Adele Ferro

Impact of inducible ischemia by stress SPECT in cardiac risk assessment in diabetic patients: Rationale and design of a prospective, multicenter trial

BackgroundA prospective, multiconter trial has been designed to evaluate the impact of inducible ischemia by stress single photon emission computed tomography (SPECT) in diabetic patients and to define the role of SPECT in assessing the cardiac risk in such patients. This report presents the details and implications of the Impact of Inducible Ischemia by Stress SPECT (IDIS) trial design.Methods and ResultsBetween January 2002 and September 2005, 1006 consecutive patients (649 men and 357 women; mean age, 63±9 years) with at least a 5-year history of type 2 diabetes mellitus were enrolled. All patients underwent stress-rest sestamibi SPECT imaging with physical exercise (n=573) or dipyridamole (n=433). SPECT studies will be analyzed by use of a 17-segment scoring system to calculate left ventricular ejection fraction, summed stress score, summed rest score, and summed difference score. The SPECT study will be considered abnormal if the summed stress score is 3 or greater. Patients with abnormal studies will be considered to have ischemia if the summed difference score is 2 or greater.ConclusionThe results of this trial should help to define the role of SPECT in assesing cardiac risk in diabetic patients. Furthermore, this trial will prospectively evaluate subsequent patient outcome during long-term follow-up.

PET/CT Imaging in Mouse Models of Myocardial Ischemia

Different species have been used to reproduce myocardial infarction models but in the last years mice became the animals of choice for the analysis of several diseases, due to their short life cycle and the possibility of genetic manipulation. Many techniques are currently used for cardiovascular imaging in mice, including X-ray computed tomography (CT), high-resolution ultrasound, magnetic resonance imaging, and nuclear medicine procedures. Cardiac positron emission tomography (PET) allows to examine noninvasively, on a molecular level and with high sensitivity, regional changes in myocardial perfusion, metabolism, apoptosis, inflammation, and gene expression or to measure changes in anatomical and functional parameters in heart diseases. Currently hybrid PET/CT scanners for small laboratory animals are available, where CT adds high-resolution anatomical information. This paper reviews mouse models of myocardial infarction and discusses the applications of dedicated PET/CT systems technology, including animal preparation, anesthesia, radiotracers, and images postprocessing.

Noninvasive assessment of coronary anatomy and myocardial perfusion: going toward an integrated imaging approach.

Many noninvasive imaging techniques are available for the evaluation of patients with known or suspected chronic coronary artery disease. Among these, computed tomography-based techniques allow the quantification of coronary atherosclerotic calcium and noninvasive imaging of coronary arteries, whereas nuclear cardiology is the most widely used noninvasive approach for the assessment of myocardial perfusion. The available single-photon emission computed tomography flow agents are characterized by a cardiac uptake proportional to myocardial blood flow. In addition, different positron emission tomography tracers may be used for the quantitative measurement of myocardial blood flow and coronary flow reserve. Extensive research is currently being performed in the development of noninvasive coronary angiography and myocardial perfusion imaging using cardiac magnetic resonance. Finally, new multimodality imaging systems have been recently developed, bringing together anatomical and functional information. This review sought to provide a description of the relative merits of noninvasive imaging techniques in the assessment of coronary anatomy and myocardial perfusion in patients with known or suspected coronary artery disease.

Combined effect of the force-frequency and length-tension mechanisms on left ventricular function in patients with dilated cardiomyopathy.

The myocardial length–tension and the force–frequency relations are important mechanisms that regulate the contractile strength of the heart.

Early and late effects of coronary artery bypass grafting on cardiac haemodynamics during daily physical activities in patients with coronary artery disease

This study investigated the early and late effects of coronary artery bypass grafting (CABG) on left ventricular (LV) function during different physical daily activities in patients with multivessel coronary artery disease (CAD). In ten patients with multivessel CAD, cardiac haemodynamics were assessed during a 6-min walk test and during stair climbing 8±2 days before (study 1) and 15±3 days (study 2) and 120±3 days (study 3) after CABG. LV function was monitored by an ambulatory radionuclide system. In study 1, the walk test induced a significant increase in relative end-diastolic volume (EDV) and end-systolic volume (ESV) and no change in LV ejection fraction as compared to rest. In both study 2 and study 3, EDV increased significantly and ESV was unchanged. As a consequence, LV ejection fraction rose from 48%±8% to 52%±10% and from 48%±7% to 51%±6%, respectively (both P<0.05). In study 1, stair climbing induced a significant increase in EDV and ESV and as a consequence LV ejection fraction decreased from 46%±8% to 42%±9% (P<0.05) as compared to rest. In both study 2 and study 3, EDV increased significantly whereas ESV did not change. As a consequence, LV ejection fraction rose from 48%±8% to 52%±7% and from 48%±8% to 51%±7%, respectively (both P<0.05). In conclusion, CABG has beneficial effects on cardiac performance during moderate or more intense physical activity in patients with multivessel CAD and these effects are due to improvement in systolic function. Radionuclide monitoring of LV function provides an objective method for quantitative evaluation of cardiac performance after CABG.

