The neural correlates of road sign knowledge and route learning in semantic dementia and Alzheimer's disease

BACKGROUND

Although there is a growing body of research on driving and Alzheimer's disease (AD), focal dementias have been understudied. Moreover, driving has never been explored in semantic dementia (SD).

METHODS

An experimental battery exploring road sign knowledge and route learning was applied to patients with SD and AD selected in the early-moderate stage of disease and to a group of healthy participants. Neuropsychological data were correlated to cerebral hypometabolism distribution, investigated by means of positron emission tomography.

RESULTS

The two dementias showed opposite profiles. Patients with SD showed poor road sign knowledge and normal performance in route learning. By contrast, patients with AD showed low performance in route learning test with preservation of semantic knowledge of road signs. In SD, there was a correlation of semantic knowledge impairment with hypometabolism in the left temporolateral cortex. No correlation between the AD region of interests (ROIs) and the relevant behavioural indices was found, while in the whole-brain analysis there was a significant correlation between route learning and the superior frontal gyrus.

DISCUSSION AND CONCLUSIONS

For the first time, driving skills were explored in SD, and it is showed a differential profile from the one detected in AD. We demonstrate that the left anterior temporal cortex is implicated in road sign knowledge, while a distributed cortical network, including the frontal cortex, is likely to process route learning.

Rest global longitudinal 2D strain to detect coronary artery disease in patients undergoing stress echocardiography: a comparison with wall-motion and coronary flow reserve responses

Myocardium subtended by obstructive coronary artery disease (CAD) may show reduced left ventricle (LV) global longitudinal strain (GLS), as well as early systolic lengthening (ESL) before shortening; these can be measured at rest and may predict obstructive CAD. This study investigated whether baseline resting LV longitudinal strain measurements may be able to detect significant CAD in patients undergoing stress echocardiography (SE) and coronary angiography, who have normal resting wall motion. We selected patients with a clinical indication of coronary angiography who were previously referred for SE. Patients with known CAD, rest wall-motion (WM) abnormalities, or rhythm/conduction abnormalities were excluded. Speckle tracking strain analyses were retrospectively performed on digitally archived 2D video-loops, using vendor independent software. Peak GLS and duration of ESL were recorded. Diagnostic accuracy of each parameter to predict obstructive (≥50%) CAD was assessed and multivariate logistic regression models fitted and compared. Eighty-two patients were enrolled and 49 had significant CAD by quantitative angiography. Patients with CAD were more often male (P=0.01) and more frequently presented with typical angina (P<0.01). Among rest and stress variables, GLS showed a Youden index of 0.665, while SE WM assessment showed a Youden index of 0.599. These were the only two parameters that remained predictive in multivariate analyses. In conclusion, rest GLS demonstrated comparable accuracy with stress-echo data for prediction of angiographically obstructive CAD; it also added significant CAD prediction when combined with clinical data, similar to SE WM assessment.

Cardiac calcium score on 2D echo: correlations with cardiac and coronary calcium at multi-detector computed tomography

Background

To test the hypothesis that a semi-quantitative echocardiographic calcium score (eCS) significantly correlates with cardiac calcium measured by coronary computed tomography angiography (CCTA) and, secondarily, severe coronary artery calcifications and stenosis.

Methods

This is a retrospective, observational study, conducted in a tertiary centre. eCS was compared with CCTA scores of non-coronary cardiac calcium (nCACS), coronary cardiac calcium (CACS) and number of diseased coronary vessels, in 141 subjects without known coronary artery disease (CAD), who underwent both echocardiography and CCTA for clinical reasons.

Results

Age, prevalence of hypertension and all measures of calcium (eCS, nCACS and CACS) differed significantly between the no-CAD and CAD subgroups. eCS was positively correlated with nCACS (Spearman rho = 0.64, p < 0.0001), CACS (rho = 0.46, p < 0.01) and weakly with the number of diseased coronary vessels (rho = 0.28, p < 0.05). eCS and nCACS had similar area under the curve (AUC) for the prediction of severe CACS (≥400) (0.77, 95% CI 0.68-0.86 and 0.79, 95% CI 0.72-0.88) or obstructive CAD (0.63, 95% CI 0.54-0.72 and 0.63, 95% CI 0.55-0.73).

Conclusions

eCS, a calcium score easily obtainable during standard echocardiography, is moderately to strongly correlated with nCACS by CCTA. The full eCS score correlates with nCACS better than its single components. It correlates with CACS and predicts severe coronary calcification (CACS > 400), a known predictor of cardiovascular morbidity and mortality. The eCS also predicts obstructive CAD, incrementally to age and clinical variables, although for this purpose CACS remains the most accurate score.

