Elevated troponin I level assessed by a new high-sensitive assay and the risk of poor outcomes in patients with acute heart failure

The role of urine chloride in acute heart failure

In our retrospective study, we aimed to investigate the relationship between urinary chloride (uCl-) and selected clinical and laboratory biomarkers, renal function, and patient outcomes in the acute heart failure (AHF) population. We divided 248 adult patients (≥ 18 years) with AHF into two groups: low uCl- (< 115 mmol/L) and high uCl-. The mean age of the patient group was 70.2 ± 12.6, and 182 patients were male (73.4%). Clinical endpoints included in-hospital mortality, one-year mortality, and a composite endpoint of one-year mortality and rehospitalization for heart failure. Patients were followed up for at least one year. Relevant clinical and baseline biomarker data were collected, including markers concerning inflammation, liver and kidney function, perfusion and congestion, iron status, cardiac remodeling, gasometry, renin and aldosterone. Low uCl- was associated with worse in-hospital outcomes, including higher in-hospital mortality (7.7% vs. 1.4%, p = 0.014), the need for inotropic support (20.19% vs. 2.08%, p ≤ 0.001), worsening of HF during therapy (17.31% vs. 4.86%, p ≤ 0.001), and the need for treatment in an intensive cardiac care unit (33.65% vs. 15.28%, p ≤ 0.001). Low uCl- was a significant predictor of one-year mortality (40.4% vs. 16.7%, p < 0.05) and the composite outcome (HR 2.42, 95% CI 1.43-4.08, p < 0.001). In the multivariable analysis, uCl- was independently associated with the risk of one-year mortality (HR 0.92, 95% CI 0.87-0.98, p < 0.05) and the composite outcome (HR 0.95, 95% CI 0.92-0.99, p < 0.05). Our findings suggest that low uCl- is a marker of more advanced heart failure, activation of the renin-angiotensin-aldosterone system and is related to worse one-year outcomes.

Machine Learning Approach to Understand Worsening Renal Function in Acute Heart Failure

Acute heart failure (AHF) is a common and severe condition with a poor prognosis. Its course is often complicated by worsening renal function (WRF), exacerbating the outcome. The population of AHF patients experiencing WRF is heterogenous, and some novel possibilities for its analysis have recently emerged. Clustering is a machine learning (ML) technique that divides the population into distinct subgroups based on the similarity of cases (patients). Given that, we decided to use clustering to find subgroups inside the AHF population that differ in terms of WRF occurrence. We evaluated data from the three hundred and twelve AHF patients hospitalized in our institution who had creatinine assessed four times during hospitalization. Eighty-six variables evaluated at admission were included in the analysis. The k-medoids algorithm was used for clustering, and the quality of the procedure was judged by the Davies–Bouldin index. Three clinically and prognostically different clusters were distinguished. The groups had significantly (p = 0.004) different incidences of WRF. Inside the AHF population, we successfully discovered that three groups varied in renal prognosis. Our results provide novel insight into the AHF and WRF interplay and can be valuable for future trial construction and more tailored treatment.

Novel Phenotyping for Acute Heart Failure—Unsupervised Machine Learning-Based Approach

Acute heart failure (AHF) is a life-threatening, heterogeneous disease requiring urgent diagnosis and treatment. The clinical severity and medical procedures differ according to a complex interplay between the deterioration cause, underlying cardiac substrate, and comorbidities. This study aimed to analyze the natural phenotypic heterogeneity of the AHF population and evaluate the possibilities offered by clustering (unsupervised machine-learning technique) in a medical data assessment. We evaluated data from 381 AHF patients. Sixty-three clinical and biochemical features were assessed at the admission of the patients and were included in the analysis after the preprocessing. The K-medoids algorithm was implemented to create the clusters, and optimization, based on the Davies-Bouldin index, was used. The clustering was performed while blinded to the outcome. The outcome associations were evaluated using the Kaplan-Meier curves and Cox proportional-hazards regressions. The algorithm distinguished six clusters that differed significantly in 58 variables concerning i.e., etiology, clinical status, comorbidities, laboratory parameters and lifestyle factors. The clusters differed in terms of the one-year mortality (p = 0.002). Using the clustering techniques, we extracted six phenotypes from AHF patients with distinct clinical characteristics and outcomes. Our results can be valuable for future trial constructions and customized treatment.

