Detection of coronary artery stenosis using 40-channel computed tomography with multi-segment reconstruction.

Coronary angiographic studies performed with 16-channel multidetector computer tomographic scanners have demonstrated accurate detection of coronary vessel stenosis but are limited by a significant number of non-evaluable segments. To date, only single-center experience with multidetector computer tomography has been reported. We performed a prospective, blinded study at 2 institutions to determine the feasibility and diagnostic accuracy of coronary angiography using 40-channel multidetector computer tomography with multi-segment reconstruction for the detection of obstructive coronary artery disease (CAD). Multidetector computer tomographic studies were performed in 85 patients who were referred for invasive coronary angiography with clinically suspected CAD. Datasets were analyzed by blinded, independent review. Of 1,145 segments that were suitable for analysis as determined by angiography, 1,045 (91.3%) were evaluable on multidetector computer tomography. Segment-based sensitivity, specificity, and positive and negative predictive values for detecting > or =50% luminal stenoses were 86%, 97%, 75%, and 97%, respectively. The area under the receiver-operating characteristic curves for the detection of > or =50% angiographic stenosis by multidetector computer tomography was 0.94. In a patient-based analysis, the sensitivity, specificity, and positive and negative predictive values for detecting subjects with > or =1 segment with > or =50% stenosis were 98%, 93%, 94% and 93%, respectively. In conclusion, coronary angiography using 40-channel multidetector computer tomography with multi-segment reconstruction accurately detects coronary segments and patients with obstructive CAD, with a small number of non-evaluable cases.

In vivo analysis of the anatomical relationship of coronary sinus to mitral annulus and left circumflex coronary artery using cardiac multidetector computed tomography: implications for percutaneous coronary sinus mitral annuloplasty.

OBJECTIVES: We sought to determine the in vivo anatomical relationships between mitral annulus (MA) and coronary sinus (CS) as well as CS and left circumflex coronary artery using cardiac computed tomography. BACKGROUND: Percutaneous treatment of mitral regurgitation (MR) by annuloplasty via CS is under development. Success of such treatment depends on the close anatomical proximity of the MA to the CS. The in vivo data regarding this anatomical relationship in humans are scant. We investigated this relationship using contrast multidetector computed tomography. METHODS: We studied 25 normal individuals and 11 patients with severe MR (3 to 4+) due to mitral valve prolapse. Separation between MA and CS was measured in standard planes, in 4-chamber (4C), 2-chamber (2C), and 3-chamber views. Distance from ostium of CS to the intersection with left circumflex (LCX), and anatomical relation of LCX and CS were determined using 3-dimensional mapping (Philips Brilliance, Philips Medical Systems, Amsterdam, the Netherlands). RESULTS: There was significant variance of CS to MA separation at all planes. Separation of CS and MA was increased in lateral location (4C) and decreased in posterior location (2C) in the MR group with increase in MA size. Left circumflex artery crossed between CS and MA in 80% of patients. The LCX crossed CS at a variable distance from the ostium of CS (86.5 +/- 21 mm, range 37 to 123 mm) CONCLUSIONS: There is significant variability in the relation of CS to MA in humans. Coronary sinus to MA distance increases in patients with severe MR and annular dilation, mainly in the posterolateral location. The left circumflex crosses under the CS the majority of times, but with a significant variability in the location where it crosses the CS. These anatomical features should be taken into consideration while selecting percutaneous treatment strategies for mitral valve repair.

Single-vessel versus multivessel territory acute ischemic stroke: value of transesophageal echocardiography in the differentiation of embolic stroke.

OBJECTIVES: We sought to assess the presence of potential aortic or cardiac sources of embolism in patients presenting with acute ischemic stroke in one or more vascular territories. BACKGROUND: In patients with acute ischemic stroke, involvement of multiple vascular territories has been used to implicate a cardiac or aortic source of embolus. It remains unclear whether patients with multivessel stroke have a higher frequency of cardiac or aortic embolic sources on transesophageal echocardiography (TEE) compared with patients with single-territory stroke. METHODS: We identified 210 patients with acute ischemic stroke documented by neuroimaging undergoing TEE for identification of a potential embolic source. Patients were divided into 3 groups (lacunar stroke, nonlacunar stroke/single-vessel involvement, nonlacunar stroke/multivessel involvement) and the frequency of potential embolic sources on TEE was compared. RESULTS: Of the 210 patients, 121 (58%) were male and the mean age was 61 years. In all, 139 patients (66%) were classified as having single-vessel stroke, 47 (22%) as having multivessel stroke, and 24 (11%) as having lacunar stroke. On TEE, 87 patients (41%) had at least one potential source of embolism. Patients with multivessel strokes had fewer potential embolic sources on TEE than patients with single-vessel or lacunar strokes (26% vs 46% and 46%, respectively; P = .043). CONCLUSIONS: In patients with acute ischemic stroke, the incidence of a potential cardiac or aortic source of embolism is high, regardless of the vascular distribution of the stroke. TEE may be a useful tool to assess the source of stroke in single-vessel, multivessel, and lacunar territory stroke distribution. We aimed to assess the presence of potential aortic or cardiac sources of embolism in patients presenting with acute ischemic stroke in one or more vascular territories. A total of 210 patients with acute ischemic stroke were divided into 3 groups (lacunar stroke, nonlacunar stroke/single-vessel involvement, nonlacunar stroke/multivessel involvement) and the frequency of potential embolic sources on transesophageal echocardiography was compared. Patients with multivessel strokes had fewer potential embolic sources on transesophageal echocardiography than patients with single-vessel or lacunar strokes, but the frequency of a potential cardiac or aortic source of embolism was high, regardless of the vascular distribution of stroke.

