Efficiency of tetrofosmin versus sestamibi achieved through shorter injection-to-imaging times: A systematic review of the literature.

Based on superior image quality, more accurate gated images, and lower radiation exposure to patients, Technetium-99m (Tc-99m) based tracers are preferred over Thallium-201 for SPECT myocardial perfusion imaging. The two Tc-99m tracers, sestamibi and tetrofosmin, have many similar characteristics but there are differences in blood and liver clearance rates, as well as the recommended time after injection for imaging to achieve optimal image quality. Because published peer-reviewed studies examining optimal times between injection and imaging are limited, it can be difficult to identify evidence-based opportunities to optimize imaging protocols. Using systematic literature review methods, this study was designed to identify and consolidate the available evidence on the use of sestamibi compared to tetrofosmin for variable injection to imaging times in regard to test efficiency, including test length and re-scan rates, and image quality, including overall quality and cardiac to extra-cardiac ratios. The composite of this data shows that earlier imaging with tetrofosmin is equivalent to later imaging with sestamibi when assessing subjective image quality or when quantifying heart-to-extra-cardiac ratios. Image quality and heart-to-extra-cardiac ratios comparing early versus later imaging with tetrofosmin were comparable if not equivalent to each other. The equivalency of the imaging quality occurs with 15 minutes (on average) earlier imaging compared to sestamibi and 30 minutes compared to standard time tetrofosmin. The subjective findings of equivalent image quality are also shown with objective measurements of heart-to-extra-cardiac ratios. In this review, the significantly shorter injection-to-acquisition times with tetrofosmin compared to sestamibi resulted in better efficiency and less waiting times for patients; in addition, significantly higher re-scan rates with sestamibi compared to tetrofosmin due to hepatic activity contributed to better throughput with tetrofosmin.

COOL-ARREST: Results from a Pilot Multicenter, Prospective, Single-Arm Observational Trial to Assess Intravascular Temperature Management in the Treatment of Cardiac Arrest.

Targeted temperature management (TTM) is recommended postcardiac arrest. The cooling method with the highest safety and efficacy is unknown. The COOL-ARREST pilot trial aimed to evaluate the safety and efficacy of the most contemporary ZOLL Thermogard XP Intravascular Temperature Management (IVTM) system for providing mild TTM postcardiac arrest. This multicenter, prospective, single-arm, observational pilot trial enrolled patients at eight U.S. hospitals between July 28, 2014, and July 24, 2015. Adult (≥18 years old), out-of-hospital cardiac arrest subjects of presumed cardiac etiology who achieved return of spontaneous circulation (ROSC) were considered for inclusion. Patients were excluded if (1) awake or consistently following commands after ROSC, (2) significant prearrest neurological dysfunction, (3) terminal illness or advanced directives precluding aggressive care, and (4) severe hemodynamic instability or shock. Patient temperature was maintained at 33.0°C ± 0.3°C for a total of 24 hours followed by controlled rewarming (0.1-0.2°C/h). Logistic regressions were used to assess association of good functional outcome (modified Rankin Scale ≤3) measured at the time of hospital discharge with shockable rhythm (yes/no), age, gender, race/ethnicity, lay-rescuer cardiopulmonary resuscitation, time to basic life support (minutes), time to ROSC (minutes), lactate (mg/dL), and pH on admission. The ZOLL IVTM system was effective at inducing TTM (median time to target temperature from initiation, 89 minutes [interquartile range 42-155]). Adverse events most often included electrolyte abnormalities and dysrhythmias. Of patients surviving to hospital discharge, 16/20 patients had a good functional outcome. A total of 18 patients survived through 90-day follow-up, at which time 94% (17/18) of patients had good functional outcome. The COOL-ARREST pilot trial demonstrates high safety and efficacy of the ZOLL Thermogard XP IVTM system in the application of mild TTM postcardiac arrest. This observational trial also revealed noteworthy variability in the management of postcardiac arrest patients, particularly with the use of early withdrawal of life-sustaining therapy.

Current Status of Patient Radiation Exposure of Cardiac Positron Emission Tomography and Single-Photon Emission Computed Tomographic Myocardial Perfusion Imaging.

