Patrón de flujo en "4D Flow" y su vínculo con la aortopatía bicúspide / 4D Flow pattern and its role in bicuspid aortic valve aortopathy

ABSTRACT: Bicuspid aortic valve (BAV) disease is generally associated with thoracic aortic dilatation (TAD). Related factors include; genetical, morphological (valvular phenotype) and most recently, hemodynamic profiles associated with flow pattern and wall shear stress. Cardiac magnetic resonance 4D Flow (4DF) can give an integral evaluation of these later flow variables. Remarkable, different spectrums of flow and vortex direction exist in BAV that are related to the site of TAD (proximal or distal). Therefore, we present a 57 years old patient with BAV (Sievers 0) with anteroposterior leaflets distribution in which 4DF depicted an anteriorly and righthand oriented jet that correlated with the zone of grater AD; also, vortex rotation was counterclockwise, corresponding to the most frequent vortex type in BAV. In conclusion, 4DF is a powerful and ground-breaking tool that enhances our knowledge of BAV related aortopathy.

Atherosclerotic plaque burden evaluated from neck to groin: effect of gender and cardiovascular risk factors.

We explored the impact of gender and cardiovascular risk factors (RF) in the distribution and burden of coronary and extra-coronary atherosclerotic plaques among patients undergoing ECG-gated thoracoabdominal computed tomography angiography (CTA) from the supra-aortic trunks to the femoral arteries. We included a consecutive cohort of patients who underwent ECG-gated thoracoabdominal aortic CTA from the supra-aortic trunks to the pubic symphysis. We evaluated the number of coronary segments with plaques [segment-involvement score (SIS)]; and the extra-coronary atherosclerotic plaque burden, comprising the aorta and supra-aortic trunks, iliofemoral arteries, and visceral arteries (extra-coronary SS). A total of 3400 vascular segments were evaluated in 100 patients (mean age 67.0 ± 12.6 years, 66% male). Seventy-two (72%) patients had evidence of atherosclerosis in the coronary tree (coronary SIS ≥ 1), of which 32% was extensive (coronary SIS > 5). Males had a significantly higher prevalence of coronary SIS ≥ 1 [53 (80%), vs. 19 (56%), p = 0.018], and coronary SIS > 5 [24 (36%) vs. 8 (24%), p = 0.035] than females. Extra-coronary SS was similar between genders (males 10.2 ± 5.8 vs. females 9.7 ± 5.4, p = 0.70), irrespective of the location along the different vascular beds. The number of coronary RF was significantly related to the coronary SIS (p = 0.038), and hypertension and diabetes were consistently related to coronary and extra-coronary plaque burden. In the present study involving analysis of multiple vascular beds from the supra-aortic trunks to the femoral arteries, we identified significant sex-related differences in coronary plaque burden, whereas extra-coronary plaque burden was similar between genders irrespective of the vascular bed assessed.

Image Quality and Radiation Exposure Comparison of a Double High-Pitch Acquisition for Coronary Computed Tomography Angiography Versus Standard Retrospective Spiral Acquisition in Patients With Atrial Fibrillation.

OBJECTIVE: The aim of this study was to compare image quality and radiation dose of coronary computed tomography (CT) angiography performed with dual-source CT scanner using 2 different protocols in patients with atrial fibrillation. METHODS: Forty-seven patients with AF underwent 2 different acquisition protocols: double high-pitch (DHP) spiral acquisition and retrospective spiral acquisition. The image quality was ranked according to a qualitative score by 2 experts: 1, no evident motion; 2, minimal motion not influencing coronary artery luminal evaluation; and 3, motion with impaired luminal evaluation. A third expert solved any disagreement. RESULTS: A total of 732 segments were evaluated. The DHP group (24 patients, 374 segments) showed more segments classified as score 1 than the retrospective spiral acquisition group (71.3% vs 37.4%). Image quality evaluation agreement was high between observers (κ = 0.8). There was significantly lower radiation exposure for the DHP group (3.65 [1.29] vs 23.57 [10.32] mSv). CONCLUSIONS: In this original direct comparison, a DHP spiral protocol for coronary CT angiography acquisition in patients with atrial fibrillation resulted in lower radiation exposure and superior image quality compared with conventional spiral retrospective acquisition.

