Prevalence and Impact of Frailty in Patients ≥70 Years Old with Acute Coronary Syndrome Referred for Coronary Angiography.

INTRODUCTION: Elderly patients with acute coronary syndrome (ACS) have a higher risk of adverse cardiovascular events and may be frail but are underrepresented in clinical trials. Previous studies have proposed that frailty assessment is a better tool than chronological age, in assessing older patients' biological age, and may exceed conventional risk scores in predicting the prognosis. Therefore, we wanted to investigate the prevalence and impact on 12-month outcomes of frailty in patients ≥70 years with ACS referred for coronary angiography (CAG). METHODS: Patients ≥70 years with ACS referred for CAG underwent frailty scoring with the clinical frailty scale (CFS). Patients were divided into three groups depending on their CFS: robust (1-3), vulnerable (4), and frail (5-9) and followed for 12 months. RESULTS: Of 455 patients, 69 (15%) patients were frail, 79 (17%) were vulnerable, and 307 (68%) were robust. Frail patients were older (frail: 80.9 ± 5.7 years, vulnerable: 78.5 ± 5.5 years, and robust: 76.6 ± 4.9 years, p < 0.001) and less often treated with percutaneous coronary intervention (frail: 56.5%, vulnerable: 53.2%, and robust: 68.6%, p = 0.014). 12-month mortality was higher among frail patients (frail: 24.6%, vulnerable: 21.8%, and robust: 6.2%, p < 0.001). Frailty was associated with a higher mortality after adjustment for age, sex, comorbidities, the Global Registry of Acute Coronary Events (GRACE) score, and revascularisation (HR 2.67, 95% CI 1.30-5.50, p = 0.008). There was no difference between GRACE and CFS in predicting 12-month mortality (p = 0.893). CONCLUSIONS: Fifteen percent of patients ≥70 years old with ACS referred for CAG are frail. Frail patients have significantly higher 12-month mortality. GRACE and CFS are similar in predicting 12-month mortality.

Coronary CT and timing of invasive coronary angiography in patients ≥75 years old with non-ST segment elevation acute coronary syndromes.

BACKGROUND: The ability of coronary CT angiography (cCTA) to rule out significant coronary artery disease (CAD) in older patients with non-ST segment elevation acute coronary syndromes (NSTEACS) is unclear since valid cCTA analysis may be limited by extensive coronary artery calcification. In addition, the effect of very early invasive coronary angiography (ICA) with possible revascularisation is debated. METHODS: This is a posthoc analysis of patients ≥75 years included in the Very Early vs Standard Care Invasive Examination and Treatment of Patients with Non-ST-Segment Elevation Acute Coronary Syndrome Trial. cCTA was performed prior to the ICA. The diagnostic accuracy of cCTA was investigated. Presence of a coronary artery stenosis ≥50% by subsequent ICA was used as reference. Patients were randomised to a very early (within 12 hours of diagnosis) or a standard ICA (within 48-72 hours of diagnosis). The primary composite endpoint was 5-year all-cause mortality, non-fatal recurrent myocardial infarction or hospital admission for refractory myocardial ischaemia or heart failure. RESULTS: Of 452 (21%) patients ≥75 years, 161 (35.6%) underwent cCTA. 19% of cCTAs excluded significant CAD. The negative predictive value (NPV) of cCTA was 94% (95% CI 79 to 99) and the sensitivity 98% (95% CI 94 to 100). No significant differences in the frequency of primary endpoints were seen in patients randomised to very early ICA (at 5-year follow-up, n=100 (46.9%) vs 122 (51.0%), log-rank p=0.357). CONCLUSION: In patients ≥75 years with NSTEACS, cCTA before ICA showed a high NPV. A very early ICA <12 hours of diagnosis did not significantly improve long-term clinical outcomes.

Microcirculatory Function in Nonhypertrophic and Hypertrophic Myocardium in Patients With Aortic Valve Stenosis.

