Perioperative beta-blockade and late cardiac outcomes: A complementary hypothesis

Protecting the Heart with Cardiac Medication in Patients with Left Ventricular Dysfunction Undergoing Major Noncardiac Vascular Surgery

Patients with left ventricular dysfunction who are undergoing major noncardiac vascular surgery are at increased risk of adverse postoperative events. We sought to evaluate whether perioperative medication use, including angiotensin-converting enzyme (ACE) inhibitors,b-blockers, statins, and aspirin, was associated with a reduced incidence of postoperative in-hospital mortality in these high-risk patients. The study enrolled 511 patients with left ventricular dysfunction (left ventricular ejection fraction <30%) who were undergoing major noncardiac vascular surgery. Cardiac risk factors and medication use were noted before surgery. Preoperative dobutamine stress echocardiography (DSE) was performed to identify patients with stress-induced myocardial ischemia. The end point was postoperative in-hospital mortality. Univariate and multivariate logistic regression analyses were performed to evaluate the relation between perioperative medication use and mortality. The mean age of the study population was 64 ± 11 years, and 75% were men. Perioperative use of ACE inhibitors, b-blockers, statins, and aspirin was recorded in 215 (48%), 139 (27%), 107 (21%), and 125 patients (24%), respectively. Stress-induced myocardial ischemia occurred in 82 patients (16%). Sixty-four patients (13%) died. Perioperative use of ACE inhibitors (odds ratio [OR], 0.33; 95% confidence interval [CI], 0.12-0.91), b-blockers (OR, 0.03; 95% CI, 0.01-0.26), statins (OR, 0.06; 95% CI, 0.01-0.53), and aspirin (OR, 0.13; 95% CI, 0.03-0.55), was significantly associated with a reduced incidence of mortality, after adjusting for cardiac risk factors and DSE results. In conclusion, the present study showed that the perioperative use of ACE inhibitors,b-blockers, statins, and aspirin is independently associated with a reduced incidence of in-hospital mortality in patients with left ventricular dysfunction who are undergoing major noncardiac vascular surgery.

Perioperative cardioprotection

Although anaesthesia itself is now very safe, perioperative cardiac complications during non-cardiovascular surgery are a major cause of morbidity and mortality, because of the increasingly high underlying prevalence of cardiovascular disease. Fortunately, although there is no "magic bullet", pharmacological intervention can reduce the risk. In particular, current evidence strongly supports the use of aspirin and statins. Beta blockers may also be beneficial in higher risk groups but need to be titrated to effect, and their use requires careful consideration because of adverse effects in these patients.

Cardioprotective effects of perioperative β-blockade in vascular surgery patients: fact or fiction?

PURPOSE OF REVIEW

Perioperative β-blockade remains a subject of debate. In this review, recent literature and current guidelines for perioperative β-blockade in vascular surgery patients are discussed.

RECENT FINDINGS

Available evidence suggests that perioperative β-blockade may be beneficial in reducing cardiac events. However, in a recent large study, the incidences of stroke and mortality were increased in patients on perioperative β-blockers. Large systematic reviews failed to demonstrate a net beneficial effect of perioperative β-blockers. The 2009 American and the European guidelines for perioperative β-blockade in vascular surgery disagree on the available evidence but do recommend β-blockade for several indications. Most recent, Wallace and colleagues published a large-sized retrospective study, reporting a beneficial effect of the adoption of a protocol for perioperative β-blockade.

SUMMARY

Perioperative β-blockade reduces cardiac events, but at the expense of increased risk for mortality and stroke. The guidelines seem to be eager to follow positive outcome studies, without considering the effects of β-blockade on other organ systems. Perhaps the main reason for the reported cardioprotective effects of perioperative β-blocker therapy should be sought in failing preoperative β-blocker prophylaxis (irrespective of surgery).