Biomarkers of Myocardial Injury and Remodeling in Heart Failure

With its complicated pathophysiology, high incidence and prevalence, heart failure remains a major public concern. In hopes of improving diagnosis, treatment and prognosis, the utility of many different biomarkers is researched vigorously around the world. In this review, biomarkers of myocardial remodeling and fibrosis (galectin-3, soluble isoform of suppression of tumorigenicity 2, matrix metalloproteinases, osteopontin, interleukin-6, syndecan-4, myostatin, procollagen type I C-terminal propeptide, procollagen type III N-terminal propeptide, vascular endothelial growth factor, nitric oxidase synthetase and asymmetric dimethylarginine), myocyte injury (heart-type fatty acid-binding protein, glutathione S-transferase P1 and heat shock protein 60), as well as iron metabolism (ferritin, transferrin saturation, soluble transferrin receptor and hepcidin), are considered in terms of possible clinical applicability and significance. Our short review consists of a summary of the aforementioned cardiovascular biomarkers’ clinical relevance and perspectives.

High sensitivity Troponins In Patients with elevated prohormone of beta natriuretic peptide and acute heart failure (HIGH TRIP Trial)

In patients presented to emergency rooms, Pro hormone of Natriuretic Peptide (Pro BNP) essay is overly sensitive test to rule out heart failure but less specific in predicting outcomes in follow-ups, in this study we ought to find the added value of High Sensitivity cardiac Troponin I (Hs-cTn I), in patients presented acutely with heart failure and its impact on mortality when Pro BNP is highly elevated. Prospective cohort study, inclusion criteria were age above 18 and clearly positive NT Pro BNP > 1000 pg/ml, with 12 months follow up period, primary end point was mortality from heart failure, secondary endpoint was need for rehospitalization. 95 patients were enrolled, divided into overt and non-overt pulmonary edema groups. Mean (Pro BNP) was 6184 and 5927 pg/ml and mean (Hs-cTn I) were 19.27 and 0.17 ng/ml respectively, Mean Ejection fraction was 48 ± 7 and 47 ± 7 for each group sequentially. Mortality rate was 4 (13%) in the higher Hs-c Tn I group, and 1 (1.6%) in the low troponin level group p = .03, odd ratio was 8.5, 95% CI (0.9-80). Need for re-hospitalization was present in 12 (38%) Vs 7 (8%) patients, p = .0081, odd ratio 4.8, 95% CI (1.7-14.2). In COX proportional hazard analysis, only Hs-cTn I was a significant predictor of poor outcome in this high-risk cohort with p = 0.0001. Adding (Hs-cTrop I) assay to the panel of laboratory testing, in patients presented to ER with acute heart failure and with high Pro-BNP > 1000, may further predicts mortality and rehospitalization rate.

Spot urine sodium in acute heart failure: differences in prognostic value on admission and discharge

AIMS

Most studies examined spot urine sodium's (sUNa⁺ ) prognostic utility during the early phase of acute heart failure (AHF) hospitalization. In AHF, sodium excretion is related to clinical status; therefore, we investigated the differences in the prognostic information of spot UNa⁺ throughout the course of hospitalization for AHF (admission vs. discharge).

METHODS AND RESULTS

The study population were AHF patients (n = 172), who survived the index hospitalization. We compared the relationship between early (on admission, at 24 and 48 h) and discharge sUNa⁺ measurements with post-discharge study endpoints: composite of 1 year all-cause mortality and AHF rehospitalization (with time to first event analysis) as well as with each event in separation. There were 49 (28.5%) deaths, 40 (23.3%) AHF rehospitalizations, while the composite endpoint occurred in 69 (40.1%) during 1 year follow-up. The sUNa⁺ had prognostic significance for the composite endpoint when assessed on admission, at 24 and at 48 h: hazard ratios (HRs) with 95% confidence intervals (CIs) (per 10 mmol/L) were 0.88 (0.82-0.94); 0.87 (0.81-0.91); 0.90 (0.84-0.96), all P < 0.005. In contrast to early, active decongestion phase, discharge sUNa⁺ had no prognostic significance HR (95% CI) (per 10 mmol/L): 0.99 (0.93-1.06) P = 0.79 for the composite endpoint, which was independent from the dose of oral furosemide prescribed at that timepoint (average causal mediation effects: -0.38; P = 0.71). Similarly, discharge sUNa⁺ was neither associated with 1 year mortality HR (95% CI) (per 10 mmol/L): 0.97 (0.89-1.05) P = 0.48 nor with AHF rehospitalizations HR (95% CI) (per 10 mmol/l): 1.03 (0.94-1.12), P = 0.56. The comparison of longitudinal profiles of sUNa⁺ during hospitalization showed significantly higher values within the early, active decongestive phase in those who did not experience composite endpoint when compared with those who did: admission: 94 ± 34 vs. 76 ± 35; Day 1: 85 ± 36 vs. 65 ± 37; Day 2: 84 ± 37 vs. 67 ± 35, all P < 0.005 (mmol/L), respectively. There was no difference between those groups in discharge sUNa⁺ : 73 ± 35 vs. 70 ± 35 P = 0.82 (mmol/L).