Background Left ventricular hypertrophy (LVH) has often been supposed to be associated with abnormal myocardial blood flow and resistance. The aim of this study was to evaluate and quantify the physiological and pathological changes in myocardial blood flow and microcirculatory resistance in patients with and without LVH attributable to severe aortic stenosis. Methods and Results Absolute coronary blood flow and microvascular resistance were measured using a novel technique with continuous thermodilution and infusion of saline. In addition, myocardial mass was assessed with cardiac magnetic resonance imaging. Fifty-three patients with aortic valve stenosis were enrolled in the study. In 32 patients with LVH, hyperemic blood flow per gram of tissue was significantly decreased compared with 21 patients without LVH (1.26±0.48 versus 1.66±0.65 mL·min-1·g-1; P=0.018), whereas minimal resistance indexed for left ventricular mass was significantly increased in patients with LVH (63 [47-82] versus 43 [35-63] Wood Units·kg; P=0.014). Conclusions Patients with LVH attributable to severe aortic stenosis had lower hyperemic blood flow per gram of myocardium and higher minimal myocardial resistance compared with patients without LVH.

Is It Safe to Mobilize Patients Very Early After Transfemoral Coronary Procedures? (SAMOVAR): A Randomized Clinical Trial.

BACKGROUND: Coronary angiography (CAG) and percutaneous coronary intervention (PCI) are performed via the femoral or radial arteries. In patients examined via transfemoral access, closure devices facilitate hemostasis, but it is unknown whether it is safe to mobilize these patients immediately and how acceptable this may be in terms of patient comfort. OBJECTIVE: The aims of this study were to investigate bleeding complications in patients mobilized immediately after transfemoral CAG or PCI compared with patients on bed rest (BR) for 2 hours after the procedure and, furthermore, to investigate patient comfort in relation to mobilization and BR. METHODS: SAMOVAR was a noninferiority trial with patients randomized to immediate mobilization (IM) or 2 hours of BR after transfemoral CAG or PCI and use of the AngioSeal as a closure device and reversal of heparin effect. The primary end point was development of hematoma greater than 5 cm, pseudoaneurysm, or bleeding requiring blood transfusion. Secondary end points were oozing from the puncture site, small hematoma, and patient comfort. RESULTS: Of 2027 patients (IM, 1010; BR, 1017), 40% underwent PCI. The primary outcome was recorded in 0.7% patients randomized to IM versus 0.5% in BR ( P = .58). There was no difference in the incidence of small hematoma, whereas persistent oozing was seen slightly more often after IM compared with BR (12% vs 9%, P = .04). Patients mobilized immediately reported less back pain and micturition problems ( P < .001). CONCLUSIONS: In patients who had CAG and PCI performed through transfemoral access, reversal of anticoagulation and use of closure devices allowed IM with low rates of complications and improved patient comfort.

Outcome in Elderly Patients With Cardiogenic Shock Complicating Acute Myocardial Infarction.

INTRODUCTION: Despite advances in treatment of patients with cardiogenic shock following acute myocardial infarction (AMICS) in-hospital mortality remains around 50%. Outcome varies among patient subsets and the elderly often have a poor a priori prognosis. We sought to investigate outcome among elderly AMICS patients referred to evaluation and treatment at a tertiary university hospital. METHODS: Current analysis was based on the RETROSHOCK registry comprising consecutive AMICS patients admitted to tertiary care. Patients in the registry were individually identified and validated. RESULTS: Of 1,716 admitted patients, 496 (28.9%) patients were ≥75 years old. Older patients were less likely to be admitted directly to a tertiary centre (59.4% vs. 69.9%, P = 0.003), receive mechanical support devices (i.e., Impella® (8.9% vs. 15.0%, P = 0.003), and undergo revascularization attempt (76.8% vs. 90.2%, P < 0.001). Thirty-day survivors ≥75 years were characterized by having higher left ventricular ejection fraction (30.2% ±â€Š12.5% vs. 26.5% ±â€Š11.8%, P = 0.004) and lower arterial lactate (3.2[2.2-5.2] mmol/L vs. 5.5[3.3-8.2] mmol/L, P < 0.001) at admission. In a multivariable analysis of patients ≥75 years, higher age (HR 1.09, 95% CI 1.05-1.14, P < 0.001), higher heart rate (HR 1.01, 95% CI 1.001-1.014, P = 0.03), and higher lactate (HR 1.11, 95% CI 1.07-1.16, P < 0.001) at admission were associated with an increased risk of 30-day mortality. CONCLUSION: Among patients ≥75 years with AMICS referred for tertiary specialized treatment, 30-day mortality was 73.4%. Survivors were characterized by lower arterial lactate and heart rate at admission.

Long-Term Changes in Invasive Physiological Pressure Indices of Stenosis Severity Following Transcatheter Aortic Valve Implantation.

