Better Cardiac Care measures for Aboriginal and Torres Strait Islander people: second national report 2016

This is the second national report on the 21 Better Cardiac Care measures for Aboriginal and Torres Strait Islander people, with updated data available to report on 11 measures. For some of the measures, a better or similar rate for Indigenous Australians compared with non-Indigenous Australians was apparent, while on other measures, higher rates of ill health and death from cardiac conditions and lower rates of in-hospital treatment services among Indigenous Australians were evident. A number of measures suggested improvements for Indigenous Australians over time; examples include a decline in the death rate due to cardiac conditions and an increase in the proportion who received an MBS health assessment.

AMA at the table on health insurance reforms

The Federal Government continues with its reforms to health care, shifting focus to the private health sector.

Health Minister Sussan Ley has recently established a Private Health Ministerial Advisory Committee (PHMAC) to develop recommendations across a range of policy areas relevant to private health.

The PHMAC follows on the work earlier in the year of an industry working group on reforms to the Prostheses List. The Prostheses List sets out the reimbursement amounts for thousands of prostheses used in the private health system.

The Minister has announced reductions in the benefit amounts for some prostheses to support a reduction in cost to private health insurers and a consequential reduction in private health insurance premiums for consumers.

The benefits for a small number of prostheses will be reduced from February 2017, including a:

10 per cent reduction across the cardiac devices category;
10 per cent reduction to the ophthalmic (intraocular lenses) category;
7.5 per cent reduction across the hip product category; and
7.5 per cent reduction across the knee product category.

In total, these reductions are expected to deliver savings of $86 million to health funds in the first year, and $394 million over five years. The Minister has also announced moves towards a more transparent pricing model with open disclosure.

The work of the PHMAC is now underway as the second part of the reforms.

The Committee’s terms of reference include a closer examination of private health insurance (PHI) product design with simplified consumer products; standard product categories; the role of exclusions and restrictions; appropriate excess levels; and the scope of services covered by PHI.

The Committee will also look at consumer information; premium setting; second tier default benefits; risk equalization; single billing; lifetime health cover; and providing better value for rural and remote consumers.

The first meeting of the PHMAC considered some early thinking from the private health insurers on product design and a potential ‘Gold/Silver/Bronze’ product classification model.

These are all important areas for review.

The AMA has a strong interest in the work of the Committee and its outcomes.

The AMA has a commitment to a viable private health sector and sees the work of the Committee as key to strengthening the sector and maintaining its relevance and attractiveness to patients into the future.

I am representing the AMA on the PHMAC, using a reference group of senior clinicians to provide advice in the lead in to each meeting.

The AMA will make available on its website the outcomes from each meeting (which are circulated for publication).

I welcome comment and input from members. The work of PHMAC will inform the shape of private health care funding for years to come. It is important that the AMA voice is heard.

Functional mitral valve regurgitation: repair or replacement?

Long term outcomes primarily depend on left ventricular function

Primary mitral valve disease involves damage to leaflet or chordal tissue,1 whereas functional (or secondary) mitral regurgitation (MR) typically involves a combination of mitral annular dilatation and leaflet restriction caused by ventricular dysfunction in patients with normal leaflets and chordae. Assessing the severity of regurgitation in secondary MR is more difficult than in primary MR, as the regurgitant orifice area is often underestimated by echocardiography because of its crescent shape during systole. Left ventricular stroke volume is usually reduced in secondary MR, so that lesser degrees of regurgitant volume are more significant.

Mitral annular dilatation can follow left ventricular dilatation caused by dilated cardiomyopathy or myocardial infarction. Mitral and tricuspid dilatation can also occur as a consequence of atrial dilatation resulting from long-standing atrial fibrillation. This usually affects the tricuspid to a greater extent, but can still cause symptomatic MR that requires surgery.

Functional MR is thus a left ventricular condition,2 and anti-failure medical therapy is the critical first component of management. Some patients present with dyssynchrony of ventricular contraction, and can benefit from biventricular pacing.3 The traditional technique for repair is to perform a mitral annuloplasty, which aims to bring the posterior (free wall) of the annulus forward and thereby move the posterior mitral leaflet closer to the anterior leaflet, enlarging the coaptation zone. This works well on the operating table, but with time the left ventricle can re-dilate, which in many patients results in the posterior leaflet being drawn further down than can be compensated by the annuloplasty. In fact, regurgitation can be increased in some patients as tethering of the leaflets becomes more prominent, pulling the edges of the leaflets into the ventricle and decreasing the amount of coaptation between the leaflets.

