Inverse correlation between coronary and retinal blood flows in patients with normal coronary arteries and slow coronary blood flow

Predictive Value of Ocular Fundus Hemorrhage for Severe Coronary Artery Disease Assessed via SYNTAX Score

Aims/Background The relationship between retinal fundus hemorrhage and the severity of coronary artery lesions remains unclear. This study aimed to explore the incidence of fundus hemorrhage in patients at high risk of coronary heart disease (CHD) and to examine its correlation with the SYNTAX score, a tool used to assess the complexity of coronary artery disease. Methods This retrospective study consecutively enrolled patients undergoing coronary angiography (CAG) at Beijing Anzhen Hospital Hospital from June 2019 to January 2020. Bilateral non-mydriatic fundus photography was performed to detect fundus hemorrhages. The SYNTAX score was calculated to quantify the severity of coronary artery lesions, and patients were divided into two groups: a high SYNTAX score (hSS) group (≥23 points) and a low SYNTAX score (lSS) group (≤22 points). Baseline demographic and clinical data were collected, along with relevant laboratory tests. Results A total of 878 patients were included in the study, with 177 in the hSS group and 701 in the lSS group. Fundus hemorrhage was observed in 91 patients (incidence: 10.36%, 95% confidence interval (CI): 8.35%-12.38%). The incidence of fundus hemorrhage was significantly higher in the hSS group compared to the lSS group (21.47% [38/177] vs. 7.56% [53/701], p < 0.001). Multivariate logistic regression analysis identified fundus hemorrhage, body mass index (BMI), and low-density lipoprotein cholesterol (LDL-C) as independent predictors of high SYNTAX scores. Conclusion Fundus hemorrhage is significantly associated with a higher SYNTAX score and may serve as a potential predictor of severe coronary artery lesions in clinical practice.

Major Adverse Cardiovascular Events and Prognosis in Patients With Coronary Slow Flow

This study aimed to investigate its clinical implications, risk factors, prognosis, and overall long-term outcomes. Demographic profiles, various clinical characteristics, and clinical outcomes were compared between 614 patients with coronary slow flow (CSF) and 428 patients with normal coronary artery. The incidence of CSF was found to be 2.65%. Significant differences were observed between patients with CSF and control subjects in terms of sex, chest tightness, hyperlipidemia, smoking history, alcohol consumption, age, height, weight, body mass index, diastolic blood pressure, heart rate, and body surface area (P < 0.05). CSF (hazard ratio: 1.531; 95% confidence interval: 1.064-2.202; p = 0.022) proved to be independent prognostic predictors of major adverse cardiovascular events (MACEs). Kaplan-Meier survival evaluations for MACEs presented a worser outcome for patients with CSF. Patients with CSF are at high risk for cardiovascular events and experience generally poor clinical outcomes.

Association of retinal microvascular density and complexity with incident coronary heart disease

BACKGROUND AND AIMS

The high mortality rate and huge disease burden of coronary heart disease (CHD) highlight the importance of its early detection and timely intervention. Given the non-invasive nature of fundus photography and recent development in the quantification of retinal microvascular parameters with deep learning techniques, our study aims to investigate the association between incident CHD and retinal microvascular parameters.

METHODS

UK Biobanks participants with gradable fundus images and without a history of diagnosed CHD at recruitment were included for analysis. A fully automated artificial intelligence system was used to extract quantitative measurements that represent the density and complexity of the retinal microvasculature, including fractal dimension (Df), number of vascular segments (NS), vascular skeleton density (VSD) and vascular area density (VAD).

