Elisa Milan

Prognostic value of tomographic rest-redistribution thallium 201 imaging in medically treated patients with coronary artery disease and left ventricular dysfunction☆☆☆

BackgroundPrevious studies show that rest-redistribution thallium imaging is useful in the assessment of myocardial viability. The impact of such studies on patient outcome is not well defined. This study examined the prognostic value of tomographic rest-redistribution 201TI imaging in 81 medically treated patients with coronary artery disease and left ventricular dysfunction.Methods and ResultsRest-redistribution single-photon emission computed tomographic images were obtained and analyzed quantitatively. The segmental thallium uptake (20 segments per patient) was interpreted as normal, reversible defect, mild to moderate fixed defect, or severe fixed defect. The thallium images were abnormal in 80 patients. The left ventricular ejection fraction was 27%±8% in patients with no redistribution and 26%±7% in patients with redistribution (difference not significant). In patients with no ischemia, there were 7±5 severe fixed defects and 5±4 mild to moderate fixed defects per patient. In patients with ischemia there were 7±4 reversible defects, 3±3 mild to moderate fixed defects, and 5±4 severe fixed defects per patient. The number of any abnormal segments was 11±5 in patients with no ischemia and 14±4 in patients with ischemia (p=0.03). During a mean follow-up of 31±24 months, there were 11 cardiac deaths in patients with no ischemia (26%) and 22 in patients with ischemia (58%); the survival rate was worse in patients with than without ischemia (p<0.05). Multivariate Cox survival analysis on important clinical, angiographic, and thallium variables showed that the presence of redistribution was an independent predictor of death (x2=5; p=0.03).ConclusionsPatients with left ventricular dysfunction and redistribution on rest thallium imaging, a marker of hibernating myocardium, have a higher mortality rate with medical therapy than do patients with a comparable degree of left ventricular dysfunction but with fixed defects only. Thus observations similar to those made with positron emission tomography can be made in a much more straightforward, simple, and probably cost-effective manner with single-photon emission computed tomography.

Feasibility and Diagnostic Accuracy of a Gated SPECT Early-Imaging Protocol: A Multicenter Study of the Myoview Imaging Optimization Group

The aim of this study was to investigate whether early (time 1, or T1) myocardial tetrofosmin imaging is feasible and as accurate in detecting coronary artery disease as is standard delayed (time 2, or T2) imaging. Methods: One hundred twenty patients (100 men and 20 women; mean age ± SD, 61 ± 10 y) with anginal symptoms underwent tetrofosmin gated SPECT. Stress/rest T1 imaging was performed at 15 min and T2 at 45 min after injection. Image quality was visually evaluated using a 4-point scale (from 0 = poor to 3 = optimal). Myocardial perfusion analysis was performed on a 20-segment model using quantitative perfusion SPECT software, and reversible ischemia was scored as a summed difference score (SDS). Coronary angiography was performed within 1 mo on all patients, and stenosis of more than 50% of the diameter was considered significant. Results: Overall, quality was scored as optimal or good for 94% of T1 images and 95% of T2 images (P = not statistically significant). Heart, lung, liver, and subdiaphragmatic counts did not differ for stress and rest T1 and T2 imaging. A good linear relationship was seen between T1 and T2 SDS (r = 0.69; P < 0.0001), and Bland–Altman analysis showed good agreement between the 2 conditions. In terms of global diagnostic accuracy, areas under the receiver-operating-characteristic curve were comparable between T1 and T2 (0.80 vs. 0.81, P = not statistically significant). Discrepancies between T1 and T2 SDS were observed in 44% of patients (T1 − T2 SDS > 2). Linear regression analysis showed a good correlation between T1 and T2 SDS (r = 0.67; P < 0.0001), whereas the Bland–Altman method showed a shift in the mean value of the difference of +2.67 ± 2.73. In patients with a T1 − T2 SDS of more than 2, areas under the receiver-operating-characteristic curves were significantly higher for T1 than for T2 images (0.79 vs. 0.70, P < 0.001). Conclusion: T1 imaging is feasible and as accurate as T2 imaging in identifying coronary artery disease. However, in a discrete subset of patients, early acquisition strengthens the clinical message of defect reversibility by permitting earlier, more accurate identification of more severe myocardial ischemia.

