Optical coherence tomography derived differences of plaque characteristics in coronary culprit lesions between type 2 diabetic patients with and without acute coronary syndrome.

OBJECTIVE: To compare optical coherence tomography (OCT)-derived plaque characteristics of coronary target lesions between diabetic patients with acute coronary syndrome (ACS) versus stable angina pectoris (SAP). BACKGROUND: In vivo assessment of plaque composition of coronary culprit lesions in a cardiovascular high-risk population with diabetes mellitus is incompletely elucidated. METHODS: 102 diabetic patients with coronary de novo lesions were enrolled and categorized into an ACS-group (40 patients) and a SAP-group (62 patients) according to their clinical presentation. Assessment of clinical data, angiographic, and OCT imaging including the analysis of plaque composition and lipid content of the target lesions were performed prior to percutaneous coronary intervention and compared between the two groups. RESULTS: Plaque characteristics of patients in the ACS-group compared with the SAP-group showed a higher incidence of lipid-rich plaque [33 (82.5%) vs. 25 (40.3%)], thin-capped fibroatheroma [29 (72.5%) vs. 10 (16.1%)], macrophage infiltration [32 (80.0%) vs. 21 (33.9%)], thrombus [23 (57.5%) vs. 2 (3.2%)], and plaque rupture [27 (67.5%) vs. 2 (3.2%)] (all P < 0.001). Moreover, there was a wider lipid arc (174.5 ± 33.8° vs. 122.9 ± 43.9°), a longer lipid plaque length (6.52 ± 2.04 mm vs. 3.73 ± 2.16 mm), a greater lipid volume index (1117.2 ± 349.9 vs. 504.8 ± 379.3), and a smaller minimal fibrous cap thickness (51.52 ± 9.14 µm vs. 80.33 ± 26.71 µm) within lipid-rich lesions of ACS patients (all P < 0.001). CONCLUSION: Diabetic patients with ACS exhibit more vulnerable plaque features in coronary culprit lesions compared with diabetic patients with SAP. This may provide rationale for a specific therapeutic strategy either by pharmacological plaque stabilization or coronary intervention in any lesion with vulnerable plaque morphology in patients with diabetes.

Plaque vulnerability of coronary artery lesions is related to left ventricular dilatation as determined by optical coherence tomography and cardiac magnetic resonance imaging in patients with type 2 diabetes.

BACKGROUND: Patients with type 2 diabetes are at increased risk for both, left ventricular (LV)-dilatation and myocardial infarction (MI) following the rupture of a vulnerable plaque. This study investigated the to date incompletely understood relationship between plaque vulnerability and LV-dilatation using optical coherence tomography (OCT) and cardiac magnetic resonance imaging (CMR) in patients with type 2 diabetes and stable coronary artery disease. METHODS: CMR was performed in 58 patients with type 2 diabetes, in which 81 coronary lesions were investigated using OCT. RESULTS: A decreased minimal fibrous cap thickness (FCT) of coronary lesions was associated with an increase of several CMR-derived parameters including LV-end diastolic volume (LVEDV, r = 0.521, p < 0.001), LV-end diastolic diameter (r = 0.502, p < 0.001) and LV-end systolic volume (r = 0.467, p = 0.001). Similar results were obtained for mean FCT. CONCLUSION: These data suggest that vulnerability of coronary lesions is associated with LV-dilatation in high risk patients with type 2 diabetes. CMR may be a useful adjunct to the risk-stratification in this population. Future studies are warranted to investigate potential mechanisms linking plaque vulnerability and LV-dilatation.

High cardiovascular risk of patients with type 2 diabetes is only partially attributed to angiographic burden of atherosclerosis.