RESULTS

A total of 57,947 participants (mean age 55.6 ± 8.1 years; 56% female) without a history of diagnosed CHD were included. During a median follow-up of 11.0 (interquartile range, 10.88 to 11.19) years, 3211 incident CHD events occurred. In multivariable Cox proportional hazards models, we found decreasing Df (adjusted HR = 0.80, 95% CI, 0.65-0.98, p = 0.033), lower NS of arteries (adjusted HR = 0.69, 95% CI, 0.54-0.88, p = 0.002) and venules (adjusted HR = 0.77, 95% CI, 0.61-0.97, p = 0.024), and reduced arterial VSD (adjusted HR = 0.72, 95% CI, 0.57-0.91, p = 0.007) and venous VSD (adjusted HR = 0.78, 95% CI, 0.62-0.98, p = 0.034) were related to an increased risk of incident CHD.

CONCLUSIONS

Our study revealed a significant association between retinal microvascular parameters and incident CHD. As the lower complexity and density of the retinal vascular network may indicate an increased risk of incident CHD, this may empower its prediction with the quantitative measurements of retinal structure.

Coronary microvascular dysfunction is associated with impaired cognitive function: the Cerebral-Coronary Connection study (C3 study)

BACKGROUND

It remains unknown whether the presence of coronary microcirculatory dysfunction (CMD) correlates with its equivalent condition in the brain, cerebral small vessel disease (CSVD). The cerebral-coronary connection (C3), a prospective blinded study, investigated the prevalence of CMD in patients with coronary artery disease (CAD) and its association with CSVD and cognitive function.

METHODS AND RESULTS

Patients with documented CAD fulfilling inclusion criteria underwent physiological assessment of epicardial vessels and the microcirculation using intracoronary pressure and Doppler. Coronary microcirculation-related indices included coronary flow reserve (CFR) and hyperaemic microvascular resistance. Brain magnetic resonance imaging, transcranial Doppler (TCD), and neurocognitive examination were performed. Overall, 67 patients were included in the study (mean age 66 years, 73% female). Patients with abnormal CFR (<2.0) (55.2%) showed higher burden of white-matter hyperintensities: 43.2 vs. 20.0% (P = 0.044). After statistical adjustment, low CFR was associated with lower grey matter volume (P = 0.024) and with parameters of white-matter microstructural damage in diffusion-tensor imaging (lower fractional anisotropy and higher mean diffusivity, P = 0.029 and P = 0.032, respectively). Low CFR was associated with higher resistive (P = 0.027) and pulsatility (P = 0.043) values on TCD, and worse neurocognitive test scores (lower mini mental state examination, P = 0.025, and slower Trail Making Test A, P = 0.034).

CONCLUSIONS

Coronary microcirculatory dysfunction is frequent in patients with CAD and correlates with CSVD, abnormal cerebral flow haemodynamics, and significant cognitive impairment. These findings support the hypothesis that microvascular dysfunction in the heart and the brain are part of a single pathological process affecting microcirculation in patients with CAD.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT04131075.

Alprostadil vs. isosorbide dinitrate in ameliorating angina episodes in patients with coronary slow flow phenomenon: A randomized controlled trial

Background

The optimum therapy for coronary slow flow phenomenon (CSFP) stays debatable. This study compared the effectiveness of alprostadil with isosorbide dinitrate in alleviating angina episodes in CSFP patients.

Methods

In this prospective, randomized controlled study, 102 patients with CSFP without severe coronary artery stenosis that exhibited stable angina were allocated randomly in a ratio of 1:1 to either the alprostadil group (40 μg, three times per day, n = 51) or the isosorbide dinitrate group (5 mg, three times per day, n = 51). Frequency of angina events, intensity of suffering, and the Canadian Cardiovascular Society (CCS) grading of angina pectoris were evaluated at baseline and one month after. Additionally, the Seattle Angina Questionnaire (SAQ) was assessed.

Results

Baseline characteristics were comparable between the two groups. At 1-month follow-up, patients administered with alprostadil experienced fewer angina episodes [episodes per week, 1 (2) vs. 2 (2), P < 0.001] and less pain intensity [self-evaluated pain score, 2 (3) vs. 3 (4), P < 0.001] than those with isosorbide dinitrate. In the alprostadil group, 78.4% of patients were classified as CCS class I, significantly higher than the 47.1% seen in the isosorbide dinitrate group (P = 0.001). Furthermore, treatment of alprostadil led to a significant improvement in the SAQ score (7.09 U, 95% CI: 4.22–9.96, P < 0.001) compared to isosorbide dinitrate. Additionally, fewer patients suffered headaches when receiving alprostadil (7.8% vs. 19.6%, P = 0.084).