Cardiomyoplasty as an isolated procedure to treat refractory heart failure

OBJECTIVE Cardiomyoplasty represents a controversial therapy for chronic heart failure. The aim of this study is to review our experience of such a surgical procedure as an isolate approach to treat refractory left ventricular dysfunction. METHODS Twenty-two patients were considered candidates for cardiomyoplasty because of chronic heart failure. Mean age was 58.7 +/- 5.3 (range 48-71 years), 19 patients were male and 3 were female. Ischemic or idiopathic etiology was present in 11 cases, respectively. Traditional as well as innovative techniques were used to assess hemodynamic function. Pre-operative hemodynamic profile included mean left ventricular ejection fraction of 20 +/- 5.8% (9-28%), absence of severe right ventricular failure, and mean left ventricular end-diastolic diameter of 75.5 +/- 7.4 mm (range 61-92 m). All patients were in New York Heart Association Class III or Intermittent IV despite conventional medical therapy. RESULTS There was no intra-operative death. No additional surgery was performed. Left latissimus dorsi (LD) muscle was used in 20 cases, and right LD in two patients. Early mortality occurred in one patient (low cardiac output syndrome), whereas late mortality in five patients (three sudden deaths, one lung cancer, one heart failure). Mean follow-up is 20.7 +/- 16.7 months (3-51 months). Actuarial survival at 4 years is 70%. Cardiac index increased at 6 months (3.08 +/- 0.5 l/min per m2, P = 0.04), but no other significant changes were observed in the long term (3.03 +/- 0.7 l/min per m2, 3 +/- 0.7 l/min per m2, and 2.85 +/- 0.7 l/min per m2, at 12, 24 and 36 months, respectively). Ejection fraction improved at 6 and 12 months (29.1 +/- 1.03%, P = 0.0017; and 27.3 +/- 5.6%, P = 0.0091, respectively), while no substantial augmentation was documented at 2 and 3 years (25.6 +/- 2.5% and 25.1 +/- 4.0%, respectively). Left ventricular end-diastolic diameter was markedly reduced at 6 (73.2 +/- 8.0 mm, P = 0.0176), 12 (69.4 +/- 8.5 mm, P = 0.002) and 24 months (71.1 +/- 7.0 mm, P = 0.011), and was then stable (74.0 +/- 9.1 mm, P = 0.47) at 36 months. Postoperative pressure/volume loop evaluation showed some improvement of hemodynamic function from skeletal muscle assistance. Acute pulmonary edema episodes, as well as number of hospitalizations, were considerably reduced following cardiomyoplasty. CONCLUSIONS In our experience, cardiomyoplasty was shown to exert moderate beneficial influence on left ventricular performance, to significantly reduce cardiac dilatation and to promote the stabilization of the disease course.

Left ventricular dysfunction due to stunning and hibernation in patients

SummaryLeft ventricular dysfunction is in most cases the consequence of myocardial ischemia. It may occur transiently during an attack of angina and usually it is reversible. It may persist over hours or even days in patients after an episode of ischemia followed by reperfusion, leading to the so-called condition of stunning. In patients with persistent limitation of coronary flow, left ventricular dysfunction may be present over months and years, or indefinitely in subjects with fibrosis, scar formation, and remodeling after myocardial infarction. Bowever, chronic left ventricular dysfunction does not mean permanent or irreversible cell damage. Bypoperfused myocytes can remain viable but akinetic. This type of dysfunction has been calledhibernating myocardium. The dysfunction due to hibernation can be partially or completely restored to normal by reperfusion. It is, therefore, important to clinically recognize a hibernating myocardium. In the present article we evaluate stunning and hibernation with respect to clinical decision making and, when possible, we refer to our ongoing clinical experience.