CONCLUSIONS

Spot UNa⁺ assessed at early phase of hospitalization and at discharge have different prognostic significance, which confirms that it should be always interpreted along with clinical context.

Distinct clinical phenotypes of congestion in acute heart failure: characteristics, treatment response, and outcomes

Aims

Patients with acute heart failure (AHF) are included into clinical trials regardless of differences in baseline clinical characteristics. The aim of this study was to assess patients with AHF according to the presence of central and/or peripheral congestion at hospital admission and evaluate treatment response and outcomes in studied phenotypes.

Methods and results

We investigated retrospectively 352 patients (mean age: 68 ± 13 years, 77% men) hospitalized due to AHF with the signs of congestion on admission. Patients were divided according to the type of signs of congestion into three groups: A, isolated pulmonary congestion (n = 52, 15%); B, isolated peripheral congestion (n = 31, 9%); and C, signs of mixed (peripheral and central) congestion (n = 269, 76%). Patients from Group A had lower concentration of urea, bilirubin, and gamma‐glutamyl transferase whereas higher level of haematocrit, albumin, and leukocytes on admission. The highest baseline N‐terminal pro‐B‐type natriuretic peptide level (median: 4113 vs. 3634 vs. 6093 pg/mL) and percentage of patients with chronic heart failure (56 vs. 58 vs. 74%; A vs. B. vs. C, respectively, all P < 0.01) were observed in Group C. There were no differences in terms of demographics, co‐morbidities, left ventricular ejection fraction, and applied treatment between studied groups. Patients from Group A had the highest systolic blood pressure on admission (145 ± 37 vs. 122 ± 20 vs. 130 ± 29 mmHg) and the biggest decrease in systolic blood pressure [−22 (−45 to −4) vs. −2 (−13 to 2) vs. −10 (−25 to 0) mmHg] and heart rate [−16 (−35 to −1.5) vs. −1 (−10 to 5) vs. −7 (−20 to 0) b.p.m.] with the lowest weight change [−1.0 (−1.0 to 0) vs. −2.9 (−3.8 to −0.9) vs. −2.0 (−3.0 to −1.0) kg; all P < 0.01] after 48 h of hospitalization. There were differences in short‐term and long‐term outcomes with favourable results in Group A. Group A experienced less frequent in‐hospital heart failure worsening during the first 48 h (4 vs. 23 vs. 7%), had shorter length of hospital stay [6 (5–8) vs. 7 (5–11) vs. 7 (6–11) days], and had lower 1 year all‐cause mortality (12 vs. 28 vs. 29%; all P < 0.05). Presence of peripheral congestion on admission was independent predictor for all‐cause mortality within 1 year [hazard ratio (95% confidence interval): 2.68 (1.06–6.79); P = 0.04].

Conclusions

Patterns of congestion in AHF are associated with differences in clinical characteristics, treatment response, and outcomes. It needs to be considered once planning clinical trials in AHF.

Real-time three-dimensional echocardiography predicts cardiotoxicity induced by postoperative chemotherapy in breast cancer patients

BACKGROUND

The anthracycline chemotherapeutic drugs are cardiotoxic. Studies have found some indicators related to cardiotoxicity. However, there is currently no accurate indicator that can predict cardiac toxicity early.

AIM

To explore the diagnostic value of real-time three-dimensional echocardiography (RT3DE) in predicting cardiac toxicity in breast cancer patients undergoing chemotherapy.

METHODS

Female breast cancer patients who underwent radical mastectomy and postoperative chemotherapy at the Affiliated Hanzhou First People’s Hospital, Zhejiang University School of Medicine were recruited. All patients were routinely administered with chemotherapy for four cycles (T1-T4) after surgery. Two-dimensional (2D) echocardiography, RT3DE, and serological examinations were performed after each cycle of chemotherapy. Patients were divided into a toxic group and a non-toxic group based on whether patients had Δ left ventricular ejection fraction > 10% after one year of chemotherapy. Repeated measurement analysis of variance was used to compare the changes in 2D echocardiographic indicators, serological indicators, and RT3DE indicators before and after chemotherapy. Multivariate logistic regression was used to identify independent predictive indicators for cardiac toxicity in postoperative chemotherapy patients. Receiver operating characteristics (ROC) curve analysis was performed to analyze the diagnostic value of potential indicators in the diagnosis of cardiotoxicity.

