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. METHODS: 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%). RESULTS: 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. CONCLUSION: 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.     

Effect of distal protection device on the microvascular integrity in acute myocardial infarction during primary percutaneous coronary intervention.

BACKGROUND: The use of a distal protection device during primary percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) may preserve the microvascular integrity of the myocardium. METHODS AND RESULTS: A total of 58 consecutive patients with AMI, who had undergone primary PCI within 24 h after onset, were enrolled (30 patients with the PercuSurge GuardWire System, 28 without). The coronary flow velocity reserve was not different between the 2 groups. In patients with a distal protection device, the post-PCI Thrombolysis In Myocardial Infarction myocardial perfusion grades (TMP) were more favorable (TMP 0/1: 13.3%, TMP 2: 23.3%, TMP 3: 63.4% vs TMP 0/1: 35.7%, TMP 2: 35.7%, TMP 3: 28.6%, p=0.023). These patients also exhibited lower basal and hyperemic microvascular resistance index levels (4.33+/-2.22 vs 5.55+/-2.36 mmHg . cm(-1) . s, p=0.047; 2.39+/-1.40 vs 3.14+/-1.36 mmHg . cm(-1) . s, p=0.045, respectively), and longer basal diastolic deceleration time (679+/-273 vs 519+/-289 ms, p=0.035) after PCI. CONCLUSION: Distal protection with the PercuSurge GuardWire system may effectively preserve the microvascular integrity of the myocardium during primary PCI in AMI patients.     

Relation between neutrophil counts on admission, microvascular injury, and left ventricular functional recovery in patients with an anterior wall first acute myocardial infarction treated with primary coronary angioplasty

Increased neutrophil counts have been associated with an increased risk of adverse clinical events after acute myocardial infarction (AMI). We examined the association of neutrophil counts on admission with degree of microvascular injury and left ventricular functional recovery after primary coronary angioplasty in AMI. We studied 116 patients with a first anterior wall AMI who underwent primary coronary angioplasty within 12 hours of onset. Patients were categorized into 3 groups based on initial neutrophil count: low (<5,000/mm(3)), intermediate (5,000 to 10,000/mm(3)), and high (>10,000/mm(3)). Coronary flow velocity parameters were assessed immediately after reperfusion using a Doppler guidewire. We defined severe microvascular injury as the presence of systolic flow reversal and a diastolic deceleration time <600 ms. Echocardiographic wall motion was analyzed before revascularization and 4 weeks after revascularization. In patients with a high neutrophil count, systolic flow reversal was more frequently observed, diastolic deceleration time was shorter, and coronary flow reserve was lower. By regression analysis, neutrophil count significantly correlated with diastolic deceleration time (r = -0.38, p <0.0001), coronary flow reserve (r = -0.33, p = 0.0004), and score for change in wall motion (r = -0.36, p = 0.0004). Multivariate analysis showed that neutrophil count on admission was an independent predictor of severe microvascular injury (odds ratio 2.94, p = 0.02). In conclusion, neutrophilia on admission is associated with impaired microvascular reperfusion and poor functional recovery after primary coronary angioplasty.     

Predictive value of the index of microcirculatory resistance in patients with ST-segment elevation myocardial infarction.

OBJECTIVES: The objective of this study is to evaluate the predictive value of the index of microcirculatory resistance (IMR) in patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). BACKGROUND: Despite adequate epicardial artery reperfusion, a number of patients with STEMI have a poor prognosis because of microvascular damage. Assessing the status of the microvasculature in this setting remains challenging. METHODS: In 29 patients after primary PCI for STEMI, IMR was measured with a pressure sensor/thermistor-tipped guidewire. The Thrombolysis In Myocardial Infarction (TIMI) myocardial perfusion grade, TIMI frame count, coronary flow reserve, and ST-segment resolution were also recorded. RESULTS: The IMR correlated significantly with the peak creatinine kinase (CK) (R = 0.61, p = 0.0005) while the other measures of microvascular dysfunction did not. In patients with an IMR greater than the median value of 32 U, the peak CK was significantly higher compared with those having values 32 U compared with 相似文献   

