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MAQUET Cardiovascular Receives FDA 510(k) Clearance and CE Mark for Its New Sensation Plus™ Intra-Aortic Balloon Catheter
MAQUET Cardiovascular announced that it has received both 510(k) clearance from the U.S. Food & Drug Administration (FDA) and CE mark approval from the British Standards Institution (BSi) for its new Sensation Plus™ 50cc 8 Fr. intra-aortic balloon catheter. The new Sensation Plus intra-aortic balloon (IAB) catheter is the first 50cc 8 Fr. IAB catheter to combine fiber optic signal acquisition with greater hemodynamic support compared to a standard 40cc IAB catheter.
“Clinicians have been asking for an IAB that combines all of the benefits of fiber optic technology; faster initiation of therapy, easier patient management and a crisp, clean arterial pressure wave form with increased hemodynamic support,” said Deb Joseph, Vice President, Marketing and Clinical Services. “We believe that the new, state-of-the art Sensation Plus™ intra-aortic balloon catheter meets these needs and will enable clinicians to provide patients with improved care.”
The new 50cc 8Fr. Sensation Plus IAB catheter provides greater patient support, comfort and ease of use than any IAB catheter MAQUET has ever offered. Sensation Plus incorporates fiber optic signal acquisition and provides 25 percent more blood volume displacement than standard 40cc IAB catheters, allowing for improved unloading and better augmentation. This new IAB catheter also comes with two Stat Lock® IAB stabilization devices which allow the catheter to be secured to the patient’s leg without sutures. This is more comfortable for patients and eliminates the risk of suture needle sticks for clinicians when initiating counterpulsation support. The new IAB catheter will be available for sale in October.
For more information about MAQUET Cardiovascular, please visit https://ca.maquet.com.
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Study Examines Use of Platelet Function Testing For Guiding Antithrombotic Treatment Before Procedures Such as Coronary Angioplasty and Stent Placement
Among patients with acute coronary syndromes undergoing a procedure such as angioplasty, those who received platelet function tests before receiving antithrombotic therapy to determine appropriate clopidogrel dosing and who had high residual platelet reactivity (platelets resistant to antithrombotic therapy) were at an increased risk of an ischemic event at short- and long-term follow-up of up to 2 years, according to a study in the September 21 issue of JAMA.
Several studies have shown that high residual platelet reactivity during clopidogrel treatment is predictive of major cardiovascular events in patients undergoing percutaneous coronary intervention (PCI). However, it has not yet been proven that the risk of thrombotic events increases markedly above a critical cut point of platelet reactivity on in vitro platelet function tests.
Guido Parodi, MD, and colleagues of Careggi Hospital, Florence, Italy, conducted a study to examine whether high residual platelet reactivity (HRPR) after clopidogrel loading is an independent prognostic marker of risk of long-term thrombotic events in patients with acute coronary syndromes (ACS) undergoing an invasive procedure and receiving long-term antithrombotic treatment adjusted according to the results of platelet function tests.
The study included 1,789 patients with ACS undergoing PCI from April 2005 to April 2009 and who had platelet reactivity assessed via testing. All patients received 325 mg of aspirin and a loading dose of 600 mg of clopidogrel followed by a maintenance dosage of 325 mg/d of aspirin and 75 mg/d of clopidogrel for at least 6 months. Patients with HRPR as assessed by adenosine diphosphate test (70 percent platelet aggregation or greater) received an increased dose of clopidogrel or switched to ticlopidine under adenosine diphosphate test guidance. The primary outcome measure was a composite of cardiac death, heart attack, any urgent coronary revascularization, and stroke at 2-year follow up. Secondary measured outcomes were stent thrombosis and each component of the primary endpoint.
The researchers found that the primary end point event rate was 14.6% (36/247) in the HRPR group and 8.7% (132/1,525) in the low residual platelet reactivity group (LRPR). The difference in the event rate was driven by the difference in cardiac mortality, which was 9.7% in the HRPR group and 4.3 percent in the LRPR group. The stent thrombosis rate was 2-fold higher in the HRPR group (6.1% [15/247] vs. 2.9% [44/1,525]). Additional analysis indicated that HRPR was independently associated with a 49% increased risk of the primary end point and a 81% increased risk of cardiac mortality.
The authors write that “the results of this study should be considered only as hypothesis generating for further studies of tailored therapy using new antithrombotic agents.”
Dominick J. Angiolillo, MD, PhD, of the University of Florida College of Medicine-Jacksonville, comments in an accompanying editorial on the use of platelet function testing.