A cost-effective sestamibi protocol in the managed health care era

BackgroundIn the managed health care era a need exists to lower the cost of diagnostic tests for coronary artery disease. One possible approach is to eliminate the rest study in the conventional stress-rest perfusion imaging protocol with single photon emission computed tomography.ObjectiveThe aim of the study was to determine the frequency with which single stress single photon emission computed tomography acquisition can be used to diagnose disease in normal patients compared with dual stress-rest protocol.Study groupTwo hundred patients without history of myocardial infarction, coronary revascularization, valvular disease, dilated cardiomyopathy, or left bundle branch block undergoing 1-day (n=86) or 2-day (n=114) stress-rest sestamibi imaging were studied. The stress was exercise in 147 patients and pharmacologic in 53 patients.ResultsOn the basis of the stress study, 112 patients had normal images, and 88 patients had abnormal images. On the basis of the combined stress-rest images, 131 patients had normal images, and 69 patients had abnormal images (agreement 85%, kappa 0.68±0.05). Only 6 (5%) of the 112 patients with normal images based on the stress images were considered to have abnormal images by the combined stress and rest images.ConclusionsIn patients with normal stress images elimination of the rest study rarely alters interpretation. Rest studies are most useful in patients with abnormal or equivocal stress images. Such selective elimination of the rest studies may decrease the cost of nuclear procedures and should be considered in the current managed care health system.

Sub-endocardial and sub-epicardial measurement of myocardial blood flow using 13NH3 PET in man

BackgroundThis study examined whether measuring myocardial blood flow (MBF) in the sub-endocardial (SEN) and sub-epicardial (SEP) layers of the left ventricular myocardium using 13NH3 positron emission tomography (PET) and an automated procedure gives reasonable results in patients with known or suspected coronary artery disease (CAD).MethodsResting and stress 13NH3 dynamic PET were performed in 70 patients. Using ≥ 70% diameter stenosis in invasive coronary angiography (ICA) to identify significant CAD, we examined the diagnostic value of SEN- and SEP-MBF, and coronary flow reserve (CFR) vs. the corresponding conventional data averaged on the whole wall thickness.ResultsICA demonstrated 36 patients with significant CAD. Their global stress average [1.61 (1.26, 1.87) mL·min−1·g−1], SEN [1.39 (1.2, 1.59) mL·min−1·g−1] and SEP [1.22 (0.96, 1.44) mL·min−1·g−1] MBF were significantly lower than in the 34 no-CAD patients: 2.05 (1.76, 2.52), 1.72 (1.53, 1.89) and 1.46 (1.23, 1.89) mL·min−1·g−1, respectively, all P < .005. In the 60 CAD vs. the 150 non-CAD territories, stress average MBF was 1.52 (1.10, 1.83) vs. 2.06 (1.69, 2.48) mL·min−1·g−1, SEN-MBF 1.33 (1.02, 1.58) vs. 1.66 (1.35, 1.93) mL·min−1·g−1, and SEP-MBF 1.07 (0.80, 1.29) vs. 1.40 (1.12, 1.69) mL·min−1·g−1, respectively, all P < .05. Using receiver operating characteristics analysis for the presence of significant CAD, the areas under the curve (AUC) were all significant (P < .0001 vs. AUC = 0.5) and similar: stress average MBF = 0.79, SEN-MBF = 0.75, and SEP-MBF = 0.73. AUC was 0.77 for the average CFR, 0.75 for SEN, and 0.70 for SEP CFR. The stress transmural perfusion gradient (TPG) AUC (0.51) was not significant. However, stress TPG was significantly lower in segments subtended by totally occluded arteries vs. those subtended by sub-total stenoses: 1.10 (0.86, 1.33) vs. 1.24 (0.98, 1.56), respectively, P < .005.ConclusionAutomatic assessment of SEN- and SEP-MBF (and CFR) using 13NH3 PET gives reasonable results that are in good agreement with the conventional average whole wall thickness data. Further studies are needed to examine the utility of layer measurements such as in patients with hibernating myocardium or microvascular disease.

