Search

Background: To consider hemodynamic assessment of myocardial bridging (MB) adequate, it is believed that inotropic stimulation with dobutamine should be estimated because its dynamic nature depends on the degree of extravascular coronary compression. This study evaluated comparative assessment of hemodynamic relevance of MB using coronary flow velocity reserve (CFVR) measurements by transthoracic Doppler echocardiography (TTDE) with vasodilatative and inotropic challenges., Methods: This prospective study included forty-four patients with angiographic evidence of isolated MB of the left anterior descending coronary artery (LAD) and systolic compression of ≥50% diameter stenosis. All patients were evaluated by exercise stress-echocardiography (ExSE) test for signs of myocardial ischemia, and CFVR of the distal segment of LAD during iv.infusion of adenosine (ADO:140μg/kg/min) and iv.infusion of dobutamine (DOB:10-40μg/kg/min), separately., Results: Exercise-SE was positive for myocardial ischemia in 8/44 (18%) of patients. CFVR during ADO was significantly higher than CFVR during peak DOB (2.85±0.68 vs. 2.44±0.48, p=0.002). CFVR during peak DOB was significantly lower in SE-positive group in comparison to SE-negative group (2.01±0.16 vs. 2.54±0.47, p<0.001), but not for ADO (2.47±0.51 vs. 2.89±0.70, p=0.168), respectively. Multivariable logistic analysis showed that CFVR peak DOB was the most significant predictor of functional significant MB (OR 0.011, 95%CI: 0.001-0.507, p=0.021). Receiver-operating characteristic curves have shown that TTDE-CFVR obtained by high-dose of dobutamine infusion is better than those by adenosine regarding to functional status of MB (AUC 0.861, p=0.004; AUC 0.674, p=0.179, respectively)., Conclusions: Non-invasive CFVR measurement by TTDE during inotropic stimulation, in comparison to vasodilation, provides more reliable functional evaluation of MB., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Background and Purpose: To analyze plasma adiponectin kinetics in patients with ST-segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (pPCI) and its association with coronary flow reserve (CFR), an index of coronary microcirculatory function., Methods: A total of 96 consecutive patients with the first anterior STEMI treated by pPCI without heart failure were included. CFR was assessed on the 7th day after pPCI. Plasma adiponectin was measured on admission before pPCI, and on the 2nd and 7th day after pPCI., Results: Adiponectin concentration was the highest on admission, declined to the lowest level on the 2nd day, and rose on the 7th day remaining below admission values. Impaired coronary microcirculatory function (CFR<2) was observed in 41% of the patients. Adiponectin concentrations significantly positively correlated with CFR, and the strongest correlation was with the 2nd day adiponectin (r=0.489, p<0.001). In multivariate models, adiponectin concentrations were independent predictors of impaired CFR [on admission: odds ratio (OR) 0.175, confidence interval (CI): 0.047-0.654, p=0.010; 2nd day: OR 0.146, 95% CI: 0.044-0.485, p=0.002; 7th day: OR 0.198, CI: 0.064-0.611, p=0.005]. The best power to predict impaired CFR was the 2nd day adiponectin. Delta values of adiponectin (differences between adiponectin concentrations) did not correlate with CFR., Conclusions: In patients with the first anterior STEMI treated by pPCI plasma adiponectin concentrations before and after pPCI are strongly associated with CFR. Our results support the hypothesis that low adiponectin, especially during the early post-pPCI period, carries the risk for impaired coronary microcirculatory function in STEMI patients., (Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.)

Background: Insulin resistance (IR) assessed by the Homeostatic Model Assessment (HOMA) index in the acute phase of myocardial infarction in non-diabetic patients was recently established as an independent predictor of intrahospital mortality. In this study we postulated that acute IR is a dynamic phenomenon associated with the development of myocardial and microvascular injury and larger final infarct size in patients with ST-segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (pPCI)., Methods: In 104 consecutive patients with the first anterior STEMI without diabetes, the HOMA index was determined on the 2nd and 7th day after pPCI. Worst-lead residual ST-segment elevation (ST-E) on postprocedural ECG, coronary flow reserve (CFR) determined by transthoracic Doppler echocardiography on the 2nd day after pPCI and fixed perfusion defect on single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) determined six weeks after pPCI were analyzed according to HOMA indices., Results: IR was present in 55 % and 58 % of patients on day 2 and day 7, respectively. Incomplete post-procedural ST-E resolution was more frequent in patients with IR compared to patients without IR, both on day 2 (p = 0.001) and day 7 (p < 0.001). The HOMA index on day 7 correlated with SPECT-MPI perfusion defect (r = 0.331), whereas both HOMA indices correlated well with CFR (r = -0.331 to -0.386) (p < 0.01 for all). In multivariable backward logistic regression analysis adjusted for significant univariate predictors and potential confounding variables, IR on day 2 was an independent predictor of residual ST-E ≥ 2 mm (OR 11.70, 95% CI 2.46-55.51, p = 0.002) and CFR < 2 (OR = 5.98, 95% CI 1.88-19.03, p = 0.002), whereas IR on day 7 was an independent predictor of SPECT-MPI perfusion defect > 20% (OR 11.37, 95% CI 1.34-96.21, p = 0.026)., Conclusion: IR assessed by the HOMA index during the acute phase of the first anterior STEMI in patients without diabetes treated by pPCI is independently associated with poorer myocardial reperfusion, impaired coronary microcirculatory function and potentially with larger final infarct size.

