Su Min Chang

Normal stress-only versus standard stress/rest myocardial perfusion imaging: similar patient mortality with reduced radiation exposure.

OBJECTIVES The aim of this study was to determine whether a normal stress-only single-photon emission computed tomographic myocardial perfusion tomography (SPECT) study confers the same prognosis as a normal SPECT on the basis of evaluation of stress and rest images. BACKGROUND Current guidelines recommend stress and rest imaging to confirm that a SPECT study is normal. METHODS We determined all-cause mortality in 16,854 consecutive patients who had a normal gated stress SPECT. Median follow-up was 4.5 years. A stress-only protocol was used in 8,034 patients (47.6%), whereas 8,820 (52.4%) had both stress and rest imaging. RESULTS The overall unadjusted annual mortality rate in patients who had a normal SPECT with a stress-only protocol was lower than in those who required additional rest imaging (2.57% vs. 2.92%, p = 0.02). After adjustment for baseline clinical characteristics no significant differences in patient mortality were seen between the 2 imaging protocols, but the stress-only group received a 61% lower radiopharmaceutical dosage. Independent predictors of worse survival included increasing age, male sex, diabetes, history of coronary artery disease, and inability to exercise (all p < 0.001) but not the type of SPECT protocol used to image patients. CONCLUSIONS Patients determined to have a normal SPECT on the basis of stress imaging alone have a similar mortality rate as those who have a normal SPECT on the basis of evaluation of both stress and rest images. Our results support that additional rest imaging is not required in patients who have a normally appearing initial stress study. A significant reduction in radiation exposure can be achieved with such an approach.

Predictive value of myocardial perfusion single-photon emission computed tomography and the impact of renal function on cardiac death.

Background— Patients with chronic kidney disease (CKD) have worse cardiovascular outcomes than those without CKD. The prognostic utility of myocardial perfusion single-photon emission CT (MPS) in patients with varying degrees of renal dysfunction and the impact of CKD on cardiac death prediction in patients undergoing MPS have not been investigated. Methods and Results— We followed up 1652 consecutive patients who underwent stress MPS (32% exercise, 95% gated) for cardiac death for a mean of 2.15±0.8 years. MPS defects were defined with a summed stress score (normal summed stress score <4, abnormal summed stress score≥4). Ischemia was defined as a summed stress score ≥4 plus a summed difference score ≥2, and scar was defined as a summed difference score <2 plus a summed stress score ≥4. Renal function was calculated with the Modified Diet in Renal Disease equation. CKD (estimated glomerular filtration rate <60 mL · min−1 · 1.73 m−2) was present in 36%. Cardiac death increased with worsening levels of perfusion defects across the entire spectrum of renal function. Presence of ischemia was independently predictive of cardiac death, all-cause mortality, and nonfatal myocardial infarction. Patients with normal MPS and CKD had higher unadjusted cardiac death event rates than those with no CKD and normal MPS (2.7% versus 0.8%, P=0.001). Multivariate Cox proportional hazards models revealed that both perfusion defects (hazard ratio 1.90, 95% CI 1.47 to 2.46) and CKD (hazard ratio 1.96, 95% CI 1.29 to 2.95) were independent predictors of cardiac death after accounting for risk factors, left ventricular dysfunction, pharmacological stress, and symptom status. Both MPS and CKD had incremental power for cardiac death prediction over baseline risk factors and left ventricular dysfunction (global &khgr;2 207.5 versus 169.3, P<0.0001). Conclusions— MPS provides effective risk stratification across the entire spectrum of renal function. Renal dysfunction is also an important independent predictor of cardiac death in patients undergoing MPS. Renal function and MPS have additive value in risk stratisfying patients with suspected coronary artery disease. Patients with CKD appear to have a relatively less benign prognosis than those without CKD, even in the presence of a normal scan.

