Radiation in cardiac CT: predictors of higher dose and its reduction over time.

INTRODUCTION: Cardiac CT provides noninvasive information on cardiac anatomy, particularly in coronary artery disease. However, exposure to radiation has been identified as a limitation of this exam. The aim of this study was to evaluate variations in radiation dose over time and to identify variables associated with use of higher radiation doses. METHODS: A prospective registry of 643 patients who underwent 64-slice dual source cardiac CT scan (Dual source CT--Somaton Definition, Siemens-Medical) during 2007 and 2008 was analyzed. RESULTS: The sample was divided into quartiles according to the chronological order of the exams. There was a progressive reduction in median radiation dose in the quartiles analyzed (Q1: 8.9 [5.9-14.1], Q2: 6.6 [5.5-10.7], Q3: 6.4 [5.3-8.7], Q4: 6.1 [5.2-7.9] mSv), significant when the first quartile was compared with the others (p < 0.05). Along with this reduction, was a progressive increase in the use of a tube voltage of 100 kV (p < 0.001). Predictors of a higher radiation dose were higher body mass index, previous cardiac surgery, atrial fibrillation during acquisition, longer acquisition time and use of a tube voltage of 120 kV. When one or more of these variables were present (one third of the population), the radiation dose was significant higher (12.1 [9.5-14.8] vs. 5.7 [5.0-6.7] mSv, p < 0.001).

Hypertrophic cardiomyopathy--two atypical forms diagnosed by cardiac CT.

Hypertrophic cardiomyopathy is a relatively common genetic disease (prevalence of 0.2%), with a clinical spectrum that ranges from absence of symptoms to presentation as sudden cardiac death. Atypical forms are a diagnostic challenge and recent cardiac imaging techniques, such as cardiac CT and magnetic resonance imaging, can make an important contribution. We present a review of this disease based on two case reports.

Femoral stenosis due to a collagen closure device treated percutaneously by peripheral stenting.

Late complications from vascular closure devices, such as puncture site stenosis, are not well documented. They may be of clinical significance and probably share the same mechanism that underlies intra-coronary stent restenosis. Thus, treatment approaches based on balloon angioplasty alone may not be sufficient, and the use of stents (when possible) is safe and effective in this setting. We describe the case of a 60-year-old patient with a 90% stenosis of the femoral artery, which CT angiography strongly suggested to be secondary to previous implantation of a closure device.

Peripheral artery disease: a cause of refractory hypertension after renal transplantation.

The authors report the case of a 44-year-old man, with a history of hypertension, smoking, peripheral artery disease and chronic renal failure. After renal transplantation, the patient developed persistent high blood pressure, despite optimal medical therapy. When angiotensin-converting enzyme (ACE) inhibitor therapy was begun, he developed acute anuric renal failure, which was reversed after interruption of the ACE inhibitor. After the initial clinical evaluation, the patient was referred for renal angiography, which revealed critical stenosis of the proximal left common iliac artery, just above the renal graft artery anastomosis. The patient underwent successful angioplasty and stenting of the lesion, with complete normalization of blood pressure.

Inverted Variant of Takotsubo Syndrome Caused by Inhaled Adrenergic Beta-2 agonists.

Takotsubo syndrome (TS) is an acute and reversible clinical syndrome characterized by transient hypokinesis of the left ventricular (LV) apex. Variant forms of LV dysfunction have been reported, including inverted Takotsubo syndrome (ITS), which represents only 5% of cases and has previously been linked to excessive use of inhaled adrenergic beta-2 agonists. The authors describe the case of a 60-year-old female patient who was diagnosed with ITS after the excessive use of inhaled adrenergic beta-2 agonists. This case highlights an uncommon variant of this syndrome that may not be obvious and must be suspected in this particular context. LEARNING POINTS: Takotsubo syndrome (TS) was initially described with a classic pattern of LV apical akinesis and accounts for around 75-80% of cases. Variants including inverted Takotsubo (also known as basal variant) can affect other areas of the myocardium.Several physiopathological mechanisms have been implicated. Catecholamine-induced cardiotoxicity is one of the most supported theories, while other triggers, including excessive use of inhaled beta-2 agonists, have also been described.Treatment of TS is mainly symptomatic and conservative and frequently leads to rapid resolution and LV function recovery.