The time for radionuclide ventriculography resurrection is coming

Left ventricular ejection fraction (LVEF) is the most widely used and easily available index of LV function. Almost all patients with suspected or documented heart disease undergo LVEF assessment at some point. There are nowadays, many different, invasive and non-invasive techniques for measuring LVEF including contrast ventriculography, echocardiography, magnetic resonance imaging (MR), computed tomography angiography (CT), and nuclear techniques. The nuclear techniques include the equilibrium radionuclide angiography (ERNA) referred to also as multigated angiography (MUGA), first-pass radionuclide ventriculography, gated single-photon computed tomography (SPECT) with myocardial perfusion imaging, and SPECT ERNA. Until the 1970s, the most commonly employed method of determining LV volumes and EF was LV contrast angiography performed at the time of cardiac catheterization. In 1971, Strauss et al described a new revolutionary ‘‘scintiphotographic method for measuring LVEF in man without cardiac catheterization.’’ As reported by Ashburn et al in the Seminars in Nuclear Medicine in 1973, this procedure made it possible to have multiple determinations of LVEF and volumes without additional administrations of radioactivity, allowing acquisition in different projections to evaluate wall motion of the various surfaces of the heart. Our knowledge of the physiological changes of LV function during exercise was enhanced from the application of ERNA. The introduction of computers further improved the potential widespread use of this technique, preparing the grounds for semi-automated measurement of LV function. It is of historical interest to know that these results were obtained by acquiring data on 12 K, 16 bits minicomputer system, recorded on magnetic tape and transferred them to a ‘‘large-scale digital computer as powerful as 200 k, 32 bits’’! In 1977, Borer et al demonstrated the feasibility of continuous monitoring and analysis of LV function during exercise allowing an accurate assessment of the presence and functional severity of ischemic heart disease. Global and regional dysfunction during exercise could easily be documented by ERNA. Specific features of ERNA were countbased measurement of LVEF independent from geometrical assumption and high reproducibility. Van Royen et al compared side by side echocardiographic and quantitative radionuclide LVEF: their conclusion was that LVEF determined by ERNA and echocardiography showed good agreement. Both methods provided clinically valuable measurements of LV function. However, when a precision was required for reproducible measurements, ERNA was the method of choice. Checking on PubMed with the following search terms, ‘‘radionuclide ventriculography,’’ Radionuclide angiography,’’ ‘‘ERNA,’’ ‘‘MUGA,’’ ‘‘scintigraphic angiocardiography,’’ ‘‘radionuclide cineangiography,’’ ‘‘scintiphotographic,’’ ‘‘gated scintiphotography,’’ ‘‘radio isotopic angiocardiography,’’ ‘‘radionuclide angiocardiography,’’ or ‘‘ejection fraction,’’ we found 2591 published papers on this topic. The use of ERNA reached its highest peak in the decade 1985-1995 (Figure 1), with a slow but progressive decline since. The main reason for this decline is most likely the emergence of reliable competing modalities including Reprint requests: Raffaele Giubbini MD, University of Brescia, Piazza Spedali Civili, 1, Brescia, Italy; giubbini@med.unibs.it, raffaele.giubbini@unibs.it J Nucl Cardiol 2016;23:1139–41. 1071-3581/

Assessment of myocardial viability by radionuclide imaging

34.00 Copyright 2015 American Society of Nuclear Cardiology.

Effects of left bundle branch block on myocardial FDG PET in patients without significant coronary artery stenoses.

The differentiation of viable from non viable myocardium is a key issue in the current era of revascularization. Several methods have been used to assess myocardial viability. The radionuclide detection of dysfunctional but viable myocardium depends upon the use of radiotracers whose uptake and trapping are related to presence and amount of living cells. The choice of the diagnostic technique to be applied in clinical practice depends on accuracy of the method and availability of resources. SPECT imaging with TI-201 and Tc-99m-myocardial perfusion tracers are widely available diagnostic tools. Several studies have documented their reliability to detect myocardial segments which may improve in both perfusion and function after revascularization. Positron emission tomography after injection of glucose analogues is a more sophisticated and accurate technology to detect viability, whose utilization is at present limited to few centers due to its high cost. Therefore an accurate selection of patients requiring viability studies is needed in order to identify the most appropriate diagnostic test.