Noninvasive Echocardiographic Surrogate In Stiff Left Atrial Syndrome

Background Heart failure with preserved ejection fraction (HFpEF) includes a heterogenous assembly of people with combined left atrial (LA) and left ventricular (LV) diastolic dysfunction as well as people with isolated LA dysfunction. Diastolic abnormalities of the LA are poorly understood. Stiff LA syndrome, a process of reduced LA systolic compliance, causes right heart failure disproportionate to left heart failure and is not well defined by noninvasive measures. A few surrogates have noninvasively estimated LV filling pressure, notably E/e’, and LA strain, however they did not differentiate between LV and LA dysfunction. Here, we aimed to identify an echocardiographic measure that would discriminate between HFpEF secondary to stiff LA syndrome versus secondary to LV dysfunction. Methods We retrospectively analyzed 45 exercise right heart catheterizations (RHCs) performed at Scripps Clinic and identified those with stiff LA as defined by tall V waves in absence of mitral regurgitation, and those who have elevated wedge pressure but without evidence of stiff LA. We analyzed these patients’ transthoracic echocardiograms (TTEs) and performed strain imaging on the LA to identify parameters to predict stiff LA. Continuous variables were reported as means and standard deviations, and associations with stiff LA were tested via univariable logistic regression. The statistical software R v. 4.0.3 was used for all analyses and p-values less than 0.05 were considered statistically significant. Results Exercise RHCs in 45 patients with ejection fraction greater than 40% were evaluated, 19 of which were determined to have LV dysfunction in the absence stiff LA syndrome (Group 1) and 26 who had evidence of stiff LA syndrome (Group 2). Average age was 69 years, 60% were female, and 89% were white. 8 patients in Group 2 and 1 patient in Group 1 had atrial fibrillation. Mean wedge pressure at rest was 12.37 (SD +/-5.18) in Group 1 and 17.96 (SD +/-6.23) in Group 2. Mean wedge pressure at peak exercise was 21.25 (SD+/-9.66) in Group 1 and 30.15 (SD +/-6.27) in Group 2. LA reservoir mean was 22.64 in Group 1 (SD +/- 8.88) vs 14.90 in group 2 (SD +/- 8.7). LA reservoir was associated with greater odds of having stiff LA vs not, odds ratio (OR)=0.90 (CI 0.82 - 0.97, p= 0.014). LA contractile mean was -10.31 in Group 1 (SD +/- 6.04) vs -5.12 in group 2 (SD +/- 5.60). LA contractile strain was associated with greater odds of having stiff LA vs not, OR=1.19 (CI 1.04-1.42, p=0.028) Conclusion LA strain imaging was able to differentiate between patients with stiff LA versus those with LV diastolic dysfunction during RHC. Heart failure with preserved ejection fraction (HFpEF) includes a heterogenous assembly of people with combined left atrial (LA) and left ventricular (LV) diastolic dysfunction as well as people with isolated LA dysfunction. Diastolic abnormalities of the LA are poorly understood. Stiff LA syndrome, a process of reduced LA systolic compliance, causes right heart failure disproportionate to left heart failure and is not well defined by noninvasive measures. A few surrogates have noninvasively estimated LV filling pressure, notably E/e’, and LA strain, however they did not differentiate between LV and LA dysfunction. Here, we aimed to identify an echocardiographic measure that would discriminate between HFpEF secondary to stiff LA syndrome versus secondary to LV dysfunction. We retrospectively analyzed 45 exercise right heart catheterizations (RHCs) performed at Scripps Clinic and identified those with stiff LA as defined by tall V waves in absence of mitral regurgitation, and those who have elevated wedge pressure but without evidence of stiff LA. We analyzed these patients’ transthoracic echocardiograms (TTEs) and performed strain imaging on the LA to identify parameters to predict stiff LA. Continuous variables were reported as means and standard deviations, and associations with stiff LA were tested via univariable logistic regression. The statistical software R v. 4.0.3 was used for all analyses and p-values less than 0.05 were considered statistically significant. Exercise RHCs in 45 patients with ejection fraction greater than 40% were evaluated, 19 of which were determined to have LV dysfunction in the absence stiff LA syndrome (Group 1) and 26 who had evidence of stiff LA syndrome (Group 2). Average age was 69 years, 60% were female, and 89% were white. 8 patients in Group 2 and 1 patient in Group 1 had atrial fibrillation. Mean wedge pressure at rest was 12.37 (SD +/-5.18) in Group 1 and 17.96 (SD +/-6.23) in Group 2. Mean wedge pressure at peak exercise was 21.25 (SD+/-9.66) in Group 1 and 30.15 (SD +/-6.27) in Group 2. LA reservoir mean was 22.64 in Group 1 (SD +/- 8.88) vs 14.90 in group 2 (SD +/- 8.7). LA reservoir was associated with greater odds of having stiff LA vs not, odds ratio (OR)=0.90 (CI 0.82 - 0.97, p= 0.014). LA contractile mean was -10.31 in Group 1 (SD +/- 6.04) vs -5.12 in group 2 (SD +/- 5.60). LA contractile strain was associated with greater odds of having stiff LA vs not, OR=1.19 (CI 1.04-1.42, p=0.028) LA strain imaging was able to differentiate between patients with stiff LA versus those with LV diastolic dysfunction during RHC.