Glucose metabolism in non-diabetic patients with stable coronary artery disease.

BACKGROUND: Diabetes and other forms of impaired glucose metabolism (IGM) can be present in patients with coronary artery disease (CAD), despite normal fasting glycemia and no prior evidence of diabetes. Undiagnosed IGM can be associated with increased risk of cardiovascular events. OBJECTIVE: To assess the prevalence of IGM in patients with CAD and without diabetes and to identify its repercussions on their cardiovascular risk profile. METHODS: Consecutive patients with CAD documented by angiography, without prior history of diabetes and fasting glycemia < 126 mg/dL, were studied. An oral glucose tolerance test (OGTT) was performed to identify and classify IGM. The patients were divided into three groups: normal if fasting glycemia < 100 mg/dL and normal OGTT; prediabetes if fasting glycemia > or = 100 mg/dL and abnormal OGTT, with 2-h glycemia > or = 140 and < 200 mg/dL; and diabetes if 2-h glycemia > or = 200 mg/dL after OGTT. For assessment of the cardiovascular risk profile, various clinical, laboratorial (including lipid profile, fasting insulinemia 2 h after OGTT, insulin resistance index and A1c hemoglobin) and angiographic characteristics were analyzed. The differences between groups were determined. RESULTS: 54 patients were studied (mean age 65 +/- 9 years, 78 % male) and IGM was identified in 37 (69%), with prediabetes in 23 (43%) and diabetes in 14 (26%). Patients with IGM had more dyslipidemia, higher levels of fasting glycemia, triglycerides and urea and lower HDL cholesterol. Metabolic syndrome was diagnosed in 12% of patients in the normal group, 44% in the prediabetes group and 50% in the diabetes group (p = 0.047). CAD was more severe in the presence of IGM, being multivessel in 84% of these patients versus 59% in the normal group (p = 0.046). CONCLUSION: In patients with CAD without clinical suspicion of diabetes, a routine OGTT can identify a significant percentage with prediabetes and diabetes, which can have a negative impact on their cardiovascular risk profile.

Pre-test probability of obstructive coronary stenosis in patients undergoing coronary CT angiography: Comparative performance of the modified diamond-Forrester algorithm versus methods incorporating cardiovascular risk factors.

BACKGROUND: Current guidelines recommend the use of the Modified Diamond-Forrester (MDF) method to assess the pre-test likelihood of obstructive coronary artery disease (CAD). We aimed to compare the performance of the MDF method with two contemporary algorithms derived from multicenter trials that additionally incorporate cardiovascular risk factors: the calculator-based 'CAD Consortium 2' method, and the integer-based CONFIRM score. METHODS: We assessed 1069 consecutive patients without known CAD undergoing coronary CT angiography (CCTA) for stable chest pain. Obstructive CAD was defined as the presence of coronary stenosis ≥50% on 64-slice dual-source CT. The three methods were assessed for calibration, discrimination, net reclassification, and changes in proposed downstream testing based upon calculated pre-test likelihoods. RESULTS: The observed prevalence of obstructive CAD was 13.8% (n=147). Overestimations of the likelihood of obstructive CAD were 140.1%, 9.8%, and 18.8%, respectively, for the MDF, CAD Consortium 2 and CONFIRM methods. The CAD Consortium 2 showed greater discriminative power than the MDF method, with a C-statistic of 0.73 vs. 0.70 (p<0.001), while the CONFIRM score did not (C-statistic 0.71, p=0.492). Reclassification of pre-test likelihood using the 'CAD Consortium 2' or CONFIRM scores resulted in a net reclassification improvement of 0.19 and 0.18, respectively, which would change the diagnostic strategy in approximately half of the patients. CONCLUSIONS: Newer risk factor-encompassing models allow for a more precise estimation of pre-test probabilities of obstructive CAD than the guideline-recommended MDF method. Adoption of these scores may improve disease prediction and change the diagnostic pathway in a significant proportion of patients.

