Intracoronary electrocardiogram detects coronary microvascular dysfunction and ischemia in patients with no obstructive coronary arteries disease.

BACKGROUND: Coronary microvascular dysfunction (CMD) is the leading cause of ischemia with no obstructive coronary arteries disease (INOCA) disease. Diagnosis of CMD relies on surrogate physiological indices without objective proof of ischemia. OBJECTIVES: Intracoronary electrocardiogram (icECG) derived hyperemic indices may accurately and objectively detect CMD and reversible ischemia in related territory. METHODS: INOCA patients with proven ischemia by myocardial perfusion scan (MPS) and completely normal coronary arteries underwent simultaneous intracoronary electrophysiological (icECG) and physiological (intracoronary Doppler) assessment in all 3 coronary arteries during rest and under adenosine induced hyperemia. RESULTS: Sixty vessels in 21 patients were included in the final analysis. All patients had at least one vessel with abnormal CFR. 41 vessels had CMD (CFR < 2.5), of which 26 had increased microvascular resistance (structural CMD, HMR > 1.9 mmHg.cm-1.s) and 15 vessels had CMD (CFR < 2.5) with normal microvascular resistance (functional CMD, HMR <= 1.9 mmHg.cm-1.s). Only one-third of the patients (n = 7) had impaired CFR < 2.5 in all 3 epicardial arteries. Absolute ST shift between hyperemia and rest (∆ST) has shown the best diagnostic performance for ischemia (cut-off 0.10 mV, sensitivity: 95%, specificity: 72%, accuracy: 80%, AUC: 0.860) outperforming physiological indices (CFR: 0.623 and HMR: 0.653 DeLong's test P = .0002). CONCLUSIONS: In INOCA patients, CMD involves coronary artery territories heterogeneously. icECG can accurately detect CMD causing perfusion abnormalities in patients with INOCA outperforming physiological CMD markers, by demonstrating actual ischemia instead of predicting the likelihood of inducible ischemia based on violated surrogate thresholds of blunted flow reserve or increased minimum microvascular resistance. CONDENSED ABSTRACT: In 21 INOCA patients with coronary microvascular dysfunction (CMD) and myocardial perfusion scan proved ischemia, hyperemic indices of intracoronary electrocardiogram (icECG) have accurately detected vessel-specific CMD and resulting perfusion abnormalities & ischemia, outperforming invasive hemodynamic indices. Absolute ST shift between hyperemia and rest (∆ST) has shown the best classification performance for ischemia in no Obstructive Coronary Arteries (AUC: 0.860) outperforming Doppler derived CMD indices (CFR: 0.623 and HMR: 0.653 DeLong's test P = .0002).icECG can be used to diagnose CMD causing perfusion defects by demonstrating actual reversible ischemia at vessel-level during the initial CAG session, obviating the need for further costly ischemia tests. CLINICALTRIALS: GOV: NCT05471739.

Primary versus iatrogenic (post-PCI) coronary microvascular dysfunction: a wire-based multimodal comparison.

BACKGROUND: Although there are studies examining each one separately, there are no data in the literature comparing the magnitudes of the iatrogenic, percutaneous coronary intervention (PCI)-induced, microvascular dysfunction (Type-4 CMD) and coronary microvascular dysfunction (CMD) in the setting of ischaemia in non-obstructed coronary arteries (INOCA) (Type-1 CMD). OBJECTIVES: We aimed to compare the characteristics of Type-1 and Type-4 CMD subtypes using coronary haemodynamic (resistance and flow-related parameters), thermodynamic (wave energy-related parameters) and hyperemic ECG changes. METHODS: Coronary flow reserve (CFR) value of <2.5 was defined as CMD in both groups. Wire-based multimodal perfusion markers were comparatively analysed in 35 patients (21 INOCA/CMD and 14 CCS/PCI) enrolled in NCT05471739 study. RESULTS: Both groups had comparably blunted CFR values per definition (2.03±0.22 vs 2.11±0.37; p: 0.518) and similar hyperemic ST shift in intracoronary ECG (0.16±0.09 vs 0.18±0.07 mV; p: 0.537). While the Type-1 CMD was characterised with impaired hyperemic blood flow acceleration (46.52+12.83 vs 68.20+28.63 cm/s; p: 0.017) and attenuated diastolic microvascular decompression wave magnitudes (p=0.042) with higher hyperemic microvascular resistance (p<0.001), Type-4 CMD had blunted CFR mainly due to higher baseline flow velocity due to post-occlusive reactive hyperemia (33.6±13.7 vs 22.24±5.3 cm/s; p=0.003). CONCLUSIONS: The perturbations in the microvascular milieu seen in CMD in INOCA setting (Type-1 CMD) seem to be more prominent than that of seen following elective PCI (Type-4 CMD), although resulting reversible ischaemia is equally severe in the downstream myocardium.

