Background
Two-dimensional and Doppler echocardiography are standard methods to assess the severity of pulmonic insufficiency (PI). However, methods to define severity of PI – including the current published guidelines – remain qualitative and unvalidated.
Methods
We reviewed all the electronic reports of echocardiographic studies performed at our institution since the publication of the 2003 American Society of Echocardiography guidelines on native valvular regurgitation. There were 8,279 instances of severe valvular insufficiency among 100,167 echocardiographic studies (approximately 90% transthoracic and 10% transesophageal). We also searched for uncommon findings of severe PI.
Results
Of all forms of severe valvular insufficiency, PI was least common. There were 135 instances of severe PI as defined by the existing guidelines; they accounted for only 1.6% of all instances of severe valvular insufficiency. Premature closure of the tricuspid valve was seen in 6.6%, holodiastolic flow reversal in 3.7%, premature opening of the pulmonic valve in 1.5%, PI with laminar retrograde flow in 1.5%, very low peak velocity of the PI jet in 1.5% of patients with severe PI.
Conclusions
The published criteria do not include in detail the subtle signs of severe PI such as (1) holodiastolic flow reversal in the pulmonary artery, (2) PI with laminar retrograde flow, (3) premature opening of the pulmonic valve, (4) very low peak velocity of the PI jet, and (5) premature closure of the tricuspid valve. These signs should be considered in the grading of PI severity in addition to the existing guidelines criteria.
Existing guidelines for grading the severity of pulmonic insufficiency (PI) rely on anatomic assessment of the pulmonic valve and right ventricle, color Doppler to determine regurgitant jet size, continuous-wave Doppler to determine jet density and deceleration rate, and pulsed-wave Doppler to compare systolic pulmonic flow with systemic flow. Several Doppler findings of severe PI are not well described in the current guidelines, and echocardiographers may not be familiar with these subtle findings. The purpose of this report is to describe uncommon, though clinically relevant, Doppler findings of severe PI that may help further define the severity of PI in addition to the existing guidelines. These echocardiographic findings also illustrate several hemodynamic principles related to severe PI.
Methods
We reviewed all the electronic reports of echocardiographic studies performed at our institution since the publication of the guidelines in 2003. A total of 100,167 echocardiographic studies, of which approximately 10% were transesophageal echocardiographic studies, were performed over the subsequent 6-year period. There were 8,279 instances of severe valvular insufficiency among these studies. Individual patients may have had severe insufficiency of more than one valve. These instances were identified by a review of echocardiographic reports. Of all forms of severe valvular insufficiency, PI was least common. There were 135 instances of severe PI as defined by the existing guidelines; they accounted for only 1.6% of all instances of severe valvular insufficiency. Of the 135 patients with severe PI, transesophageal echocardiography (in addition to transthoracic echocardiography) was performed in 14 of them.
On transthoracic echocardiography, the evaluation of the pulmonic valve was performed primarily on the parasternal short-axis view; however, occasionally, evaluation of the right ventricular infundibulum and pulmonic valve was performed from the short-axis subcostal view. The findings are summarized in Table 1 .
| Finding | Frequency |
|---|---|
| Mitral insufficiency | 50.5% |
| Tricuspid insufficiency | 33.8% |
| Aortic insufficiency | 14.0% |
| Pulmonic insufficiency | 1.6% |
In addition to traditional echocardiographic findings of severe PI documented in the guidelines, we also searched for uncommon findings of severe PI among our study patients. Examples of findings of severe PI found in this cohort are demonstrated below.
Results
Traditional Echocardiographic Findings of Severe PI
Two-dimensional transthoracic echocardiography of a patient with severe PI many years following surgical pulmonic valvulotomy demonstrated severe right ventricular dilation. A very wide vena contracta and a regurgitant jet that occupied a large area of the right ventricular outflow tract (approximately 70%) are demonstrated in Figure 1 and Video 1 ( 
view video clip online).
In addition, continuous-wave Doppler ( Figure 2 ) through the pulmonary valve demonstrated an intense PI flow signal, which was equal in intensity to the antegrade pulmonic valve flow signal. Figure 2 also demonstrates a steep deceleration of PI flow velocity. On transesophageal echocardiography, color M-mode imaging at the level of the pulmonic valve ( Figure 3 ) demonstrated most of the PI confined to early diastole because of rapid equalization of right ventricular and pulmonary artery diastolic pressures, also consistent with severe PI. These findings meet the existing criteria for grading severe PI.
Continuous-wave Doppler in the parasternal short-axis view on transthoracic echocardiography in another patient with severe PI ( Figure 4 ) demonstrated an intense signal with steep deceleration of PI flow velocity. In addition, there was increased antegrade velocity through the pulmonic valve (1.8 m/sec; normal < 1.3 m/sec). There was no evidence of pulmonic stenosis.
Less Common Findings of Severe PI
The following findings in severe PI are not well described in the current guidelines.
Holodiastolic Pulmonary Artery Flow Reversal
On transesophageal echocardiography in the first patient described with severe PI, pulsed-wave Doppler in the pulmonary artery with the sample volume placed 2 cm distal to the pulmonic valve demonstrated holodiastolic reversal of flow ( Figure 5 ). The ratio of the velocity-time integrals of retrograde to antegrade flow at this position suggested that approximately 60% to 70% of antegrade flow was regurgitated. More precise quantification of antegrade and retrograde stroke volume was limited by a nonparallel intercept angle with the regurgitant jet and unequal distribution of distal flow within the pulmonary artery. Holodiastolic flow reversal in the pulmonary artery was observed in five of 135 instances (3.7%) of severe PI in our series.
PI With Laminar Retrograde Flow
The pulsed-wave Doppler recordings shown in Figure 5 demonstrate a narrow range of velocities within the sample volume. This is consistent with laminar (nonturbulent) flow. Laminar flow of PI can also be observed by color Doppler imaging in a patient with a congenitally absent pulmonic valve, as demonstrated in Figure 6 . PI with laminar retrograde flow was documented in two of 135 instances (1.5%) of severe PI in our series.
Premature Opening of the Pulmonic Valve
Analysis with color Doppler of a patient with a congenitally absent pulmonic valve, as shown in Figure 6 and Video 2 ( view video clip online), demonstrated premature antegrade flow in the pulmonary artery at end-diastole ( Figure 7 ). Pulsed-wave Doppler with the sample volume in the proximal pulmonary artery demonstrated antegrade diastolic flow coinciding with atrial contraction ( Figure 8 ). The findings in Figures 7 and 8 are indicative of premature opening of the pulmonic valve. PI with premature opening of the pulmonic valve was documented in two of 135 instances (1.5%) of severe PI in our series.
