Response of the left anterior descending coronary artery to acetylcholine in patients with chest pain and angiographically normal coronary arteries

Because atherosclerotic plaque burden affects the likelihood of plaque rupture, it is important to determine the presence and extent of atherosclerotic plaque. We hypothesized that endothelial dysfunction becomes more prominent with development of atherosclerotic plaque; therefore, we examined the relation between coronary endothelial dysfunction and the presence of atherosclerotic plaque. In 36 patients with normal coronary arteries, acetylcholine (ACh; 3 and 30 μg/min) and nitroglycerin were infused into the left coronary ostium, and the diameter of the left anterior descending (LAD) coronary artery was quantitatively measured in response to each drug. The plaque burden was measured in the same segment using intravascular ultrasonography. The plaque burden was 31.2 ± 2.1% and correlated inversely with changes in coronary diameter induced by 3 μg/min of ACh (r = −0.754, p <0.0001), 30 μg/min of ACh (r = −0.552, P = 0.0005), and nitroglycerin (r = −0.531, P = 0.0009). Multivariate regression analysis showed that the change in coronary diameter induced by 3 μg/min of ACh was associated with plaque burden, independent of the effects of nitroglycerin-induced dilation. Receiver-operating characteristics analysis demonstrated that a cut-off value for the change in coronary diameter induced by 3 μg/min of ACh for predicting a plaque burden of>30% was 0%, with a sensitivity of 0.82 and a specificity of 0.95. These findings suggest that coronary endothelial dysfunction is correlated with atherosclerotic plaque burden, indicating that atherosclerotic plaque may be detected based on coronary endothelial function as assessed by low-dose ACh infusion.     

Glycated albumin is a better indicator for glucose excursion than glycated hemoglobin in type 1 and type 2 diabetes

To determine the impact of blood glucose profile, involving fluctuation and excursion of blood glucose levels, on glycated proteins, we evaluated the association among the daily profile of blood glucose, and glycated albumin (GA) and HbA1c levels in patients with type 1 diabetes (n = 93) and type 2 diabetes (n = 75). GA levels were strongly correlated with HbA1c levels in type 1 (r = 0.85, P<0.0001) and type 2 diabetes (r = 0.61, P<0.0001), respectively. HbA1c levels were similar between patients with type 1 and type 2 diabetes, while GA levels were significantly higher in type 1 diabetes. Thus the ratio of GA levels to HbA1c levels was significantly higher in type 1 diabetes than that in type 2 diabetes (3.32 0.36 vs. 2.89 0.44, p<0.001). The degrees of GA levels and HbA1c levels correlated with maximum and mean blood glucose levels in patients with type 1 and type 2 diabetes. Stepwise multivariate analysis revealed that GA levels independently correlated with maximum blood glucose levels in type 1 diabetes (F = 43.34, P<0.001) and type 2 diabetes (F = 41.57, P<0.001). HbA1c levels also independently correlated with maximum blood glucose levels in type 1 diabetes (F = 34.78, P<0.001), as well as being correlated with mean blood glucose levels in type 2 diabetes (F = 11.28, P<0.001). In summary, GA could be a better marker for glycemic control than glycated hemoglobin in diabetic patients, especially for evaluating glycemic excursion, which is considered to be a major cause of diabetic angiopathy.     

Effect of preintervention remodeling type on subsequent coronary artery behavior after directional atherectomy

To evaluate the influence of preintervention remodeling on subsequent vessel behavior after directional coronary atherectomy (DCA) under intravascular ultrasound (IVUS) guidance, serial (before and after DCA and at 6-month follow-up) IVUS data were analyzed for 246 lesions that were classified into 2 categories: positive remodeling (PR) in 77 lesions versus intermediate or negative remodeling in 169 lesions. Although the 2 groups had similar baseline characteristics, IVUS data showed that the PR group had a greater acute lumen area (LA) gain without an increased late LA loss, resulting in a greater net (acute plus late) LA gain and follow-up LA. This suggests that IVUS-guided DCA may neutralize the negative impact of preintervention PR on late vessel patency.     

Contrast-enhanced multidetector-row computed tomography vs. time-resolved magnetic resonance angiography vs. contrast-enhanced perfusion MRI: Assessment of treatment response by patients with inoperable chronic thromboembolic pulmonary hypertension

Purpose:

To compare therapeutic effect assessment capability of multidetector‐row computed tomography (MDCT), magnetic resonance angiography (MRA), and dynamic perfusion MRI for chronic thromboembolic pulmonary hypertension (CTEPH) patients.

Materials and Methods:

Twenty‐four consecutive CTEPH patients treated with conventional therapy underwent pre‐ and posttherapeutic MDCT, MRA, dynamic perfusion MRI, 6‐minute walk distance (6‐MWD), cardiac ultrasound (US), and right heart catheterization. According to therapeutic results, all patients were divided into response (n = 13) and nonresponse (n = 11) groups. CTEPH indexes for MDCT (CTEPH_CT) and MRA (CTEPH_MRA) were calculated on the basis of embolic burden. Pulmonary perfusion parameter maps were generated from all perfusion MR data, followed by determination of improvements in mean perfusion parameter at regions of interest (ROIs) for each patient. Receiver operating characteristic (ROC)‐based positive tests were performed to determine the feasible threshold values for distinguishing two groups. Finally, diagnostic capabilities were compared by means of McNemar's test.

Results:

When feasible threshold values adapted, specificity (90.9 〈10/11〉%, P < 0.05) and accuracy (95.8 〈23/24〉%, P < 0.05) for improvement in pulmonary blood flow were significantly higher than those for CTEPH_CTA (specificity: 36.4 〈4/11〉%, accuracy: 70.8 〈17/24〉%).

Conclusion:

Dynamic perfusion MRI has better capability for assessment of therapeutic effect on CTEPH patients than does MDCT. J. Magn. Reson. Imaging 2012;36:612–623. © 2012 Wiley Periodicals, Inc.