“… despite promising research conducted to date, currently available evidence cannot support routine use of platelet function testing [PFT] in clinical practice. Until results of appropriately powered randomized controlled trials demonstrate efficacy and safety (in particular, low bleeding risk) of adjustment of antiplatelet treatment, PFT should be reserved mostly as a research tool.”
Source: JAMA 2011;306[10]: 1215-1223, 1260–1261.
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Research Review Finds Simulation an Effective Way to Train Health Care Professionals
An analysis led by Mayo Clinic researchers found that simulation-based training is an effective way to teach physicians, nurses, dentists, emergency medical technicians and other health professionals. The team reviewed more than 600 studies evaluating the use of technologies such as virtual reality computers, mannequins and training models to teach skills and procedures including surgery, trauma management, obstetrics and team communication. Their conclusions were published Sept. 7 in the Journal of the American Medical Association.
Lead author David Cook, MD, of Mayo Clinic’s Department of General Internal Medicine, worked with researchers from Mayo, the University of Ottawa, the University of British Columbia and the University of Toronto. They concluded that training with simulation is consistently better than no instruction, as measured in controlled settings and in practice with actual patients.
“We reviewed hundreds of articles, and, with extremely rare exceptions, we found improved outcomes for those who trained with simulation,” Dr. Cook says. “This held true across a wide variety of learners, learning contexts and clinical topics.”
However, “we need more effective, more efficient, and safer ways to learn,” Dr. Cook says, citing the increasing volume of medical knowledge, rapidly changing practice environments and evolving physician-patient relationships. “Simulation-based instruction has unique advantages, including the opportunity to practice without harming patients, repeat training to become more proficient and structure training for more effective learning.”
The study also found a lot of variation in the quality and results of the simulation activities. “Not all training was equally effective,” Dr. Cook says. “Now that we know that simulation works, the next step is to understand how to use simulation-based instruction effectively and efficiently.” He and the others on his team are currently researching how to use simulation-based teaching most cost-effectively.
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Emergency Treatment for Heart Attack Improving But Delays Still Occur
Despite improvements in treating heart attack patients needing emergency artery-opening procedures, delays still occur, particularly in transferring patients to hospitals that can perform the procedure, according to a study in Circulation: Journal of the American Heart Association.
“While we are making tremendous progress in PCI hospitals, delays are still occurring during the transfer process,” said Timothy D. Henry, MD, the study’s senior author and director of research at the Minneapolis Heart Institute Foundation at Abbott Northwestern Hospital in Minneapolis. “This is the first study that examines and identifies the specific reasons for delay of transfer patients.”
Researchers examined data from 2,034 STEMI patients transferred from 31 local non-PCI hospitals in Minnesota and Wisconsin to the Minneapolis Heart Institute from March 2003 to December 2009. Referring hospitals were up to 210 miles away from the Institute.
Despite long-distance transfers, 65.7 percent of patients were treated within120 minutes from the time of presentation at the initial referring hospitals.
However, 34.2% of patients experienced a delay in total treatment time, and the study found delays most frequently occurred at the referral hospital (64%), followed by the PCI center (15.7%) and during transport (12.6%).
Specifically, the 64% of delays at the referral hospital were caused by:
- Awaiting transportation—26%;
- Emergency department delays —14%;
- Diagnostic dilemma—9%;
- Initial negative test for heart attack—9%; and
- Cardiac arrest—6%.
Delays related to cardiac arrest were the most likely to result in death, with an in-hospital mortality rate of 31%. In contrast, some delays, like an initially negative heart attack test, had no increased risk of death.
“All delays are not created equally,” Henry said. “By identifying where the delays are we can improve the systems for transferring patients to get them the care they need.”
He said it’s important to recognize that the higher risk patients are faring the worst, so the less successful outcomes may be related to their advanced disease states.
In 2007, the American Heart Association launched Mission: Lifeline to help improve systems of care for STEMI patients by reducing barriers from the time 9-1-1 is called until hospital discharge. That includes lack of timely access to a hospital capable of performing angioplasty, 24 hours a day, seven days a week.
The American Heart Association also offers Mission: Lifeline Accreditation by the Society for Chest Pain Centers for hospitals meeting specific criteria as either a STEMI-receiving hospital or a STEMI-referral hospital.
“A study recently published in Circulation — ‘Improvements in Door-to-Balloon Time in the United States, 2005 to 2010’ — found that more than twice as many people are getting treatment within 90 minutes of arriving at an angioplasty hospital than were five years ago, so we are making great progress,” said Chris Granger, MD, chairman of the Mission: Lifeline steering committee and professor of medicine and director of the Cardiac Care Unit at Duke University Medical Center in Durham, N.C. “But Dr. Henry’s study shows us that many patients still have delays, and that certain types of delays are associated with worse outcomes. So there is an important opportunity to further improve care, especially for patients being transferred from hospitals not equipped to do angioplasty.”
