July 15th, 2013
No Mortality Benefit for Surgery in Prosthetic Valve Endocarditis
Larry Husten, PHD
In the first five years after valve replacement approximately 3-6% of patients will develop prosthetic valve endocarditis (PVE). These patients are much more likely to die. Now a large observational study — the first of its type — has found that surgery is no better than medical therapy in reducing mortality in these patients. The report from the ICE-PCD (International Collaboration on Endocarditis — Prospective Cohort Study) investigators appears in JAMA Internal Medicine.
The trial followed 1,025 PVE patients, about half of whom had surgery (47.8% versus 52.2% who received medical therapy). Mortality, both in-hospital and at 1 year, was significantly lower in the surgery group. This was true using both unadjusted data and a multivariable model using a propensity score. However, after adjusting for survivor bias there were no significant differences between the two groups:
In-hospital mortality:
- Unadjusted hazard ratio: 0.68, CI 0.53-0.87
- Multivariable model: 0.44, CI 0.38-0.52
- Multivariable model controlling for survivor bias: 0.90, CI 0.76-1.07
One-year mortality:
- Unadjusted hazard ratio: 0.68, CI 0.55-0.87
- Multivariable model: 0.57, CI 0.49-0.67
- Multivariable model controlling for survivor bias: 1.04, CI 0.89-1.23
The investigators observed a significant improvement in mortality in the subgroup of surgical patients who had strong indications for surgery.
The findings, write the investigators, suggest that “survival bias and timing of surgery should be considered when evaluating the treatment effect on mortality.” Since patients in the study had surgery at a median of 8 days after hospital admission, the investigators pointed out that their study did not rule out possible benefits of very early surgery after admission.
In an accompanying editorial, Ann Bolger writes that the anatomic features of PVE “are dramatic and intuitively seem important to treat given that they are unlikely to improve with antibiotic therapy alone.” However, she writes,
“Impressive as these visible anatomic and functional features of PVE may be, perhaps we overvalue them in our overall assessment of patient risk. Guidelines have consistently emphasized these features as indicators of a need for surgery. However, their presence does not guarantee poor immediate outcomes. It is important, as we discuss treatment options with the patient and care team, that we be nuanced in our assessment of the patient’s comorbidities, as well as the individual patient’s ability to tolerate some of the functional sequelae of prosthetic infection.”
July 15th, 2013
Selections from Richard Lehman’s Literature Review: July 15th
Richard Lehman, BM, BCh, MRCGP
CardioExchange is pleased to reprint selections from Dr. Richard Lehman’s weekly journal review blog at BMJ.com. Selected summaries are relevant to our audience, but we encourage members to engage with the entire blog.
JAMA 10 July 2013 Vol 310
Prevalence and Extent of Obstructive CAD Among Patients Undergoing Elective Coronary Catheterization in New York State and Ontario (pg. 163): A clinical review in the NEJM a couple of months ago told us to change our whole conception about coronary atheroma: the really “critical” plaques may not be the ones that cause the obvious stenoses. On the contrary, the true villains are probably the deep soft fatty plaques that may not even disturb the lumen until they crack open and cause a thrombotic cascade. This thinking has yet to permeate the research literature, if it ever does: the “blocked” pipe analogy of CAD is so convenient for both patients and interventional cardiologists. And existing plaque is probably a good surrogate for hidden plaque, and should serve as a warning to use clot stabilising medications. I digress, led on by the fact that in New York State, nearly 70% of people subjected to coronary angiography have no obstructive atheroma, whereas in Ontario not far north, the figure is 55%.
Medical Management After Coronary Stent Implantation (pg. 189): I’m not a cardiologist, and I don’t get time to read all the specialist journals, but has there been any further work since COURAGE on stenting compared with various antithrombotic regimens for stable coronary disease? I’m led to wonder because there seem to be an awful lot of trials comparing agents after stenting—this review covers them—but not a lot about simply giving the drugs and omitting the stent. It seems to me that whenever a cardiologist does an angiogram on a person without unstable symptoms, all stents should be removed from the building, but maybe I’m missing something.
