Measurement Of Coronary Flow Reserve Research Articles

Myocardial Perfusion Imaging for the Evaluation of Ischemic Heart Disease in Women

To review the value of myocardial blood flow and coronary flow reserve (CFR) measurements, as assessed by positron emission tomography (PET), in women with suspected ischemic heart disease. CFR is a noninvasive measure of coronary vasomotor function that integrates the hemodynamic effects of epicardial coronary stenosis, diffuse atherosclerosis, and microvascular dysfunction on myocardial tissue perfusion and has emerged as an imaging marker of cardiovascular risk, independently of the degree of obstructive coronary artery disease (CAD). Normal coronary arteries or nonobstructive CAD is a common finding in women with ischemia. Thus, assessment of risk based on a coronary stenosis approach may fail in women. PET is able to quantify absolute myocardial blood flow and CFR which may help to elucidate other mechanisms involved such as microvascular dysfunction and diffuse epicardial CAD, responsible for the disease in women.

Assessment of coronary flow reserve predicts long-term outcome of responders to cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) has been established as a treatment for patients with chronic heart failure (HF). We tested the hypothesis that assessment of coronary flow reserve (CFR) predicts the long-term outcome of CRT. The study consisted of 114 HF patients implanted with a CRT device for the treatment of advanced HF between April 2010 and April 2018. After excluding patients that withdrew from long-term follow-up and patients missing a baseline CFR measurement, we enrolled 53 eligible patients. CFR was determined non-invasively by transthoracic echocardiography. Based on the ROC curve for predicting the appearance of major adverse cerebral and cardiovascular events (MACCE), the level of preserved CFR was set at >1.35 in responders. Accurate follow-up information (mean 873 ± 498days) was obtained in 23 patients with a preserved CFR (16 females; mean age 71 ± 7.9years) and 11 patients with a depressed CFR (5 females; mean age, 73 ± 7.6years) in responders. Kaplan-Meier survival analysis demonstrated that the depressed CFR group had a higher prevalence of MACCE than the preserved CFR group (log rank, 9.83; p = 0.0021). Multivariate analysis revealed that depressed CFR was associated with MACCE (hazard ratio 4.88, 95% confidence interval 1.13-26.5, p = 0.0329). Our results suggest that the assessment of CFR predicts the outcome in responders to CRT. Preservation of coronary circulation flow might underlie one of the mechanisms for a better response to CRT in responders.

Influence of visual-functional mismatch on coronary flow profiles after percutaneous coronary intervention: a propensity score-matched analysis.

The aims of this study are to clarify whether discrepancies between angiographic and fractional flow reserve (FFR) measurements (visual-functional mismatch) influence coronary flow profiles after percutaneous coronary intervention. While current guidelines FFR-guided revascularization, clinical practice most commonly relies on angiographic evaluation, which may under- or over-estimate the functional relevance of the lesion. Our retrospective analysis involved 274 vessels from 264 patients with stable angina pectoris who underwent FFR, index of microvascular resistance, and coronary flow reserve (CFR) measurements before and after PCI. Visual-functional concordance and discordance (reverse mismatch) were defined as angiographic stenosis > 50% with FFR ≤ 0.80 and angiographic stenosis ≤ 50% with FFR ≤ 0.80, respectively. Propensity score-matched cohort included 132 lesions (66 lesions: concordant findings, 66 lesions: reverse mismatch). The change in coronary flow profiles after PCI was assessed in terms of FFR, CFR, index of microvascular resistance (IMR), and mean transit time (Tmn). Compared with concordant territories, reverse mismatch territories were associated with lower pre-PCI IMR, higher pre-PCI CFR, greater minimum lumen diameter and smaller reference diameter (all comparisons, P < 0.05). After propensity score matching, the prevalence and extent of coronary flow improvement after PCI, evaluated by CFR and Tmn, were both remained significantly greater in concordant territories (all comparisons, P < 0.05). The prevalence and extent of coronary flow improvement after PCI assessed by the physiologic indices was significantly greater in visual-functional concordant lesions, suggesting that these coronary physiologic changes were associated with discrepancy between angiographic measurements.