Clinical significance of coronary flow reserve in hypertrophied heart: comparison with Doppler index, hemodynamics and plasma natriuretic peptide concentrations

OBJECTIVES: The relationship was investigated between coronary flow reserve and Doppler echocardiographic parameters, hemodynamic parameters and plasma natriuretic peptide concentrations in the hypertrophied heart. METHODS: The subjects were 19 patients with hypertrophied heart due to various etiologies and no significant coronary artery stenosis. All patients were in sinus rhythm. The left ventricular wall thickness, the E/A ratio in transmitral flow velocity pattern and the Doppler index were determined by Doppler echocardiography, and the plasma atrial and brain natriuretic peptide concentrations were measured. At cardiac catheterization, pulmonary capillary wedge pressure and left ventricular end-diastolic pressure were measured, and the coronary flow reserve was obtained by injecting intracoronary adenosine triphosphate into the left anterior descending artery using a Doppler guidewire. RESULTS: Coronary flow reserve in the patients was significantly lower than in 11 normal control subjects (2.50 +/- 0.76 vs 3.90 +/- 0.64, p < 0.001). There were no significant correlations between coronary flow reserve and the left ventricular wall thickness or the E/A ratio. The mean value of the Doppler index in the patients was 0.48 +/- 0.10 and there was a significant negative correlation between coronary flow reserve and the Doppler index (r = -0.73, p < 0.001). The correlation between coronary flow reserve and left ventricular end-diastolic pressure was not significant, but there was a significant negative correlation between coronary flow reserve and pulmonary capillary wedge pressure (r = -0.64, p < 0.01). There were significant negative correlations between coronary flow reserve and atrial (r = -0.62, p < 0.01), or brain natriuretic peptide concentrations (r = -0.56, p < 0.05). CONCLUSIONS: Coronary flow reserve may reflect overall cardiac performance evaluated by the Doppler index and plasma natriuretic peptide concentrations in the hypertrophied heart, and the measurement of coronary flow reserve may be useful for evaluating disease severity in patients with hypertrophied heart.     

Noninvasive assessment of myocardial damage after acute anterior myocardial infarction: myocardial blush grade in conjunction with analysis of coronary flow pattern

In patients with acute myocardial infarction (AMI), both myocardial blush grade (MBG) and coronary flow pattern obtained by transthoracic Doppler echocardiography (TTDE) have limitations in assessing myocardial viability. Accordingly, we assessed the usefulness of combination of MBG and TTDE in predicting myocardial damage following AMI. A total of 45 patients with anterior AMI were enrolled. Myocardial blush grade and coronary flow velocity (CFV), diastolic deceleration time (DDT), and coronary flow velocity reserve (CFVR) were measured immediately after reperfusion. The regional wall motion score index (RWMSI) was measured at 14 days after onset. The MBG was normal in 12 patients. The RWMSI was significantly better in the patients with normal than with abnormal MBG (1.65 ± 0.29 vs 2.03 ± 0.46, P < 0.05). Among the coronary flow indices, only DDT showed the significant correlation with RWMSI (P < 0.05, r = −0.44). To predict RWMSI ≥2, sensitivity and positive predictive value (PPV) were 86.3% and 65.5% in DDT alone, 90.9% and 65.5% in MBG alone, respectively. Predictable value was enhanced by the combination with DDT and MBG, with sensitivity of 100% and PPV of 70.8% in 31 patients whose results of both corresponded. MBG in conjunction with TTDE was useful in predicting myocardial damage after anterior AMI.     

