Development and Temporal Validation of a Machine Learning Model to Predict Clinical Deterioration

OBJECTIVES

Early warning scores detecting clinical deterioration in pediatric inpatients have wide-ranging performance and use a limited number of clinical features. This study developed a machine learning model leveraging multiple static and dynamic clinical features from the electronic health record to predict the composite outcome of unplanned transfer to the ICU within 24 hours and inpatient mortality within 48 hours in hospitalized children.

METHODS

Using a retrospective development cohort of 17 630 encounters across 10 388 patients, 2 machine learning models (light gradient boosting machine [LGBM] and random forest) were trained on 542 features and compared with our institutional Pediatric Early Warning Score (I-PEWS).

RESULTS

The LGBM model significantly outperformed I-PEWS based on receiver operating characteristic curve (AUROC) for the composite outcome of ICU transfer or mortality for both internal validation and temporal validation cohorts (AUROC 0.785 95% confidence interval [0.780-0.791] vs 0.708 [0.701-0.715] for temporal validation) as well as lead-time before deterioration events (median 11 hours vs 3 hours; P = .004). However, LGBM performance as evaluated by precision recall curve was lesser in the temporal validation cohort with associated decreased positive predictive value (6% vs 29%) and increased number needed to evaluate (17 vs 3) compared with I-PEWS.

CONCLUSIONS

Our electronic health record based machine learning model demonstrated improved AUROC and lead-time in predicting clinical deterioration in pediatric inpatients 24 to 48 hours in advance compared with I-PEWS. Further work is needed to optimize model positive predictive value to allow for integration into clinical practice.

Study of the Prevalence of Congenital Coronary Anomalies of Origin from the Opposite or Non-coronary Sinus in patients undergoing Invasive Coronary Angiography

OBJECTIVES

1. To study the incidence and clinical features of patients with Congenital Coronary Anomalies of Origin from Oppossite or Non-coronary Sinus; 2. To study the course of these Anomalous Coronary Artery Origins with CT Coronary Angiography.

METHODS

A Cross Sectional Observation study was conducted at Department of Cardiology, in a tertiary Hospital for a period of 3 years. Patients undergoing Coronary Angiography (CAG) were screened and patients having Anomalous Coronary Origin from the Opposite or Non-Coronary Sinus of Valsalva were selected. CT Cronary Angiography was done in all such patients and the course of the anomalous artery was studied.

RESULTS

During the 3 years period of study, total of 5241 CAGs were conducted of which 42 (0.8%) patients were found to have Anomalous Coronary Artery Origin as per the inclusion criteria. Out of the 42 cases, Anomalous origin of RCA from Left Corornary Cusp was the commonest with 23(0.43%) cases, followed by Anomalous Origin of LCX from Right Coronary or RCC with 17 (0.32%) cases. Other anomalies of origin were quite rare (n=2) which included Anomalous origin of Left Main from RCA (n=1) and Dual origin of LAD (n=1). CT Coronary Angiography showed that of the 23 patients with Anomalous Origin of RCA from Left side,27.4% had Inter-Arterial course and 56.1% had Retro-Aortic course. Of the 17 patients with Anomalous Origin of LCX from Right sinus, 88.23% had Retro-Aortic course.

CONCLUSIONS

This study showed that anomalous origin of Coronary Artery from the opposite sinus is quite rare with RCA from Left Sinus and LCX from Right sinus comprised the vast majority of cases. Most of these anomalous Coronaries have on benign course as defined on CT Coronary Angiography. However, it is important to recognize to delineate the origin and course as it can have significant clinical, therapeutic and prognostic implications.

P1930Pharmacodynamic effects of vorapaxar as an add-on antiplatelet therapy in patients with and without diabetes mellitus: the optimizing anti-platelet therapy in diabetes mellitus (OPTIMUS)-5 study

Background

Vorapaxar (Vora) is a protease-activated receptor (PAR)-1 inhibitor which when added to dual antiplatelet therapy (DAPT) in patients with a history of myocardial infarction (MI) or with peripheral arterial (PAD) reduces thrombotic cardiovascular events at the expense of increased bleeding. The efficacy of Vora is enhanced in patients with diabetes mellitus (DM) compared to non-DM. However, the differential pharmacodynamic (PD) effects of Vora in DM vs non-DM patients are unknown. Moreover, although withdrawal of aspirin has emerged as a strategy to reduce bleeding when adjunctive antithrombotic therapies are used, the PD effects of Vora after stopping aspirin in DAPT treated patients is unknown.

