Coronary microvascular dysfunction (CMD) is a prevalent and prognostically important finding in patients with symptoms suggestive of coronary artery disease. The relative extent to which CMD affects ...both sexes is largely unknown.
We investigated 405 men and 813 women who were referred for evaluation of suspected coronary artery disease with no previous history of coronary artery disease and no visual evidence of coronary artery disease on rest/stress positron emission tomography myocardial perfusion imaging. Coronary flow reserve was quantified, and coronary flow reserve <2.0 was used to define the presence of CMD. Major adverse cardiac events, including cardiac death, nonfatal myocardial infarction, late revascularization, and hospitalization for heart failure, were assessed in a blinded fashion over a median follow-up of 1.3 years (interquartile range, 0.5-2.3 years). CMD was highly prevalent both in men and women (51% and 54%, respectively; Fisher exact test =0.39; equivalence P=0.0002). Regardless of sex, coronary flow reserve was a powerful incremental predictor of major adverse cardiac events (hazard ratio, 0.80 95% confidence interval, 0.75-086 per 10% increase in coronary flow reserve; P<0.0001) and resulted in favorable net reclassification improvement (0.280 95% confidence interval, 0.049-0.512), after adjustment for clinical risk and ventricular function. In a subgroup (n=404; 307 women/97 men) without evidence of coronary artery calcification on gated computed tomography imaging, CMD was common in both sexes, despite normal stress perfusion imaging and no coronary artery calcification (44% of men versus 48% of women; Fisher exact test P=0.56; equivalence P=0.041).
CMD is highly prevalent among at-risk individuals and is associated with adverse outcomes regardless of sex. The high prevalence of CMD in both sexes suggests that it may be a useful target for future therapeutic interventions.
Objectives This study sought to relate imaging findings on positron emission tomography (PET) to adverse cardiac events in patients referred for evaluation of known or suspected cardiac sarcoidosis. ...Background Although cardiac PET is commonly used to evaluate patients with suspected cardiac sarcoidosis, the relationship between PET findings and clinical outcomes has not been reported. Methods We studied 118 consecutive patients with no history of coronary artery disease, who were referred for PET, using 18 Ffluorodeoxyglucose (FDG) to assess for inflammation and rubidium-82 to evaluate for perfusion defects (PD), following a high-fat/low-carbohydrate diet to suppress normal myocardial glucose uptake. Blind readings of PET data categorized cardiac findings as normal, positive PD or FDG, positive PD and FDG. Images were also used to identify whether findings of extra-cardiac sarcoidosis were present. Adverse events (AE)—death or sustained ventricular tachycardia (VT)—were ascertained by electronic medical records, defibrillator interrogation, patient questionnaires, and telephone interviews. Results Among the 118 patients (age 52 ± 11 years; 57% males; mean ejection fraction: 47 ± 16%), 47 (40%) had normal and 71 (60%) had abnormal cardiac PET findings. Over a median follow-up of 1.5 years, there were 31 (26%) adverse events (27 VT and 8 deaths). Cardiac PET findings were predictive of AE, and the presence of both a PD and abnormal FDG (29% of patients) was associated with hazard ratio of 3.9 (p < 0.01) and remained significant after adjusting for left ventricular ejection fraction (LVEF) and clinical criteria. Extra-cardiac FDG uptake (26% of patients) was not associated with AE. Conclusions The presence of focal PD and FDG uptake on cardiac PET identifies patients at higher risk of death or VT. These findings offer prognostic value beyond Japanese Ministry of Health and Welfare clinical criteria, the presence of extra-cardiac sarcoidosis and LVEF.
Myocardial perfusion imaging has limited sensitivity for the detection of high-risk coronary artery disease (CAD). We tested the hypothesis that a normal coronary flow reserve (CFR) would be helpful ...for excluding the presence of high-risk CAD on angiography.
We studied 290 consecutive patients undergoing (82)Rb PET within 180 d of invasive coronary angiography. High-risk CAD on angiography was defined as 2-vessel disease (≥ 70% stenosis), including the proximal left anterior descending artery; 3-vessel disease; or left main CAD (≥ 50% stenosis). Patients with prior Q wave myocardial infarction, elevated troponin levels between studies, prior coronary artery bypass grafting, a left ventricular ejection fraction of less than 40%, or severe valvular heart disease were excluded.
