Retrospective fractional dose reduction in Tc-99m cardiac perfusion SPECT/CT patients: A human and model observer study.

BACKGROUND: In the ongoing efforts to reduce cardiac perfusion dose (injected radioactivity) for conventional SPECT/CT systems, we performed a human observer study to confirm our clinical model observer findings that iterative reconstruction employing OSEM (ordered-subset expectation-maximization) at 25% of the full dose (quarter-dose) has a similar performance for detection of hybrid cardiac perfusion defects as FBP at full dose. METHODS: One hundred and sixty-six patients, who underwent routine rest-stress Tc-99m sestamibi cardiac perfusion SPECT/CT imaging and clinically read as normally perfused, were included in the study. Ground truth was established by the normal read and the insertion of hybrid defects. In addition to the reconstruction of the 25% of full-dose data using OSEM with attenuation (AC), scatter (SC), and spatial resolution correction (RC), FBP and OSEM (with AC, SC, and RC) both at full dose (100%) were done. Both human observer and clinical model observer confidence scores were obtained to generate receiver operating characteristics (ROC) curves in a task-based image quality assessment. RESULTS: Average human observer AUC (area under the ROC curve) values of 0.725, 0.876, and 0.890 were obtained for FBP at full dose, OSEM at 25% of full dose, and OSEM at full dose, respectively. Both OSEM strategies were significantly better than FBP with P values of 0.003 and 0.01 respectively, while no significant difference was recorded between OSEM methods (P = 0.48). The clinical model observer results were 0.791, 0.822, and 0.879, respectively, for the same patient cases and processing strategies used in the human observer study. CONCLUSIONS: Cardiac perfusion SPECT/CT using OSEM reconstruction at 25% of full dose has AUCs larger than FBP and closer to those of full-dose OSEM when read by human observers, potentially replacing the higher dose studies during clinical reading.

Variant Angina and Aborted Sudden Cardiac Death.

PURPOSE OF REVIEW: Variant angina, which is characterized by recurrent chest pain and transient ECG changes along with angiographic evidence of coronary artery spasm, generally has a favorable prognosis. However, episodes of ischemia caused by vasospasm may lead to potentially life-threatening ventricular arrhythmias and cardiac arrest, even in patients with no history of prior cardiac disease. This review describes the epidemiology, pathogenesis, clinical spectrum, and management of variant angina, as well as outcomes in patients who present with aborted sudden cardiac death (ASCD). RECENT FINDINGS: Contrary to prior opinions, evidence from recent observational studies indicate that patients with variant angina presenting with ASCD face a worse prognosis than those without this type of presentation. Predictors of ASCD include age, hypertension, hyperlipidemia, family history of sudden cardiac death, multi-vessel spasm, and left anterior descending artery spasm. Medical therapy alone with calcium channel blockers and nitrates may not be sufficiently protective in these patients and there is lack of concrete data on the optimal management strategy. Current guidelines recommend implantable cardiac defibrillator (ICD) therapy in patients who are survivors of cardiac arrest caused by ventricular fibrillation or unstable ventricular tachycardia after reversible causes are excluded, and should strongly be considered in these patients. Although medical therapy is absolutely imperative for patients with variant angina and a history of ASCD, ICD therapy in these patients is justified. Further large-scale studies are required to determine whether ICD therapy can improve survival in this high-risk group of patients.

MI-PACE Home-Based Cardiac Telerehabilitation Program for Heart Attack Survivors: Usability Study.

BACKGROUND: Cardiac rehabilitation programs, consisting of exercise training and disease management interventions, reduce morbidity and mortality after acute myocardial infarction. OBJECTIVE: In this pilot study, we aimed to developed and assess the feasibility of delivering a health watch-informed 12-week cardiac telerehabilitation program to acute myocardial infarction survivors who declined to participate in center-based cardiac rehabilitation. METHODS: We enrolled patients hospitalized after acute myocardial infarction at an academic medical center who were eligible for but declined to participate in center-based cardiac rehabilitation. Each participant underwent a baseline exercise stress test. Participants received a health watch, which monitored heart rate and physical activity, and a tablet computer with an app that displayed progress toward accomplishing weekly walking and exercise goals. Results were transmitted to a cardiac rehabilitation nurse via a secure connection. For 12 weeks, participants exercised at home and also participated in weekly phone counseling sessions with the nurse, who provided personalized cardiac rehabilitation solutions and standard cardiac rehabilitation education. We assessed usability of the system, adherence to weekly exercise and walking goals, counseling session attendance, and disease-specific quality of life. RESULTS: Of 18 participants (age: mean 59 years, SD 7) who completed the 12-week telerehabilitation program, 6 (33%) were women, and 6 (33%) had ST-elevation myocardial infarction. Participants wore the health watch for a median of 12.7 hours (IQR 11.1, 13.8) per day and completed a median of 86% of exercise goals. Participants, on average, walked 121 minutes per week (SD 175) and spent 189 minutes per week (SD 210) in their target exercise heart rate zone. Overall, participants found the system to be highly usable (System Usability Scale score: median 83, IQR 65, 100). CONCLUSIONS: This pilot study established the feasibility of delivering cardiac telerehabilitation at home to acute myocardial infarction survivors via a health watch-based program and telephone counseling sessions. Usability and adherence to health watch use, exercise recommendations, and counseling sessions were high. Further studies are warranted to compare patient outcomes and health care resource utilization between center-based rehabilitation and telerehabilitation.