BACKGROUND: Patients with severe aortic stenosis frequently have coexisting coronary artery disease. Invasive hyperemic and nonhyperemic pressure indices are used to assess coronary artery disease severity but have not been evaluated in the context of severe aortic stenosis. METHODS: We compared lesion reclassification rates of fractional flow reserve (FFR) and resting full-cycle ratio (RFR) measured before and 6 months after transcatheter aortic valve implantation using the conventional clinical cutoffs of ≤0.80 for FFR and ≤0.89 for RFR. This was a substudy of the ongoing NOTION-3 trial (Third Nordic Aortic Valve Intervention). Two-dimensional quantitative coronary analysis was used to assess changes in angiographic lesion severity. RESULTS: Forty patients were included contributing 50 lesions in which FFR was measured. In 32 patients (36 lesions), RFR was also measured. There was no significant change in diameter stenosis from baseline to follow-up, 49.8% (42.9%-57.1%) versus 52.3% (43.2%-57.8%), P=0.50. RFR improved significantly from 0.88 (0.83%-0.93) at baseline to 0.92 (0.83-0.95) at follow-up, P=0.003, whereas FFR remained unchanged, 0.84 (0.81-0.89) versus 0.86 (0.78-0.90), P=0.72. At baseline, 11 out of 50 (22%) lesions were FFR-positive, whereas 15 out of 50 (30%) were positive at follow-up, P=0.219. Corresponding numbers for RFR were 23 out of 36 (64%) at baseline and 12 out of 36 (33%) at follow-up, P=0.003. CONCLUSIONS: In patients with severe aortic stenosis, physiological assessment of coronary lesions with FFR before transcatheter aortic valve implantation leads to lower reclassification rate at 6-month follow-up, compared with RFR.

The benefit of complete revascularization after primary PCI for STEMI is attenuated by increasing age: Results from the DANAMI-3-PRIMULTI randomized study.

OBJECTIVES: To ascertain the effect of age on outcomes after culprit-only and complete revascularization after Primary PCI (PPCI) for ST-elevation myocardial infarction (STEMI). BACKGROUND: The numbers of older patients being treated with PPCI are increasing. The optimal management of nonculprit stenoses in such patients is unclear. METHODS: We conducted an analysis of patients aged ≥75 years randomized in the DANAMI-3-PRIMULTI study to either culprit-only or complete FFR-guided revascularization. The primary endpoint was a composite of all-cause mortality, nonfatal reinfarction, and ischaemia-driven revascularization of lesions in noninfarct-related arteries after a median of 27 months of follow-up. RESULTS: One hundred and ten of six hundred and twenty seven patients in the DANAMI-3-PRIMULTI trial were aged ≥75 years. These patients were more likely female (p < .001), hypertensive (p < .001), had lower hemoglobin levels (p < .001), and higher serum creatinine levels (p < .001) than the younger patients in the trial. Other than less use of drug-eluting stents (96.6 versus 88.0%: p = .02), there were no significant differences in procedural technique and success between patients aged <75 years and those ≥75 years of age. There was no significant difference in the incidence of the primary endpoint in patients ≥75 years randomized to culprit-only or FFR-guided complete revascularization (HR 1.49 [95% CI 0.57-4.65]; log-rank p = .19; p for interaction versus patients <75 years <.001). There was a significant interaction between age as a continuous variable, treatment assignment, and the primary outcome (p < .001); beyond the age of about 75 years, there may be no prognostic advantage to complete revascularization. CONCLUSIONS: In patients ≥75 years, after treatment of the culprit lesion in STEMI, there is no significant prognostic benefit to prophylactic complete revascularization of nonculprit stenoses. Pending further study, data would support a symptom-guided approach to further invasive treatment.

Vascular Positron Emission Tomography and Restenosis in Symptomatic Peripheral Arterial Disease: A Prospective Clinical Study.

