Coronary flow reserve in stress-echo lab. From pathophysiologic toy to diagnostic tool

Risk factors for unsuccessful restoration of coronary flow reserve after coronary bypass surgery

OBJECTIVES

Coronary flow reserve (CFR) is a strong predictor of cardiovascular events and prognosis in patients with coronary artery disease. This study aimed to evaluate preoperative factors associated with the unsuccessful restoration of CFR after coronary artery bypass grafting (CABG).

METHODS

Included in this study were the 65 patients who presented with functionally significant left anterior descending artery (LAD) lesions confirmed by both fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR), and who underwent successful CABG at our hospital within the study period. After CABG, graft patency was confirmed by coronary computed tomography angiography, and CFR in the LAD artery was measured by echocardiography. We defined postoperative CFR <2.5 as impaired CFR, and CFR ≥2.5 as preserved CFR.

RESULTS

Of the 65 patients, 14 patients (22%) showed impaired CFR, while 51 patients had preserved CFR. Patients with impaired CFR had significantly higher HbA1c (6.7% vs. 6.0%, P < 0.01), greater use of insulin (43% vs. 4%, P < 0.01), longer lesion length (33 mm vs. 25 mm, P = 0.044), and lower iFR (0.69 vs 0.81, P = 0.01) than those with preserved CFR, although both groups had comparable FFR (0.65 vs 0.64, P = 0.46). In receiver operating characteristic curve analysis, iFR had a significantly larger area under the curve than FFR in terms of the prediction of impaired CFR (0.74 vs 0.42, P = 0.01).

CONCLUSIONS

Poorly-controlled preoperative diabetes, greater reliance on insulin, longer lesion length and lower iFR were associated with postoperative impaired CFR, suggesting the involvement of microvascular dysfunction.

Exercise Stress Echocardiography in Athletes: Applications, Methodology, and Challenges

This comprehensive review explores the role of exercise stress echocardiography (ESE) in assessing cardiovascular health in athletes. Athletes often exhibit cardiovascular adaptations because of rigorous physical training, making the differentiation between physiological changes and potential pathological conditions challenging. ESE is a crucial diagnostic tool, offering detailed insights into an athlete's cardiac function, reserve, and possible arrhythmias. This review highlights the methodology of ESE, emphasizing its significance in detecting exercise-induced anomalies and its application in distinguishing between athlete's heart and other cardiovascular diseases. Recent advancements, such as LV global longitudinal strain (GLS) and myocardial work (MW), are introduced as innovative tools for the early detection of latent cardiac dysfunctions. However, the use of ESE also subsumes limitations and possible pitfalls, particularly in interpretation and potential false results, as explained in this article.

Effects of Exercise On Coronary Flow Reserve And Biochemical Parameters in Patients With Type 2 Diabetes Mellitus

The most important mortality and morbidity causes in diabetic patients are coronary, peripheral and cerebral diseases. The aim of our study was to noninvasively determine dysfunction in epicardial coronary arteries and microvascular circulation with measurement of coronary flow reserve using transthoracic echocardiography in patients with type 2 diabetes despite absence of ischemic symptoms, and to demonstrate the amelioration in endothelial functions, glycemic control and insulin resistance along with increase in coronary flow reserve after 8 weeks of regular exercise. 40 patients diagnosed with type 2 diabetes in Istanbul Facuty of Medicine, Department of Diabetes, who were on follow-up for at least three years due to diabetes, without ischemic symptoms and 20 healthy subjects took part in study. Basal values before exercise of diabetic patients who were included in the exercise program were compared with basal values of diabetic patients who did not exercise regularly. To summarize, regular exercise and physical activity are highly important in diabetic patients for primary and secondary protection against cardiovascular incidents. Physical activity increases insulin sensitivity in diabetic patients, and has many positive effects on glucose metabolism. It is the important way to decrease obesity and visceral fat tissue. There is evidence pointing out that regular exercise can defer or even prevent initiation of diabetes.

Doppler Echocardiography Assessment of Coronary Microvascular Function in Patients With Angina and No Obstructive Coronary Artery Disease

Echocardiographic evaluation is an essential part of the diagnostic work-up in patients with known or suspected cardiovascular disease. Transthoracic Doppler echocardiography (TTDE) enables straightforward and reliable visualization of flow in the left anterior descending artery. In the absence of obstructive coronary artery disease, low TTDE-derived coronary flow velocity reserve (CFVR) is considered a marker of coronary microvascular dysfunction (CMD). TTDE CFVR is free from ionizing radiation and widely available, utilizing high-frequency transducers, pharmacologic vasodilator stress, and pulsed-wave Doppler quantification of diastolic peak flow velocities. European Society of Cardiology guidelines recommend TTDE CFVR evaluation only following preceding anatomic invasive or non-invasive coronary imaging excluding obstructive CAD. Accordingly, clinical use of TTDE CFVR is limited and CMD frequently goes undiagnosed. An evolving body of evidence underlines that low CFVR is an important and robust predictor of adverse prognosis and continuing symptoms in angina patients both with and without obstructive CAD. The majority of angina patients have no obstructive CAD, particularly among women. This has led to the suggestion that there may be a gender-specific female atherosclerotic phenotype with less epicardial obstruction, and a low CFVR signifying CMD instead. Nevertheless, available evidence indicates low CFVR is an equally important prognostic marker in both men and women. In this review, TTDE CFVR was evaluated regarding indication, practical and technical aspects, and interpretation of results. Association with symptoms and prognosis, comparison with alternative invasive and non-invasive imaging modalities, and possible interventions in angina patients with low CFVR were discussed, and key research questions were proposed.

Should we routinely assess coronary artery Doppler in daily echocardiography practice?

A lot of people with coronary artery disease do not have specific symptoms, and myocardial infarction or death are the first manifestation of the disease. New accurate, non-invasive and safe screening methods are required that can assess the prognosis of patients during routine examinations performed on millions of people. The aim of this review was to discuss the current literature regarding the utility of non-invasive ultrasound imaging of the coronary artery in assessing a patient's prognosis in daily practice. Assessment of coronary artery flow during common stress echocardiography or echocardiography can provide additive incremental prognostic information without the burden of radiation. Exercise or pharmacologic stress echocardiography tests combined with coronary flow velocity reserve assessment has advantages over stress tests based only on regional wall motion abnormalities. Scanning of main coronary arteries as an addition to routine echocardiography can reveal patients at high risk of adverse cardiac events in the near future.

