Hospital volume of throughput and periprocedural and medium-term adverse events after percutaneous coronary intervention: retrospective cohort study of all 17,417 procedures undertaken in Scotland, 1997-2003.

OBJECTIVE: To determine whether percutaneous coronary intervention (PCI) hospital volume of throughput is associated with periprocedural and medium-term events, and whether any associations are independent of differences in case mix. DESIGN: Retrospective cohort study of all PCIs undertaken in Scottish National Health Service hospitals over a six-year period. METHODS: All PCIs in Scotland during 1997-2003 were examined. Linkage to administrative databases identified events over two years' follow up. The risk of events by hospital volume at 30 days and two years was compared by using logistic regression and Cox proportional hazards models. RESULTS: Of the 17,417 PCIs, 4900 (28%) were in low-volume hospitals and 3242 (19%) in high-volume hospitals. After adjustment for case mix, there were no significant differences in risk of death or myocardial infarction. Patients treated in high-volume hospitals were less likely to require emergency surgery (adjusted odds ratio 0.18, 95% confidence interval (CI) 0.07 to 0.54, p = 0.002). Over two years, patients in high-volume hospitals were less likely to undergo surgery (adjusted hazard ratio 0.52, 95% CI 0.35 to 0.75, p = 0.001), but this was offset by an increased likelihood of further PCI. There was no net difference in coronary revascularisation or in overall events. CONCLUSION: Death and myocardial infarction were infrequent complications of PCI and did not differ significantly by volume. Emergency surgery was less common in high-volume hospitals. Over two years, patients treated in high-volume centres were as likely to undergo some form of revascularisation but less likely to undergo surgery.

Reducing call-to-needle times: the critical role of pre-hospital thrombolysis.

BACKGROUND: Current guidelines recommend that patients with acute myocardial infarction should receive thrombolysis within 60 min of seeking professional help. AIM: To compare current rates of pre-hospital thrombolysis in Grampian with historical data, and assess the effect of pre-hospital thrombolysis on the proportion of patients achieving 'call-to-needle' times within national guidelines. DESIGN: Prospective audit. METHODS: Data were collected on all patients (n=535) admitted to the coronary care unit and thrombolysed, either in hospital or in the community from July 2000 to June 2002, using standardized forms. RESULTS: One hundred and thirty-three patients (25%) received pre-hospital thrombolysis and 402 (75%) received in-hospital thrombolysis. This compares with a 19% (195/1046) pre-hospital thrombolysis rate in the mid-1990s (p=0.005). Median 'call-to-needle' times were 45 min for pre-hospital thrombolysis and 105 min for patients who received in-hospital thrombolysis (p < 0.001). Only 24% (96/396) of patients receiving in-hospital thrombolysis were treated within the recommended guideline, vs. 79% (88/111) of pre-hospital thrombolysis patients (p <0.001). DISCUSSION: Pre-hospital thrombolysis rates in Grampian are increasing. Administration of thrombolysis in the community greatly increases the proportion of patients achieving a 'call-to-needle' time of 60 min, with a median time saving of approximately 1 h.

'Rescue' after failed thrombolysis for acute myocardial infarction.

Prompt restoration of coronary artery patency in acute myocardial infarction is associated with substantial improvements in morbidity and mortality. The pivotal role of thrombolysis and aspirin in achieving these goals is well established. However, despite the success of thrombolytic therapy in large trials, clinical assessment in individual patients often suggests that reperfusion has not occurred after initial therapy. This review considers the validity of such bedside predictions and discusses whether such patients should be managed differently.

Risk stratification after myocardial infarction in Scotland.

The objective was to determine how patients are selected for invasive investigation after myocardial infarction in Scotland. Cardiologists in Scotland were surveyed by postal questionnaire asking them to detail their approach to four sample clinical scenarios. Complete responses were obtained from 82% of those surveyed. Substantial differences in practice were observed in the management of subjects with non-Q wave myocardial infarction. Of the cardiologists surveyed 40% would undertake coronary angiography irrespective of the results of non-invasive testing in a 45 year old patient, but only one would adopt the same policy in an otherwise fit 77 year old. Only 44% would perform any investigations (beyond echocardiography) in the 77 year old. A minority of respondents felt that their practice was influenced by resource limitation. Considerable variation continues to exist in the approach to risk stratification after myocardial infarction for some groups of patients. This variation may occur principally as a consequence of physician preference.