“Our ultimate goal is to improve timely access to angioplasty in patients with STEMI,” Henry said. “We’ve been very successful doing this in hospitals that are equipped to provide the procedure. This study emphasizes that now our focus should be on regional systems which seek to incorporate those hospitals that require patient transfer in the process.” The Minneapolis Heart Institute Foundation funded the study.
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Stents May Reduce Heart Attacks by Delivering Downstream Medication
Researchers at Cleveland Clinic have discovered that cardiac patients receiving drug-eluting stents have a lower likelihood of suffering heart attacks or developing new blockages in the vessel downstream from the stent.
The recent study, led by Richard Krasuski, MD, Director of Adult Congenital Heart Disease Services and a staff cardiologist in the Section of Clinical Cardiology in the Department of Cardiovascular Medicine at the Miller Family Heart & Vascular Institute at Cleveland Clinic, suggests that drug-eluting stents may deliver the medication to the vessel beyond the stent.
In a study recently published in the American Heart Journal, Dr. Krasuski and his colleagues demonstrate that patients receiving drug-eluting stents have a lower likelihood of suffering heart attacks or developing new blockages in the vessel downstream from the stent.
“Though there have been concerns about clots forming inside drug-eluting stents, the totality of data suggests that patients receiving drug-eluting stents do better than patients receiving bare metal stents,” Dr. Krasuski said. “It has not been clear before, however, why preventing re-blockage in the location of a stent would have such a large benefit, but our study suggests that there may be more that the stent is doing. When blood flows through the stent, medication not only reaches the vessel it is touching, but likely the distal vessel as well. In this way it could be having a much more profound effect on the vessel.”
If this concept is confirmed, it could revolutionize treatment of cardiovascular disease and problems with other organ systems as well. Stents could be altered to deliver many different medications in small amounts directly to the blood vessels. This could maximize the benefits of different drugs and reduce their toxic effects, as well as improve patient compliance.
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Boston Scientific Launches Coyote™ Balloon Catheter for Peripheral Angioplasty Procedures
Boston Scientific Corporation has launched its Coyote™ Balloon Catheter, a deliverable and ultra-low profile 0.014-inch balloon dilatation catheter designed to treat patients undergoing peripheral angioplasty procedures below the knee. The Company has begun marketing the product in the U.S., Europe and other international markets.
Boston Scientific developed the Coyote Balloon Catheter to help physicians better treat patients with challenging obstructive lesions in the lower extremities. It features an ultra-low lesion entry profile (0.017-inch), excellent crossing profile and a shaft optimized for outstanding deliverability. The balloon offers rapid deflation times and is available in lengths up to 220 mm on both over-the-wire (OTW) and monorail platforms.
Coyote is the latest in a series of balloon catheter products introduced by Boston Scientific. In June, the Company launched its Mustang™ PTA Balloon Catheter, a deliverable 0.035-inch percutaneous transluminal angioplasty (PTA) catheter designed for a wide range of peripheral angioplasty procedures.
For more information, please visit: www.bostonscientific.com.
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Predicting Perilous Plaque in Coronary Arteries Via Fluid Dynamics
Researchers at Emory and Georgia Tech have developed a method for predicting which areas of the coronary arteries will develop more atherosclerotic plaque over time, based on intracoronary ultrasound and blood flow measurements.
The method could help doctors identify “vulnerable plaque,” unstable plaque that is likely to cause a heart attack or stroke. It involves calculating shear stress, or how hard the blood tugs on the walls of the arteries, based on the geometry of the arteries and how fast the blood is moving.
The results were posted online in the journal Circulation, published by the American Heart Association. The lead author is Habib Samady, MD, professor of medicine and director of interventional cardiology at Emory University School of Medicine.
Most people who have heart attacks do not have plaques in their arteries that bulge out and obstruct blood flow beforehand. Instead, the plaques in their arteries crack and spill open, leading to a clot. Samady says his team’s ultimate aim is to try to figure out where that will happen.
Cardiology researchers studying arteries in isolation or in animals have long seen a link between branches in the arteries, disturbances in blood flow, and where atherosclerosis develops. The challenge was to translate observations from the laboratory to imaging the heart within a live person, he says.
“It’s like looking at a river and predicting where sediment will accumulate,” he says. “It sounds obvious, but it’s hard to do it for every nook and cranny in the coronary arteries.”
The Emory/Georgia Tech study was the largest published investigation of shear stress and plaque progression in humans so far, and the first to examine people with significant coronary artery disease. Doctors examined 20 patients in Emory University Hospital’s catheterization laboratory between December 2007 and January 2009. They were being examined because they had abnormal exercise EKGs or stable chest pain. The patients’ coronary arteries were examined by intracoronary ultrasound and Doppler guide wire before and after six months of therapy with atorvastatin (Lipitor).
