Afonso Akio Shiozaki

Dipyridamole stress and rest myocardial perfusion by 64-detector row computed tomography in patients with suspected coronary artery disease.

Recently, stress myocardial computed tomographic perfusion (CTP) was shown to detect myocardial ischemia. Our main objective was to evaluate the feasibility of dipyridamole stress CTP and compare it to single-photon emission computed tomography (SPECT) to detect significant coronary stenosis using invasive conventional coronary angiography (CCA; stenosis >70%) as the reference method. Thirty-six patients (62 +/- 8 years old, 20 men) with previous positive results with SPECT (<2 months) as the primary inclusion criterion and suspected coronary artery disease underwent a customized multidetector-row CT protocol with myocardial perfusion evaluation at rest and during stress and coronary CT angiography (CTA). Multidetector-row computed tomography was performed in a 64-slice scanner with dipyridamole stress perfusion acquisition before a second perfusion/CT angiographic acquisition at rest. Independent blinded observers performed analysis of images from CTP, CTA, and CCA. All 36 patients completed the CT protocol with no adverse events (mean radiation dose 14.7 +/- 3.0 mSv) and with interpretable scans. CTP results were positive in 27 of 36 patients (75%). From the 9 (25%) disagreements, 6 patients had normal coronary arteries and 2 had no significant stenosis (8 false-positive results with SPECT, 22%). The remaining patient had an occluded artery with collateral flow confirmed by conventional coronary angiogram. Good agreement was demonstrated between CTP and SPECT on a per-patient analysis (kappa 0.53). In 26 patients using CCA as reference, sensitivity, specificity, and positive and negative predictive values were 88.0%, 79.3%, 66.7%, and 93.3% for CTP and 68.8, 76.1%, 66.7%, and 77.8%, for SPECT, respectively (p = NS). In conclusion, dipyridamole CT myocardial perfusion at rest and during stress is feasible and results are similar to single-photon emission CT scintigraphy. The anatomical-perfusion information provided by this combined CT protocol may allow identification of false-positive results by SPECT.

Value of Real Time Three-Dimensional Echocardiography in Patients with Hypertrophic Cardiomyopathy: Comparison with Two-Dimensional Echocardiography and Magnetic Resonance Imaging

Real time three‐dimensional echocardiography (RT3DE) has been demonstrated to be an accurate technique to quantify left ventricular (LV) volumes and function in different patient populations. We sought to determine the value of RT3DE for evaluating patients with hypertrophic cardiomyopathy (HCM), in comparison with cardiac magnetic resonance imaging (MRI). Methods: We studied 20 consecutive patients with HCM who underwent two‐dimensional echocardiography (2DE), RT3DE, and MRI. Parameters analyzed by echocardiography and MRI included: wall thickness, LV volumes, ejection fraction (LVEF), mass, geometric index, and dyssynchrony index. Statistical analysis was performed by Lin agreement coefficient, Pearson linear correlation and Bland‐Altman model. Results: There was excellent agreement between 2DE and RT3DE (Rc = 0.92), 2DE and MRI (Rc = 0.85), and RT3DE and MRI (Rc = 0.90) for linear measurements. Agreement indexes for LV end‐diastolic and end‐systolic volumes were Rc = 0.91 and Rc = 0.91 between 2DE and RT3DE, Rc = 0.94 and Rc = 0.95 between RT3DE and MRI, and Rc = 0.89 and Rc = 0.88 between 2DE and MRI, respectively. Satisfactory agreement was observed between 2DE and RT3DE (Rc = 0.75), RT3DE and MRI (Rc = 0.83), and 2DE and MRI (Rc = 0.73) for determining LVEF, with a mild underestimation of LVEF by 2DE, and smaller variability between RT3DE and MRI. Regarding LV mass, excellent agreement was observed between RT3DE and MRI (Rc = 0.96), with bias of−6.3 g (limits of concordance = 42.22 to−54.73 g). Conclusion: In patients with HCM, RT3DE demonstrated superior performance than 2DE for the evaluation of myocardial hypertrophy, LV volumes, LVEF, and LV mass.

