Complementary pre-operative risk assessment using coronary computed tomography angiography and nuclear myocardial perfusion imaging in non-cardiac surgery: A VISION-CTA sub-study.

BACKGROUND: The incremental value and optimal utilization of non-invasive testing for prediction of peri-operative cardiac events during non-cardiac surgery are not clear. METHODS: A sub-study of VISION-CTA was performed using patients who underwent both coronary computed tomography angiography (CCTA) and nuclear myocardial perfusion imaging (MPI) as part of their pre-operative assessment. CCTA images were compared with MPI to determine the correlation between ischemia and obstructive coronary artery disease (CAD). Patients were followed post-operatively for 30 days and primary outcomes were all-cause death and non-fatal myocardial infarction. The predictive capacity of CCTA and nuclear MPI in predicting peri-operative major adverse cardiac event (MACE) was analyzed. RESULTS: A total of 55 patients (mean age 68.5 ± 8.4 years, 80.0% male) were analyzed. There was a strong correlation between the degree of obstructive CAD and the severity of perfusion abnormalities. Patients with severe CAD (≥ 70% stenosis) had a higher summed stress score than those without severe CAD [4.88 ± 1.22 and 1.30 ± 0.62, respectively (P < .05)]. Similarly summed difference score was significantly higher in patients with severe CAD [1.33 ± 0.46 and 0.17 ± 0.17 (P < .05)]. At 30 days there was a total of 8 (14.5%) MACE. The rate of MACE was higher in patients with severe CAD than those without (20.7% and 7.7%, respectively). Myocardial ischemia appeared to be predictive of MACE with an unadjusted odds ratio of 14.63 (P = .003). The predictive capacity of MPI further improved when only those patients with severe CAD were included (33.00) with a sensitivity, specificity, positive predictive value, and negative predictive value of 100% (79.4-100.0), 72.7% (49.8-89.3), 50.0% (21.1-78.9), and 100% (79.4-100.0), respectively. CONCLUSION: Although patients with significant obstructive disease are at risk of peri-operative MACE, the absolute event rate is low. Our data, albeit hypothesis generating, suggest that the peri-operative risk may be refined further by employing nuclear MPI in those with obstructive disease on CCTA.

Improved diagnostic accuracy when combining computed tomography angiography and corrected coronary opacification in patients with coronary stents.

Background The accuracy of coronary computed tomography angiography (CCTA) is sub-optimal in patients with coronary stents. Methods that can increase its diagnostic accuracy are desirable. Objective A proof-of-concept study was undertaken to determine if corrected coronary opacification (CCO) differences can improve the accuracy of CCTA in stented coronary arteries. Methods PCI patients who underwent both CCTA and invasive coronary angiography (ICA) within 3 months were analyzed. Coronary luminal attenuation values (normalized to the aorta) were measured proximally and distally to coronary stents. CCO differences were evaluated for ability to predict (i) stenosis on invasive angiography, (ii) abnormal resting coronary flow as measured by the corrected thrombolysis in myocardial infarction (TIMI) frame count (cTFC), and (iii) the combination of abnormal resting flow and significant stenosis on invasive angiography. Results Twenty-nine stented coronary arteries (n = 25, mean age =61.4 years, men =80.0%) were assessed. In stented coronary vessels, CCO identified stenosis (≥ 70%) with an area under the curve of 0.767 (P = 0.021). CCO predicted abnormal resting coronary flow with high accuracy (AUC =0.867, P = 0.002). Combined CCTA/CCO identified both abnormal cTFC and stenosis ≥70% on ICA (functionally significant stenosis) with diagnostic accuracy of 92.3%. In contrast, CCTA visual assessment alone had lower diagnostic accuracy of 66.7% for identifying functionally significant stenosis. Conclusion CCO differences are predictive of abnormal resting flow and consequently, in-stent restenosis. Incorporation of this technique may improve the specificity of CCTA in PCI patients.

Left Ventricular Thrombus as a Complication of Clozapine-Induced Cardiomyopathy: A Case Report and Brief Literature Review.