Performance on the Cardiovascular In-Training Examination in Relation to the ABIM Cardiovascular Disease Certification Examination.

The American College of Cardiology In-Training Exam (ACC-ITE) is incorporated into most U.S. training programs, but its relationship to performance on the American Board of Internal Medicine Cardiovascular Disease (ABIM CVD) Certification Examination is unknown. ACC-ITE scores from third-year fellows from 2011 to 2014 (n = 1,918) were examined. Covariates for regression analyses included sex, age, medical school country, U.S. Medical Licensing Examination Step, and ABIM Internal Medicine Certification Examination scores. A secondary analysis examined fellows (n = 511) who took the ACC-ITE in the first and third years. ACC-ITE scores were the strongest predictor of ABIM CVD scores (p < 0.0001), and the most significant predictor of passing (p < 0.0001). The change in ACC-ITE scores from first to third year was a strong predictor of the ABIM CVD score (p < 0.001). The ACC-ITE is strongly associated with performance on the ABIM CVD Certification Examination.

Changing trends in the long-term prognosis of patients with acute myocardial infarction: a population-based perspective.

BACKGROUND: Little contemporary data exist describing changes over time in the postdischarge prognosis of hospital survivors of acute myocardial infarction (AMI). The purpose of our study was to examine recent and multidecade-long (1975-2001) trends in the long-term prognosis of greater Worcester (MA) residents discharged from all metropolitan Worcester hospitals after confirmed AMI. METHODS: A total of 9827 greater Worcester residents with independently validated AMI discharged from all metropolitan Worcester hospitals during 13 annual periods between 1975 and 2001 comprised the study population. A variety of follow-up approaches were used to ascertain the survival status of discharged patients through the end of 2003. RESULTS: Crude unadjusted 1-year postdischarge survival rates declined over time. Suggestions of modest improvements in the multivariable adjusted 1-year postdischarge survival rates were noted, however, in patients discharged from greater Worcester hospitals in the more recent (2001) (adjusted odds of surviving 1.23, 95% CI 0.97-1.55) as compared with earliest study periods (1975/1978). Advancing age, female sex, presence of prior diabetes, stroke, heart failure, or myocardial infarction and occurrence of several clinical complications during hospitalization were significantly related to an adverse postdischarge prognosis. CONCLUSIONS: The results of this investigation provide contemporary insights into the long-term survival of patients with AMI from a more generalizable population-based perspective. Multivariable adjusted analyses revealed slight improvements in postdischarge survival over time. Our data identify several high-risk groups that should be targeted for more aggressive surveillance and increased use of effective cardiac therapies and interventions.

Asymptomatic valvular disease: who benefits from surgery?

Routine physical examination and noninvasive imaging frequently lead to the diagnosis of valvular heart disease in asymptomatic patients. The decision to proceed to surgical repair or replacement is based on an informed evaluation of the risks of surgery versus those encountered with a nonoperative course. In determining whether symptoms are present, stress testing may be helpful, as many patients with significant valvular lesions have a tendency to limit their daily physical exertion to levels that do not provoke symptoms. The two most feared consequences of conservative management, sudden death and permanent myocardial damage, are rare in asymptomatic patients with severe aortic stenosis or regurgitation. Surgery for asymptomatic aortic stenosis is performed only for certain high-risk subsets of patients, including those with left ventricular dysfunction, ventricular arrhythmia, and critically small valves. Asymptomatic patients with aortic regurgitation and mitral regurgitation should undergo surgery if they have systolic dysfunction or marked ventricular enlargement.

Aortic valve disease: current recommendations.

Aortic stenosis is a common valvular abnormality. Surgical valve replacement is the standard of care for symptomatic patients with severe aortic stenosis and is appropriate for certain asymptomatic patients. Statin therapy may slow progression of the disease. Contrary to conventional wisdom, vasodilator therapy may in fact be safe and effective in certain instances of severe aortic stenosis. Chronic aortic regurgitation is commonly treated with vasodilator therapy, which is certainly indicated for the asymptomatic patient with hypertension. Surgery is recommended for left ventricular dilatation, diminished ventricular systolic function, or symptoms.