Effects of Anti-Inflammatory Treatment and Surgical Intervention on Endothelial Glycocalyx, Peripheral and Coronary Microcirculatory Function and Myocardial Deformation in Inflammatory Bowel Disease Patients: A Two-Arms Two-Stage Clinical Trial

Sixty inflammatory bowel disease (IBD) patients (45 Crohn disease and 15 ulcerative colitis, 40 ± 13 years, 53% male) were examined at baseline and 4 months after intervention (surgical (35 patients) or anti-TNFa treatment (25 patients)). IBD severity, using Mayo score, Harvey–Bradshaw Index (HBI) and biomarkers, was correlated with cardiovascular markers. At baseline, the disease severity, the white blood cells (WBC) values and the reducing power (RP) were significantly correlated with the aortic pulse wave velocity (PWV) (r = 0.4, r = 0.44 and r = 0.48, p < 0.05) and the lateral mitral E’ velocity (r = 0.35, p < 0.05 and r = 0.3, p < 0.05). Four months after intervention, there was a reduction of WBC (1962.8/mm³ ± 0.425/mm³, p < 0.001), C-reactive protein (CRP) (8.1 mg/L ± 1.7 mg/L, p < 0.001), malondialdehyde (MDA) (0.81 nmol/mg ± 0.37, p < 0.05) and glycocalyx perfused boundary region (PBR 5-25) (0.24 μm ± 0.05 μm, p < 0.01). Moreover, the brachial flow mediated dilatation (FMD), the coronary flow reserve (CFR) and the left ventricle global longitudinal strain (LV GLS) were significantly improved for both groups (4.5% ± 0.9%, 0.55 ± 0.08, 1.4% ± 0.35%, p < 0.01), while a more significant improvement of PWV/GLS was noticed in the anti-TNFa group. IBD severity is associated with vascular endothelial, cardiac diastolic, and coronary microcirculatory dysfunction. The systemic inflammatory inhibition and the local surgical intervention lead to significant improvement in endothelial function, coronary microcirculation and myocardial deformation.

Echocardiographic assessment of coronary microvascular dysfunction: Basic concepts, technical aspects, and clinical settings

Coronary flow reserve is the capacity of the coronary circulation to augment the blood flow in response an increase in myocardial metabolic demands and has a powerful prognostic significance in different clinical situations. It might assess with invasive and noninvasive technique. Transthoracic echocardiography Doppler is an emerging diagnostic technique, noninvasive, highly feasible, safe for patient and physician, without radiation, and able to detect macrovascular and microvascular anomalies in the coronary circulation. This review aims to describe the benefit and limits of echocardiographic assessment of coronary flow reserve.

The use of tissue Doppler imaging in the assessment of diastolic dysfunction in children with chronic lung diseases

Background

Chronic lung diseases (CLD) in children such as bronchiectasis and interstitial lung disease represent a major public health problem with limited therapeutic options. These patients develop pulmonary hypertension (and core-pulmonale in severe cases) because of the recurrent hypoxia and chronic inflammation; which results in right heart enlargement and ventricular hypertrophy. The early identification and convenient treatment of diastolic dysfunction can prevent further complications of the disease including diastolic heart failure and death. We aim to demonstrate the usefulness of tissue Doppler imaging echocardiography (TDI) in the detection of subtle myocardial affection in interstitial lung disease and bronchiectasis as subgroups of (CLD) in children. We studied echocardiographic parameters of 40 pediatric patients with chronic lung disease using conventional M mode and tissue Doppler imaging and compared them with 40 healthy controls of matching age and sex distribution.

Results

Myocardial performance index (MPI) showed that 28 subjects had abnormal right ventricular (RV) MPI (10 with severe affection ≥ 0.6) and 21 subjects had abnormal LV MPI (11 severe affections ≥ 0.6). Thirty percent (30%) of the cases had affected lateral E/E' and 47.5% had affected septal E/E' when compared to controls. Grades of diastolic dysfunction were: 0, 1, 2, 3 in 18, 15, 6, and 1 patients, respectively. MPI LV and MPI RV showed statistically higher values in patients compared to controls (P < 0.001).

Conclusion

This study proved that TDI can accurately detect subtle myocardial dysfunction in pediatric CLD patients.

Sustainability and Versatility of the ABCDE Protocol for Stress Echocardiography

For the past 40 years, the methodology for stress echocardiography (SE) has remained basically unchanged. It is based on two-dimensional, black and white imaging, and is used to detect regional wall motion abnormalities (RWMA) in patients with known or suspected coronary artery disease (CAD). In the last five years much has changed and RWMA is not enough on its own to stratify patient risk and dictate therapy. Patients arriving at SE labs often have comorbidities and are undergoing full anti-ischemic therapy. The SE positivity rate based on RWMA fell from 70% in the eighties to 10% in the last decade. The understanding of CAD pathophysiology has shifted from a regional hydraulic disease to a systemic biologic disease. The conventional view of CAD encouraged the use of coronary anatomic imaging for diagnosis and the oculo-stenotic reflex for the deployment of therapy. This has led to a clinical oversimplification that ignores the lessons of pathophysiology and epidemiology, and in fact, CAD is not synonymous with ischemic heart disease. Patients with CAD may also have other vulnerabilities such as coronary plaque (step A of ABCDE-SE), alveolar-capillary membrane and pulmonary congestion (step B), preload and contractile reserve (step C), coronary microcirculation (step D) and cardiac autonomic balance (step E). The SE methodology based on two-dimensional echocardiography is now integrated with lung ultrasound (step B for B-lines), volumetric echocardiography (step C), color- and pulsed-wave Doppler (step D) and non-imaging electrocardiogram-based heart rate assessment (step E). In addition, qualitative assessment based on the naked eye has now become more quantitative, has been improved by contrast and based on cardiac strain and artificial intelligence. ABCDE-SE is now ready for large scale multicenter testing in the SE2030 study.

Impaired coronary microcirculation is associated with left ventricular diastolic dysfunction in end-stage chronic kidney disease patients

INTRODUCTION

Coronary vascular dysfunction, as assessed by coronary flow reserve (CFR) in the left anterior descending coronary artery, is found in various conditions including end-stage chronic kidney disease (CKD). Currently, we investigated the associations of CFR with echocardiographic indices of systolic and diastolic cardiac function and identified independent predictors of CFR in hemodialysis patients.

METHODS

End-stage CKD patients treated with hemodialysis (n = 29) without known cardiovascular disease were recruited from a Hemodialysis Unit in Northwestern Greece. A thorough echocardiographic evaluation including CFR measurement following dipyridamole infusion was performed in all participants. Arterial stiffness was assessed by measurement of carotid-femoral pulse wave velocity and aortic augmentation index.

RESULTS

The mean age of the patients was 63 years, and mean duration of hemodialysis was 2.9 years. CFR was 1.60 ± 0.37 while dipyridamole caused a significant increase in E'_sep , S_lat , E'_lat , and Stroke volume (P < .05 for all). Independent predictors of CFR were posterior wall thickness (B -0.408, P = .013) and dipyridamole-induced changes in Tei index (B -0.425, P = .007). A severely decreased CFR < 1.5 was observed in 52% of the patients. E/E' ratio (B 10.84, P = .014) was the single independent predictor of severely decreased CFR.

CONCLUSIONS

In end-stage CKD patients on hemodialysis without known cardiovascular disease, impaired coronary vascular function was prevalent and related to increased left ventricular wall thickness, increased filling pressures, and dipyridamole-induced deteriorated myocardial function independently of the presence of wall-motion abnormalities. Further studies are required to clarify the prognostic role of dipyridamole-induced cardiac changes in hemodialysis patients.

