Clinical effectiveness of coronary computed tomographic angiography in the triage of patients to cardiac catheterization and revascularization after inconclusive stress testing: results of a 2-year prospective trial.

BACKGROUND: Management of patients with suspected coronary artery disease (CAD) and inconclusive stress imaging test findings may result in invasive coronary angiography (ICA). Coronary computed tomographic angiography (CCTA) may be useful in defining the risk of CAD and adverse outcomes in this patient population, as well as in reducing the need for ICA. METHODS: We prospectively enrolled 199 sequential patients referred by cardiologists for CCTA after either inconclusive or nondiagnostic stress imaging tests. Before CCTA, physicians identified a "planned catheterization" group of patients who would undergo invasive angiography if CCTA were not available. After CCTA testing, patients were followed for >or=2 years. We established the added diagnostic value of the CCTA and its prognostic power in prediction of intermediate-term follow-up events in this patient population as compared to available historical and clinical predictors of CAD, stress ECG, and stress imaging test results using a multivariable Cox proportional hazards survival analysis. RESULTS: Both observed data and results of the multivariable model for the prediction of obstructive CAD (>50% stenosis), or major cardiac events (death MI or revascularization), demonstrated that clinical, stress ECG, and imaging results were weakly predictive, whereas CCTA was found to be a strong independent and incremental predictor of the absence of either significant CAD or MACE in this population. None of the 93 patients with normal CCTA scans had MACE events, whereas 18 patients with evidence of CAD on the CCTA results underwent revascularization. Overall, physicians planned ICA in 125 patients (63.0%); after CCTA, ICA was performed in only 32 (16.0%) cases over 2 years. In this population with no other highly effective noninvasive clinical tools for diagnostic and prognostic estimation, the overall negative predictive value of CCTA for either CAD > 50% or MACE for 2 years was 99%. CONCLUSION: Observations from this prospective study demonstrate the significant added diagnostic value and prognostic potential of CCTA in patients with suspected CAD and either inconclusive or nondiagnostic stress test results in real-world settings. Normal CCTA results are associated with excellent intermediate-term prognosis in this clinical subset, and invasive angiography can be safely avoided in the majority of these patients when the results of CCTA are available.

Improved noninvasive coronary angiography in morbidly obese patients with dual-source computed tomography.

BACKGROUND: Morbidly obese persons (body mass index [BMI; in kg/m(2)] >or= 40) have an increased risk of cardiovascular morbidity and mortality but have reduced accuracy with conventional cardiac testing and coronary CT angiography (CCTA). OBJECTIVE: This study investigated a novel dual-source computed tomography (DSCT) acquisition and reconstruction method for coronary imaging in morbidly obese patients. METHODS: This was a observational study in which each patient served as his or her own control. After a single DSCT acquisition using a novel method, standard quarter-scan image reconstructions at a temporal resolution of 83 milliseconds were compared with temporal resolution reconstructions at 105, 125, and 165 milliseconds. Images were evaluated for diagnostic adequacy score and for image noise, signal-to-noise ratio, and contrast-to-noise ratio. In each patient, the image reconstruction with the best visual diagnostic score was compared with the control image for quantitative measures. RESULTS: Fifty patients (32 female; mean +/- SD age, 51 +/- 10 y; mean BMI, 44.8 +/- 5.6) were enrolled. Scans were of diagnostic quality in 47 (94%) patients using the "best reconstruction" compared with 38 (76%) patients using quarter-scan reconstruction. Significant improvements were observed in noise (42 +/- 16 HU versus 56 +/- 19 HU; P < 0.0001), contrast-to-noise ratio (8.4 +/- 3.3 HU versus 7.0 +/- 2.2 HU; P = 0.0038), and signal-to-noise ratio (7.6 +/- 2.9 HU versus 6.5 +/- 3.5 HU; P = 0.030). CONCLUSIONS: CCTA with DSCT using a modified scan protocol and adjustable temporal reconstructions provides diagnostic image quality in >90% of morbidly obese patients.

Electrocardiographic responses to deer hunting activities in men with and without coronary artery disease.

To evaluate the cardiac demands of hunting deer, continuous ambulatory electrocardiograms were obtained in men with and without coronary artery disease (CAD) and compared with their responses to maximal treadmill testing. A volunteer sample of 25 middle-aged men (mean +/- SD 55 +/- 7 years of age), 17 of whom had known CAD, completed the study. Peak heart rate (HR) during 7 different deer hunting activities was expressed as the mean percentage of the maximal HR (HRmax) attained during treadmill testing. Periods of sustained sinus tachycardia were identified. Arrhythmias and ST-segment depression during deer hunting that were not apparent during treadmill testing were documented. Overall, 22 of 25 subjects demonstrated HR responses >85% HRmax for 1 to 65 minutes. Ten subjects exceeded the HRmax achieved during treadmill testing for 1 to 5 minutes. The relative HR response during ambulatory activity in the field was inversely related to cardiorespiratory fitness, expressed as METs (r = -0.59; p = 0.0020). Three subjects had ischemic electrocardiograms during deer hunting, but not during treadmill testing. Complex arrhythmias in the field not detected by treadmill testing included ventricular bi-trigeminy, ventricular couplets, and 8 runs of ventricular tachycardia (3 to 28 beats) in 3 subjects with documented CAD. In conclusion, deer hunting can evoke sustained HRs, ischemic ST-segment depression, and threatening ventricular arrhythmias in excess of those documented during maximal treadmill testing. The strenuous nature of deer hunting coupled with presumed hyperadrenergia and superimposed environmental stresses may contribute to the excessive cardiac demands associated with this activity.