Optimum Hypoglycemic Therapy can Improve Coronary Flow Velocity Reserve in Diabetic Patients-Demonstration by Transthoracic Doppler Echocardiography-

Effects of non-supervised low intensity aerobic excise training on the microvascular endothelial function of patients with type 1 diabetes: a non-pharmacological interventional study

Background

The aim of the present study was to evaluate changes in microvascular density and reactivity in patients with type 1 diabetes (T1D) resulting from low intensity chronic exercise training.

Methods

This study included 22 (34 ± 7 years) consecutive outpatients with T1D and disease duration > 6 years. We used intravital video-microscopy to measure basal skin capillary density and capillary recruitment using post-occlusive reactive hyperemia (PORH) in the dorsum of the fingers. Endothelium-dependent and -independent vasodilation of the skin microcirculation was evaluated in the forearm with a laser Doppler flow monitoring (LDF) system in combination with acetylcholine and sodium nitroprusside iontophoresis, PORH and local thermal hyperemia.

Results

The basal mean capillary density (MCD) after exercise training was significantly higher than before exercise (134 ± 25 vs. 119 ± 19 capillaries/mm², respectively; P = 0.0013). MCD during PORH was also higher after exercise (140 ± 26 vs. 121 ± 24 capillaries/mm², respectively; P < 0.0001). Endothelium-dependent capillary recruitment during PORH was also significantly higher after exercise (140 ± 26 vs. 134 ± 25 capillaries/mm², respectively; P < 0.0012). There were no significant changes in skin microvascular reactivity after exercise as investigated using LDF.

Conclusions

Our results showed that low intensity aerobic exercise, performed four times per week for 12 weeks by patients with T1D, induces significant increases in microvascular density and endothelial-dependent capillary reactivity.

Trial registration

ClinicalTrials.gov NCT02441504. Registered 7 May 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0191-9) contains supplementary material, which is available to authorized users.

Insulin resistance and acute glucose changes determine arterial elastic properties and coronary flow reserve in dysglycaemic and first-degree relatives of diabetic patients

BACKGROUND

Insulin resistance is linked to endothelial dysfunction. We investigated whether first-degree relatives of type-2 diabetes patients (FDR) present differences in vascular function at baseline and during postprandial hyperglycemia compared to dysglycaemic or normoglycaemic subjects.

METHODS

We studied 40 FDR with normal oral glucose test (OGTT), 40 subjects with abnormal OGTT (dysglycaemic) and 20 subjects with normal OGTT without parental history of diabetes (normoglycaemic) with similar clinical characteristics. Glucose, insulin, pulse wave velocity (PWV), central systolic blood pressure (cSBP) and augmentation index (AI) were measured at 0, 30, 60, 90 and 120min during OGTT. Coronary flow reserve (CFR) was assessed using Doppler echocardiography at 0 and 120min after OGTT. Insulin sensitivity was evaluated using Matsuda and insulin sensitivity index (ISI).

RESULTS

FDR and dysglycaemics had higher fasting insulin, reduced ISI, Matsuda index as well as reduced CFR (2.54 ± 0.5 vs. 2.45 ± 0.3 vs. 2.74 ± 0.5), increased PWV, (8.9 ± 1.1 vs. 10.3 ± 2.4vs. 8.0 ± 1.5 m/sec), AI (23.8 ± 13.6 vs. 26.5 ± 14.4vs.17.7  ±  14%) and cSBP than normoglycaemics (p < 0.05 for all comparisons). During OGTT, AI was similarly reduced in both normoglycaemic and FDR (p < 0.05) at peak insulin levels (60 min) though FDR had 2-fold higher insulin than normoglycaemics. AI was increased in dysglycaemics after peak glucose levels, at 120 min (p < 0.05). CFR was reduced by 10% and 15% at 120min in FDR and dysglycaemic respectively, while remained unchanged in normoglycaemics (p < 0.05). The percent reduction of CFR was related with the percent increase of glucose levels, ISI and Matsuda index(p < 0.05).