Purpose

To assess the PD effects of Vora in addition to standard DAPT as well as in combination with clopidogrel following aspirin withdrawal in patients with and without DM.

Methods

This was a prospective parallel-design PD study conducted in post-MI or PAD patients with and without DM. Patients on DAPT with aspirin (81mg/qd) and clopidogrel (75mg/qd) were divided in two groups according to DM status. Each cohort was treated with Vora (2.5mg/qd) in addition to DAPT (i.e., triple therapy) for 30 days and afterwards stopped aspirin and maintained treatment with Vora plus clopidogrel (i.e., dual therapy) for other 30 days. PD testing using 5 different assays was conducted at 3 time-points: baseline (while on DAPT); after 30 days of triple therapy; after 30 days of dual therapy. The primary endpoint was the non-inferiority of CAT (Collagen-ADP-TRAP)-induced aggregation, a marker of global platelet reactivity, of Vora plus clopidogrel (dual therapy) vs Vora plus DAPT (triple therapy).

Results

The PD population was composed of a total of 64 patients (DM, n=30; non-DM, n=34). Although adding Vora to DAPT significantly reduced CAT-induced aggregation, stopping aspirin was associated with an increase in CAT-induced aggregation in both DM (mean difference=12; 95% CI: 3 to 21; p=0.010) and non-DM (mean difference=10; 95% CI: 4 to 16; p=0.003), thus not meeting the primary endpoint of non-inferiority (Figure). The magnitude of such increase was higher in DM compared with non-DM (p=0.036). Although Vora abolished TRAP-induced aggregation in both DM and non-DM patients, it did not affect markers of clot kinetics including speed of thrombin generation. Aspirin withdrawal was associated with a marked increase in makers sensitive to cyclooxygenase-1 (COX-1) blockade; markers of P2Y12 signaling were higher in DM compared to not DM after aspirin withdrawal.

CAT-induced aggregation

Conclusion

Adjunctive treatment with Vora reduces platelet-mediated thrombogenicity without affecting clot kinetics in both DM and non-DM patients while on DAPT. However, platelet-mediated thrombogenicity is increased after aspirin withdrawal, a phenomenon which is enhanced in DM patients underscoring the pivotal contribution of the COX-1 signaling pathway in these high risk patients.

Acknowledgement/Funding

The study was supported in part by an investigator initiated study grant from Merck

P1934Platelet inhibitory profiles of prasugrel versus ticagrelor in patients with CYP2C19 loss-of-function genotypes undergoing percutaneous coronary intervention: results of a randomized feasibility study

Background

Although clopidogrel is the most widely used P2Y12 inhibitor, loss-of-function (LOF) allelic variants located within the hepatic cytochrome P450 (CYP) 2C19 gene lead to attenuated bioactivation, increased rates of high platelet reactivity (HPR), and worse outcomes in patients undergoing percutaneous coronary intervention (PCI). Drug regulating authorities have suggested using alternative P2Y12 inhibitors (i.e., prasugrel or ticagrelor) in these patients. However, tailoring antiplatelet therapy in clinical practice according to results of genetic testing has been limited due to lack of access to promptly available results. Moreover, there are no head-to-head pharmacodynamic (PD) comparisons of prasugrel vs ticagrelor among patients with CYP2C19 LOF alleles.

Purpose

The aim of this study was to evaluate the feasibility of using rapid genetic testing in clinical practice and to compare the PD effects of prasugrel vs ticagrelor in patients undergoing PCI with CYP2C19 LOF alleles.

Methods

This was a prospective, randomized study conducted in patients with stable coronary artery disease and non-ST elevation acute coronary syndrome scheduled for left heart catheterization (LHC) with the intent to undergo PCI. Patients underwent rapid genetic testing using the Spartan RX assay, which defines CYP2C19 genetic status within 1 hour, allowing patients to be genotyped the same day of their LHC. Patients who were carriers of at least one LOF (*2 or *3) allele were randomized to receive either prasugrel [60mg loading dose (LD) - 10mg/day maintenance dose (MD)] or ticagrelor (180mg LD - 90mg b.i.d MD). Blood samples for PD analysis by VerifyNow were collected at 5 time points: baseline (prior to PCI), 30 minutes, 2 hours, 24 hours (or at hospital discharge whichever came first), and 1–4 weeks post-LD. All patients were treated with aspirin. The primary endpoint of our study was the non-inferiority in platelet reactivity, measured as PRU, at 24 hours of prasugrel vs ticagrelor in LOF allele carriers.

