1、-Blockers and Cardiac Protection-Blockers and Cardiac Protection-blockers are known as the common drugs to treat CAD, heartfailure, and arthythmia.For many years, -blockers have been regarded as the best drugs toprotect patients with, or at risk for, coronary heart disease, fromperioperative major a

2、dverse cardiac events (MACE).They may reduce the risk of myocardial infarction and cardiac deathin patients with known coronary artery diseaseHowever , In 2008, the POISE study, the largest RCTin perioperative medicine ever undertaken, showed cardiac protection but revealed an increase in all- cause

3、 mortality, disabling strokes, and hypotension when using -blockers.Also -blockers bring some side effects.Our article is to focus on how to use -blockersreasonable and correctly.This is the structure below:Introduction:-blocker best drugs toprotect patients fromMACEthe Applicability of -blockerthe

4、Choices of -blockerSide Effects of -blockerDraw a conclusionWhen Should We Start -Blockers ?the early start :In respect of the early start of -blockade advocated by the current guidelines, only four studies have used this approach, and in two of them, -blockade was not shown to be beneficial .While

5、an early start is logical, new data do not support this.at least 7 days before surgery :In contrast, in two studies from Poldermansgroup,early administration (at least 7 days before surgery) was beneficial.the day of surgery :All the other RCTs started -blockade the day of surgeryWallace and colleag

6、ues collated observation in more than37 000 non-cardiac operationsA protocol for perioperative -blockade wasPatients werefollowed for 1 year.available in their institution but was notmandatorySurvival was best for those who had beenPoorer survival was noted for those noton a -blocker; worst outcome

7、(unsurprisingly) was in those in whom - blockade had been withdrawn.given a -blocker at the time of surgery,followed by those who had been maintainedon -blockade.In the groups of patients in whom -blockade is supported by the current guidelines, latestart, if early start was not possible should not

8、preclude the introduction of -blockadeAnother indication for perioperative -blockade may be toobtund the adrenergic responses to noxious stimuli or toreduce myocardial ischemia.perioperativemyocardial infarction【odds ratio (OR) 0.17 (0.0440.203), seven studies】Analysis of 14reducestudies (n=1298pati

9、ents) -this single-dosetreatmentperioperativemyocardial ischaemia【odds ratio (OR)0.22 (0.135 0.353), eight studies】-Blocker FormulationThere has been controversy in respect of the choice of slow-release metoprolol in POISE.A large observational study by Wallace and colleagues hasshown in 3789 patien

10、ts on continuing -blockade that atenolol was associated with better protection in terms of 30 day and 1 year mortality than metoprolol.Today, bisoprolol is used increasingly frequently and may alsoprove to be more protective than metoprolol.Existing GuidelinesThis was largelybased on the data from a

11、 very large cohort study by Lindenauer and colleagues.Guidelines initiatesthat-blockadeperioperatively shouldbe limited to high-risk patients.2018/10/10the Choices of -blockerSpecies of -blockerThere has been controversy in respect of the choice of slow- release metoprolol in POISE；A large observati

12、onal study by Wallace and colleagueshas shown hat atenolol was associated with better protection in terms of 30 day and 1 yr mortality than metoprolol；Today, bisoprolol is used increasingly frequently and may also prove to be more protective than metoprolol.the Choices of -blockerSpecies of -blocker

13、1.there is good evidence from observational studies andone RCT to support the continuing of chronicblockade during anaesthesia and surgery :( Crandell stated that antihypertensive drugs interfered with haemodynamic adjustments and could cause cardiovascular collapse in patients subjected to the stre

14、ss of anaesthesia and surgery，but Wallace similarly improved outcome )2.However, more recent studies have shown that discontinuing therapy isassociated with significant increases in perioperative morbidity and mortality;the Choices of -blockerTiming of -blockerfour studiesadvocated the early start o

15、f -blockade ；In contrast, in two studies from Poldermans group,early administration (at least 7 days before surgery)was beneficial；All the other RCTs started -blockade the day of surgery.the Choices of -blockerTitration of -blockerhigh doses of metoprolol to be administered shows statisticallyand cl

16、inically significant cardiac protection but revealed anincrease in all-cause mortality, disabling strokes, and hypotension；Single-dose treatment is effective in reducing perioperativeand myocardial ischaemia；myocardial infarctionThese treatments were not associated with significanthypotension or bra

17、dycardia.Side Effects of -blockerHypotension and strokeUsing the BB to maintain a long diastolic period to maximize flow in narrowed coronary arteries. However, there is the risk of severe bradycardia and cardiac failureAs hypotension was found to be an important contributor to perioperative strokes

18、, the suggestion that 100 mm Hg systolic arterial pressure is sufficientThe current recommendation to withhold the BB if there is hypotension seems more logical as even moderately hypertensive patients presenting for surgery may suffer complications if their arterial pressure decreases to and remain

19、s at 100 mm Hg for a prolonged period.Side Effects of -blockerAnaemia and -blockerAs the nadir of haemoglobin decreases, the risk of MACE is much higher in BB than in non-BB patients.BB was associated with an overall reduction in postoperative cardiac events.Patients with low perioperative bleeding, patien