To model shear stress, Samady, assistant professor Michael McDaniel, MD, and postdoctoral fellow Parham Eshtehardi, MD, teamed up with Jin Suo and Don Giddens, experts in fluid mechanics at Georgia Tech. The patients’ arteries were divided into more than 100 segments each, and the shear stress was calculated for each one. Ultrasound allowed the researchers to estimate the size and composition of the plaques in each segment before and after the six-month period.
“Some atherosclerotic plaque appears to develop in a steady progression, and in other places, it develops in fits and spurts. These areas exist within the same patient and the same artery,” Samady says. “Our thinking is that the places where plaque develops in more fits and spurts may lead to the rupture of plaque, leading to a clot that blocks blood flow. In contrast, the places where you have steady progression may be more stable, as long as there is a fibrous covering that is thick enough.”
Analyzing each segment, the overall area of the plaque increased and the core of the plaque grew larger in places where shear stress was especially low. In places where the shear stress was high, there was shrinking of the fibrous covering of the plaque and expansion of lipid necrotic core and dense calcified areas.
“High shear stress leads to regression, which you might think is good, but there are some bad actors that may lead to plaque rupture,” he says. “What’s new here is that we’re seeing the detrimental effects of both low and high shear stress.”
The data also shows that arterial plaques can grow despite anti-cholesterol therapy with statins, the current standard of care. To really gauge whether plaque in a certain spot is going to be dangerous, Samady says doctors would need to look at outcomes in more patients over a longer time frame.
“The dream is to predict which spot is vulnerable, and use that to guide treatment with drugs and interventions like stents,” he says. For the present, the shear stress-based method can be used to monitor patients’ progress and determine how well treatment is working. Samady says ultrasound and blood flow measurements could be combined with a newer technique called optical coherence tomography for better resolution and more information.
The research was supported by the Wallace H. Coulter Foundation, Pfizer Inc., and Volcano Therapeutics.
Reference
- Samady H, Eshtehardi P, McDaniel MC, et al. Coronary artery wall shear stress is associated with progression and transformation of atherosclerotic plaque and arterial remodeling in patients with coronary artery disease. Circulation 2011 Aug 16;124(7):779–788.
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Possible New Blood Test to Diagnose Heart Attacks
Loyola University Chicago Stritch School of Medicine researchers are reporting a possible new blood test to help diagnose heart attacks. In the Journal of Molecular and Cellular Cardiology, researchers report that a large protein known as cardiac myosin binding protein-C (cMyBP-C) is released to the blood following a heart attack.
“This potentially could become the basis for a new test, used in conjunction with other blood tests, to help diagnose heart attacks,” said senior author Sakthivel Sadayappan, PhD. “This is the beginning. A lot of additional studies will be necessary to establish cMyBP-C as a true biomarker for heart attacks.”
Sadayappan is an assistant professor in the Department of Cell and Molecular Physiology at Loyola University Chicago Stritch School of Medicine. First author is Suresh Govindan, PhD, a postdoctoral researcher in Sadayappan’s lab.
Between 60-70% of all patients who complain of chest pain do not have heart attacks. Many of these patients are admitted to the hospital, at considerable time and expense, until a heart attack is definitively ruled out.
The Loyola study is the first to find that cMyBP-C is associated with heart attacks. The protein is specific to the heart. And it may be readily detectable in a blood test because of its large molecular size and relatively high concentration in the blood.
Researchers evaluated blood samples from heart attack patients. They also evaluated rats that had experienced heart attacks. They found that in both humans and rats, cMyBP-C was elevated significantly following heart attacks.
Sadayappan said cMyBP-C is a large assembly protein that stabilizes heart muscle structure and regulates cardiac function. As heart cells die, cMyPB-C breaks into fragments and is released into the blood.
“Future studies,” Sadayappan and colleagues wrote, “would determine the time course of release, peak concentrations and half life in the circulatory system.”
The study was supported by grants from the National Institutes of Health and American Heart Association.
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Psoriasis Patients Face Higher Than Average Death Risk After a Heart Attack
Heart attack patients with psoriasis are 26% more likely to die from cardiovascular disease, or suffer from recurrent heart attacks or strokes, and are 18% more likely to die from all causes than those without the inflammatory skin disease. That’s the key finding of a Danish study published in the September issue of the Journal of Internal Medicine.
Researchers studied nearly 50,000 patients who had experienced their first heart attack between 2002 and 2006, following the 462 patients with psoriasis for an average of 19.5 months and the 48,935 controls for an average of 22 months.
