The non-invasive documentation of coronary microcirculation impairment: role of transthoracic echocardiography

Non Invasive Detection of Coronary Sinus Flow Changes Over Time After CABG

Background

Coronary New blood in the vascular bed after Coronary Artery Bypass Grafting (CABG) may represent a turning point between ischemia and normal tissue nutrition. Its quantification can help to better understand coronary artery hemodynamics after revascularization.

Objective

Quantification of coronary sinus blood flow changes over time after Coronary Artery Bypass Grafting (CABG) using Transthoracic Echocardiography (TTE).

Methods

Prospective basic research, with repeated measurements on hospital sample of 61 patients whom CABG was conducted. We performed TTE recordings to measure CS flow before and two times after CABG (1 and 6 postoperative day). We measure CS diameter, Velocity Time Integral (VTI) and systemic hemodynamic data. Data needed for LV mass calculation were recorded once. During statistical analysis we define: α = 0,01, β = 0,01 (power = 1-β β= 0,99), Sample size = 60, Effect size= 0,68. We used ANOVA for Repeated Measures as main statistical test in SPSS.

Results

Preoperatively we found low overall CS flow of 181 ±72 ml/min (0,68 ±0,30 ml/gram-LV/min). After surgery there was constant increase of CS flow from 276 ±79 ml/min (1,13 ±0,35 ml/gram-LV/min) first postoperative day, to 355 (±99) ml/min (1,30 ±0,46 ml/gram-LV/min) sixth postoperative day.

Discussion

Amount of new blood was statistically significant after CABG with P<0,001. Same result was found after classifying patients per number of graft received, with the highest amount of new blood after four bypasses. Amount of new blood was not different if patient gets two or three bypasses.

Conclusion

There was significantly new amount of blood in coronary bed after CABG, with constant increase over first 6 days.

Coronary Flow Velocity Reserve and Myocardial Deformation Predict Long-Term Outcomes in Heart Transplant Recipients

BACKGROUND

After heart transplantation (HTx), invasive coronary angiography is the gold standard for surveillance of cardiac allograft vasculopathy (CAV). Noninvasive CAV surveillance is desirable. The authors examined left ventricular global longitudinal strain (LVGLS) and noninvasive coronary flow velocity reserve (CFVR) related to CAV and prognosis after HTx.

METHODS

Doppler echocardiographic CFVR and LVGLS were evaluated in 98 HTx patients. All-cause mortality and major adverse cardiac events (MACE), including hospitalization for heart failure, cardiovascular death, and significant CAV progression, were recorded.

RESULTS

Median follow-up duration was 3.3 years (range: 1.7-5.4 years). Patients with low CFVR (<2.0; n = 20) showed reduced MACE-free survival (hazard ratio, 4.3; 95% CI, 2.2-8.4; P < .0001) and increased all-cause mortality (hazard ratio: 4.7; 95% CI: 2.0-11.3; P < .0001) compared with patients with high CFVR (≥2.0; n = 78). Worsened LVGLS (≥-15.5%) was also a strong independent predictor of MACE and cardiovascular and all-cause mortality. Combined low CFVR and worsened LVGLS provided incremental prognostic value, even after adjustment for CAV and time since HTx. The prevalence of low CFVR increased significantly with CAV severity, and the prevalence of combined low CFVR and/or worsened LVGLS was high in patients with moderate CAV (86%) and those with severe CAV (83%). The negative predictive value of combined high CFVR and improved LVGLS to rule out significant CAV was 94.5% (95% CI, 86.2%-98.4%), whereas the positive predictive value was 39.0% (95% CI, 25.3%-54.3%). The model had sensitivity of 84.2% (95% CI, 63.6%-95.3%) and specificity of 67.5% (95% CI, 56.6%-77.2%) for one or more abnormal parameters.

CONCLUSIONS

In HTx patients with severe CAV, a higher prevalence of low CFVR and worsened LVGLS was observed. Both measurements were strong independent predictors of MACE and all-cause mortality in HTx patients. Combined CFVR and LVGLS provided incremental prognostic value and showed an excellent ability to rule out significant CAV and may be considered as part of routine CAV surveillance of HTx patients.

Epidemiology, Pathophysiology, Diagnosis and Treatment of Heart Failure in Diabetes

The cardiovascular disease continuum begins with risk factors such as diabetes mellitus (DM), progresses to vasculopathy and myocardial dysfunction, and finally ends with cardiovascular death. Diabetes is associated with a 2- to 4-fold increased risk for heart failure (HF). Moreover, HF patients with DM have a worse prognosis than those without DM. Diabetes can cause myocardial ischemia via micro- and macrovasculopathy and can directly exert deleterious effects on the myocardium. Hyperglycemia, hyperinsulinemia, and insulin resistance can cause alterations in vascular homeostasis. Then, reduced nitric oxide and increased reactive oxygen species levels favor inflammation leading to atherothrombotic progression and myocardial dysfunction. The classification, diagnosis, and treatment of HF for a patient with and without DM remain the same. Until now, drugs targeting neurohumoral and metabolic pathways improved mortality and morbidity in HF with reduced ejection fraction (HFrEF). Therefore, all HFrEF patients should receive guideline-directed medical therapy. By contrast, drugs modulating neurohumoral activity did not improve survival in HF with preserved ejection fraction (HFpEF) patients. Trials investigating whether sodium-glucose cotransporter-2 inhibitors are effective in HFpEF are on-going. This review will summarize the epidemiology, pathophysiology, and treatment of HF in diabetes.

Myocardial strain indices and coronary flow reserve are only mildly affected in healthy hypertensive patients

To investigate changes in two-dimensional myocardial strain echocardiography (2DSTE) indices following a dipyridamole stress test (DIPSE) in relatively healthy hypertensive patients and healthy controls. Forty-seven male hypertensive patients (aged 57±9 years) with normal ejection fraction and without left ventricular (LV) hypertrophy and 20 healthy male subjects were studied with conventional and 2DSTE echocardiography at rest and post DIPSE. Coronary flow reserve (CFR) in the left anterior descending artery following DIPSE was also evaluated. Global longitudinal strain (GLS) and TWIST were higher while UNTWIST rate was lower in hypertensives versus controls (p < 0.05 for all); TWIST remained higher in hypertensives (p = 0.021) after adjustment for differences in age and body mass index (BMI) between the groups. CFR was higher in controls compared to hypertensives even after adjustment for confounders (4.14 vs. 2.53, p = 0.001). DIPSE-induced changes did not differ between the groups after adjustment for age and BMI (p > 0.05 for all). DIPSE-induced improvement in GLS was associated with higher CFR only in hypertensive patients (r - 0.372, p = 0.010). The current study showed that well controlled hypertensive patients have only mild echocardiographic differences compared to controls; some of these differences appear to depend on age and BMI. A 'hyper-rotation' phenomenon (i.e. higher TWIST) early in hypertension may be a compensatory mechanism to preserve global systolic LV function. Coronary microcirculatory function was impaired in hypertensive patients, albeit within normal range, and was associated with DIPSE-induced changes in myocardial long-axis systolic function.

Effect of Hyperglycemia on Myocardial Perfusion in Diabetic Porcine Models and Humans

BACKGROUND

Diabetes mellitus (DM) causes macro- and microvasculopathy, but data on cardiac microvascular changes in large animals are scarce. We sought to determine the effect of DM on macro- and microvascular changes in diabetic pigs and humans.

METHODS

Eight domestic pigs (4 with type I diabetes and 4 controls) underwent coronary angiography with optical coherence tomography (OCT; at baseline and 1 and 2 months), coronary computed tomography angiography, cardiac magnet resonance (CMR) imaging, and histologic examination.