Mitral valve replacement has historically been associated with a higher mortality rate than mitral valve repair across all categories.4–6 Data from the National Cardiac Surgical Database6 indicate a mortality rate in Australia of about 1% for isolated mitral repairs (largely myxomatous disease), but 4–6% for mitral valve replacement (myxomatous and rheumatic disease). Mortality increases markedly if concomitant coronary surgery is undertaken: coronary grafting with valve repair is associated with 4–6% mortality, or 8–12% if the valve is replaced.6 Some of this mortality is due to selection bias, but some is directly associated with the surgery. Placing a rigid, circular prosthetic valve in a dynamic, D-shaped muscular orifice can adversely affect ventricular function, as can failure to preserve papillary muscle continuity with the mitral annulus.

The mortality associated with surgery for functional MR depends on the degree of ventricular impairment, but ranges between 5% and 20% or more for patients with severe impairment. However, the results of valve repair in functional MR have been variable, with about one-third of patients experiencing the return of significant regurgitation within 3 months of surgery; on the other hand, the operative risk is lower than for valve replacement.4,5 The recurrence of regurgitation is explained by the inability to control the size and shape of the left ventricle in many patients. If the regurgitation is caused by annular dilatation with minimal leaflet restriction, annuloplasty is a good option with acceptable results. If there is significant tenting (the coaptation plane of the valve is more than 1 cm below the plane of the annulus), annuloplasty alone will not reliably achieve a competent valve, and valve replacement is preferred. Left ventricular size is the main factor, with an end diastolic diameter greater than 65 mm associated with poorer long term survival and repair results.

Other techniques for repairing the valve have been investigated. Some surgeons place a tape around the bases of the papillary muscles and draw them together to reverse the displacement caused by left ventricular dilatation.7,8 Techniques for internally splinting the left ventricle with Gore-Tex neochords or using external ventricular wraps have been tried. Other surgeons have attempted to enlarge the anterior mitral leaflet with a patch in order to move its coaptation edge back to meet the displaced posterior leaflet.9 A frequently used alternative is the edge-to-edge repair introduced by Alfieri, which can be used in both primary and secondary MR.10–12

There has been much debate about which approach achieves the best outcomes, a discussion complicated by the variations in results and case selection in published reports.

Patients with ischaemic cardiomyopathy can present for coronary surgery with any degree of MR, or with heart failure resulting from ventricular dysfunction and MR. Patients undergoing coronary artery surgery with moderate regurgitation can be managed with an annuloplasty during coronary artery surgery. A recent update on a large randomised trial13 has confirmed this consensus but questioned the benefit of the approach, the authors finding that survival and re-admission for heart failure were the same at 2 years, regardless of whether the valve had been repaired. Adding mitral valve repair to the coronary surgery prolonged the operation time, as expected, but also increased the stroke rate and atrial arrhythmias. Repair resulted in less MR, but coronary grafting alone often achieves this outcome. Ventricular re-modelling was better, however, in patients with less regurgitation. The problem is that it is difficult to define before the operation which ventricles will improve with revascularisation alone, and therefore which need mitral repair. It is notable that moderate to severe regurgitation was much more common if repair was not undertaken.13

Most importantly, long term outcomes depend primarily on left ventricular function. Patients with moderate to severe ischaemic MR who are having coronary surgery need a competent mitral valve. They usually have severe ventricular dysfunction and will not tolerate a failed repair, so that replacement has been the preferred option in most cases. The mortality risk for this subgroup is high, and mitral valve repair should be reserved for surgeons with a particular interest and experience in this field.14

Dilated cardiomyopathy can lead to both annular dilatation and papillary muscle displacement.2 Mitral valve repair in this group is challenging, again because of the inability to control the size of the ventricle over time, leading to recurrent regurgitation. These patients can present with improved ventricular function when they develop MR, as the ventricle empties into the pulmonary circulation. Left ventricular function deteriorates when the mitral valve is made competent, which increases the afterload against which the ventricle must eject its blood.

