Enhanced prognostic stratification of CAD patients with low ejection fraction by stress-rest Tc99m tetrofosmin gated-spect

Objective - This study was performed to assess whether post-stress and rest functional parameters, as measured by gated-SPECT, provide additional predictive value for long-term prognosis, over clinical and perfusion data in patients (pts.) with low left ventricular ejection fraction (LVEF). Methods - 647 consecutive pts. underwent stress/rest gated-SPECT, and 497 were followed for a mean period of 516 \ub1 264 days. Segmental perfusion and motion/thickening (post-stress and rest) were analysed visually, while EF and LV volumes were calculated using an automatic algorithm (QGS). The post-stress and rest ratio were determined for both end-diastolic (EDV) and end-systolic volume (ESV), while the post-stress LVEF change was calculated subtracting rest-EF from stress-EF. Results - 84/497 pts. showed rest EF < 40%, and 15/ 84 (18%) experienced a cardiac event (3 cardiac deaths, 1 infarction, 3 hospitalized angina and 9 late revascularizations). The perfusion and functional parameters were not significantly more compromised in pts. with cardiac events compared with pts. without events. Post-stress ESV was the only index significantly higher in pts. with low EF and events compared with pts. with low EF without events (150 \ub1 72 ml vs. 123 \ub1 53 ml, P = 0.02). Univariate Cox analysis of clinical, perfusion and functional data showed that the best predictor of cardiac events was stress-ESV (score 6.5, P= 0.01), followed by rest-ESV, rest-EDV, stress-EDV and stress-LVEF. Multivariate analysis demonstrated that the addition of stress-ESV to stress-EF, yielded a significant increase in the global \u3c72 in the prediction of hard events (cardiac death/infarction) (score 4.634, P = 0.03). Conclusion - In patients with depressed LVEF, stress-ESV was the only independent predictor of long-term outcome

Enhanced prognostic stratification of CAD patients with dilated left ventricle by stress and rest functional parameters and 99mTc-tetrofosmin gated-SPECT

Purpose. To evaluate whether the post-stress and rest functional parameters, measured by Gated-SPECT, have incremental prognostic value compared with perfusion parameters in predicting cardiac events (CE), in a population of CAD patients with dilated LV. Materials and methods. A total of 670 consecutive patients (mean age: 62; range 29-86 yrs.) underwent conventional diagnostic 2-day gated-SPECT with 99mTc-tetrofosmin (55% exercise stress test, 45% dip stress): 605 patients (mean age: 62 yrs., range: 34-86 yrs.) had known or suspected CAD, whereas 65 (mean age: 60 yrs, range: 29-80 yrs) had low pre-test likelihood of CAD (<10%), a normal post-stress perfusion scan and no hypertension. Fifty-three percent of CAD patients had a history of MI. Perfusion was analyzed on ungated images using 20 segments scored on a 5-point scale (0=normal, 4=no uptake), while wall thickening was assessed visually on stress/rest end-systolic images using a 4-point score (0=normal, 3=absence of WT). LVEF and volumes were calculated using an automatic algorithm. Post-stress and rest ratio were determined for both end-diastolic and end-systolic volume, while the post-stress LVEF change (d-LVEF) was calculated according to the following formula: (Stress LVEF-rest LVEF)/ rest LVEF* 100. Results. By using a cutoff value of 126 ml for rest-EDV, and of 68 ml for rest-ESV we found a LV dilation in 129/605 patients (21%). These thresholds were the mean values plus two standard deviations obtained in the control group. 111/129 (86%) were followed up for a mean period of 14 7.0 months. 83 of 111 (75%) patients had a history of MI and forty three (39%) had undergone surgical revascularizations. During the follow-up, 21 events (5 cardiac deaths, 3 nonfatal MI, 13 late revascularizations) occurred. All post-stress perfusion and functional parameters were more compromised in patients with CE compared with patients without events, but only rest EDV, rest ESV, post-stress ESV and WT-SSS reached statistical significance (201 ml vs 176 ml; p=0.035; 137 ml vs 113 ml; p=0.047; 143 ml vs 117 ml; p=0.034, 19 vs 15; p=0.048, respectively). Multivariate Cox proportional analysis demonstrated that stress ESV added significantly prognostic information over WT-SSS in predicting CE (p=0.046). Conclusions. Stress ESV has incremental prognostic value compared with wall thickening in predicting CE, in CAD patients with dilated cardiomyopathy. Perfusion parameters failed to show prognostic information in these patients