BACKGROUND: Radiation exposure during nuclear cardiology procedures has received much attention and has prompted citations for radiation reduction. In 2010, the American Society of Nuclear Cardiology recommended reducing the average patient study radiation exposure to <9 mSv in 50% of studies by 2014. Cardiac positron emission tomography (PET) for myocardial perfusion imaging (MPI) has emerged within recent years, but current radiation exposure in cardiac nuclear PET laboratories is unknown. This study evaluated current reported patient radiation exposure from nuclear laboratories in the United States applying for Intersocietal Accreditation Commission accreditation for MPI using single photon emission computed tomography (SPECT) or PET. METHODS AND RESULTS: This was an analysis of nuclear cardiology studies submitted to the Intersocietal Accreditation Commission for either or both cardiac PET and SPECT accreditation. Cardiac SPECT data represented year 2015 while PET data combined years 2013 to 2015. Data was analyzed with χ2 and Mann-Whitney U tests (reported as median, 25th percentile, and 75th percentile). Reported PET MPI radiation exposure for 111 laboratories (532 patient cases) was 3.7 (3.2-4.1) mSv per study with no geographic variation. Reported SPECT MPI radiation exposure for 665 laboratories (3067 patient studies) was 12.8 (12.2-14.3) mSv. Highest radiation exposure was found in the South region. Technetium-only studies resulted in a median of 12.2 mSv per study. CONCLUSIONS: Radiation exposure from cardiac PET MPI in US laboratories applying for Intersocietal Accreditation Commission accreditation is low (111 laboratories, 3.7 mSv) and substantially lower than cardiac SPECT (665 laboratories, 12.8 mSv).

The Effects of In-Hospital Intravenous Cold Saline in Postcardiac Arrest Patients Treated with Targeted Temperature Management.

BACKGROUND: Recent data suggest that rapid infusion of intravenous (IV) cold saline for Targeted Temperature Management (TTM) after cardiac arrest is associated with higher rates of rearrest, pulmonary edema, and hypoxia, with no difference in neurologic outcomes or survival when administered by Emergency Medical Services. We sought to determine the effects of IV cold saline administration in the hospital setting in postcardiac arrest patients to achieve TTM and its effect on clinical parameters and neurologic outcomes. METHODS AND RESULTS: A cohort of 132 patients who completed TTM after cardiac arrest in a single institution was retrospectively studied. Patients who did not receive cold saline were matched by age, gender, Glasgow coma scale, downtime, and presenting rhythm to patients who received cold saline. Demographics, cardiac rearrest, diuretic use, time to target temperature, and Cerebral Performance Category (CPC) scores were recorded among other variables. Patients who received cold saline achieved target temperature sooner (280 vs. 345 minutes, p = 0.05), had lower lactate levels on day 1 (4.2 ± 3.5 mM vs. 6.0 ± 4.9 mM, p = 0.019) and day 2 (1.3 ± 2.2 mM vs. 2.2 ± 3.2 mM, p = 0.046), increased incidence of pulmonary edema (51.5% vs. 31.8%, p = 0.006), and increased diuretic utilization (63.6% vs. 42.4%, p = 0.014). There was no significant difference in cardiac rearrest, arterial oxygenation, and CPC scores (ps > 0.05). CONCLUSIONS: Infusion of IV cold saline is associated with shorter time to target temperature, increased incidence of pulmonary edema, and diuretic use, with no difference in cardiac rearrest, survival, and neurologic outcomes.

The Future of Cardiac Imaging: Report of a Think Tank Convened by the American College of Cardiology.

The American College of Cardiology's Executive Committee and Cardiovascular Imaging Section Leadership Council convened a discussion regarding the future of cardiac imaging among thought leaders in the field during a 2 day Think Tank. Participants were charged with thinking broadly about the future of imaging and developing a roadmap to address critical challenges. Key areas of discussion included: 1) how can cardiac imaging services thrive in our new world of value-based health care? 2) Who is the cardiac imager of the future and what is the role of the multimodality imager? 3) How can we nurture innovation and research in imaging? And 4) how can we maximize imaging information and optimize outcomes? This document describes the proceedings of this Think Tank.

Acid-base optimization during hypothermia.

Cardiac arrest (CA) often results in hemodynamic and metabolic compromise with associated poor prognosis. Therapeutic hypothermia (TH) has become the standard of care for CA survivors, decreasing reperfusion injury and intercellular acid-base disturbances, with improved neurologic outcomes. These benefits are realized despite a mild acidosis that can potentially occur during TH. By contrast, the severity of acidosis after return of spontaneous circulation (ROSC) must be monitored carefully and managed appropriately. Bicarbonate should be used only in case of severe acidosis and as a continuous infusion. The blood gas samples are usually warmed to 37 °C before analysis; hence, it is worth noting that the blood gas values are temperature dependent. Therefore, a calculated correction for values may be necessary.

Proceedings of the ASNC cardiac PET summit meeting, May 12 2014, Baltimore MD : 4. Novel applications of cardiovascular PET.

While it is well recognized that cardiac PET has the ability to accurately detect myocardial ischemia and coronary blood flow, there are multiple other novel and clinically important cardiac applications of PET which are now available for the evaluation of various disease processes of the cardiovascular system. Many of these applications utilize F18-fluorodeoxyglucose (FDG), a glucose analog which is retained within cells with a high metabolic activity and which has been used extensively in nuclear medicine to evaluate oncology patients and has recently also been used to evaluate infections. This review provides an overview of some of the clinically available novel applications, Figure 1, in cardiac PET which were discussed at the American Society of Nuclear Cardiology Cardiac PET Summit, May 12, 2014. Figure 1 Novel applications of cardiac PET.