NEJM 11July 2013 Vol 369
CV Effects of Intensive Lifestyle Intervention in Type 2 Diabetes (pg. 145): What can we do about type 2 diabetes? At present we achieve most benefit by controlling blood pressure and prescribing statins, and a bit of good by keeping glycated Hb under 9%. But surely we would achieve the greatest reductions in cardiovascular events through an intensive lifestyle intervention to increase exercise and reduce weight? The Look AHEAD trial hoped to prove this within the pre-specified thirteen years, but instead it was abandoned for futility at 9.6 years. The patients in the intervention arm did well at keeping their weight down and having better levels of fitness; they even had lower sugar levels; but they did not score better on a composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for angina. This is a truly disappointing result from a well-designed non-drug trial which worked hard to achieve its desired surrogate end-points, but failed to achieve the end-points that mattered. Everybody would like to see a positive result from a trial in diabetes; but so far only bariatric surgery seems to deliver any goods, and that’s a message not one of us really likes to hear.
July 15th, 2013
The Conundrum of Low-Gradient Severe Aortic Stenosis with Preserved LVEF
Thomas Marwick and John Ryan, MD
CardioExchange’s John Ryan interviews Thomas Marwick about his research group’s study, published in Circulation, about how patients who have severe aortic stenosis with low gradient and a preserved LV ejection fraction fare after aortic valve replacement.
THE STUDY
Researchers prospectively identified 260 patients with symptomatic low-gradient severe aortic stenosis and followed them for a mean of 28 months. Nearly half (47%) underwent aortic valve replacement (AVR); the rest received optimal medical therapy alone. The mortality rate was significantly lower in the AVR group than in the medical group (30% vs. 70%). AVR remained a strong predictor of survival in propensity-matched analyses. AVR’s benefit was evident regardless of stroke volume index (SVi).
THE INTERVIEW
Ryan: Given your findings, should the standard of care for symptomatic low-gradient aortic stenosis be aortic valve replacement, or do we need a randomized controlled trial?
Marwick: It would be great to have an RCT, but in the current environment it will be hard to get funded, even in the U.S. Maybe this will be a spinoff of TAVR trials and, hence, funded by industry. Surgical trials are obviously hard to do. For now, this matched cohort study design is likely to be as good as we can manage. I think it helps me with the low-gradient patient when the surgeon says that an AVR will not have a much lower gradient than the native valve. These patients seem to benefit from surgery.
Ryan: How can we increase physicians’ awareness of this condition?
Marwick: I think there’s still a lot of confusion about what to do when the gradient and aortic valve area (AVA) don’t match. We all know that AVA is a derived parameter, so there is a tendency to underweight the AVA. Clearly, we should check the measurements, especially of the left ventricular outflow tract (LVOT). I think 3D has a real role in proper estimation of the LVOT. But when that has been done and the AVA is small in the setting of a low gradient, we shouldn’t ignore this, especially if the valve looks ugly and the stroke volume is reduced.
Ryan: In turn, are you worried that an emphasis on this condition could lead patients who do not actually have AS to be labeled with it?
Marwick: This is a real concern, but not as much as failing to intervene because AS has not been recognized. However, like most things in valve disease, it involves sensible integration of several parameters. If the valve opens adequately and the LVOT measurement is questionable, then making a call on AVA with a low gradient would be unwise. Sometimes transesophageal echocardiography, exercise testing, or more-advanced imaging might be needed.
Ryan: Should we have a standard approach to diagnosing low-flow AS?
Marwick: Again, I think it goes back to integrating several parameters and weighing their reliability. So it’s hard to make a recipe, but here’s what I do:
- Start with AVA, gradient, and dimensionless severity index (DSI). If they match up, it’s all good. If they don’t match, the next step is to explore why.
- Reassess the LVOT. If the image quality is horrible and you’re worried about the accuracy of LVOT measurement, down-weight AVA and use DSI.
- If the LV ejection fraction is poor or LV SVi is <35 mL/m2, I down-weight gradient.
- Watch out for the severity of morphologic changes in the AV.
- Keep an eye on the left ventricle. If LVEF is reduced, filling pressures are high, or there is unexpected LV hypertrophy (without other explanations), you might be missing an aortic valve problem.
JOIN THE DISCUSSION
Share your experiences with patients who have severe aortic stenosis with a low gradient and preserved LV ejection fraction. Will this study change your practice?