Coronary vascular reserve in left ventricular hypertrophy secondary to chronic aortic regurgitation

Coronary vascular reserve was studied in 11 patients with severe chronic aortic regurgitation (AR). Nineteen patients with the chest pain syndrome and normal findings on cardiac catheterization served as control subjects. Resting coronary sinus flow and contrast-agent-induced hyperemia were measured by continuous thermodilution. Left ventricular (LV) dimensions and mass were obtained echocardiographically. All patients had normal coronary arteries. Resting coronary flow was increased and coronary reserve was decreased in patients with AR compared with the control subjects: 310 +/- 38 versus 121 +/- 13 ml/min and 56 +/- 9 versus 86 +/- 7.5%, respectively. The decrease in coronary vascular reserve correlated with the increase in LV mass (r = -0.86, p = 0.001) and LV wall thickness (r = -0.83, p = 0.002) and with the decrease in LV volume/mass ratio (r = 0.761, p = 0.007). There was no significant correlation between the decrease in coronary vascular reserve and LV volume (r = 0.255), LV peak wall stress (r = 0.292), LV systolic pressure (r = -0.495), aortic or LV diastolic pressure (r = 0.322 and -0.318, respectively), or aortic-LV diastolic gradient, nor with the voltage on the electrocardiogram (limb leads r = -0.60, precordial leads r = -0.118). Thus, coronary vascular reserve is decreased in proportion to the degree of left ventricular hypertrophy in patients with chronic AR. Patients with angina pectoris tended to have a lower coronary vascular reserve than those without angina (median 26 versus 76%, difference not significant). LV wall thickness and not LV volume is the critical component of left ventricular mass related to coronary reserve. No significant correlation between the decrease in coronary vascular reserve and the presence of angina pectoris was demonstrated.     

Comparison of real-time contrast echocardiography and low-dose dobutamine stress echocardiography in predicting the left ventricular functional recovery in patients after acute myocardial infarction under different therapeutic intervention

BACKGROUND: Early prediction of left ventricular (LV) functional recovery after acute myocardial infarction (AMI) remains challenging. This prospective study aims to compare real-time myocardial contrast echocardiography (MCE) with low-dose dobutamine stress echocardiography (LDDSE) in predicting the LV functional recovery in patients after AMI who underwent different therapeutic interventions. METHODS: Ninety-two patients with AMI were divided into 3 groups: primary coronary intervention group (n=34), thrombolysis group (n=30) and conservative therapy group (n=28). MCE was performed 2.3+/-0.7 days after chest pain onset. LDDSE was done within 2 days of MCE study. Follow-up echocardiography was performed 4 months later. RESULTS: Patients treated by primary coronary intervention or thrombolysis had significantly lower regional perfusion score (0.65+/-0.53 vs. 1.01+/-0.49, p=0.008; 0.78+/-0.55 vs. 1.01+/-0.49, p=0.03), better contractile reserve (regional dobutamine Deltawall motion score -1.12+/-0.39 vs. -0.80+/-0.43, p=0.01; -0.99+/-0.50 vs. -0.80+/-0.43, p=0.08) and LV function recovery (regional Deltawall motion score -1.67+/-0.53 vs. -1.02+/-0.46, p=0.003; -1.42+/-0.58 vs. -1.02+/-0.46, p=0.03) than those of conservative therapy group. MCE and LDDSE showed good concordance for predicting LV functional recovery (kappa=0.63, p<0.001). Perfusion score index had a good correlation with LV functional recovery (r=-0.75, p<0.001). CONCLUSIONS: This study demonstrates that perfusion score index obtained from real-time MCE is comparable to LDDSE in predicting the LV functional recovery even under different therapeutic interventions. Revascularization results in better preservation of myocardial microvascular integrity, regional contractile reserve and LV functional recovery.     

Measurement of microvascular function in patients presenting with thrombolysis for ST elevation myocardial infarction,and PCI for non-ST elevation myocardial infarction