CONCLUSION

First-degree relatives and dysglycaemic patients have impaired arterial and coronary microcirculatory function. Insulin resistance determines acute vascular responses during postprandial hyperglycemia. CLINICALTRIALS.

GOV IDENTIFIER

NCT02244736.

Coronary Microvascular Function and Beyond: The Crosstalk between Hormones, Cytokines, and Neurotransmitters

Beyond its hemodynamic function, the heart also acts as a neuroendocrine and immunoregulatory organ. A dynamic communication between the heart and other organs takes place constantly to maintain cardiovascular homeostasis. The current understanding highlights the importance of the endocrine, immune, and nervous factors to fine-tune the crosstalk of the cardiovascular system with the entire body. Once disrupted, this complex interorgan communication may promote the onset and the progression of cardiovascular diseases. Thus, expanding our knowledge on how these factors influence the cardiovascular system can lead to novel therapeutic strategies to improve patient care. In the present paper, we review novel concepts on the role of endocrine, immune, and nervous factors in the modulation of microvascular coronary function.

Prognostic value of coronary flow reserve on long-term cardiovascular outcomes in patients with chronic kidney disease

Cardiovascular (CV) diseases and chronic kidney disease (CKD) have common predisposing factors that subsequently cause microvascular dysfunction. In the absence of obstructive coronary artery disease, coronary flow reserve (CFR) represents the status of coronary microcirculation. This study aimed to investigate the prognostic importance of impaired CFR, as a marker of microvascular dysfunction, on long-term CV outcomes in patients with CKD. This study consisted of 139 patients with an estimated glomerular filtration rate of <60 ml/min/1.73 m(2) who had no obstructive narrowing of the left anterior descending artery. Transthoracic Doppler echocardiography was used to measure CFR in the left anterior descending artery. During the follow-up period (3.3 ± 1.6 years), CV events occurred in 26 patients (18.7%). Multivariate analysis that included CFR as a continuous value identified a serum level of C-reactive protein (hazard ratio 1.41, p = 0.03) and a value of CFR (hazard ratio 0.21, p = 0.009) as determinants for CV events, independent of traditional CV risk factors. Patients with a CFR of <2.0 had worse CV outcomes compared with those with a CFR of ≥2.0 (p <0.001). In conclusion, transthoracic Doppler echocardiographically derived CFR was useful for the risk stratification of CV outcomes in patients with CKD. The presence of microvascular dysfunction may play an important role in the association between CKD and future CV events.

Noninvasive assessment of coronary vasodilation using cardiovascular magnetic resonance in patients at high risk for coronary artery disease

BACKGROUND

Impaired coronary vasodilation to both endothelial-dependent and endothelial-independent stimuli have been associated with atherosclerosis. Direct measurement of coronary vasodilation using x-ray angiography or intravascular ultrasound is invasive and, thus, not appropriate for asymptomatic patients or for serial follow-up. In this study, high-resolution coronary cardiovascular magnetic resonance (CMR) was used to investigate the vasodilatory response to nitroglycerine (NTG) of asymptomatic patients at high risk for CAD.

METHODS

A total of 46 asymptomatic subjects were studied: 13 high-risk patients [8 with diabetes mellitus (DM), 5 with end stage renal disease (ESRD)] and 33 age-matched controls. Long-axis and cross-sectional coronary artery images were acquired pre- and 5 minutes post-sublingual NTG using a sub-mm-resolution multi-slice spiral coronary CMR sequence. Coronary cross sectional area (CSA) was measured on pre- and post-NTG images and % coronary vasodilation was calculated.

RESULTS

Patients with DM and ESRD had impaired coronary vasodilation to NTG compared to age-matched controls (17.8 +/- 7.3% vs. 25.6 +/- 7.1%, p = 0.002). This remained significant for ESRD patients alone (14.8 +/- 7.7% vs. 25.6 +/- 7.1%; p = 0.003) and for DM patients alone (19.8 +/- 6.3% vs. 25.6 +/- 7.1%; p = 0.049), with a non-significant trend toward greater impairment in the ESRD vs. DM patients (14.8 +/- 7.7% vs. 19.8 +/- 6.3%; p = 0.23).