THE RELATIONSHIP BETWEEN CARDIAC MRI DERIVED STRAIN AT REST AND CORONARY FLOW RESERVE

Coronary flow reserve (CFR) measurements have been used to assess ischemic burden. We used cardiac MR (CMR) derived ventricular strain to explore the relationship between CFR and myocardial deformation. A total of 31 subjects with a clinically-indicated Rb-82 PET consented to the IRB approved

Identification of capillary rarefaction using intracoronary wave intensity analysis with resultant prognostic implications for cardiac allograft patients.

Techniques for identifying specific microcirculatory structural changes are desirable. As such, capillary rarefaction constitutes one of the earliest changes of cardiac allograft vasculopathy (CAV) in cardiac allograft recipients, but its identification with coronary flow reserve (CFR) or intracoronary resistance measurements is hampered because of non-selective interrogation of the capillary bed. We therefore investigated the potential of wave intensity analysis (WIA) to assess capillary rarefaction and thereby predict CAV. Fifty-two allograft patients with unobstructed coronary arteries and normal left ventricular (LV) function were assessed. Adequate aortic pressure and left anterior descending artery flow measurements at rest and with intracoronary adenosine were obtained in 46 of which 2 were lost to follow-up. In a subgroup of 15 patients, simultaneous RV biopsies were obtained and analysed for capillary density. Patients were followed up with 1-3 yearly screening angiography. A significant relationship with capillary density was noted with CFR (r = 0.52, P = 0.048) and the backward decompression wave (BDW) (r = -0.65, P < 0.01). Over a mean follow-up of 9.3 ± 5.2 years patients with a smaller BDW had an increased risk of developing angiographic CAV (hazard ratio 2.89, 95% CI 1.12-7.39; P = 0.03). Additionally, the index BDW was lower in those who went on to have a clinical CAV-events (P = 0.04) as well as more severe disease (P = 0.01). Within cardiac transplant patients, WIA is able to quantify the earliest histological changes of CAV and can predict clinical and angiographic outcomes. This proof-of-concept for WIA also lends weight to its use in the assessment of other disease processes in which capillary rarefaction is involved.

UTILITY OF NON-INVASIVE CORONARY FLOW PATTERN VERSUS FRACTIONAL FLOW PRESSURE DROP FOR LEFT ANTERIOR CORONARY ARTERY STENTING

Background and Aim: To assess the usefulness of coronary flow reserve as a guide in patient with left anterior descending coronary artery lesion during percutaneous coronary intervention in comparison with fractional flow reserve. Methods: The study included 80 patients with left anterior descending artery stenotic lesions, proved by coronary angiography, in the cardiac catheterization laboratory of the Faculty of Military Hospital, during the period from November 2012 to June 2014. All patients were subjected to all of the following: Complete history taking, full general and local examination, ECG analysis. All our patient were assessed by Doppler wire to measure pressure drop at LAD lesion and also by non-invasive coronary flow pattern utilizing transthoracic echo-Doppler study. Then we compare the results of both values on the basis of the improvement in left ventricular ejection fraction( by biplane Simpson rule) to find the cut point at which we can document that this LAD lesion deserve stenting . Results: FFR was negatively correlated with significant correlation with EF improvement with R value of -0.575 and P-value of 0.008,figure. Also there is strong inversed relation with lesion percent with R-value of-0.468 and P-value of 0.01. The correlation between FFR and improvement in wall motion score was significantly inversed with R-value of -0.519 and P-value of 0.03. Also there was strong correlation between FFR and CFR ,P-value was 0.00 and R-value was+0.436. CFR has strong reciprocal correlation with FFR (P-value was 0.00 and R-value was. inve+0.436. There is significant correlation of CFR with EF improvement with R value of -0.583and P-value of 0.002. Also there is significant correlation of CFR with lesion percent with R-value of -0.585and P-value of 0.001, figure. The correlation between CFR and wall motion score was significant with R-value of-0.393 and P-value of 0.03. The optimal cutoff values for coronary flow reserve of <1.75 was the best value for indication of stenting of an intermediate coronary lesion. A sensitivity of 92% and a specificity of 87%. On the other hand the best cut-of value of fractional flow reserve was <0.75 for indication of stenting for an intermediate coronary artery lesion with a sensitivity of 94% and specificity of 86%. Conclusions: The current study showed Coronary flow reserve measurements by TTE in the distal to mid LAD were feasible in most patients with an optimal cut-off value < 1.75 showed high accuracy to detect angiographically significant stenoses in the LAD. This is comparable to <0.75 as an optimal cut-off value of FFR to detect angiographically significant stenoses. CFR measurement utilizing TTE might be considered as a simple non-invasive tool for functional status of an intermediate coronary artery lesion for stenting. Key Words: LAD (left anterior descending artery ), coronary flow reserve, fractional flow reserve.

