By Michael H. Crawford, MD, Editor

SYNOPSIS: A retrospective analysis of patients with moderate or severe tricuspid valve regurgitation (TR) and who underwent an earlier echo with no or mild TR showed that progression of TR was independently associated with age, female sex, new device leads, and right ventricular or tricuspid annular dilation.

SOURCES: Prihadi EA, van der Bijl P, Gursoy E, et al. Development of significant tricuspid regurgitation over time and prognostic implications: New insights into natural history. Eur Heart J 2018;39:3574-3581.

Carabello BA. The progression of tricuspid regurgitation: It seems capricious, or are we just too ignorant to understand it? Eur Heart J 2018;39:3582-3583.

Once moderate to severe tricuspid regurgitation (TR) has developed, patients are difficult to manage medically and invasive options to correct TR are limited. Prihadi et al analyzed the echocardiographic database of the university hospital in Leiden, Netherlands, for patients with moderate to severe TR to assess the factors promoting TR and the prognosis of rapidly developing TR. Patients with prior tricuspid valve surgery, active endocarditis, age < 18 years, and known congenital tricuspid valve abnormalities were excluded. The first 1,000 consecutive patients with moderate to severe TR who underwent an echo between 1991 and 2005 that showed no or mild TR comprised the study population.

Patients were divided into four groups based on the time between the older echo that showed no or mild TR and the more recent echo that showed moderate to severe TR: group 1 (fastest), group 2 (fast), group 3 (slow), group 4 (slowest). Clinical data on the patients were obtained retrospectively from the hospital information system for cardiology. Two investigators re-read all echoes and derived quantitative data. Tricuspid annulus diameter > 21mm/m2 in the four-chamber view was considered significant dilatation. TR severity was derived from a multimeasurement approach. Trace TR was considered no TR for the analysis. TR was classified as primary or organic if the tricuspid valve leaflets were damaged and secondary or functional if there was annular or RV dilatation. Device lead-associated TR was considered organic if there was no left heart disease. Isolated TR associated with atrial fibrillation was classified as functional.

On the first echo, 71% showed signs of mild TR and 29% no TR. After the second echo, 81% showed signs of moderate TR and 19% showed signs of severe TR. Only 5.8% of patients on the second echo showed signs of organic TR, most of which was device lead-related. Less than 1% of patients exhibited a primary leaflet abnormality. Group 1 developed significant TR in < 1.2 years, group 2 in 1.3-4.7 years, group 3 in 4.8-8.9 years, and group 4 in nine years. Group 1 patients were older, more likely female, and had more comorbidities.

Progression of TR was independently associated with age, device leads, mild or no TR, decreased right ventricular function, and increased tricuspid annulus diameter. Also, any left heart valve surgery between echoes was associated with fast TR progression. Survival rates were significantly lower in group 1 vs. the other groups and were independent of age and left and right ventricular systolic function. The authors concluded that perhaps by the identification of patients likely to develop moderate to severe TR by echo surveillance, earlier therapy application could reduce mortality rates.

COMMENTARY

For years, we believed that TR almost always was secondary to left heart disease or pulmonary hypertension and that effective treatment of these conditions would alleviate TR. Long-term follow-up of left heart valve surgery patients has shown that in some patients, TR did not improve; in others, such surgery improved TR initially, only to worsen later for inexplicable reasons. Also, we now see significant TR associated with device lead placement and chronic atrial fibrillation alone. These two causes represented 5.4% of the study population in this report. Thus, secondary TR still dominates. Until recently, there was little to do for these patients beyond treating the underlying pulmonary or left heart disease. Even after the underlying causes were treated, many patients still are quite symptomatic from their TR, and diuretic management of their venous congestion is challenging. Surgical tricuspid valve replacement is not attractive due to high reported mortality. Now that percutaneous devices designed to reduce or eliminate TR are in development (stented valves for the valve or cavae, valve clips), there is more interest in the earlier treatment of TR.

Prihadi et al addressed the issue of identifying patients who may benefit from earlier correction or abrogation of TR. Their retrospective analysis of factors that predicted rapid progression to moderate to severe TR showed that older age, female sex, a dilated tricuspid annulus (> 35mm), reduced right ventricular function, and subsequent left heart valve surgery independently predicted rapid development of significant TR. Also, the rapid development of significant TR was associated with all-cause mortality independent of age, right ventricular systolic pressure, and right or left ventricular function.

These data support the guideline recommendation to perform tricuspid valve annuloplasty during left heart valve surgery if moderate or more TR is present or the tricuspid annulus is enlarged. However, these data do not necessarily support interventions to abrogate TR in those likely to progress rapidly. This would have to be tested in a prospective trial. We do not know whether TR causes increased mortality directly or is just the canary in the mine. Until studies with the new devices for TR are conducted, we can follow patients with TR more closely, try to manage the likely underlying causes better, and treat any systemic venous congestion more aggressively.