They found that the patients with psoriasis had higher all-cause and specific death rates and say this indicates the need for a more aggressive approach to secondary prevention of cardiovascular disease in this group of patients.
“Psoriasis is a common skin condition that is estimated to affect 125 million people worldwide,” explains lead author and cardiologist Dr. Ole Ahlehoff, from Copenhagen University Hospital Gentofte.
“It is a chronic inflammatory condition where the skin cells we naturally shed all the time are replaced much quicker than normal, leading to a build up of psoriatic plaque. Heart attacks are also caused by a build-up of plaque, in the arteries leading to the heart. Our study explored the links between the two conditions, which appear to have similar inflammatory mechanisms.”
Key findings of the study included:
- The incidence rates per 1,000 patient years for all-cause deaths were 16% higher for those with psoriasis (138.3 versus 119.4) and the adjusted hazard ratio was 1.18 (18% higher).
- The incidence rates per 1,000 patient years for deaths for a composite of cardiovascular death, recurrent heart attacks or stroke were 24% higher for those with psoriasis (185.6 versus 149.7) and the adjusted hazard ratio was 1.26 (26% higher).
- Baseline measurements showed that patients with psoriasis had a higher rate of hospitalization for stable and/or unstable angina. They also showed that a higher percentage of patients with psoriasis were treated with statins and ACE inhibitors/angiotensin 2 receptor blockers.
- Patients with psoriasis who survived their first heart attack were more likely to receive statin therapy than those without psoriasis. However, the presence of other health issues, and the differences in clinical management, did not explain the worsened prognosis in patients with psoriasis.
“To our knowledge, this is the first study to assess the prognosis in patients with psoriasis following a heart attack,” says Dr. Ahlehoff. “Our findings show that people with psoriasis demonstrated a significantly increased risk of recurring adverse cardiovascular events and a trend for increased all-cause deaths after a heart attack.
“Furthermore, the poor prognosis faced by psoriasis patients who have had a heart attack suggests the need for a more aggressive approach to secondary prevention of cardiovascular disease in this group of patients.”
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CT Imaging Better Than Stress Testing in Chest Pain Diagnosis
A multi-center trial initiated and coordinated at Beaumont Health System in Royal Oak, Michigan, shows that computed tomography heart imaging is accurate, faster and less costly than nuclear cardiology stress testing when diagnosing low-risk chest pain patients in the Emergency Center.
The research is published in the Sept. 26 issue of the Journal of the American College of Cardiology.
Emergency departments typically rely on a patient history, a series of EKGs and biomarker blood testing to diagnose “low risk” patients. This approach has resulted in the discharge of 2 percent of patients who were later diagnosed with acute heart attack who have a higher mortality rate as a result.
To avoid this problem, many emergency departments now use “rule out” protocols for low-risk patients that include cardiac stress testing and/or CT heart imaging. While more accurate, this is time consuming and expensive — with costs estimated at $10 to $12 billion annually in the U.S. alone.
In the Beaumont study, lead investigators Gilbert Raff, MD, director, Ministrelli Center for Advanced Cardiovascular Imaging, and James Goldstein, MD, director, cardiology research and education, looked at the accuracy and speed of cardiac CT versus nuclear stress testing for low-risk chest pain evaluation.
“At a time when economic resources are constrained, while health care demand is increasing, it is important to compare the effectiveness of diagnostic methods not only for safety and accuracy, but for efficiency and cost,” says Dr. Goldstein, professor of medicine with the Oakland University William Beaumont School of Medicine. “Consumers and insurers want high-value care that’s high quality at an affordable cost.”
The study, called CT-STAT (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain) found that use of CT imaging for low-risk chest pain diagnosis was more rapid and less costly than rest-stress testing.
“CT angiography was 54% faster in diagnosis and 38% less expensive in terms of overall cost of emergency care with no difference in adverse cardiac events,” says Dr. Raff. “The median cost of CT imaging was $2,137 versus $3,458 for stress testing.”
The study, conducted June 2007 – November 2008, involved 749 patients at 11 university and five community-based hospital emergency rooms in eight states. It was supported by a grant from Bayer HealthCare, Berlin, Germany.
“This research builds on our earlier findings (Journal of the American College of Cardiology, Feb. 2007),” says Dr. Goldstein. “Further studies will help us to optimize the use of coronary CT versus other diagnostic methods (ECG, stress testing, echocardiography) for specific types of patients.”
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Genetics More Important to Coronary Heart Disease Risk Than Family Lifestyle, Study Shows
It has long been known that hereditary factors play a role in coronary heart disease. However, it has been unclear whether the increased risk is transferred through the genes or through an unhealthy lifestyle in the family. A new study from the Center for Primary Health Care Research in Sweden, published in the American Heart Journal, shows that genes appear to be most important.