Optimal Diagnostics and Therapy for Microvascular Angina Pectoris

Patients with microvascular angina are characterized by angina pectoris with proof of myocardial ischemia in the absence of any relevant epicardial stenosis and without myocardial disease (type 1 coronary microvascular dysfunction according to Crea and Camici). Structural and functional alterations of the coronary microvessels (diameter < 500 µm) are the reason for this phenomenon. Frequently such alterations are associated with cardiovascular risk factors. Patients with angina pectoris without epicardial stenoses represent for 10 - 50 % of all patients undergoing coronary angiography depending on the clinical presentation. Diagnostic approaches include non-invasive (e. g. combination of coronary CT-angiography and positron emission tomography/echo Doppler-based coronary flow reserve measurements) as well as invasive procedures (coronary flow reserve measurements in response to adenosine, intracoronary acetylcholine testing). Pharmacological treatment of these patients is often challenging and should be based on the characterization of the underlying mechanisms. Moreover, strict risk factor control and individually titrated combinations of antianginal substances (e. g. beta blockers, calcium channel blockers, nitrates, ranolazine, ivabradine etc.) are recommended.

TCT-134 Impact of post-percutaneous coronary intervention fractional flow reserve measurement on procedural management and clinical outcomes: the REPEAT-FFR Study

TCT-134 Impact of post-percutaneous coronary intervention fractional flow reserve measurement on procedural management and clinical outcomes: the REPEAT-FFR Study

Clues to Discordance and Dissimilarity Between Coronary Stenosis and Lesion-Specific Ischemia

Traditional diagnostic accuracy statistics have defined discordance between a stenosis and preserved coronary blood flow as a false-positive finding. With expanded use of invasive and noninvasive fractional flow reserve (FFR), as well as positron emission tomography measures of coronary flow reserve, our knowledge base has grown substantially, providing greater insight into the underlying rationale for discordant findings. We now understand that the presence of an obstructive stenosis is but one parameter which may elicit reductions in blood flow and prompt ischemic symptoms. Vessel size, collateral flow, and the length of the diseased segment are a few of the factors influencing coronary blood flow.1 Thus, for any given patient with an obstructive stenosis, reductions in coronary blood flow may or may not be present. Throughout the prior reported series,2,3 limited evidence is available with regards to coronary stenosis severity and location, as well as clinical patient subgroups, where the disconnect between stenosis severity and lesion-specific ischemia with FFR may …

Usefulness of coronary flow reserve measured by transthoracic coronary Doppler ultrasound in the elderly.