BACKGROUND: Patients with type 2 diabetes (T2DM) are at high risk for cardiovascular events and present more severe coronary artery disease (CAD). The Gensini and COURAGE scores are established angiographic instruments to assess CAD severity, which may also predict future cardiovascular risk. However, it is unclear if these scores are able to depict the increased risk of patients with T2DM and stable CAD (T2DM-SAP). METHODS: We performed quantitative coronary angiography and assessed the Gensini and COURAGE scores in 124 patients with T2DM-SAP. Angiographic data were compared to patients with stable angina without T2DM (Non-DM-SAP, n = 74), and to patients with acute coronary syndrome and T2DM (T2DM-ACS, n = 53). RESULTS: T2DM-SAP patients had similar Gensini and COURAGE-scores compared to Non-DM-SAP-patients (Gensini: 14.44 ± 27.34 vs 11.49 ± 26.99, p = 0.465; COURAGE: 3.48 ± 4.49 vs 3.60 ± 4.72, p = 0.854). In contrast, T2DM-SAP patients had significantly lower Gensini (14.44 ± 27.34 vs 30.94 ± 48.74, p = 0.003) and lower COURAGE (3.48 ± 4.49 vs 5.30 ± 4.63, p = 0.016) scores compared to T2DM-ACS-patients. CONCLUSION: Both the Gensini and the COURAGE score fail to predict the high cardiovascular risk of patients with T2DM-SAP. Therefore, these scores should be used with caution in the assessment of future risk of patients with T2DM. However, among T2DM-ACS patients, both scores are increased, reflecting the high cardiovascular risk in this patient population.

Correlation between optical coherence tomography-derived intraluminal parameters and fractional flow reserve measurements in intermediate grade coronary lesions: a comparison between diabetic and non-diabetic patients.

BACKGROUND: Fractional flow reserve (FFR) measurements accurately assess functional relevance in intermediate grade coronary lesions. A significant relationship between hemodynamic stenosis severity and optical coherence tomography (OCT)-derived intraluminal dimensions has recently been demonstrated. However, morphologic thresholds to identify significant stenoses are variable and exploration of this correlation in patients with diabetes mellitus (DM) remains currently incomplete. This study aimed at comparing the diagnostic value of intraluminal parameters as determined by OCT to predict FFR ≤0.8 in lesions of patients with versus without DM. METHODS: In 100 patients (DM = 56, non-DM = 44) with 142 coronary de novo lesions (DM = 80, non-DM = 62) of intermediate grade as determined by quantitative coronary angiography, we performed OCT and FFR. Stenoses were defined functionally relevant if FFR was ≤0.8. RESULTS: FFR measurements in the overall study cohort, the DM and the non-DM group correlated significantly with minimal lumen area (MLA) [overall: r (2) = 0.339, DM: r (2) = 0.341, non-DM: r (2) = 0.355 (all p < 0.001)], percent area stenosis [overall: r (2) = 0.352, DM: r (2) = 0.376, non-DM: r (2) = 0.351 (all p < 0.001)] and minimal lumen diameter [overall: r (2) = 0.333, DM: r (2) = 0.277, non-DM: r (2) = 0.417 (all p < 0.001)] without differing statistically between diabetic and non-diabetic patients (p = ns). Receiver operating characteristic analysis demonstrated that among OCT-derived parameters, MLA predicted FFR ≤0.8 with the best diagnostic efficiency and with similar cut-off values for all patients [area under the curve (AUC) = 0.836, 95% confidence interval (CI) = 0.772-0.901, cut-off value = 1.64 mm(2)] as well as for diabetic (AUC = 0.840, 95% CI = 0.754-0.927, cut-off value = 1.59 mm(2)) and non-diabetic subjects (AUC = 0.833, 95% CI = 0.734-0.932, cut-off value = 1.64 mm(2)). CONCLUSION: In both, diabetic and non-diabetic patients, FFR and OCT-derived intraluminal measurements are significantly correlated and OCT predicts hemodynamically relevant coronary stenosis with moderate diagnostic efficiency.

Correlation between OCT-derived intrastent dimensions and fractional flow reserve measurements after coronary stent implantation and impact on clinical outcome.

