Beta-blockers have the greatest cardiovascular impact in patients with reduced heart function/heart failure and in reducing the peri-operative risk of atrial fibrillation. In patients without these high-risk features treated with coronary artery bypass graft (CABG) surgery, their continued long-term role is unclear.
This is an open-label, non-inferiority, randomized comparison of beta-blocker continuation versus de-prescription at the 6-8 week follow-up following isolated and uncomplicated CABG at Royal University Hospital, Saskatoon. Patients treated with isolated CABG (without valve repair/replacement) and discharged on a beta-blocker are eligible for recruitment if they have preserved systolic function (EF ≥45%) and no history of heart failure, atrial fibrillation/flutter, or an alternate compelling indication for beta-blocker therapy. After obtaining informed consent, eligible patients are randomly assigned at 6-8 weeks to one of the two treatment groups: continued beta-blocker therapy per their usual clinical care OR beta-blocker de-prescription as per the study protocol. The primary objective of this study is to demonstrate recruitment feasibility for beta-blocker de-prescription 6-8 weeks following uncomplicated CABG. Exploratory outcomes include the composite of all-cause mortality, myocardial infarction, stroke, arrhythmia, and cardiovascular-related hospitalization (congestive heart failure, recurrent ischemia, arrhythmia \[supraventricular including atrial fibrillation, and ventricular\], syncope or need for pacemaker) over a 3-year follow up duration. Other exploratory outcomes will include a change in the patient reported quality of life using the Short Form (SF) 36 and Euro Qol (EQ) 5D questionnaires and angina score using the Seattle Angina Questionnaire (SAQ).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
200
Participants will be de-prescribed for beta-blocker therapy. De-prescription will be performed as follows: * Half of pre-randomization dose for the first 3 days, then * Half of the above dose for the next 3 days, then discontinue
Royal University Hospital
Saskatoon, Saskatchewan, Canada
RECRUITINGRate of all-cause mortality
All-cause death includes death resulting from both cardiovascular and non-cardiovascular causes.
Time frame: 3 years
Rate of spontaneous myocardial infarction
All spontaneous (type 1) myocardial infarctions as per the Universal MI definition. Typical rise or fall of biochemical markers of myocardial necrosis to greater than twice the upper limit of normal (ULN). If markers were already elevated, and have not reached their peak then further elevation of a marker ≥50% of a previous value and \>2X ULN is required. If biomarkers are stable or decreasing then a re-elevation of ≥ 20% and \> 2X ULN is required. All also require meeting at least one of the following criteria: * Ischemic symptoms * Development of new pathological Q waves (distinct from index STEMI) * ECG changes of new ischemia or * Pathological evidence of MI
Time frame: 3 Years
Rate of stroke
On the basis of CT or MRI imaging or autopsy, stroke is classified as: * Ischemic stroke (including hemorrhagic transformation of ischemic stroke) * Hemorrhagic stroke (including intracerebral / intraparenchymal hemorrhage and subarachnoid hemorrhage) * Undetermined stroke (no imaging or autopsy available)
Time frame: 3 Years
Rate of hospitalizations for heart failure
Physician decision to treat heart failure with intravenous furosemide, if already on oral diuretics (for an alternate indication other than prior congestive heart failure (CHF\*), a 50% dose increase) with New York Heart Association class III or IV symptoms plus at least one of the following: * Presence of pulmonary edema or pulmonary vascular congestion on chest radiograph thought to be due to heart failure * Rales reaching above the lower 1/3 of the lung fields thought to be due to heart failure or * Pulmonary capillary wedge pressure (PCWP) or left ventricular end diastolic pressure (LVEDP) \>18 mm Hg * Patients with a prior history of heart failure are not eligible for randomization.
Time frame: 3 Years
Rate of cardiac arrhythmia
Supraventricular (excluding atrial fibrillation) * Includes all forms of Supraventricular tachycardia (SVT) such as atrioventricular reentry tachycardia (AVRT), atrioventricular node reentry tachycardia (AVNRT), atrial tachycardia * Atrial fibrillation Any new finding of clinical atrial fibrillation lasting greater than 30 seconds plus at least one of the following: * ECG * Rhythm strip * If ECG document or Holter report is unavailable, clear physician diagnosis Ventricular Non-sustained or sustained ventricular tachycardia or ventricular fibrillation
Time frame: 3 Years
Rate of syncope or need for permanent pacemaker
Syncope suspicious for cardiac etiology requiring either hospitalization for ≥ 24 hours or needing an implantable monitoring device (such as loop recorder) or permanent pacemaker
Time frame: 3 Years
Rate of recurrent myocardial ischemia
Hospitalization or stay in the emergency department for ≥ 24 hours for myocardial ischemia or requiring unplanned revascularization
Time frame: 3 Years
Change in patient reported quality of life (QoL) using Euro Qol (EQ) 5D questionnaire
Change in scores will be used to describe differences in the quality of life between the two study arms (Continuation Vs De-prescription). The EQ-5D is a patient self-reported questionnaire scored from 0 (being the worst health state imaginable meaning worse outcome) to 100 (being the best health state imaginable meaning better outcome).
Time frame: 3 years
Change in patient reported quality of life using Short Form (SF) 36 questionnaire
Change in scores will be used to describe differences in the quality of life between the two study arms (Continuation Vs De-prescription). The SF-36 consists of eight scaled scores. Each scale is directly transformed into a 0-100 scale on the assumption that each question carries equal weight. The lower the score the more disability (meaning worse outcome). The higher the score the less disability (meaning better outcome) i.e., a score of zero is equivalent to maximum disability and a score of 100 is equivalent to no disability.
Time frame: 3 years
Change in the patient reported angina score using the Seattle Angina Questionnaire (SAQ)
The Seattle Angina Questionnaire is the most sensitive, specific, and responsive health-related quality of life instrument for coronary artery disease. The SAQ is a self-administered, disease-specific measure for patients with CAD that is valid, reproducible, and sensitive to clinical change. Each scale is transformed to a score of 0 to 100, where higher scores indicate better function (eg, less physical limitation, less angina, and better quality of life).
Time frame: 3 years
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