Vitamin K-antagonists accelerate atherosclerotic calcification and induce a vulnerable plaque phenotype.

BACKGROUND: Vitamin K-antagonists (VKA) are treatment of choice and standard care for patients with venous thrombosis and thromboembolic risk. In experimental animal models as well as humans, VKA have been shown to promote medial elastocalcinosis. As vascular calcification is considered an independent risk factor for plaque instability, we here investigated the effect of VKA on coronary calcification in patients and on calcification of atherosclerotic plaques in the ApoE(-/-) model of atherosclerosis. METHODOLOGY/PRINCIPAL FINDINGS: A total of 266 patients (133 VKA users and 133 gender and Framingham Risk Score matched non-VKA users) underwent 64-slice MDCT to assess the degree of coronary artery disease (CAD). VKA-users developed significantly more calcified coronary plaques as compared to non-VKA users. ApoE(-/-) mice (10 weeks) received a Western type diet (WTD) for 12 weeks, after which mice were fed a WTD supplemented with vitamin K(1) (VK(1), 1.5 mg/g) or vitamin K(1) and warfarin (VK(1)&W; 1.5 mg/g & 3.0 mg/g) for 1 or 4 weeks, after which mice were sacrificed. Warfarin significantly increased frequency and extent of vascular calcification. Also, plaque calcification comprised microcalcification of the intimal layer. Furthermore, warfarin treatment decreased plaque expression of calcification regulatory protein carboxylated matrix Gla-protein, increased apoptosis and, surprisingly outward plaque remodeling, without affecting overall plaque burden. CONCLUSIONS/SIGNIFICANCE: VKA use is associated with coronary artery plaque calcification in patients with suspected CAD and causes changes in plaque morphology with features of plaque vulnerability in ApoE(-/-) mice. Our findings underscore the need for alternative anticoagulants that do not interfere with the vitamin K cycle.

Performance of angiographic, electrocardiographic and MRI methods to assess the area at risk in acute myocardial infarction.

Objective Validation of methods to assess the area at risk (AAR) in patients with ST elevation myocardial infarction is limited. A study was undertaken to test different AAR methods using established physiological concepts to provide a reference standard. Main outcome measured In 78 reperfused patients with first ST elevation myocardial infarction, AAR was measured by electrocardiographic (Aldrich), angiographic (Bypass Angioplasty Revascularization Investigation (BARI), APPROACH) and cardiovascular magnetic resonance methods (T2-weighted hyperintensity and delayed enhanced endocardial surface area (ESA)). The following established physiological concepts were used to evaluate the AAR METHODS: (1) AAR size is always ≥ infarct size (IS); (2) in transmural infarcts AAR size=IS; (3) correlation between AAR size and IS increases as infarct transmurality increases; and (4) myocardial salvage ((AAR-IS)/AAR×100) is inversely related to infarct transmurality. Results Overall, 65%, 87%, 76%, 87% and 97% of patients using the Aldrich, BARI, APPROACH, T2-weighted hyperintensity and ESA methods obeyed the concept that AAR size is ≥IS. In patients with transmural infarcts (n=22), Bland-Altman analysis showed poor agreement (wide 95% limits of agreement) between AAR size and IS for the BARI, Aldrich and APPROACH methods (95% CI -22.9 to 29.6, 95% CI -28.3 to 21.3 and 95% CI -16.9 to 20.0, respectively) and better agreement for T2-weighted hyperintensity and ESA (95% CI -6.9 to 16.6 and 95% CI -4.3 to 18.0, respectively). Increasing correlation between AAR size and IS with increasing infarct transmurality was observed for the APPROACH, T2-weighted hyperintensity and ESA methods, with ESA having the highest correlation (r=0.93, p<0.001). The percentage of patients within a narrow margin (±30%) of the inverse line of identity between salvage extent and infarct transmurality was 56%, 76%, 65%, 77% and 92% for the Aldrich, BARI, APPROACH, T2-weighted hyperintensity and ESA methods, respectively, where higher percentages represent better concordance with the concept that the extent of salvage should be inversely related to infarct transmurality. Conclusions For measuring AAR, cardiovascular magnetic resonance methods are better than angiographic methods, which are better than electrocardiographic methods. Overall, ESA performed best for measuring AAR in vivo.

