Cardioprotective effect of prior beta-blocker therapy in reducing creatine kinase-MB elevation after coronary intervention: benefit is extended to improvement in intermediate-term survival

Nebivolol compared with metoprolol for erectile function in males undergoing coronary artery bypass graft

OBJECTIVE

The aim of this study was to evaluate erectile function in males undergoing coronary artery bypass graft (CABG) while on two different adrenoceptor beta-blocker regimens, namely nebivolol and metoprolol. We hypothesize that the negative effects of cardiopulmonary bypass on erectile function may be possibly attenuated by preferring a vasodilating selective β1-blocker, nebivolol, to metoprolol as an anti-ischemic and antiarrhythmic agent in males undergoing CABG.

METHODS

This randomized, double-blind, prospective clinical study was conducted in patients scheduled for CABG surgery between February 2012 and June 2014. A total of 60 consecutive patients who met inclusion criteria were randomized and divided into the following two groups: N group, which received 5 mg of nebivolol orally for 2 weeks before surgery plus 12 weeks after surgery or M group, which received 50 mg of metoprolol orally for the same period. All patients were evaluated by the erectile function domain of the International Index of Erectile Function-5 (IIEF-5) at the time of admission (before starting the beta-blocker) and 3 months after surgery.

RESULTS

In the metoprolol group, the mean IIEF-5 score decreased significantly from a baseline of 15.2±5.8 to 12.9±5.8 (p<0.001), but in the nebivolol group, this difference was not significant (from a baseline 12.9±5.5 to 12.4±5.5, p=0.053). In all patients, the mean IIEF-5 score decreased significantly from a baseline of 14.0±5.7 to 12.6±5.6 (p<0.001).

CONCLUSION

Although erectile function in males undergoing CABG surgery decreases when metoprolol is used, nebivolol exerts protective effects on erectile function against the disruptive effects of cardiopulmonary bypass in patients undergoing CABG.

Vasoactive and Antiarrhythmic Drugs During Percutaneous Coronary Intervention

The objective in percutaneous coronary intervention (PCI) is to treat flow-limiting atherothrombotic coronary plaques mechanically. Many types of antithrombotic drugs are used to prevent ischemic complications during manipulation of catheters, guidewires, balloons, and stents in coronary arteries while minimizing the risk of bleeding. However, many other types of pharmacologic agents are also used to facilitate PCI. This review focuses on the most commonly used adjunct drugs during PCI. In addition, a recommendation of which drugs should be stopped or interrupted in patients undergoing PCI is provided.

Suppression of Myocardial Injury Markers following Percutaneous Coronary Interventions by Pre-treatment with Carvedilol

BACKGROUND

Retrospective studies and clinical trials have indicated that β-receptor blockers have an influential role in improving survival and reducing risk of recurrent infarction in patients with myocardial infarction. However, there is still controversy regarding the effects of β-receptor blockers on the markers of myocardial infarction following percutaneous coronary interventions (PCI).

OBJECTIVE

The aim of this study was to evaluate the pre-treatment effect of Carvedilol on markers of myocardial injury in patients undergoing elective PCI.

METHOD AND MATERIALS

In this clinical trial patients undergoing elective PCI were categorized randomly in the Carvedilol group including 100 patients who received two doses of 12.5 mg, 6 and 12 hours prior to PCI, and the control group (105 patients). Blood samples were obtained to analyse cardiac biomarker, 12 and 24 hours after PCI.

RESULTS

The clinical features were not significantly different between the two groups. A increase in the level of Troponin I was observed in the control group 24 hours following PCI (P=0.042), whereas this rise in troponin I was slight and insignificant in the Carvedilol group (P>0.05). some difference was observed between the two groups in regard to the level of CPK-MB after PCI (P=0.041).

CONCLUSION

The findings of our study indicate that pre-treatment with Carvedilol confers cardio-protection by limiting the rise of markers of myocardial injury following PCI.

Intracoronary followed by intravenous administration of the short-acting β-blocker landiolol prevents myocardial injury in the face of elective percutaneous coronary intervention

BACKGROUND

Myocardial injury during elective percutaneous coronary intervention (PCI) is associated with higher subsequent cardiac events and mortality. β-Blockers have been used to reduce myocardial injury during ischemia and reperfusion. We investigated whether intracoronary followed by intravenous administration of the short-acting β-blocker landiolol prevents myocardial injury in the face of elective PCI.

METHODS AND RESULTS

Patients undergoing elective PCI (n=70) were randomly assigned to the landiolol (n=35) or control (n=35) group. Landiolol or saline was administered into target vessels through a balloon catheter for 1min before and after first balloon inflation followed by continuous intravenous administration for 6h after PCI. The incidence of myocardial injury defined by cardiac troponin-I (cTnI) >/=0.05 ng/ml was 79% of the patients in the control group compared to 56% in the landiolol group (p=0.04). The cTnI level at 24h after PCI tended to be lower in the landiolol group (0.57 ± 1.14 versus 1.27 ± 2.48 ng/ml; p=0.07), while the CK-MB level was not significantly different between the landiolol and control groups. The incidence of peri-procedural myocardial infarction defined by cTnI >/=0.12 ng/ml was significantly (p=0.02) lower in the landiolol group (41%) compared to the control group (70%). There was no incidence of coronary spasm, hypotension, bradycardia or heart failure during and after PCI in the two groups.

CONCLUSIONS

Brief intracoronary followed by continuous intravenous administration of landiolol is safe and effective for myocardial protection in the face of elective PCI.

[Modulation of the beta-adrenergic system during acute myocardial infarction: rationale for a new clinical trial]

Acute myocardial infarction is caused by sudden coronary artery occlusion. Persistent ischemia results in necrosis of the myocardial tissue supplied by the occluded vessel. It has recently been shown that the final size of the infarct is a major predictor of future clinical events, and is, therefore, used as a surrogate outcome in clinical trials. Moreover, it has become clear that the duration of ischemia in the main determinant of the success of myocardial salvage (i.e. of non-necrotic at-risk myocardium). In addition to minimizing the time between symptom onset and reperfusion, there is considerable interest in finding therapies that can further limit the size of the infarction (i.e. cardioprotective therapies) and they are the focus of numerous clinical studies. Oral β-blockade within the first few hours of an AMI is a class-IA indication in clinical practice guidelines. However, early intravenous β-blockade, even before coronary artery reperfusion, is not routinely recommended. Preclinical research has demonstrated that the selectiveβ1-blocker metoprolol is able to reduce the infarct size only when administered before coronary artery reperfusion, which indicates that its cardioprotective properties are secondary to its ability to reduce reperfusion injury. In addition, retrospective studies of AMI suggest that starting intravenous β-blockade early has clinical benefits (i.e. lower mortality and better recovery of left ventricular contractility) in patients without contraindications. Our general hypothesis is that early administration of metoprolol (i.e. intravenously before reperfusion) results in smaller infarcts than administering the drug orally after reperfusion. The Effect of METOprolol in CARDioproteCtioN during an acute myocardial InfarCtion (METOCARD-CNIC) trial will test this hypothesis in patients with ST-segment elevation AMI.

Pharmacological prevention of peri-, and post-procedural myocardial injury in percutaneous coronary intervention

In recent years, percutaneous coronary intervention (PCI) has become a well-established technique for the treatment of coronary artery disease. PCI improves symptoms in patients with coronary artery disease and it has been increasing safety of procedures. However, peri- and post-procedural myocardial injury, including angiographical slow coronary flow, microvascular embolization, and elevated levels of cardiac enzyme, such as creatine kinase and troponin-T and -I, has also been reported even in elective cases. Furthermore, myocardial reperfusion injury at the beginning of myocardial reperfusion, which causes tissue damage and cardiac dysfunction, may occur in cases of acute coronary syndrome. Because patients with myocardial injury is related to larger myocardial infarction and have a worse long-term prognosis than those without myocardial injury, it is important to prevent myocardial injury during and/or after PCI in patients with coronary artery disease. To date, many studies have demonstrated that adjunctive pharmacological treatment suppresses myocardial injury and increases coronary blood flow during PCI procedures. In this review, we highlight the usefulness of pharmacological treatment in combination with PCI in attenuating myocardial injury in patients with coronary artery disease.

