Coronary Flow Velocity Pattern Research Articles

A Closed-Loop Modeling Framework for Cardiac-to-Coronary Coupling.

The mechanisms by which cardiac mechanics effect coronary perfusion (cardiac-to-coronary coupling) remain incompletely understood. Several coronary models have been proposed to deepen our understanding of coronary hemodynamics, but possibilities for in-depth studies on cardiac-to-coronary coupling are limited as mechanical properties like myocardial stress and strain are most often neglected. To overcome this limitation, a mathematical model of coronary mechanics and hemodynamics was implemented in the previously published multi-scale CircAdapt model of the closed-loop cardiovascular system. The coronary model consisted of a relatively simple one-dimensional network of the major conduit arteries and veins as well as a lumped parameter model with three transmural layers for the microcirculation. Intramyocardial pressure was assumed to arise from transmission of ventricular cavity pressure into the myocardial wall as well as myocardial stiffness, based on global pump mechanics and local myofiber mechanics. Model-predicted waveforms of global epicardial flow velocity, as well as of intramyocardial flow and diameter were qualitatively and quantitatively compared with reported data. Versatility of the model was demonstrated in a case study of aortic valve stenosis. The reference simulation correctly described the phasic pattern of coronary flow velocity, arterial flow impediment, and intramyocardial differences in coronary flow and diameter. Predicted retrograde flow during early systole in aortic valve stenosis was in agreement with measurements obtained in patients. In conclusion, we presented a powerful multi-scale modeling framework that enables realistic simulation of coronary mechanics and hemodynamics. This modeling framework can be used as a research platform for in-depth studies of cardiac-to-coronary coupling, enabling study of the effect of abnormal myocardial tissue properties on coronary hemodynamics.

Abstract 12861: Assessment of Both Coronary Microvascular Damage and Epicardial Flow Velocity Measurement Immediately After Successful Percutaneous Coronary Intervention Predicts In-Hospital Complications and Survival in ST-Segment Elevation Myocardial Infarction

Background: Quantitative measurement of post-reperfusion epicardial flow velocity by a Doppler guidewire can predict clinical cardiac events in ST-segment elevation myocardial infarction (STEMI). It has also been reported that the coronary flow velocity pattern in patients with microvascular obstruction is characterized by the presence of early systolic retrograde flow and a rapid diastolic deceleration time (DDT). The purpose of this study was to examine the role of assessing both epicardial flow velocity and microvascular damage in the prediction of in-hospital complications and survival after percutaneous coronary intervention (PCI). Methods: Two hundred and fifty-one consecutive patients with first anterior STEMI who underwent successful PCI were subjected to coronary flow measurement with a Doppler guidewire. The coronary flow velocity spectrum provided the following parameters: time-averaged peak velocity (cm/s, APV), systolic peak velocity (cm/s) and DDT (ms). We defined the presence of microvascular obstruction as DDT ≤600 ms and the presence of systolic flow reversal, and slow epicardial flow as resting APV ≤10cm/s. We classified the patients into three categories: without microvascular obstruction (group 1, n=140), with microvascular obstruction and normal epicardial flow (group 2, n= 51, with microvascular obstruction and slow epicardial flow (group 3, n=60). The clinical event rate was compared among the 3 groups. Results: The in-hospital event rates for congestive heart failure (15/140 [11%], 15/51 [29%] and 34/60 [57%], respectively; P < 0.01), left ventricular thrombus (3/140 [2%], 9/51 [18%] and 14/60 [23%], respectively; P < 0.01), and cardiac rupture (0/140 [0%], 5/51 [10%], and 16/60 [27%]; P < 0.01) were highest in group 3 and lowest in group 1. Group 3 was at the highest risk of cardiac death, while group 1 was at the lowest (0/140 [0%], 3/51 [6%], and 12/60 [20%]; P < 0.01). Conclusions: Assessment of both coronary microvascular damage and epicardial flow velocity can accurately predict in-hospital complications and survival in STEMI patients who underwent successful reperfusion of the infarct-related coronary artery, identifying a subset of high risk patients.

