Utility of Restricted Mean Survival Time Analysis for Heart Failure Clinical Trial Evaluation and Interpretation.

OBJECTIVES: This study sought to demonstrate the statistical and utilitarian properties of restricted mean survival time (RMST) and restricted mean time lost (RMTL) for assessing treatments for heart failure (HF) with reduced ejection fraction. BACKGROUND: Although the hazard ratio (HR) is the most commonly used measure to quantify treatment effects in HF clinical trials, HRs may be difficult to interpret and require the proportional hazards assumption to be valid. RMST and RMTL are intuitive summaries of groupwise survival that measure treatment effects without model assumptions. METHODS: Patient time-to-event data were reconstructed from published landmark HF clinical trial Kaplan-Meier curves. We estimated RMST differences (ΔRMSTs) and RMTL ratios between treatment groups for primary and secondary outcomes, and compared test statistics and effect sizes with proportional hazards models. We fit Weibull estimations to extrapolate trial data to 5 years of treatment. RESULTS: Using RMSTs and RMTLs yielded similar statistical conclusions as HR analysis for a compendium of 16 HF clinical trials including 48,581 patients. RMTL ratios approximated HRs for each trial, but ΔRMSTs provided absolute effect sizes unavailable with HRs. For instance, spironolactone added 2.2 months of life over 34 months of treatment, and dapagliflozin added 0.3 months of life over 24 months of treatment. When normalized to 5-years follow-up with Weibull estimation, spironolactone and dapagliflozin added 6.0 months and 1.8 months of life for patients, respectively. CONCLUSIONS: Statistically, RMST and RMTL perform similarly to proportional hazards modeling but may help patients by providing clinically relevant intuitive estimates of treatment effects without prohibitive assumptions.

A new score based on the PEGASUS-TIMI 54 criteria for risk stratification of patients with acute myocardial infarction.

BACKGROUND: Acute myocardial infarction (AMI) patients are at increased risk of death and recurrent ischemic events. We aimed to elaborate a risk score, based on the PEGASUS-TIMI 54 criteria, to predict mortality and non-fatal AMI in AMI patients. METHODS: We retrospectively analyzed two prospectively collected AMI cohorts. We calculated a cut-off for the developed score and investigated its 1-year prognostic power in the derivation cohort (n = 1257). We externally validated our score in 913 AMI patients with a longer follow-up. RESULTS: In the derivation cohort, the area under the curve of the score for the primary endpoint (1-year death and non-fatal AMI) was 0.70 (95% CI 0.65-0.76; P < 0.0001) and a cut-off of 6 was identified. The primary endpoint incidence in patients with a score above and below the cut-off was 12% and 3% (P < 0.001) in the derivation cohort and 16% and 6% in the validation cohort (P < 0.001). At multivariate analysis, the HR for the primary endpoint associated with a score ≥ 6 was 4.45 (P < 0.0001) in the derivation cohort and 2.86 (P < 0.0001) in the validation cohort. One-year major bleeding rate was low (<0.2% overall) and similar between risk groups. The prognostic performance of the score cut-off persisted beyond the first year after AMI in the validation cohort, maintaining a similar risk for death and non-fatal AMI (HR 3) at every following year. CONCLUSIONS: Our score, based on the PEGASUS-TIMI 54 criteria, may identify AMI patients at high risk of recurrent ischemic events, who might benefit from thorough preventive strategies.

Blood pressure control in older patients with carotid artery stenosis.

Stroke is the second largest cause of European cardiovascular and total mortality, largely due to atherosclerotic carotid artery narrowing or thromboembolism consequent to internal carotid artery stenosis. Current therapeutic indications suggest lifestyle interventions (smoking cessation, healthy diet and physical activity), adequate control of LDL-cholesterol and glycemic balance. It is nonetheless established that the most important factors in preventing stroke are antiplatelet therapy and blood pressure regulation. In fact, many physiological parameters, including age, drugs' effects and especially systemic blood pressure, can be involved in maintaining cerebral blood flow through compensation for impairment of flow within carotid arteries. Many studies demonstrate the benefits of blood pressure lowering in terms of prevention of stroke, but there are conflicting data about a specific pressure target to achieve, with some evidence in favor of "the lower the better" idea, while other identifying a too low systolic blood pressure as a cause of cerebral ischemia worsening, especially in symptomatic patients. In summary, the available data suggest the need of a tailored blood pressure treatment without inflexible targets, according to the assessment of the cardiovascular risk of each patient, the benefits of an intensive antihypertensive therapy and the comorbidities-related response to the treatment.

Impact of cuff positioning on blood pressure measurement accuracy: may a specially designed cuff make a difference?

During blood pressure (BP) measurement, the recommended positioning of the cuff bladder center is directly above the brachial artery. We investigated the relevance of incorrect cuff positioning during (1) auscultatory measurement with an appropriate or improperly small cuff and (2) oscillometric measurement with a wide-range cuff designed to guarantee accurate measurements regardless of position. In subjects with wide BP and arm circumference ranges, (1) auscultatory BP was repeatedly measured with a properly positioned cuff (reference) and, simultaneously, with an identical cuff placed on the other arm in either a correct or an incorrect position (test). The measurements were performed with a properly sized (N=57) or an improperly small cuff (N=33). (2) Auscultatory measurements obtained with a properly positioned and sized cuff were compared with oscillometric measurements obtained with a specially designed wide-range cuff (Omron IntelliWrap) placed on the contralateral arm either in a correct or an incorrect position. Auscultatory BP measures were unaffected by incorrect positioning of a properly sized cuff, whereas with undercuffing, BP was overestimated with the cuff displaced by 90° laterally (systolic/diastolic BP differences: 4.9±4.6/4.0±4.6 mm Hg, P<0.01) or by 180° (3.9±5.4/4.2±5.1 mm Hg, P<0.01) in relation to the correct position. Incorrect placement of the oscillometric cuff had no significant effect on the accuracy of the measurements (difference with correct position <1.5 mm Hg). Incorrect cuff positioning introduces a systematic overestimation of auscultatory BP when the cuff is too small in relation to arm circumference but not when it is correctly sized. No systematic error was observed with oscillometric measurements obtained with a specially designed wide-range cuff.