The researchers, led by Professor Kristina Sundquist, studied people who had been adopted and compared them with both their biological and their adoptive parents. The Swedish multi-generation register and the in-patient care register were used to follow 80,214 adopted men and women. They were all born in 1932 or later and developed coronary heart disease between 1973 and 2008. Using the registers, the researchers also studied the adoptive parents and biological parents over the same period.
The risk of coronary heart disease in adopted individuals who had at least one biological parent with coronary heart disease was 40-60% higher than that of a control group. There was no increased risk in individuals whose adoptive parents suffered from coronary heart disease, not even if both adoptive parents had the disease.
“The results of our studies suggest that the risk of coronary heart disease is not transferred via an unhealthy lifestyle in the family, but rather via the genes,” says Kristina Sundquist, a professor at the Center for Primary Health Care Research in Malmö, Sweden.
“But that does not mean that one’s lifestyle is not a factor in one’s own risk of developing coronary heart disease.”
Reference
- Sundquist K, Winkleby M, Li X, et al. Familiar transmission of coronary heart disease: A cohort study of 80,214 Swedish adoptees linked to their biological and adoptive parents. Am Heart J 2011:162(2):317, doi: 10.1016/j.ahj.2011.05.013.
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Cardiac Rehabilitation Improves Heart Rate Recovery, Boosts Survival
For the first time, researchers have discovered cardiac rehabilitation can train the heart to quickly return to its normal rate after exercise.
In a study reported in Circulation: Journal of the American Heart Association, researchers said heart disease patients with normal heart rate recovery live longer than those with slow heart rate recovery. A heart that returns to normal rate more quickly works better than one that stays revved up for a while.
“There’s no medicine that can do that,” said Leslie Cho, MD, lead author of the study and director of the Women’s Cardiovascular Center at the Cleveland Clinic in Ohio. “Especially in terms of mortality, if we had a medicine that could make this dramatic an impact, it would be the blockbuster drug of the century.”
Researchers looked at 1,070 patients with various cardiovascular diseases who were referred for cardiac rehabilitation at the Cleveland Clinic. They measured heart rate recovery with an exercise stress test before and after 12 weeks of cardiac rehabilitation. A count of 12 beats or less was considered abnormal.
Among the 544 patients who started cardiac rehabilitation with abnormal heart rate recovery, 41 percent had normal heart rate recovery after 12 weeks. Of the 526 patients who started with normal heart rate recovery, 89 percent maintained it after cardiac rehabilitation.
The risk of dying within eight years more than doubled in patients whose heart rate recovery was abnormal after cardiac rehabilitation, even after adjusting for factors such as smoking history, weight and changes in the use of medications.
“There’s not only mortality benefit from cardiac rehabilitation, but now we know why people benefit,” said Cho, who is also section head of preventive cardiology and rehabilitation in the Department of Cardiovascular Medicine at the Cleveland Clinic.
Cardiac rehabilitation consisted of physician-supervised exercise, typically three times a week, which included 10-15 minutes of warm-up and stretching, 30-50 minutes of continuous aerobic activity and 15-20 minutes of cool-down.
Only 10 percent to 20 percent of candidates for cardiac rehabilitation participate in structured exercise programs, Cho said.
“Cardiac rehabilitation is the most underused treatment in America,” Cho said. “Not enough doctors are recommending it to patients. Even when a recommendation is made, patients aren’t informed that cardiac rehabilitation can help them live longer.”
“It’s really important to encourage our patients to participate in structured exercise — not just telling the patient to go exercise and do your best and good luck.”
Patients in the study who didn’t improve their heart rate recovery tended to be older, with a history of diabetes, peripheral artery disease and congestive heart failure.
Further research is needed to determine whether continuing cardiac rehabilitation for an additional 12 weeks can bring heart rate recovery into the normal range for these patients, Cho said.
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Possible Cardiovascular Risk Found With NSAID Use, Swine Study Suggests
A new study from Rhode Island Hospital researchers suggests that controlling cholesterol may be important for heart health in patients who are taking non-steroidal anti-inflammatory drugs (NSAIDs) such as naproxen. The findings are based on a study on the safety of NSAID medications in clinically relevant animal models when high cholesterol is a factor. The study is published in the current issue of the journal Surgery.
NSAIDs are among the most widely-used drugs today for the treatment of post-operative pain, inflammatory conditions and fever. Despite that, the factors that affect their cardiovascular safety are not well understood and some studies suggest that there may be an increased incidence of cardiovascular complications such as heart attack or death.