Conclusion

Alprostadil was more effective in ameliorating angina symptoms in CSFP patients than isosorbide dinitrate.

Clinical trial registration

[www.chictr.org.cn], identifier [ChiCTR2000033233].

Microvascular Dysfunction as a Systemic Disease: A Review of the Evidence

Microvascular dysfunction describes a varied set of conditions that includes vessel destruction, abnormal vasoreactivity, in situ thrombosis, and fibrosis, which ultimately results in tissue damage and progressive organ failure. Microvascular dysfunction has a wide array of clinical presentations, ranging from ischemic heart disease to renal failure, stroke, blindness, pulmonary arterial hypertension, and dementia. An intriguing unifying hypothesis suggests that microvascular dysfunction of specific organs is an expression of a systemic illness that worsens with age and is accelerated by vascular risk factors. Studying relationships across a spectrum of microvascular diseases affecting the brain, retina, kidney, lung, and heart may uncover shared pathologic mechanisms that could inform novel treatment strategies. We review the evidence that supports the notion that microvascular dysfunction represents a global pathologic process. Our focus is on studies reporting concomitant microvascular dysfunction of the heart with that of the brain, kidney, retina, and lung.

Functional slit lamp biomicroscopy metrics correlate with cardiovascular risk

PURPOSE

Our aim was to correlate cardiovascular risk factor estimation with bulbar conjunctival blood flow metrics as measured through Functional Slit Lamp Biomicroscopy (FSLB).

METHODS

Cross-sectional study of individuals with otherwise healthy eyelid and corneal anatomy recruited from the Miami Veterans Affairs (VA) Healthcare System eye clinic. We measured conjunctival microvascular hemodynamics by mounting a camera on a slit lamp and cardiovascular risk using the Framingham risk score. Our main outcome measures were correlations between conjunctival vessel parameters (axial and cross-sectional blood flow velocity, blood flow rate) and Framingham score.

RESULTS

We included 84 patients who underwent FSLB. The mean age was 60 years, the majority were male (88%) and approximately half the patients were black (54%). Mean vessel diameter was similar between all Framingham score categories. Axial and cross-sectional blood flow velocities and blood flow rate were lower in individuals with higher Framingham risk score. Specifically, mean cross-sectional blood flow velocity in individuals with a low Framingham risk score was 0.37 ± 0.0.9 mm/s, with an intermediate score was 0.30 ± 0.09 mm/s, and with a high score was 0.29 ± 0.10 mm/s, p = 0.04. Mean blood flow rate in individuals with a low Framingham risk score was 133.4 ± 59.6 pl/s, with an intermediate score was 123.6 ± 39.3 pl/s, and with a high score was 121.9 ± 52.6 pl/s, p = 0.04. The beta coefficient of the blood flow rate for change in Framingham score was -0.73; 95% CI-1.34-0.13, p = 0.02, adjusted for race.

CONCLUSION

FSLB correlates with cardiovascular risk estimation. Future studies should evaluate if FSLB can predict cardiovascular outcomes.

The retinal function imager and clinical applications

Background

The Retinal Function Imager (RFI) provides in vivo and noninvasive imaging of both the retinal structure and function.

Review

The RFI can create capillary perfusion maps, measure blood flow velocity, and determine metabolic function including blood oximetry. It can aid clinical diagnosis as well as assess treatment response in several retinal vascular diseases including diabetic retinopathy. Blood flow velocity abnormalities have also been implicated in disease such as age-related macular degeneration and require further investigation. Compared with optical coherence tomography angiography, the RFI produces capillary maps of comparable image quality and wider field of view but it is unable to provide depth-resolved information and has longer image acquisition time. Currently, functional imaging using blood oximetry has limited applications and additional research is required.