BackgroundIn this prospective study, we compared the invasive measures of microvascular function in two subsets: patients with pharmacoinvasive thrombolysis for STEMI, and patients undergoing percutaneous coronary intervention (PCI) for NSTEMI.MethodsThe study consisted of 17 patients with STEMI referred for cardiac catheterisation post thrombolysis, and 20 patients with NSTEMI. Coronary physiological indexes were measured in each patient before and after PCI.ResultsThe median pre-PCI index of microcirculatory function (IMR) at baseline was significantly higher in the STEMI group than the NSTEMI group (26 units vs. 15 units, p = 0.02). Following PCI, IMR decreased in both groups (STEMI 20 units vs. NSTEMI 14 units, p = 0.10). There was an inverse correlation between post PCI IMR and left ventricular ejection fraction (LVEF) (r = −0.52, p = 0.001). Furthermore, post PCI IMR was an independent predictor of index admission LVEF in the total population (β = −0.388, p = 0.02).ConclusionInvasive measures of microvascular function are inferior in a pharmacoinvasive STEMI group compared to a clinically stable NSTEMI group. In the STEMI population, the IMR following coronary intervention appears to predict LVEF.     

Non-invasive assessment of coronary flow reserve in idiopathic dilated cardiomyopathy: hemodynamic correlations.

BACKGROUND: Impaired vasodilator myocardial blood flow response has been observed in dilated cardiomyopathy (DCMP). However, the mechanisms responsible for this blunted response are not clear. In the present study, we investigated whether the blunted vasodilator flow response is related to indices of left ventricular performance in patients with idiopathic dilated cardiomyopathy. METHODS AND RESULTS: Eighteen DCMP patients and 12 healthy subjects (C) underwent transoesophageal echocardiography within 48 h from cardiac catheterization. Coronary flow velocity reserve (CFR) was measured in the proximal LAD as the ratio of the peak diastolic coronary flow velocity (Vd-M) after intravenous administration of adenosine to peak baseline diastolic flow velocity (Vd-R). Left ventricular (LV) mass index was positively correlated with baseline coronary diastolic velocity (r=0.415; p=0.043) and inversely correlated with coronary flow reserve (r=-0.570; p=0.003). The baseline coronary diastolic velocity was higher in DCMP vs C (56+/-13 cm/s vs 35+/-12 cm/s; p=0.04). In DCMP pts Vd-R positively correlated with end-diastolic wall stress (r=0.654; p=0.01). Vd increased in both C (96+/-32 cm/s; p<0.05 vs baseline) and DCMP patients (108+/-20 cm/s; p<0.01 vs baseline). The CFR was lower in DCMP patients vs C (1.93+/-0.78 vs 2.99+/-1.01; p=0.009). In DCMP pts CFR was negatively correlated with right atrial pressure (r=-0.595; p=0.015), LVEDP (r=-0.576; p=0.015), pulmonary capillary wedge pressure (PCWP: r=-0.772; p<0.001) and positively with ejection fraction (EF: r=0.683; p=0.003). CONCLUSION: Pts with DCMP have lower CFR compared to controls. This blunted CFR is due to higher baseline coronary flow and reflects higher wall stress. The close relation between CFR and EF, PCWP and LVEDP suggests that not only a higher baseline Vd but also compressive forces due to left ventricular dysfunction might be responsible for the observed blunted adenosine-mediated coronary vasodilation.     

Usefulness of diastolic deceleration time assessed by transthoracic Doppler measurement in the detection of sustained microvascular obstruction in STEMI patients treated by primary PTCA

Aims

To assess the value of coronary flow measurement by transthoracic Doppler technique in the detection of “no-reflow” phenomenon.

Methods

Fourteen patients with first anterior wall infarction treated by successful (TIMI3) primary percutaneous angioplasty and left descending coronary artery stenting were investigated. Myocardial perfusion following PCI was assessed by (i) ST-segment resolution, (ii) MRI-detected microvascular obstruction (early hypoenhancement), (iii) coronary flow pattern measurement by transthoracic Doppler technique.

Results

Sustained impairment of myocardial perfusion following PCI was observed in a large proportion of the cohort (36% by MRI, 43% by ST regression analysis). Patients with a diastolic deceleration time inferior to 482 ms had higher troponin and CK peak value, higher wall motion index score, lower ST resolution and lower LVEF assessed by MRI. The concordance of the three methods was 80%.

Conclusion

The measurement of diastolic deceleration time by transthoracic Doppler technique is a reliable technique to identify microvascular obstruction following PCI in acute anterior STEMI. A DDT inferior to 482 ms is associated with sustained “no-reflow” phenomenon.     