Abstract 12943: Assessment of Both Coronary Microvascular Damage and Left Ventricular Chamber Stiffness After Successful Percutaneous Coronary Intervention Predicts Left Ventricular Aneurysm in ST-Segment Elevation Myocardial Infarction

Background: In ST-segment elevation myocardial infarction (STEMI), the short deceleration time of left ventricular (LV) early filling by Doppler is a powerful independent predictor of LV remodeling. On the other hand, recent studies have shown that even if successful reperfusion is achieved in epicardial coronary arteries, microvascular obstruction results in insufficient reperfusion of the infarcted myocardium, leading to LV dysfunction. The purpose of this study was to examine the effects of both microvascular damage and LV chamber stiffness on the risk of LV aneurysm after successful percutaneous coronary intervention (PCI) in STEMI patients. Methods: Two hundred and twenty-one consecutive patients with first anterior STEMI were studied following successful PCI. Microvascular damage was evaluated on the basis of coronary flow velocity patterns using Doppler guidewires. We defined the presence of microvascular obstruction as diastolic deceleration time of ≤600ms and the presence of systolic flow reversal. LV filling patterns were determined by LV inflow pulsed-wave Doppler examination on day 3 after STEMI. Deceleration time ≤130 ms was defined as restrictive. We classified patients into three categories: without restrictive and microvascular obstruction (group 1, n=125), with restrictive or microvascular obstruction (group 2, n= 43), and with restrictive and microvascular obstruction (group 3, n=53). Left ventriculogram obtained 6 months after the infarction was analyzed to measure the LV volume. True LV aneurysm was defined as a deformity of the infarct segment that was apparent during diastole as well as during systole, and demonstrated diastolic contour abnormality. Results: Group 3 was at the highest risk of true LV aneurysm, while group 1 was at the lowest (2/125 [2%], 15/43 [35%], and 30/53 [57%]; P<0.01). The assessment of both examinations was related to the LV volume index at 6 months after the infarction: patients in a poor group had a larger end-diastolic volume index (65±22 vs 91±28 vs 128±31ml/m2; P<0.01). Conclusions: Assessment of both microvascular damage and LV chamber stiffness can accurately predict the risk of LV aneurysm in STEMI patients who underwent successful reperfusion, identifying a subset of high risk patients.

Validation of high temporal resolution spiral phase velocity mapping of coronary artery blood flow against Doppler flow wire

Background The temporal pattern of coronary artery flow velocity through the cardiac cycle provides important information about coronary haemodynamics. The ‘gold standard’ for coronary artery velocity assessment is the Doppler flow wire which is inserted directly into the coronary artery under X-ray fluoroscopic guidance, which is invasive, uses ionising radiation and has a small but significant risk of serious complication. In this study, we perform an in vivo comparison of coronary blood flow velocities measured with breath-hold high temporal resolution spiral phase velocity mapping and Doppler flow wire measurements. Methods Breath-hold proximal coronary artery velocity maps were acquired in 5 left anterior descending (LAD) and 3 right coronary arteries (RCAs) in patients who had undergone invasive Doppler flow wire assessment as part of a clinical assessment. Acquisition parameters were: pixel size 1.4 × 1.4 mm (reconstructed to 0.7 ×0 .7 mm) ×8m m, true temporal resolution 19 ms, 1-1 water excitation (WE), 17 cardiac cycle breath-hold, velocity sensitivity 30-50cm/s, retrospective ECG gating (reconstructed 50 phases). Extraction of MR coronary artery blood flow velocitytime curves was performed using a custom MATLAB program which tracked the motion of the vessel over the cardiac cycle and corrected for the through-plane motion of the vessel using a region of adjacent tracked myocardium (LAD) or a region of surrounding epicardial fat (RCA) from a separately acquired fat-excitation acquisition. For each vessel, the mean through-plane motioncorrected MR velocities at all timepoints were plotted against the equivalent flow wire velocities. If necessary, the profiles were first time-shifted to take into account small differences in data triggering between the two techniques. The correlation between the two profiles was assessed using simple linear regression analysis. Results Figures 1 and 2 show example LAD and RCA studies. On average, the MR measured velocities were 66% less than the Flowire velocities (SD 9%, range: 50% - 78%). The correlation between the MR and flow wire data, however, was high, with R 2 values ranging from 0.6 - 0.95 in the 8 vessels studied (mean R 2 = .80).

Abstract 17083: Assessment of Both Coronary Microvascular Damage and Left Ventricular Chamber Stiffness after Successful Percutaneous Coronary Intervention Predicts In-Hospital Cardiac Complications and Left Ventricular Remodeling in ST-Segment Elevation Myocardial Infarction