Ablation of atrial fibrillation in mitral valve disease patients: five year follow-up after percutaneous pulmonary vein isolation and mitral balloon valvuloplasty.

BACKGROUND: The association between atrial fibrillation (AF) and mitral valve disease is frequent. Isolation of the pulmonary veins by radiofrequency energy applications performed intraoperatively has been proposed for patients with AF in whom mitral valve surgery has been indicated. Balloon mitral valvuloplasty is currently the preferred procedure for patients with mitral stenosis and a favorable valve anatomy. AIM: To evaluate the short- and long-term results of percutaneous pulmonary vein isolation for the treatment of AF in patients with mitral stenosis undergoing balloon mitral valvuloplasty. METHODS: Five patients (four male and one female, age 43 +/- 4 years) underwent balloon mitral valvuloplasty concomitant with pulmonary vein isolation between August 1996 and February 1997. These patients had permanent AF, diagnosed 31 +/- 12 months previously; their mitral valve area was 1.0 +/- 0.25 cm2 and their left atria measured 54 +/- 5 mm. Balloon mitral valvuloplasty was performed via a transseptal approach, and then four ablation lines were created in the left atrial posterior wall to encircle all four pulmonary veins. Radiofrequency applications lasted 45 seconds each, and aimed at a maximum preset temperature of 65 degrees C. Electrical cardioversion was performed at the end of the procedure. RESULTS: Mitral valve area increased 1.0 +/- 0.3 cm2 after valvuloplasty. The number of radiofrequency applications per patient was 37 +/- 3, and the average duration of the entire treatment was 131 +/- 28 minutes. Fluoroscopy time averaged 32 +/- 12 minutes. All patients were discharged in sinus rhythm, and mitral flow Doppler evaluation at one month showed a biphasic pattern in all cases, with the A wave measuring 70 +/- 15 cm/sec. Three patients maintained sinus rhythm at five-year follow-up. Of these patients, one had developed a left atrial flutter at four-year follow-up and underwent ablation. The remaining two patients presented AF at five year follow-up. CONCLUSIONS: Percutaneous isolation of the pulmonary veins concomitant with balloon mitral valvuloplasty had suppressed AF in 60% of patients by five-year follow-up.

Safety evaluation of the use of femural percutaneous closure systems with simultaneous use of abciximab.

INTRODUCTION: The growing use of abciximab during coronary angioplasty, with 12 hours of intravenous perfusion, prolongs hospital stay and increases the risk of hemorrhage after sheath removal at the puncture site. Femoral percutaneous closure devices can reduce immobilization time, but their safety in the presence of abciximab in respect to hemorrhage has not been clearly determined. OBJECTIVES: To evaluate the safety and efficacy of the Perclose system in patients undergoing angioplasty with abciximab. POPULATION AND METHODS: The Perclose system was used in 79 patients undergoing angioplasty, with abciximab in 31 patients (58.6 +/- 12.2 years, 90% male, p = NS)--Group 1, and 48 pts without abciximab (61.8 +/- 10.9 years, 79% male, p = NS)--Group 2. We compared heparin dose, sheath diameters, primary success rate, coronary care unit admissions and minor and major complications. One patient was previously anticoagulated with warfarin and all the others were on oral antiplatelet therapy before and after angioplasty. RESULTS: Primary success with the use of the Perclose system was 78%. We found no significant statistical differences between groups in respect to the presence of diabetes, sheath diameter or referral for intervention. Heparin dosage was slightly higher in group 2 (p = 0.09) and ACT was also higher in group 2 (p = 0.01). More patients in group 1 had delayed ambulation (p = 0.04) due to abciximab perfusion. In 7 patients in group 1 and 9 in group 2, additional manual/mechanical compression was needed for moderate bleeding in the first hours (p = NS). One rupture of the femoral artery with need for surgical repair (primary failure) and another delayed rupture (48 hours) occurred in group 1 (both with an associated infection), and 1 pseudoaneurysm in a patient from group 2, without abciximab but taking warfarin (p = NS). None of the variables analyzed determined the occurrence of complications. Only oral anticoagulation determined the occurrence of major complications. CONCLUSIONS: User of the Perclose system for percutaneous closure of the femoral artery in patients undergoing coronary angioplasty with simultaneous use of abciximab was not associated with greater morbidity than in patients without glycoprotein IIb/IIIa receptor antagonists.