Drop-off in positivity rate of stress echocardiography based on regional wall motion abnormalities over the last three decades

Previous studies have suggested a decline in positivity of stress cardiac imaging based on regional wall motion abnormalities (RWMA). To assess the rate of RWMA positivity of stress echocardiography (SE) over 3 decades in the same primary care SE lab. We retrospectively assessed the rate of SE positivity in 7626 SE tests (dipyridamole in 5053, dobutamine in 2496, exercise in 77) in consecutive patients with known or suspected coronary artery disease and /or heart failure who performed SE in a primary care referral center from April 1991 to May 2018. Starting April 2005, SE based on RWMA was complemented by assessment of coronary flow velocity reserve (CFVR) of the left anterior descending coronary artery. Starting October 2016, we added left ventricular contractile reserve (LVCR). Starting October 2016, we also added B-lines by lung ultrasound. There was a progressive decline over time in the rate of SE positivity based on RWMA from 24% (1991-1999) to 10% (2000-2009) down to 4% (2010-2018) (p < 0.0001). Positivity rate was 29% with CFVR, 16% with LVCR, and 12% with B-lines. Over three decades, we observed a dramatic decline in SE positivity rate based on classical RWMA. In the last decade, the positivity rate rose sharply thanks to the stepwise introduction of CFVR, LVCR and B-lines as additional positivity criteria in integrated quadruple SE.

The new clinical standard of integrated quadruple stress echocardiography with ABCD protocol

BACKGROUND

The detection of regional wall motion abnormalities is the cornerstone of stress echocardiography. Today, stress echo shows increasing trends of utilization due to growing concerns for radiation risk, higher cost and stronger environmental impact of competing techniques. However, it has also limitations: underused ability to identify factors of clinical vulnerability outside coronary artery stenosis; operator-dependence; low positivity rate in contemporary populations; intermediate risk associated with a negative test; limited value of wall motion beyond coronary artery disease. Nevertheless, stress echo has potential to adapt to a changing environment and overcome its current limitations.

INTEGRATED-QUADRUPLE STRESS-ECHO

Four parameters now converge conceptually, logistically, and methodologically in the Integrated Quadruple (IQ)-stress echo. They are: 1- regional wall motion abnormalities; 2-B-lines measured by lung ultrasound; 3-left ventricular contractile reserve assessed as the stress/rest ratio of force (systolic arterial pressure by cuff sphygmomanometer/end-systolic volume from 2D); 4- coronary flow velocity reserve on left anterior descending coronary artery (with color-Doppler guided pulsed wave Doppler). IQ-Stress echo allows a synoptic functional assessment of epicardial coronary artery stenosis (wall motion), lung water (B-lines), myocardial function (left ventricular contractile reserve) and coronary small vessels (coronary flow velocity reserve in mid or distal left anterior descending artery). In "ABCD" protocol, A stands for Asynergy (ischemic vs non-ischemic heart); B for B-lines (wet vs dry lung); C for Contractile reserve (weak vs strong heart); D for Doppler flowmetry (warm vs cold heart, since the hyperemic blood flow increases the local temperature of the myocardium). From the technical (acquisition/analysis) viewpoint and required training, B-lines are the kindergarten, left ventricular contractile reserve the primary (for acquisition) and secondary (for analysis) school, wall motion the university, and coronary flow velocity reserve the PhD program of stress echo.

CONCLUSION

Stress echo is changing. As an old landline telephone with only one function, yesterday stress echo used one sign (regional wall motion abnormalities) for one patient with coronary artery disease. As a versatile smart-phone with multiple applications, stress echo today uses many signs for different pathophysiological and clinical targets. Large scale effectiveness studies are now in progress in the Stress Echo2020 project with the omnivorous "ABCD" protocol.

Integrated quadruple stress echocardiography

Stress echocardiography (SE) is an established diagnostic technique. For 40 years, the cornerstone of the technique has been the detection of regional wall motion abnormalities (RWMA), due to the underlying physiologically-relevant epicardial coronary artery stenosis. In the last decade, three new parameters (more objective than RWMA) have shown the potential to integrate and complement RWMA: 1) B-lines, also known as ultrasound lung comets, as a marker of extravascular lung water, measured using lung ultrasound with the 4-site simplified scan symmetrically of the antero-lateral thorax on the third intercostal space, from mid-axillary to anterior axillary and mid-clavicular line; 2) left ventricular contractile reserve (LVCR), assessed as the peak stress/rest ratio of left ventricular force, also known as elastance (systolic arterial pressure by cuff sphygmomanometer/end-systolic volume from 2D echocardiography); 3) coronary flow velocity reserve (CFVR) on left anterior descending coronary artery, calculated as peak stress/rest ratio of diastolic peak flow velocity assessed using pulsed-wave Doppler. The 4 parameters (RWMA, B-lines, LVCR and CFVR) now converge conceptually, logistically, and methodologically in the Integrated Quadruple (IQ)-SE. IQ-SE optimizes the versatility of SE to include in a one-stop shop the core "ABCD" (asynergy+B-lines+contractile reserve+Doppler flowmetry) protocol. It allows a synoptic assessment of parameters mirroring the epicardial artery stenosis (RWMA), interstitial lung water (B-lines), myocardial function (LVCR) and small coronary vessels (CFVR). Each variable has a clear clinical correlate, different and complementary to all others: RWMA identify an ischemic vs. non-ischemic heart; B-lines a wet vs. dry lung; LVCR a strong vs. weak heart; CFVR a warm vs. cold heart. IQ-SE is highly feasible, with minimal increase in the imaging and analysis time, and obvious diagnostic and prognostic impact also beyond coronary artery disease - especially in heart failure. Large scale effectiveness studies with IQ-SE are now under way with the Stress Echo 2020 Study, and will provide the necessary evidence base prior to large scale acceptance of the technique.

Non-invasive coronary wave intensity analysis

Wave intensity analysis is calculated from simultaneously acquired measures of pressure and flow. Its mathematical computation produces a profile that provides quantitative information on the energy exchange driving blood flow acceleration and deceleration. Within the coronary circulation it has proven most useful in describing the wave that originates from the myocardium and that is responsible for driving the majority of coronary flow, labelled the backward decompression wave. Whilst this wave has demonstrated valuable insights into the pathogenic processes of a number of disease states, its measurement is hampered by its invasive necessity. However, recent work has used transthoracic echocardiography and an established measures of central aortic pressure to produce coronary flow velocity and pressure waveforms respectively. This has allowed a non-invasive measure of coronary wave intensity analysis, and in particular the backward decompression wave, to be calculated. It is anticipated that this will allow this tool to become more applicable and widespread, ultimately moving it from the research to the clinical domain.

Association Between Elevated Pulse Pressure and High Resting Coronary Blood Flow Velocity in Patients With Angiographically Normal Epicardial Coronary Arteries

BACKGROUND

The aim of our study was to evaluate the relationship of pulse pressure (PP), a raw index of arterial stiffness, with noninvasively determined coronary flow reserve (CFR) and its components, in patients with angiographically normal epicardial coronary arteries.

METHODS AND RESULTS

The study population included 398 patients without angiographic evidence of coronary stenosis, who underwent high-dose dipyridamole stress echocardiography with transthoracic-derived CFR evaluation on the left anterior descending artery. CFR was calculated as the ratio between high-dose dipyridamole and resting coronary diastolic peak velocities. Patients were divided into 2 groups: the first group included the first and second PP tertiles (n=298, PP ≤60 mm Hg) and the second group included the highest PP tertile (n=100, PP >60 mm Hg). Mean blood pressure, systolic blood pressure (both P<0.0001), age (P<0.002), and left ventricular mass index (P=0.013) were higher in the highest PP tertile, which also showed higher resting coronary flow velocity (31.6±9.6 cm/s versus 27.7±6.4 cm/s, P<0.0001) and marginally lower CFR (2.5±0.6 versus 2.6±0.6, P=0.044). Hyperemic coronary flow velocity did not differ between the 2 groups. By separate multiple linear regression analyses, after adjusting for sex, age, the highest systolic blood pressure tertile (≥140 mm Hg), left ventricular mass index, and cardiovascular risk factors, the highest PP tertile was associated with resting coronary flow velocity (P=0.003) and only marginally with hyperemic coronary flow velocity (P<0.02), whereas its association with CFR was not significant.

