The Doctor's Channel - Cardiology

Thyroid hormone analogue shows promise for statin-treated dyslipidemia

2010-03-12T21:09:30+00:00

NEW YORK (Reuters Health) – When statins alone can’t reverse dyslipidemia, the thyroid hormone analogue eprotirome may be helpful, new research suggests.

In a 12-week study of 189 dyslipidemic, statin-treated patients, eprotirome safely reduced the levels of various atherogenic lipoproteins, the investigators report in The New England Journal of Medicine for March 11.

In the study, subjects continued to receive simvastatin or atorvastatin and were randomized to receive eprotirome (25, 50, or 100 micrograms/day) or placebo.

With the 25, 50, and 100 microgram doses of eprotirome, mean low density lipoprotein (LDL) cholesterol levels fell by 22%, 28%, and 32%, respectively, from a baseline value of 141 mg/dL. By contrast, placebo produced a mean reduction of just 7%. Eprotirome had a similar effect on levels of serum apolipoprotein B, triglycerides, and Lp(a) lipoprotein.

Eprotirome was generally well tolerated, with no adverse cardiac or bone effects. Although thyroxine levels fell in patients receiving the drug, serum levels of thyrotropin and triiodothyronine did not change.

“This randomized, placebo-controlled, double-blind trial showed that eprotirome is associated with further reductions in serum LDL cholesterol levels in patients who are already receiving statins,” the authors conclude. “Eprotirome also has potent properties for lower levels of apolipoprotein B, triglycerides, and Lp(a) lipoprotein.”

The study was supported, in part, by Kara Bio, the company developing eprotirome.

Reference:
N Engl J Med 2010;362:906-916.

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Cardiac catheterization has low diagnostic yield

2010-03-11T22:49:39+00:00

NEW YORK (Reuters Health) – Just 38% of patients with suspected cardiac disease are found to have obstructive coronary disease on elective cardiac catheterization, new research shows. This low diagnostic yield suggests that clinical assessments and noninvasive tests are not doing their job in selecting patients for cardiac catheterization.

“Guidelines recommend continued observation in the case of patients who are at very low risk, noninvasive stress testing to determine the need for cardiac catheterization in the case of patients at intermediate risk, and direct referral for catheterization in the case of patients at high risk,” lead author Dr. Manesh R. Patel and colleagues note.

But whether these recommendations help limit the number of patients without coronary disease who undergo cardiac catheterization was unclear, according to the report in The New England Journal of Medicine for March 11.

To investigate, Dr. Patel, from Duke University Medical Center, Durham, North Carolina, and colleagues analyzed national registry data on nearly 400,000 patients without known coronary disease who had elective cardiac catheterization at 663 hospitals in the U.S.

Obstructive coronary disease was defined as stenosis of at least 50% of the diameter of the left main coronary artery or stenosis of at least 70% of the diameter of a major epicardial vessel.

The median patient age was 61 years and 52.7% of patients were male. Twenty-six percent of subjects had diabetes and 69.6% had hypertension. Roughly 84% had noninvasive tests before cardiac catheterization.

Only 37.6% of patients had obstructive coronary disease at catheterization, the report indicates. Moreover, 39.2% of patients had no coronary disease (stenosis <20% in all vessels).

A positive noninvasive test result slightly increased the likelihood of finding obstructive disease: 41.0% vs. 35.0% (adjusted odds ratio, 1.28, p < 0.001).

In an editorial, Dr. David J. Brenner from Columbia University Medical Center in New York agrees with the authors that a better “gatekeeper” test is needed to select the best candidate for cardiac catheterization. “Ironically,” he notes, “there is evidence that, in many situations, a better gatekeeper test may be yet another radiographic imaging technique—namely, multidetector-row computed-tomographic angiography.”

Reference:
N Engl J Med 2010;362:886-895,943-945.

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Women benefit as much as men from statins for primary prevention of CVD

2010-03-11T22:44:28+00:00

NEW YORK (Reuters Health) - Statin use by women cuts their risk of primary cardiovascular disease (CVD) events by roughly a third, which is similar to the risk reduction seen in men, research shows.

"Statin therapy in women without CVD is controversial, given the insufficient evidence of benefit," Dr. Samia Mora, from Brigham and Women's Hospital, Boston, and colleagues note in the March 9th issue of Circulation.