RESULTS

The diabetic pigs had more irregular capillaries with acellular capillaries and a smaller capillary diameter (11.7 ± 0.33 μm vs. 13.5 ± 0.53 μm; P < 0.001) than those of the control pigs. The OCT showed no significant epicardial stenosis in either group; however diabetic pigs had a greater intima-media thickness. CMR results showed that diabetic pigs had a lower relative upslope at rest (31.3 ± 5.9 vs. 37.9 ± 8.1; P = 0.011) and during stress (18.0 ± 3.0 vs. 21.6 ± 2.8; P = 0.007) than the control pigs, implying decreased myocardial perfusion. Among the 79 patients with ST elevation myocardial infarction, 25 had diabetes and they had lower myocardial perfusion on CMR as well.

CONCLUSION

DM causes microvascular remodeling and a decrease in myocardial perfusion in large animals at a very early stage of the disease course. Early and effective interventions are necessary to interrupt the progression of vascular complications in diabetic patients.

Reduced global myocardial perfusion reserve in DCM and HCM patients assessed by CMR-based velocity-encoded coronary sinus flow measurements and first-pass perfusion imaging

BACKGROUND

Coronary microvascular dysfunction (CMD) is an independent predictor of poor prognosis in patients suffering from dilative or hypertrophic cardiomyopathy (DCM/HCM). To assess CMD, quantitative myocardial first-pass perfusion (1P) cardiovascular magnetic resonance (CMR) can be performed. Coronary sinus flow (CSF) measurements at rest and during maximal vasodilatation are an alternative and well-validated approach for the quantification of global myocardial blood flow (MBF) in CMR.

METHODS

Global myocardial perfusion reserve (MPR) was used to compare both methods, 1P and CSF. This measure reflects the ratio of myocardial blood flow during maximal coronary vasodilatation over rest. 1P-MPR and CSF-MPR were calculated in 17 HCM patients, 14 DCM patients and 16 controls, who underwent a stress CMR study to rule out obstructive coronary artery disease. All patients were examined on a 1.5-T system and the study protocol comprised both, first-pass myocardial perfusion imaging (MPI) and velocity-encoded (VENC) phase-contrast imaging of CSF during rest and adenosine stress.

RESULTS

1P-MPR was significantly decreased only in HCM patients compared to controls (1.14 vs. 1.43, p = 0.045) whereas CSF-MPR was significantly reduced in both patient groups, HCM and DCM, compared to controls (2.38 and 2.07 vs. 3.18, p = 0.041 and p = 0.032). CSF-MBF at maximal stress was significantly lower in HCM and DCM patients compared to the control group (0.11 and 1.23 vs. 1.58 ml/min/g, p = 0.008 and p = 0.040). A moderate but significant correlation between CSF-MPR and 1P-MPR was observed (r = 0.39, p = 0.011). A negative correlation between LV wall thickness and CSF-MBF at rest and stress was found in the DCM group using VENC-based CSF measurements (r = - 0.64, p = 0.013 and r = - 0.69, p = 0.006)-but not using 1P-MPI. Post-proceeding analysis regarding 1P-MPR and CSF-MPR measurements required 20.1 and 6.5 min, respectively (p < 0.001).

CONCLUSION

The presence of microvascular disease can be non-invasively and quickly detected by VENC-based CSF-MPR measurements during routine stress perfusion CMR in both HCM and DCM patients. Compared to conventional 1P-MPI, VENC-based CSF-MPR is particularly useful in DCM patients with thinned ventricular walls.

Hyperglycemia Induced by Glucokinase Deficiency Accelerates Atherosclerosis Development and Impairs Lesion Regression in Combined Heterozygous Glucokinase and the Apolipoprotein E-Knockout Mice

Aim. Models combining diabetes and atherosclerosis are important in evaluating the cardiovascular (CV) effects and safety of antidiabetes drugs in the development of treatments targeting CV complications. Our aim was to evaluate if crossing the heterozygous glucokinase knockout mouse (GK+/-) and hyperlipidemic mouse deficient in apolipoprotein E (ApoE-/-) will generate a disease model exhibiting a diabetic and macrovascular phenotype. Methods. The effects of defective glucokinase on the glucose metabolism and on the progression and regression of atherosclerosis on high-fat diets were studied in both genders of GK+/-ApoE-/- and ApoE-/- mice. Coronary vascular function of the female GK+/-ApoE-/- and ApoE-/- mice was also investigated. Results. GK+/-ApoE-/- mice show a stable hyperglycemia which was increased on Western diet. In oral glucose tolerance test, GK+/-ApoE-/- mice showed significant glucose intolerance and impaired glucose-stimulated insulin secretion. Plasma lipids were comparable with ApoE-/- mice; nevertheless the GK+/-ApoE-/- mice showed slightly increased atherosclerosis development. Conclusions. The GK+/-ApoE-/- mice showed a stable and reproducible hyperglycemia, accelerated atherosclerotic lesion progression, and no lesion regression after lipid lowering. This novel model provides a promising tool for drug discovery, enabling the evaluation of compound effects against both diabetic and cardiovascular endpoints simultaneously in one animal model.

Positive effects of aggressive vasodilator treatment of well-treated essential hypertensive patients

Increased systemic vascular resistance and coronary microvascular dysfunction are well-documented in essential hypertension (EH). We investigated the effect of additional vasodilating treatment on coronary and peripheral resistance circulation in EH patients with high systemic vascular resistance index (SVRI) despite well-treated blood pressure (BP). We enroled patients on stable antihypertensive treatment that were given intensified vasodilating therapy (ACE inhibitor, angiotensin II receptor blocker or calcium channel blocker). Before and following 6 months of intensified therapy, coronary resting and maximal artery flow were measured by transthoracic Doppler echocardiography to calculate coronary flow reserve (CFR) and minimum vascular resistance (C-R_min). Cardiac output was estimated by inert gas rebreathing to calculate SVRI. Maximal forearm blood flow was determined by venous occlusion plethysmography to calculate minimum vascular resistance (F-R_min). Patients were assigned into two groups: high-SVRI and low-SVRI subgroups, based on a median split at baseline. Following additional treatment SVRI decreased more in the high-SVRI group than in the low-SVRI group (14.4 vs -2.2%: P=0.003), despite similar baseline ambulatory BP (132/81 mm Hg) and BP reduction (6.5 and 4.6%: P=0.19). F-R_min remained unchanged (6.5 vs -2.0%: P=0.30), while C-R_min decreased by 22 and 24% (P=0.80) and CFR increased by 23 and 17% (P=0.16). Thus, intensified vasodilating therapy improved SVRI more in patients with high SVRI than in those with low SVRI. Regardless of SVRI status, the treatment improved cardiac but not forearm dilatation capacity. The substantial improvement of the hypertensive cardiac microvascular dysfunction was not related to the reduction in SVRI.

Prognostic value of calcium score and coronary flow velocity reserve in asymptomatic diabetic patients

BACKGROUND

The risk stratification of patients with diabetes mellitus (DM) is a major objective for the clinicians, and it can be achieved by coronary flow velocity reserve (CFVR) or with coronary artery calcium score (CS). CS evaluates underlying coronary atherosclerotic plaque burden and CFVR estimates both presence of coronary artery stenosis and microvascular function. Consequently, CFVR may provide unique risk information beyond the extent of coronary atherosclerosis.

AIM

Our aim is to assess joint prognostic value of CFVR and CS in asymptomatic DM patients.

MATERIALS AND METHODS

We prospectively included 200 asymptomatic patients (45,5 % male, mean age 57,35 ± 11,25), out of which, there were 101 asymptomatic patients with DM and 99 asymptomatic patients without DM, but with one or more conventionally risk factors for coronary artery disease. We analyzed clinical, biochemical, metabolic, inflammatory parameters, CS by Agatston method, transthoracic Doppler echocardiography CFVR of left anterior descending artery and echocardiographic parameters.