CONCLUSIONS

In patients without epicardial coronary artery stenosis, the highest PP tertile is associated with an increased coronary flow velocity at rest.

Prognostic Value of Coronary Flow Reserve Obtained on Dobutamine Stress Echocardiography and its Correlation with Target Heart Rate

Background:

Normal coronary flow velocity reserve (CFVR) (≥ 2) obtained in the left anterior descending coronary artery (LAD) from transthoracic echocardiography is associated with a good prognosis, but there is no study correlating CFVR with submaximal target heart rate (HR).

Objective:

To evaluate the prognostic value of CFVR obtained in the LAD of patients with preserved (>50%) left ventricular ejection fraction (LVEF) who completed a dobutamine stress echocardiography (DSE), considering target HR.

Methods:

Prospective study of patients with preserved LVEF and CFVR obtained in the LAD who completed DSE. In Group I (GI = 31), normal CFVR was obtained before achieving target HR, and, in Group II (GII = 28), after that. Group III (G III=24) reached target HR, but CFVR was abnormal. Death, acute coronary insufficiency, coronary intervention, coronary angiography without further intervention, and hospitalization were considered events.

Results:

In 28 ± 4 months, there were 18 (21.6%) events: 6% (2/31) in GI, 18% (5/28) in GII, and 46% (11/24) in GIII. There were 4 (4.8%) deaths, 6 (7.2%) coronary interventions and 8 (9.6%) coronary angiographies without further intervention. In event-free survival by regression analysis, GIII had more events than GI (p < 0.001) and GII (p < 0.045), with no difference between GI and GII (p = 0.160). After adjustment, the only difference was between GIII and GI (p = 0.012).

Conclusion:

In patients with preserved LVEF and who completed their DSE, normal CFVR obtained before achieving target HR was associated with better prognosis.

Fundamento:

A reserva de velocidade de fluxo coronariano (RVFC) adequada (≥ 2) obtida na artéria descendente anterior (ADA) através do ecocardiograma transtorácico associa-se a bom prognóstico, mas não há estudo correlacionando-a com a frequência cardíaca (FC) alvo (submáxima).

Objetivo:

Avaliar o valor prognóstico da RVFC obtida na ADA de pacientes com fração de ejeção do ventrículo esquerdo (FEVE) preservada (>50%) e ecocardiograma sob estresse com dobutamina (EED) concluído, considerando a FC alvo submáxima.

Métodos:

studo prospectivo de pacientes com FEVE preservada e RVFC obtida na ADA durante EED concluído. No Grupo I (GI=31), a RVFC adequada foi obtida antes de se atingir a FC alvo, e no Grupo II (G II=28), após. O Grupo III (G III=24) atingiu a FC alvo, mas a RVFC foi inadequada. Foram considerados eventos: óbito, insuficiência coronariana aguda, intervenção coronariana, coronariografia sem intervenção subsequente e internamento hospitalar.

Resultados:

Em 28 ± 4 meses, ocorreram 18 (21,6%) eventos, sendo 6% (2/31) no GI, 18% (5/28) no GII e 46% (11/24) no GIII. Foram 4 (4,8%) óbitos, 6 (7,2%) intervenções coronarianas e 8 (9,6%) coronariografias sem intervenção subsequente. Na sobrevida livre de eventos pela análise de regressão, GIII apresentou mais eventos do que GI (p < 0,001) ou GII (p < 0,045), não havendo diferença entre GI e GII (p = 0,160). Após o ajustamento, foi mantida a diferença apenas entre GIII e GI (p = 0,012).

Conclusão:

Em pacientes com FEVE preservada e EED concluído, a RVFC adequada obtida antes da FC alvo associou-se ao melhor prognóstico.

The use of echocardiography for the non-invasive evaluation of coronary artery disease

In the Western world, there are now millions of patients who undergo clinical procedures that evaluate coronary artery status each year. Methods span from direct imaging using angiography, computerized tomography, to nuclear magnetic imaging as well as to functional studies, such as positron emission tomography. These techniques have provided significant information to physicians, but there is still need for an improved accessibility. Angiographic methods are expensive and expose the patient to significant amounts of radiation, undesirable in younger patients. Among the novel technologies for coronary diagnostics, transthoracic echocardiography (TTE) of coronary arteries has provided an important alternative, particularly in everyday practice. Diagnostic arterial TTE can allow determination of the coronary wall lumen in at least three major coronary segments (left main [LM], left arterial descending [LAD] and right coronary artery [RCA]). Coronary wall thickness using the LAD has been preliminarily shown to be related to the risk of coronary events. Since it is well ascertained that coronary lesions found in any location indicate that at least 80% of the coronary tree is affected, this is very important clinical information. Evaluation of coronary status by TTE is a novel technology providing important information in ischemic syndromes, in cases of coronary malformations and other coronary diseases. KEY MESSAGES Coronary evaluation can be carried out by a variety of both invasive and non-invasive methods, many requiring radiation exposure or patient immobility. Transthoracic echocardiography (TTE) of the coronaries can, in particular, evaluate the coronary wall thickness, and this may be directly related to the coronary disease risk. TTE is a useful method for the monitoring of coronary flow reserve and can allow the detection of coronary malformations.

Feasibility of cardiovascular magnetic resonance derived coronary wave intensity analysis

BACKGROUND

Wave intensity analysis (WIA) of the coronary arteries allows description of the predominant mechanisms influencing coronary flow over the cardiac cycle. The data are traditionally derived from pressure and velocity changes measured invasively in the coronary artery. Cardiovascular magnetic resonance (CMR) allows measurement of coronary velocities using phase velocity mapping and derivation of central aortic pressure from aortic distension. We assessed the feasibility of WIA of the coronary arteries using CMR and compared this to invasive data.

METHODS

CMR scans were undertaken in a serial cohort of patients who had undergone invasive WIA. Velocity maps were acquired in the proximal left anterior descending and proximal right coronary artery using a retrospectively-gated breath-hold spiral phase velocity mapping sequence with high temporal resolution (19 ms). A breath-hold segmented gradient echo sequence was used to acquire through-plane cross sectional area changes in the proximal ascending aorta which were used as a surrogate of an aortic pressure waveform after calibration with brachial blood pressure measured with a sphygmomanometer. CMR-derived aortic pressures and CMR-measured velocities were used to derive wave intensity. The CMR-derived wave intensities were compared to invasive data in 12 coronary arteries (8 left, 4 right). Waves were presented as absolute values and as a % of total wave intensity. Intra-study reproducibility of invasive and non-invasive WIA was assessed using Bland-Altman analysis and the intraclass correlation coefficient (ICC).

RESULTS

The combination of the CMR-derived pressure and velocity data produced the expected pattern of forward and backward compression and expansion waves. The intra-study reproducibility of the CMR derived wave intensities as a % of the total wave intensity (mean ± standard deviation of differences) was 0.0 ± 6.8%, ICC = 0.91. Intra-study reproducibility for the corresponding invasive data was 0.0 ± 4.4%, ICC = 0.96. The invasive and CMR studies showed reasonable correlation (r = 0.73) with a mean difference of 0.0 ± 11.5%.