Dr. Mora and colleagues analyzed gender-specific outcomes from the randomized JUPITER trial and performed a meta-analysis of statin trials that focused on women.

JUPITER included 6801 women at least 60 years of age, and 11,001 men at least 50 years of age. All had high C-reactive protein levels (at least 2 mg/L) and normal to low levels of low density lipoprotein cholesterol (no higher than 130 mg/dL). Participants took either rosuvastatin or placebo daily.

The meta-analysis included 7 primary prevention trials, with 13,154 women who had 240 CVD events and 216 deaths.

Compared to the men in the JUPITER trial, the women had lower absolute CVD rates per 100 person-years (0.57 vs. 0.88 for rosuvastatin groups and 1.04 vs. 1.54 for placebo groups) - but both genders had relative risk reductions of roughly 44%.

Further analysis showed that statin therapy significantly reduced revascularization and unstable angina in women, but did not affect other CVD events.

In the meta-analysis, statin use by women cut primary CVD events by 37% (p < 0.001), but did not significantly affect total mortality.

When the results of JUPITER and the meta-analysis are taken together, the researchers conclude, "statin therapy resulted in about a one-third relative reduction in primary CVD in women, a benefit similar to that seen in previous meta-analyses of men."

Reference:
Circulation 2010;121:1069-1077.

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Longer follow-up confirms advantage of sirolimus-eluting vs bare metal stents

2010-03-10T16:43:41+00:00

NEW YORK (Reuters Health) – Three years after ST-segment elevation myocardial infarction (STEMI), sirolimus-eluting stents still provide better protection against major adverse cardiovascular events compared to bare metal stents, new research shows.

The findings are based on 3 years of data from the randomized SESAMI trial. The 1-year results from SESAMI indicated superior outcomes with sirolimus-eluting stents.

Until now, however, long-term safety and efficacy data for sirolimus-eluting stents in STEMI patients came only from registries, according to author Dr. Carmine Musto, from San Camillo Hospital, Rome, and colleagues.

As reported in the February 23rd Journal of the American College of Cardiology, SESAMI included 320 patients, with long-term data available for more than 97% in each group.

The primary outcome – the incidence of major adverse cardiovascular events at 3 years – was 12.7% with sirolimus-eluting stents vs 21% with bare metal stents (p = 0.034). The endpoint was a composite of cardiac and noncardiac death, Q-wave and non-Q-wave infarction, coronary artery bypass graft surgery, or target lesion revascularization.

Patients with sirolimus-eluting stents also had significantly lower rates of target lesion revascularization (7% vs. 13.5%, p = 0.048), target vessel revascularization (8% vs. 16%, p = 0.027), and target vessel failure (11.5% vs. 20.5%, p = 0.028) compared to patients with bare metal stents.

In addition, significantly more sirolimus-treated patients were alive and free from these adverse outcomes (87% to 93%, depending on the event) compared to patients with bare metal stents (79% to 86.5%; p < 0.05). Prevention of target lesion revascularization drove the benefit of the drug-eluting stents, and this was first apparent in the first year of follow-up.

After clopidogrel was discontinued, the two groups had similar cumulative rates of death and recurrent myocardial infarction, the report indicates.

The study had two principal limitations, the authors note. First, it examined only clinical endpoints. Second, it was not powered to detect differences in cardiac event rates between 12 and 36 months.

Reference:
J Am Coll Cardiol 2010;55:810-814.

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Emboli filters during PCI lead to higher risk of stent thrombosis

2010-03-09T16:49:30+00:00

NEW YORK (Reuters Health) - Using a distal filter to protect against emboli during coronary stent implantation increases long-term rates of stent thrombosis and target vessel revascularization, investigators in Denmark report.

Randomized trials have shown no benefit of distal protection in the short or intermediate term after percutaneous coronary intervention (PCI), Dr. Anne Kaltoft from Aarhus University Hospital, Skejby, and her associates note. Their article in the Journal of the American College of Cardiology for March 2 reports their 15-month follow-up of patients treated for ST-elevation myocardial infarction in the DEDICATION trial.

Patients received aspirin, clopidogrel, and unfractionated heparin in advance of the procedure. If a cardiologist believed that a wire filter could be advanced (based on pre-dilation and initial visualization of the peripheral vascular bed), the researchers then randomized the patient either to distal protection (n = 312) or conventional treatment (n = 314).