Conclusion

The RFI offers noninvasive, high-resolution imaging of retinal microvasculature by creating capillary perfusion maps. In addition, it is capable of measuring retinal blood velocity directly and performs functional imaging with retinal blood oximetry. Its clinical applications are broad and additional research with functional imaging may potentially lead to diagnosis of diseases and their progression before anatomic abnormalities become evident, but longer image acquisition times may limit its clinical adoption.

Circulating miRNA-155 as a Potential Biomarker for Coronary Slow Flow

Objective

Recent studies have demonstrated that miRNA-155 is involved in the occurrence and development of atherosclerosis. Furthermore, miRNA-155 has emerged as a new indirect marker for inflammation associated with adverse outcomes in oncology and cardiovascular diseases. This study investigated the correlation between the levels of miRNA-155 and coronary slow flow (CSF).

Methods

A total of 66 patients with CSF and 66 patients with normal coronary flow were enrolled in this study. Coronary flow velocity was determined using the thrombolysis in myocardial infarction frame count (TFC) method. The plasma levels of miRNA-155 were quantified using real-time quantitative polymerase chain reaction.

Results

The plasma levels of miRNA-155 were significantly higher in the CSF group compared to the control group (P < 0.05). In addition, miRNA-155 levels were positively correlated with TFC and high-sensitivity C-reactive protein (hs-CRP) levels (P < 0.05 for both parameters). Multivariate linear regression analysis demonstrated that plasma miRNA-155 (OR = 2.384, 95% confidence interval 1.847–3.273, P = 0.032) and hs-CRP (OR = 1.273, 95% confidence interval 1.036–2.253, P = 0.013) were independent predictors for CSF. Using plasma miRNA-155 levels as the test variable, ROC curve analysis indicated that the area under the curve was 0.782 (P < 0.05).

Conclusion

Patients with CSF have higher plasma levels of miRNA-155, and this may play an important role in the pathogenesis of CSF, and an elevated plasma miRNA-155 level may be a predictor for CSF. A large-scale and multicenter study is required to elucidate the role of miRNA-155 as a potential biomarker for patients with CSF.

A Mini Review of Clinical and Research Applications of the Retinal Function Imager

PURPOSE

To review the clinical applications and diagnostic value of the retinal function imager (RFI), briefly compare RFI to other optical imaging devices, and to describe recent developments.

METHODS

The search words "Retinal Functional Imager," "optical imaging," "retina angiography," "avascular zone," "foveal avascular zone," and other closely related terms were used in PubMed to review current literature involving the RFI.

RESULTS

The functions of the RFI were utilized in over 44 microvascular studies, which reported that the microvasculature may alter in velocity, morphology, and oximetry when affected by a number of ocular, neurological, or systemic diseases. Recently developed automatic algorithms for noninvasive angiography of large retinal regions, segmenting vessels, measuring blood flow, blood velocity, vessel diameter, and oximetry may enhance the clinical applications of the RFI.

CONCLUSION

The RFI has been used to characterize the retinal microvasculature under various conditions of all prevalent retinal diseases in addition to some central nerve system (CNS) and systemic diseases. Applying the RFI in research and clinical settings should help earlier diagnosis, support disease prevention, and improve treatment management.

Noninvasive, High-Resolution Functional Macular Imaging in Subjects With Retinal Vein Occlusion

BACKGROUND AND OBJECTIVES

Several imaging modalities have been developed to characterize ischemia inherent in retinal vascular diseases. This study aims to predict the impact and to better establish the mechanisms of visual deterioration. A high-resolution functional imaging device is used, yielding quantitative data for macular blood flow and capillary network features in healthy eyes and in eyes with central retinal vein occlusion (CRVO) or branch retinal vein occlusion (BRVO).