Lethal myocardial reperfusion injury: a necessary evil?

Despite being the most effective means of limiting infarct size, coronary reperfusion comes at a price and induces additional damage to the myocardium. Lethal reperfusion injury (death of myocytes that were viable at the time of reperfusion) is an increasingly acknowledged phenomenon. There are many interconnected mechanisms involved in this type of cell death. Calcium overload (generating myocyte hypercontracture), rapid recovery of physiological pH, neutrophil infiltration of the ischemic area, opening of the mitochondrial permeability-transition-pore (PTP), and apoptotic cell death are among the more important mechanisms involved in reperfusion injury. The activation of a group of proteins called reperfusion injury salvage kinases (RISK) pathway confers protection against reperfusion injury, mainly by inhibiting the opening of the mitochondrial PTP. Many interventions have been tested in human trials triggered by encouraging animal studies. In the present review we will explain in detail the main mechanism involved in reperfusion injury, as well as the various approaches (pre-clinical and human trials) performed targeting these mechanisms. Currently, no intervention has been consistently shown to reduce reperfusion injury in large randomized multicenter trials, but the research in this field is intense and the future is highly promising.

The cardioprotection granted by metoprolol is restricted to its administration prior to coronary reperfusion

BACKGROUND

Myocardial infarct size is a strong predictor of cardiovascular events. Intravenous metoprolol before coronary reperfusion has been shown to reduce infarct size; however, it is unknown whether oral metoprolol initiated early after reperfusion, as clinical guidelines recommend, is similarly cardioprotective. We compared the extent of myocardial salvage associated with intravenous pre-reperfusion-metoprolol administration in comparison with oral post-reperfusion-metoprolol or placebo. We also studied the effect on suspected markers of reperfusion injury.

METHODS

Thirty Yorkshire-pigs underwent a reperfused myocardial infarction, being randomized to pre-reperfusion-metoprolol, post-reperfusion-metoprolol or placebo. Cardiac magnetic resonance imaging was performed in eighteen pigs at day 3 for the quantification of salvaged myocardium. The amounts of at-risk and infarcted myocardium were quantified using T2-weighted and post-contrast delayed enhancement imaging, respectively. Twelve animals were sacrificed after 24h for reperfusion injury analysis.

RESULTS

The pre-reperfusion-metoprolol group had significantly larger salvaged myocardium than the post-reperfusion-metoprolol or the placebo groups (31 ± 4%, 13 ± 6%, and 7 ± 3% of myocardium at-risk respectively). Post-mortem analyses suggest lesser myocardial reperfusion injury in the pre-reperfusion-metoprolol in comparison with the other 2 groups (lower neutrophil infiltration, decreased myocardial apoptosis, and higher activation of the salvage-kinase phospho-Akt). Salvaged myocardium and reperfusion injury pair wise comparisons proved there were significant differences between the pre-reperfusion-metoprolol and the other 2 groups, but not among the latter two.

CONCLUSIONS

The intravenous administration of metoprolol before coronary reperfusion results in larger myocardial salvage than its oral administration initiated early after reperfusion. If confirmed in the clinical setting, the timing and route of β-blocker initiation could be revisited.

Baseline inflammation is not predictive of periprocedural troponin elevation after elective percutaneous coronary intervention

High-sensitivity C-reactive protein predicts future cardiovascular events in both healthy individuals and patients with unstable and stable coronary syndromes. Few data are available about the incidence and the relation to inflammation of troponin elevation following percutaneous coronary intervention (PCI), a potential predictor of longterm outcome. We sought to confirm the impact of embolization on long-term outcome and evaluate the ability of baseline inflammation to predict troponin elevation induced by PCI. We prospectively analyzed 200 patients treated by PCI for stable or Braunwald IIA class unstable angina. The patients were recruited between January 1997 and May 1999, and the population was followed during a mean follow-up of 32 months. Major adverse cardiac events (MACEs) were defined as the occurrence of death, myocardial infarction or recurrent angina requiring repeat PCI, or coronary artery bypass grafting. During the follow-up period, 58 MACEs were observed. By multivariate analysis, independent predictors for the occurrence of MACEs were unstable angina and troponin I level after PCI (P < 0.0001 for both). No correlation was found between baseline inflammation and significant troponin I elevation post PCI and by multivariate analysis, no biological variable was a predictor of troponin I elevation post PCI. Baseline inflammation cannot predict onset of minor myonecrosis damage (expressed by troponin elevation) induced by PCI, a significant predictor of long-term outcome in this setting.

The effects of prior calcium channel blocker therapy on creatine kinase-MB levels after percutaneous coronary interventions

Background:

Use of intracoronary calcium channel blockers (CCBs) during percutaneous coronary intervention (PCI) has been shown to have favorable effects on coronary blood flow. We aimed to investigate the effects of CCBs administrated perorally on creatine kinase-MB (CK-MB) levels in patients undergoing elective PCI.

Methods:

A total of 570 patients who underwent PCI were evaluated for CK-MB elevation. Patients who were on CCB therapy when admitted to the hospital constituted the CCB group. No CCBs were given to the rest of the patients during the periprocedural period and these patients served as the control group. Blood samples for CK-MB were obtained before and at 6 h, 24 h, and 36 h after the procedure.

Results:

217 patients were in the CCB group (mean age 60.2 ± 9.3 years, 162 males), and 353 were in the control group (mean age 60.0 ± 10.1 years, 262 males). CK-MB levels increased above the normal values in 41 patients (18.9%) of the CCBs group and in 97 patients (27.5%) of the control group (p = 0.02). Median CK-MB levels were significantly higher in the control group for all studied hours (for all p < 0.05).

Conclusions:

Prior oral CCB therapy may have favorable effects in preventing myocyte necrosis after elective PCI.

Troponin ratio and risk stratification in subjects with acute coronary syndrome undergoing percutaneous coronary intervention

BACKGROUND

Cardiac enzyme release after percutaneous coronary intervention (PCI) seems to play a role in risk stratification. After PCI, CK-MB plasmatic concentrations three times above the upper level of normal (ULN) are currently the most used risk stratification parameters. We sought to assess whether peak cardiac troponin I (cTn-I) concentration/base concentration ratio (PBTR) may act as a predictor of major adverse cardiac events (MACEs) after PCI, regardless of cTn-I ULN.

METHODS

We evaluated 326 consecutive patients with acute coronary syndrome (ACS) who underwent PCI. Baseline and post-PCI cTn-I values were evaluated over serial blood samples every 6h for at least 72h. Patients were further divided into four groups according to their PBTR values (<1, 1-4, 4-10, >10). MACEs were recorded over a 6-month follow-up period. Patients with primary PCI or unsuccessful PCI were excluded from the study.

RESULTS

Higher values of PBTR significantly correlated with a worse prognosis at 6 months (<1, 16.30% of MACEs; 1-4, 19.42%; 4-10, 24.39%; >10, 35.63%; p<0.05), both in Q-wave myocardial infarction (MI) and unstable angina (UA) subgroups. The correlation remained statistically significant, even considering subjects with peak cTn-I less than three times the ULN (p < 0.05) and after correction for age, gender, risk factors, diagnosis (MI versus UA), and peak cTn-I levels in a multiple Cox' regression analysis (HR 1.62, p<0.05).