RESULTS

A total of 107 female breast cancer patients were included in the study. T4 maximum peak velocity in early diastole (E peak)/mitral annulus lateral tissue Doppler (e' peak) (E/e'), serological indicators [T4 cardiac troponin I (cTnI) and T4 pro-brain natriuretic peptide (Pro-BNP)], T3 minimum left atrial volume (LAV), T4 LAVmin, T3 LAV before the start of the P wave (LAVprep), and T4 LAVprep in the toxicity group were significantly higher than those in the non-toxic group. Multivariate logistic regression found that T4 cTnI, T4 Pro-BNP, T3 LAVmin, T4 LAVmin, T3 LAVprep, and T4 LAVprep had potential predictive value for cardiac toxicity (P < 0.05). ROC results showed that T4 LAVmin had the highest accuracy for diagnosing cardiac toxicity [area under the curve (AUC) = 0.947; sensitivity = 78.57%; specificity = 94.62%], followed by T4 LAVprep (AUC = 0.899; sensitivity = 100%; specificity = 66.67%). The accuracies of LAVprep and LAVprep in predicting cardiac toxicity were higher than those of T3 LAVmin and T3 LAVprep.

CONCLUSION

RT3DE of left atrial volume can be used to predict the cardiotoxicity caused by chemotherapy, and it is expected to guide the clinical adjustment of dose and schedule in time.

High-sensitivity cardiac troponin T 30 days all-come mortality in patients with acute heart failure. A Propensity Score-Matching Analysis Based on the EAHFE Registry. TROPICA4 Study

BACKGROUND

Acute heart failure (AHF) patients with high troponin levels have a worse prognosis. High-sensitive troponin T (hs-TnT) has been used as a tool to stratify prognosis in many scales but always as a qualitative and not as a quantitative variable.

OBJECTIVES

The main objective of this study was to determine the best hs-TnT cut-off for prediction of 30-day all-cause mortality.

METHODS

The EAHFE registry, a prospective follow-up cohort of patients with AHF, was analysed. We performed a propensity score analysis of the optimal hs-TnT cut-off point previously determined by receiver operating characteristic (ROC) curve analysis.

RESULTS

Of the 13 791 patients in the EAHFE cohort, we analysed 3190 patients in whom hs-TnT determination was available. The area under the ROC curve for 30-day all-cause mortality was 0.70 (CI95% 0.68 to 0.71; P < .001), establishing an optimal cut-off of hs-TnT of 35 ng/L. The sensitivity and specificity of this cut-off were 76.2 and 55.5%, respectively, with a negative predictive value (NPV) of 95.3%. A propensity score was made with 34 variables showing differences based on the cut-off of 35 ng/L for hs-TnT. In the analysis of the population obtained with the propensity score, patients with hs-TnT > 35 ng/L showed a greater 30-day all-cause mortality, with a HR of 2.95 (CI95% 1.83-4.75; P < .001). External validation reported similar results.

CONCLUSIONS

An hs-TnT value of 35 ng/L is an adequate cut-off to evaluate the prediction of 30-day all-cause mortality with a NPV of 95.3%.

Hepatorenal dysfunction identifies high-risk patients with acute heart failure: insights from the RELAX-AHF trial

AIMS

Episodes of acute heart failure (AHF) may lead to end-organ dysfunction. In this post hoc analysis of the Relaxin in Acute Heart Failure trial, we used the MELD-XI (Model of End-Stage Liver Dysfunction) score to examine hepatorenal dysfunction in patients with AHF.