A 48-year-old male with history of schizoaffective disorder on clozapine presented with chest pain, dyspnea, and new left bundle branch block. He underwent coronary angiography, which revealed no atherosclerosis. The patient's workup was unrevealing for a cause for the cardiomyopathy and thus it was thought that clozapine was the offending agent. The patient was taken off clozapine and started on guideline directed heart failure therapy. During the course of hospitalization, he was also discovered to have a left ventricular (LV) thrombus for which he received anticoagulation. To our knowledge, this is the first case report of clozapine-induced cardiomyopathy complicated by a LV thrombus.

Cardiac PET: metabolic and functional imaging of the myocardium.

Cardiac PET has evolved over the past 30 years to gain wider acceptance as a valuable modality for a variety of cardiac conditions. Wider availability of scanners as well as changes in reimbursement policies in more recent years has further increased its use. Moreover, with the emergence of novel radionuclides as well as further advances in scanner technology, the use of cardiac PET can be expected to increase further in both clinical practice and the research arena. PET has demonstrated superior diagnostic accuracy for the diagnosis of coronary artery disease in comparison with single-photon emission tomography while it provides robust prognostic value. The addition of absolute flow quantification increases sensitivity for 3-vessel disease as well as providing incremental functional and prognostic information. Metabolic imaging using (18)F-fluorodeoxyglucose can be used to guide revascularization in the setting of heart failure and also to detect active inflammation in conditions such as cardiac sarcoidosis and within atherosclerotic plaque, improving our understanding of the processes that underlie these conditions. However, although the pace of new developments is rapid, there remains a gap in evidence for many of these advances and further studies are required.

Does rubidium-82 PET have superior accuracy to SPECT perfusion imaging for the diagnosis of obstructive coronary disease?: A systematic review and meta-analysis.

OBJECTIVES: The purpose of this study was to evaluate the accuracy of rubidium (Rb)-82 positron emission tomography (PET) for the diagnosis of obstructive coronary artery disease (CAD) in comparison to single-photon emission tomography (SPECT). BACKGROUND: Myocardial perfusion imaging is widely used in the assessment of patients with known or suspected CAD. PET using Rb-82 has potential advantages over SPECT that may make it more accurate and that reduce radiation exposure compared with SPECT but has increased costs. Comparisons of these technologies are highly relevant for policy makers and practice guidelines. However, studies directly comparing Rb-82 PET with contemporary SPECT have been limited. METHOD: The authors therefore undertook a systematic review of studies where either Rb-82 PET or technetium-99m SPECT with both attenuation correction and electrocardiography-gating were used as a diagnostic test for obstructive CAD with invasive coronary angiogram as a reference standard. These technologies were then compared. RESULTS: Fifteen PET and 8 SPECT studies (1,344 and 1,755 patients, respectively) met inclusion criteria and pooled accuracy using weighted averages according to the size of the patient population was determined for PET and SPECT with sensitivities of 90% (confidence interval [CI]: 0.88 to 0.92) and 85% (CI: 0.82 to 0.87) and specificities of 88% (CI: 0.85 to 0.91) and 85% (CI: 0.82 to 0.87), respectively. Summary receiver-operating characteristic curves were computed: area under the curve was 0.95 and 0.90 for PET and SPECT, respectively (p < 0.0001). There was heterogeneity among study populations and some studies were limited by referral bias. CONCLUSIONS: Rb-82 PET is accurate for the detection of obstructive CAD and, despite advances in SPECT technology, remains superior. More widespread use of Rb-82 PET may be beneficial to improve CAD detection.

Diastolic dysfunction in patients with end-stage liver disease is associated with development of heart failure early after liver transplantation.