Relationship between coronary flow reserve and recovery of regional left ventricular function in patients with tako-tsubo-like transient left ventricular dysfunction

OBJECTIVES: This study assessed the relationship between coronary flow reserve and functional recovery of left ventricular wall motion in patients with tako-tsubo-like transient left ventricular dysfunction. METHODS: Coronary flow reserve was measured using the Doppler guide wire technique in the left descending coronary artery in nine consecutive patients (three men, six women, mean age 71 +/- 11 years) with tako-tsubo-like transient left ventricular dysfunction. Regional wall motion was analyzed to estimate anterior wall motion score index (anterior WMSI) by transthoracic echocardiography on admission and 3 weeks after the onset of symptoms. RESULTS: Anterior WMSI was 2.2 +/- 0.4 on admission and improved to 1.4 +/- 0.5 at 3 weeks later (p < 0.001). Coronary flow reserve on admission was not correlated to the anterior WMSI on admission (r = 0.19, p = 0.63). However, coronary flow reserve on admission was correlated to the improvement in anterior WMSI (r = 0.74, p = 0.02). CONCLUSIONS: Coronary microcirculation is damaged in acute phase of tako-tsubo-like transient left ventricular dysfunction. The severity of coronary microvascular dysfunction influences the degree of left ventricular wall motion recovery.     

Diastolic blood pressure as a determinant of Doppler left ventricular filling indexes in normotensive adolescents

Alterations in left ventricular filling can occur with aging and in patients with hypertension, ischemic heart disease, congestive and hypertrophic cardiomyopathy and congenital heart disease. This study examines the effects of blood pressure on left ventricular diastolic filling indexes measured by Doppler ultrasound technique in 47 young normotensive adolescents (mean age 13 years). Left ventricular filling was assessed by Doppler peak early and late diastolic transmitral flow velocities, early and late diastolic flow velocity integrals and early diastolic deceleration. Systolic blood pressure did not correlate with any of the Doppler filling indexes, although it was related to echocardiographic left ventricular mass (r = 0.44, p less than 0.005). Diastolic blood pressure did not correlate with left ventricular mass; however, it was inversely related to peak early diastolic flow velocity (r = -0.44, p less than 0.005), early diastolic flow velocity integral (r = -0.40, p less than 0.01) and early diastolic deceleration (r = -0.32, p less than 0.05). The ratio of late to early peak filling (A/E) was directly related to diastolic blood pressure (r = 0.48, p less than 0.001). Examination of electrocardiograms showed that there was a stronger correlation between A/E ratio and diastolic blood pressure (r = 0.63) in 22 subjects with bimodal P waves in lead V1 than in subjects with unimodal P waves (r = 0.45).(ABSTRACT TRUNCATED AT 250 WORDS)     

Intracoronary autologous bone marrow-derived mononuclear cell transplantation improves coronary collateral vessel formation and recruitment capacity in patients with ischemic cardiomyopathy: a combined hemodynamic and scintigraphic approach

This study investigated the effects of intracoronary autologous bone marrow-derived mononuclear cell (BMC) transplantation on coronary microcirculation. Fifteen patients with ischemic cardiomyopathy were treated by intracoronary infusion of BMCs via the patent infarct-related artery. The thermodilution-derived coronary flow reserve, index of microvascular resistance, pressure-derived collateral flow index, and coronary wedge pressure were measured at baseline and at 6 months. Successive balloon inflations during BMC transplantation were performed to observe the recruitment in pressure-derived collateral flow index and coronary wedge pressure, and the percentage changes between baseline and 6 months were calculated. The mean (SD) coronary flow reserve increased from 1.3 (0.4) to 2.1 (0.5), and the mean (SD) index of microvascular resistance decreased from 44.9 (24.4) to 21.2 (14.1) (P = .001 for both). The mean (SD) improvement in pressure-derived collateral flow index (from 0.14 [0.05] to 0.22 [0.08]) was also statistically significant (P = .001). Similarly, the percentage improvements in pressure-derived collateral flow index and coronary wedge pressure were statistically significant (P = .01 for both). The percentage improvement in perfusion assessed by single-photon emission computed tomography strongly correlated with the percentage changes in pressure-derived collateral flow index (r = 0.88, P = .001) and coronary wedge pressure (r = 0.69, P = .01). These results demonstrate for the first time (to our knowledge) that intracoronary autologous BMC transplantation improves coronary collateral vessel formation and recruitment capacity in human subjects.     