METHODS AND RESULTS

On admission, the MELD-XI score was elevated (abnormal) in 918 (82%) patients, with 638 (57%) having isolated renal dysfunction (creatinine > 1 mg/dL), 73 (6.5%) isolated liver dysfunction (bilirubin > 1 mg/dL), and 207 (18.5%) coexisting dysfunction of the kidneys and the liver (both creatinine and bilirubin > 1 mg/dL). The percentage of patients with elevated MELD-XI score remained constant through a 60 day follow-up, as we observed a gradual decrease of liver dysfunction prevalence, counterbalanced by an increase in renal dysfunction. Serelaxin treatment was associated with a lower MELD-XI score on Day 2 and Day 5 (both P < 0.05), but this difference vs. placebo disappeared during longer follow-up. In the multivariable model, an elevated MELD-XI score on admission was associated with higher 180 day mortality: hazard ratios (95% confidence interval) for cardiovascular death were 3.10 (1.22-7.87), and for all-cause death 2.47 (1.19-5.15); both P < 0.05. The addition of the MELD-XI score to a prespecified prognostic model increased the discrimination of the model for all-cause death, but the increment in the C-index was only modest: 0.013 (P = 0.02).

CONCLUSIONS

In patients with AHF, hepatorenal dysfunction is prevalent and related to poor outcome. The MELD-XI score is a useful prognosticator in AHF.

Multi-organ dysfunction/injury on admission identifies acute heart failure patients at high risk of poor outcome

BACKGROUND

Clinical consequences of an interplay between dysfunction/injury of different end-organs in acute heart failure (AHF) remain unknown.

METHODS AND RESULTS

In 284 consecutive AHF patients, end-organ dysfunction/injury was defined as cardiac [troponin I level above the upper reference limit (URL, > 0.056 ng/mL)], kidney (estimated glomerular filtration rate < 60 mL/min/1.73 m² ), and liver [at least one of the following: aspartate transaminase (AST)/alanine transaminase (ALT) > 3 times the URL (> 114 IU/L and > 105 IU/L for AST and ALT, respectively), bilirubin above the URL (> 1.3 mg/mL), albumin below the lower reference limit (< 3.5 mg/dL)]. The primary endpoints were early (within first 48 h) in-hospital worsening of heart failure and 1-year all-cause mortality. On admission, cardiac, kidney, liver dysfunction/injury were present in 38%, 50%, and 54% of patients, respectively. Patients were classified as having 0, 1, 2, or 3 organ injury/dysfunction (17%, 36%, 35%, and 12% of patients, respectively). Baseline clinical characteristics and co-morbidity profile were similar across groups. Patients with three organ dysfunction/injury had the worst 1-year survival rate [46%; hazard ratio (HR) with 95% confidence interval (CI) vs. patients without organ dysfunction: 6.75 (2.52-18.13), those with two (67%; HR 3.54, 95% CI 1.38-9.08), one (84%; HR 1.58, 95% CI 0.58-4.30), or no organ dysfunction/injury (90%); P < 0.01]. Worsening of heart failure was more frequent in patients with three and two vs. those with one or no organ dysfunction/injury (37% vs. 38% vs. 23% vs. 21%, P < 0.05).

CONCLUSIONS

In patients with AHF, dysfunction/injury of > 1 end-organ dysfunction/injury identifies patients at the highest risk of poor outcomes.

Patterns of dyspnoea onset in patients with acute heart failure: clinical and prognostic implications

Aims

Despite attempts to improve the management of patients with acute heart failure (HF), virtually all therapeutic agents investigated in large clinical trials failed to show any consistent reduction in mortality and morbidity. Complexity of the clinical syndrome of acute HF seems to be likely an underlying explanation. Traditionally, clinical trials studied mixed patient populations with acute HF, and only recently, better clinical characterization of patients has been proposed. Dyspnoea is the most common presenting symptom related to hospital admission for acute HF. Whether in patients with acute HF, the pattern of symptoms onset preceding hospital admission is associated with clinical characteristics, and the outcomes have not yet been established.

Methods and results

We investigated 137 patients (mean age: 65 ± 13 years; 80% men) hospitalized due to acute HF with dyspnoea as major reported symptom, who were divided according to the time of its onset into those with acute (n = 98) vs. subacute (n = 39) onset (i.e. within 7 days vs. >7 days preceding hospital admission, respectively). On admission, the former group presented higher blood pressure (138 ± 33 vs. 121 ± 32 mmHg), more often moderate–severe pulmonary congestion (33 vs. 8%), and lower bilirubin level [1.07 (0.72–1.60) vs. 1.27 (0.87–2.06); P < 0.05 in all comparisons]. There were no other differences in baseline clinical characteristics and laboratory indices. Higher percentage of patients with an acute dyspnoea onset reported marked/moderate dyspnoea relief after 6 (18% vs. 7%), 24 (59% vs. 24%), and 48 h (80% vs. 46% assessed as an improvement of at least 5 points in self‐reported 10‐point Likert scale; P < 0.05 in all time points). In patients with an acute onset of dyspnoea after 48 h, a decrease of N‐terminal pro BNP was more frequently observed (83% vs. 65%), and the levels of endothelin‐1 were more reduced [−1.1 (−2.9–0.03) vs 0.4 (−2.2–1.4); all P < 0.05]. Patients with acute onset experienced less in‐hospital HF worsening (13% vs. 40%, P = 0.001), and 1 year cardiovascular mortality was significantly lower (20% vs. 41%, P = 0.01). On the multivariable analysis, subacute pattern of dyspnoea was independent predictor of 12 month cardiovascular mortality in patients with acute HF after adjusting for other prognostic factors: systolic blood pressure, urea, and HF de novo [hazard ratio (95% confidence interval): 2.32 (1.13–4.75), P = 0.02].