RESULTS

Total CS and CS LAD were significantly higher, while mean CFVR was lower in diabetics compared to the nondiabetics. During 1 year follow-up, 24 patients experienced cardio-vascular events (one cardiovascular death, two strokes, three myocardial infarctions, nine new onsets of unstable angina and nine myocardial revascularizations): 19 patients with DM and five non DM patients, (p = 0,003). Overall event free survival was significantly higher in non DM group, compared to the DM group (94,9 % vs. 81,2 %, p = 0,002 respectively), while the patients with CS ≥200 and CFVR <2 had the worst outcome during 1 year follow up in the whole study population as well as in the DM group. At multivariable analysis CFVR on LAD (HR 12.918, 95 % CI 3.865-43.177, p < 0.001) and total CS (HR 13.393, 95 % CI 1.675-107.119, p = 0.014) were independent prognostic predictors of adverse events in DM group of patients.

CONCLUSION

Both CS and CFVR provide independent and complementary prognostic information in asymptomatic DM patients. When two parameters are analyzed together, the risk stratification ability improves, even when DM patients are analyzed together with non DM patients. As a result, DM patients with CS ≥200 and CFVR <2 had the worst outcome. Consequently, the use of two tests identified subset of patients who can derive the most benefit from the intensive prevention measures.

Insulin resistance and acute glucose changes determine arterial elastic properties and coronary flow reserve in dysglycaemic and first-degree relatives of diabetic patients

BACKGROUND

Insulin resistance is linked to endothelial dysfunction. We investigated whether first-degree relatives of type-2 diabetes patients (FDR) present differences in vascular function at baseline and during postprandial hyperglycemia compared to dysglycaemic or normoglycaemic subjects.

METHODS

We studied 40 FDR with normal oral glucose test (OGTT), 40 subjects with abnormal OGTT (dysglycaemic) and 20 subjects with normal OGTT without parental history of diabetes (normoglycaemic) with similar clinical characteristics. Glucose, insulin, pulse wave velocity (PWV), central systolic blood pressure (cSBP) and augmentation index (AI) were measured at 0, 30, 60, 90 and 120min during OGTT. Coronary flow reserve (CFR) was assessed using Doppler echocardiography at 0 and 120min after OGTT. Insulin sensitivity was evaluated using Matsuda and insulin sensitivity index (ISI).

RESULTS

FDR and dysglycaemics had higher fasting insulin, reduced ISI, Matsuda index as well as reduced CFR (2.54 ± 0.5 vs. 2.45 ± 0.3 vs. 2.74 ± 0.5), increased PWV, (8.9 ± 1.1 vs. 10.3 ± 2.4vs. 8.0 ± 1.5 m/sec), AI (23.8 ± 13.6 vs. 26.5 ± 14.4vs.17.7  ±  14%) and cSBP than normoglycaemics (p < 0.05 for all comparisons). During OGTT, AI was similarly reduced in both normoglycaemic and FDR (p < 0.05) at peak insulin levels (60 min) though FDR had 2-fold higher insulin than normoglycaemics. AI was increased in dysglycaemics after peak glucose levels, at 120 min (p < 0.05). CFR was reduced by 10% and 15% at 120min in FDR and dysglycaemic respectively, while remained unchanged in normoglycaemics (p < 0.05). The percent reduction of CFR was related with the percent increase of glucose levels, ISI and Matsuda index(p < 0.05).

CONCLUSION

First-degree relatives and dysglycaemic patients have impaired arterial and coronary microcirculatory function. Insulin resistance determines acute vascular responses during postprandial hyperglycemia. CLINICALTRIALS.

GOV IDENTIFIER

NCT02244736.

[18F]fluorodeoxyglucose uptake in atherosclerotic plaques is associated with reduced coronary flow reserve in mice

OBJECTIVES

Coronary microvascular dysfunction, observed as impaired coronary vasodilator capacity, is an early manifestation of coronary artery disease. Inflammation plays an important role in different stages of atherogenesis. To study the role of vessel wall inflammation in the development of coronary dysfunction, we compared [(18)F]fluorodeoxyglucose (FDG) uptake in the aorta and coronary flow reserve (CFR) in atherosclerotic mice.

METHODS

We studied healthy young C57BL/6 mice fed a normal diet (n = 7) as well as hypercholesterolemic low-density lipoprotein receptor-disrupted/apolipoprotein B100-expressing (LDLR(-/-)ApoB(100/100)) mice (n = 15) and hypercholesterolemic and diabetic LDLR(-/-)ApoB(100/100)insulinlike growth factor II-overexpressing mice (n = 14) fed a western-type diet, aged 4 to 6 months. Doppler sonography was used to measure CFR as the ratio of coronary flow velocity during isoflurane-induced hyperemia and at rest. Uptake of [(18)F]FDG into the aorta was measured by autoradiography of tissue sections.

RESULTS

Histologic sections showed extensive atherosclerosis in the aorta, but coronary arteries were not obstructed. Both hyperemic coronary flow velocity and CFR were reduced (P < .05) in hypercholesterolemic mice with and without diabetes in comparison to healthy young C57BL/6 controls. Among hypercholesterolemic mice, both hyperemic flow velocity and CFR inversely correlated with atherosclerotic plaque [(18)F]FDG uptake in the aorta (r = -0.73; P < .001; r = -0.63; P = .001, respectively). In a multivariate analysis, including animal weight, aortic plaque burden, plasma glucose, plasma cholesterol, and [(18)F]FDG uptake in atherosclerotic plaques, only [(18)F]FDG uptake remained an independent predictor of reduced CFR (β = 0.736; P = .001).

CONCLUSIONS

The inflammatory activity in atherosclerotic plaques of the aorta independently predicts reduced CFR in atherosclerotic mice without obstructive coronary artery disease. This finding suggests that atherosclerotic inflammation contributes to coronary dysfunction.

The association between aortic distensibility and coronary flow reserve in newly diagnosed diabetic patients

INTRODUCTION

Aortic distensibility (AD) is an important parameter affecting coronary hemodynamics. Coronary flow velocity reserve (CFVR) is a reliable marker of coronary endothelial function in diabetic patients. The aim of this study was to investigate the association between AD and CFVR in newly diagnosed diabetic patients.

METHOD

We studied 77 patients with newly diagnosed diabetes mellitus (DM) and 30 age- and sex-matched healthy control subjects. CFVR was calculated as the hyperemic to resting coronary diastolic velocities ratio by using transthoracic echocardiography. Pulse pressure (PP) and AD were calculated.

RESULTS

Fasting blood glucose, HbA1c and PP were significantly higher in patients with diabetes (P < 0.001, P < 0.001 and P = 0.009, respectively). Other clinical and demographical characteristics, laboratory findings and echocardiographic findings were similar in both groups (P > 0.05, for all). The measurement of CFVR and AD in patients with diabetes were significantly lower compared with the controls (P < 0.001 and P = 0.001, respectively). CFVR was significantly negatively correlated with age, body mass index, HbA1c, systolic blood pressure, and PP, while significantly positively correlated with AD (P < 0.05, for all). Multivariate regression analysis showed that only AD (β = 0.485, P < 0.0001) and HbA1c (β = -0.362, P < 0.0001) were independently associated with CFVR. The cutoff value of AD obtained by the receiver operator characteristic (ROC) curve analysis was 2.44 for the prediction of impaired CFVR.

CONCLUSION

Aortic distensibility and HbA1c were independently associated with CFVR. The decrease in AD may be used as a marker of impaired coronary microcirculation in asymptomatic diabetic patients.

Coronary flow reserve predicts cardiopulmonary fitness in patients with coronary artery disease independently of systolic and diastolic function

AIMS

Despite revascularization and optimal medical treatment, patients with coronary artery disease (CAD) have reduced exercise capacity. In the absence of coronary artery stenosis, coronary flow reserve (CFR) is a measure of coronary microvascular function, and a marker of future poor outcome in CAD patients. The aim of this study was to examine the relationship among CFR, systolic and diastolic function, peripheral vascular function, and cardiopulmonary fitness in CAD patients.