OBJECTIVES: This study determined whether in vivo positron emission tomography (PET) of arterial inflammation (18F-fluorodeoxyglucose [18F-FDG]) or microcalcification (18F-sodium fluoride [18F-NaF]) could predict restenosis following PTA. BACKGROUND: Restenosis following lower limb percutaneous transluminal angioplasty (PTA) is common, unpredictable, and challenging to treat. Currently, it is impossible to predict which patient will suffer from restenosis following angioplasty. METHODS: In this prospective observational cohort study, 50 patients with symptomatic peripheral arterial disease underwent 18F-FDG and 18F-NaF PET/computed tomography (CT) imaging of the superficial femoral artery before and 6 weeks after angioplasty. The primary outcome was arterial restenosis at 12 months. RESULTS: Forty subjects completed the study protocol with 14 patients (35%) reaching the primary outcome of restenosis. The baseline activities of femoral arterial inflammation (18F-FDG tissue-to-background ratio [TBR] 2.43 [interquartile range (IQR): 2.29 to 2.61] vs. 1.63 [IQR: 1.52 to 1.78]; p < 0.001) and microcalcification (18F-NaF TBR 2.61 [IQR: 2.50 to 2.77] vs. 1.69 [IQR: 1.54 to 1.77]; p < 0.001) were higher in patients who developed restenosis. The predictive value of both 18F-FDG (cut-off TBRmax value of 1.98) and 18F-NaF (cut-off TBRmax value of 2.11) uptake demonstrated excellent discrimination in predicting 1-year restenosis (Kaplan Meier estimator, log-rank p < 0.001). CONCLUSIONS: Baseline and persistent femoral arterial inflammation and micro-calcification are associated with restenosis following lower limb PTA. For the first time, we describe a method of identifying complex metabolically active plaques and patients at risk of restenosis that has the potential to select patients for intervention and to serve as a biomarker to test novel interventions to prevent restenosis.

Jeopardized Myocardium and Survival in Patients Presenting to the Catheterization Laboratory With ST-Elevation Myocardial Infarction and Shock.

OBJECTIVE: We aimed to relate the amount of jeopardized myocardium to mortality in shocked patients presenting to the catheterization laboratory with ST-elevation myocardial infarction (STEMI) and cardiogenic shock. BACKGROUND: In contrast with historical data and previous professional guidance, contemporary randomized data suggest that multi-vessel revascularization in such patients does not improve survival; mechanistic insight is incomplete. METHODS: Clinical databases identified cases of STEMI and shock triaged for primary percutaneous coronary intervention (PPCI) in Eastern Denmark from June 2011 to December 2014 (n = 128). British Cardiovascular Intervention Society (BCIS)-1 jeopardy scores were calculated from angiography. The study endpoint was 30-day mortality. RESULTS: Median lactate values were 6.0 [2.9-10.7] mmol/L. 30-day mortality was 53.9%. 68% of patients had multi-vessel coronary disease. Median pre-PCI BCIS-1 myocardial jeopardy scores were 8 [6-10]. After multiple logistic regression increasing age (p = 0.008; odds ratio [OR] 1.06), lactate values (p = 0.017; OR 1.02), mechanical ventilation (p = 0.011; OR 1.25) and a systolic blood pressure ≤ 90 mmHg at end-case (p = 0.005; OR 1.26) were predictive of 30-day mortality. Post-PPCI culprit vessel TIMI 3 flow was associated with reduced mortality (p < 0.001; OR 0.66). There was no association between pre-PCI jeopardy scores and the primary endpoint. CONCLUSIONS: In patients with STEMI and shock, myocardial jeopardy scores do not relate to patient outcomes. Jeopardy scores may be applied to existing datasets in order to understand why multi-vessel revascularization does not lead to the anticipated clinical benefits in cardiogenic shock.

Cardiogenic Shock After Arterial Y-Graft Coronary Bypass Surgery Secondary to Critical Stenoses of the Left Subclavian and Left Main Coronary Arteries.

We present a case of a 62-year-old man who was in cardiogenic shock. He had a history of coronary artery bypass grafting 4 years previously, with left internal mammary radial artery Y-grafting to a left dominant coronary circulation. Critical stenoses of the left main coronary and left subclavian arteries were seen at angiography. An occluded abdominal aorta precluded the use of mechanical circulatory support. The patient underwent high-risk stenting of the left subclavian artery with a successful outcome. The case highlights the unresolved issue of screening for subclavian stenoses in patients being considered for revascularization with arterial Y-grafting.

Lower limb arterial calcification (LLAC) scores in patients with symptomatic peripheral arterial disease are associated with increased cardiac mortality and morbidity.