CONCLUSIONS

PBTR is an independent predictor of MACEs after PCI in a 6-month follow-up period. This risk stratification tool may be useful to predict adverse events in PCI patients, even in the case of apparently non-elevated peak cTn-I concentrations.

Early metoprolol administration before coronary reperfusion results in increased myocardial salvage: analysis of ischemic myocardium at risk using cardiac magnetic resonance

BACKGROUND

Beta-blockers improve clinical outcome when administered early after acute myocardial infarction. However, whether beta-blockers actually reduce the myocardial infarction size is still in dispute. Cardiac magnetic resonance imaging can accurately depict the left ventricular (LV) ischemic myocardium at risk (T2-weighted hyperintense region) early after myocardial infarction, as well as the extent of necrosis (delayed gadolinium enhancement). The aim of this study was to determine whether early administration of metoprolol could increase myocardial salvage, measured as the difference between the extent of myocardium at risk and myocardial necrosis.

METHODS AND RESULTS

Twelve Yorkshire pigs underwent a 90-minute left anterior descending coronary occlusion, followed by reperfusion. They were randomized to metoprolol (7.5 mg during myocardial infarction) or placebo. Global and regional LV function, extent of myocardium at risk, and myocardial necrosis were quantified by cardiac magnetic resonance imaging studies performed 4 and 22 days after reperfusion in 10 survivors. Despite similar extent of myocardium at risk in metoprolol- and placebo-treated pigs (30.9% of LV versus 30.6%; P=NS), metoprolol resulted in 5-fold-larger salvaged myocardium (32.4% versus 6.2% of myocardium at risk; P=0.015). The LV ejection fraction significantly improved in metoprolol-treated pigs between days 4 and 22 (37.2% versus 43.0%; P=0.037), whereas it remained unchanged in pigs treated with placebo (35.1% versus 35.0%; P=NS). The extent of myocardial salvage was related directly to LV ejection fraction improvement (P=0.031) and regional LV wall motion recovery (P=0.039) at day 22.

CONCLUSIONS

Early metoprolol administration during acute coronary occlusion increases myocardial salvage. The extent of myocardial salvage, measured as the difference between myocardium at risk and myocardial necrosis, was associated with regional and global LV motion improvement.

Does pravastatin therapy affect cardiac enzyme levels after percutaneous coronary intervention?

Serum cardiac enzyme elevation after percutaneous coronary intervention (PCI), a relatively common complication, is a prognostic determinant of long-term outcome in patients who undergo these procedures. Statins are postulated to reduce such complications. This study investigated the short-term effects of pravastatin on serum creatine kinase myocardial isoform (CK-MB) and serum cardiac troponin I (cTpI) levels after elective PCI. Of 93 patients studied, 72 (77.4%) were men, and 21 (22.6%) were women (mean age, 58.9+/-11.0 y). Patients were randomly divided into 3 groups before they underwent elective PCI. Preoperatively, group 1 patients (n=30) received pravastatin 10 mg/d, and group 2 patients (n=29) received pravastatin 40 mg/d. Control group patients (n=34) received no lipid-lowering medication. Serum CK-MB and serum cTpI levels were measured preoperatively and then again at 6, 24, and 36 h postoperatively. Demographic features of patients and characteristics of the PCI procedure, including number of vessels/lesions and duration and number of inflations, did not differ among groups (P>.05). Mean serum CK-MB and serum cTpI levels were significantly increased after PCI in all patients (P<.001). When compared with control group patients, those given pravastatin did not experience significantly lowered postprocedural serum CK-MB or serum cTpI levels (P>.05). Preprocedural pravastatin therapy at dosages of 10 mg/d and 40 mg/d seems inadequate for preventing serum cardiac enzyme elevations during short-term follow-up after PCI. Additional research on this topic is recommended.

Predictors of periprocedural creatine kinase-myocardial band elevation complicating elective percutaneous coronary intervention

Limited data are available regarding the predictors of periprocedural creatine kinase-MB (CK-MB) isoenzyme increase after elective percutaneous coronary intervention (PCI) in the stenting era. We explored the predictors of periprocedural CK-MB increase in 882 consecutive patients with normal preprocedural CK-MB who underwent 919 angiographically successful elective PCIs with (n = 814) or without (n = 105) stenting. Patients were categorized into 3 groups based on their peak CK-MB levels after PCI: (1) normal CK-MB (n = 761), (2) minor CK-MB increase (CK-MB 1 to 3 times normal, n = 112), and (3) major CK-MB increase (CK-MB >3 times normal, n = 46). By logistic regression analysis, independent predictors for minor CK-MB increase included thrombus (odds ratio [OR] 5.09, p = 0.001), platelet IIb/IIIa antagonist use (OR 0.53, p <0.01), number of lesions treated (per additional lesion, OR 1.54, p <0.01), maximum balloon size (per millimeter increase, OR 1.57, p <0.05), American College of Cardiology/American Heart Association type C lesion (OR 1.68, p <0.05), sustained chest pain during procedure (OR 1.94, p <0.05), dissection (OR 2.05, p <0.05), and transient side branch occlusion (OR 4.54, p <0.05). Independent predictors for major CK-MB increase were chest pain at end of procedure (OR 9.66, p <0.001), type C lesion (OR 2.42, p <0.05), Canadian Cardiovascular Society angina class III to IV (OR 3.32, p <0.05), thrombus (OR 5.09, p = 0.001), and abrupt closure (OR 5.30, p <0.05). In conclusion, baseline clinical and angiographic characteristics and procedural complications were associated with minor and major CK-MB increases. Patients with chest pain at the end of the procedure were at the highest risk for major CK-MB increase.

Percutaneous coronary intervention for major bifurcation lesions using the simple approach: risk of myocardial infarction

BACKGROUND

Recent data has suggested that simple (main vessel only) stenting is the preferred approach for patients with bifurcation lesions. We sought to determine the feasibility and outcomes of this approach in a year long inclusive registry.

METHODS

From August, 2004-2005, a registry of 1,600 consecutive patients undergoing PCI was reviewed. Patients undergoing PCI for major bifurcation lesions--> or =70% stenosis in a major (> or =2 mm) side branch and/or main vessel--were identified by review of the angiograms. Angiographic, clinical and treatment predictors of final SB compromise (> or =70% stenosis and/or less than TIMI 3 final flow) were identified.

RESULTS

Hundred and fifty eight patients who underwent initial stenting of the main vessel with subsequent rescue of the side branch if SB compromise occurred ("Provisional Main Vessel Stenting") comprised the analysis population. Permanent SB compromise occurred in 16% of patients and was associated with an increased risk of large periprocedural MI and renal failure. Independent predictors of permanent SB compromise were lack of pre-PCI beta blockers, presence of diabetes mellitus, main vessel eccentric lesion and small SB vessel diameter.

CONCLUSION

Among unselected patients with major bifurcation lesions undergoing a "simple" stenting approach, there is a significant rate of large periprocedural infarction and side branch compromise.

Randomized Trial of Statin Administration for Myocardial Injury

BACKGROUND

Minor myocardial damage after percutaneous coronary intervention (PCI) is associated with cardiac risks, which statins seem to reduce. The aim of this study was to examine whether intensive lipid-lowering therapy is more effective in decreasing the risk of cardiac injury after PCI than moderate lipid-lowering therapy.