Background: In ST-segment elevation myocardial infarction (STEMI), the short deceleration time of left ventricular (LV) early filling by Doppler is a powerful independent predictor of clinical cardiac events. It has also been reported that the coronary flow velocity pattern in patients with microvascular obstruction is characterized by the presence of early systolic retrograde flow and a rapid diastolic deceleration time (DDT). The purpose of this study was to examine the effects of both microvascular damage and LV chamber stiffness on cardiac complications and LV remodeling after successful percutaneous coronary intervention (PCI) in STEMI patients. Methods: Two hundred and one consecutive patients with first anterior STEMI were studied following successful PCI. Microvascular damage was evaluated on the basis of coronary flow velocity patterns using Doppler guidewires. We defined the presence of microvascular obstruction as DDT ≤600 ms and the presence of systolic flow reversal. LV filling patterns were determined by LV inflow pulsed-wave Doppler examination on day 3 after STEMI. Deceleration time ≤130 ms was defined as restrictive. We classified patients into three categories: without restrictive and microvascular obstruction (group 1, n=116), with restrictive or microvascular obstruction (group 2, n= 38), and with restrictive and microvascular obstruction (group 3, n=47). Left ventriculograms were obtained immediately and 6 months after PCI. LV remodeling was defined as an increase in end-diastolic volume index ≥20%. The clinical event rate was compared among the 3 groups. Results: The in-hospital event rates for LV thrombus (2/116 [2%], 5/38 [13%] and 14/47 [30%], respectively; P < 0.01) and congestive heart failure (5/116 [4%], 10/38 [26%], and 22/47 [47%]; P < 0.01) were highest in group 3 and lowest in group 1. Group 3 was at the highest risk of LV remodeling, while group 1 was at the lowest (7/116 [6%], 14/38 [37%], and 39/47 [83%]; P < 0.01). Conclusions: Assessment of both microvascular damage and LV chamber stiffness can accurately predict in-hospital complications and LV remodeling in STEMI patients who underwent successful reperfusion of the infarct-related coronary artery, identifying a subset of high risk patients.

Abstract 18884: Coronary Flow Velocity Pattern After Primary Percutaneous Coronary Intervention as a Predictor of Transmural Extent of Infarction in Patients with St-segment Elevation Acute Myocardial Infarction

Purpose: The purpose of this study was to investigate whether coronary flow velocity pattern after primary percutaneous coronary intervention (PCI) can predict the transmural extent of infarction (TEI) defined by contrast-enhanced cardiac magnetic resonance (ce-CMR) in patients with acute myocardial infarction (MI). Methods: In 91 patients after successful PCI for first acute MI, deceleration time of diastolic coronary flow velocity (DDT) were measured by transthoracic echocardiography. Ce-MRI were performed 7 days after onset of AMI. TEI was graded from 1 to 4 based on the transmural extent of hyperenhanced tissue (grade 1: 0-25% of left ventricular wall thickness, 2: 26-50%, 3: 51-75%, and 4: 76-100%). Infarct size by ce-CMR was also calculated. Results: Adequate recording of DDT were obtained in 87 of 91 patients (96%). Infarct size by ce-CMR and peak creatine kinase-myocardial band values were significantly correlated with DDT (r=0.54, p <0.0001 and (r=0.40, p=0.006, respectively). Moreover, decreased DDT was significantly related to increased TEI-grade (p< 0.0001) (figure) and existence of microvascular obstruction (p<0.0001). Conclusion: DDT measured after primary PCI is a useful predictor for the TEI in patients with acute MI.

Assessment of Coronary Artery Flow Velocity Pattern as a Long-Term Predictor of Left Ventricular Function and Cardiac Events after Percutaneous Coronary Intervention in Anterior Acute Myocardial Infarction

Coronary flow velocity (CFV) can be used to assess short-term left ventricular function recovery and the clinical prognosis of patients with acute myocardial infarction (AMI). We evaluated CFV as a predictor of long-term left ventricular function recovery and cardiac events in patients with anterior wall AMI. CFV pattern of the distal left anterior descending (LAD), wall motion score index (WMSI) and left ventricular ejection fraction (LVEF) were recorded at the points of time within 24 hours, 3 days, 6 months, and 3 years after percutaneous coronary intervention (PCI) in 50 consecutive patients with anterior wall AMI. The clinical data were collected. Patients were divided into two groups based on diastolic deceleration time (DDT) 3 days after PCI. Compared with 3 days, LVEF and WMSI in group A (DDT>600 ms, n=20) improved in 6 months and 3 years (p<0.01), but they were unchanged in group B (DDT< or =600 ms, n=30). The incidence of cardiac events was higher in group B than in group A during 6 months (p<0.01).With a 3-year follow up, the incidence of chronic heart failure was higher in group B than in group A (p=0.009). CFV could be used as a predictor of long-term left ventricular function recovery and cardiac events in patients with anterior wall AMI.