¿Es realmente útil la cardiorresonancia magnética de estrés para detectar isquemia y predecir eventos en pacientes con distinto perfil de riesgo cardiovascular? / Is stress cardiovascular magnetic resonance really useful to detect ischemia and predict events in patients with different cardiovascular risk profile?

Resumen: Objetivo: Evaluar la utilidad diagnóstica y pronóstica de la cardiorresonancia magnética de estrés (RMCE) en pacientes con distinto perfil de riesgo cardiovascular y la importancia del grado de hipoperfusión en la toma de decisiones clínicas. Método: Se analizaron los pacientes sometidos a RMCE con adenosina por sospecha de isquemia miocárdica. Se evaluó su precisión diagnóstica mediante los cocientes de probabilidad (CP) y su valor pronóstico mediante curvas de supervivencia y regresión de Cox. Resultados: Se estudió a 295 pacientes. El CP positivo fue 3.40 y el negativo 0.47. Se demostró una mayor utilidad de la resonancia en: pacientes sin cardiopatía isquémica conocida (CP positivo 4.85); pacientes con dolor torácico atípico (CP positivo 8.56);pacientes con riesgo cardiovascular bajo o intermedio (CP positivo 3.87), y pacientes con hipoperfusión moderada o grave (CP positivo 8.63). Se registraron 60 eventos cardiovasculares mayores. Los pacientes con resultado negativo (p = 0.001) o hipoperfusión leve (p = 0.038) presentaron una supervivencia mayor. En el análisis multivariante, un resultado moderado o grave aumentó la probabilidad de sufrir eventos (hazard ratio [HR] = 2.2; IC 95% 1.26-3.92), sin diferencias entre resultado positivo leve y negativo (HR = 0.93; IC 95% 0.38-2.28). Conclusiones: La RMCE tuvo una mayor utilidad en pacientes con riesgo cardiovascular bajo o intermedio, con dolor torácico atípico, sin cardiopatía isquémica conocida y en aquellos con hipoperfusión moderada o grave. Además, el grado de hipoperfusión fue el principal factor para guiar las decisiones clínicas.

Abstract: Objective: The aim of this study was to evaluate the diagnostic and prognostic usefulness of stress cardiovascular magnetic resonance (stress CMR) in patients with different cardiovascular risk profile and to assess if the degree of hypoperfusion is important to guide clinical decisions. Method: We included patients submitted to adenosine stress CMR to rule out myocardial ischemia. We evaluated its diagnostic accuracy with likelihood ratio (LR) and its prognostic value with survival curves and a Cox regression model. Results: 295 patients were studied. The positive LR was 3.40 and the negative one 0.47. The maximal usefulness of the test was found in patients without previous ischemic cardiomyopathy (positive LR 4.85), patients with atypical chest pain (positive LR 8.56), patients with low or intermediate cardiovascular risk (positive LR 3.87) and those with moderate or severe hypoperfusion (positive LR 8.63). Sixty cardiovascular major events were registered. The best survival prognosis was found in patients with a negative result (p = 0.001) or mild hypoperfusion (p = 0.038). In the multivariate analysis, a moderate or severe hypoperfusion increased cardiovascular event probability (HR = 2.2; IC 95% 1.26-3.92), with no differences between a mild positive and a negative result (HR = 0.93; IC 95% 0.38-2.28). Conclusions: Stress CMR was specially useful in patients with low or intermediate cardiovascular risk, patients with atypical chest pain, patients without previous ischemic cardiomyopathy and those with moderate or severe hypoperfusion. Hypoperfusion degree was the main issue factor to guide clinical decisions.