ß-Blockers reduce mortality in patients undergoing high-risk non-cardiac surgery

BACKGROUND

ß-Adrenergic receptor antagonists (beta-blockers) are frequently used with the aim of reducing perioperative myocardial ischemia and infarction. However, randomized clinical trials specifically designed to evaluate the effects of beta-blockers on mortality in patients undergoing non-cardiac surgery have yielded conflicting results.

OBJECTIVE

This study aimed to examine the effect of perioperative ß-blockers on total and cardiovascular mortality in patients undergoing non-cardiac surgery.

METHODS

We conducted a meta-analysis of randomized clinical trials that examined the effects of ß-blockers versus placebo on cardiovascular and all-cause mortality in patients undergoing non-cardiac surgery. We extracted data from articles published before 30 November 2009 in peer-reviewed journals indexed in MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE and CINAHL. Data extraction was carried out independently by two reviewers on the basis of an intent-to-treat approach, and inconsistencies were discussed and resolved in conference. The present meta-analysis was undertaken according to the Quality of Reporting of Meta-analyses (QUORUM) statement.

RESULTS

A total of 2148 records were screened, from which we identified 74 randomized controlled trials for non-cardiac surgery. After excluding 49 studies that did not report the clinical outcome of interest or were subanalyses or presented duplicate data, the final search left 25 clinical trials. Treatment with ß-blockers had no significant effect on all-cause mortality (odds ratio [OR] 1.15; 95% confidence interval [CI] 0.92, 1.43; p = 0.2717) or cardiovascular mortality (OR 1.13; 95% CI 0.85, 1.51; p = 0.5855). However, surgical risk category markedly differed across the studies. According to Joint American College of Cardiology and American Heart Association guidelines for perioperative assessment of patients having non-cardiac surgery, five trials evaluated the effect of ß-blockers in patients treated with emergency and vascular surgery (high-risk category) whereas 15 and five trials evaluated the effect of ß-blockers in intermediate low and intermediate high surgical risk categories, respectively. Subgroup analyses showed that the surgical risk category and dose titration of ß-blockers to target heart rate affected the estimate of the effect of ß-blockers for all-cause and cardiovascular mortality. ß-Blockers reduced total mortality by 61% more in patients who underwent high-risk surgery than in those who underwent intermediate high- or intermediate low-risk surgery. When cardiovascular mortality was assessed, the benefit of ß-blockers was 74% greater in trials that titrated ßblockers to heart rate than in trials that did not, although formal statistical significance was not achieved.

CONCLUSIONS

These data suggest that ß-blockers may be useful for reducing mortality in patients who undergo high-risk non-cardiac surgery.

[Perioperative beta-receptor blockade. For and against]

Results from recent studies have questioned the application of beta-receptor blockers for reduction of morbidity and mortality during the perioperative period. This holds true especially for patients with no or only low cardiac risk. Although beta-receptor blockade was a form of standard therapy at the end of the 1990s, data today show no clear evidence for such a therapy not even in patients at risk for cardiac events. At least in patients with low risk the initiation of beta-receptor blockade during the perioperative period might lead to side-effects, thereby increasing morbidity and mortality.

β-blockers and risk of all-cause mortality in non-cardiac surgery

Myocardial ischemia is a frequent complication in patients undergoing non-cardiac surgery and β-blockers may exert a protective effect. The main benefit of β-blockers in perioperative cardiovascular morbidity and mortality is believed to be linked to specific effects on myocardial oxygen supply and demand. β-blockers may exert anti-inflammatory and anti-arrhythmic effects. Randomized clinical trials which evaluated the effects of β-blockers on all-cause mortality in patients undergoing non-cardiac surgery have yielded conflicting results. In 9 trials, 10,544 patients with non-cardiac surgery were randomized to β-blockers (n = 5274) or placebo (n = 5270) and there were a total of 304 deaths. Patients randomized to β-blockers group showed a 19% increased risk of all-cause mortality (odds ratio [OR] 1.19, 95% confidence interval (CI) 0.95-1.50; p = 0.135). However, trials included in the meta-analysis differed in several aspects, and a significant degree of heterogeneity (I 2 = 46.5%) was noted. A recent analysis showed that the surgical risk category had a substantial influence on the overall estimate of the effect of β-blockers. Compared with patients in the intermediate-high-surgical-risk category, those in the high-risk category showed a 73% reduction in the risk of total mortality with β-blockers compared with placebo (OR 0.27, 95% CI 0.10-0.71, p = 0.016). These data suggest that perioperative β-blockers confer a benefit which is mostly limited to patients undergoing high-risk surgery.