METHODS AND RESULTS

Forty patients with median left ventricular ejection fraction (LVEF) 49 (interquartile 46-55) with documented CAD without significant left anterior descending artery (LAD) stenosis underwent cardiorespiratory exercise test with measurement of VO2 peak, digital measurement of endothelial function and arterial stiffness, and an echocardiography with measurement of LVEF using the biplane Simpson model, mitral early (E) and late (A) inflow velocities, and tissue Doppler diastolic (e') and systolic (s') velocities. Peak coronary flow velocity (CFV) was measured in the LAD using pulse-wave Doppler. CFR was calculated as the ratio between peak CFV at rest and during vasodilator stress. Median CFR was 2.22 (1.90-2.62) and VO2 peak was 21.8 (17.6-25.5). VO2 peak correlated significantly with CFR (r = 0.57, P < 0.001), E/e' (r = -0.35, P = 0.04), and s' (r = 0.41, P = 0.01) and with LVEF (r = 0.35, P = 0.03). CFR remained independently associated with VO2 peak after adjustment for systolic and diastolic function.

CONCLUSIONS

Coronary flow reserve measured noninvasively predicts cardiopulmonary fitness independently of resting systolic and diastolic function in CAD patients, indicating that cardiac output during maximal exercise is dependent on the ability of the coronary circulation to adapt to the higher metabolic demands of the myocardium.

Coronary flow reserve as a link between diastolic and systolic function and exercise capacity in heart failure

AIMS

In heart failure, a reduced exercise capacity is the prevailing symptom and an important prognostic marker of future outcome. The purpose of the study was to assess the relation of coronary flow reserve (CFR) to diastolic and systolic function in heart failure and to determine which are the limiting factors for exercise capacity.

METHODS AND RESULTS

Forty-seven patients with left ventricular ejection fraction (LVEF) <35 [median LVEF 31 (inter-quartile range 26-34)] underwent cardiorespiratory exercise test with measurement of VO2 peak, a dual X-ray absorptiometry scan for body composition, and a full echocardiography with measurement of LVEF using the biplane Simpson model, mitral inflow velocities, and pulsed wave tissue Doppler. Peak coronary flow velocity (CFV) was measured in the LAD, using pulsed-wave Doppler. CFR was calculated as the ratio between peak CFV at rest and during 2 min of adenosine stress. Fat-free-mass-adjusted VO2 peak correlated significantly with CFR (r = 0.48, P = 0.002), E/e' (r = -0.35, P = 0.02), and s' (r = 0.45, P = 0.001) but not with LVEF (r = 0.23, P = 0.11). CFR correlated significantly with E/e' (r = -0.46, P = 0.003) and s' (r = 0.36, P = 0.02), but not with LVEF (r = 0.18, P = 0.26). When adjusting for CFR in a multivariable linear model, s' but not E/e' remained independently associated with VO2 peak.

CONCLUSION

In this group of heart failure patients, VO2 peak was correlated with CFR, E/e', and s' but not with traditional measures of systolic function. CFR remained associated with VO2 peak independently of diastolic and systolic function and is likely to be a limiting factor in functional capacity of heart failure patients.

Association between serum total antioxidant status and coronary microvascular functions in patients with SLE

Mortality from cardiovascular disease has been found to be increased in patients with systemic lupus erythematosus (SLE). Coronary flow reserve (CFR) measurement is used both to assess epicardial coronary arteries and to examine the integrity of coronary microvascular circulation. Oxidative stress, enhancing modification of plasma lipids, is also associated with atherosclerotic events in lupus patients. Impairment of CFR and TAS has been shown to be an early manifestation of coronary atherosclerosis. Forty patients with SLE and 33 healthy volunteers were included in this study. Echocardiographic examination included left ventricular myocardial velocity measurements and coronary flow reserve (CFR) measurement. Serum total antioxidant status levels (TAS) also were measured using TAS kit. Lateral myocardial early peak velocity (Em) and lateral Em/Am ratio did not differ between the groups, but lateral myocardial atrial peak velocity (Am) was significantly higher in SLE group than the control group. Baseline coronary diastolic peak flow velocity (DPFV) of left anterior descending was similar in both the groups. However, hyperemic DPFV and CFR (2.50 ± 0.42 vs. 3.09 ± 0.45, P < 0.0001) were significantly lower in the SLE group than in the control group. CFR significantly and inversely correlated with CRP and significantly correlated with TAS. Subclinical coronary microvascular dysfunction can occur in SLE patients without traditional cardiovascular risk factors, probably associated with underlying inflammation and impairment of TAS.

Insulin resistance and exercise tolerance in heart failure patients: linkage to coronary flow reserve and peripheral vascular function

Background

Insulin resistance has been linked to exercise intolerance in heart failure patients. The aim of this study was to assess the potential role of coronary flow reserve (CFR), endothelial function and arterial stiffness in explaining this linkage.

Methods

39 patients with LVEF < 35% (median LV ejection fraction (LVEF) 31 (interquartile range (IQ) 26–34), 23/39 of ischemic origin) underwent echocardiography with measurement of CFR. Peak coronary flow velocity (CFV) was measured in the LAD and coronary flow reserve was calculated as the ratio between CFV at rest and during a 2 minutes adenosine infusion. All patients performed a maximal symptom limited exercise test with measurement of peak oxygen uptake (VO₂peak), digital measurement of endothelial function and arterial stiffness (augmentation index), dual X-ray absorptiometry scan (DEXA) for body composition and insulin sensitivity by a 2 hr hyperinsulinemic (40 mU/min/m²) isoglycemic clamp.

Results

Fat free mass adjusted insulin sensitivity was significantly correlated to VO₂peak (r = 0.43, p = 0.007). Median CFR was 1.77 (IQ 1.26-2.42) and was correlated to insulin sensitivity (r 0.43, p = 0.008). CFR (r = 0.48, p = 0.002), and arterial stiffness (r = −0.35, p = 0.04) were correlated to VO₂peak whereas endothelial function and LVEF were not (all p > 0.15). In multivariable linear regression adjusting for age, CFR remained independently associated with VO2peak (standardized coefficient (SC) 1.98, p = 0.05) whereas insulin sensitivity (SC 1.75, p = 0.09) and arterial stiffness (SC −1.17, p = 0.29) were no longer associated with VO2peak.

Conclusions

The study confirms that insulin resistance is associated with exercise intolerance in heart failure patients and suggests that this is partly through reduced CFR. This is the first study to our knowledge that shows an association between CFR and exercise capacity in heart failure patients and links the relationship between insulin resistance and exercise capacity to CFR.

Association of abnormal coronary microcirculatory function with impaired response of longitudinal left ventricular function during adenosine stress echocardiography in untreated hypertensive patients

AIMS

Coronary microcirculation is disturbed in hypertensive patients. We investigated the association of coronary flow reserve (CFR) with the response of left ventricular (LV) function as assessed by tissue Doppler imaging (TDI) during adenosine stress echocardiography in never-treated hypertensive patients.

METHODS AND RESULTS

We studied 90 hypertensive patients and 30 control subjects, matched for age and sex, by adenosine stress echocardiography. We measured: (i) CFR, E and A Doppler, S', E', A' mitral annulus velocities with TDI, as well as the E'/A' ratio and the E/E' ratio before and during adenosine infusion (ii) the %changes of the measured indices between baseline and adenosine infusion. After adenosine infusion, there was an increase in S', E', and A' in all patients and controls (P < 0.05). Compared with controls and patients with CFR ≥ 2.5, patients with CFR <2.5 showed a smaller increase in S' (28.6 vs. 30.0 vs. 11.1%, F for interaction = 14.592) and E' (33.3 vs. 33.3 vs.1.5%, F = 28.927) as well as a decrease in E'/A' (9.2 vs. 6.4% vs. -20.0%, F = 5.128) and an increase in E/E' (-6.1 vs. -1.6 vs. 30.5%. F = 12.780) after adenosine infusion (P < 0.05 for all comparisons). CFR was independently related to %changes of TDI parameters (regression coefficient b = 0.576 for S'; b = 0.517 for E'; b = 0.473 for E'/A'; b = -0.520 for E/E', respectively, P < 0.001). By the receiver operating curve, a CFR <2.5 predicted the median changes of all measured TDI markers, with a sensitivity and specificity over 70% (AUC >75%, P < 0.05).