METHODS AND RESULTS

Subjects comprised 42 patients with stable angina without previous statin treatment, randomly assigned to either an intensive lipid-lowering group (Group A: target low-density lipoprotein-cholesterol (LDL-C)<70 mg/dl) or a moderate lipid-lowering group (Group B: target LDL-C<100 mg/dl) 2 weeks before PCI. All patients took statins to reach target LDL-C levels. Incidence of periprocedural myocardial injury was assessed by analyzing levels of creatine kinase myocardial isozyme (CK-MB) and cardiac troponin T (TnT) before and 6, 12 and 24 h after PCI. Minor myocardial damage was defined as TnT elevation to >0.01 ng/ml. Frequency of minor myocardial damage was 14.2% in Group A and 47.6% in Group B (p=0.043). CK-MB was above the upper limit of normal (ULN) in 19% of Group A and 33.3% of Group B (p=0.44), and CK-MB was >3x ULN in 9.5% of Group A and 19% of Group B (p=0.66).

CONCLUSIONS

Intensive lipid-lowering therapy before PCI reduces minor myocardial damage during PCI with stenting compared with moderate lipid-lowering therapy.

Does diagnostic coronary angiography induce significant coronary microembolization in stable, ischemic patients? A prospective study

BACKGROUND

Although microembolization during percutaneous coronary interventions is a frequent event, the extent of possible microembolization during diagnostic coronary angiography is unknown. The aim of the study was to investigate whether diagnostic coronary angiography results in coronary microembolization and consequent subtle, subclinical myocardial necrosis with enzyme elevations.

METHODS

Fifty-three consecutive patients underwent diagnostic coronary angiography due to inducible ischemia. Creatine kinase MB isoenzyme (CK MB) and cardiac troponin I (cTnI) were used as sensitive surrogate markers of myocardial necrosis. Serial measurements, before, and 6 and 24 hours following a diagnostic procedure, were performed.

RESULTS

Baseline cTnI was below the limits of detection in all patients (<0.20 ng/mL), except for one patient with 1.31 ng/mL. Baseline median CK-MB was 1.05 ng/mL (interquartile range, 0.80-1.56 ng/mL) (Fig. 1). Both at 6 and 24 hours, no patients had any increase in cTnI, with the exception of a minor increase to 0.22 ng/mL at 24 hours in one patient. At 6 hours, 25 patients had decreases in CK MB, while 22 had increases (exact P = 0.77). At 24 hours, 26 patients had decreases in CK MB and 19 patients had increases.

CONCLUSIONS

Detectable embolization with subsequent subclinical myonecrosis is an unlikely event.

Effects of Sevoflurane on Cytokine Balance in Patients Undergoing Coronary Artery Bypass Graft Surgery

OBJECTIVE

The effects of sevoflurane on proinflammatory cytokines related to ischemic-reperfusion injury are not clear. The hypothesis was tested that sevoflurane decreases myocardial ischemic-reperfusion injury by suppressing proinflammatory cytokines.

DESIGN

Prospective, randomized study.

SETTING

A medical university heart center.

PARTICIPANTS

Twenty-three patients undergoing coronary artery bypass surgery allocated randomly into 2 groups.

INTERVENTIONS

Anesthesia for 23 patients undergoing coronary artery bypass surgery was maintained using either fentanyl (30 microg/kg) with propofol (2-8 mg/kg/h) in the control group (n = 10) or fentanyl (30 microg/kg) with 0.5% to 1.0% sevoflurane in the sevoflurane group (n = 13).

MEASUREMENTS AND MAIN RESULTS

Interleukin (IL)-6, IL-8, IL-10, and IL-1 receptor antagonist (IL-1ra) were measured by enzyme-linked immunosorbent assay. Troponin-T and creatine kinase-MB isoenzyme (CK-MB) were measured by enzyme immunoassay and ultraviolet absorption spectrophotometry, respectively. Serum IL-6 and IL-8 concentrations in both groups increased significantly over baseline from 60 minutes after declamping the aorta (p < 0.001). The increases were greater in the control group than in the sevoflurane group (p < 0.05). Serum IL-10 and IL-1ra concentrations in both groups increased significantly over baseline from 60 minutes after declamping the aorta (p < 0.001). There were no differences between the two groups. Serum troponin-T and CK-MB concentrations increased significantly in both groups from 60 minutes after declamping the aorta (p < 0.001); the increases were greater in the control group (p < 0.05).

CONCLUSION

Sevoflurane suppressed the production of IL-6 and IL-8, but not IL-10 and IL-1ra. Changes in the balance between pro- and anti-inflammatory cytokines may be one of the most important mechanisms of myocardial protection caused by sevoflurane.

Therapeutic hypothermia-induced pharmacokinetic alterations on CYP2E1 chlorzoxazone-mediated metabolism in a cardiac arrest rat model*

OBJECTIVES

Therapeutic hypothermia has demonstrated considerable benefit in patients experiencing cardiac arrest. Despite increasing clinical use, there is a paucity of information regarding the effect of hypothermia on the disposition of medications, specifically cytochrome P450-mediated drug metabolism. The objective was to determine the effect of hypothermia after cardiac arrest on the in vivo kinetics of a cytochrome P450 (CYP2E1) probe drug, chlorzoxazone, and to investigate the mechanism of these alterations.

DESIGN

Laboratory investigation.

SETTING

University pharmacy school and animal research facility.

SUBJECTS

Sixteen male Sprague-Dawley rats.

INTERVENTIONS

An asphyxial arrest rat model was used and moderate hypothermia was induced immediately postinsult via surface cooling. Chlorzoxazone was administered as an intravenous bolus, and plasma concentrations were analyzed using high-performance liquid chromatography methods. Protein binding was analyzed using rat control plasma, and Michaelis-Menten enzyme kinetic analysis was performed at 37 degrees C and 30 degrees C using control rat microsomes at varying concentrations of chlorzoxazone.

MEASUREMENTS AND MAIN RESULTS

Moderate hypothermia after cardiac arrest in rats markedly decreased the systemic clearance of the CYP2E1 substrate, chlorzoxazone, when compared with normothermia after cardiac arrest, 1.26+/-0.34 mL/min vs. 0.580+/-0.37 mL/min (p<.001). No changes in chlorzoxazone protein binding were observed at 37 degrees C and 30 degrees C, and CYP2E1 enzyme capacity (maximum velocity) was not altered at these different incubation temperatures. However, Michaelis-Menten constant was significantly increased at 30 degrees C (551+/-150 microM) compared with incubations at 37 degrees C (255+/-52 microM, p<.01).

CONCLUSIONS

Moderate hypothermia markedly reduces the systemic clearance of chlorzoxazone in cardiac arrest rats. This results from hypothermia-induced decreases in the CYP2E1 enzyme affinity for the substrate chlorzoxazone. This is the first systematic mechanistic investigation of the effect of hypothermia on CYP2E1-mediated metabolism.

Nicorandil reduces the incidence of minor cardiac marker elevation after coronary stenting

BACKGROUND

Minor cardiac marker elevation after percutaneous coronary intervention has long-term prognostic significance. We examined whether nicorandil, a nicotinamide-nitrate ester, reduces the incidence of minor cardiac marker elevation after coronary stenting.

METHODS

Patients (n=192) undergoing coronary stenting were randomly assigned to receive nicorandil (nicorandil group, n=91) or vehicle (control group, n=101). Nicorandil (2 mug/kg/min, intravenously) was administered immediately after the patients were transferred into the catheterization laboratory and continued for 6 h. We measured the serum concentrations of creatine kinase isoenzyme MB (CK-MB) before, immediately after, and 6, 12, and 24 h after the procedure, and those of cardiac troponin T (cTnT) 24 h after the procedure.

