Robert Fathi

Does renal failure cause an atherosclerotic milieu in patients with end-stage renal disease?☆

PURPOSE Atherosclerotic vascular disease is the main cause of morbidity and mortality in patients with end-stage renal disease, but the independent contribution of renal failure rather than associated risk factors is unclear. We sought to examine the relative contribution of these factors to the severity of atherosclerosis by measuring intima-medial thickness and brachial artery reactivity in uremic patients and controls. SUBJECTS AND METHODS Cardiovascular risk factors, including lipid and homocysteine levels, were evaluated in 213 patients (69 on hemodialysis, 60 on peritoneal dialysis, and 82 nonuremic controls). High-resolution B-mode ultrasonography with automated off-line analysis was used to measure the intima-medial thickness in the common carotid artery and to measure the lumen diameter of the brachial artery at rest, during reactive hyperemia, and after sublingual nitroglycerine. The correlations of risk factors with intima-medial thickness and brachial reactivity were examined using a general linear regression model. RESULTS Patients with renal failure had a greater mean (+/- SEM) maximum intima-medial thickness than controls (0.83 +/- 0.02 mm versus 0.70 +/- 0.02 mm, P < 0.05), but the brachial artery response to reactive hyperemia was not significantly different between the renal failure patients and the control group (4.7% +/- 6.1% versus 6.1% +/- 8.6% dilatation, P > 0.05). The uremic state was an independent predictor of intima-medial thickness (r2 = 0.16, P < 0.001) but not of brachial artery reactivity (P = 0.99). CONCLUSION The atherosclerotic burden in patients with renal failure, as indicated by an increased intima-medial thickness, may reflect effects of uremia that are independent of cardiovascular risk factors.

Incremental benefit of myocardial contrast to combined dipyridamole–exercise stress echocardiography for the assessment of coronary artery disease

Background—Although assessment of myocardial perfusion by myocardial contrast echocardiography (MCE) is feasible, its incremental benefit to stress echocardiography is not well defined. We examined whether the addition of MCE to combined dipyridamole-exercise echocardiography (DExE) provides incremental benefit for evaluation of coronary artery disease (CAD). Methods and Results—MCE was combined with DExE in 85 patients, 70 of whom were undergoing quantitative coronary angiography and 15 patients with a low probability of CAD. MCE was acquired by low-mechanical-index imaging in 3 apical views after acquisition of standard resting and poststress images. Wall motion, left ventricular opacification, and MCE components of the study were interpreted sequentially, blinded to other data. Significant (>50%) stenoses were present in 43 patients and involved 69 coronary territories. The addition of qualitative MCE improved sensitivity for the detection of CAD (91% versus 74%, P=0.02) and accurate recognition of disease extent (87% versus 65% of territories, P=0.003), with a nonsignificant reduction in specificity. Conclusions—The addition of low-mechanical-index MCE to standard imaging during DExE improves detection of CAD and enables a more accurate determination of disease extent.

Effect of tissue Doppler on the accuracy of novice and expert interpreters of dobutamine echocardiography

The subjective interpretation of dobutamine echocardiography (DBE) makes the accuracy of this technique dependent on the experience of the observer, and also poses problems of concordance between observers. Myocardial tissue Doppler velocity (MDV) may offer a quantitative technique for identification of coronary artery disease, but it is unclear whether this parameter could improve the results of less expert readers and in segments with low interobserver concordance. The aim of this study was to find whether MDV improved the accuracy of wall motion scoring in novice readers, experienced echocardiographers, and experts in stress echocardiography, and to identify the optimal means of integrating these tissue Doppler data in 77 patients who underwent DBE and angiography. New or worsening abnormalities were identified as ischemia and abnormalities seen at rest as scarring. Segmental MDV was measured independently and previously derived cutoffs were applied to categorize segments as normal or abnormal. Five strategies were used to combine MDV and wall motion score, and the results of each reader using each strategy were compared with quantitative coronary angiography. The accuracy of wall motion scoring by novice (68 +/- 3%) and experienced echocardiographers (71 +/- 3%) was less than experts in stress echocardiography (88 +/- 3%, p <0.001). Various strategies for integration with MDV significantly improved the accuracy of wall motion scoring by novices from 75 +/- 2% to 77 +/- 5% (p <0.01). Among the experienced group, accuracy improved from 74 +/- 2% to 77 +/- 5% (p <0.05), but in the experts, no improvement was seen from their baseline accuracy. Integration with MDV also improved discordance related to the basal segments. Thus, use of MDV in all segments or MDV in all segments with wall motion scoring in the apex offers an improvement in sensitivity and accuracy with minimal compromise in specificity.