CONCLUSION

An abnormal response of the LV longitudinal function during adenosine stress echocardiography is related to impaired CFR in untreated hypertensive patients.

Disproportionally impaired microvascular structure in essential hypertension

BACKGROUND

Increased microvascular resistance and small artery remodelling are key abnormalities in the pathophysiology of essential hypertension. We investigated the relation between the impairment of coronary and forearm minimum vascular resistances (C-Rmin and F-Rmin) and the degree of hypertension.

METHOD

Seventy-five never-treated essential hypertension patients with 24-h systolic blood pressure (BP) at least 130 mmHg or diastolic BP at least 80 mmHg were assigned into grade 1 (office BP 140/90-159/99 mmHg) and grade 2 (office BP 160/100-179/109 mmHg) hypertension and compared to normotensive controls (n = 25). The patients were (48 years, 60% men) without cardiovascular disease. C-Rmin and coronary flow reserve (CFR) were derived from flow measurements in the left anterior descending artery using transthoracic echocardiography. F-Rmin was measured using venous occlusion plethysmography. Resting systemic vascular resistance index (SVRI) was measured with a gas rebreathing technique.

RESULTS

Compared to normotensive controls: 24-h mean BP was raised 14% in grade 1 essential hypertension and 28% in grade 2 essential hypertension, whereas F-Rmin and C-Rmin were elevated by 58 and 87% in grade 1 essential hypertension and 72 and 125% in grade 2 essential hypertension. C-Rmin and F-Rmin were thus both increased more than expected from the BP level. SVRI and left-ventricular mass were increased proportionally to the BP. CFR was decreased by approximately 30% in both essential hypertension groups.

CONCLUSION

The results demonstrate excessive microvascular structural abnormalities in hypertension suggesting microvascular alterations occur early and not just as an adaptation to the BP level. Thus the level of BP elevation does not give an accurate indication of the microvascular involvement and impairment in essential hypertension.

[Functional vascular alterations associated with aortic valve stenosis]

Degenerative changes, atherosclerotic process and calcification of valvular leaflets are mostly responsible for valvular aortic valve stenosis, but congenital bicuspid aortic valve and rheumatic fever in history are also known predisposing factors. Aortic valve stenosis is frequently associated with different functional vascular alterations. The aim of this review is to demonstrate these vascular alterations evaluated by non-invasive methods and underlying physiologic and pathophysiologic processes.

Assessment of coronary flow velocity reserve by transthoracic Doppler echocardiography before and after coronary artery bypass grafting

Little is known about the changes in the coronary flow velocity reserve (CFVR) of the left anterior descending artery (LAD) before and after coronary artery bypass grafting (CABG). The present study aimed to evaluate the feasibility of measuring the CFVR of the LAD using transthoracic Doppler echocardiography before and after CABG. We prospectively measured the CFVR before and after CABG in 56 patients. The flow velocity in the LAD was measured using transthoracic Doppler echocardiography both at rest and during intravenous infusion of adenosine. The CFVR was calculated as the ratio of hyperemic to the basal peak and mean diastolic flow velocities. Coronary angiography was also performed to assess graft patency after CABG in all patients. Furthermore, we compared the differences between the pre- and postoperative CFVR in patients with and without a diffusely diseased LAD (lesion length >2 cm). All grafts were angiographically patent. The postoperative peak and mean CFVR were significantly increased compared to the preoperative peak and mean CFVR (both peak and mean 2.7 ± 0.9 vs 1.5 ± 0.6, respectively; p<0.0001). The preoperative peak CFVR was significantly lower in patients with a diffusely diseased LAD than in those without a diffusely diseased LAD (1.3 ± 0.5 vs 1.6 ± 0.5, respectively; p=0.04). The postoperative peak CFVR of the 2 groups was almost identical (2.5 ± 0.6 vs 2.9 ± 1.0; p=0.07). In conclusion, assessment of the CFVR of the LAD using transthoracic Doppler echocardiography was useful after CABG for confirming graft patency.

Coronary vasoreactivity is not altered in young people with type 1 diabetes

BACKGROUND AND AIM

Abnormal coronary microvascular circulation has been demonstrated in diabetes and is associated with increased rate of cardiovascular events. Our objective was to evaluate coronary vasoreactivity in young people with type 1 diabetes with and without microvascular complications.

METHODS AND RESULTS

Twenty-five type 1 diabetic patients without microvascular complications (DC-), 23 with microvascular complications (DC+), and 18 control subjects (C) were studied. Coronary vasoreactivity was assessed by means of coronary flow reserve (CFR). Blood flow velocity in the left anterior descending coronary artery was measured at rest and after high-dose dipyridamole using transthoracic color-guided pulsed Doppler echocardiography. CFR was defined as the ratio of hyperaemic to resting diastolic peak flow velocities. The three groups had similar cardiac function parameters, and also systolic and diastolic blood pressure at rest, which remained unchanged during dipyridamole infusion. Resting coronary flow velocity was comparable in C, DC-, and DC+ (p=ns). Dipyridamole infusion produced a threefold increase in coronary diastolic peak velocity, which reached similar values in C (0.69±0.16 m/s), DC- (0.69±0.18 m/s), and DC+ (0.66±0.11 m/s). Mean CFR ratio was similar in C (3.33±0.66), DC- (3.30±0.51), and DC+ (3.24±0.60). At multiple linear regression analysis, no association was found between CFR and age, sex, HbA(1c), duration of diabetes, and complications.

CONCLUSION

Coronary vasodilatory function is preserved in young D patients, even those with early microvascular complications, suggesting that coronary vasoreactivity deteriorates at more advanced stages of microvascular complications and/or in the presence of other cardiovascular risk factors.

The relationship between retinal microvascular abnormalities and coronary heart disease: a review

Heart disease remains the leading cause of death in the United States despite decades of advancement in its diagnosis and treatment. Because of the limitations of traditional risk stratification for heart disease, evaluation of the retinal vasculature has been proposed as an easily and safely measured adjunct to commonly used screening methods. This article provides a comprehensive review of the literature concerning the relationships between retinal microvascular abnormalities and coronary heart disease. We outline details of the most recent large epidemiologic studies and discuss their potential implications for clinical practice. Finally, we propose a change to the current guidelines regarding the screening of "low-risk" women, a group that is often failed by traditional evaluation algorithms.

Long-term prognostic value of coronary flow reserve in patients without significant left anterior descending coronary artery stenosis: results from the SZEGED Study

A coronariaáramlási rezerv (CFR) a bal coronaria leszálló szárában (LAD) szignifikáns szűkület hiánya esetén a microvascularis (disz)funkció jellemzésére használható hemodinamikai index. Célkitűzés: Jelen tanulmány célja a LAD-ban mért CFR prognosztikus értékének tisztázása lenne, amennyiben a koronarográfia során a LAD-ban szignifikáns szűkület nem volt igazolható. Módszerek: A jelen tanulmányban 166 olyan beteg eredményeit elemeztük, akiknél a CFR-vizsgálatok idején elvégzett koronarográfia a LAD-ban szignifikáns szűkületet (>50%) nem mutatott ki. Valamennyi esetben transthoracalis és terheléses transoesophagealis echokardiográfia (CFR-mérés), valamint koronarográfia történt. Eredmények: A továbbkövetés átlagos ideje 93±34 hónap volt, sikeressége 75%-osnak bizonyult (124/166). A továbbkövetés időszaka alatt 27 beteg hunyt el, 16 beteg esetén hirtelen szívhalál, 3 esetben akut szívelégtelenség, 2 esetben stroke volt a halál oka, míg 6 beteg pulmonalis, illetve gastrointestinalis tumoros folyamat miatt halt meg. A ROC-analízis során a CFR ≥ 2,13-t találtuk a legnagyobb pontosságú cut-off (határ-) értéknek a túlélés előrejelzésében (szenzitivitás 67%, specificitás 60%, görbe alatti terület 62%, p = 0,046). A 2,13-nál alacsonyabb CFR-rel bíró betegekben a továbbkövetés során szignifikánsan több esemény történt, mint az annál nagyobb értékkel bíróknál (32% vs. 13%, p < 0,05). A multivariáns logisztikus regressziós modell során a CFR [hazard ratio (HR) 2,43, p = 0,04] és a bal kamrai végszisztolés térfogatérték [HR 1,49, p = 0,03] bizonyult a túlélés független prediktorának. Következtetések: Hosszú távú továbbkövetéses vizsgálataink alapján megállapíthatjuk, hogy a CFR a túlélés független prediktora a LAD szignifikáns szűkületét nem mutató betegekben.