CONCLUSION

This proof of concept study demonstrated that CMR may be used to perform coronary WIA non-invasively with reasonable reproducibility compared to invasive WIA. The technique potentially allows WIA to be performed in a wider range of patients and pathologies than those who can be studied invasively.

Endomyocardial radial strain rate imaging during dobutamine stress echocardiography for the evaluation of contractile reserve in patients with dilated cardiomyopathy

PURPOSE

Myocardial contractile reserve is associated with clinical prognosis in patients with dilated cardiomyopathy (DCM). We assessed myocardial contractile reserve using tissue Doppler strain rate imaging with dobutamine stress echocardiography in DCM patients.

METHODS

Simultaneous echocardiography and left ventricular (LV) catheterization during dobutamine stress were performed in 20 patients with DCM, and echocardiography was performed in 31 control subjects. Dobutamine was infused at a starting dose of 5 μg/kg/min for 5 minutes and then at 10 μg/kg/min. Peak endomyocardial radial strain (ɛ) and systolic strain rate (SR_sys ) measured with echocardiography and the maximum first derivative of LV pressure (LV dP/dt_max ) derived from catheterization were used as indices of contractility. Their percentage change from baseline to the dose of 10 μg/kg/min was calculated.

RESULTS

The ɛ and SR_sys were significantly smaller in DCM patients than in controls. The LV dP/dt_max , ɛ, and SR_sys were significantly higher at the dose of 10 μg/kg/min than at baseline. The percentage change in SR_sys was significantly correlated with the percentage change in LV dP/dt_max .

CONCLUSIONS

Strain rate imaging during dobutamine stress in DCM might prove noninvasively informative for the evaluation of myocardial contractile reserve and provide insight into LV systolic dysfunction. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:555-560, 2016.

Epicardial adipose tissue in patients with end-stage renal disease on haemodialysis

PURPOSE OF REVIEW

Epicardial adipose tissue (EAT) is the visceral fat of the heart, sharing many of the pathophysiological properties of other visceral fat depots. EAT is a metabolically active paracrine and vasocrine organ that causes local cardiac inflammation and is strongly implicated in the pathogenesis of coronary atherosclerosis. This article highlights the findings of recent observational studies in patients on haemodialysis that link the quantity of EAT to increased rates of cardiovascular and coronary artery disease and review the proposed methods of pathogenesis and the possible role of EAT quantification to improve cardiovascular risk assessment.

RECENT FINDINGS

Increasing volumes of EAT in patients on haemodialysis correlate with increased inflammatory mediators, higher rates of cardiovascular disease and coronary artery calcification, independent of general adiposity. EAT is an independent predictor of mortality and a potentially modifiable target for therapeutic interventions.

SUMMARY

EAT is likely to play a central role in the pathogenesis of cardiovascular disease in patients on haemodialysis, adds incrementally to conventional cardiovascular risk stratification models and is a potential target for therapeutic intervention.

Association of arterial stiffness with coronary flow reserve in revascularized coronary artery disease patients

AIM: To investigate the association of arterial wave reflection with coronary flow reserve (CFR) in coronary artery disease (CAD) patients after successful revascularization.

METHODS: We assessed 70 patients with angiographically documented CAD who had undergone recent successful revascularization. We measured (1) reactive hyperemia index (RHI) using fingertip peripheral arterial tonometry (RH-PAT Endo-PAT); (2) carotid to femoral pulse wave velocity (PWVc-Complior); (3) augmentation index (AIx), the diastolic area (DAI%) and diastolic reflection area (DRA) of the central aortic pulse wave (Arteriograph); (4) CFR using Doppler echocardiography; and (5) blood levels of lipoprotein-phospholipase A₂ (Lp-PLA₂).

RESULTS: After adjustment for age, sex, blood pressure parameter, lipidemic, diabetic and smoking status, we found that coronary flow reserve was independently related to AIx (b = -0.38, r = 0.009), DAI (b = 0.36, P = 0.014), DRA (b = 0.39, P = 0.005) and RT (b = -0.29, P = 0.026). Additionally, patients with CFR < 2.5 had higher PWVc (11.6 ± 2.3 vs 10.2 ± 1.4 m/s, P = 0.019), SBPc (139.1 ± 17.8 vs 125.2 ± 19.1 mmHg, P = 0.026), AIx (38.2% ± 14.8% vs 29.4% ± 15.1%, P = 0.011) and lower RHI (1.26 ± 0.28 vs 1.50 ± 0.46, P = 0.012), DAI (44.3% ± 7.9% vs 53.9% ± 6.7%, P = 0.008), DRA (42.2 ± 9.6 vs 51.6 ± 11.4, P = 0.012) and LpPLA2 (268.1 ± 91.9 vs 199.5 ± 78.4 ng/mL, P = 0.002) compared with those with CFR ≥ 2.5. Elevated LpPLA2 was related with reduced CFR (r = -0.33, P = 0.001), RHI (r = -0.37, P < 0.001) and DRA (r = -0.35, P = 0.001) as well as increased PWVc (r = 0.34, P = 0.012) and AIx (r = 0.34, P = 0.001).

CONCLUSION: Abnormal arterial wave reflections are related with impaired coronary flow reserve despite successful revascularization in CAD patients. There is a common inflammatory link between impaired aortic wall properties, endothelial dysfunction and coronary flow impairment in CAD.

RV diastolic dysfunction: time to re-evaluate its importance in heart failure

Right ventricular (RV) diastolic dysfunction was first reported as an indicator for the assessment of ventricular dysfunction in heart failure a little over two decades ago. However, the underlying mechanisms and precise role of RV diastolic dysfunction in heart failure remain poorly described. Complexities in the structure and function of the RV make the detailed assessment of the contractile performance challenging when compared to its left ventricular (LV) counterpart. LV dysfunction is known to directly affect patient outcome in heart failure. As such, the focus has therefore been on LV function. Nevertheless, a strategy for the diagnosis and assessment of RV diastolic dysfunction has not been established. Here, we review the different causal mechanisms underlying RV diastolic dysfunction, summarising the current assessment techniques used in a clinical environment. Finally, we explore the role of load-independent indices of RV contractility, derived from the conductance technique, to fully interrogate the RV and expand our knowledge and understanding of RV diastolic dysfunction. Accurate assessment of RV contractility may yield further important prognostic information that will benefit patients with diastolic heart failure.

Estimation of coronary wave intensity analysis using noninvasive techniques and its application to exercise physiology

Wave intensity analysis (WIA) has found particular applicability in the coronary circulation where it can quantify traveling waves that accelerate and decelerate blood flow. The most important wave for the regulation of flow is the backward-traveling decompression wave (BDW). Coronary WIA has hitherto always been calculated from invasive measures of pressure and flow. However, recently it has become feasible to obtain estimates of these waveforms noninvasively. In this study we set out to assess the agreement between invasive and noninvasive coronary WIA at rest and measure the effect of exercise. Twenty-two patients (mean age 60) with unobstructed coronaries underwent invasive WIA in the left anterior descending artery (LAD). Immediately afterwards, noninvasive LAD flow and pressure were recorded and WIA calculated from pulsed-wave Doppler coronary flow velocity and central blood pressure waveforms measured using a cuff-based technique. Nine of these patients underwent noninvasive coronary WIA assessment during exercise. A pattern of six waves were observed in both modalities. The BDW was similar between invasive and noninvasive measures [peak: 14.9 ± 7.8 vs. -13.8 ± 7.1 × 10(4) W·m(-2)·s(-2), concordance correlation coefficient (CCC): 0.73, P < 0.01; cumulative: -64.4 ± 32.8 vs. -59.4 ± 34.2 × 10(2) W·m(-2)·s(-1), CCC: 0.66, P < 0.01], but smaller waves were underestimated noninvasively. Increased left ventricular mass correlated with a decreased noninvasive BDW fraction (r = -0.48, P = 0.02). Exercise increased the BDW: at maximum exercise peak BDW was -47.0 ± 29.5 × 10(4) W·m(-2)·s(-2) (P < 0.01 vs. rest) and cumulative BDW -19.2 ± 12.6 × 10(3) W·m(-2)·s(-1) (P < 0.01 vs. rest). The BDW can be measured noninvasively with acceptable reliably potentially simplifying assessments and increasing the applicability of coronary WIA.

