Priyanka Singhal

Myocardial Infarction With Nonobstructed Coronary Arteries: Impact of CMR Early After Presentation

Seven to 15% of patients with acute coronary syndrome (ACS) have nonobstructed coronary arteries, an entity that is known as myocardial infarction with nonobstructed coronary arteries (MINOCA) [(1)][1]. In these patients, cardiac magnetic resonance (CMR) can identify different underlying etiologies

Improved diagnostic role of CMR in acute coronary syndromes and unobstructed coronary arteries: the importance of time-to-CMR

Background Acute coronary syndrome (ACS) still remains one of the leading causes of mortality and morbidity. In the literature 7-15% of patients with ACS have non obstructive coronary artery disease. In these patients CMR can identify different underlying etiologies, mainly myocarditis, myocardial infarction (MI) with spontaneous recanalization/embolus or Tako-Tsubo cardiomyopathy. However the diagnostic pick-up rate of these aetiologies by CMR is highly variable in the literature and patients are not consistently scanned in the same time window.

Cardiac magnetic resonance imaging (CMR) characteristics in apical versus non-apical hypertrophic cardiomyopathy (HCM)

Methods Approximately 3,100 CMR scans were reviewed from our CMR registry (Jan 2014 to Mar 2015). comprehensive CMR protocol was used including cines, early and late gadolinium enhancement imaging. 114 consecutive HCM patients were identified. A Asymmetric HCM was defined as: septal to free wall thickness ratio of > 1.3; apical HCM as apical wall thickness of > 15 mm or apical to basal LV wall thicknesses ≥ 1.3-1.5; and concentric HCM as symmetrical hypertrophy of ventricular wall without any regional preferences. Non-apical HCM group (comprising of asymmetric and concentric phenotypes) were compared with apical HCM. Fisher’s exact t-test and unpaired t-test were performed for statistical significance. P-value < 0.05 was statistically significant. Univariate and multivariate logistic regression analyses were performed to determine the CMR predictors of apical HCM. Results The final study sample consisted of 104 patients with HCM with median age 60years (IQR = 54-70) and 70% male, (10 patients excluded due to uncertain diagnosis) 70% non-apical HCM; the remainder 30% apical HCM. In the non-apical HCM group, 5 patients had concentric HCM and the rest had asymmetric HCM. The. The mean maximum LV wall thickness, mean indexed LV mass, mean indexed stroke volume, prevalence of LVOTO and SAM were significantly greater in nonapical group. Table 1 The presence of LGE was high in both groups (>85%) and was not statistically different. The univariate predictors of apical HCM included maximum LV wall thickness, indexed stroke volume, LVOT obstruction whereas in the multivariate model maximum LV wall thickness remained the only significant predictor.

Impact of cardiovascular magnetic resonance on management and clinical decision-making in patients presenting with chest pain, elevated troponin and unobstructed coronary artery

Background Management of patients presenting with chest pain, elevated troponin and unobstructed coronary artery is challenging. Cardiovascular magnetic resonance (CMR) can provide important diagnostic and prognostic information in this cohort. However, the evidence of impact of CMR on clinical management is lacking. We sought to evaluate the impact of CMR on diagnosis and clinical management in patients with chest pain, elevated troponin and unobstructed coronaries.

6 Prevalence and CMR characteristics of apical HCM

Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden cardiac death in young adults. The 3 main phenotypes are asymmetric (most common), concentric and apical. Literature suggests apical HCM is rare and more benign, but data is scarce. We sought to describe prevalence and characteristics of apical HCM in a large CMR service. Methods We reviewed 3,100 scans (Jan 2014–Mar 2015). Protocol included cines, early and late gadolinium enhancement imaging. 114 consecutive HCM patients were identified. Asymmetric HCM defined as septal/ free wall thickness ratio > 1.3; apical HCM as apical wall thickness > 15mm or apical/basal wall thicknesses ≥ 1.3–1.5. Concentric HCM defined as symmetrical hypertrophy of ventricular wall without regional preferences. Non-apical HCM (asymmetric and concentric phenotypes) were compared with apical HCM. Fisher’s exact t-test and unpaired t-test were performed for statistical significance (P-value < 0.05, statistically significant). Univariate and multivariate logistic regression analyses were performed to determine CMR predictors of apical HCM. Results 10 patients were excluded, leaving 104 patients, median age 60years; 70% male. 70% had non-apical HCM (5 patients concentric HCM, the rest asymmetric HCM) and 30% apical HCM. Mean maximum LV wall thickness, indexed LV mass, stroke volume, prevalence of LVOTO and SAM were greater in non-apical group. Presence of LGE was high in both groups (>85%) and wasn’t statistically different. Univariate predictors of apical HCM included maximum LV wall thickness, indexed stroke volume, LVOT obstruction (Table 1). In the multivariate model, maximum wall thickness remained the only significant predictor. Abstract 6 Table 1 CMR characteristics of Apical vs non-Apical HCM CMR findings: Total Cohort (n = 104) Non-apical (n = 73) Apical (n = 31) P-value Mean LVEF (%) 69.7 68.4 72.6 0.0552 Mean LVEDVI (mL/m²) 73.7 76.7 66.8 0.0718 Mean LVESVI (mL/m²) 23.8 25.5 20.1 0.1177 Mean indexed stroke volume 53.1 55.9 46.4 0.0333 Mean max. LV wall thickness (mm) 18.2 19.3 15.6 0.0001 Mean indexed LV mass 93.5 98.4 82.4 0.0102 LVOTO 35.2 41.1 12.5 0.0403 SAM 31.4 38.9 6.25 0.0143 LGE (%) 86.9 85.7 89.7 0.8063 LVEF, left ventricular ejection fraction; LVEDVI, left ventricular end diastolic volume index; LVESVI, left ventricular end systolic volume index; LVOTO, Left ventricular outflow tract obstruction; SAM, systolic anterior valve motion; LGE, late gadolinium enhancement. Conclusions Our study suggests that prevalence of apical HCM is almost 1/3rd of all observed cases. It also demonstrates that prevalence of LGE was high in apical HCM, suggesting that better prognosis of apical HCM based on the absence of myocardial fibrosis, should be reconsidered. Further large trials are needed to better understand the pathophysiology.