Severe MR is a common late feature of the dilating failing heart. Surgery in these patients is associated with a high risk of mortality, and should only be undertaken when supported by resources for managing heart failure after the operation, including short or long term ventricular support devices and, possibly, cardiac transplantation, depending on the clinical setting.

Cardiac surgery on patients with irreversibly damaged ventricles can be very risky, with long post-operative recovery periods. To reduce this morbidity, new technologies are being introduced. The Alfieri suture, for example, attaches the centre of the two mitral leaflets to limit abnormal leaflet motion, thereby improving mitral valve competency.10 A percutaneous catheter-based version of this approach is now used, the MitraClip; it is inserted in the catheter laboratory under fluoroscopic and echocardiographic guidance. It usually improves both regurgitation and functional class by one to two grades, which can be a major clinical improvement in this difficult to treat group of patients.15 However, many cases are not anatomically suitable for the MitraClip, and the patients need a replacement valve. Several new mitral implants currently undergoing trials are placed through the apex of the left ventricle, but do not require cardiopulmonary bypass, and can therefore reduce surgical stress for the patient. Time is needed to determine how effective they are with respect to ease of implantation and the relief of symptoms, as well as to ascertain any survival benefit.

Conclusion

Functional MR is usually caused by ventricular dysfunction. Mild to moderate degrees of MR can be readily treated with standard annuloplasty techniques. Their benefit, however, is questionable, and the operation should only be undertaken when performing coronary artery surgery if the additional operative risks can be justified. Moderate to severe regurgitation is more reliably corrected by replacing the valve, either in isolation or together with coronary surgery. The degree of left ventricular dysfunction determines the quality of the long term outcome, making these patients particularly challenging during the post-operative period. Newer catheter-based and off-pump techniques are being introduced that will help palliate the hazard for these high risk surgery candidates.

[Interactive Grand Round] Severe respiratory failure

A 41-year-old man presents with flu-like symptoms and severe respiratory distress. What are the management priorities? What techniques can be used to manage his respiratory failure? Despite optimal respiratory management the patient’s condition deteriorated, and he developed a troponin rise that remained static, associated with regional wall motion abnormalities on echocardiography. What cardiac imaging tests would best identify the potential aetiology?

High-intensity statins do save lives, says US study

A US-based study of more than 500,000 patients with atherosclerotic cardiovascular disease (ASCVD) found that those who received high-intensity statins saw their mortality risk significantly reduced.

The study, published online by JAMA Cardiology, examined one-year cardiovascular mortality rates by intensity of statin therapy among patients aged 21 to 84 years with ASCVD treated under the Veteran Affairs health care system.

The study sample included 509, 766 eligible adults with ASCVD at study entry, including 30 per cent receiving high-intensity statin therapy, 46 per cent receiving moderate-intensity stain therapy, 6.7 per cent receiving low-intensity statin therapy, and 18 per cent receiving no statins. The intensity of the statin therapy was defined by the 2013 American College of Cardiology and the American Heart Association guidelines, and use was defined as a filled prescription in the prior six months.

During an average follow-up of 492 days, there was a graded association between intensity of statin therapy and mortality. The researchers also found that maximal doses of high-intensity statins conferred the greatest survival advantage compared with submaximal doses of high-intensity statins.

Statin therapy remains the cornerstone for the prevention of ASCVD. Many large, randomised trials have shown that the use of statins significantly reduces the likelihood of future cardiovascular events and mortality in diverse populations. Nevertheless, statin therapy in general, and high-intensity statin therapy in particular, is underused in patients with established ASCVD. The Veterans Affairs health care system has released dyslipidemia guidelines that recommend moderate-intensity statins for most patients with ASCVD, citing insufficient evidence for recommending high-intensity statin therapy except in some subgroups of patients at high risk for ASCVD.

Paul A. Heidenreich from Stanford University and his colleagues wrote that the study offered evidence to significantly improve the treatment of ASCVD.

“These findings suggest there is a substantial opportunity for improvement in the secondary prevention of ASCVD through optimization of intensity of statin therapy,” they wrote.

