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To the Editor: The trials conducted by Obadia et al. (Percutaneous Repair with the MitraClip Device for Severe Functional/Secondary Mitral Regurgitation [MITRA-FR]) 1 and Stone et al. (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation [COAPT]) 2 (both in the Dec. 13 issue) provide contradictory evidence on the efficacy of transcatheter mitral-valve repair for functional mitral regurgitation. Although the reasons for the differences in outcomes are unclear, inconsistencies in the data in the COAPT trial highlight the difficulty of quantifying the severity of functional mitral regurgitation. Patients had a mean (±SD) effective regurgitant orifice . . .

Randomized controlled trials are one of the best ways of quantifying the effectiveness of medical interventions. Therefore, when the authors of a randomized superiority trial report that differences in the primary outcome between the intervention group and the control group are “significant” (i.e., P  ≤ 0.05), we might assume that the intervention has an effect on the outcome. Similarly, when differences between the groups are “not significant,” we might assume that the intervention does not have an effect on the outcome. Nevertheless, both assumptions are frequently incorrect. In this article, we explore the relationship that exists between real treatment effects and declarations of statistical significance based on P values and confidence intervals. We explain why, in some circumstances, the chance an intervention is ineffective when P  ≤ 0.05 exceeds 25% and the chance an intervention is effective when P  > 0.05 exceeds 50%. Over the last decade, there has been increasing interest in Bayesian methods as an alternative to frequentist hypothesis testing. We provide a robust but nontechnical introduction to Bayesian inference and explain why a Bayesian posterior distribution overcomes many of the problems associated with frequentist hypothesis testing. Notwithstanding the current interest in Bayesian methods, frequentist hypothesis testing remains the default method for statistical inference in medical research. Therefore, we propose an interim solution to the “significance problem” based on simplified Bayesian metrics (e.g., Bayes factor, false positive risk) that can be reported along with traditional P values and confidence intervals. We calculate these metrics for four well-known multicentre trials. We provide links to online calculators so readers can easily estimate these metrics for published trials. In this way, we hope decisions on incorporating the results of randomized trials into clinical practice can be enhanced, minimizing the chance that useful treatments are discarded or that ineffective treatments are adopted.

Describes the aetiology, demographics and outcomes of patients with pneumonia undergoing venovenous extracorporeal membrane oxygenation (VV-ECMO) in Aotearoa New Zealand between January 2004 and August 2020. Source: National Library of New Zealand Te Puna Matauranga o Aotearoa, licensed by the Department of Internal Affairs for re-use under the Creative Commons Attribution 3.0 New Zealand Licence.

To the Editor: The recent trial conducted by Kang et al. (Jan. 9 issue) 1 shows a benefit of early surgery in otherwise healthy patients with aortic stenosis. However, we are concerned that the selective performance of exercise testing in the trial patients may have led the investigators to misclassify untested patients who had exertional symptoms as being asymptomatic. Data suggest that exercise testing effectively aids in risk stratification of patients with asymptomatic severe aortic stenosis, 2 and the 2014 American College of Cardiology–American Heart Association (ACC–AHA) guidelines provide a class IIa recommendation for consideration of exercise stress testing in these patients. 3 . . .

To the Editor: Smith et al. (Dec. 4 issue) 1 report that adding mitral-valve repair to coronary-artery bypass grafting (CABG) did not result in a clinically meaningful benefit. These results could justify changes in recent guidelines. 2 , 3 However, important data have not been provided, such as the site and number of previous myocardial infarctions, the mean interval between myocardial infarction and surgery, the type of atrial fibrillation at baseline, and the use of antithrombotic therapies. There was probably more frequent use of anticoagulants in the group undergoing CABG alone. Some measurements of valve-tethering forces, which have been shown to predict unfavorable . . .

Peter Alison, David Sidebotham Over the last decade there has been a large increase in the use of catheter-based, percutaneous coronary interventions (PCIs)--initially with balloon angioplasty, but latterly with bare-metal (BMS) or drug-eluting stents (DES)--for treating coronary artery disease. Of the population screened for trial inclusion, only about 5% were ultimately randomised, of whom only 35% had three-vessel disease, none had left main stem disease, only 40% had proximal LAD disease, and patients with poor left ventricular function were excluded. [...]the patients enrolled in these trials were highly selected, and did not include those patients most likely to benefit from CABG surgery. In the Argentine Randomised Study: Coronary Angioplasty versus Coronary Bypass Surgery in Multi-Vessel Disease (ERACI II) trial, 60% of patients had either three-vessel or left main stem coronary artery disease, but patients with poor left ventricular function were excluded.5 There were significantly fewer major adverse cardiac events (including death, myocardial infarction, re-hospitalisation; MACE) at 30 days in patients randomised to PCI compared to patients randomised to CABG surgery (3.65% vs 12.3%, p=0.002).

The term extracorporeal life support (ECLS) refers to devices used to support the heart and lungs and includes extracorporeal membrane oxygenation and ventricular assist devices (VADs). These devices may be used as a bridge to transplantation or for cardiorespiratory support following transplantation. The primary focus of this chapter is the use of ECLS after thoracic transplantation.

Several chemotherapeutic agents, including newer drugs, can have toxic cardiac effects. In this month's Case Study, To and colleagues present their patient who had capecitabine-induced cardiogenic shock. They examine the best course of action for this serious complication of chemotherapy. Background A 52-year-old woman underwent successful resection of stage IIB primary mucinous adenocarcinoma of the appendix and was started on capecitabine chemotherapy. Five days into the first course, after initially experiencing diarrhea, nausea, vomiting and a transient episode of retrosternal chest pain radiating to the left scapula, she presented to the emergency department with cardiogenic shock. Investigations Electrocardiography, transthoracic echocardiography, laboratory investigation of cardiac biomarkers, coronary angiography and endomyocardial biopsy. Diagnosis Capecitabine-induced cardiogenic shock. Management Supportive treatment with dopamine, milrinone, norepinephrine (noradrenaline) and levosimendan.