5 Structural predictors of atrial fibrillation in hypertrophic cardiomyopathy using cardiac magnetic resonance imaging: Abstract 5 Table 1

Background Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM) and is associated with major adverse cardiovascular events. Cardiac magnetic resonance (CMR) with its superior tissue characterisation property is currently the imaging modality of choice for HCM. Aims To identify the structural predictors of AF in HCM using CMR. Methods 114 consecutive HCM patients were identified after reviewing approximately 3,100 CMR scans from our registry (Jan 2014 to Mar 2015). Comprehensive CMR protocol was used including cines, early and late gadolinium enhancement imaging. The diagnosis of HCM was based on left ventricular (LV) maximum wall thickness ≥15 mm (or 13–14 mm in the presence of familial history and/or ECG changes), in the absence of other cardiac/systemic disorders producing a similar degree of hypertrophy. Clinical notes were evaluated to identify a documented episode of AF. Univariate and multivariate logistic regression analyses were performed to determine the CMR imaging predictors of AF in HCM. Results The final study sample consisted of 104 patients with HCM with median age 60years (IQR = 54–70) and 70% male, (10 patients excluded due to uncertain/overlapping diagnosis). 70% had non-apical HCM; the remainder 30% apical HCM. 16% (n = 17) had a documented episode of atrial fibrillation. The univariate predictors of AF included left atrial volume and the ratio of left atrial volume to LV end systolic volume whereas in the multivariate model the ratio of left atrial volume to LV end systolic volume remained the only significant predictor (p = 0.034, OR = 2.236, CI = 1.06–4.70) (Table 1). Conclusion Our study suggests that the ratio of left atrial volume to LV end systolic volume is the best predictor of AF in HCM. The simple CMR derived ratio may have potential role for AF risk stratification in HCM. Abstract 5 Table 1 Predictors of AF in HCM Sig. OR 95% C. I. Sig. OR 95% C. I. Lower Upper Lower Upper Age 0.061 1.048 0.998 1.1 0.4 1.025 0.968 1.085 LA volume 0.001 1.043 1.022 1.064 0.056 0.905 0.817 1.003 LVEF 0.318 0.976 0.93 1.024 0.068 1.025 0.998 1.052 LA/ESV 0.001 1.81 1.286 2.547 0.034 2.236 1.063 4.702 LGE 0.349 2.743 0.332 22.648 0.855 1.298 0.079 21.262 Apical HCM 0.955 1.033 0.33 3.237 0.571 0.589 0.094 3.677 Max. Thickness 0.881 1.009 0.893 1.141 0.902 1.015 0.797 1.293 LV mass 0.229 0.988 0.968 1.008 0.417 0.986 0.952 1.02 Variable(s) entered on step 1: Age, Left atrium volume, LVEF- left ventricular ejection fraction, LA/ESV- left atrial volume/left ventricular end systolic volume, LGE- late gadolinium enhancement, Apical HCM, Max. Thickness.

4 Troponin positive acute coronary syndromes and unobstructed coronary arteries: Improved diagnostic and clinical impact by performing cardiovascular magnetic resonance early after presentation