In the distal protection group, filter placement was attempted in 304 patients (97%) and was successful in 254 patients (81%).

But filter protection afforded no benefit at either 30 days, 6 months, or 15 months later, the researchers said.

Nine cases of definite stent thrombosis occurred in the protection group and one in the control group (2.9% vs 0.3%, p = 0.01).

The rate of target lesion revascularization was also significantly increased in the distal protection group (12.5% vs 7%, p = 0.05), as was the rate of target vessel revascularization (15.4% vs 8.3%, p < 0.01).

The two groups had similar rates of myocardial infarction and mortality.

Dr. Kaltoft's team suggests that vessel spasm in response to filter placement could lead "to an underestimation of the vessel diameter and to undersizing of the implanted stent, a known predictor of early stent thrombosis." Other possibilities include damage to the vessel wall at the site of filter deployment or stent apposition during filter retrieval.

Similarly, damage to the vessel wall from pre-dilation or during placement of the filter could increase restenosis rates and the need for repeat revascularization.

Whatever the cause, the authors conclude, "Routine use of a filter wire in its present form cannot be advocated and probably should be avoided with primary PCI for ST-elevation myocardial infarction."

Reference:
J Am Coll Cardiol 2010;55:867-871.

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Cardiac vegetations don't rule out percutaneous ICD lead extraction

2010-03-08T19:26:08+00:00

NEW YORK (Reuters Health) - Percutaneous extraction of pacemaker or implantable cardioverter-defibrillator (ICD) leads is safe in patients with cardiac vegetations, investigators report. And as long as blood cultures remain sterile, permanent devices can be reimplanted within a week or two.

Eradication of device-related infection requires complete system removal, the authors note in the March 2nd Journal of the American College of Cardiology. Traditionally, patients with vegetations larger than 1 cm in diameter have had their leads removed via thoracotomy, in order to avoid septic emboli -- but the surgery itself increases patients' risks for serious complications and for prolonged recovery.

Senior author Dr. Steven P. Kutalek and associates at Drexel University College of Medicine, Philadelphia, studied 100 patients (mean age, 67 years) who had 1838 leads extracted percutaneously despite echocardiographic evidence of vegetations. This group accounted for roughly 10% of all the percutaneous lead extraction cases at the authors' center between 1991 and 2007.

The vegetations ranged from 0.2 to 4.0 cm in largest diameter (mean 1.6 cm). Implants had been in place for an average of 51 months. The median extraction time (4 min per lead) was not significantly different from the median in a reference group consisting of all 66 patients without vegetations who underwent extraction in 2004.

Five patients had complications during lead extraction, including embolized vegetation in two. However, all 5 were discharged in stable condition and recovered uneventfully.

In 54 patients, surgeons reimplanted new devices during the same hospitalization, at a median of 7 days after extraction. None of these second devices had to be extracted due to relapsing infection.

Twenty-nine patients were lost to follow-up. In the remaining 71, the average follow-up was 438 days.

Nineteen patients died - 11 of persistent septicemia, 1 of sudden cardiac death, and the other 7 of unknown causes with no evidence of ongoing infection (including 4 who had received a new device).

Ten patients died within 30 days of lead extraction. "These unfortunate outcomes occurred in a critically ill subset of patients who often have extensive comorbidities," the researchers note. They attribute the operative mortality to disease severity rather than the mode of lead extraction.

Also, "given the frequent ambiguity of initial culture data," the authors recommend transesophageal ultrasonography before device extraction in order to identify patients at high risk for endocarditis.

This study demonstrates that "percutaneous lead extraction with vegetations of all sizes is possible and seemingly appropriate," Dr. James D. Maloney at Heartland Spine and Specialty Hospital, Overland Park, Kansas, and Dr. James D. Maloney III at the University of Wisconsin, Madison, write in a related editorial.

Still, they're concerned that residual infected inflammatory tissue needs to be debrided after the leads are removed.

"The question remains... if a nidus of chronic infection sometimes remains, does that cause refractory sepsis and congestive heart failure?" they ask. "Can and should it be removed surgically?"

Reference:
J Am Coll Cardiol 2010;55:886-897.

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Hybrid cardiology

2010-03-08T16:01:35+00:00

Richard J Shemin, MD, Chief of Cardiothoracic Surgery, UCLA David Geffen School of Medicine, discusses hybrid approaches to cardiology and cardiothoracic surgery, such as operation rooms where interventional cardiologists can work alongside cardiothoracic surgeons.