The dilemma of ischemia testing with different methods

A 52-year-old man presented after one episode of effort angina, normal treadmill electrocardiogram (ECG), and clearly positive adenosine cardiac magnetic resonance (aCMR) for reversible perfusion defects in the left anterior descending (LAD) coronary artery territory. Contrast high-dose dipyridamole (0.84 mg/kg per 6 min) stress echocardiography (cSE) demonstrated normal myocardial perfusion (MP) and wall motion at rest, while perfusion defects were shown in the lateral and apical segments after dipyridamole. Wall motion at stress was completely normal and stress/rest Doppler diastolic velocity ratio on the LAD demonstrated reduced flow reserve. In this case, cSE was the provocative test detecting both the LAD and circumflex obstructive lesions, thanks to MP analysis, while wall motion assessment was negative, not different from treadmill ECG, and aCMR highlighted only the LAD disease.

Comparative prediction of cardiac events by wall motion, wall motion plus coronary flow reserve, or myocardial perfusion analysis: a multicenter study of contrast stress echocardiography

OBJECTIVES

This study sought to determine whether the increasing difficulty of assessing wall motion (WM), Doppler coronary flow reserve on the left anterior descending coronary artery (CFR-LAD), and myocardial perfusion (MP) during stress echocardiography (SE) was justified by increasing prognostic information in patients with known or suspected coronary artery disease.

BACKGROUND

The use of echocardiographic contrast agents during SE permits the assessment of both CFR-LAD and MP, but their relative incremental prognostic value is undefined.

METHODS

This study followed a multicenter cohort of 718 patients for 16 months after high-dose dipyridamole contrast SE for evaluation of known or suspected coronary artery disease. The ability of WM, CFR-LAD, and MP to predict cardiac events was studied by multivariable models and risk reclassification.

RESULTS

Abnormal SE was detected as a reversible WM abnormality in 18%, reversible MP defect in 27%, and CFR-LAD <2 in 38% of subjects. Fifty cardiac events occurred (annualized event rate 6.0%). A normal MP stress test had a 1-year hard event rate of 1.2%. The C-index of outcomes prediction based on clinical data was improved with MP (p < 0.001) and WM/CFR-LAD (p = 0.037), and MP (p = 0.003) added to clinical and WM data. Net risk reclassification was improved by adding MP (p < 0.001) or CFR-LAD (net reclassification improvement p = 0.001) in addition to clinical and WM data. The model including clinical data, WM/CFR-LAD, and MP performed better than that without MP did (p = 0.012).

CONCLUSIONS

The multiparametric assessment of WM, CFR-LAD and MP during stress testing in patients with known or suspected coronary artery disease is feasible. Contrast SE allowed better prognostication, irrespective of the use of CFR-LAD or MP. The addition of either CFR-LAD or MP assessment to standard WM analysis and clinical parameters yielded progressively higher values for the prediction of cardiac events and may be required in today's intensively treated patients undergoing SE, because their average low risk of future cardiac events requires methods with higher predictive sensitivity than that available with standalone WM assessment.

Ejection fraction change and coronary artery disease severity: a vasodilator contrast stress-echocardiography study

BACKGROUND

An important goal of noninvasive stress testing is the identification of patients with left main coronary artery or three-vessel disease, because coronary artery disease extension and severity are major prognostic factors in ischemic heart disease. Wall motion abnormalities during vasodilator stress echocardiography become apparent in more than one coronary territory only in a small number of patients with multivessel disease. The aim of this study was to assess the value of change in left ventricular ejection fraction change (ΔLVEF) to identify patients with multivessel obstructive coronary artery disease during dipyridamole stress echocardiography.

METHODS

All dipyridamole stress echocardiographic studies performed at the authors' institution from October 2007 through March 2010 were retrospectively reviewed, and 150 patients who underwent coronary angiography within the next 60 days were selected. Left ventricular end-diastolic volume and end-systolic volume were measured at baseline and at the end of high-dose dipyridamole; ΔLVEF was calculated as stress ejection fraction minus rest ejection fraction. Patients were divided into four groups (controls and patients with single-vessel, two-vessel, and three-vessel disease) on the basis of coronary angiographic results.