Clinical value of echocardiographic assessment of coronary flow reserve after left anterior descending coronary artery stenting in an unselected population

BACKGROUND

Transthoracic Doppler echocardiography is a valuable tool to measure coronary flow reserve (CFR) and detect in-stent restenosis (ISR) after percutaneous coronary angioplasty in selected series of patients.

OBJECTIVES

To assess the usefulness of coronary flow reserve measured by echocardiography in detecting significant (> or =70%) ISR of the left anterior descending coronary artery in a large unselected population.

METHODS

Two hundred and twenty-three patients (age 61 +/- 10 years; 168 men) treated with left anterior descending stenting underwent CFR measurement by transthoracic Doppler echocardiography and venous adenosine infusion 24-72 h before control coronary angiography. Coronary-active drugs were continued, and patients with multiple risk factors and old anterior-apical myocardial infarction were included.

RESULTS

Significant ISR occurred in 56 patients (25%). Patients with ISR had higher basal coronary flow velocity (27 +/- 10 cm/s vs. 24 +/- 7 cm/s; P < 0.002) and lower CFR (1.5 +/- 0.5 vs. 2.7 +/- 0.6; P < 0.0001) than those without ISR. A linear relation was found between ISR and CFR (r = -0.73; P < 0.0001) and remained significant after adjustment for blood pressure and heart rate (r = -0.74; P < 0.0001). A CFR less than two identified significant ISR (sensitivity 88%, specificity 88%, area under the curve = 0.943; P < 0.001). In a multivariate model of CFR prediction, myocardial infarction and heart rate were slightly contributory (ss = -0.19, P < 0.01; ss = -0.16, P < 0.03, respectively), whereas ISR had a large influence (ss = -0.66; P < 0.0001). The inverse correlation between ISR and CFR persisted in patients with myocardial infarction (r = -0.64; P < 0.0001) and in those treated with beta-blockers (r = -0. 71; P < 0.0001).

CONCLUSION

Echocardiographic measurement of CFR detects significant left anterior descending ISR in unselected patients with multiple risk factors, old anterior-apical myocardial infarction, and taking beta-blockers.

Incremental value of arterial wave reflections in the determination of left ventricular diastolic dysfunction in untreated patients with essential hypertension

Systemic arterial stiffness is an indicator of cardiovascular disease and an independent marker of morbidity and cardiovascular mortality. We investigated the association of arterial wave reflections with left ventricular (LV) diastolic dysfunction and their incremental value to other determinants of LV diastolic dysfunction in patients with essential hypertension. In total 143 patients and 20 controls with similar atherosclerotic risk factors were examined by applanation tonometry of the radial artery (Sphygmocor) and echocardiography. Central augmentation index (CAI%) of reflected arterial waves as well as aortic strain (AoS) assessed by echocardiography were estimated. Doppler diastolic abnormalities were defined as proposed by the European Study Group on diastolic heart failure by measurement of E/A ratio (the ratio of the mitral inflow velocities), isovolumic relaxation time, deceleration time and flow propagation velocity. AoS and CAI were impaired in patients compared with controls (4.67 +/- 2.94 vs 6.06 +/- 4.91% and 145.8 +/- 22.7 vs. 135.7 +/- 20.3%, P < 0.01) as well as in patients with LV diastolic dysfunction compared to patients without, (5.52 +/- 4.29 vs. 10.73 +/- 5.77% and 139.5 +/- 21.7 vs. 124.5 +/- 17.0%, P < 0.05). The odds ratio (OR) of AoS and CAI for diastolic dysfunction was OR:0.918, 95% confidence interval (CI):0.837-0.99, P = 0.04 and OR:1.023, 95% CI: 1.023-1.040 P = 0.010, respectively. The addition of CAI to the multivariable model including age, LV mass index, AoS and mean arterial pressure increased the power of the model for determination of LV diastolic dysfunction (-2 log likelihood = 139.368, change of chi2 = 4.2, P-value for change=0.04). In untreated patients with newly diagnosed essential hypertension, wave reflections are independent and additive determinants of LV diastolic dysfunction.

Transient impairment of coronary flow reserve in tako-tsubo cardiomyopathy is related to left ventricular systolic parameters

AIMS

Recent studies suggest that coronary flow reserve (CFR) is transiently impaired in tako-tsubo cardiomyopathy (TTC). Mechanisms by which such impairment occurs are still unknown. To assess the relationship between CFR obtained by transthoracic Doppler echocardiography (TDE) and parameters of left ventricular (LV) performance in patients with TTC.

METHODS AND RESULTS

A total of 20 consecutive patients in sinus rhythm, with TTC (mean age 70+/-9 years, 19 women) underwent serial evaluation of TDE-CFR, in the distal part of the left anterior descending coronary artery (LAD), at the acute phase and after recovery using intravenous adenosine infusion (140 microg/kg/min over 2 min). CFR was calculated as hyperaemic to basal mean diastolic coronary flow velocity (CFV). Average of the septal and lateral mitral annulus early diastolic (Ea) and systolic (Sa) tissue velocity, early (E) and late (A) diastolic transmitral velocity, the ratio E/Ea, wall motion score (WMS, 16 segment model), LV end-systolic volume index (ESV/m(2)) and LV end-diastolic volume index (EDV/m(2), biplane-Simpson method) were serially measured by TDE. Basal CFV, LV mass index and haemodynamics parameters did not differ between acute phase and recovery, whereas hyperaemic CFV increased significantly after recovery (P<0.01) leading to a greater CFR (2.9+/-0.3 vs. 2.1+/-0.4, P<0.0001). At the acute phase, hyperaemic CFV was significantly correlated to WMS, ESV/m(2), but not to E/Ea, whereas at recovery, hyperaemic CFV was not correlated to LV parameters. The improvement of CFR was closely correlated to the decrease of ESV/m(2), of WMS, but not to diastolic parameters. No significant correlation was found between CFR and E/Ea or LV mass index at each stage.

CONCLUSION

There is a transient impairment of CFR at the acute phase of TTC, which is due to a reduced vasodilating capacity. This impairment is closely correlated to LV systolic parameters. Diastolic compressive forces to the coronary microcirculation do not appear to play a critical role.