Coronary microcirculation in nonculprit vessel territory in reperfused acute myocardial infarction.

BACKGROUND: There is an ongoing debate on the extension of reperfusion-related microvascular damage (MVD) throughout the remote noninfarcted myocardial regions in patients with ST-elevation myocardial infarction (STEMI) that undergo primary percutaneous intervention (pPCI). The aim of this study was to elucidate the impact of reperfusion on remote microcirculatory territory by analyzing hemodynamic alterations in the nonculprit-vessel in relation to reperfusion. METHODS: A total of 20 patients with STEMI undergoing pPCI were included. Peri-reperfusion temporal changes in hemodynamic parameters were obtained in angiographically normal nonculprit vessels before and 1-h after reopening of the culprit vessel. Intracoronary pressure and flow velocity data were compared using pairwise analyses (before and 1-h after reperfusion). RESULTS: In the non-culprit vessel, compared to the pre-reperfusion state, mean resting average peak velocity (33.4 ± 9.4 to 25.0 ± 4.9 cm/s, P < 0.001) and mean hyperemic average peak velocity (53.5 ± 14.4 to 42.1 ± 10.66 cm/s, P = 0.001) significantly decreased; whereas baseline (3.2 ± 1.0 to 4.0 ± 1.0 mmHg.cm-1.s, P < 0.001) and hyperemic microvascular resistance (HMR) (1.9 ± 0.6 to 2.4 ± 0.7 mmHg.cm-1.s, P < 0.001) and mean zero flow pressure (Pzf) values (32.5 ± 6.9 to 37.6 ± 8.3 mmHg, P = 0.003) significantly increased 1-h after reperfusion. In particular, the magnitude of changes in HMR and Pzf values following reperfusion were more prominent in patients with larger infarct size and with higher extent of MVD in the culprit vessel territory. CONCLUSION: Reperfusion-related microvascular injury extends to involve remote myocardial territory in relation to the magnitude of the adjacent infarction and infarct-zone MVD. (GUARD Clinical TrialsNCT02732080).

Gradual Versus Abrupt Reperfusion During Primary Percutaneous Coronary Interventions in ST-Segment-Elevation Myocardial Infarction (GUARD).