Body mass index as a predictor of the presence but not the severity of coronary artery disease evaluated by cardiac computed tomography.

BACKGROUND: The relation between body mass index (BMI) and coronary artery disease (CAD) extension remains controversial. The aim of this study was to evaluate the correlation between BMI and CAD extension documented by coronary computed tomography angiography (CCTA). METHODS AND RESULTS: Prospective registry including 1706 consecutive stable patients that performed CCTA (dual source scanner) for the evaluation of CAD. The population was stratified by BMI: normal 530 (31.1%), overweight 802 (47.0%) and obesity 374 (21.9%). BMI was significantly higher in patients with CAD (27.7 ± 4.3 vs 26.8 ± 4.3 kg/m(2), p < 0.001); these patients were also older, more often male and had higher prevalence of diabetes, hypertension and dyslipidemia. By multivariate analysis (logistic regression) BMI remains an independent predictor of CAD (odds ratio (OR) 1.03, 95% confidence interval (CI) 1.01-1.06; p = 0.012). Regarding the severity of CAD, BMI was not significantly different among patients with and without obstructive CAD (27.7 ± 4.3 vs 27.2 ± 4.3 kg/m(2), p = 0.120). In 319 patients (4516 segments; 4077 evaluable), a detailed atherosclerotic burden was evaluated and compared among BMI classes, defined according to the presence of plaque and the degree of stenosis. Obstructive CAD was identified in 16.9% of the patients and 45.1% had non-obstructive CAD. The discriminative threshold for high burden, established by the segment involvement score (SIS), was >5 segments with plaque (15.4% patients). The prevalence of SIS >5 among the BMI classes was: 18.7%, 13.7% and 13.6% for normal, overweight and obesity respectively (p values for the specific classes versus all other patients: 0.241, 0.450 and 0.663). CONCLUSIONS: In this population of stable patients undergoing CCTA for suspected CAD, BMI was an independent predictor of its presence, but was not correlated with the coronary disease severity.

Percutaneous coronary intervention of unprotected left main disease: five-year outcome of a single-center registry.

INTRODUCTION AND AIMS: Percutaneous coronary intervention (PCI) is increasingly used as a treatment option for unprotected left main coronary artery (ULMCA) lesions. We aimed to evaluate the long-term outcome of patients undergoing ULMCA PCI. METHODS AND RESULTS: We retrospectively analyzed 95 consecutive patients (median EuroSCORE I 2.9 [IQR 1.4;6.1]) who underwent ULMCA PCI between 1999 and 2006, included in a single-center prospective registry. The primary outcome was major adverse cardiovascular events (MACE) defined as all-cause death, myocardial infarction (MI) and target lesion revascularization (TLR) at five years. Forty patients (42.1%) were treated in the setting of acute coronary syndrome and 81 patients (85%) had at least one additional significant lesion (SYNTAX score 24.2±11.8). Single ULMCA PCI was performed in 33% (81.1% with drug-eluting stents) and complete functional revascularization was achieved in 79% of the patients. During the observation period, 20 patients died (21.1%), 6 (6.3%) had MI and 11 (11.6%) had TLR (total combined MACE 28.4%). Independent predictors of MACE were previous MI (HR 2.9 95% CI 1.23-6.92; p=0.015), hypertension (HR 5.7 95% CI 1.86-17.47; p=0.002) and the EuroSCORE I (HR 1.1 95% CI 1.03-1.12; p=0.001). Drug-eluting stent implantation was associated with a significantly lower MACE rate, even after propensity score adjustment (AUC=0.84; HR [corrected] 0.1; 95% CI 0.04-0.26; p<0.001). CONCLUSIONS: Unprotected left main percutaneous coronary intervention, particularly using drug-eluting stents, can be considered a valid alternative to coronary artery bypass grafting, especially in high-risk surgical patients and with favorable anatomic features.