Background 7–15% of acute coronary syndrome (ACS) patients have unobstructed coronary arteries. In these patients cardiac magnetic resonance (CMR) can identify different underlying aetiologies. Aim Evaluate the diagnostic and decision making implications of CMR timing (early versus late) in patients with ACS and unobstructed coronary arteries. Methods 204 consecutive patients (mean age 55yrs, 51% males) with troponin positive ACS and unobstructed coronary arteries, referred for a CMR between September 2011 and July 2014 were evaluated. Comprehensive CMR was performed “early” (≤2weeks from presentation) in 98 patients and “late” (>2weeks from presentation) in 106. “Significant clinical impact” was predefined as change in diagnosis/management. Propensity matching was performed between early and late CMR groups to minimise selection bias. Results Overall, a cause was found in 70% of patients. CMR had significant clinical impact in 66%, including change in the final diagnosis in 54%. (Figure 1) In a multivariable model (included clinical and imaging parameters), presence of late gadolinium enhancement (LGE) and age were the only independent predictors of “significant clinical impact” (LGE OR 2.3, p = 0.02) (Table 1). In a propensity score analysis, 58 pair of patients was matched for early and late CMR. The diagnostic pick up rate in the “early” group was significantly higher than in the “late” group (88% vs 50% p < 0.0001). Myocarditis (33%) was the most common diagnosis in the “early” group, whereas myocardial infarction (22%) in the “late” group. The clinical impact also improved significantly in the early group compared to the propensity score matched late group (76% vs 51%, p = 0.01). Conclusion CMR was able to establish final diagnosis in overall 70%. CMR made significant additive clinical impact on management and diagnosis in 66%, with LGE being the best independent predictor of impact. Moreover, the diagnostic value as well as the clinical impact of CMR was highest when performed early. Abstract 4 Figure 1 Showing the change in diagnosis following CMR Abstract 4 Table 1 Predictors of clinical impact – univariate and multivariate logistic regression analysis Univariate analysis Multivariate analysis Variables Sig. OR 95% CI Sig. OR 95% CI Lower Upper Lower Upper Age 0.008 1.024 1.006 1.041 0.002 1.035 1.013 1.058 Sex 0.77 1.091 0.609 1.954 0.604 0.831 0.413 1.673 Troponin 0.209 1 1 1.001 0.474 1 1 1.001 STEMI 0.224 1.63 0.742 3.577 0.966 0.981 0.412 2.338 iEDV 0.291 1.006 0.995 1.017 0.316 1.006 0.994 1.019 LVEF 0.597 0.995 0.975 1.015 0.847 1.002 0.98 1.025 RWMA 0.121 1.616 0.881 2.966 0.959 1.02 0.475 2.192 Oedema 0.078 1.765 0.938 3.323 0.527 1.298 0.579 2.912 LGE 0.004 2.393 1.318 4.345 0.017 2.411 1.17 4.968

127 Early Versus Late CMR in Troponin-Positive Chest Pain with Unobstructed Coronaries

Background Acute coronary syndrome (ACS) is one of the leading causes of morbidity and mortality. Up to 15% of ACS patients are left with a diagnostic dilemma when no significant coronary obstruction is identified. In these patients, CMR can identify different underlying diagnoses including: myocarditis, myocardial infarction (MI) with spontaneous recanalisation/embolus or Tako-Tsubo cardiomyopathy. However, there are discrepancies in the literature on the diagnostic pick-up rate by CMR and patients are not consistently scanned in the same time window. Aim To evaluate the diagnostic role of performing CMR “early” (< 2 weeks from presentation) versus “late” (>2 weeks from presentation) in patients with troponin positive ACS and unobstructed coronaries. Methods In this retrospective observational study, performed at a large cardiothoracic tertiary centre in the South-West of England, data were collected on consecutive patients with troponin positive ACS and unobstructed coronaries, referred for a CMR (September 2011 to July 2014). CMR was performed on a 1.5T scanner (Avanto, Siemens) using a comprehensive protocol that included long- and short-axis cines, T2 weighted STIR and early and late gadolinium enhancement. Each scan was reported by a consultant with >10 yrs CMR experience. Results 204 consecutive patients (mean age 55 yrs) were included in the analysis (51% males). The median time interval between presentation and CMR was 20 days (range 1–150 days). An “early” CMR was performed in 96 patients (median 6 days and range 1–14 days) and 108 patients underwent a “late” CMR scan (median 41 days and range 15–150 days). Overall, CMR identified a diagnosis in 70% of patients, whilst the remaining 30% of patients were classified as normal/unknown diagnosis. An “early” CMR scan significantly improved the diagnostic pick-up rate compared to a “late” CMR scan: 82% vs 54% respectively (p < 0.0001). Myocarditis was the most common diagnosis in “early” CMR (34%) whereas reperfused MI in “late” CMR (26%). Conclusion The diagnostic role of CMR is significantly improved when performed within 2 weeks of acute presentation of troponin positive ACS with unobstructed coronaries. “Early” CMR established a final diagnosis in 82% of a large cohort of patients. In patients with ACS and unobstructed coronary arteries, CMR should be offered within a specified time window, ideally <2 weeks from presentation, in order to increase its diagnostic role and guide appropriate patient management. Abstract 127 Figure 1 Graph to show comparison of diagnosis made in early CMR versus late CMR Abstract 127 Table 1 Demographics table Characteristics Total cohort Early CMR Late CMR P-value Mean age (SD) 55 (17) 55 (17) 57 (17) NS Male sex% 51 54 48 NS Family history of IHD% 6 4 8 NS Diabetes% 12 8.8 16 NS History of smoking% 11 7 16 NS Mean troponin-T ng/L 640 771 496 0.0195 Median interval between acute presentation and CMR in days 20 4 49 <0.0001