Latest news

[Correspondence] The ABC risk score for patients with atrial fibrillation – Authors’ reply

We thank the correspondents for their comments on our Article1 concerning the new biomarker-based age, biomarkers, and clinical history (ABC)-bleeding risk score in patients with atrial fibrillation. The biomarker field has matured greatly in recent years and acquired increased notice also in clinical cardiology guidelines.2 Apart from the robust methods by which the ABC-bleeding risk score was developed and validated, another key advantage of the score is easy adaptability, in terms of use and future refinement.

[Correspondence] The ABC risk score for patients with atrial fibrillation

The study by Ziad Hijazi and colleagues (June 4, p 2302)1 provides a comprehensive validation of the age, biomarkers, and clinical history (ABC)-bleeding score, using age, three biomarkers (haemoglobin, cardiac troponin T, and GDF-15), and clinical history of bleeding to predict major bleeding events in anticoagulated patients with atrial fibrillation. Although the clinical usefulness of this approach to tailor stroke and bleeding risk in individual patients awaits further validation in real-world cohorts, the study by Hijazi and colleagues1 is a great leap forward in precision medicine and risk stratification in atrial fibrillation.

[Correspondence] The ABC risk score for patients with atrial fibrillation

Ziad Hijazi and colleagues’1 age, biomarkers, and clinical history (ABC) score yields promise as a new standard for assessment of bleeding risk in patients with atrial fibrillation and supports the role of biomarkers in the field of arrhythmic disorders. Unfortunately, it also highlights the overlap of some variables (GDF-15, cardiac troponin T, and age), which are not only associated with bleeding, but are also known risk factors for stroke and systemic embolism.2,3 New thromboembolic risk stratification schemes such as ATRIA,4 R2CHADS2,5 and ABC-stroke6 have been proposed, but the time has come for a new notion of integrated risk stratification for patients with atrial fibrillation.

A new model to predict acute kidney injury requiring renal replacement therapy after cardiac surgery [Research]

Background:

Acute kidney injury after cardiac surgery is associated with adverse in-hospital and long-term outcomes. Novel risk factors for acute kidney injury have been identified, but it is unknown whether their incorporation into risk models substantially improves prediction of postoperative acute kidney injury requiring renal replacement therapy.

Methods:

We developed and validated a risk prediction model for acute kidney injury requiring renal replacement therapy within 14 days after cardiac surgery. We used demographic, and preoperative clinical and laboratory data from 2 independent cohorts of adults who underwent cardiac surgery (excluding transplantation) between Jan. 1, 2004, and Mar. 31, 2009. We developed the risk prediction model using multivariable logistic regression and compared it with existing models based on the C statistic, Hosmer–Lemeshow goodness-of-fit test and Net Reclassification Improvement index.

Results:

We identified 8 independent predictors of acute kidney injury requiring renal replacement therapy in the derivation model (adjusted odds ratio, 95% confidence interval [CI]): congestive heart failure (3.03, 2.00–4.58), Canadian Cardiovascular Society angina class III or higher (1.66, 1.15–2.40), diabetes mellitus (1.61, 1.12–2.31), baseline estimated glomerular filtration rate (0.96, 0.95–0.97), increasing hemoglobin concentration (0.85, 0.77–0.93), proteinuria (1.65, 1.07–2.54), coronary artery bypass graft (CABG) plus valve surgery (v. CABG only, 1.25, 0.64–2.43), other cardiac procedure (v. CABG only, 3.11, 2.12–4.58) and emergent status for surgery booking (4.63, 2.61–8.21). The 8-variable risk prediction model had excellent performance characteristics in the validation cohort (C statistic 0.83, 95% CI 0.79–0.86). The net reclassification improvement with the prediction model was 13.9% (p < 0.001) compared with the best existing risk prediction model (Cleveland Clinic Score).

Interpretation:

We have developed and validated a practical and accurate risk prediction model for acute kidney injury requiring renal replacement therapy after cardiac surgery based on routinely available preoperative clinical and laboratory data. The prediction model can be easily applied at the bedside and provides a simple and interpretable estimation of risk.

[Articles] Dexmedetomidine for prevention of delirium in elderly patients after non-cardiac surgery: a randomised, double-blind, placebo-controlled trial

For patients aged over 65 years who are admitted to the intensive care unit after non-cardiac surgery, prophylactic low-dose dexmedetomidine significantly decreases the occurrence of delirium during the first 7 days after surgery. The therapy is safe.