Abstract 4473: Coronary Flow Velocity Pattern Immediately after Percutaneous Coronary Intervention Predicts True Left Ventricular Aneurysm in Patients with Acute Anterior Myocardial Infarction

Aggressive management of acute myocardial infarction (AMI), including prompt reperfusion, may diminish the incidence of true left ventricular (LV) aneurysm; however, it has been reported that even if successful reperfusion is achieved in epicardial coronary arteries, microvascular dysfunction causes insufficient reperfusion of the infracted myocardium, leading to LV dysfunction. Recent studies have shown that microvascular damage can be assessed quantitatively from coronary flow velocity (CFV) patterns immediately after successful reperfusion. The purpose of this study was to examine whether the CFV patterns may predict the risk of true LV aneurysm formation following successful percutaneous coronary intervention (PCI). Two hundred and one consecutive patients with first anterior AMI who underwent successful PCI were subjected to CFV measurement immediately after PCI with Doppler guidewires. The CFV spectrum provided systolic peak velocity (cm/s, SPV) and diastolic deceleration time (ms, DDT). Left ventriculogram obtained 6 months after the infarction was analyzed to measure the LV volume index. True LV aneurysm was defined as a deformity of the infarct segment that was apparent during diastole as well as during systole, and demonstrated diastolic contour abnormality. Patients were divided into the two groups: those subsequently complicated by true LV aneurysm (n=42; group 1) and those without true LV aneurysm (n=159; group 2) CFV analysis immediately after PCI showed significantly lower SPV (−29 ± 17 vs. 5 ± 22 cm/s; p&lt;0.001) and shorter DDT (317 ± 156 vs. 665 ± 204 ms; p&lt;0.001) in group 1 than in group 2. The optimal cutoff values to predict true LV aneurysm formation were −20 cm/s for SPV and 400 ms for DDT (sensitivity=0.83, specificity=0.82; and sensitivity=0.81, specificity=0.87, respectively). SPV and DDT correlated to the LV end-diastolic volume index obtained 6 months after AMI (r= −0.67; p&lt;0.001 and r = −0.78; p&lt;0.001, respectively). CFV pattern of infarct-related coronary artery immediately after PCI predicts true LV aneurysm formation, and enables accurate risk stratification in patients with anterior AMI.

Abstract 901: Impact of Microvascular Dysfunction on Long-Term Cardiovascular Events after Primary Coronary Intervention for Acute Myocardial Infarction in Patients Achieving TIMI Grade 3 Reperfusion

It has been reported that even if TIMI 3 flow is achieved in epicardial coronary arteries after primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI), microvascular dysfunction results in insufficient reperfusion. Recent studies have shown that microvascular injury can be assessed from coronary flow velocity (CFV) pattern. The aim of this prospective study was to examine whether the CFV pattern predicts the long-term cardiovascular outcomes in AMI patients who achieved TIMI grade 3 reperfusion. The study population consisted of 161 consecutive patients with a first anterior AMI successfully treated with primary PCI (≤50% residual stenosis with TIMI grade 3). We examined the CFV pattern immediately after PCI using a Doppler guidewire. We defined microvascular dysfunction as a diastolic deceleration time ≤600 ms and the presence of systolic flow reversal. Patients were divided into two groups: those without microvascular dysfunction (n=126; group 1) and those with micriovascular dysfunction (n=35; group 2). We evaluated the association between the microvascular dysfunction and the long-term major adverse cardiovascular event (MACE) rates. The Kaplan-Meier survival curves showed that group 2 was poorer than group 1 in prognosis (p=0.0014). Risk-adjusted data by multivariate analysis showed that the microvascular dysfunction was the strongest predictor for long-term MACE (hazard ratio: 3.37; 95% CI, 1.59–7.15; p=0.0015). The CFV pattern immediately after PCI is an accurate predictor of the long-term cardiovascular outcomes in patients with AMI who achieved TIMI grade 3 reperfusion.

Abstract 4910: Integrated Approach By Using Coronary Flow Velocity Reserve And Coronary Flow Velocity Patterns In Predicting Long-term Adverse Cardiac Events In Acute Myocardial Infarction

