Analysis of the amount of tricuspid valve anular dilatation required to produce functional tricuspid regurgitation.

To determine the critical anular dilatation required for functional tricuspid regurgitation (TR) and the role of systolic anular shortening in the severity of TR, 67 patients in whom right ventriculography had been performed were studied. These patients were classified into group I, control (n = 12), and the group II, patients with rheumatic valvular disease (n = 55). Group II patients were subclassified as follows: IIa, without TR (n = 19); IIb, with mild TR (n = 22); and IIc, with moderate to severe TR (n = 14). The angiographic maximal early systolic and minimal end-systolic diameters were measured. The shortening of the tricuspid anulus was expressed as percent reduction of the maximal diameter. The average maximal diameter (mm/m2) was: group I, 21 +/- 2; group IIa, 24 +/- 2; group IIb, 31 +/- 4; and group IIc, 37 +/- 4. The average minimal diameter (mm/m2) was: group I, 15 +/- 2; group IIa, 18 +/- 2; group IIb, 23 +/- 2; and group IIc, 31 +/- 3. The average percent shortening was: group I, 30 +/- 7%; group IIa, 25 +/- 7%; group IIb, 26 +/- 5%; and group IIc, 15 +/- 3%. The rheumatic patients had a larger maximal diameter than did those in the control group. Anular shortening was reduced only in the group with moderate to severe TR and preserved in the other groups, including those with mild TR. The critical diameter was determined to be between the maximal diameter in the rheumatic patients without TR and the minimal diameter in the patients with moderate to severe TR, or 27 mm/m2. Thus this easily measured parameter can determine the presence and significance of functional TR, adding objectivity to the angiographic diagnosis of TR.