Background Intramyocardial edema and hemorrhage are key pathological mechanisms in the development of reperfusion-related microvascular damage in ST-segment-elevation myocardial infarction. These processes may be facilitated by abrupt restoration of intracoronary pressure and flow triggered by primary percutaneous coronary intervention. We investigated whether pressure-controlled reperfusion via gradual reopening of the infarct-related artery may limit microvascular injury in patients undergoing primary percutaneous coronary intervention. Methods and Results A total of 83 patients with ST-segment-elevation myocardial infarction were assessed for eligibility and 53 who did not meet inclusion criteria were excluded. The remaining 30 patients with totally occluded infarct-related artery were randomized to the pressure-controlled reperfusion with delayed stenting (PCRDS) group (n=15) or standard primary percutaneous coronary intervention with immediate stenting (IS) group (n=15) (intention-to-treat population). Data from 5 patients in each arm were unsuitable to be included in the final analysis. Finally, 20 patients undergoing primary percutaneous coronary intervention who were randomly assigned to either IS (n=10) or PCRDS (n=10) were included. In the PCRDS arm, a 1.5-mm balloon was used to achieve initial reperfusion with thrombolysis in myocardial infarction grade 3 flow and, subsequently, to control distal intracoronary pressure over a 30-minute monitoring period (MP) until stenting was performed. In both study groups, continuous assessment of coronary hemodynamics with intracoronary pressure and Doppler flow velocity was performed, with a final measurement of zero flow pressure (primary end point of the study) at the end of a 60-minute MP. There were no complications associated with IS or PCRDS. PCRDS effectively led to lower distal intracoronary pressures than IS over 30 minutes after reperfusion (71.2±9.37 mm Hg versus 90.13±12.09 mm Hg, P=0.001). Significant differences were noted between study arms in the microcirculatory response over MP. Microvascular perfusion progressively deteriorated in the IS group and at the end of MP, and hyperemic microvascular resistance was significantly higher in the IS arm as compared with the PCDRS arm (2.83±0.56 mm Hg.s.cm-1 versus 1.83±0.53 mm Hg.s.cm-1, P=0.001). The primary end point (zero flow pressure) was significantly lower in the PCRDS group than in the IS group (41.46±17.85 mm Hg versus 76.87±21.34 mm Hg, P=0.001). In the whole study group (n=20), reperfusion pressures measured at predefined stages in the early reperfusion period showed robust associations with zero flow pressure values measured at the end of the 1-hour MP (immediately after reperfusion: r=0.782, P<0.001; at the 10th minute: r=0.796, P<0.001; and at the 20th minute: r=0.702, P=0.001) and peak creatine kinase MB level (immediately after reperfusion: r=0.653, P=0.002; at the 10th minute: r=0.597, P=0.007; and at the 20th minute: r=0.538, P=0.017). Enzymatic myocardial infarction size was lower in the PCRDS group than in the IS group with peak troponin T (5395±2991 ng/mL versus 8874±1927 ng/mL, P=0.006) and creatine kinase MB (163.6±93.4 IU/L versus 542.2±227.4 IU/L, P<0.001). Conclusions In patients with ST-segment-elevation myocardial infarction, pressure-controlled reperfusion of the culprit vessel by means of gradual reopening of the occluded infarct-related artery (PCRDS) led to better-preserved coronary microvascular integrity and smaller myocardial infarction size, without an increase in procedural complications, compared with IS. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02732080.

Intracardiac masses: Single center experience within 12 years: I-MASS Study.

Objective: The aim of this cross-sectional, retrospective, descriptive study was to review and classify cardiac masses systematically and to determine their frequencies. Methods: The medical records of 64,862 consecutive patients were investigated within 12 years. Every patient with a cardiac mass imaged by transthoracic echocardiography (TTE) and confirmed with an advanced imaging modality such as transesophageal echocardiography (TEE), computed tomography (CT) and/or cardiac magnetic resonance imaging (CMR) was included. Acute coronary syndromes triggering thrombus formation, vegetations, intracardiac device and catheter related thrombi were excluded. Results: Data demonstrated 127 (0.195%) intracardiac masses consisting of 33 (0.050%) primary benign, 3 (0.004%) primary malignant, 20 (0.030%) secondary tumors, 3 (0.004%) hydatid cysts and 68 (0.104%) thrombi respectively. The majority of primary cardiac tumors were benign (91.67%), predominantly myxomas (78.79%), and the less malignant (8.33%). Secondary cardiac tumors were common than the primary malignant tumors (20:3), with male dominancy (55%), lymphoma and lung cancers were the most frequent. Intracardiac thrombi was the majority of the cardiac masses, thrombi accompanying malignancies were in the first range (n = 17, 25%), followed by autoimmune diseases (n = 13, 19.12%) and ischemic heart disease with low ejection fraction (n = 12, 17.65%). Conclusions: This retrospective analysis identified 127 patients with cardiac masses. The majority of benign tumors were myxoma, the most common tumors that metastasized to the heart were lymphoma and lung cancers, and the thrombi associated with malignancies and autoimmune diseases were the most frequent.

The Interplay between Features of Plaque Vulnerability and Hemodynamic Relevance of Coronary Artery Stenoses.