Background: The microvascular function was known to be an useful predictor of left ventricular functional changes and clinical outcomes in ST-segment elevation myocardial infarction (STEMI). We evaluated the usefulness of integrated approach by using coronary flow velocity reserve (CFR) and diastolic deceleration time (DDT) in the prediction of long-term major adverse cardiac events in STEMI. Methods and Results: Using an intracoronary Doppler wire, CFR, DDT and hyperemic microvascular resistance index (MVRI) were evaluated in 202 patients with first STEMI received reperfusion therapy within 24 hours after onset of symptoms. Major adverse cardiac events were the composite of cardiac death, recurrent myocardial infarction, congestive heart failure and stroke during an average follow-up period of 60 ± 39 months. Follow-up echocardiography was performed at 12 ± 9 months. CFR, DDT and MVRI had significant correlations with left ventricular regional wall motion score index at follow-up echocardiography (r =−0.441, p&lt;0.001; r = 0.413, p&lt;0.001; r =−0.485, p&lt;0.001, respectively). Using receiver-operating characteristics analysis, CFR ≤1.3 (sensitivity: 51%, specificity: 78%), DDT ≤577 ms (sensitivity: 72%, specificity: 62%) and MVRI &gt;2.7 (sensitivity: 68%, specificity: 67%) were the best cutoff values in the prediction of occurring the adverse cardiac events. In patients with CFR ≤1.3, DDT ≤577 ms, cardiac events were occurred in 18 patients (40.0 %) of 45 patients, whereas cardiac events were occurred in 12 patients (20.3%) of 59 patients with CFR &gt;1.3 and DDT ≤577 ms or CFR ≤1.3 and DDT &gt;577 ms (p= 0.048), 9 patients (9.1%) of 99 patients with CFR&gt;1.3 and DDT &gt;577 ms (p&lt;0.001). Ejection fraction at admission (p=0.009), MVRI (p =0.002) and DDT (p=0.023) were independent predictors in the prediction of long-term adverse cardiac outcomes during follow-up. Conclusions: Integrated approach by using CFR and DDT was useful in the prediction of long-term adverse cardiac events. MVRI and DDT were strong independent predictors of long-term adverse cardiac events in STEMI patients.

Abstract 2513: Assessment of Both Coronary Microvascular Damage and Epicardial Flow Velocity Measurement Immediately after Successful Percutaneous Coronary Intervention for Acute Myocardial Infarction Predicts In-Hospital Complications and Survival

Quantitative measurement of post-reperfusion epicardial flow velocity by a Doppler guidewire can predict clinical cardiac events in patients with acute myocardial infarction (AMI). It has also been reported that the coronary flow velocity pattern in patients with microvascular dysfunction is characterized by the presence of early systolic retrograde flow and a rapid diastolic deceleration time (DDT). The purpose of this study was to examine the role of assessing both epicardial flow velocity and microvascular damage in the prediction of in-hospital complications and survival after percutaneous coronary intervention (PCI). Two hundred and eleven consecutive patients with first anterior AMI who underwent successful PCI were subjected to coronary flow measurement immediately after successful PCI with a Doppler guidewire. The coronary flow velocity spectrum provided the following parameters: time-averaged peak velocity (cm/s, APV), systolic peak velocity (cm/s) and DDT (ms). We defined the presence of microvascular dysfunction as DDT ≤600 ms and the presence of systolic flow reversal, and slow epicardial flow as resting APV ≤10cm/s. We classified the patients into three categories: without microvascular dysfunction (group 1, n=122), with microvascular dysfunction and normal epicardial flow (group 2, n= 54), with microvascular dysfunction and slow epicardial flow (group 3, n=35). The clinical event rate was compared among the 3 groups. The in-hospital event rates for congestive heart failure, cardiac rupture and death were highest in group 3 and lowest in group 1 (Table ). Assessment of both coronary microvascular damage and epicardial flow velocity can accurately predict in-hospital complications and survival in AMI patients who underwent successful reperfusion of the infarct-related coronary artery, identifying a subset of high risk patients. In-hospital event rates (%)

Abstract 4206: Microvascular Dysfunction and Left Ventricular Chamber Stiffness after Successful Percutaneous Coronary Intervention Critically Determine Left Ventricular Remodeling in Patients with Acute Myocardial Infarction

In patients with acute myocardial infarction (AMI), the short deceleration time of left ventricular (LV) early filling by Doppler is a powerful independent predictor of LV remodeling. On the other hand, recent studies have shown that microvascular dysfunction in recanalized infarct-related coronary arteries may predict progressive LV dilation. The purpose of this study was to examine the effects of both microvascular dysfunction and LV chamber stiffness on LV remodeling after successful percutaneous coronary intervention (PCI) in AMI patients. Two hundred and one consecutive patients with first anterior AMI were studied following successful PCI. Microvascular injury was evaluated on the basis of coronary flow velocity patterns immediately after successful PCI using Doppler guidewires. We defined the presence of microvascular dysfunction as diastolic deceleration time ≤600 ms and the presence of systolic flow reversal. LV filling patterns were determined by mitral inflow pulsed-wave Doppler examination on day 3 after AMI. Deceleration time ≤130 ms was defined as restrictive. We classified the patients into three categories: without restrictive and microvascular dysfunction (group 1, n=116), with restrictive or microvascular dysfunction (group 2, n= 38), and with restrictive and microvascular dysfunction (group 3, n=47). Left ventriculograms were obtained immediately and 6 months after PCI. LV remodeling was defined as an increase in end-diastolic volume index ≥20%. Group 3 was at the highest risk of LV remodeling, while group 1 was at the lowest (Table ). Assessment of both microvascular dysfunction and LV chamber stiffness enable accurate prediction of LV remodeling in AMI patients after successful PCI. LV remodeling in each group