Screening for asymptomatic coronary artery disease in patients with type 2 diabetes mellitus

ABSTRACT Diabetes is a very frequent disease and it is estimated that its prevalence will continuously increase during the next two decades. The arteriosclerotic process in diabetic patients progresses earlier and more diffusely, and it is more accelerated in the diabetic patient than in the overall population. In diabetic subjects, acute myocardial infarction (AMI) and stroke are the leading causes of death, but the presence of arterial disease is not always detected before the development of the acute arterial event. Several times, AMI is asymptomatic or present nonspecific symptoms, and it is the initial form of presentation of coronary artery disease causing an important delay in initiating cardiovascular treatment in these patients. The purpose of this review article is to discuss how to screen and early diagnose the presence of coronary artery disease in asymptomatic diabetic patients, based on new available diagnostic resources. Currently, the most recommended technique used for screening coronary artery disease in these patients is myocardial perfusion scintigraphy or stress echocardiography because of greater sensitivity and specificity in relation to the exercise test. However, technological advances have enabled the development of new imaging diagnostic methods that are less invasive than conventional coronary angiography, and which gradually gain importance in the diagnosis of coronary artery disease as they show higher effectiveness with lower invasiveness and risk. Arch Endocrinol Metab. 2016;60(2):143-51.

Late gadolinium enhancement assessed by cardiac magnetic resonance imaging in heart transplant recipients with different stages of cardiac allograft vasculopathy.

AIMS: Cardiac allograft vasculopathy (CAV), which limits long-term survival after heart transplantation (HTX), is usually evaluated by coronary angiography (CA). Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) is a non-invasive technique that can detect CAV-related myocardial infarctions. We aimed to investigate the presence of LGE infarct-typical patterns in a large sample of HTX recipients and to correlate these findings with the severity of CAV assessed by CA. METHODS AND RESULTS: LGE-CMR was performed in 132 HTX patients on a 1.5-T MRI scanner (Philips, Best, the Netherlands). Infarct-typical LGE areas were identified as bright lesions with subendocardial involvement. Infarct-atypical LGE was classified as follows: (i) right ventricle (RV) insertion, (ii) intramural, (iii) epicardial, and (iv) diffuse. CA was performed for the assessment of CAV (CAV0 = no lesion, CAV1 = mild lesions, CAV2 = moderate lesions, CAV3 = severe lesions, or mild/moderate lesions with allograft dysfunction). Infarct-typical LGE patterns were detected in 29 (22%) patients distributed in all groups and they were already present in nearly every fifth CAV0 patient, increasing significantly among CAV groups (CAV0 = 19%, CAV1 = 10%, CAV2 = 36%, and CAV3 = 71%; P < 0.01). CONCLUSION: LGE-CMR was useful to identify myocardial scar possibly related to early CAV in a significant proportion of HTX recipients, otherwise classified as low-risk patients based on CA. Therefore, LGE-CMR could be helpful to intensify CAV monitoring, medical therapy, and clinical risk stratification.

Sources of error in the measurement of aortic diameter in computed tomography scans.