Fifty-five patients (19%) had high-risk CAD on angiography. As expected, the trade-off between the sensitivity and the specificity of the CFR for identifying high-risk CAD varied substantially depending on the cutoff selected. In multivariable analysis, a binary CFR of less than or equal to 1.93 provided incremental diagnostic information for the identification of high-risk CAD beyond the model with the Duke clinical risk score (>25%), percentage of left ventricular ischemia (>10%), transient ischemic dilation index (>1.07), and change in the left ventricular ejection fraction during stress (<2) (P = 0.0009). In patients with normal or slightly to moderately abnormal results on perfusion scans (<10% of left ventricular mass) during stress (n = 136), a preserved CFR (>1.93) excluded high-risk CAD with a high sensitivity (86%) and a high negative predictive value (97%).
A normal CFR has a high negative predictive value for excluding high-risk CAD on angiography. Although an abnormal CFR increases the probability of significant obstructive CAD, it cannot reliably distinguish significant epicardial stenosis from nonobstructive, diffuse atherosclerosis or microvascular dysfunction.
Minimally elevated serum cardiac troponin reflects myocardial injury and is associated with increased mortality, even absent coronary artery disease (CAD). We sought to investigate the relationship ...between low-level troponin elevation and impaired coronary flow reserve (CFR), an integrated measure of coronary vasomotor function, and to assess their contributions to adverse outcomes in patients without overt CAD.
Consecutive patients (n=761) undergoing evaluation for suspected CAD with troponin before stress myocardial perfusion positron emission tomography were followed up (median, 2.8 years) for major adverse cardiovascular events, including cardiovascular death, nonfatal myocardial infarction, or late revascularization. Patients with flow-limiting CAD, left ventricular ejection fraction <40%, or revascularization within 60 days of imaging were excluded. CFR was quantified from stress/rest myocardial blood flow with the use of positron emission tomography. Compared with patients with negative troponin, those with at least 1 positive troponin (n=97) had higher pretest clinical scores, more renal dysfunction, and lower left ventricular ejection fraction and CFR. In adjusted analysis, impaired CFR remained independently associated with positive troponin (odds ratio, 2.18; 95% confidence interval, 1.37-3.47; P=0.001), and both impaired CFR and positive troponin were independently associated with major adverse cardiovascular events (hazard ratio, 2.25; 95% confidence interval, 1.31-3.86; P=0.003; and hazard ratio, 2.42; 95% confidence interval, 1.34-4.40; P=0.004, respectively). Impaired CFR and positive troponin identified patients at highest risk of major adverse cardiovascular events (log-rank P<0.0001), with a significant interaction (P<0.007) seen between CFR and troponin.
In patients without overt CAD, impaired CFR was independently associated with minimally elevated troponin and major adverse cardiovascular events. Impaired CFR, here reflecting microvascular dysfunction, modified the effect of a positive troponin on adverse outcomes.
Despite significant progress in primary prevention, the rate of myocardial infarction has not decreased in young adults. We sought to compare the risk factor profiles and outcomes between individuals ...who experienced a first myocardial infarction at a very young (≤40 years) and a young (age 41-50 years) age.
We evaluated all patients ≤50 years of age admitted with a Type 1 myocardial infarction to 2 large academic hospitals from 2000 to 2016. Risk factors were determined by review of electronic medical records. The primary outcomes of interest were all-cause and cardiovascular mortality.
Among 2097 consecutive young patients with myocardial infarction, 431 (20.5%) were ≤40 years of age. When compared with their older counterparts, very young patients had similar risk profiles, with the exception of greater substance abuse (17.9% vs 9.3%, P < .001) and less hypertension (37.9% vs 50.9%, P < .001). Spontaneous coronary artery dissection was more prevalent in very young patients (3.1% vs 1.1%, P = .003). Over a median follow-up of 11.2 years, very young myocardial infarction patients had a similar risk of all-cause and cardiovascular mortality.
