk of death compared with the propensity-matched nondiabetic subjects in the absence of CAD on coronary CTA (risk-adjusted hazard ratio [HR] of DM: 1.32; 95% confidence interval [CI]: 0.78 to 2.24; p = 0.296). Patients with DM were at increased risk of dying compared with nondiabetic subjects in the setting of nonobstructive CAD (in the propensity-matched cohort: HR, 2.10; 95% CI: 1.43 to 3.09; p < 0.001) with a mortality risk greater than nondiabetic subjects with obstructive disease (p < 0.001). In a risk-adjusted hazard analysis among patients with DM, both per-patient obstructive CAD and nonobstructive CAD conferred an increase in all-cause mortality risk compared with patients without atherosclerosis on coronary CTA (nonobstructive disease-HR: 2.07; 95% CI: 1.33 to 3.24; p = 0.001; obstructive disease-HR: 2.22; 95% CI: 1.47 to 3.36; p < 0.001).

CONCLUSIONS

Among patients with DM, nonobstructive and obstructive CAD according to coronary CTA were associated with higher rates of all-cause mortality and major adverse cardiovascular events at 5 years, and this risk was significantly higher than in nondiabetic subjects. Importantly, patients with DM without CAD according to coronary CTA were at a risk comparable to that of nondiabetic subjects.

The effect of a whole heart motion-correction algorithm on CT image quality and measurement reproducibility in Pre-TAVR aortic annulus evaluation

BACKGROUND

Motion correction (MC) algorithms have been shown to improve image quality, interpretability and diagnostic accuracy in coronary CT angiography. We sought to determine whether MC extended to the whole heart would demonstrate improved image quality and reproducibility of aortic annular measurements in pre-TAVR CT.

MATERIALS AND METHODS

Twenty-two consecutive contrast enhanced CT data sets acquired for pre TAVR evaluation using retrospective ECG synchronization during a single heart beat were retrospectively identified. Image data sets were obtained from raw data acquired at 35% and 75% of the R-R interval using both standard (STD) and motion corrected (MC) reconstruction algorithms. Four data sets (2 STD, 2 MC) per patient were analyzed by 2 independent, blinded readers for aortic annular area, short and long axis, perimeter and average diameter. Image quality was graded using a 5 point Likert score (1 and 2 non diagnostic, 5 excellent). Statistical analysis was performed using Wilcoxon matched paired tests, Bland-Altman (B-A) plots and Lin's concordance coefficient comparing 35% STD to 35% MC, and 75% STD to 75% MC.

RESULTS

Eighty-eight datasets were analyzed (44 STD, 44 MC). At 35%, there was a significant improvement in image quality for MC (Likert score 3.3 ± 0.9 STD vs. 3.9 ± 0.7 MC, p < 0.007). While B-A analysis demonstrated narrower interobserver agreement for aortic annular area (bias 0.03 vs 0.02 cm(2), range -0.32 to 0.39 cm(2) vs -0.50 to 0.55 cm(2)), and perimeter (bias 0.3 vs 0.3 mm, range -3.1 to 3.8 mm vs -4.6 to 5.3 mm), this was not statistically significant by concordance correlation coefficient. At 75%, there was no significant difference in image quality (Likert score 3.3 ± 0.9 vs. 3.5 ± 0.76, p = 0.454) or annular measurement agreement intervals.

CONCLUSION

Motion correction algorithms may yield significant improvements of image quality in systolic CT data sets of the heart. Further validation studies are required to determine the effect on annular measurements and translation into clinical practice.

Comparison of Rates of Coronary Angiography and Combined Testing Procedures in Patients Seen in the Emergency Room With Chest Pain (But No Objective Acute Coronary Syndrome Findings) Having Coronary Computed Tomography Versus Exercise Stress Testing