July 12th, 2013
Medtronic Faces Removal of CoreValve Transcatheter Heart Valve from German Market
Larry Husten, PHD
In the wake of a major patent decision, Medtronic will be forced to remove its CoreValve transcatheter heart valve from the German market. Edwards Lifesciences said today that a German Court had found that Medtronic infringed a key patent, known as the Spenser patent, and granted an injunction prohibiting the sale of CoreValve and CoreValve Evolut systems in Germany.
Medtronic said it would appeal the decision and that the action “will limit options for physicians and their patients who need transcatheter aortic valve procedures, which Medtronic believes is contrary to sound health policy.”
It should be noted that although the court found that Medtronic had infringed the Spenser patent, the validity of the patent itself is being contested. (In Germany the validity and infringement of patents are contested separately.) “Ultimately,” Medtronic said, it “believes that Edwards’ patent claims will be found to be invalid, which will negate today’s ruling of patent infringement.”
But the court decision today means that Medtronic will be forced to withdraw from the German market after Edwards posts a bond. Edwards noted that the Spenser patent is also in place in France, Italy, Spain, and other countries, raising the possibility that Medtronic may be forced to withdraw from additional markets in the future. The German ruling does not affect the status of other Medtronic products in Germany such as the Engager device, which is used for transapical procedures, and the MelodyPulmonic Transcatheter Valve.
Edwards and Medtronic are also engaged in litigation in the U.S. over a different Edwards patent, known as the Andersen patent. If Edwards prevails in the U.S., Medtronic might not be able to enter the U.S. market until 2016, according to Wells Fargo analyst Larry Biegelsen.
July 11th, 2013
Thrombolytic Therapy for Prosthetic Valve Thrombosis in Pregnant Women?
Mehmet Ozkan, Professor of Cardiology, Patricia Casais, MD, PhD and John Ryan, MD
CardioExchange’s John Ryan interviews Mehmet Özkan — lead author of a study, published in Circulation, of low-dose, slow-infusion t-PA in pregnant women with prosthetic valve thrombosis — and Patricia Casais, the lead author of the official editorial on the study.
THE STUDY
Twenty-four consecutive women who had 25 pregnancies and experienced 28 episodes of prosthetic valve thrombosis (PVT; 15 obstructive, 13 non-obstructive) received low-dose (25-mg) tissue plasminogen activator (t-PA) over the course of 6 hours. Thrombolytic therapy, under transesophageal echocardiography guidance, yielded complete thrombus lysis for all 28 PVT episodes. One patient had placental hemorrhage with preterm live birth at week 30, and one patient experienced minor bleeding.
THE INTERVIEW
Ryan: Should these findings change clinical practice?
Ozkan: Yes, we certainly think that our findings will change practice, and we suggest that thrombolysis should be used as first-line therapy for pregnant patients with mechanical valve thrombosis, especially in the U.S., where these patients usually end up undergoing surgery. We strongly encourage using our thrombolytic therapy protocol for such women, as we discussed in detail in our study. This may call for a change in guideline recommendations.
Casais: I think there is not yet enough evidence to recommend it as the therapy of choice. This paper is very promising, especially because it showed that thrombolytics are safe for the mother and the baby. In my opinion, the evaluation of its efficacy is more complicated, and given that it is closely related to the anticoagulant therapy after the thrombolysis, it might be difficult to assess. So what we mean by “successful thrombolysis” — and how and when to evaluate it — should be carefully defined (especially for a registry).
Ryan: If people start doing this, should we have some sort of international registry to track the experience?
Ozkan: Yes, we must have an international registry to track the experience with these patients. The cases are infrequent, and they receive variable treatments. It is virtually impossible for a single center to conduct a randomized study of these cases. The best treatment for these patients could be determined in international registry studies.
Casais: Definitely — an international registry is the most efficient way to get the information we need. Once we have that knowledge, we can assess whether this approach should change practice and become the therapy of choice for valve thrombosis in pregnancy. In addition, it would help to identify factors associated with good and poor outcomes.
Ryan: What kind of consent is necessary to provide this treatment?
Ozkan: To provide this treatment to a pregnant patient, we must obtain detailed thrombolytic therapy consent, including the risks to the mother and fetus. The consent form describing the risks to the mother could be the usual thrombolysis consent form for adults. However, the consent form describing the risks to the fetus should include short-term risks, such as fetal loss, and currently unknown long-term risks. Both parents need to give that consent.