Fractional flow reserve (FFR) may not be immune from hemodynamic perturbations caused by both vessel and lesion related factors. The aim of this study was to investigate the impact of plaque- and vessel wall-related features of vulnerability on the hemodynamic effect of intermediate coronary stenoses. Methods and Results: In this cross-sectional study, patients referred to catheterization laboratory for clinically indicated coronary angiography were prospectively screened for angiographically intermediate stenosis (50-80%). Seventy lesions from 60 patients were evaluated. Mean angiographic stenosis was 62.1 ± 16.3%. After having performed FFR assessment, intravascular ultrasound (IVUS) was performed over the FFR wire. Virtual histology IVUS was used to identify the plaque components and thin cap fibroatheroma (TCFA). TCFA was significantly more frequent (65 vs. 38%, p = 0.026), and necrotic core volume (26.15 ± 14.22 vs. 16.21 ± 8.93 mm3, p = 0.04) was significantly larger in the positively remodeled than non-remodeled vessels. Remodeling index correlated with necrotic core volume (r = 0.396, p = 0.001) and with FFR (r = -0. 419, p = 0.001). With respect to plaque components, only necrotic core area (r = -0.262, p = 0.038) and necrotic core volume (r = -0.272, p = 0.024) were independently associated with FFR. In the multivariable model, presence of TCFA was independently associated with significantly lower mean FFR value as compared to absence of TCFA (adjusted, 0.71 vs. 0.78, p = 0.034). Conclusion: The current study demonstrated that for a given stenosis geometry, features of plaque vulnerability such as necrotic core volume, TCFA, and positive remodeling may influence the hemodynamic relevance of intermediate coronary stenoses.

Validation of the adjusted global antiphospholipid syndrome score in a single centre cohort of APS patients from Turkey.

The adjusted global antiphospholipid syndrome score (aGAPSS) is a recently developed thrombotic risk assessment score that considers the antiphospholipid antibody (aPL) profile and conventional cardiovascular risk factors. In this retrospective study, we aimed to evaluate the validity of the aGAPSS in predicting clinical manifestations (criteria and extra-criteria) of antiphospholipid syndrome (APS) in a single centre cohort of patients. Ninety-eight patients with APS ± systemic lupus erythematosus (SLE) were classified according to clinical manifestations as vascular thrombosis (VT), pregnancy morbidity (PM) or both (VT + PM). The aGAPSS was calculated for each patient as previously defined. Mean aGAPSS of the cohort was calculated as 10.2 ± 3.8. Significantly higher aGAPSS values were seen in VT (n = 58) and VT + PM (n = 29) groups when compared to PM (n = 11) group (10.6 ± 3.7 vs 7.4 ± 2.9, P = 0.005; 10.7 ± 4 vs 7.4 ± 2.9, P = 0.008, respectively), mainly due to lower frequencies of cardiovascular risk factors in PM. Higher aGAPPS values were also associated with recurrent thrombosis (11.6 ± 3.7 vs 9.9 ± 3.6, P = 0.04). Regarding extra-criteria manifestations, patients with livedo reticularis (n = 11) and APS nephropathy (n = 9) had significantly higher aGAPSS values (12.9 ± 3.4 vs 9.9 ± 3.7, P = 0.02; 12.4 ± 2.9 vs 10 ± 3.8, P = 0.04, respectively). The computed AUC demonstrated that aGAPSS values ≥10 had the best diagnostic accuracy for thrombosis. Our results suggest that patients with higher aGAPSS values are at higher risk for developing vascular thrombosis (either first event or recurrence) and extra-criteria manifestations, especially livedo reticularis and APS nephropathy.

Reducing Aortic Barotrauma and Vascular Extracellular Matrix Degradation by Pacemaker-Mediated QRS Widening.