The extent of coronary atherosclerosis is associated with increasing circulating levels of high sensitive cardiac troponin T.

OBJECTIVE: This study explored the relationship between coronary atherosclerotic plaque burden and quantifiable circulating levels of troponin measured with a recently introduced high sensitive cardiac troponin T (hs-cTnT) assay. METHODS AND RESULTS: Cardiac patients suspected of having coronary artery disease (CAD) but without acute coronary syndrome were studied. Cardiac troponin T levels were assessed using the fifth-generation hs-cTnT assay. All patients (n=615) underwent cardiac computed tomographic angiography (CCTA). On the basis of CCTA, patients were classified as having no CAD or mild (<50% lesion), moderate (50% to 70% lesion), severe (>70% lesion), or multivessel CAD (multiple >70% lesions). As a comparison, high-sensitivity C-reactive protein levels were measured. Progressively increasing hs-cTnT levels were found in patients with mild (median, 4.5 ng/L), moderate (median, 5.5 ng/L), severe (median, 5.7 ng/L), and multivessel (median, 8.6 ng/L) CAD compared with patients without CAD (median, 3.7 ng/L) (all P<0.01). For high-sensitivity C-reactive protein and N-terminal pro-B-type natriuretic peptide, no such relationship was observed. In patients without CAD, 11% showed hs-cTnT levels in the highest quartile, compared with 62% in the multivessel disease group (P<0.05). Multivariance analysis identified hs-cTnT as an independent risk factor for the presence of CAD. CONCLUSIONS: In patients without acute coronary syndrome, even mild CAD is associated with quantifiable circulating levels of hs-cTnT.

Noninvasive assessment of arterial stiffness should discriminate between systolic and diastolic pressure ranges.

Arterial stiffening plays an important role in the development of hypertension and cardiovascular diseases. The intrinsically nonlinear (ie, pressure-dependent) elastic behavior of arteries may have serious consequences for the accuracy and interpretation of arterial stiffness measurements and, ultimately, for individual patient management. We determined aortic pressure and common carotid artery diameter waveforms in 21 patients undergoing cardiac catheterization. The individual pressure-area curves were described using a dual exponential analytic model facilitating noise-free calculation of incremental pulse wave velocity. In addition, compliance coefficients were calculated separately in the diastolic and systolic pressure ranges, only using diastolic, dicrotic notch, and systolic data points, which can be determined noninvasively. Pulse wave velocity at systolic pressure exhibited a much stronger positive correlation with pulse pressure (P<0.001) and age (P=0.012) than pulse wave velocity at diastolic pressure. Patients with an elevated systolic blood pressure (>140 mm Hg) had a 2.5-times lower compliance coefficient in the systolic pressure range than patients with systolic blood pressures <140 mm Hg (P=0.002). Most importantly, some individuals, with comparable age or pulse pressure, had similar diastolic but discriminately different systolic pulse wave velocities and compliance coefficients. We conclude that noninvasive assessment of arterial stiffness could and should discriminate between systolic and diastolic pressure ranges to more precisely characterize arterial function in individual patients.

Molecular imaging of macrophage cell death for the assessment of plaque vulnerability.

The ability to identify atherosclerotic plaques that are prone to rupture, also called vulnerable plaques, may provide a major step forward in the recognition of patients that have a high risk of developing acute myocardial infarction. Current clinical risk profiling algorithms, such as the Framingham and Procam risk scores, have reasonable predictive value in the assessment of the 10 year risk. These clinical risk profiling scores typically classify patients into low risk (10-year risk, less than 5%), intermediate risk (5% to 20% risk), and high risk (greater than 20%). The challenge to imagers is to identify the risk that is beyond 2% yearly risk. Molecular imaging may help identify plaque inflammation and apoptosis of inflammatory cells, which are obligatory components of the plaque instability. These processes offer specific biological targets that can potentially be exploited to obtain biological information on atherosclerosis development in the individual patient.