Association of aortic stiffness and wave reflections with coronary flow reserve in women without obstructive coronary artery disease: An ancillary study from the National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE)

BACKGROUND

Increased aortic stiffness and reduced coronary flow reserve (CFR) independently predict adverse outcomes. But information about relationships between arterial properties and CFR in subjects without obstructive coronary artery disease (CAD) is limited.

METHODS

CFR was measured (Doppler flow wire and intracoronary adenosine) in 50 women (age 53 ± 11 years) with symptoms and signs of myocardial ischemia without obstructive CAD. Aortic pulse wave velocity (aPWV), a measure of aortic stiffness, was obtained via catheter pullback; radial artery pressure waves were measured by applanation tonometry and central aortic pressure synthesized.

RESULTS

Overall, CFR (mean 2.61 ± 0.47) was significantly correlated with aPWV (r = -0.51), pulse wave amplification (r = 0.45), augmented pressure (r = -0.48), augmentation index (AIx, r = -0.44), aortic systolic pressure (r = -0.49), left ventricular wasted energy (LVEw, r = -0.47) (all P < .001), systolic pressure time index (r = -0.37, P < .008), and rate pressure product (r = -0.29, P < .04). In the multiple regression model including aPWV, CFR was still significantly correlated with aPWV (P < .008) and aortic systolic pressure (P < .01). No other measures contributed significant additional information. Women with CFR ≤2.5 versus those with CFR >2.5 had greater aPWV (894 ± 117 vs 747 ± 93 cm/s, P < .001), augmented pressure (14 ± 4.9 vs 11 ± 4.1 mmHg, P < .008), AIx (32 ± 6.6 vs 27 ± 6.6%, P < .003), LVEw (30 ± 12 vs 21 ± 10 dyne-s/cm(2) × 10(2), P < .02) and reduced pulse pressure amplification (1.20 ± .07 vs 1.26 ± .10, P < .008) and pressure wave travel time (133 ± 7.3 vs 138 ± 6.9 milliseconds, P < .04).

CONCLUSIONS

Among symptomatic women without obstructive CAD, CFR was inversely related to aortic systolic pressure and indices of aortic stiffness. These changes in arterial properties increase left ventricular afterload requiring the ventricle to generate additional, but wasted, energy that increases indices of myocardial oxygen demand, reduces CFR and increases vulnerability to ischemia.

Evaluation of Microvascular Disease and Clinical Outcomes

Although coronary microcirculatory dysfunction occurs in numerous cardiac conditions and influences prognosis, it has been largely ignored in clinical practice due to the lack of adequate methods for its assessment. Microcirculatory dysfuntion may result from a variety of causes, including structural remodelling (arterioles or capillaries), dysregulation (paradoxical arteriolar vasoconstriction), hypersensitivity to vasoactive factors or adrenergic drive, and extravascular compression of collapsable elements. Thus, the selection of a method to interrogate coronary microcirculation should be based on the suspected cause of dysfunction. This article reviews such assessment tools and their prognostic information.

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.

Coronary Flow Velocity Reserve Assessment with Transthoracic Doppler Echocardiography

Coronary flow velocity reserve (CFVR) reflects global coronary atherosclerotic burden, endothelial function and state of the microvasculature. It could be measured using transthoracic Doppler echocardiography in a non-invasive, feasible, reliable and reproducible fashion, following a standardised protocol with different vasodilatory stimuli. CFVR measurement is a recommended complement to vasodilator stress echocardiography. It could serve as a diagnostic tool for coronary microvascular dysfunction and in the setting of epicardial coronary artery stenoses could help in identification and assessment of functional significance of coronary lesions and follow-up of patients after coronary interventions. CFVR has also a prognostic significance in different clinical situations.

Relationship between glycosylated hemoglobin A1c and coronary flow reserve in patients with Type 2 diabetes mellitus

Type 2 diabetes mellitus patients are at increased risk for macrovascular and microvascular complications. Both in vivo and in vitro studies of small arteries and arterioles of diabetic subjects demonstrate impaired endothelial function without anatomic lesions. Coronary flow reserve (CFR) is a surrogate marker of coronary microcirculatory endothelial function in diabetic patients without significant stenosis of the associated epicardial coronary artery. Glycosylated hemoglobin A1c is related to likelihood of occurrence of microvascular events. The objective of this article is to report on recent developments in multiple noninvasive techniques to assess CFR and their use in aiding the understanding of the relationship of CFR, glycemic control and cardiovascular outcomes.

Effects of Paclitaxel and Carboplatin combination on mechanical myocardial and microvascular functions: a transthoracic Doppler echocardiography and two-dimensional strain imaging study

AIM

Paclitaxel and carboplatin are frequently used chemotherapy drugs in the treatment of gynecologic malignancies. Little is known about their effects on left ventricular mechanical and coronary microvascular functions.

METHODS

Thirty consecutive patients were prospectively enrolled. Patients underwent transthoracic echocardiography (TTE) before and after chemotherapy, to evaluate left ventricular mechanical functions and coronary flow reserve (CFR). A comprehensive TTE, tissue Doppler and two-dimensional (2D) strain imaging were performed and coronary flow velocity was measured at baseline and after dipyridamole infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak flow velocities. Mitral annular velocities by tissue Doppler, peak strain, and systolic strain rate by velocity vector imaging (VVI) were measured. Baseline measurements were compared with healthy controls (n = 26).

RESULTS

No patient developed heart failure (HF) symptoms, no significant change occurred in left ventricular ejection fraction or cardiac output and no significant difference was observed in CFR after chemotherapy. Baseline mean longitudinal peak strain and systolic stain rate were similar between patients and controls: -17.5 ± 2.6% versus -17.6 ± 2.2% (P = NS) and -1.04 ± 0.14/sec versus -1.05 ± 0.12/sec (P = NS). Peak strain and systolic strain rate decreased significantly after chemotherapy (from -17.5 ± 2.6% to -16.2 ± 2.5%, P < 0.02; and from -1.05 ± 0.12/sec to -0.96 ± 0.11/sec, P = 0.01, respectively). However, mean longitudinal velocity did not change significantly.

CONCLUSION

Paclitaxel and carboplatin combination did not impair CFR; however, this chemotherapy combination could induce subtle impairment in myocardial mechanical function which can be detected by advanced deformation imaging techniques rather than by tissue Doppler imaging or conventional 2D and Doppler echocardiography.