Background The extent of pressure-related damage might be related to acceleration rate of the applied pressure (peak dP/dt) in the vascular system. In this study, we sought to determine whether dP/dt applied to the aortic wall (aortic dP/dt) and in turn vascular extracellular matrix degradation can be mitigated via modulation of left ventricular (LV) contractility (LV dP/dt) by pacemaker-mediated desynchronization. Methods and Results First, in 34 patients, changes in aortic dP/dt values in 3 aortic segments in response to pacemaker-mediated stepwise QRS widening leading to gradual desynchronization of the LV contraction by means of steadily changed atrioventricular delay (AVD) with temporary dual-chamber pacing was examined before and after beta-blocker (15 mg IV metoprolol) administration. Second, serum matrix metalloproteinase-9 levels were measured in the 20 patients with permanent pacemaker while they were on sinus rhythm with normal QRS width and 3 weeks after wide QRS rhythm ensured by dual pacing, dual sensing, and dual response to sensing with short AVD. LV dP/dt substantially correlated with dP/dt measured in ascending (r=0.83), descending (r=0.89), and abdominal aorta (r=0.96). QRS width strongly correlated with dP/dt measured in ascending (r=-0.95), descending (r=-0.92), and abdominal (r=-0.96) aortic segments as well. In patients with permanent pacemaker, wide QRS rhythm led to a significant reduction in serum matrix metalloproteinase-9 levels (from 142.5±32.9 pg/mL to 87.5±32.4 pg/mL [P<0.001]) at the end of 3 weeks follow-up. Conclusions QRS prolongation by short AVD dual pacing, dual sensing, and dual response to sensing results in concomitant decreases in peak dP/dt values in the LV and in all aortic segments with or without background beta-blocker administration, which in turn led to a significant reduction in circulating matrix metalloproteinase-9 levels. Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT03665558.

Sex Differences in Instantaneous Wave-Free Ratio or Fractional Flow Reserve-Guided Revascularization Strategy.

OBJECTIVES: This study sought to evaluate sex differences in procedural characteristics and clinical outcomes of instantaneous wave-free ratio (iFR)- and fractional flow reserve (FFR)-guided revascularization strategies. BACKGROUND: An iFR-guided strategy has shown a lower revascularization rate than an FFR-guided strategy, without differences in clinical outcomes. METHODS: This is a post hoc analysis of the DEFINE-FLAIR (Functional Lesion Assessment of Intermediate stenosis to guide Revascularization) study, in which 601 women and 1,891 men were randomized to iFR- or FFR-guided strategy. The primary endpoint was 1-year major adverse cardiac events (MACE), a composite of all-cause death, nonfatal myocardial infarction, or unplanned revascularization. RESULTS: Among the entire population, women had a lower number of functionally significant lesions per patient (0.31 ± 0.51 vs. 0.43 ± 0.59; p < 0.001) and less frequently underwent revascularization than men (42.1% vs. 53.1%; p < 0.001). There was no difference in mean iFR value according to sex (0.91 ± 0.09 vs. 0.91 ± 0.10; p = 0.442). However, the mean FFR value was lower in men than in women (0.83 ± 0.09 vs. 0.85 ± 0.10; p = 0.001). In men, an FFR-guided strategy was associated with a higher rate of revascularization than an iFR-guided strategy (57.1% vs. 49.3%; p = 0.001), but this difference was not observed in women (41.4% vs. 42.6%; p = 0.757). There was no difference in MACE rates between iFR- and FFR-guided strategies in both women (5.4% vs. 5.6%, adjusted hazard ratio: 1.10; 95% confidence interval: 0.50 to 2.43; p = 0.805) and men (6.6% vs. 7.0%, adjusted hazard ratio: 0.98; 95% confidence interval: 0.66 to 1.46; p = 0.919). CONCLUSIONS: An FFR-guided strategy was associated with a higher rate of revascularization than iFR-guided strategy in men, but not in women. However, iFR- and FFR-guided strategies showed comparable clinical outcomes, regardless of sex. (Functional Lesion Assessment of Intermediate Stenosis to guide Revascularization [DEFINE-FLAIR]; NCT02053038).