PATIENTS AND METHODS

This prospective, cross-sectional, comparative case series measured blood flow velocities (BFVs) and noninvasive capillary perfusion maps (nCPMs) in macular vessels in patients with BRVO/CRVO and in healthy controls using the Retinal Function Imager (RFI; Optical Imaging, Rehovot, Israel).

RESULTS

Twenty-two eyes of 21 subjects were studied (eight with CRVO, five with BRVO, and nine controls). A significant decrease was observed in the BFVs of both arterioles and venules in the affected macular region of patients with CRVO and BRVO (2.84 ± 1.21 mm/s and 2.67 ± 1.43 mm/s in CRVO/BRVO arterioles, respectively, vs. 4.23 ± 1.04 mm/s in healthy controls, P < .001; and 1.64 ± 0.51 mm/s and 1.60 ± 0.41 mm/s in CRVO/BRVO venules, respectively, vs. 2.88 ± 0.93 mm/s in healthy controls, P < .001). BFVs in non-affected macular regions of patients with BRVO were not statistically different from BFVs in healthy eyes (3.84 ± 1.04 mm/s and 3.17 ± 1.39 mm/s in BRVO patients vs. 4.23 ± 1.04 mm/s and 2.88 ± 0.93 mm/s in healthy controls' arterioles and venules, respectively; P ≥ .1). nCPMs allowed high-resolution imaging of the macular vasculature and successfully demonstrated ischemic areas in the RVO groups.

CONCLUSIONS

The RFI provided high-resolution functional imaging of the retinal microvasculature and enabled quantitative measurement of BFVs in patients with RVO. Diminished flow velocity in arterioles and venules raises the possibility that RVO represents a panvascular compromise not confined to just venous stasis or its secondary arteriolar effects. The RFI offers potential to help with diagnosis and management of RVO cases. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:799-809.].

High red blood cell distribution width is associated with the metabolic syndrome

OBJECTIVES

High values of Red Blood Cell Distribution Width (RDW) have been associated with adverse outcome in various clinical settings. The mechanism behind this association is not clear. The Metabolic Syndrome (MetS) is a chronic inflammatory disorder that increases the risk for cardiovascular disease and death. The aim of our study was to evaluate the association between high RDW and the MetS in a relatively large cohort of patients.

METHODS

A cohort of 3,529 consecutive patients undergoing coronary angiography was used to evaluate the association between RDW and the MetS. The association was assessed by using a logistic regression. Cox's regression analysis was used to evaluate the impact of RDW on long term mortality.

RESULTS

The mean age was 65 years (range 24-97), with 27% women. Overall, 30% were diagnosed with metabolic syndrome. The prevalence of MetS was 29% in patients with RDW <14% and 34% in patients with RDW ≥14% (P = 0.003).Using multivariate analysis, RDW values above 14% were independently associated with MetS (odds ratio 1.2 [95% CI 1.0-1.4], P = 0.043). Among all the criteria of the metabolic syndrome, hypertension, elevated glucose levels and abdominal obesity were associated with high RDW, with hypertension being the strongest criteria, with an increased risk of 1.8 fold ([95% CI 1.5-2.1]; P = 0.001). During follow up (1614 ± 709 days, 2-2763 days), long term mortality was 8% in the low RDW group and 28% in the high RDW group (p < 0.001).

CONCLUSION

RDW ≥14% is independently associated with higher rates of metabolic syndrome and long-term all-cause mortality.

HbA1c Levels and Long-Term Mortality in Patients Undergoing Coronary Angiography

OBJECTIVES

Previous studies investigating the prognostic value of HbA1c in patients undergoing coronary angiography reported a mixed pattern of results. Therefore, we aimed to better define the prognostic power of HbA1c among coronary catheterized patients.

METHODS

Patients undergoing coronary angiography (n = 3,749) were divided into four groups according to HbA1c levels (<5, 5-6, 6-7 and >7%). Cox regression models assessed long-term mortality after adjusting for multiple covariates.

