Prognostic value of heart rate reserve in patients with suspected coronary artery disease undergoing stress myocardial perfusion imaging

Funding Acknowledgements

Type of funding sources: None.

Background. The prognostic value of stress myocardial perfusion single-photon emission computed tomography (MPS) has been widely demonstrated. Also, chronotropic incompetence, evaluated by heart rate reserve (HRR) is associated with increased risk of adverse events. Yet, the incremental prognostic value of HRR over stress MPS data has not been fully investigated.

Purpose. To assess the incremental prognostic value of HRR over stress MPS finding in patients with suspected coronary artery disease (CAD) undergoing exercise stress MPS.

Methods. The study population consisted of 866 consecutive patients with suspected CAD undergoing exercise stress-MPS at University of Naples Federico II, between May 2002 and January 2014 as part of their diagnostic program. The primary study endpoint was all-cause mortality. All patients were followed for at least 60 months. HRR was calculated as the difference between peak exercise and resting HR, divided by the difference of age-predicted maximal and resting HR and expressed as percent. The summed difference score (SDS) was considered an index of ischemic burden. Patients were considered to have mild ischemia with a SDS of 2 to 6, and moderate-severe ischemia with a SDS ≥6. During follow-up, the occurrence of all-cause of deaths was noted and considered as event. Follow-up was censored at 84 months.

Results. During follow-up, 61 deaths occurred, with a 7% cumulative event rate. Patients experiencing death were older (56.2 ± 10.7 years vs. 66.4 ± 8.6 years), with a higher prevalence of male gender (56% vs. 87 %, P < 0.05) and diabetes mellitus (23% vs. 36%, P < 0.05). At stress-MPS, patients with event had lower mean values of HRR (53.2 ± 21.3% vs. 61.5 ± 16.4%, P < 0.0001) and higher prevalence of moderate-severe ischemia (24% vs. 8%, P < 0.0001). The best trade-off between sensitivity and specificity for identifying chronotropic incompetence was a HRR <67% with an area under the receiver operating characteristic curve of 0.62. The event free survival was lower in patients with HRR <67% compared to those with HRR ≥67% (log-rank 9.75, P < 0.005). Accordingly, the annualized event rate was 0.006 in patients with HRR <67% and 0.014 in those with HRR ≥67% (P < 0.001). At Cox regression analysis, univariable predictors of all-cause mortality were age, male gender, diabetes mellitus, HRR and moderate-severe ischemia (all P < 0.05). At multivariable analysis age, male gender, HRR and moderate-severe ischemia were independent predictors of all-cause mortality (all P < 0.05). HRR improved the prognostic power of a model including clinical data and MPS findings for the prediction of all-cause mortality, increasing the global chi-square from 76.16 to 82.68 (P < 0.005).

Conclusion. Chronotropic incompetence assessed by HRR evaluation, has independent and incremental prognostic value in predicting all cause of death in patients with suspected CAD undergoing exercise stress-MPS.

Prognostic value of pericoronary adipose tissue and coronary vascular function by cardiac 82Rb PET/CT imaging in patients with suspected coronary artery disease and normal myocardial perfusion imaging

Funding Acknowledgements

Type of funding sources: None.

Introduction

Pericoronary adipose tissue, due to its proximity to coronary arteries, has been proposed contribute to the progression of coronary atherosclerosis.

Purpose

The aim of this study was to evaluate the prognostic value of pericoronary fat thickness (PCFT), coronary artery calcium (CAC) score and myocardial perfusion reserve (MPR) by hybrid 82Rubidium (82Rb) PET/CT imaging in patients with suspected coronary artery disease (CAD) and normal myocardial perfusion imaging (MPI).

Methods

A total of 640 patients without overt CAD and with normal rest-stress 82Rb PET/CT MPI were studied. PCFT was calculated on CT images as the maximum fat thickness (mm) between heart surface and visceral epicardium surrounding the main coronary arteries. CAC score was categorized as 0, <400 or ≥400. MPR was considered reduced when <2. Endpoints events were cardiac death, nonfatal myocardial infarction and coronary revascularization.