Impact of duration of ischemia on left ventricular diastolic properties following reperfusion for acute myocardial infarction

We sought the correlation between duration of myocardial ischemia and severe left ventricular (LV) diastolic dysfunction (restrictive filling pattern [RFP]) in patients with acute ST-elevation myocardial infarction (STEMI). Duration of ischemia determines infarct size and survival after STEMI. However, the impact of duration of ischemia on LV diastolic function has not been previously studied. Ninety-five consecutive patients with first-ever STEMI underwent transthoracic echocardiography 3 days after primary percutaneous coronary intervention (PCI). RFP was defined as a mitral inflow E/A ratio >2.0 and/or E-wave deceleration time <140 ms. Composite major adverse cardiovascular events (death, reinfarction, heart failure, revascularization) were determined at 12 months. Twenty patients (21%) had RFP on day 3. Symptom-to-reperfusion time in the RFP group was 413 ± 287 versus 252 ± 138 minutes in the non-RFP group (p = 0.014). Peak troponin T levels were higher in the RFP group (12.2 ± 8.4 vs 5.7 ± 3.6 ng/ml, p = 0.002). Logistic regression identified symptom-to-reperfusion time (hazard ratio 1.02, 95% confidence interval 1.01 to 1.03, p = 0.010) and infarct size by peak troponin T levels (hazard ratio 1.54, 95% confidence interval 1.14 to 2.10, p = 0.005) as independent predictors of RFP. Major adverse cardiovascular events occurred in 10 patients (50%) in the RFP group and 6 patients (8%) in the non-RFP group. On multivariate Cox proportional hazards analysis, RFP was an independent predictor of major adverse cardiovascular events at 12 months (hazard ratio 5.43, 95% confidence interval 1.52 to 19.39, p = 0.001). In conclusion, delayed reperfusion after STEMI was associated with severe LV diastolic dysfunction, which in turn independently predicted adverse long-term outcomes. LV diastolic dysfunction represents a significant pathophysiologic link among duration of myocardial ischemia, infarct size, and outcomes.     

Mechanisms of impaired coronary flow reserve in patients with aortic stenosis: transthoracic Doppler echocardiographic study

OBJECTIVES: Development of left ventricular hypertrophy in severe aortic stenosis is associated with coronary microcirculatory dysfunction, as demonstrated by impaired coronary flow reserve. Recently, coronary flow reserve can be assessed noninvasively by transthoracic Doppler echocardiography (TTDE). This study assessed the relationship between coronary flow reserve obtained by TTDE and the hemodynamic parameters and left ventricular mass index in patients with aortic stenosis. METHODS: Consecutive 29 patients (15 men, 14 women, mean age 72 +/- 11 years) with isolated mild to severe aortic stenosis were studied using TTDE to assess coronary flow reserve. Peak transvalvular pressure gradient across the aortic valve (peak AVG) and aortic valve area were measured by TTDE. Left ventricular mass index was measured by echocardiography. RESULTS: There were significant correlations between coronary flow reserve and peak AVG (r = -0.570, p = 0.001), left ventricular mass index (r = -0.620, p < 0.001), aortic valve area (r = 0.740, p < 0.001), and left ventricular rate pressure product (r = -0.660, p < 0.001). Multiple regression analysis showed that aortic valve area and peak AVG were independent factors for coronary flow reserve (p < 0.001, p = 0.048). CONCLUSIONS: Impairment of coronary flow reserve in patients with aortic stenosis is related to aortic valve area and peak AVG, rather than the degree of left ventricular hypertrophy.     