Predictors of outcome after alcohol septal ablation therapy in patients with hypertrophic obstructive cardiomyopathy

Background—Alcohol septal ablation (ASA) therapy results in clinical and hemodynamic improvement in patients with hypertrophic obstructive cardiomyopathy. However, a subset remains symptomatic afterward, requiring additional procedures. We sought to examine the determinants of an unsatisfactory outcome, defined as unchanged symptoms with <50% reduction of baseline left ventricular outflow tract (LVOT) gradient. Methods and Results—Of 173 consecutive hypertrophic obstructive cardiomyopathy patients who underwent ASA, 39 had an unsatisfactory outcome after the first procedure. Patients with an unsatisfactory outcome had a higher baseline LVOT gradient, fewer septal arteries injected with ethanol, lower peak creatine kinase (CK), smaller septal area opacified by contrast echocardiography, and higher residual gradient in the catheterization laboratory after ASA (all P <0.05). Symptoms, septal thickness, mitral regurgitation severity, and ventricular function were not determinants of outcome. On multiple logistic regression, LVOT gradient reduction after ASA in the catheterization laboratory to ≥25 mm Hg (OR, 5.5; P =0.01) and peak CK <1300 U/L (OR, 2.5; P =0.04) were the independent predictors of an unsatisfactory outcome. Conclusions—The residual LVOT gradient in the catheterization laboratory and peak CK leak after ASA are the independent predictors of ASA outcome.

Safety of Contrast Administration for Endocardial Enhancement During Stress Echocardiography Compared With Noncontrast Stress

The aim was to evaluate the safety of stress echocardiography using contrast (CE) for endocardial enhancement compared with a noncontrast (NCE) cohort in a large nonselect population. The recent Food and Drug Administration warning cited lack of data for safety regarding the use of contrast in conjunction with stress echocardiography. A detailed record review was performed for 5,069 consecutive patients who underwent stress echocardiography (58% pharmacologic, 42% exercise) during an 8-year period. Contrast use, hemodynamics, and adverse clinical and electrocardiographic events were evaluated until time of discharge from the laboratory. Contrast was administered to 2,914 patients (58%) and was higher in in-patients (66%) and during dobutamine stress (67%). Compared with the NCE group, the CE group was older (median age 61 vs 58 years) and had more depressed left ventricular ejection fraction <50% (14% vs 11%; all p <0.001). The CE group experienced more chest pain (11% vs 8%; p = 0.001), back pain (0.6% vs 0.05%; p <0.001), and premature ventricular contractions (odds ratio 1.42, 95% confidence interval 1.19 to 1.69, p <0.001). There was no sustained ventricular tachycardia, ventricular fibrillation, cardiac arrest, or death in either group. One uncomplicated acute myocardial infarction and 1 anaphylactoid reaction occurred in the CE group, and none occurred in the NCE group (p = 0.51). Rates of clinically significant arrhythmias were similar in both groups (CE 2.1% vs NCE 1.9%; p = 0.8). In conclusion, although CE of echocardiographic images was used more often in patients with a higher cardiac risk profile, the risk of major adverse events was very small in both the CE and NCE stress echocardiography cohorts.

Functional 3D Printed Patient-Specific Modeling of Severe Aortic Stenosis

Computed tomography (CT) provides high-resolution images of the aortic valve with clear localization of calcium deposition. Three-dimensional (3D) stereolithographic printing can be used to convert these data into a physical model [(1,2)][1]. We hypothesized that patient-specific, multimaterial, 3D

Persistent left superior vena cava (PLSVC) with anomalous left hepatic vein drainage into the right atrium: role of imaging and clinical relevance