Casais: The informed consent would need to state these points:
a. No standard therapy for valve thrombosis in pregnancy exists.
b. The approaches that might solve this complication are optimizing anticoagulant therapy, thrombolysis, and surgery — but each one of them has potential serious adverse outcomes (these should be specified). Not all of the approaches will be suitable for all patients.
c. Slow infusion of low-dose t-PA has been shown to be safe and efficacious in a series of patients, but more information is needed to identify the patients who would benefit the most from this treatment.
d. Prosthetic valve thrombosis is an infrequent complication, so it is difficult to evaluate which treatment is best in terms of safety and efficacy. An international registry would provide the data we need. Information in the registry must be confidential, of course, and meet other basic requirements.
JOIN THE DISCUSSION
Do you think thrombolytic therapy, as tested in this study, is ready for prime time? How do the new findings change your thinking?
July 11th, 2013
Link to Prostate Cancer Brings More Bad News for Fish-Oil Story
Larry Husten, PHD
Adding more confusion to an already fishy story, a new study has found a significant association between omega-3 fatty acids and the risk of prostate cancer. Although the link had been previously observed, the finding surprised the investigators, who wrote that “these findings contradict the expectation that high consumption of long-chain omega-3 fatty acids and low consumption of omega-6 fatty acids would reduce the risk of prostate cancer.”
In a report published in the Journal of the National Cancer Institute, investigators analyzed data from men who had participated in the SELECT (Selenium and Vitamin E Cancer Prevention Trial) trial. They compared 834 men who developed prostate cancer with 1,393 matched controls. When compared with men who had the lowest levels of omega-3 fatty acids, men in the highest quartile of omega-3 fatty acids were at significantly increased risk for low-grade, high-grade, and total prostate cancer:
- low-grade: hazard ratio = 1.44, CI 1.08-1.93
- high-grade: HR = 1.71, CI 1.00- 2.94
- total: HR = 1.43, CI = 1.09 to 1.88
Further contributing to the counter-intuitive findings, men with higher levels of trans-fatty acids had a lower risk for high-grade prostate cancer.
The authors concluded that despite the absence of a “coherent mechanism” to explain the finding, the available data,
“…suggests that long-chain omega-3 PUFA do play a role in enhancing prostate tumorigenesis. As has been made evident from many other clinical trials of nutritional supplements and cancer risk, the associations of nutrients with chronic disease are complex and may affect diseases differently. Long-chain omega-3 PUFA have been widely promoted for prevention of heart disease and cancer. Both this study and a recent meta-analysis of clinical trials showing no effects of long-chain omega-3 PUFA supplementation on all-cause mortality, cardiac death, myocardial infarction, or stroke suggest that general recommendations to increase long-chain omega-3 PUFA intake should consider its potential risks.”
The new study, although it did not specifically look at people taking fish-oil supplements, is the latest in a series of studies that have cast doubt on the benefits of fish oils and the wisdom of taking fish-oil supplements. Last year, a large meta-analysis and systematic review in JAMA found no cardiovascular benefits with fish-oil supplements. In May, a study from Italy published in the New England Journal of Medicine also found no benefits for people taking fish-oil supplements.
July 9th, 2013
Low Rate of Problems with Statins in Study of Quarter Million Patients
Larry Husten, PHD
A very large analysis of previously published studies finds that statins are generally safe and well tolerated, but helps confirm previous links to a small increased risk for diabetes and elevation of liver enzymes. Some statins were better tolerated than others, and lower-dose statins were better tolerated than high doses.
In a paper published in Circulation: Cardiovascular Quality and Outcomes, Huseyin Naci and colleagues report their findings from a systematic review of clinical trials with statins for both primary and secondary prevention. The data from 135 trials included nearly 250,000 subjects, comparing statins with placebo or with other statins. Previous analyses have generally confirmed the overall benign profile of statins but have not explored in depth the differences between individual statins and the effect of different doses of individual statins.
The new study found no differences between statins and placebo in the rate of discontinuations due to myalgia, CK elevation, and cancer, but statins were associated with a higher risk for diabetes (OR 1.09, CI 1.02-1.16) and transaminase elevations (OR 1.51, CI 1.24-1.84).