RESULTS

There was no significant difference in clinical background between the 2 groups. The nicorandil group showed a significantly lower incidence of CK-MB elevation (>1x upper limit of control range, 20 IU/l) than the control group (8.8% vs 21.8%, p<0.05). The levels of serum CK-MB in the nicorandil group were significantly lower than those in the control group (13.4+/-5.7 vs 16.5+/-9.7 IU/l, p<0.01). Similarly, the nicorandil group showed a significantly lower incidence of cTnT elevation [>1x (0.1 ng/ml) or >2x (0.2 ng/ml)] upper limit of control range than the control group (14.3% vs 26.7%, p<0.05, or 7.7% vs 17.8%, p<0.05). Serum cTnT levels were also significantly lower in the nicorandil group than in the control group (0.05+/-0.10 vs 0.15+/-0.36 ng/ml, p<0.05).

CONCLUSIONS

The results demonstrated that nicorandil reduces minor cardiac marker elevation after coronary stenting.

Effects of metoprolol therapy on cardiac troponin-I levels after elective percutaneous coronary interventions

AIMS

Beta-blockers (BBs) have been shown to improve survival and reduce the risk of re-infarction in patients following myocardial infarction. There are conflicting data about the effects of BB therapy on cardiac biomarkers after percutaneous coronary interventions (PCIs). The aim of the study was to investigate the effects of BB use on cardiac troponin-I (cTnI) levels in patients who had undergone elective PCI.

METHODS AND RESULTS

In this prospective study, 287 patients with coronary artery disease were included. Patients were randomized either to BB or control groups prior to the intervention. Blood samples for cTnI were obtained before and at 6, 24, and 36 h after the procedure. Of the 287 patients included, 143 received metoprolol succinate 100 mg/day, and 144 received no BB and served as the control group. Baseline clinical characteristics of both groups, except for history of coronary artery bypass graft surgery, were similar. We observed no significant difference in the elevation of cTnI levels between the two groups after PCI (BB group, 17 patients, 11.9%; control group, 10 patients, 6.9%; P=0.2).

CONCLUSION

Metoprolol succinate therapy seems to have no cardioprotective effect in limiting troponin-I rise after PCI.

Peri-procedural myocardial injury: 2005 update

During the past three decades, percutaneous coronary intervention has become one of the cardinal treatment strategies for stenotic coronary artery disease. Technical advances, including the introduction of new devices such as stents, have expanded the interventional capabilities of balloon angioplasty. At the same time, there has been a decline in the rate of major adverse cardiac events, including Q-wave acute myocardial infarction, emergency coronary artery bypass grafting, and cardiac death. Despite these advances, the incidence of post-procedural cardiac marker elevation has not substantially decreased since the first serial assessment 20 years ago. As of now, these post-procedural cardiac marker elevations are considered to represent peri-procedural myocardial injury (PMI) with worse long-term outcome potential. Recent progress has been made for the identification of two main PMI patterns, one near the intervention site (proximal type, PMI type I) and one in the distal perfusion territory of the treated coronary artery (distal type, PMI type II) as well as for preventive strategies. Integrating these new developments into the wealth of clinical information on this topic, this review aims at giving a current perspective on the entity of PMI.

Percutaneous coronary interventions for coronary artery disease: the long and short of optimizing medical therapy

Atherosclerosis is a dynamic process and timely introduction of pharmacological treatment can have a significant bearing on the patient's health and outcome. In addition to treating the culprit lesion mechanically, admission for percutaneous coronary interventions (PCI) for coronary artery disease (CAD) gives an opportunity for the interventional cardiologist to optimize medical therapy. The aim of this review is to provide an overview of the current medical literature pertaining to cardiovascular (CV) risk reduction and vascular event prevention in the setting of PCI, with emphasis on antiplatelet therapies, beta-blockers, HMG-Co A reductase inhibitors (statins) and angiotensin-converting enzyme inhibitors, with regard to therapy optimization during PCI and for chronic CAD. We discuss the effects of these oral therapies in reducing ischaemic events, thus augmenting the benefits of PCI, as well as preventing recurrent CV events after the procedure.

Occurrence of Non-Q wave Myocardial Infarction Following Percutaneous Coronary Intervention in the Stent Era: Systematic Monitoring of the Three Markers of Myocardial Necrosis

OBJECTIVES

To compare the elevation of the three markers total creatine kinase (CK), CK-MB mass, and troponin I (TnI) and their relationship with clinical and procedural characteristics following percutaneous coronary intervention (PCI).

METHODS

We prospectively evaluated 385 patients consecutively undergoing successful PCI. The three markers were systematically measured before and at 6, 12, and 24 hours after PCI. Any increase above the upper normal limit (UNL) of any marker has been considered abnormal when basal values were normal, while a further increase was needed when basal values were altered. Patients with ongoing acute myocardial infarction were excluded from the analysis.

RESULTS

TnI was above UNL in 183 patients (51%); in 138 (38.5%) it was the only marker altered. CK-MB mass was elevated in 12.8% patients, more than 3x UNL in 5.5% and more than 5x UNL in 2.8%. In over one half of these patients, CK-MB values peaked at 12 hours following PCI. Total CK was above UNL in 23 patients only (6.4%) and more than twice UNL in 5 (1.4%). Only 1 patient out of the 5 with CK-MB mass more than 10x UNL had total CK higher than twice UNL. In our population, post-PCI elevation of myocardial necrosis markers correlate with the occurrence of minor procedural complications (observed overall in 7.8% cases; TnI and/or CK-MB > 1xUNL 96% vs 47.5%, P < 0.001) and the presence of higher complexity clinical and/or procedural features, such as multivessel disease, multivessel or multilesion PCI, multiple stenting and use of glycoprotein IIb/IIIa inhibitors.

CONCLUSIONS

The elevation of at least one biochemical marker of myocardial necrosis is frequent following successful PCI with routine stent implantation. CK-MB mass is the most practical marker, having optimal kinetic and peaking with the first 12-18 hours post-PCI. Definitive data on the prognostic role and the applicability for the diagnosis of myocardial infarction of minor elevation of CK-MB mass or isolated increase of TnI are lacking.

Effect of beta-blocker therapy on mortality rates and future myocardial infarction rates in patients with coronary artery disease but no history of myocardial infarction or congestive heart failure

Beta-blocker therapy has been shown to benefit patients who have coronary artery disease and present with acute myocardial infarction (AMI) and/or congestive heart failure (HF). However, whether beta-blocker therapy provides a similar benefit in patients who have coronary artery disease but not AMI or HF is unknown. A population of 4,304 patients who did not have HF but did have angiographically confirmed coronary artery disease (>/=1 stenosis of >/=70%) without AMI at hospital presentation was evaluated. Baseline demographics, cardiac risk factors, clinical presentation, therapeutic procedures, and discharge medications were recorded. Patients were followed for a mean of 3.0 +/- 1.9 years (range 1 month to 6.9 years) for outcomes of all-cause death or AMI. Patients' average age was 65 +/- 11 years and 77% were men. Overall, 10% died and 5% had a nonfatal AMI. Discharge beta-blocker prescription was associated with an increased event-free AMI survival rate for all-cause death (no beta blocker 88.3%, beta blocker 94.5%, p <0.001) and death/AMI (no beta blocker 83.4%, beta blocker 89.2%, p <0.001) but not non-fatal AMI (no beta blocker 93.6%, beta blocker 94.1%, p = 0.60). After adjustment for 16 covariates, including statin prescription, angiotensin-converting enzyme inhibitor prescription, and type of baseline therapy, the effect of beta blockers on the combination end point of death/AMI was eliminated. However, the effect of beta blockers on death remained (hazard ratio 0.66, 95% confidence interval 0.47 to 0.93, p = 0.02). Thus, beta blockers are clearly indicated for most patients who have HF or AMI, and our results suggest that patients who have coronary artery disease without these conditions have approximately the same protective benefit against death. No effect was observed on longitudinal incidence of AMI or the combination of death/nonfatal MI.

Under-diagnosis of diabetes mellitus in patients with coronary artery disease

BACKGROUND

The uptake of medical treatment in patients with coronary artery disease may be suboptimal. Our intention was to review the medical treatment of these patients in the light of current evidence.