AIMS: The association of coronary arterial calcification with cardiovascular morbidity and mortality is well-recognized. Lower limb arterial calcification (LLAC) is common in PAD but its impact on subsequent health is poorly described. We aimed to determine the association between a LLAC score and subsequent cardiovascular events in patients with symptomatic peripheral arterial disease (PAD). METHODS: LLAC scoring, and the established Bollinger score, were derived from a database of unenhanced CT scans, from patients presenting with symptomatic PAD. We determined the association between these scores outcomes. The primary outcome was combined cardiac mortality and morbidity (CM/M) with a secondary outcome of all-cause mortality. RESULTS: 220 patients (66% male; median age 69 years) were included with follow-up for a median 46 [IQR 31-64] months. Median total LLAC scores were higher in those patients suffering a primary outcome (6831 vs. 1652; p = 0.012). Diabetes mellitus (p = 0.039), ischaemic heart disease (p = 0.028), chronic kidney disease (p = 0.026) and all-cause mortality (p = 0.012) were more common in patients in the highest quartile of LLAC scores. The area under the curve of the receiver operator curve for the LLAC score was greater (0.929: 95% CI [0.884-0.974]) than for the Bollinger score (0.824: 95% CI [0.758-0.890]) for the primary outcome. A LLAC score ≥ 4400 had the best diagnostic accuracy to determine the outcome measure. CONCLUSION: This is the largest study to investigate links between lower limb arterial calcification and cardiovascular events in symptomatic PAD. We describe a straightforward, reproducible, CT-derived measure of calcification-the LLAC score.

Detection of Atherosclerotic Inflammation by 68Ga-DOTATATE PET Compared to [18F]FDG PET Imaging.

BACKGROUND: Inflammation drives atherosclerotic plaque rupture. Although inflammation can be measured using fluorine-18-labeled fluorodeoxyglucose positron emission tomography ([18F]FDG PET), [18F]FDG lacks cell specificity, and coronary imaging is unreliable because of myocardial spillover. OBJECTIVES: This study tested the efficacy of gallium-68-labeled DOTATATE (68Ga-DOTATATE), a somatostatin receptor subtype-2 (SST2)-binding PET tracer, for imaging atherosclerotic inflammation. METHODS: We confirmed 68Ga-DOTATATE binding in macrophages and excised carotid plaques. 68Ga-DOTATATE PET imaging was compared to [18F]FDG PET imaging in 42 patients with atherosclerosis. RESULTS: Target SSTR2 gene expression occurred exclusively in "proinflammatory" M1 macrophages, specific 68Ga-DOTATATE ligand binding to SST2 receptors occurred in CD68-positive macrophage-rich carotid plaque regions, and carotid SSTR2 mRNA was highly correlated with in vivo 68Ga-DOTATATE PET signals (r = 0.89; 95% confidence interval [CI]: 0.28 to 0.99; p = 0.02). 68Ga-DOTATATE mean of maximum tissue-to-blood ratios (mTBRmax) correctly identified culprit versus nonculprit arteries in patients with acute coronary syndrome (median difference: 0.69; interquartile range [IQR]: 0.22 to 1.15; p = 0.008) and transient ischemic attack/stroke (median difference: 0.13; IQR: 0.07 to 0.32; p = 0.003). 68Ga-DOTATATE mTBRmax predicted high-risk coronary computed tomography features (receiver operating characteristics area under the curve [ROC AUC]: 0.86; 95% CI: 0.80 to 0.92; p < 0.0001), and correlated with Framingham risk score (r = 0.53; 95% CI: 0.32 to 0.69; p <0.0001) and [18F]FDG uptake (r = 0.73; 95% CI: 0.64 to 0.81; p < 0.0001). [18F]FDG mTBRmax differentiated culprit from nonculprit carotid lesions (median difference: 0.12; IQR: 0.0 to 0.23; p = 0.008) and high-risk from lower-risk coronary arteries (ROC AUC: 0.76; 95% CI: 0.62 to 0.91; p = 0.002); however, myocardial [18F]FDG spillover rendered coronary [18F]FDG scans uninterpretable in 27 patients (64%). Coronary 68Ga-DOTATATE PET scans were readable in all patients. CONCLUSIONS: We validated 68Ga-DOTATATE PET as a novel marker of atherosclerotic inflammation and confirmed that 68Ga-DOTATATE offers superior coronary imaging, excellent macrophage specificity, and better power to discriminate high-risk versus low-risk coronary lesions than [18F]FDG. (Vascular Inflammation Imaging Using Somatostatin Receptor Positron Emission Tomography [VISION]; NCT02021188).

Invasive angiography and revascularization in patients with stable angina following prior coronary artery bypass grafting: Results from the East Denmark heart registry.