Background: Patients in chronic phase of myocardial infarction (MI) have decreased coronary flow reserve (CFR) in infarct related artery (IRA) that is proportional to the extent of microvascular/myocardial damage. We proposed a novel model for the assessment of microvascular damage and infarct size using Doppler echocardiography evaluation of CFRs of the IRA (LAD) and reference artery (RCA)., Methods: Our study included 34 consecutive patients (28 men, mean age 50 ± 11 years) with first anterior STEMI and single vessel disease successfully treated with primary PCI. All patients underwent SPECT MPI for the assessment of infarct size (expressed as a percentage of myocardium with fixed perfusion abnormalities) and CFR evaluation of LAD and RCA. CFR derived percentage of microvascular damage (CFR PMD) was calculated as: CFR PMD=(CFR RCA-CFR LAD)/(CFR RCA-1)×100 (%)., Results: CFR PMD correlated significantly with all parameters evaluating the severity of myocardial damage including: peak CK activity (r=0.632, p<0.001), WMSI (r=0.857, p<0.001), ejection fraction (r=-0.820, p<0.001), left ventricular end diastolic (r=0.757, p<0.001) and end systolic volume (r=0.794, p<0.001). Most importantly, CFR PMD (22 ± 17%) correlated significantly with infarct size by SPECT MPI (21 ± 17%) (r=0.874, p<0.001)., Conclusions: CFR PMD derived from the proposed model was significantly related to echocardiographic and enzymatic parameters of infarct size, as well as to myocardial damage assessed by SPECT MPI in patients with successfully reperfused first anterior STEMI., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Background: In patients with previous myocardial infarction (MI), assessment of myocardial viability and physiological significance of coronary artery stenoses are essential for appropriate guidance of revascularization. The aim of the study was to evaluate the relation between fractional flow reserve (FFR) and myocardial viability as assessed by gated SPECT MIBI perfusion scintigraphy in patients with previous MI undergoing elective PCI., Methods: The study population consisted of 26 patients (mean age 55 ± 7 years; 21 male) with a previous MI and a significant coronary stenosis in a single infarct-related coronary vessel for which PCI was being performed. In all patients, FFR was evaluated before and immediately after PCI. SPECT imaging was done before and 3 ± 1 months after PCI. A region representing the MI was considered viable if MIBI uptake was ≥55% of the normal region. Improvement in perfusion after revascularization was considered achieved if perfusion abnormalities decreased by 5% or more and there was a decrease in segmental score of ≥1 in three segments in PCI-related vascular territory., Results: Extent of perfusion abnormalities decreased from 32 ± 16% to 27 ± 19% after PCI (P < .001). In patients with myocardial viability in comparison to patients with no viability, there was significant difference in FFR before PCI (.57 ± .14 vs .76 ± .12, P = .002), despite almost the same values of diameter stenosis of infarct-related artery (63 ± 8% vs 64 ± 3%, respectively, P = .572). In addition, FFR prior to PCI was related to improvement in perfusion abnormalities after revascularization (P = .047), as well as with peak activity of creatine-kinase measured during previous MI (r = .56, P = .005)., Conclusion: Lower values of FFR before angioplasty are associated with myocardial viability and functional improvement as assessed by SPECT perfusion scintigraphy.

Evaluation of coronary pressures during angioplasty may functionally quantify collateral circulation. The aim of the study was to evaluate the relation between the amount of collateral circulation and development of myocardial ischemia during balloon occlusion, anatomic degree of collaterals, and functional improvement of myocardium. Study population consisted of 31 pts (mean age 53 +/- 7 years; 25 male) with previous myocardial infarction and significant one-vessel stenosis undergoing angioplasty. Collateral circulation was calculated as the ratio between distal coronary pressure during balloon occlusion (P(w)) and aortic pressure (P(a)). Angiographic appearance of collaterals was evaluated by Rentrop classification. Patients were evaluated by echo for functional improvement of myocardium in the follow-up period. Mean P(w)/P(a) was 0.24 +/- 0.10 (range of 0.07-0.51). Rentrop grade 0 of collaterals was present in 16 patients (52%), grade 1 in11 patients (35%), and grade 2 in 4 patients (13%). A mild correlation between angio and hemodynamic evaluation of collaterals was observed (r = 0.38, P = 0.035). In patients without ECG changes during angioplasty (21 pts, 68%), P(w)/P(a) was significantly higher in comparison to patients with ECG changes (0.28 +/- 0.09 vs. 0.15 +/- 0.06, P < 0.001; area under the curve 0.93). In patients with myocardial functional improvement during follow-up (21 pts, 68%), P(w)/P(a) was significantly higher than in the patients without echo improvement (0.26 +/- 0.10 vs. 0.18 +/- 0.08, P = 0.035). The amount of recruitable collaterals is not negligible even in the patients with no angio visible collaterals. Low values of P(w)/P(a) are associated with ECG changes during balloon occlusion. Higher P(w)/P(a) was associated with better functional improvement of myocardium.