Late Gadolinium Enhancement Magnetic Resonance Imaging in the Diagnosis and Prognosis of Endomyocardial Fibrosis Patients

Background— Endocardial fibrous tissue (FT) deposition is a hallmark of endomyocardial fibrosis (EMF). Echocardiography is a first-line and the standard technique for the diagnosis of this disease. Although late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) allows FT characterization, its role in the diagnosis and prognosis of EMF has not been investigated. Methods and Results— Thirty-six patients (29 women; age, 54±12 years) with EMF diagnosis after clinical evaluation and comprehensive 2-dimensional Doppler echocardiography underwent cine-CMR for assessing ventricular volumes, ejection fraction and mass, and LGE-CMR for FT characterization and quantification. Indexed FT volume (FT/body surface area) was calculated after planimetry of the 8 to 12 slices obtained in the short-axis view at end-diastole (mL/m2). Surgical resection of FT was performed in 16 patients. In all patients, areas of LGE were confined to the endocardium, frequently as a continuous streak from the inflow tract extending to the apex, where it was usually most prominent. There was a relation between increased FT/body surface area and worse New York Heart Association functional class and with increased probability of surgery (P<0.05). The histopathologic examination of resected FT showed typical features of EMF with extensive endocardial fibrous thickening, proliferation of small vessels, and scarce inflammatory infiltrate. In multivariate analysis, the patients with FT/body surface area >19 mL/m2 had an increased mortality rate, with a relative risk of 10.8. Conclusions— Our study provides evidence that LGE-CMR is useful in the diagnosis and prognosis of EMF through quantification of the typical pattern of FT deposition.

Dipyridamole stress and rest transmural myocardial perfusion ratio evaluation by 64 detector-row computed tomography

BACKGROUND Myocardial stress CT perfusion (CTP) can detect myocardial ischemia. OBJECTIVE We evaluated the transmural perfusion ratio (TPR) of dipyridamole stress CTP to detect significant coronary stenosis (>70%) defined by quantitative invasive coronary angiography (ICA). METHODS Twenty-six patients (61.6 ± 8.0 years old; 14 males), without prior myocardial infarction, with positive single-photon emission computed tomography (SPECT; <2 months) and clinical indication for ICA, underwent a customized multidetector-row CT (MDCT) protocol with rest/stress myocardial perfusion evaluation and coronary CT angiography. TPR was defined as mean subendocardial divided by mean subepicardial attenuation and quantified on rest and stress MDCT images. Abnormal TPR was defined as 2 SDs below the mean rest TPR. RESULTS All 26 patients completed the CT protocol with no adverse events. Rest TPR was measured in all patients with a mean of 1.06 ± 0.11, and abnormal TPR was considered <0.85. For 6 patients with normal coronary arteries by ICA, the mean TPR of territories with a previous positive perfusion defect in SPECT was 1.02 ± 0.18 (95% CI, 0.86-1.18; n = 6), and mean TPR of territories without perfusion defect in SPECT was 1.03 ± 0.09 (95% CI, -0.95 to 1.11; n = 12; P = 0.83). Mean stress TPR in territories with positive SPECT and significant coronary artery disease by quantitative ICA was 0.71 ± 0.13 (95% CI, -0.64 to 0.77) and in the remote myocardial was 1.01 ± 0.09 (95% CI, -0.96 to 1.06; P < 0001). In these territories, a significant Pearsons correlation was observed (r = -0.74, P < 0.001). CONCLUSION TPR has a good correlation with SPECT and ICA to detect significant coronary stenosis.

Myocardial fibrosis in patients with hypertrophic cardiomyopathy and high risk for sudden death

