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Study also reveals most infections occur 2 weeks after surgery

Orlando – New research from the Perelman School of Medicine at the University of Pennsylvania has shown for the first time that pneumonia is the most common serious infection after heart surgery. The new study, presented at the 2011 American Heart Association Scientific Sessions, also revealed that most infections occur about two weeks after surgery, not one week as physicians previously thought.

“In the past, focus has been on sternal wound infections after heart surgery, rather than other prevalent infections such as pneumonia,” said Michael A. Acker, MD, the study’s lead researcher and chief of Cardiovascular Surgery at Penn. “This new research should help guide more effective management strategies to reduce overall occurrence of all infections.”

In the new study, researchers analyzed more than 5,100 patients in the Cardiothoracic Surgical Trials Network (CTSN). Patients, average age 64, were treated at nine U.S. academic medical centers and one Canadian center. The median time to major infection was 14 days after heart surgeries. Forty-two percent of all major infections occurred after hospital discharge.

“Half of these patients had no evidence of infection before they were discharged from the hospital,” Acker said. “Then they had to return because of the new infection. One implication is that patients must be followed more closely after discharge.”

In this study, which excluded patients who were infected before surgery, researchers found 761 infections: 300 were classified as major infections (occurring in 6 percent of patients) and 461 were minor (in 8.1 percent of patients). The most commonly performed procedures were isolated coronary artery bypass graft and aortic and mitral valve surgeries.

Several risk factors appeared to increase the risk of developing infection, including congestive heart failure, hypertension, chronic lung disease, corticosteroid use prior to surgery, and length of cardiopulmonary bypass time.

The study was funded, in part, by the National Heart, Lung, and Blood Institute (NHLBI), the National Institute of Neurological Disorders and Stroke (NINDS) at the National Institutes of Health (NIH), and the Canadian Institutes of Health Research (CIHR).

Heart bypass surgery is considered the gold standard for most patients with left main coronary artery disease, one of the most serious types of heart disease and one that affects thousands.

But a new UCLA study reports favorable long-term outcomes for lower-risk patients with this condition who underwent angioplasty with medication-coated stents, rather than bypass surgery.

A more minimally invasive procedure than surgery, angioplasty is performed by snaking a tiny wire up through an artery in the groin to the blocked area of the heart. The clogged artery is cleaned out, and a stent — a tiny wire-mesh tube — is placed in the artery to help keep it open, allowing blood to flow freely through the heart again.

Published in the June issue of the journal Catheterization and Cardiovascular Interventions, the study found that for patients with left main coronary artery disease who had normal artery function, the more minimally invasive procedure may be a safe and effective option.

“This is one of the first studies assessing the long-term outcomes of this procedure in lower-risk patients,” said Dr. Michael Lee, an assistant professor of cardiology at the David Geffen School of Medicine at UCLA.

According to Lee, current national guidelines recommend angioplasty with stenting only for patients who are poor candidates for surgery. He said that this may change in the future, if more studies like this one demonstrate the procedure’s effectiveness in a wider range of patients.

Researchers reviewed data, taken from an international registry, on 221 patients who had left main coronary artery disease with normal artery function. All patients had undergone

angioplasty with drug-eluted stents between 2002 and 2009 at one of four institutions. The average patient age was 68, and the majority were male.

Patients sought angioplasty with stenting instead of surgery for a number of reasons, including high surgical risk due to health issues like chronic obstructive pulmonary disease or a severely calcified artery, older age, or a preference for the more minimally invasive procedure.

“The study provided a window into “real-world” experience and is reflective of what is seen in everyday clinical practice,” Lee said.

In examining 30-day outcomes for patients in the study group, the team found no reports of cardiac death, stroke, re-clogging of the artery or blood clots forming related to the stent. Seven patients (3 percent) experienced a mild heart attack that can occur during the procedure. According to Lee, these are mild events with little long-term clinical impact.

Follow-up angiographs or heart images were available for 136 (62 percent) of the patients, which helped further track their heart health status.

At one year, the cumulative event-free survival rate for cardiac death was 97.7 percent, and the event-free rate for artery re-clogging was 92.9 percent.

Over the course of the study, 22 patients needed to be retreated due to the artery re-clogging, and this occurred mostly in the first year. Of those patients, 14 underwent a repeat angioplasty and eight had bypass surgery.

One of the most common side effects of angioplasty with stenting in the past has been the re-closing of the artery after treatment. Lee says that with drug-eluting stents, this is occurring less frequently.

“Our analysis found that the short-term outcomes were excellent,” he said. “Patients who survived after the first year had very good long-term survival and a low incidence of retreatment.”

At nearly four years, the event-free survival rate for cardiac death was 95.5 percent, and the event-free rate for re-clogging of the artery was 88.9 percent. Twenty of the 221 patients had died and nine deaths were cardiac-related.

“We found that this procedure had a low overall risk profile and may prove to be a viable alternative for this patient group,” Lee said.

Lee added that the next step would be a clinical trial comparing angioplasty with drug-eluting stents to coronary bypass surgery in this lower-risk patient population.

The study took place at four hospitals; they were located in Los Angeles and Santa Barbara in the U.S., and in Turin and Padua in Italy. The type of drug-eluting stents used in the study was at the discretion of the interventional cardiologist.

No outside funding was used in the study.

Newswise — Between 2001 and 2008, the annual rate of coronary artery bypass graft surgeries performed in the United States decreased by more than 30 percent, but rates of percutaneous coronary interventions (PCI; procedures such as balloon angioplasty or stent placement used to open narrowed coronary arteries) did not change significantly, according to a study in the May 4 issue of JAMA.