METHODS

One hundred ninety six consecutive patients with known or suspected coronary artery disease attending a tertiary centre for day case cardiac catheterisation were assessed. Fasting blood samples were sent for glucose and cholesterol. The results of coronary angiography and left ventriculography and any changes in medications were noted.

RESULT

One hundred eighty two patients (93%) had fasting blood samples taken. The management of cholesterol in patients with coronary artery disease has improved since 1994. We have demonstrated the benefit of taking fasting blood samples in patients attending for day case angiography: 10% of non-diabetics actually had fasting blood glucose levels of greater than 7.0 mmol/l. All of these newly diagnosed diabetics had coronary artery disease. A further 9% of non-diabetics had impaired fasting glycaemia; 69% had coronary artery disease and 8% had left ventricular dysfunction. Among patients with coronary artery disease, there was a statistically significant increase on most categories of medications on discharge compared to admission. For those with left ventricular dysfunction, there was a statistically significant increase in the use of Angiotensin-Converting-Enzyme (ACE)-inhibitors.

CONCLUSION

Diabetes mellitus is under-diagnosed in patients with coronary heart disease. They are at higher risk of coronary artery disease and therefore need intensive management. Testing all patients attending for day case cardiac catheterisation for fasting glucose would enable diagnosis and initiation of treatment of a high-risk group.

Anemia Is an Independent Predictor of Mortality After Percutaneous Coronary Intervention

OBJECTIVES

The aim of the present study was to assess whether anemia is a marker of increased risk during interventional procedure and poor midterm survival after percutaneous coronary intervention (PCI).

BACKGROUND

Anemia is associated with increased risk of mortality in patients with heart failure and myocardial infarction (MI).

METHODS

We examined the outcomes of 6,116 consecutive PCI patients based on the hemoglobin (Hb) value before the interventional procedure. Patients were divided into three groups based on the baseline Hb level (g/l): Hb <10 = severe anemia; Hb 10 to 12 = mild anemia; Hb >12 = no anemia.

RESULTS

The presence of anemia is associated with higher 30-day major adverse cardiac events, post-PCI peak troponin and creatine kinase-MB fraction, and a longer length of stay. After controlling for multiple covariates, significant difference in one-year survival was noted in the anemic groups compared with no anemia group (adjusted hazard ratio for Hb 10 to 12: 1.5 [95% confidence interval 1.3 to 1.8]; for Hb <10: 1.8 [95% confidence interval 1.3 to 2.3]; p = 0.004.) This adverse effect of anemia on survival was noted in all three presenting clinical syndromes (stable angina, unstable angina, and MI).

CONCLUSIONS

Anemia is an independent predictor of mortality after PCI and is associated with higher short-term adverse procedural events.

Impact of intravenous Beta-Blockade before primary angioplasty on survival in patients undergoing mechanical reperfusion therapy for acute myocardial infarction

OBJECTIVES

We sought to examine the effect of intravenous beta-blockers administered before primary percutaneous coronary intervention (PCI) on survival and myocardial recovery after acute myocardial infarction (AMI).

BACKGROUND

Studies of primary PCI but not thrombolysis have suggested that beta-blocker administration before reperfusion may enhance survival. Whether oral beta-blocker use before admission modulates this effect is unknown.

METHODS

The Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) trial randomized 2082 AMI patients to either stenting or balloon angioplasty, each +/- abciximab. In accordance with the protocol, intravenous beta-blockers were administered before PCI in the absence of contraindications.

RESULTS

A total of 1136 patients (54.5%, BB+ group) received beta-blockers before PCI, whereas 946 (45.5%, BB- group) did not. The 30-day mortality was significantly lower in the BB+ group than in the BB- group (1.5% vs. 2.8%, p = 0.03), an effect entirely limited to patients who had not been receiving beta-blockers before admission (1.2% vs. 2.9%, p = 0.007). In contrast, no survival benefit with pre-procedural beta-blockers was observed in patients receiving beta-blockers at home (3.3% vs. 1.9%, respectively, p = 0.47). By multivariate analysis, pre-procedural beta-blocker use was an independent predictor of lower 30-day mortality among patients without previous beta-blocker therapy (relative risk = 0.38 [95% confidence interval 0.17 to 0.87], p = 0.02). The improvement in left ventricular ejection fraction from baseline to seven months was also greater after intravenous beta-blockers (3.8% vs. 1.3%, p = 0.01), an effect limited to patients not receiving oral beta-blockers before admission.

CONCLUSIONS

In patients with AMI undergoing primary PCI, myocardial recovery is enhanced and 30-day mortality is reduced with pre-procedural intravenous beta-blockade, effects confined to patients untreated with oral beta-blocker medication before admission.

C-reactive protein and myocardial infarction during percutaneous coronary intervention

OBJECTIVE

To evaluate the prognostic information of preprocedural C-reactive protein (CRP) levels in serum to predict myocardial infarction during percutaneous coronary interventions (PCI).

DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

A total of 400 consecutive patients with normal serum troponin T levels (</=0.03 microg L-1) presenting with stable or unstable angina pectoris.

INTERVENTIONS

PCI.

MAIN OUTCOME MEASURES

C-reactive protein levels in serum measured by a high sensitive method. Myocardial infarction defined as a serum troponin T elevation the day after PCI to a level >0.05 microg L-1.

RESULTS

Eighty-three patients (21%) experienced a myocardial infarction during PCI. The median value of CRP before the procedure was 1.83 (0.12-99.7) mg L-1. No difference was seen in CRP levels before PCI between patients without or with myocardial infarction during PCI. Multivariate analysis identified stent implantation (OR 2.68, 95% CI 1.18-7.28, P = 0.03), procedure time (OR 2.15, 95% CI 1.28-3.67, P < 0.005) and complications during the procedure (OR 3.62, 95% CI 1.72-7.58, P < 0.001) as independent predictors of myocardial infarction during PCI.

CONCLUSION

Increased CRP levels in serum before PCI were not associated with myocardial infarction during the procedure. Furthermore, patients with an expected long procedure and a high probability of stent implantation have an increased risk of developing myocardial infarction during PCI. This finding may be useful to help the operator to decide the antithrombotic regime before, during and after the procedure and the need for observation after the procedure.

Current status of rotational atherectomy

Despite the increasing use of percutaneous transluminal coronary angioplasty and intracoronary stent placement for the treatment of obstructive coronary artery disease, a large subset of coronary lesions cannot be adequately treated with balloon angioplasty and/or intracoronary stenting alone. Such lesions are often heavily calcified or fibrotic and undilatable with the present balloon technology and attempts to treat them with balloon angioplasty or intracoronary stent placement often lead to vessel dissection or incomplete stent deployment with resultant adverse outcomes. Rotational atherectomy remains a useful niche device for the percutaneous treatment of such complex lesions, usually as an adjunct to subsequent balloon angioplasty and/or intracoronary stent placement. In contrast to balloon angioplasty or stent placement that widen the coronary lumen by displacing atherosclerotic plaque, rotational atherectomy removes plaque by ablating the atherosclerotic material, which is dispersed into the distal coronary circulation. Other lesion subtypes amenable to treatment with this modality include ostial and branch-ostial lesions, chronic total occlusions, and in-stent restenosis. This review discusses the technique and principles of rotational atherectomy, the various treatment strategies for its use (including adjunctive pharmacotherapy), the lesion-specific applications for this device, and the complications unique to this modality. Recommendations are also made for its use in the current interventional era.

