Visual identification of coronary calcifications on attenuation correction CT improves diagnostic accuracy of SPECT/CT myocardial perfusion imaging.

BACKGROUND: Coronary artery calcium (CAC) is a powerful CAD risk marker when assessed by dedicated calcium scoring CT scan. We assessed diagnostic implications of CAC visible on attenuation correction CT scans (CTAC) from SPECT/CT myocardial perfusion imaging (MPI). METHODS: Visual presence or absence of CAC was assessed on CTAC in 1047 consecutive patients undergoing SPECT/CT MPI. Accuracy of MPI was assessed in patients undergoing invasive coronary angiography (ICA) within 1 year (n = 109). Outcomes were identified by retrospective chart review. RESULTS: Prevalence of true positive SPECT/CT MPI studies was greater among patients with CAC on CTAC (70% vs 16%; p < .001); prevalence of false positive studies was greater among those without (68% vs 15%; p < .001). PPV of MPI was 0.82 in patients with CAC, but only 0.19 in those without. Within median follow-up of 27.7 months, patients with CAC had higher all-cause mortality (6% vs 0.4%; p < .001), more late revascularizations (8% vs 0.4%; p < .001), and more MI (5% vs 0.2%; p < .001). Hazard ratio for all-cause mortality, MI, or late revascularization was 22.7 (p < .001) for patients with CAC vs those without. CONCLUSIONS: Visual assessment of CAC on CTAC should be performed during SPECT/CT MPI because it affects diagnostic certainty and may improve risk stratification.

Coronary Artery Calcifications and Cardiac Risk After Radiation Therapy for Stage III Lung Cancer.

PURPOSE: Heart dose and heart disease increase the risk for cardiac toxicity associated with radiation therapy. We hypothesized that computed tomography (CT) coronary calcifications are associated with cardiac toxicity and may help ascertain baseline heart disease. METHODS AND MATERIALS: We analyzed the cumulative incidence of cardiac events in patients with stage III non-small cell lung cancer receiving median 74 Gy on prospective dose-escalation trials. Events were defined as symptomatic effusion, pericarditis, unstable angina, infarction, significant arrhythmia, and/or heart failure. Coronary calcifications were delineated on simulation CTs using radiation software program (130 HU threshold). Calcifications were defined as "none," "low," and "high," with median volume dividing low and high. RESULTS: Of 109 patients, 26 had cardiac events at median 26 months (range, 1-84 months) after radiation therapy. Median follow-up in surviving patients was 8.8 years (range, 2.3-17.3). On simulation CTs, 64 patients (59%) had coronary calcifications with median volume 0.2 cm3 (range, 0.01-8.3). Only 16 patients (15%) had baseline coronary artery disease. Cardiac events occurred in 7% (3 of 45), 29% (9 of 31), and 42% (14 of 33) of patients with no, low, and high calcifications, respectively. Calcification burden was associated with cardiac toxicity on univariate (low vs none: hazard ratio [HR] 5.0, P = .015; high vs none: HR 8.1, P < .001) and multivariate analyses (low vs none: HR 7.0, P = .005, high vs none: HR 10.6, P < .001, heart mean dose: HR 1.1/Gy, P < .001). Four-year competing risk-adjusted event rates for no, low, and high calcifications were 4%, 23%, and 34%, respectively. CONCLUSIONS: The presence of coronary calcifications is a cardiac risk factor that can identify high-risk patients for medical referral and help guide clinicians before potentially cardiotoxic cancer treatments.

Heart dosimetric analysis of three types of cardiac toxicity in patients treated on dose-escalation trials for Stage III non-small-cell lung cancer.

BACKGROUND AND PURPOSE: To assess associations between radiation dose/volume parameters for cardiac subvolumes and different types of cardiac events in patients treated on radiation dose-escalation trials. MATERIAL AND METHODS: Patients with Stage III non-small-cell lung cancer received dose-escalated radiation (median 74 Gy) using 3D-conformal radiotherapy on six prospective trials from 1996 to 2009. Volumes analyzed included whole heart, left ventricle (LV), right atrium (RA), and left atrium (LA). Cardiac events were divided into three categories: pericardial (symptomatic effusion and pericarditis), ischemia (myocardial infarction and unstable angina), and arrhythmia. Univariable competing risks analysis was used. RESULTS: 112 patients were analyzed, with median follow-up 8.8 years for surviving patients. Nine patients had pericardial, seven patients had ischemic, and 12 patients had arrhythmic events. Pericardial events were correlated with whole heart, RA, and LA dose (eg, heart-V30 [p=0.024], RA-V30 [p=0.013], and LA-V30 [p=0.001]), but not LV dose. Ischemic events were correlated with LV and whole heart dose (eg, LV-V30 [p=0.012], heart-V30 [p=0.048]). Arrhythmic events showed borderline significant associations with RA, LA, and whole heart dose (eg, RA-V30 [p=0.082], LA-V30 [p=0.076], heart-V30 [p=0.051]). Cardiac events were associated with decreased survival on univariable analysis (p=0.008, HR 2.09), but only disease progression predicted for decreased survival on multivariable analysis. CONCLUSIONS: Cardiac events were heterogeneous and associated with distinct heart subvolume doses. These data support the hypothesis of distinct etiologies for different types of radiation-associated cardiotoxicity.

Takotsubo Cardiomyopathy and Catatonia in the Setting of Benzodiazepine Withdrawal.

We report two serious and unusual complications of benzodiazepine withdrawal in a single patient: takotsubo cardiomyopathy and catatonia. This 61-year-old female patient was brought to the emergency department with lethargy and within hours had declined into a state of catatonia. Although there was never a complaint of chest pain, ECG showed deep anterior T-wave inversions and cardiac enzymes were elevated. An echocardiogram was consistent with takotsubo cardiomyopathy. She later received 1 mg of midazolam and within minutes had resolution of catatonic symptoms. Careful history revealed that she had omitted her daily dose of lorazepam for 3 days prior to admission. To our knowledge, the case presented herein is the first report of simultaneous catatonia and takotsubo cardiomyopathy in the setting of benzodiazepine withdrawal. The pathogenesis of both conditions is poorly understood but may be indirectly related to the sudden decrease in γ-aminobutyric acid (GABA) signaling during benzodiazepine withdrawal.