Comparison of coronary flow reserve estimated by dynamic radionuclide SPECT and multi-detector x-ray CT.

BACKGROUND: Recent technical advances in multi-detector computed tomography (MDCT) allow for assessment of coronary flow reserve (CFR). We compared regional CFR by dynamic SPECT and by dynamic MDCT in patients with suspected or known coronary artery disease (CAD). METHODS: Thirty-five patients, (29 males, mean age 69 years) with greater than average Framingham risk of CAD, underwent dipyridamole vasodilator stress imaging. CFR was estimated using dynamic SPECT and dynamic MDCT imaging in the same patients. Myocardial perfusion findings were correlated with obstructive CAD (≥50% luminal narrowing) on CT coronary angiography (CA). RESULTS: Mean CFR estimated by SPECT and MDCT in 595 myocardial segments was not different (1.51 ± 0.46 vs. 1.50 ± 0.37, p = NS). Correlation of segmental CFR by SPECT and MDCT was fair (r 2 = 0.39, p < 0.001). Bland-Altman analysis revealed that MDCT in comparison to SPECT systematically underestimated CFR in higher CFR ranges. By CTCA, 12 patients had normal CA, 11 had non-obstructive, and 12 had obstructive CAD. CFR by both techniques was significantly higher in territories of normal CA than in territories subtended by non-obstructive or obstructive CAD. SPECT CFR was also significantly different in territories subtended by non-obstructive and obstructive CAD, whereas MDCT CFR was not. CONCLUSION: Despite relative underestimation of high CFR values, MDCT CFR shows promise for assessing the pathophysiological significance of anatomic CAD.

Transient left ventricular and stomach apical ballooning syndromes: when the trigger is also a clinical emergency.

A 59-year-old woman was referred to our emergency department because of epigastric pain and incoercible vomit. Electrocardiogram showed ST-segment elevation in anterior-lateral leads, but coronary angiogram revealed normal coronary tree and left ventricular angiography showed apical and midventricular akinesis with preserved basal systolic function: a diagnosis of apical ballooning syndrome was made. During the following days, the patient complained about persistent abdominal pain, and a nasogastric tube drained more than 1000 cc of dark fecaloid material. Urgent abdominal computed tomography scan showed a mural thrombus in the apex of the left ventricle and a huge diaphragmatic hernia through which more than one-half of the stomach was herniated and presented a sort of "apical stomach ballooning." Gastropexy was done; surgical diagnosis was a type IV giant diaphragmatic hernia complicated by recent gastric volvulus caused by rotation along the longitudinal cardiopyloric axis. Type IV giant diaphragmatic hernia is relatively rare, representing only about 5% to 7% of all hernias. Gastric volvulus is a severe complication, with acute mortality reported to be as high as 30% to 50%. In our case, a severe life-threatening condition as gastric volvulus triggered an apical ballooning syndrome, a transient cardiomyopathy, usually induced by emotional stressors with a long-term good prognosis. Apical ballooning syndrome must be considered an epiphenomenon of other organic diseases that may have an important role in the prognosis of the patient not only in acute but also in chronic setting. Only early determination of the true cause of apical ballooning syndrome ensures a proper treatment.

Multicentre multi-device hybrid imaging study of coronary artery disease: results from the EValuation of INtegrated Cardiac Imaging for the Detection and Characterization of Ischaemic Heart Disease (EVINCI) hybrid imaging population.

AIMS: Hybrid imaging provides a non-invasive assessment of coronary anatomy and myocardial perfusion. We sought to evaluate the added clinical value of hybrid imaging in a multi-centre multi-vendor setting. METHODS AND RESULTS: Fourteen centres enrolled 252 patients with stable angina and intermediate (20-90%) pre-test likelihood of coronary artery disease (CAD) who underwent myocardial perfusion scintigraphy (MPS), CT coronary angiography (CTCA), and quantitative coronary angiography (QCA) with fractional flow reserve (FFR). Hybrid MPS/CTCA images were obtained by 3D image fusion. Blinded core-lab analyses were performed for CTCA, MPS, QCA and hybrid datasets. Hemodynamically significant CAD was ruled-in non-invasively in the presence of a matched finding (myocardial perfusion defect co-localized with stenosed coronary artery) and ruled-out with normal findings (both CTCA and MPS normal). Overall prevalence of significant CAD on QCA (>70% stenosis or 30-70% with FFR≤0.80) was 37%. Of 1004 pathological myocardial segments on MPS, 246 (25%) were reclassified from their standard coronary distribution to another territory by hybrid imaging. In this respect, in 45/252 (18%) patients, hybrid imaging reassigned an entire perfusion defect to another coronary territory, changing the final diagnosis in 42% of the cases. Hybrid imaging allowed non-invasive CAD rule-out in 41%, and rule-in in 24% of patients, with a negative and positive predictive value of 88% and 87%, respectively. CONCLUSION: In patients at intermediate risk of CAD, hybrid imaging allows non-invasive co-localization of myocardial perfusion defects and subtending coronary arteries, impacting clinical decision-making in almost one every five subjects.