The left anterior descending (LAD) coronary artery is the main vessel of human coronary circulation, and life-threatening consequences are seen when flow in this area is impaired.[1] Noninvasive measurement of coronary flow reserve (CFR), defined as the ratio of maximal to baseline coronary blood flow, has been repeatedly shown to be a feasible technique by ultrasound transthoracic Doppler (TTD) both in the LAD and, with some limitations, in the posterior descending (PD) coronary artery.[2]–[7] CFR by TTD offers two important pieces of information: information about patency and flow through the large epicardial coronary artery proximal to the site of CFR assessment and information about the functional integrity of coronary microcirculation distal to the site of CFR assessment.[4] CFR by TTD is a valuable research tool for investigating the pathophysiology of coronary circulation. However, CFR by TTD is also an important clinical decision-making instrument, enabling functional assessment of epicardial coronary stenosis, particularly in cases of anatomically borderline stenosis, i.e., 50%–70% of cases.[8] CFR by TTD enables insight downstream into coronary microvascular function that might be impaired due to primary coronary microvascular disease, as a consequence of myocardial diseases with extramural compression and microvascular remodeling and rarefaction (in left ventricular hypertrophy, dilated or hypertrophic cardiomyopathy, or aortic stenosis), or as a consequence of microvascular obstruction due to micro-embolization by plaque and thrombus debris during percutaneous coronary interventions.[9] Epicardial coronary artery patency and flow may be particularly jeopardized in the elderly as a result of advanced atherosclerosis (a disease of aging). Coronary microcirculatory function might also be impaired in the elderly even in the absence of obstructive epicardial atherosclerosis due to accumulated risk factors (e.g., hypertension, diabetes, obesity) and co-morbidities (e.g., chronic kidney, aortic stenosis).[10],[11] As a technique that is noninvasive, inexpensive, easily repeatable, and that does not require radiation, TTD CFR may be very useful in the fragile population of the elderly, offering a better understanding of coronary vascular aging as well as clinically important information regarding the diagnosis and prognosis of coronary artery disease.

Síndrome cardíaco X. Angina vasoespástica. Isquemia silente

Cardiac syndrome XThis is a clinical entity consisting of typical exertional angina, documented myocardial ischaemia and normal coronary arteries, in the absence of other heart disease. It pathogenic mechanisms are microvascular dysfunction and abnormal perception of chest pain. Stress echocardiogram with ST changes and chest pain with no parietal mobility anomalies supports the diagnosis. Measurement of coronary flow reserve during Doppler ultrasound of the anterior descending artery is an objective test of microvascular dysfunction. Vasospastic anginaThis comprises episodes of chest pain secondary to occlusive focal spasm of the epicardial arteries that normally present with ST elevation, as well as the more frequent episodes caused by diffuse distal spasm, with an ST descent. Tests that induce vasospasm are generally used to confirm the diagnosis such as intracoronary injection of acetylcholine. Silent ischaemiaAngina is a poor marker of mycoardial ischaemia, silent ischaemia is the most frequent manifestation of heart disease. In its most common form, type III, it coexists with angina of any type. Its diagnosis requires confirmation of myocardial ischaemia, usually by exercise stress test or Holter monitoring, in the absence of chest pain. The aim should be to treat the ischaemia, not just the angina.