Prevalence and predictors of coronary artery disease in patients with a calcium score of zero.

The absence of coronary calcification is associated with an excellent prognosis. However, a calcium score of zero does not exclude the presence of coronary artery disease (CAD) or the possibility of future cardiovascular events. Our aim was to study the prevalence and predictors of coronary artery disease in patients with a calcium score of zero. Prospective registry consisted of 3,012 consecutive patients that underwent cardiac CT (dual source CT). Stable patients referred for evaluation of possible CAD that had a calcium score of zero (n = 864) were selected for this analysis. The variables that were statistically significant were included in a multivariable logistic regression model. From 864 patients with a calcium score of zero, 107 (12.4%) had coronary plaques on the contrast CT (10.8%, n = 93 with nonobstructive CAD and 1.6%, n = 14 with obstructive CAD). By logistic regression analysis, the independent predictors of CAD in this population were age >55 years [odds ratio (OR) 1.63 (1.05-2.52)], hypertension [OR 1.64 (1.05-2.56)] and dyslipidemia [OR 1.54 (1.00-2.36)]. In the presence of these 3 variables, the probability of having coronary plaques was 21%. The absence of coronary artery calcification does not exclude the presence of coronary artery disease, but the prevalence of obstructive disease is very low. In this population, the independent predictors of CAD in the setting of a calcium score of zero were hypertension, dyslipidemia, and age above 55 years. In the presence of these 3 predictors, the probability of having CAD was almost 2 times higher than in the general population.

Diabetes as an independent predictor of high atherosclerotic burden assessed by coronary computed tomography angiography: the coronary artery disease equivalent revisited.

(1) To study the prevalence and severity of coronary artery disease (CAD) in diabetic patients. (2) To provide a detailed characterization of the coronary atherosclerotic burden, including the localization, degree of stenosis and plaque composition by coronary computed tomography angiography (CCTA). Single center prospective registry including a total of 581 consecutive stable patients (April 2011-March 2012) undergoing CCTA (Dual-source CT) for the evaluation of suspected CAD without previous myocardial infarction or revascularization procedures. Different coronary plaque burden indexes and plaque type and distribution patterns were compared between patients with (n = 85) and without diabetes (n = 496). The prevalence of CAD (any plaque; 74.1 vs. 56%; p = 0.002) and obstructive CAD (≥50% stenosis; 31.8 vs. 10.3%; p < 0.001) were significantly higher in diabetic patients. The remaining coronary atherosclerotic burden indexes evaluated (plaque in LM-3v-2v with prox. LAD; SIS; SSS; CT-LeSc) were also significantly higher in diabetic patients. In the per segment analysis, diabetics had a higher percentage of segments with plaque in every vessel (2.6/13.1/7.5/10.5% for diabetics vs. 1.4/7.1/3.3/4.4% for nondiabetics for LM, LAD, LCx, RCA respectively; p < 0.001 for all) and of both calcified (19.3 vs. 9.2%, p < 0.001) and noncalcified or mixed types (14.4 vs. 7.0%; p < 0.001); the ratio of proximal-to-distal relative plaque distribution (calculated as LM/proximal vs. mid/distal/branches) was lower for diabetics (0.75 vs. 1.04; p = 0.009). Diabetes was an independent predictor of CAD and was also associated with more advanced CAD, evaluated by indexes of coronary atherosclerotic burden. Diabetics had a significantly higher prevalence of plaques in every anatomical subset and for the different plaque composition. In this report, the relative geographic distribution of the plaques within each subgroup, favored a more mid-to-distal localization in the diabetic patients.