Does mild renal failure affect coronary flow reserve after coronary artery bypass graft surgery?

INTRODUCTION

There are only a limited number of studies on the link between mild renal failure and coronary artery disease. The purpose of this study is to investigate the effects of mild renal failure on the distal vascular bed by measuring the coronary flow reserve (CFR) in transthoracic echocardiography after coronary artery bypass grafting (CABG).

METHODS

The study included 52 consecutive patients (12 women and 40 men) who had undergone uncomplicated CABG. The patients were divided into 2 groups. Group 1 included patients with a preoperative glomerular filtration rate (GFR) of 60-90 (mild renal failure), and group 2 included those with a GFR >90. The CFR measurements were carried out through a second harmonic transthoracic Doppler echocardiography.

RESULTS

The mean age was 60.08 ± 1.56 years in group 1 and 60.33 ± 1.19 in group 2. The mean preoperative CFR was 1.79 ± 0.06 in group 1 and 2.05 ± 0.09 in group 2. The mean postoperative CFR was 2.09 ± 0.08 in group 1 and 2.37 ± 0.06 in group 2. There was a statistically significant difference between the 2 groups as to preoperative creatinine clearance, preoperative estimated GFR, postoperative day 7 creatinine clearance, postoperative month 6 creatinine clearance, postoperative day 7 estimated GFR, postoperative month 6 estimated GFR, preoperative CFR, and postoperative CFR (P < .05). CFR was found to be unaffected by the choice of on-pump or off-pump technique (P = .907). After bypass surgery, there was a significant increase in the mean postoperative CFR, when compared with the mean preoperative CFR (P = .001).

CONCLUSION

In our study, we detected a decrease in CFR in patients with mild renal failure. We believe that in patients undergoing CABG for coronary artery disease, mild renal failure can produce adverse effects due to deterioration of the microvascular bed.

Coronary flow velocity reserve during dobutamine stress echocardiography

BACKGROUND

A coronary flow velocity reserve (CFVR)≥2 is adequate to infer a favorable prognosis or the absence of significant coronary artery disease.

OBJECTIVE

To identify parameters which are relevant to obtain CFVR (adequate or inadequate) in the left anterior descending coronary artery (LAD) during dobutamine stress echocardiography (DSE).

METHODS

100 patients referred for detection of myocardial ischemia by DSE were evaluated; they were instructed to discontinue the use of β-blockers 72 hours prior to the test. CFVR was calculated as a ratio of the diastolic peak velocity (cm/s) (DPV) on DSE (DPV-DSE) to baseline DPV at rest (DPV-Rest). In group I, CFVR was <2 and, in group II, CFVR was ≥2. The Fisher's exact test and Student's t test were used for the statistical analyses. P values<0.05 were considered statistically significant.

RESULTS

At rest, the time (in seconds) to obtain Doppler in LAD in groups I and II was not different (53±31 vs. 45±32; p=0.23). During DSE, LAD was recorded in 92 patients. Group I patients were older (65.9±9.3 vs. 61.2±10.8 years; p=0.04), had lower ejection fraction (61±10 vs. 66±6%; p=0.005), higher DPV-Rest (36.81±08 vs. 25.63±06 cm/s; p<0.0001) and lower CFVR (1.67±0.24 vs. 2.53±0.57; p<0.0001), but no difference was observed regarding DPVDSE (61.40±16 vs. 64.23±16 cm/s; p=0.42). β-blocker discontinuation was associated with a 4-fold higher chance of a CFVR<2 (OR= 4; 95% CI [1.171-13.63], p=0.027).

CONCLUSION

DPV-Rest was the main parameter to determine an adequate CFVR. β-blocker discontinuation was significantly associated with inadequate CFVR. The high feasibility and the time to record the LAD corroborate the use of this methodology.

Decreased serum selenium levels are correlated with diminished coronary flow reserve among hemodialysis patients

Cardiovascular diseases are the main reason of high mortality among hemodialysis patients. Decreased serum selenium levels may have a role in accelerated atherosclerosis in this patient group. The hypothesis of this study was to show a correlation between decreased serum selenium levels and coronary flow reserve as an indicator of endothelial dysfunction and atherosclerosis in HD patients. Seventy-one chronic hemodialysis patients and age 65 and sex-matched healthy controls were included in the study. Plasma selenium levels were measured by spectrophotometry, and coronary flow reserve was assessed by transthoracic Doppler echocardiography. Serum selenium levels (34.16 ± 6.15 ng/ml vs. 52.4 ± 5.51 ng/ml, P < 0.001) and coronary flow reserve values (1.73 ± 0.11 vs. 2.32 ± 0.28, P < 0.001) were significantly lower in hemodialysis patients compared with controls, respectively. There was a significant positive correlation between coronary flow reserve and serum levels of selenium (r = 0.676, P < 0.001). A linear regression analysis showed that serum levels of selenium were independently and positively correlated with coronary flow reserve (regression coefficient = 0.650, P < 0.05). This study was the first to show a positive and independent correlation between decreased selenium levels and diminished coronary flow reserve as an indicator of endothelial dysfunction and atherosclerosis in hemodialysis patients. Our data suggest that decreased serum selenium levels may facilitate the development of endothelial dysfunction and disruption of coronary flow reserve which occur before the development of overt atherosclerosis.

Transthoracic measurement of left coronary artery flow reserve improves the diagnostic value of routine dipyridamole-atropine stress echocardiogram

INTRODUCTION

We hypothesized that coronary flow reserve (CFR) in the left anterior descending artery (LAD) can be effectively measured during an accelerated dipyridamole-atropine stress echocardiography (DASE) protocol to improve the diagnostic performance of the test.

MATERIAL AND METHODS

In 64 patients with suspected or known coronary artery disease scheduled for coronary angiography DASE with concomitant CFR measurement in LAD was performed.

RESULTS

Coronary flow reserve measurement and calculation were feasible in 83% of patients. The positive predictive value of undetectable LAD flow was 81% for severe LAD disease. Measured values of CFR were in the range 1.3-4.1 (mean: 2.2 ±0.7). Significantly lower CFR was found in patients with LAD disease (1.97 ±0.62 vs. 2.55 ±0.57, p = 0.0015). The optimal cutoff for detecting ≥ 50% stenosis was CFR ≤ 2.1 (ROC AUC 0.776), corresponding with 68% sensitivity and 84% specificity. In patients with negative DASE results 67% of patients with LAD disease had abnormal CFR, whereas in patients with a positive DASE result 92% of patients with normal LAD had normal CFR. The DASE diagnostic accuracy for the detection of coronary artery disease (CAD) increased from 75% to 85% when CFR measurement was added to wall motion abnormality (WMA) analysis. No test with both abnormalities was false positive for the detection of coronary disease.

CONCLUSIONS

Incorporation of CFR measurement into WMA-based stress echocardiography is feasible even in an accelerated DASE protocol and can be translated into an approximate gain of 10% in overall test accuracy.