Ultrasonic Strain Versus Coronary Flow Velocity Pattern for Predicting Regional Wall Motion Recovery After Primary Coronary Intervention for Acute Myocardial Infarction

Strain Doppler echocardiography can detect regional myocardial dysfunction after acute myocardial infarction (AMI). The aim of this study was to assess the utility of strain in predicting regional wall motion recovery after AMI compared with the coronary flow velocity pattern. Thirty-three patients with anterior AMIs undergoing successful coronary intervention were included. Longitudinal myocardial strain and coronary flow velocity were measured <24 hours after coronary intervention. Regional wall motion was analyzed by the anterior wall motion score index (A-WMSI). End-systolic strain (r = 0.72, P < .0001), peak strain (r = 0.58, P < .005), and corrected time to peak strain (the time delay from end-systolic to peak strain divided by the RR interval) (r = 0.80, P < .0001) showed good correlations with A-WMSI at 4 weeks. Similarly, diastolic deceleration time was significantly correlated with A-WMSI at 4 weeks (r = 0.69, P < .0001). The diagnostic value in predicting wall motion recovery was compared using a receiver operating characteristic curve. The area under the curve of corrected time to peak strain tended to be larger than that of diastolic deceleration time (0.94 +/- 0.04 vs 0.86 +/- 0.06). Strain can predict left ventricular wall motion recovery in patients with AMIs after coronary intervention comparable with predictions using the coronary flow velocity pattern.

No reflow-like pattern in intramyocardial coronary artery suggests myocardial ischemia in patients with hypertrophic cardiomyopathy

To evaluate intramyocardial coronary flow velocity pattern by transthoracic Doppler echocardiography and its clinical significance in patients with hypertrophic cardiomyopathy (HCM). In 48 patients with HCM who had angiographically normal coronary artery, coronary flow velocity in the left anterior descending coronary artery (LAD) and intramyocardial coronary artery (IMCA) derived from LAD were evaluated using transthoracic Doppler echocardiography. Two clearly different flow patterns in the IMCA were observed in patients with HCM. Twenty-seven HCM patients (group A) had slow deceleration slope in the IMCA flow (average diastolic deceleration time, 989+/-338; range, 585-1680) and the remaining 21 patients (group B) had steep deceleration slope with diastolic deceleration time <300 ms, resulting in a no reflow-like pattern in the IMCA flow (average diastolic deceleration time, 166+/-67; range, 55-280). There were no significant differences in the clinical characteristics and LAD flow velocity profiles between the two groups. The incidence of cardiovascular symptoms (chest pain or syncope) was significantly higher in group B than in group A (67% vs. 26%, p<0.01). Additionally, exercise-induced ischemia as detected by thallium-201 scintigraphy was significantly more frequent in group B than in group A (6 of 9 (67%) vs. 0 of 9 (0%), p<0.01). Two different intramyocardial coronary flow velocity patterns are observed in patients with HCM using transthoracic Doppler echocardiography. No reflow-like pattern in the IMCA is strongly related to myocardial ischemia in the absence of epicardial coronary artery stenosis, suggesting that coronary microvascular dysfunction may be a causative mechanism.

Relation Between the Assessment of Microvascular Injury by Cardiovascular Magnetic Resonance and Coronary Doppler Flow Velocity Measurements in Patients With Acute Anterior Wall Myocardial Infarction

We studied the relation between presence and severity of microvascular obstruction (MO), measured by cardiovascular magnetic resonance (CMR) and intracoronary Doppler flow measurements, for assessment of myocardial reperfusion in patients with acute anterior myocardial infarction (MI) treated by primary percutaneous coronary intervention (PCI). Cardiovascular magnetic resonance has been used to detect and quantify MO in patients after acute MI but has never been compared with coronary blood flow velocity patterns. Twenty-seven patients with first anterior ST-segment elevation MI successfully treated with primary PCI were included. Coronary blood flow velocity was measured during recatheterization 4 to 8 days after primary PCI. These measurements were related to MO determined by late gadolinium-enhanced (LGE) CMR performed the day before recatheterization. Early systolic retrograde flow was observed in 0 of 8 patients without MO on LGE CMR and in 10 (53%) of 19 patients with MO (p = 0.01). The extent of MO correlated with the diastolic-systolic velocity ratio (r = 0.44; p = 0.02), diastolic deceleration time (r = -0.61; p = 0.001), diastolic deceleration rate (r = 0.75; p < 0.0001), and coronary flow velocity reserve of the infarct-related artery (r = -0.44; p = 0.02). Furthermore, multivariate regression analyses, including extent of MO, infarct size, and transmural necrosis on LGE CMR, revealed that extent of MO was the only independent factor related to early systolic retrograde flow and diastolic deceleration rate. Assessment of microvascular injury by LGE CMR corresponds well to evaluation by intracoronary Doppler flow measurements. By means of CMR, quantification of myocardial function, infarct size, and microvascular injury can accurately be performed with a single noninvasive technique in patients with acute MI.