Combined assessment of left ventricular perfusion and function by gated single-photon emission computed tomography for the risk stratification of high-risk hypertensive patients

OBJECTIVE: This study was aimed at verifying whether combined information on left ventricular perfusion and function by electrocardiogram-gated single-photon emission computed tomography (SPECT) retains its known prognostic value in patients with systemic hypertension. METHODS: A total of 415 hypertensive patients underwent rest and stress (exercise in 278 and dipyridamole in 137) gated 99mTc-sestamibi SPECT and prospective follow-up for the composite endpoint of death and acute coronary syndrome. Patients undergoing revascularization were censored. The individual effect of clinical and stress imaging data on outcome was evaluated by Cox regression analysis. Model validation was performed using bootstrap methods adjusted by the degree of optimism in estimates. Survival analysis was performed using the product-limit Kaplan-Meier method. RESULTS: During a median follow-up of 24 months, 12 cardiac deaths and 32 acute coronary syndromes occurred. After adjusting for the most significant covariates, age [hazard ratio (HR) 1.62, 95% confidence interval (CI) 1.02-2.57], diabetes (HR 7.51, 95% CI 1.61-35.2), summed stress score (HR 2.06, 95% CI 1.07-4), and peak end-systolic volume (HR 3.62, 95% CI 1.35-9.69) were multivariable predictors of outcome. The normal perfusion pattern was associated with a low event rate independently of peak end-systolic volume. Conversely, in the case of moderate to severe perfusion abnormalities, a peak end-systolic volume greater than 74 ml was able to identify an increased risk of adverse outcome. Moreover, peak end-systolic volume was significantly higher among patients who died of a cardiac cause compared with those with different outcomes. CONCLUSION: A combined assessment of left ventricular perfusion and function by gated SPECT significantly improves risk stratification in hypertensive patients

Quality control on radiochemical purity in Technetium-99m radiopharmaceuticals labelling: three years of experience on 2280 procedures

Objective: the purpose of this study was to offer an example of evaluations of the ISO9001 certified internal quality assurance (QA) system of99mTc-radiopharmaceutical preparations and quality control in vivo use, using industrial kits and generators in order to identify possible sources of errors in the procedures labeling and quality control procedures. Methods: The study was performed at a single institution over a period of three years (July 1st, 2011 - July 1st, 2014), and included a total of 2280 radiopharmaceutical preparations prepared by four different technologists. All the radiopharmaceutical preparations and quality controls were performed according to each SPC provided by the manufacturer. The radiopharmaceutical preparations were the following (trade names are reported in brackets):99mTc-albumin colloid [Nanocoll] (n=349),99mTc-oxidronate [Technescan\uaehdp] (n=701),99mTc-exametazime [Ceretec] (n=169),99mTc-sestamibi [Cardiolite] (n=92),99mTc-albumin aggregated [Technescan\uaelyomaa] (n=140),99mTc-tetrofosmin [Myoview]) (n=567),99mTc-diethylene triamine pentacetic acid [Technescan\uaedtpa] (n=254), and99mTc-dimercapto succinic acid [Renocis\uae] (n=8). Data were analyzed to determine the number and type of radiopharmaceutical labelling failure and to derive the sources of these failures to define corrective actions and optimize the quality assurance program. Results: A total of 2280 procedures were performed and recorded. Following the quality control procedure six out of the 2280 preparations (0.26%) were non-conforming for clinical use with the RCP limits indicated in the SPC. Five of these were due to gross technical errors in measurements and manual procedures and were immediately repeated, returning within the limits of acceptability. The sixth failure was due to short incubation time, though compliant with the manufacturer\u2019s instructions. Conclusions: We concluded that the quality of the final product depends on a controlled production system based on the implementation of specific standard operating procedures (ISO9001, SOP) for each radiopharmaceutical production, according to strict adherence to the SPC of each radiopharmaceutical. Based on these conclusions, in our opinion every quality control suggesting a possible error in the synthesis procedure recommended in the SPC should be immediately reported to the manufacturer, for a revision of the SPC, as well as to the regulatory agencies for an alert. This strategy may in fact allow the continuous improvement of the labelling procedures and therefore the optimization of the quality control procedures frequency to ensure both patients safety and a more rational management of resources for economic sustainability