The diagnosis of heart failure in general practice: implications for the UK National Service Framework

Clinical Influence of Handheld Ultrasound, Supported by Automatic Quantification and Telemedicine, in Suspected Heart Failure

Early and correct heart failure (HF) diagnosis is essential to improvement of patient care. We aimed to evaluate the clinical influence of handheld ultrasound device (HUD) examinations by general practitioners (GPs) in patients with suspected HF with or without the use of automatic measurement of left ventricular (LV) ejection fraction (autoEF), mitral annular plane systolic excursion (autoMAPSE) and telemedical support. Five GPs with limited ultrasound experience examined 166 patients with suspected HF (median interquartile range = 70 (63-78) y; mean ± SD EF = 53 ± 10%). They first performed a clinical examination. Second, they added an examination with HUD, automatic quantification tools and, finally, telemedical support by an external cardiologist. At all stages, the GPs considered whether the patients had HF. The final diagnosis was made by one of five cardiologists using medical history and clinical evaluation including a standard echocardiography. Compared with the cardiologists' decision, the GPs correctly classified 54% by clinical evaluation. The proportion increased to 71% after adding HUDs, and to 74 % after telemedical evaluation. Net reclassification improvement was highest for HUD with telemedicine. There was no significant benefit of the automatic tools (p ≥ 0.58). Addition of HUD and telemedicine improved the GPs' diagnostic precision in suspected HF. Automatic LV quantification added no benefit. Refined algorithms and more training may be needed before inexperienced users benefit from automatic quantification of cardiac function by HUDs.

Evidence for models of diagnostic service provision in the community: literature mapping exercise and focused rapid reviews

Background

Current NHS policy favours the expansion of diagnostic testing services in community and primary care settings.

Objectives

Our objectives were to identify current models of community diagnostic services in the UK and internationally and to assess the evidence for quality, safety and clinical effectiveness of such services. We were also interested in whether or not there is any evidence to support a broader range of diagnostic tests being provided in the community.

Review methods

We performed an initial broad literature mapping exercise to assess the quantity and nature of the published research evidence. The results were used to inform selection of three areas for investigation in more detail. We chose to perform focused reviews on logistics of diagnostic modalities in primary care (because the relevant issues differ widely between different types of test); diagnostic ultrasound (a key diagnostic technology affected by developments in equipment); and a diagnostic pathway (assessment of breathlessness) typically delivered wholly or partly in primary care/community settings. Databases and other sources searched, and search dates, were decided individually for each review. Quantitative and qualitative systematic reviews and primary studies of any design were eligible for inclusion.

Results

We identified seven main models of service that are delivered in primary care/community settings and in most cases with the possible involvement of community/primary care staff. Not all of these models are relevant to all types of diagnostic test. Overall, the evidence base for community- and primary care-based diagnostic services was limited, with very few controlled studies comparing different models of service. We found evidence from different settings that these services can reduce referrals to secondary care and allow more patients to be managed in primary care, but the quality of the research was generally poor. Evidence on the quality (including diagnostic accuracy and appropriateness of test ordering) and safety of such services was mixed.

Conclusions

In the absence of clear evidence of superior clinical effectiveness and cost-effectiveness, the expansion of community-based services appears to be driven by other factors. These include policies to encourage moving services out of hospitals; the promise of reduced waiting times for diagnosis; the availability of a wider range of suitable tests and/or cheaper, more user-friendly equipment; and the ability of commercial providers to bid for NHS contracts. However, service development also faces a number of barriers, including issues related to staffing, training, governance and quality control.

Limitations

We have not attempted to cover all types of diagnostic technology in equal depth. Time and staff resources constrained our ability to carry out review processes in duplicate. Research in this field is limited by the difficulty of obtaining, from publicly available sources, up-to-date information about what models of service are commissioned, where and from which providers.

Future work

There is a need for research to compare the outcomes of different service models using robust study designs. Comparisons of ‘true’ community-based services with secondary care-based open-access services and rapid access clinics would be particularly valuable. There are specific needs for economic evaluations and for studies that incorporate effects on the wider health system. There appears to be no easy way of identifying what services are being commissioned from whom and keeping up with local evaluations of new services, suggesting a need to improve the availability of information in this area.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Trends in co-prescribing of angiotensin converting enzyme inhibitors and angiotensin receptor blockers in Ireland

AIMS

(i) To examine the trends in co-prescribing of angiotensin converting enzyme inhibitor (ACEI) and angiotensin-II receptor blocker (ARB) therapy and (ii) to examine the influence of major clinical trials (CALM, COOPERATE, VALIANT and ONTARGET) on co-prescribing.