“I am concerned that patients may misunderstand this small increase in risk and stop adhering to their medications,” said Naci in an AHA press release, concerning the diabetes finding.
Simvastatin and pravastatin were better tolerated than other statins, while atorvastatin and rosuvastatin were associated with more discontinuations. People taking high doses of atorvastatin, fluvastatin, lovastatin, and simvastatin were more likely to have transaminase elevations. People taking high-dose simvastatin had an increased risk for CK elevations.
In recent years, the value of statins for primary prevention has been the subject of intense controversy. The authors write that recent studies have confirmed “that all- cause mortality benefits of statins in the primary prevention setting are clinically and statistically significant.” The new study, they say, gives “supporting evidence for initiating statin therapy in individuals who are at an increased risk of developing cardiovascular disease.” However, they acknowledge that “expanding the limits of statin therapy to a wider population of individuals may have important safety implications. Although rare, adverse events associated with statin therapy range from mild to moderate, and appear to increase with treatment intensity.”
The authors also acknowledge that although their “review did not find statistical evidence of myopathy, this may be due to an under-detection of muscle toxicity in clinical trials.” They conclude:
Our findings have important clinical implications. First, there is strong evidence that statins as a class are generally safe with uncommon side effects. According to the findings of this comprehensive analysis, there is consistently strong evidence on the comparatively favorable side effect profile of simvastatin and pravastatin – particularly at low to moderate doses – which should be favored in clinical practice. This meta-analysis sheds new light on the discussion on the relation between statins and diabetes incidence and confirms that statin use is not associated with cancer incidence. Finally, we acknowledge the complex nature of making prescribing decisions and urge prescribers to consider the findings of this analysis in light of the comparative benefit profiles of individual statins in preventing all-cause mortality in addition to cardiovascular and cerebrovascular events.
July 9th, 2013
Look AHEAD: More Questions Than Answers
Kasia Lipska, MD, MHS
Lifestyle approaches have long been the cornerstone of diabetes care. The diabetes epidemic has been driven largely by increasing obesity and changes in lifestyle; it follows logically that changing lifestyle should prevent and treat diabetes. Indeed, we know that lifestyle interventions reduce weight, improve well-being, decrease risk of diabetes, and can sometimes lead to remission of type 2 diabetes. However, it has been unclear whether lifestyle interventions for weight loss actually reduce cardiovascular events, the leading cause of morbidity and mortality in type 2 diabetes. The Look AHEAD study examined this very question and found that an intensive lifestyle intervention led to greater weight loss compared with a conventional diabetes support and education strategy among overweight or obese patients with type 2 diabetes, but did not result in a reduced rate of cardiovascular events. What do these findings mean for patients and health care systems?
First, should we hold lifestyle interventions to the same high standards of scrutiny as pharmacological interventions? It’s true that the primary outcome was negative, but there were many secondary outcomes that improved with the lifestyle intervention. This type of evidence should not be sufficient to approve a new drug, but isn’t it enough to promote changes in lifestyle? The safety of lifestyle interventions seems relatively well established. In fact, there seems to be little downside to encouraging diabetes patients to embark on an intensive lifestyle plan aimed at weight reduction. But, despite the fact that lifestyle interventions are overwhelmingly safer and less likely to result in adverse effects than are medications, there are potential downsides. We have to be fairly confident that lifestyle interventions are worth the cost, effort, and burden they impose – and this requires that we hold them to a relatively high standard when we evaluate their impact.
Second, don’t we already have enough evidence about the impact of lifestyle interventions to implement them in care? I admit that I am still enthusiastic about promoting lifestyle changes for my diabetes patients despite the fact that the primary outcome of the large, well-designed, long-term randomized controlled trial was negative. To me, this suggests that the trial may not have a huge impact on clinical practice – we already know that losing weight and exercising is good for health. Alternatively, I may be experiencing cognitive dissonance and unwilling to admit it!
The third question I will leave up for debate. I may be convinced about the benefits of lifestyle interventions, but will health care systems be willing to pay for them given the results of Look AHEAD?
