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ISCHAEMIC HEART DISEASE
Late risks of using drug eluting coronary stents ▸
Although good at reducing restenosis, drug eluting stents (DES) have not yet been shown to reduce mortality. There is a known risk to performing non-cardiac surgery soon after bare metal stenting, presumably from stent thrombosis when endothelialisation has not occurred. However, operations done after six weeks appear to be safe even when antiplatelet agents are stopped. The same may not be true for DES. Four case reports are presented with clopidogrel having been stopped safely six months after DES. However, with the aspirin being stopped > 30 days after the first procedure in preparation for non-cardiac surgery, 4–5 days later, in-stent thrombosis of the DES occurred. The cause is not clear, but presumably poor endothelialisation may play a part. Plan—keep the aspirin going if at all possible.
Can PCI be safely performed in institutions without cardiac surgery facilities available onsite? ▸
A retrospective study using Medicare data aimed to answer this question by analysing patient outcomes over a two year period from 178 hospitals without and 943 hospitals with onsite surgery. An overall analysis found that patients undergoing percutaneous coronary intervention (PCI) in hospitals without surgical facilities were more likely to die within 30 days of the procedure (6.0% v 3.3%), but the authors uncovered some interesting findings after accounting for baseline differences. While mortality for primary/rescue PCI was similar in hospitals regardless of whether cardiac surgery was available or not (adjusted odds ratio (OR) 0.93, 95% confidence interval (CI) 0.80 to 1.08; p = 0.34), mortality for patients in the non-primary/rescue PCI population was significantly higher in the hospitals without onsite surgery (adjusted OR 1.38, 95% CI 1.14 to 1.67; p = 0.01). Noticeably, this increase in mortality was confined to hospitals performing 50 or fewer Medicare PCIs a year. However, can this difference be explained purely by lack of readily available cardiac surgery alone? The authors themselves admit this is not an easy question to answer, but suggest differences in patient characteristics, hospital management protocols, and the inverse association of outcome with the volume of PCIs done at an institution as possible reasons.
So should all interventional procedures be performed by high volume operators in central institutions? ▸
The more percutaneous transluminal coronary angioplasties (PTCAs) performed by an operator or by a hospital each year, the lower the risk of inpatient mortality, emergency bypass surgery (CABG), and complications. To examine whether the cessation of services in low volume centres would affect patients’ access to care, these authors retrospectively examined the records of 97 401 patients undergoing PTCA in 2001 and looked specifically at the change in their travel times to hospital in two hypothetical scenarios where hospitals not performing at least 400 procedures per year closed. To find an operator who performed at least 75 procedures a year, the authors found that 99% of people would have to travel less than 50 miles extra on average. Although an important consideration, the authors conclude that travel distances are but one of many important areas to be examined before regionalisation of PTCA services could be realistically recommended.
Bleeding is a risk factor for death post-PCI ▸
An increase in the use of invasive procedures, and the expanding use of antithrombotic medications, has increased the potential for bleeding and the need for blood transfusion among patients with cardiovascular disease. To investigate this further, Rao and colleagues looked at the 30 day mortality of the 2401 patients enrolled in GUSTO IIb, PURSUIT, and PARAGON B who required at least one blood transfusion during their hospitalisation. Patients who underwent transfusion had a significantly higher unadjusted rate of 30 day death/myocardial infarction (MI) (29.24% v 10.02%; p < 0.01) compared with patients who did not; however, they were also older and had more co-morbid illness at presentation. Using Cox proportional hazards modelling, transfusion was associated with an increased hazard for 30 day death/MI (hazard ratio 2.92, 95% CI 2.55 to 3.35). The authors suggest a randomised trial is now necessary, and caution against the routine use of blood transfusion to maintain arbitrary haematocrit concentrations in stable acute coronary syndrome patients in the meantime.
Invasive treatment for high risk non-ST elevation ACS (NSTE ACS) ▸
Of the 17 926 patients analysed in the CRUSADE registry from the USA, 8037 (44.8%) underwent early cardiac catheterisation less than 48 hours following presentation. Predictors of early invasive management included cardiology care, younger age, lack of prior or current congestive heart failure, lack of renal insufficiency, ischaemic electrocardiographic changes, positive cardiac markers, white race, and male sex. Patients treated with early invasive management were more likely to be treated with medications and interventions recommended by the American College of Cardiology/American Heart Association guidelines and had a lower risk of in-hospital mortality after adjusting for differences in clinical characteristics and after comparing propensity matched pairs (2.5% v 3.7%, p < 0.001). Thus, an early invasive management strategy is not utilised in the majority of high risk patients with NSTE ACS. This strategy, when used, appears to be reserved for patients without significant co-morbidities and for those cared for by cardiologists, and is associated with a lower risk of in-hospital mortality.
Choose your hospital with care, if you can afford to ▸
It is well described that standards of cardiovascular care can vary greatly between different racial and ethnic groups in the USA; this has been ascribed to differences in clinical presentation, access to care, and clinician bias. On the whole, those from ethnic minorities tend to experience poorer standards of care. Using data from the American NRMI (National Registry for Myocardial Infarction), door-to-drug times were significantly longer for patients identified as African American/black (41.1 minutes), Hispanic (36.1 minutes), and Asian/Pacific Islander (37.4 minutes), compared with patients identified as white (33.8 minutes) (p < 0.01 for all). Door-to-balloon times for patients identified as African American/black (122.3 minutes) or Hispanic (114.8 minutes) were significantly longer than for patients identified as white (103.4 minutes) (p < 0.001 for both). However, after accounting for differences in mean times to treatment in individual hospitals, these differences were substantially reduced. For example, the difference in door-to-balloon time between African American and white patients was reduced by 33% after accounting for differences between hospitals in which the patients were treated. Although they acknowledge that the causes of ethnic disparity in time to treatment are complex, the authors conclude that a large part of the difference is accounted for by the hospital to which a patient is admitted.