Coronary computed tomography angiography (CCTA) appears comparable to standard care, including exercise stress testing (EST), in diagnosing acute coronary syndrome in emergency department (ED) patients with chest pain but may increase downstream testing. The objective of this study was to investigate rates of post-CCTA versus post-EST testing for (1) invasive angiography and (2) all combined cardiac testing. This was a retrospective cohort study performed at 2 urban Canadian EDs involving patients aged up to 65 years with chest pain but no objective ACS findings that were evaluated with CCTA or EST at the physician's discretion. The primary outcome was the proportion of patients who had 30-day invasive angiography in each group; secondary outcomes included all subsequent 30-day cardiac testing, including nuclear medicine scanning. From July 1, 2012, to June 30, 2014, we collected 1,700 patients: 521 CCTA and 1,179 EST. Demographics and risk factors were similar in both cohorts. In the following 30 days, 30 CCTA (5.8%) and 297 EST (25.2%) patients underwent any type of additional cardiac testing (difference 19.4%, 95% CI 16.0 to 22.6), whereas 12 CCTA (2.3%) and 20 EST patients (1.7%) underwent angiography (difference 0.6%, 95% CI -0.8% to 2.6%). No patients in either group died or had a myocardial infarction within 30 days. For ED patients with chest pain who underwent brief observation, CCTA and EST had similar 30-day angiography rates, but CCTA patients underwent significantly less overall cardiac investigations.

Beyond Stenosis With Fractional Flow Reserve Via Computed Tomography and Advanced Plaque Analyses for the Diagnosis of Lesion-Specific Ischemia

In the treatment of stable coronary artery disease (CAD), the determination of stenosis severity by invasive coronary angiography (ICA) is a critical procedure, and for borderline lesions, the detection of ischemia through invasive fractional flow reserve (FFR) is the gold standard. With advances in computational fluid dynamics, FFR can now be calculated noninvasively using anatomic data from coronary computed tomographic angiography (CCTA). This technique is known as FFR_CT. The purpose of this review is to summarize the science of FFR_CT, describe its diagnostic accuracy, discuss its clinical and economic impact, and elucidate factors beyond stenosis severity that may mechanistically relate to lesion-specific ischemia. These factors include adverse atherosclerotic plaque characteristics such as positive remodelling, low-attenuation plaque, and spotty calcification, as well as aggregate plaque volume. These factors can be appreciated noninvasively by CCTA but not by ICA. The diagnostic accuracy of FFR_CT, compared with the gold standard of FFR, has been validated in 3 prospective multicentre blinded core laboratory-controlled trials, and as a result FFR_CT has been approved by the US Food and Drug Administration for clinical use. FFR_CT has also been shown in a clinical utility trial to better identify patients without obstructive CAD when compared with standard noninvasive assessment of stable CAD, thereby avoiding unnecessary angiograms. In addition, the use of FFR_CT has been shown to allow for a significant cost savings compared with traditional care. It is therefore important for cardiologists to appreciate the value of this important new methodology.

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.

Safety and efficiency of outpatient versus emergency department-based coronary CT angiography for evaluation of patients with potential ischemic chest pain

BACKGROUND

While coronary CT angiography (coronary CTA) may be comparable to standard care in diagnosing acute coronary syndrome (ACS) in emergency department (ED) chest pain patients, it has traditionally been obtained prior to ED discharge and a strategy of delayed outpatient coronary CTA following an ED visit has not been evaluated.

OBJECTIVE

To investigate the safety of discharging stable ED patients and obtaining outpatient CCTA.

METHODS

At two urban Canadian EDs, patients up to 65 years with chest pain but no findings indicating presence of ACS were further evaluated depending upon time of presentation: (1) ED-based coronary CTA during normal working hours, (2) or outpatient coronary CTA within 72 hours at other times. All data were collected prospectively. The primary outcome was the proportion of patients who had an outpatient coronary CTA ordered and had a predefined major adverse cardiac event (MACE) between ED discharge and outpatient CT; secondary outcome was the ED length of stay in both groups.

RESULTS

From July 1, 2012 to June 30, 2014, we enrolled 521 consecutive patients: 350 with outpatient CT and 171 with ED-based CT. Demographics and risk factors were similar in both cohorts. No outpatient CT patients had a MACE prior to coronary CTA. (0.0%, 95% CI 0 to 0.9%) The median length of stay for ED-based evaluation was 6.6 hours (interquartile range 5.4 to 8.3 hours) while the outpatient group had a median length of stay of 7.0 hours (IQR 6.0 to 9.8 hours, n.s.).

CONCLUSIONS

In ED chest pain patients with a low risk of ACS, performing coronary CTA as an outpatient may be a safe strategy.

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.