Conclusions

In patients with acute HF, the pattern of symptoms onset is associated with baseline differences in clinical characteristics, biomarker profile, response to standard treatment, and the long‐term outcomes. This is relevant information for planning future clinical trials.

Increased blood lactate is prevalent and identifies poor prognosis in patients with acute heart failure without overt peripheral hypoperfusion

AIMS

Lactate is produced by anaerobic metabolism and may reflect inadequate tissue perfusion in conditions such as acute heart failure (AHF). We evaluated the prevalence and clinical significance of elevated blood lactate on admission in patients with AHF.

METHODS AND RESULTS

We enrolled 237 patients with AHF (mean age 67 ± 12 years; 70% men) presenting without overt clinical evidence of peripheral hypoperfusion ('warm haemodynamic profile'). Median (upper and lower quartiles) blood lactate on admission was 1.8 (1.5; 2.4) mmol/L; 103 (43%) patients had an elevated blood lactate (≥2 mmol/L). Patients with an elevated lactate had higher blood high-sensitivity troponin I [15.4 (8.5; 26.1) vs. 9.9 (4.3; 19.6) pg/mL], aspartate aminotransferase [28 (20; 44) vs 24 (19; 36) IU/L] and endothelin-1 (12.1 ± 6.2 vs. 9.3 ± 3.9 pg/mL) (all P < 0.05). In this group plasma concentration of neutrophil gelatinase-associated lipocalin increased during the first 48 h, whereas values fell for those with normal baseline lactate [1.9 (-3.2; 9.7) vs. -1.3 (-13.9; 5.6) μg/dL; P < 0.05). One-year mortality was higher amongst patients with an elevated blood lactate (36% vs. 21%; P < 0.05). After adjustment for other well-established prognostic variables, blood lactate on admission predicted poor outcome (hazard ratio 1.24, 95% confidence interval 1.08-1.41; P < 0.05).

CONCLUSIONS

An elevated blood lactate on admission is common in AHF patients without overt clinical evidence of peripheral hypoperfusion and is associated with markers of organ dysfunction/damage and a worse prognosis.

A portable prototype magnetometer to differentiate ischemic and non-ischemic heart disease in patients with chest pain

BACKGROUND

Magnetocardiography (MCG) is a non-invasive technique used to measure and map cardiac magnetic fields. We describe the predictive performance of a portable prototype magnetometer designed for use in acute and routine clinical settings. We assessed the predictive ability of the measurements derived from the magnetometer for the ruling-out of healthy subjects and patients whose chest pain has a non-ischemic origin from those with ischemic heart disease (IHD).

METHODS

MCG data were analyzed from a technical performance study, a pilot clinical study, and a young healthy reference group. Participants were grouped to enable differentiation of those with IHD versus non-IHD versus controls: Group A (70 IHD patients); Group B (69 controls); Group C (37 young healthy volunteers). Scans were recorded in an unshielded room. Between-group differences were explored using analysis of variance. The ability of 10 candidate MCG predictors to predict normal/abnormal cases was analyzed using logistic regression. Predictive performance was internally validated using repeated five-fold cross-validation.

RESULTS

Three MCG predictors showed a significant difference between patients and age-matched controls (P<0.001); eight predictors showed a significant difference between patients and young healthy volunteers (P<0.001). Logistic regression comparing patients with controls yielded a specificity of 35.0%, sensitivity of 95.4%, and negative predictive value for the ruling-out of IHD of 97.8% (area under the curve 0.78).

CONCLUSION

This analysis represents a preliminary indication that the portable magnetometer can help rule-out healthy subjects and patients whose chest pain has a non-ischemic origin from those with IHD.