FUNDAMENTO: A estratificacao de risco para morte subita na cardiomiopatia hipertrofica (CMH), continua a ser um verdadeiro desafio devido a grande heterogeneidade da sua apresentacao, em que a maioria dos individuos permanecem assintomaticos por toda sua vida e outros apresentam a morte subita como primeiro sintoma. Recentes trabalhos vem sugerindo que a fibrose miocardica pode constituir-se em um importante substrato para as arritmias ventriculares malignas, responsaveis pela morte subita nesta doenca. OBJETIVO: Avaliacao da prevalencia e quantificacao da fibrose miocardica (FM), em pacientes com CMH com alto risco ou recuperados de morte subita, portadores de cardiodesfibrilador implantavel (CDI). METODOS: Vinte e oito pacientes com CMH portadores de CDI foram submetidos a tomografia computadorizada com multiplos detectores, para realizacao da tecnica de realce tardio, e avaliacao da fibrose miocardica. RESULTADOS: 96% dos pacientes apresentavam fibrose miocardica (20,38 ± 15,55 gramas) correspondendo a 15,96 ± 10,20% da massa miocardica total. A FM foi significativamente mais prevalente que os demais fatores de risco classicos para morte subita. CONCLUSAO: Concluimos que existe uma alta prevalencia de fibrose miocardica em pacientes com cardiomiopatia hipertrofica de alto risco ou recuperados de morte subita, como neste grupo - portadores de cardiodesfibrilador implantavel. A maior prevalencia da fibrose miocardica comparada aos fatores de risco de pior prognostico levantam a hipotese de que a fibrose miocardica possa ser um importante substrato potencialmente necessario na genese das arritmias desencadeadoras da morte subita.BACKGROUND The stratification of risk for sudden death in hypertrophic cardiomyopathy (HCM) continues to be a true challenge due to the great heterogeneity of this diseases presentation, as most individuals remain asymptomatic during their entire lives and others present sudden death as first symptom. Recent studies have suggested that myocardial fibrosis may represent an important substrate for the malignant ventricular arrhythmias, that are responsible for the cases of sudden death related to this disease. OBJECTIVE To assess the prevalence and quantification of myocardial fibrosis (MF) in hypertrophic cardiomyopathy (HCM) patients with implantablecardioverter - defibrillator (ICD) indicated due to their high risk or recovered from cardiac sudden death. METHODS Twenty-eight HCM patients with ICD were submitted to multidetector computed tomography to assess myocardial fibrosis by delayed enhancement technique. RESULTS Myocardial fibrosis was present in 96% of these HCM patients with (20.38 +/- 15.55 g) comprising 15.96 +/- 10.20% of the total myocardial mass. MF was observed in a significantly higher prevalence as compared to other classical risk factors for sudden death. CONCLUSION It is possible to conclude that there is a high prevalence of myocardial fibrosis in hypertrophic cardiomyopathy patients with high-risk or recovered from cardiac sudden death, like those with clinical indication to implantable cardioverter -defibrillator. The higher prevalence of myocardial fibrosis in comparison to classical risk factors of worse prognosis raise the hypothesis that the myocardial fibrosis may be an important substrate in the genesis of lifethreatening arrhythmias in these high risk HCM population.

Cardiovascular Magnetic Resonance In Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most frequent genetic cardiac disease that causes sudden death in young people, with an incidence of 1:500 adults. The routinely used criteria for worst prognosis have limited sensitivity and specificity. Thus, the estimated risk of evolving to dilated cardiomyopathy or sudden death is somewhat inaccurate, leading to management uncertainty of HCM patients. Therefore, an accurate noninvasive method for the diagnosis of HCM with prognostic value is of great importance. In the last years, Cardiovascular Magnetic Resonance (CMR) emerged not only as a diagnostic tool, but also as a study with prognostic values, by characterizing myocardial fibrosis with great accuracy in HCM patients. Additionally, CMR identifies the types of hypertrophy, analyses the ventricular function, estimates the intraventricular gradient and allows the determination of differential diagnosis. Moreover, CMR can uniquely access myocardial fibrosis in HCM.

Myocardial Delayed Enhancement by Computed Tomography in Hypertrophic Cardiomyopathy

A 35-year-old woman with a previous diagnosis of hypertrophic cardiomyopathy (HCM) was admitted to the Heart Institute of the University of Sao Paulo Medical School for recurrent palpitation and syncope. The patient had 2 brothers who already had been diagnosed with HCM, and her mother had died suddenly at the age of 38. ECG revealed sinus-rhythm and left–bundle branch block. A tilt-table test was negative, and 24-hour Holter monitoring showed one isolated episode of nonsustained ventricular tachycardia with 3 beatings. Echocardiography revealed hypertrophy of …

Fibrose miocárdica em pacientes com cardiomiopatia hipertrófica com alto risco para morte súbita cardíaca

