SNOWMASS, COLO. (FRONTLINE MEDICAL NEWS) Isolated severe tricuspid regurgitation is a recently recognized, greatly underdiagnosed, and growing problem that’s treatable, provided affected patients are referred for surgery before the clinical course progresses to intractable right heart disease with cirrhosis and liver failure, Rick A. Nishimura, MD, said at the Annual Cardiovascular Conference at Snowmass.

“This is an emerging disease that you’re all going to see in your practices this year. You’ve got to know what to do with these patients. Get to them early,” urged Dr. Nishimura, professor of cardiovascular sciences and hypertension at the Mayo Clinic in Rochester, Minn.

The medical textbooks don’t discuss isolated severe tricuspid regurgitation (ISTR) or its etiology. ISTR is a disorder of progressive right ventricular dilation and dysfunction whose etiology involves either longstanding atrial fibrillation or valvular disruption due to interference from a crossing lead of a permanent pacemaker or implantable cardioverter defibrillator.

“This is something different. These patients have a normal left heart and left heart valves and normal pressures, with no pulmonary hypertension. So it doesn’t fit into any of the textbook categories of tricuspid regurgitation,” the cardiologist said.

Moreover, the current American College of Cardiology/American Heart Association guidelines on valvular heart disease don’t address ISTR, either. Physicians who attempt to apply the guidelines in deciding when to refer a patient with ISTR for surgery will oftentimes find they’ve waited too long and the patient has started to develop end-stage disease, according to Dr. Nishimura.

And he should know: He was lead author of the current ACC/AHA guidelines ( J Am Coll Cardiol. 2014 Jun 10;63[22]:2438-88 ).

Decades ago, Eugene Braunwald, MD, of Harvard Medical School, Boston, famously called the tricuspid valve “the forgotten valve.” The history of the Snowmass winter cardiology conference bears that out. During 2007-2017, the conference featured an average of 5.4 sessions per year on aortic valve disease, 4.5 sessions per year on mitral valve disease, and not a single session on tricuspid valve disease. But the tricuspid valve is forgotten no longer, Dr. Nishimura emphasized.

How ISTR presents

The affected patient has a history of either longstanding atrial fibrillation or a permanent pacemaker or ICD.

“This is something that 4 or 5 years ago people said didn’t exist. Our pacemaker people told me, ‘Nah, you can never get tricuspid regurgitation from our leads.’ Now it’s one of the leading causes of tricuspid regurgitation going to operation,” said Dr. Nishimura.

The presenting symptoms of ISTR are typically ascites, edema, and shortness of breath.

“Why should patients with a right heart problem get dyspnea? It turns out that when the right ventricle dilates it pushes the septum in, so the effective operative compliance of the left ventricle decreases and you actually see the pulmonary artery wedge pressure go up,” he explained.

On physical examination, the patient will have elevated jugular venous pressure with large V waves.

“This is a clue that something is going on. The patient will have neck veins jumping up to her ear lobes. The ear lobes are going to wiggle with every heart beat – boom, boom, boom. If you see that, you start to figure out what’s going on. You need nothing else,” Dr. Nishimura said.

The patient will likely also have a pulsatile enlarged liver and, even though this is valve disease, a murmur that’s either soft or inaudible.

Echocardiographic diagnosis

Echocardiography will show a dilated right ventricle and right atrium, a dilated inferior vena cava, and a normal left ventricle with no pulmonary hypertension. The classic sign of ISTR on continuous wave Doppler echocardiography is a dagger-shaped tricuspid regurgitation peak velocity signal of less than 2.5 meters/sec, which indicates the absence of pulmonary hypertension. This dagger shape occurs because the right atrial pressure equalizes the right ventricular pressure.

It’s also important to point the echo probe at the hepatic veins to spot another echocardiographic hallmark of ISTR: systolic reversal.

A thorough echo exam makes hemodynamic catheterization unnecessary in these patients, Dr. Nishimura added.

When to refer for tricuspid valve repair or replacement

The clinical course of ISTR is progressive, often rapidly so. It starts with elevated jugular venous pressure, then comes fatigue and shortness of breath, moving on to ascites and edema, then finally cirrhosis and renal failure. It’s a vicious cycle in which tricuspid regurgitation begets annular dilation, which causes chordal stretching and worsening tricuspid regurgitation, leading to further annular dilation.

Patients typically aren’t referred for surgery – and may not even present to a physician – until they’ve already developed end-stage disease. That’s probably why the outcomes of surgery for ISTR are so poor. Dr. Nishimura was senior investigator of a recent retrospective study of national trends and outcomes for ISTR surgery based on the National Inpatient Sample. The number of operations increased by 250% during a recent 10-year period, but the surgery is still rare: 290 operations in 2004, climbing to 780 nationwide in 2013.

In-hospital mortality remained steady over time at 8.8%, far higher than rates of in-hospital mortality for surgery for aortic and mitral valve disease, which today stand at 1%-2% or less. The adjusted risk of in-hospital mortality for tricuspid valve replacement in patients with ISTR was 1.9-fold greater than for valve repair ( J Am Coll Cardiol. 2017 Dec 19;70[24]:2953-60 ).

“I think the reason the operative risk of valve surgery for ISTR is so high is that we’re waiting until patients have end-stage disease,” Dr. Nishimura said.

Indeed, he recommends referral for surgery as soon as the echocardiographic diagnosis of ISTR is made in a patient with huge neck veins.

“This will probably take the operative risk down by going to a time when the right ventricle can still recover,” he added.

In a patient with ISTR and pacemaker or defibrillator leads crossing the valve, tricuspid valve repair or replacement should be accompanied by exteriorization of the leads.

Dr. Nishimura reported having no financial conflicts of interest regarding his presentation.