Use of a nurse-led intervention to optimize beta-blockade for reducing cardiac events after major noncardiac surgery

BACKGROUND

Although guidelines recommend the use of beta-adrenoceptor blocking drugs to reduce cardiac events (CEs) after major noncardiac surgery, trial results have varied between showing benefit, ineffectiveness, and harm. We sought whether optimizing beta-blockade (BB) delivery could make them more effective.

METHODS

Intermediate risk patients undergoing major noncardiac surgery (n = 400) were randomized to 2 strategies of BB therapy: universal BB (UBB; n = 197) comprising an algorithm-based, nurse-led strategy to optimize dosing and adherence to bisoprolol titration over > or =1 week preoperatively versus usual care (UC; n = 203), whereby BB are continued in those already taking them or prescribed for patients identified as high risk based on ischemia (new or inducible wall motion abnormalities) at dobutamine echocardiography (DbE). Daily electrocardiogram and troponin levels were obtained on 3 postoperative days. The primary end point was a major CE (cardiac death or myocardial infarction) within 30 days.

RESULTS

There were 25 major CEs (6.3%), occurring in 13 (6.6%) of 197 UBB and 12 (5.9%) of 203 UC patients (OR 1.12, 95% CI 0.52-2.39). Independent predictors of CEs were baseline systolic blood pressure (beta 1.02, P = .005) and postoperative hypotension (beta 1.02, P = .03) but not treatment strategy. Those randomized to UBB had significantly better heart rate control perioperatively, at the cost of bradycardia and hypotension. The negative predictive value of DbE in this study was 95%.

CONCLUSIONS

These data confirm a persistent CE rate after major noncardiac surgery despite nurse-led dose titration of bisoprolol. Cardiac events were equivalent to a UC strategy based on DbE results.

Perioperative beta-blockers for major noncardiac surgery: Primum Non Nocere

Recent studies have called into question the benefit of perioperative beta blockade, especially in patients at low to moderate risk of cardiac events. Once considered standard of care, the role of beta-blocker therapy now lies mired in conflicting data that are difficult to apply to the at-risk patient. We provide an overview of the evolution of perioperative beta blockade, beginning with the physiology of the adrenergic system, with emphasis on the biologic rationale for the perioperative implementation of beta-blockers. Although initial studies were small in size and statistically limited, early data showed cardiac benefit with the use of perioperative beta-blockers. However, larger, more recent studies now suggest a lack of benefit and potential harm from this practice. This paradigm holds true especially in those at low-to-moderate cardiovascular risk profiles. Potential explanations for these paradoxical results are discussed, stressing the key differences between earlier and current studies that may explain these divergent outcomes. We conclude by commenting on performance measures as they relate to perioperative beta-blockers and make recommendations for the continued safe implementation of this practice.

Prognostic value of hypotensive blood pressure response during single-stage exercise test on long-term outcome in patients with known or suspected peripheral arterial disease

OBJECTIVE

A decline in systolic blood pressure during exercise is thought to be a sign of severe coronary artery disease. However, no studies have yet examined this effect in patients with known or suspected peripheral arterial disease. Therefore, we investigated the prognostic value of hypotensive blood pressure response after single-stage exercise test on long-term mortality, major adverse cerebrovascular and cardiac events (MACCE) and the effects of statin, beta-blocker and aspirin use in patients with known or suspected peripheral arterial disease.

METHODS

A total of 2022 patients were enrolled in an observational study with a mean follow-up of 5 years. Hypotensive blood pressure response, 4.6% of the total population, was defined as a drop in exercise systolic blood pressure below resting systolic blood pressure.