Results

A total of 781 consecutive patients scheduled for LHC were genotyped, of whom 223 (28.5%) were carriers of at least one LOF. Of these, 65 patients underwent PCI and randomized to prasugrel (n=32) vs ticagrelor (n=33). PRU levels at 24 hours were 33 vs 36 (prasugrel vs ticagrelor; mean difference = −3; 95% CI: −28 to 22; p=0.814) meeting the primary endpoint of non-inferiority. Both prasugrel and ticagrelor significantly reduced PRU to a similar extent with no differences between groups at all other time points (Figure). Accordingly, HPR rates were low and similar between groups.

PRU by VerifyNow

Conclusion

Rapid genetic testing using the Spartan assay is feasible providing results in a timely fashion in a real-world clinical practice of patients undergoing PCI. Among patients with CYP2C19 LOF carrier status, prasugrel and ticagrelor are associated with similar levels of platelet inhibition.

Acknowledgement/Funding

Genetic testing was provided by Spartan RX

Incorporation of macrophages into engineered skeletal muscle enables enhanced muscle regeneration

Adult skeletal muscle has a robust capacity for self-repair, owing to synergies between muscle satellite cells and the immune system. In vitro models of muscle self-repair would facilitate the basic understanding of muscle regeneration and the screening of therapies for muscle disease. Here, we show that the incorporation of macrophages into muscle tissues engineered from adult-rat myogenic cells enables near-complete structural and functional repair after cardiotoxic injury in vitro. First, we show that-in contrast with injured neonatal-derived engineered muscle-adult-derived engineered muscle fails to properly self-repair after injury, even when treated with pro-regenerative cytokines. We then show that rat bone-marrow-derived macrophages or human blood-derived macrophages resident within the in vitro engineered tissues stimulate muscle satellite cell-mediated myogenesis while significantly limiting myofibre apoptosis and degeneration. Moreover, bone-marrow-derived macrophages within engineered tissues implanted in a mouse dorsal window-chamber model augmented blood vessel ingrowth, cell survival, muscle regeneration and contractile function.

Prevalence and predictors of ventriculo-atrial conduction in structurally normal hearts

BACKGROUND

The prevalence of ventriculo-atrial (VA) conduction varies from 20% to 90%, depending on the population studied (Militianu et al., 1997; Inoue et al., 1985; Kazmierczak et al., 1993; Ciemniewski et al., 1990; Hayes and Furman, 1983; Westveer et al., 1984). This wide range is mostly based on studies done in patients with implanted devices or impaired atrioventricular conduction. However, the prevalence of VA conduction in structurally normal heart has not been well documented till date.

OBJECTIVE

To study the prevalence and identify predictors of retrograde conduction via the His-Purkinje system and AV node in structurally normal hearts.

METHODS

We included 54 consecutive adults without structural heart disease who underwent electrophysiological (EP) study for various tachycardias. The basic parameters including PR, AH and HV intervals, atrioventricular Wenckebach point (AVWP) and anterograde effective refractory period (ERP) of atrioventricular node (AVNERP), were measured after ablation. The VA conduction was assessed basally and if absent, after isoprenaline. The VA Wenckebach point (VAWP) and retrograde ERP(VAERP) were recorded in patients showing VA conduction.

RESULTS

The mean age was 37.1±12.6years. Twenty five (46%) of the patients were men. VA conduction was present in 30 (55%) patients at baseline. Of the remaining 24 patients, 18 (34%) showed VA conduction after isoprenaline. Only 6 (11%) patients failed to reveal VA conduction even after adequate response to isoprenaline. Amongst all clinical and EP variables analysed, only the HV interval was shorter (p<0.01) in patients with VA conduction.

CONCLUSION

In structurally normal hearts, VA conduction was present at baseline in 55% of patients. Isoprenaline unmasked VA conduction in an additional 34% of the subjects. The HV interval was longer in patients without VA conduction.