METHODS

The Irish HSE-Primary Care Reimbursement Services database was used to identify patients ≥16 years old co-prescribed ACEIs and ARBs between January 2000 and April 2009 (n= 266 554 prescriptions). The rate of prescribing per 1000 general medical services (GMS) scheme population was calculated for each month. Patients with diabetes, hypertension, heart failure and ischaemic heart disease were also identified by prescribing of certain medications. A linear trend test was used to examine prescribing trends. Logistic regression was used to examine prescribing according to patient characteristics. The effects of the major trials on prescribing were examined using segmented regression analysis for 12 months pre- and post-trials.

RESULTS

There was a significant linear trend in overall ACEI and ARB co-prescribing over the study period (P < 0.001). Rate of co-prescribing in January 2000 and April 2009 was 0.16 and 5.72, per 1000 eligible population, respectively. Those 45-64 years old (OR = 2.88, 95% confidence interval (CI) 2.71, 3.06) and ≥65 years (OR = 2.52, 95% CI 2.36, 2.68) were more likely to receive dual therapy compared with those <45 years old. Those with hypertension (OR = 8.85, 95% CI 8.45, 9.27), diabetes (OR = 4.10, 95% CI 3.97, 4.23) and heart failure (OR = 1.78, 95% CI 1.72, 1.84) were more likely to receive dual therapy compared with the general population. Significant increases in prescribing were observed only after the CALM (P= 0.03) and VALIANT (P= 0.007) trials.

CONCLUSION

Increased co-prescribing of ACEIs and ARBs was observed in Ireland during 2000-09. Prescribing patterns did not appear to be affected by results from major trials.

The accuracy of symptoms, signs and diagnostic tests in the diagnosis of left ventricular dysfunction in primary care: a diagnostic accuracy systematic review

BACKGROUND

To assess the accuracy of findings from the clinical history, symptoms, signs and diagnostic tests (ECG, CXR and natriuretic peptides) in relation to the diagnosis of left ventricular systolic dysfunction (LVSD) in a primary care setting.

METHODS

Diagnostic accuracy systematic review, we searched Medline (1966 to March 2008), EMBASE (1988 to March 2008), Central, Cochrane and ZETOC using a diagnostic accuracy search filter. We included cross-sectional or cohort studies that assess the diagnostic utility of clinical history, symptoms, signs and diagnostic tests, against a reference standard of echocardiography. We calculated pooled positive and negative likelihood ratios and assessed heterogeneity using the I2 index.

RESULTS

24 studies incorporating 10,710 patients were included. The median prevalence of LVSD was 29.9% (inter-quartile range 14% to 37%). No item from the clinical history or symptoms provided sufficient diagnostic information to "rule in" or "rule out" LVSD. Displaced apex beat shows a convincing diagnostic effect with a pooled positive likelihood ratio of 16.0 (8.2-30.9) but this finding occurs infrequently in patients. ECG was the most widely studied diagnostic test, the negative likelihood ratio ranging from 0.06 to 0.6. Natriuretic peptide results were strongly heterogeneous, with negative likelihood ratios ranging from 0.02 to 0.80.

CONCLUSION

Findings from the clinical history and examination are insufficient to "rule in" or "rule out" a diagnosis of LVSD in primary care settings. BNP and ECG measurement appear to have similar diagnostic utility and are most useful in "ruling out" LVSD with a normal test result when the probability of LVSD is in the intermediate range.

Evaluation of B-type natriuretic peptide for validation of a heart failure register in primary care

Background

Diagnosing heart failure and left ventricular systolic dysfunction is difficult on clinical grounds alone. We sought to determine the accuracy of a heart failure register in a single primary care practice, and to examine the usefulness of b-type (or brain) natriuretic peptide (BNP) assay for this purpose.