Clinical and functional determinants of coronary flow reserve in non-ischemic dilated cardiomyopathy: an echocardiographic study

Coronary flow reserve (CFR) is impaired in non-ischemic dilated cardiomyopathy (DCM). Mechanisms by which such impairment occurs are still unknown, but cofactors such as diastolic compressive force, left ventricular hypertrophy, and microvascular disease have been implied. In order to characterize the determinants of CFR in non-ischemic DCM, we evaluated 110 non-ischemic DCM patients (58 men; age=61+/-12 years) and 21 age- and gender-matched control patients (14 men; age=59+/-13 years) by transthoracic (n=88) or transesophageal (n=22) dipyridamole (0.84 mg/ kg in 10') stress echocardiography. All patients showed angiographically normal coronary arteries. Non-ischemic DCM patients had an ejection fraction <45% while control patients had normal left ventricular systolic function. CFR was assessed on LAD by pulsed Doppler as the ratio of maximal vasodilation (dipyridamole) to rest peak diastolic coronary flow velocity. Mean CFR value was 2.0+/-0.6 for DCM patients and 3.2+/-0.5 for controls (p<0.01). At individual non-ischemic DCM patient analysis, 46 patients had normal CFR> or =2 (Group 1) and 64 patients had abnormal CFR<2 (Group 2). On univariate analysis, CFR reduction correlated with NYHA functional class (r=-0.33, p=0.001), left ventricular ejection fraction ( r=0.23, p=0.02), end-systolic volume (r=-0.23, p=0.02), systolic pulmonary artery pressure (r=-0.42, p=0.0001), deceleration time (r=0.24, p=0.02). Logistic multiregression analysis showed that only NYHA functional class significantly and negatively correlated with CFR (odds ratio=0.9; 95% confidence intervals: 0.03-.35, p=0.0001). In patients with non-ischemic DCM, CFR is reduced but with substantial individual variability, only partially accounted for by level of systolic and diastolic dysfunction. The clinical functional class is the strongest predictor of CFR reduction in these patients, with lowest flow reserve found in more advanced NYHA class.     

Comparison of usefulness of left ventricular diastolic versus systolic function as a predictor of outcome following primary percutaneous coronary angioplasty for acute myocardial infarction

Left ventricular (LV) diastolic function is an important predictor of morbidity and mortality after acute myocardial infarction (AMI). We evaluated the role of diastolic function in predicting in-hospital events and LV ejection fraction (EF) 6 months after a first AMI that was treated with primary percutaneous coronary intervention (PCI). We prospectively enrolled 59 consecutive patients who were 60 +/- 15 years of age (48 men), presented at our institution with their first AMI, and were treated with primary PCI. Patients underwent 2-dimensional and Doppler echocardiography, including tissue Doppler imaging of 6 basal mitral annular regions within 24 hours after primary PCI and were followed until discharge. Clinical and echocardiographic variables at index AMI were compared with a combined end point of cardiac death, ventricular tachycardia, congestive heart failure, or emergency in-hospital surgical revascularization. Follow-up echocardiographic assessment was performed at 6 months in 24 patients. During hospitalization, 3 patients died, 7 developed congestive heart failure, 4 had ventricular tachycardia, and 1 required emergency surgical revascularization. Stepwise logistic regression analysis showed the ratio of early mitral inflow diastolic filling wave (E) to peak early diastolic velocity of non-infarct-related mitral annulus (p < 0.01) (E') and mitral inflow E-wave deceleration time (p < 0.02) to be independent predictors of in-hospital cardiac events (generalized R2 = 0.66). In a stepwise multiple linear regression model, independent predictors of follow-up LVEF were mitral inflow deceleration time (R2 = 0.39, p = 0.002), baseline LVEF (R2 = 0.54, p < 0.02), and mitral inflow peak early velocity/mitral annular peak early velocity (or E/E') of infarct annulus (R2 = 0.66, p = 0.02). In conclusion, in patients who are treated with primary PCI for a first AMI, E/E' velocity ratio and mitral inflow E-wave deceleration time are strong predictors of in-hospital cardiac events and of LVEF at 6-month follow-up.     