Achilles tendinopathy in club runners

Ultrasound (US) changes within the Achilles tendon are present in asymptomatic Achilles individuals. We assessed the association of US signs with symptoms of Achilles tendinopathy in a study group of club level running athletes and in a control group of athletes training at least 2 times per week. The Achilles tendon was assessed in its entirety on longitudinal US scans, at the musculotendinous junction (MTJ), the calcaneal insertion site, and at a midtendon point. 25 middle distance runners, 19 males and 6 females, aged from 18 to 58, were enrolled in each group. When compared to control athletes, club level runners presented significantly increased tendon thickness (p=0.046) at the musculo-tendinous junction, and increased tendon thickness, with no statistical significance, at the other landmarks points. Although club level runners were significantly more symptomatic and predisposed to develop signs of tendinopathy than control athletes (p=<0.001), ultrasound abnormalities were not significantly associated with local symptoms complained at the US investigation time. Prospective studies on asymptomatic athletes are needed to define the predictive value of US signs of Achilles tendinopathy in the development of symptoms in the long-term.

What animal models have taught us about the treatment of acute stroke and brain protection

Stroke research has progressed in leaps and bounds in the past decades. A driving force is the increasing availability of new research tools in this field (eg, animal stroke models). Animal stroke models have been extensively applied to advance our understanding of the mechanisms of ischemic brain injury and to develop novel therapeutic strategies for reducing brain damage after a stroke. Animal stroke models have been useful in characterizing the molecular cascades of injury processes. These "injury pathways" are also the targets of therapeutic interventions. The major achievements made in the past 2 decades applying animal stroke models include 1) the identification of the mediator role of excitotoxin and oxygen free radicals in ischemic brain injury; 2) the confirmation of apoptosis as a major mechanism of ischemic cell death; 3) the characterization of postischemic gene expression; 4) the delineation of postischemic inflammatory reaction; 5) the application of transgenic mice to confirm the roles of purported mediators in ischemic brain injury; 6) development of novel magnetic resonance imaging sequences for early noninvasive detection of ischemic brain lesions; and, 7) the development of novel therapeutic strategies based on preclinical findings derived from animal stroke models.

Hypoalgesic effect of caffeine in experimental ischemic muscle contraction pain

It has been theorized that adenosine is a leading candidate for the metabolite responsible for ischemic muscle pain. The purpose of this study was to determine the effect of the non-selective adenosine receptor antagonist, caffeine, on ischemic skeletal muscle contraction pain. Seven healthy adult volunteers with no history of pain disorders, systemic disease, or habitual caffeine use, were chosen for the two-session, cross-over, double-blind study. Every subject received either 200 mg of caffeine (NoDoz, Bristol-Myers) or identical placebo 1 hour before each of the two trials. Ischemia of the forearm was achieved by inflation of a blood pressure cuff to 250 mm Hg. Forearm muscle activity was generated by performance of wrist curis using a 5-gram bar at a rate of 40 cycles per minute. Pain was rated at 15-second intervals for 1 minute using a visual analog scale (0 to 10) with verbal descriptors. Significance was determined by univariate and multivariate analyses of variance and covariance including repeated measures. Pain ratings at 15 seconds in the caffeine trial were significantly lower (P < 0.02) than those in the placebo trial. This effect continued at 30 seconds (P < 0.05). However, by 45 seconds, pain in the caffeine trial was not significantly lower (P = 0.4) than that in the placebo trial. These results show that high-dose caffeine exhibits considerable analgesic efficacy in experimental muscle pain, adding support for a role of adenosine in producing ischemic muscle contraction pain.

Clinical profile of 100 cases of liver abscess

One hundred patients with liver abscess were studied for clinical features and complications. They were diagnosed by radiography, ultrasonography, serology and by needle aspiration. A variety of interesting clinical, haematological and ultrasonographic findings were observed. Literature on liver abscess was reviewed and results compared.

Serodiagnosis of amoebic liver abscess by IHA method

Serological test based on IHA (Indirect Haemagglutination Method) was performed in 100 cases of hepatic abscess. The test was 100% sensitive and 94% specific. The cut off point of antibody titer between normal population and patients with invasive amoebiasis was 1:128. Antibody titer in amoebic liver abscess was 1:5242 +/- 2795. A significant (P less than 0.001) correlation was found between total leucocyte count and antibody titer.