Comparison of Major Adverse Cardiac Events Between Instantaneous Wave-Free Ratio and Fractional Flow Reserve-Guided Strategy in Patients With or Without Type 2 Diabetes: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Invasive physiologic indices such as fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are used in clinical practice. Nevertheless, comparative prognostic outcomes of iFR-guided and FFR-guided treatment in patients with type 2 diabetes have not yet been fully investigated. Objective: To compare 1-year clinical outcomes of iFR-guided or FFR-guided treatment in patients with and without diabetes in the Functional Lesion Assessment of Intermediate Stenosis to Guide Revascularization (DEFINE-FLAIR) trial. Design, Setting, and Participants: The DEFINE-FLAIR trial is a multicenter, international, randomized, double-blinded trial that randomly assigned 2492 patients in a 1:1 ratio to undergo either iFR-guided or FFR-guided coronary revascularization. Patients were eligible for trial inclusion if they had intermediate coronary artery disease (40%-70% diameter stenosis) in at least 1 native coronary artery. Data were analyzed between January 2014 and December 2015. Interventions: According to the study protocol, iFR of 0.89 or less and FFR of 0.80 or less were used as criteria for revascularization. When iFR or FFR was higher than the prespecified threshold, revascularization was deferred. Main Outcomes and Measures: The primary end point was major adverse cardiac events (MACE), defined as the composite of all-cause death, nonfatal myocardial infarction, or unplanned revascularization at 1 year. The incidence of MACE was compared according to the presence of diabetes in iFR-guided and FFR-guided groups. Results: Among the total trial population (2492 patients), 758 patients (30.4%) had diabetes. Mean age of the patients was 66 years, 76% were men (1868 of 2465), and 80% of patients presented with stable angina (1983 of 2465). In the nondiabetes population (68.5%; 1707 patients), iFR guidance was associated with a significantly higher rate of deferral of revascularization than the FFR-guided group (56.5% [n = 477 of 844] vs 46.6% [n = 402 of 863]; P < .001). However, it was not different between the 2 groups in the diabetes population (42.1% [n = 161 of 382] vs 47.1% [n = 177 of 376]; P = .15). At 1 year, the diabetes population showed a significantly higher rate of MACE than the nondiabetes population (8.6% vs 5.6%; adjusted hazard ratio [HR], 1.88; 95% CI, 1.28-2.64; P < .001). However, there was no significant difference in MACE rates between iFR-guided and FFR-guided groups in both the diabetes (10.0% vs 7.2%; adjusted HR, 1.33; 95% CI, 0.78-2.25; P = .30) and nondiabetes population (4.7% vs 6.4%; HR, 0.83; 95% CI, 0.51-1.35; P = .45) (interaction P = .25). Conclusions and Relevance: The diabetes population showed significantly higher risk of MACE than the nondiabetes population, even with the iFR-guided or FFR-guided treatment. The iFR-guided and FFR-guided treatment showed comparable risk of MACE and provided equal safety in selecting revascularization target among patients with diabetes. Trial Registration: ClinicalTrials.gov identifier: NCT02053038.

Clinical Events After Deferral of LAD Revascularization Following Physiological Coronary Assessment.

BACKGROUND: Physicians are not always comfortable deferring treatment of a stenosis in the left anterior descending (LAD) artery because of the perception that there is a high risk of major adverse cardiac events (MACE). The authors describe, using the DEFINE-FLAIR (Functional Lesion Assessment of Intermediate Stenosis to Guide Revascularisation) trial, MACE rates when LAD lesions are deferred, guided by physiological assessment using fractional flow reserve (FFR) or the instantaneous wave-free ratio (iFR). OBJECTIVES: The purpose of this study was to establish the safety of deferring treatment in the LAD using FFR or iFR within the DEFINE-FLAIR trial. METHODS: MACE rates at 1 year were compared between groups (iFR and FFR) in patients whose physiological assessment led to LAD lesions being deferred. MACE was defined as a composite of cardiovascular death, myocardial infarction (MI), and unplanned revascularization at 1 year. Patients, and staff performing follow-up, were blinded to whether the decision was made with FFR or iFR. Outcomes were adjusted for age and sex. RESULTS: A total of 872 patients had lesions deferred in the LAD (421 guided by FFR, 451 guided by iFR). The event rate with iFR was significantly lower than with FFR (2.44% vs. 5.26%; adjusted HR: 0.46; 95% confidence interval [CI]: 0.22 to 0.95; p = 0.04). This was driven by significantly lower unplanned revascularization with iFR and numerically lower MI (unplanned revascularization: 2.22% iFR vs. 4.99% FFR; adjusted HR: 0.44; 95% CI: 0.21 to 0.93; p = 0.03; MI: 0.44% iFR vs. 2.14% FFR; adjusted HR: 0.23; 95% CI: 0.05 to 1.07; p = 0.06). CONCLUSIONS: iFR-guided deferral appears to be safe for patients with LAD lesions. Patients in whom iFR-guided deferral was performed had statistically significantly lower event rates than those with FFR-guided deferral.