RESULTS

Our study showed that hypotensive blood pressure response was associated with an increased risk of all-cause mortality [hazard ratio (HR): 1.74, 95% confidence interval (CI): 1.10-2.73] and MACCE (HR: 1.85, 95% CI: 1.14-3.00), independent of other clinical variables. Additionally, after adjustments for clinical risk factors and propensity score, baseline statin use was associated with a reduced risk of all-cause mortality (HR: 0.60, 95% CI: 0.44-0.80). Besides, statin and aspirin use were both also associated with a reduced risk of MACCE (HR: 0.65, 95% CI: 0.47-0.89 and HR: 0.69, 95% CI: 0.53-0.88, respectively).

CONCLUSION

Hypotensive blood pressure response after single-stage treadmill exercise tests in patients with known or suspected peripheral arterial disease was associated with a higher risk for all-cause long-term mortality and MACCE, which might be reduced by statin and aspirin use.

Perioperative beta blockers in patients having non-cardiac surgery: a meta-analysis

BACKGROUND

American College of Cardiology and American Heart Association (ACC/AHA) guidelines on perioperative assessment recommend perioperative beta blockers for non-cardiac surgery, although results of some clinical trials seem not to support this recommendation. We aimed to critically review the evidence to assess the use of perioperative beta blockers in patients having non-cardiac surgery.

METHODS

We searched Pubmed and Embase for randomised controlled trials investigating the use of beta blockers in non-cardiac surgery. We extracted data for 30-day all-cause mortality, cardiovascular mortality, non-fatal myocardial infarction, non-fatal stroke, heart failure, and myocardial ischaemia, safety outcomes of perioperative bradycardia, hypotension, and bronchospasm.

FINDINGS

33 trials included 12 306 patients. beta blockers were not associated with any significant reduction in the risk of all-cause mortality, cardiovascular mortality, or heart failure, but were associated with a decrease (odds ratio [OR] 0.65, 95% CI 0.54-0.79) in non-fatal myocardial infarction (number needed to treat [NNT] 63) and decrease (OR 0.36, 0.26-0.50) in myocardial ischaemia (NNT 16) at the expense of an increase (OR 2.01, 1.27-3.68) in non-fatal strokes (number needed to harm [NNH] 293). The beneficial effects were driven mainly by trials with high risk of bias. For the safety outcomes, beta blockers were associated with a high risk of perioperative bradycardia requiring treatment (NNH 22), and perioperative hypotension requiring treatment (NNH 17). We recorded no increased risk of bronchospasm.

INTERPRETATION

Evidence does not support the use of beta-blocker therapy for the prevention of perioperative clinical outcomes in patients having non-cardiac surgery. The ACC/AHA guidelines committee should soften their advocacy for this intervention until conclusive evidence is available.

Usefulness of hypertensive blood pressure response during a single-stage exercise test to predict long-term outcome in patients with peripheral arterial disease

The prognostic value of a hypertensive blood pressure (BP) response is still unclear. Therefore, the prognostic value of a hypertensive BP response in patients during single-stage exercise testing for peripheral arterial disease (PAD) on long-term mortality and major adverse cerebrovascular and cardiac events (MACCEs) was investigated. In addition, effects of statin, beta-blocker, and aspirin use in patients with known or suspected PAD were studied. A total of 2,109 patients were enrolled in an observational prospective study from 1993 to 2005. Hypertensive BP response was defined as an increase in systolic BP > or = 55 mm Hg (95(th) percentile within our population) after a single-stage treadmill exercise test. The outcome was obtained by using the civil registries, and a questionnaire about cardiac events was sent to all survivals. Hypertensive BP response was associated with increased risk of long-term mortality (hazard ratio [HR] 1.42, 95% confidence interval [CI] 1.12 to 1.80) and MACCEs (HR 1.47, 95% CI 1.09 to 1.97). After adjustments for clinical risk factors and propensity score, baseline statin use was associated with reduced risk of long-term mortality (HR 0.59, 95% CI 0.44 to 0.79), and statin, beta-blocker, and aspirin use were associated with reduced risk of MACCEs (HR 0.59, 95% CI 0.43 to 0.81; HR 0.75, 95% CI 0.60 to 0.95; HR 0.73, 95% CI, 0.57 to 0.92, respectively). In conclusion, hypertensive BP response at exercise in patients with known or suspected PAD is an important independent risk factor for all-cause long-term mortality and MACCEs, whereas statin, beta-blocker, and aspirin use were associated with an improved outcome.