RESULTS

Baseline clinical profiles differed in HbA1c groups, with a higher prevalence of comorbidities in the groups with higher HbA1c levels. Median follow-up was 1,745 days (interquartile range 1,007-2,171). A J-shaped association curve was observed between HbA1c levels and all-cause mortality rates, with patients in the lowest and highest HbA1c groups suffering from significantly higher mortality rates compared to in-between groups (hazard ratio 1.9, 95% CI 1.32-2.74, p = 0.001, and hazard ratio 1.58, 95% CI 1.29-1.95, p < 0.001, for the lowest and highest HbA1c groups, respectively). This association persisted after adjustment for anemia, nutritional status, renal function, cardiovascular risk factors and inflammatory biomarkers.

CONCLUSIONS

HbA1c levels <5 or >7% are predictors of all-cause mortality in patients undergoing coronary angiography.

Impaired retinal microcirculation in multiple sclerosis

BACKGROUND

The transparent ocular structure enables quantitative analysis of microvasculature of retina, a neuronal tissue affected by multiple sclerosis (MS).

OBJECTIVE

The aim of this study was to determine whether the retinal blood flow velocity and flow volume at the macula are impaired in patients with relapsing remitting multiple sclerosis (RRMS).

METHODS

A total of 17 RRMS patients and 17 age- and gender-matched healthy subjects were assessed. A retinal function imager was used to measure the blood flow velocity of retinal arterioles and venules and to calculate the total perifoveal blood flow volume.

RESULTS

The blood flow velocities of the retinal arterioles (3.34 ± 0.89 mm/s) and venules (2.61 ± 0.6 mm/s) were significantly lower in MS patients than normal subjects (arteriole: 4.10 ± 0.87 mm/s; venule: 3.22 ± 0.65 mm/s, both p = 0.01). In addition, the total perifoveal blood flow volume in arterioles (3.74 ± 1.64 nL/s) and venules (3.81 ± 1.60 nL/s) were significantly lower in MS patients than in normal subjects (arteriole: 4.87 ± 1.41 nL/s, p = 0.02; venule: 4.71 ± 1.64 nL/s, p = 0.04).

CONCLUSION

The impaired retinal microcirculation in RRMS patients indicates microvascular dysfunction in MS.

Assessment of potential vessel segmentation pitfalls in the analysis of blood flow velocity using the Retinal Function Imager

PURPOSE

The purpose of our study was to investigate the potential pitfalls associated with different vessel segmentation methods using the built-in software of the Retinal Function Imager (RFI) for the analysis of retinal blood flow velocity (BFV).

METHODS

Ten eyes of nine healthy subjects were enrolled in the study. Retinal blood flow measurements were obtained with the RFI device with a 20° field of view imaging. The same grader segmented the retinal vasculature using the RFI software in both sessions, with segments ranging in length from 50 to 100 pixels ("short segments") and 100-200 pixels ("long segments"). The blood flow velocities for the arteriolar and venular system were calculated, and the percentage of excluded vessel segments with high coefficients of variation (>45 %) was recorded and compared by paired t test. Spearman's correlation was used to analyze the relationship between measurements by the two vessel segmentation methods.

RESULTS

The number of analyzed vessel segments did not differ significantly between the two groups (28.6 ± 2.6 short and 26.7 ± 4.6 long segments), while the percentage of acceptable segments was significantly higher in the long segment group (65.2 ± 11.4 % vs 85.2 ± 5.87 %, p = 0.001). In the short segment group, more than 15 % of vessel segments were rejected in all subjects, while in the long segment group only three subjects had a rejection rate of greater than 15 % (16.7 %, 18.7 % and 28 %). Both arteriolar and venular velocities were lower in the short segment group, although it reached significance only for arteriolar velocities (3.93 ± 0.55 vs. 4.45 ± 0.76 mm/s, p = 0.036 and 2.95 ± 0.56 vs. 3.17 ± 0.84 mm/s, p = 0.201 for arterioles and venules, respectively). Only venular velocities showed significant correlation (p = 0.003, R (2) = 0.67) between the two groups.