Glycoprotein Ibα Kozak polymorphism in patients presenting with early-onset acute coronary syndrome.

INTRODUCTION: Glycoprotein Ibα (GPIbα) receptor is the chief molecule responsible for initial platelet adhesion to the subendothelium. A thymidine to cytosine single nucleotide substitution at position -5 from the ATG start codon characterizes the Kozak sequence polymorphism. The Kozak sequence polymorphism may increase the surface expression of GPIbα and contribute to thrombogenesis. We evaluated the allele frequencies of GPIbα Kozak sequence polymorphism in the Turkish population and examined the relationship between GPIbα Kozak sequence polymorphism and early-onset acute coronary syndrome (ACS). MATERIAL AND METHODS: This study enrolled 200 patients (122 male, 78 female, mean age: 39 ±5 years) and 200 healthy control subjects (110 male, 90 female, 41 ±4 years). The patient group was composed of patients admitted to our coronary care unit with early-onset ACS and patients who attended to our cardiology outpatient clinic after hospital discharge with a diagnosis of early-onset ACS. RESULTS: Kozak polymorphism frequencies in patients and control subjects did not differ significantly (23% versus 22.5%, p = 0.812, respectively). In patients who presented with non-ST elevation myocardial infarction (NSTEMI), the frequency of GPIbα Kozak polymorphism was borderline significantly higher when compared with patients who presented with ST elevation myocardial infarction (STEMI) (35% vs. 20%, p = 0.05, respectively). Allele frequencies of T and C were calculated to be 0.873 and 0.128. CONCLUSIONS: Although the frequency of GPIbα Kozak polymorphism did not differ significantly in early-onset ACS patients versus control subjects, Kozak polymorphism frequency was borderline significantly higher in patients who presented with NSTEMI when compared to patients with STEMI.

Spectroelectrochemical insights into structural and redox properties of immobilized endonuclease III and its catalytically inactive mutant.

Endonuclease III is a Fe-S containing bifunctional DNA glycosylase which is involved in the repair of oxidation damaged DNA. Here we employ surface enhanced IR spectroelectrochemistry and electrochemistry to study the enzyme from the highly radiation- and desiccation-resistant bacterium Deinococcus radiodurans (DrEndoIII2). The experiments are designed to shed more light onto specific parameters that are currently proposed to govern damage search and recognition by endonucleases III. We demonstrate that electrostatic interactions required for the redox activation of DrEndoIII2 may result in high electric fields that alter its structural and thermodynamic properties. Analysis of inactive DrEndoIII2 (K132A/D150A double mutant) interacting with undamaged DNA, and the active enzyme interacting with damaged DNA also indicate that the electron transfer is modulated by subtle differences in the protein-DNA complex.

Hyperaemic microvascular resistance predicts clinical outcome and microvascular injury after myocardial infarction.

