A pilot study to assess the utility of five established variables to standardize exercise treadmill test reporting.

BACKGROUND: The prognostic utility of 5 established variables (functional capacity, Duke treadmill score, chronotropic response to exercise, heart rate recovery, and premature ventricular contractions) together after routine exercise treadmill testing (ETT) has not been determined. METHODS: We assessed the combined prognostic ability of 5 established variables for the primary outcome (myocardial infarction [MI], coronary revascularization [CR] or all-cause mortality) and the secondary outcome of unnecessary downstream testing (defined as receipt of further noninvasive imaging without CR, MI, or death) compared with standard methods. Using a retrospective study design, 1857 consecutive patients were enrolled in the year 2014 and followed until December 31, 2015. Optimal discrimination and global fit statistics were assessed from logistic regression models. Classification and regression tree (CART) methodology was used for the final model. RESULTS: The mean [SD] age was 56.0 [12.5]years; median comorbidities (2, IQR 2) with 26% having an equivocal report. Compared to other models, a model with age, sex, and the 5 established variables showed an improvement in discrimination for the primary [c-statistic 0.85 versus (0.69-0.79)] and secondary [c-statistic 0.73 versus (0.65-0.71)] outcomes with substantial improvement in global fit. The final, optimal, 10-fold cross-validated CART model had a c-statistic of 0.78. CONCLUSIONS: The utility of the 5-established variables, based on the current study, resides in its ability to decrease unnecessary downstream testing and improve cardiovascular event prognostication. This is accomplished by removing the subjective interpretation of currently used ETT variables that can lead to an equivocal report.

Association of Age to Mortality and Repeat Revascularization in End-Stage Renal Disease Patients: Implications for Clinicians and Future Health Policies.

BACKGROUND: The clinical effects of age occur over an age continuum, yet age as a primary predictor is often analyzed using arbitrary age cut-points. OBJECTIVE: To assess whether transformation of a continuous variable such as age using a spline function can uncover nonlinear associations between age and cardiovascular outcomes. DESIGN: Observational retrospective cohort study in 1015 Kaiser Permanente Northern California patients with end-stage renal disease after index coronary revascularization. Age, the primary predictor, was modeled by 5 different techniques: 1) dichotomized at 65 years or older; 2) at 80 years or older (as a sensitivity analysis); 3) categorized as younger than 55 years (reference), 55 to 64, 65 to 74, and 75 years or older; 4) linear (every 5 years) variable; and 5) nonlinear by transformation into a cubic spline. Age categories were changed in a sensitivity analysis. MAIN OUTCOME MEASURES: Primary and secondary outcomes were all-cause mortality and repeat revascularization, respectively. RESULTS: Graphical assessment demonstrated that age dichotomized at either 65 years and older or 80 years and older led to loss of information. Categorized age underestimated or overestimated risk at the extremes of age. A sensitivity analysis demonstrated that an arbitrary change in the age category led to a different conclusion. Age modeled linearly adequately represented mortality risk but was suboptimal with repeat revascularization. Only the cubic spline demonstrated the nonlinear association between age and repeat revascularization. CONCLUSION: Employing the continuous variable age as a case study, we have demonstrated that the use of flexible transformations, such as spline functions, can unearth clinically meaningful associations that would not have been possible otherwise. Future research should determine whether incorporation of these methods can improve decision making at a population level.

Atrial fibrillation and cor triatriatum sinister: a case report.

A 29-year-old man presented to our hospital with palpitations, shortness of breath, and orthopnea. After being admitted, he progressed to cardiogenic shock and respiratory failure, which required ventilator support and cardioversion. Subsequent evaluation revealed a fibromuscular membrane across the left atrium, requiring urgent corrective surgery.