Reading:
Nollert G, Wich S. Planning a cardiovascular hybrid operating room: the technical point of view. Heart Surg Forum. 2009 Jun;12(3):E125-30.
Hu SS. One-stop hybrid approach for cardiovascular disease: from conception to practice. Ann Thorac Cardiovasc Surg. 2008 Dec;14(6):345-6.
Plass A, Schepis T, Scheffel H, Eberli F, Kaufmann P, Alkadhi H, Pretre R, Grünenfelder J. Multimodality preoperative planning and postoperative follow-up of a hybrid cardiac intervention. Heart Surg Forum. 2008 Dec;11(6):E375-7.

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Aspirin prophylaxis not useful for asymptomatic vascular disease

2010-03-05T21:36:50+00:00

NEW YORK (Reuters Health) – Asymptomatic patients with a low ankle brachial index don’t seem to get cardiovascular protection from aspirin, randomized trial results suggest.

The subjects came from a cohort of nearly 29,000 men and women ages 50 to 75 years enrolled in a community health registry in Scotland. All were free of clinical cardiovascular disease at baseline, and each agreed to ankle brachial index screening. The 3350 individuals with an index of no more than 0.95 took either 100 mg of aspirin daily, or placebo, for the next 8.2 years, on average.

In the Journal of the American Medical Association for March 3, lead author Dr. F. Gerald R. Fowkes, from the University of Edinburgh and colleagues report that 357 subjects met the main endpoint (a composite of coronary events, stroke, or revascularization). Rates per 1000 person-years were similar with aspirin (13.7) and placebo (13.3).

Rates of a secondary outcome – a composite of the main endpoint plus angina, intermittent claudication, or transient ischemic attack – were also comparable: 22.8 vs. 22.9 per 1000 person-years with aspirin vs placebo, respectively.

All-cause mortality was similar as well, with 12.8 deaths per 1000 person-years in the aspirin group and 13.5 in the placebo group.

Subjects treated with aspirin were 71% more likely than those given placebo to experience major hemorrhage requiring admission to the hospital: 2.5 vs. 1.5 per 1000 person-years.

“Based on the trial conducted by Fowkes et al and other similar studies, aspirin appears to have marginal benefits for reducing initial cardiovascular events when used for patients without clinically evident cardiovascular disease and is associated with higher rates of bleeding in these patients,” Dr. Jeffrey S. Berger, from New York University School of Medicine, comments in a related editorial.

Dr. Fowkes and colleagues conclude that “given the increased level of risk among those with a low ankle brachial index, the use of alternative therapies, such as statins or more potent antiplatelet agents without attendant hemorrhagic risks may usefully be considered.”

Reference:
JAMA 2010;303:841-848,880-882.

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Platelet function tests don’t predict PCI outcomes in low-risk patients

2010-02-26T17:12:18+00:00

NEW YORK (Reuters Health) – Baseline platelet function is only modestly related to ischemic outcomes after percutaneous coronary intervention (PCI) in low-risk patients, according to a study in more than 1000 patients. Moreover, common assays don’t accurately predict bleeding risk.

High platelet reactivity is known to increase patients’ risk for atherothrombotic events after PCI, and several assays are available for quantifying reactivity, the research team notes in the February 24th Journal of the American Medical Association.

In an attempt to identify the most accurate test, Dr. Jurrien M. ten Berg and colleagues at St. Antonius Hospital, Nieuwegein, the Netherlands, analyzed blood samples from 1069 low-risk patients on optimal clopidogrel and aspirin treatment, in advance of PCI and stent implantation.

They compared six different tests in subsets of patients:
-- Light transmittance aggregometry (n = 1051)
-- VerifyNow P2Y12 (Accumetrics) (n = 1052)
-- Plateletworks (Helena Laboratories) (n = 606)
-- IMPACT-R (Matis Medical Inc.) (n = 910)
-- Dade PFA-100 (Siemens Healthcare Diagnostics Products CmbH) (n = 812)
-- Innovance PFA P2Y (Siemens Healthcare Diagnostics Products CmbH) (n = 588)

The primary end point was a composite of all-cause death, acute myocardial infarction, ischemic stroke, and stent thrombosis. The primary safety outcome was major and minor bleeding. High platelet reactivity was based on a cut-off defined with receiver operating characteristic curve analysis.