CONCLUSION

Noninvasive coronary CMR demonstrates impairment of coronary vasodilation to NTG in high-risk patients with DM and ESRD. This may provide a functional indicator of subclinical atherosclerosis and warrants clinical follow up to determine prognostic significance.

Non-invasive assessment of coronary flow and coronary flow reserve by transthoracic Doppler echocardiography: a magic tool for the real world

Transthoracic Doppler echocardiography, introduced in the echo-lab in recent last years, to measure coronary flow and coronary flow reserve, is a very attractive tool, totally non-invasive, and easily available at bedside. This review summarizes the actual possibilities of this tool, its multiple potential clinical applications and diagnostic insights, and its arising prognosis value, in coronary artery disease as in various settings affecting the coronary microcirculation.

Close relationship between sympathetic activation and coronary microvascular dysfunction during acute hyperglycemia in subjects with atherosclerotic risk factors

BACKGROUND

The effect of acute hyperglycemia (AHG) during the oral glucose tolerance test (OGTT) on coronary microvascular function was evaluated, as well as the associations among the changes in coronary microvascular function, oxidative stress, and sympathetic tone.

METHODS AND RESULTS

Transthoracic Doppler echocardiography and OGTT were performed in 24 subjects with atherosclerotic risk factors (61+/-9 years). The coronary flow velocity before and during the infusion of adenosine (CFV(hyp)), plasma levels of thiobarbituric acid-reactive substances (TBARS), and the low-frequency/high-frequency power (LF/HF) ratio yielded by power spectral analysis of heart rate variability were measured before and at 1 h during 75-g OGTT. AHG significantly decreased the CFV(hyp), and increased the TBARS and LF/HF. Multiple linear regression analysis revealed that the percent changes in the CFV(hyp) were significantly associated with the percent changes in the LF/HF ratio (beta=-0.43, p<0.05).

CONCLUSION

In subjects with atherosclerotic risk factors who may be considered likely to have atherosclerotic arterial damage, AHG seems to induce concomitant coronary microvascular dysfunction, increased oxidative stress, and sympathetic activation. Coronary microvascular dysfunction, therefore, appears to be closely related to sympathetic activation.

Prognostic Value of Blood Glucose in Patients With Cardiogenic Shock

BACKGROUND

Although an elevated blood glucose has prognostic value in cardiovascular disease, few data are available regarding its prognostic value for patients across the spectrum of cardiogenic shock.

METHOD AND RESULTS

A total of 81 patients with cardiogenic shock whose blood glucose and adrenaline were measured on arrival at the emergency room (ER) were enrolled in this prospective study. The primary endpoint was death from any cause in hospital. The rate of death was 12.3% (10/81), and the glucose level was lower among patients who were discharged alive than among those who died (8.7+/-3.7 mmol/L vs 13.8+/-6.7 mmol/L, p<0.001). The unadjusted rate of death increased in a stepwise fashion among patients in increasing quartiles of glucose level (p<0.05). The blood glucose level of 9.2 mmol/L had the highest combined sensitivity and specificity for the identification of death. In the multiple logistic-regression analysis for the primary outcome, the adjusted odd ratio for a glucose level of 9.2 mmol/L or more was 5.8 (95% confidence interval, 1.0-32.8, p=0.047). There was a significant positive correlation between the glucose and adrenaline levels (R=0.726, p<0.0001).

CONCLUSION

The measurement of blood glucose level on ER arrival provides predictive information for use in risk stratification across the spectrum of cardiac emergencies complicated by cardiogenic shock.

Effects of glucose abnormalities on in-hospital outcome after coronary intervention for acute myocardial infarction

BACKGROUND

The effects of glucose abnormalities on outcomes after percutaneous coronary intervention (PCI) remain unclear. We examined the association between glucose abnormalities and in-hospital outcome in patients undergoing PCI for acute myocardial infarction (AMI).

