EXPERT ANALYSIS FROM THE HEART VALVE SUMMIT 2016
CHICAGO (FRONTLINE MEDICAL NEWS) – Turning to surgery earlier in infective endocarditis may hold the key to a cure for some patients. Upcoming guidelines for surgical treatment of infective endocarditis lend evidence-based support to early surgical intervention in this high-mortality condition.
“Infective endocarditis is the most severe and potentially devastating complication for heart valve disease,” said Joseph Coselli, MD, in a presentation that reviewed current trends in incidence of infective endocarditis (IE) and laid out a rationale and strategy for early surgical intervention in some patients.
The bottom line? “Operate sooner rather than later,” said Dr. Coselli. “Once there’s an indication for surgery, operate. Leaky valves won’t become competent; disintegrated tissue will not regrow.” This requires something of a shift in mindset, he said. “Infective endocarditis is not a reason to postpone an operation otherwise indicated, but the opposite.”
“Untreated infective endocarditis is universally fatal,” said Dr. Coselli. Even with current treatments, however, overall mortality for infective endocarditis is 20%-25%, he said.
Speaking at the joint AATS-ACC Heart Valve Summit, Dr. Coselli , chief of the division of cardiothoracic surgery at Baylor College of Medicine, Houston, reviewed the key points in the upcoming guideline and the evidence that backs up the guidelines.
Dr. Coselli served on the writing committee for the 2016 AATS consensus guidelines for the surgical treatment of infective endocarditis; the guidelines are currently in press.
The guidelines propose that “at the time of surgery, the patient should be on an effective antimicrobial regimen to which the causative agent is sensitive,” he said. This is a level I recommendation, as is the recommendation that the surgeon should understand the pathology as well as possible before the procedure. Usually, say the guidelines, this is obtained by means of a transesophageal echocardiogram (TEE), assigning level I status to this recommendation as well.
According to the guidelines, patients with IE who may be surgical candidates during their hospitalization, regardless of whether their antimicrobial course is complete, include those who present with valve dysfunction that results in symptoms of heart failure. Surgery should also be considered in patients with left-sided IE with S. aureus, fungi, or other highly resistant organisms as the causative pathogen. If heart block, an aortic or annular abscess, or destructive penetrating lesions are present, surgery is also indicated. Finally, the guidelines recommend considering surgery if patients have persistent bacteremia or fevers at 5 to 7 days after initiation of appropriate antimicrobial therapy. All of these are class I indications in the upcoming guidelines, he said.
The patient who has relapsing infection, defined by the guidelines as recurrent bacteremia “after a complete course of appropriate antibiotics and subsequently negative blood culture,” who has no other identifiable source of infection, may also be a candidate.
Given the dearth of randomized trials in the area, no recommendation for intervention is backed by a level of evidence greater than B, said Dr. Coselli. And knowledge gaps persist in many areas, such as the appropriate timing of surgery in IE when there are neurological complications. Also, he said, “embolism risk needs to be better understood.” Imaging improvements would help guide decision-making, as would better data about contemporary rates of IE relapse and recurrence, said Dr. Coselli.
Though these surgeries should be done at centers that can field a complete team, and by experience valve surgeons, early intervention may be a key to success: “Operate before a devastating complication occurs,” said Dr. Coselli. “Understand what you see; don’t be afraid of radical debridement, and master alternative options to reconstruction” depending on the heart’s appearance in the OR, he said.
Surgeons can run into trouble in IE cases if they wait too long. “A patient who’s already had an embolic stroke may be too sick,” said Dr. Coselli. Insensitive organisms and ineffective antimicrobial therapy set the patient up for recurrent IE or treatment failure as well.
Having guidance for surgical intervention is important because cardiologists and surgeons will be seeing more infective endocarditis patients as heroin and other illicit intravenous drug use continues to rise, said Dr. Coselli. IE in intravenous drug users now accounts for up to 30% of all patients who seek treatment for IE, he said, citing a study that tracked characteristics of endocarditis patients undergoing surgery at a single institution from 2002-2014 ( J Thorac Cardiovasc Surg. 2016 Sep;152:832-41 ). Incidence in intravenous drug users can range to 2,000 cases per 100,000 patient-years, he said.
The study, conducted by Joon Bum Kim, MD, PhD, and his colleagues at Massachusetts General and Brigham and Women’s hospitals, both in Boston, followed 436 patients with IE, 78 of whom were intravenous drug users (IVDUs) at the time of diagnosis. Overall, the IVDUs were younger (mean age, 36 plus or minus 10 years) when compared with the non-IVDU group (mean age, 58 plus or minus 14 years; P less than 0.001). The non-IVDU cohort were also significantly more likely to have hypertension and diabetes, but less likely to smoke. However, IVDUs were more likely to have embolic events, and to have right-sided valve involvement.
Though early mortality was better in the IVDU group post-surgically, late complications, including reinfection and reoperation, were significantly more likely to occur in the IVDUs, with reinfection more than four times as frequent in IVDUs (aggregate valve-related complications, 41% in IVDUs vs. 10% in non-IVDUs; P = 0.001).
Despite the additional morbidity seen in IVDU-associated endocarditis, the 10-year survival rate was virtually identical between the two groups.
For many IE patients, said Dr. Coselli, “the arguments against surgery have lost strength.” Active systemic infections are treatable, sicker patients can be operated on earlier, and surgeons will gain experience with this sometimes technically challenging surgery, he said. Finally, Dr. Coselli said, even though the best available data support early surgical intervention in select IE patients, “final cure of IE is always the result of antimicrobial treatment and the patient’s own defense.”
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