Use of tissue Doppler imaging to guide tube current modulation in cardiac multidetector computed tomographic angiography.

In multidetector computed tomographic coronary angiography, strategies to minimize effective radiation dose (ERD) are urgently needed. Prospective tube current modulation (TCM) allows a decrease in ERD, although it may limit reconstruction options. We sought to determine if tissue Doppler imaging (TDI) by echocardiography could predict an optimal phase for multidetector computed tomography and be used to guide TCM. Echocardiographic studies were performed in 94 patients immediately before multidetector computed tomography (83% men; mean 60 +/- 11 years of age, mean body mass index 27.7+/-4.1 kg/m2) and identified the most quiescent phase of the cardiac cycle within the atrioventricular groove. In 40 patients, prospective TCM was programmed according to TDI (TCM(TDI) group); 54 patients underwent multidetector computed tomography without TCM (no-TCM). In 25 patients assigned to the TCM(TDI) group, multidetector computed tomograms were correlated with invasive quantitative coronary angiograms to ensure maintenance of diagnostic accuracy. Optimal phase determined by TDI was 71 +/- 11%, with a distinct bi-modal distribution. Compared with no-TCM, effective radiation dose was decreased by 42% in the TCM(TDI) group (6.6 +/- 1.2 vs 11.4 +/- 2.2 mSv, p < 0.0001). Only 8 segments (3%) were unevaluable due to motion artifact. In 296 segments, sensitivity, specificity, and positive and negative predictive values to detect lesions > 50% by multidetector computed tomography were 92%, 94%, 65%, and 99%, respectively. There was good correlation between quantitative coronary angiography and multidetector computed tomography for absolute degree of stenosis (r = 0.70, p < 0.0001). In conclusion, TDI is a useful tool to guide prospective TCM in multidetector computed tomography. ERD in multidetector computed tomography may be significantly decreased using this technique while maintaining excellent image quality.

Can we reliably predict long-term mortality after exercise testing? An external validation.

OBJECTIVE: The aim of the study was to derive and externally validate a mortality prediction rule for patients undergoing exercise testing. BACKGROUND: The prognostic value of exercise testing is increasingly appreciated. However, global prognosis estimates ideally should account for numerous routinely obtained variables, including demographics, risk factors, resting electrocardiogram, and multiple exercise test measures. METHODS: A prediction rule was derived by parametric hazards modeling on a derivation set of 46047 Cleveland Clinic patients (age 55 +/- 11 years, 67% male) who had no history of heart failure, valve disease, or atrial fibrillation. Twenty-two variables covering demographics, risk factors, exercise hemodynamics, and electrocardiogram findings at rest and during exercise were considered. The resulting model included 16 variables and was tested on 4981 patients (age 50 +/- 12 years, 55% male) who underwent exercise testing at West Virginia University. RESULTS: In the derivation cohort there were 3173 deaths during a mean of 7 years of follow-up, whereas in the validation cohort there were 180 deaths during a mean of 5 years of follow-up. Comparisons of predicted and observed death rates showed very good agreement among all patients across all spectrums of risk, as well as among prespecified high-risk subgroups. Model discrimination was also good, with c statistic of c = 0.79 in the derivation group and c = 0.81 in the validation cohort. CONCLUSIONS: We have externally validated a mortality prediction rule for patients undergoing exercise testing and confirmed its accuracy among a wide spectrum of patients.

Time to move to the right--the study of right ventricular systolic performance: too long neglected.

Although the evidence that right ventricular (RV) function has significant impact on cardiac hemodynamics and outcome is indisputable, its evaluation has been hampered by problems with image quality, geometric variability, and the absence of a standard of reference. A resurgence of research activity has sought to discern the pathophysiology of RV dysfunction and to explore new methods for measuring performance. Noninvasive techniques such as tissue Doppler echocardiography, three-dimensional echocardiography, and magnetic resonance imaging provide new quantitative information and may improve prediction of outcomes. These advances in technology, and the recognition that RV systolic function is essential in many conditions, provide the impetus for future studies. This review highlights the past and present efforts to incorporate RV systolic function into the mainstream of cardiology practice.