BACKGROUND: Insufficient stent expansion, vessel wall injury, and tissue prolapse, all frequently unrecognized by coronary angiography, are predictors of future major adverse cardiac event (MACE) after percutaneous coronary intervention (PCI). Optical coherence tomography (OCT) provides accurate visualization of these features of inadequate stent deployment, whereas reduced fractional flow reserve (FFR) values after PCI indicate functional significance of a residual intrastent stenosis. OBJECTIVE: To investigate the relationship of OCT-derived intrastent lumen dimensions and FFR-derived hemodynamic relevance immediately after coronary stent implantation and to evaluate the clinical impact of these parameters at follow-up. METHODS: In 66 stable patients with a coronary de novo lesion, treated by stent implantation, post-stenting FFR and OCT data were compared and related to MACE at follow-up. RESULTS: There was a significant correlation between remaining OCT-derived intrastent percent area stenosis (%AS) and post-stent FFR (r² = 0.491; P<.001). According to receiver operating characteristic (ROC) analysis, both final FFR and intrastent %AS predicted MACE at 20 months (FFR: area under the curve [AUC] = 0.768; 95% confidence interval [CI], 0.562-0.973; and optimal cut-off = 0.905; %AS: AUC = 0.807; 95%CI, 0.613-1.000; and optimal cut-off = 16.85%) with moderate diagnostic efficiency. Intrastent %AS (16.60 ± 4.75% vs 7.01 ± 3.49%; P<.001) and the 20-month cumulative incidence of MACE (35.9% vs 5.3%; P=.01) were significantly greater in patients with FFR ≤0.905 (n = 26; 39.4%) compared with FFR >0.905 (n = 40; 60.6%). CONCLUSION: OCT-derived residual intrastent %AS is associated with decreased FFR following stent implantation and both are predictors for clinical outcome at follow-up.

Impact of type 2 diabetes mellitus and glucose control on fractional flow reserve measurements in intermediate grade coronary lesions.

BACKGROUND: Hemodynamic relevance of intermediate grade coronary stenoses is accurately assessed by fractional flow reserve (FFR) measurements. However, the reliability of FFR in patients with type 2 diabetes mellitus (DM) and inadequate glucose control (IGC) is incompletely explored. This study aimed to investigate the impact of DM and IGC on the relationship between FFR measurements and quantitative coronary angiography (QCA)-derived morphological parameters. METHODS: We performed FFR and QCA in 266 intermediate grade lesions of 224 patients (113 non-DM and 111 DM) with stable coronary artery disease. Diabetic patients were categorized into groups with adequate (HbA1C <7%) and inadequate (HbA1c ≥7%) glucose control. RESULTS: Intermediate grade lesions from all-DM versus non-DM patients differed significantly in lesion length (LL) (10.91 ± 5.79 mm versus 9.23 ± 3.85 mm, p = 0.005) and hemodynamic relevance (FFR ≤0.8, 37.7% versus 24.2%, p = 0.018). FFR measurements in non-DM, all-DM and DM-IGC patients correlated significantly with percent diameter stenosis (%DS) [non-DM: r2 = 0.075 (p = 0.007); all-DM: r2 = 0.254 (p < 0.001), DM-IGC: r2 = 0.301 (p < 0.001)] and LL [non-DM: r2 = 0.356; all-DM: r2 = 0.580, DM-IGC: r2 = 0.513 (all p < 0.001)]. There was a better correlation between FFR and both %DS (p = 0.022) and LL (p = 0.011) among all-DM compared to non-DM patients. Receiver-operating curve analysis demonstrated that among all QCA-derived parameters LL had the best diagnostic efficacy to predict FFR ≤0.8 for non-DM (AUC 0.911, 95% CI 0.861-0.960, best cut-off value 9.22 mm), all-DM (AUC 0.967, 95% CI 0.942-0.991, best cut-off value 9.97 mm) and DM-IGC (AUC 0.960, 95% CI 0.920-0.999, best cut-off value 9.97 mm) patients. CONCLUSION: Our data in intermediate grade lesions suggest that FFR is reliable in DM patients and LL is the best predictor for hemodynamic relevance in patients without and with diabetes, irrespective of the glycemic state.