Results

During a follow-up of 42 ± 13 months, 29 events occurred (cumulative event rate 5%). Patients with events were older (66 ± 13 vs. 60 ± 13 years, p < 0.01), had higher PCFT (13 ± 2 vs 11 ± 2 mm, p < 0.001), higher prevalence of CAC score ≥400 (48% vs. 21%, p < 0.01), and lower MPR (2.1 ± 0.7 vs. 2.7 ± 0.7, p < 0.001) compared to those without. A higher prevalence of MPR <2 was observed in patients with events (48% vs. 18, p < 0.001) compared to those without. Patients with reduced MPR had higher PCFT compared to those with normal MPR (12 ± 2 vs. 11 ± 1 mm, p < 0.01). A PCFT value of 11.2 mm was the best trade-off between sensitivity and specificity to detect a reduced MPR. Event rate was higher in patients above this threshold compared to those below (8% vs. 1.5%, p < 0.001). At Cox univariate analysis, age (p < 0.05), PCFT >11.2 mm (p < 0.001), CAC score ≥400 (p < 0.01), and MPR <2 (p < 0.001) were predictors of events. At multivariate analysis, only PCFT >11.2 mm and MPR <2 were independent predictors of events (both p < 0.01). At incremental analysis, adding PCFT >11.2 to a model including clinical data and MPR <2 increased the global chi-square from 26 to 35 (p < 0.01). Classification tree analysis produced 3 terminal groups. For patients with MPR <2, no further split was needed (event rate 12% vs. 3%, p < 0.001). On the contrary, patients with MPR ≥2 were further stratified by PCFT (event rate 7% in patients with and 0.3% in those without (p < 0.001) PCFT >11.2.

Conclusions

In patients with suspected CAD and normal stress MPI, coronary vascular dysfunction and high PCFT are associated with increased cardiac risk. PCFT could help in identifying patients at higher risk of events. Combined evaluation of anatomical and functional vascular abnormalities by 82Rb PET/CT might allow a better risk stratification.

Haemochromatosis Gene (HFE) Polymorphisms and Migraine: An Association Study

Several studies have suggested that iron metabolism may be involved in the pathogenesis of migraine. Using a case-control design, we performed an association study in a cohort of Italian migraine patients to evaluate whether a particular allele or genotype of the haemochromatosis gene ( HFE) would modify the occurrence and clinical features of the disease. We genotyped 256 migraine patients and 237 healthy age-, sex- and ethnicity-matched controls for the C282Y and H63D polymorphisms of the HFE gene. Phenotype and allele frequencies of both polymorphisms were similarly distributed in migraine patients and controls. The patients carrying the DD genotype of the H63D polymorphism showed a later age at onset of the disease and an increased number of migraine attacks. Our data suggest that the HFE gene is not a major disease gene for migraine. However, the H63D polymorphism of the HFE gene may be considered a modifying genetic factor in migraine.

Reclassification of cardiovascular risk by myocardial perfusion imaging in diabetic patients with abnormal resting electrocardiogram

BACKGROUND AND AIMS

Despite an extensive use of stress myocardial perfusion single-photon emission computed tomography (MPS), no study addressed the role of perfusion imaging in diabetic patients with abnormal resting electrocardiogram (ECG). We compared analytical approaches to assess the added value of stress MPS variables in estimating coronary heart disease outcomes in diabetic patients with abnormal resting ECG.

METHODS AND RESULTS

A total of 416 patients with diabetes and abnormal resting ECG who underwent stress MPS were prospectively followed up after the index study. The end point was the occurrence of a major cardiac event, including cardiac death and nonfatal myocardial infarction. At the end of follow-up (median 58 months), 42 patients experienced events. MPS data increased the predictive value of a model including traditional cardiovascular risk factors and left ventricular (LV) ejection fraction (likelihood ratio χ² from 17.54 to 24.15, p < 0.05, with a C statistic of 0.72, 95% confidence interval: 0.65-0.79). The addition of MPS data resulted in reclassification of 25% of the sample with a net reclassification improvement of 0.20 (95% confidence interval: 0.05-0.36). Overall, 63 patients were reclassified to a lower risk category, with a 5-year event rate of 3.5%, and 40 patients were reclassified to a higher risk category, with a 5-year event rate of 20%.

CONCLUSION

The addition of MPS findings to a model based on traditional cardiovascular risk factors and LV ejection fraction improves risk classification for incident cardiac events in diabetic patients with abnormal resting ECG.

Screening for mutations in the ISL1 gene in patients with thyroid dysgenesis

CONTEXT

Congenital hypothyroidism (CH) is a common endocrine disorder with an incidence of 1:3000- 4000 newborns. In 80-85% of cases, CH is caused by defects in thyroid organogenesis, resulting in absent, ectopically located, and/or severely reduced gland, all conditions indicated as "thyroid dysgenesis" (TD). A higher prevalence of congenital heart diseases has been documented in children with CH compared to the general population. This association suggests a possible pathogenic role of genes involved in both heart and thyroid development. Among these, it can be included Isl1, a transcription factor containing a LIM homeodomain that is expressed in both thyroid and heart during morphogenesis.