Neutrophil-to-lymphocyte ratio, insulin resistance, and endothelial dysfunction in patients with autosomal dominant polycystic kidney disease

Endothelial dysfunction (ED), insulin resistance (IR), and inflammation are risk factors for increased cardiovascular morbidity and mortality in autosomal dominant polycystic kidney disease (ADPKD). ADPKD patients may have increased carotid intima-media thickness (CIMT) and decreased coronary flow velocity reserve (CFVR). The neutrophil-to-lymphocyte ratio (NLR) was introduced as a marker to determine inflammation in various disorders. We aimed to investigate the relationship between NLR and IR, CFVR, CIMT, and the left ventricular mass index (LVMI) in normotensive ADPKD patients. Twentynine ADPKD patients (age 38.8 ± 10.2 years; 8 men and 21 women) and 19 healthy controls (age 33.8 ± 7.4 years; 8 men and 11 women) were included in this cross-sectional study. CFVR was calculated with echocardiography as the ratio of hyperemic to baseline diastolic peak coronary flow velocities. CIMT was measured in the distal common carotid artery by using a 10-MHz linear echocardiography probe. HOMA-IR was calculated NLR was calculated as the ratio of the neutrophil and lymphocyte counts. Age, sex, body mass index, and levels of glucose, creatinine, low-density lipoprotein (LDL)-cholesterol, high-density lipoprotein (HDL)-cholesterol, triglycerides, C-reactive protein (CRP), microalbuminuria, and creatinine clearance were similar between ADPKD patients and healthy subjects. NLR, CIMT, LVMI, and HOMA-IR were significantly higher and CFVR values were significantly lower in patients with ADPKD compared to that in healthy subjects. NLR showed positive correlation with CIMT, HOMA, insulin, glucose, and HDL cholesterol levels, while it was inversely correlated with CFVR and albumin level in all subjects. In patients with ADPKD, NLR showed positive correlation with HDL cholesterol level and inverse correlation with LVMI and albumin level. NLR that was found to be increased in patients with ADPKD may be a readily available marker of inflammation and ED.

Serum coenzyme Q10 levels are associated with coronary flow reserve in hemodialysis patients

Accelerated atherosclerosis is the major cause of mortality in patients on chronic hemodialysis (HD). The aim of this study was to evaluate the relation between coenzyme Q10 (CoQ10) levels and coronary flow reserve (CFR) in HD patients as an indicator of atherosclerosis. Seventy-one chronic HD patients and 65 age- and sex-matched healthy individuals were included in the study. Plasma CoQ10 levels were performed by high-performance liquid chromatography measurements. CFR was assessed by transthoracic Doppler echocardiography. Serum CoQ10 levels (1.36 ± 0.43 vs. 2.53 ± 0.55, P < 0.001) and CFR values (1.73 ± 0.11 vs. 2.32 ± 0.28, P < 0.001) were significantly lower in HD patients compared with controls. There was a significant positive correlation between CFR and serum levels of CoQ10 (r = 0.669, P < 0.001). A linear regression analysis showed that serum levels of CoQ10 were still significantly and positively correlated with CFR (regression coefficient = 0.235, P < 0.001). Our data have demonstrated that HD patients exhibit decreased plasma CoQ10 levels and CFR values. The study also showed for the first time that serum CoQ10 levels independently predict CFR in HD patients.

Relationship Between Brachial Artery Flow-Mediated Dilation, Carotid Artery Intima-Media Thickness and Coronary Flow Reserve in Patients With Coronary Artery Disease

Background

The aim of this study was to assess the relationship between brachial artery flow mediated dilation (FMD), carotid artery intima-media thickness (IMT) and coronary flow reserve (CFR) in patients with coronary artery disease (CAD).

Methods

Fifty patients with coronary artery disease, except left anterior descending artery (LAD), who showed no cardiac symptoms and 45 control subjects underwent assessment of brachial artery FMD, carotid artery intima-media thickness by high-resolution ultrasound. In addition, transthoracic second harmonic Doppler echocardiography was used to measure CFR.

Results

All of the parameters were found to be correlated with each other. CFR correlated with brachial artery FMD (r = 0.232, P < 0.05) and with carotid IMT (r = -0.403, P < 0.001). Carotid IMT correlated with brachial artery FMD (r = -0.211, P < 0.05).

Conclusion

Transthoracic CFR correlated with well-established noninvasive predictors of atherosclerosis and we suggest that it can be used as a surrogate for coronary atherosclerosis.

The impact of aging and atherosclerotic risk factors on transthoracic coronary flow reserve in subjects with normal coronary angiography

Age may affect coronary flow reserve (CFR) especially in subjects with atherosclerotic risk factors (ARFs). The aim of this prospective, multicenter, observational study was to determine the effects of aging on CFR in patients with normal epicardial coronary arteries and ARFs. Three-hundred-thirty-five subjects (mean age = 61 years) with at least one ARF but normal coronary angiography underwent high-dose dipyridamole stress-echo with Doppler evaluation of left anterior descending artery. CFR was calculated as the ratio between hyperemic and resting coronary diastolic peak velocities. Patients were divided in age quartiles. CFR was progressively reduced with aging (1st quartile: 3.01 ± 0.69, 4th quartile: 2.39 ± 0.49, p < 0.001). This was mainly due to a gradual increase of resting velocities (1st quartile = 26.3 ± 6.1 cm/s, 4th quartile = 30.2 ± 6.4 cm/s, p < 0.001) while the reduction of hyperemic velocities remained unaffected (1st quartile = 77.7 ± 18.9 cm/s, 4th quartile = 70.9 ± 18.4 cm/s, NS). When age quartiles and ARFs were entered into a regression model, third and fourth age quartile (p < 0.0005 and p < 0.0001 respectively), left ventricular mass index (p < 0.0001), diastolic blood pressure (p < 0.001), total cholesterol (p < 0.002), fasting blood glucose (p < 0.01) and male gender (p < 0.05) were independent determinants of CFR in the whole population. Aging reduces coronary flow reserve in patients with angiographically normal coronary arteries due to a gradual increase of resting coronary flow velocity. CFR is also affected by atherosclerotic risk factors and left ventricular hypertrophy.

[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.

Angiographically borderline left main coronary artery lesions: correlation of transthoracic doppler echocardiography and intravascular ultrasound: a pilot study

Background

the clinical decision making could be difficult in patients with borderline lesions (visually assessed stenosis severity of 30 to 50%) of the left main coronary artery (LM). The aim of the study was to evaluate the relationship between transthoracic Doppler (TTDE) peak diastolic flow velocity (PDV) and intravascular ultrasound (IVUS) measurements in the assessment of angiographically borderline LM lesions.

Methods

27 patients (mean age 64 ± 8 years, 21 males) with borderline LM stenosis referred for IVUS examination were included in the study. We performed standard IVUS with minimal lumen area (MLA) and plaque burden (PB) measurement and routine quantitative coronary angiography (QCA) with diameter stenosis (%DS) and area stenosis (%AS) assessment in all. During TTDE, resting PDV was measured in the LM.

Results

interpretable Doppler signal could be obtained in 24 patients (88% feasibility); therefore these patients entered the final analysis. MLA was 7.1 ± 2.7 mm². TTDE measured PDV correlated significantly with IVUS-derived MLA (r = -0.46, p < 0.05) and plaque burden (r = 0.51, p < 0.05). Using a velocity cut-off of 112 cm/sec TTDE showed a 92% sensitivity and 62% specificity to identify IVUS-significant (MLA < 6 mm²) LM stenosis.

Conclusion

In angiographically borderline LM disease, resting PDV from transthoracic echocardiography is increased in presence of increased plaque burden by IVUS. TTDE evaluation might be a useful adjunct to other invasive and non-invasive methods in the assessment of borderline LM lesions. Further, large scale studies are needed to establish the exact cut-off value of PDV for routine clinical application.