Intracoronary Hemodynamic Effects of Pressure‐Controlled Intermittent Coronary Sinus Occlusion (PICSO): Results from the First‐In‐Man Prepare PICSO Study

Background: Myocardial reperfusion is frequently suboptimal after ST‐segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (PCI). Using a balloon‐tipped catheter positioned in the coronary sinus (CS), pressure‐controlled intermittent coronary sinus occlusion (PICSO) results in an intermittent obstruction of coronary venous outflow of the left anterior descending artery (LAD), and may improve myocardial perfusion by augmenting redistribution of blood to the border zone of ischemic myocardium. We sought to document the intracoronary hemodynamic effects of PICSO during PCI. Methods: We included 15 patients with stable angina scheduled for PCI of the LAD. Balloon occlusion of the LAD was performed twice, once with and once without PICSO and lasting maximally 3 minutes each, to document the effect of PICSO on CS pressure and LAD wedge pressure. Results: Catheter delivery was successful in all patients. The study protocol could not be conducted in 5 patients due to initial calibration difficulties (n = 3), a pressure wire problem (n = 1), and a vagal response at the start of the procedure (n = 1). In the remaining 10 patients, CS occlusion caused a marked increase in mean CS pressure (4.1 ± 7.3 mmHg vs. 22.0 ± 12.6 mmHg; P < 0.001) and CS pulse pressure (4.3 ± 0.8 mmHg vs. 36.1 ± 6.3 mmHg; P < 0.001). Concomitantly, mean distal LAD wedge pressure and wedge pulse pressure increased (32.4 ± 12.2 mmHg vs. 35.5 ± 12.6 mmHg; P < 0.001 and 39.1 ± 27.2 mmHg vs. 45.9 ± 26.0 mmHg; P < 0.001, respectively). At 30 day follow‐up, no device‐related events occurred. Conclusions: PICSO safely augments CS pressure, thereby increasing LAD coronary wedge pressure. These findings support further evaluation of PICSO in the setting of STEMI. (J Interven Cardiol 2012;25:549–556)     

Relation of aspirin resistance to coronary flow reserve in patients undergoing elective percutaneous coronary intervention

Previous studies have shown that more complete platelet inhibition improves the coronary flow reserve (CFR), a measure of microvascular integrity, in patients undergoing percutaneous coronary intervention (PCI). We hypothesized that patients with aspirin resistance would have impaired CFR after elective PCI. We used VerifyNow Aspirin to determine the response to aspirin in 117 consecutive patients who underwent elective single-lesion PCI. The assay results are expressed quantitatively in Aspirin Reaction Units based on the degree of platelet aggregation. All patients received a 300-mg loading dose of clopidogrel >12 hours before and a 75-mg maintenance dose the morning of PCI. CFR was estimated using the Thrombolysis In Myocardial Infarction frame count method. Of the 117 patients, 22 (18.8%) were aspirin resistant. The clinical, angiographic, and procedural characteristics of the aspirin-sensitive and -resistant patients were balanced. All patients underwent successful PCI with <50% residual diameter stenosis and Thrombolysis In Myocardial Infarction grade 3 flow after PCI. Aspirin-resistant patients had a lower CFR than the aspirin-sensitive patients (1.42 +/- 0.35 vs 1.80 +/- 0.64, p = 0.018). Univariate correlates of CFR included the Aspirin Reaction Unit (r = -0.227, p = 0.014) and post-PCI creatine kinase-MB elevation (p = 0.048). Multivariate linear regression analysis revealed the Aspirin Reaction Unit to be the only independent determinant of CFR after PCI (r2 = 0.051, p = 0.014). Thus, aspirin resistance was associated with impaired CFR in patients who underwent elective PCI, implicating insufficient aspirin-induced platelet inhibition as a cause of microvascular dysfunction by distal atherothrombotic embolization and/or spasm.