BACKGROUND: Liver transplantation (LTx) is a life-saving treatment of end-stage liver disease. Cardiac complications including heart failure (HF) are among the leading causes of death after LTx. THE AIM: The aim is to identify clinical and echocardiographic predictors of developing HF after LTx. METHODS: Patients who underwent LTx at the University of Nebraska Medical Center (UNMC) between January 2001 and January 2009 and had echocardiographic study before and within 6 months after transplantation were identified. Patients with coronary artery disease (>70% lesion) were excluded. HF after LTx was defined by clinical signs, symptoms, radiographic evidence of pulmonary congestion, and echocardiographic evidence of left ventricular dysfunction (left ventricle ejection fraction <50%). RESULTS: Among 107 patients (presented as mean age [SD], 55 [10] years; male, 70%) who met the inclusion criteria, 26 (24%) patients developed HF after LTx. The pre-LTx left ventricle ejection fraction did not differ between the HF (69 [7]) and the control groups (69 [7] vs. 67 [6], P=0.30). However, pre-LTx elevation of early mitral inflow velocity/mitral annular velocity (P=0.02), increased left atrial volume index (P=0.05), and lower mean arterial pressure (P=0.03) were predictors of HF after LTx in multivariate analysis. Early mitral inflow velocity/mitral annular velocity greater than 10 and left atrial volume index 40 mL/m2 or more were associated with a 3.4-fold (confidence interval, 1.2-9.4; P=0.017) and 2.9-fold (confidence interval, 1.1-7.5; P=0.03) increase in risk of development of HF after LTx, respectively. CONCLUSIONS: This study suggests that elevated markers of diastolic dysfunction during pre-LTx echocardiographic evaluation are associated with an excess risk of HF and may predict post-LTx survival.

Assessment of cardiac computed tomography-myocardial perfusion imaging - promise and challenges - .

Cardiac computed tomography (CT) has evolved rapidly over the last decade into a reliable imaging modality for the non-invasive assessment of coronary artery disease. With the advancement in multi-detector CT technology, there has developed an increasing body of evidence that suggests that the role of cardiac CT can be extended to include functional assessment of the myocardium not only at rest but also during stress. Simultaneous anatomical and functional assessment approaches will have a number of advantages such as evaluation of the transmural extent of myocardial perfusion defects (including small subendocardial perfusion defects), reduced risk associated with multiple sources of radiation, and short image acquisition time. Although initial results hold some promise, CT myocardial perfusion imaging is a modality in the early stages of development and further work and studies are required to define, validate, and optimize this technique. This review will provide an overview of this novel perfusion imaging method, its underlying principles, evolution, limitations and future directions.

Cardiovascular implantable electronic device infection in patients with Staphylococcus aureus bacteremia.

BACKGROUND: Staphylococcus aureus bacteremia (SAB) in patients with cardiovascular implantable electronic devices (CIED), including permanent pacemakers (PPMs) and implantable cardioverter-defibrillators (ICD), can be the sole manifestation of device infection. METHODS: To assess clinical factors associated with CIED infection, we retrospectively reviewed all patients with both CIED and SAB seen at Mayo Clinic Rochester between 2001 through 2006. CIED infection was defined using microbiological and clinical criteria. RESULTS: Of the 62 patients with SAB and a CIED, 22 patients (35.5%) had CIED infection. The generator pocket was identified as the source of bacteremia in seven (11%) patients. The majority of CIED infections were device-related infective endocarditis (12 of 22, 55%). Thirty percent of patients presenting with SAB greater than 1 year after device implantation had CIED infection; all but one had CIED-related infective endocarditis. Sixty percent of ICD patients (12 of 20) with SAB had CIED infection, compared with 24% of PPM patients (10 of 42, P = 0.01). On univariate analysis factors associated with CIED-related infective endocarditis included device type [odds ratio (OR) for ICD 13.3, 95% confidence interval [CI] 2.1, 84.9) and presence of a prosthetic heart valve (OR 6.8 95% CI 1.1, 43.4). CONCLUSIONS: CIED infection is common in patients with SAB. The presence of an ICD and prosthetic heart valve were associated with CIED-related infective endocarditis. Subsequent work should focus on prospectively characterizing the subset of patients with CIED infection who present with SAB as the sole manifestation of their device infection. (PACE 2010; 407-413).