Persistent left superior vena cava (PLSVC) is a very rare and yet the most commonly described thoracic venous anomaly in medical literature. It has a 10-fold higher incidence with congenital heart disease. PLSVC often becomes apparent when an unknown PLSVC is incidentally discovered during central venous line placement, intracardiac electrode/pacemaker placement or cardiopulmonary bypass, where it may cause technical difficulties and life-threatening complications. PLSVC is also associated with disturbances of cardiac impulse formation and conduction including varying degrees of heart blocks, supraventricular arrhythmias and Wolff Parkinson White syndrome. We describe the case of an 86-year-old male with a history of coronary artery disease and chronic atrial fibrillation who presented with worsening dyspnea and syncopal episodes. An ECG was consistent with complete heart block. During lead placement for the pacemaker, a left subclavian approach was unsuccessful. A left venogram was performed through the brachial vein that demonstrated a left superior vena cava. The diagnosis was confirmed with echocardiography using a bubble study and also a chest CT. The anatomy was unique as there was anomalous left hepatic vein drainage into the right atrium. The case provides insight into the diagnostic modalities and clinical considerations of this unusual thoracic venous anomaly.

When the Worst Headache Becomes the Worst Heartache

Background and Purpose— Although a great deal of literature has been generated regarding left ventricular wall abnormalities, ECG changes and cardiac enzyme leaks associated with subarachnoid hemorrhage (SAH), there have been only a few reports of true transient left ventricular apical ballooning syndrome in patients with SAH. Several pathophysiological mechanisms have been proposed to explain the unusual features of this syndrome, such as multivessel coronary vasospasm, abnormalities in coronary microvascular function, and catecholamine-mediated cardiotoxicity. Summary of Case— A previously healthy 64-year-old woman with no history of vascular disease was found unresponsive at home. She was taken to the emergency room where a CT head revealed an SAH due to a ruptured aneurysm of the posterior communicating artery. On admission, an ECG showed deeply inverted T-waves and QT prolongation, typical of SAH. Cardiac troponin was measured at 1.2 ng/mL, and later increased to 3.7 ng/mL. A transthoracic echocardiogram on the next day revealed a large left ventricular wall abnormality, characteristic of apical ballooning with an ejection fraction of 25% to 30%. The patient remained hemodynamically stable and was started on low dose &bgr;-blocker and angiotensin-converting enzyme inhibitor. She had an uneventful cardiac recovery within 5 days at which time a repeat transthoracic echocardiogram revealed a normal ejection fraction with no wall motion abnormality. Conclusions— This report adds to the growing list of “stressors” for Takotsubo cardiomyopathy. Clinicians should be aware of the existence and the typical clinical manifestations of this syndrome, which is increasingly recognized in various populations. In particular, neurologists should consider this syndrome in the differential diagnosis of ECG changes and apical wall motion abnormalities in patients with SAH. Prognosis is generally very good with full recovery in most patients; however, there may be increased morbidity associated in patients with SAH.

Renal Function and Risk Stratification of Diabetic and Nondiabetic Patients Undergoing Evaluation for Coronary Artery Disease

OBJECTIVES The aim of this study was to evaluate the impact of renal function by estimated glomerular filtration rate (eGFR) on risk stratification of diabetic and nondiabetic patients undergoing myocardial perfusion imaging (MPI) by single-photon emission computed tomography for suspected ischemia. BACKGROUND Coronary artery disease is the leading cause of death among diabetic persons; however, diabetic persons are a very heterogeneous group in terms of cardiovascular risk, necessitating further risk stratification. METHODS Patients (n = 1,747, age 65 +/- 10 years, 37% diabetic) undergoing MPI were followed for cardiac death (CD) for a mean of 2.15 +/- 0.8 years. Chronic kidney disease (CKD) was defined by an eGFR <60 ml/min. RESULTS In the presence of a normal scan, annual CD rate was 0.9% for those with no diabetes mellitus (DM) and no CKD, 0.5% in the DM alone group, 2.35% in CKD alone, and 2.9% in those with both DM and CKD (p < 0.001). Patients with DM+CKD had a 2.7-fold risk of CD compared with no DM no CKD (p = 0.001) after controlling for age, ejection fraction, history of coronary artery disease, and other risk factors. The risk of CD increased as a function of the presence and severity of perfusion defects, regardless of CKD or DM status. Presence of CKD conferred a several-fold higher risk of CD for the various strata of perfusion defects. Log-rank test for difference in probability of CD was nonsignificant for comparison between patients with no DM no CKD and those with DM alone (p = 0.73) but was significant for comparison between patients with no DM no CKD and patients with CKD alone (p < 0.001) or DM+CKD (p < 0.001). CONCLUSIONS MPI and eGFR provide valuable risk stratification for diabetic and nondiabetic patients. Diabetic patients without CKD seem to have similar short-term cardiac outcomes compared with nondiabetic patients. Underlying CKD seems to identify a high-risk subgroup of diabetic patients.