During 1 year of follow-up, 18 patients died, 64 had nonfatal acute myocardial infarction, 14 had nonfatal ischemic strokes, 13 had definite stent thrombosis, and 3 had possible stent thrombosis. Thirty-three had major bleeding; 24 had minor bleeding.

When the authors constructed a model that would identify predictors for the primary endpoint, high platelet reactivity significantly improved the area under the curve only when measured by three of the methods: light transmittance aggregometry, the VerifyNow PsY12 assay, and the Plateletworks assay.

Specifically, rates of the primary end point in patients with and without high platelet reactivity were 11.7% vs 6.0% with light transmittance aggregometry (p < 0.001), 13.3% vs 5.7% with the VerifyNow PsY12 assay (p < 0.001), and 12.6% vs 6.1% with the Plateletworks assay (p = 0.005).

Still, Dr. ten Berg’s team notes, “the predictive accuracy of these tests was only modest.”

None of the tests could discriminate between patients with and without bleeding.

The investigators note that the sample size of the Innovance PFA P2Y, which became available halfway through the trial, was underpowered to detect a link between platelet reactivity and outcome, and other tests not available at the time were excluded. Also, patients were on 3 different clopidogrel regiments. “However, these 3 regimens are current clinical practices and our study therefore reflects the clinical relevance of monitoring platelet function in daily practice,” the authors add.

Until several ongoing clinical trials are completed, the authors maintain, “clinical practice should not be guided by (point-of-care) platelet function testing” for low-risk patients undergoing elective PCI.

Siemens Healthcare Diagnostics provided the Dade PFA and Innovance PFA P2Y for the study without charge.

Reference:
JAMA 2010;303:754-762.

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Pre-angio beta blockade contraindicated for many

2010-02-25T17:26:47+00:00

NEW YORK (Reuters Health) - Beta blockade before computed tomographic coronary angiography (CTA) can improve image quality, but a substantial number of patients who require CTA have contraindications to beta blockers, new research shows.

In the study from The Netherlands, patients who couldn't take beta-blockers were significantly less likely to have adequate heart rate control during CTA, and significantly less likely to have good-quality images - pointing to a need for other strategies to reduce heart rates during these procedures, the researchers say.

In patients undergoing CTA, beta blockade is routinely used to extend the diastolic interval and reduce heart rate variability, senior author Dr. Jeroen J. Bax of Leiden University Medical Center in The Netherlands and colleagues point out. But little is known about how many patients have contraindications to beta blocker use before CTA, as well as the efficacy of beta blockade in improving image quality.

To investigate, Dr. Bax and his team looked at 537 consecutive patients referred for CTA. Out of 283 patients (53%) with heart rates above 65 beats per minute, 237 received one dose of metoprolol an hour before CTA. In the remaining 46 patients, beta blockade was contraindicated.

In their online report February 8 in the American Journal of Cardiology, the authors note that contraindications included systolic blood pressure below 100 mm Hg, severe chronic obstructive pulmonary disease (COPD), aortic valve stenosis with valve area less than one square millimeter, ejection fraction below 35%, second- or third-degree atrioventricular block, and metoprolol allergy.

Patients with heart rates between 65 and 75 beats per minute received 50 mg metoprolol, while those with faster rates received 100 mg. Patients already taking up to 100 mg metoprolol daily, as well as those with less severe COPD, were considered to have relative contraindications to beta blockade and were given lower doses. Patients already taking more than 100 mg of metoprolol or another beta blocker were not given the medication before CTA.

Among the 237 patients given metoprolol, 26 received a lower dose than prescribed by the protocol due to contraindications. Of the 211 patients who did receive optimal beta blockade, 27% failed to achieve a target heart rate below 65, compared to 60% of the patients who didn't receive beta blockers.

The researchers also found that patients who didn't achieve optimal beta blockade were more likely to have exams with poor image quality (20% versus 6% for those who had optimal heart rate control), and less likely to have good image quality exams (40% versus 74%).

"Contraindications to beta blockade are present in a substantial proportion of patients," Dr. Bax and his colleagues write. "This results in suboptimal HR control and image quality, indicating the need for alternative approaches for HR reduction."

The researchers point out that even patients with normally slow heart rates sometimes need beta blockade during CTA, due to anxiety.

Reference:
Am J Cardiol 2010.

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