Correlates of subclinical left ventricular dysfunction in ESRD

BACKGROUND Abnormalities of the left ventricle are common in patients with end-stage renal disease (ESRD) both before and after the start of renal replacement therapy. The purpose of this study is to identify possible causes of subclinical left ventricular (LV) dysfunction in patients with ESRD. In particular, we sought to determine whether the presence of ESRD was itself associated with dysfunction independent of LV hypertrophy and coronary artery disease. METHODS Assessment of cardiovascular risk factors and dialysis adequacy was completed in 145 unselected patients with ESRD who were recruited from the renal dialysis unit and compared with age- and sex-matched controls. Among the 68 patients with ESRD who had undergone a dobutamine stress echocardiogram with normal findings, regional cardiac function was quantified by myocardial Doppler velocity, LV volumes and mass were measured using three-dimensional echocardiography, and vascular function was assessed using brachial artery reactivity (BAR). RESULTS LV diastolic velocity was impaired in patients with ESRD, but there was no significant difference in systolic velocity compared with control patients of similar age. Age, diabetes mellitus, hypertension, and LV mass were independent predictors of diastolic velocity (model R2 = 0.45; P < 0.001), whereas age and risk factor number were predictors of systolic velocity (model R2 = 0.19; P = 0.002). Increasing risk factor number had no significant relationship with LV mass or volume. There was no detected association between BAR and incremental risk factors (P = 0.51). CONCLUSION Subclinical LV dysfunction occurs in patients with ESRD, but is evidenced as abnormal myocardial diastolic, rather than systolic, function. Correlates of abnormal function are age, diabetes mellitus, hypertension, and LV mass, rather than ESRD alone, dialysis adequacy, or abnormal endothelial function.

A randomized trial of aggressive lipid reduction for improvement of myocardial ischemia, symptom status, and vascular function in patients with coronary artery disease not amenable to intervention

PURPOSE To determine the effects of aggressive lipid lowering on markers of ischemia, resistance vessel function, atherosclerotic burden, and symptom status in patients with symptomatic coronary artery disease. METHODS Sixty consecutive patients with coronary artery disease that was unsuitable for revascularization were assigned randomly to either usual therapy of lipids for patients with a low-density lipoprotein (LDL) cholesterol target level <116 mg/dL, or to a more aggressive lipid-lowering strategy involving up to 80 mg/d of atorvastatin, with a target LDL cholesterol level <77 mg/dL. The extent and severity of inducible ischemia (by dobutamine echocardiography), vascular function (brachial artery reactivity), atheroma burden (carotid intima-media thickness), and symptom status were evaluated blindly at baseline and after 12 weeks of treatment. RESULTS After 12 weeks of treatment, patients in the aggressive therapy group had a significantly greater decrease in mean (+/- SD) LDL cholesterol level than those in the usual care group (29 +/- 38 mg/dL vs. 7 +/- 24 mg/dL, P = 0.03). Patients in the aggressive therapy group had a reduction in the number of ischemic wall segments (mean between-group difference of 1.3; 95% confidence interval: 0.1 to 2.0; P = 0.04), flow-mediated dilatation (mean between-group difference of 5.9%; 95% confidence interval: 2.5% to 9.4%; P = 0.001), and angina score after 12 weeks. There were no significant changes in atherosclerotic burden in either group. CONCLUSION Patients with symptomatic coronary artery disease who are treated with aggressive lipid lowering have improvement of symptom status and ischemia that appears to reflect improved vascular function but not atheroma burden.