Respiratory arrest during dipyridamole stress testing.

There is an increasing usage of radionuclide scanning to assess myocardial perfusion, with dipyridamole, the most commonly used stress agent. Although this is an effective, and usually very safe, means by which to assess myocardial blood supply, there have been several incidents of acute bronchospasm in asthmatic patients. There have, however, been no previous reports of respiratory arrest occurring in patients with emphysema. This case illustrates the dangers of administering intravenous dipyridamole, or even adenosine, to patients with chronic lung disease.

Changing patterns of investigation and treatment of cardiac failure in hospital.

OBJECTIVE: To assess the investigation and treatment of cardiac failure in 1995 and to compare this with management in 1992. DESIGN: Retrospective consecutive case study. SETTING: University teaching hospital. SUBJECTS: All patients (n = 265) discharged from Aberdeen Royal Infirmary in the first quarter (January 1-31 March) of 1995 with a diagnosis of congestive cardiac failure, left ventricular failure, or heart failure (unspecified). These correspond to the International Classification of Diseases 9th revision codings of 428.0, 428.1, and 428.9 respectively. METHODS: Sociodemographic and clinical data were extracted from the case notes of the above subjects and compared with similar data from the final six months of 1992. MAIN OUTCOME MEASURES: The use of echocardiography in confirming the diagnosis and delineating the aetiology of heart failure and the use of angiotensin-converting enzyme (ACE) inhibitors in the treatment of patients diagnosed as having heart failure and without contraindications to these agents. RESULTS: The number of patients discharged in 1995 with a diagnosis including cardiac failure had increased by 55.7% since 1992. The use of echocardiography had also risen from 36.6% to 72% (P < 0.0001) with an associated increase in the proportion of patients discharged on treatment with an ACE inhibitor (40% in 1992 v 55.1% in 1995: P < 0.001). The doses of ACE inhibitors used had also increased significantly (P < 0.001). Most patients with cardiac failure continue to be treated by general physicians, who are less likely to use echocardiography (P < 0.01) or prescribe an ACE inhibitor (P < 0.05) than cardiologists. CONCLUSIONS: There is increasing recognition, more thorough investigation, and improved treatment of heart failure. Despite this there are grounds for concern, both in terms of the adequacy of management and resource implications.

Angiotensin-converting-enzyme inhibitors in the management of cardiac failure: are we ignoring the evidence?

The benefits of angiotensin-converting enzyme (ACE) inhibition in the management of cardiac failure have been extensively documented. However, little is known about its impact upon the investigation and management of this condition. We assessed how patients diagnosed as having cardiac failure were investigated, which patients were treated with ACE inhibitors and with what dosages. We reviewed the case notes of all 343 patients discharged from Aberdeen Royal Infirmary 1 July-31 December 1992 with a diagnosis of cardiac failure. In addition, a questionnaire was sent to the general practitioners of the 166 patients still alive in October 1994. Only 40% of patients were discharged from hospital on ACE inhibitors. In 58.8%, the diagnosis of cardiac failure was based purely on clinical or radiological grounds. At discharge, 76.1% of patients were on lower doses of ACE inhibitors than those used in the major survival studies; with 68.9% receiving similar doses two years later. The majority of patients with heart failure are under-investigated and under-treated.

The risks of thrombolysis in patients without acute myocardial infarction.

