Preliminary analysis of right heart contrast echocardiography in healthy volunteers / 中华医学超声杂志（电子版）

ABSTRACT

Objective To explore the incidence of the right to left shunt (RLS) originated from patent foramen ovale (PFO) and/or pulmonary (PFO-RLS and/or P-RLS). Methods The transoesophageal echocardiography (TEE) and contrast transthoracic echocardiography (cTTE) were performed in 42 consecutive healthy adults. An agitated saline solution was used as contrast agent. According to the time that microbubbles (MB) occurred in the left atrium within or beyond the ifrst 3 cardiac cycles after contrast appearance in the right atrium, the RLS was identiifed as PFO-RLS or P-RLS. The RLS were semi-quantitated and graded in a three-level categorization according to the number of MB appearanced in the left atrium in every single frame imagelevel 1 indicated ≤10 MB, namely mild RLS;level 2 indicated 11-30 MB, namely moderate RLS and level 3 indicated>30 MB, namely severe RLS. The reseach mainly focused on(1) How many PFO and PFO-RLS existed in healthy adults? What was the size of PFO in healthy adults ? (2) Was there any P-RLS could be detected in healthy adults and what was the incidence of P-RLS ? (3) Was there any relationship between the RLS and Valsalva maneuver ? (4) The semi-quantitation and grading of the RLS originated from different sources. Results In 42 healthy adults, 13 cases (13/42, 30%) were diagnosed as PFO by TEE. The width of PFO was (1.46±0.18) mm (1-3 mm) and the length of PFO was (7.23±1.09) mm (4-14 mm). In 42 healthy adults, 30 cases (30/42, 71%) were diagnosed as RLS by cTTE. In 4 cases, the RLS were originated both from PFO and pulmanory, so ifnally there were 12 PFO-RLS (12/42, 29%) and 22 P-RLS (22/42, 52%). Most of PFO-RLS occurred during Valsalva maneuver, especially at the end of Valsalva maneuver, except 1 case in which PFO-RLS occurred at rest condition. Most of P-RLS occurred during rest condition (14) and few occurred after Valsalva maneuver (8). The incidence of PFO-RLS was lower than that of P-RLS. The difference between the two incidences was signiifcant (χ2=4.941, P=0.026). The diagnose for PFO was consistent in 11 cases between TEE and cTTE. But 2 cases were only diagnosed as PFO by TEE and 1 case were only diagnosed as PFO-RLS by cTTE. The semi-quantiifcation grading of RLS was signiifcant different between PFO-RLS and P-RLS (Z=-3.901, P=0.000). In 12 PFO-RLS, there were 6 cases in level 2 and 6 cases in level 3. In 22 P-RLS, there were 11 cases in level 1, 10 cases in level 2 and 1 case in level 3. Conclusions In healthy adults, PFO with a small amount RLS is common and its incidence is about a quarter. The detecting of PFO-RLS must be supplemented by a valsalva maneuve. In healthy adults, the P-RLS is also common and its semi-quantiifcation grading is lower than that of the PFO-RLS. The incidence, detecting inlfuence factor and the clinical signiifcant of the P-RLS are still not very clear and need more study.