Beta-blockers and coronary flow reserve: the importance of a vasodilatory action

Coronary flow reserve (CFR) is the maximal increase in coronary blood flow (CBF) above its resting level for a given perfusion pressure when coronary vasculature is maximally dilated. Normally, hyperaemic CBF reaches values at least 2- to 3-fold greater than resting CBF. Reduction of CFR is mainly due to epicardial coronary artery stenosis or to coronary microvascular dysfunction. CFR can be determined by several techniques that measure CBF itself (e.g. positron emission tomography) or CBF velocities (Doppler methods) from which coronary flow velocity reserve is calculated. Hyperaemic coronary vasodilation can be obtained by pharmacological agents (e.g. adenosine and dipyridamole), but also by the cold pressure test. Long-term antihypertensive treatment induces significant improvement of CFR, which is parallel to the regression of left ventricular (LV) hypertrophy. First- and second-generation beta-adrenergic receptor antagonists (beta-blockers) have shown contradictory influences on CFR. This can be explained by the interaction of the effects on CBF at rest, generally reduced by these drugs, and after hyperaemia, when minimal coronary resistance appears to be either increased or reduced. Third-generation beta-blockers (e.g. carvedilol and nebivolol), which have vasodilating capacity, improve hyperaemic CBF. This occurs as a result of a reduction in minimal resistance, which can be attributed to alpha-adrenergic blockade and/or to a nitric oxide-mediated effect. This improvement is clearly beneficial in patients with coronary artery disease and indicates an improved coronary microvascular function. Changes of CFR due to vasodilating beta-blockers improve microvascular angina pectoris or silent ischaemia in patients without epicardial artery stenosis, and are also helpful in predicting the response or the further improvement of LV function to treatment.

Cardiovascular prognostic value of vascular involvement in Behcet's disease

We measured carotid artery intima-media thickness (IMT), brachial artery flow mediated dilation (FMD), and coronary flow reserve (CFR) in 38 Behcet's disease (BD) patients without vascular involvement, 15 BD patients with vascular involvement, and 35 control subjects. BD patients with and without vascular involvement were similar regarding carotid IMT (0.52+/-0.14; 0.51+/-0.09; 0.46+/-0.09; P=0.051), and brachial FMD (16.3+/-6.8; 16.5+/-9.1). CFR values were significantly impaired in BD patients compared to the controls; however the BD patients with and without vascular involvement were similar regarding CFR (2.66+/-0.45; 2.62+/-0.48; 2.91+/-0.53, P=0.007 with and without vascular involvement and the controls, respectively). Endothelial and coronary microvascular functions are compromised in BD patients without vascular involvement as remarkably as that in patients with vascular involvement.

Non-invasive assessment of coronary flow and coronary flow reserve by transthoracic Doppler echocardiography: a magic tool for the real world

Transthoracic Doppler echocardiography, introduced in the echo-lab in recent last years, to measure coronary flow and coronary flow reserve, is a very attractive tool, totally non-invasive, and easily available at bedside. This review summarizes the actual possibilities of this tool, its multiple potential clinical applications and diagnostic insights, and its arising prognosis value, in coronary artery disease as in various settings affecting the coronary microcirculation.

Effects of levosimendan on coronary artery flow and cardiac performance in patients with advanced heart failure

BACKGROUND

Levosimendan has inotropic and vasodilatory effects. We investigated the effects of levosimendan on coronary flow and associated changes in neurohormonal activation and cardiac performance in patients with advanced heart failure.

METHODS

Forty-two patients with NYHA III-IV and a left ventricular ejection fraction (EF) 25+/-6%, were randomised to levosimendan 0.1 microg/kg/min (n=21) or placebo for 24 h. Before and 24 h after each treatment, we assessed: the maximal velocity (Vmax), time integral (VTI) and deceleration time (DT) of the diastolic coronary flow wave (CF) in LAD using transthoracic Doppler echocardiography, pulmonary artery systolic pressure by Doppler echocardiography, E/E' ratio using Doppler imaging of mitral inflow velocity, tissue Doppler imaging of the mitral annulus and B-type natriuretic peptide (BNP) levels.

RESULTS

By ANOVA, there was a greater increase in CF-Vmax (43+/-23 vs.25+/-8 cm/s), CF-DT (904+/-250 vs. 667+/-151 ms), and EF and a greater decrease in BNP, pulmonary artery systolic pressure and E/E? after levosimendan than after placebo (p<0.05). Compared to baseline, the percent changes in CF-VTI were related to the concomitant changes in EF, E/E?, and BNP after treatment with levosimendan (r=0.69, r=?0.51 and r=?0.80, p<0.05 respectively).

CONCLUSION

Treatment with levosimendan improves coronary flow and microcirculation in parallel with an improvement in cardiac performance and neurohormonal activation in patients with advanced heart failure.

Impaired coronary microvascular function in familial Mediterranean fever

BACKGROUND

Patients with inflammatory rheumatic diseases have an increased risk of developing atherosclerosis. However, the question of whether patients with familial Mediterranean fever (FMF) are at risk of atherosclerosis and related diseases remains controversial.

OBJECTIVE

We aimed to use transthoracic Doppler echocardiography to investigate coronary flow reserve (CFR) and left ventricular (LV) diastolic function in patients with FMF.

METHODS

CFR and LV diastolic function were studied in 33 patients with FMF (16 men, 17 women; mean age, 36.7+/-12.0 years) and 35 healthy volunteers (20 men, 15 women; mean age, 36.8+/-5.2 years). Coronary diastolic peak flow velocities (DPFV) were measured at baseline and after dipyridamole infusion. LV diastolic function was assessed by standard and tissue Doppler imaging.

RESULTS

CFR was significantly lower in the FMF group than in the control group (2.27+/-0.38 versus 3.02+/-0.50, P<0.0001). Significant between-group differences were found regarding LV diastolic function mitral E/A ratio, mitral E-wave deceleration time, and lateral A(m). Serum high sensitivity C-reactive protein (hsCRP) levels were significantly higher in the patients with FMF, and hsCRP values independently correlated with CFR.

CONCLUSIONS

Coronary microvascular function and LV diastolic function are impaired in patients with FMF. The severity of these impairments is correlated with hsCRP. Impaired CFR may be an early manifestation of cardiac involvement in patients with FMF.

The coronary flow reserve is transiently impaired in tako-tsubo cardiomyopathy: a prospective study using serial Doppler transthoracic echocardiography

The clinical features of tako-tsubo cardiomyopathy or transient left apical ballooning syndrome (LABS) have been clearly described, but the mechanisms are still unknown. Our objective was to prospectively assess coronary microcirculation at the acute phase of LABS and after functional recovery, using Doppler transthoracic echocardiography-coronary flow reserve (CFR). Twelve consecutive patients (11 women, mean age 68 +/- 10 years) satisfying the criteria for LABS underwent Doppler transthoracic echocardiography-CFR in the distal part of the left anterior descending coronary artery, using intravenous adenosine infusion (0.14 mg/kg/min over 2 minutes) at the acute phase and 25 +/- 3 days later. CFR was calculated as the ratio of hyperemic to basal mean diastolic flow velocity. Wall-motion score (WMS) was calculated using the 16-segment model during the same echocardiographic examination (normal WMS = 16). Doppler transthoracic echocardiography-CFR increased between the two examinations from 2.2 +/- 0.4 at the acute phase to 2.9 +/- 0.3 (P < .01), whereas WMS decreased (from 31 +/- 6 at the acute phase to 16.5 +/- 0.8, delta WMS = -14.6 +/- 6, P < .01). All patients exhibited an increase of CFR between the two tests (delta CFR = 0.73 +/- 0.39, range: 0.3-1.6). A significant correlation was observed between delta CFR and delta WMS (r = -0.89, P < .01). In conclusion, serial noninvasive CFR measurements performed in LABS suggested transient microcirculatory impairment during the acute phase of the syndrome. The wall-motion improvement parallel to the dynamic improvement of the microcirculation suggests a role of coronary microcirculatory damage in the pathogenesis of acute and transient wall-motion abnormalities in LABS.

Close relationship between sympathetic activation and coronary microvascular dysfunction during acute hyperglycemia in subjects with atherosclerotic risk factors

BACKGROUND

The effect of acute hyperglycemia (AHG) during the oral glucose tolerance test (OGTT) on coronary microvascular function was evaluated, as well as the associations among the changes in coronary microvascular function, oxidative stress, and sympathetic tone.