Methods

A register validation audit in a single general practice in the UK was carried out. Of 217 patients on the heart failure register, 56 of 61 patients who had not been previously investigated underwent 12-lead electrocardiography and echocardiography within the practice site. Plasma was obtained for BNP assay from 45 subjects, and its performance in identifying echocardiographic abnormalities consistent with heart failure was assessed by analysing area under receiver operator characteristic (ROC) curves.

Results

30/217 were found to have no evidence to suggest heart failure on notes review and were probably incorrectly coded. 70/112 who were previously investigated were confirmed to have heart failure. Of those not previously investigated, 24/56 (42.9%) who attended for the study had echocardiographic left ventricular systolic dysfunction. A further 8 (14.3%) had normal systolic function, but had left ventricular hypertrophy or significant valve disease. Overall, echocardiographic features consistent with heart failure were found in only 102/203 (50.2%). BNP was poor at discriminating those with and without systolic dysfunction (area under ROC curve 0.612), and those with and without any significant echocardiographic abnormality (area under ROC curve 0.723).

Conclusion

In this practice, half of the registered patients did not have significant cardiac dysfunction. On-site echocardiography identifies patients who can be removed from the heart failure register. The use of BNP assay to determine which patients require echocardiography is not supported by these data.

Treatment patterns of hypertension and dyslipidaemia in hypertensive patients at higher and lower risk of cardiovascular disease in primary care in the United Kingdom

Few studies have investigated the presence of dyslipidaemia in hypertensive individuals. In addition, few data exist on the concurrent treatment of both conditions for the prevention of cardiovascular disease (CVD). This retrospective cohort study examined treatment patterns for hypertension and dyslipidaemia among hypertensive patients in UK primary care. We defined a population of patients aged > or =40 years from the UK General Practice Research Database. Hypertensive individuals with > or =3 additional cardiovascular risk factors (ARFs) were compared with a cohort comprising hypertensive patients with < or =2 ARFs. We analysed the prevalence of risk factors and the prevalence and incidence of treatment for hypertension, dyslipidaemia and for both conditions between January 1997 and December 2001. A total of 117 840 hypertensive patients were identified (23 655 with > or =3 ARFs, 94 185 with < or =2 ARFs) in 1997; in 2001, the number diagnosed as hypertensive was 133 683 (40 248 > or =3 ARFs, 93 435 < or =2 ARFs). The prevalence of antihypertensive treatment in the hypertensive patients with > or =3 ARFs increased during the study. In 2001, approximately one-third of hypertensive patients with > or =3 ARFs were not receiving antihypertensives. Among those patients who received such treatment, the majority received > or =2 separate agents in accordance with current guidelines. Treatment for concurrent hypertension and dyslipidaemia was initiated in <8% of patients with hypertension and > or =3 ARFs in each year. These findings demonstrate the under-recognition/undertreatment of cardiovascular risk factors in UK primary care among patients at risk of CVD.

Rapid brain natriuretic peptide test and Doppler echocardiography for early diagnosis of mild heart failure

BACKGROUND

The early identification of patients at risk for the development of clinical heart failure (HF) is a new challenge in an effort to improve outcomes.

METHODS

We prospectively evaluated whether the combination of brain natriuretic peptide (BNP) measurements (Triage BNP test, Biosite Diagnostics) and echocardiography would effectively stratify patients with new symptoms in a cost-effective HF program aimed at early diagnosis of mild HF. A total of 252 patients were referred by 100 general practitioners.

RESULTS

Among the study population, the median BNP value was 78 ng/L (range, 5-1491 ng/L). BNP concentrations were lower among patients without heart disease [median 15 ng/L (range, 5-167 ng/L); n = 96] than among patients with confirmed HF [median, 165 ng/L (22-1491 ng/L); n = 157; Mann-Whitney U-test, 12.3; P <0.001]. Patients were grouped into diastolic dysfunction [BNP, 195 (223) ng/L], systolic dysfunction [BNP, 290 (394) ng/L], and both systolic and diastolic dysfunction [BNP, 776 (506) ng/L]. In this model, a cutoff value of 50 ng/L BNP increases the diagnostic accuracy in predicting mild HF, avoiding 41 echocardiograms per 100 patients studied, with a net saving of 14% of total costs.

CONCLUSIONS

Blood BNP concentrations, in a cost effective targeted screening, can play an important role in diagnosing mild HF and stratifying patients into risk groups of cardiac dysfunction.

