How well does standard clinician evaluation identify low likelihood of ischaemic or coronary heart disease?

Guidelines claim that patients with a low likelihood of coronary artery disease can be reliably identified clinically by a simple set of rules. Among 385 patients referred for coronary angiography because of suspected stable angina pectoris we found by myocardial perfusion scintigraphy in three selected low likelihood groups reversible perfusion defects in 23%-29% of male and 11%-17% of female patients. Rates of significant angiographic disease were similar. These data question the validity of current clinical practice for identifying low likelihood of disease in this category of patients.

High probability of disease in angina pectoris patients: is clinical estimation reliable?

BACKGROUND: According to most current guidelines, stable angina pectoris patients with a high probability of having coronary artery disease can be reliably identified clinically. OBJECTIVES: To examine the reliability of clinical evaluation with or without an at-rest electrocardiogram (ECG) in patients with a high probability of coronary artery disease. PATIENTS AND METHODS: A prospective series of 357 patients referred for coronary angiography (CA) for suspected stable angina pectoris were examined by a trained physician who judged their type of pain and Canadian Cardiovascular Society grade of pain. Pretest likelihood of disease was estimated, and all patients underwent myocardial perfusion scintigraphy (MPS) followed by CA an average of 78 days later. For analysis, the investigators focused on the approximate groups of patients with more severe disease, ie, typical angina (n=187), Canadian Cardiovascular Society grade 2 pain or higher (n=176) or high (higher than 85%) estimated pretest likelihood of disease (n=142). RESULTS: In the three groups, 34% to 39% of male patients and 65% to 69% of female patients had normal MPS, while 37% to 38% and 60% to 71%, respectively, had insignificant findings on CA. Of the patients who had also an abnormal at-rest ECG, 14% to 21% of men and 42% to 57% of women had normal MPS. Sex-related differences were statistically significant. CONCLUSIONS: Clinical prediction appears to be unreliable. Addition of at-rest ECG data results in some improvement, particularly in male patients, but it makes the high probability groups so small that the addition appears to be of limited clinical relevance.

To what degree is amelioration of angina following coronary revascularization associated with improvement in myocardial perfusion?

OBJECTIVE: To examine the association between changes in chest pain and changes in perfusion following revascularization as assessed by clinical evaluation and myocardial perfusion imaging (MPI) in patients with stable angina. DESIGN: In a prospective series of 380 patients (58.8 +/- 8.8 years) referred to angiography because of known or suspected stable angina, changes in chest discomfort and changes in perfusion after 2 years were assessed in 144 patients, who underwent revascularization, and 236, who did not. The decision to treat invasively was made without knowledge of the result of MPI. RESULTS: In revascularized patients, the presence of typical/atypical angina was reduced from 93% to 36% and the improvement was associated with improvement in perfusion. A small improvement in perfusion induced a high frequency of change from angina to no pain, whereas a further reduction caused little extra change. In non-revascularized patients the change in chest discomfort was not related to changes in perfusion, which were rarely present. CONCLUSION: Alleviation of chest discomfort 2 years after revascularization is associated with improvements in perfusion. This association appeared to be an all-or-nothing phenomenon. Non-revascularized patients also exhibited improvements in chest discomfort despite insignificant changes in perfusion.

Prognostic value of myocardial perfusion imaging in patients with known or suspected stable angina pectoris: evaluation in a setting in which myocardial perfusion imaging did not influence the choice of treatment.

OBJECTIVE: Previous investigations on the prognostic value of myocardial perfusion imaging (MPI) were performed under circumstances in which the test result was known to the patient's physician. We wanted to examine the prognostic value of MPI in patients with known or suspected stable angina in a setting in which MPI could not influence the diagnostic and therapeutic strategy. DESIGN: A prospective series of 507 patients referred to coronary angiography for this condition were examined by MPI before angiography. Management was based on symptoms and angiographic findings, as the results of MPI were not communicated. Patients were followed for a mean of 45.3 +/- 7.7 months. RESULTS: During follow-up, 20 patients (3.9%) suffered from myocardial infarction, 19 (3.8%) died and eight (1.6%) were revascularized >1 year after MPI resulting in a combined annual event rate of 2.5%. Patients with normal MPI had a low annual event rate of 1.6% (or 1.1% with regard to myocardial infarction or death only). In contrast, event rates in patients with reversible or mixed ischaemia were 4.0% per year. MPI added independent prognostic value to standard clinical data in a multivariate Cox model. CONCLUSION: We could confirm that in patients with known or suspected stable angina, MPI is a valuable risk stratifying tool.