Angiotensin-Converting Enzyme Inhibition Early After Heart Transplantation

BackgroundCardiac allograft vasculopathy (CAV) remains a leading cause of mortality after heart transplantation (HT). Angiotensin-converting enzyme inhibitors (ACEIs) may retard the development of CAV but have not been well studied after HT. ObjectivesThis study tested the safety and efficacy of the ACEI ramipril on the development of CAV early after HT. MethodsIn this prospective, multicenter, randomized, double-blind, placebo-controlled trial, 96 HT recipients were randomized to undergo ramipril or placebo therapy. They underwent coronary angiography, endothelial function testing; measurements of fractional flow reserve (FFR) and coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR); and intravascular ultrasonography (IVUS) of the left anterior descending coronary artery, within 8 weeks of HT. At 1 year, the invasive assessment was repeated. Circulating endothelial progenitor cells (EPCs) were quantified at baseline and 1 year. ResultsPlaque volumes at 1 year were similar between the ramipril and placebo groups (162.1 ± 70.5 mm3 vs. 177.3 ± 94.3 mm3, respectively; p = 0.73). Patients receiving ramipril had improvement in microvascular function as shown by a significant decrease in IMR (21.4 ± 14.7 to 14.4 ± 6.3; p = 0.001) and increase in CFR (3.8 ± 1.7 to 4.8 ± 1.5; p = 0.017), from baseline to 1 year. This did not occur with IMR (17.4 ± 8.4 to 21.5 ± 20.0; p = 0.72) or CFR (4.1 ± 1.8 to 4.1 ± 2.2; p = 0.60) in the placebo-treated patients. EPCs decreased significantly at 1 year in the placebo group but not in the ramipril group. ConclusionsRamipril does not slow development of epicardial plaque volume but does stabilize levels of endothelial progenitor cells and improve microvascular function, which have been associated with improved long-term survival after HT. (Angiotensin Converting Enzyme [ACE] Inhibition and Cardiac Allograft Vasculopathy; NCT01078363)

Neointimal Healing Evaluated by Optical Coherence Tomography after Drug-Eluting Absorbable Metal Scaffold Implantation in de novo Native Coronary Lesions: Rationale and Design of the Magmaris-OCT Study

Objectives: We sought to explore neointimal healing assessed by optical coherence tomography (OCT) following implantation of the Magmaris sirolimus-eluting absorbable metal scaffold. Methods: The Magmaris-OCT is a prospective, multicenter, single-arm observational clinical study, intended to enrol 60 consecutive patients with up to 2 de novo native coronary lesions, each located in different major epicardial vessels, with a reference vessel diameter of 2.5-3.5 mm, and a maximum lesion length of 20 mm. Patients will undergo Magmaris scaffold implantation in the target lesion, according to the standard practice. Clinical follow-up will take place at 30 days, and at 3, 6, 9, and 12 months. For invasive-imaging follow-up, patients will be classified into 3 groups: cohort A will be scheduled for follow-up at 3 months, cohort B at 6 months, and cohort C at 12 months. Invasive imaging will include quantitative coronary angiography, OCT evaluation, and coronary flow reserve measurement. The primary end point will be the percentage of uncovered scaffold struts assessed by OCT at the prespecified follow-up. Conclusions: This study will provide insight into the short- and mid-term healing properties following Magmaris scaffold implantation, with special emphasis on the neointimal coverage of scaffold struts.

Impact of high serum Immunoglobulin E levels on the risk of atherosclerosis in humans.

BackgroundEpidemiological studies show that immunoglobulin E (IgE) levels were higher in subjects with acute coronary events. However, it is unknown if the increased IgE level is a marker of future coronary incidents and whether it may be regarded as a risk factor of an ischemic heart disease.ObjectiveOur aim was to investigate the relationship between IgE levels and some atherosclerotic markers in patients without known atherosclerotic disease.MethodsFifty patients (mean age, 40.96 ± 10.8 years) with high serum IgE levels due to various conditions who did not display evidence of an atherosclerotic disease and 30 healthy control subjects (mean age, 47 ± 8.27 years) were included in the study. Atherosclerotic disease markers including adhesion molecules like vascular cell adhesion molecule-1, intercellular adhesion molecule-1, proinflammatory cytokines such as interleukin-6, endothelin-1, and systemic inflammatory markers such as high sensitivity C-reactive protein were determined by enzyme-linked immunosorbent assay (ELISA). Endothelial functions of the coronary arteries were determined by coronary flow reserve (CFR) measurements and carotid intima media thickness using transthoracic Doppler echocardiography.ResultsCFR was significantly lower in the patient group when compared with the control group (p<0.001; 95% confidence interval, -0.79 to-0.20) while carotid media thicknesses were not different between 2 groups. There were no differences in ELISA test results between the 2 groups.ConclusionOur results showed that CFR as an early marker of endothelial dysfunction was significantly lower in patients with high IgE levels. This finding seems to support the role of IgE in the vascular pathology of atherosclerosis.