OBJECTIVE: This study was conducted to determine the differences in the diameter of the thoracic aorta when measured from electrocardiographic (ECG)-gated and nongated computed tomography (CT) angiography. Another aim was to define the difference in the aortic diameter when it is measured at peak systole and end diastole in ECG-gated scans. METHODS: The gated and nongated CT angiograms of 27 patients (mean age, 58 ± 16 standard deviation [SD] years) obtained on a 256-slice multidetector CT scanner were used. The transverse and anteroposterior diameters and the lumen areas were measured at 1, 4, and 8 cm below the origin of the left subclavian artery. RESULTS: There was a significant difference in the aortic measurements of diameter between gated and nongated scans found in samples taken at 1, 4, and 8 cm distal to the left subclavian artery (P < .0001). We found a considerable difference between the systolic and diastolic diameters (P < .0001). The maximum change in diameter between systole and diastole was 2.9 ± 0.9 (SD) mm (14.5%, P < .0001) at 1 cm, 5.4 mm (22.6%; median, 1.7 mm; P < .0001) at 4 cm, and 4.4 mm (16.9%; median, 1.3 mm; P < .0001) at 8 cm. There was a significant difference between the transverse and anteroposterior diameters in systole and diastole at all locations (P < .0001): The maximum change in diameter between transverse and anteroposterior diameters in systole was 5.4 ± 1.1 (SD) mm (15.7%, P < .0001) at 1 cm, 5.8 mm (19%; median, 1.4 mm; P < .0001) at 4 cm, and 5 mm (15%; median, 1.02 mm; P < .0001) at 8 cm. There was also a substantial difference between measuring the transverse diameter directly and deriving it from the lumen area (P < .0001). CONCLUSIONS: Our results showed an important difference between systolic and diastolic diameters measurements in ECG-gated scans. The standard protocol for measuring aortic diameters in gated scans of the thoracic aorta uses images at end diastole because the lack of wall motion at this time provides better resolution. This is likely to result in undersizing that, in some instances, may threaten stability and the proper seal of the stent graft. The dimensions of the aorta in a gated CT should be measured at peak systole rather than the conventional end diastole used today. Most medical centers use nongated CT or gated CT scans in end diastole to calculate sizes of endografts. In view of our findings, the latter method could result in potential complications.

Dual-source 256-MDCT for diagnosis of anomalous pulmonary venous drainage in pediatric population.

OBJECTIVE: The purpose of this study is to describe the MDCT findings of anomalous pulmonary venous drainage (APVD) in a pediatric population using a 256-MDCT dual-source scanner with a high-pitch protocol. CONCLUSION: MDCT is a fast and noninvasive technique that allows detailed and comprehensive visualization of APVD characteristics in a pediatric population. High-pitch acquisitions with scanners using a high volume of coverage permit low radiation doses and are an accurate modality for assessing these patients.

Radiation dose in cardiac CT angiography: protocols and image quality.

This paper aims to evaluate the radiation dose exposure of patients submitted to cardiac computed tomography angiography. The effective dose was obtained from the product of dose-length product values and the conversion factor established in the European Working Group for Guidelines on Quality Criteria in CT. The image noise and contrast- and signal-to-noise ratios were obtained for all images. Sixty-four- and 256-slice CT angiographies were used in 211 (68.5 %) and 97 (31.5 %) patients, respectively. The calculated mean effective dose with prospective CT angiography was 6.0±1.0 mSv and the retrospective mode was 8.4±1.2 mSv. The mean image noise values were 38.5±9.5 and 21.4 ± 5.3 for prospective and retrospective modes, respectively. It was observed that the image noise increased by 44.4 % using a prospective mode. Prospective CT angiography reduces radiation dose by ∼29 % compared with the retrospective mode, while maintaining diagnostic image quality and the ability to assess obstructions in patients.

Image quality and radiation exposure with prospectively ECG-triggered axial scanning for coronary CT angiography: the multicenter, multivendor, randomized PROTECTION-III study.

