Measurement of arterial distensibility and compliance to assess prognosis.

BACKGROUND AND AIM: Total arterial compliance (TAC) reflects arterial function in the entire systemic circulation while distensibility coefficient (DC) is an estimate of local arterial compliance obtained from large elastic arteries. There are few studies relating TAC or DC to outcome. We sought whether DC or TAC predicted outcome in a primary prevention cohort with a spectrum of cardiovascular risk. METHODS: Clinical data including blood pressure (BP) and diabetes mellitus (DM) were obtained and Framingham 10-year risk was calculated in 719 primary prevention patients (373 men; age 55+/-11 years). TAC was calculated from applanation tonometry using the pulse-pressure method, 2D-echocardiography and Doppler, and DC was derived from 2D measurements of the common carotid artery and pulse pressure (PP). Cox regression analysis was performed to determine correlates of outcome. RESULTS: There were 42 deaths (5.8%) and 114 cardiovascular admissions (15.8%) over 57 months. The independent correlates of mortality were Framingham 10-year risk (HR=1.69; p<0.0001) and DC (HR=0.54; p=0.02) (model chi-square 24.52; p<0.0001) but not TAC. The independent predictors of the composite outcome of either death or admission for cardiovascular causes were Framingham 10-year risk (HR=1.28; p=0.001) and TAC (HR=0.75; p=0.006) (model chi-square 21.43; p<0.0001) but not DC. CONCLUSIONS: Measurement of arterial function is independently correlated with outcome in patients with varying degrees of cardiovascular risk, and different aspects identify fatal and non-fatal events. In addition, measurement of TAC and DC adds incremental benefit to Framingham risk scores alone in patients with intermediate cardiovascular risk.

Incremental value of strain rate analysis as an adjunct to wall-motion scoring for assessment of myocardial viability by dobutamine echocardiography: a follow-up study after revascularization.

BACKGROUND: Assessment of myocardial viability based on wall-motion scoring (WMS) during dobutamine echocardiography (DbE) is difficult and subjective. Strain-rate imaging (SRI) is quantitative, but its incremental value over WMS for prediction of functional recovery after revascularization is unclear. METHODS AND RESULTS: DbE and SRI were performed in 55 stable patients (mean age, 64+/-10 years; mean ejection fraction, 36+/-8%) with previous myocardial infarction. Viability was predicted by WMS if function augmented during low-dose DbE. SR, end-systolic strain (ESS), postsystolic strain (PSS), and timing parameters were analyzed at rest and with low-dose DbE in abnormal segments. Regional and global functional recovery was defined by side-by-side comparison of echocardiographic images before and 9 months after revascularization. Of 369 segments with abnormal resting function, 146 showed regional recovery. Compared with segments showing functional recovery, those that failed to recover had lower low-dose DbE SR, SR increment (DeltaSR), ESS, and ESS increment (DeltaESS) (each P<0.005). After optimal cutoffs for the strain parameters were defined, the sensitivity of low-dose DbE SR (78%, P=0.3), DeltaSR (80%, P=0.1), ESS (75%, P=0.6), and DeltaESS (74%, P=0.8) was better though not significantly different from WMS (73%). The specificity of WMS (77%) was similar to the SRI parameters. Combination of WMS and SRI parameters augmented the sensitivity for prediction of functional recovery above WMS alone (82% versus 73%, P=0.015; area under the curve=0.88 versus 0.73, P<0.001), although specificities were comparable (80% versus 77%, P=0.2). CONCLUSIONS: The measurement of low-dose DbE SR and DeltaSR is feasible, and their combination with WMS assessment improves the sensitivity of viability assessment with DbE.

Screening for coronary artery disease in patients with diabetes: a Bayesian strategy of clinical risk evaluation and exercise echocardiography.

OBJECTIVE: Screening for coronary artery disease is constrained by its low prevalence in unselected patients. We compared the ability of clinical scores to identify a high-risk group with diabetes mellitus and investigated a Bayesian strategy by combination with exercise echocardiography (ExE). METHODS: The Framingham risk score (FRS), a score based on the American Diabetes Association (ADA) screening guidelines, the United Kingdom Prospective Diabetes Study (UKPDS) risk engine, and a disease-specific diabetic cardiac risk score (DCRS) were calculated in 199 asymptomatic patients with type 2 diabetes mellitus undergoing ExE. The frequency of abnormal ExE and the proportion of these with coronary stenoses were sought in groups designated as high risk on the basis of optimal cutoffs for each score. All patients were followed up for 1 year. RESULTS: High risk was identified in fewer patients with the DCRS (27%) than FRS (38%, P = .02), ADA (41%, P = .004), and UKPDS (43%, P = .001). Exercise echocardiography was positive in 27 (14%); 11 of 23 proceeding to angiography showed significant stenoses. Areas under the receiver operator characteristic curves for prediction of a positive ExE were similar for DCRS, UKPDS, and FRS but less for ADA (P = .04). Positive ExE was uncommon in low-risk patients (8%-11%) and most were false positives (58%-80%). Cardiovascular events (n = 9) were more likely in the high-risk compared with the low-risk UKPDS (9% vs 2%, P = .03) and DCRS (12% vs 2%, P = .01). CONCLUSION: Combination of the UKPDS or DCRS with ExE may optimize detection of coronary artery disease and cardiac events in asymptomatic patients, while minimizing the numbers of ExE and false-positive rate.