BACKGROUND: There are limited data to guide the optimum approach to patients presenting with angina after coronary artery bypass grafting (CABG). Although often referred for invasive angiography, the effectiveness of this is unknown; angina may also result from diffuse distal or micro-vascular coronary disease and it is not known how often targets for intervention are identified. METHODS: Retrospective review of 50,460 patients undergoing angiography in East Denmark between January 2010 and December 2014. Clinical and procedural data were prospectively stored in a regional electronic database. Follow-up data were available for all patients, by means of records linked to each Danish social security number. RESULTS: In patients with prior CABG and stable angina (n = 2,309), diagnostic angiography led to revascularization in 574 (24.9%) cases. Chronic kidney disease (HR 1.93 [1.08-3.44], P = 0.027), significant angina (HR 1.49 [1.18-1.88], P = 0.006 for angina class ≥ II, and HR 2.04 [1.61-2.58], P < 0.001 for angina class ≥ III) and a positive pre-procedural stress test (HR 2.56 [1.42-4.60], P < 0.001) were independent predictors of revascularization. Stress testing was, however, used less frequently than in patients without prior CABG (17.2% vs. 24.2%, P < 0.001). The positive predictive values for subsequent revascularization were 47.8%, 51.4%, and 66.9% for exercise ECG, stress echocardiography, and myocardial perfusion scintigraphy (MPS), respectively. CONCLUSIONS: Invasive angiography leads to revascularization in a quarter of patients with angina and prior CABG; the threshold for referral may be too low. Non-invasive stress testing predicts the need for revascularization but appears underused and MPS, in particular, may better identify patients likely to require revascularization. © 2016 Wiley Periodicals, Inc.

Does Vascular Calcification Accelerate Inflammation?: A Substudy of the dal-PLAQUE Trial.

BACKGROUND: Atherosclerosis is an inflammatory condition with calcification apparent late in the disease process. The extent and progression of coronary calcification predict cardiovascular events. Relatively little is known about noncoronary vascular calcification. OBJECTIVES: This study investigated noncoronary vascular calcification and its influence on changes in vascular inflammation. METHODS: A total of 130 participants in the dal-PLAQUE (Safety and efficacy of dalcetrapib on atherosclerotic disease using novel non-invasive multimodality imaging) study underwent fluorodeoxyglucose positron emission tomography/computed tomography at entry and at 6 months. Calcification of the ascending aorta, arch, carotid, and coronary arteries was quantified. Cardiovascular risk factors were related to arterial calcification. The influences of baseline calcification and drug therapy (dalcetrapib vs. placebo) on progression of calcification were determined. Finally, baseline calcification was related to changes in vascular inflammation. RESULTS: Age >65 years old was consistently associated with higher baseline calcium scores. Arch calcification trended to progress more in those with calcification at baseline (p = 0.055). There were no significant differences between progression of vascular calcification with dalcetrapib compared to that with placebo. Average carotid target-to-background ratio indexes declined over 6 months if carotid calcium was absent (single hottest slice [p = 0.037], mean of maximum target-to-background ratio [p = 0.010], and mean most diseased segment [p < 0.001]), but did not significantly change if calcification was present at baseline. CONCLUSIONS: Across multiple arterial regions, higher age is consistently associated with higher calcium scores. The presence of vascular calcification at baseline is associated with progressive calcification; in the carotid arteries, calcification appears to influence vascular inflammation. Dalcetrapib therapy did not affect vascular calcification.

Identifying active vascular microcalcification by (18)F-sodium fluoride positron emission tomography.

Vascular calcification is a complex biological process that is a hallmark of atherosclerosis. While macrocalcification confers plaque stability, microcalcification is a key feature of high-risk atheroma and is associated with increased morbidity and mortality. Positron emission tomography and X-ray computed tomography (PET/CT) imaging of atherosclerosis using (18)F-sodium fluoride ((18)F-NaF) has the potential to identify pathologically high-risk nascent microcalcification. However, the precise molecular mechanism of (18)F-NaF vascular uptake is still unknown. Here we use electron microscopy, autoradiography, histology and preclinical and clinical PET/CT to analyse (18)F-NaF binding. We show that (18)F-NaF adsorbs to calcified deposits within plaque with high affinity and is selective and specific. (18)F-NaF PET/CT imaging can distinguish between areas of macro- and microcalcification. This is the only currently available clinical imaging platform that can non-invasively detect microcalcification in active unstable atherosclerosis. The use of (18)F-NaF may foster new approaches to developing treatments for vascular calcification.