Post-stress left ventricular ejection fraction drop in patients with diabetes: a gated myocardial perfusion imaging study

BackgroundTo evaluate the relevance of stress-induced decrease in left ventricular ejection fraction (LVEF) in patients with type-2 diabetes.MethodsA total of 684 diabetic patients with available rest and post-stress gated myocardial perfusion single-photon emission computed tomography (MPS) data were enrolled. An automated algorithm was used to determine the perfusion scores using a 17-segment model. LVEF drop was considered significant if the post-stress LVEF was ≥5% below the rest value. Follow-up data were available in 587 patients that were followed for the occurrence of cardiac death, nonfatal myocardial infarction, or unstable angina requiring revascularization.ResultsA post-stress LVEF drop ≥5% was observed in 167 (24%) patients. Patients with LVEF drop had higher summed stress score (p < 0.05), summed difference score (p < 0.001), and rest LVEF (p < 0.001) compared to patients without. Conversely, summed rest score, a measure of infarct size, was comparable between the two groups. At multivariable analysis, summed difference score and rest LVEF were independent predictors (both p < 0.001) of post-stress LVEF drop. Myocardial perfusion was abnormal in 106 (63%) patients with post-stress LVEF drop and in 296 (57%) of those without (p = 0.16). The overall event-free survival was lower in patients with post-stress LVEF drop than in those without (log rank χ2 7.7, p < 0.005). After adjusting for clinical data and MPS variables, the hazard ratio for cardiac events for post-stress LVEF drop was 1.52 (p < 0.01).ConclusionsIn diabetic patients stress-induced ischemia is an independent predictor of post-stress LVEF drop; however, a reduction in LVEF is detectable also in patients with normal perfusion. Finally, post-stress LVEF drop increases the risk of subsequent cardiac events in diabetic patients.

Haemodynamic effects of dual-chamber pacing versus ventricular pacing during a walk test in patients with depressed or normal left ventricular function.

PurposeDual-chamber rate-modulated pacing provides haemodynamic benefits compared with ventricular pacing at rest, but it is unclear whether this also holds true during physical exercise in patients with heart failure. This study assessed the haemodynamic response to a walk test during dual-chamber pacing and ventricular pacing in patients with depressed or normal left ventricular (LV) function.MethodsTwelve patients with an LV ejection fraction <50% and 11 patients with an LV ejection fraction ≥50% underwent two randomised 6-min walk tests under dual-chamber rate-modulated pacing and ventricular pacing at a fixed rate of 70 beats/min. All patients had a dual-chamber pacemaker implanted for complete heart block. LV function was monitored by a radionuclide ambulatory system.ResultsIn patients with depressed LV function, the change from dual-chamber pacing to ventricular pacing induced a decrease in end-systolic volume at the peak of the walk test (P<0.05), with no difference in end-diastolic volume. As a consequence, higher increases in LV ejection fraction (P<0.0001) and stroke volume (P<0.01) were observed during ventricular pacing. No difference in cardiac output was found between the two pacing modes. In patients with normal LV function, the change from dual-chamber pacing to ventricular pacing induced a significant decrease in cardiac output (P<0.005 at rest and P<0.05 at the peak of the walk test).ConclusionCompared with dual-chamber rate-modulated pacing, ventricular pacing improves cardiac function and does not affect cardiac output during physical activity in patients with depressed LV function, whereas it impairs cardiac output in those with normal function.

Statin therapy modulates thickness and inflammatory profile of human epicardial adipose tissue

BACKGROUND Epicardial adipose tissue (EAT) thickness and pro-inflammatory status has been shown to be associated with several cardiac diseases, including aortic stenosis (AS). Thus, cardiac visceral fat could represent a potential new target for drugs. In the present study we evaluate the effect of statin therapy on EAT accumulation and inflammation. METHODS Echocardiographic EAT thickness was assessed in 193 AS patients taking (n.87) and not taking (n.106) statins, undergoing cardiac surgery. To explore the association between statin therapy and EAT inflammation, EAT biopsies were obtained for cytokines immunoassay determination in EAT secretomes. An in vitro study was also conducted and the modulation of EAT and subcutaneous adipose tissue (SCAT) secretomes by atorvastatin was assessed in paired biopsies. RESULTS Statin therapy was significantly associated with lower EAT thickness (p < 0.0001) and with lower levels of EAT-secreted inflammatory mediators (p < 0.0001). Of note, there was a significant correlation between EAT thickness and its pro-inflammatory status. In vitro, atorvastatin showed a direct anti-inflammatory effect on EAT which was significantly higher compared to the SCAT response to statin incubation (p < 0.0001). CONCLUSIONS The present study indicates a robust association between statin therapy and reduced EAT accumulation in patients with AS. The present data also suggest a direct relationship between EAT thickness and its inflammatory status, both modulated by statin therapy. The in vitro results support the hypothesis of a direct action of statins on EAT secretory profile. Overall our data suggest EAT as a potential new therapeutic target for statin therapy.

Ear arterial pulse computation reliability of diastolic perfusion time during stress test

Diastolic perfusion time is a critical determinant of myocardial oxygen supply when coronary artery flow is limited by a significant stenosis of the coronary vessel. Diastolic time adjustment of the ST segment depression occurring during effort enhances stress test prediction of the coronary impairment severity. Effective diastolic adjustment of ST segment requires a stable and simple to perform measurement of the diastolic perfusion time during stress test execution. The authors investigated the reproducibility of the diastolic measurements obtained using the arterial pulse of the lobulus auriculae compared to the classical phonocardiographic data. The results obtained indicate that ear arterial pulse measurement of the diastolic time is reliable avoiding the difficulties rising from using the phonocardiographic method.