METHODS AND RESULTS

A total of 849 patients with AMI who were admitted within 12 h after symptom onset and underwent emergency PCI were classified according to the presence or absence of admission hyperglycemia, defined as a blood glucose level on admission of >11 mmol/L and whether they had a history of diabetes mellitus: group 1 (n = 504), non-diabetic patients without admission hyperglycemia; group 2 (n = 111), diabetic patients without admission hyperglycemia; group 3 (n = 87), non-diabetic patients with admission hyperglycemia; and group 4 (n = 147), diabetic patients with admission hyperglycemia. Among groups 1, 2, 3 and 4, in-hospital mortality was 2.6, 2.7, 11.5 and 8.8%, respectively (p < 0.01). Multivariate analysis showed that compared with group 1 patients, the odds ratio (95%confidence interval) for in-hospital mortality among those in groups 2, 3, and 4 were 0.80 (0.24-2.60, p = 0.708), 2.29 (1.10-5.49, p = 0.039), and 2.14 (1.14-4.69, p = 0.048), respectively.

CONCLUSIONS

In-patients undergoing PCI for AMI, admission hyperglycemia, irrespective of the presence or absence of diabetes, is associated with increased in-hospital mortality, whereas diabetes without admission hyperglycemia is not.

Effect of one or more co-morbid conditions on diagnostic accuracy of coronary flow velocity reserve for detecting significant left anterior descending coronary stenosis

OBJECTIVE

To determine the effect of one or multiple co-morbid conditions on the diagnostic accuracy of coronary flow velocity reserve (CFVR) in a heterogeneous patient population.

METHODS

CFVR was measured in the left anterior descending coronary artery (LAD) by transthoracic Doppler echocardiography (TTDE) in 318 consecutive patients before elective coronary angiography. CFVR was calculated as the average peak diastolic velocity during intravenous ATP infusion divided by baseline flow velocity. All patients underwent coronary angiography within 48 hours. Significant LAD stenosis was defined as > 50% luminal narrowing. Diagnostic accuracy of CFVR was analysed according to the type and number of risk factors that may adversely affect microvascular function.

RESULTS

CFVR was measured in 309 patients, of whom 105 were found to have significant LAD stenosis based on coronary angiography. CFVR < 2.0 had a sensitivity of 86% and a specificity of 77% for predicting significant LAD stenosis. Left ventricular hypertrophy (LVH) was the only factor that significantly lowered diagnostic accuracy (61% with LVH v 84% without LVH, p < 0.001). Diagnostic accuracy was not affected by increasing number of risk factors.

CONCLUSIONS

The diagnostic accuracy of CFVR by TTDE for detecting significant LAD stenosis remains high in a more clinically relevant population with multiple cardiovascular co-morbidities. Only the presence of LVH adversely affected diagnostic accuracy.

Direct demonstration by transthoracic Doppler echocardiography of adenosine-induced coronary steal in the collateral-dependent vessel

Coronary flow velocity reserve was measured to assess the frequency of coronary steal in the collateral-dependent coronary arteries using transthoracic Doppler echocardiography. Coronary steal occurred in half the vessels studied. There was no significant difference between coronary flow velocity reserve in poorly and well-developed collaterals.

Quantitative Assessment of Regional Myocardial Flow Reserve Using Tc-99m-Sestamibi Imaging-Comparison With Results of O-15 Water PET-

BACKGROUND

The aims of this study were to develop a method for quantitative estimation of the myocardial blood flow index (MBFI) and myocardial flow reserve (MFR) of the whole left ventricle using (99m)technetium (Tc-99m)-sestamibi imaging.

METHODS AND RESULTS

Twenty-two patients with suspected coronary artery disease and 7 controls underwent both Tc-99m-sestamibi imaging and O-15 water positron emission tomography (PET). The global MBFI was calculated on the basis of the microsphere model from the ratio of the myocardial count to the area under the time - activity curve on the aortic arch. The regional MBFI was calculated from the relative distributions of Tc-99m-sestamibi uptake values. The regional MBFI and MFR (Tc-MFR) obtained using single-photon emission computed tomography were compared with the myocardial blood flow (MBF) and MFR (PET-MFR) obtained using PET as the gold standard. Regional MBFI significantly correlated with the MBF obtained using PET. Regional Tc-MFR also correlated with the regional PET-MFR, with some underestimation.