Detection of significant coronary artery disease by noninvasive anatomical and functional imaging.

BACKGROUND: The choice of imaging techniques in patients with suspected coronary artery disease (CAD) varies between countries, regions, and hospitals. This prospective, multicenter, comparative effectiveness study was designed to assess the relative accuracy of commonly used imaging techniques for identifying patients with significant CAD. METHODS AND RESULTS: A total of 475 patients with stable chest pain and intermediate likelihood of CAD underwent coronary computed tomographic angiography and stress myocardial perfusion imaging by single photon emission computed tomography or positron emission tomography, and ventricular wall motion imaging by stress echocardiography or cardiac magnetic resonance. If ≥1 test was abnormal, patients underwent invasive coronary angiography. Significant CAD was defined by invasive coronary angiography as >50% stenosis of the left main stem, >70% stenosis in a major coronary vessel, or 30% to 70% stenosis with fractional flow reserve ≤0.8. Significant CAD was present in 29% of patients. In a patient-based analysis, coronary computed tomographic angiography had the highest diagnostic accuracy, the area under the receiver operating characteristics curve being 0.91 (95% confidence interval, 0.88-0.94), sensitivity being 91%, and specificity being 92%. Myocardial perfusion imaging had good diagnostic accuracy (area under the curve, 0.74; confidence interval, 0.69-0.78), sensitivity 74%, and specificity 73%. Wall motion imaging had similar accuracy (area under the curve, 0.70; confidence interval, 0.65-0.75) but lower sensitivity (49%, P<0.001) and higher specificity (92%, P<0.001). The diagnostic accuracy of myocardial perfusion imaging and wall motion imaging were lower than that of coronary computed tomographic angiography (P<0.001). CONCLUSIONS: In a multicenter European population of patients with stable chest pain and low prevalence of CAD, coronary computed tomographic angiography is more accurate than noninvasive functional testing for detecting significant CAD defined invasively. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00979199.

Pharmacokinetic and pharmacodynamic profile of dronedarone , a new antiarrhythmic agent for the treatment of atrial fibrillation.

INTRODUCTION: Atrial fibrillation (AF) is the most common arrhythmia and is associated with increased morbidity and mortality. Dronedarone is a recent antiarrhythmic drug that has been developed for treatment of AF, with electrophysiological properties similar to amiodarone but with a lower incidence of side effects. AREAS COVERED: This review evaluates the efficacy, safety, tolerability and side effects of dronedarone in the treatment of AF. In particular, the review includes studies comparing: dronedarone and placebo (ANDROMEDA, ATHENA, DAFNE, ERATO, EURIDIS/ADONIS, HESTIA, PALLAS trials), dronedarone and amiodarone (DIONYSOS trial), ranolazine and dronedarone given alone and in combination (HARMONY trial). EXPERT OPINION: Dronedarone is an interesting antiarrhythmic agent in well-selected groups of patients. It also has several other pleiotropic effects that may potentially be beneficial in clinical practice, such as the reduction of the risk of stroke and acute coronary syndromes. In addition, combination therapies such as those with dronedarone and ranolazine, currently being investigated in the HARMONY trial, may provide another interesting approach to increase the antiarrhythmic efficacy and further reduce the incidence of side effects. A better understanding of the mechanisms underlying dronedarone's pleiotropic actions is expected to facilitate the selection of patients benefiting from dronedarone, as well as the development of novel antiarrhythmic drugs for AF.