Purpose
To demonstrate a novel method that utilizes retrospective data to develop statistically optimal dosing strategies for medications with sensitive therapeutic windows. We illustrate our approach on intravenous unfractionated heparin, a medication which typically considers only patient weight and is frequently misdosed.
Methods
We identified available clinical features which impact patient response to heparin and extracted 1,511 patients from the multi-parameter intelligent monitoring in intensive care II database which met our inclusion criteria. These were used to develop two multivariate logistic regressions, modeling suband supra-therapeutic activated partial thromboplastin time (aPTT) as a function of clinical features. We combined information from these models to estimate an initial heparin dose that would, on a per-patient basis, maximize the probability of a therapeutic aPTT within 4–8 h of the initial infusion. We tested our model’s ability to classifying therapeutic outcomes on a withheld dataset and compared performance to a weight-alone alternative using volume under surface (VUS) (a multiclass version of AUC).
Results
We observed statistically significant associations between suband supra-therapeutic aPTT, race, ICU type, gender, heparin dose, age and Sequential Organ Failure Assessment scores with mean validation AUC of 0.78 and 0.79 respectively. Our final model improved outcome classification over the weight-alone alternative, with VUS values of 0.48 vs. 0.42.
Conclusions
This work represents an important step in the secondary use of health data in developing models to optimize drug dosing. The next step would be evaluating whether this approach indeed achieves target aPTT more reliably than the current weight-based heparin dosing in a randomized controlled trial.
Aims: Drug-coated balloons (DCB) may avoid stent-associated long-term complications. This trial compared the clinical outcomes of patients with non-ST-elevation myocardial infarction (NSTEMI) treated with either DCB or stents.Methods and results: A total of 210 patients with NSTEMI were enrolled in a randomised, controlled, non-inferiority multicentre trial comparing a paclitaxel iopromide-coated DCB with primary stent treatment. The main inclusion criterion was an identifiable culprit lesion without angiographic evidence of large thrombus. The primary endpoint was target lesion failure (TLF; combined clinical endpoint consisting of cardiac or unknown death, reinfarction, and target lesion revascularisation) after nine months. Secondary endpoints included total major adverse cardiovascular events (MACE) and individual clinical endpoints. Mean age was 67±12 years, 67% were male, 62% had multivessel disease, and 31% were diabetics. One hundred and four patients were randomised to DCB, 106 to stent treatment. In the stent group, 56% of patients were treated with BMS, 44% with current-generation DES. In the DCB group, 85% of patients were treated with DCB only whereas 15% underwent additional stent implantation. During a follow-up of 9.2±0.7 months, DCB treatment was non-inferior to stent treatment with a TLF rate of 3.8% versus 6.6% (intention-to-treat, p=0.53). There was no significant difference between BMS and current-generation DES. The total MACE rate was 6.7% for DCB versus 14.2% for stent treatment (p=0.11), and 5.9% versus 14.4% in the per protocol analysis (p=0.056), respectively.
Conclusions:In patients with NSTEMI, treatment of coronary de novo lesions with DCB was non-inferior to stenting with BMS or DES. These data warrant further investigation of DCB in this setting, in larger trials with DES as comparator (ClinicalTrials.gov Identifier: NCT01489449).
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