Beta-blockers and statins are individually associated with reduced mortality in patients undergoing noncardiac, nonvascular surgery

BACKGROUND

Patients undergoing noncardiac, nonvascular surgery are at risk for perioperative mortality owing to underlying (a)symptomatic coronary artery disease. We hypothesized that beta-blocker and statin use are associated with reduced perioperative mortality.

METHODS

We performed a case-control study in 75 581 patients who underwent 108 593 noncardiac, nonvascular surgery at the Erasmus Medical Center between 1991 and 2001. Cases were the 989 patients who died during hospital stay after surgery. From the remaining patients, 1879 matched controls (age, sex, calendar year and type of surgery) were selected. Information was then obtained regarding the use of beta-blockers and statins and the presence of cardiac risk factors.

RESULTS

The median age of the study population was 63 years; 61% were men. beta-blockers were less often used in cases than in controls (6.2 vs. 8.2%; P=0.05), as were statins (2.4 vs. 5.5%; P<0.001). After adjustment for the propensity of beta-blocker use and cardiovascular risk factors, beta-blockers were associated with a 59% mortality reduction (odds ratio 0.41; 95% confidence interval 0.28-0.59). Statins were associated with a 60% mortality reduction (adjusted odds ratio 0.40; 95% confidence interval 0.24-0.68). A significant interaction between beta-blockers and statins was observed (P<0.001). In the presence of each other, statins and beta-blockers were not associated with reduced mortality (adjusted odds ratio 2.0 and 95% confidence interval 0.74-5.7 and adjusted odds ratio 1.3 and 95% confidence interval 0.52-3.2). It should be, however, noted that only nine cases and 29 controls used both agents simultaneously.

CONCLUSION

This case-control study provides evidence that beta-blockers and statins are individually associated with a reduction of perioperative mortality in patients undergoing noncardiac, nonvascular surgery.

High-Dose -Blockers and Tight Heart Rate Control Reduce Myocardial Ischemia and Troponin T Release in Vascular Surgery Patients

BACKGROUND

Adverse perioperative cardiac events occur frequently despite the use of beta (beta)-blockers. We examined whether higher doses of beta-blockers and tight heart rate control were associated with reduced perioperative myocardial ischemia and troponin T release and improved long-term outcome.

METHODS AND RESULTS

In an observational cohort study, 272 vascular surgery patients were preoperatively screened for cardiac risk factors and beta-blocker dose. Beta-blocker dose was converted to a percentage of maximum recommended therapeutic dose. Heart rate and ischemic episodes were recorded by continuous 12-lead electrocardiography, starting 1 day before to 2 days after surgery. Serial troponin T levels were measured after surgery. All-cause mortality was noted during follow-up. Myocardial ischemia was detected in 85 of 272 (31%) patients and troponin T release in 44 of 272 (16.2%). Long-term mortality occurred in 66 of 272 (24.2%) patients. In multivariate analysis, higher beta-blocker doses (per 10% increase) were significantly associated with a lower incidence of myocardial ischemia (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.51 to 0.75), troponin T release (HR, 0.63; 95% CI, 0.49 to 0.80), and long-term mortality (HR, 0.86; 95% CI, 0.76 to 0.97). Higher heart rates during electrocardiographic monitoring (per 10-bpm increase) were significantly associated with an increased incidence of myocardial ischemia (HR, 2.49; 95% CI, 1.79 to 3.48), troponin T release (HR, 1.53; 95% CI, 1.16 to 2.03), and long-term mortality (HR, 1.42; 95% CI, 1.14 to 1.76).