Correlation Between the Serum Bilirubin Level and the Coronary Microvascular Integrity in Diabetic Patients

Background and Objectives: Bilirubin has a protective role in suppressing atherosclerosis and coronary artery disease by its potent physiological antioxidant properties. There has been no comparative study on the relation between the bilirubin level and the coronary microvascular function in diabetic patients. This study investigated whether the bilirubin level correlates with the coronary microvascular integrity in diabetes by assessing the coronary flow velocities after successful percutaneous coronary intervention (PCI). Subjects and Methods: Fifty patients (31 males and 19 females, mean age 60±11) with angina and who received elective PCI were studied. Using an intracoronary Doppler wire, the coronary flow velocity reserve (CFR), the hyperemic microvascular resistance index and the phasic coronary flow velocity patterns were measured after PCI. Results: The mean value of the fasting blood glucose was 211±88 mg/dL, the man value of glycated hemoglobin A1c (HbA1c) was 8.1±1.6% and the mean serum total bilirubin level was 0.59±0.21 mg/dL. CFR was significantly correlated with the serum bilirubin level (r=0.485, p<0.001), HbA1c (r=-0.432, p=0.003) and the fasting blood glucose (r=-0.361, p=0.011). On multivariate analysis, HbA1c, bilirubin and left ventricular hypertrophy showed independent relationships with coronary microvascular dysfunction (p=0.003, p=0.004, p=0.033, respectively). Conclusion: These results suggest that glycemic control and elevated serum bilirubin may protect diabetic patients from coronary microvascular dysfunction. (Korean Circ J 2008;38:425-431)

Abstract 3340: Coronary Flow Velocity Pattern Immediately After Percutaneous Coronary Intervention Predicts Left Ventricular Remodeling in Patients with Acute Myocardial Infarction

Background: Studies using the Doppler guidewire have shown that coronary flow velocity (CFV) pattern in recanalized infracted arteries predicts recovery of regional left ventricular (LV) function, in-hospital complications, and long-term cardiac events. However, the relationship between the CFV pattern after reperfusion and serial changes in LV volumes is not clear. We postulated that the quantitative CFV measurement immediately after successful percutaneous coronary intervention (PCI) might be associated with the LV remodeling. To test this hypothesis, we prospectively analyzed the LV remodeling according to CFV parameters measured by the Doppler guidewire in patients with acute myocardial infarction (AMI). Methods: Consecutive 211 patients with first-time anterior AMI underwent successful PCI (&lt;50% residual stenosis with TIMI flow grade 2–3) and coronary flow measurement with the Doppler guidewire. The CFV spectrum provided the following parameters: time-averaged peak velocity (cm/s), systolic peak velocity (cm/s), and diastolic deceleration time (ms). Left ventriculograms obtained immediately after PCI and 6 months after the infarction were analyzed to measure the end-diastolic volume index and end-systolic volume index. The LV remodeling was defined as an increase in end-diastolic volume index ≥20%. Result: The optimal cutoff values to predict LV remodeling (defined as 6-month LV dilation ≥20%) were 20 cm/s for time-averaged peak velocity, 0 cm/s for systolic peak velocity and 550 ms for diastolic deceleration time (sensitivity=0.63, specificity=0.56; sensitivity=0.76, specificity=0.85; and sensitivity=0.85, specificity=0.85, respectively). Systolic peak velocity and diastolic deceleration time correlated to the LV end-diastolic volume index obtained 6 months after AMI(r= −0.67; p&lt;0.001 and r= −0.78; p&lt;0.001, respectively). Conclusions: The CFV pattern appears to be an accurate predictor of LV remodeling even in patients who received successful PCI in the left anterior descending coronary artery immediately after AMI. This index, therefore, identifies a subset of patients at-risk.