RESULTS

The mean LVEF increased significantly from rest to peak stress in all groups except the three-vessel disease group. Mean ΔLVEF was negative in patients with three-vessel or left main coronary artery disease (-2.8 ± 5.1%) and significantly lower compared with all other angiographic groups (10.2 ± 5.1% and 6.2 ± 4.1%, respectively, for single-vessel and two-vessel disease). The negative value of ΔLVEF for three-vessel disease was due mainly to increased end-systolic volume at peak stress. Receiver operating characteristic curves demonstrated excellent accuracy of ΔLVEF compared with change in wall motion score index in identifying patients with multivessel disease, with areas under the curves of 0.96 and 0.62, respectively.

CONCLUSIONS

ΔLVEF is significantly lower in patients with severe coronary artery disease compared with those with single-vessel or two-vessel disease; reduced ΔLVEF identifies high-risk patients, who are likely to benefit from a more aggressive therapeutic strategy.

Contrast stress-echocardiography predicts cardiac events in patients with suspected acute coronary syndrome but nondiagnostic electrocardiogram and normal 12-hour troponin

BACKGROUND

No large study has demonstrated that any stress test can risk-stratify future hard cardiac events (cardiac death or myocardial infarction) in patients with suspected acute coronary syndromes (ACS), nondiagnostic electrocardiographic (ECG) findings, and normal troponin levels. The aim of this study was to test the hypothesis that combined contrast wall motion and myocardial perfusion echocardiographic assessment (cMCE) during stress echocardiography can predict long-term hard cardiac events in patients with suspected ACS, nondiagnostic ECG findings, and normal troponin.

METHODS

A total of 545 patients referred for contrast stress echocardiography from the emergency department for suspected ACS but nondiagnostic ECG findings and normal troponin levels at 12 hours were followed up for cardiac events. Patients underwent dipyridamole-atropine echocardiography with adjunctive myocardial perfusion imaging using a commercially available ultrasound contrast medium (SonoVue).

RESULTS

During a median follow-up period of 12 months, 25 cardiac events (4.6%) occurred (no deaths, 12 nonfatal myocardial infarctions, 13 episodes of unstable angina). Abnormal findings on cMCE were the most significant predictor of both hard cardiac events (hazard ratio, 22.8; 95% confidence interval, 2.9-176.7) and the combined (cardiac death, myocardial infarction, or unstable angina requiring revascularization) end point (hazard ratio, 10.7; 95% confidence interval, 3.7-31.3). The inclusion of the cMCE variable significantly improved multivariate models, determining lower Akaike information criterion values and higher discrimination ability.

CONCLUSIONS

cMCE during contrast stress echocardiography provided independent information for predicting hard and combined cardiac events beyond that predicted by stress wall motion abnormalities in patients with suspected ACS, nondiagnostic ECG findings, and normal troponin levels.

Severe coronary tortuosity or myocardial bridging in patients with chest pain, normal coronary arteries, and reversible myocardial perfusion defects

We reviewed patients with normal or near-normal coronary angiograms enrolled in the SPAM contrast stress echocardiographic diagnostic study in which 400 patients with chest pain syndrome of suspected cardiac origin with a clinical indication to coronary angiography were enrolled. Patients underwent dipyridamole contrast stress echocardiography (cSE) with sequential analysis of wall motion, myocardial perfusion, and Doppler coronary flow reserve before elective coronary angiography. Ninety-six patients with normal or near-normal epicardial coronary arteries were screened for the presence of 2 prespecified findings: severely tortuous coronary arteries and myocardial bridging. Patients were divided in 2 groups based on the presence (false-positive results, n = 37) or absence (true-negative results, n = 59) of reversible myocardial perfusion defects during cSE and compared for history and clinical and angiographic characteristics. Prevalence of severely tortuous coronary arteries (35% vs 5%, p <0.001) or myocardial bridging (13% vs 2%, p <0.05) was 7 times higher in patients who demonstrated reversible perfusion defects at cSE compared to those without reversible perfusion defects. No significant differences were found between the 2 groups for the main demographic variables and risk factors. Patients in the false-positive group more frequently had a history of effort angina (p <0.001) and ST-segment depression at treadmill electrocardiography (p <0.001). In conclusion, we hypothesize that patients with a positive myocardial perfusion finding at cSE but without obstructive epicardial coronary artery disease have a decreased myocardial blood flow reserve, which may be caused by a spectrum of causes other than obstructive coronary artery disease, among which severely tortuous coronary arteries/myocardial bridging may play a significant role.

