David Massel

Propranolol for the prevention of postoperative arrhythmias in general thoracic surgery

BACKGROUNDnPrevention of postoperative arrhythmias in patients undergoing general thoracic surgery is desirable to prevent morbidity.nnnMETHODSnA randomized, double-blind, placebo controlled trial of propranolol (10 mg every 6 hours) for 5 days was undertaken in patients undergoing major thoracic operations to determine whether arrhythmias requiring treatment could be reduced. Secondary outcomes included overall arrhythmia rate, adverse events, and length of stay. Arrhythmias were assessed by 72-hour Holter monitoring. Patients with a history of heart failure, asthma, advanced heart block, preexisting arrhythmias, sensitivity to propranolol, or use of antiarrhythmic drugs were excluded.nnnRESULTSnUsing the intention-to-treat principle there was a 70% relative risk reduction from 20% to 6% in the rate of treated arrhythmias with propranolol (p = 0.071, 95% confidence interval 0.6% to 27.2%). Overall arrhythmias were common but usually benign. Adverse effects were common, although generally mild with hypotension and bradycardia being reported more often in the propranolol group. Length of stay was not different.nnnCONCLUSIONSnThere was a trend to a reduction in the risk of perioperative arrhythmias with propranolol. Moreover, propranolol was well tolerated showing a slight increase in minor adverse events.

Antiplatelet and anticoagulation for patients with prosthetic heart valves

BACKGROUNDnPatients with prosthetic heart valves are at increased risk for valve thrombosis and arterial thromboembolism. Oral anticoagulation alone, or the addition of antiplatelet drugs, has been used to minimise this risk. An important issue is the effectiveness and safety of the latter strategy.nnnOBJECTIVESnThis is an update of our previous review; the goal was to create a valid synthesis of all available, methodologically sound data to further assess the safety and efficacy of combined oral anticoagulant and antiplatelet therapy versus oral anticoagulant monotherapy in patients with prosthetic heart valves.nnnSEARCH METHODSnWe updated the previous searches from 2003 and 2010 on 16 January 2013 and searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (2012, Issue 12), MEDLINE (OVID, 1946 to January Week 1 2013), and EMBASE (OVID, 1980 to 2013 Week 02). We have also looked at reference lists of individual reports, review articles, meta-analyses, and consensus statements. We included reports published in any language or in abstract form.nnnSELECTION CRITERIAnAll reports of randomised controlled trials comparing standard-dose oral anticoagulation to standard-dose oral anticoagulation and antiplatelet therapy in patients with one or more prosthetic heart valves.nnnDATA COLLECTION AND ANALYSISnTwo review authors independently performed the search strategy, assessed trials for inclusion and study quality, and extracted data. We collected adverse effects information from the trials.nnnMAIN RESULTSnOne new study has been identified and included in this update. In total, 13 studies involving 4122 participants were included in this review update. Years of publication ranged from 1971 to 2011. Compared with anticoagulation alone, the addition of an antiplatelet agent reduced the risk of thromboembolic events (odds ratio (OR) 0.43, 95% confidence interval (CI) 0.32 to 0.59; P < 0.00001) and total mortality (OR 0.57, 95% CI 0.42 to 0.78; P = 0.0004). Aspirin and dipyridamole reduced these events similarly. The risk of major bleeding was increased when antiplatelet agents were added to oral anticoagulants (OR 1.58, 95% CI 1.14 to 2.18; P = 0.006).For major bleeding, there was no evidence of heterogeneity between aspirin and dipyridamole and in the comparison of trials performed before and after 1990, around the time when anticoagulation standardisation with the international normalised ratio was being implemented. A lower daily dose of aspirin (< 100 mg) may be associated with a lower major bleeding risk than higher doses.nnnAUTHORS CONCLUSIONSnAdding antiplatelet therapy, either dipyridamole or low-dose aspirin, to oral anticoagulation decreases the risk of systemic embolism or death among patients with prosthetic heart valves. The risk of major bleeding is increased with antiplatelet therapy. These results apply to patients with mechanical prosthetic valves or those with biological valves and indicators of high risk such as atrial fibrillation or prior thromboembolic events. The effectiveness and safety of low-dose aspirin (100 mg daily) appears to be similar to higher-dose aspirin and dipyridamole. In general, the quality of the included trials tended to be low, possibly reflecting the era when the majority of the trials were conducted (1970s and 1980s when trial methodology was less advanced).