This study, led by principal investigator Frank Sellke, MD, chief of cardiothoracic surgery and research at Rhode Island Hospital, developed an animal model of hypercholesterolemia in swine to investigate the formation of collateral vessels and other effects in the heart, and the safety of NSAID and other medications.
Through their study, Sellke says, “We found that a high-cholesterol diet reduced blood flow to the heart muscle in our animal models with chronic heart disease when given daily naproxen. We also found reduced levels of prostacyclin, a compound that dilates blood vessels and prevents blood clots. These findings suggest that there may be a stronger risk of negative effects on the heart in patients who have high cholesterol levels and are taking NSAIDs as a form of pain or inflammation relief.”
The researchers compared two groups within the animal model, one with a normal diet, and one group that received a diet high in cholesterol, and both groups received daily naproxen. The animals also underwent surgery to simulate coronary artery disease, which affects many human patients who take NSAIDs. Several differences were found between the two groups.
Compared to animals with normal cholesterol, the high-cholesterol animals treated with naproxen had lower blood flow to the heart, decreased levels of prostacyclin, and decreased levels of several proteins that promote cardiac cell survival. In addition, previous studies by the group showed that while naproxen helped increased blood flow in the hearts of animals with normal cholesterol, this effect was not seen in animals with high cholesterol.
Sellke says, “These results show that high blood cholesterol levels change the way naproxen affects the heart, and alters blood flow to the heart. This ‘myocardial perfusion’ may be one predictor of angina frequency and quality of life in patients with chronic ischemia. Thus, these findings may have important implications for cardiac patients taking NSAIDs.”
First author Louis Chu, MD, who worked with Sellke on the study, adds, “Our study indicates that physicians should be aware that cholesterol control may be especially important if patients are taking NSAID medications such as naproxen.”
Sellke adds, “While the results of these animal experiments are interesting and may provide information regarding the effect of a high fat diet on the response to naproxen and other similar medications, one cannot make definitive statements on the effect of these medications on patients without first doing clinical studies.”
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Researchers Create First Human Heart Cells That Can Be Paced With Light
In a compact lab space at Stanford University, Oscar Abilez, MD, trains a microscope on a small collection of cells in a petri dish. A video recorder projects what the microscope sees on a nearby monitor. The cells in the dish pulse rhythmically, about once a second. The cells are cardiomyocytes, which drive the force-producing and pacemaker functions of the human heart. They are programmed to pulse. They will beat this way until they die.
Abilez holds up a finger as if to say, “Wait,” and reaches for a small lever hidden behind the microscope. With the same finger, he flips the lever up. A pale, blue light floods the petri dish. Abilez flicks the light off and then on; first fast and then slow. Each time his finger goes up, the heart cells contract in concert with the light.
In a paper published Sept. 21 in the Biophysical Journal, lead author Abilez, a postdoctoral scholar and PhD candidate in bioengineering, and a multidisciplinary team from Stanford describe how they have for the first time engineered human heart cells that can be paced with light using a technology called optogenetics.
In the near term, say the researchers, the advance will provide new insight into heart function. In the long term, however, the development could lead to an era of novel, light-based pacemakers and genetically matched tissue patches that replace muscle damaged by a heart attack.
To create the light-responsive heart cells, the researchers first inserted DNA encoding a light-sensitive protein called channelrhodopsin-2, or ChR2, into human embryonic stem cells. ChR2 controls the flow of electrically charged ions into the cell. For heart cells, the primary ion is sodium, which initiates an electrochemical cascade that causes the cell to contract. They then transformed the optogenetically-engineered stem cells into cardiomyocytes unlike any others — those that respond to light.
Like the new heart cells, optogenetics is a product of Stanford. Bioengineer and psychiatrist Karl Deisseroth, MD, PhD, a co-author of the new study, has played a key role in the technology’s development. It is an increasingly common research technique that allows researchers to fashion all manner of mammalian tissues that are responsive to light.
While Deisseroth has focused his research primarily on neurons in order to study neurological illnesses ranging from depression to schizophrenia, Abilez is the first to create optogenetic human heart cells.
The all-important protein for the experiment is ChR2, which is sensitive to a very specific wavelength of blue light and regulates tiny channels in the cell surface. When ChR2 is illuminated by the right wavelength of blue light, the channels open to allow an influx of electrically charged sodium into the cell, producing a contraction.
After creating the cells in a laboratory dish, Abilez next turned to Ellen Kuhl, PhD, the study’s senior author and an associate professor of mechanical engineering, whose specialty is sophisticated computer modeling of the human body.
Using her algorithms, they tested their new cells in a computer simulation of the human heart, injecting the light-sensitive cells in various locations in the heart and shining a virtual blue light on them to observe how the injections affected contraction as it moved across the heart.