PET imaging of atherosclerosis.

Atherosclerosis is a chronic, progressive, multifocal disease of the arterial wall, which is mainly fuelled by local and systemic inflammation, often resulting in acute ischemic events following plaque rupture and vessel occlusion. When assessing the cardiovascular risk of an individual patient, we must consider both global measures of disease activity and local features of plaque vulnerability, in addition to anatomical distribution and degree of established atherosclerosis. These parameters cannot be measured with conventional anatomical imaging techniques alone, which are designed primarily to identify the presence of organic intraluminal obstruction in symptomatic patients. However, molecular imaging with PET, using specifically targeted radiolabeled probes to track active in vivo atherosclerotic mechanisms noninvasively, may potentially provide a method that is better suited for this purpose. Vascular PET imaging can help us to further understand aspects of plaque biology, and current evidence supports a future role as an emerging clinical tool for the quantification of cardiovascular risk in order to guide and monitor responses to antiatherosclerosis treatments and to distinguish high-risk plaques.

PET imaging of inflammation in atherosclerosis.

PET imaging of atherosclerosis can quantify several in vivo pathological processes occurring within the arterial system. (18)F-fluorodeoxyglucose (FDG) is the most-commonly used PET tracer, with well-established roles in atherosclerosis imaging. In this context, the (18)F-FDG signal largely reflects tracer uptake by plaque macrophages and, therefore, inflammation with smaller contributions from other resident cell types. As a marker of plaque vulnerability, the (18)F-FDG PET signal can be used to help to identify patients at the highest risk of clinical events. (18)F-FDG PET has also been used successfully as a surrogate end point in clinical trials of antiatherosclerotic therapies. Nonetheless, imaging atherosclerosis with (18)F-FDG has several limitations. Most importantly, coronary artery imaging is problematic because (18)F-FDG accumulates in all cells that metabolize glucose, and background myocardial uptake is generally greater than any signal originating from a plaque. To help to overcome these limitations, several novel PET tracers, which might be more-specifically targeted than (18)F-FDG, have been tested in atherosclerosis imaging. These tracers are designed to track inflammation, hypoxia, neoangiogenesis, or active calcification, which are all precursors to plaque rupture and its clinical sequelae.

Anti-tumor necrosis factor-α therapy reduces aortic inflammation and stiffness in patients with rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is a systemic inflammatory condition associated with increased cardiovascular risk. This is not fully explained by traditional risk factors, but direct vascular inflammation and aortic stiffening may play a role. We hypothesized that patients with RA exhibit aortic inflammation, which can be reversed with anti-tumor necrosis factor-α therapy and correlates with aortic stiffness reduction. METHODS AND RESULTS: Aortic inflammation was quantified in 17 patients with RA, before and after 8 weeks of anti-tumor necrosis factor-α therapy by using (18)F-fluorodeoxyglucose positron emission tomography with computed tomography coregistration. Concomitantly, 34 patients with stable cardiovascular disease were imaged as positive controls at baseline. Aortic fluorodeoxyglucose target-to-background ratios (TBRs) and aortic pulse wave velocity were assessed. RA patients had higher baseline aortic TBRs in comparison with patients who have cardiovascular disease (2.02±0.22 versus 1.74±0.22, P=0.0001). Following therapy, aortic TBR fell to 1.90±0.29, P=0.03, and the proportion of inflamed aortic slices (defined as TBR >2.0) decreased from 50±33% to 33±27%, P=0.03. Also, TBR in the most diseased segment of the aorta fell from 2.51±0.33 to 2.05±0.29, P<0.0001. Treatment also reduced aortic pulse wave velocity significantly (from 9.09±1.77 to 8.63±1.42 m/s, P=0.04), which correlated with the reduction of aortic TBR (R=0.60, P=0.01). CONCLUSIONS: This study demonstrates that RA patients have increased aortic (18)F-fluorodeoxyglucose uptake in comparison with patients who have stable cardiovascular disease. Anti-tumor necrosis factor-α therapy reduces aortic inflammation in patients with RA, and this effect correlates with the decrease in aortic stiffness. These results suggest that RA patients exhibit a subclinical vasculitis, which provides a mechanism for the increased cardiovascular disease risk seen in RA.