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.

The value of coronary computed tomography and very early invasive coronary angiography compared to standard intervention in older patients after non-ST segment elevation acute coronary syndromes

Background

The optimal management of patients with non-ST elevation acute coronary syndromes (NSTEACS) remains a challenge. The merits of both computed tomography angiography (CTA) as a rule-out test for significant coronary artery disease and early invasive coronary angiography (ICA) are debated. Furthermore, there are limited data in older NSTEACS patients, who likely have more coronary artery calcification and are at higher risk of ACS-related complications.

Methods

This is a post hoc analysis of patients ≥75 years included in the Very Early Versus Standard Care Invasive Examination and Treatment of Patients with Non-ST-Segment Elevation Acute Coronary Syndrome Trial (VERDICT). The diagnostic accuracy of CTA was investigated in patients without previous coronary artery bypass grafting, renal dysfunction, or atrial fibrillation; the presence of a coronary artery stenosis ≥50% determined by ICA was used as reference. Patients were randomised to very early ICA within 12 hours of diagnosis or standard care (ICA within 48–72 hours of diagnosis) and followed for up to five years. The primary endpoint was the composite of all-cause mortality, nonfatal recurrent MI, hospital admission for refractory myocardial ischaemia or hospital admission for heart failure.

Results

From November 2010 to June 2016, 2147 patients were included in the VERDICT trial. Of these, 452 (21%) patients were ≥75 years of age. Most older patients had a GRACE score &gt;140 (n=388, 88.8%). At the time of admission, older patients had lower levels of haemoglobin, estimated glomerular filtration rate, and left ventricular ejection fraction, and more often displayed elevated troponins and electrocardiogram changes indicating new ischaemia, than those &lt;75 years.

Of patients ≥75 years of age, 161 (35.6%) underwent CTA before ICA. Older patients had significantly higher calcium scores than younger patients (1187±1445 vs. 499±858 Agatston units, p&lt;0.001). 19% of CTAs excluded significant coronary artery disease. The negative predictive value of the CTAs was 94 (95% CI 79–99)% and the sensitivity was 98 (95% CI 94–100)%, figure 1.

The primary endpoint was observed more frequently in patients ≥75 years as compared to younger patients (n=222, 49% vs. n=390, 23%, p&lt;0.001), even after adjustment for allocated treatment (adjusted HR 2.65, 95% CI 2.25–3.13, p&lt;0.001). Among older patients randomised to very early ICA, there were no differences in the cumulated number of primary endpoints compared to older patients randomised to standard ICA (log-rank p=0.36), figure 2.

Conclusion

Among patients ≥75 years old with NSTEACS, CTA showed a high diagnostic accuracy. A very early ICA within 12 hours of diagnosis did not improve long-term composite outcome in these older patients with NSTEACS.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Rigshospitalets Research Foundation

Misclassification rate of the angiographically identified culprit lesion in NSTEMI

Background

Correct identification of the culprit lesion in NSTEMI is essential, in particular for patients in whom a culprit-only strategy is attractive (e.g., elderly and frail patients). However, when identifying the culprit lesion in NSTEMI, angiography can be ambiguous and correct culprit identification can therefore be challenging when based on angiography, ECG- and echocardiographic changes alone (standard-of-care). In fact, this challenge remains unresolved and is a continuous limitation in guidelines and in the few clinical trials investigating the revascularization strategy in NSTEMI.

Purpose

We aimed to investigate the agreement between angiography and cardiac magnetic resonance (CMR) and optical coherence tomography (OCT) in identifying the culprit lesion in non-ST segment elevation myocardial infarction (NSTEMI).

Methods

In two centres we prospectively enrolled 104 patients. CMR was performed prior to angiography. Operators, blinded to CMR, identified a culprit lesion based on angiography and standard-of-care. OCT was subsequently performed on operator-suspected culprit lesions and stenoses ≥50% diameter. CMR and OCT were reviewed blinded to angiographic culprit identification. Myocardial oedema on CMR was considered the reference standard for a culprit. In the absence of oedema, OCT was used. In case of multiple suspected OCT-lesions, hierarchical criteria for culprit identification were used: acute thrombus &gt; plaque rupture with a cavity &gt; organising thrombus &gt; dissection &gt; calcific nodule.

Results

The majority of included patients were male (75%) at a mean 63 years of age. Obstructive disease was observed in 85 (82%) patients, of which 53 (51%) had multivessel disease. On a patient-level, angiography identified a culprit lesion in 90 (87%) patients, of which CMR/OCT only identified a culprit in 74 (82%) patients. This constituted a moderate overall positive predictive value of angiography, which was found inferior to CMR/OCT in identifying the culprit lesion. On a lesion-level, CMR/OCT identified a different culprit lesion than angiography in 12 (16%) patients. Of these, only one patient did not receive revascularization of the true culprit lesion. Moreover, in the 14 patients without an angiographic culprit, CMR/OCT identified a culprit in 7 (50%) patients. Thus, angiography including standard-of-care falsely identified the culprit lesion in overall 35 (34%) patients: 7 false negatives, 16 false positive at patient-level, and 12 misclassified angiographic culprits on lesion-level (Figure 1). Specifically, OCT identified 13% misclassified culprit lesions in proximal segments, and provided an added diagnostic value.

Conclusions

Angiography misclassified the culprit lesion in one in three patients with NSTEMI with respect to both presence and location. OCT complemented angiography in ambiguous cases which underscores the value of OCT in aiding treatment and diagnosis in NSTEMI.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Research Grant at Rigshospitalet, Copenhagen University Hospital, DenmarkNovo Nordisk Foundation, Denmark

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.

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% ± 12.5% vs. 26.5% ± 11.8%, 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 TBR_max value of 1.98) and ¹⁸F-NaF (cut-off TBR_max 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.

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 (mTBR_max) 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 mTBR_max 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 mTBR_max 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.

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

ABSTRACT 

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.

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.

Non-invasive imaging of atherosclerosis

Atherosclerosis is an inflammatory disease that causes most myocardial infarctions, strokes, and acute coronary syndromes. Despite the identification of multiple risk factors and widespread use of drug therapies, it still remains a global health concern with associated costs. It is well known that the risks of atherosclerotic plaque rupture are not well correlated with stenosis severity. Lumenography has a central place for defining the site and severity of vascular stenosis as a prelude to intervention for relief of symptoms due to blood flow limitation. Atherosclerosis develops within the arterial wall; this is not imaged by lumenography and hence it provides no information regarding underlying processes that may lead to plaque rupture. For this, we must rely on other imaging modalities such as ultrasound, computed tomography, magnetic resonance imaging, and nuclear imaging methods. These are capable of reporting on the underlying pathology, in particular the presence of inflammation, calcification, neovascularization, and intraplaque haemorrhage. Additionally, non-invasive imaging can now be used to track the effect of anti-atherosclerosis therapy. Each modality alone has positives and negatives and this review will highlight these, as well as speculating on future developments in this area.