Instruments to measure acceptability of information and acquisition of knowledge in patients with heart failure.

Patients with heart failure suffer from poor health outcomes and require combinations of medications to treat their disease. Providing patients with knowledge through education is one mechanism to help them improve compliance with complicated treatment regimens.

Observer variability in ECG interpretation for thrombolysis eligibility: experience and context matter.

AbstractBackground: Despite the known benefit of thrombolysis it remains underutilized among eligible patients with acute myocardial infarction. We sought to determine whether potential errors in ECG interpretation might be a contributing factor and to what extent clinical history, a checklist outlining recognized inclusion criteria and a computerized interpretation would influence reliability and accuracy.nMethods: Seventy-five ECGs were interpreted on 8 separate occasions by 9 clinicians (3 cardiologists, 3 cardiology fellows, 3 medical residents) according to a 2 × 2 × 2 factorial design.nResults: The overall level of agreement among all raters was substantial with a kappa (κ) of 70.4%. Intra-observer ECG reading reliability was stronger among cardiologists (CC) as compared with cardiology fellows (CF) and medical residents (MR). Similarly, inter-observer reliability was substantial to very good and a gradient was seen with greater reliability among CC, followed by CF, then MR (P = 0.0013). CC recommended thrombolysis significantly more frequently (p < 0.001) than either CF or MR. Trainees were biased by the presence of a computerized ECG interpretation resulting in a decision to recommend thrombolysis administration less often.nConclusion: The reliability of ECG interpretation for deciding to administer thrombolysis was substantial; there was a gradient from lowest to highest commensurate with training and experience. Errors in thrombolysis eligibility are influenced by clinical history and the presence of a computerized ECG interpretation among less experienced clinicians.

Ejection fraction velocity ratio as an indicator of aortic stenosis severity.

Background: Despite the widespread use of the continuity equation in the estimation of aortic valve area (AVA) in patients with aortic stenosis, it is subject to errors, time consuming, and can be technically demanding. As such, simpler methods of assessing aortic stenosis severity have been pursued. Methods: The ejection fraction velocity ratio [EFVR = ejection fraction (%) / maximal aortic velocity (m/sec)] was compared to AVA determined with the continuity equation in 857 patients with aortic stenosis and varying degrees of LV systolic dysfunction. Severe aortic stenosis was defined as an AVA < 1.0 cm2. Results: There was good to excellent correlation between our index and aortic valve area (P < 0.001 for each ejection fraction subgroup). Receiver operating characteristic analysis showed that the EFVR functioned well with areas under the curve between 0.893 and 0.938. Conclusion: The EFVR is a simple noninvasive method for screening patients for an AVA of 1.0 cm2. It could be used as a screening test or in lieu of the continuity equation particularly when there is problematic measurement of either the LVOT diameter or velocity.

Very high coronary artery calcium score with normal myocardial perfusion SPECT imaging is associated with a moderate incidence of severe coronary artery disease.