Anomalous Coronary Arteries and Myocardial Bridges: Risk Stratification in Children Using Novel Cardiac Catheterization Techniques.

The evaluation of the vast majority of children with anomalous aortic origin of a coronary artery (AAOCA) and/or myocardial bridges is performed with non-invasive testing. However, a subset of these patients may benefit from invasive testing for risk stratification. All patients included in the Coronary Anomalies Program (CAP) at Texas Children's Hospital who underwent cardiac catheterization were included. Techniques included selective coronary angiograms (SCA), intravascular ultrasound (IVUS), and fractional flow reserve (FFR) measurements with provocative testing using adenosine and/or dobutamine infusions. Out of the 131 patients followed by the CAP between 12/12-4/16, 8 (6%) patients underwent 9 cath investigations at median age 13.1 (2.6-18.7) years and median weight 49.5 (11.4-142.7) kg. Six patients presented with cardiac signs/symptoms. Four patients had myocardial bridges of the left anterior descending (LAD) coronary artery, 2 patients had isolated AAOCA, and 2 patients had an anomalous left coronary artery (LCA) with an intramyocardial course of the LAD. SCA was performed in all patients. FFR was positive in 4/6 patients: IVUS showed >70% intraluminal narrowing in 3/5 patients. One patient had hemodynamic instability that reversed with catheter removal from the coronary ostium. Based on the catheterization data obtained, findings were reassuring in three patients, surgery was performed in three patients, and two patients are being medically managed/restricted from competitive sports. In our small cohort of patients, we demonstrated that IVUS and FFR can safely be performed in children and may help to risk stratify some patients with AAOCA and myocardial bridges.

473 - Coronary Fractional Flow Reserve (FFR) measurement: which method of adenosine administration is the safest?

473 - Coronary Fractional Flow Reserve (FFR) measurement: which method of adenosine administration is the safest?

Coronary fractional flow reserve measurements of a stenosed side branch: a computational study investigating the influence of the bifurcation angle.

BackgroundCoronary hemodynamics and physiology specific for bifurcation lesions was not well understood. To investigate the influence of the bifurcation angle on the intracoronary hemodynamics of side branch (SB) lesions computational fluid dynamics simulations were performed.MethodsA parametric model representing a left anterior descending—first diagonal coronary bifurcation lesion was created according to the literature. Diameters obeyed fractal branching laws. Proximal and distal main branch (DMB) stenoses were both set at 60 %. We varied the distal bifurcation angles (40°, 55°, and 70°), the flow splits to the DMB and SB (55 %:45 %, 65 %:35 %, and 75 %:25 %), and the SB stenoses (40, 60, and 80 %), resulting in 27 simulations. Fractional flow reserve, defined as the ratio between the mean distal stenosis and mean aortic pressure during maximal hyperemia, was calculated for the DMB and SB (FFRSB) for all simulations.ResultsThe largest differences in FFRSB comparing the largest and smallest bifurcation angles were 0.02 (in cases with 40 % SB stenosis, irrespective of the assumed flow split) and 0.05 (in cases with 60 % SB stenosis, flow split 55 %:45 %). When the SB stenosis was 80 %, the difference in FFRSB between the largest and smallest bifurcation angle was 0.33 (flow split 55 %:45 %). By describing the ΔPSB−QSB relationship using a quadratic curve for cases with 80 % SB stenosis, we found that the curve was steeper (i.e. higher flow resistance) when bifurcation angle increases (ΔP = 0.451*Q + 0.010*Q2 and ΔP = 0.687*Q + 0.017*Q2 for 40° and 70° bifurcation angle, respectively). Our analyses revealed complex hemodynamics in all cases with evident counter-rotating helical flow structures. Larger bifurcation angles resulted in more pronounced helical flow structures (i.e. higher helicity intensity), when 60 or 80 % SB stenoses were present. A good correlation (R2 = 0.80) between the SB pressure drop and helicity intensity was also found.ConclusionsOur analyses showed that, in bifurcation lesions with 60 % MB stenosis and 80 % SB stenosis, SB pressure drop is higher for larger bifurcation angles suggesting higher flow resistance (i.e. curves describing the ΔPSB−QSB relationship being steeper). When the SB stenosis is mild (40 %) or moderate (60 %), SB resistance is minimally influenced by the bifurcation angle, with differences not being clinically meaningful. Our findings also highlighted the complex interplay between anatomy, pressure drops, and blood flow helicity in bifurcations.