Usefulness of contrast stress-echocardiography or exercise-electrocardiography to predict long-term acute coronary syndromes in patients presenting with chest pain without electrocardiographic abnormalities or 12-hour troponin elevation

The evaluation of patients presenting to the hospital with a recent episode of chest pain suggestive of myocardial ischemia, nondiagnostic electrocardiographic findings, and normal 12-hour cardiac troponin levels remains a challenge for the clinician. We selected 1,081 consecutive patients who presented to the emergency department during 2008 for a chest pain complaint of suspected cardiac origin without significant electrocardiographic abnormalities or troponin elevation. These patients underwent either contrast-enhanced stress-echocardiography with myocardial perfusion imaging or exercise-electrocardiography within 5 days of the index admission. We analyzed their 1-year cardiac outcome (i.e., unstable angina, myocardial infarction, or cardiac death). A post test likelihood of cardiac events was determined on the basis of the results of the provocative testing. Significantly better event-free survival (log-rank p <0.0001) was found for both hard (cardiac death and nonfatal myocardial infarction) and combined (acute coronary syndrome) end points in patients with normal contrast-enhanced stress-echocardiographic findings. However, this was not the case for patients in the exercise-electrocardiographic group, for whom event-free survival was not significantly different among the 3 possible result categories (normal, indeterminate, and abnormal test findings; log-rank p = NS). In conclusion, inducible ischemia detected by contrast-enhanced stress-echocardiography predicted the 1-year incidence of acute coronary syndrome (11.3% for positive vs 0.8% for negative results). However, this was not the case for exercise-electrocardiography, with a 2.7%, 2.3%, and 2.9% 1-year incidence of acute coronary syndromes for positive, negative, and indeterminate results, respectively.

Predictive value of computed tomography coronary angiography for the evaluation of acute chest pain: single center preliminary experience

AIM

To assess the predictive value of CT coronary angiography (CT-CA) in the stratification of patients with acute chest pain.

MATERIALS AND METHODS

We enrolled 48 patients (31 males and 17 females, mean age 61.0 +/- 14yrs) with acute chest pain of suspected coronary origin, without diagnostic alterations of the ECG and/or increase of the myocardial biomarkers. Sixty-four slice CT-CA was performed within 48-72 hours. Depending on the clinical judgment, the patients were dismissed or underwent conventional coronary angiography (CAG). Patients underwent clinical follow-up at 6 months, recording the prevalence of major cardiovascular events.

RESULTS

One patient was excluded from the analysis because of poor image quality. CT-CA showed no coronary artery disease in 38.3% (18/47) of the patients, no significant coronary artery disease (<50% lumen reduction) in 31.9% (15/47) of the patients, significant coronary artery disease (> or = 50% lumen reduction) in 29.8% (14/47) of the patients. In 87.2% (41/47) of the patients no indication for CAG was present. In 6 (12,8%) patients with significant stenosis at CT-CA indication for CAG was present. In 50% (3/6) of these patients, CAG showed no significant coronary artery disease and in the remaining 50%(3/6) CAG was followed by percutaneous coronary angioplasty. At follow-up no major cardiovascular events were observed.

CONCLUSIONS

CT-CA showed high sensitivity for the detection of significant coronary artery disease and a negative predictive value at 6-month follow-up.

Diagnostic accuracy of computed tomography coronary angiography in a high risk symptomatic population

OBJECTIVE

To evaluate the diagnostic accuracy of 64-slice computed tomography (CT) coronary angiography (CA) for the detection of significant coronary artery stenosis (> or = 50% lumen reduction) as compared to invasive coronary angiography (ICA) in a population of patients with chest pain and high risk.

MATERIALS AND METHODS

44 patients (30 male; mean age 60.2+/- 12.1 yrs) with chest pain were prospectively enrolled. In patients with heart rate > or = 70 bpm an oral dose of 100 mg of beta-blocker was administered. For CT-CA (Sensation 64, Siemens, Germany) an intravenous bolus of 100 ml of iodinated contrast material (Iomeron 400, Bracco, Italy) was injected. The average scan time was 13.3 +/- 0.9s. Two observers evaluated CT-CA vs. ICA as a reference standard for the detection of significant (> or = 50% lumen reduction) coronary artery stenosis.

RESULTS

ICA demonstrated the absence of coronary artery disease (CAD) in 13.6% of the patients (6/44), the presence of non significant CAD 4.6% (2/44), single vessel disease in 27.2% (12/44) and multi-vessel disease in 54.6% (24/44) of the patients. None of the patients was excluded from the study population. Ninety-three significant obstructive coronary lesions were observed. Sensitivity, specificity, positive and negative predictive value of CT-CA were 98.6% (70/71), 92.4% (97/105), 89.7% (70/78) and 99% (97/98), respectively. All patients with at least one significant coronary lesion were correctly identified by CT-CA.

CONCLUSIONS

CT-CA is a reliable alternative to ICA in a selected population of patients with chest pain and high risk.