CONCLUSIONS

This study showed that higher doses of beta-blockers and tight heart rate control are associated with reduced perioperative myocardial ischemia and troponin T release and improved long-term outcome in vascular surgery patients.

β-Blockers Improve In-hospital and Long-term Survival in Patients with Severe Left Ventricular Dysfunction Undergoing Major Vascular Surgery

OBJECTIVES

To study whether beta-blockers reduce in-hospital and long-term mortality in patients with severe left ventricular dysfunction (LVD) undergoing major vascular surgery.

DESIGN

Observational cohort study.

MATERIALS

Five hundred and eleven patients with severe LVD (ejection fraction<30%) undergoing major non-cardiac vascular surgery.

METHODS

In all patients, cardiac risk factors, medication (including beta-blockers), and dobutamine stress echocardiography (DSE) results were noted prior to surgery. DSE was evaluated for rest and stress-induced new wall motion abnormalities. Endpoint was in-hospital and long-term mortality. Propensity scores for beta-blockers were calculated and regression models were used to analyse the relation between beta-blockers and mortality.

RESULTS

Mean age was 64+/-11 years and 383 patients (75%) were male. 139 patients (27%) used beta-blockers. Stress-induced ischemia occurred in 82 patients (16%). Median follow-up was 7 years (interquartile range: 3-10). In-hospital and long-term mortality was observed in 64 (13%) and 171 (33%) patients, respectively. After adjusting for clinical variables, DSE results and propensity scores, beta-blockers were significantly associated with reduced in-hospital and long-term mortality (OR: 0.18, 95% CI: 0.04-0.74 and HR: 0.38, 95% CI: 0.22-0.65, respectively).

CONCLUSION

In patients with severe LVD undergoing major vascular surgery, the use of beta-blockers is associated with a reduced incidence of in-hospital and long-term postoperative mortality.

Cardioprotective Medication Is Associated With Improved Survival in Patients With Peripheral Arterial Disease

OBJECTIVES

We sought to investigate the effect of cardiac medication on long-term mortality in patients with peripheral arterial disease (PAD).

BACKGROUND

Peripheral arterial disease is associated with increased cardiovascular morbidity and mortality. Treatment guidelines recommend aggressive management of risk factors and lifestyle modifications. However, the potential benefit of cardiac medication in patients with PAD remains ill defined.

METHODS

In this prospective observational cohort study, 2,420 consecutive patients (age, 64 +/- 11 years, 72% men) with PAD (ankle-brachial index < or =0.90) were screened for clinical risk factors and cardiac medication. Follow-up end point was death from any cause. Propensity scores for statins, beta-blockers, aspirin, angiotensin-converting enzyme (ACE) inhibitors, calcium channel blockers, diuretics, nitrates, coumarins, and digoxin were calculated. Cox regression models were used to analyze the relation between cardiac medication and long-term mortality.

RESULTS

Medical history included diabetes mellitus in 436 patients (18%), hypercholesterolemia in 581 (24%), smoking in 837 (35%), hypertension in 1,162 (48%), coronary artery disease in 1,065 (44%), and a history of heart failure in 214 (9%). Mean ankle-brachial index was 0.58 (+/-0.18). During a median follow-up of eight years, 1,067 patients (44%) died. After adjustment for risk factors and propensity scores, statins (hazard ratio [HR] 0.46, 95% confidence interval [CI] 0.36 to 0.58), beta-blockers (HR 0.68, 95% CI 0.58 to 0.80), aspirins (HR 0.72, 95% CI 0.61 to 0.84), and ACE inhibitors (HR 0.80, 95% CI 0.69 to 0.94) were significantly associated with a reduced risk of long-term mortality.

CONCLUSIONS

On the basis of this observational longitudinal study, statins, beta-blockers, aspirins, and ACE inhibitors are associated with a reduction in long-term mortality in patients with PAD.