The risk of administering thrombolysis to patients with suspected myocardial infarction who subsequently do not sustain an infarct, but develop complications associated with thrombolysis is of concern to all physicians. The objective of this study was to ascertain the effect of altering the criteria for the administration of thrombolysis on the number of patients who received thrombolysis in the absence of infarction. During 1990 and 1992 details of all admissions with chest pain were recorded. During 1991 the policy for the administration of thrombolysis was altered so that only patients with ST elevation were eligible. A total of 1473 patients were admitted with chest pain in 1990 and 1967 in 1992. Of the patients admitted in 1990, 663 (45%) had confirmed infarction of whom 378 (57.0%) received thrombolysis. In 1992, 855 (43%) were admitted with infarction and of these 450 (52.6%) had thrombolytic therapy. 118 patients had no evidence of myocardial infarction, but received thrombolysis. 91 (77.1%) were admitted in 1990 and 27 (22.9%) in 1992 (P < 0.01). Of these only 24 (20%) subjects had ST elevation or bundle branch block on the admission electrocardiograph and 41 (35%) had normal tracings. Four (3%) subjects had serious complications of whom one (0.8%) died. The implementation of ECG criteria resulted in a significant reduction in the number of patients without infarction who received thrombolysis, but did not significantly alter the rate of thrombolysis in those with definite myocardial infarction.

Delay between the onset of symptoms of acute myocardial infarction and seeking medical assistance is influenced by left ventricular function at presentation.

OBJECTIVE: To determine whether the interval between the onset of symptoms of acute myocardial infarction and the patient's call for medical assistance (patient delay) is related to left ventricular function at the time of presentation. DESIGN: Prospective observational study. SETTING: Coronary care unit of Aberdeen Royal Infirmary. PATIENTS: 93 consecutive patients with acute myocardial infarction. MAIN OUTCOME MEASURES: Left ventricular stroke distance, expressed as a percentage of the age predicted normal value, measured first on admission, and then daily for 10 days or until discharge. Patients were questioned at admission to determine the time of onset of symptoms and the time of their call for medical assistance. RESULTS: Median (range) patient delay was 30 (1-360) min. Mean (SD) stroke distance on admission was 70(18)%, rising to 77(19)% on the second recording, and to 84(18)% on the day of discharge. Linear regression of log(e)(patient delay) against first, second, and last measurements of stroke distance gave correlation coefficients of 0.28 (P < 0.01), 0.18 (not significant), and 0.11 (not significant), respectively. CONCLUSIONS: Patient delay within the first 4 h after the onset of symptoms of acute myocardial infarction is positively related to left ventricular function on admission. A possible explanation is that deteriorating left ventricular function influences the patient's decision to call for help. This tendency for patients with more severe infarction to call for help sooner is an added reason for giving thrombolytic treatment at the first opportunity: those who call early have most to gain from prompt management.

Women and myocardial infarction: agism rather than sexism?

OBJECTIVE: To determine whether women with myocardial infarction are treated differently from men of the same age and to assess the effect of changes in the coronary care unit admission policy. DESIGN: Clinical audit. SETTING: The coronary care unit and general medical wards of a teaching hospital. In 1990 the age limit for admission to coronary care was 65 years. This age limit was removed in 1991. PATIENTS: 539 female and 977 male patients admitted with myocardial infarction between 1990 and 1992. MAIN OUTCOMES: Admission to the coronary care unit, administration of thrombolysis, and in-hospital mortality. RESULTS: 409 men and 254 women were admitted with myocardial infarction in 1990 and 568 men and 285 women in 1992. Removal of the age limit for admission to the coronary care unit resulted in an increase in the numbers of both sexes admitted with myocardial infarction. In both years, however, proportionately more men with infarction were admitted to coronary care: 226 men (55%) and 96 women (38%) (P < 0.01) (95% CI 7 to 28) in 1990 and 459 men (81%) and 200 women (70%) (P < 0.01) (%CI 2 to 19) in 1992. Some 246 men (60%) and 133 women (52%) with infarction (P < 0.01) received thrombolytic treatment in 1990 compared with 319 men (56%) and 130 women (46%) (P < 0.01) in 1992. The mean age of women sustaining a myocardial infarction was significantly greater in both years studied. In 1992 a total of 78 men (7%) and 34 women (4%) (P < 0.05) admitted with chest pain underwent cardiac catheterisation before discharge from hospital. CONCLUSIONS: Differences in admission rates to the coronary care unit and the rate of thrombolysis between the sexes can be explained by the older age of women sustaining infarction. The application of age limits for admission to coronary care or administration of thrombolysis places elderly patients at a disadvantage. As women sustain myocardial infarctions at an older age they are placed at a greater disadvantage.