CONCLUSIONS

Our results suggest that BFV measurements by the RFI may be affected by segment length, and care should therefore be taken in choosing vessel segment lengths used during the analysis of RFI data. Long segments of 100-200 pixels (400-800 μm) seem to provide more robust measurements, which can be explained by the analysis methodology of the RFI device.

Relation of metabolic syndrome with long-term mortality in acute and stable coronary disease

Past studies examining the effects of the metabolic syndrome (MS) on prognosis in postangiography patients were limited in size or were controversial in results. The aim of the study was to examine the association of the MS and the risk for long-term mortality in a large cohort of patients undergoing coronary angiography for various clinical indications. Medical history, physical examination, and laboratory values were used to diagnose patients with the MS. Cox regression models were used to analyze the effect of MS on long-term all-cause mortality. We prospectively recruited 3,525 consecutive patients with a mean age of 66 ± 22 years (range 24 to 97) and 72% men. Thirty percent of the cohort had MS. Patients with MS were more likely to have advanced coronary artery disease and acute coronary syndrome (p <0.001). Patients with MS had more abnormalities in their metabolic and inflammatory biomarkers regardless of their clinical presentation. A total of 495 deaths occurred during a mean follow-up period of 1,614 ± 709 days (median 1,780, interquartile range 1,030 to 2,178). MS was associated with an increased risk of death in the general cohort (hazard ratio [HR] 1.27, 95% confidence interval [CI] 1.01 to 1.56, p = 0.02). MS had a significant effect on mortality in stable patients (HR 1.55, 95% CI 1.1 to 2.18, p = 0.01), whereas it did not have a significant effect on mortality in patients with acute coronary syndrome (HR 1.11, 95% CI 0.86 to 1.44, p = 0.42). In conclusion, MS is associated with increased mortality in postangiography patients. Its adverse outcome is mainly seen in patients with stable angina.

Hyperglycemia in patients referred for cardiac catheterization is associated with preexisting diabetes rather than a stress-related phenomenon: a prospective cross-sectional study

BACKGROUND

An increased serum glucose level in patients with acute coronary syndrome (ACS) is associated with adverse clinical outcome. This hyperglycemia has been attributed, at least in part, to acute stress reaction. Our objective was to determine whether hyperglycemia is a stress-related phenomenon or whether it represents a more sustained and possibly significant background dysglycemia.

HYPOTHESIS

Hyperglycemia in patients undergoing coronary angiography is related to background dysglycemia.

METHODS

Blood samples were obtained at the time of cardiac catheterization. Patients with hemoglobin A1c >6.5% were excluded to avoid patients with chronic glucose levels above 135 mg/dL. A logistic regression model was created to assess the influence of different variables on hyperglycemia (glucose levels above 140 mg/dL). We also evaluated the effect of glucose levels above 140 mg/dL on major adverse cardiovascular events (MACEs) up to 36 months.

RESULTS

There were 2554 consecutive patients prospectively recruited. Serum glucose levels above 140 mg/dL was a strong predictor of MACE (hazard ratio: 2.2, 95% confidence interval [CI]: 1.3-3.6, P = 0.002). Both diabetes mellitus and ACS were associated with hyperglycemia (glucose levels above 140 mg/dL). Nevertheless, the incidence of hyperglycemia was doubled in diabetic patients (odds ratio [OR]: 9.4, 95% CI: 3.9-22.4, P < 0.001) compared with patients with ACS (OR: 4.6, 95% CI: 2.3-9.0, P < 0.001). Combining both conditions was associated with a high likelihood of elevated glucose levels (OR: 15.5, 95% CI: 7.4-32.9, P < 0.001).

CONCLUSIONS

Hyperglycemia in patients undergoing cardiac catheterization is a strong predictor of adverse outcome. It is mainly related to background dysglycemia and to a lesser extent to the acute stress accompanying ACS.