“In a real heart, the pacemaking cells are on the top of the heart and the contraction radiates down and around the heart,” Kuhl explained. “With these models we can demonstrate not only that pacing cells with light will work, but also where to best inject cells to produce the optimal contraction pattern.”
The long-term goal is a new class of pacemakers. Today, surgically implanted electrical pacemakers and defibrillators are commonplace, regulating the pulses of millions of faulty hearts around the globe.
“But neither is without problems,” said Abilez. “Pacemakers fail mechanically. The electrodes can cause tissue damage.”
“Defibrillators, on the other hand,” Kuhl said, “can produce tissue damage due to the large electrical impulses that are sometimes needed to restore the heart’s normal rhythm.”
The researchers foresee a day when bioengineers will use induced pluripotent stem cells fashioned from the recipient’s own body, or similar cell types that can give rise to genetically matched replacement heart cells paced with light, circumventing the drawbacks of electrical pacemakers.
“We might, for instance, create a pacemaker that isn’t in physical contact with the heart,” said co-author Christopher Zarins, MD, professor emeritus of surgery and director of the lab where Abilez performed the experiments. “Instead of surgically implanting a device that has electrodes poking into the heart, we would inject these engineered light-sensitive cells into the faulty heart and pace them remotely with light, possibly even from outside of the heart.”
The leads for such a light-based pacemaker might be placed outside the heart, but inside the pericardium. Or, someday, the researchers say, there might be a pacemaker placed inside the heart chambers, as with traditional pacemakers, whose light can travel through the intervening blood to pace light-sensitive heart cells implanted inside.
“And, because the new heart cells are created from the host’s own stem cells, they would be a perfect genetic match,” Abilez added. “In principle, tissue rejection wouldn’t be an issue.”
“Much work and many technical hurdles remain before this research might lead to real-world application,” said Zarins. “But, it may one day lead to more reliable, less invasive devices.”
In the near term, however, the advance is promising on other fronts, said Abilez.
“Optogenetics will make it easier to study the heart. Not only can researchers turn cells on with light, but off as well,” Abilez said.
Scientists might use these tools to induce disease-like abnormalities and arrhythmias in sample tissues in order to better understand how to fix them. There are likewise advantages inherent in pacing with light versus electricity.
“Heart researchers are often seeking to measure electric response in the heart,” said Abilez, “but it takes quite a lot of electricity to stimulate the heart and the resulting electrical signal is relatively weak. This makes it hard to distinguish stimulus from response. It’s like trying to hear a whisper in a crowded room.” Pacing with light would eliminate that challenge.
Optogenetics could lead to advances beyond the heart, as well, the authors concluded in their study. It might lead to new insights for various neuronal, musculoskeletal, pancreatic and cardiac disorders, including depression, schizophrenia, cerebral palsy, paralysis, diabetes, pain syndromes and cardiac arrhythmias.
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Diabetics’ Coronary Calcium Levels Strongly Linked to Heart Attack Risk
Notable levels of calcium buildup in coronary arteries can be strong predictors of heart attacks and strokes in people with diabetes and metabolic syndrome, according to a study led by the University of California Irvine’s (UCI) Heart Disease Prevention Program.
The researchers also found that individuals with diabetes or metabolic syndrome but no evidence of coronary calcium had cardiac-event risks as low as many without these conditions.
Supported by the National Institutes of Health, the multiethnic study of atherosclerosis involved 6,600 people ages 45 to 84. About 16 percent were diabetic (primarily type 2); another 25 percent had metabolic syndrome, a combination of disorders that can lead to cardiovascular disease and diabetes.
The researchers wanted to know whether information from a heart scan for coronary calcium or an ultrasound of the neck’s carotid artery could supplement standard factors — high cholesterol, smoking, elevated blood pressure — in assessing a person’s chance of heart attack or stroke.
“Our study points out that there’s a wide range in risk for cardiovascular consequences seen in persons with metabolic syndrome and diabetes and that screening of coronary calcium by heart scans — and, to a lesser extent, carotid arteries by ultrasound — may be helpful in picking out those most vulnerable,” said Nathan Wong, UCI professor of medicine, director of the Heart Disease Prevention Program and senior author of the study.
“Our findings also suggest that individuals with significantly high levels of coronary calcium or carotid wall thickness should receive more aggressive monitoring and treatment for any associated risk factors,” added co-author Dr. Shaista Malik, a UCI cardiologist.
These observations are consistent with guidelines released last year by the American Heart Association and American College of Cardiology recommending such screenings for diabetics 40 and older without known cardiovascular disease, as well as many people with metabolic syndrome.