Despite being, on average, 10 years younger and having a lower prevalence of hypertension, very young myocardial infarction patients had similar 1-year and long-term outcomes when compared with those aged 41 to 50 years at the time of their index infarction. Our findings suggest the need for aggressive secondary prevention measures in very young patients who experience a myocardial infarction.
The contribution of plaque extent to predict cardiovascular events among patients with nonobstructive and obstructive coronary artery disease (CAD) is not well defined. Our objective was to evaluate ...the prognostic value of plaque extent detected by coronary computed tomography angiography.
All consecutive patients without prior CAD referred for coronary computed tomography angiography to evaluate for CAD were included. Examination findings were classified as normal, nonobstructive (<50% stenosis), or obstructive (≥50%). Based on the number of segments with disease, extent of CAD was classified as nonextensive (≤4 segments) or extensive (>4 segments). The cohort included 3242 patients followed for the primary outcome of cardiovascular death or myocardial infarction for a median of 3.6 (2.1-5.0) years. In a multivariable analysis, the presence of extensive nonobstructive CAD (hazard ratio, 3.1; 95% confidence interval, 1.5-6.4), nonextensive obstructive (hazard ratio, 3.0; 95% confidence interval, 1.3-6.9), and extensive obstructive CAD (hazard ratio, 3.9; 95% confidence interval, 2.2-7.2) were associated with an increased rate of events, whereas nonextensive, nonobstructive CAD was not. The addition of plaque extent to a model that included clinical probability as well as the presence and severity of CAD improved risk prediction.
Among patients with nonobstructive CAD, those with extensive plaque experienced a higher rate of cardiovascular death or myocardial infarction, comparable with those who have nonextensive disease. Even among patients with obstructive CAD, greater extent of nonobstructive plaque was associated with higher event rate. Our findings suggest that regardless of whether obstructive or nonobstructive disease is present, the extent of plaque detected by coronary computed tomography angiography enhances risk assessment.
Objective
Coronary microvascular dysfunction (CMD) is a predictor of cardiac death in diabetes mellitus (DM) independent of traditional cardiovascular (CV) risk factors. Rheumatoid arthritis (RA) is ...a chronic inflammatory condition, with excess CV risk compared to the general population, in which CMD is hypothesized to play a role; however, there are limited data on CMD in RA and any association with clinical outcomes. The objective of this study was to compare the prevalence of CMD in RA to that in DM and to test the association with all‐cause mortality.
Methods
We performed a retrospective cohort study using data from a registry of all patients undergoing stress myocardial perfusion positron emission tomography as part of routine clinical care from 2006 to 2017. The inclusion criterion was a normal perfusion scan. Patients with RA or DM were classified using previously published approaches. Coronary flow reserve (CFR) was calculated for all patients in the registry and linked with mortality data. CMD was defined as CFR <2.0.
Results
We studied 73 patients with RA and 441 patients with DM. Among patients with a normal perfusion scan, the prevalence of CMD in RA was similar to that in DM (P = 0.2). CMD was associated with increased risk for all‐cause mortality in RA (hazard ratio 2.4 95% confidence interval 1.4–4.2) as well as increased risk for cardiac‐related death at rates similar to those in DM.
Conclusion
These findings suggest an important role for CMD as a potential contributor to excess CV risk and mortality in RA, as previously observed in DM, as well as evidence for a mechanistic link between inflammation and cardiovascular disease.
Abstract
Aims
Hypertension is a well-established heart failure (HF) risk factor, especially in the context of adverse left ventricular (LV) remodelling. We aimed to use myocardial flow reserve (MFR) ...and global longitudinal strain (GLS), markers of subclinical microvascular and myocardial dysfunction, to refine hypertensive HF risk assessment.