July 8th, 2013
Selections from Richard Lehman’s Literature Review: July 8th
Richard Lehman, BM, BCh, MRCGP
CardioExchange is pleased to reprint selections from Dr. Richard Lehman’s weekly journal review blog at BMJ.com. Selected summaries are relevant to our audience, but we encourage members to engage with the entire blog.
JAMA 3 July 2013 Vol 310
Effect of Home BP Telemonitoring and Pharmacist Management on BP Control (pg. 46): If you identify people with poorly controlled blood pressure in primary care and introduce a system of intensive telemonitoring run by pharmacists according to a strict protocol, you are bound to get better BP control than if you leave it to “usual care.” But for each individual, the value of BP control will differ, as it does with every risk factor, and so will the adverse effects of treatment. You don’t need a doctor to measure BP but you do need someone in thoughtful dialogue with the patient to determine what the marginal value of further intensification might be. The simple “better control” trial described here didn’t really need to be done: anyone can intensify BP control, but the real question is whether such intensification is really worthwhile for the patients given their overall risk and personal preferences, and that goes well beyond a simple surrogate like BP.
Home-Based Walking Exercise Intervention in Peripheral Artery Disease (pg. 57): Again, if you take a group of people with peripheral artery disease and advise them to walk regularly, some will and some won’t; if you enroll them in weekly classes where they spend 45 minutes walking around and a further 45 being told how good it is for them to do this every day then you are bound to get better results. And again I puzzle as to whether this will work in real life: but it may well be worth a try, because in this case the patients are likely to notice a direct improvement in function.
Natriuretic Peptide-Based Screening and Collaborative Care for Heart Failure (pg. 66): In 2001 I proposed a study in which we would screen individuals with risk factors for heart failure to see if they had elevated BNP and treat them to reduce it. The MRC liked the idea and we did a pilot study, but found that BNP was too labile a marker to guide individual treatment decisions. The Irish team who report their similar study here achieved better success through a less ambitious protocol: starting in 2005, they cluster-randomised GP practices to screening for BNP or none: in the intervention practices they subjected the patients with high BNP to more intensive work-up and treatment and found that this somewhat reduced cardiovascular events and hospital admissions over 4 years. This trial raises more questions than it answers, but to deal with them would take a small book.
NEJM 4 July 2013 Vol 369
Clopidogrel with Aspirin in Acute Minor Stroke or Transient Ischemic Attack (pg. 11): A big Chinese trial establishes that in the population studied, adding clopidogrel to aspirin following a transient ischaemic attack or minor ischaemic stroke reduces the risk of a further stroke within 90 days, and does not carry a significant risk of major bleeding or haemorrhagic stroke. It looks like a well-conducted trial but the editorial poses some good questions about its generalisability to other populations. More big trials elsewhere, please.
BMJ 6 July 2013 Vol 347
When a Test Is Too Good: Pulmonary embolism is easily missed, and it appears in the BMJ series of that name. Pulmonary embolism is also easily overdiagnosed, and it appears in the first BMJ article in a new series called Too Much Medicine. It’s a question of balance: the lungs are meant to act as a sieve as well as an organ of oxygenation, and CT angiography may be making us aware of lots of debris that really doesn’t matter. Lifelong anticoagulation should not be embarked upon lightly. This is a cracking first article co-written by friends. For a contrasting patient’s perspective, go to John Launer’s beautiful piece in QJM.
July 4th, 2013
FDA: Olmesartan Can Cause Sprue-Like Enteropathy
Larry Husten, PHD
The FDA is warning that the angiotensin II receptor blocker olmesartan (marketed as Benicar, Benicar HCT, Azor, Tribenzor, and generics) may cause severe diarrhea. According to an FDA safety announcement, olmesartan “can cause intestinal problems known as sprue-like enteropathy. Symptoms of sprue-like enteropathy include severe, chronic diarrhea with substantial weight loss.” The warning is being added to the label of drug products containing olmesartan.
The FDA said that it has found no evidence that other angiotensin II receptor blockers increase the risk for sprue-like enteropathy.
The FDA recommends that physicians tell their patients taking olmesartan to contact them if the patients develop severe, chronic diarrhea with substantial weight loss. Symptoms may take months or years to develop after initiation of olmesartan therapy. The FDA advises physicians to look for other causes of the symptoms, including celiac disease. Olmesartan should be replaced with another antihypertensive agent if no other cause of symptoms is found.