Relationship between Microvascular Resistance and Perfusion in Patients with Reperfused Acute Myocardial Infarction

Despite its prognostic importance, accurate assessment of microvascular perfusion in patients with ST elevation acute myocardial infarction (STEMI) is difficult. As a new tool, the index of microvascular resistance (IMR) measurement provides us a new opportunity for interrogating microvascular condition after STEMI. In this study, we measured IMR in infarct-related artery (IRA) and explored its relation with other indices which have been suggested to evaluate microvascular perfusion in patients with reperfused STEMI. Forty-two patients with STEMI treated successfully with primary percutaneous coronary intervention (pPCI) were prospectively included. After 48 hours following pPCI, patients were recatheterized and IMR, coronary flow reserve (CFR), systolic and mean coronary wedge pressures (CWPs and CWPm) pressure-derived collateral flow index (CFIp) were measured in IRA by using intracoronary pressure-temperature sensor tipped guide wire. Myocardial blush grade was assessed from the second angiogram. Coronary flow velocity pattern (diastolic deceleration time: DDT) was examined with transthoracic echocardiography 48 hours after pPCI. Percentage of ST-segment recovery was calculated from surface ECG (STR%). IMR well correlated with CWPs (r = 0.70, P < 0.001), CWPm (r = 0.59, P < 0.001), CFIp (r = 0.65, P < 0.001), CFR (r =-0.50, P = 0.001), and DDT (r =-0.59, P = 0.001). Correlations of IMR to non/semiinvasive indices like myocardial blush grades (MBG) (r =-0.42, P = 0.007) and STR (r =-0.37, P = 0.024) are somewhat weaker. Given its simplicity of measurement, independence from the presence of an epicardial stenosis, and good correlation with all measures of microvascular obstruction used in this study, IMR may prove to be a valuable modality for evaluating the microcirculation.

Transthoracic Doppler Echocardiographic Assessment of Left Anterior Descending Coronary Artery and Intramyocardial Artery Predicts Left Ventricular Remodeling and Wall-motion Recovery After Acute Myocardial Infarction

Previous studies reported that a coronary flow velocity (FV) pattern with a rapid diastolic deceleration time (DDT) immediately after percutaneous coronary intervention implies advanced microvascular damage in patients who have experienced an acute myocardial infarction (AMI). Using transthoracic echocardiography, we recorded the coronary FV in the left anterior descending coronary artery (LAD) and the FV in the intramyocardial artery 2 days after successful percutaneous coronary intervention in 24 patients who had experienced an anterior AMI. We measured the DDT of the LAD and the intramyocardial artery. DDT of the LAD and the intramyocardial artery was detected in the anteroseptal lesion, the wall motion of which revealed severe hypokinesis or akinesis. We performed echocardiography during both the acute phase and 6 months after the AMI. Patients were divided into two groups (group A: DDT of the LAD < or = 600 milliseconds [n = 10], group B: DDT of the LAD > or = 600 milliseconds [n = 14]). DDT of the LAD and the intramyocardial artery was significantly shorter for group A than group B (373 +/- 223 vs 786 +/- 105 milliseconds, P < .0001). In the acute phase, there were no significant differences in left ventricular (LV) wall-motion score index (WMSI), LV end-diastolic volume (EDV), or ejection fraction (WMSI: 2.38 +/- 0.24 vs 2.08 +/- 0.58, P = .20; LV EDV: 160 +/- 41 vs 154 +/- 34 mL; ejection fraction: 45 +/- 11 vs 46 +/- 5%). However, WMSI and LV EDV in group A were significantly greater than in group B (WMSI: 2.47 +/- 0.16 vs 1.84 +/- 0.57, P = .01; LV EDV: 198 +/- 28 vs 132 +/- 37 mL, P = .0004) and the ejection fraction in group A was significantly lower than in group B (38 +/- 9 vs 55 +/- 10%, P = .001) during the chronic phase. In patients who had experienced an anterior AMI, we could predict wall-motion recovery of the infarcted area by using the coronary FV of the LAD and FV of the intramyocardial artery.

Sequential Transthoracic Ultrasound Assessment of Coronary Flow Reserve in a Patient with Tako-tsubo Syndrome

We report a case of a 70-year-old woman with Tako-tsubo syndrome admitted to the hospital with typical chest pain and electrocardiogram changes in anterior precordial leads suggesting acute coronary syndrome. Coronary angiography demonstrated normal coronary artery and left ventriculography the typical apical ballooning of Tako-tsubo syndrome. Transthoracic echocardiographically derived coronary flow velocity reserve by adenosine was lower than normal (1.54) in the acute phase and improved after 1 month (2.68). At this time, electrocardiogram normalization also occurred. Our report supports the hypothesis that coronary microvascular dysfunction might be a determinant of Tako-tsubo syndrome.