Optimal 99mTc activity ratio in the single-day stress-rest myocardial perfusion imaging protocol: A multi-SPECT phantom study.

BACKGROUND: This investigation used image data generated by an anthropomorphic phantom to determine the minimal 99mTc rest-stress activity concentration ratio (R) able to minimize the ghosting effect in the single-day stress-first myocardial perfusion imaging, using different positions of the perfusion defect (PD), scanners and reconstruction protocols. METHODS: A cardiac phantom with a simulated PD was imaged under different R using different gamma cameras and reconstruction algorithms. The residual activity from precedent stress administration was simulated by modeling effective half-times in each compartment of the phantom and assuming a delay of 3 hours between the stress and rest studies. The net contrast (NC) of the PD in the rest study was assessed for different R, PD positions and scanner/software combinations. The optimal R will be the one that minimize the NC in the rest images RESULTS: The activity concentration ratio R, the position of the PD and the scanner/software combinations were all main effects with a statistically significant impact on the NC, in decreasing order of relevance. The NC diminished significantly only for R values up to 2. No further improvement was observed for NC for R values above 2 and up to 3. NC was significantly higher in anteroseptal than in posterolateral positions of the PD and higher for solid-state cameras. CONCLUSIONS: A rest-stress activity concentration ratio R of 2 in single-day stress-first myocardial perfusion imaging is enough to achieve the maximum net contrast in the PD. This ratio should be used to optimize patient's radiation exposure.

Incremental prognostic value of myocardial neuroadrenergic damage in patients with chronic congestive heart failure: An iodine-123 meta-iodobenzylguanidine scintigraphy study.

BACKGROUND: ICD in primary prevention reduced mortality in patients with heart failure (HF); however, in about 80% of the ICD recipients an event requiring a device intervention will never occur. Thus, a reliable screening test included in a multiparametric approach to appropriately select patients to ICD implantation is increasingly required. Aim of the work was to assess if the Iodine-123 Meta-Iodobenzylguanidine scintigraphy (123I-mIBG) could be useful to identify patients with HF who would not benefit from the ICD implantation because at low risk of arrhythmias. METHODS AND RESULTS: This is a retrospective multicentre study on patients undergoing 123I-mIBG from February 2012 to December 2015. Inclusion criteria where: age ≥ 18 years old, LVEF ≤ 35% with idiopathic or ischemic heart disease, no previous malignant ventricular arrhythmias. Patients were divided in two groups based on of late H/M < or ≥ 1.60 on 123I-mIBG. Primary end-point was occurrence of malignant arrhythmias. Secondary end-point was occurrence of cardiac death and hospitalization for worsening HF. MACE were mortality and malignant arrhythmias. Eighty-one patients were enrolled (mean age: 69 years). On 123I-mIBG, 54 patients had late H/M < 1.6 and 27 patients had late H/M ≥ 1.60. After a mean follow-up of 13.3 (± 9.7) months, the primary end-point occurred in 13 patients out of 81. No arrhythmias occurred in patients with H/M late ≥ 1.6. Nineteen patients out of 20 with MACE showed an H/M late < 1.6. Death in group with H/M ≥ 1.6 occurred for worsening HF. A late H/M ≥ 1.60 showed a very high NPV for arrhythmia (100%) and for death (96.3%). CONCLUSION: 123I-mIBG imaging has the capability to identify patients at low risk of events.

A retrospective multicenter study on long-term prevalence of chronic pain after cardiac surgery.

BACKGROUND: There are limited data on sternotomy as a cause of chronic postsurgical pain, mainly restricted to 1 year after surgery. AIMS: To assess the prevalence of chronic post-sternotomy pain and its interference on daily living. METHODS: In three groups of patients, a standardized telephone interview was obtained at 3 months (n = 313), 1 year (n = 313), and 3 years (n = 319) following the rehabilitation program after cardiac surgery, in 11 rehabilitation centers. Presence, site, and the severity and interference of pain on selected daily living items were assessed. RESULTS: The prevalence of pain after cardiac surgery was 35.3% in the 3-month group, 26.8% in the 1-year group, and 19.8% in the 3-year group (P < 0.0001). Pain in the 3-year group was rated as moderate to severe in one-third of the patients. In patients aged above 75 years, the prevalence of pain in the 3-month and the 3-year group was nonsignificantly different [34.2 and 29.3%, respectively (NS)]. In the 3-month group, pain was more frequent in the female (51.4%) than in the male patients (31.3%; P < 0.01); in the remaining groups, a comparable prevalence was documented. CONCLUSION: Results form this large, retrospective, multicenter survey indicated that one out of five patients still complain pain at 3 years after cardiac surgery; persistence of pain was more common in the older patients. The approach to management of chronic pain by cardiologists and cardiac surgeons should be improved.