Early diagnosis of congestive heart failure: clinical utility of B-type natriuretic peptide testing associated with Doppler echocardiography

OBJECTIVE

B-type natriuretic peptide (BNP) has emerged as an important diagnostic serum marker of congestive heart failure (CHF). The aim of this study was to evaluate whether BNP measurement associated with echocardiography could effectively stratify patients with new symptoms as part of a cost-effective heart failure programme based on cooperation between hospital cardiologists and primary care physicians.

METHODS

Patients were referred to the cardiology clinic by general practitioners in case of clinical suspect of CHF. All patients underwent clinical examination, transthoracic echocardiography and plasma determination of BNP. Systolic dysfunction was defined as a left ventricular ejection fraction < 45%; diastolic dysfunction was defined as a preserved systolic function with signs of diastolic impairment.

RESULTS

Three hundred and fifty-seven subjects were examined (50% males, mean age 73 years). BNP concentration was 469 +/- 505 pg/ml in the 240 patients diagnosed with CHF, compared with 43 +/- 105 pg/ml in the 117 patients without CHF (P = 0.001). CHF patients were grouped into those with diastolic dysfunction (n = 110; BNP 373 +/- 335 pg/ml), systolic dysfunction (n = 108; BNP 550 +/- 602 pg/ml), and both systolic and diastolic dysfunction (n = 22; BNP 919 +/- 604 pg/ml). At receiver operating characteristic analysis, the optimal BNP cut-off level for diagnosing CHF was 80 pg/ml (sensitivity 84%, specificity 91%). According to cost analysis, this cut-off level might provide a cost saving of 31% without affecting diagnostic accuracy.

CONCLUSIONS

In patients referred by general practitioners for suspected CHF, plasma BNP levels might help to stratify subjects into different groups of cardiac dysfunction.

Diagnosis of heart failure in primary care

Heart failure is becoming an increasing concern to healthcare worldwide. It is the only cardiovascular disorder that continues to increase in both prevalence and incidence, and as the population continues to age, it is expected that the prevalence of this disease will continue to rise. Guidelines on diagnosis and treatment of heart failure are to be met. Most patients with heart failure will present themselves in general practice. Therefore, the community management of heart failure has become increasingly important and the role of General Practitioners even more crucial. Improving the reliability of diagnosis in primary care is essential since determining the aetiology and stage of heart failure leads to different management choices to improve symptoms, quality of life and disease prognosis. Furthermore, early diagnosis is needed, when there may be no symptoms, since treatment can delay or reverse disease progression. Diagnostic methods may therefore need to encompass screening strategies, as well as symptomatic case identification, in the future. General Practitioners must make correct decisions regarding appropriate further investigation, treatment and referral. A correct diagnosis is the cornerstone leading to effective management. The aim of this paper is to review the role of symptoms and signs and diagnostic tests, such as, chest X-ray, ECG, natriuretic peptides and echocardiography, for diagnosing heart failure in the primary care setting. Improving diagnostic skills remains a continuous challenge for clinicians. Simple and reliable diagnostic procedures are crucial to comply with Guidelines and reduce healthcare utilisation and costs.

Utility of brain natriuretic peptide (BNP) measurement in cardiovascular disease

Cardiac failure is a prevalent and costly condition in Western society. The ageing of the population, together with current medical options which improve, rather than eradicate heart failure, lead to the projection that this problem will increase substantially in the foreseeable future. The availability of a simple test to assist the diagnosis and effective management of heart failure would greatly assist the clinical approach to this problem. This review examines the physiological basis for the measurement of natriuretic peptides as markers of the presence or risk of heart failure. It considers its use in the hospital and non-hospital setting and examines the cost-effectiveness of current assays. It is possible that in future natriuretic peptides may offer a form of treatment for heart failure, but this is beyond the scope of this review. Nevertheless, the review highlights the potential benefits of this group of tests in the management of heart failure.

Accuracy of B-type natriuretic peptide levels in the diagnosis of left ventricular dysfunction and heart failure: a systematic review

OBJECTIVES

To evaluate the accuracy of B-type natriuretic peptide levels (BNP) in the diagnosis of heart failure and left ventricular dysfunction.