“Coronary revascularization, comprising coronary artery bypass graft (CABG) surgery and PCI, is among the most common major medical procedures provided by the U.S. health care system, with more than 1 million procedures performed annually,” according to background information in the article. Several innovations in coronary revascularization, such as drug-eluting stents (DES) and minimally invasive CABG surgery have been adopted widely in the past decade, with the promise of improved clinical outcomes compared with older revascularization technologies and techniques. “During this period of technological innovation, new published evidence, and updated guidelines, it is not well known whether or how the volume of coronary revascularization and its constituent types changed in the United States.

Substantial changes in the overall volume of revascularizations or the relative use of CABG surgery vs. PCI would have important ramifications on clinical outcomes, health care costs, and the future organization and delivery of hospital-based cardiovascular care.”

Andrew J. Epstein, Ph.D., of the Philadelphia Veterans Affairs Medical Center and University of Pennsylvania, Philadelphia, and colleagues conducted a study using a representative national sample of hospitalization claims to estimate trends in the annual volume of coronary revascularization procedures. The study included data on patients undergoing CABG surgery or PCIs between 2001 and 2008 at U.S. hospitals in the Healthcare Cost and Utilization Project’s Nationwide Inpatient Sample, which reports inpatient coronary revascularizations. These data were supplemented by Medicare outpatient hospital claims.

The researchers found that there was a 15 percent decrease in the annual rate of coronary revascularizations from 2001-2002 to 2007-2008. There was a substantial decrease in the rate of CABG surgery, with approximately one-third fewer CABG surgeries being performed in 2008 compared with 2001. The annual CABG surgery rate decreased steadily from 1,742 CABG surgeries per million adults per year in 2001-2002 to 1,081 CABG surgeries per million adults per year in 2007-2008, but PCI rates did not significantly change (3,827 PCI per million adults per year in 2001-2002 vs. 3,667 PCI per million adults per year in 2007-2008).

“Between 2001 and 2008, the number of hospitals in the Nationwide Inpatient Sample providing CABG surgery increased by 12 percent, and the number of PCI hospitals increased by 26 percent. The median (midpoint) CABG surgery caseload per hospital decreased by 28 percent and the number of CABG surgery hospitals providing fewer than 100 CABG surgeries per year increased from 23 (11 percent) in 2001 to 62 (26 percent) in 2008,” the authors write.

The researchers write that the findings of this study “suggest the possibility that several thousand patients who underwent PCI in 2008 would have undergone CABG surgery had patterns of care not changed markedly between 2001 and 2008. Our data imply a sizeable shift in cardiovascular clinical practice patterns away from surgical treatment toward percutaneous, catheter-based interventions.”

“In conclusion, although the total rate of U.S. coronary revascularization decreased modestly between 2001 and 2008, there was a substantial decrease in the CABG surgery rate. Between 2001 and 2008, the rate of PCI did not significantly change; however, there were continual changes in the frequency of stent types used for PCI.”

CHICAGO—Use of a radial artery (located within the forearm, wrist and hand) graft compared with a saphenous vein (from the leg) graft for coronary artery bypass grafting did not result in improved angiographic patency (the graft being open, unobstructed) one year after the procedure, according to a study in the January 12 issue of JAMA.

Coronary artery bypass grafting (CABG) is one of the most common operations performed, with a database indicating that in the United States, 163,048 patients had CABG surgery in 2008. The success of CABG depends on the long-term patency of the arterial and venous grafts. Arterial grafts are thought to be better conduits than saphenous vein grafts for CABG based on experience with using the left internal mammary (breast) artery to bypass the left anterior descending coronary artery, according to background information in the article. The efficacy of the radial artery graft, which is easier to harvest than other arteries, is less clear. A database shows that more than 10,000 patients in the United States received radial artery grafts in 2008, suggesting that about 6 percent of patients undergoing CABG have radial artery grafts.

Steven Goldman, M.D., of the Southern Arizona VA Health Care System and the University of Arizona Sarver Heart Center, Tucson, and colleagues compared 1-year angiographic patency of radial artery grafts vs. saphenous vein grafts in 757 participants (99 percent men) undergoing elective first-time CABG. The randomized controlled trial was conducted from February 2003 to February 2009 at 11 Veterans Affairs medical centers. The left internal mammary artery was used to preferentially graft the left anterior descending coronary artery whenever possible; the best remaining recipient vessel was randomized to radial artery vs. saphenous vein graft. The primary outcome measured was angiographic graft patency at 1 year after CABG. Secondary outcomes included angiographic graft patency at 1 week after CABG, heart attack, stroke, repeat revascularization and death.

The analysis included 733 patients (366 in the radial artery group, 367 in the saphenous vein group). The researchers found that there was no significant difference in 1-year graft patency between radial artery (238/266; 89 percent) and saphenous vein grafts (239/269; 89 percent). Also, there was no significant difference in 1-week patency between patients who received radial artery grafts (285/288; 99 percent) vs. saphenous vein grafts (260/267; 97 percent), or in the other secondary outcomes. There was no difference in the number and types of adverse events, including serious adverse events.

“Although most clinicians assume that compared with vein grafts, arterial grafts have an improved patency rate, there are little multi-institutional prospective data on radial artery graft vs. saphenous vein graft patency,” the authors write.

Because the important question is long-term patency, the researchers note that there will be a 5-year angiographic follow-up of these patients to define chronic graft patency in this population.
(JAMA 2011;305[2]:167-174.