OBJECTIVE

In the present study, we investigate the role of ISL1 in the pathogenesis of TD.

SETTINGS AND PATIENTS

By single stranded conformational polymorphism, we screened for mutations the entire ISL1 coding sequence in 96 patients with TD and in 96 normal controls.

RESULTS

No mutations have been found in patients and controls.

CONCLUSION

Our data indicate that, despite the relevant role of ISL1 in thyroid and heart morphogenesis, mutations in its coding region are not associated with TD in our group of patients.

Mutations in TAZ/WWTR1, a co-activator of NKX2.1 and PAX8 are not a frequent cause of thyroid dysgenesis

AIM

In 80-85% of cases, congenital hypothyroidism is associated with thyroid dysgenesis (TD), but only in a small percentage of cases mutations in thyroid transcription factors (NKX2.1, PAX8, FOXE1, and NKX2.5) have been associated with the disease. Several studies demonstrated that the activity of the transcription factors can be modulated by the interaction with other proteins, such as coactivators and co-repressors, and TAZ (transcriptional co-activator with PDZ-binding motif or WWTR1) is a co-activator interacting with both NKX2.1 and PAX8. In the present study we investigate the role of TAZ in the pathogenesis of TD.

MATERIAL AND METHODS

By Single Stranded Conformational Polymorphism, we screened the entire TAZ coding sequence for mutations in 96 patients with TD and in 96 normal controls.

RESULTS

No mutations were found in patients and controls, but we found several polymorphisms in both groups. No significant differences could be demonstrated in the prevalence of the mutations between patients and controls.

CONCLUSIONS

Our data indicate that TAZ mutations are not a cause of TD in the series of patients studied.

Vagal nerve stimulator: a new approach to medically refractory epilepsy

Repetitive vagal nerve stimulation (VNS) is a new, FDA-approved treatment for medically refractory epilepsy. The device is implanted subcutaneously in the left chest and sends intermittent impulses to the left vagus nerve through communicating leads. Twelve patients have been implanted to date. The ages of the patients range from 8 to 36 years and the average followup at this point is five months. Five patients have achieved a greater than 50 percent reduction in seizure frequency with no serious adverse effects.

Psychopharmacologic treatment of acquired attention disorders in children with brain injury

This investigation examined the efficacy of psychostimulant therapy in alleviating neurobehavioral dysfunction attendant to pediatric brain injury. The most commonly reported neurobehavioral sequelae associated with head injury in the pediatric population involve deficits along the attentional matrix. This is also the most common objectively documented neurobehavioral finding among children as well as adults. There are several investigations in the adult literature which have employed the use of psychostimulants in treating both psychiatric and neuropsychological residua associated with head injury. Overall, the results of these studies are equivocal, but suggest a beneficial impact on general functioning. The present prospective investigation utilized a double-blind, placebo-controlled, cross-over experimental design to examine the efficacy of methylphenidate in treating children with acquired attentional disorders secondary to brain injury. A cohort of 14 children with varying degrees of head injury were recruited for participation. As expected, differences between drug and placebo conditions uniformly achieved statistical significance. Additionally, there were no differences in performance between baseline and placebo conditions on neurobehavioral tasks of attention and concentration. Current findings suggest that methylphenidate (and probably other psychostimulants such as Cylert, Adderal, Wellbutrin and dextroamphetamine sulfate) is an extremely effective agent in treating attentional disorders secondary to brain injury in children.

The importance of cerebral ischemia during carotid endarterectomy

The importance of cerebral ischemia produced by carotid clamping during carotid endarterectomy remains controversial. In an effort to determine the importance of cerebral ischemia during carotid endarterectomy, 369 patients undergoing 431 consecutive carotid endarterectomies were studied by Xenon-133 (133Xe) clearance and electroencephalogram (EEG) monitoring. None of the patients was shunted during the procedures. The severity of ischemia as indicated by 133Xe clearance from the ipsilateral hemisphere during 20 to 30 minutes of carotid occlusion did not predict the appearance of complications in this group of patients (chi 2 = 1.417; P = 0.841). There was a highly significant relationship between the depth of cerebral ischemia as demonstrated by 133Xe clearance and the appearance of abnormalities on the EEG (chi 2 = 42.043, P less than 0.0001). In the subgroup of patients developing abnormalities as shown by EEG, there was a negative correlation (chi 2 = 17.495; P less than 0.002) between reduction in blood flow and the appearance of complications, in that the higher the blood flow during occlusion the more likely the patient developing EEG changes would develop complications.