PurposeMyocardial perfusion imaging (MPI) has limitations in the presence of balanced multivessel disease (MVD) and left main (LM) coronary artery disease, occasionally resulting in false-normal results despite the high cardiovascular risk associated with this condition. The purpose of this study was to assess the incidence of severe coronary artery disease (CAD) in the presence of a very high Agatston coronary artery calcium (CAC) score (>1,000) in stable symptomatic patients without known CAD but with normal MPI results.MethodsA total of 2,659 prospectively acquired consecutive patients were referred for MPI and evaluation of CAC score by CT. Of this patient population, 8xa0% (222/2,659) had ischemia without myocardial infarction (MI) on MPIand 11xa0% (298/2,659) had abnormal MPI (MI and/or ischemia). On presentation 1xa0% of the patients (26/2,659) were symptomatic, had a CAC score >1,000 and normal MPI results. The definition of normal MPI was strict and included a normal hemodynamic response without ischemic ECG changes and normal imaging, particularly absence of transient ischemic dilation. All of these 26 patients with a CAC score >1,000 and normal MPI findings underwent cardiac catheterization.ResultsOf these 26 patients, 58xa0% (15/26) had severe disease (≥70xa0% stenosis) leading to revascularization. Of this group, 47xa0% (7/15) underwent percutaneous intervention, and 53xa0% (8/15) underwent coronary artery bypass grafting. All of these 15 patients had either MVD (14/15) or LM coronary artery disease (1/15), and represented 0.6xa0% (15/2,659) of all referred patients (95xa0% CI 0.3xa0–xa00.9xa0%). The majority, 90xa0% (8/9), had severe CAD with typical chest pain.ConclusionA very high CAC score (>1,000) with normal MPI in a small subset of symptomatically stable patients was associated with a moderate incidence of severe CAD (95xa0% CI 37xa0–xa077xa0%). Larger studies and/or a meta-analysis of small studies are needed to more precisely estimate the incidence of CAD in this population. This study also supports the concept that a normal MPI result in patients with severe CAD may be due to balanced MVD.

An echocardiographic study of the limitations of the Tei index in aortic stenosis.

Background: The omnibus Tei index, the sum of isovolumic contraction and relaxation times divided by the ejection time, is a good indicator of global cardiac function. However, these time intervals can be influenced by valvular heart disease and the role of the Tei index among patients with aortic stenosis (AS) and left ventricular systolic dysfunction remains incompletely defined. Methods: Doppler time intervals were measured retrospectively by two observers, and the Tei index were calculated on 80 patients with various degrees of left ventricular systolic dysfunction and severity of AS. Differences between observers were resolved by consensus. Ejection fraction (EF) was visually estimated, and the aortic valve area (AVA) was calculated using the continuity equation. Results: The mean AVA was 1.1±0.5 cm2 and the mean EF was 0.39±0.15. Although correlation (r = 0.61, P < 0.001) and agreement (intraclass correlation coefficient=0.55) for the Tei index were satisfactory, there were significant differences between observers (P < 0.001). Using consensus data, the mean Tei index was 0.32±0.20 and significantly lower among patients with severe compared with less severe AS (P=0.01). The index varied inversely with left ventricular function (P=0.003). However, receiver operating characteristic analysis shows that the Tei index lacks discrimination in accurately identifying poor left ventricular function or severe AS or both. Conclusion: The Tei index varies inversely with systolic ventricular function (low index with good EF) and positively with severity of AS (low index with smaller valve area). As such, it may have limited utility among individual patients with AS.

Myocardial fibrosis is not associated with reduced quality of life in patients with dilated or hypertrophic cardiomyopathy

Background and objectives Patients with Dilated Cardiomyopathy (DCM) and Hypertrophic Cardiomyopathy (HCM) frequently demonstrate non-ischemic pattern myocardial fibrosis (MF) on delayed enhancement magnetic resonance imaging (DE-MRI). The clinical significance of this finding with respect to impact on Quality of Life (QOL) is poorly understood. In this study we identify the prevalence of MF in patients with HCM and DCM and assess its relationship with standardized measures of QOL. Methods One-hundred and seven consecutive patients with either DCM (n=50) or HCM (n=57) referred for MRI evaluation were identified. DCM was defined as a LVEF 3SD above reference myocardium) using validated commercial software. Results

Perioperative fluvastatin reduced cardiac events after noncardiac vascular surgery

Source Citation Schouten O, Boersma E, Hoeks SE, et al. Fluvastatin and perioperative events in patients undergoing vascular surgery. N Engl J Med. 2009;361:980-9. 19726772

Fondaparinux was noninferior to enoxaparin for death, MI, and refractory ischemia but reduced bleeding in angina and non-STEMI.

Source Citation Antman EM, Morrow DA, McCabe CH, et al. Enoxaparin versus unfractionated heparin with fibrinolysis for ST-elevation myocardial infarction. N Engl J Med. 2006;354:1477-88. 16537665