[Quality improvement of referrals from practising physicians. An example of a practicable strategy]. / Kvalitetsforbedring af henvisninger fra praksissektoren. Et eksempel på en brugbar strategi.

INTRODUCTION: Referrals from practising physicians to hospital departments are of varying quality. This increases the risk of inappropriate or even incorrect patient treatment courses. We examined the quality of referrals to a large department of nuclear medicine before and after initiatives aimed at improving the information and feedback to the practising physicians. MATERIALS AND METHODS: An evaluation of the quality of referrals (n = 579) from praticising physicians to the Department of Nuclear Medicine, Odense University Hospital, Denmark, recorded during two periods of three months each before and after (1) publication of a referral guideline and (2) a feedback response to those physicians whose referrals were insufficient. A general practitioner (GP) and a specialist in nuclear medicine (NM) judged independently whether the referrals were good, acceptable or unacceptable. RESULTS: During the two periods, 281 and 298 referrals were received, respectively. Of these, 37% and 27%, respectively, were from practising specialists (PSs). After intervention, 23% more referrals were received from GPs, and the share of "good" referrals also increased (before/after: 48%/72% (GP), 61%/84% (NM)). In contrast, there was a 23% decrease in referrals from PSs, whereas the share of "good" referrals remained unchanged or increased (before/after: 64%/66 % (GP), 64%/96% (NM)). In addition, there was a change in the referral pattern from both GPs and PSs. CONCLUSION: Relatively simple and inexpensive intervention caused an increase in the number and quality of referrals from GPs and a fall in referrals from PSs without an obvious improvement in quality.

[Quality control of whole-body bone scintigraphy. Patient surveys]. / Kvalitetsudvikling af helkropsknogleskintigrafi. Patientundersøgelser.

INTRODUCTION: The quality of health care is but sparsely elucidated; surveys of complete patient courses hardly exist. We established and used benchmarks for a major nuclear medicine examination: whole-body bone scintigraphy. MATERIALS AND METHODS: The study material included 458 out of 512 consecutive examinations. Patients were referred by general practitioners (12%), practising specialists (16%) and hospital departments (72%). The survey dealt with waiting times and information provided, as judged by the patient, the referring physician and the Department of Nuclear Medicine (DNM) in relation to referrals, reporting and the passing on of the results to the patient. The DNM judged the quality of the examinations, and the referring physician assessed the implications for diagnosis and treatment. RESULTS: In 10% of the cases, the patient felt that the waiting time was unsatisfactory, as the referring physician might take up to 150 days to send the referral and because 11% had, after two months, still not been informed of the examination result. Supplementary tomography was used in 38 examinations (8%); of these, only one (3%) provided new evidence. Based on the examination results, the referring physician could make a diagnosis and/or wanted to change management for 61% of patients. CONCLUSION: Referrals were delayed mainly by the referring physicians, who often forgot to inform their patients of the examination results. Special admissions seldom yielded extra information. The examination result had important clinical implications in almost two thirds of patients.

Redefinition of the Q wave -- is there a clinical problem?

This study evaluated the potential consequences of the redefined joint European/American electrocardiographic criteria for an established myocardial infarction (MI). New and previous diagnostic Q-wave criteria were used in patients with stable angina pectoris. Seventy-nine patients with and 77 patients without a documented previous MI were compared using the results of myocardial perfusion imaging at rest as a reference. With the new Q-wave criteria, 71% of the former group and 40% of the latter had evidence of established MI compared with 33% and 3% when using the previous criteria (p <0.0001). Sensitivity, specificity, and positive and negative predictive values were 71%, 60%, 64%, and 67% for the new criteria versus 33%, 97%, 93%, and 59% with the previous criteria. These data suggest that that the new Q-wave criteria may be too nonspecific, resulting in an inappropriately high number of false-positive results.