Does quantifying epicardial and intrathoracic fat with noncontrast computed tomography improve risk stratification beyond calcium scoring alone

Background—Noncontrast cardiac computed tomography allows calculation of coronary artery calcium score (CACS) and measurement of epicardial adipose tissue (EATv) and intrathoracic fat (ITFv) volumes. It is unclear whether fat volume information contributes to risk stratification. Methods and Results—Cardiac computed tomography was performed in 760 consecutive patients with acute chest pain admitted thorough the emergency department. None had prior coronary artery disease. CACS was calculated using the Agatston method. EATv and ITFv were semiautomatically calculated. Median patient follow-up was 3.3 years. Mean patient age was 54.4±13.7 years and Framingham risk score 8.2±8.2. The 45 patients (5.9%) with major acute cardiac events (MACE) were older (64.8±13.9 versus 53.7±13.4 years), more frequently male (60% versus 40%), and had a higher median Framingham risk score (16 versus 4) and CACS (268 versus 0) versus those without events (all P<0.01). The MACE group had a higher median of EATv (154 versus 116 mL) and ITFv (330 versus 223 mL), and a higher prevalence of EATv >125 mL (67% versus 44%) and ITFv >250 mL (64% versus 42%) (all P<0.01). CACS, EATv, and ITFv were all independently associated with MACE. CACS was associated with MACE after adjustment for fat volumes (P<0.0001), whereas EATv and ITFv improved the risk model only in patients with CACS >400. Conclusions—CACS and fat volumes are independently associated with MACE in acute chest pain patients and beyond that provided by clinical information alone. Although fat volumes may add prognostic value in patients with CACS >400, CACS is most strongly correlated with outcome.

Predicting clinically unrecognized coronary artery disease: use of two- dimensional echocardiography

Background2-D Echo is often performed in patients without history of coronary artery disease (CAD). We sought to determine echo features predictive of CAD.Methods2-D Echo of 328 patients without known CAD performed within one year prior to stress myocardial SPECT and angiography were reviewed. Echo features examined were left ventricular and atrial enlargement, LV hypertrophy, wall motion abnormality (WMA), LV ejection fraction (EF) < 50%, mitral annular calcification (MAC) and aortic sclerosis/stenosis (AS). High risk myocardial perfusion abnormality (MPA) was defined as >15% LV perfusion defect or multivessel distribution. Severe coronary artery stenosis (CAS) was defined as left main, 3 VD or 2VD involving proximal LAD.ResultsThe mean age was 62 ± 13 years, 59% men, 29% diabetic (DM) and 148 (45%) had > 2 risk factors. Pharmacologic stress was performed in 109 patients (33%). MPA was present in 200 pts (60%) of which, 137 were high risk. CAS was present in 166 pts (51%), 75 were severe. Of 87 patients with WMA, 83% had MPA and 78% had CAS. Multivariate analysis identified age >65, male, inability to exercise, DM, WMA, MAC and AS as independent predictors of MPA and CAS. Independent predictors of high risk MPA and severe CAS were age, DM, inability to exercise and WMA.2-D echo findings offered incremental value over clinical information in predicting CAD by angiography. (Chi square: 360 vs. 320 p = 0.02).Conclusion2-D Echo was valuable in predicting presence of physiological and anatomical CAD in addition to clinical information.