Six-minute walk test distance and resting oxygen saturations but not functional class predict outcome in adult patients with Eisenmenger syndrome.
BACKGROUND
Eisenmenger syndrome (ES) represents the extreme manifestation of pulmonary arterial hypertension in patients with congenital heart disease, associated with significant exercise intolerance and mortality. Even though of six-minute-walk-test (6MWT) is routinely used in these patients, little is known about its prognostic value in comparison to functional class.


METHODS AND RESULTS
We included 210 adult patients with ES who underwent a total of 822 6MWTs. Median walking distance (6MWD) was 330 m [IQR 260-395], oxygen saturation (SO2) at baseline 86% [IQR 82-91%] and SO2 at peak-exercise 69% [IQR 60-80%]. In patients commenced on advanced therapy for pulmonary hypertension, but not in the reminder, there was a significant improvement in walking distance (297±97 m vs. 325±87 m,P=0.0019), SO2 at rest (84.9±7.1 vs. 86.8±5.9%,P=0.003), SO2 at peak exercise (69.1±12.7 vs. 72.3±12.2%,P=0.04) and NYHA functional class (P=0.0047). During a follow up of 3.3 years, 29 patients died. On time-dependent Cox analysis, 6MWD (HR 0.94 per 10 m, 95%CI: 0.91-0.97,P<0.001) and baseline SO2 (HR 0.90, 95%CI:0.86-0.94,P<0.0001) were predictors of death. In contrast, age, functional class, peak-exercise SO2 and SO2 change were not related to mortality. A three-fold increased risk of death was identified in patients not reaching a 6MWD of 350 m or with baseline SO2 below 85%.


CONCLUSIONS
The 6MWD and resting SO2, but not functional class were predictive of outcome in this contemporary cohort of Eisenmenger patients and should be incorporated in both risk stratification and management algorithms for these patients.
['Kempny|Aleksander|A|', 'Dimopoulos|Konstantinos|K|', 'Alonso-Gonzalez|Rafael|R|', 'Alvarez-Barredo|Maria|M|', 'Tutarel|Oktay|O|', 'Uebing|Anselm|A|', 'Piatek|Pawel|P|', 'Marino|Philip|P|', 'Swan|Lorna|L|', 'Diller|Gerhard-Paul|GP|', 'Wort|Stephen J|SJ|', 'Gatzoulis|Michael A|MA|']
D000328:Adult D018450:Disease Progression D004541:Eisenmenger Complex D005080:Exercise Test D017079:Exercise Tolerance D005260:Female D005500:Follow-Up Studies D006801:Humans D008297:Male D008875:Middle Aged D010101:Oxygen Consumption D011237:Predictive Value of Tests D011379:Prognosis D012189:Retrospective Studies D012307:Risk Factors D012720:Severity of Illness Index D015996:Survival Rate D006113:United Kingdom D016138:Walking D055815:Young Adult
Six-minute walk test Oxygen saturation Outcome Eisenmenger syndrome Adult congenital heart disease