DATA SOURCES

Electronic search in Medline, Embase, Cochrane Library and Medion database, and hand search of reference lists.

REVIEW METHODS

We have included published studies on the accuracy of BNP which had both sufficient information to construct the 2x2 diagnostic cross table and an appropriate spectrum of patients.

RESULTS

Fifty five studies (16,730 patients) were analyzed. The main determinants of diagnostic accuracy were the reference standard analyzed (clinical heart failure versus left ventricular dysfunction), and the methodological quality of the study. BNP levels were highly accurate for the diagnosis of clinical heart failure (diagnostic OR=41; 95% CI 23-74). The negative likelihood ratios were homogeneous, and useful for excluding the existence of heart failure (pooled negative likelihood ratio=0.11; 95% CI 0.08-0.16). The studies focused on the identification of left ventricular dysfunction were heterogeneous, with indications of publication bias, and showed less overall diagnostic accuracy than studies focused on heart failure.

CONCLUSIONS

BNP levels are useful for ruling out heart failure. The accuracy of BNP for identifying patients with systolic dysfunction is more limited.

Management of chronic heart failure: perceived needs of general practitioners in light of the new general medical services contract

BACKGROUND

Despite the existence of several chronic heart failure (CHF) guidelines the treatment of patients with CHF is suboptimal. The new general medical services (GMS) contract in primary care has only three specific performance indicators for patients with left ventricular dysfunction. The aim of this current questionnaire survey was to assess the views of general practitioners (GPs) on CHF treatments and services in light of the new GMS contract.

METHODS AND RESULTS

All local GPs (717) were sent a questionnaire. Fifty three per cent were returned. Forty five per cent of GPs had access to a community CHF nurse. Having read a national guideline (SIGN) and having the support of a CHF nurse did not seem to affect the knowledge of GPs in terms of perceived benefits of drug treatments. GPs with access to a specialist CHF nurse service attached more importance to it than those with no specialist nurse (p = 0.003).

CONCLUSIONS

Most GPs were aware of the existence of a national guideline but many had not read it. There was little or no difference in the knowledge level for various evidence based treatments between GPs who had or had not read the guideline suggesting that reading guidelines may not be a key factor in determining knowledge. Support for a specialist CHF nurse was higher among GPs who already had this service, suggesting that this service is valued. The new GMS contract may improve identification and diagnosis of patients with CHF but there is a danger that it may fall short of ensuring optimal treatment for patients with CHF.

Effect of body mass index on natriuretic peptide levels in patients with acute congestive heart failure: a ProBNP Investigation of Dyspnea in the Emergency Department (PRIDE) substudy

BACKGROUND

Obesity is associated with lower B-type natriuretic peptide (BNP) levels in healthy individuals and patients with chronic congestive heart failure (CHF). Neither the mechanism of natriuretic peptide suppression in the obese patient nor whether obesity affects natriuretic peptide levels among patients with acute CHF is known.

METHODS

The associations of amino-terminal pro-BNP (NT-proBNP), BNP, and body mass index (BMI) were examined in 204 subjects with acute CHF. Multivariable regression analyses were performed to identify factors independently related to NT-proBNP and BNP levels.

RESULTS

Across clinical strata of normal (<25 kg/m2), overweight (25-29.9 kg/m2), and obese (> or =30 kg/m2) patients, median NT-proBNP and BNP levels decreased with increasing BMI (both P values < .001). In multivariable analyses adjusting for covariates known to affect BNP levels, the inverse relationship between BMI and both NT-proBNP and BNP remained ( P < .05 for both). Using a cut point of 900 pg/mL, NT-proBNP was falsely negative in up to 10% of CHF cases in overweight patients (25-29.9 kg/m2) and 15% in obese patients (> or =30 kg/m2). Using the standard cut point of 100 pg/mL, BNP testing was falsely negative in 20% of CHF cases in both overweight and obese patients. The assays for NT-proBNP and BNP exhibited similar overall sensitivity for the diagnosis of CHF.

CONCLUSIONS

When adjusted for relevant covariates, compared with normal counterparts, overweight and obese patients with acute CHF have lower circulating NT-proBNP and BNP levels, suggesting a BMI-related defect in natriuretic peptide secretion. NT-proBNP fell below the diagnostic cutoff for CHF less often than BNP in overweight and obese individuals; however, when used as a diagnostic tool to identify CHF in such patients, both markers may have reduced sensitivity.