Prediction of outcome after percutaneous coronary intervention for the acute coronary syndrome

BACKGROUND

The seven-component Thrombolysis In Myocardial Infarction (TIMI) score has been used to risk stratify, and to guide the medical management of, patients with unstable angina or non-ST-elevation myocardial infarction. We assessed the usefulness of the risk score in predicting in-hospital and 30-day outcomes in such patients who were undergoing percutaneous coronary intervention.

METHODS

Using the TIMI score, 2501 patients with unstable angina or non-ST-elevation myocardial infarction were divided into low-risk (zero to two risk factors; n = 974), intermediate-risk (three to four risk factors; n = 1339), and high-risk (five to seven risk factors; n = 188) groups, and outcomes were compared.

RESULTS

Angiographic/clinical success and the rate of minor procedural events were similar among the three groups. A higher TIMI risk score was associated with more cardiac comorbid conditions and more complicated angiographic lesions: longer lesions (P = 0.0009), more thrombotic lesions (P = 0.03), more multivessel disease (P <0.0001), and more American College of Cardiology/American Heart Association type B2/C lesions (P = 0.05). Although the risk score did not predict interventional technical success or intraprocedural complications, a high score was associated with prolonged hospital stay, higher postprocedural peak troponin levels, and 30-day major adverse cardiac events. Stepwise logistic regression showed that in conjunction with lesion length and patient sex, a high score was an independent predictor of 30-day major adverse cardiac events (odds ratio = 2.3; 95% confidence interval: 1.1 to 4.1; C statistic = 0.62).

CONCLUSION

Although a higher TIMI risk score in patients with unstable angina or non-ST-elevation myocardial infarction who were undergoing percutaneous coronary intervention correlated with adverse clinical outcome, the score alone cannot be used to guide diagnostic or therapeutic strategies.

Continuous Quality Improvement in Medicine: Validation of a Potential Role for Medical Specialty Societies

A rigorous evaluation of the effects of continuous quality improvement (CQI) on medical practice has not yet been achieved on a large, multicenter scale. The authors sought to test whether a low-intensity CQI intervention could be used to speed the adoption of two coronary artery bypass grafting process-of-care measures on a national level. The infrastructure of the Society of Thoracic Surgeons' National Cardiac Database was used as a CQI Platform in a prospective randomized trial of CQI conducted between January 2001 and July 2002. Preoperative beta-blockade and internal mammary artery grafting in patients aged >75 years were the care processes used. Three hundred fifty-nine National Cardiac Database sites were randomized into two intervention groups (beta blocker, n=124; internal mammary artery grafting, n=114) and one control group (n=114). Each intervention arm received measure-specific information, including a call to action to a physician leader; educational products; and periodic longitudinal, nationally benchmarked, site-specific feedback. Incorporation of the specific care process into everyday clinical practice at the intervention site was the main outcome measure. The analyses included a site-level analysis of differences between pre- and postintervention measure use and a hierarchical analysis using risk-adjustment for patient characteristics and accounting for clustering due to site. Use of beta blockers increased vs. control (Delta=7% vs. Delta=4%), significant at both the site level (p=0.04) and in the hierarchical analyses (p=0.0006). Internal mammary artery graft use also increased vs. control (Delta=9% vs. Delta=5%; p=0.20 and p=0.11, respectively). However, lower volume IMA sites showed significant improvement over lower volume control sites (Delta=14% vs. Delta=8%; p=0.02 for interaction). A multifaceted, physician-led, low-intensity effort can have an impact on the adoption of care processes into national practice. This Society CQI Platform is a potential model for large-scale quality improvement efforts across all disciplines of medicine.

Prognostic significance of elevated creatine kinase MB after coronary bypass surgery and after an acute coronary syndrome: results from the GUARDIAN trial

OBJECTIVE

To determine if the correlation between magnitude of creatine kinase-myocardial band release after coronary artery bypass surgery and 6-month mortality is comparable to that of patients admitted with an acute coronary syndrome.

METHODS

The GUARDIAN trial tested the efficacy of cariporide, an Na+/H+ exchange inhibitor, on reduction of myocardial ischemia or death in high-risk patients. We compared 6-month survival in a cohort of 2332 GUARDIAN patients scheduled for coronary artery bypass surgery at entry with 4233 acute coronary syndrome patients stratified by level of creatine kinase-myocardial band release. Cumulative 6-month survival by creatine kinase-myocardial band categories was performed using life table analysis, adjusting for variables known to impact prognosis using Cox regression.

RESULTS

The 6-month mortality rates for coronary artery bypass surgery patients with peak creatine kinase-myocardial band ratios of <1, > or =1 and <5, > or =5 and <10, and > or =10 upper limits of normal (ULN) were 5.8, 2.8, 5.9, and 12.0%, respectively (P <.0001). The 6-month mortality rates for acute coronary syndrome patients with peak creatine kinase-myocardial band ratios of <1, > or =1 and <5, > or =5 and <10, and > or =10 ULN were 6.3, 9.8, 10.0, and 12.3%, respectively (P <.0001). Patients with coronary artery bypass surgery or acute coronary syndrome had similar adjusted 6-month survival estimates at normal creatine kinase-myocardial band levels and when the creatine kinase-myocardial band level was > or =10 ULN. Patients with coronary artery bypass surgery had significantly better survival at intermediate enzyme levels (> or =1 and <10 ULN; P <.001).

CONCLUSIONS

Modest elevations of creatine kinase-myocardial band release (> or =1 and <10 ULN) after coronary artery bypass surgery are not associated with adverse 6-month survival, in contrast to that seen in acute coronary syndrome patients. Routine creatine kinase-myocardial band sampling should be considered in all higher-risk patients undergoing coronary artery bypass surgery procedures to identify the sizable cohort of patients with creatine kinase-myocardial band release > or =10 ULN; these patients may benefit from postoperative angiotensin-converting enzyme inhibitor and beta-blocker therapy. Newer cardioprotective agents that reduce the number of patients with marked creatine kinase-myocardial band release are currently being tested in large randomized controlled clinical trials.

Mortality Benefit of Beta Blockade in Patients with Acute Coronary Syndromes Undergoing Coronary Intervention:

The effects of beta blocker therapy in the settings of heart failure and coronary artery disease have been well described, although little data exist in patients presenting with acute coronary syndromes undergoing percutaneous coronary intervention. The current study will attempt to evaluate the efficacy of beta blocker therapy in this setting. Pooled data from five randomized, controlled trials of abciximab during coronary intervention were used to analyze the clinical efficacy of beta blocker therapy. The pooled analysis evaluated the end points of all-cause mortality, myocardial infarction, repeat revascularization, and the combined endpoint of death and myocardial infarction in 2,894 patients. At 30 days, death occurred in 12 of 1,939 (0.6%) patients receiving beta blocker therapy and in 19 of 955 (2.0%) patients not receiving beta blocker therapy, (P < 0.001). At 6 months, death occurred in 33 of 1,939 (1.7%) patients receiving beta blocker therapy and 35 of 955 (3.7%) not receiving beta blocker therapy, (P < 0.001). After creating a propensity model and adjusting for variables predictive of mortality in the multivariable analysis, beta blocker therapy continued to be associated with a significant reduction in mortality. The findings were similar to those shown for the effects of beta blocker therapy in separate subgroups of patients with unstable angina and acute myocardial infarction. This analysis demonstrates a lower short-term mortality in patients receiving beta blocker therapy who undergo percutaneous coronary intervention for unstable angina or acute myocardial infarction.

Use of continuous quality improvement to increase use of process measures in patients undergoing coronary artery bypass graft surgery: a randomized controlled trial

CONTEXT

A rigorous evaluation of continuous quality improvement (CQI) in medical practice has not been carried out on a national scale.

OBJECTIVE

To test whether low-intensity CQI interventions can be used to speed the national adoption of 2 coronary artery bypass graft (CABG) surgery process-of-care measures: preoperative beta-blockade therapy and internal mammary artery (IMA) grafting in patients 75 years or older.

