Assessment and Treatment of Heart Failure

An audit was completed of 104 patients in whom the diagnosis of congestive heart failure had been made. Information was collected concerning the use of relevant medications, referral patterns to cardiology and investigations. The results indicate a significant proportion of those diagnosed with congestive heart failure are not on optimum medication regimes. There was low uptake of echocardiography overall. There was high correlation between seeing a cardiologist and taking a beta-blocker and there was a high correlation between having an echocardiogram and taking a beta-blocker. The results suggest that significant improvement is possible in the primary care treatment of congestive heart failure. Access to accurate diagnosis, either through specialist referral or echocardiography, would be likely to improve pharmacological therapy.

Introduction

Significant changes have occurred in recent years concerning the recommended treatment of congestive heart failure. There is convincing evidence that pharmacological interventions such as optimum dose ACE inhibition , beta-blockers and spironolactone can reduce both mortality and hospital admissions. The hospital management of congestive heart failure consumes up to 1.5% of the health budget, yet there are also indications that there is only sporadic uptake of these pharmacological interventions in primary health care . This audit was designed to examine the use of diagnostic tools and pharmacological interventions in those diagnosed with heart failure in general practice. The study was undertaken in the Waikato region of New Zealand and included two urban practices and one rural

Methods

Three general practices were approached in regard to their interest in becoming involved in the audit process. All three agreed to be entered in the audit. The practice identified all those enrolled in the practices that were coded with the diagnosis of heart failure. An audit sheet was completed by the nurse with details of medications prescribed, investigations undertaken, classification of severity of heart failure and whether an opinion from a cardiologist had been given. The results were centrally collated, and summarized with no identifying data.

Results

A total of 104 subjects were identified as having a diagnosis of congestive heart failure.

Classification
There was virtually no record of systematic classification of the severity of heart failure according to the New York Heart Association guidelines.

For the purpose of this audit all ACE inhibitors were considered as a single group. A total of 67 (64%) of subjects were on an ACE inhibitor. However, of these 67 subjects, only 26 (36%) were considered to be on optimal dose of ACE inhibition as defined by The Heart Foundation . It is unclear why optimum doses of ACE are not used in all those who can tolerate the medication.

30 (28%) of enrolled subjects were on a beta-blocker. Because of lack of classification of heart failure, it is difficult to assess what percentage of subjects should be treated with these medications. Of the 30 subjects who were on a beta-blocker, 25 had seen a cardiologist.

The number of subjects who were prescribed spironolactone was 17%. The accepted indication for the use of spironolactone in heart failure is in New York Heart Association class 3 or 4. Since there was very little data on the severity or classification of heart failure, the relevance of this figure in terms of optimal pharmaceutical intervention is difficult to analyze.

Of the 104 subjects 59 (57%) had undergone echocardiography and 61% had a record of chest x ray. Only one third of echocardiography reports contained information on ejection fraction. Of those who had an echocardiogram, 21(70%) were on beta-blockers. This compares to 9 (30%) who were on beta-blocker but who did not have an echocardiogram.

Referral to the patient having had a cardiology opinion was available for 67% of patients. Interestingly, of the 70 subjects who had been referred for a specialist's opinion, only 51 (72%) had evidence in the patient file of having had echocardiogram. As stated above, seeing a specialist was highly predictive of being prescribed a beta-blocker.

Discussion

The use of beta-blockers in congestive heart failure raises many issues. It challenges the old wisdom of "never prescribe beta-blockers in someone with heart failure" that many general practitioners were taught. This may account for some of the resistance to the use of such medication in heart failure. Another factor that may explain this low uptake of beta-blockers in treating heart failure is the perception of frequent adverse events associated with this medication overall . However, this perception is not supported by evidence. Indeed a recent meta analysis of adverse effects associated with beta-blockers would indicate that the rate of specific adverse effects of fatigue and sexual dysfunction is low with respective numbers needed to harm (NNH) of 57 and 199, and there was no reported increase in depressive symptoms .
The symptoms of heart failure are non-specific; without a more accurate diagnostic tool such as echocardiography, many general practitioners may also be reluctant to start such medication because of the risk of adverse events. Another confounding variable is the lack of classification of severity of heart failure. The clinical trials concerning the use of beta-blockers in heart failure do not, as yet, conclude benefit in those with severe heart failure (New York Heart Association 4). It is unknown how many of the subjects enrolled had severe (NYHA grade 4) heart failure but the numbers with this degree of severity are unlikely to account for the 72% of subjects not prescribed beta-blockers. There may be other explanations for the high numbers not on beta-blockers such as concurrent asthma, intolerance, peripheral vascular disease etc.
Echocardiography has become an important tool in the accurate diagnosis and appropriate management of congestive heart failure . Open access for general practitioners to echocardiography has been studied previously with generally positive results. The influence of echocardiogram in predicting the use of beta-blockers in this audit is of interest. Those who had echocardiogram were more than twice as likely to be on beta-blockers than those who did not have echocardiogram.
It is interesting to note the lack of systematic classification of the severity of heart failure in primary care. The number of patients with heart failure that are enrolled in the care of each general practitioner are relatively small and thus on an individual practitioner basis, a systematic classification system may not be clinically useful. However, on a population basis, such classification systems allow more accurate assessment of the adequacy of treatment.

Conclusions

There is need for further increase of awareness in primary health care that high dose ACE inhibition is recommended in treating heart failure. However, the barriers to optimum dosage of ACE are multifactorial and educational initiatives alone may not significantly improve levels of optimum treatment. Further study is needed to understand the nature of these barriers.
Classification of the severity of heart failure according to the New York Heart Association guidelines would assist in optimal management on a population basis but is underused in primary health care. Systematic audit of management based on the severity of the disease would be likely to improve clinical outcomes.
Undergoing an echocardiogram and seeing a cardiologist were both predictive of using beta-blockers. The current pathway to having an echocardiogram in the public system is exclusively through a cardiologist; therefore it is impossible to separate the influence of these variables on the rate of beta-blocker use in heart failure. Beta-blockers are clearly underused in the primary care management of this disease. The finding of an association between echocardiography and use of beta-blockers would suggest that better access to this investigation would result in higher rates of optimal pharmacological intervention, and use of beta-blockers in this group should result in a subsequent reduction in hospital admissions . If open access to echocardiography were to be offered to general practitioners in the management of suspected heart failure, clear guidelines would be needed to increase awareness of both the indications and the limitations of the investigation.

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Contact details:
Steven Lillis, Senior Lecturer, Waikato Clinical School, Waikato hospital, Pembroke St, Hamilton

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