Predictors and incidence of stent edge dissections in patients with type 2 diabetes as determined by optical coherence tomography.

Patients with type 2 diabetes are at increased risk for post-PCI complications including stent thrombosis and restenosis. Stent edge dissections (SEDs) have been associated with these complications. This study assessed incidence and predictors of SEDs in patients with type 2 diabetes using optical coherence tomography (OCT). Intravascular lesion parameters and plaque morphology were investigated pre- and post-PCI using OCT in 73 type 2 diabetic patients with 90 lesions and 166 visible stent edges. We detected 42 (25.3 %) SEDs in 166 stent edges and 37 (41.1 %) SEDs in 90 lesions. More SEDs occurred if the border of the stent had been placed within diseased vessel segments with predominantly fibrous (42.9 %) and fibrocalcific (40.5 %) plaques compared to healthy vessel wall morphology (p < 0.001). Furthermore, the lumen eccentricity of the stent at its edges (SAE) (16.00 ± 6.07 vs. 13.11 ± 5.22 %, p < 0.003) and the stent-edge-to-lumen-area-ratio (1.26 ± 0.27 vs. 0.99 ± 0.20, p < 0.001) were both significantly larger in the presence of SEDs. All of the above parameters were significant predictors for SEDs on uni- and multivariate logistic regression analysis (all p < 0.01), suggesting that the lumen eccentricity of the SAE, the stent-edge-to-lumen-area-ratio and diseased vessel wall morphology of the reference segment adjacent to the stent edge are independent risk factors for the presence of SEDs. These results suggest that diseased vessel wall morphology at the stent edges may promote the occurrence of SEDs and that avoidance of longitudinal and transverse mismatch between stent and vessel could be important to reduce SEDs in cardiovascular high-risk patients with type 2 diabetes.

Relationship between optical coherence tomography derived intraluminal and intramural criteria and haemodynamic relevance as determined by fractional flow reserve in intermediate coronary stenoses of patients with type 2 diabetes.

BACKGROUND: The relationship between functional relevance and optical coherence tomography (OCT)-derived measurements of coronary lesions is incompletely understood and of critical importance, particularly in cardiovascular high-risk patients with type 2 diabetes. OBJECTIVE: To investigate the association between functional relevance of intermediate grade coronary stenoses as assessed by fractional flow reserve (FFR) and OCT-derived lesion parameters in patients with diabetes. METHODS: In 46 diabetic patients with stable coronary artery disease, FFR and OCT were performed in 62 coronary lesions with intermediate severity as determined by quantitative coronary angiography. Among lesions haemodynamic relevance was defined as FFR≤0.8. RESULTS: There was a significant association between FFR and OCT-derived minimal lumen area (r(2)=0.379) and minimal lumen diameter (r(2)=0.268), all p<0.001. Receiver operating curve (ROC)-analysis demonstrated an OCT-derived minimal lumen area <1.59 mm(2) and minimal lumen diameter <1.31 mm to be optimal cut-off values to predict FFR≤0.8. Furthermore, in lipid-rich plaques FFR was significantly associated with minimal fibrous cap thickness (FCT, r(2)=0.399). Minimal FCT in lesions with FFR≤0.8 was significantly smaller (60.7±15.0 µm) compared with those lesions with FFR>0.8 (106.0±13.0 µm, p<0.001). ROC-analysis revealed that 0.81 is the ideal FFR cut-off to identify lesions with a minimal FCT≤80 µm (accuracy 97.3%, sensitivity 100%, specificity 93.8%, area under the curve 0.943 (95% CI 0.836 to 1.000)). CONCLUSIONS: Haemodynamic relevance of intermediate grade lesions in patients with type 2 diabetes is closely related to (1) intraluminal measurements, which are smaller than previously described in non-diabetic cohorts and to (2) minimal FCT. Furthermore, FFR may be useful to identify vulnerable (minimal FCT≤80 µm) lesions among those with intermediate severity in lipid-rich plaques.