Patients with suspected myocardial infarction who present with ST depression.

Patients with suspected myocardial infarction who present with ST depression have a high mortality which is not reduced by thrombolytic therapy. Despite this, there are few data on these patients. We studied the electrocardiographic and clinical characteristics of these patients, the diagnostic and prognostic value of the presenting electrocardiogram (ECG), and the reasons for the high mortality and apparent lack of thrombolytic efficacy. We studied all patients with suspected infarction admitted during 1990 with ST depression. Of the 136 patients (84 men, mean [SD] age 68 [11] years), 74 (54%) had confirmed infarction and 73 (54%) had previous infarction. 1-year mortality was 26% for all patients, 31% for those with confirmed infarcts, and 19% for those in whom infarction was subsequently excluded. Patients with infarction had more severe ST depression (mean 2.5 mm [SD 1.5]) and more ECG leads with ST depression (mean 4.7 leads [1.8]) compared with patients without infarction (1.4 mm [0.8], p < 0.001; 3.6 leads [1.7], p < 0.001). Sensitivity and specificity for the subsequent diagnosis of infarction with ST depression were 20% and 97%, respectively, for at least 4 mm; and 21% and 95%, respectively, for at least 7 leads. 1-year mortality was low in patients with 1 mm ST depression (14%) or no more than 2 leads (11%), but high in patients with at least 2 mm ST depression (39%, p < 0.001) and at least 3 leads (30%, p = 0.08). Patients with suspected infarction and ST depression had a high mean age, high incidence of previous infarction, and poor prognosis. The presenting ECG is helpful in predicting prognosis, and ST depression of at least 4 mm or involving at least 7 leads is highly specific for diagnosis of infarction.

Inter- and intra-observer variability in detection of patent foramen ovale with contrast echocardiography.

Patent foramen ovale is detected in-vivo using the technique of contrast echocardiography. A positive test depends on the ability of an observer to recognise micro-bubbles passing from the right to the left heart, and to differentiate them from background noise and/or chordae tendinae. To assess the inter- and intra-observer variability of this technique four observers reviewed independently, and on two separate occasions, 100 consecutive contrast studies stored on video tape. The proportions of agreement (95% CI) for each separate observer on the two occasions for the presence of patent foramen ovale were 0.91 (0.76-0.98), 0.88 (0.73-0.92), 0.80 (0.63-0.92) and 0.78 (0.60-0.91), and for its absence were 0.96 (0.88-0.99), 0.95 (0.87-0.99), 0.90 (0.81-0.96) and 0.91 (0.82-0.96), respectively. The proportions of agreement (95% CI) between all observers on the first viewing were 0.78 (0.72-0.84) for the presence and 0.91 (0.87-0.93) for the absence of patent foramen ovale. For the second viewing these were 0.81 (0.75-0.86) and 0.91 (0.88-0.94), respectively (P = NS, Chi-squared test). These results indicate that contrast echocardiography is subject to clinically acceptable inter- and intra-observer variability.

Coronary artery ectasia: is it associated with myocardial ischaemia and infarction?

Coronary artery ectasia is an uncommon finding during coronary angiography. There may be associated stenoses of the affected arteries. We report three cases, which illustrate that ectasia, in the absence of obstructive disease, can result in myocardial ischaemia and infarction.

Two coronary artery fistulae in a patient with temporal arteritis and chest pain.

A 59-year-old woman with a history of cardiac sounding chest pain was investigated by coronary arteriography. Two unsuspected fistulae were found. The fistulae originated from the distal right coronary artery and the diagonal branch of the left coronary artery. Both drained into the left ventricle. She was also found to have temporal arteritis, treatment of which abolished the chest pain.