Effects of revascularisation and contractile reserve on left ventricular remodelling in patients with impaired left ventricular function

OBJECTIVE We sought to define the influence of revascularisation and contractile reserve on left ventricular (LV) remodelling in patients with LV dysfunction after myocardial infarction. Revascularisation of viable myocardium is associated with improved regional function, but the effect on remodelling is undefined. METHODS We studied 70 patients with coronary artery disease and LV dysfunction, 31 of whom underwent revascularisation. A standard dobutamine stress echocardiogram (DbE) was carried out. All patients underwent standard medical treatment; the decision to revascularise was made clinically, independent of this study. LV volumes and ejection fraction were measured by 3D echocardiography at baseline and after an average of 40 weeks. RESULTS There was no significant difference in baseline ejection fraction or volumes between patients who underwent revascularisation and the remainder. Compared to medically treated patients, revascularised patients had significant improvements in ejection fraction and end-systolic volume in follow-up. The impact of baseline variables on remodelling was assessed by dividing patients into tertiles of LV ejection fraction and volumes. Revascularised patients in the lowest tertile of ejection fraction at baseline (<38%) had a significant improvement in end-systolic volume and ejection fraction, larger than obtained in medically treated patients with low ejection fraction. Revascularised patients with an ejection fraction >38% did not show significant improvement in volumes compared to baseline. Revascularised patients in the largest tertiles of end-systolic (>88 ml) or end-diastolic volume (>149 ml) at baseline had a significant improvement in end-systolic volume. CONCLUSION Remodeling appears to occur independent of the presence of regional contractile reserve but does correlate with the volume response to low-dose dobutamine.

Influence of arterial compliance on presence and extent of ischaemia during stress echocardiography

Objective: To seek an association between total arterial compliance (TAC) and the extent of ischaemia at stress echocardiography. Design: Cohort study. Setting: Regional cardiac centre. Methods: 255 consecutive patients (147 men; mean (SD) age 58 (8)) presenting for stress echocardiography for clinical indications were studied. Wall motion score index (WMSI) was calculated and ischaemia was defined by an inducible or worsening wall motion abnormality. Peak WMSI was used to reflect the extent of dysfunction (ischaemia or scar), and ΔWMSI was indicative of extent of ischaemia. TAC was assessed at rest by simultaneous radial applanation tonometry and pulsed wave Doppler in all patients. Results: Ischaemia was identified by stress echocardiography in 65 patients (25%). TAC was similar in the groups with negative and positive echocardiograms (1.08 (0.41) v 1.17 (0.51) ml/mm Hg, not significant). However, the extent of dysfunction was associated with TAC independently of age, blood pressure, risk factors, and use of a β blocker. Moreover, the extent of ischaemia was determined by TAC, risk factors, and use of a β blocker. Conclusion: While traditional cardiovascular risk factors are strong predictors of ischaemia on stress echocardiography, TAC is an independent predictor of the extent of ischaemia.

Procedural Tips and Tricks

Of all peripheral vascular interventions, carotid artery stenting (CAS) remains the procedure with the steepest learning curve and the lowest margin for error. The procedure demands a meticulous approach, advanced catheter and guidewire skills, an excellent appreciation of neuroanatomy, and the ability to manage dynamic fluctuations in hemo-dynamic status. Of perhaps greater importance is the decision-making and judgment necessary for appropriate patient selection.

Red cell velocity and myocardial blood volume are clinically feasible markers for quantitative myocardial contrast stress echocardiography

Background. Although the evidence for applying specialist nurse-led programs of care to optimise the postdischarge management of chronic heart failure (CHF) is compelling, the majority of randomised studies have either applied a clinic or home-based approach. In practice, however, many programs employ a pragmatic combination of the two.

Is gender an independent determinant of total arterial compliance

Background. Although the evidence for applying specialist nurse-led programs of care to optimise the postdischarge management of chronic heart failure (CHF) is compelling, the majority of randomised studies have either applied a clinic or home-based approach. In practice, however, many programs employ a pragmatic combination of the two.