Assessment of coronary flow reserve using a combination of planar first-pass angiography and myocardial SPECT: Comparison with myocardial 15O-water PET

Coronary flow reserve (CFR), defined as the ratio of maximum coronary flow increase from baseline resting blood flow, is one of the most sensitive parameters to detect early signs of coronary arteriosclerosis at the microvascular level. Myocardial perfusion PET is a well-established technology for CFR measurement, however, availability is still limited. The aim of this study is to introduce and validate myocardial flow reserve measurement by myocardial perfusion SPECT. MethodsMyocardial perfusion SPECT at rest and ATP stress (0.16mg/Kg/min) was performed in 10 patients with known coronary artery disease. Immediately after the injection of Tc-99m sestamibi (MIBI), left ventricular (LV) dynamic planar angiographic data were obtained for 90s. Coronary flow reserve index as measured by MIBI SPECT (CFRMIBI) was calculated as follows: CFRMIBI=CmsSbmb/CmbSbms, where subscripts b, s, Cm, and Sbm indicate baseline, during stress, myocardial counts with MIBI SPECT, and integral of LV counts with first pass angiography, respectively. Additionally, standard stress/rest 15O-water PET to estimate CFR was performed in all patients as standard of reference. ResultsCFRMIBI increased in conjunction with CFR, but underestimated blood flow at high flow rates. The relationship between CFRMIBI (Y) and CFRPET (X) was well fitted as follows: Y=1.40x(1-exp(1.79/x)) (r=0.84). ConclusionsThe index of CFRMIBI reflects the CFR by 15O-water PET but underestimates flow at high flows, maybe as a reflection of pharmacokinetic limitations of MIBI.

Serial Assessment of Transthoracic Coronary Flow Reserve as Method of Assessing Efficacy of Intracoronary Intervention in the Left Anterior and Posterior Descending Arteries

The study group comprised 14 patients with single-vessel coronary disease (stenosis 82+/-14%) of the LAD (9 patients) or right coronary artery (RCA, 5 patients) scheduled for stent implantation. All patients underwent dipyridamole stress echo with CFR evaluation of either distal LAD or PDA 1 day before and 6-9 days after successful stent implantation. CFR was calculated as the ratio of hyperemic to basal peak diastolic velocity. A CFR value of <2.0 was considered abnormal. Adequate Doppler signals to measure CFR were obtained in 13 patients (93%). Abnormal pre-procedure CFR value was revealed in 12 assessed patients (92%). Significant increase of CFR due to a decrease of coronary flow velocity at rest and its more pronounced hyperemic rise was found in all patients after stent implantation (CFR: 1.28+/-0.52 before and 2.53+/-0.37 after stenting; p<0.001). Using a cut-off value of CFR more or equal 2.0 to identify absence of significant coronary artery disease, TTE detected successful stent implantation with a sensitivity of 91.7% and specificity of 100% for both LAD and RCA. CFR was still abnormal in only 1 patient with pre-procedure>90% LAD stenosis. TTE is a feasible technique for serial CFR evaluation in LAD and PDA. Cut-off CFR value more or equal 2.0 is a sensitive and specific criterion of successful stent implantation in LAD and RCA.

Effect of chronic inflammation on coronary arteries in renal amyloidosis: More than renal dysfunction

Effect of chronic inflammation on coronary arteries in renal amyloidosis: More than renal dysfunction