OBJECTIVES: The purpose of this study was to evaluate image quality and radiation dose using a prospectively electrocardiogram (ECG)-triggered axial scan protocol compared with standard retrospective ECG-gated helical scanning for coronary computed tomography angiography. BACKGROUND: Concerns have been raised regarding radiation exposure during coronary computed tomography angiography. Although the use of prospectively ECG-triggered axial scan protocols may effectively lower radiation dose compared with helical scanning, it is unknown whether image quality is maintained in a clinical setting. METHODS: In a prospective, multicenter, multivendor trial, 400 patients with low and stable heart rates were randomized to either an axial or a helical coronary computed tomography angiography scan protocol. The primary endpoint was to demonstrate noninferiority in image quality with the axial scan protocol, which was assessed on a 4-point scale (1 = nondiagnostic, 4 = excellent image quality). Secondary endpoints included radiation dose and the rate of downstream testing during 30-day follow-up. RESULTS: Image quality in patients scanned with the axial scan protocol (score 3.36 ± 0.59) was not inferior compared with helical scan protocols (3.37 ± 0.59) (p for noninferiority <0.004). Axial scanning was associated with a 69% reduction in radiation exposure (dose-length product [estimated effective dose] 252 ± 147 mGy · cm [3.5 ± 2.1 mSv] vs. 802 ± 419 mGy · cm [11.2 ± 5.9 mSv] for axial vs. helical scan protocols, p < 0.001). The rate of downstream testing did not differ (13.8% vs. 15.9% for axial vs. helical scan protocols, p = 0.555). CONCLUSIONS: In patients with stable and low heart rates, the prospectively ECG-triggered axial scan protocol maintained image quality but reduced radiation exposure by 69% compared with helical scanning. Axial computed tomography data acquisition should be strongly recommended in suitable patients to avoid unnecessarily high radiation exposure.

Improved segmentation of echocardiographic images using fusion of images from different cardiac cycles.

In this work, an algorithm for the detection of the left ventricular border in two-dimensional long axis echocardiographic images is presented. In its preprocessing stage, images fusion was applied to a sequence of images composed of three cardiac cycles. This method exploits the similarity of corresponding frames from different cycles and produces contrast enhancement in the left ventricular boundary. This result improves the performance of the segmentation stage which is based on watershed transformation. The obtained left ventricle border is quantitatively and qualitatively compared with contours manually segmented by a cardiologist, and with results obtained using seven different techniques from the literature.

Función ventricular en pacientes con cardiopatía isquémica: papel del Gated-PET / Evaluation of ventricular function in patients with coronary artery disease: role of Gated-PET

Positron emission tomography (PET), in its synchronized mode, also known as Gated-PET, is a powerful diagnostic tool in ischemic cardiopathy. This technique allows adding information regarding cardiovascular system functionality to traditionally PET-generated data on myocardial perfusion and endothelial function. With the aid of radiopharmaceuticals such as nitrogen-13 (13N) and 82-rubidium (82Rb), both with ultra-short half-lives, it's possible to perform a myocardial dynamic evaluation. Recently, our group has begun the first protocol ever in Latin America to include Gated-PET. From a group of 20 patients, in 14 of them (70%), it was possible to diagnose myocardial ischemia. In 13 from those patients, a significant decrease in the left ventricular ejection fraction (LVEF) during pharmacological onset with adenosine, was observed. In 6 patients (30%), myocardial ischemia was undiagnosed. After the analysis of Gated-PET data, we found that in 5 of them, LVEF was increased during pharmacological onset with adenosine. In healthy subjects, normal behavior consists of a LVEF increase in order to compensate body metabolic demands.

[Evaluation of ventricular function in patients with coronary artery disease: role of Gated-PET]. / Función ventricular en pacientes con cardiopatía isquémica: papel del Gated-PET.

Positron emission tomography (PET), in its synchronized mode, also known as Gated-PET, is a powerful diagnostic tool in ischemic cardiopathy. This technique allows adding information regarding cardiovascular system functionality to traditionally PET-generated data on myocardial perfusion and endothelial function. With the aid of radiopharmaceuticals such as nitrogen-13 (13N) and 82-rubidium (82Rb), both with ultra-short half-lives, it's possible to perform a myocardial dynamic evaluation. Recently, our group has begun the first protocol ever in Latin America to include Gated-PET. From a group of 20 patients, in 14 of them (70%), it was possible to diagnose myocardial ischemia. In 13 from those patients, a significant decrease in the left ventricular ejection fraction (LVEF) during pharmacological onset with adenosine, was observed. In 6 patients (30%), myocardial ischemia was undiagnosed. After the analysis of Gated-PET data, we found that in 5 of them, LVEF was increased during pharmacological onset with adenosine. In healthy subjects, normal behavior consists of a LVEF increase in order to compensate body metabolic demands.