DESIGN, SETTING, AND PARTICIPANTS

Three hundred fifty-nine academic and nonacademic hospitals (treating 267 917 patients using CABG surgery) participating in the Society of Thoracic Surgeons National Cardiac Database between January 2000 and July 2002 were randomized to a control arm or to 1 of 2 groups that used CQI interventions designed to increase use of the process-of-care measures.

INTERVENTION

Each intervention group received measure-specific information, including a call to action to a physician leader; educational products; and periodic longitudinal, nationally benchmarked, site-specific feedback.

MAIN OUTCOME MEASURE

Differential incorporation of the targeted care processes into practice at the intervention sites vs the control sites, assessed by measuring preintervention (January-December 2000)/postintervention (January 2001-July 2002) site differences and by using a hierarchical patient-level analysis.

RESULTS

From January 2000 to July 2002, use of both process measures increased nationally (beta-blockade, 60.0%-65.6%; IMA grafting, 76.2%-82.8%). Use of beta-blockade increased significantly more at beta-blockade intervention sites (7.3% [SD, 12.8%]) vs control sites (3.6% [SD, 11.5%]) in the preintervention/postintervention (P =.04) and hierarchical analyses (P<.001). Use of IMA grafting also tended to increase at IMA intervention sites (8.7% [SD, 17.5%]) vs control sites (5.4% [SD,15.8%]) (P =.20 and P =.11 for preintervention/postintervention and hierarchical analyses, respectively). Both interventions tended to have more impact at lower-volume CABG sites (for interaction: P =.04 for beta-blockade; P =.02 for IMA grafting).

CONCLUSIONS

A multifaceted, physician-led, low-intensity CQI effort can improve the adoption of care processes into national practice within the context of a medical specialty society infrastructure.

Distal myocardial protection during percutaneous coronary intervention with an intracoronary beta-blocker

BACKGROUND

Experimental studies have demonstrated that intravenous beta-blocker administration before coronary artery occlusion significantly reduces myocardial injury. Clinical studies have shown that intracoronary (IC) propranolol administration before percutaneous coronary intervention (PCI) delays myocardial ischemia. The present study tested the hypothesis that IC propranolol treatment protects ischemic myocardium from myocardial damage and reduces the incidence of myocardial infarction (MI) and short-term adverse outcomes after PCI.

METHODS AND RESULTS

Patients undergoing PCI (n=150) were randomly assigned in a double-blind fashion to receive IC propranolol (n=75) or placebo (n=75). Study drug was delivered before first balloon inflation via an intracoronary catheter with the tip distal to the coronary lesion. Biochemical markers were evaluated through the first 24 hours and clinical outcomes to 30 days. Evidence of MI with creatine kinase-MB elevation after PCI was seen in 36% of placebo and 17% of propranolol patients (P=0.01). Troponin T elevation was seen in 33% of placebo and 13% of propranolol patients (P=0.005). At 30 days, the composite end point of death, postprocedural MI, non-Q-wave MI after PCI hospitalization, or urgent target-lesion revascularization occurred in 40% of placebo versus 18% of propranolol patients (hazard ratio 2.14, 95% CI 1.24 to 3.71, P=0.004).

CONCLUSIONS

IC administration of propranolol protects the myocardium during PCI, significantly reducing the incidence of MI and improving short-term clinical outcomes.

Effects of prior beta-blocker therapy on clinical outcomes after primary coronary angioplasty for acute myocardial infarction

We hypothesized that pretreatment with beta blockers may improve clinical outcomes after primary angioplasty for acute myocardial infarction. We pooled clinical, angiographic, and outcomes data on 2,537 patients enrolled in the Primary Angioplasty in Myocardial Infarction (PAMI), PAMI-2, and Stent PAMI trials. We classified patients into a beta group (n = 1,132) if they received beta-blocker therapy before primary angioplasty or a no-beta group (n = 1,405) if they did not. We evaluated procedural complications and in-hospital and 1-year outcomes (death and major adverse cardiac events [death, reinfarction, target vessel revascularization, or stroke]) between groups. Beta patients were younger, had higher systolic blood pressure and heart rate, and were more likely to be in Killip class I at admission. They had lower left ventricular ejection fraction, greater door-to-balloon time, greater likelihood of having a left anterior descending artery culprit lesion, but a similar incidence of Thrombolysis In Myocardial Infarction 3 flow after angioplasty (92.6% vs 92.7%, p = 0.91). The beta group had less procedural complications (23% vs 34%, p <0.0001) and a lower incidence of death (1.8% vs 3.7%, p = 0.0035) and major adverse cardiac events (5.5% vs 7.8%, p = 0.027) during hospitalization. At 1 year, mortality remained lower in beta patients (4.9% vs 6.7%, log-rank p = 0.055). After adjustment for baseline differences, beta patients had significantly lower in-hospital mortality (odds ratio 0.41; 95% confidence interval 0.20 to 0.84; p <0.0148) and nonsignificantly lower 1-year mortality (odds ratio 0.72; 95% confidence interval 0.47 to 1.08; p = 0.11). Thus, pretreatment with beta blockers has an independent beneficial effect on short-term clinical outcomes in patients undergoing primary angioplasty for acute myocardial infarction.

Effect of beta blockers after coronary artery bypass in postinfarct patients: what can we learn from available literature?

Studies have shown that beta adrenergic antagonist therapy benefits patients with coronary disease through reduced mortality rate after acute myocardial infarction and reduced incidence of postoperative atrial fibrillation after coronary artery bypass grafting. The long-term benefit of this therapy in survivors of myocardial infarction who are subsequently revascularized, however, has not been defined or studied rigorously. We reviewed the published data to clarify the role of beta blockade in patients who had surgical revascularization after myocardial infarction. We found that patients who received beta blockers after myocardial infarction had a reduced mortality rate and fewer cardiac events in most clinical situations, a benefit which likely extends to patients who have had subsequent surgical revascularization.

Preprocedural statin medication reduces the extent of periprocedural non-Q-wave myocardial infarction

BACKGROUND

Stenting-related myocardial injury has been recognized as a frequent and prognostically important event, the extent of which depends on microcirculatory impairment in association with platelet aggregation, inflammation, and increased oxidative stress. Recent studies underscored the non-lipid-lowering effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) with antithrombotic, antiinflammatory, and antioxidative aspects. Thus, we tested the hypothesis that preprocedural statin therapy is associated with a reduction in the extent of stenting-related myocardial injury.

METHODS AND RESULTS

We stratified 296 consecutive patients who were undergoing stenting of a de novo stenosis according to the preprocedural status of statin therapy (229 statin-treated and 67 control patients). Incidence of periprocedural myocardial injury was assessed by analysis of creatine kinase (CK; upper limit of normal [ULN] 70 IU/L for women, 80 IU/L for men) and cardiac troponin T (cTnT; bedside test; threshold 0.1 ng/mL) before and 6, 12, and 24 hours after the intervention. Relative to control patients, the incidence of CK elevation >3x ULN was more than 90% lower in statin-treated patients (0.4% versus 6.0%, P=0.01). Statin therapy was the only factor independently associated with a lower risk of CK elevation >3x ULN (OR: 0.08, 95% CI: 0.01 to 0.75; P=0.03). The overall incidences of CK and cardiac troponin T elevation were slightly lower in statin-treated than in control patients (14.4% versus 20.9%, P=0.3, and 17.9% versus 22.4%, P=0.5, respectively).

CONCLUSIONS

Preprocedural statin therapy is associated with a reduction in the incidence of larger-sized, stenting-related myocardial infarctions. Prospective, randomized trials are warranted to further assess this cardioprotective effect of statins in coronary intervention.