Using BNP to develop a risk score for heart failure in primary care

AIMS

Chronic heart failure is a common condition with high mortality. Accurate diagnosis in primary care is difficult. Elevated B-type natriuretic peptide (BNP) is associated with left ventricular systolic dysfunction and increased mortality. Prognostic scoring systems using BNP may help to stratify risk in primary care patients. The aim of this research was to establish the independent variables which predict mortality in a primary care population-prescribed loop diuretics and to generate and validate a scoring system for heart failure in general practice.

METHODS AND RESULTS

Five hundred and thirty-two patients were followed up for a mean of 6.4 years after attending a research clinic for clinical assessment, electrocardiogram (ECG), echocardiography, and BNP. Multivariate analysis was used to establish independent prognostic variables and to generate a prognostic scoring system. The score generated was [0.50 x BNP+5 x age+50 x (CVA+sex+diabetes+ECG)]. The cut-off scores for risk groups were; 25th percentile, 411; 50th percentile, 475; 75th percentile, 524; Harrell's c=0.75.

CONCLUSION

Developing prognostic scoring systems provides a means of risk stratifying patients without relying on a single cut-off diagnostic value for BNP. Further validation of such scoring systems may improve future management of community heart failure patients.

Physician, organisational and patient characteristics explaining the use of angiotensin converting enzyme inhibitors in heart failure treatment: a multilevel study

OBJECTIVE

Heart failure treatment in general practice is not concordant with guideline recommendations. Insight into the key determinants at different levels is needed in order to improve care. The aim was to assess the influence of physician, organisational and patient characteristics on the treatment of chronic heart failure with angiotensin converting enzyme (ACE) inhibitors in primary care.

METHODS

Physician and organisational data were collected by means of a questionnaire. Patient and treatment data were extracted from electronic medical records. Multilevel analysis was used to assess the effect of physician, organisational and patient factors on the treatment with ACE inhibitors in terms of prescription rate and dosage.

RESULTS

Data from 735 randomly selected heart failure patients were extracted from the medical records of 95 general practitioners (GPs). Patients who visited a cardiologist or an outpatient heart failure clinic were more likely to receive an ACE inhibitor. In addition, relatively young patients, male patients and patients already using a diuretic were more likely to receive an ACE inhibitor. Furthermore, male patients and patients with concomitant hypertension were more likely to receive a higher dose of ACE inhibitor. GP characteristics did not determine whether CHF patients received ACE inhibitor treatment.

CONCLUSION

The differences in ACE inhibitor prescribing seem to be linked more to patient than physician characteristics. Interventions to improve the quality of care should therefore focus on the treatment of specific patient groups. Specialised care, particularly through outpatient clinics, could lead to improvement in the use of ACE inhibitors.

Difficulties of introducing the National Service Framework for heart failure into general practice in the UK

BACKGROUND

The National Service Framework (NSF) sets standards for the management of heart failure in the UK. Loop diuretics are commonly first prescribed in primary care. Some patients taking these drugs have heart failure and may benefit from other treatments including ACE inhibitors. Accurate diagnosis in primary care is essential for the aims of the NSF to be realised.

AIMS

To investigate loop diuretic prescribing in general practice, to analyse recorded clinical features, patient investigations and ACE inhibitor use in this population.

METHOD

One thousand three hundred and one patients taking loop diuretics were identified from prescription records of seven general practices. Demographic details, clinical features, investigations and drug treatments were extracted from patient records.

RESULTS

The prevalence of loop diuretic prescribing increased with age. Twenty percent of patients were attributed a diagnosis of heart failure but relevant clinical features were recorded in less than 50% of patient records. Open access echocardiography was used in 8.9% of patients. ACE inhibitors were prescribed in 39.8% of patients considered to have heart failure. 18.2% of these were taking the recommended target dose.

CONCLUSION

Loop diuretics are prescribed commonly, particularly in the elderly. There is no clear pattern of documented clinical features that leads to prescription of these drugs. Open access echocardiography is rarely used to aid diagnosis. ACE inhibitors are under-prescribed and under-dosed in patients diagnosed with heart failure in this study population.