CONCLUSION

These results indicate that regional MBF and MFR may be estimated by dynamic Tc-99m-sestamibi imaging and can be used for the early detection and estimation of the functional severity of coronary lesions without the need for a PET camera.

[Measurement of coronary flow and flow reserve with transthoracic echocardiography: an old concept, a new tool, a lot of applications]

Non invasive evaluation of coronary flow and flow reserve by using transthoracic echocardiography is a promising method for evaluating coronary disease. Left anterior descending and right posterior descending coronary flow are accessible in the majority of patients. This technique is useful in various settings: detection of coronary artery stenosis, coronary occlusion, follow up after percutaneous coronary intervention, evaluation of the significance of coronary stenosis of intermediate severity, evaluation of the microcirculation, study of reperfusion and no reflow in the acute phase of myocardial infarction, evaluation of bypass grafts, improvement of the diagnostic accuracy during stress echocardiography. After a period of training, it's possible to change an old concept, formerly not easily accessible in clinical practice, into a useful and modern tool for evaluating coronary artery disease.

Oolong tea increases plasma adiponectin levels and low-density lipoprotein particle size in patients with coronary artery disease

BACKGROUND

Oolong tea has been studied for its effect on cardiovascular disease and obesity. Plasma adiponectin levels are reduced in obesity, in patients with type 2 diabetes mellitus and in coronary artery disease (CAD).

OBJECTIVE

To investigate prospectively, whether intake of Oolong tea influences plasma adiponectin levels, low-density lipoprotein (LDL) particle size, total cholesterol, high-density lipoprotein (HDL) cholesterol, LDL cholesterol, serum triglyceride and plasma glucose levels in patients with CAD.

METHODS

Twenty two patients in our study consumed Oolong tea (1000 ml) or water for 1 month in our randomized cross-over study design.

RESULTS

There was a significant difference in plasma adiponectin levels before and after 1 month intake of Oolong tea (6.26 +/- 3.26 microg/ml versus 6.88 +/- 3.28 microg/ml, P < 0.05), and in plasma level LDL particle size (25.02+/-0.67 nm versus 25.31+/-0.60 nm, P < 0.01). The water-consuming control group showed no changes (6.28+/-3.28 microg/ml versus 6.23+/-3.21 microg/ml) in adiponectin levels or LDL particle sizes (25.03+/-0.70 nm versus 25.02+/-0.72 nm). We also observed a significant difference in hemoglobin A1c levels (7.23 +/- 4.45% versus 6.99 +/- 4.30%, P < 0.05) before and after intake of Oolong tea.

CONCLUSION

Oolong tea may have beneficial effects on the progression of atherosclerosis in patients with CAD.

Usefulness of High-Frequency Transthoracic Doppler Echocardiography in Noninvasive Diagnosis of the Left Internal Thoracic Artery Graft Stenosis at the Anastomosis

BACKGROUND

Stenosis of the left internal thoracic artery (LITA) graft, which usually occurs at the site of the anastomosis, can be noninvasively evaluated by the flow pattern in the proximal graft, but the flow pattern is influenced by several other factors.

METHODS AND RESULTS

In the present study, LITA graft flow was investigated by high-frequency transthoracic Doppler echocardiography in 75 consecutive patients who underwent postoperative angiography of the LITA graft. The flow velocity was measured at both the anastomosis and proximal to it, and compared with the quantitative angiographic results. Flow at both sites was detected in 61 (81%) of the 75 patients. The diastolic velocity ratio of the anastomosis to the proximal site correlated with the percent diameter stenosis at the anastomosis. A diastolic velocity ratio >2.0 had a high sensitivity, specificity, positive predictive value and negative predictive value for the presence of significant stenosis at the anastomosis of a LITA graft.

CONCLUSIONS

High-frequency transthoracic Doppler echocardiography can be used for the noninvasive diagnosis of LITA graft stenosis.