[The value of myocardial perfusion scintigraphy as a "gatekeeper" for coronary angiography and revascularisation in patients with stable angina pectoris--a secondary publication]. / Vaerdien af myokardieskintigrafi som gatekeeper for koronararteriografi og revaskularisering hos patienter med stabil angina pectoris--sekundaerpublikation.

In 507 out of a series of 972 patients referred consecutively to coronary angiography (CA) for stable angina pectoris, preceding "blinded" myocardial perfusion scintigraphy (MPS) demonstrated normal perfusion in 51%, reversible defects in 40%, and fixed defects in 9% of patients. CA showed insignificant findings in 49% and in 41% of the entire series. Of 168 revascularised patients, no more than 74% had reversible perfusion defects with MPS. On this basis it could be estimated that almost half of catheterizations and nearly one fifth of revascularisations were "superfluous".

Potential impact of myocardial perfusion scintigraphy as gatekeeper for invasive examination and treatment in patients with stable angina pectoris: observational study without post-test referral bias.

AIMS: To evaluate the impact of using myocardial perfusion scintigraphy (MPS) as gatekeeper for coronary angiography and revascularization in stable angina pectoris. METHODS AND RESULTS: A prospective series of 507 out of 972 adult patients referred to coronary angiography for known or suspected stable angina pectoris underwent clinical examination followed immediately by MPS, the result of which was not communicated. MPS showed normal perfusion in 258/507 (51%) patients, reversible defects in 201/507 (40%), and fixed defects in 48/507 (9%). Of 168 revascularized patients, 27 (16%) had normal perfusion and 13 (8%) had fixed defects. Coronary angiography was undertaken in 476 patients of whom 252 (53%) had normal findings or insignificant stenoses. The same was the case in 361 (41%) out of the 883 of the 972 consecutive patients, who had this examination. Assuming that the true rate of normal perfusion in the entire series was correspondingly lower, 48% of catheterizations and 19% of revascularizations were superfluous. CONCLUSION: The use of MPS as gatekeeper appears to make about half of catheterizations and almost one-fifth of revascularizations redundant. Even in high-risk groups, substantial savings are possible, and the risk of overlooking patients with severe disease seems negligible.

Use of myocardial perfusion imaging to predict the effectiveness of coronary revascularisation in patients with stable angina pectoris.

PURPOSE: Coronary revascularisation is the treatment of choice in patients with stable angina who have significant stenoses. From a pathophysiological point of view, however, mitigation of angina is to be expected only in the presence of reversible ischaemia. Therefore it was the aim of this study to examine the effect of revascularisation on stable angina in relation to the myocardial perfusion imaging (MPI) pattern prior to intervention. METHODS: Three hundred and eighty-four patients (58.0+/-8.8 years) referred for angiography underwent MPI. Prior to MPI and at 2-year follow-up, patients were classified as having typical angina, atypical angina, non-cardiac chest pain or no pain, and the severity of chest pain was graded according to the Canadian Cardiovascular Society (CCS) criteria. The patients themselves estimated their pain on a visual analogue scale. Management was based on symptoms and angiographic findings, since the results of MPI were not communicated. RESULTS: Among the 240 patients who were not revascularised, 79% had typical or atypical angina at study entrance versus 40% at follow-up. In comparison, 93% of the 144 revascularised patients had typical or atypical angina before intervention versus only 36% at follow-up. This additional advantage of invasive therapy was present only in patients with reversible defects; revascularisation had no additional effect in patients with normal perfusion or irreversible defects. Similarly, additional, significant reductions in CCS class and visual analogue score were observed exclusively in patients with reversible defects. CONCLUSION: In patients referred for coronary angiography owing to known or suspected stable angina, revascularisation was significantly more effective than medical treatment exclusively in patients with reversible ischaemia.