Methods and results
Consecutive patients undergoing symptom-prompted stress cardiac positron emission tomography (PET)-computed tomography and transthoracic echocardiogram within 90 days without reduced left ventricular ejection fraction (<40%) or flow-limiting coronary artery disease (summed stress score ≥ 3) were included. Global MFR was quantified by PET, and echocardiograms were retrospectively analysed for cardiac structure and function. Patients were followed over a median 8.75 (Q1–3 4.56–10.04) years for HF hospitalization and a composite of death, HF hospitalization, MI, or stroke. Of 194 patients, 155 had adaptive LV remodelling while 39 had maladaptive remodelling, which was associated with lower MFR and impaired GLS. Across the remodelling spectrum, diastolic parameters, GLS, and N-terminal pro-B-type natriuretic peptide were independently associated with MFR. Maladaptive LV remodelling was associated with increased adjusted incidence of HF hospitalization and death. Importantly, the combination of abnormal MFR and GLS was associated with a higher rate of HF hospitalization compared to normal MFR and GLS adjusted hazard ratio (HR) 3.21, 95% confidence interval (CI) 1.09–9.45, P = 0.034), including in the adaptive remodelling subset (adjusted HR 3.93, 95% CI 1.14–13.56, P = 0.030).
Conclusion
We have demonstrated important associations between coronary microvascular dysfunction and myocardial mechanics that refine disease characterization and HF risk assessment of patients with hypertension based on subclinical target organ injury.
Microvascular rarefaction is found in experimental uremia, but data from patients with chronic kidney disease (CKD) are limited. We therefore quantified absolute myocardial blood flow and coronary ...flow reserve (the ratio of peak to resting flow) from myocardial perfusion positron emission tomography scans at a single institution. Individuals were classified into standard CKD categories based on the estimated glomerular filtration rate. Associations of coronary flow reserve with CKD stage and cardiovascular mortality were analyzed in models adjusted for cardiovascular risk factors. The coronary flow reserve was significantly associated with CKD stage, declining in early CKD, but it did not differ significantly among individuals with stage 4, 5, and dialysis-dependent CKD. Flow reserve with preserved kidney function was 2.01, 2.06 in stage 1 CKD, 1.91 in stage 2, 1.68 in stage 3, 1.54 in stage 4, 1.66 in stage 5, and 1.55 in dialysis-dependent CKD. Coronary flow reserve was significantly associated with cardiovascular mortality in adjusted models (hazard ratio 0.76, 95% confidence interval: 0.63-0.92 per tertile of coronary flow reserve) without evidence of effect modification by CKD. Thus, coronary flow reserve is strongly associated with cardiovascular risk regardless of CKD severity and is low in early stage CKD without further decrement in stage 5 or dialysis-dependent CKD. This suggests that CKD physiology rather than the effects of dialysis is the primary driver of microvascular disease. Our findings highlight the potential contribution of microvascular dysfunction to cardiovascular risk in CKD and the need to define mechanisms linking low coronary flow reserve to mortality.
Type 2 myocardial infarction (MI) and myocardial injury are associated with increased short-term mortality. However, data regarding long-term mortality are lacking.
This study compared long-term ...mortality among young adults with type 1 MI, type 2 MI, or myocardial injury.
Adults age 50 years or younger who presented with troponin >99th percentile or the International Classification of Diseases code for MI over a 17-year period were identified. All cases were adjudicated as type 1 MI, type 2 MI, or myocardial injury based on the Fourth Universal Definition of MI. Cox proportional hazards models were constructed for survival free from all-cause and cardiovascular death.
The cohort consisted of 3,829 patients (median age 44 years; 30% women); 55% had type 1 MI, 32% had type 2 MI, and 13% had myocardial injury. Over a median follow-up of 10.2 years, mortality was highest for myocardial injury (45.6%), followed by type 2 MI (34.2%) and type 1 MI (12%) (p < 0.001). In an adjusted model, type 2 MI was associated with higher all-cause (hazard ratio: 1.8; 95% confidence interval: 1.2 to 2.7; p = 0.004) and cardiovascular mortality (hazard ratio: 2.7; 95% confidence interval: 1.4 to 5.1; p = 0.003) compared with type 1 MI. Those with type 2 MI or myocardial injury were younger and had fewer cardiovascular risk factors but had more noncardiovascular comorbidities. They were significantly less likely to be prescribed cardiovascular medications at discharge.
Young patients who experience a type 2 MI have higher long-term all-cause and cardiovascular mortality than those who experience type 1 MI, with nearly one-half of patients with myocardial injury and more than one-third of patients with type 2 MI dying within 10 years. These findings emphasize the need to provide more aggressive secondary prevention for patients who experience type 2 MI and myocardial injury.
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