OBJECTIVES: Early detection of microvascular dysfunction after acute myocardial infarction (AMI) could identify patients at high risk of adverse clinical outcome, who may benefit from adjunctive treatment. Our objective was to compare invasively measured coronary flow reserve (CFR) and hyperaemic microvascular resistance (HMR) for their predictive power of long-term clinical outcome and cardiac magnetic resonance (CMR)-defined microvascular injury (MVI). METHODS: Simultaneous intracoronary Doppler flow velocity and pressure measurements acquired immediately after revascularisation for AMI from five centres were pooled. Clinical follow-up was completed for 176 patients (mean age 60±10 years; 140(80%) male; ST-elevation myocardial infarction (STEMI) 130(74%) and non-ST-segment elevation myocardial infarction 46(26%)) with median follow-up time of 3.2 years. In 110 patients with STEMI, additional CMR was performed. RESULTS: The composite end point of death and hospitalisation for heart failure occurred in 17 patients (10%). Optimal cut-off values to predict the composite end point were 1.5 for CFR and 3.0 mm Hg cm-1•s for HMR. CFR <1.5 was predictive for the composite end point (HR 3.5;95% CI 1.1 to 10.8), but not for its individual components. HMR ≥3.0 mm Hg cm-1 s was predictive for the composite end point (HR 7.0;95% CI 1.5 to 33.7) as well as both individual components. HMR had significantly greater area under the receiver operating characteristic curve for MVI than CFR. HMR remained an independent predictor of adverse clinical outcome and MVI, whereas CFR did not. CONCLUSIONS: HMR measured immediately following percutaneous coronary intervention for AMI with a cut-off value of 3.0 mm Hg cm-1 s, identifies patients with MVI who are at high risk of adverse clinical outcome. For this purpose, HMR is superior to CFR.

Influence of coronary calcification patterns on hemodynamic outcome of coronary stenoses and remodeling.

OBJECTIVE: The histological characteristics of plaque may affect the hemodynamic outcome of a given coronary stenosis. In particular, the potential effect of volumetric calcium content and the topographical distribution in the lesion segment on physiological outcome has not yet been investigated. The aim of this study was to identify any potential correlation between patterns of calcification and the fractional flow reserve (FFR) and the coronary remodeling index (RMI). METHODS: A total of 26 stable angina pectoris and 34 acute coronary syndrome patients without persistent ST-segment elevation constituted the study population. FFR was used to assess 70 intermediate coronary stenosis lesions. After obtaining hemodynamic measurements, quantitative grayscale and virtual histology-intravascular ultrasound analyses were performed. The depth, length, and circumferential distribution of calcification of the lesions were also recorded. RESULTS: Within the analyzed segment (area of interest, lesion segment), FFR was correlated with maximal thickness of deep calcification (r=-0.285; p=0.021) and calcification angle (r=-0.396; p=0.001). In lesions with a calcification angle >180°, the mean FFR value was significantly lower compared with those <180° (0.64±0.17 vs. 0.78±0.08; p=0.024). RMI was correlated with maximal angle of superficial (r=-0.437; p<0.001) and deep (r=0.425; p<0.001) calcification. RMI was correlated with maximal thickness of superficial (r=-0.357; p=0.003) and deep (r=0.417; p<0.001) calcification. RMI was also correlated with FFR (r=-0.477; p<0.001). CONCLUSION: This study demonstrated that the geometry, location, and amount of calcification of a plaque could affect hemodynamic and anatomical outcome measures in functionally significant stenoses by affecting vessel wall compliance.

Invasive Assessment of the Coronary Microcirculation in Reperfused ST-Segment-Elevation Myocardial Infarction Patients: Where Do We Stand?

For patients presenting with an acute ST-segment-elevation myocardial infarction, the most effective therapy for reducing myocardial infarct size and preserving left ventricular systolic function is primary percutaneous coronary intervention (PPCI). However, mortality and morbidity remain significant. This is partly attributed to the development of microvascular obstruction, which occurs in around 50% of ST-segment-elevation myocardial infarction patients post-PPCI, and it is associated with adverse left ventricular remodeling and worse clinical outcomes. Although microvascular obstruction can be detected by cardiac imaging techniques several hours post-PPCI, it may be too late to intervene at that time. Therefore, being able to predict the development of microvascular obstruction at the time of PPCI may identify high-risk patients who might benefit from further adjuvant intracoronary therapies, such as thrombolysis, vasodilators, glycoprotein IIb/IIIa inhibitors, and anti-inflammatory agents that may reduce microvascular obstruction. Recent studies have shown that invasive coronary physiology measurements performed during PPCI can be used to assess the coronary microcirculation. In this article, we provide an overview of the various invasive methods currently available to assess the coronary microcirculation in the setting of ST-segment-elevation myocardial infarction, and how they could potentially be used in the future for tailoring therapies to those most at risk.