FUNDAMENTO: A estratificacao de risco para morte subita na cardiomiopatia hipertrofica (CMH), continua a ser um verdadeiro desafio devido a grande heterogeneidade da sua apresentacao, em que a maioria dos individuos permanecem assintomaticos por toda sua vida e outros apresentam a morte subita como primeiro sintoma. Recentes trabalhos vem sugerindo que a fibrose miocardica pode constituir-se em um importante substrato para as arritmias ventriculares malignas, responsaveis pela morte subita nesta doenca. OBJETIVO: Avaliacao da prevalencia e quantificacao da fibrose miocardica (FM), em pacientes com CMH com alto risco ou recuperados de morte subita, portadores de cardiodesfibrilador implantavel (CDI). METODOS: Vinte e oito pacientes com CMH portadores de CDI foram submetidos a tomografia computadorizada com multiplos detectores, para realizacao da tecnica de realce tardio, e avaliacao da fibrose miocardica. RESULTADOS: 96% dos pacientes apresentavam fibrose miocardica (20,38 ± 15,55 gramas) correspondendo a 15,96 ± 10,20% da massa miocardica total. A FM foi significativamente mais prevalente que os demais fatores de risco classicos para morte subita. CONCLUSAO: Concluimos que existe uma alta prevalencia de fibrose miocardica em pacientes com cardiomiopatia hipertrofica de alto risco ou recuperados de morte subita, como neste grupo - portadores de cardiodesfibrilador implantavel. A maior prevalencia da fibrose miocardica comparada aos fatores de risco de pior prognostico levantam a hipotese de que a fibrose miocardica possa ser um importante substrato potencialmente necessario na genese das arritmias desencadeadoras da morte subita.BACKGROUND The stratification of risk for sudden death in hypertrophic cardiomyopathy (HCM) continues to be a true challenge due to the great heterogeneity of this diseases presentation, as most individuals remain asymptomatic during their entire lives and others present sudden death as first symptom. Recent studies have suggested that myocardial fibrosis may represent an important substrate for the malignant ventricular arrhythmias, that are responsible for the cases of sudden death related to this disease. OBJECTIVE To assess the prevalence and quantification of myocardial fibrosis (MF) in hypertrophic cardiomyopathy (HCM) patients with implantablecardioverter - defibrillator (ICD) indicated due to their high risk or recovered from cardiac sudden death. METHODS Twenty-eight HCM patients with ICD were submitted to multidetector computed tomography to assess myocardial fibrosis by delayed enhancement technique. RESULTS Myocardial fibrosis was present in 96% of these HCM patients with (20.38 +/- 15.55 g) comprising 15.96 +/- 10.20% of the total myocardial mass. MF was observed in a significantly higher prevalence as compared to other classical risk factors for sudden death. CONCLUSION It is possible to conclude that there is a high prevalence of myocardial fibrosis in hypertrophic cardiomyopathy patients with high-risk or recovered from cardiac sudden death, like those with clinical indication to implantable cardioverter -defibrillator. The higher prevalence of myocardial fibrosis in comparison to classical risk factors of worse prognosis raise the hypothesis that the myocardial fibrosis may be an important substrate in the genesis of lifethreatening arrhythmias in these high risk HCM population.

Left ventricular free-wall rupture after acute myocardial infarction imaged by cardiovascular magnetic resonance.

This manuscript describes a rare situation where after acute myocardial infarction a patient underwent cardiovascular magnetic resonance (CMR), which identified a previously undiagnosed rupture of the free wall of the LV, leading to successful surgical management.

Treatment of patients with aortic atherosclerotic disease with paclitaxel-associated lipid nanoparticles

OBJECTIVE: The toxicity of anti-cancer chemotherapeutic agents can be reduced by associating these compounds, such as the anti-proliferative agent paclitaxel, with a cholesterol-rich nanoemulsion (LDE) that mimics the lipid composition of low-density lipoprotein (LDL). When injected into circulation, the LDE concentrates the carried drugs in neoplastic tissues and atherosclerotic lesions. In rabbits, atherosclerotic lesion size was reduced by 65% following LDE-paclitaxel treatment. The current study aimed to test the effectiveness of LDE-paclitaxel on inpatients with aortic atherosclerosis. METHODS: This study tested a 175 mg/m2 body surface area dose of LDE-paclitaxel (intravenous administration, 3/3 weeks for 6 cycles) in patients with aortic atherosclerosis who were aged between 69 and 86 yrs. A control group of 9 untreated patients with aortic atherosclerosis (72-83 yrs) was also observed. RESULTS: The LDE-paclitaxel treatment elicited no important clinical or laboratory toxicities. Images were acquired via multiple detector computer tomography angiography (64-slice scanner) before treatment and at 1-2 months after treatment. The images showed that the mean plaque volume in the aortic artery wall was reduced in 4 of the 8 patients, while in 3 patients it remained unchanged and in one patient it increased. In the control group, images were acquired twice with an interval of 6-8 months. None of the patients in this group exhibited a reduction in plaque volume; in contrast, the plaque volume increased in three patients and remained stable in four patients. During the study period, one death unrelated to the treatment occurred in the LDE-paclitaxel group and one death occurred in the control group. CONCLUSION: Treatment with LDE-paclitaxel was tolerated by patients with cardiovascular disease and showed the potential to reduce atherosclerotic lesion size.