Atenolol: time for a rethink? ▸
Atenolol is one of the most widely used β blockers, and β blockers as a class are often recommended as first line treatment for hypertension. But are all β blockers equal? In a search of databases, four studies compared atenolol with placebo or no treatment, and five compared atenolol with other antihypertensive drugs. Despite major differences in blood pressure lowering, there were no outcome differences between atenolol and placebo in the four studies, comprising 6825 patients, who were followed up for a mean of 4.6 years for all cause mortality (relative risk (RR) 1.01, 95% CI 0.89 to 1.15), cardiovascular mortality (RR 0.99, 95% CI 0.83 to 1.18), or myocardial infarction (RR 0.99, 95% CI 0.83 to 1.19). The risk of stroke, however, tended to be lower in the atenolol than in the placebo group (RR 0.85, 95% CI 0.72 to 1.01). When atenolol was compared with other antihypertensives, there were no major differences in blood pressure lowering between the treatment arms. The meta-analysis showed a significantly higher mortality (RR 1.13, 95% CI 1.02 to 1.25) with atenolol treatment than with other active treatment, in the five studies comprising 17671 patients who were followed up for a mean of 4.6 years. The blood pressure lowering effect of atenolol is not less than that of other antihypertensive drugs. How could these results be explained? First, atenolol differs from other β blockers in its low lipophilic profile. Data from studies in animals suggest that the ability to prevent ventricular fibrillation depends on the amount of β blocker in the central nervous system. The hydrophilic atenolol has very low permeability into the nervous system. A previous meta-analysis of studies on β blockers after myocardial infarction showed that metoprolol, timolol, and propranolol significantly prevented death in the long term. Second, the effect of atenolol on left ventricular hypertrophy has not been systematically assessed in long term studies. The largest meta-analysis of the effect of different antihypertensive classes on left ventricular mass recently showed, however, that β blockers seemed to have less beneficial effect on regression of left ventricular hypertrophy than other drugs. Third, many antihypertensive drugs correct the remodelling and endothelial dysfunction of small arteries seen in hypertension, but this finding has not been seen for atenolol.
On-call or shift system: what is best for the patient? ▸
Thirty three years ago, Friedman and colleagues reported that interns made almost twice as many errors reading ECGs after an extended (24 hours or more) work shift than after a night of sleep. There is an increasing drive to reduce doctors’ hours. This is sometimes resisted by doctors who see a reduction in training, loss of continuity of care for the patient, and reduced pay as obstacles. To assess medical errors, interns (junior doctors) working on a medical high dependency unit and on coronary care units were randomly allocated to traditional very intensive on-call rotas, or a partial shift system (the intervention). During the intervention schedule, interns’ work hours and overnight work schedules were changed. Interns’ traditional extended work shifts were divided in two: a “day-call” intern worked the first half of a traditional call (from 7 am to 10 pm); a “night-call” intern worked the second half (from 9 pm to 1 pm the following day). The maximal scheduled hours of work were 60 to 63 per week, with consecutive hours of work limited to approximately 16 hours. This is still not compliant with the European Working Time Directive. Interns made 20.8% more serious medication errors during the traditional schedule than during the intervention schedule (99.7 v 82.5 per 1000 patient-days, p = 0.03). Interns made 5.6 times as many serious diagnostic errors during the traditional schedule as during the intervention schedule (18.6 v 3.3 per 1000 patient-days, p < 0.001). The rates of serious procedural errors among interns did not differ significantly between the two schedules. Most errors were spotted by other staff. Having interns on a different schedule than supervising residents may have introduced discontinuities in education and interfered with the traditional resident–intern mentorship bond. This could be looked at in future research.
Heart surgery in small children: use reconstituted blood ▸
In a single centre, randomised, double blind, controlled trial involving children younger than 1 year old who underwent open heart surgery, patients were assigned to receive either fresh whole blood that had been collected not more than 48 hours previously (96 patients) or reconstituted blood (104 patients) for bypass circuit priming. Clinical outcomes and serologic measures of systemic inflammation and myocardial injury were compared between the groups. The group that received reconstituted blood had a shorter stay in the intensive care unit than the group that received fresh whole blood (70.5 hours v 97.0 hours, p = 0.04). The group that received reconstituted blood also had a smaller cumulative fluid balance at 48 hours (–6.9 ml/kg of body weight v 28.8 ml/kg, p = 0.003). Early postoperative chest tube output, blood product transfusion requirements, and concentrations of serum mediators of inflammation and cardiac troponin I were similar in the two groups.
American Journal of Medicine; American Journal of Physiology: Heart and Circulatory Physiology; Annals of Emergency Medicine; Annals of Thoracic Surgery; Archives of Internal Medicine; BMJ; Chest; European Journal of Cardiothoracic Surgery; Lancet; JAMA; Journal of Clinical Investigation; Journal of Diabetes and its Complications; Journal of Immunology; Journal of Thoracic and Cardiovascular Surgery; Nature Medicine; New England Journal of Medicine; Pharmacoeconomics; Thorax
Dr Diana Gorog, Dr Akhil Kapur, Dr Masood Khan, Dr Alistair Lindsay, Dr Andrew Sharp
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