METHODS AND RESULTS

Transthoracic Doppler echocardiography and OGTT were performed in 24 subjects with atherosclerotic risk factors (61+/-9 years). The coronary flow velocity before and during the infusion of adenosine (CFV(hyp)), plasma levels of thiobarbituric acid-reactive substances (TBARS), and the low-frequency/high-frequency power (LF/HF) ratio yielded by power spectral analysis of heart rate variability were measured before and at 1 h during 75-g OGTT. AHG significantly decreased the CFV(hyp), and increased the TBARS and LF/HF. Multiple linear regression analysis revealed that the percent changes in the CFV(hyp) were significantly associated with the percent changes in the LF/HF ratio (beta=-0.43, p<0.05).

CONCLUSION

In subjects with atherosclerotic risk factors who may be considered likely to have atherosclerotic arterial damage, AHG seems to induce concomitant coronary microvascular dysfunction, increased oxidative stress, and sympathetic activation. Coronary microvascular dysfunction, therefore, appears to be closely related to sympathetic activation.

The independent prognostic value of contractile and coronary flow reserve determined by dipyridamole stress echocardiography in patients with idiopathic dilated cardiomyopathy

The aim of this study was to evaluate the prognostic value of Doppler echocardiographically derived coronary flow reserve (CFR) in assessing inotropic response in patients with idiopathic dilated cardiomyopathy (IDC). One hundred thirty-two patients with IDC (90 men; mean age 62 +/- 11 years) were evaluated by transthoracic dipyridamole (0.84 mg/kg in 10 minutes) stress echocardiography. All patients had ejection fractions <40% (mean 33 +/- 7%) and angiographically normal coronary arteries, with New York Heart Association class <or=III. CFR was assessed in the left anterior descending coronary artery by pulsed Doppler as the ratio of maximal peak vasodilation (dipyridamole) to rest diastolic flow velocity. Inotropic reserve was identified as rest-stress variation in wall motion score index >0.25. All patients were followed for a median of 24 months. Mean CFR was 2.0 +/- 0.5. On individual patient analysis, 48 patients had normal CFR (>2), and 84 had abnormal CFR. The mean wall motion score index at rest was 2.0 +/- 0.33 and decreased to 1.8 +/- 0.4 at peak dipyridamole dose (p <0.000). Forty-two patients (32%) had inotropic reserve. During follow-up, 19 patients died, and 34 showed worsening of New York Heart Association class. The worst outcomes were observed in those patients with abnormal CFR and no inotropic reserve with high-dose dipyridamole. In a Cox model, mitral insufficiency (hazard ratio [HR] 1.7, 95% confidence interval [CI] 1.1 to 2.8), New York Heart Association class (HR 2.0, 95% CI 1.1 to 3.7), abnormal CFR (HR 2.8, 95% CI 1.0 to 8.5), wall motion score index at rest (HR 3.5, 95% CI 1.3 to 9.8), and the absence of inotropic reserve with high-dose dipyridamole (HR 2.3, 95% CI 1.06 to 5.1) were independent predictors of survival. In conclusion, in patients with IDC, CFR is often impaired. Reduced CFR and the absence of an inotropic response during vasodilator stress are additive in predicting a worse prognosis.

Assessment of intermediate severity coronary lesions in the catheterization laboratory

The management of intermediate coronary lesions, defined by a diameter stenosis of 40% to 70%, continues to be a therapeutic dilemma for cardiologists. The 2-dimensional representation of the arterial lesion provided by angiography is limited in distinguishing intermediate lesions that require stenting from those that simply need appropriate medical therapy. In the era of drug-eluting stents, some might propose that stenting all intermediate coronary lesions is an appropriate solution. However, the possibility of procedural complications such as coronary dissection, no reflow phenomenon, in-stent restenosis, and stent thrombosis requires accurate stratification of patients with intermediate coronary lesions to appropriate therapy. Intravascular ultrasound (IVUS) and fractional flow reserve index (FFR) provide anatomic and functional information that can be used in the catheterization laboratory to designate patients to the most appropriate therapy. The purpose of this review is to discuss the critical information obtained from IVUS and FFR in guiding treatment of patients with intermediate coronary lesions. In addition, the importance of IVUS and FFR in the management of patients with serial stenosis, bifurcation lesions, left main disease, saphenous vein graft disease, and acute coronary syndrome will be discussed.

Patients with Behcet's disease carry a higher risk for microvascular involvement in active disease period

BACKGROUND

Behcet's disease (BD) is characterized with remissions and exacerbations. However, to date, there is no study to investigate a possible association of disease activity (active versus inactive disease period) with cardiovascular complications.

METHODS

Forty patients with BD were evaluated in both active and in inactive disease period. For the control group 45 healthy volunteers, age and sex matched, were registered. Subjects with at least a 15-day lesion-free period were regarded in inactive disease period, and subjects with any oral, skin, and/or genital lesion was regarded as in active disease period. In each subject coronary diastolic peak flow velocities (DPFV) were measured at baseline and after dipyridamole infusion (0.84 mg/kg over 6 minutes) using an Acuson Sequoia C256 echocardiography system. Coronary flow reserve (CFR) was defined as the ratio of hyperemic to baseline DPFV.

RESULTS

CFR values were significantly lower in BD patients compared to the controls (2.57+/-0.50 versus 2.87+/-0.53, P = 0.006). In active disease period, basal DPFV (24.6+/-7.5 versus 27.3+/-6.6, P = 0.019) was significantly higher than in the inactive disease period. In the active disease period hyperemic DPFV (61.7+/-14.9 versus 56.8+/-16.7, P = 0.015) values decreased significantly. Therefore, in the active disease period CFR significantly decreased from 2.57+/-0.50 to 2.09+/-0.46, P<0.001. The only independent predictor of CFR within the active disease period was the disease duration (beta = -0.384, P = 0.012).

CONCLUSION

Within the active disease period, coronary microvascular function is more prominently impaired in BD patients. Therefore, BD patients are possibly more vulnerable to cardiovascular manifestations when they are in an active disease period.

Ultrasonographic assessment of basal coronary flow as a screening tool to exclude significant left anterior descending coronary artery stenosis

OBJECTIVE

Coronary blood flow exhibits a biphasic pattern at rest with a higher diastolic and a smaller systolic component. In the present investigation, we evaluated whether a decreased diastolic to systolic velocity ratio of basal coronary flow may be useful in the identification of subjects with significant left anterior descending coronary artery (LAD) stenosis.

METHODS

One hundred and twenty-nine consecutive patients (62 with unstable angina, 25 with acute myocardial infarction and 42 with chronic coronary artery disease) were included in the study. Blood flow velocities were recorded in the mid-distal portion of the LAD using an ATL 5000 CV HDI ultrasound system. All patients underwent coronary angiography and were divided into two groups according to the absence (group 1) or the presence (group 2) of significant LAD stenosis (lumen narrowing > or = 70%). In 60 of the 129 patients, coronary flow reserve was evaluated non-invasively.

RESULTS

Adequate Doppler recordings in the LAD were obtained by transthoracic echocardiography in 113 patients. There were no differences between groups with regard to sex, cardiovascular risk factors, left ventricular mass and volumes, ejection fraction, whereas the diastolic to systolic velocity ratio of basal coronary flow was significantly lower in group 2 patients (1.41 +/- 4.7 vs. 2.08 +/- 0.64, P < 0.00001). The receiver operating characteristic curve showed that a diastolic to systolic velocity ratio < 1.6 had a sensitivity of 77%, a specificity of 91%, a positive predictive value of 77%, a negative predictive value of 97%, and a diagnostic accuracy of 84% for the presence of significant LAD stenosis. In 55/60 patients, results of basal coronary flow and coronary flow reserve were concordant. On multivariate logistic regression analysis, the diastolic to systolic velocity ratio was a strong independent predictor of LAD stenosis > or = 70% (odds ratio 4.90, 95% confidence interval 1.65-7.30).

CONCLUSIONS

The present findings suggest that assessment of basal coronary flow in the LAD may be useful to rule out the presence of significant stenosis.